From: Matthew Leach Date: Sat, 16 Apr 2016 09:43:01 +0000 (+0300) Subject: Add external socket launching support X-Git-Url: https://code.delx.au/gnu-emacs/commitdiff_plain/e390b7b54651d3c5a4c36168e84e96e197631f41 Add external socket launching support * src/process.c (connect_network_socket): Allow a pre-allocated socket descriptor to be used if passed to Emacs, avoiding the call to 'socket' and 'bind'. (Fmake_network_process): Allow users to pass ':use-external-socket' in the parameter plist to use any sockets that have been passed to Emacs. (wait_reading_process_output): Call 'socket' and 'bind' every time. (syms_of_process): New symbol ':use-external-socket'. (set_external_socket_descriptor): New function. (external_sock_fd): New variable. * src/lisp.h: (set_external_socket_descriptor): New declaration. * src/emacs.c (main): Call 'sd_listen_fds' to read the number of sockets passed and call 'set_external_socket_descriptor' to set the external socket. * src/Makefile.in: Add libsystemd library and C flags to the Emacs compilation options. * configure.ac: Add new default-on option "systemd" and check for libsystemd at configure time. * lisp/server.el (server-start): Set ':use-external-socket' to 't' when calling 'make-network-process'. * etc/NEWS: Document new socket-passing functionality and the configure option to disable systemd interaction. * doc/emacs/misc.texi (Emacs Server): Document systemd socket passing functionality and provide systemd unit examples. * doc/lispref/processes.texi (Network Processes): Document new 'make-network-process' option ':use-external-socket'. --- diff --git a/configure.ac b/configure.ac index 8f311cf787..54e9ec5c31 100644 --- a/configure.ac +++ b/configure.ac @@ -330,6 +330,7 @@ OPTION_DEFAULT_ON([tiff],[don't compile with TIFF image support]) OPTION_DEFAULT_ON([gif],[don't compile with GIF image support]) OPTION_DEFAULT_ON([png],[don't compile with PNG image support]) OPTION_DEFAULT_ON([rsvg],[don't compile with SVG image support]) +OPTION_DEFAULT_ON([libsystemd],[don't compile with libsystemd support]) OPTION_DEFAULT_OFF([cairo],[compile with Cairo drawing (experimental)]) OPTION_DEFAULT_ON([xml2],[don't compile with XML parsing support]) OPTION_DEFAULT_ON([imagemagick],[don't compile with ImageMagick image support]) @@ -2732,6 +2733,18 @@ fi AC_SUBST(LIBGNUTLS_LIBS) AC_SUBST(LIBGNUTLS_CFLAGS) +HAVE_LIBSYSTEMD=no +if test "${with_libsystemd}" = "yes" ; then + EMACS_CHECK_MODULES([LIBSYSTEMD], [libsystemd >= 226], + [HAVE_LIBSYSTEMD=yes], [HAVE_LIBSYSTEMD=no]) + if test "${HAVE_LIBSYSTEMD}" = "yes"; then + AC_DEFINE(HAVE_LIBSYSTEMD, 1, [Define if using libsystemd.]) + fi +fi + +AC_SUBST(LIBSYSTEMD_LIBS) +AC_SUBST(LIBSYSTEMD_CFLAGS) + NOTIFY_OBJ= NOTIFY_SUMMARY=no diff --git a/doc/emacs/misc.texi b/doc/emacs/misc.texi index b5a21500fc..775cda9349 100644 --- a/doc/emacs/misc.texi +++ b/doc/emacs/misc.texi @@ -1580,6 +1580,44 @@ option. @xref{Initial Options}. When Emacs is started this way, it calls @code{server-start} after initialization, and returns control to the calling terminal instead of opening an initial frame; it then waits in the background, listening for edit requests. + +@cindex socket activation, systemd, Emacs +@item +An external process can invoke the Emacs server when a connection +event occurs upon a specified socket and pass the socket to the new +Emacs server process. An instance of this is @command{systemd}'s +socket functionaly: the @command{systemd} service creates a socket and +listens for connections on it; when @command{emacsclient} connects to +it for the first time, @command{systemd} can launch the Emacs server +and hand over the socket to it for servicing @command{emacsclient} +connections. A setup to use this functionality could be: + +@file{~/.config/systemd/user/emacs.service}: +@example +[Unit] +Description=Emacs + +[Service] +Type=forking +ExecStart=/path/to/emacs --daemon +ExecStop=/path/to/emacsclient --eval "(kill-emacs)" +Restart=always + +[Install] +WantedBy=default.target +@end example + +@file{~/.config/systemd/user/emacs.socket}: +@example +[Socket] +ListenStream=/path/to/.emacs.socket + +[Install] +WantedBy=sockets.target +@end example + +The @code{ListenStream} path will be the path that Emacs listens for +connections from @command{emacsclient}; this is a file of your choice. @end itemize @cindex @env{TEXEDIT} environment variable diff --git a/doc/lispref/processes.texi b/doc/lispref/processes.texi index b66f779bdd..e8a9ad05c2 100644 --- a/doc/lispref/processes.texi +++ b/doc/lispref/processes.texi @@ -2367,6 +2367,12 @@ automatically for the given @var{host} and @var{service}. ignored. @code{ipv4} and @code{ipv6} specify to use IPv4 and IPv6, respectively. +@item :use-external-socket @var{use-external-socket} +If @var{use-external-socket} is non-@code{nil} use any sockets passed +to Emacs on invocation instead of allocating one. This is used by the +Emacs server code to allow on-demand socket activation. If Emacs +wasn't passed a socket, this option is silently ignored. + @item :local @var{local-address} For a server process, @var{local-address} is the address to listen on. It overrides @var{family}, @var{host} and @var{service}, so you diff --git a/etc/NEWS b/etc/NEWS index 5ebff6267f..f4a45261f8 100644 --- a/etc/NEWS +++ b/etc/NEWS @@ -32,6 +32,13 @@ the default in developer builds. As before, use '--enable-gcc-warnings' to stop the build if GCC issues warnings. +++ +** Emacs server now has socket-launching support. This allows socket +based activation, where an external process can invoke the Emacs +server process upon a socket connection event and hand over the socket +to Emacs. Emacs will use this socket for servicing emacsclient +commands. systemd can make use of this new functionally but can be +disabled with the configure option '--disable-libsystemd'. + ** New configure option '--disable-build-details' attempts to build an Emacs that is more likely to be reproducible; that is, if you build and install Emacs twice, the second Emacs is a copy of the first. diff --git a/lisp/server.el b/lisp/server.el index 524382073f..2a9729e9d1 100644 --- a/lisp/server.el +++ b/lisp/server.el @@ -655,6 +655,7 @@ server or call `\\[server-force-delete]' to forcibly disconnect it.")) :noquery t :sentinel #'server-sentinel :filter #'server-process-filter + :use-external-socket t ;; We must receive file names without being decoded. ;; Those are decoded by server-process-filter according ;; to file-name-coding-system. Also don't get diff --git a/src/Makefile.in b/src/Makefile.in index c290a6082d..fc9360a5bd 100644 --- a/src/Makefile.in +++ b/src/Makefile.in @@ -307,6 +307,9 @@ LIBSELINUX_LIBS = @LIBSELINUX_LIBS@ LIBGNUTLS_LIBS = @LIBGNUTLS_LIBS@ LIBGNUTLS_CFLAGS = @LIBGNUTLS_CFLAGS@ +LIBSYSTEMD_LIBS = @LIBSYSTEMD_LIBS@ +LIBSYSTEMD_CFLAGS = @LIBSYSTEMD_CFLAGS@ + INTERVALS_H = dispextern.h intervals.h composite.h GETLOADAVG_LIBS = @GETLOADAVG_LIBS@ @@ -372,6 +375,7 @@ ALL_CFLAGS=-Demacs $(MYCPPFLAGS) -I. -I$(srcdir) \ $(WEBKIT_CFLAGS) \ $(SETTINGS_CFLAGS) $(FREETYPE_CFLAGS) $(FONTCONFIG_CFLAGS) \ $(LIBOTF_CFLAGS) $(M17N_FLT_CFLAGS) $(DEPFLAGS) \ + $(LIBSYSTEMD_CFLAGS) \ $(LIBGNUTLS_CFLAGS) $(NOTIFY_CFLAGS) $(CAIRO_CFLAGS) \ $(WARN_CFLAGS) $(WERROR_CFLAGS) $(CFLAGS) ALL_OBJC_CFLAGS=$(ALL_CFLAGS) $(GNU_OBJC_CFLAGS) @@ -489,7 +493,7 @@ LIBES = $(LIBS) $(W32_LIBS) $(LIBS_GNUSTEP) $(LIBX_BASE) $(LIBIMAGE) \ $(LIBS_TERMCAP) $(GETLOADAVG_LIBS) $(SETTINGS_LIBS) $(LIBSELINUX_LIBS) \ $(FREETYPE_LIBS) $(FONTCONFIG_LIBS) $(LIBOTF_LIBS) $(M17N_FLT_LIBS) \ $(LIBGNUTLS_LIBS) $(LIB_PTHREAD) $(GETADDRINFO_A_LIBS) \ - $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) + $(NOTIFY_LIBS) $(LIB_MATH) $(LIBZ) $(LIBMODULES) $(LIBSYSTEMD_LIBS) $(leimdir)/leim-list.el: bootstrap-emacs$(EXEEXT) $(MAKE) -C ../leim leim-list.el EMACS="$(bootstrap_exe)" diff --git a/src/emacs.c b/src/emacs.c index c21c9e3971..a51df0903b 100644 --- a/src/emacs.c +++ b/src/emacs.c @@ -56,6 +56,11 @@ along with GNU Emacs. If not, see . */ #include #endif +#ifdef HAVE_LIBSYSTEMD +#include +#include +#endif /* HAVE_LIBSYSTEMD */ + #ifdef HAVE_WINDOW_SYSTEM #include TERM_HEADER #endif /* HAVE_WINDOW_SYSTEM */ @@ -676,6 +681,9 @@ main (int argc, char **argv) char dname_arg2[80]; #endif char *ch_to_dir = 0; +#ifdef HAVE_LIBSYSTEMD + int systemd_socket; +#endif /* If we use --chdir, this records the original directory. */ char *original_pwd = 0; @@ -999,6 +1007,20 @@ main (int argc, char **argv) exit (1); } +#ifdef HAVE_LIBSYSTEMD + /* Read the number of sockets passed through by systemd. */ + systemd_socket = sd_listen_fds(1); + + if (systemd_socket > 1) + fprintf (stderr, "\nWarning: systemd has passed more than one socket to the Emacs process.\n\ +Try adding 'Accept=false' in the Emacs socket unit file.\n"); + + else if (systemd_socket == 1 && + sd_is_socket (SD_LISTEN_FDS_START, + AF_UNSPEC, SOCK_STREAM, 1) >= 0) + set_external_socket_descriptor (SD_LISTEN_FDS_START); +#endif /* HAVE_LIBSYSTEMD */ + #ifndef DAEMON_MUST_EXEC #ifdef USE_GTK fprintf (stderr, "\nWarning: due to a long standing Gtk+ bug\nhttp://bugzilla.gnome.org/show_bug.cgi?id=85715\n\ diff --git a/src/lisp.h b/src/lisp.h index d111a78f3e..c6f8bb89a3 100644 --- a/src/lisp.h +++ b/src/lisp.h @@ -4184,6 +4184,7 @@ extern void delete_gpm_wait_descriptor (int); extern void init_process_emacs (void); extern void syms_of_process (void); extern void setup_process_coding_systems (Lisp_Object); +extern void set_external_socket_descriptor (int); /* Defined in callproc.c. */ #ifndef DOS_NT diff --git a/src/process.c b/src/process.c index a006ca61ac..2dfad66907 100644 --- a/src/process.c +++ b/src/process.c @@ -267,6 +267,9 @@ static int max_process_desc; /* The largest descriptor currently in use for input; -1 if none. */ static int max_input_desc; +/* The descriptor of any sockets passed to Emacs; -1 if none. */ +static int external_sock_fd = -1; + /* Indexed by descriptor, gives the process (if any) for that descriptor. */ static Lisp_Object chan_process[FD_SETSIZE]; static void wait_for_socket_fds (Lisp_Object, char const *); @@ -3075,7 +3078,8 @@ finish_after_tls_connection (Lisp_Object proc) #endif static void -connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) +connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses, + Lisp_Object use_external_socket_p) { ptrdiff_t count = SPECPDL_INDEX (); ptrdiff_t count1; @@ -3089,6 +3093,16 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) struct Lisp_Process *p = XPROCESS (proc); Lisp_Object contact = p->childp; int optbits = 0; + int socket_to_use = -1; + + if (!NILP (use_external_socket_p)) + { + socket_to_use = external_sock_fd; + + /* Ensure we don't consume the external socket twice. */ + external_sock_fd = -1; + } + /* Do this in case we never enter the while-loop below. */ count1 = SPECPDL_INDEX (); @@ -3109,7 +3123,11 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) sa = xmalloc (addrlen); conv_lisp_to_sockaddr (family, ip_address, sa, addrlen); - s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol); + if (socket_to_use != -1) + s = socket_to_use; + else + s = socket (family, p->socktype | SOCK_CLOEXEC, p->ai_protocol); + if (s < 0) { xerrno = errno; @@ -3168,8 +3186,11 @@ connect_network_socket (Lisp_Object proc, Lisp_Object ip_addresses) report_file_error ("Cannot set reuse option on server socket", Qnil); } - if (bind (s, sa, addrlen)) - report_file_error ("Cannot bind server socket", Qnil); + /* If we are passed a socket descriptor, it should be + already bound. */ + if (socket_to_use == -1) + if (bind (s, sa, addrlen)) + report_file_error ("Cannot bind server socket", Qnil); #ifdef HAVE_GETSOCKNAME if (p->port == 0) @@ -3534,6 +3555,11 @@ The following network options can be specified for this connection: (this is allowed by default for a server process). :bindtodevice NAME -- bind to interface NAME. Using this may require special privileges on some systems. +:use-external-socket BOOL -- Use any pre-allocated sockets that have + been passed to Emacs. If Emacs wasn't + passed a socket, this option is silently + ignored. + Consult the relevant system programmer's manual pages for more information on using these options. @@ -3578,7 +3604,7 @@ usage: (make-network-process &rest ARGS) */) EMACS_INT port = 0; Lisp_Object tem; Lisp_Object name, buffer, host, service, address; - Lisp_Object filter, sentinel; + Lisp_Object filter, sentinel, use_external_socket_p; Lisp_Object ip_addresses = Qnil; int socktype; int family = -1; @@ -3618,6 +3644,7 @@ usage: (make-network-process &rest ARGS) */) buffer = Fplist_get (contact, QCbuffer); filter = Fplist_get (contact, QCfilter); sentinel = Fplist_get (contact, QCsentinel); + use_external_socket_p = Fplist_get (contact, QCuse_external_socket); CHECK_STRING (name); @@ -3914,7 +3941,7 @@ usage: (make-network-process &rest ARGS) */) } #endif - connect_network_socket (proc, ip_addresses); + connect_network_socket (proc, ip_addresses, use_external_socket_p); return proc; } @@ -4848,7 +4875,7 @@ wait_reading_process_output (intmax_t time_limit, int nsecs, int read_kbd, { Lisp_Object ip_addresses = check_for_dns (aproc); if (!NILP (ip_addresses) && !EQ (ip_addresses, Qt)) - connect_network_socket (aproc, ip_addresses); + connect_network_socket (aproc, ip_addresses, Qnil); else retry_for_async = true; } @@ -7709,6 +7736,16 @@ catch_child_signal (void) } #endif /* subprocesses */ +/* Set the external socket descriptor for Emacs to use when + `make-network-process' is called with a non-nil + `:use-external-socket' option. The fd should have been checked to + ensure it is a valid socket and is already bound. */ +void +set_external_socket_descriptor(int fd) +{ + external_sock_fd = fd; +} + /* This is not called "init_process" because that is the name of a Mach system call, so it would cause problems on Darwin systems. */ @@ -7837,6 +7874,7 @@ syms_of_process (void) DEFSYM (QCserver, ":server"); DEFSYM (QCnowait, ":nowait"); DEFSYM (QCsentinel, ":sentinel"); + DEFSYM (QCuse_external_socket, ":use-external-socket"); DEFSYM (QCtls_parameters, ":tls-parameters"); DEFSYM (Qnsm_verify_connection, "nsm-verify-connection"); DEFSYM (QClog, ":log");