279 lines
7.1 KiB
C
279 lines
7.1 KiB
C
/* -*- mode: C; c-file-style: "gnu" -*- */
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/* dir-watch-inotify.c OS specific directory change notification for message bus
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*
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* Copyright (C) 2003 Red Hat, Inc.
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* (c) 2006 Mandriva
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*
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* Licensed under the Academic Free License version 2.1
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*/
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#include <config.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <sys/inotify.h>
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#include <sys/types.h>
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#include <signal.h>
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#include <errno.h>
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#include <dbus/dbus-internals.h>
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#include <dbus/dbus-list.h>
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#include <dbus/dbus-watch.h>
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#include "dir-watch.h"
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#define MAX_DIRS_TO_WATCH 128
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#define INOTIFY_EVENT_SIZE (sizeof(struct inotify_event))
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#define INOTIFY_BUF_LEN (1024 * (INOTIFY_EVENT_SIZE + 16))
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/* use a static array to avoid handling OOM */
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static int wds[MAX_DIRS_TO_WATCH];
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static char *dirs[MAX_DIRS_TO_WATCH];
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static int num_wds = 0;
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static int inotify_fd = -1;
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static DBusWatch *watch = NULL;
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static DBusLoop *loop = NULL;
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static dbus_bool_t
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_handle_inotify_watch (DBusWatch *passed_watch, unsigned int flags, void *data)
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{
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char buffer[INOTIFY_BUF_LEN];
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ssize_t ret = 0;
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int i = 0;
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pid_t pid;
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dbus_bool_t have_change = FALSE;
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ret = read (inotify_fd, buffer, INOTIFY_BUF_LEN);
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if (ret < 0)
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_dbus_verbose ("Error reading inotify event: '%s'\n", _dbus_strerror(errno));
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else if (!ret)
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_dbus_verbose ("Error reading inotify event: buffer too small\n");
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while (i < ret)
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{
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struct inotify_event *ev;
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pid = _dbus_getpid ();
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ev = (struct inotify_event *) &buffer[i];
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i += INOTIFY_EVENT_SIZE + ev->len;
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#ifdef DBUS_ENABLE_VERBOSE_MODE
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if (ev->len)
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_dbus_verbose ("event name: '%s'\n", ev->name);
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_dbus_verbose ("inotify event: wd=%d mask=%u cookie=%u len=%u\n", ev->wd, ev->mask, ev->cookie, ev->len);
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#endif
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_dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n");
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have_change = TRUE;
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}
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if (have_change)
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(void) kill (pid, SIGHUP);
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return TRUE;
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}
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#include <stdio.h>
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static void
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_set_watched_dirs_internal (DBusList **directories)
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{
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int new_wds[MAX_DIRS_TO_WATCH];
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char *new_dirs[MAX_DIRS_TO_WATCH];
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DBusList *link;
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int i, j, wd;
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for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
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{
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new_wds[i] = -1;
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new_dirs[i] = NULL;
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}
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i = 0;
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link = _dbus_list_get_first_link (directories);
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while (link != NULL)
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{
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new_dirs[i++] = (char *)link->data;
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link = _dbus_list_get_next_link (directories, link);
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}
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/* Look for directories in both the old and new sets, if
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* we find one, move its data into the new set.
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*/
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for (i = 0; new_dirs[i]; i++)
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{
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for (j = 0; j < num_wds; j++)
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{
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if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
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{
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new_wds[i] = wds[j];
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new_dirs[i] = dirs[j];
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wds[j] = -1;
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dirs[j] = NULL;
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break;
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}
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}
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}
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/* Any directories we find in "wds" with a nonzero fd must
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* not be in the new set, so perform cleanup now.
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*/
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for (j = 0; j < num_wds; j++)
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{
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if (wds[j] != -1)
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{
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inotify_rm_watch (inotify_fd, wds[j]);
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dbus_free (dirs[j]);
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wds[j] = -1;
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dirs[j] = NULL;
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}
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}
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for (i = 0; new_dirs[i]; i++)
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{
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if (new_wds[i] == -1)
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{
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/* FIXME - less lame error handling for failing to add a watch; we may need to sleep. */
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wd = inotify_add_watch (inotify_fd, new_dirs[i], IN_CLOSE_WRITE | IN_DELETE | IN_MOVED_TO | IN_MOVED_FROM);
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if (wd < 0)
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{
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/* Not all service directories need to exist. */
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if (errno != ENOENT)
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{
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_dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
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goto out;
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}
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else
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{
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new_wds[i] = -1;
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new_dirs[i] = NULL;
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continue;
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}
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}
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new_wds[i] = wd;
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new_dirs[i] = _dbus_strdup (new_dirs[i]);
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if (!new_dirs[i])
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{
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/* FIXME have less lame handling for OOM, we just silently fail to
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* watch. (In reality though, the whole OOM handling in dbus is stupid
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* but we won't go into that in this comment =) )
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*/
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inotify_rm_watch (inotify_fd, wd);
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new_wds[i] = -1;
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}
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}
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}
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num_wds = i;
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for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
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{
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wds[i] = new_wds[i];
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dirs[i] = new_dirs[i];
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}
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out:;
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}
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#include <stdio.h>
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static void
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_shutdown_inotify (void *data)
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{
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DBusList *empty = NULL;
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if (inotify_fd == -1)
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return;
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_set_watched_dirs_internal (&empty);
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if (watch != NULL)
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{
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_dbus_loop_remove_watch (loop, watch);
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_dbus_watch_invalidate (watch);
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_dbus_watch_unref (watch);
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_dbus_loop_unref (loop);
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}
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watch = NULL;
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loop = NULL;
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close (inotify_fd);
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inotify_fd = -1;
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}
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static int
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_init_inotify (BusContext *context)
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{
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int ret = 0;
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if (inotify_fd == -1)
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{
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#ifdef HAVE_INOTIFY_INIT1
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inotify_fd = inotify_init1 (IN_CLOEXEC);
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/* This ensures we still run on older Linux kernels.
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* https://bugs.freedesktop.org/show_bug.cgi?id=23957
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*/
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if (inotify_fd < 0)
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inotify_fd = inotify_init ();
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#else
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inotify_fd = inotify_init ();
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#endif
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if (inotify_fd <= 0)
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{
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_dbus_warn ("Cannot initialize inotify\n");
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goto out;
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}
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loop = bus_context_get_loop (context);
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_dbus_loop_ref (loop);
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watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE,
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_handle_inotify_watch, NULL, NULL);
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if (watch == NULL)
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{
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_dbus_warn ("Unable to create inotify watch\n");
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goto out;
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}
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if (!_dbus_loop_add_watch (loop, watch))
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{
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_dbus_warn ("Unable to add reload watch to main loop");
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_dbus_watch_unref (watch);
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watch = NULL;
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goto out;
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}
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if (!_dbus_register_shutdown_func (_shutdown_inotify, NULL))
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{
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_dbus_warn ("Unable to register shutdown func");
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_dbus_watch_unref (watch);
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watch = NULL;
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goto out;
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}
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}
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ret = 1;
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out:
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return ret;
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}
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void
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bus_set_watched_dirs (BusContext *context, DBusList **directories)
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{
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if (!_init_inotify (context))
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return;
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_set_watched_dirs_internal (directories);
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}
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