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 int udev_node_mknod(struct udev_device *dev, const char *file, mode_t mode, uid_t uid, gid_t gid)
38 struct udev *udev = udev_device_get_udev(dev);
39 dev_t devnum = udev_device_get_devnum(dev);
44 if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
50 file = udev_device_get_devnode(dev);
52 if (lstat(file, &stats) == 0) {
53 if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
54 info(udev, "preserve file '%s', because it has correct dev_t\n", file);
55 if (stats.st_mode != mode || stats.st_uid != uid || stats.st_gid != gid) {
56 info(udev, "set permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
58 chown(file, uid, gid);
60 info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
63 * Set initial selinux file context only on add events.
64 * We set the proper context on bootup (triger) or for newly
65 * added devices, but we don't change it later, in case
66 * something else has set a custom context in the meantime.
68 if (strcmp(udev_device_get_action(dev), "add") == 0)
69 udev_selinux_lsetfilecon(udev, file, mode);
70 /* always update timestamp when we re-use the node, like on media change events */
71 utimensat(AT_FDCWD, file, NULL, 0);
73 char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
75 info(udev, "atomically replace existing file '%s'\n", file);
76 util_strscpyl(file_tmp, sizeof(file_tmp), file, TMP_FILE_EXT, NULL);
78 udev_selinux_setfscreatecon(udev, file_tmp, mode);
79 err = mknod(file_tmp, mode, devnum);
80 udev_selinux_resetfscreatecon(udev);
82 err(udev, "mknod '%s' %u:%u %#o failed: %m\n",
83 file_tmp, major(devnum), minor(devnum), mode);
86 err = rename(file_tmp, file);
88 err(udev, "rename '%s' '%s' failed: %m\n", file_tmp, file);
92 info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
94 chown(file, uid, gid);
97 info(udev, "mknod '%s' %u:%u %#o\n", file, major(devnum), minor(devnum), mode);
99 err = util_create_path_selinux(udev, file);
100 if (err != 0 && err != -ENOENT)
102 udev_selinux_setfscreatecon(udev, file, mode);
103 err = mknod(file, mode, devnum);
106 udev_selinux_resetfscreatecon(udev);
107 } while (err == -ENOENT);
109 err(udev, "mknod '%s' %u:%u %#o' failed: %m\n", file, major(devnum), minor(devnum), mode);
110 info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
112 chown(file, uid, gid);
118 static int node_symlink(struct udev *udev, const char *node, const char *slink)
121 char target[UTIL_PATH_SIZE];
124 char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
129 /* use relative link */
131 while (node[i] && (node[i] == slink[i])) {
138 while (slink[i] != '\0') {
140 l = util_strpcpy(&s, l, "../");
143 l = util_strscpy(s, l, &node[tail]);
149 /* preserve link with correct target, do not replace node of other device */
150 if (lstat(slink, &stats) == 0) {
151 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
154 info(udev, "found existing node instead of symlink '%s'\n", slink);
155 if (lstat(node, &stats2) == 0) {
156 if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
157 stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
158 info(udev, "replace device node '%s' with symlink to our node '%s'\n",
161 err(udev, "device node '%s' already exists, "
162 "link to '%s' will not overwrite it\n",
167 } else if (S_ISLNK(stats.st_mode)) {
168 char buf[UTIL_PATH_SIZE];
171 dbg(udev, "found existing symlink '%s'\n", slink);
172 len = readlink(slink, buf, sizeof(buf));
173 if (len > 0 && len < (int)sizeof(buf)) {
175 if (strcmp(target, buf) == 0) {
176 info(udev, "preserve already existing symlink '%s' to '%s'\n",
178 udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
179 utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
185 info(udev, "creating symlink '%s' to '%s'\n", slink, target);
187 err = util_create_path_selinux(udev, slink);
188 if (err != 0 && err != -ENOENT)
190 udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
191 err = symlink(target, slink);
194 udev_selinux_resetfscreatecon(udev);
195 } while (err == -ENOENT);
200 info(udev, "atomically replace '%s'\n", slink);
201 util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
204 err = util_create_path_selinux(udev, slink_tmp);
205 if (err != 0 && err != -ENOENT)
207 udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
208 err = symlink(target, slink_tmp);
211 udev_selinux_resetfscreatecon(udev);
212 } while (err == -ENOENT);
214 err(udev, "symlink '%s' '%s' failed: %m\n", target, slink_tmp);
217 err = rename(slink_tmp, slink);
219 err(udev, "rename '%s' '%s' failed: %m\n", slink_tmp, slink);
226 /* find device node of device with highest priority */
227 static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
229 struct udev *udev = udev_device_get_udev(dev);
232 const char *target = NULL;
235 priority = udev_device_get_devlink_priority(dev);
236 util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
240 dir = opendir(stackdir);
244 struct udev_device *dev_db;
248 if (dent == NULL || dent->d_name[0] == '\0')
250 if (dent->d_name[0] == '.')
253 info(udev, "found '%s' claiming '%s'\n", dent->d_name, stackdir);
255 /* did we find ourself? */
256 if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
259 dev_db = udev_device_new_from_id_filename(udev, dent->d_name);
260 if (dev_db != NULL) {
263 devnode = udev_device_get_devnode(dev_db);
264 if (devnode != NULL) {
265 dbg(udev, "compare priority of '%s'(%i) > '%s'(%i)\n", target, priority,
266 udev_device_get_devnode(dev_db), udev_device_get_devlink_priority(dev_db));
267 if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
268 info(udev, "'%s' claims priority %i for '%s'\n",
269 udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
270 priority = udev_device_get_devlink_priority(dev_db);
271 util_strscpy(buf, bufsize, devnode);
275 udev_device_unref(dev_db);
282 /* manage "stack of names" with possibly specified device priorities */
283 static void link_update(struct udev_device *dev, const char *slink, bool add)
285 struct udev *udev = udev_device_get_udev(dev);
286 char name_enc[UTIL_PATH_SIZE];
287 char filename[UTIL_PATH_SIZE * 2];
288 char dirname[UTIL_PATH_SIZE];
290 char buf[UTIL_PATH_SIZE];
292 dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
294 util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
295 util_strscpyl(dirname, sizeof(dirname), udev_get_run_path(udev), "/links/", name_enc, NULL);
296 util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
299 dbg(udev, "removing index: '%s'\n", filename);
300 if (unlink(filename) == 0)
304 target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
305 if (target == NULL) {
306 info(udev, "no reference left, remove '%s'\n", slink);
307 if (unlink(slink) == 0)
308 util_delete_path(udev, slink);
310 info(udev, "creating link '%s' to '%s'\n", slink, target);
311 node_symlink(udev, target, slink);
317 dbg(udev, "creating index: '%s'\n", filename);
321 err = util_create_path(udev, filename);
322 if (err != 0 && err != -ENOENT)
324 fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
329 } while (err == -ENOENT);
333 void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old)
335 struct udev *udev = udev_device_get_udev(dev);
336 struct udev_list_entry *list_entry;
338 /* update possible left-over symlinks */
339 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) {
340 const char *name = udev_list_entry_get_name(list_entry);
341 struct udev_list_entry *list_entry_current;
344 /* check if old link name still belongs to this device */
346 udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
347 const char *name_current = udev_list_entry_get_name(list_entry_current);
349 if (strcmp(name, name_current) == 0) {
357 info(udev, "update old name, '%s' no longer belonging to '%s'\n",
358 name, udev_device_get_devpath(dev));
359 link_update(dev, name, 0);
363 int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
365 struct udev *udev = udev_device_get_udev(dev);
366 char filename[UTIL_PATH_SIZE];
367 struct udev_list_entry *list_entry;
370 info(udev, "creating device node '%s', devnum=%d:%d, mode=%#o, uid=%d, gid=%d\n",
371 udev_device_get_devnode(dev),
372 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)),
375 if (udev_node_mknod(dev, NULL, mode, uid, gid) != 0) {
380 /* always add /dev/{block,char}/$major:$minor */
381 snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
382 udev_get_dev_path(udev),
383 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
384 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
385 node_symlink(udev, udev_device_get_devnode(dev), filename);
387 /* create/update symlinks, add symlinks to name index */
388 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
389 if (udev_list_entry_get_num(list_entry))
390 /* simple unmanaged link name */
391 node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
393 link_update(dev, udev_list_entry_get_name(list_entry), 1);
399 int udev_node_remove(struct udev_device *dev)
401 struct udev *udev = udev_device_get_udev(dev);
402 struct udev_list_entry *list_entry;
405 struct udev_device *dev_check;
406 char filename[UTIL_PATH_SIZE];
409 /* remove/update symlinks, remove symlinks from name index */
410 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
411 link_update(dev, udev_list_entry_get_name(list_entry), 0);
413 devnode = udev_device_get_devnode(dev);
417 if (stat(devnode, &stats) != 0) {
418 info(udev, "device node '%s' not found\n", devnode);
422 if (stats.st_rdev != udev_device_get_devnum(dev)) {
423 info(udev, "device node '%s' points to a different device, skip removal\n", devnode);
428 dev_check = udev_device_new_from_syspath(udev, udev_device_get_syspath(dev));
429 if (dev_check != NULL) {
430 /* do not remove device node if the same sys-device is re-created in the meantime */
431 info(udev, "keeping device node of existing device'%s'\n", devnode);
432 udev_device_unref(dev_check);
436 info(udev, "removing device node '%s'\n", devnode);
437 err = util_unlink_secure(udev, devnode);
439 util_delete_path(udev, devnode);
441 /* remove /dev/{block,char}/$major:$minor */
442 snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
443 udev_get_dev_path(udev),
444 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
445 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));