2 * libudev - interface to udev device information
4 * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
6 * This program is free software: you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation, either version 2 of the License, or
9 * (at your option) any later version.
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
16 * You should have received a copy of the GNU General Public License
17 * along with this program. If not, see <http://www.gnu.org/licenses/>.
33 #include "libudev-private.h"
38 struct udev_device *parent_device;
44 struct list_head link_list;
45 struct list_head env_list;
52 unsigned long long int seqnum;
53 int num_fake_partitions;
56 struct list_head attr_list;
59 static size_t syspath_to_db_path(struct udev_device *udev_device, char *filename, size_t len)
63 /* translate to location of db file */
64 util_strlcpy(filename, udev_get_dev_path(udev_device->udev), len);
65 start = util_strlcat(filename, "/.udev/db/", len);
66 util_strlcat(filename, udev_device->devpath, len);
67 return util_path_encode(&filename[start], len - start);
70 static int device_read_db(struct udev_device *udev_device)
73 char filename[UTIL_PATH_SIZE];
74 char line[UTIL_LINE_SIZE];
78 syspath_to_db_path(udev_device, filename, sizeof(filename));
80 if (lstat(filename, &stats) != 0) {
81 info(udev_device->udev, "no db file to read %s: %s\n", filename, strerror(errno));
84 if ((stats.st_mode & S_IFMT) == S_IFLNK) {
85 char target[UTIL_PATH_SIZE];
88 info(udev_device->udev, "found a symlink as db file\n");
89 target_len = readlink(filename, target, sizeof(target));
91 target[target_len] = '\0';
93 info(udev_device->udev, "error reading db link %s: %s\n", filename, strerror(errno));
96 dbg(udev_device->udev, "db link points to '%s'\n", target);
97 if (asprintf(&udev_device->devname, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
102 f = fopen(filename, "r");
104 info(udev_device->udev, "error reading db file %s: %s\n", filename, strerror(errno));
107 while (fgets(line, sizeof(line), f)) {
110 unsigned int maj, min;
120 asprintf(&udev_device->devname, "%s/%s", udev_get_dev_path(udev_device->udev), val);
123 sscanf(val, "%u:%u", &maj, &min);
124 device_set_devnum(udev_device, makedev(maj, min));
127 util_strlcpy(filename, udev_get_dev_path(udev_device->udev), sizeof(filename));
128 util_strlcat(filename, "/", sizeof(filename));
129 util_strlcat(filename, val, sizeof(filename));
130 device_add_devlink(udev_device, filename);
133 device_set_devlink_priority(udev_device, atoi(val));
136 device_set_timeout(udev_device, atoi(val));
139 device_set_num_fake_partitions(udev_device, atoi(val));
142 device_set_ignore_remove(udev_device, atoi(val));
145 device_add_property_from_string(udev_device, val);
154 struct udev_device *device_init(struct udev *udev)
156 struct udev_device *udev_device;
161 udev_device = malloc(sizeof(struct udev_device));
162 if (udev_device == NULL)
164 memset(udev_device, 0x00, sizeof(struct udev_device));
165 udev_device->refcount = 1;
166 udev_device->udev = udev;
167 INIT_LIST_HEAD(&udev_device->link_list);
168 INIT_LIST_HEAD(&udev_device->env_list);
169 INIT_LIST_HEAD(&udev_device->attr_list);
170 info(udev_device->udev, "udev_device: %p created\n", udev_device);
175 * udev_device_new_from_syspath:
176 * @udev: udev library context
177 * @syspath: sys device path including sys directory
179 * Create new udev device, and fill in information from the sys
180 * device and the udev database entry. The sypath is the absolute
181 * path to the device, including the sys mount point.
183 * The initial refcount is 1, and needs to be decremented to
184 * release the ressources of the udev device.
186 * Returns: a new udev device, or #NULL, if it does not exist
188 struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
190 char path[UTIL_PATH_SIZE];
192 struct udev_device *udev_device;
199 util_strlcpy(path, syspath, sizeof(path));
200 util_strlcat(path, "/uevent", sizeof(path));
201 if (stat(path, &statbuf) != 0) {
202 info(udev, "not a device :%s\n", syspath);
206 udev_device = device_init(udev);
207 if (udev_device == NULL)
210 /* resolve possible symlink to real path */
211 util_strlcpy(path, syspath, sizeof(path));
212 util_resolve_sys_link(udev, path, sizeof(path));
213 device_set_syspath(udev_device, path);
214 info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
216 if (device_read_db(udev_device) >= 0)
217 info(udev, "device %p filled with udev database data\n", udev_device);
221 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
223 struct udev_device *udev_device_parent = NULL;
224 char path[UTIL_PATH_SIZE];
227 if (udev_device == NULL)
230 util_strlcpy(path, udev_device->syspath, sizeof(path));
232 pos = strrchr(path, '/');
233 if (pos == path || pos == NULL)
236 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
237 if (udev_device_parent != NULL)
238 return udev_device_parent;
241 /* follow "device" link in deprecated sys /sys/class/ layout */
242 if (strncmp(udev_device->devpath, "/class/", 7) == 0) {
243 util_strlcpy(path, udev_device->syspath, sizeof(path));
244 util_strlcat(path, "/device", sizeof(path));
245 if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0) {
246 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
247 if (udev_device_parent != NULL)
248 return udev_device_parent;
254 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
256 if (udev_device->parent_device != NULL) {
257 info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
258 return udev_device->parent_device;
260 udev_device->parent_device = device_new_from_parent(udev_device);
261 return udev_device->parent_device;
265 * udev_device_get_udev:
266 * @udev_device: udev device
268 * Retrieve the udev library context the device was created with.
270 * Returns: the udev library context
272 struct udev *udev_device_get_udev(struct udev_device *udev_device)
274 if (udev_device == NULL)
276 return udev_device->udev;
281 * @udev_device: udev device
283 * Take a reference of a udev device.
285 * Returns: the passed udev device
287 struct udev_device *udev_device_ref(struct udev_device *udev_device)
289 if (udev_device == NULL)
291 udev_device->refcount++;
297 * @udev_device: udev device
299 * Drop a reference of a udev device. If the refcount reaches zero,
300 * the ressources of the device will be released.
303 void udev_device_unref(struct udev_device *udev_device)
305 if (udev_device == NULL)
307 udev_device->refcount--;
308 if (udev_device->refcount > 0)
310 if (udev_device->parent_device != NULL)
311 udev_device_unref(udev_device->parent_device);
312 free(udev_device->syspath);
313 free(udev_device->devname);
314 free(udev_device->subsystem);
315 util_name_list_cleanup(udev_device->udev, &udev_device->link_list);
316 util_name_list_cleanup(udev_device->udev, &udev_device->env_list);
317 free(udev_device->action);
318 free(udev_device->driver);
319 free(udev_device->devpath_old);
320 free(udev_device->physdevpath);
321 util_name_list_cleanup(udev_device->udev, &udev_device->attr_list);
322 info(udev_device->udev, "udev_device: %p released\n", udev_device);
327 * udev_device_get_devpath:
328 * @udev_device: udev device
330 * Retrieve the kernel devpath value of the udev device. The path
331 * does not contain the sys mount point, and starts with a '/'.
333 * Returns: the devpath of the udev device
335 const char *udev_device_get_devpath(struct udev_device *udev_device)
337 if (udev_device == NULL)
339 return udev_device->devpath;
343 * udev_device_get_syspath:
344 * @udev_device: udev device
346 * Retrieve the sys path of the udev device. The path is an
347 * absolute path and starts with the sys mount point.
349 * Returns: the sys path of the udev device
351 const char *udev_device_get_syspath(struct udev_device *udev_device)
353 if (udev_device == NULL)
355 return udev_device->syspath;
358 const char *udev_device_get_sysname(struct udev_device *udev_device)
360 if (udev_device == NULL)
362 return udev_device->sysname;
366 * udev_device_get_devname:
367 * @udev_device: udev device
369 * Retrieve the device node file name belonging to the udev device.
370 * The path is an absolute path, and starts with the device directory.
372 * Returns: the device node file name of the udev device, or #NULL if no device node exists
374 const char *udev_device_get_devname(struct udev_device *udev_device)
376 if (udev_device == NULL)
378 return udev_device->devname;
382 * udev_device_get_subsystem:
383 * @udev_device: udev device
385 * Retrieve the subsystem string of the udev device. The string does not
388 * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
390 const char *udev_device_get_subsystem(struct udev_device *udev_device)
392 char subsystem[UTIL_NAME_SIZE];
394 if (udev_device == NULL)
396 if (udev_device->subsystem != NULL)
397 return udev_device->subsystem;
399 /* read "subsytem" link */
400 if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
401 udev_device->subsystem = strdup(subsystem);
402 return udev_device->subsystem;
406 if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
407 udev_device->subsystem = strdup("module");
408 return udev_device->subsystem;
410 if (strstr(udev_device->devpath, "/drivers/") != NULL) {
411 udev_device->subsystem = strdup("drivers");
412 return udev_device->subsystem;
414 if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
415 strncmp(udev_device->devpath, "/class/", 7) == 0 ||
416 strncmp(udev_device->devpath, "/bus/", 5) == 0) {
417 udev_device->subsystem = strdup("subsystem");
418 return udev_device->subsystem;
424 * udev_device_get_devlinks:
425 * @udev_device: udev device
426 * @cb: function to be called for every device link found
427 * @data: data to be passed to the function
429 * Retrieve the device links pointing to the device file of the
430 * udev device. For every device link, the passed function will be
431 * called with the device link string.
432 * The path is an absolute path, and starts with the device directory.
433 * If the function returns 1, remaning device links will be ignored.
435 * Returns: the number of device links passed to the caller, or a negative value on error
437 int udev_device_get_devlinks(struct udev_device *udev_device,
438 int (*cb)(struct udev_device *udev_device, const char *value, void *data),
441 struct util_name_entry *name_loop;
444 if (udev_device == NULL)
446 list_for_each_entry(name_loop, &udev_device->link_list, node) {
448 if (cb(udev_device, name_loop->name, data) != 0)
455 * udev_device_get_properties:
456 * @udev_device: udev device
457 * @cb: function to be called for every property found
458 * @data: data to be passed to the function
460 * Retrieve the property key/value pairs belonging to the
461 * udev device. For every key/value pair, the passed function will be
462 * called. If the function returns 1, remaning properties will be
465 * Returns: the number of properties passed to the caller, or a negative value on error
467 int udev_device_get_properties(struct udev_device *udev_device,
468 int (*cb)(struct udev_device *udev_device, const char *key, const char *value, void *data),
471 struct util_name_entry *name_loop;
474 if (udev_device == NULL)
476 list_for_each_entry(name_loop, &udev_device->env_list, node) {
478 if (cb(udev_device, name_loop->name, name_loop->value, data) != 0)
484 const char *udev_device_get_driver(struct udev_device *udev_device)
486 char driver[UTIL_NAME_SIZE];
488 if (udev_device == NULL)
490 if (udev_device->driver != NULL)
491 return udev_device->driver;
492 if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
494 udev_device->driver = strdup(driver);
495 return udev_device->driver;
498 dev_t udev_device_get_devnum(struct udev_device *udev_device)
500 if (udev_device == NULL)
501 return makedev(0, 0);
502 return udev_device->devnum;
505 const char *udev_device_get_action(struct udev_device *udev_device)
507 if (udev_device == NULL)
509 return udev_device->action;
512 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
514 if (udev_device == NULL)
516 return udev_device->seqnum;
519 const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
521 struct util_name_entry *name_loop;
522 char path[UTIL_PATH_SIZE];
523 char value[UTIL_NAME_SIZE];
527 const char *val = NULL;
529 /* look for possibly already cached result */
530 list_for_each_entry(name_loop, &udev_device->attr_list, node) {
531 if (strcmp(name_loop->name, attr) == 0) {
532 info(udev_device->udev, "'%s' in cache '%s'\n", attr, name_loop->value);
533 return name_loop->value;
537 util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
538 util_strlcat(path, "/", sizeof(path));
539 util_strlcat(path, attr, sizeof(path));
541 if (lstat(path, &statbuf) != 0) {
542 info(udev_device->udev, "stat '%s' failed: %s\n", path, strerror(errno));
546 if (S_ISLNK(statbuf.st_mode)) {
547 /* links return the last element of the target path */
548 char target[UTIL_NAME_SIZE];
552 len = readlink(path, target, sizeof(target));
555 pos = strrchr(target, '/');
558 info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
559 val = util_name_list_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0)->value;
565 /* skip directories */
566 if (S_ISDIR(statbuf.st_mode))
569 /* skip non-readable files */
570 if ((statbuf.st_mode & S_IRUSR) == 0)
573 /* read attribute value */
574 fd = open(path, O_RDONLY);
576 info(udev_device->udev, "attribute '%s' can not be opened\n", path);
579 size = read(fd, value, sizeof(value));
583 if (size == sizeof(value))
586 /* got a valid value, store it in cache and return it */
588 util_remove_trailing_chars(value, '\n');
589 info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
590 val = util_name_list_add(udev_device->udev, &udev_device->attr_list, attr, value, 0)->value;
594 int device_set_syspath(struct udev_device *udev_device, const char *syspath)
598 udev_device->syspath = strdup(syspath);
599 if (udev_device->syspath == NULL)
601 udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
602 pos = strrchr(udev_device->syspath, '/');
605 udev_device->sysname = &pos[1];
609 int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
611 udev_device->subsystem = strdup(subsystem);
612 if (udev_device->subsystem == NULL)
617 int device_set_devname(struct udev_device *udev_device, const char *devname)
619 udev_device->devname = strdup(devname);
620 if (udev_device->devname == NULL)
625 int device_add_devlink(struct udev_device *udev_device, const char *devlink)
627 if (util_name_list_add(udev_device->udev, &udev_device->link_list, devlink, NULL, 0) == NULL)
632 int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
634 if (util_name_list_add(udev_device->udev, &udev_device->env_list, key, value, 0) == NULL)
639 int device_add_property_from_string(struct udev_device *udev_device, const char *property)
641 char name[UTIL_PATH_SIZE];
644 strncpy(name, property, sizeof(name));
645 val = strchr(name, '=');
652 device_add_property(udev_device, name, val);
656 int device_set_action(struct udev_device *udev_device, const char *action)
658 udev_device->action = strdup(action);
659 if (udev_device->action == NULL)
664 int device_set_driver(struct udev_device *udev_device, const char *driver)
666 udev_device->driver = strdup(driver);
667 if (udev_device->driver == NULL)
672 const char *device_get_devpath_old(struct udev_device *udev_device)
674 if (udev_device == NULL)
676 return udev_device->devpath_old;
679 int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
681 udev_device->devpath_old = strdup(devpath_old);
682 if (udev_device->devpath_old == NULL)
687 const char *device_get_physdevpath(struct udev_device *udev_device)
689 if (udev_device == NULL)
691 return udev_device->physdevpath;
694 int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
696 udev_device->physdevpath = strdup(physdevpath);
697 if (udev_device->physdevpath == NULL)
702 int device_get_timeout(struct udev_device *udev_device)
704 if (udev_device == NULL)
706 return udev_device->timeout;
709 int device_set_timeout(struct udev_device *udev_device, int timeout)
711 udev_device->timeout = timeout;
715 int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
717 udev_device->seqnum = seqnum;
721 int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
723 udev_device->devnum = devnum;
727 int device_get_num_fake_partitions(struct udev_device *udev_device)
729 if (udev_device == NULL)
731 return udev_device->num_fake_partitions;
734 int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
736 udev_device->num_fake_partitions = num;
740 int device_get_devlink_priority(struct udev_device *udev_device)
742 if (udev_device == NULL)
744 return udev_device->devlink_priority;
747 int device_set_devlink_priority(struct udev_device *udev_device, int prio)
749 udev_device->devlink_priority = prio;
753 int device_get_ignore_remove(struct udev_device *udev_device)
755 if (udev_device == NULL)
757 return udev_device->ignore_remove;
760 int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
762 udev_device->ignore_remove = ignore;