1 /* -*- mode: C; c-file-style: "gnu" -*- */
2 /* dir-watch-inotify.c OS specific directory change notification for message bus
3 *
4 * Copyright (C) 2003 Red Hat, Inc.
5 * (c) 2006 Mandriva
6 *
7 * Licensed under the Academic Free License version 2.1
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
13 *
14 * This program is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
18 *
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 *
23 */
24
25 #include <config.h>
26
27 #include <stdlib.h>
28 #include <unistd.h>
29 #include <fcntl.h>
30 #include <sys/inotify.h>
31 #include <sys/types.h>
32 #include <signal.h>
33 #include <errno.h>
34
35 #include <dbus/dbus-internals.h>
36 #include <dbus/dbus-list.h>
37 #include <dbus/dbus-watch.h>
38 #include "dir-watch.h"
39
40 #define MAX_DIRS_TO_WATCH 128
41 #define INOTIFY_EVENT_SIZE (sizeof(struct inotify_event))
42 #define INOTIFY_BUF_LEN (1024 * (INOTIFY_EVENT_SIZE + 16))
43
44 /* use a static array to avoid handling OOM */
45 static int wds[MAX_DIRS_TO_WATCH];
46 static char *dirs[MAX_DIRS_TO_WATCH];
47 static int num_wds = 0;
48 static int inotify_fd = -1;
49 static DBusWatch *watch = NULL;
50 static DBusLoop *loop = NULL;
51
52 static dbus_bool_t
_handle_inotify_watch(DBusWatch * passed_watch,unsigned int flags,void * data)53 _handle_inotify_watch (DBusWatch *passed_watch, unsigned int flags, void *data)
54 {
55 char buffer[INOTIFY_BUF_LEN];
56 ssize_t ret = 0;
57 int i = 0;
58 pid_t pid;
59 dbus_bool_t have_change = FALSE;
60
61 ret = read (inotify_fd, buffer, INOTIFY_BUF_LEN);
62 if (ret < 0)
63 _dbus_verbose ("Error reading inotify event: '%s'\n", _dbus_strerror(errno));
64 else if (!ret)
65 _dbus_verbose ("Error reading inotify event: buffer too small\n");
66
67 while (i < ret)
68 {
69 struct inotify_event *ev;
70 pid = _dbus_getpid ();
71
72 ev = (struct inotify_event *) &buffer[i];
73 i += INOTIFY_EVENT_SIZE + ev->len;
74 #ifdef DBUS_ENABLE_VERBOSE_MODE
75 if (ev->len)
76 _dbus_verbose ("event name: '%s'\n", ev->name);
77 _dbus_verbose ("inotify event: wd=%d mask=%u cookie=%u len=%u\n", ev->wd, ev->mask, ev->cookie, ev->len);
78 #endif
79 _dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n");
80 have_change = TRUE;
81 }
82 if (have_change)
83 (void) kill (pid, SIGHUP);
84
85 return TRUE;
86 }
87
88 #include <stdio.h>
89
90 static void
_set_watched_dirs_internal(DBusList ** directories)91 _set_watched_dirs_internal (DBusList **directories)
92 {
93 int new_wds[MAX_DIRS_TO_WATCH];
94 char *new_dirs[MAX_DIRS_TO_WATCH];
95 DBusList *link;
96 int i, j, wd;
97
98 for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
99 {
100 new_wds[i] = -1;
101 new_dirs[i] = NULL;
102 }
103
104 i = 0;
105 link = _dbus_list_get_first_link (directories);
106 while (link != NULL)
107 {
108 new_dirs[i++] = (char *)link->data;
109 link = _dbus_list_get_next_link (directories, link);
110 }
111
112 /* Look for directories in both the old and new sets, if
113 * we find one, move its data into the new set.
114 */
115 for (i = 0; new_dirs[i]; i++)
116 {
117 for (j = 0; j < num_wds; j++)
118 {
119 if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0)
120 {
121 new_wds[i] = wds[j];
122 new_dirs[i] = dirs[j];
123 wds[j] = -1;
124 dirs[j] = NULL;
125 break;
126 }
127 }
128 }
129
130 /* Any directories we find in "wds" with a nonzero fd must
131 * not be in the new set, so perform cleanup now.
132 */
133 for (j = 0; j < num_wds; j++)
134 {
135 if (wds[j] != -1)
136 {
137 inotify_rm_watch (inotify_fd, wds[j]);
138 dbus_free (dirs[j]);
139 wds[j] = -1;
140 dirs[j] = NULL;
141 }
142 }
143
144 for (i = 0; new_dirs[i]; i++)
145 {
146 if (new_wds[i] == -1)
147 {
148 /* FIXME - less lame error handling for failing to add a watch; we may need to sleep. */
149 wd = inotify_add_watch (inotify_fd, new_dirs[i], IN_CLOSE_WRITE | IN_DELETE | IN_MOVED_TO | IN_MOVED_FROM);
150 if (wd < 0)
151 {
152 /* Not all service directories need to exist. */
153 if (errno != ENOENT)
154 {
155 _dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno));
156 goto out;
157 }
158 else
159 {
160 new_wds[i] = -1;
161 new_dirs[i] = NULL;
162 continue;
163 }
164 }
165 new_wds[i] = wd;
166 new_dirs[i] = _dbus_strdup (new_dirs[i]);
167 if (!new_dirs[i])
168 {
169 /* FIXME have less lame handling for OOM, we just silently fail to
170 * watch. (In reality though, the whole OOM handling in dbus is stupid
171 * but we won't go into that in this comment =) )
172 */
173 inotify_rm_watch (inotify_fd, wd);
174 new_wds[i] = -1;
175 }
176 }
177 }
178
179 num_wds = i;
180
181 for (i = 0; i < MAX_DIRS_TO_WATCH; i++)
182 {
183 wds[i] = new_wds[i];
184 dirs[i] = new_dirs[i];
185 }
186
187 out:;
188 }
189
190 #include <stdio.h>
191 static void
_shutdown_inotify(void * data)192 _shutdown_inotify (void *data)
193 {
194 DBusList *empty = NULL;
195
196 if (inotify_fd == -1)
197 return;
198
199 _set_watched_dirs_internal (&empty);
200
201 if (watch != NULL)
202 {
203 _dbus_loop_remove_watch (loop, watch);
204 _dbus_watch_invalidate (watch);
205 _dbus_watch_unref (watch);
206 _dbus_loop_unref (loop);
207 }
208 watch = NULL;
209 loop = NULL;
210
211 close (inotify_fd);
212 inotify_fd = -1;
213 }
214
215 static int
_init_inotify(BusContext * context)216 _init_inotify (BusContext *context)
217 {
218 int ret = 0;
219
220 if (inotify_fd == -1)
221 {
222 #ifdef HAVE_INOTIFY_INIT1
223 inotify_fd = inotify_init1 (IN_CLOEXEC);
224 /* This ensures we still run on older Linux kernels.
225 * https://bugs.freedesktop.org/show_bug.cgi?id=23957
226 */
227 if (inotify_fd < 0)
228 inotify_fd = inotify_init ();
229 #else
230 inotify_fd = inotify_init ();
231 #endif
232 if (inotify_fd <= 0)
233 {
234 _dbus_warn ("Cannot initialize inotify\n");
235 goto out;
236 }
237 loop = bus_context_get_loop (context);
238 _dbus_loop_ref (loop);
239
240 watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE,
241 _handle_inotify_watch, NULL, NULL);
242
243 if (watch == NULL)
244 {
245 _dbus_warn ("Unable to create inotify watch\n");
246 goto out;
247 }
248
249 if (!_dbus_loop_add_watch (loop, watch))
250 {
251 _dbus_warn ("Unable to add reload watch to main loop");
252 _dbus_watch_unref (watch);
253 watch = NULL;
254 goto out;
255 }
256
257 if (!_dbus_register_shutdown_func (_shutdown_inotify, NULL))
258 {
259 _dbus_warn ("Unable to register shutdown func");
260 _dbus_watch_unref (watch);
261 watch = NULL;
262 goto out;
263 }
264 }
265
266 ret = 1;
267
268 out:
269 return ret;
270 }
271
272 void
bus_set_watched_dirs(BusContext * context,DBusList ** directories)273 bus_set_watched_dirs (BusContext *context, DBusList **directories)
274 {
275 if (!_init_inotify (context))
276 return;
277
278 _set_watched_dirs_internal (directories);
279 }
280