2 * Copyright (C) 2003-2010 Kay Sievers <kay.sievers@vrfy.org>
4 * This program is free software: you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation, either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program. If not, see <http://www.gnu.org/licenses/>.
30 #include <sys/types.h>
34 #define TMP_FILE_EXT ".udev-tmp"
36 static int node_symlink(struct udev *udev, const char *node, const char *slink)
39 char target[UTIL_PATH_SIZE];
42 char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
47 /* use relative link */
49 while (node[i] && (node[i] == slink[i])) {
56 while (slink[i] != '\0') {
58 l = util_strpcpy(&s, l, "../");
61 l = util_strscpy(s, l, &node[tail]);
67 /* preserve link with correct target, do not replace node of other device */
68 if (lstat(slink, &stats) == 0) {
69 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
72 info(udev, "found existing node instead of symlink '%s'\n", slink);
73 if (lstat(node, &stats2) == 0) {
74 if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
75 stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
76 info(udev, "replace device node '%s' with symlink to our node '%s'\n",
79 err(udev, "device node '%s' already exists, "
80 "link to '%s' will not overwrite it\n",
85 } else if (S_ISLNK(stats.st_mode)) {
86 char buf[UTIL_PATH_SIZE];
89 dbg(udev, "found existing symlink '%s'\n", slink);
90 len = readlink(slink, buf, sizeof(buf));
91 if (len > 0 && len < (int)sizeof(buf)) {
93 if (strcmp(target, buf) == 0) {
94 info(udev, "preserve already existing symlink '%s' to '%s'\n",
96 udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
97 utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
103 info(udev, "creating symlink '%s' to '%s'\n", slink, target);
105 err = util_create_path_selinux(udev, slink);
106 if (err != 0 && err != -ENOENT)
108 udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
109 err = symlink(target, slink);
112 udev_selinux_resetfscreatecon(udev);
113 } while (err == -ENOENT);
118 info(udev, "atomically replace '%s'\n", slink);
119 util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
122 err = util_create_path_selinux(udev, slink_tmp);
123 if (err != 0 && err != -ENOENT)
125 udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
126 err = symlink(target, slink_tmp);
129 udev_selinux_resetfscreatecon(udev);
130 } while (err == -ENOENT);
132 err(udev, "symlink '%s' '%s' failed: %m\n", target, slink_tmp);
135 err = rename(slink_tmp, slink);
137 err(udev, "rename '%s' '%s' failed: %m\n", slink_tmp, slink);
144 /* find device node of device with highest priority */
145 static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
147 struct udev *udev = udev_device_get_udev(dev);
150 const char *target = NULL;
153 priority = udev_device_get_devlink_priority(dev);
154 util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
158 dir = opendir(stackdir);
162 struct udev_device *dev_db;
166 if (dent == NULL || dent->d_name[0] == '\0')
168 if (dent->d_name[0] == '.')
171 info(udev, "found '%s' claiming '%s'\n", dent->d_name, stackdir);
173 /* did we find ourself? */
174 if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
177 dev_db = udev_device_new_from_id_filename(udev, dent->d_name);
178 if (dev_db != NULL) {
181 devnode = udev_device_get_devnode(dev_db);
182 if (devnode != NULL) {
183 dbg(udev, "compare priority of '%s'(%i) > '%s'(%i)\n", target, priority,
184 udev_device_get_devnode(dev_db), udev_device_get_devlink_priority(dev_db));
185 if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
186 info(udev, "'%s' claims priority %i for '%s'\n",
187 udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
188 priority = udev_device_get_devlink_priority(dev_db);
189 util_strscpy(buf, bufsize, devnode);
193 udev_device_unref(dev_db);
200 /* manage "stack of names" with possibly specified device priorities */
201 static void link_update(struct udev_device *dev, const char *slink, bool add)
203 struct udev *udev = udev_device_get_udev(dev);
204 char name_enc[UTIL_PATH_SIZE];
205 char filename[UTIL_PATH_SIZE * 2];
206 char dirname[UTIL_PATH_SIZE];
208 char buf[UTIL_PATH_SIZE];
210 dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
212 util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
213 util_strscpyl(dirname, sizeof(dirname), udev_get_run_path(udev), "/links/", name_enc, NULL);
214 util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
217 dbg(udev, "removing index: '%s'\n", filename);
218 if (unlink(filename) == 0)
222 target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
223 if (target == NULL) {
224 info(udev, "no reference left, remove '%s'\n", slink);
225 if (unlink(slink) == 0)
226 util_delete_path(udev, slink);
228 info(udev, "creating link '%s' to '%s'\n", slink, target);
229 node_symlink(udev, target, slink);
235 dbg(udev, "creating index: '%s'\n", filename);
239 err = util_create_path(udev, filename);
240 if (err != 0 && err != -ENOENT)
242 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
247 } while (err == -ENOENT);
251 void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old)
253 struct udev *udev = udev_device_get_udev(dev);
254 struct udev_list_entry *list_entry;
256 /* update possible left-over symlinks */
257 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) {
258 const char *name = udev_list_entry_get_name(list_entry);
259 struct udev_list_entry *list_entry_current;
262 /* check if old link name still belongs to this device */
264 udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
265 const char *name_current = udev_list_entry_get_name(list_entry_current);
267 if (strcmp(name, name_current) == 0) {
275 info(udev, "update old name, '%s' no longer belonging to '%s'\n",
276 name, udev_device_get_devpath(dev));
277 link_update(dev, name, 0);
281 static int node_fixup(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
283 struct udev *udev = udev_device_get_udev(dev);
284 const char *devnode = udev_device_get_devnode(dev);
285 dev_t devnum = udev_device_get_devnum(dev);
289 if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
294 if (lstat(devnode, &stats) != 0) {
296 info(udev, "can not stat() node '%s' (%m)\n", devnode);
300 if (((stats.st_mode & S_IFMT) != (mode & S_IFMT)) || (stats.st_rdev != devnum)) {
302 info(udev, "found node '%s' with non-matching devnum %s, skip handling\n",
303 udev_device_get_devnode(dev), udev_device_get_id_filename(dev));
307 if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
308 info(udev, "set permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
309 chmod(devnode, mode);
310 chown(devnode, uid, gid);
312 info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
316 * Set initial selinux file context only on add events.
317 * We set the proper context on bootup (triger) or for newly
318 * added devices, but we don't change it later, in case
319 * something else has set a custom context in the meantime.
321 if (strcmp(udev_device_get_action(dev), "add") == 0)
322 udev_selinux_lsetfilecon(udev, devnode, mode);
324 /* always update timestamp when we re-use the node, like on media change events */
325 utimensat(AT_FDCWD, devnode, NULL, 0);
330 int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
332 struct udev *udev = udev_device_get_udev(dev);
333 char filename[UTIL_PATH_SIZE];
334 struct udev_list_entry *list_entry;
337 info(udev, "handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d\n",
338 udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid);
340 err = node_fixup(dev, mode, uid, gid);
344 /* always add /dev/{block,char}/$major:$minor */
345 snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
346 udev_get_dev_path(udev),
347 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
348 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
349 node_symlink(udev, udev_device_get_devnode(dev), filename);
351 /* create/update symlinks, add symlinks to name index */
352 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
353 if (udev_list_entry_get_num(list_entry))
354 /* simple unmanaged link name */
355 node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
357 link_update(dev, udev_list_entry_get_name(list_entry), 1);
363 int udev_node_remove(struct udev_device *dev)
365 struct udev *udev = udev_device_get_udev(dev);
366 struct udev_list_entry *list_entry;
369 struct udev_device *dev_check;
370 char filename[UTIL_PATH_SIZE];
373 /* remove/update symlinks, remove symlinks from name index */
374 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
375 link_update(dev, udev_list_entry_get_name(list_entry), 0);
377 /* remove /dev/{block,char}/$major:$minor */
378 snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
379 udev_get_dev_path(udev),
380 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
381 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));