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 log_debug("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 log_debug("replace device node '%s' with symlink to our node '%s'\n",
79 log_error("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 len = readlink(slink, buf, sizeof(buf));
90 if (len > 0 && len < (int)sizeof(buf)) {
92 if (strcmp(target, buf) == 0) {
93 log_debug("preserve already existing symlink '%s' to '%s'\n", slink, target);
94 label_fix(slink, true);
95 utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
101 log_debug("creating symlink '%s' to '%s'\n", slink, target);
103 err = mkdir_parents(slink, 0755);
104 if (err != 0 && err != -ENOENT)
106 label_context_set(slink, S_IFLNK);
107 err = symlink(target, slink);
110 label_context_clear();
111 } while (err == -ENOENT);
116 log_debug("atomically replace '%s'\n", slink);
117 util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
120 err = mkdir_parents(slink_tmp, 0755);
121 if (err != 0 && err != -ENOENT)
123 label_context_set(slink_tmp, S_IFLNK);
124 err = symlink(target, slink_tmp);
127 label_context_clear();
128 } while (err == -ENOENT);
130 log_error("symlink '%s' '%s' failed: %m\n", target, slink_tmp);
133 err = rename(slink_tmp, slink);
135 log_error("rename '%s' '%s' failed: %m\n", slink_tmp, slink);
142 /* find device node of device with highest priority */
143 static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
145 struct udev *udev = udev_device_get_udev(dev);
148 const char *target = NULL;
151 priority = udev_device_get_devlink_priority(dev);
152 util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
156 dir = opendir(stackdir);
160 struct udev_device *dev_db;
164 if (dent == NULL || dent->d_name[0] == '\0')
166 if (dent->d_name[0] == '.')
169 log_debug("found '%s' claiming '%s'\n", dent->d_name, stackdir);
171 /* did we find ourself? */
172 if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
175 dev_db = udev_device_new_from_id_filename(udev, dent->d_name);
176 if (dev_db != NULL) {
179 devnode = udev_device_get_devnode(dev_db);
180 if (devnode != NULL) {
181 if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
182 log_debug("'%s' claims priority %i for '%s'\n",
183 udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
184 priority = udev_device_get_devlink_priority(dev_db);
185 util_strscpy(buf, bufsize, devnode);
189 udev_device_unref(dev_db);
196 /* manage "stack of names" with possibly specified device priorities */
197 static void link_update(struct udev_device *dev, const char *slink, bool add)
199 struct udev *udev = udev_device_get_udev(dev);
200 char name_enc[UTIL_PATH_SIZE];
201 char filename[UTIL_PATH_SIZE * 2];
202 char dirname[UTIL_PATH_SIZE];
204 char buf[UTIL_PATH_SIZE];
206 util_path_encode(slink + strlen(TEST_PREFIX "/dev"), name_enc, sizeof(name_enc));
207 util_strscpyl(dirname, sizeof(dirname), TEST_PREFIX "/run/udev/links/", name_enc, NULL);
208 util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
210 if (!add && unlink(filename) == 0)
213 target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
214 if (target == NULL) {
215 log_debug("no reference left, remove '%s'\n", slink);
216 if (unlink(slink) == 0)
217 util_delete_path(udev, slink);
219 log_debug("creating link '%s' to '%s'\n", slink, target);
220 node_symlink(udev, target, slink);
229 err = mkdir_parents(filename, 0755);
230 if (err != 0 && err != -ENOENT)
232 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
237 } while (err == -ENOENT);
241 void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old)
243 struct udev_list_entry *list_entry;
245 /* update possible left-over symlinks */
246 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) {
247 const char *name = udev_list_entry_get_name(list_entry);
248 struct udev_list_entry *list_entry_current;
251 /* check if old link name still belongs to this device */
253 udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
254 const char *name_current = udev_list_entry_get_name(list_entry_current);
256 if (strcmp(name, name_current) == 0) {
264 log_debug("update old name, '%s' no longer belonging to '%s'\n",
265 name, udev_device_get_devpath(dev));
266 link_update(dev, name, 0);
270 static int node_fixup(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
272 const char *devnode = udev_device_get_devnode(dev);
273 dev_t devnum = udev_device_get_devnum(dev);
277 if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
282 if (lstat(devnode, &stats) != 0) {
284 log_debug("can not stat() node '%s' (%m)\n", devnode);
288 if (((stats.st_mode & S_IFMT) != (mode & S_IFMT)) || (stats.st_rdev != devnum)) {
290 log_debug("found node '%s' with non-matching devnum %s, skip handling\n",
291 udev_device_get_devnode(dev), udev_device_get_id_filename(dev));
295 if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
296 log_debug("set permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
297 chmod(devnode, mode);
298 chown(devnode, uid, gid);
300 log_debug("preserve permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
304 * Set initial selinux file context only on add events.
305 * We set the proper context on bootup (triger) or for newly
306 * added devices, but we don't change it later, in case
307 * something else has set a custom context in the meantime.
309 if (strcmp(udev_device_get_action(dev), "add") == 0)
310 label_fix(devnode, true);
312 /* always update timestamp when we re-use the node, like on media change events */
313 utimensat(AT_FDCWD, devnode, NULL, 0);
318 void udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
320 struct udev *udev = udev_device_get_udev(dev);
321 char filename[UTIL_PATH_SIZE];
322 struct udev_list_entry *list_entry;
324 log_debug("handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d\n",
325 udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid);
327 if (node_fixup(dev, mode, uid, gid) < 0)
330 /* always add /dev/{block,char}/$major:$minor */
331 snprintf(filename, sizeof(filename), TEST_PREFIX "/dev/%s/%u:%u",
332 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
333 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
334 node_symlink(udev, udev_device_get_devnode(dev), filename);
336 /* create/update symlinks, add symlinks to name index */
337 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
338 if (udev_list_entry_get_num(list_entry))
339 /* simple unmanaged link name */
340 node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
342 link_update(dev, udev_list_entry_get_name(list_entry), 1);
346 void udev_node_remove(struct udev_device *dev)
348 struct udev_list_entry *list_entry;
349 char filename[UTIL_PATH_SIZE];
351 /* remove/update symlinks, remove symlinks from name index */
352 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
353 link_update(dev, udev_list_entry_get_name(list_entry), 0);
355 /* remove /dev/{block,char}/$major:$minor */
356 snprintf(filename, sizeof(filename), TEST_PREFIX "/dev/%s/%u:%u",
357 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
358 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));