Emeric Vigier | 2f62582 | 2012-08-06 11:09:52 -0400 | [diff] [blame] | 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 |
| 53 | _inotify_watch_callback (DBusWatch *watch, unsigned int condition, void *data) |
| 54 | { |
| 55 | return dbus_watch_handle (watch, condition); |
| 56 | } |
| 57 | |
| 58 | static dbus_bool_t |
| 59 | _handle_inotify_watch (DBusWatch *passed_watch, unsigned int flags, void *data) |
| 60 | { |
| 61 | char buffer[INOTIFY_BUF_LEN]; |
| 62 | ssize_t ret = 0; |
| 63 | int i = 0; |
| 64 | pid_t pid; |
| 65 | dbus_bool_t have_change = FALSE; |
| 66 | |
| 67 | ret = read (inotify_fd, buffer, INOTIFY_BUF_LEN); |
| 68 | if (ret < 0) |
| 69 | _dbus_verbose ("Error reading inotify event: '%s'\n", _dbus_strerror(errno)); |
| 70 | else if (!ret) |
| 71 | _dbus_verbose ("Error reading inotify event: buffer too small\n"); |
| 72 | |
| 73 | while (i < ret) |
| 74 | { |
| 75 | struct inotify_event *ev; |
| 76 | pid = _dbus_getpid (); |
| 77 | |
| 78 | ev = (struct inotify_event *) &buffer[i]; |
| 79 | i += INOTIFY_EVENT_SIZE + ev->len; |
| 80 | #ifdef DBUS_ENABLE_VERBOSE_MODE |
| 81 | if (ev->len) |
| 82 | _dbus_verbose ("event name: '%s'\n", ev->name); |
| 83 | _dbus_verbose ("inotify event: wd=%d mask=%u cookie=%u len=%u\n", ev->wd, ev->mask, ev->cookie, ev->len); |
| 84 | #endif |
| 85 | _dbus_verbose ("Sending SIGHUP signal on reception of a inotify event\n"); |
| 86 | have_change = TRUE; |
| 87 | } |
| 88 | if (have_change) |
| 89 | (void) kill (pid, SIGHUP); |
| 90 | |
| 91 | return TRUE; |
| 92 | } |
| 93 | |
| 94 | #include <stdio.h> |
| 95 | |
| 96 | static void |
| 97 | _set_watched_dirs_internal (DBusList **directories) |
| 98 | { |
| 99 | int new_wds[MAX_DIRS_TO_WATCH]; |
| 100 | char *new_dirs[MAX_DIRS_TO_WATCH]; |
| 101 | DBusList *link; |
| 102 | int i, j, wd; |
| 103 | |
| 104 | for (i = 0; i < MAX_DIRS_TO_WATCH; i++) |
| 105 | { |
| 106 | new_wds[i] = -1; |
| 107 | new_dirs[i] = NULL; |
| 108 | } |
| 109 | |
| 110 | i = 0; |
| 111 | link = _dbus_list_get_first_link (directories); |
| 112 | while (link != NULL) |
| 113 | { |
| 114 | new_dirs[i++] = (char *)link->data; |
| 115 | link = _dbus_list_get_next_link (directories, link); |
| 116 | } |
| 117 | |
| 118 | /* Look for directories in both the old and new sets, if |
| 119 | * we find one, move its data into the new set. |
| 120 | */ |
| 121 | for (i = 0; new_dirs[i]; i++) |
| 122 | { |
| 123 | for (j = 0; j < num_wds; j++) |
| 124 | { |
| 125 | if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0) |
| 126 | { |
| 127 | new_wds[i] = wds[j]; |
| 128 | new_dirs[i] = dirs[j]; |
| 129 | wds[j] = -1; |
| 130 | dirs[j] = NULL; |
| 131 | break; |
| 132 | } |
| 133 | } |
| 134 | } |
| 135 | |
| 136 | /* Any directories we find in "wds" with a nonzero fd must |
| 137 | * not be in the new set, so perform cleanup now. |
| 138 | */ |
| 139 | for (j = 0; j < num_wds; j++) |
| 140 | { |
| 141 | if (wds[j] != -1) |
| 142 | { |
| 143 | inotify_rm_watch (inotify_fd, wds[j]); |
| 144 | dbus_free (dirs[j]); |
| 145 | wds[j] = -1; |
| 146 | dirs[j] = NULL; |
| 147 | } |
| 148 | } |
| 149 | |
| 150 | for (i = 0; new_dirs[i]; i++) |
| 151 | { |
| 152 | if (new_wds[i] == -1) |
| 153 | { |
| 154 | /* FIXME - less lame error handling for failing to add a watch; we may need to sleep. */ |
| 155 | wd = inotify_add_watch (inotify_fd, new_dirs[i], IN_CLOSE_WRITE | IN_DELETE | IN_MOVED_TO | IN_MOVED_FROM); |
| 156 | if (wd < 0) |
| 157 | { |
| 158 | /* Not all service directories need to exist. */ |
| 159 | if (errno != ENOENT) |
| 160 | { |
| 161 | _dbus_warn ("Cannot setup inotify for '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno)); |
| 162 | goto out; |
| 163 | } |
| 164 | else |
| 165 | { |
| 166 | new_wds[i] = -1; |
| 167 | new_dirs[i] = NULL; |
| 168 | continue; |
| 169 | } |
| 170 | } |
| 171 | new_wds[i] = wd; |
| 172 | new_dirs[i] = _dbus_strdup (new_dirs[i]); |
| 173 | if (!new_dirs[i]) |
| 174 | { |
| 175 | /* FIXME have less lame handling for OOM, we just silently fail to |
| 176 | * watch. (In reality though, the whole OOM handling in dbus is stupid |
| 177 | * but we won't go into that in this comment =) ) |
| 178 | */ |
| 179 | inotify_rm_watch (inotify_fd, wd); |
| 180 | new_wds[i] = -1; |
| 181 | } |
| 182 | } |
| 183 | } |
| 184 | |
| 185 | num_wds = i; |
| 186 | |
| 187 | for (i = 0; i < MAX_DIRS_TO_WATCH; i++) |
| 188 | { |
| 189 | wds[i] = new_wds[i]; |
| 190 | dirs[i] = new_dirs[i]; |
| 191 | } |
| 192 | |
| 193 | out:; |
| 194 | } |
| 195 | |
| 196 | #include <stdio.h> |
| 197 | static void |
| 198 | _shutdown_inotify (void *data) |
| 199 | { |
| 200 | DBusList *empty = NULL; |
| 201 | |
| 202 | if (inotify_fd == -1) |
| 203 | return; |
| 204 | |
| 205 | _set_watched_dirs_internal (&empty); |
| 206 | |
| 207 | close (inotify_fd); |
| 208 | inotify_fd = -1; |
| 209 | if (watch != NULL) |
| 210 | { |
| 211 | _dbus_loop_remove_watch (loop, watch, _inotify_watch_callback, NULL); |
| 212 | _dbus_watch_unref (watch); |
| 213 | _dbus_loop_unref (loop); |
| 214 | } |
| 215 | watch = NULL; |
| 216 | loop = NULL; |
| 217 | } |
| 218 | |
| 219 | static int |
| 220 | _init_inotify (BusContext *context) |
| 221 | { |
| 222 | int ret = 0; |
| 223 | |
| 224 | if (inotify_fd == -1) |
| 225 | { |
| 226 | #ifdef HAVE_INOTIFY_INIT1 |
| 227 | inotify_fd = inotify_init1 (IN_CLOEXEC); |
| 228 | /* This ensures we still run on older Linux kernels. |
| 229 | * https://bugs.freedesktop.org/show_bug.cgi?id=23957 |
| 230 | */ |
| 231 | if (inotify_fd < 0) |
| 232 | inotify_fd = inotify_init (); |
| 233 | #else |
| 234 | inotify_fd = inotify_init (); |
| 235 | #endif |
| 236 | if (inotify_fd <= 0) |
| 237 | { |
| 238 | _dbus_warn ("Cannot initialize inotify\n"); |
| 239 | goto out; |
| 240 | } |
| 241 | loop = bus_context_get_loop (context); |
| 242 | _dbus_loop_ref (loop); |
| 243 | |
| 244 | watch = _dbus_watch_new (inotify_fd, DBUS_WATCH_READABLE, TRUE, |
| 245 | _handle_inotify_watch, NULL, NULL); |
| 246 | |
| 247 | if (watch == NULL) |
| 248 | { |
| 249 | _dbus_warn ("Unable to create inotify watch\n"); |
| 250 | goto out; |
| 251 | } |
| 252 | |
| 253 | if (!_dbus_loop_add_watch (loop, watch, _inotify_watch_callback, |
| 254 | NULL, NULL)) |
| 255 | { |
| 256 | _dbus_warn ("Unable to add reload watch to main loop"); |
| 257 | _dbus_watch_unref (watch); |
| 258 | watch = NULL; |
| 259 | goto out; |
| 260 | } |
| 261 | |
| 262 | _dbus_register_shutdown_func (_shutdown_inotify, NULL); |
| 263 | } |
| 264 | |
| 265 | ret = 1; |
| 266 | |
| 267 | out: |
| 268 | return ret; |
| 269 | } |
| 270 | |
| 271 | void |
| 272 | bus_set_watched_dirs (BusContext *context, DBusList **directories) |
| 273 | { |
| 274 | if (!_init_inotify (context)) |
| 275 | return; |
| 276 | |
| 277 | _set_watched_dirs_internal (directories); |
| 278 | } |