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);
59 udev_selinux_lsetfilecon(udev, file, mode);
61 info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", file, mode, uid, gid);
63 /* always update timestamp when we re-use the node, like on media change events */
64 utimensat(AT_FDCWD, file, NULL, 0);
66 char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
68 info(udev, "atomically replace existing file '%s'\n", file);
69 util_strscpyl(file_tmp, sizeof(file_tmp), file, TMP_FILE_EXT, NULL);
71 udev_selinux_setfscreatecon(udev, file_tmp, mode);
72 err = mknod(file_tmp, mode, devnum);
73 udev_selinux_resetfscreatecon(udev);
75 err(udev, "mknod '%s' %u:%u %#o failed: %m\n",
76 file_tmp, major(devnum), minor(devnum), mode);
79 err = rename(file_tmp, file);
81 err(udev, "rename '%s' '%s' failed: %m\n", file_tmp, file);
85 info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
87 chown(file, uid, gid);
90 info(udev, "mknod '%s' %u:%u %#o\n", file, major(devnum), minor(devnum), mode);
92 err = util_create_path(udev, file);
93 if (err != 0 && err != -ENOENT)
95 udev_selinux_setfscreatecon(udev, file, mode);
96 err = mknod(file, mode, devnum);
99 udev_selinux_resetfscreatecon(udev);
100 } while (err == -ENOENT);
102 err(udev, "mknod '%s' %u:%u %#o' failed: %m\n", file, major(devnum), minor(devnum), mode);
103 info(udev, "set permissions '%s' %#o uid=%u gid=%u\n", file, mode, uid, gid);
105 chown(file, uid, gid);
111 static int node_symlink(struct udev *udev, const char *node, const char *slink)
114 char target[UTIL_PATH_SIZE];
117 char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
122 /* use relative link */
124 while (node[i] && (node[i] == slink[i])) {
131 while (slink[i] != '\0') {
133 l = util_strpcpy(&s, l, "../");
136 l = util_strscpy(s, l, &node[tail]);
142 /* preserve link with correct target, do not replace node of other device */
143 if (lstat(slink, &stats) == 0) {
144 if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
147 info(udev, "found existing node instead of symlink '%s'\n", slink);
148 if (lstat(node, &stats2) == 0) {
149 if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
150 stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
151 info(udev, "replace device node '%s' with symlink to our node '%s'\n",
154 err(udev, "device node '%s' already exists, "
155 "link to '%s' will not overwrite it\n",
160 } else if (S_ISLNK(stats.st_mode)) {
161 char buf[UTIL_PATH_SIZE];
164 dbg(udev, "found existing symlink '%s'\n", slink);
165 len = readlink(slink, buf, sizeof(buf));
166 if (len > 0 && len < (int)sizeof(buf)) {
168 if (strcmp(target, buf) == 0) {
169 info(udev, "preserve already existing symlink '%s' to '%s'\n",
171 udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
172 utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
178 info(udev, "creating symlink '%s' to '%s'\n", slink, target);
180 err = util_create_path(udev, slink);
181 if (err != 0 && err != -ENOENT)
183 udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
184 err = symlink(target, slink);
187 udev_selinux_resetfscreatecon(udev);
188 } while (err == -ENOENT);
193 info(udev, "atomically replace '%s'\n", slink);
194 util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
197 err = util_create_path(udev, slink_tmp);
198 if (err != 0 && err != -ENOENT)
200 udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
201 err = symlink(target, slink_tmp);
204 udev_selinux_resetfscreatecon(udev);
205 } while (err == -ENOENT);
207 err(udev, "symlink '%s' '%s' failed: %m\n", target, slink_tmp);
210 err = rename(slink_tmp, slink);
212 err(udev, "rename '%s' '%s' failed: %m\n", slink_tmp, slink);
219 /* find device node of device with highest priority */
220 static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
222 struct udev *udev = udev_device_get_udev(dev);
225 const char *target = NULL;
228 priority = udev_device_get_devlink_priority(dev);
229 util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
233 dir = opendir(stackdir);
237 struct udev_device *dev_db;
244 if (dent == NULL || dent->d_name[0] == '\0')
246 if (dent->d_name[0] == '.')
248 if (sscanf(dent->d_name, "%c%i:%i", &type, &maj, &min) != 3)
250 info(udev, "found '%c%i:%i' claiming '%s'\n", type, maj, min, stackdir);
251 devnum = makedev(maj, min);
253 /* did we find ourself? */
254 type2 = strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c';
255 if (udev_device_get_devnum(dev) == devnum && type == type2)
258 dev_db = udev_device_new_from_devnum(udev, type, devnum);
259 if (dev_db != NULL) {
262 devnode = udev_device_get_devnode(dev_db);
263 if (devnode != NULL) {
264 dbg(udev, "compare priority of '%s'(%i) > '%s'(%i)\n", target, priority,
265 udev_device_get_devnode(dev_db), udev_device_get_devlink_priority(dev_db));
266 if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
267 info(udev, "'%s' claims priority %i for '%s'\n",
268 udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
269 priority = udev_device_get_devlink_priority(dev_db);
270 util_strscpy(buf, bufsize, devnode);
274 udev_device_unref(dev_db);
281 /* manage "stack of names" with possibly specified device priorities */
282 static void link_update(struct udev_device *dev, const char *slink, bool add)
284 struct udev *udev = udev_device_get_udev(dev);
285 char name_enc[UTIL_PATH_SIZE];
286 char filename[UTIL_PATH_SIZE * 2];
287 char dirname[UTIL_PATH_SIZE];
289 char buf[UTIL_PATH_SIZE];
291 dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
293 util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
294 snprintf(dirname, sizeof(dirname), "%s/.udev/links/%s", udev_get_dev_path(udev), name_enc);
295 snprintf(filename, sizeof(filename), "%s/%c%u:%u", dirname,
296 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
297 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
300 dbg(udev, "removing index: '%s'\n", filename);
302 util_delete_path(udev, filename);
305 target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
306 if (target == NULL) {
307 info(udev, "no reference left, remove '%s'\n", slink);
309 util_delete_path(udev, slink);
311 info(udev, "creating link '%s' to '%s'\n", slink, target);
312 node_symlink(udev, target, slink);
318 dbg(udev, "creating index: '%s'\n", filename);
322 err = util_create_path(udev, filename);
323 if (err != 0 && err != -ENOENT)
325 fd = open(filename, O_WRONLY|O_CREAT|O_NOFOLLOW, 0444);
330 } while (err == -ENOENT);
334 void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old)
336 struct udev *udev = udev_device_get_udev(dev);
337 struct udev_list_entry *list_entry;
339 /* update possible left-over symlinks */
340 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) {
341 const char *name = udev_list_entry_get_name(list_entry);
342 struct udev_list_entry *list_entry_current;
345 /* check if old link name still belongs to this device */
347 udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
348 const char *name_current = udev_list_entry_get_name(list_entry_current);
350 if (strcmp(name, name_current) == 0) {
358 info(udev, "update old name, '%s' no longer belonging to '%s'\n",
359 name, udev_device_get_devpath(dev));
360 link_update(dev, name, 0);
364 int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
366 struct udev *udev = udev_device_get_udev(dev);
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 /* create/update symlinks, add symlinks to name index */
381 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
382 if (udev_list_entry_get_flags(list_entry))
383 /* simple unmanaged link name */
384 node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
386 link_update(dev, udev_list_entry_get_name(list_entry), 1);
392 int udev_node_remove(struct udev_device *dev)
394 struct udev *udev = udev_device_get_udev(dev);
395 struct udev_list_entry *list_entry;
398 struct udev_device *dev_check;
401 /* remove/update symlinks, remove symlinks from name index */
402 udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
403 link_update(dev, udev_list_entry_get_name(list_entry), 0);
405 devnode = udev_device_get_devnode(dev);
409 if (stat(devnode, &stats) != 0) {
410 info(udev, "device node '%s' not found\n", devnode);
414 if (stats.st_rdev != udev_device_get_devnum(dev)) {
415 info(udev, "device node '%s' points to a different device, skip removal\n", devnode);
420 dev_check = udev_device_new_from_syspath(udev, udev_device_get_syspath(dev));
421 if (dev_check != NULL) {
422 /* do not remove device node if the same sys-device is re-created in the meantime */
423 info(udev, "keeping device node of existing device'%s'\n", devnode);
424 udev_device_unref(dev_check);
428 info(udev, "removing device node '%s'\n", devnode);
429 err = util_unlink_secure(udev, devnode);
430 util_delete_path(udev, devnode);