/* Filesystem notifications support with kqueue API.
- Copyright (C) 2015 Free Software Foundation, Inc.
+
+Copyright (C) 2015-2016 Free Software Foundation, Inc.
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.
+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
#include "keyboard.h"
#include "process.h"
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif /* HAVE_SYS_RESOURCE_H */
+
\f
/* File handle for kqueue. */
static int kqueuefd = -1;
-/* This is a list, elements are (DESCRIPTOR FILE FLAGS CALLBACK [DIRLIST]) */
+/* This is a list, elements are (DESCRIPTOR FILE FLAGS CALLBACK [DIRLIST]). */
static Lisp_Object watch_list;
+/* Generate a list from the directory_files_internal output.
+ Items are (INODE FILE-NAME LAST-MOD LAST-STATUS-MOD SIZE). */
+Lisp_Object
+kqueue_directory_listing (Lisp_Object directory_files)
+{
+ Lisp_Object dl, result = Qnil;
+
+ for (dl = directory_files; ! NILP (dl); dl = XCDR (dl)) {
+ /* We ignore "." and "..". */
+ if ((strcmp (".", SSDATA (XCAR (XCAR (dl)))) == 0) ||
+ (strcmp ("..", SSDATA (XCAR (XCAR (dl)))) == 0))
+ continue;
+
+ result = Fcons
+ (list5 (/* inode. */
+ Fnth (make_number (11), XCAR (dl)),
+ /* filename. */
+ XCAR (XCAR (dl)),
+ /* last modification time. */
+ Fnth (make_number (6), XCAR (dl)),
+ /* last status change time. */
+ Fnth (make_number (7), XCAR (dl)),
+ /* size. */
+ Fnth (make_number (8), XCAR (dl))),
+ result);
+ }
+ return result;
+}
+
/* Generate a file notification event. */
static void
-kqueue_generate_event
-(Lisp_Object ident, Lisp_Object actions, Lisp_Object file, Lisp_Object callback)
+kqueue_generate_event (Lisp_Object watch_object, Lisp_Object actions,
+ Lisp_Object file, Lisp_Object file1)
{
+ Lisp_Object flags, action, entry;
struct input_event event;
- EVENT_INIT (event);
- event.kind = FILE_NOTIFY_EVENT;
- event.frame_or_window = Qnil;
- event.arg = list2 (Fcons (ident, Fcons (actions, Fcons (file, Qnil))),
- callback);
+
+ /* Check, whether all actions shall be monitored. */
+ flags = Fnth (make_number (2), watch_object);
+ action = actions;
+ do {
+ if (NILP (action))
+ break;
+ entry = XCAR (action);
+ if (NILP (Fmember (entry, flags))) {
+ action = XCDR (action);
+ actions = Fdelq (entry, actions);
+ } else
+ action = XCDR (action);
+ } while (1);
/* Store it into the input event queue. */
- kbd_buffer_store_event (&event);
+ if (! NILP (actions)) {
+ EVENT_INIT (event);
+ event.kind = FILE_NOTIFY_EVENT;
+ event.frame_or_window = Qnil;
+ event.arg = list2 (Fcons (XCAR (watch_object),
+ Fcons (actions,
+ NILP (file1)
+ ? Fcons (file, Qnil)
+ : list2 (file, file1))),
+ Fnth (make_number (3), watch_object));
+ kbd_buffer_store_event (&event);
+ }
}
/* This compares two directory listings in case of a `write' event for
- a directory. The old directory listing is stored in watch_object,
- it will be replaced by a new directory listing at the end. */
+ a directory. Generate resulting file notification events. The old
+ directory listing is retrieved from watch_object, it will be
+ replaced by the new directory listing at the end of this
+ function. */
static void
kqueue_compare_dir_list (Lisp_Object watch_object)
{
- Lisp_Object dir, callback, old_dl, new_dl, dl, actions;
+ Lisp_Object dir, pending_dl, deleted_dl;
+ Lisp_Object old_directory_files, old_dl, new_directory_files, new_dl, dl;
dir = XCAR (XCDR (watch_object));
- callback = XCAR (XCDR (XCDR (XCDR (watch_object))));
- old_dl = XCAR (XCDR (XCDR (XCDR (XCDR (watch_object)))));
- new_dl = directory_files_internal (dir, Qnil, Qnil, Qnil, 1, Qnil);
+ pending_dl = Qnil;
+ deleted_dl = Qnil;
+
+ old_directory_files = Fnth (make_number (4), watch_object);
+ old_dl = kqueue_directory_listing (old_directory_files);
- for (dl = old_dl; ! NILP (dl); dl = XCDR (dl)) {
- Lisp_Object old_entry, new_entry;
+ /* When the directory is not accessible anymore, it has been deleted. */
+ if (NILP (Ffile_directory_p (dir))) {
+ kqueue_generate_event (watch_object, Fcons (Qdelete, Qnil), dir, Qnil);
+ return;
+ }
+ new_directory_files =
+ directory_files_internal (dir, Qnil, Qnil, Qnil, 1, Qnil);
+ new_dl = kqueue_directory_listing (new_directory_files);
+
+ /* Parse through the old list. */
+ dl = old_dl;
+ while (1) {
+ Lisp_Object old_entry, new_entry, dl1;
+ if (NILP (dl))
+ break;
+
+ /* Search for an entry with the same inode. */
old_entry = XCAR (dl);
- new_entry = Fassoc (XCAR (old_entry), new_dl);
+ new_entry = assq_no_quit (XCAR (old_entry), new_dl);
+ if (! NILP (Fequal (old_entry, new_entry))) {
+ /* Both entries are identical. Nothing to do. */
+ new_dl = Fdelq (new_entry, new_dl);
+ goto the_end;
+ }
- /* We ignore "." and "..". */
- if ((strcmp (".", SSDATA (XCAR (old_entry))) == 0) ||
- (strcmp ("..", SSDATA (XCAR (old_entry))) == 0))
- continue;
+ /* Both entries have the same inode. */
+ if (! NILP (new_entry)) {
+ /* Both entries have the same file name. */
+ if (strcmp (SSDATA (XCAR (XCDR (old_entry))),
+ SSDATA (XCAR (XCDR (new_entry)))) == 0) {
+ /* Modification time has been changed, the file has been written. */
+ if (NILP (Fequal (Fnth (make_number (2), old_entry),
+ Fnth (make_number (2), new_entry))))
+ kqueue_generate_event
+ (watch_object, Fcons (Qwrite, Qnil), XCAR (XCDR (old_entry)), Qnil);
+ /* Status change time has been changed, the file attributes
+ have changed. */
+ if (NILP (Fequal (Fnth (make_number (3), old_entry),
+ Fnth (make_number (3), new_entry))))
+ kqueue_generate_event
+ (watch_object, Fcons (Qattrib, Qnil),
+ XCAR (XCDR (old_entry)), Qnil);
+
+ } else {
+ /* The file has been renamed. */
+ kqueue_generate_event
+ (watch_object, Fcons (Qrename, Qnil),
+ XCAR (XCDR (old_entry)), XCAR (XCDR (new_entry)));
+ deleted_dl = Fcons (new_entry, deleted_dl);
+ }
+ new_dl = Fdelq (new_entry, new_dl);
+ goto the_end;
+ }
- /* A file has disappeared. */
- if (NILP (new_entry))
+ /* Search, whether there is a file with the same name but another
+ inode. */
+ for (dl1 = new_dl; ! NILP (dl1); dl1 = XCDR (dl1)) {
+ new_entry = XCAR (dl1);
+ if (strcmp (SSDATA (XCAR (XCDR (old_entry))),
+ SSDATA (XCAR (XCDR (new_entry)))) == 0) {
+ pending_dl = Fcons (new_entry, pending_dl);
+ new_dl = Fdelq (new_entry, new_dl);
+ goto the_end;
+ }
+ }
+
+ /* Check, whether this a pending file. */
+ new_entry = assq_no_quit (XCAR (old_entry), pending_dl);
+
+ if (NILP (new_entry)) {
+ /* Check, whether this is an already deleted file (by rename). */
+ for (dl1 = deleted_dl; ! NILP (dl1); dl1 = XCDR (dl1)) {
+ new_entry = XCAR (dl1);
+ if (strcmp (SSDATA (XCAR (XCDR (old_entry))),
+ SSDATA (XCAR (XCDR (new_entry)))) == 0) {
+ deleted_dl = Fdelq (new_entry, deleted_dl);
+ goto the_end;
+ }
+ }
+ /* The file has been deleted. */
kqueue_generate_event
- (XCAR (watch_object), Fcons (Qdelete, Qnil),
- XCAR (old_entry), callback);
-
- else {
- /* A file has changed. We compare last modification time. */
- if (NILP
- (Fequal
- (XCAR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (old_entry))))))),
- XCAR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (new_entry))))))))))
- kqueue_generate_event
- (XCAR (watch_object), Fcons (Qwrite, Qnil),
- XCAR (old_entry), callback);
-
- /* A file attribute has changed. We compare last status change time. */
- if (NILP
- (Fequal
- (XCAR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (old_entry)))))))),
- XCAR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (XCDR (new_entry)))))))))))
- kqueue_generate_event
- (XCAR (watch_object), Fcons (Qattrib, Qnil),
- XCAR (old_entry), callback);
+ (watch_object, Fcons (Qdelete, Qnil), XCAR (XCDR (old_entry)), Qnil);
+
+ } else {
+ /* The file has been renamed. */
+ kqueue_generate_event
+ (watch_object, Fcons (Qrename, Qnil),
+ XCAR (XCDR (old_entry)), XCAR (XCDR (new_entry)));
+ pending_dl = Fdelq (new_entry, pending_dl);
}
+
+ the_end:
+ dl = XCDR (dl);
+ old_dl = Fdelq (old_entry, old_dl);
}
- for (dl = new_dl; ! NILP (dl); dl = XCDR (dl)) {
- Lisp_Object old_entry, new_entry;
- new_entry = XCAR (dl);
- old_entry = Fassoc (XCAR (new_entry), old_dl);
-
- /* We ignore "." and "..". */
- if ((strcmp (".", SSDATA (XCAR (new_entry))) == 0) ||
- (strcmp ("..", SSDATA (XCAR (new_entry))) == 0))
- continue;
+ /* Parse through the resulting new list. */
+ dl = new_dl;
+ while (1) {
+ Lisp_Object entry;
+ if (NILP (dl))
+ break;
/* A new file has appeared. */
- if (NILP (old_entry))
+ entry = XCAR (dl);
+ kqueue_generate_event
+ (watch_object, Fcons (Qcreate, Qnil), XCAR (XCDR (entry)), Qnil);
+
+ /* Check size of that file. */
+ Lisp_Object size = Fnth (make_number (4), entry);
+ if (FLOATP (size) || (XINT (size) > 0))
kqueue_generate_event
- (XCAR (watch_object), Fcons (Qcreate, Qnil),
- XCAR (new_entry), callback);
+ (watch_object, Fcons (Qwrite, Qnil), XCAR (XCDR (entry)), Qnil);
+
+ dl = XCDR (dl);
+ new_dl = Fdelq (entry, new_dl);
+ }
+
+ /* Parse through the resulting pending_dl list. */
+ dl = pending_dl;
+ while (1) {
+ Lisp_Object entry;
+ if (NILP (dl))
+ break;
+
+ /* A file is still pending. Assume it was a write. */
+ entry = XCAR (dl);
+ kqueue_generate_event
+ (watch_object, Fcons (Qwrite, Qnil), XCAR (XCDR (entry)), Qnil);
+
+ dl = XCDR (dl);
+ pending_dl = Fdelq (entry, pending_dl);
}
- /* Replace directory listing with the new one. */
- XSETCDR (XCDR (XCDR (XCDR (watch_object))), Fcons (new_dl, Qnil));
+ /* At this point, old_dl, new_dl and pending_dl shall be empty.
+ deleted_dl might not be empty when there was a rename to a
+ nonexistent file. Let's make a check for this (might be removed
+ once the code is stable). */
+ if (! NILP (old_dl))
+ report_file_error ("Old list not empty", old_dl);
+ if (! NILP (new_dl))
+ report_file_error ("New list not empty", new_dl);
+ if (! NILP (pending_dl))
+ report_file_error ("Pending events list not empty", pending_dl);
+ // if (! NILP (deleted_dl))
+ // report_file_error ("Deleted events list not empty", deleted_dl);
+
+ /* Replace old directory listing with the new one. */
+ XSETCDR (Fnthcdr (make_number (3), watch_object),
+ Fcons (new_directory_files, Qnil));
return;
}
/* This is the callback function for arriving input on kqueuefd. It
- shall create a Lisp event, and put it into Emacs input queue. */
+ shall create a Lisp event, and put it into the Emacs input queue. */
static void
kqueue_callback (int fd, void *data)
{
for (;;) {
struct kevent kev;
static const struct timespec nullts = { 0, 0 };
- Lisp_Object monitor_object, watch_object, file, callback, dirp, actions;
+ Lisp_Object descriptor, watch_object, file, actions;
/* Read one event. */
int ret = kevent (kqueuefd, NULL, 0, &kev, 1, &nullts);
return;
}
- /* Determine file name and callback function. */
- monitor_object = make_number (kev.ident);
- watch_object = assq_no_quit (monitor_object, watch_list);
-
- if (CONSP (watch_object)) {
+ /* Determine descriptor and file name. */
+ descriptor = make_number (kev.ident);
+ watch_object = assq_no_quit (descriptor, watch_list);
+ if (CONSP (watch_object))
file = XCAR (XCDR (watch_object));
- callback = XCAR (XCDR (XCDR (XCDR (watch_object))));
- dirp = XCDR (XCDR (XCDR (XCDR (watch_object))));
- }
else
continue;
if (kev.fflags & NOTE_DELETE)
actions = Fcons (Qdelete, actions);
if (kev.fflags & NOTE_WRITE) {
- if (NILP (dirp))
+ /* Check, whether this is a directory event. */
+ if (NILP (Fnth (make_number (4), watch_object)))
actions = Fcons (Qwrite, actions);
else
kqueue_compare_dir_list (watch_object);
actions = Fcons (Qattrib, actions);
if (kev.fflags & NOTE_LINK)
actions = Fcons (Qlink, actions);
+ /* It would be useful to know the target of the rename operation.
+ At this point, it is not possible. Happens only when the upper
+ directory is monitored. */
if (kev.fflags & NOTE_RENAME)
actions = Fcons (Qrename, actions);
- /* Construct an event. */
+ /* Create the event. */
if (! NILP (actions))
- kqueue_generate_event (monitor_object, actions, file, callback);
+ kqueue_generate_event (watch_object, actions, file, Qnil);
- /* Cancel monitor if file or directory is deleted. */
+ /* Cancel monitor if file or directory is deleted or renamed. */
if (kev.fflags & (NOTE_DELETE | NOTE_RENAME))
- Fkqueue_rm_watch (monitor_object);
+ Fkqueue_rm_watch (descriptor);
}
return;
}
ACTIONS is a list of events.
FILE is the name of the file whose event is being reported. FILE1
-will be reported only in case of the `rename' event. */)
+will be reported only in case of the `rename' event. This is possible
+only when the upper directory of the renamed file is watched. */)
(Lisp_Object file, Lisp_Object flags, Lisp_Object callback)
{
Lisp_Object watch_object, dir_list;
- int fd;
+ int maxfd, fd, oflags;
u_short fflags = 0;
- struct kevent ev;
+ struct kevent kev;
+#ifdef HAVE_GETRLIMIT
+ struct rlimit rlim;
+#endif /* HAVE_GETRLIMIT */
/* Check parameters. */
CHECK_STRING (file);
if (! FUNCTIONP (callback))
wrong_type_argument (Qinvalid_function, callback);
+ /* Check available file descriptors. */
+#ifdef HAVE_GETRLIMIT
+ if (! getrlimit (RLIMIT_NOFILE, &rlim))
+ maxfd = rlim.rlim_cur;
+ else
+#endif /* HAVE_GETRLIMIT */
+ maxfd = 256;
+
+ /* We assume 50 file descriptors are sufficient for the rest of Emacs. */
+ if ((maxfd - 50) < XINT (Flength (watch_list)))
+ xsignal2
+ (Qfile_notify_error,
+ build_string ("File watching not possible, no file descriptor left"),
+ Flength (watch_list));
+
if (kqueuefd < 0)
{
/* Create kqueue descriptor. */
/* Open file. */
file = ENCODE_FILE (file);
- fd = emacs_open (SSDATA (file), O_RDONLY, 0);
+ oflags = O_NONBLOCK;
+#if O_EVTONLY
+ oflags |= O_EVTONLY;
+#else
+ oflags |= O_RDONLY;
+#endif
+#if O_SYMLINK
+ oflags |= O_SYMLINK;
+#else
+ oflags |= O_NOFOLLOW;
+#endif
+ fd = emacs_open (SSDATA (file), oflags, 0);
if (fd == -1)
report_file_error ("File cannot be opened", file);
if (! NILP (Fmember (Qrename, flags))) fflags |= NOTE_RENAME;
/* Register event. */
- EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
+ EV_SET (&kev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR,
fflags, 0, NULL);
- if (kevent (kqueuefd, &ev, 1, NULL, 0, NULL) < 0) {
+ if (kevent (kqueuefd, &kev, 1, NULL, 0, NULL) < 0) {
emacs_close (fd);
report_file_error ("Cannot watch file", file);
}
#endif /* HAVE_KQUEUE */
-/* TODO
- * Add FILE1 in case of `rename'. */
-
/* PROBLEMS
* https://bugs.launchpad.net/ubuntu/+source/libkqueue/+bug/1514837
prevents tests on Ubuntu. */