bus/dir-watch-inotify.c - platform/external/dbus - Git at Google

 /* -*- mode: C; c-file-style: "gnu" -*- */
 /* dir-watch-inotify.c  OS specific directory change notification for message bus
  *
  * Copyright (C) 2003 Red Hat, Inc.
  *           (c) 2006 Mandriva
  *
  * Licensed under the Academic Free License version 2.1
  *
  * This program 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 2 of the License, or
  * (at your option) any later version.
  *
  * This program 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 this program; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  *
  */

 #include <config.h>

 #include <stdlib.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/inotify.h>
 #include <sys/types.h>
 #include <signal.h>
 #include <errno.h>

 #include <dbus/dbus-internals.h>
 #include <dbus/dbus-list.h>
 #include <dbus/dbus-watch.h>
 #include "dir-watch.h"

 #define MAX_DIRS_TO_WATCH 128
 #define INOTIFY_EVENT_SIZE (sizeof(struct inotify_event))
 #define INOTIFY_BUF_LEN (1024 * (INOTIFY_EVENT_SIZE + 16))

 /* use a static array to avoid handling OOM */
 static int wds[MAX_DIRS_TO_WATCH];
 static char *dirs[MAX_DIRS_TO_WATCH];
 static int num_wds = 0;
 static int inotify_fd = -1;
 static DBusWatch *watch = NULL;
 static DBusLoop *loop = NULL;

 static dbus_bool_t
 _handle_inotify_watch (DBusWatch *passed_watch, unsigned int flags, void *data)
 {
   char buffer[INOTIFY_BUF_LEN];
   ssize_t ret = 0;
   int i = 0;
   pid_t pid;
   dbus_bool_t have_change = FALSE;

   ret = read (inotify_fd, buffer, INOTIFY_BUF_LEN);
   if (ret < 0)
     _dbus_verbose ("Error reading inotify event: '%s'\n", _dbus_strerror(errno));
   else if (!ret)
     _dbus_verbose ("Error reading inotify event: buffer too small\n");

   while (i < ret)
     {
       struct inotify_event *ev;
       pid = _dbus_getpid ();

       ev = (struct inotify_event *) &buffer[i];
       i += INOTIFY_EVENT_SIZE + ev->len;
 #ifdef DBUS_ENABLE_VERBOSE_MODE
       if (ev->len)
         _dbus_verbose ("event name: '%s'\n", ev->name);
       _dbus_verbose ("inotify event: wd=%d mask=%u cookie=%u len=%u\n", ev->wd, ev->mask, ev->cookie, ev->len);
 #endif
       _dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n");
       have_change = TRUE;
     }
   if (have_change)
     (void) kill (pid, SIGHUP);

   return TRUE;
 }

 #include <stdio.h>

 static void
 _set_watched_dirs_internal (DBusList **directories)
 {
   int new_wds[MAX_DIRS_TO_WATCH];
   char *new_dirs[MAX_DIRS_TO_WATCH];
   DBusList *link;
   int i, j, wd;

   for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
     {
       new_wds[i] = -1;
       new_dirs[i] = NULL;
     }

   i = 0;
   link = _dbus_list_get_first_link (directories);
   while (link != NULL)
     {
       new_dirs[i++] = (char *)link->data;
       link = _dbus_list_get_next_link (directories, link);
     }

   /* Look for directories in both the old and new sets, if
    * we find one, move its data into the new set.
    */
   for (i = 0; new_dirs[i]; i++)
     {
       for (j = 0; j < num_wds; j++)
         {
           if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
             {
               new_wds[i] = wds[j];
               new_dirs[i] = dirs[j];
               wds[j] = -1;
               dirs[j] = NULL;
               break;
             }
         }
     }

   /* Any directories we find in "wds" with a nonzero fd must
    * not be in the new set, so perform cleanup now.
    */
   for (j = 0; j < num_wds; j++)
     {
       if (wds[j] != -1)
         {
           inotify_rm_watch (inotify_fd, wds[j]);
           dbus_free (dirs[j]);
           wds[j] = -1;
           dirs[j] = NULL;
         }
     }

   for (i = 0; new_dirs[i]; i++)
     {
       if (new_wds[i] == -1)
         {
           /* FIXME - less lame error handling for failing to add a watch; we may need to sleep. */
           wd = inotify_add_watch (inotify_fd, new_dirs[i], IN_CLOSE_WRITE | IN_DELETE | IN_MOVED_TO | IN_MOVED_FROM);
           if (wd < 0)
             {
               /* Not all service directories need to exist. */
               if (errno != ENOENT)
                 {
                   _dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
                   goto out;
                 }
               else
                 {
                   new_wds[i] = -1;
                   new_dirs[i] = NULL;
                   continue;
                 }
             }
           new_wds[i] = wd;
           new_dirs[i] = _dbus_strdup (new_dirs[i]);
           if (!new_dirs[i])
             {
               /* FIXME have less lame handling for OOM, we just silently fail to
                * watch.  (In reality though, the whole OOM handling in dbus is stupid
                * but we won't go into that in this comment =) )
                */
               inotify_rm_watch (inotify_fd, wd);
               new_wds[i] = -1;
             }
         }
     }

   num_wds = i;

   for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
     {
       wds[i] = new_wds[i];
       dirs[i] = new_dirs[i];
     }

  out:;
 }

 #include <stdio.h>
 static void
 _shutdown_inotify (void *data)
 {
   DBusList *empty = NULL;

   if (inotify_fd == -1)
     return;

   _set_watched_dirs_internal (&empty);

   if (watch != NULL)
     {
       _dbus_loop_remove_watch (loop, watch);
       _dbus_watch_invalidate (watch);
       _dbus_watch_unref (watch);
       _dbus_loop_unref (loop);
     }
   watch = NULL;
   loop = NULL;

   close (inotify_fd);
   inotify_fd = -1;
 }

 static int
 _init_inotify (BusContext *context)
 {
   int ret = 0;

   if (inotify_fd == -1)
     {
 #ifdef HAVE_INOTIFY_INIT1
       inotify_fd = inotify_init1 (IN_CLOEXEC);
       /* This ensures we still run on older Linux kernels.
        * https://bugs.freedesktop.org/show_bug.cgi?id=23957
        */
       if (inotify_fd < 0)
         inotify_fd = inotify_init ();
 #else
       inotify_fd = inotify_init ();
 #endif
       if (inotify_fd <= 0)
         {
           _dbus_warn ("Cannot initialize inotify\n");
           goto out;
         }
       loop = bus_context_get_loop (context);
       _dbus_loop_ref (loop);

       watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE,
                                _handle_inotify_watch, NULL, NULL);

       if (watch == NULL)
         {
           _dbus_warn ("Unable to create inotify watch\n");
           goto out;
         }

       if (!_dbus_loop_add_watch (loop, watch))
         {
           _dbus_warn ("Unable to add reload watch to main loop");
           _dbus_watch_unref (watch);
           watch = NULL;
           goto out;
         }

       if (!_dbus_register_shutdown_func (_shutdown_inotify, NULL))
       {
           _dbus_warn ("Unable to register shutdown func");
           _dbus_watch_unref (watch);
           watch = NULL;
           goto out;
       }
     }

   ret = 1;

 out:
   return ret;
 }

 void
 bus_set_watched_dirs (BusContext *context, DBusList **directories)
 {
   if (!_init_inotify (context))
     return;

   _set_watched_dirs_internal (directories);
 }
	/* -- mode: C; c-file-style: "gnu" -- */
	/* dir-watch-inotify.c OS specific directory change notification for message bus
	*
	* Copyright (C) 2003 Red Hat, Inc.
	* (c) 2006 Mandriva
	*
	* Licensed under the Academic Free License version 2.1
	*
	* This program 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 2 of the License, or
	* (at your option) any later version.
	*
	* This program 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 this program; if not, write to the Free Software
	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	*
	*/

	#include <config.h>

	#include <stdlib.h>
	#include <unistd.h>
	#include <fcntl.h>
	#include <sys/inotify.h>
	#include <sys/types.h>
	#include <signal.h>
	#include <errno.h>

	#include <dbus/dbus-internals.h>
	#include <dbus/dbus-list.h>
	#include <dbus/dbus-watch.h>
	#include "dir-watch.h"

	#define MAX_DIRS_TO_WATCH 128
	#define INOTIFY_EVENT_SIZE (sizeof(struct inotify_event))
	#define INOTIFY_BUF_LEN (1024 * (INOTIFY_EVENT_SIZE + 16))

	/* use a static array to avoid handling OOM */
	static int wds[MAX_DIRS_TO_WATCH];
	static char *dirs[MAX_DIRS_TO_WATCH];
	static int num_wds = 0;
	static int inotify_fd = -1;
	static DBusWatch *watch = NULL;
	static DBusLoop *loop = NULL;

	static dbus_bool_t
	_handle_inotify_watch (DBusWatch passed_watch, unsigned int flags, void data)
	{
	char buffer[INOTIFY_BUF_LEN];
	ssize_t ret = 0;
	int i = 0;
	pid_t pid;
	dbus_bool_t have_change = FALSE;

	ret = read (inotify_fd, buffer, INOTIFY_BUF_LEN);
	if (ret < 0)
	_dbus_verbose ("Error reading inotify event: '%s'\n", _dbus_strerror(errno));
	else if (!ret)
	_dbus_verbose ("Error reading inotify event: buffer too small\n");

	while (i < ret)
	{
	struct inotify_event *ev;
	pid = _dbus_getpid ();

	ev = (struct inotify_event *) &buffer[i];
	i += INOTIFY_EVENT_SIZE + ev->len;
	#ifdef DBUS_ENABLE_VERBOSE_MODE
	if (ev->len)
	_dbus_verbose ("event name: '%s'\n", ev->name);
	_dbus_verbose ("inotify event: wd=%d mask=%u cookie=%u len=%u\n", ev->wd, ev->mask, ev->cookie, ev->len);
	#endif
	_dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n");
	have_change = TRUE;
	}
	if (have_change)
	(void) kill (pid, SIGHUP);

	return TRUE;
	}

	#include <stdio.h>

	static void
	_set_watched_dirs_internal (DBusList **directories)
	{
	int new_wds[MAX_DIRS_TO_WATCH];
	char *new_dirs[MAX_DIRS_TO_WATCH];
	DBusList *link;
	int i, j, wd;

	for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
	{
	new_wds[i] = -1;
	new_dirs[i] = NULL;
	}

	i = 0;
	link = _dbus_list_get_first_link (directories);
	while (link != NULL)
	{
	new_dirs[i++] = (char *)link->data;
	link = _dbus_list_get_next_link (directories, link);
	}

	/* Look for directories in both the old and new sets, if
	* we find one, move its data into the new set.
	*/
	for (i = 0; new_dirs[i]; i++)
	{
	for (j = 0; j < num_wds; j++)
	{
	if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
	{
	new_wds[i] = wds[j];
	new_dirs[i] = dirs[j];
	wds[j] = -1;
	dirs[j] = NULL;
	break;
	}
	}
	}

	/* Any directories we find in "wds" with a nonzero fd must
	* not be in the new set, so perform cleanup now.
	*/
	for (j = 0; j < num_wds; j++)
	{
	if (wds[j] != -1)
	{
	inotify_rm_watch (inotify_fd, wds[j]);
	dbus_free (dirs[j]);
	wds[j] = -1;
	dirs[j] = NULL;
	}
	}

	for (i = 0; new_dirs[i]; i++)
	{
	if (new_wds[i] == -1)
	{
	/* FIXME - less lame error handling for failing to add a watch; we may need to sleep. */
	wd = inotify_add_watch (inotify_fd, new_dirs[i], IN_CLOSE_WRITE \| IN_DELETE \| IN_MOVED_TO \| IN_MOVED_FROM);
	if (wd < 0)
	{
	/* Not all service directories need to exist. */
	if (errno != ENOENT)
	{
	_dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
	goto out;
	}
	else
	{
	new_wds[i] = -1;
	new_dirs[i] = NULL;
	continue;
	}
	}
	new_wds[i] = wd;
	new_dirs[i] = _dbus_strdup (new_dirs[i]);
	if (!new_dirs[i])
	{
	/* FIXME have less lame handling for OOM, we just silently fail to
	* watch. (In reality though, the whole OOM handling in dbus is stupid
	* but we won't go into that in this comment =) )
	*/
	inotify_rm_watch (inotify_fd, wd);
	new_wds[i] = -1;
	}
	}
	}

	num_wds = i;

	for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
	{
	wds[i] = new_wds[i];
	dirs[i] = new_dirs[i];
	}

	out:;
	}

	#include <stdio.h>
	static void
	_shutdown_inotify (void *data)
	{
	DBusList *empty = NULL;

	if (inotify_fd == -1)
	return;

	_set_watched_dirs_internal (&empty);

	if (watch != NULL)
	{
	_dbus_loop_remove_watch (loop, watch);
	_dbus_watch_invalidate (watch);
	_dbus_watch_unref (watch);
	_dbus_loop_unref (loop);
	}
	watch = NULL;
	loop = NULL;

	close (inotify_fd);
	inotify_fd = -1;
	}

	static int
	_init_inotify (BusContext *context)
	{
	int ret = 0;

	if (inotify_fd == -1)
	{
	#ifdef HAVE_INOTIFY_INIT1
	inotify_fd = inotify_init1 (IN_CLOEXEC);
	/* This ensures we still run on older Linux kernels.
	* https://bugs.freedesktop.org/show_bug.cgi?id=23957
	*/
	if (inotify_fd < 0)
	inotify_fd = inotify_init ();
	#else
	inotify_fd = inotify_init ();
	#endif
	if (inotify_fd <= 0)
	{
	_dbus_warn ("Cannot initialize inotify\n");
	goto out;
	}
	loop = bus_context_get_loop (context);
	_dbus_loop_ref (loop);

	watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE,
	_handle_inotify_watch, NULL, NULL);

	if (watch == NULL)
	{
	_dbus_warn ("Unable to create inotify watch\n");
	goto out;
	}

	if (!_dbus_loop_add_watch (loop, watch))
	{
	_dbus_warn ("Unable to add reload watch to main loop");
	_dbus_watch_unref (watch);
	watch = NULL;
	goto out;
	}

	if (!_dbus_register_shutdown_func (_shutdown_inotify, NULL))
	{
	_dbus_warn ("Unable to register shutdown func");
	_dbus_watch_unref (watch);
	watch = NULL;
	goto out;
	}
	}

	ret = 1;

	out:
	return ret;
	}

	void
	bus_set_watched_dirs (BusContext context, DBusList *directories)
	{
	if (!_init_inotify (context))
	return;

	_set_watched_dirs_internal (directories);
	}