Merge branch 'master' of git.sv.gnu.org:/srv/git/emacs

[gnu-emacs] / lisp / net / tramp-sh.el

;;; tramp-sh.el --- Tramp access functions for (s)sh-like connections

;; Copyright (C) 1998-2016 Free Software Foundation, Inc.

;; (copyright statements below in code to be updated with the above notice)

;; Author: Kai Großjohann <kai.grossjohann@gmx.net>
;;         Michael Albinus <michael.albinus@gmx.de>
;; Keywords: comm, processes
;; Package: tramp

;; This file is part of GNU Emacs.

;; GNU Emacs is free software: you can redistribute it and/or modify
;; it under the terms of the GNU General Public License as published by
;; the Free Software Foundation, either version 3 of the License, or
;; (at your option) any later version.

;; GNU Emacs is distributed in the hope that it will be useful,
;; but WITHOUT ANY WARRANTY; without even the implied warranty of
;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
;; GNU General Public License for more details.

;; You should have received a copy of the GNU General Public License
;; along with GNU Emacs.  If not, see <http://www.gnu.org/licenses/>.

;;; Code:

(require 'tramp)

;; Pacify byte-compiler.
(eval-when-compile
  (require 'cl)
  (require 'dired))
(defvar tramp-gw-tunnel-method)
(defvar tramp-gw-socks-method)
(defvar vc-handled-backends)
(defvar vc-bzr-program)
(defvar vc-git-program)
(defvar vc-hg-program)

;;;###tramp-autoload
(defcustom tramp-inline-compress-start-size 4096
  "The minimum size of compressing where inline transfer.
When inline transfer, compress transferred data of file
whose size is this value or above (up to `tramp-copy-size-limit').
If it is nil, no compression at all will be applied."
  :group 'tramp
  :type '(choice (const nil) integer))

;;;###tramp-autoload
(defcustom tramp-copy-size-limit 10240
  "The maximum file size where inline copying is preferred over an \
out-of-the-band copy.
If it is nil, out-of-the-band copy will be used without a check."
  :group 'tramp
  :type '(choice (const nil) integer))

;;;###tramp-autoload
(defcustom tramp-terminal-type "dumb"
  "Value of TERM environment variable for logging in to remote host.
Because Tramp wants to parse the output of the remote shell, it is easily
confused by ANSI color escape sequences and suchlike.  Often, shell init
files conditionalize this setup based on the TERM environment variable."
  :group 'tramp
  :type 'string)

;;;###tramp-autoload
(defcustom tramp-histfile-override ".tramp_history"
  "When invoking a shell, override the HISTFILE with this value.
When setting to a string, it redirects the shell history to that
file.  Be careful when setting to \"/dev/null\"; this might
result in undesired results when using \"bash\" as shell.

The value t, the default value, unsets any setting of HISTFILE,
and sets both HISTFILESIZE and HISTSIZE to 0.  If you set this
variable to nil, however, the *override* is disabled, so the
history will go to the default storage location,
e.g. \"$HOME/.sh_history\"."
  :group 'tramp
  :version "25.1"
  :type '(choice (const :tag "Do not override HISTFILE" nil)
                 (const :tag "Unset HISTFILE" t)
                 (string :tag "Redirect to a file")))

;;;###tramp-autoload
(defconst tramp-display-escape-sequence-regexp "\e[[;0-9]+m"
  "Terminal control escape sequences for display attributes.")

;;;###tramp-autoload
(defconst tramp-device-escape-sequence-regexp "\e[[0-9]+n"
  "Terminal control escape sequences for device status.")

;; ksh on OpenBSD 4.5 requires that $PS1 contains a `#' character for
;; root users.  It uses the `$' character for other users.  In order
;; to guarantee a proper prompt, we use "#$ " for the prompt.

(defvar tramp-end-of-output
  (format
   "///%s#$"
   (md5 (concat (prin1-to-string process-environment) (current-time-string))))
  "String used to recognize end of output.
The `$' character at the end is quoted; the string cannot be
detected as prompt when being sent on echoing hosts, therefore.")

;;;###tramp-autoload
(defconst tramp-initial-end-of-output "#$ "
  "Prompt when establishing a connection.")

(defconst tramp-end-of-heredoc (md5 tramp-end-of-output)
  "String used to recognize end of heredoc strings.")

;;;###tramp-autoload
(defcustom tramp-use-ssh-controlmaster-options t
  "Whether to use `tramp-ssh-controlmaster-options'."
  :group 'tramp
  :version "24.4"
  :type 'boolean)

(defvar tramp-ssh-controlmaster-options nil
  "Which ssh Control* arguments to use.

If it is a string, it should have the form
\"-o ControlMaster=auto -o ControlPath=\\='tramp.%%r@%%h:%%p\\='
-o ControlPersist=no\".  Percent characters in the ControlPath
spec must be doubled, because the string is used as format string.

Otherwise, it will be auto-detected by Tramp, if
`tramp-use-ssh-controlmaster-options' is non-nil.  The value
depends on the installed local ssh version.

The string is used in `tramp-methods'.")

;; Initialize `tramp-methods' with the supported methods.
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("rcp"
    (tramp-login-program        "rsh")
    (tramp-login-args           (("%h") ("-l" "%u")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "rcp")
    (tramp-copy-args            (("-p" "%k") ("-r")))
    (tramp-copy-keep-date       t)
    (tramp-copy-recursive       t)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("remcp"
    (tramp-login-program        "remsh")
    (tramp-login-args           (("%h") ("-l" "%u")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "rcp")
    (tramp-copy-args            (("-p" "%k")))
    (tramp-copy-keep-date       t)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("scp"
    (tramp-login-program        "ssh")
    (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
                                 ("-e" "none") ("%h")))
    (tramp-async-args           (("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "scp")
    (tramp-copy-args            (("-P" "%p") ("-p" "%k") ("-q") ("-r") ("%c")))
    (tramp-copy-keep-date       t)
    (tramp-copy-recursive       t)
    (tramp-gw-args              (("-o" "GlobalKnownHostsFile=/dev/null")
                                 ("-o" "UserKnownHostsFile=/dev/null")
                                 ("-o" "StrictHostKeyChecking=no")))
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("scpx"
    (tramp-login-program        "ssh")
    (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
                                 ("-e" "none") ("-t" "-t") ("%h") ("/bin/sh")))
    (tramp-async-args           (("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "scp")
    (tramp-copy-args            (("-P" "%p") ("-p" "%k")
                                 ("-q") ("-r") ("%c")))
    (tramp-copy-keep-date       t)
    (tramp-copy-recursive       t)
    (tramp-gw-args              (("-o" "GlobalKnownHostsFile=/dev/null")
                                 ("-o" "UserKnownHostsFile=/dev/null")
                                 ("-o" "StrictHostKeyChecking=no")))
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("rsync"
    (tramp-login-program        "ssh")
    (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
                                 ("-e" "none") ("%h")))
    (tramp-async-args           (("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "rsync")
    (tramp-copy-args            (("-t" "%k") ("-r")))
    (tramp-copy-env             (("RSYNC_RSH") ("ssh" "%c")))
    (tramp-copy-keep-date       t)
    (tramp-copy-keep-tmpfile    t)
    (tramp-copy-recursive       t)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("rsh"
    (tramp-login-program        "rsh")
    (tramp-login-args           (("%h") ("-l" "%u")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("remsh"
    (tramp-login-program        "remsh")
    (tramp-login-args           (("%h") ("-l" "%u")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("ssh"
    (tramp-login-program        "ssh")
    (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
                                 ("-e" "none") ("%h")))
    (tramp-async-args           (("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-gw-args              (("-o" "GlobalKnownHostsFile=/dev/null")
                                 ("-o" "UserKnownHostsFile=/dev/null")
                                 ("-o" "StrictHostKeyChecking=no")))
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("sshx"
    (tramp-login-program        "ssh")
    (tramp-login-args           (("-l" "%u") ("-p" "%p") ("%c")
                                 ("-e" "none") ("-t" "-t") ("%h") ("/bin/sh")))
    (tramp-async-args           (("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-gw-args              (("-o" "GlobalKnownHostsFile=/dev/null")
                                 ("-o" "UserKnownHostsFile=/dev/null")
                                 ("-o" "StrictHostKeyChecking=no")))
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("telnet"
    (tramp-login-program        "telnet")
    (tramp-login-args           (("%h") ("%p") ("2>/dev/null")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-default-port         23)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("nc"
    (tramp-login-program        "telnet")
    (tramp-login-args           (("%h") ("%p") ("2>/dev/null")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "nc")
    ;; We use "-v" for better error tracking.
    (tramp-copy-args            (("-w" "1") ("-v") ("%h") ("%r")))
    (tramp-remote-copy-program  "nc")
    ;; We use "-p" as required for newer busyboxes.  For older
    ;; busybox/nc versions, the value must be (("-l") ("%r")).  This
    ;; can be achieved by tweaking `tramp-connection-properties'.
    (tramp-remote-copy-args     (("-l") ("-p" "%r") ("2>/dev/null")))
    (tramp-default-port         23)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("su"
    (tramp-login-program        "su")
    (tramp-login-args           (("-") ("%u")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-connection-timeout   10)))
;;;###tramp-autoload
(add-to-list
 'tramp-methods
 '("sg"
   (tramp-login-program        "sg")
   (tramp-login-args           (("-") ("%u")))
   (tramp-remote-shell         "/bin/sh")
   (tramp-remote-shell-args    ("-c"))
   (tramp-connection-timeout   10)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("sudo"
    (tramp-login-program        "sudo")
    ;; The password template must be masked.  Otherwise, it could be
    ;; interpreted as password prompt if the remote host echoes the command.
    (tramp-login-args           (("-u" "%u") ("-s") ("-H")
                                 ("-p" "P\"\"a\"\"s\"\"s\"\"w\"\"o\"\"r\"\"d\"\":")))
    ;; Local $SHELL could be a nasty one, like zsh or fish.  Let's override it.
    (tramp-login-env            (("SHELL") ("/bin/sh")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-connection-timeout   10)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("doas"
    (tramp-login-program        "doas")
    (tramp-login-args           (("-u" "%u") ("-s")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-args    ("-c"))
    (tramp-connection-timeout   10)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("ksu"
    (tramp-login-program        "ksu")
    (tramp-login-args           (("%u") ("-q")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-connection-timeout   10)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("krlogin"
    (tramp-login-program        "krlogin")
    (tramp-login-args           (("%h") ("-l" "%u") ("-x")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  `("plink"
    (tramp-login-program        "plink")
    ;; ("%h") must be a single element, see `tramp-compute-multi-hops'.
    (tramp-login-args           (("-l" "%u") ("-P" "%p") ("-ssh") ("-t")
                                 ("%h") ("\"")
                                 (,(format
                                    "env 'TERM=%s' 'PROMPT_COMMAND=' 'PS1=%s'"
                                    tramp-terminal-type
                                    tramp-initial-end-of-output))
                                 ("/bin/sh") ("\"")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  `("plinkx"
    (tramp-login-program        "plink")
    (tramp-login-args           (("-load") ("%h") ("-t") ("\"")
                                 (,(format
                                    "env 'TERM=%s' 'PROMPT_COMMAND=' 'PS1=%s'"
                                    tramp-terminal-type
                                    tramp-initial-end-of-output))
                                 ("/bin/sh") ("\"")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  `("pscp"
    (tramp-login-program        "plink")
    (tramp-login-args           (("-l" "%u") ("-P" "%p") ("-ssh") ("-t")
                                 ("%h") ("\"")
                                 (,(format
                                    "env 'TERM=%s' 'PROMPT_COMMAND=' 'PS1=%s'"
                                    tramp-terminal-type
                                    tramp-initial-end-of-output))
                                 ("/bin/sh") ("\"")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "pscp")
    (tramp-copy-args            (("-l" "%u") ("-P" "%p") ("-scp") ("-p" "%k")
                                 ("-q") ("-r")))
    (tramp-copy-keep-date       t)
    (tramp-copy-recursive       t)
    (tramp-default-port         22)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  `("psftp"
    (tramp-login-program        "plink")
    (tramp-login-args           (("-l" "%u") ("-P" "%p") ("-ssh") ("-t")
                                 ("%h") ("\"")
                                 (,(format
                                    "env 'TERM=%s' 'PROMPT_COMMAND=' 'PS1=%s'"
                                    tramp-terminal-type
                                    tramp-initial-end-of-output))
                                 ("/bin/sh") ("\"")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-c"))
    (tramp-copy-program         "pscp")
    (tramp-copy-args            (("-l" "%u") ("-P" "%p") ("-sftp") ("-p" "%k")
                                 ("-q")))
    (tramp-copy-keep-date       t)))
;;;###tramp-autoload
(add-to-list 'tramp-methods
  '("fcp"
    (tramp-login-program        "fsh")
    (tramp-login-args           (("%h") ("-l" "%u") ("sh" "-i")))
    (tramp-remote-shell         "/bin/sh")
    (tramp-remote-shell-login   ("-l"))
    (tramp-remote-shell-args    ("-i") ("-c"))
    (tramp-copy-program         "fcp")
    (tramp-copy-args            (("-p" "%k")))
    (tramp-copy-keep-date       t)))

;;;###tramp-autoload
(add-to-list 'tramp-default-method-alist
             `(,tramp-local-host-regexp "\\`root\\'" "su"))

;;;###tramp-autoload
(add-to-list 'tramp-default-user-alist
             `(,(concat "\\`" (regexp-opt '("su" "sudo" "doas" "ksu")) "\\'")
               nil "root"))
;; Do not add "ssh" based methods, otherwise ~/.ssh/config would be ignored.
;; Do not add "plink" based methods, they ask interactively for the user.
;;;###tramp-autoload
(add-to-list 'tramp-default-user-alist
             `(,(concat
                 "\\`"
                 (regexp-opt
                  '("rcp" "remcp" "rsh" "telnet" "nc" "krlogin" "fcp"))
                 "\\'")
               nil ,(user-login-name)))

;;;###tramp-autoload
(defconst tramp-completion-function-alist-rsh
  '((tramp-parse-rhosts "/etc/hosts.equiv")
    (tramp-parse-rhosts "~/.rhosts"))
  "Default list of (FUNCTION FILE) pairs to be examined for rsh methods.")

;;;###tramp-autoload
(defconst tramp-completion-function-alist-ssh
  '((tramp-parse-rhosts      "/etc/hosts.equiv")
    (tramp-parse-rhosts      "/etc/shosts.equiv")
    (tramp-parse-shosts      "/etc/ssh_known_hosts")
    (tramp-parse-sconfig     "/etc/ssh_config")
    (tramp-parse-shostkeys   "/etc/ssh2/hostkeys")
    (tramp-parse-sknownhosts "/etc/ssh2/knownhosts")
    (tramp-parse-rhosts      "~/.rhosts")
    (tramp-parse-rhosts      "~/.shosts")
    (tramp-parse-shosts      "~/.ssh/known_hosts")
    (tramp-parse-sconfig     "~/.ssh/config")
    (tramp-parse-shostkeys   "~/.ssh2/hostkeys")
    (tramp-parse-sknownhosts "~/.ssh2/knownhosts"))
  "Default list of (FUNCTION FILE) pairs to be examined for ssh methods.")

;;;###tramp-autoload
(defconst tramp-completion-function-alist-telnet
  '((tramp-parse-hosts "/etc/hosts"))
  "Default list of (FUNCTION FILE) pairs to be examined for telnet methods.")

;;;###tramp-autoload
(defconst tramp-completion-function-alist-su
  '((tramp-parse-passwd "/etc/passwd"))
  "Default list of (FUNCTION FILE) pairs to be examined for su methods.")

;;;###tramp-autoload
(defconst tramp-completion-function-alist-sg
  '((tramp-parse-etc-group "/etc/group"))
  "Default list of (FUNCTION FILE) pairs to be examined for sg methods.")

;;;###tramp-autoload
(defconst tramp-completion-function-alist-putty
  `((tramp-parse-putty
     ,(if (memq system-type '(windows-nt))
          "HKEY_CURRENT_USER\\Software\\SimonTatham\\PuTTY\\Sessions"
        "~/.putty/sessions")))
 "Default list of (FUNCTION REGISTRY) pairs to be examined for putty sessions.")

;;;###tramp-autoload
(eval-after-load 'tramp
  '(progn
     (tramp-set-completion-function "rcp" tramp-completion-function-alist-rsh)
     (tramp-set-completion-function "remcp" tramp-completion-function-alist-rsh)
     (tramp-set-completion-function "scp" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "scpx" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "rsync" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "rsh" tramp-completion-function-alist-rsh)
     (tramp-set-completion-function "remsh" tramp-completion-function-alist-rsh)
     (tramp-set-completion-function "ssh" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "sshx" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function
      "telnet" tramp-completion-function-alist-telnet)
     (tramp-set-completion-function "nc" tramp-completion-function-alist-telnet)
     (tramp-set-completion-function "su" tramp-completion-function-alist-su)
     (tramp-set-completion-function "sudo" tramp-completion-function-alist-su)
     (tramp-set-completion-function "doas" tramp-completion-function-alist-su)
     (tramp-set-completion-function "ksu" tramp-completion-function-alist-su)
     (tramp-set-completion-function "sg" tramp-completion-function-alist-sg)
     (tramp-set-completion-function
      "krlogin" tramp-completion-function-alist-rsh)
     (tramp-set-completion-function "plink" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function
      "plinkx" tramp-completion-function-alist-putty)
     (tramp-set-completion-function "pscp" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "psftp" tramp-completion-function-alist-ssh)
     (tramp-set-completion-function "fcp" tramp-completion-function-alist-ssh)))

;; "getconf PATH" yields:
;; HP-UX: /usr/bin:/usr/ccs/bin:/opt/ansic/bin:/opt/langtools/bin:/opt/fortran/bin
;; Solaris: /usr/xpg4/bin:/usr/ccs/bin:/usr/bin:/opt/SUNWspro/bin
;; GNU/Linux (Debian, Suse, RHEL): /bin:/usr/bin
;; FreeBSD: /usr/bin:/bin:/usr/sbin:/sbin: - beware trailing ":"!
;; Darwin: /usr/bin:/bin:/usr/sbin:/sbin
;; IRIX64: /usr/bin
;;;###tramp-autoload
(defcustom tramp-remote-path
  '(tramp-default-remote-path "/bin" "/usr/bin" "/sbin" "/usr/sbin"
    "/usr/local/bin" "/usr/local/sbin" "/local/bin" "/local/freeware/bin"
    "/local/gnu/bin" "/usr/freeware/bin" "/usr/pkg/bin" "/usr/contrib/bin"
    "/opt/bin" "/opt/sbin" "/opt/local/bin")
  "List of directories to search for executables on remote host.
For every remote host, this variable will be set buffer local,
keeping the list of existing directories on that host.

You can use `~' in this list, but when searching for a shell which groks
tilde expansion, all directory names starting with `~' will be ignored.

`Default Directories' represent the list of directories given by
the command \"getconf PATH\".  It is recommended to use this
entry on top of this list, because these are the default
directories for POSIX compatible commands.  On remote hosts which
do not offer the getconf command (like cygwin), the value
\"/bin:/usr/bin\" is used instead of.

`Private Directories' are the settings of the $PATH environment,
as given in your `~/.profile'."
  :group 'tramp
  :type '(repeat (choice
                  (const :tag "Default Directories" tramp-default-remote-path)
                  (const :tag "Private Directories" tramp-own-remote-path)
                  (string :tag "Directory"))))

;;;###tramp-autoload
(defcustom tramp-remote-process-environment
  `("TMOUT=0" "LC_CTYPE=''"
    ,(format "TERM=%s" tramp-terminal-type)
    ,(format "INSIDE_EMACS='%s,tramp:%s'" emacs-version tramp-version)
    "CDPATH=" "HISTORY=" "MAIL=" "MAILCHECK=" "MAILPATH=" "PAGER=cat"
    "autocorrect=" "correct=")
  "List of environment variables to be set on the remote host.

Each element should be a string of the form ENVVARNAME=VALUE.  An
entry ENVVARNAME= disables the corresponding environment variable,
which might have been set in the init files like ~/.profile.

Special handling is applied to the PATH environment, which should
not be set here. Instead, it should be set via `tramp-remote-path'."
  :group 'tramp
  :version "24.4"
  :type '(repeat string))

;;;###tramp-autoload
(defcustom tramp-sh-extra-args '(("/bash\\'" . "-norc -noprofile"))
  "Alist specifying extra arguments to pass to the remote shell.
Entries are (REGEXP . ARGS) where REGEXP is a regular expression
matching the shell file name and ARGS is a string specifying the
arguments.

This variable is only used when Tramp needs to start up another shell
for tilde expansion.  The extra arguments should typically prevent the
shell from reading its init file."
  :group 'tramp
  ;; This might be the wrong way to test whether the widget type
  ;; `alist' is available.  Who knows the right way to test it?
  :type (if (get 'alist 'widget-type)
            '(alist :key-type string :value-type string)
          '(repeat (cons string string))))

(defconst tramp-actions-before-shell
  '((tramp-login-prompt-regexp tramp-action-login)
    (tramp-password-prompt-regexp tramp-action-password)
    (tramp-wrong-passwd-regexp tramp-action-permission-denied)
    (shell-prompt-pattern tramp-action-succeed)
    (tramp-shell-prompt-pattern tramp-action-succeed)
    (tramp-yesno-prompt-regexp tramp-action-yesno)
    (tramp-yn-prompt-regexp tramp-action-yn)
    (tramp-terminal-prompt-regexp tramp-action-terminal)
    (tramp-process-alive-regexp tramp-action-process-alive))
  "List of pattern/action pairs.
Whenever a pattern matches, the corresponding action is performed.
Each item looks like (PATTERN ACTION).

The PATTERN should be a symbol, a variable.  The value of this
variable gives the regular expression to search for.  Note that the
regexp must match at the end of the buffer, \"\\'\" is implicitly
appended to it.

The ACTION should also be a symbol, but a function.  When the
corresponding PATTERN matches, the ACTION function is called.")

(defconst tramp-actions-copy-out-of-band
  '((tramp-password-prompt-regexp tramp-action-password)
    (tramp-wrong-passwd-regexp tramp-action-permission-denied)
    (tramp-copy-failed-regexp tramp-action-permission-denied)
    (tramp-process-alive-regexp tramp-action-out-of-band))
  "List of pattern/action pairs.
This list is used for copying/renaming with out-of-band methods.

See `tramp-actions-before-shell' for more info.")

(defconst tramp-uudecode
  "(echo begin 600 %t; tail -n +2) | uudecode
cat %t
rm -f %t"
  "Shell function to implement `uudecode' to standard output.
Many systems support `uudecode -o /dev/stdout' or `uudecode -o -'
for this or `uudecode -p', but some systems don't, and for them
we have this shell function.")

(defconst tramp-perl-file-truename
  "%s -e '
use File::Spec;
use Cwd \"realpath\";

sub myrealpath {
    my ($file) = @_;
    return realpath($file) if -e $file;
}

sub recursive {
    my ($volume, @dirs) = @_;
    my $real = myrealpath(File::Spec->catpath(
                   $volume, File::Spec->catdir(@dirs), \"\"));
    if ($real) {
        my ($vol, $dir) = File::Spec->splitpath($real, 1);
        return ($vol, File::Spec->splitdir($dir));
    }
    else {
        my $last = pop(@dirs);
        ($volume, @dirs) = recursive($volume, @dirs);
        push(@dirs, $last);
        return ($volume, @dirs);
    }
}

$result = myrealpath($ARGV[0]);
if (!$result) {
    my ($vol, $dir) = File::Spec->splitpath($ARGV[0], 1);
    ($vol, @dirs) = recursive($vol, File::Spec->splitdir($dir));

    $result = File::Spec->catpath($vol, File::Spec->catdir(@dirs), \"\");
}

$result =~ s/\"/\\\\\"/g;
print \"\\\"$result\\\"\\n\";
' \"$1\" 2>/dev/null"
  "Perl script to produce output suitable for use with `file-truename'
on the remote file system.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-perl-file-name-all-completions
  "%s -e '
opendir(d, $ARGV[0]) || die(\"$ARGV[0]: $!\\nfail\\n\");
@files = readdir(d); closedir(d);
foreach $f (@files) {
 if (-d \"$ARGV[0]/$f\") {
  print \"$f/\\n\";
 }
 else {
  print \"$f\\n\";
 }
}
print \"ok\\n\"
' \"$1\" 2>/dev/null"
  "Perl script to produce output suitable for use with
`file-name-all-completions' on the remote file system.  Escape
sequence %s is replaced with name of Perl binary.  This string is
passed to `format', so percent characters need to be doubled.")

;; Perl script to implement `file-attributes' in a Lisp `read'able
;; output.  If you are hacking on this, note that you get *no* output
;; unless this spits out a complete line, including the '\n' at the
;; end.
;; The device number is returned as "-1", because there will be a virtual
;; device number set in `tramp-sh-handle-file-attributes'.
(defconst tramp-perl-file-attributes
  "%s -e '
@stat = lstat($ARGV[0]);
if (!@stat) {
    print \"nil\\n\";
    exit 0;
}
if (($stat[2] & 0170000) == 0120000)
{
    $type = readlink($ARGV[0]);
    $type =~ s/\"/\\\\\"/g;
    $type = \"\\\"$type\\\"\";
}
elsif (($stat[2] & 0170000) == 040000)
{
    $type = \"t\";
}
else
{
    $type = \"nil\"
};
$uid = ($ARGV[1] eq \"integer\") ? $stat[4] : \"\\\"\" . getpwuid($stat[4]) . \"\\\"\";
$gid = ($ARGV[1] eq \"integer\") ? $stat[5] : \"\\\"\" . getgrgid($stat[5]) . \"\\\"\";
printf(
    \"(%%s %%u %%s %%s (%%u %%u) (%%u %%u) (%%u %%u) %%u.0 %%u t (%%u . %%u) -1)\\n\",
    $type,
    $stat[3],
    $uid,
    $gid,
    $stat[8] >> 16 & 0xffff,
    $stat[8] & 0xffff,
    $stat[9] >> 16 & 0xffff,
    $stat[9] & 0xffff,
    $stat[10] >> 16 & 0xffff,
    $stat[10] & 0xffff,
    $stat[7],
    $stat[2],
    $stat[1] >> 16 & 0xffff,
    $stat[1] & 0xffff
);' \"$1\" \"$2\" 2>/dev/null"
  "Perl script to produce output suitable for use with `file-attributes'
on the remote file system.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-perl-directory-files-and-attributes
  "%s -e '
chdir($ARGV[0]) or printf(\"\\\"Cannot change to $ARGV[0]: $''!''\\\"\\n\"), exit();
opendir(DIR,\".\") or printf(\"\\\"Cannot open directory $ARGV[0]: $''!''\\\"\\n\"), exit();
@list = readdir(DIR);
closedir(DIR);
$n = scalar(@list);
printf(\"(\\n\");
for($i = 0; $i < $n; $i++)
{
    $filename = $list[$i];
    @stat = lstat($filename);
    if (($stat[2] & 0170000) == 0120000)
    {
        $type = readlink($filename);
        $type =~ s/\"/\\\\\"/g;
        $type = \"\\\"$type\\\"\";
    }
    elsif (($stat[2] & 0170000) == 040000)
    {
        $type = \"t\";
    }
    else
    {
        $type = \"nil\"
    };
    $uid = ($ARGV[1] eq \"integer\") ? $stat[4] : \"\\\"\" . getpwuid($stat[4]) . \"\\\"\";
    $gid = ($ARGV[1] eq \"integer\") ? $stat[5] : \"\\\"\" . getgrgid($stat[5]) . \"\\\"\";
    $filename =~ s/\"/\\\\\"/g;
    printf(
        \"(\\\"%%s\\\" %%s %%u %%s %%s (%%u %%u) (%%u %%u) (%%u %%u) %%u.0 %%u t (%%u . %%u) (%%u . %%u))\\n\",
        $filename,
        $type,
        $stat[3],
        $uid,
        $gid,
        $stat[8] >> 16 & 0xffff,
        $stat[8] & 0xffff,
        $stat[9] >> 16 & 0xffff,
        $stat[9] & 0xffff,
        $stat[10] >> 16 & 0xffff,
        $stat[10] & 0xffff,
        $stat[7],
        $stat[2],
        $stat[1] >> 16 & 0xffff,
        $stat[1] & 0xffff,
        $stat[0] >> 16 & 0xffff,
        $stat[0] & 0xffff);
}
printf(\")\\n\");' \"$1\" \"$2\" 2>/dev/null"
  "Perl script implementing `directory-files-attributes' as Lisp `read'able
output.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.")

;; These two use base64 encoding.
(defconst tramp-perl-encode-with-module
  "%s -MMIME::Base64 -0777 -ne 'print encode_base64($_)' 2>/dev/null"
  "Perl program to use for encoding a file.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.
This implementation requires the MIME::Base64 Perl module to be installed
on the remote host.")

(defconst tramp-perl-decode-with-module
  "%s -MMIME::Base64 -0777 -ne 'print decode_base64($_)' 2>/dev/null"
  "Perl program to use for decoding a file.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.
This implementation requires the MIME::Base64 Perl module to be installed
on the remote host.")

(defconst tramp-perl-encode
  "%s -e '
# This script contributed by Juanma Barranquero <lektu@terra.es>.
# Copyright (C) 2002-2016 Free Software Foundation, Inc.
use strict;

my %%trans = do {
    my $i = 0;
    map {(substr(unpack(q(B8), chr $i++), 2, 6), $_)}
      split //, q(ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/);
};
my $data;

# We read in chunks of 54 bytes, to generate output lines
# of 72 chars (plus end of line)
while (read STDIN, $data, 54) {
    my $pad = q();

    # Only for the last chunk, and only if did not fill the last three-byte packet
    if (eof) {
        my $mod = length($data) %% 3;
        $pad = q(=) x (3 - $mod) if $mod;
    }

    # Not the fastest method, but it is simple: unpack to binary string, split
    # by groups of 6 bits and convert back from binary to byte; then map into
    # the translation table
    print
      join q(),
        map($trans{$_},
            (substr(unpack(q(B*), $data) . q(00000), 0, 432) =~ /....../g)),
              $pad,
                qq(\\n);
}' 2>/dev/null"
  "Perl program to use for encoding a file.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-perl-decode
  "%s -e '
# This script contributed by Juanma Barranquero <lektu@terra.es>.
# Copyright (C) 2002-2016 Free Software Foundation, Inc.
use strict;

my %%trans = do {
    my $i = 0;
    map {($_, substr(unpack(q(B8), chr $i++), 2, 6))}
      split //, q(ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/)
};

my %%bytes = map {(unpack(q(B8), chr $_), chr $_)} 0 .. 255;

binmode(\\*STDOUT);

# We are going to accumulate into $pending to accept any line length
# (we do not check they are <= 76 chars as the RFC says)
my $pending = q();

while (my $data = <STDIN>) {
    chomp $data;

    # If we find one or two =, we have reached the end and
    # any following data is to be discarded
    my $finished = $data =~ s/(==?).*/$1/;
    $pending .= $data;

    my $len = length($pending);
    my $chunk = substr($pending, 0, $len & ~3);
    $pending = substr($pending, $len & ~3 + 1);

    # Easy method: translate from chars to (pregenerated) six-bit packets, join,
    # split in 8-bit chunks and convert back to char.
    print join q(),
      map $bytes{$_},
        ((join q(), map {$trans{$_} || q()} split //, $chunk) =~ /......../g);

    last if $finished;
}' 2>/dev/null"
  "Perl program to use for decoding a file.
Escape sequence %s is replaced with name of Perl binary.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-perl-pack
  "%s -e 'binmode STDIN; binmode STDOUT; print pack(q{u*}, join q{}, <>)'"
  "Perl program to use for encoding a file.
Escape sequence %s is replaced with name of Perl binary.")

(defconst tramp-perl-unpack
  "%s -e 'binmode STDIN; binmode STDOUT; print unpack(q{u*}, join q{}, <>)'"
  "Perl program to use for decoding a file.
Escape sequence %s is replaced with name of Perl binary.")

(defconst tramp-awk-encode
  "od -v -t x1 -A n | busybox awk '\\
BEGIN {
  b64 = \"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\"
  b16 = \"0123456789abcdef\"
}
{
  for (c=1; c<=length($0); c++) {
    d=index(b16, substr($0,c,1))
    if (d--) {
      for (b=1; b<=4; b++) {
        o=o*2+int(d/8); d=(d*2)%%16
        if (++obc==6) {
          printf substr(b64,o+1,1)
          if (++rc>75) { printf \"\\n\"; rc=0 }
          obc=0; o=0
        }
      }
    }
  }
}
END {
  if (obc) {
    tail=(obc==2) ? \"==\\n\" : \"=\\n\"
    while (obc++<6) { o=o*2 }
    printf \"%%c\", substr(b64,o+1,1)
  } else {
    tail=\"\\n\"
  }
  printf tail
}'"
  "Awk program to use for encoding a file.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-awk-decode
  "busybox awk '\\
BEGIN {
  b64 = \"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/\"
}
{
  for (i=1; i<=length($0); i++) {
    c=index(b64, substr($0,i,1))
    if(c--) {
      for(b=0; b<6; b++) {
        o=o*2+int(c/32); c=(c*2)%%64
        if(++obc==8) {
          if (o) {
            printf \"%%c\", o
          } else {
            system(\"dd if=/dev/zero bs=1 count=1 2>/dev/null\")
          }
          obc=0; o=0
        }
      }
    }
  }
}'"
  "Awk program to use for decoding a file.
This string is passed to `format', so percent characters need to be doubled.")

(defconst tramp-awk-coding-test
  "test -c /dev/zero && \
od -v -t x1 -A n </dev/null && \
busybox awk '{}' </dev/null"
  "Test command for checking `tramp-awk-encode' and `tramp-awk-decode'.")

(defconst tramp-stat-marker "/////"
  "Marker in stat commands for file attributes.")

(defconst tramp-stat-quoted-marker "\\/\\/\\/\\/\\/"
  "Quoted marker in stat commands for file attributes.")

(defconst tramp-vc-registered-read-file-names
  "echo \"(\"
while read file; do
    if %s \"$file\"; then
        echo \"(\\\"$file\\\" \\\"file-exists-p\\\" t)\"
    else
        echo \"(\\\"$file\\\" \\\"file-exists-p\\\" nil)\"
    fi
    if %s \"$file\"; then
        echo \"(\\\"$file\\\" \\\"file-readable-p\\\" t)\"
    else
        echo \"(\\\"$file\\\" \\\"file-readable-p\\\" nil)\"
    fi
done
echo \")\""
  "Script to check existence of VC related files.
It must be send formatted with two strings; the tests for file
existence, and file readability.  Input shall be read via
here-document, otherwise the command could exceed maximum length
of command line.")

;; New handlers should be added here.
(defconst tramp-sh-file-name-handler-alist
  '(;; `access-file' performed by default handler.
    (add-name-to-file . tramp-sh-handle-add-name-to-file)
    ;; `byte-compiler-base-file-name' performed by default handler.
    (copy-directory . tramp-sh-handle-copy-directory)
    (copy-file . tramp-sh-handle-copy-file)
    (delete-directory . tramp-sh-handle-delete-directory)
    (delete-file . tramp-sh-handle-delete-file)
    ;; `diff-latest-backup-file' performed by default handler.
    (directory-file-name . tramp-handle-directory-file-name)
    (directory-files . tramp-handle-directory-files)
    (directory-files-and-attributes
     . tramp-sh-handle-directory-files-and-attributes)
    (dired-compress-file . tramp-sh-handle-dired-compress-file)
    (dired-uncache . tramp-handle-dired-uncache)
    (expand-file-name . tramp-sh-handle-expand-file-name)
    (file-accessible-directory-p . tramp-handle-file-accessible-directory-p)
    (file-acl . tramp-sh-handle-file-acl)
    (file-attributes . tramp-sh-handle-file-attributes)
    (file-directory-p . tramp-sh-handle-file-directory-p)
    (file-equal-p . tramp-handle-file-equal-p)
    (file-executable-p . tramp-sh-handle-file-executable-p)
    (file-exists-p . tramp-sh-handle-file-exists-p)
    (file-in-directory-p . tramp-handle-file-in-directory-p)
    (file-local-copy . tramp-sh-handle-file-local-copy)
    (file-modes . tramp-handle-file-modes)
    (file-name-all-completions . tramp-sh-handle-file-name-all-completions)
    (file-name-as-directory . tramp-handle-file-name-as-directory)
    (file-name-completion . tramp-handle-file-name-completion)
    (file-name-directory . tramp-handle-file-name-directory)
    (file-name-nondirectory . tramp-handle-file-name-nondirectory)
    ;; `file-name-sans-versions' performed by default handler.
    (file-newer-than-file-p . tramp-sh-handle-file-newer-than-file-p)
    (file-notify-add-watch . tramp-sh-handle-file-notify-add-watch)
    (file-notify-rm-watch . tramp-handle-file-notify-rm-watch)
    (file-notify-valid-p . tramp-handle-file-notify-valid-p)
    (file-ownership-preserved-p . tramp-sh-handle-file-ownership-preserved-p)
    (file-readable-p . tramp-sh-handle-file-readable-p)
    (file-regular-p . tramp-handle-file-regular-p)
    (file-remote-p . tramp-handle-file-remote-p)
    (file-selinux-context . tramp-sh-handle-file-selinux-context)
    (file-symlink-p . tramp-handle-file-symlink-p)
    (file-truename . tramp-sh-handle-file-truename)
    (file-writable-p . tramp-sh-handle-file-writable-p)
    (find-backup-file-name . tramp-handle-find-backup-file-name)
    ;; `find-file-noselect' performed by default handler.
    ;; `get-file-buffer' performed by default handler.
    (insert-directory . tramp-sh-handle-insert-directory)
    (insert-file-contents . tramp-handle-insert-file-contents)
    (load . tramp-handle-load)
    (make-auto-save-file-name . tramp-handle-make-auto-save-file-name)
    (make-directory . tramp-sh-handle-make-directory)
    (make-symbolic-link . tramp-sh-handle-make-symbolic-link)
    (process-file . tramp-sh-handle-process-file)
    (rename-file . tramp-sh-handle-rename-file)
    (set-file-acl . tramp-sh-handle-set-file-acl)
    (set-file-modes . tramp-sh-handle-set-file-modes)
    (set-file-selinux-context . tramp-sh-handle-set-file-selinux-context)
    (set-file-times . tramp-sh-handle-set-file-times)
    (set-visited-file-modtime . tramp-sh-handle-set-visited-file-modtime)
    (shell-command . tramp-handle-shell-command)
    (start-file-process . tramp-sh-handle-start-file-process)
    (substitute-in-file-name . tramp-handle-substitute-in-file-name)
    (unhandled-file-name-directory . ignore)
    (vc-registered . tramp-sh-handle-vc-registered)
    (verify-visited-file-modtime . tramp-sh-handle-verify-visited-file-modtime)
    (write-region . tramp-sh-handle-write-region))
  "Alist of handler functions.
Operations not mentioned here will be handled by the normal Emacs functions.")

;; This must be the last entry, because `identity' always matches.
;;;###tramp-autoload
(add-to-list 'tramp-foreign-file-name-handler-alist
             '(identity . tramp-sh-file-name-handler) 'append)

;;; File Name Handler Functions:

(defun tramp-sh-handle-make-symbolic-link
  (filename linkname &optional ok-if-already-exists)
  "Like `make-symbolic-link' for Tramp files.
If LINKNAME is a non-Tramp file, it is used verbatim as the target of
the symlink.  If LINKNAME is a Tramp file, only the localname component is
used as the target of the symlink.

If LINKNAME is a Tramp file and the localname component is relative, then
it is expanded first, before the localname component is taken.  Note that
this can give surprising results if the user/host for the source and
target of the symlink differ."
  (with-parsed-tramp-file-name linkname l
    (let ((ln (tramp-get-remote-ln l))
          (cwd (tramp-run-real-handler
                'file-name-directory (list l-localname))))
      (unless ln
        (tramp-error
         l 'file-error
         "Making a symbolic link.  ln(1) does not exist on the remote host."))

      ;; Do the 'confirm if exists' thing.
      (when (file-exists-p linkname)
        ;; What to do?
        (if (or (null ok-if-already-exists) ; not allowed to exist
                (and (numberp ok-if-already-exists)
                     (not (yes-or-no-p
                           (format
                            "File %s already exists; make it a link anyway? "
                            l-localname)))))
            (tramp-error
             l 'file-already-exists "File %s already exists" l-localname)
          (delete-file linkname)))

      ;; If FILENAME is a Tramp name, use just the localname component.
      (when (tramp-tramp-file-p filename)
        (setq filename
              (tramp-file-name-localname
               (tramp-dissect-file-name (expand-file-name filename)))))

      (tramp-flush-file-property l (file-name-directory l-localname))
      (tramp-flush-file-property l l-localname)

      ;; Right, they are on the same host, regardless of user, method,
      ;; etc.  We now make the link on the remote machine. This will
      ;; occur as the user that FILENAME belongs to.
      (and (tramp-send-command-and-check
            l (format "cd %s" (tramp-shell-quote-argument cwd)))
           (tramp-send-command-and-check
            l (format
               "%s -sf %s %s"
               ln
               (tramp-shell-quote-argument filename)
               ;; The command could exceed PATH_MAX, so we use
               ;; relative file names.  However, relative file names
               ;; could start with "-".  `tramp-shell-quote-argument'
               ;; does not handle this, we must do it ourselves.
               (tramp-shell-quote-argument
                (concat "./" (file-name-nondirectory l-localname)))))))))

(defun tramp-sh-handle-file-truename (filename)
  "Like `file-truename' for Tramp files."
  (format
   "%s%s"
   (with-parsed-tramp-file-name (expand-file-name filename) nil
     (tramp-make-tramp-file-name
      method user host
      (with-tramp-file-property v localname "file-truename"
        (let ((result nil))                     ; result steps in reverse order
          (tramp-message v 4 "Finding true name for `%s'" filename)
          (cond
           ;; Use GNU readlink --canonicalize-missing where available.
           ((tramp-get-remote-readlink v)
            (tramp-send-command-and-check
             v
             (format "%s --canonicalize-missing %s"
                     (tramp-get-remote-readlink v)
                     (tramp-shell-quote-argument localname)))
            (with-current-buffer (tramp-get-connection-buffer v)
              (goto-char (point-min))
              (setq result (buffer-substring (point-min) (point-at-eol)))))

           ;; Use Perl implementation.
           ((and (tramp-get-remote-perl v)
                 (tramp-get-connection-property v "perl-file-spec" nil)
                 (tramp-get-connection-property v "perl-cwd-realpath" nil))
            (tramp-maybe-send-script
             v tramp-perl-file-truename "tramp_perl_file_truename")
            (setq result
                  (tramp-send-command-and-read
                   v
                   (format "tramp_perl_file_truename %s"
                           (tramp-shell-quote-argument localname)))))

           ;; Do it yourself.
           (t (let ((steps (split-string localname "/" 'omit))
                    (thisstep nil)
                    (numchase 0)
                    ;; Don't make the following value larger than
                    ;; necessary.  People expect an error message in a
                    ;; timely fashion when something is wrong;
                    ;; otherwise they might think that Emacs is hung.
                    ;; Of course, correctness has to come first.
                    (numchase-limit 20)
                    symlink-target)
                (while (and steps (< numchase numchase-limit))
                  (setq thisstep (pop steps))
                  (tramp-message
                   v 5 "Check %s"
                   (mapconcat 'identity
                              (append '("") (reverse result) (list thisstep))
                              "/"))
                  (setq symlink-target
                        (nth 0 (file-attributes
                                (tramp-make-tramp-file-name
                                 method user host
                                 (mapconcat 'identity
                                            (append '("")
                                                    (reverse result)
                                                    (list thisstep))
                                            "/")))))
                  (cond ((string= "." thisstep)
                         (tramp-message v 5 "Ignoring step `.'"))
                        ((string= ".." thisstep)
                         (tramp-message v 5 "Processing step `..'")
                         (pop result))
                        ((stringp symlink-target)
                         ;; It's a symlink, follow it.
                         (tramp-message
                          v 5 "Follow symlink to %s" symlink-target)
                         (setq numchase (1+ numchase))
                         (when (file-name-absolute-p symlink-target)
                           (setq result nil))
                         ;; If the symlink was absolute, we'll get a
                         ;; string like "/user@host:/some/target";
                         ;; extract the "/some/target" part from it.
                         (when (tramp-tramp-file-p symlink-target)
                           (unless (tramp-equal-remote filename symlink-target)
                             (tramp-error
                              v 'file-error
                              "Symlink target `%s' on wrong host"
                              symlink-target))
                           (setq symlink-target localname))
                         (setq steps
                               (append
                                (split-string symlink-target "/" 'omit) steps)))
                        (t
                         ;; It's a file.
                         (setq result (cons thisstep result)))))
                (when (>= numchase numchase-limit)
                  (tramp-error
                   v 'file-error
                   "Maximum number (%d) of symlinks exceeded" numchase-limit))
                (setq result (reverse result))
                ;; Combine list to form string.
                (setq result
                      (if result
                          (mapconcat 'identity (cons "" result) "/")
                        "/"))
                (when (string= "" result)
                  (setq result "/")))))

          (tramp-message v 4 "True name of `%s' is `%s'" localname result)
          result))))

   ;; Preserve trailing "/".
   (if (string-equal (file-name-nondirectory filename) "") "/" "")))

;; Basic functions.

(defun tramp-sh-handle-file-exists-p (filename)
  "Like `file-exists-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-exists-p"
      (or (not (null (tramp-get-file-property
                      v localname "file-attributes-integer" nil)))
          (not (null (tramp-get-file-property
                      v localname "file-attributes-string" nil)))
          (tramp-send-command-and-check
           v
           (format
            "%s %s"
            (tramp-get-file-exists-command v)
            (tramp-shell-quote-argument localname)))))))

(defun tramp-sh-handle-file-attributes (filename &optional id-format)
  "Like `file-attributes' for Tramp files."
  (unless id-format (setq id-format 'integer))
  (ignore-errors
    ;; Don't modify `last-coding-system-used' by accident.
    (let ((last-coding-system-used last-coding-system-used))
      (with-parsed-tramp-file-name (expand-file-name filename) nil
        (with-tramp-file-property
            v localname (format "file-attributes-%s" id-format)
          (save-excursion
            (tramp-convert-file-attributes
             v
             (or
              (cond
               ((tramp-get-remote-stat v)
                (tramp-do-file-attributes-with-stat v localname id-format))
               ((tramp-get-remote-perl v)
                (tramp-do-file-attributes-with-perl v localname id-format))
               (t nil))
              ;; The scripts could fail, for example with huge file size.
              (tramp-do-file-attributes-with-ls v localname id-format)))))))))

(defun tramp-do-file-attributes-with-ls (vec localname &optional id-format)
  "Implement `file-attributes' for Tramp files using the ls(1) command."
  (let (symlinkp dirp
                 res-inode res-filemodes res-numlinks
                 res-uid res-gid res-size res-symlink-target)
    (tramp-message vec 5 "file attributes with ls: %s" localname)
    ;; We cannot send all three commands combined, it could exceed
    ;; NAME_MAX or PATH_MAX.  Happened on Mac OS X, for example.
    (when (or (tramp-send-command-and-check
               vec
               (format "%s %s"
                       (tramp-get-file-exists-command vec)
                       (tramp-shell-quote-argument localname)))
              (tramp-send-command-and-check
               vec
               (format "%s -h %s"
                       (tramp-get-test-command vec)
                       (tramp-shell-quote-argument localname))))
      (tramp-send-command
       vec
       (format "%s %s %s %s"
               (tramp-get-ls-command vec)
               (if (eq id-format 'integer) "-ildn" "-ild")
               ;; On systems which have no quoting style, file names
               ;; with special characters could fail.
               (cond
                ((tramp-get-ls-command-with-quoting-style vec)
                 "--quoting-style=c")
                ((tramp-get-ls-command-with-w-option vec)
                 "-w")
                (t ""))
               (tramp-shell-quote-argument localname)))
      ;; Parse `ls -l' output ...
      (with-current-buffer (tramp-get-buffer vec)
        (when (> (buffer-size) 0)
          (goto-char (point-min))
          ;; ... inode
          (setq res-inode
                (condition-case err
                    (read (current-buffer))
                  (invalid-read-syntax
                   (when (and (equal (cadr err)
                                     "Integer constant overflow in reader")
                              (string-match
                               "^[0-9]+\\([0-9][0-9][0-9][0-9][0-9]\\)\\'"
                               (car (cddr err))))
                     (let* ((big (read (substring (car (cddr err)) 0
                                                  (match-beginning 1))))
                            (small (read (match-string 1 (car (cddr err)))))
                            (twiddle (/ small 65536)))
                       (cons (+ big twiddle)
                             (- small (* twiddle 65536))))))))
          ;; ... file mode flags
          (setq res-filemodes (symbol-name (read (current-buffer))))
          ;; ... number links
          (setq res-numlinks (read (current-buffer)))
          ;; ... uid and gid
          (setq res-uid (read (current-buffer)))
          (setq res-gid (read (current-buffer)))
          (if (eq id-format 'integer)
              (progn
                (unless (numberp res-uid)
                  (setq res-uid tramp-unknown-id-integer))
                (unless (numberp res-gid)
                  (setq res-gid tramp-unknown-id-integer)))
            (progn
              (unless (stringp res-uid) (setq res-uid (symbol-name res-uid)))
              (unless (stringp res-gid) (setq res-gid (symbol-name res-gid)))))
          ;; ... size
          (setq res-size (read (current-buffer)))
          ;; From the file modes, figure out other stuff.
          (setq symlinkp (eq ?l (aref res-filemodes 0)))
          (setq dirp (eq ?d (aref res-filemodes 0)))
          ;; If symlink, find out file name pointed to.
          (when symlinkp
            (search-forward "-> ")
            (setq res-symlink-target
                  (if (tramp-get-ls-command-with-quoting-style vec)
                      (read (current-buffer))
                    (buffer-substring (point) (point-at-eol)))))
          ;; Return data gathered.
          (list
           ;; 0. t for directory, string (name linked to) for symbolic
           ;; link, or nil.
           (or dirp res-symlink-target)
           ;; 1. Number of links to file.
           res-numlinks
           ;; 2. File uid.
           res-uid
           ;; 3. File gid.
           res-gid
           ;; 4. Last access time, as a list of integers.  Normally
           ;; this would be in the same format as `current-time', but
           ;; the subseconds part is not currently implemented, and
           ;; (0 0) denotes an unknown time.
           ;; 5. Last modification time, likewise.
           ;; 6. Last status change time, likewise.
           '(0 0) '(0 0) '(0 0)         ;CCC how to find out?
           ;; 7. Size in bytes (-1, if number is out of range).
           res-size
           ;; 8. File modes, as a string of ten letters or dashes as in ls -l.
           res-filemodes
           ;; 9. t if file's gid would change if file were deleted and
           ;; recreated.  Will be set in `tramp-convert-file-attributes'.
           t
           ;; 10. Inode number.
           res-inode
           ;; 11. Device number.  Will be replaced by a virtual device number.
           -1))))))

(defun tramp-do-file-attributes-with-perl
  (vec localname &optional id-format)
  "Implement `file-attributes' for Tramp files using a Perl script."
  (tramp-message vec 5 "file attributes with perl: %s" localname)
  (tramp-maybe-send-script
   vec tramp-perl-file-attributes "tramp_perl_file_attributes")
  (tramp-send-command-and-read
   vec
   (format "tramp_perl_file_attributes %s %s"
           (tramp-shell-quote-argument localname) id-format)))

(defun tramp-do-file-attributes-with-stat
  (vec localname &optional id-format)
  "Implement `file-attributes' for Tramp files using stat(1) command."
  (tramp-message vec 5 "file attributes with stat: %s" localname)
  (tramp-send-command-and-read
   vec
   (format
    (concat
     ;; On Opsware, pdksh (which is the true name of ksh there)
     ;; doesn't parse correctly the sequence "((".  Therefore, we add
     ;; a space.  Apostrophes in the stat output are masked as
     ;; `tramp-stat-marker', in order to make a proper shell escape of
     ;; them in file names.
     "( (%s %s || %s -h %s) && (%s -c "
     "'((%s%%N%s) %%h %s %s %%Xe0 %%Ye0 %%Ze0 %%se0 %s%%A%s t %%ie0 -1)' "
     "%s | sed -e 's/\"/\\\\\"/g' -e 's/%s/\"/g') || echo nil)")
    (tramp-get-file-exists-command vec)
    (tramp-shell-quote-argument localname)
    (tramp-get-test-command vec)
    (tramp-shell-quote-argument localname)
    (tramp-get-remote-stat vec)
    tramp-stat-marker tramp-stat-marker
    (if (eq id-format 'integer)
        "%ue0" (concat tramp-stat-marker "%U" tramp-stat-marker))
    (if (eq id-format 'integer)
        "%ge0" (concat tramp-stat-marker "%G" tramp-stat-marker))
    tramp-stat-marker tramp-stat-marker
    (tramp-shell-quote-argument localname)
    tramp-stat-quoted-marker)))

(defun tramp-sh-handle-set-visited-file-modtime (&optional time-list)
  "Like `set-visited-file-modtime' for Tramp files."
  (unless (buffer-file-name)
    (error "Can't set-visited-file-modtime: buffer `%s' not visiting a file"
           (buffer-name)))
  (if time-list
      (tramp-run-real-handler 'set-visited-file-modtime (list time-list))
    (let ((f (buffer-file-name))
          coding-system-used)
      (with-parsed-tramp-file-name f nil
        (let* ((remote-file-name-inhibit-cache t)
               (attr (file-attributes f))
               ;; '(-1 65535) means file doesn't exists yet.
               (modtime (or (nth 5 attr) '(-1 65535))))
          (setq coding-system-used last-coding-system-used)
          ;; We use '(0 0) as a don't-know value.  See also
          ;; `tramp-do-file-attributes-with-ls'.
          (if (not (equal modtime '(0 0)))
              (tramp-run-real-handler 'set-visited-file-modtime (list modtime))
            (progn
              (tramp-send-command
               v
               (format "%s -ild %s"
                       (tramp-get-ls-command v)
                       (tramp-shell-quote-argument localname)))
              (setq attr (buffer-substring (point) (point-at-eol))))
            (tramp-set-file-property
             v localname "visited-file-modtime-ild" attr))
          (setq last-coding-system-used coding-system-used)
          nil)))))

;; This function makes the same assumption as
;; `tramp-sh-handle-set-visited-file-modtime'.
(defun tramp-sh-handle-verify-visited-file-modtime (&optional buf)
  "Like `verify-visited-file-modtime' for Tramp files.
At the time `verify-visited-file-modtime' calls this function, we
already know that the buffer is visiting a file and that
`visited-file-modtime' does not return 0.  Do not call this
function directly, unless those two cases are already taken care
of."
  (with-current-buffer (or buf (current-buffer))
    (let ((f (buffer-file-name)))
      ;; There is no file visiting the buffer, or the buffer has no
      ;; recorded last modification time, or there is no established
      ;; connection.
      (if (or (not f)
              (eq (visited-file-modtime) 0)
              (not (file-remote-p f nil 'connected)))
          t
        (with-parsed-tramp-file-name f nil
          (let* ((remote-file-name-inhibit-cache t)
                 (attr (file-attributes f))
                 (modtime (nth 5 attr))
                 (mt (visited-file-modtime)))

            (cond
             ;; File exists, and has a known modtime.
             ((and attr (not (equal modtime '(0 0))))
              (< (abs (tramp-time-diff
                       modtime
                       ;; For compatibility, deal with both the old
                       ;; (HIGH . LOW) and the new (HIGH LOW) return
                       ;; values of `visited-file-modtime'.
                       (if (atom (cdr mt))
                           (list (car mt) (cdr mt))
                         mt)))
                 2))
             ;; Modtime has the don't know value.
             (attr
              (tramp-send-command
               v
               (format "%s -ild %s"
                       (tramp-get-ls-command v)
                       (tramp-shell-quote-argument localname)))
              (with-current-buffer (tramp-get-buffer v)
                (setq attr (buffer-substring (point) (point-at-eol))))
              (equal
               attr
               (tramp-get-file-property
                v localname "visited-file-modtime-ild" "")))
             ;; If file does not exist, say it is not modified if and
             ;; only if that agrees with the buffer's record.
             (t (equal mt '(-1 65535))))))))))

(defun tramp-sh-handle-set-file-modes (filename mode)
  "Like `set-file-modes' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-file-property v localname)
    ;; FIXME: extract the proper text from chmod's stderr.
    (tramp-barf-unless-okay
     v
     (format "chmod %o %s" mode (tramp-shell-quote-argument localname))
     "Error while changing file's mode %s" filename)))

(defun tramp-sh-handle-set-file-times (filename &optional time)
  "Like `set-file-times' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (when (tramp-get-remote-touch v)
      (tramp-flush-file-property v (file-name-directory localname))
      (tramp-flush-file-property v localname)
      (let ((time (if (or (null time) (equal time '(0 0)))
                      (current-time)
                    time)))
        (tramp-send-command-and-check
         v (format
            "env TZ=UTC %s %s %s"
            (tramp-get-remote-touch v)
            (if (tramp-get-connection-property v "touch-t" nil)
                (format "-t %s" (format-time-string "%Y%m%d%H%M.%S" time t))
              "")
            (tramp-shell-quote-argument localname)))))))

(defun tramp-set-file-uid-gid (filename &optional uid gid)
  "Set the ownership for FILENAME.
If UID and GID are provided, these values are used; otherwise uid
and gid of the corresponding user is taken.  Both parameters must
be non-negative integers."
  ;; Modern Unices allow chown only for root.  So we might need
  ;; another implementation, see `dired-do-chown'.  OTOH, it is mostly
  ;; working with su(do)? when it is needed, so it shall succeed in
  ;; the majority of cases.
  ;; Don't modify `last-coding-system-used' by accident.
  (let ((last-coding-system-used last-coding-system-used))
    (if (tramp-tramp-file-p filename)
        (with-parsed-tramp-file-name filename nil
          (if (and (zerop (user-uid)) (tramp-local-host-p v))
              ;; If we are root on the local host, we can do it directly.
              (tramp-set-file-uid-gid localname uid gid)
            (let ((uid (or (and (natnump uid) uid)
                           (tramp-get-remote-uid v 'integer)))
                  (gid (or (and (natnump gid) gid)
                           (tramp-get-remote-gid v 'integer))))
              (tramp-send-command
               v (format
                  "chown %d:%d %s" uid gid
                  (tramp-shell-quote-argument localname))))))

      ;; We handle also the local part, because there doesn't exist
      ;; `set-file-uid-gid'.  On W32 "chown" might not work.  We add a
      ;; timeout for this.
      (with-timeout (5 nil)
        (let ((uid (or (and (natnump uid) uid) (tramp-get-local-uid 'integer)))
              (gid (or (and (natnump gid) gid) (tramp-get-local-gid 'integer))))
          (tramp-call-process
           nil "chown" nil nil nil
           (format "%d:%d" uid gid) (tramp-shell-quote-argument filename)))))))

(defun tramp-remote-selinux-p (vec)
  "Check, whether SELINUX is enabled on the remote host."
  (with-tramp-connection-property (tramp-get-connection-process vec) "selinux-p"
    (tramp-send-command-and-check vec "selinuxenabled")))

(defun tramp-sh-handle-file-selinux-context (filename)
  "Like `file-selinux-context' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-selinux-context"
      (let ((context '(nil nil nil nil))
            (regexp (concat "\\([a-z0-9_]+\\):" "\\([a-z0-9_]+\\):"
                            "\\([a-z0-9_]+\\):" "\\([a-z0-9_]+\\)")))
        (when (and (tramp-remote-selinux-p v)
                   (tramp-send-command-and-check
                    v (format
                       "%s -d -Z %s"
                       (tramp-get-ls-command v)
                       (tramp-shell-quote-argument localname))))
          (with-current-buffer (tramp-get-connection-buffer v)
            (goto-char (point-min))
            (when (re-search-forward regexp (point-at-eol) t)
              (setq context (list (match-string 1) (match-string 2)
                                  (match-string 3) (match-string 4))))))
        ;; Return the context.
        context))))

(defun tramp-sh-handle-set-file-selinux-context (filename context)
  "Like `set-file-selinux-context' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (when (and (consp context)
               (tramp-remote-selinux-p v))
      (let ((user (and (stringp (nth 0 context)) (nth 0 context)))
            (role (and (stringp (nth 1 context)) (nth 1 context)))
            (type (and (stringp (nth 2 context)) (nth 2 context)))
            (range (and (stringp (nth 3 context)) (nth 3 context))))
        (when (tramp-send-command-and-check
               v (format "chcon %s %s %s %s %s"
                         (if user (format "--user=%s" user) "")
                         (if role (format "--role=%s" role) "")
                         (if type (format "--type=%s" type) "")
                         (if range (format "--range=%s" range) "")
                       (tramp-shell-quote-argument localname)))
          (if (and user role type range)
              (tramp-set-file-property
               v localname "file-selinux-context" context)
            (tramp-set-file-property
             v localname "file-selinux-context" 'undef))
          t)))))

(defun tramp-remote-acl-p (vec)
  "Check, whether ACL is enabled on the remote host."
  (with-tramp-connection-property (tramp-get-connection-process vec) "acl-p"
    (tramp-send-command-and-check vec "getfacl /")))

(defun tramp-sh-handle-file-acl (filename)
  "Like `file-acl' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-acl"
      (when (and (tramp-remote-acl-p v)
                 (tramp-send-command-and-check
                  v (format
                     "getfacl -ac %s"
                     (tramp-shell-quote-argument localname))))
        (with-current-buffer (tramp-get-connection-buffer v)
          (goto-char (point-max))
          (delete-blank-lines)
          (when (> (point-max) (point-min))
            (substring-no-properties (buffer-string))))))))

(defun tramp-sh-handle-set-file-acl (filename acl-string)
  "Like `set-file-acl' for Tramp files."
  (with-parsed-tramp-file-name (expand-file-name filename) nil
    (if (and (stringp acl-string) (tramp-remote-acl-p v)
             (progn
               (tramp-send-command
                v (format "setfacl --set-file=- %s <<'%s'\n%s\n%s\n"
                          (tramp-shell-quote-argument localname)
                          tramp-end-of-heredoc
                          acl-string
                          tramp-end-of-heredoc))
               (tramp-send-command-and-check v nil)))
        ;; Success.
        (progn
          (tramp-set-file-property v localname "file-acl" acl-string)
          t)
      ;; In case of errors, we return nil.
      (tramp-set-file-property v localname "file-acl-string" 'undef)
      nil)))

;; Simple functions using the `test' command.

(defun tramp-sh-handle-file-executable-p (filename)
  "Like `file-executable-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-executable-p"
      ;; Examine `file-attributes' cache to see if request can be
      ;; satisfied without remote operation.
      (or (tramp-check-cached-permissions v ?x)
          (tramp-run-test "-x" filename)))))

(defun tramp-sh-handle-file-readable-p (filename)
  "Like `file-readable-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-readable-p"
      ;; Examine `file-attributes' cache to see if request can be
      ;; satisfied without remote operation.
      (or (tramp-check-cached-permissions v ?r)
          (tramp-run-test "-r" filename)))))

;; When the remote shell is started, it looks for a shell which groks
;; tilde expansion.  Here, we assume that all shells which grok tilde
;; expansion will also provide a `test' command which groks `-nt' (for
;; newer than).  If this breaks, tell me about it and I'll try to do
;; something smarter about it.
(defun tramp-sh-handle-file-newer-than-file-p (file1 file2)
  "Like `file-newer-than-file-p' for Tramp files."
  (cond ((not (file-exists-p file1))
         nil)
        ((not (file-exists-p file2))
         t)
        ;; We are sure both files exist at this point.
        (t
         (save-excursion
           ;; We try to get the mtime of both files.  If they are not
           ;; equal to the "dont-know" value, then we subtract the times
           ;; and obtain the result.
           (let ((fa1 (file-attributes file1))
                 (fa2 (file-attributes file2)))
             (if (and (not (equal (nth 5 fa1) '(0 0)))
                      (not (equal (nth 5 fa2) '(0 0))))
                 (> 0 (tramp-time-diff (nth 5 fa2) (nth 5 fa1)))
               ;; If one of them is the dont-know value, then we can
               ;; still try to run a shell command on the remote host.
               ;; However, this only works if both files are Tramp
               ;; files and both have the same method, same user, same
               ;; host.
               (unless (tramp-equal-remote file1 file2)
                 (with-parsed-tramp-file-name
                     (if (tramp-tramp-file-p file1) file1 file2) nil
                   (tramp-error
                    v 'file-error
                    "Files %s and %s must have same method, user, host"
                    file1 file2)))
               (with-parsed-tramp-file-name file1 nil
                 (tramp-run-test2
                  (tramp-get-test-nt-command v) file1 file2))))))))

;; Functions implemented using the basic functions above.

(defun tramp-sh-handle-file-directory-p (filename)
  "Like `file-directory-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    ;; `file-directory-p' is used as predicate for file name completion.
    ;; Sometimes, when a connection is not established yet, it is
    ;; desirable to return t immediately for "/method:foo:".  It can
    ;; be expected that this is always a directory.
    (or (zerop (length localname))
        (with-tramp-file-property v localname "file-directory-p"
          (tramp-run-test "-d" filename)))))

(defun tramp-sh-handle-file-writable-p (filename)
  "Like `file-writable-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-writable-p"
      (if (file-exists-p filename)
          ;; Examine `file-attributes' cache to see if request can be
          ;; satisfied without remote operation.
          (or (tramp-check-cached-permissions v ?w)
              (tramp-run-test "-w" filename))
        ;; If file doesn't exist, check if directory is writable.
        (and (tramp-run-test "-d" (file-name-directory filename))
             (tramp-run-test "-w" (file-name-directory filename)))))))

(defun tramp-sh-handle-file-ownership-preserved-p (filename &optional group)
  "Like `file-ownership-preserved-p' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (with-tramp-file-property v localname "file-ownership-preserved-p"
      (let ((attributes (file-attributes filename)))
        ;; Return t if the file doesn't exist, since it's true that no
        ;; information would be lost by an (attempted) delete and create.
        (or (null attributes)
            (and
             (= (nth 2 attributes) (tramp-get-remote-uid v 'integer))
             (or (not group)
                 (= (nth 3 attributes) (tramp-get-remote-gid v 'integer)))))))))

;; Directory listings.

(defun tramp-sh-handle-directory-files-and-attributes
  (directory &optional full match nosort id-format)
  "Like `directory-files-and-attributes' for Tramp files."
  (unless id-format (setq id-format 'integer))
  (when (file-directory-p directory)
    (setq directory (expand-file-name directory))
    (let* ((temp
            (copy-tree
             (with-parsed-tramp-file-name directory nil
               (with-tramp-file-property
                   v localname
                   (format "directory-files-and-attributes-%s" id-format)
                 (save-excursion
                   (mapcar
                    (lambda (x)
                      (cons (car x)
                            (tramp-convert-file-attributes v (cdr x))))
                    (or
                     (cond
                      ((tramp-get-remote-stat v)
                       (tramp-do-directory-files-and-attributes-with-stat
                        v localname id-format))
                      ((tramp-get-remote-perl v)
                       (tramp-do-directory-files-and-attributes-with-perl
                        v localname id-format))
                      (t nil)))))))))
           result item)

      (while temp
        (setq item (pop temp))
        (when (or (null match) (string-match match (car item)))
          (when full
            (setcar item (expand-file-name (car item) directory)))
          (push item result)))

      (or (if nosort
              result
            (sort result (lambda (x y) (string< (car x) (car y)))))
          ;; The scripts could fail, for example with huge file size.
          (tramp-handle-directory-files-and-attributes
           directory full match nosort id-format)))))

(defun tramp-do-directory-files-and-attributes-with-perl
  (vec localname &optional id-format)
  "Implement `directory-files-and-attributes' for Tramp files using a Perl script."
  (tramp-message vec 5 "directory-files-and-attributes with perl: %s" localname)
  (tramp-maybe-send-script
   vec tramp-perl-directory-files-and-attributes
   "tramp_perl_directory_files_and_attributes")
  (let ((object
         (tramp-send-command-and-read
          vec
          (format "tramp_perl_directory_files_and_attributes %s %s"
                  (tramp-shell-quote-argument localname) id-format))))
    (when (stringp object) (tramp-error vec 'file-error object))
    object))

(defun tramp-do-directory-files-and-attributes-with-stat
  (vec localname &optional id-format)
  "Implement `directory-files-and-attributes' for Tramp files using stat(1) command."
  (tramp-message vec 5 "directory-files-and-attributes with stat: %s" localname)
  (tramp-send-command-and-read
   vec
   (format
    (concat
     ;; We must care about file names with spaces, or starting with
     ;; "-"; this would confuse xargs.  "ls -aQ" might be a solution,
     ;; but it does not work on all remote systems.  Apostrophes in
     ;; the stat output are masked as `tramp-stat-marker', in order to
     ;; make a proper shell escape of them in file names.
     "cd %s && echo \"(\"; (%s %s -a | "
     "xargs %s -c "
     "'(%s%%n%s (%s%%N%s) %%h %s %s %%Xe0 %%Ye0 %%Ze0 %%se0 %s%%A%s t %%ie0 -1)' "
     "-- 2>/dev/null | sed -e 's/\"/\\\\\"/g' -e 's/%s/\"/g'); echo \")\"")
    (tramp-shell-quote-argument localname)
    (tramp-get-ls-command vec)
    ;; On systems which have no quoting style, file names with special
    ;; characters could fail.
    (cond
     ((tramp-get-ls-command-with-quoting-style vec)
      "--quoting-style=shell")
     ((tramp-get-ls-command-with-w-option vec)
      "-w")
     (t ""))
    (tramp-get-remote-stat vec)
    tramp-stat-marker tramp-stat-marker
    tramp-stat-marker tramp-stat-marker
    (if (eq id-format 'integer)
        "%ue0" (concat tramp-stat-marker "%U" tramp-stat-marker))
    (if (eq id-format 'integer)
        "%ge0" (concat tramp-stat-marker "%G" tramp-stat-marker))
    tramp-stat-marker tramp-stat-marker
    tramp-stat-quoted-marker)))

;; This function should return "foo/" for directories and "bar" for
;; files.
(defun tramp-sh-handle-file-name-all-completions (filename directory)
  "Like `file-name-all-completions' for Tramp files."
  (unless (save-match-data (string-match "/" filename))
    (all-completions
     filename
     (with-parsed-tramp-file-name (expand-file-name directory) nil
       (with-tramp-file-property v localname "file-name-all-completions"
         (let (result)
           ;; Get a list of directories and files, including reliably
           ;; tagging the directories with a trailing "/".  Because I
           ;; rock.  --daniel@danann.net
           (tramp-send-command
            v
            (if (tramp-get-remote-perl v)
                (progn
                  (tramp-maybe-send-script
                   v tramp-perl-file-name-all-completions
                   "tramp_perl_file_name_all_completions")
                  (format "tramp_perl_file_name_all_completions %s"
                          (tramp-shell-quote-argument localname)))

              (format (concat
                       "(cd %s 2>&1 && %s -a 2>/dev/null"
                       " | while IFS= read f; do"
                       " if %s -d \"$f\" 2>/dev/null;"
                       " then \\echo \"$f/\"; else \\echo \"$f\"; fi; done"
                       " && \\echo ok) || \\echo fail")
                      (tramp-shell-quote-argument localname)
                      (tramp-get-ls-command v)
                      (tramp-get-test-command v))))

           ;; Now grab the output.
           (with-current-buffer (tramp-get-buffer v)
             (goto-char (point-max))

             ;; Check result code, found in last line of output.
             (forward-line -1)
             (if (looking-at "^fail$")
                 (progn
                   ;; Grab error message from line before last line
                   ;; (it was put there by `cd 2>&1').
                   (forward-line -1)
                   (tramp-error
                    v 'file-error
                    "tramp-sh-handle-file-name-all-completions: %s"
                    (buffer-substring (point) (point-at-eol))))
               ;; For peace of mind, if buffer doesn't end in `fail'
               ;; then it should end in `ok'.  If neither are in the
               ;; buffer something went seriously wrong on the remote
               ;; side.
               (unless (looking-at "^ok$")
                 (tramp-error
                  v 'file-error
                  "\
tramp-sh-handle-file-name-all-completions: internal error accessing `%s': `%s'"
                  (tramp-shell-quote-argument localname) (buffer-string))))

             (while (zerop (forward-line -1))
               (push (buffer-substring (point) (point-at-eol)) result)))
           result))))))

;; cp, mv and ln

(defun tramp-sh-handle-add-name-to-file
  (filename newname &optional ok-if-already-exists)
  "Like `add-name-to-file' for Tramp files."
  (unless (tramp-equal-remote filename newname)
    (with-parsed-tramp-file-name
        (if (tramp-tramp-file-p filename) filename newname) nil
      (tramp-error
       v 'file-error
       "add-name-to-file: %s"
       "only implemented for same method, same user, same host")))
  (with-parsed-tramp-file-name filename v1
    (with-parsed-tramp-file-name newname v2
      (let ((ln (when v1 (tramp-get-remote-ln v1))))
        (when (and (numberp ok-if-already-exists)
                   (file-exists-p newname)
                   (yes-or-no-p
                    (format
                     "File %s already exists; make it a new name anyway? "
                     newname)))
          (tramp-error
           v2 'file-error "add-name-to-file: file %s already exists" newname))
        (when ok-if-already-exists (setq ln (concat ln " -f")))
        (tramp-flush-file-property v2 (file-name-directory v2-localname))
        (tramp-flush-file-property v2 v2-localname)
        (tramp-barf-unless-okay
         v1
         (format "%s %s %s" ln
                 (tramp-shell-quote-argument v1-localname)
                 (tramp-shell-quote-argument v2-localname))
         "error with add-name-to-file, see buffer `%s' for details"
         (buffer-name))))))

(defun tramp-sh-handle-copy-file
  (filename newname &optional ok-if-already-exists keep-date
            preserve-uid-gid preserve-extended-attributes)
  "Like `copy-file' for Tramp files."
  (setq filename (expand-file-name filename))
  (setq newname (expand-file-name newname))
  (cond
   ;; At least one file a Tramp file?
   ((or (tramp-tramp-file-p filename)
        (tramp-tramp-file-p newname))
    (tramp-do-copy-or-rename-file
     'copy filename newname ok-if-already-exists keep-date
     preserve-uid-gid preserve-extended-attributes))
   ;; Compat section.  PRESERVE-EXTENDED-ATTRIBUTES has been
   ;; introduced with Emacs 24.1 (as PRESERVE-SELINUX-CONTEXT), and
   ;; renamed in Emacs 24.3.
   (preserve-extended-attributes
    (tramp-run-real-handler
     'copy-file
     (list filename newname ok-if-already-exists keep-date
           preserve-uid-gid preserve-extended-attributes)))
   (t
    (tramp-run-real-handler
     'copy-file
     (list filename newname ok-if-already-exists keep-date preserve-uid-gid)))))

(defun tramp-sh-handle-copy-directory
  (dirname newname &optional keep-date parents copy-contents)
  "Like `copy-directory' for Tramp files."
  (let ((t1 (tramp-tramp-file-p dirname))
        (t2 (tramp-tramp-file-p newname)))
    (with-parsed-tramp-file-name (if t1 dirname newname) nil
      (if (and (not copy-contents)
               (tramp-get-method-parameter v 'tramp-copy-recursive)
               ;; When DIRNAME and NEWNAME are remote, they must have
               ;; the same method.
               (or (null t1) (null t2)
                   (string-equal
                    (tramp-file-name-method (tramp-dissect-file-name dirname))
                    (tramp-file-name-method
                     (tramp-dissect-file-name newname)))))
          ;; scp or rsync DTRT.
          (progn
            (setq dirname (directory-file-name (expand-file-name dirname))
                  newname (directory-file-name (expand-file-name newname)))
            (if (and (file-directory-p newname)
                     (not (string-equal (file-name-nondirectory dirname)
                                        (file-name-nondirectory newname))))
                (setq newname
                      (expand-file-name
                       (file-name-nondirectory dirname) newname)))
            (if (not (file-directory-p (file-name-directory newname)))
                (make-directory (file-name-directory newname) parents))
            (tramp-do-copy-or-rename-file-out-of-band
             'copy dirname newname keep-date))
        ;; We must do it file-wise.
        (tramp-run-real-handler
         'copy-directory
         (if copy-contents
             (list dirname newname keep-date parents copy-contents)
           (list dirname newname keep-date parents))))

      ;; When newname did exist, we have wrong cached values.
      (when t2
        (with-parsed-tramp-file-name newname nil
          (tramp-flush-file-property v (file-name-directory localname))
          (tramp-flush-file-property v localname))))))

(defun tramp-sh-handle-rename-file
  (filename newname &optional ok-if-already-exists)
  "Like `rename-file' for Tramp files."
  ;; Check if both files are local -- invoke normal rename-file.
  ;; Otherwise, use Tramp from local system.
  (setq filename (expand-file-name filename))
  (setq newname (expand-file-name newname))
  ;; At least one file a Tramp file?
  (if (or (tramp-tramp-file-p filename)
          (tramp-tramp-file-p newname))
      (tramp-do-copy-or-rename-file
       'rename filename newname ok-if-already-exists
       'keep-time 'preserve-uid-gid)
    (tramp-run-real-handler
     'rename-file (list filename newname ok-if-already-exists))))

(defun tramp-do-copy-or-rename-file
  (op filename newname &optional ok-if-already-exists keep-date
      preserve-uid-gid preserve-extended-attributes)
  "Copy or rename a remote file.
OP must be `copy' or `rename' and indicates the operation to perform.
FILENAME specifies the file to copy or rename, NEWNAME is the name of
the new file (for copy) or the new name of the file (for rename).
OK-IF-ALREADY-EXISTS means don't barf if NEWNAME exists already.
KEEP-DATE means to make sure that NEWNAME has the same timestamp
as FILENAME.  PRESERVE-UID-GID, when non-nil, instructs to keep
the uid and gid if both files are on the same host.
PRESERVE-EXTENDED-ATTRIBUTES activates selinux and acl commands.

This function is invoked by `tramp-sh-handle-copy-file' and
`tramp-sh-handle-rename-file'.  It is an error if OP is neither
of `copy' and `rename'.  FILENAME and NEWNAME must be absolute
file names."
  (unless (memq op '(copy rename))
    (error "Unknown operation `%s', must be `copy' or `rename'" op))
  (let ((t1 (tramp-tramp-file-p filename))
        (t2 (tramp-tramp-file-p newname))
        (length (nth 7 (file-attributes (file-truename filename))))
        (attributes (and preserve-extended-attributes
                         (apply 'file-extended-attributes (list filename)))))

    (with-parsed-tramp-file-name (if t1 filename newname) nil
      (when (and (not ok-if-already-exists) (file-exists-p newname))
        (tramp-error
         v 'file-already-exists "File %s already exists" newname))

      (with-tramp-progress-reporter
          v 0 (format "%s %s to %s"
                      (if (eq op 'copy) "Copying" "Renaming")
                      filename newname)

        (cond
         ;; Both are Tramp files.
         ((and t1 t2)
          (with-parsed-tramp-file-name filename v1
            (with-parsed-tramp-file-name newname v2
              (cond
               ;; Shortcut: if method, host, user are the same for
               ;; both files, we invoke `cp' or `mv' on the remote
               ;; host directly.
               ((tramp-equal-remote filename newname)
                (tramp-do-copy-or-rename-file-directly
                 op filename newname
                 ok-if-already-exists keep-date preserve-uid-gid))

               ;; Try out-of-band operation.
               ((and
                 (tramp-method-out-of-band-p v1 length)
                 (tramp-method-out-of-band-p v2 length))
                (tramp-do-copy-or-rename-file-out-of-band
                 op filename newname keep-date))

               ;; No shortcut was possible.  So we copy the file
               ;; first.  If the operation was `rename', we go back
               ;; and delete the original file (if the copy was
               ;; successful).  The approach is simple-minded: we
               ;; create a new buffer, insert the contents of the
               ;; source file into it, then write out the buffer to
               ;; the target file.  The advantage is that it doesn't
               ;; matter which file name handlers are used for the
               ;; source and target file.
               (t
                (tramp-do-copy-or-rename-file-via-buffer
                 op filename newname keep-date))))))

         ;; One file is a Tramp file, the other one is local.
         ((or t1 t2)
          (cond
           ;; Fast track on local machine.
           ((tramp-local-host-p v)
            (tramp-do-copy-or-rename-file-directly
             op filename newname
             ok-if-already-exists keep-date preserve-uid-gid))

           ;; If the Tramp file has an out-of-band method, the
           ;; corresponding copy-program can be invoked.
           ((tramp-method-out-of-band-p v length)
            (tramp-do-copy-or-rename-file-out-of-band
             op filename newname keep-date))

           ;; Use the inline method via a Tramp buffer.
           (t (tramp-do-copy-or-rename-file-via-buffer
               op filename newname keep-date))))

         (t
          ;; One of them must be a Tramp file.
          (error "Tramp implementation says this cannot happen")))

        ;; Handle `preserve-extended-attributes'.  We ignore possible
        ;; errors, because ACL strings could be incompatible.
        (when attributes
          (ignore-errors
            (apply 'set-file-extended-attributes (list newname attributes))))

        ;; In case of `rename', we must flush the cache of the source file.
        (when (and t1 (eq op 'rename))
          (with-parsed-tramp-file-name filename v1
            (tramp-flush-file-property v1 (file-name-directory v1-localname))
            (tramp-flush-file-property v1 v1-localname)))

        ;; When newname did exist, we have wrong cached values.
        (when t2
          (with-parsed-tramp-file-name newname v2
            (tramp-flush-file-property v2 (file-name-directory v2-localname))
            (tramp-flush-file-property v2 v2-localname)))))))

(defun tramp-do-copy-or-rename-file-via-buffer (op filename newname keep-date)
  "Use an Emacs buffer to copy or rename a file.
First arg OP is either `copy' or `rename' and indicates the operation.
FILENAME is the source file, NEWNAME the target file.
KEEP-DATE is non-nil if NEWNAME should have the same timestamp as FILENAME."
  ;; We must disable multibyte, because binary data shall not be
  ;; converted.  We don't want the target file to be compressed, so we
  ;; let-bind `jka-compr-inhibit' to t.  `epa-file-handler' shall not
  ;; be called either.  We remove `tramp-file-name-handler' from
  ;; `inhibit-file-name-handlers'; otherwise the file name handler for
  ;; `insert-file-contents' might be deactivated in some corner cases.
  (let ((coding-system-for-read 'binary)
        (coding-system-for-write 'binary)
        (jka-compr-inhibit t)
        (inhibit-file-name-operation 'write-region)
        (inhibit-file-name-handlers
         (cons 'epa-file-handler
               (remq 'tramp-file-name-handler inhibit-file-name-handlers))))
    (with-temp-file newname
      (set-buffer-multibyte nil)
      (insert-file-contents-literally filename)))
  ;; KEEP-DATE handling.
  (when keep-date (set-file-times newname (nth 5 (file-attributes filename))))
  ;; Set the mode.
  (set-file-modes newname (tramp-default-file-modes filename))
  ;; If the operation was `rename', delete the original file.
  (unless (eq op 'copy) (delete-file filename)))

(defun tramp-do-copy-or-rename-file-directly
 (op filename newname ok-if-already-exists keep-date preserve-uid-gid)
  "Invokes `cp' or `mv' on the remote system.
OP must be one of `copy' or `rename', indicating `cp' or `mv',
respectively.  FILENAME specifies the file to copy or rename,
NEWNAME is the name of the new file (for copy) or the new name of
the file (for rename).  Both files must reside on the same host.
KEEP-DATE means to make sure that NEWNAME has the same timestamp
as FILENAME.  PRESERVE-UID-GID, when non-nil, instructs to keep
the uid and gid from FILENAME."
  (let ((t1 (tramp-tramp-file-p filename))
        (t2 (tramp-tramp-file-p newname))
        (file-times (nth 5 (file-attributes filename)))
        (file-modes (tramp-default-file-modes filename)))
    (with-parsed-tramp-file-name (if t1 filename newname) nil
      (let* ((cmd (cond ((and (eq op 'copy) preserve-uid-gid) "cp -f -p")
                        ((eq op 'copy) "cp -f")
                        ((eq op 'rename) "mv -f")
                        (t (tramp-error
                            v 'file-error
                            "Unknown operation `%s', must be `copy' or `rename'"
                            op))))
             (localname1
              (if t1
                  (file-remote-p filename 'localname)
                filename))
             (localname2
              (if t2
                  (file-remote-p newname 'localname)
                newname))
             (prefix (file-remote-p (if t1 filename newname)))
             cmd-result)

        (cond
         ;; Both files are on a remote host, with same user.
         ((and t1 t2)
          (setq cmd-result
                (tramp-send-command-and-check
                 v (format "%s %s %s" cmd
                           (tramp-shell-quote-argument localname1)
                           (tramp-shell-quote-argument localname2))))
          (with-current-buffer (tramp-get-buffer v)
            (goto-char (point-min))
            (unless
                (or
                 (and keep-date
                      ;; Mask cp -f error.
                      (re-search-forward
                       tramp-operation-not-permitted-regexp nil t))
                 cmd-result)
              (tramp-error-with-buffer
               nil v 'file-error
               "Copying directly failed, see buffer `%s' for details."
               (buffer-name)))))

         ;; We are on the local host.
         ((or t1 t2)
          (cond
           ;; We can do it directly.
           ((let (file-name-handler-alist)
              (and (file-readable-p localname1)
                   ;; No sticky bit when renaming.
                   (or (eq op 'copy)
                       (zerop
                        (logand
                         (file-modes (file-name-directory localname1))
                         (string-to-number "1000" 8))))
                   (file-writable-p (file-name-directory localname2))
                   (or (file-directory-p localname2)
                       (file-writable-p localname2))))
            (if (eq op 'copy)
                (copy-file
                 localname1 localname2 ok-if-already-exists
                 keep-date preserve-uid-gid)
              (tramp-run-real-handler
               'rename-file (list localname1 localname2 ok-if-already-exists))))

           ;; We can do it directly with `tramp-send-command'
           ((and (file-readable-p (concat prefix localname1))
                 (file-writable-p
                  (file-name-directory (concat prefix localname2)))
                 (or (file-directory-p (concat prefix localname2))
                     (file-writable-p (concat prefix localname2))))
            (tramp-do-copy-or-rename-file-directly
             op (concat prefix localname1) (concat prefix localname2)
             ok-if-already-exists keep-date t)
            ;; We must change the ownership to the local user.
            (tramp-set-file-uid-gid
             (concat prefix localname2)
             (tramp-get-local-uid 'integer)
             (tramp-get-local-gid 'integer)))

           ;; We need a temporary file in between.
           (t
            ;; Create the temporary file.
            (let ((tmpfile (tramp-compat-make-temp-file localname1)))
              (unwind-protect
                  (progn
                    (cond
                     (t1
                      (tramp-barf-unless-okay
                       v (format
                          "%s %s %s" cmd
                          (tramp-shell-quote-argument localname1)
                          (tramp-shell-quote-argument tmpfile))
                       "Copying directly failed, see buffer `%s' for details."
                       (tramp-get-buffer v))
                      ;; We must change the ownership as remote user.
                      ;; Since this does not work reliable, we also
                      ;; give read permissions.
                      (set-file-modes
                       (concat prefix tmpfile) (string-to-number "0777" 8))
                      (tramp-set-file-uid-gid
                       (concat prefix tmpfile)
                       (tramp-get-local-uid 'integer)
                       (tramp-get-local-gid 'integer)))
                     (t2
                      (if (eq op 'copy)
                          (copy-file
                           localname1 tmpfile t
                           keep-date preserve-uid-gid)
                        (tramp-run-real-handler
                         'rename-file
                         (list localname1 tmpfile t)))
                      ;; We must change the ownership as local user.
                      ;; Since this does not work reliable, we also
                      ;; give read permissions.
                      (set-file-modes tmpfile (string-to-number "0777" 8))
                      (tramp-set-file-uid-gid
                       tmpfile
                       (tramp-get-remote-uid v 'integer)
                       (tramp-get-remote-gid v 'integer))))

                    ;; Move the temporary file to its destination.
                    (cond
                     (t2
                      (tramp-barf-unless-okay
                       v (format
                          "cp -f -p %s %s"
                          (tramp-shell-quote-argument tmpfile)
                          (tramp-shell-quote-argument localname2))
                       "Copying directly failed, see buffer `%s' for details."
                       (tramp-get-buffer v)))
                     (t1
                      (tramp-run-real-handler
                       'rename-file
                       (list tmpfile localname2 ok-if-already-exists)))))

                ;; Save exit.
                (ignore-errors (delete-file tmpfile)))))))))

      ;; Set the time and mode. Mask possible errors.
      (ignore-errors
          (when keep-date
            (set-file-times newname file-times)
            (set-file-modes newname file-modes))))))

(defun tramp-do-copy-or-rename-file-out-of-band (op filename newname keep-date)
  "Invoke `scp' program to copy.
The method used must be an out-of-band method."
  (let* ((t1 (tramp-tramp-file-p filename))
         (t2 (tramp-tramp-file-p newname))
         (orig-vec (tramp-dissect-file-name (if t1 filename newname)))
         copy-program copy-args copy-env copy-keep-date port listener spec
         options source target remote-copy-program remote-copy-args)

    (with-parsed-tramp-file-name (if t1 filename newname) nil
      (if (and t1 t2)

          ;; Both are Tramp files.  We shall optimize it when the
          ;; methods for FILENAME and NEWNAME are the same.
          (let* ((dir-flag (file-directory-p filename))
                 (tmpfile (tramp-compat-make-temp-file localname dir-flag)))
            (if dir-flag
                (setq tmpfile
                      (expand-file-name
                       (file-name-nondirectory newname) tmpfile)))
            (unwind-protect
                (progn
                  (tramp-do-copy-or-rename-file-out-of-band
                   op filename tmpfile keep-date)
                  (tramp-do-copy-or-rename-file-out-of-band
                   'rename tmpfile newname keep-date))
              ;; Save exit.
              (ignore-errors
                (if dir-flag
                    (delete-directory
                     (expand-file-name ".." tmpfile) 'recursive)
                  (delete-file tmpfile)))))

        ;; Set variables for computing the prompt for reading
        ;; password.
        (setq tramp-current-method (tramp-file-name-method v)
              tramp-current-user (or (tramp-file-name-user v)
                                     (tramp-get-connection-property
                                      v "login-as" nil))
              tramp-current-host (tramp-file-name-real-host v))

        ;; Expand hops.  Might be necessary for gateway methods.
        (setq v (car (tramp-compute-multi-hops v)))
        (aset v 3 localname)

        ;; Check which ones of source and target are Tramp files.
        (setq source (if t1
                         (tramp-make-copy-program-file-name v)
                       (shell-quote-argument filename))
          target (if t2
                     (tramp-make-copy-program-file-name v)
                   (shell-quote-argument
                    (funcall
                      (if (and (file-directory-p filename)
                               (string-equal
                                (file-name-nondirectory filename)
                                (file-name-nondirectory newname)))
                          'file-name-directory
                        'identity)
                     newname))))

        ;; Check for host and port number.  We cannot use
        ;; `tramp-file-name-port', because this returns also
        ;; `tramp-default-port', which might clash with settings in
        ;; "~/.ssh/config".
        (setq host (tramp-file-name-host v)
              port "")
        (when (string-match tramp-host-with-port-regexp host)
          (setq port (string-to-number (match-string 2 host))
                host (string-to-number (match-string 1 host))))

        ;; Check for user.  There might be an interactive setting.
        (setq user (or (tramp-file-name-user v)
                       (tramp-get-connection-property v "login-as" nil)))

        ;; Check for listener port.
        (when (tramp-get-method-parameter v 'tramp-remote-copy-args)
          (setq listener (number-to-string (+ 50000 (random 10000))))
          (while
              (zerop (tramp-call-process v "nc" nil nil nil "-z" host listener))
            (setq listener (number-to-string (+ 50000 (random 10000))))))

        ;; Compose copy command.
        (setq host (or host "")
              user (or user "")
              port (or port "")
              spec (format-spec-make
                    ?t (tramp-get-connection-property
                        (tramp-get-connection-process v) "temp-file" ""))
              options (format-spec (tramp-ssh-controlmaster-options v) spec)
              spec (format-spec-make
                    ?h host ?u user ?p port ?r listener ?c options
                    ?k (if keep-date " " ""))
              copy-program (tramp-get-method-parameter v 'tramp-copy-program)
              copy-keep-date (tramp-get-method-parameter
                              v 'tramp-copy-keep-date)

              copy-args
              (delete
               ;; " " has either been a replacement of "%k" (when
               ;; keep-date argument is non-nil), or a replacement
               ;; for the whole keep-date sublist.
               " "
               (dolist
                   (x (tramp-get-method-parameter v 'tramp-copy-args) copy-args)
                 (setq copy-args
                       (append
                        copy-args
                        (let ((y (mapcar (lambda (z) (format-spec z spec)) x)))
                          (if (member "" y) '(" ") y))))))

              copy-env
              (delq
               nil
               (mapcar
                (lambda (x)
                  (setq x (mapcar (lambda (y) (format-spec y spec)) x))
                  (unless (member "" x) (mapconcat 'identity x " ")))
                (tramp-get-method-parameter v 'tramp-copy-env)))

              remote-copy-program
              (tramp-get-method-parameter v 'tramp-remote-copy-program))

        (dolist (x (tramp-get-method-parameter v 'tramp-remote-copy-args))
          (setq remote-copy-args
                (append
                 remote-copy-args
                 (let ((y (mapcar (lambda (z) (format-spec z spec)) x)))
                   (if (member "" y) '(" ") y)))))

        ;; Check for local copy program.
        (unless (executable-find copy-program)
          (tramp-error
           v 'file-error "Cannot find local copy program: %s" copy-program))

        ;; Install listener on the remote side.  The prompt must be
        ;; consumed later on, when the process does not listen anymore.
        (when remote-copy-program
          (unless (with-tramp-connection-property
                      v (concat "remote-copy-program-" remote-copy-program)
                    (tramp-find-executable
                     v remote-copy-program (tramp-get-remote-path v)))
            (tramp-error
             v 'file-error
             "Cannot find remote listener: %s" remote-copy-program))
          (setq remote-copy-program
                (mapconcat
                 'identity
                 (append
                  (list remote-copy-program) remote-copy-args
                  (list (if t1 (concat "<" source) (concat ">" target)) "&"))
                 " "))
          (tramp-send-command v remote-copy-program)
          (with-timeout
              (60 (tramp-error
                   v 'file-error
                   "Listener process not running on remote host: `%s'"
                   remote-copy-program))
            (tramp-send-command v (format "netstat -l | grep -q :%s" listener))
            (while (not (tramp-send-command-and-check v nil))
              (tramp-send-command
               v (format "netstat -l | grep -q :%s" listener)))))

        (with-temp-buffer
          (unwind-protect
              ;; The default directory must be remote.
              (let ((default-directory
                      (file-name-directory (if t1 filename newname)))
                    (process-environment (copy-sequence process-environment)))
                ;; Set the transfer process properties.
                (tramp-set-connection-property
                 v "process-name" (buffer-name (current-buffer)))
                (tramp-set-connection-property
                 v "process-buffer" (current-buffer))
                (while copy-env
                  (tramp-message
                   orig-vec 6 "%s=\"%s\"" (car copy-env) (cadr copy-env))
                  (setenv (pop copy-env) (pop copy-env)))
                (setq
                 copy-args
                 (append
                  copy-args
                  (if remote-copy-program
                      (list (if t1 (concat ">" target) (concat "<" source)))
                    (list source target))))

                ;; Use an asynchronous process.  By this, password can
                ;; be handled.  We don't set a timeout, because the
                ;; copying of large files can last longer than 60
                ;; secs.
                (let ((p (apply 'start-process-shell-command
                                (tramp-get-connection-name v)
                                (tramp-get-connection-buffer v)
                                copy-program
                                (append
                                 copy-args
                                 (list "&&" "echo" "tramp_exit_status" "0"
                                       "||" "echo" "tramp_exit_status" "1")))))
                  (tramp-message
                   orig-vec 6 "%s"
                   (mapconcat 'identity (process-command p) " "))
                  (tramp-set-connection-property p "vector" orig-vec)
                  (set-process-query-on-exit-flag p nil)

                  ;; We must adapt `tramp-local-end-of-line' for
                  ;; sending the password.
                  (let ((tramp-local-end-of-line tramp-rsh-end-of-line))
                    (tramp-process-actions
                     p v nil tramp-actions-copy-out-of-band))

                  ;; Check the return code.
                  (goto-char (point-max))
                  (unless
                      (re-search-backward "tramp_exit_status [0-9]+" nil t)
                    (tramp-error
                     orig-vec 'file-error
                     "Couldn't find exit status of `%s'"
                     (mapconcat 'identity (process-command p) " ")))
                  (skip-chars-forward "^ ")
                  (unless (zerop (read (current-buffer)))
                    (forward-line -1)
                    (tramp-error
                     orig-vec 'file-error
                     "Error copying: `%s'"
                     (buffer-substring (point-min) (point-at-eol))))))

            ;; Reset the transfer process properties.
            (tramp-set-connection-property v "process-name" nil)
            (tramp-set-connection-property v "process-buffer" nil)
            ;; Clear the remote prompt.
            (when (and remote-copy-program
                       (not (tramp-send-command-and-check v nil)))
              ;; Houston, we have a problem!  Likely, the listener is
              ;; still running, so let's clear everything (but the
              ;; cached password).
              (tramp-cleanup-connection v 'keep-debug 'keep-password))))

        ;; Handle KEEP-DATE argument.
        (when (and keep-date (not copy-keep-date))
          (set-file-times newname (nth 5 (file-attributes filename))))

        ;; Set the mode.
        (unless (and keep-date copy-keep-date)
          (ignore-errors
            (set-file-modes newname (tramp-default-file-modes filename)))))

      ;; If the operation was `rename', delete the original file.
      (unless (eq op 'copy)
        (if (file-regular-p filename)
            (delete-file filename)
          (delete-directory filename 'recursive))))))

(defun tramp-sh-handle-make-directory (dir &optional parents)
  "Like `make-directory' for Tramp files."
  (setq dir (expand-file-name dir))
  (with-parsed-tramp-file-name dir nil
    (tramp-flush-directory-property v (file-name-directory localname))
    (save-excursion
      (tramp-barf-unless-okay
       v (format "%s %s"
                 (if parents "mkdir -p" "mkdir")
                 (tramp-shell-quote-argument localname))
       "Couldn't make directory %s" dir))))

(defun tramp-sh-handle-delete-directory (directory &optional recursive)
  "Like `delete-directory' for Tramp files."
  (setq directory (expand-file-name directory))
  (with-parsed-tramp-file-name directory nil
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-directory-property v localname)
    (tramp-barf-unless-okay
     v (format "cd / && %s %s"
               (if recursive "rm -rf" "rmdir")
               (tramp-shell-quote-argument localname))
     "Couldn't delete %s" directory)))

(defun tramp-sh-handle-delete-file (filename &optional trash)
  "Like `delete-file' for Tramp files."
  (setq filename (expand-file-name filename))
  (with-parsed-tramp-file-name filename nil
    (tramp-flush-file-property v (file-name-directory localname))
    (tramp-flush-file-property v localname)
    (tramp-barf-unless-okay
     v (format "%s %s"
               (or (and trash (tramp-get-remote-trash v)) "rm -f")
               (tramp-shell-quote-argument localname))
     "Couldn't delete %s" filename)))

;; Dired.

(defvar dired-compress-file-suffixes)
(declare-function dired-remove-file "dired-aux")

(defun tramp-sh-handle-dired-compress-file (file)
  "Like `dired-compress-file' for Tramp files."
  ;; Code stolen mainly from dired-aux.el.
  (with-parsed-tramp-file-name file nil
    (tramp-flush-file-property v localname)
    (save-excursion
      (let ((suffixes dired-compress-file-suffixes)
            suffix)
        ;; See if any suffix rule matches this file name.
        (while suffixes
          (let (case-fold-search)
            (if (string-match (car (car suffixes)) localname)
                (setq suffix (car suffixes) suffixes nil))
            (setq suffixes (cdr suffixes))))

        (cond ((file-symlink-p file)
               nil)
              ((and suffix (nth 2 suffix))
               ;; We found an uncompression rule.
               (with-tramp-progress-reporter
                   v 0 (format "Uncompressing %s" file)
                 (when (tramp-send-command-and-check
                        v (concat (nth 2 suffix) " "
                                  (tramp-shell-quote-argument localname)))
                   (dired-remove-file file)
                   (string-match (car suffix) file)
                   (concat (substring file 0 (match-beginning 0))))))
              (t
               ;; We don't recognize the file as compressed, so compress it.
               ;; Try gzip.
               (with-tramp-progress-reporter v 0 (format "Compressing %s" file)
                 (when (tramp-send-command-and-check
                        v (concat "gzip -f "
                                  (tramp-shell-quote-argument localname)))
                   (dired-remove-file file)
                   (cond ((file-exists-p (concat file ".gz"))
                          (concat file ".gz"))
                         ((file-exists-p (concat file ".z"))
                          (concat file ".z"))
                         (t nil))))))))))

(defun tramp-sh-handle-insert-directory
  (filename switches &optional wildcard full-directory-p)
  "Like `insert-directory' for Tramp files."
  (setq filename (expand-file-name filename))
  (unless switches (setq switches ""))
  (with-parsed-tramp-file-name filename nil
    (if (and (featurep 'ls-lisp)
             (not (symbol-value 'ls-lisp-use-insert-directory-program)))
        (tramp-handle-insert-directory
         filename switches wildcard full-directory-p)
      (when (stringp switches)
        (setq switches (split-string switches)))
      (when (and (member "--dired" switches)
                 (not (tramp-get-ls-command-with-dired v)))
        (setq switches (delete "--dired" switches)))
      (when wildcard
        (setq wildcard (tramp-run-real-handler
                        'file-name-nondirectory (list localname)))
        (setq localname (tramp-run-real-handler
                         'file-name-directory (list localname))))
      (unless (or full-directory-p (member "-d" switches))
        (setq switches (append switches '("-d"))))
      (setq switches (mapconcat 'tramp-shell-quote-argument switches " "))
      (when wildcard
        (setq switches (concat switches " " wildcard)))
      (tramp-message
       v 4 "Inserting directory `ls %s %s', wildcard %s, fulldir %s"
       switches filename (if wildcard "yes" "no")
       (if full-directory-p "yes" "no"))
      ;; If `full-directory-p', we just say `ls -l FILENAME'.
      ;; Else we chdir to the parent directory, then say `ls -ld BASENAME'.
      (if full-directory-p
          (tramp-send-command
           v
           (format "%s %s %s 2>/dev/null"
                   (tramp-get-ls-command v)
                   switches
                   (if wildcard
                       localname
                     (tramp-shell-quote-argument (concat localname ".")))))
        (tramp-barf-unless-okay
         v
         (format "cd %s" (tramp-shell-quote-argument
                          (tramp-run-real-handler
                           'file-name-directory (list localname))))
         "Couldn't `cd %s'"
         (tramp-shell-quote-argument
          (tramp-run-real-handler 'file-name-directory (list localname))))
        (tramp-send-command
         v
         (format "%s %s %s 2>/dev/null"
                 (tramp-get-ls-command v)
                 switches
                 (if (or wildcard
                         (zerop (length
                                 (tramp-run-real-handler
                                  'file-name-nondirectory (list localname)))))
                     ""
                   (tramp-shell-quote-argument
                    (tramp-run-real-handler
                     'file-name-nondirectory (list localname)))))))

      (save-restriction
        (let ((beg (point)))
          (narrow-to-region (point) (point))
          ;; We cannot use `insert-buffer-substring' because the Tramp
          ;; buffer changes its contents before insertion due to calling
          ;; `expand-file-name' and alike.
          (insert
           (with-current-buffer (tramp-get-buffer v)
             (buffer-string)))

          ;; Check for "--dired" output.
          (forward-line -2)
          (when (looking-at "//SUBDIRED//")
            (forward-line -1))
          (when (looking-at "//DIRED//\\s-+")
            (let ((databeg (match-end 0))
                  (end (point-at-eol)))
              ;; Now read the numeric positions of file names.
              (goto-char databeg)
              (while (< (point) end)
                (let ((start (+ beg (read (current-buffer))))
                      (end (+ beg (read (current-buffer)))))
                  (if (memq (char-after end) '(?\n ?\ ))
                      ;; End is followed by \n or by " -> ".
                      (put-text-property start end 'dired-filename t))))))
          ;; Remove trailing lines.
          (goto-char (point-at-bol))
          (while (looking-at "//")
            (forward-line 1)
            (delete-region (match-beginning 0) (point)))

          ;; Some busyboxes are reluctant to discard colors.
          (unless
              (string-match "color" (tramp-get-connection-property v "ls" ""))
            (goto-char beg)
            (while
                (re-search-forward tramp-display-escape-sequence-regexp nil t)
              (replace-match "")))

          ;; Decode the output, it could be multibyte.
          (decode-coding-region
           beg (point-max)
           (or file-name-coding-system default-file-name-coding-system))

          ;; The inserted file could be from somewhere else.
          (when (and (not wildcard) (not full-directory-p))
            (goto-char (point-max))
            (when (file-symlink-p filename)
              (goto-char (search-backward "->" beg 'noerror)))
            (search-backward
             (if (zerop (length (file-name-nondirectory filename)))
                 "."
               (file-name-nondirectory filename))
             beg 'noerror)
            (replace-match (file-relative-name filename) t))

          (goto-char (point-max)))))))

;; Canonicalization of file names.

(defun tramp-sh-handle-expand-file-name (name &optional dir)
  "Like `expand-file-name' for Tramp files.
If the localname part of the given file name starts with \"/../\" then
the result will be a local, non-Tramp, file name."
  ;; If DIR is not given, use `default-directory' or "/".
  (setq dir (or dir default-directory "/"))
  ;; Unless NAME is absolute, concat DIR and NAME.
  (unless (file-name-absolute-p name)
    (setq name (concat (file-name-as-directory dir) name)))
  ;; If connection is not established yet, run the real handler.
  (if (not (tramp-connectable-p name))
      (tramp-drop-volume-letter
       (tramp-run-real-handler 'expand-file-name (list name nil)))
    ;; Dissect NAME.
    (with-parsed-tramp-file-name name nil
      (unless (tramp-run-real-handler 'file-name-absolute-p (list localname))
        (setq localname (concat "~/" localname)))
      ;; Tilde expansion if necessary.  This needs a shell which
      ;; groks tilde expansion!  The function `tramp-find-shell' is
      ;; supposed to find such a shell on the remote host.  Please
      ;; tell me about it when this doesn't work on your system.
      (when (string-match "\\`\\(~[^/]*\\)\\(.*\\)\\'" localname)
        (let ((uname (match-string 1 localname))
              (fname (match-string 2 localname)))
          ;; We cannot simply apply "~/", because under sudo "~/" is
          ;; expanded to the local user home directory but to the
          ;; root home directory.  On the other hand, using always
          ;; the default user name for tilde expansion is not
          ;; appropriate either, because ssh and companions might
          ;; use a user name from the config file.
          (when (and (string-equal uname "~")
                     (string-match "\\`su\\(do\\)?\\'" method))
            (setq uname (concat uname user)))
          (setq uname
                (with-tramp-connection-property v uname
                  (tramp-send-command
                   v (format "cd %s && pwd" (tramp-shell-quote-argument uname)))
                  (with-current-buffer (tramp-get-buffer v)
                    (goto-char (point-min))
                    (buffer-substring (point) (point-at-eol)))))
          (setq localname (concat uname fname))))
      ;; There might be a double slash, for example when "~/"
      ;; expands to "/".  Remove this.
      (while (string-match "//" localname)
        (setq localname (replace-match "/" t t localname)))
      ;; No tilde characters in file name, do normal
      ;; `expand-file-name' (this does "/./" and "/../").
      ;; `default-directory' is bound, because on Windows there would
      ;; be problems with UNC shares or Cygwin mounts.
      (let ((default-directory (tramp-compat-temporary-file-directory)))
        (tramp-make-tramp-file-name
         method user host
         (tramp-drop-volume-letter
          (tramp-run-real-handler
           'expand-file-name (list localname)))
         hop)))))

;;; Remote commands:

(defun tramp-process-sentinel (proc event)
  "Flush file caches."
  (unless (memq (process-status proc) '(run open))
    (let ((vec (tramp-get-connection-property proc "vector" nil)))
      (when vec
        (tramp-message vec 5 "Sentinel called: `%S' `%s'" proc event)
        (tramp-flush-connection-property proc)
        (tramp-flush-directory-property vec "")))))

;; We use BUFFER also as connection buffer during setup. Because of
;; this, its original contents must be saved, and restored once
;; connection has been setup.
(defun tramp-sh-handle-start-file-process (name buffer program &rest args)
  "Like `start-file-process' for Tramp files."
  (with-parsed-tramp-file-name (expand-file-name default-directory) nil
    (let* ((buffer
            (if buffer
                (get-buffer-create buffer)
              ;; BUFFER can be nil.  We use a temporary buffer.
              (generate-new-buffer tramp-temp-buffer-name)))
           ;; When PROGRAM matches "*sh", and the first arg is "-c",
           ;; it might be that the arguments exceed the command line
           ;; length.  Therefore, we modify the command.
           (heredoc (and (stringp program)
                         (string-match "sh$" program)
                         (string-equal "-c" (car args))
                         (= (length args) 2)))
           ;; When PROGRAM is nil, we just provide a tty.
           (args (if (not heredoc) args
                   (let ((i 250))
                     (while (and (< i (length (cadr args)))
                                 (string-match " " (cadr args) i))
                       (setcdr
                        args
                        (list (replace-match " \\\\\n" nil nil (cadr args))))
                       (setq i (+ i 250))))
                   (cdr args)))
           ;; Use a human-friendly prompt, for example for `shell'.
           ;; We discard hops, if existing, that's why we cannot use
           ;; `file-remote-p'.
           (prompt (format "PS1=%s %s"
                           (tramp-make-tramp-file-name
                            (tramp-file-name-method v)
                            (tramp-file-name-user v)
                            (tramp-file-name-host v)
                            (tramp-file-name-localname v))
                           tramp-initial-end-of-output))
           ;; We use as environment the difference to toplevel
           ;; `process-environment'.
           env
           (env
            (dolist
                (elt
                 (cons prompt (nreverse (copy-sequence process-environment)))
                 env)
              (or (member elt (default-toplevel-value 'process-environment))
                  (setq env (cons elt env)))))
           (command
            (when (stringp program)
              (format "cd %s && exec %s env %s %s"
                      (tramp-shell-quote-argument localname)
                      (if heredoc (format "<<'%s'" tramp-end-of-heredoc) "")
                      (mapconcat 'tramp-shell-quote-argument env " ")
                      (if heredoc
                          (format "%s\n(\n%s\n) </dev/tty\n%s"
                                  program (car args) tramp-end-of-heredoc)
                        (mapconcat 'tramp-shell-quote-argument
                                   (cons program args) " ")))))
           (tramp-process-connection-type
            (or (null program) tramp-process-connection-type))
           (bmp (and (buffer-live-p buffer) (buffer-modified-p buffer)))
           (name1 name)
           (i 0)
           ;; We do not want to raise an error when
           ;; `start-file-process' has been started several times in
           ;; `eshell' and friends.
           (tramp-current-connection nil))

      (while (get-process name1)
        ;; NAME must be unique as process name.
        (setq i (1+ i)
              name1 (format "%s<%d>" name i)))
      (setq name name1)
      ;; Set the new process properties.
      (tramp-set-connection-property v "process-name" name)
      (tramp-set-connection-property v "process-buffer" buffer)

      (with-current-buffer (tramp-get-connection-buffer v)
        (unwind-protect
            ;; We catch this event.  Otherwise, `start-process' could
            ;; be called on the local host.
            (save-excursion
              (save-restriction
                ;; Activate narrowing in order to save BUFFER
                ;; contents.  Clear also the modification time;
                ;; otherwise we might be interrupted by
                ;; `verify-visited-file-modtime'.
                (let ((buffer-undo-list t)
                      (buffer-read-only nil)
                      (mark (point-max)))
                  (clear-visited-file-modtime)
                  (narrow-to-region (point-max) (point-max))
                  ;; We call `tramp-maybe-open-connection', in order
                  ;; to cleanup the prompt afterwards.
                  (catch 'suppress
                    (tramp-maybe-open-connection v)
                    (widen)
                    (delete-region mark (point))
                    (narrow-to-region (point-max) (point-max))
                    ;; Now do it.
                    (if command
                        ;; Send the command.
                        (tramp-send-command v command nil t) ; nooutput
                      ;; Check, whether a pty is associated.
                      (unless (process-get
                               (tramp-get-connection-process v) 'remote-tty)
                        (tramp-error
                         v 'file-error
                         "pty association is not supported for `%s'" name))))
                  (let ((p (tramp-get-connection-process v)))
                    ;; Set query flag and process marker for this
                    ;; process.  We ignore errors, because the process
                    ;; could have finished already.
                    (ignore-errors
                      (set-process-query-on-exit-flag p t)
                      (set-marker (process-mark p) (point)))
                    ;; Return process.
                    p))))

          ;; Save exit.
          (if (string-match tramp-temp-buffer-name (buffer-name))
              (ignore-errors
                (set-process-buffer (tramp-get-connection-process v) nil)
                (kill-buffer (current-buffer)))
            (set-buffer-modified-p bmp))
          (tramp-set-connection-property v "process-name" nil)
          (tramp-set-connection-property v "process-buffer" nil))))))

(defun tramp-sh-handle-process-file
  (program &optional infile destination display &rest args)
  "Like `process-file' for Tramp files."
  ;; The implementation is not complete yet.
  (when (and (numberp destination) (zerop destination))
    (error "Implementation does not handle immediate return"))

  (with-parsed-tramp-file-name default-directory nil
    (let (command env input tmpinput stderr tmpstderr outbuf ret)
      ;; Compute command.
      (setq command (mapconcat 'tramp-shell-quote-argument
                               (cons program args) " "))
      ;; We use as environment the difference to toplevel `process-environment'.
      (setq env
            (dolist (elt (nreverse (copy-sequence process-environment)) env)
              (or (member elt (default-toplevel-value 'process-environment))
                  (setq env (cons elt env)))))
      (when env
        (setq command
              (format
               "env %s %s"
               (mapconcat 'tramp-shell-quote-argument env " ") command)))
      ;; Determine input.
      (if (null infile)
          (setq input "/dev/null")
        (setq infile (expand-file-name infile))
        (if (tramp-equal-remote default-directory infile)
            ;; INFILE is on the same remote host.
            (setq input (with-parsed-tramp-file-name infile nil localname))
          ;; INFILE must be copied to remote host.
          (setq input (tramp-make-tramp-temp-file v)
                tmpinput (tramp-make-tramp-file-name method user host input))
          (copy-file infile tmpinput t)))
      (when input (setq command (format "%s <%s" command input)))

      ;; Determine output.
      (cond
       ;; Just a buffer.
       ((bufferp destination)
        (setq outbuf destination))
       ;; A buffer name.
       ((stringp destination)
        (setq outbuf (get-buffer-create destination)))
       ;; (REAL-DESTINATION ERROR-DESTINATION)
       ((consp destination)
        ;; output.
        (cond
         ((bufferp (car destination))
          (setq outbuf (car destination)))
         ((stringp (car destination))
          (setq outbuf (get-buffer-create (car destination))))
         ((car destination)
          (setq outbuf (current-buffer))))
        ;; stderr.
        (cond
         ((stringp (cadr destination))
          (setcar (cdr destination) (expand-file-name (cadr destination)))
          (if (tramp-equal-remote default-directory (cadr destination))
              ;; stderr is on the same remote host.
              (setq stderr (with-parsed-tramp-file-name
                               (cadr destination) nil localname))
            ;; stderr must be copied to remote host.  The temporary
            ;; file must be deleted after execution.
            (setq stderr (tramp-make-tramp-temp-file v)
                  tmpstderr (tramp-make-tramp-file-name
                             method user host stderr))))
         ;; stderr to be discarded.
         ((null (cadr destination))
          (setq stderr "/dev/null"))))
       ;; 't
       (destination
        (setq outbuf (current-buffer))))
      (when stderr (setq command (format "%s 2>%s" command stderr)))

      ;; Send the command.  It might not return in time, so we protect
      ;; it.  Call it in a subshell, in order to preserve working
      ;; directory.
      (condition-case nil
          (unwind-protect
              (setq ret
                    (if (tramp-send-command-and-check
                         v (format "cd %s && %s"
                                   (tramp-shell-quote-argument localname)
                                   command)
                         t t)
                        0 1))
            ;; We should add the output anyway.
            (when outbuf
              (with-current-buffer outbuf
                (insert
                 (with-current-buffer (tramp-get-connection-buffer v)
                   (buffer-string))))
              (when (and display (get-buffer-window outbuf t)) (redisplay))))
        ;; When the user did interrupt, we should do it also.  We use
        ;; return code -1 as marker.
        (quit
         (kill-buffer (tramp-get-connection-buffer v))
         (setq ret -1))
        ;; Handle errors.
        (error
         (kill-buffer (tramp-get-connection-buffer v))
         (setq ret 1)))

      ;; Provide error file.
      (when tmpstderr (rename-file tmpstderr (cadr destination) t))

      ;; Cleanup.  We remove all file cache values for the connection,
      ;; because the remote process could have changed them.
      (when tmpinput (delete-file tmpinput))

      (unless process-file-side-effects
        (tramp-flush-directory-property v ""))

      ;; Return exit status.
      (if (equal ret -1)
          (keyboard-quit)
        ret))))

(defun tramp-sh-handle-file-local-copy (filename)
  "Like `file-local-copy' for Tramp files."
  (with-parsed-tramp-file-name filename nil
    (unless (file-exists-p filename)
      (tramp-error
       v 'file-error
       "Cannot make local copy of non-existing file `%s'" filename))

    (let* ((size (nth 7 (file-attributes (file-truename filename))))
           (rem-enc (tramp-get-inline-coding v "remote-encoding" size))
           (loc-dec (tramp-get-inline-coding v "local-decoding" size))
           (tmpfile (tramp-compat-make-temp-file filename)))

      (condition-case err
          (cond
           ;; `copy-file' handles direct copy and out-of-band methods.
           ((or (tramp-local-host-p v)
                (tramp-method-out-of-band-p v size))
            (copy-file filename tmpfile 'ok-if-already-exists 'keep-time))

           ;; Use inline encoding for file transfer.
           (rem-enc
            (save-excursion
              (with-tramp-progress-reporter
               v 3
               (format-message "Encoding remote file `%s' with `%s'"
                               filename rem-enc)
               (tramp-barf-unless-okay
                v (format rem-enc (tramp-shell-quote-argument localname))
                "Encoding remote file failed"))

              (with-tramp-progress-reporter
                  v 3 (format-message "Decoding local file `%s' with `%s'"
                                      tmpfile loc-dec)
                (if (functionp loc-dec)
                    ;; If local decoding is a function, we call it.
                    ;; We must disable multibyte, because
                    ;; `uudecode-decode-region' doesn't handle it
                    ;; correctly.  Unset `file-name-handler-alist'.
                    ;; Otherwise, epa-file gets confused.
                    (let (file-name-handler-alist
                          (coding-system-for-write 'binary))
                      (with-temp-file tmpfile
                        (set-buffer-multibyte nil)
                        (insert-buffer-substring (tramp-get-buffer v))
                        (funcall loc-dec (point-min) (point-max))))

                  ;; If tramp-decoding-function is not defined for this
                  ;; method, we invoke tramp-decoding-command instead.
                  (let ((tmpfile2 (tramp-compat-make-temp-file filename)))
                    ;; Unset `file-name-handler-alist'.  Otherwise,
                    ;; epa-file gets confused.
                    (let (file-name-handler-alist
                          (coding-system-for-write 'binary))
                      (with-current-buffer (tramp-get-buffer v)
                        (write-region
                         (point-min) (point-max) tmpfile2 nil 'no-message)))
                    (unwind-protect
                        (tramp-call-local-coding-command
                         loc-dec tmpfile2 tmpfile)
                      (delete-file tmpfile2)))))

              ;; Set proper permissions.
              (set-file-modes tmpfile (tramp-default-file-modes filename))
              ;; Set local user ownership.
              (tramp-set-file-uid-gid tmpfile)))

           ;; Oops, I don't know what to do.
           (t (tramp-error
               v 'file-error "Wrong method specification for `%s'" method)))

        ;; Error handling.
        ((error quit)
         (delete-file tmpfile)
         (signal (car err) (cdr err))))

      (run-hooks 'tramp-handle-file-local-copy-hook)
      tmpfile)))

;; CCC grok LOCKNAME
(defun tramp-sh-handle-write-region
  (start end filename &optional append visit lockname confirm)
  "Like `write-region' for Tramp files."
  (setq filename (expand-file-name filename))
  (with-parsed-tramp-file-name filename nil
    ;; Following part commented out because we don't know what to do about
    ;; file locking, and it does not appear to be a problem to ignore it.
    ;; Ange-ftp ignores it, too.
    ;;  (when (and lockname (stringp lockname))
    ;;    (setq lockname (expand-file-name lockname)))
    ;;  (unless (or (eq lockname nil)
    ;;              (string= lockname filename))
    ;;    (error
    ;;     "tramp-sh-handle-write-region: LOCKNAME must be nil or equal FILENAME"))

    (when (and confirm (file-exists-p filename))
      (unless (y-or-n-p (format "File %s exists; overwrite anyway? " filename))
        (tramp-error v 'file-error "File not overwritten")))

    (let ((uid (or (nth 2 (file-attributes filename 'integer))
                   (tramp-get-remote-uid v 'integer)))
          (gid (or (nth 3 (file-attributes filename 'integer))
                   (tramp-get-remote-gid v 'integer))))

      (if (and (tramp-local-host-p v)
               ;; `file-writable-p' calls `file-expand-file-name'.  We
               ;; cannot use `tramp-run-real-handler' therefore.
               (let (file-name-handler-alist)
                 (and
                  (file-writable-p (file-name-directory localname))
                  (or (file-directory-p localname)
                      (file-writable-p localname)))))
          ;; Short track: if we are on the local host, we can run directly.
          (tramp-run-real-handler
           'write-region
           (list start end localname append 'no-message lockname confirm))

        (let* ((modes (save-excursion (tramp-default-file-modes filename)))
               ;; We use this to save the value of
               ;; `last-coding-system-used' after writing the tmp
               ;; file.  At the end of the function, we set
               ;; `last-coding-system-used' to this saved value.  This
               ;; way, any intermediary coding systems used while
               ;; talking to the remote shell or suchlike won't hose
               ;; this variable.  This approach was snarfed from
               ;; ange-ftp.el.
               coding-system-used
               ;; Write region into a tmp file.  This isn't really
               ;; needed if we use an encoding function, but currently
               ;; we use it always because this makes the logic
               ;; simpler.  We must also set `temporary-file-directory',
               ;; because it could point to a remote directory.
               (temporary-file-directory
                (tramp-compat-temporary-file-directory))
               (tmpfile (or tramp-temp-buffer-file-name
                            (tramp-compat-make-temp-file filename))))

          ;; If `append' is non-nil, we copy the file locally, and let
          ;; the native `write-region' implementation do the job.
          (when append (copy-file filename tmpfile 'ok))

          ;; We say `no-message' here because we don't want the
          ;; visited file modtime data to be clobbered from the temp
          ;; file.  We call `set-visited-file-modtime' ourselves later
          ;; on.  We must ensure that `file-coding-system-alist'
          ;; matches `tmpfile'.
          (let (file-name-handler-alist
                (file-coding-system-alist
                 (tramp-find-file-name-coding-system-alist filename tmpfile)))
            (condition-case err
                (tramp-run-real-handler
                 'write-region
                 (list start end tmpfile append 'no-message lockname confirm))
              ((error quit)
               (setq tramp-temp-buffer-file-name nil)
               (delete-file tmpfile)
               (signal (car err) (cdr err))))

            ;; Now, `last-coding-system-used' has the right value.  Remember it.
            (setq coding-system-used last-coding-system-used))

          ;; The permissions of the temporary file should be set.  If
          ;; FILENAME does not exist (eq modes nil) it has been
          ;; renamed to the backup file.  This case `save-buffer'
          ;; handles permissions.
          ;; Ensure that it is still readable.
          (when modes
            (set-file-modes
             tmpfile
             (logior (or modes 0) (string-to-number "0400" 8))))

          ;; This is a bit lengthy due to the different methods
          ;; possible for file transfer.  First, we check whether the
          ;; method uses an scp program.  If so, we call it.
          ;; Otherwise, both encoding and decoding command must be
          ;; specified.  However, if the method _also_ specifies an
          ;; encoding function, then that is used for encoding the
          ;; contents of the tmp file.
          (let* ((size (nth 7 (file-attributes tmpfile)))
                 (rem-dec (tramp-get-inline-coding v "remote-decoding" size))
                 (loc-enc (tramp-get-inline-coding v "local-encoding" size)))
            (cond
             ;; `copy-file' handles direct copy and out-of-band methods.
             ((or (tramp-local-host-p v)
                  (tramp-method-out-of-band-p v size))
              (if (and (not (stringp start))
                       (= (or end (point-max)) (point-max))
                       (= (or start (point-min)) (point-min))
                       (tramp-get-method-parameter v 'tramp-copy-keep-tmpfile))
                  (progn
                    (setq tramp-temp-buffer-file-name tmpfile)
                    (condition-case err
                        ;; We keep the local file for performance
                        ;; reasons, useful for "rsync".
                        (copy-file tmpfile filename t)
                      ((error quit)
                       (setq tramp-temp-buffer-file-name nil)
                       (delete-file tmpfile)
                       (signal (car err) (cdr err)))))
                (setq tramp-temp-buffer-file-name nil)
                ;; Don't rename, in order to keep context in SELinux.
                (unwind-protect
                    (copy-file tmpfile filename t)
                  (delete-file tmpfile))))

             ;; Use inline file transfer.
             (rem-dec
              ;; Encode tmpfile.
              (unwind-protect
                  (with-temp-buffer
                    (set-buffer-multibyte nil)
                    ;; Use encoding function or command.
                    (with-tramp-progress-reporter
                        v 3 (format-message
                             "Encoding local file `%s' using `%s'"
                             tmpfile loc-enc)
                      (if (functionp loc-enc)
                          ;; The following `let' is a workaround for
                          ;; the base64.el that comes with pgnus-0.84.
                          ;; If both of the following conditions are
                          ;; satisfied, it tries to write to a local
                          ;; file in default-directory, but at this
                          ;; point, default-directory is remote.
                          ;; (`call-process-region' can't write to
                          ;; remote files, it seems.)  The file in
                          ;; question is a tmp file anyway.
                          (let ((coding-system-for-read 'binary)
                                (default-directory
                                  (tramp-compat-temporary-file-directory)))
                            (insert-file-contents-literally tmpfile)
                            (funcall loc-enc (point-min) (point-max)))

                        (unless (zerop (tramp-call-local-coding-command
                                        loc-enc tmpfile t))
                          (tramp-error
                           v 'file-error
                           (concat "Cannot write to `%s', "
                                   "local encoding command `%s' failed")
                           filename loc-enc))))

                    ;; Send buffer into remote decoding command which
                    ;; writes to remote file.  Because this happens on
                    ;; the remote host, we cannot use the function.
                    (with-tramp-progress-reporter
                        v 3 (format-message
                             "Decoding remote file `%s' using `%s'"
                             filename rem-dec)
                      (goto-char (point-max))
                      (unless (bolp) (newline))
                      (tramp-send-command
                       v
                       (format
                        (concat rem-dec " <<'%s'\n%s%s")
                        (tramp-shell-quote-argument localname)
                        tramp-end-of-heredoc
                        (buffer-string)
                        tramp-end-of-heredoc))
                      (tramp-barf-unless-okay
                       v nil
                       "Couldn't write region to `%s', decode using `%s' failed"
                       filename rem-dec)
                      ;; When `file-precious-flag' is set, the region is
                      ;; written to a temporary file.  Check that the
                      ;; checksum is equal to that from the local tmpfile.
                      (when file-precious-flag
                        (erase-buffer)
                        (and
                         ;; cksum runs locally, if possible.
                         (zerop (tramp-call-process v "cksum" tmpfile t))
                         ;; cksum runs remotely.
                         (tramp-send-command-and-check
                          v
                          (format
                           "cksum <%s" (tramp-shell-quote-argument localname)))
                         ;; ... they are different.
                         (not
                          (string-equal
                           (buffer-string)
                           (with-current-buffer (tramp-get-buffer v)
                             (buffer-string))))
                         (tramp-error
                          v 'file-error
                          (concat "Couldn't write region to `%s',"
                                  " decode using `%s' failed")
                          filename rem-dec)))))

                ;; Save exit.
                (delete-file tmpfile)))

             ;; That's not expected.
             (t
              (tramp-error
               v 'file-error
               (concat "Method `%s' should specify both encoding and "
                       "decoding command or an scp program")
               method))))

          ;; Make `last-coding-system-used' have the right value.
          (when coding-system-used
            (set 'last-coding-system-used coding-system-used))))

      (tramp-flush-file-property v (file-name-directory localname))
      (tramp-flush-file-property v localname)

      ;; We must protect `last-coding-system-used', now we have set it
      ;; to its correct value.
      (let (last-coding-system-used (need-chown t))
        ;; Set file modification time.
        (when (or (eq visit t) (stringp visit))
          (let ((file-attr (file-attributes filename 'integer)))
            (set-visited-file-modtime
             ;; We must pass modtime explicitly, because FILENAME can
             ;; be different from (buffer-file-name), f.e. if
             ;; `file-precious-flag' is set.
             (nth 5 file-attr))
            (when (and (= (nth 2 file-attr) uid)
                       (= (nth 3 file-attr) gid))
              (setq need-chown nil))))

        ;; Set the ownership.
        (when need-chown
          (tramp-set-file-uid-gid filename uid gid))
        (when (or (eq visit t) (null visit) (stringp visit))
          (tramp-message v 0 "Wrote %s" filename))
        (run-hooks 'tramp-handle-write-region-hook)))))

(defvar tramp-vc-registered-file-names nil
  "List used to collect file names, which are checked during `vc-registered'.")

;; VC backends check for the existence of various different special
;; files.  This is very time consuming, because every single check
;; requires a remote command (the file cache must be invalidated).
;; Therefore, we apply a kind of optimization.  We install the file
;; name handler `tramp-vc-file-name-handler', which does nothing but
;; remembers all file names for which `file-exists-p' or
;; `file-readable-p' has been applied.  A first run of `vc-registered'
;; is performed.  Afterwards, a script is applied for all collected
;; file names, using just one remote command.  The result of this
;; script is used to fill the file cache with actual values.  Now we
;; can reset the file name handlers, and we make a second run of
;; `vc-registered', which returns the expected result without sending
;; any other remote command.
(defun tramp-sh-handle-vc-registered (file)
  "Like `vc-registered' for Tramp files."
  (with-temp-message ""
    (with-parsed-tramp-file-name file nil
      (with-tramp-progress-reporter
          v 3 (format-message "Checking `vc-registered' for %s" file)

        ;; There could be new files, created by the vc backend.  We
        ;; cannot reuse the old cache entries, therefore.  In
        ;; `tramp-get-file-property', `remote-file-name-inhibit-cache'
        ;; could also be a timestamp as `current-time' returns.  This
        ;; means invalidate all cache entries with an older timestamp.
        (let (tramp-vc-registered-file-names
              (remote-file-name-inhibit-cache (current-time))
              (file-name-handler-alist
               `((,tramp-file-name-regexp . tramp-vc-file-name-handler))))

          ;; Here we collect only file names, which need an operation.
          (ignore-errors (tramp-run-real-handler 'vc-registered (list file)))
          (tramp-message v 10 "\n%s" tramp-vc-registered-file-names)

          ;; Send just one command, in order to fill the cache.
          (when tramp-vc-registered-file-names
            (tramp-maybe-send-script
             v
             (format tramp-vc-registered-read-file-names
                     (tramp-get-file-exists-command v)
                     (format "%s -r" (tramp-get-test-command v)))
             "tramp_vc_registered_read_file_names")

            (dolist
                (elt
                 (ignore-errors
                   ;; We cannot use `tramp-send-command-and-read',
                   ;; because this does not cooperate well with
                   ;; heredoc documents.
                   (tramp-send-command
                    v
                    (format
                     "tramp_vc_registered_read_file_names <<'%s'\n%s\n%s\n"
                     tramp-end-of-heredoc
                     (mapconcat 'tramp-shell-quote-argument
                                tramp-vc-registered-file-names
                                "\n")
                     tramp-end-of-heredoc))
                   (with-current-buffer (tramp-get-connection-buffer v)
                     ;; Read the expression.
                     (goto-char (point-min))
                     (read (current-buffer)))))

              (tramp-set-file-property
               v (car elt) (cadr elt) (cadr (cdr elt))))))

        ;; Second run.  Now all `file-exists-p' or `file-readable-p'
        ;; calls shall be answered from the file cache.  We unset
        ;; `process-file-side-effects' and `remote-file-name-inhibit-cache'
        ;; in order to keep the cache.
        (let ((vc-handled-backends vc-handled-backends)
              remote-file-name-inhibit-cache process-file-side-effects)
          ;; Reduce `vc-handled-backends' in order to minimize process calls.
          (when (and (memq 'Bzr vc-handled-backends)
                     (boundp 'vc-bzr-program)
                     (not (with-tramp-connection-property v vc-bzr-program
                            (tramp-find-executable
                             v vc-bzr-program (tramp-get-remote-path v)))))
            (setq vc-handled-backends (remq 'Bzr vc-handled-backends)))
          (when (and (memq 'Git vc-handled-backends)
                     (boundp 'vc-git-program)
                     (not (with-tramp-connection-property v vc-git-program
                            (tramp-find-executable
                             v vc-git-program (tramp-get-remote-path v)))))
            (setq vc-handled-backends (remq 'Git vc-handled-backends)))
          (when (and (memq 'Hg vc-handled-backends)
                     (boundp 'vc-hg-program)
                     (not (with-tramp-connection-property v vc-hg-program
                            (tramp-find-executable
                             v vc-hg-program (tramp-get-remote-path v)))))
            (setq vc-handled-backends (remq 'Hg vc-handled-backends)))
          ;; Run.
          (ignore-errors
            (tramp-run-real-handler 'vc-registered (list file))))))))

;;;###tramp-autoload
(defun tramp-sh-file-name-handler (operation &rest args)
  "Invoke remote-shell Tramp file name handler.
Fall back to normal file name handler if no Tramp handler exists."
  (when (and tramp-locked (not tramp-locker))
    (setq tramp-locked nil)
    (tramp-error
     (car-safe tramp-current-connection) 'file-error
     "Forbidden reentrant call of Tramp"))
  (let ((tl tramp-locked))
    (setq tramp-locked t)
    (unwind-protect
        (let ((tramp-locker t))
          (save-match-data
            (let ((fn (assoc operation tramp-sh-file-name-handler-alist)))
              (if fn
                  (apply (cdr fn) args)
                (tramp-run-real-handler operation args)))))
      (setq tramp-locked tl))))

(defun tramp-vc-file-name-handler (operation &rest args)
  "Invoke special file name handler, which collects files to be handled."
  (save-match-data
    (let ((filename
           (tramp-replace-environment-variables
            (apply 'tramp-file-name-for-operation operation args)))
          (fn (assoc operation tramp-sh-file-name-handler-alist)))
      (with-parsed-tramp-file-name filename nil
        (cond
         ;; That's what we want: file names, for which checks are
         ;; applied.  We assume that VC uses only `file-exists-p' and
         ;; `file-readable-p' checks; otherwise we must extend the
         ;; list.  We do not perform any action, but return nil, in
         ;; order to keep `vc-registered' running.
         ((and fn (memq operation '(file-exists-p file-readable-p)))
          (add-to-list 'tramp-vc-registered-file-names localname 'append)
          nil)
         ;; `process-file' and `start-file-process' shall be ignored.
         ((and fn (eq operation 'process-file) 0))
         ((and fn (eq operation 'start-file-process) nil))
         ;; Tramp file name handlers like `expand-file-name'.  They
         ;; must still work.
         (fn (save-match-data (apply (cdr fn) args)))
         ;; Default file name handlers, we don't care.
         (t (tramp-run-real-handler operation args)))))))

(defun tramp-sh-handle-file-notify-add-watch (file-name flags _callback)
  "Like `file-notify-add-watch' for Tramp files."
  (setq file-name (expand-file-name file-name))
  (with-parsed-tramp-file-name file-name nil
    (let ((default-directory (file-name-directory file-name))
          command events filter p sequence)
      (cond
       ;; gvfs-monitor-dir.
       ((setq command (tramp-get-remote-gvfs-monitor-dir v))
        (setq filter 'tramp-sh-gvfs-monitor-dir-process-filter
              events
              (cond
               ((and (memq 'change flags) (memq 'attribute-change flags))
                '(created changed changes-done-hint moved deleted
                          attribute-changed))
               ((memq 'change flags)
                '(created changed changes-done-hint moved deleted))
               ((memq 'attribute-change flags) '(attribute-changed)))
              sequence `(,command ,localname)))
       ;; inotifywait.
       ((setq command (tramp-get-remote-inotifywait v))
        (setq filter 'tramp-sh-inotifywait-process-filter
              events
              (cond
               ((and (memq 'change flags) (memq 'attribute-change flags))
                (concat "create,modify,move,moved_from,moved_to,move_self,"
                        "delete,delete_self,attrib,ignored"))
               ((memq 'change flags)
                (concat "create,modify,move,moved_from,moved_to,move_self,"
                        "delete,delete_self,ignored"))
               ((memq 'attribute-change flags) "attrib,ignored"))
              sequence `(,command "-mq" "-e" ,events ,localname)
              ;; Make events a list of symbols.
              events
              (mapcar
               (lambda (x) (intern-soft (replace-regexp-in-string "_" "-" x)))
               (split-string events "," 'omit))))
       ;; None.
       (t (tramp-error
           v 'file-notify-error
           "No file notification program found on %s"
           (file-remote-p file-name))))
      ;; Start process.
      (setq p (apply
               'start-file-process
               (file-name-nondirectory command)
               (generate-new-buffer
                (format " *%s*" (file-name-nondirectory command)))
               sequence))
      ;; Return the process object as watch-descriptor.
      (if (not (processp p))
          (tramp-error
           v 'file-notify-error
           "`%s' failed to start on remote host"
           (mapconcat 'identity sequence " "))
        (tramp-message v 6 "Run `%s', %S" (mapconcat 'identity sequence " ") p)
        (tramp-set-connection-property p "vector" v)
        ;; Needed for process filter.
        (process-put p 'events events)
        (process-put p 'watch-name localname)
        (set-process-query-on-exit-flag p nil)
        (set-process-filter p filter)
        ;; There might be an error if the monitor is not supported.
        ;; Give the filter a chance to read the output.
        (tramp-accept-process-output p 1)
        (unless (memq (process-status p) '(run open))
          (tramp-error
           v 'file-notify-error "Monitoring not supported for `%s'" file-name))
        p))))

(defun tramp-sh-gvfs-monitor-dir-process-filter (proc string)
  "Read output from \"gvfs-monitor-dir\" and add corresponding \
file-notify events."
  (let ((events (process-get proc 'events))
        (remote-prefix
         (with-current-buffer (process-buffer proc)
           (file-remote-p default-directory)))
        (rest-string (process-get proc 'rest-string)))
    (when rest-string
      (tramp-message proc 10 "Previous string:\n%s" rest-string))
    (tramp-message proc 6 "%S\n%s" proc string)
    (setq string (concat rest-string string)
          ;; Attribute change is returned in unused wording.
          string (replace-regexp-in-string
                  "ATTRIB CHANGED" "ATTRIBUTE_CHANGED" string))
    (when (string-match "Monitoring not supported" string)
      (delete-process proc))

    (while (string-match
            (concat "^[\n\r]*"
                    "Directory Monitor Event:[\n\r]+"
                    "Child = \\([^\n\r]+\\)[\n\r]+"
                    "\\(Other = \\([^\n\r]+\\)[\n\r]+\\)?"
                    "Event = \\([^[:blank:]]+\\)[\n\r]+")
            string)
      (let* ((file (match-string 1 string))
             (file1 (match-string 3 string))
             (object
              (list
               proc
               (list
                (intern-soft
                 (replace-regexp-in-string
                  "_" "-" (downcase (match-string 4 string)))))
               ;; File names are returned as absolute paths.  We must
               ;; add the remote prefix.
               (concat remote-prefix file)
               (when file1 (concat remote-prefix file1)))))
        (setq string (replace-match "" nil nil string))
        ;; Remove watch when file or directory to be watched is deleted.
        (when (and (member (caadr object) '(moved deleted))
                   (string-equal file (process-get proc 'watch-name)))
          (delete-process proc))
        ;; Usually, we would add an Emacs event now.  Unfortunately,
        ;; `unread-command-events' does not accept several events at
        ;; once.  Therefore, we apply the handler directly.
        (when (member (caadr object) events)
          (tramp-compat-funcall
           'file-notify-handle-event
           `(file-notify ,object file-notify-callback)))))

    ;; Save rest of the string.
    (when (zerop (length string)) (setq string nil))
    (when string (tramp-message proc 10 "Rest string:\n%s" string))
    (process-put proc 'rest-string string)))

(defun tramp-sh-inotifywait-process-filter (proc string)
  "Read output from \"inotifywait\" and add corresponding file-notify events."
  (let ((events (process-get proc 'events)))
    (tramp-message proc 6 "%S\n%s" proc string)
    (dolist (line (split-string string "[\n\r]+" 'omit))
      ;; Check, whether there is a problem.
      (unless
          (string-match
           (concat "^[^[:blank:]]+"
                   "[[:blank:]]+\\([^[:blank:]]+\\)+"
                   "\\([[:blank:]]+\\([^\n\r]+\\)\\)?")
           line)
        (tramp-error proc 'file-notify-error "%s" line))

      (let ((object
             (list
              proc
              (mapcar
               (lambda (x)
                 (intern-soft
                  (replace-regexp-in-string "_" "-" (downcase x))))
               (split-string (match-string 1 line) "," 'omit))
              (match-string 3 line))))
        ;; Remove watch when file or directory to be watched is deleted.
        (when (member (caadr object) '(move-self delete-self ignored))
          (delete-process proc))
        ;; Usually, we would add an Emacs event now.  Unfortunately,
        ;; `unread-command-events' does not accept several events at
        ;; once.  Therefore, we apply the handler directly.
        (when (member (caadr object) events)
          (tramp-compat-funcall
           'file-notify-handle-event
           `(file-notify ,object file-notify-callback)))))))

;;; Internal Functions:

(defun tramp-maybe-send-script (vec script name)
  "Define in remote shell function NAME implemented as SCRIPT.
Only send the definition if it has not already been done."
  ;; We cannot let-bind (tramp-get-connection-process vec) because it
  ;; might be nil.
  (let ((scripts (tramp-get-connection-property
                  (tramp-get-connection-process vec) "scripts" nil)))
    (unless (member name scripts)
      (with-tramp-progress-reporter
          vec 5 (format-message "Sending script `%s'" name)
        ;; In bash, leading TABs like in `tramp-vc-registered-read-file-names'
        ;; could result in unwanted command expansion.  Avoid this.
        (setq script (replace-regexp-in-string
                      (make-string 1 ?\t) (make-string 8 ? ) script))
        ;; The script could contain a call of Perl.  This is masked with `%s'.
        (when (and (string-match "%s" script)
                   (not (tramp-get-remote-perl vec)))
          (tramp-error vec 'file-error "No Perl available on remote host"))
        (tramp-barf-unless-okay
         vec
         (format "%s () {\n%s\n}"
                 name (format script (tramp-get-remote-perl vec)))
         "Script %s sending failed" name)
        (tramp-set-connection-property
         (tramp-get-connection-process vec) "scripts" (cons name scripts))))))

(defun tramp-run-test (switch filename)
  "Run `test' on the remote system, given a SWITCH and a FILENAME.
Returns the exit code of the `test' program."
  (with-parsed-tramp-file-name filename nil
    (tramp-send-command-and-check
     v
     (format
      "%s %s %s"
      (tramp-get-test-command v)
      switch
      (tramp-shell-quote-argument localname)))))

(defun tramp-run-test2 (format-string file1 file2)
  "Run `test'-like program on the remote system, given FILE1, FILE2.
FORMAT-STRING contains the program name, switches, and place holders.
Returns the exit code of the `test' program.  Barfs if the methods,
hosts, or files, disagree."
  (unless (tramp-equal-remote file1 file2)
    (with-parsed-tramp-file-name (if (tramp-tramp-file-p file1) file1 file2) nil
      (tramp-error
       v 'file-error
       "tramp-run-test2 only implemented for same method, user, host")))
  (with-parsed-tramp-file-name file1 v1
    (with-parsed-tramp-file-name file1 v2
      (tramp-send-command-and-check
       v1
       (format format-string
               (tramp-shell-quote-argument v1-localname)
               (tramp-shell-quote-argument v2-localname))))))

(defun tramp-find-executable
  (vec progname dirlist &optional ignore-tilde ignore-path)
  "Searches for PROGNAME in $PATH and all directories mentioned in DIRLIST.
First arg VEC specifies the connection, PROGNAME is the program
to search for, and DIRLIST gives the list of directories to
search.  If IGNORE-TILDE is non-nil, directory names starting
with `~' will be ignored. If IGNORE-PATH is non-nil, searches
only in DIRLIST.

Returns the absolute file name of PROGNAME, if found, and nil otherwise.

This function expects to be in the right *tramp* buffer."
  (with-current-buffer (tramp-get-connection-buffer vec)
    (let (result)
      ;; Check whether the executable is in $PATH. "which(1)" does not
      ;; report always a correct error code; therefore we check the
      ;; number of words it returns.  "SunOS 5.10" (and maybe "SunOS
      ;; 5.11") have problems with this command, we disable the call
      ;; therefore.
      (unless (or ignore-path
                  (string-match
                   (regexp-opt '("SunOS 5.10" "SunOS 5.11"))
                   (tramp-get-connection-property vec "uname" "")))
        (tramp-send-command vec (format "which \\%s | wc -w" progname))
        (goto-char (point-min))
        (if (looking-at "^\\s-*1$")
            (setq result (concat "\\" progname))))
      (unless result
        (when ignore-tilde
          ;; Remove all ~/foo directories from dirlist.
          (let (newdl d)
            (while dirlist
              (setq d (car dirlist))
              (setq dirlist (cdr dirlist))
              (unless (char-equal ?~ (aref d 0))
                (setq newdl (cons d newdl))))
            (setq dirlist (nreverse newdl))))
        (tramp-send-command
         vec
         (format (concat "while read d; "
                         "do if test -x $d/%s && test -f $d/%s; "
                         "then echo tramp_executable $d/%s; "
                         "break; fi; done <<'%s'\n"
                         "%s\n%s")
                 progname progname progname
                 tramp-end-of-heredoc
                 (mapconcat 'identity dirlist "\n")
                 tramp-end-of-heredoc))
        (goto-char (point-max))
        (when (search-backward "tramp_executable " nil t)
          (skip-chars-forward "^ ")
          (skip-chars-forward " ")
          (setq result (buffer-substring (point) (point-at-eol)))))
    result)))

(defun tramp-set-remote-path (vec)
  "Sets the remote environment PATH to existing directories.
I.e., for each directory in `tramp-remote-path', it is tested
whether it exists and if so, it is added to the environment
variable PATH."
  (tramp-message vec 5 "Setting $PATH environment variable")
  (tramp-send-command
   vec (format "PATH=%s; export PATH"
               (mapconcat 'identity (tramp-get-remote-path vec) ":"))))

;; ------------------------------------------------------------
;; -- Communication with external shell --
;; ------------------------------------------------------------

(defun tramp-find-file-exists-command (vec)
  "Find a command on the remote host for checking if a file exists.
Here, we are looking for a command which has zero exit status if the
file exists and nonzero exit status otherwise."
  (let ((existing "/")
        (nonexistent
         (tramp-shell-quote-argument "/ this file does not exist "))
        result)
    ;; The algorithm is as follows: we try a list of several commands.
    ;; For each command, we first run `$cmd /' -- this should return
    ;; true, as the root directory always exists.  And then we run
    ;; `$cmd /this\ file\ does\ not\ exist ', hoping that the file indeed
    ;; does not exist.  This should return false.  We use the first
    ;; command we find that seems to work.
    ;; The list of commands to try is as follows:
    ;; `ls -d'            This works on most systems, but NetBSD 1.4
    ;;                    has a bug: `ls' always returns zero exit
    ;;                    status, even for files which don't exist.
    ;; `test -e'          Some Bourne shells have a `test' builtin
    ;;                    which does not know the `-e' option.
    ;; `/bin/test -e'     For those, the `test' binary on disk normally
    ;;                    provides the option.  Alas, the binary
    ;;                    is sometimes `/bin/test' and sometimes it's
    ;;                    `/usr/bin/test'.
    ;; `/usr/bin/test -e' In case `/bin/test' does not exist.
    (unless (or
             (ignore-errors
               (and (setq result (format "%s -e" (tramp-get-test-command vec)))
                    (tramp-send-command-and-check
                     vec (format "%s %s" result existing))
                    (not (tramp-send-command-and-check
                          vec (format "%s %s" result nonexistent)))))
             (ignore-errors
               (and (setq result "/bin/test -e")
                    (tramp-send-command-and-check
                     vec (format "%s %s" result existing))
                    (not (tramp-send-command-and-check
                          vec (format "%s %s" result nonexistent)))))
             (ignore-errors
               (and (setq result "/usr/bin/test -e")
                    (tramp-send-command-and-check
                     vec (format "%s %s" result existing))
                    (not (tramp-send-command-and-check
                          vec (format "%s %s" result nonexistent)))))
             (ignore-errors
               (and (setq result (format "%s -d" (tramp-get-ls-command vec)))
                    (tramp-send-command-and-check
                     vec (format "%s %s" result existing))
                    (not (tramp-send-command-and-check
                          vec (format "%s %s" result nonexistent))))))
      (tramp-error
       vec 'file-error "Couldn't find command to check if file exists"))
    result))

(defun tramp-open-shell (vec shell)
  "Opens shell SHELL."
  (with-tramp-progress-reporter
      vec 5 (format-message "Opening remote shell `%s'" shell)
    ;; Find arguments for this shell.
    (let ((alist tramp-sh-extra-args)
          item extra-args)
      (while (and alist (null extra-args))
        (setq item (pop alist))
        (when (string-match (car item) shell)
          (setq extra-args (cdr item))))
      ;; It is useful to set the prompt in the following command
      ;; because some people have a setting for $PS1 which /bin/sh
      ;; doesn't know about and thus /bin/sh will display a strange
      ;; prompt.  For example, if $PS1 has "${CWD}" in the value, then
      ;; ksh will display the current working directory but /bin/sh
      ;; will display a dollar sign.  The following command line sets
      ;; $PS1 to a sane value, and works under Bourne-ish shells as
      ;; well as csh-like shells.  We also unset the variable $ENV
      ;; because that is read by some sh implementations (eg, bash
      ;; when called as sh) on startup; this way, we avoid the startup
      ;; file clobbering $PS1.  $PROMPT_COMMAND is another way to set
      ;; the prompt in /bin/bash, it must be discarded as well.
      ;; $HISTFILE is set according to `tramp-histfile-override'.
      (tramp-send-command
       vec (format
            "exec env ENV='' %s PROMPT_COMMAND='' PS1=%s PS2='' PS3='' %s %s"
            (if (stringp tramp-histfile-override)
                (format "HISTFILE=%s"
                        (tramp-shell-quote-argument tramp-histfile-override))
              (if tramp-histfile-override
                  "HISTFILE='' HISTFILESIZE=0 HISTSIZE=0"
                ""))
            (tramp-shell-quote-argument tramp-end-of-output)
            shell (or extra-args ""))
       t))
    (tramp-set-connection-property
     (tramp-get-connection-process vec) "remote-shell" shell)))

(defun tramp-find-shell (vec)
  "Opens a shell on the remote host which groks tilde expansion."
  (with-current-buffer (tramp-get-buffer vec)
    (let ((default-shell (tramp-get-method-parameter vec 'tramp-remote-shell))
          shell)
      (setq shell
            (with-tramp-connection-property vec "remote-shell"
              ;; CCC: "root" does not exist always, see my QNAP TS-459.
              ;; Which check could we apply instead?
              (tramp-send-command vec "echo ~root" t)
              (if (or (string-match "^~root$" (buffer-string))
                      ;; The default shell (ksh93) of OpenSolaris and
                      ;; Solaris is buggy.  We've got reports for
                      ;; "SunOS 5.10" and "SunOS 5.11" so far.
                      (string-match (regexp-opt '("SunOS 5.10" "SunOS 5.11"))
                                    (tramp-get-connection-property
                                     vec "uname" "")))

                  (or (tramp-find-executable
                       vec "bash" (tramp-get-remote-path vec) t t)
                      (tramp-find-executable
                       vec "ksh" (tramp-get-remote-path vec) t t)
                      ;; Maybe it works at least for some other commands.
                      (prog1
                          default-shell
                        (tramp-message
                         vec 2
                         (concat
                          "Couldn't find a remote shell which groks tilde "
                          "expansion, using `%s'")
                         default-shell)))

                default-shell)))

      ;; Open a new shell if needed.
      (unless (string-equal shell default-shell)
        (tramp-message
         vec 5 "Starting remote shell `%s' for tilde expansion" shell)
        (tramp-open-shell vec shell)))))

;; Utility functions.

(defun tramp-barf-if-no-shell-prompt (proc timeout &rest error-args)
  "Wait for shell prompt and barf if none appears.
Looks at process PROC to see if a shell prompt appears in TIMEOUT
seconds.  If not, it produces an error message with the given ERROR-ARGS."
  (let ((vec (tramp-get-connection-property proc "vector" nil)))
    (condition-case nil
        (tramp-wait-for-regexp
         proc timeout
         (format
          "\\(%s\\|%s\\)\\'" shell-prompt-pattern tramp-shell-prompt-pattern))
      (error
       (delete-process proc)
       (apply 'tramp-error-with-buffer
              (tramp-get-connection-buffer vec) vec 'file-error error-args)))))

(defun tramp-open-connection-setup-interactive-shell (proc vec)
  "Set up an interactive shell.
Mainly sets the prompt and the echo correctly.  PROC is the shell
process to set up.  VEC specifies the connection."
  (let ((tramp-end-of-output tramp-initial-end-of-output)
        (case-fold-search t))
    (tramp-open-shell vec (tramp-get-method-parameter vec 'tramp-remote-shell))

    ;; Disable tab and echo expansion.
    (tramp-message vec 5 "Setting up remote shell environment")
    (tramp-send-command
     vec "stty tab0 -inlcr -onlcr -echo kill '^U' erase '^H'" t)
    ;; Check whether the echo has really been disabled.  Some
    ;; implementations, like busybox of embedded GNU/Linux, don't
    ;; support disabling.
    (tramp-send-command vec "echo foo" t)
    (with-current-buffer (process-buffer proc)
      (goto-char (point-min))
      (when (looking-at "echo foo")
        (tramp-set-connection-property proc "remote-echo" t)
        (tramp-message vec 5 "Remote echo still on. Ok.")
        ;; Make sure backspaces and their echo are enabled and no line
        ;; width magic interferes with them.
        (tramp-send-command vec "stty icanon erase ^H cols 32767" t))))

  (tramp-message vec 5 "Setting shell prompt")
  (tramp-send-command
   vec (format "PS1=%s PS2='' PS3='' PROMPT_COMMAND=''"
               (tramp-shell-quote-argument tramp-end-of-output)) t)

  ;; Check whether the output of "uname -sr" has been changed.  If
  ;; yes, this is a strong indication that we must expire all
  ;; connection properties.  We start again with
  ;; `tramp-maybe-open-connection', it will be caught there.
  (tramp-message vec 5 "Checking system information")
  (let ((old-uname (tramp-get-connection-property vec "uname" nil))
        (new-uname
         (tramp-set-connection-property
          vec "uname"
          (tramp-send-command-and-read vec "echo \\\"`uname -sr`\\\""))))
    (when (and (stringp old-uname) (not (string-equal old-uname new-uname)))
      (tramp-message
       vec 3
       "Connection reset, because remote host changed from `%s' to `%s'"
       old-uname new-uname)
      ;; We want to keep the password.
      (tramp-cleanup-connection vec t t)
      (throw 'uname-changed (tramp-maybe-open-connection vec))))

  ;; Try to set up the coding system correctly.
  ;; CCC this can't be the right way to do it.  Hm.
  (tramp-message vec 5 "Determining coding system")
  (with-current-buffer (process-buffer proc)
    ;; Use MULE to select the right EOL convention for communicating
    ;; with the process.
    (let ((cs (or (and (memq 'utf-8 (coding-system-list))
                       (string-match "utf-?8" (tramp-get-remote-locale vec))
                       (cons 'utf-8 'utf-8))
                  (process-coding-system proc)
                  (cons 'undecided 'undecided)))
          cs-decode cs-encode)
      (when (symbolp cs) (setq cs (cons cs cs)))
      (setq cs-decode (or (car cs) 'undecided)
            cs-encode (or (cdr cs) 'undecided)
            cs-encode
            (coding-system-change-eol-conversion
             cs-encode
             (if (string-match
                  "^Darwin" (tramp-get-connection-property vec "uname" ""))
                 'mac 'unix)))
      (tramp-send-command vec "echo foo ; echo bar" t)
      (goto-char (point-min))
      (when (search-forward "\r" nil t)
        (setq cs-decode (coding-system-change-eol-conversion cs-decode 'dos)))
      ;; Special setting for Mac OS X.
      (when (and (string-match
                  "^Darwin" (tramp-get-connection-property vec "uname" ""))
                 (memq 'utf-8-hfs (coding-system-list)))
        (setq cs-decode 'utf-8-hfs
              cs-encode 'utf-8-hfs))
      (set-buffer-process-coding-system cs-decode cs-encode)
      (tramp-message
       vec 5 "Setting coding system to `%s' and `%s'" cs-decode cs-encode)))

  (tramp-send-command vec "set +o vi +o emacs" t)

  ;; Check whether the remote host suffers from buggy
  ;; `send-process-string'.  This is known for FreeBSD (see comment in
  ;; `send_process', file process.c).  I've tested sending 624 bytes
  ;; successfully, sending 625 bytes failed.  Emacs makes a hack when
  ;; this host type is detected locally.  It cannot handle remote
  ;; hosts, though.
  (with-tramp-connection-property proc "chunksize"
    (cond
     ((and (integerp tramp-chunksize) (> tramp-chunksize 0))
      tramp-chunksize)
     (t
      (tramp-message
       vec 5 "Checking remote host type for `send-process-string' bug")
      (if (string-match
           "^FreeBSD" (tramp-get-connection-property vec "uname" ""))
          500 0))))

  ;; Set remote PATH variable.
  (tramp-set-remote-path vec)

  ;; Search for a good shell before searching for a command which
  ;; checks if a file exists.  This is done because Tramp wants to use
  ;; "test foo; echo $?" to check if various conditions hold, and
  ;; there are buggy /bin/sh implementations which don't execute the
  ;; "echo $?"  part if the "test" part has an error.  In particular,
  ;; the OpenSolaris /bin/sh is a problem.  There are also other
  ;; problems with /bin/sh of OpenSolaris, like redirection of stderr
  ;; in function declarations, or changing HISTFILE in place.
  ;; Therefore, OpenSolaris' /bin/sh is replaced by bash, when
  ;; detected.
  (tramp-find-shell vec)

  ;; Disable unexpected output.
  (tramp-send-command vec "mesg n 2>/dev/null; biff n 2>/dev/null" t)

  ;; IRIX64 bash expands "!" even when in single quotes.  This
  ;; destroys our shell functions, we must disable it.  See
  ;; <http://stackoverflow.com/questions/3291692/irix-bash-shell-expands-expression-in-single-quotes-yet-shouldnt>.
  (when (string-match "^IRIX64" (tramp-get-connection-property vec "uname" ""))
    (tramp-send-command vec "set +H" t))

  ;; On BSD-like systems, ?\t is expanded to spaces.  Suppress this.
  (when (string-match "BSD\\|Darwin"
                      (tramp-get-connection-property vec "uname" ""))
    (tramp-send-command vec "stty -oxtabs" t))

  ;; Set utf8 encoding.  Needed for Mac OS X, for example.  This is
  ;; non-POSIX, so we must expect errors on some systems.
  (tramp-send-command vec "stty iutf8 2>/dev/null" t)

  ;; Set `remote-tty' process property.
  (let ((tty (tramp-send-command-and-read vec "echo \\\"`tty`\\\"" 'noerror)))
    (unless (zerop (length tty))
      (process-put proc 'remote-tty tty)))

  ;; Dump stty settings in the traces.
  (when (>= tramp-verbose 9)
    (tramp-send-command vec "stty -a" t))

  ;; Set the environment.
  (tramp-message vec 5 "Setting default environment")

  (let ((env (append `(,(tramp-get-remote-locale vec))
                     (copy-sequence tramp-remote-process-environment)))
        unset vars item)
    (while env
      (setq item (split-string (car env) "=" 'omit))
      (setcdr item (mapconcat 'identity (cdr item) "="))
      (if (and (stringp (cdr item)) (not (string-equal (cdr item) "")))
          (push (format "%s %s" (car item) (cdr item)) vars)
        (push (car item) unset))
      (setq env (cdr env)))
    (when vars
      (tramp-send-command
       vec
       (format "while read var val; do export $var=$val; done <<'%s'\n%s\n%s"
               tramp-end-of-heredoc
               (mapconcat 'identity vars "\n")
               tramp-end-of-heredoc)
       t))
    (when unset
      (tramp-send-command
       vec (format "unset %s" (mapconcat 'identity unset " ")) t))))

;; Old text from documentation of tramp-methods:
;; Using a uuencode/uudecode inline method is discouraged, please use one
;; of the base64 methods instead since base64 encoding is much more
;; reliable and the commands are more standardized between the different
;; Unix versions.  But if you can't use base64 for some reason, please
;; note that the default uudecode command does not work well for some
;; Unices, in particular AIX and Irix.  For AIX, you might want to use
;; the following command for uudecode:
;;
;;     sed '/^begin/d;/^[` ]$/d;/^end/d' | iconv -f uucode -t ISO8859-1
;;
;; For Irix, no solution is known yet.

(autoload 'uudecode-decode-region "uudecode")

(defconst tramp-local-coding-commands
  `((b64 base64-encode-region base64-decode-region)
    (uu  tramp-uuencode-region uudecode-decode-region)
    (pack ,(format tramp-perl-pack "perl") ,(format tramp-perl-unpack "perl")))
  "List of local coding commands for inline transfer.
Each item is a list that looks like this:

\(FORMAT ENCODING DECODING)

FORMAT is  symbol describing the encoding/decoding format.  It can be
`b64' for base64 encoding, `uu' for uu encoding, or `pack' for simple packing.

ENCODING and DECODING can be strings, giving commands, or symbols,
giving functions.  If they are strings, then they can contain
the \"%s\" format specifier.  If that specifier is present, the input
file name will be put into the command line at that spot.  If the
specifier is not present, the input should be read from standard
input.

If they are functions, they will be called with two arguments, start
and end of region, and are expected to replace the region contents
with the encoded or decoded results, respectively.")

(defconst tramp-remote-coding-commands
  `((b64 "base64" "base64 -d -i")
    ;; "-i" is more robust with older base64 from GNU coreutils.
    ;; However, I don't know whether all base64 versions do supports
    ;; this option.
    (b64 "base64" "base64 -d")
    (b64 "openssl enc -base64" "openssl enc -d -base64")
    (b64 "mimencode -b" "mimencode -u -b")
    (b64 "mmencode -b" "mmencode -u -b")
    (b64 "recode data..base64" "recode base64..data")
    (b64 tramp-perl-encode-with-module tramp-perl-decode-with-module)
    (b64 tramp-perl-encode tramp-perl-decode)
    ;; This is painful slow, so we put it on the end.
    (b64 tramp-awk-encode tramp-awk-decode ,tramp-awk-coding-test)
    (uu  "uuencode xxx" "uudecode -o /dev/stdout" "test -c /dev/stdout")
    (uu  "uuencode xxx" "uudecode -o -")
    (uu  "uuencode xxx" "uudecode -p")
    (uu  "uuencode xxx" tramp-uudecode)
    (pack tramp-perl-pack tramp-perl-unpack))
  "List of remote coding commands for inline transfer.
Each item is a list that looks like this:

\(FORMAT ENCODING DECODING [TEST])

FORMAT is a symbol describing the encoding/decoding format.  It can be
`b64' for base64 encoding, `uu' for uu encoding, or `pack' for simple packing.

ENCODING and DECODING can be strings, giving commands, or symbols,
giving variables.  If they are strings, then they can contain
the \"%s\" format specifier.  If that specifier is present, the input
file name will be put into the command line at that spot.  If the
specifier is not present, the input should be read from standard
input.

If they are variables, this variable is a string containing a
Perl or Shell implementation for this functionality.  This
program will be transferred to the remote host, and it is
available as shell function with the same name.  A \"%t\" format
specifier in the variable value denotes a temporary file.

The optional TEST command can be used for further tests, whether
ENCODING and DECODING are applicable.")

(defun tramp-find-inline-encoding (vec)
  "Find an inline transfer encoding that works.
Goes through the list `tramp-local-coding-commands' and
`tramp-remote-coding-commands'."
  (save-excursion
    (let ((local-commands tramp-local-coding-commands)
          (magic "xyzzy")
          (p (tramp-get-connection-process vec))
          loc-enc loc-dec rem-enc rem-dec rem-test litem ritem found)
      (while (and local-commands (not found))
        (setq litem (pop local-commands))
        (catch 'wont-work-local
          (let ((format (nth 0 litem))
                (remote-commands tramp-remote-coding-commands))
            (setq loc-enc (nth 1 litem))
            (setq loc-dec (nth 2 litem))
            ;; If the local encoder or decoder is a string, the
            ;; corresponding command has to work locally.
            (if (not (stringp loc-enc))
                (tramp-message
                 vec 5 "Checking local encoding function `%s'" loc-enc)
              (tramp-message
               vec 5 "Checking local encoding command `%s' for sanity" loc-enc)
              (unless (zerop (tramp-call-local-coding-command
                              loc-enc nil nil))
                (throw 'wont-work-local nil)))
            (if (not (stringp loc-dec))
                (tramp-message
                 vec 5 "Checking local decoding function `%s'" loc-dec)
              (tramp-message
               vec 5 "Checking local decoding command `%s' for sanity" loc-dec)
              (unless (zerop (tramp-call-local-coding-command
                              loc-dec nil nil))
                (throw 'wont-work-local nil)))
            ;; Search for remote coding commands with the same format
            (while (and remote-commands (not found))
              (setq ritem (pop remote-commands))
              (catch 'wont-work-remote
                (when (equal format (nth 0 ritem))
                  (setq rem-enc (nth 1 ritem))
                  (setq rem-dec (nth 2 ritem))
                  (setq rem-test (nth 3 ritem))
                  ;; Check the remote test command if exists.
                  (when (stringp rem-test)
                    (tramp-message
                     vec 5 "Checking remote test command `%s'" rem-test)
                    (unless (tramp-send-command-and-check vec rem-test t)
                      (throw 'wont-work-remote nil)))
                  ;; Check if remote perl exists when necessary.
                  (when (and (symbolp rem-enc)
                             (string-match "perl" (symbol-name rem-enc))
                             (not (tramp-get-remote-perl vec)))
                    (throw 'wont-work-remote nil))
                  ;; Check if remote encoding and decoding commands can be
                  ;; called remotely with null input and output.  This makes
                  ;; sure there are no syntax errors and the command is really
                  ;; found.  Note that we do not redirect stdout to /dev/null,
                  ;; for two reasons: when checking the decoding command, we
                  ;; actually check the output it gives.  And also, when
                  ;; redirecting "mimencode" output to /dev/null, then as root
                  ;; it might change the permissions of /dev/null!
                  (when (not (stringp rem-enc))
                    (let ((name (symbol-name rem-enc)))
                      (while (string-match (regexp-quote "-") name)
                        (setq name (replace-match "_" nil t name)))
                      (tramp-maybe-send-script vec (symbol-value rem-enc) name)
                      (setq rem-enc name)))
                  (tramp-message
                   vec 5
                   "Checking remote encoding command `%s' for sanity" rem-enc)
                  (unless (tramp-send-command-and-check
                           vec (format "%s </dev/null" rem-enc) t)
                    (throw 'wont-work-remote nil))

                  (when (not (stringp rem-dec))
                    (let ((name (symbol-name rem-dec))
                          (value (symbol-value rem-dec))
                          tmpfile)
                      (while (string-match (regexp-quote "-") name)
                        (setq name (replace-match "_" nil t name)))
                      (when (string-match "\\(^\\|[^%]\\)%t" value)
                        (setq tmpfile
                              (make-temp-name
                               (expand-file-name
                                tramp-temp-name-prefix
                                (tramp-get-remote-tmpdir vec)))
                              value
                              (format-spec
                               value
                               (format-spec-make
                                ?t
                                (file-remote-p tmpfile 'localname)))))
                      (tramp-maybe-send-script vec value name)
                      (setq rem-dec name)))
                  (tramp-message
                   vec 5
                   "Checking remote decoding command `%s' for sanity" rem-dec)
                  (unless (tramp-send-command-and-check
                           vec
                           (format "echo %s | %s | %s" magic rem-enc rem-dec)
                           t)
                    (throw 'wont-work-remote nil))

                  (with-current-buffer (tramp-get-buffer vec)
                    (goto-char (point-min))
                    (unless (looking-at (regexp-quote magic))
                      (throw 'wont-work-remote nil)))

                  ;; `rem-enc' and `rem-dec' could be a string meanwhile.
                  (setq rem-enc (nth 1 ritem))
                  (setq rem-dec (nth 2 ritem))
                  (setq found t)))))))

      (when found
        ;; Set connection properties.  Since the commands are risky
        ;; (due to output direction), we cache them in the process cache.
        (tramp-message vec 5 "Using local encoding `%s'" loc-enc)
        (tramp-set-connection-property p "local-encoding" loc-enc)
        (tramp-message vec 5 "Using local decoding `%s'" loc-dec)
        (tramp-set-connection-property p "local-decoding" loc-dec)
        (tramp-message vec 5 "Using remote encoding `%s'" rem-enc)
        (tramp-set-connection-property p "remote-encoding" rem-enc)
        (tramp-message vec 5 "Using remote decoding `%s'" rem-dec)
        (tramp-set-connection-property p "remote-decoding" rem-dec)))))

(defun tramp-call-local-coding-command (cmd input output)
  "Call the local encoding or decoding command.
If CMD contains \"%s\", provide input file INPUT there in command.
Otherwise, INPUT is passed via standard input.
INPUT can also be nil which means `/dev/null'.
OUTPUT can be a string (which specifies a file name), or t (which
means standard output and thus the current buffer), or nil (which
means discard it)."
  (tramp-call-process
   nil tramp-encoding-shell
   (when (and input (not (string-match "%s" cmd))) input)
   (if (eq output t) t nil)
   nil
   tramp-encoding-command-switch
   (concat
    (if (string-match "%s" cmd) (format cmd input) cmd)
    (if (stringp output) (concat " >" output) ""))))

(defconst tramp-inline-compress-commands
  '(("gzip" "gzip -d")
    ("bzip2" "bzip2 -d")
    ("xz" "xz -d")
    ("compress" "compress -d"))
  "List of compress and decompress commands for inline transfer.
Each item is a list that looks like this:

\(COMPRESS DECOMPRESS)

COMPRESS or DECOMPRESS are strings with the respective commands.")

(defun tramp-find-inline-compress (vec)
  "Find an inline transfer compress command that works.
Goes through the list `tramp-inline-compress-commands'."
  (save-excursion
    (let ((commands tramp-inline-compress-commands)
          (magic "xyzzy")
          (p (tramp-get-connection-process vec))
          item compress decompress found)
      (while (and commands (not found))
        (catch 'next
          (setq item (pop commands)
                compress (nth 0 item)
                decompress (nth 1 item))
          (tramp-message
           vec 5
           "Checking local compress commands `%s', `%s' for sanity"
           compress decompress)
          (unless
              (zerop
               (tramp-call-local-coding-command
                (format
                 ;; Windows shells need the program file name after
                 ;; the pipe symbol be quoted if they use forward
                 ;; slashes as directory separators.
                 (if (memq system-type '(windows-nt))
                     "echo %s | \"%s\" | \"%s\""
                   "echo %s | %s | %s")
                 magic compress decompress) nil nil))
            (throw 'next nil))
          (tramp-message
           vec 5
           "Checking remote compress commands `%s', `%s' for sanity"
           compress decompress)
          (unless (tramp-send-command-and-check
                   vec (format "echo %s | %s | %s" magic compress decompress) t)
            (throw 'next nil))
          (setq found t)))

      ;; Did we find something?
      (if found
          (progn
            ;; Set connection properties.  Since the commands are
            ;; risky (due to output direction), we cache them in the
            ;; process cache.
            (tramp-message
             vec 5 "Using inline transfer compress command `%s'" compress)
            (tramp-set-connection-property p "inline-compress" compress)
            (tramp-message
             vec 5 "Using inline transfer decompress command `%s'" decompress)
            (tramp-set-connection-property p "inline-decompress" decompress))

        (tramp-set-connection-property p "inline-compress" nil)
        (tramp-set-connection-property p "inline-decompress" nil)
        (tramp-message
         vec 2 "Couldn't find an inline transfer compress command")))))

(defun tramp-compute-multi-hops (vec)
  "Expands VEC according to `tramp-default-proxies-alist'.
Gateway hops are already opened."
  (let ((target-alist `(,vec))
        (hops (or (tramp-file-name-hop vec) ""))
        (item vec)
        choices proxy)

    ;; Ad-hoc proxy definitions.
    (dolist (proxy (reverse (split-string hops tramp-postfix-hop-regexp 'omit)))
      (let ((user (tramp-file-name-user item))
            (host (tramp-file-name-host item))
            (proxy (concat
                    tramp-prefix-format proxy tramp-postfix-host-format)))
        (tramp-message
         vec 5 "Add proxy (\"%s\" \"%s\" \"%s\")"
         (and (stringp host) (regexp-quote host))
         (and (stringp user) (regexp-quote user))
         proxy)
        ;; Add the hop.
        (add-to-list
         'tramp-default-proxies-alist
         (list (and (stringp host) (regexp-quote host))
               (and (stringp user) (regexp-quote user))
               proxy))
        (setq item (tramp-dissect-file-name proxy))))
    ;; Save the new value.
    (when (and hops tramp-save-ad-hoc-proxies)
      (customize-save-variable
       'tramp-default-proxies-alist tramp-default-proxies-alist))

    ;; Look for proxy hosts to be passed.
    (setq choices tramp-default-proxies-alist)
    (while choices
      (setq item (pop choices)
            proxy (eval (nth 2 item)))
      (when (and
             ;; Host.
             (string-match (or (eval (nth 0 item)) "")
                           (or (tramp-file-name-host (car target-alist)) ""))
             ;; User.
             (string-match (or (eval (nth 1 item)) "")
                           (or (tramp-file-name-user (car target-alist)) "")))
        (if (null proxy)
            ;; No more hops needed.
            (setq choices nil)
          ;; Replace placeholders.
          (setq proxy
                (format-spec
                 proxy
                 (format-spec-make
                  ?u (or (tramp-file-name-user (car target-alist)) "")
                  ?h (or (tramp-file-name-host (car target-alist)) ""))))
          (with-parsed-tramp-file-name proxy l
            ;; Add the hop.
            (push l target-alist)
            ;; Start next search.
            (setq choices tramp-default-proxies-alist)))))

    ;; Handle gateways.
    (when (and (boundp 'tramp-gw-tunnel-method) (boundp 'tramp-gw-socks-method)
               (string-match
                (format
                 "^\\(%s\\|%s\\)$" tramp-gw-tunnel-method tramp-gw-socks-method)
                (tramp-file-name-method (car target-alist))))
      (let ((gw (pop target-alist))
            (hop (pop target-alist)))
        ;; Is the method prepared for gateways?
        (unless (tramp-file-name-port hop)
          (tramp-error
           vec 'file-error
           "Connection `%s' is not supported for gateway access." hop))
        ;; Open the gateway connection.
        (push
         (vector
          (tramp-file-name-method hop) (tramp-file-name-user hop)
          (tramp-gw-open-connection vec gw hop) nil nil)
         target-alist)
        ;; For the password prompt, we need the correct values.
        ;; Therefore, we must remember the gateway vector.  But we
        ;; cannot do it as connection property, because it shouldn't
        ;; be persistent.  And we have no started process yet either.
        (let ((tramp-verbose 0))
          (tramp-set-file-property (car target-alist) "" "gateway" hop))))

    ;; Foreign and out-of-band methods are not supported for multi-hops.
    (when (cdr target-alist)
      (setq choices target-alist)
      (while (setq item (pop choices))
        (when (or (not (tramp-get-method-parameter item 'tramp-login-program))
                  (tramp-get-method-parameter item 'tramp-copy-program))
          (tramp-error
           vec 'file-error
           "Method `%s' is not supported for multi-hops."
           (tramp-file-name-method item)))))

    ;; In case the host name is not used for the remote shell
    ;; command, the user could be misguided by applying a random
    ;; host name.
    (let* ((v (car target-alist))
           (method (tramp-file-name-method v))
           (host (tramp-file-name-host v)))
      (unless
          (or
           ;; There are multi-hops.
           (cdr target-alist)
           ;; The host name is used for the remote shell command.
           (member '("%h") (tramp-get-method-parameter v 'tramp-login-args))
           ;; The host is local.  We cannot use `tramp-local-host-p'
           ;; here, because it opens a connection as well.
           (string-match tramp-local-host-regexp host))
        (tramp-error
         v 'file-error
         "Host `%s' looks like a remote host, `%s' can only use the local host"
         host method)))

    ;; Result.
    target-alist))

(defun tramp-ssh-controlmaster-options (vec)
  "Return the Control* arguments of the local ssh."
  (cond
   ;; No options to be computed.
   ((or (null tramp-use-ssh-controlmaster-options)
        (null (assoc "%c" (tramp-get-method-parameter vec 'tramp-login-args))))
    "")

   ;; There is already a value to be used.
   ((stringp tramp-ssh-controlmaster-options) tramp-ssh-controlmaster-options)

   ;; Determine the options.
   (t (setq tramp-ssh-controlmaster-options "")
      (let ((case-fold-search t))
        (ignore-errors
          (when (executable-find "ssh")
            (with-temp-buffer
              (tramp-call-process vec "ssh" nil t nil "-o" "ControlMaster")
              (goto-char (point-min))
              (when (search-forward-regexp "missing.+argument" nil t)
                (setq tramp-ssh-controlmaster-options "-o ControlMaster=auto")))
            (unless (zerop (length tramp-ssh-controlmaster-options))
              (with-temp-buffer
                ;; We use a non-existing IP address, in order to avoid
                ;; useless connections, and DNS timeouts.
                (tramp-call-process
                 vec "ssh" nil t nil "-o" "ControlPath=%C" "0.0.0.1")
                (goto-char (point-min))
                (setq tramp-ssh-controlmaster-options
                      (concat tramp-ssh-controlmaster-options
                              (if (search-forward-regexp "unknown.+key" nil t)
                                  " -o ControlPath='tramp.%%r@%%h:%%p'"
                                " -o ControlPath='tramp.%%C'"))))
              (with-temp-buffer
                (tramp-call-process vec "ssh" nil t nil "-o" "ControlPersist")
                (goto-char (point-min))
                (when (search-forward-regexp "missing.+argument" nil t)
                  (setq tramp-ssh-controlmaster-options
                        (concat tramp-ssh-controlmaster-options
                                " -o ControlPersist=no"))))))))
      tramp-ssh-controlmaster-options)))

(defun tramp-maybe-open-connection (vec)
  "Maybe open a connection VEC.
Does not do anything if a connection is already open, but re-opens the
connection if a previous connection has died for some reason."
  (tramp-check-proper-method-and-host vec)

  (let ((p (tramp-get-connection-process vec))
        (process-name (tramp-get-connection-property vec "process-name" nil))
        (process-environment (copy-sequence process-environment))
        (pos (with-current-buffer (tramp-get-connection-buffer vec) (point))))

    ;; If Tramp opens the same connection within a short time frame,
    ;; there is a problem.  We shall signal this.
    (unless (or (and p (processp p) (memq (process-status p) '(run open)))
                (not (equal (butlast (append vec nil) 2)
                            (car tramp-current-connection)))
                (> (tramp-time-diff
                    (current-time) (cdr tramp-current-connection))
                   (or tramp-connection-min-time-diff 0)))
      (throw 'suppress 'suppress))

    ;; If too much time has passed since last command was sent, look
    ;; whether process is still alive.  If it isn't, kill it.  When
    ;; using ssh, it can sometimes happen that the remote end has hung
    ;; up but the local ssh client doesn't recognize this until it
    ;; tries to send some data to the remote end.  So that's why we
    ;; try to send a command from time to time, then look again
    ;; whether the process is really alive.
    (condition-case nil
        (when (and (> (tramp-time-diff
                       (current-time)
                       (tramp-get-connection-property
                        p "last-cmd-time" '(0 0 0)))
                      60)
                   p (processp p) (memq (process-status p) '(run open)))
          (tramp-send-command vec "echo are you awake" t t)
          (unless (and (memq (process-status p) '(run open))
                       (tramp-wait-for-output p 10))
            ;; The error will be caught locally.
            (tramp-error vec 'file-error "Awake did fail")))
      (file-error
       (tramp-cleanup-connection vec t)
       (setq p nil)))

    ;; New connection must be opened.
    (condition-case err
        (unless (and p (processp p) (memq (process-status p) '(run open)))

          ;; If `non-essential' is non-nil, don't reopen a new connection.
          ;; This variable has been introduced with Emacs 24.1.
          (when (and (boundp 'non-essential) (symbol-value 'non-essential))
            (throw 'non-essential 'non-essential))

          (with-tramp-progress-reporter
              vec 3
              (if (zerop (length (tramp-file-name-user vec)))
                  (format "Opening connection for %s using %s"
                          (tramp-file-name-host vec)
                          (tramp-file-name-method vec))
                (format "Opening connection for %s@%s using %s"
                        (tramp-file-name-user vec)
                        (tramp-file-name-host vec)
                        (tramp-file-name-method vec)))

            (catch 'uname-changed
              ;; Start new process.
              (when (and p (processp p))
                (delete-process p))
              (setenv "TERM" tramp-terminal-type)
              (setenv "LC_ALL" (tramp-get-local-locale vec))
              (if (stringp tramp-histfile-override)
                  (setenv "HISTFILE" tramp-histfile-override)
                (if tramp-histfile-override
                    (progn
                      (setenv "HISTFILE")
                      (setenv "HISTFILESIZE" "0")
                      (setenv "HISTSIZE" "0"))))
              (setenv "PROMPT_COMMAND")
              (setenv "PS1" tramp-initial-end-of-output)
              (unless (stringp tramp-encoding-shell)
                (tramp-error vec 'file-error "`tramp-encoding-shell' not set"))
              (let* ((target-alist (tramp-compute-multi-hops vec))
                     ;; We will apply `tramp-ssh-controlmaster-options'
                     ;; only for the first hop.
                     (options (tramp-ssh-controlmaster-options vec))
                     (process-connection-type tramp-process-connection-type)
                     (process-adaptive-read-buffering nil)
                     ;; There are unfortunate settings for "cmdproxy" on
                     ;; W32 systems.
                     (process-coding-system-alist nil)
                     (coding-system-for-read nil)
                     ;; This must be done in order to avoid our file
                     ;; name handler.
                     (p (let ((default-directory
                                (tramp-compat-temporary-file-directory)))
                          (apply
                           'start-process
                           (tramp-get-connection-name vec)
                           (tramp-get-connection-buffer vec)
                           (if tramp-encoding-command-interactive
                               (list tramp-encoding-shell
                                     tramp-encoding-command-interactive)
                             (list tramp-encoding-shell))))))

                ;; Set sentinel and query flag.
                (tramp-set-connection-property p "vector" vec)
                (set-process-sentinel p 'tramp-process-sentinel)
                (set-process-query-on-exit-flag p nil)
                (setq tramp-current-connection
                      (cons (butlast (append vec nil) 2) (current-time))
                      tramp-current-host (system-name))

                (tramp-message
                 vec 6 "%s" (mapconcat 'identity (process-command p) " "))

                ;; Check whether process is alive.
                (tramp-barf-if-no-shell-prompt
                 p 10
                 "Couldn't find local shell prompt for %s" tramp-encoding-shell)

                ;; Now do all the connections as specified.
                (while target-alist
                  (let* ((hop (car target-alist))
                         (l-method (tramp-file-name-method hop))
                         (l-user (tramp-file-name-user hop))
                         (l-host (tramp-file-name-host hop))
                         (l-port nil)
                         (login-program
                          (tramp-get-method-parameter hop 'tramp-login-program))
                         (login-args
                          (tramp-get-method-parameter hop 'tramp-login-args))
                         (login-env
                          (tramp-get-method-parameter hop 'tramp-login-env))
                         (async-args
                          (tramp-get-method-parameter hop 'tramp-async-args))
                         (connection-timeout
                          (tramp-get-method-parameter
                           hop 'tramp-connection-timeout))
                         (gw-args
                          (tramp-get-method-parameter hop 'tramp-gw-args))
                         (gw (let ((tramp-verbose 0))
                               (tramp-get-file-property hop "" "gateway" nil)))
                         (g-method (and gw (tramp-file-name-method gw)))
                         (g-user (and gw (tramp-file-name-user gw)))
                         (g-host (and gw (tramp-file-name-real-host gw)))
                         (command login-program)
                         ;; We don't create the temporary file.  In
                         ;; fact, it is just a prefix for the
                         ;; ControlPath option of ssh; the real
                         ;; temporary file has another name, and it is
                         ;; created and protected by ssh.  It is also
                         ;; removed by ssh when the connection is
                         ;; closed.  The temporary file name is cached
                         ;; in the main connection process, therefore
                         ;; we cannot use `tramp-get-connection-process'.
                         (tmpfile
                          (with-tramp-connection-property
                              (get-process (tramp-buffer-name vec)) "temp-file"
                            (make-temp-name
                             (expand-file-name
                              tramp-temp-name-prefix
                              (tramp-compat-temporary-file-directory)))))
                         spec r-shell)

                    ;; Add arguments for asynchronous processes.
                    (when (and process-name async-args)
                      (setq login-args (append async-args login-args)))

                    ;; Add gateway arguments if necessary.
                    (when gw
                      (tramp-set-connection-property p "gateway" t)
                      (when gw-args
                        (setq login-args (append gw-args login-args))))

                    ;; Check for port number.  Until now, there's no
                    ;; need for handling like method, user, host.
                    (when (string-match tramp-host-with-port-regexp l-host)
                      (setq l-port (match-string 2 l-host)
                            l-host (match-string 1 l-host)))

                    ;; Check, whether there is a restricted shell.
                    (dolist (elt tramp-restricted-shell-hosts-alist)
                      (when (string-match elt tramp-current-host)
                        (setq r-shell t)))

                    ;; Set variables for computing the prompt for
                    ;; reading password.  They can also be derived
                    ;; from a gateway.
                    (setq tramp-current-method (or g-method l-method)
                          tramp-current-user   (or g-user   l-user)
                          tramp-current-host   (or g-host   l-host))

                    ;; Add login environment.
                    (when login-env
                      (setq
                       login-env
                       (mapcar
                        (lambda (x)
                          (setq x (mapcar (lambda (y) (format-spec y spec)) x))
                          (unless (member "" x) (mapconcat 'identity x " ")))
                        login-env))
                      (while login-env
                        (setq command
                              (format
                               "%s=%s %s"
                               (pop login-env)
                               (tramp-shell-quote-argument (pop login-env))
                               command)))
                      (setq command (concat "env " command)))

                    ;; Replace `login-args' place holders.
                    (setq
                     l-host (or l-host "")
                     l-user (or l-user "")
                     l-port (or l-port "")
                     spec (format-spec-make ?t tmpfile)
                     options (format-spec options spec)
                     spec (format-spec-make
                           ?h l-host ?u l-user ?p l-port ?c options)
                     command
                     (concat
                      ;; We do not want to see the trailing local
                      ;; prompt in `start-file-process'.
                      (unless r-shell "exec ")
                      command " "
                      (mapconcat
                       (lambda (x)
                         (setq x (mapcar (lambda (y) (format-spec y spec)) x))
                         (unless (member "" x) (mapconcat 'identity x " ")))
                       login-args " ")
                      ;; Local shell could be a Windows COMSPEC.  It
                      ;; doesn't know the ";" syntax, but we must exit
                      ;; always for `start-file-process'.  It could
                      ;; also be a restricted shell, which does not
                      ;; allow "exec".
                      (when r-shell " && exit || exit")))

                    ;; Send the command.
                    (tramp-message vec 3 "Sending command `%s'" command)
                    (tramp-send-command vec command t t)
                    (tramp-process-actions
                     p vec pos tramp-actions-before-shell
                     (or connection-timeout tramp-connection-timeout))
                    (tramp-message
                     vec 3 "Found remote shell prompt on `%s'" l-host))
                  ;; Next hop.
                  (setq options ""
                        target-alist (cdr target-alist)))

                ;; Make initial shell settings.
                (tramp-open-connection-setup-interactive-shell p vec)

                ;; Mark it as connected.
                (tramp-set-connection-property p "connected" t)))))

      ;; When the user did interrupt, we must cleanup.
      (quit
       (tramp-cleanup-connection vec t)
       ;; Propagate the quit signal.
       (signal (car err) (cdr err))))))

(defun tramp-send-command (vec command &optional neveropen nooutput)
  "Send the COMMAND to connection VEC.
Erases temporary buffer before sending the command.  If optional
arg NEVEROPEN is non-nil, never try to open the connection.  This
is meant to be used from `tramp-maybe-open-connection' only.  The
function waits for output unless NOOUTPUT is set."
  (unless neveropen (tramp-maybe-open-connection vec))
  (let ((p (tramp-get-connection-process vec)))
    (when (tramp-get-connection-property p "remote-echo" nil)
      ;; We mark the command string that it can be erased in the output buffer.
      (tramp-set-connection-property p "check-remote-echo" t)
      ;; If we put `tramp-echo-mark' after a trailing newline (which
      ;; is assumed to be unquoted) `tramp-send-string' doesn't see
      ;; that newline and adds `tramp-rsh-end-of-line' right after
      ;; `tramp-echo-mark', so the remote shell sees two consecutive
      ;; trailing line endings and sends two prompts after executing
      ;; the command, which confuses `tramp-wait-for-output'.
      (when (and (not (string= command ""))
                 (string-equal (substring command -1) "\n"))
        (setq command (substring command 0 -1)))
      ;; No need to restore a trailing newline here since `tramp-send-string'
      ;; makes sure that the string ends in `tramp-rsh-end-of-line', anyway.
      (setq command (format "%s%s%s" tramp-echo-mark command tramp-echo-mark)))
    ;; Send the command.
    (tramp-message vec 6 "%s" command)
    (tramp-send-string vec command)
    (unless nooutput (tramp-wait-for-output p))))

(defun tramp-wait-for-output (proc &optional timeout)
  "Wait for output from remote command."
  (unless (buffer-live-p (process-buffer proc))
    (delete-process proc)
    (tramp-error proc 'file-error "Process `%s' not available, try again" proc))
  (with-current-buffer (process-buffer proc)
    (let* (;; Initially, `tramp-end-of-output' is "#$ ".  There might
           ;; be leading escape sequences, which must be ignored.
           ;; Busyboxes built with the EDITING_ASK_TERMINAL config
           ;; option send also escape sequences, which must be
           ;; ignored.
           (regexp (format "[^#$\n]*%s\\(%s\\)?\r?$"
                           (regexp-quote tramp-end-of-output)
                           tramp-device-escape-sequence-regexp))
           ;; Sometimes, the commands do not return a newline but a
           ;; null byte before the shell prompt, for example "git
           ;; ls-files -c -z ...".
           (regexp1 (format "\\(^\\|\000\\)%s" regexp))
           (found (tramp-wait-for-regexp proc timeout regexp1)))
      (if found
          (let (buffer-read-only)
            ;; A simple-minded busybox has sent " ^H" sequences.
            ;; Delete them.
            (goto-char (point-min))
            (when (re-search-forward "^\\(.\b\\)+$" (point-at-eol) t)
              (forward-line 1)
              (delete-region (point-min) (point)))
            ;; Delete the prompt.
            (goto-char (point-max))
            (re-search-backward regexp nil t)
            (delete-region (point) (point-max)))
        (if timeout
            (tramp-error
             proc 'file-error
             "[[Remote prompt `%s' not found in %d secs]]"
             tramp-end-of-output timeout)
          (tramp-error
           proc 'file-error
           "[[Remote prompt `%s' not found]]" tramp-end-of-output)))
      ;; Return value is whether end-of-output sentinel was found.
      found)))

(defun tramp-send-command-and-check
  (vec command &optional subshell dont-suppress-err)
  "Run COMMAND and check its exit status.
Sends `echo $?' along with the COMMAND for checking the exit status.
If COMMAND is nil, just sends `echo $?'.  Returns t if the exit
status is 0, and nil otherwise.

If the optional argument SUBSHELL is non-nil, the command is
executed in a subshell, ie surrounded by parentheses.  If
DONT-SUPPRESS-ERR is non-nil, stderr won't be sent to /dev/null."
  (tramp-send-command
   vec
   (concat (if subshell "( " "")
           command
           (if command (if dont-suppress-err "; " " 2>/dev/null; ") "")
           "echo tramp_exit_status $?"
           (if subshell " )" "")))
  (with-current-buffer (tramp-get-connection-buffer vec)
    (goto-char (point-max))
    (unless (re-search-backward "tramp_exit_status [0-9]+" nil t)
      (tramp-error
       vec 'file-error "Couldn't find exit status of `%s'" command))
    (skip-chars-forward "^ ")
    (prog1
        (zerop (read (current-buffer)))
      (let (buffer-read-only)
        (delete-region (match-beginning 0) (point-max))))))

(defun tramp-barf-unless-okay (vec command fmt &rest args)
  "Run COMMAND, check exit status, throw error if exit status not okay.
Similar to `tramp-send-command-and-check' but accepts two more arguments
FMT and ARGS which are passed to `error'."
  (or (tramp-send-command-and-check vec command)
      (apply 'tramp-error vec 'file-error fmt args)))

(defun tramp-send-command-and-read (vec command &optional noerror marker)
  "Run COMMAND and return the output, which must be a Lisp expression.
If MARKER is a regexp, read the output after that string.
In case there is no valid Lisp expression and NOERROR is nil, it
raises an error."
  (when (if noerror
            (tramp-send-command-and-check vec command)
          (tramp-barf-unless-okay
           vec command "`%s' returns with error" command))
    (with-current-buffer (tramp-get-connection-buffer vec)
      (goto-char (point-min))
      ;; Read the marker.
      (when (stringp marker)
        (condition-case nil
            (re-search-forward marker)
          (error (unless noerror
                   (tramp-error
                    vec 'file-error
                    "`%s' does not return the marker `%s': `%s'"
                    command marker (buffer-string))))))
      ;; Read the expression.
      (condition-case nil
          (prog1 (read (current-buffer))
            ;; Error handling.
            (when (re-search-forward "\\S-" (point-at-eol) t)
              (error nil)))
        (error (unless noerror
                 (tramp-error
                  vec 'file-error
                  "`%s' does not return a valid Lisp expression: `%s'"
                  command (buffer-string))))))))

(defun tramp-convert-file-attributes (vec attr)
  "Convert `file-attributes' ATTR generated by perl script, stat or ls.
Convert file mode bits to string and set virtual device number.
Return ATTR."
  (when attr
    ;; Remove color escape sequences from symlink.
    (when (stringp (car attr))
      (while (string-match tramp-display-escape-sequence-regexp (car attr))
        (setcar attr (replace-match "" nil nil (car attr)))))
    ;; Convert uid and gid.  Use `tramp-unknown-id-integer' as
    ;; indication of unusable value.
    (when (and (numberp (nth 2 attr)) (< (nth 2 attr) 0))
      (setcar (nthcdr 2 attr) tramp-unknown-id-integer))
    (when (and (floatp (nth 2 attr))
               (<= (nth 2 attr) most-positive-fixnum))
      (setcar (nthcdr 2 attr) (round (nth 2 attr))))
    (when (and (numberp (nth 3 attr)) (< (nth 3 attr) 0))
      (setcar (nthcdr 3 attr) tramp-unknown-id-integer))
    (when (and (floatp (nth 3 attr))
               (<= (nth 3 attr) most-positive-fixnum))
      (setcar (nthcdr 3 attr) (round (nth 3 attr))))
    ;; Convert last access time.
    (unless (listp (nth 4 attr))
      (setcar (nthcdr 4 attr)
              (list (floor (nth 4 attr) 65536)
                    (floor (mod (nth 4 attr) 65536)))))
    ;; Convert last modification time.
    (unless (listp (nth 5 attr))
      (setcar (nthcdr 5 attr)
              (list (floor (nth 5 attr) 65536)
                    (floor (mod (nth 5 attr) 65536)))))
    ;; Convert last status change time.
    (unless (listp (nth 6 attr))
      (setcar (nthcdr 6 attr)
              (list (floor (nth 6 attr) 65536)
                    (floor (mod (nth 6 attr) 65536)))))
    ;; Convert file size.
    (when (< (nth 7 attr) 0)
      (setcar (nthcdr 7 attr) -1))
    (when (and (floatp (nth 7 attr))
               (<= (nth 7 attr) most-positive-fixnum))
      (setcar (nthcdr 7 attr) (round (nth 7 attr))))
    ;; Convert file mode bits to string.
    (unless (stringp (nth 8 attr))
      (setcar (nthcdr 8 attr) (tramp-file-mode-from-int (nth 8 attr)))
      (when (stringp (car attr))
        (aset (nth 8 attr) 0 ?l)))
    ;; Convert directory indication bit.
    (when (string-match "^d" (nth 8 attr))
      (setcar attr t))
    ;; Convert symlink from `tramp-do-file-attributes-with-stat'.
    (when (consp (car attr))
      (if (and (stringp (caar attr))
               (string-match ".+ -> .\\(.+\\)." (caar attr)))
          (setcar attr (match-string 1 (caar attr)))
        (setcar attr nil)))
    ;; Set file's gid change bit.
    (setcar (nthcdr 9 attr)
            (if (numberp (nth 3 attr))
                (not (= (nth 3 attr)
                        (tramp-get-remote-gid vec 'integer)))
              (not (string-equal
                    (nth 3 attr)
                    (tramp-get-remote-gid vec 'string)))))
    ;; Convert inode.
    (unless (listp (nth 10 attr))
      (setcar (nthcdr 10 attr)
              (condition-case nil
                  (cons (floor (nth 10 attr) 65536)
                        (floor (mod (nth 10 attr) 65536)))
                ;; Inodes can be incredible huge.  We must hide this.
                (error (tramp-get-inode vec)))))
    ;; Set virtual device number.
    (setcar (nthcdr 11 attr)
            (tramp-get-device vec))
    attr))

(defun tramp-shell-case-fold (string)
  "Converts STRING to shell glob pattern which ignores case."
  (mapconcat
   (lambda (c)
     (if (equal (downcase c) (upcase c))
         (vector c)
       (format "[%c%c]" (downcase c) (upcase c))))
   string
   ""))

(defun tramp-make-copy-program-file-name (vec)
  "Create a file name suitable for `scp', `pscp', or `nc' and workalikes."
  (let ((method (tramp-file-name-method vec))
        (user (tramp-file-name-user vec))
        (host (tramp-file-name-real-host vec))
        (localname (tramp-file-name-localname vec)))
    (when (string-match tramp-ipv6-regexp host)
      (setq host (format "[%s]" host)))
    (unless (string-match "ftp$" method)
      (setq localname (tramp-shell-quote-argument localname)))
    (cond
     ((tramp-get-method-parameter vec 'tramp-remote-copy-program)
      localname)
     ((not (zerop (length user)))
      (shell-quote-argument (format "%s@%s:%s" user host localname)))
     (t (shell-quote-argument (format "%s:%s" host localname))))))

(defun tramp-method-out-of-band-p (vec size)
  "Return t if this is an out-of-band method, nil otherwise."
  (and
   ;; It shall be an out-of-band method.
   (tramp-get-method-parameter vec 'tramp-copy-program)
   ;; There must be a size, otherwise the file doesn't exist.
   (numberp size)
   ;; Either the file size is large enough, or (in rare cases) there
   ;; does not exist a remote encoding.
   (or (null tramp-copy-size-limit)
       (> size tramp-copy-size-limit)
       (null (tramp-get-inline-coding vec "remote-encoding" size)))))

;; Variables local to connection.

(defun tramp-get-remote-path (vec)
  (with-tramp-connection-property
      ;; When `tramp-own-remote-path' is in `tramp-remote-path', we
      ;; cache the result for the session only.  Otherwise, the result
      ;; is cached persistently.
      (if (memq 'tramp-own-remote-path tramp-remote-path)
          (tramp-get-connection-process vec)
        vec)
      "remote-path"
    (let* ((remote-path (copy-tree tramp-remote-path))
           (elt1 (memq 'tramp-default-remote-path remote-path))
           (elt2 (memq 'tramp-own-remote-path remote-path))
           (default-remote-path
             (when elt1
               (or
                (tramp-send-command-and-read
                 vec "echo \\\"`getconf PATH 2>/dev/null`\\\"" 'noerror)
                ;; Default if "getconf" is not available.
                (progn
                  (tramp-message
                   vec 3
                   "`getconf PATH' not successful, using default value \"%s\"."
                   "/bin:/usr/bin")
                  "/bin:/usr/bin"))))
           (own-remote-path
            ;; The login shell could return more than just the $PATH
            ;; string.  So we use `tramp-end-of-heredoc' as marker.
            (when elt2
              (or
               (tramp-send-command-and-read
                vec
                (format
                 "%s %s %s 'echo %s \\\"$PATH\\\"'"
                 (tramp-get-method-parameter vec 'tramp-remote-shell)
                 (mapconcat
                  'identity
                  (tramp-get-method-parameter vec 'tramp-remote-shell-login)
                  " ")
                 (mapconcat
                  'identity
                  (tramp-get-method-parameter vec 'tramp-remote-shell-args)
                  " ")
                 (tramp-shell-quote-argument tramp-end-of-heredoc))
                'noerror (regexp-quote tramp-end-of-heredoc))
               (progn
                 (tramp-message
                  vec 2 "Could not retrieve `tramp-own-remote-path'")
                 nil)))))

      ;; Replace place holder `tramp-default-remote-path'.
      (when elt1
        (setcdr elt1
                (append
                 (split-string (or default-remote-path "") ":" 'omit)
                 (cdr elt1)))
        (setq remote-path (delq 'tramp-default-remote-path remote-path)))

      ;; Replace place holder `tramp-own-remote-path'.
      (when elt2
        (setcdr elt2
                (append
                 (split-string (or own-remote-path "") ":" 'omit)
                 (cdr elt2)))
        (setq remote-path (delq 'tramp-own-remote-path remote-path)))

      ;; Remove double entries.
      (setq elt1 remote-path)
      (while (consp elt1)
        (while (and (car elt1) (setq elt2 (member (car elt1) (cdr elt1))))
          (setcar elt2 nil))
        (setq elt1 (cdr elt1)))

      ;; Remove non-existing directories.
      (delq
       nil
       (mapcar
        (lambda (x)
          (and
           (stringp x)
           (file-directory-p
            (tramp-make-tramp-file-name
             (tramp-file-name-method vec)
             (tramp-file-name-user vec)
             (tramp-file-name-host vec)
             x))
           x))
        remote-path)))))

(defun tramp-get-remote-locale (vec)
  (with-tramp-connection-property vec "locale"
    (tramp-send-command vec "locale -a")
    (let ((candidates '("en_US.utf8" "C.utf8" "en_US.UTF-8"))
          locale)
      (with-current-buffer (tramp-get-connection-buffer vec)
        (while candidates
          (goto-char (point-min))
          (if (string-match (format "^%s\r?$" (regexp-quote (car candidates)))
                            (buffer-string))
              (setq locale (car candidates)
                    candidates nil)
            (setq candidates (cdr candidates)))))
      ;; Return value.
      (format "LC_ALL=%s" (or locale "C")))))

(defun tramp-get-ls-command (vec)
  (with-tramp-connection-property vec "ls"
    (tramp-message vec 5 "Finding a suitable `ls' command")
    (or
     (catch 'ls-found
       (dolist (cmd '("ls" "gnuls" "gls"))
         (let ((dl (tramp-get-remote-path vec))
               result)
           (while (and dl (setq result (tramp-find-executable vec cmd dl t t)))
             ;; Check parameters.  On busybox, "ls" output coloring is
             ;; enabled by default sometimes.  So we try to disable it
             ;; when possible.  $LS_COLORING is not supported there.
             ;; Some "ls" versions are sensible wrt the order of
             ;; arguments, they fail when "-al" is after the
             ;; "--color=never" argument (for example on FreeBSD).
             (when (tramp-send-command-and-check
                    vec (format "%s -lnd /" result))
               (when (tramp-send-command-and-check
                      vec (format
                           "%s --color=never -al /dev/null" result))
                 (setq result (concat result " --color=never")))
               (throw 'ls-found result))
             (setq dl (cdr dl))))))
     (tramp-error vec 'file-error "Couldn't find a proper `ls' command"))))

(defun tramp-get-ls-command-with-dired (vec)
  (save-match-data
    (with-tramp-connection-property vec "ls-dired"
      (tramp-message vec 5 "Checking, whether `ls --dired' works")
      ;; Some "ls" versions are sensible wrt the order of arguments,
      ;; they fail when "-al" is after the "--dired" argument (for
      ;; example on FreeBSD).
      (tramp-send-command-and-check
       vec (format "%s --dired -al /dev/null" (tramp-get-ls-command vec))))))

(defun tramp-get-ls-command-with-quoting-style (vec)
  (save-match-data
    (with-tramp-connection-property vec "ls-quoting-style"
      (tramp-message vec 5 "Checking, whether `ls --quoting-style=shell' works")
      (tramp-send-command-and-check
       vec (format "%s --quoting-style=shell -al /dev/null"
                   (tramp-get-ls-command vec))))))

(defun tramp-get-ls-command-with-w-option (vec)
  (save-match-data
    (with-tramp-connection-property vec "ls-w-option"
      (tramp-message vec 5 "Checking, whether `ls -w' works")
      ;; Option "-w" is available on BSD systems.  No argument is
      ;; given, because this could return wrong results in case "ls"
      ;; supports the "-w NUM" argument, as for busyboxes.
      (tramp-send-command-and-check
       vec (format "%s -alw" (tramp-get-ls-command vec))))))

(defun tramp-get-test-command (vec)
  (with-tramp-connection-property vec "test"
    (tramp-message vec 5 "Finding a suitable `test' command")
    (if (tramp-send-command-and-check vec "test 0")
        "test"
      (tramp-find-executable vec "test" (tramp-get-remote-path vec)))))

(defun tramp-get-test-nt-command (vec)
  ;; Does `test A -nt B' work?  Use abominable `find' construct if it
  ;; doesn't.  BSD/OS 4.0 wants the parentheses around the command,
  ;; for otherwise the shell crashes.
  (with-tramp-connection-property vec "test-nt"
    (or
     (progn
       (tramp-send-command
        vec (format "( %s / -nt / )" (tramp-get-test-command vec)))
       (with-current-buffer (tramp-get-buffer vec)
         (goto-char (point-min))
         (when (looking-at (regexp-quote tramp-end-of-output))
           (format "%s %%s -nt %%s" (tramp-get-test-command vec)))))
     (progn
       (tramp-send-command
        vec
        (format
         "tramp_test_nt () {\n%s -n \"`find $1 -prune -newer $2 -print`\"\n}"
         (tramp-get-test-command vec)))
       "tramp_test_nt %s %s"))))

(defun tramp-get-file-exists-command (vec)
  (with-tramp-connection-property vec "file-exists"
    (tramp-message vec 5 "Finding command to check if file exists")
    (tramp-find-file-exists-command vec)))

(defun tramp-get-remote-ln (vec)
  (with-tramp-connection-property vec "ln"
    (tramp-message vec 5 "Finding a suitable `ln' command")
    (tramp-find-executable vec "ln" (tramp-get-remote-path vec))))

(defun tramp-get-remote-perl (vec)
  (with-tramp-connection-property vec "perl"
    (tramp-message vec 5 "Finding a suitable `perl' command")
    (let ((result
           (or (tramp-find-executable vec "perl5" (tramp-get-remote-path vec))
               (tramp-find-executable
                vec "perl" (tramp-get-remote-path vec)))))
      ;; We must check also for some Perl modules.
      (when result
        (with-tramp-connection-property vec "perl-file-spec"
           (tramp-send-command-and-check
            vec (format "%s -e 'use File::Spec;'" result)))
        (with-tramp-connection-property vec "perl-cwd-realpath"
           (tramp-send-command-and-check
            vec (format "%s -e 'use Cwd \"realpath\";'" result))))
      result)))

(defun tramp-get-remote-stat (vec)
  (with-tramp-connection-property vec "stat"
    (tramp-message vec 5 "Finding a suitable `stat' command")
    (let ((result (tramp-find-executable
                   vec "stat" (tramp-get-remote-path vec)))
          tmp)
      ;; Check whether stat(1) returns usable syntax.  "%s" does not
      ;; work on older AIX systems.  Recent GNU stat versions (8.24?)
      ;; use shell quoted format for "%N", we check the boundaries "`"
      ;; and "'", therefore.  See Bug#23422 in coreutils.
      (when result
        (setq tmp
              (tramp-send-command-and-read
               vec (format "%s -c '(\"%%N\" %%s)' /" result) 'noerror))
        (unless (and (listp tmp) (stringp (car tmp))
                     (string-match "^`/'$" (car tmp))
                     (integerp (cadr tmp)))
          (setq result nil)))
      result)))

(defun tramp-get-remote-readlink (vec)
  (with-tramp-connection-property vec "readlink"
    (tramp-message vec 5 "Finding a suitable `readlink' command")
    (let ((result (tramp-find-executable
                   vec "readlink" (tramp-get-remote-path vec))))
      (when (and result
                 (tramp-send-command-and-check
                  vec (format "%s --canonicalize-missing /" result)))
        result))))

(defun tramp-get-remote-trash (vec)
  (with-tramp-connection-property vec "trash"
    (tramp-message vec 5 "Finding a suitable `trash' command")
    (tramp-find-executable vec "trash" (tramp-get-remote-path vec))))

(defun tramp-get-remote-touch (vec)
  (with-tramp-connection-property vec "touch"
    (tramp-message vec 5 "Finding a suitable `touch' command")
    (let ((result (tramp-find-executable
                   vec "touch" (tramp-get-remote-path vec)))
          (tmpfile
           (make-temp-name
            (expand-file-name
             tramp-temp-name-prefix (tramp-get-remote-tmpdir vec)))))
      ;; Busyboxes do support the "-t" option only when they have been
      ;; built with the DESKTOP config option.  Let's check it.
      (when result
        (tramp-set-connection-property
         vec "touch-t"
         (tramp-send-command-and-check
          vec
          (format
           "%s -t %s %s"
           result
           (format-time-string "%Y%m%d%H%M.%S")
           (file-remote-p tmpfile 'localname))))
        (delete-file tmpfile))
      result)))

(defun tramp-get-remote-gvfs-monitor-dir (vec)
  (with-tramp-connection-property vec "gvfs-monitor-dir"
    (tramp-message vec 5 "Finding a suitable `gvfs-monitor-dir' command")
    (tramp-find-executable
     vec "gvfs-monitor-dir" (tramp-get-remote-path vec) t t)))

(defun tramp-get-remote-inotifywait (vec)
  (with-tramp-connection-property vec "inotifywait"
    (tramp-message vec 5 "Finding a suitable `inotifywait' command")
    (tramp-find-executable vec "inotifywait" (tramp-get-remote-path vec) t t)))

(defun tramp-get-remote-id (vec)
  (with-tramp-connection-property vec "id"
    (tramp-message vec 5 "Finding POSIX `id' command")
    (catch 'id-found
      (dolist (cmd '("id" "gid"))
        (let ((dl (tramp-get-remote-path vec))
              result)
          (while (and dl (setq result (tramp-find-executable vec cmd dl t t)))
            ;; Check POSIX parameter.
            (when (tramp-send-command-and-check vec (format "%s -u" result))
              (throw 'id-found result))
            (setq dl (cdr dl))))))))

(defun tramp-get-remote-uid-with-id (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -u%s %s"
           (tramp-get-remote-id vec)
           (if (equal id-format 'integer) "" "n")
           (if (equal id-format 'integer)
               "" "| sed -e s/^/\\\"/ -e s/\\$/\\\"/"))))

(defun tramp-get-remote-uid-with-perl (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -le '%s'"
           (tramp-get-remote-perl vec)
           (if (equal id-format 'integer)
               "print $>"
             "print \"\\\"\", scalar getpwuid($>), \"\\\"\""))))

(defun tramp-get-remote-python (vec)
  (with-tramp-connection-property vec "python"
    (tramp-message vec 5 "Finding a suitable `python' command")
    (or (tramp-find-executable vec "python" (tramp-get-remote-path vec))
        (tramp-find-executable vec "python2" (tramp-get-remote-path vec))
        (tramp-find-executable vec "python3" (tramp-get-remote-path vec)))))

(defun tramp-get-remote-uid-with-python (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -c \"%s\""
           (tramp-get-remote-python vec)
           (if (equal id-format 'integer)
               "import os; print (os.getuid())"
             "import os, pwd; print ('\\\"' + pwd.getpwuid(os.getuid())[0] + '\\\"')"))))

(defun tramp-get-remote-uid (vec id-format)
  (with-tramp-connection-property vec (format "uid-%s" id-format)
    (let ((res
           (ignore-errors
             (cond
              ((tramp-get-remote-id vec)
               (tramp-get-remote-uid-with-id vec id-format))
              ((tramp-get-remote-perl vec)
               (tramp-get-remote-uid-with-perl vec id-format))
              ((tramp-get-remote-python vec)
               (tramp-get-remote-uid-with-python vec id-format))))))
      ;; Ensure there is a valid result.
      (cond
       ((and (equal id-format 'integer) (not (integerp res)))
        tramp-unknown-id-integer)
       ((and (equal id-format 'string) (not (stringp res)))
        tramp-unknown-id-string)
       (t res)))))

(defun tramp-get-remote-gid-with-id (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -g%s %s"
           (tramp-get-remote-id vec)
           (if (equal id-format 'integer) "" "n")
           (if (equal id-format 'integer)
               "" "| sed -e s/^/\\\"/ -e s/\\$/\\\"/"))))

(defun tramp-get-remote-gid-with-perl (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -le '%s'"
           (tramp-get-remote-perl vec)
           (if (equal id-format 'integer)
               "print ($)=~/(\\d+)/)"
             "print \"\\\"\", scalar getgrgid($)), \"\\\"\""))))

(defun tramp-get-remote-gid-with-python (vec id-format)
  (tramp-send-command-and-read
   vec
   (format "%s -c \"%s\""
           (tramp-get-remote-python vec)
           (if (equal id-format 'integer)
               "import os; print (os.getgid())"
             "import os, grp; print ('\\\"' + grp.getgrgid(os.getgid())[0] + '\\\"')"))))

(defun tramp-get-remote-gid (vec id-format)
  (with-tramp-connection-property vec (format "gid-%s" id-format)
    (let ((res
           (ignore-errors
             (cond
              ((tramp-get-remote-id vec)
               (tramp-get-remote-gid-with-id vec id-format))
              ((tramp-get-remote-perl vec)
               (tramp-get-remote-gid-with-perl vec id-format))
              ((tramp-get-remote-python vec)
               (tramp-get-remote-gid-with-python vec id-format))))))
      ;; Ensure there is a valid result.
      (cond
       ((and (equal id-format 'integer) (not (integerp res)))
        tramp-unknown-id-integer)
       ((and (equal id-format 'string) (not (stringp res)))
        tramp-unknown-id-string)
       (t res)))))

;; Some predefined connection properties.
(defun tramp-get-inline-compress (vec prop size)
  "Return the compress command related to PROP.
PROP is either `inline-compress' or `inline-decompress'. SIZE is
the length of the file to be compressed.

If no corresponding command is found, nil is returned."
  (when (and (integerp tramp-inline-compress-start-size)
             (> size tramp-inline-compress-start-size))
    (with-tramp-connection-property (tramp-get-connection-process vec) prop
      (tramp-find-inline-compress vec)
      (tramp-get-connection-property
       (tramp-get-connection-process vec) prop nil))))

(defun tramp-get-inline-coding (vec prop size)
  "Return the coding command related to PROP.
PROP is either `remote-encoding', `remote-decoding',
`local-encoding' or `local-decoding'.

SIZE is the length of the file to be coded.  Depending on SIZE,
compression might be applied.

If no corresponding command is found, nil is returned.
Otherwise, either a string is returned which contains a `%s' mark
to be used for the respective input or output file; or a Lisp
function cell is returned to be applied on a buffer."
  ;; We must catch the errors, because we want to return nil, when
  ;; no inline coding is found.
  (ignore-errors
    (let ((coding
           (with-tramp-connection-property
               (tramp-get-connection-process vec) prop
             (tramp-find-inline-encoding vec)
             (tramp-get-connection-property
              (tramp-get-connection-process vec) prop nil)))
          (prop1 (if (string-match "encoding" prop)
                     "inline-compress" "inline-decompress"))
          compress)
      ;; The connection property might have been cached.  So we must
      ;; send the script to the remote side - maybe.
      (when (and coding (symbolp coding) (string-match "remote" prop))
        (let ((name (symbol-name coding)))
          (while (string-match (regexp-quote "-") name)
            (setq name (replace-match "_" nil t name)))
          (tramp-maybe-send-script vec (symbol-value coding) name)
          (setq coding name)))
      (when coding
        ;; Check for the `compress' command.
        (setq compress (tramp-get-inline-compress vec prop1 size))
        ;; Return the value.
        (cond
         ((and compress (symbolp coding))
          (if (string-match "decompress" prop1)
              `(lambda (beg end)
                 (,coding beg end)
                 (let ((coding-system-for-write 'binary)
                       (coding-system-for-read 'binary)
                       (default-directory
                         (tramp-compat-temporary-file-directory)))
                   (apply
                    'tramp-call-process-region ,vec (point-min) (point-max)
                    (car (split-string ,compress)) t t nil
                    (cdr (split-string ,compress)))))
            `(lambda (beg end)
               (let ((coding-system-for-write 'binary)
                     (coding-system-for-read 'binary)
                     (default-directory
                       (tramp-compat-temporary-file-directory)))
                 (apply
                  'tramp-call-process-region ,vec beg end
                  (car (split-string ,compress)) t t nil
                  (cdr (split-string ,compress))))
               (,coding (point-min) (point-max)))))
         ((symbolp coding)
          coding)
         ((and compress (string-match "decoding" prop))
          (format
           ;; Windows shells need the program file name after
           ;; the pipe symbol be quoted if they use forward
           ;; slashes as directory separators.
           (cond
            ((and (string-match "local" prop)
                  (memq system-type '(windows-nt)))
               "(%s | \"%s\")")
            ((string-match "local" prop) "(%s | %s)")
            (t "(%s | %s >%%s)"))
           coding compress))
         (compress
          (format
           ;; Windows shells need the program file name after
           ;; the pipe symbol be quoted if they use forward
           ;; slashes as directory separators.
           (if (and (string-match "local" prop)
                    (memq system-type '(windows-nt)))
               "(%s <%%s | \"%s\")"
             "(%s <%%s | %s)")
           compress coding))
         ((string-match "decoding" prop)
          (cond
           ((string-match "local" prop) (format "%s" coding))
           (t (format "%s >%%s" coding))))
         (t
          (format "%s <%%s" coding)))))))

(add-hook 'tramp-unload-hook
          (lambda ()
            (unload-feature 'tramp-sh 'force)))

(provide 'tramp-sh)

;;; TODO:

;; * Don't use globbing for directories with many files, as this is
;;   likely to produce long command lines, and some shells choke on
;;   long command lines.
;; * Don't search for perl5 and perl.  Instead, only search for perl and
;;   then look if it's the right version (with `perl -v').
;; * When editing a remote CVS controlled file as a different user, VC
;;   gets confused about the file locking status.  Try to find out why
;;   the workaround doesn't work.
;; * Allow out-of-band methods as _last_ multi-hop.  Open a connection
;;   until the last but one hop via `start-file-process'.  Apply it
;;   also for ftp and smb.
;; * WIBNI if we had a command "trampclient"?  If I was editing in
;;   some shell with root privileges, it would be nice if I could
;;   just call
;;     trampclient filename.c
;;   as an editor, and the _current_ shell would connect to an Emacs
;;   server and would be used in an existing non-privileged Emacs
;;   session for doing the editing in question.
;;   That way, I need not tell Emacs my password again and be afraid
;;   that it makes it into core dumps or other ugly stuff (I had Emacs
;;   once display a just typed password in the context of a keyboard
;;   sequence prompt for a question immediately following in a shell
;;   script run within Emacs -- nasty).
;;   And if I have some ssh session running to a different computer,
;;   having the possibility of passing a local file there to a local
;;   Emacs session (in case I can arrange for a connection back) would
;;   be nice.
;;   Likely the corresponding Tramp server should not allow the
;;   equivalent of the emacsclient -eval option in order to make this
;;   reasonably unproblematic.  And maybe trampclient should have some
;;   way of passing credentials, like by using an SSL socket or
;;   something.  (David Kastrup)
;; * Reconnect directly to a compliant shell without first going
;;   through the user's default shell.  (Pete Forman)
;; * How can I interrupt the remote process with a signal
;;   (interrupt-process seems not to work)?  (Markus Triska)
;; * Avoid the local shell entirely for starting remote processes.  If
;;   so, I think even a signal, when delivered directly to the local
;;   SSH instance, would correctly be propagated to the remote process
;;   automatically; possibly SSH would have to be started with
;;   "-t".  (Markus Triska)
;; * It makes me wonder if tramp couldn't fall back to ssh when scp
;;   isn't on the remote host.  (Mark A. Hershberger)
;; * Use lsh instead of ssh.  (Alfred M. Szmidt)
;; * Optimize out-of-band copying when both methods are scp-like (not
;;   rsync).
;; * Keep a second connection open for out-of-band methods like scp or
;;   rsync.

;;; tramp-sh.el ends here