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/>.
31 #include "libudev-private.h"
36 struct udev_device *parent_device;
42 struct list_node devlink_list;
43 struct list_node properties_list;
51 unsigned long long int seqnum;
52 int num_fake_partitions;
55 struct list_node 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];
77 syspath_to_db_path(udev_device, filename, sizeof(filename));
79 if (lstat(filename, &stats) != 0) {
80 info(udev_device->udev, "no db file to read %s: %s\n", filename, strerror(errno));
83 if ((stats.st_mode & S_IFMT) == S_IFLNK) {
84 char target[UTIL_PATH_SIZE];
87 target_len = readlink(filename, target, sizeof(target));
89 target[target_len] = '\0';
91 info(udev_device->udev, "error reading db link %s: %s\n", filename, strerror(errno));
94 if (asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
96 info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
100 f = fopen(filename, "r");
102 info(udev_device->udev, "error reading db file %s: %s\n", filename, strerror(errno));
105 while (fgets(line, sizeof(line), f)) {
117 asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), val);
120 util_strlcpy(filename, udev_get_dev_path(udev_device->udev), sizeof(filename));
121 util_strlcat(filename, "/", sizeof(filename));
122 util_strlcat(filename, val, sizeof(filename));
123 device_add_devlink(udev_device, filename);
126 device_set_devlink_priority(udev_device, atoi(val));
129 device_set_event_timeout(udev_device, atoi(val));
132 device_set_num_fake_partitions(udev_device, atoi(val));
135 device_set_ignore_remove(udev_device, atoi(val));
138 device_add_property_from_string(udev_device, val);
144 info(udev_device->udev, "device %p filled with db file data\n", udev_device);
148 static int device_read_uevent_file(struct udev_device *udev_device)
150 char filename[UTIL_PATH_SIZE];
152 char line[UTIL_LINE_SIZE];
156 util_strlcpy(filename, udev_device->syspath, sizeof(filename));
157 util_strlcat(filename, "/uevent", sizeof(filename));
158 f = fopen(filename, "r");
162 while (fgets(line, sizeof(line), f)) {
165 pos = strchr(line, '\n');
170 if (strncmp(line, "MAJOR=", 6) == 0)
171 maj = strtoull(&line[6], NULL, 10);
172 else if (strncmp(line, "MINOR=", 6) == 0)
173 min = strtoull(&line[6], NULL, 10);
175 device_add_property_from_string(udev_device, line);
178 udev_device->devnum = makedev(maj, min);
184 static void device_load_info(struct udev_device *device)
186 device_read_uevent_file(device);
187 device_read_db(device);
188 device->info_loaded = 1;
191 void device_set_info_loaded(struct udev_device *device)
193 device->info_loaded = 1;
196 struct udev_device *device_init(struct udev *udev)
198 struct udev_device *udev_device;
203 udev_device = malloc(sizeof(struct udev_device));
204 if (udev_device == NULL)
206 memset(udev_device, 0x00, sizeof(struct udev_device));
207 udev_device->refcount = 1;
208 udev_device->udev = udev;
209 list_init(&udev_device->devlink_list);
210 list_init(&udev_device->properties_list);
211 list_init(&udev_device->attr_list);
212 info(udev_device->udev, "udev_device: %p created\n", udev_device);
217 * udev_device_new_from_syspath:
218 * @udev: udev library context
219 * @syspath: sys device path including sys directory
221 * Create new udev device, and fill in information from the sys
222 * device and the udev database entry. The sypath is the absolute
223 * path to the device, including the sys mount point.
225 * The initial refcount is 1, and needs to be decremented to
226 * release the ressources of the udev device.
228 * Returns: a new udev device, or #NULL, if it does not exist
230 struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
235 char path[UTIL_PATH_SIZE];
237 struct udev_device *udev_device;
244 /* path starts in sys */
245 len = strlen(udev_get_sys_path(udev));
246 if (strncmp(syspath, udev_get_sys_path(udev), len) != 0) {
247 info(udev, "not in sys :%s\n", syspath);
251 /* path is not a root directory */
252 subdir = &syspath[len+1];
253 pos = strrchr(subdir, '/');
254 if (pos == NULL || pos < &subdir[2]) {
255 info(udev, "not a subdir :%s\n", syspath);
259 /* resolve possible symlink to real path */
260 util_strlcpy(path, syspath, sizeof(path));
261 util_resolve_sys_link(udev, path, sizeof(path));
263 /* path exists in sys */
264 if (strncmp(&syspath[len], "/devices/", 9) == 0 ||
265 strncmp(&syspath[len], "/class/", 7) == 0 ||
266 strncmp(&syspath[len], "/block/", 7) == 0) {
267 char file[UTIL_PATH_SIZE];
269 /* all "devices" require a "uevent" file */
270 util_strlcpy(file, path, sizeof(file));
271 util_strlcat(file, "/uevent", sizeof(file));
272 if (stat(file, &statbuf) != 0) {
273 info(udev, "not a device: %s\n", syspath);
277 /* everything else just needs to be a directory */
278 if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode)) {
279 info(udev, "directory not found: %s\n", syspath);
284 udev_device = device_init(udev);
285 if (udev_device == NULL)
288 device_set_syspath(udev_device, path);
289 info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
294 struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
296 char path[UTIL_PATH_SIZE];
297 const char *type_str;
298 struct udev_enumerate *udev_enumerate;
299 struct udev_list_entry *list_entry;
300 struct udev_device *device = NULL;
304 else if (type == 'c')
309 /* /sys/dev/{block,char}/<maj>:<min> link */
310 snprintf(path, sizeof(path), "%s/dev/%s/%u:%u", udev_get_sys_path(udev),
311 type_str, major(devnum), minor(devnum));
312 if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
313 return udev_device_new_from_syspath(udev, path);
315 udev_enumerate = udev_enumerate_new(udev);
316 if (udev_enumerate == NULL)
319 /* fallback to search sys devices for the major/minor */
321 udev_enumerate_scan_devices(udev_enumerate, "block", NULL);
322 else if (type == 'c')
323 udev_enumerate_scan_devices(udev_enumerate, "!block", NULL);
324 udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
325 struct udev_device *device_loop;
327 device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
328 if (device_loop != NULL) {
329 if (udev_device_get_devnum(device_loop) == devnum) {
330 const char *subsystem;
332 subsystem = udev_device_get_subsystem(device_loop);
333 if (type == 'b' && strcmp(subsystem, "block") != 0)
335 if (type == 'c' && strcmp(subsystem, "block") == 0)
337 device = device_loop;
340 udev_device_unref(device_loop);
343 udev_enumerate_unref(udev_enumerate);
347 static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
349 struct udev_device *udev_device_parent = NULL;
350 char path[UTIL_PATH_SIZE];
353 /* follow "device" link in deprecated sys layout */
354 if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
355 strncmp(udev_device->devpath, "/block/", 7) == 0) {
356 util_strlcpy(path, udev_device->syspath, sizeof(path));
357 util_strlcat(path, "/device", sizeof(path));
358 if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0)
359 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
360 return udev_device_parent;
363 util_strlcpy(path, udev_device->syspath, sizeof(path));
364 subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
368 pos = strrchr(subdir, '/');
369 if (pos == NULL || pos < &subdir[2])
372 udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
373 if (udev_device_parent != NULL)
374 return udev_device_parent;
379 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
381 if (udev_device == NULL)
384 if (udev_device->parent_device != NULL) {
385 info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
386 return udev_device->parent_device;
388 udev_device->parent_device = device_new_from_parent(udev_device);
389 return udev_device->parent_device;
393 * udev_device_get_udev:
394 * @udev_device: udev device
396 * Retrieve the udev library context the device was created with.
398 * Returns: the udev library context
400 struct udev *udev_device_get_udev(struct udev_device *udev_device)
402 if (udev_device == NULL)
404 return udev_device->udev;
409 * @udev_device: udev device
411 * Take a reference of a udev device.
413 * Returns: the passed udev device
415 struct udev_device *udev_device_ref(struct udev_device *udev_device)
417 if (udev_device == NULL)
419 udev_device->refcount++;
425 * @udev_device: udev device
427 * Drop a reference of a udev device. If the refcount reaches zero,
428 * the ressources of the device will be released.
431 void udev_device_unref(struct udev_device *udev_device)
433 if (udev_device == NULL)
435 udev_device->refcount--;
436 if (udev_device->refcount > 0)
438 if (udev_device->parent_device != NULL)
439 udev_device_unref(udev_device->parent_device);
440 free(udev_device->syspath);
441 free(udev_device->devnode);
442 free(udev_device->subsystem);
443 list_cleanup(udev_device->udev, &udev_device->devlink_list);
444 list_cleanup(udev_device->udev, &udev_device->properties_list);
445 free(udev_device->action);
446 free(udev_device->driver);
447 free(udev_device->devpath_old);
448 free(udev_device->physdevpath);
449 list_cleanup(udev_device->udev, &udev_device->attr_list);
450 info(udev_device->udev, "udev_device: %p released\n", udev_device);
455 * udev_device_get_devpath:
456 * @udev_device: udev device
458 * Retrieve the kernel devpath value of the udev device. The path
459 * does not contain the sys mount point, and starts with a '/'.
461 * Returns: the devpath of the udev device
463 const char *udev_device_get_devpath(struct udev_device *udev_device)
465 if (udev_device == NULL)
467 return udev_device->devpath;
471 * udev_device_get_syspath:
472 * @udev_device: udev device
474 * Retrieve the sys path of the udev device. The path is an
475 * absolute path and starts with the sys mount point.
477 * Returns: the sys path of the udev device
479 const char *udev_device_get_syspath(struct udev_device *udev_device)
481 if (udev_device == NULL)
483 return udev_device->syspath;
486 const char *udev_device_get_sysname(struct udev_device *udev_device)
488 if (udev_device == NULL)
490 return udev_device->sysname;
494 * udev_device_get_devnode:
495 * @udev_device: udev device
497 * Retrieve the device node file name belonging to the udev device.
498 * The path is an absolute path, and starts with the device directory.
500 * Returns: the device node file name of the udev device, or #NULL if no device node exists
502 const char *udev_device_get_devnode(struct udev_device *udev_device)
504 if (udev_device == NULL)
506 if (!udev_device->info_loaded)
507 device_load_info(udev_device);
508 return udev_device->devnode;
512 * udev_device_get_subsystem:
513 * @udev_device: udev device
515 * Retrieve the subsystem string of the udev device. The string does not
518 * Returns: the subsystem name of the udev device, or #NULL if it can not be determined
520 const char *udev_device_get_subsystem(struct udev_device *udev_device)
522 char subsystem[UTIL_NAME_SIZE];
524 if (udev_device == NULL)
526 if (udev_device->subsystem != NULL)
527 return udev_device->subsystem;
529 /* read "subsytem" link */
530 if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
531 udev_device->subsystem = strdup(subsystem);
532 return udev_device->subsystem;
536 if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
537 udev_device->subsystem = strdup("module");
538 return udev_device->subsystem;
540 if (strstr(udev_device->devpath, "/drivers/") != NULL) {
541 udev_device->subsystem = strdup("drivers");
542 return udev_device->subsystem;
544 if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
545 strncmp(udev_device->devpath, "/class/", 7) == 0 ||
546 strncmp(udev_device->devpath, "/bus/", 5) == 0) {
547 udev_device->subsystem = strdup("subsystem");
548 return udev_device->subsystem;
554 * udev_device_get_devlinks_list_entry:
555 * @udev_device: udev device
557 * Retrieve the list of device links pointing to the device file of
558 * the udev device. The next list entry can be retrieved with
559 * udev_list_entry_next(), which returns #NULL if no more entries exist.
560 * The devlink path can be retrieved from the list entry by
561 * udev_list_entry_get_name(). The path is an absolute path, and starts with
562 * the device directory.
564 * Returns: the first entry of the device node link list
566 struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
568 if (udev_device == NULL)
570 if (!udev_device->info_loaded)
571 device_load_info(udev_device);
572 return list_get_entry(&udev_device->devlink_list);
576 * udev_device_get_properties_list_entry:
577 * @udev_device: udev device
579 * Retrieve the list of key/value device properties of the udev
580 * device. The next list entry can be retrieved with udev_list_entry_next(),
581 * which returns #NULL if no more entries exist. The property name
582 * can be retrieved from the list entry by udev_list_get_name(),
583 * the property value by udev_list_get_value().
585 * Returns: the first entry of the property list
587 struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
589 if (udev_device == NULL)
591 if (!udev_device->info_loaded)
592 device_load_info(udev_device);
593 return list_get_entry(&udev_device->properties_list);
596 const char *udev_device_get_driver(struct udev_device *udev_device)
598 char driver[UTIL_NAME_SIZE];
600 if (udev_device == NULL)
602 if (udev_device->driver != NULL)
603 return udev_device->driver;
604 if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
606 udev_device->driver = strdup(driver);
607 return udev_device->driver;
610 dev_t udev_device_get_devnum(struct udev_device *udev_device)
612 if (udev_device == NULL)
613 return makedev(0, 0);
614 if (!udev_device->info_loaded)
615 device_load_info(udev_device);
616 return udev_device->devnum;
619 const char *udev_device_get_action(struct udev_device *udev_device)
621 if (udev_device == NULL)
623 return udev_device->action;
626 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
628 if (udev_device == NULL)
630 return udev_device->seqnum;
633 const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
635 struct udev_list_entry *list_entry;
636 char path[UTIL_PATH_SIZE];
637 char value[UTIL_NAME_SIZE];
641 const char *val = NULL;
643 /* look for possibly already cached result */
644 udev_list_entry_foreach(list_entry, list_get_entry(&udev_device->attr_list)) {
645 if (strcmp(udev_list_entry_get_name(list_entry), attr) == 0) {
646 info(udev_device->udev, "got '%s' (%s) from cache\n", attr, udev_list_entry_get_value(list_entry));
647 return udev_list_entry_get_value(list_entry);
651 util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
652 util_strlcat(path, "/", sizeof(path));
653 util_strlcat(path, attr, sizeof(path));
655 if (lstat(path, &statbuf) != 0) {
656 info(udev_device->udev, "stat '%s' failed: %s\n", path, strerror(errno));
660 if (S_ISLNK(statbuf.st_mode)) {
661 /* links return the last element of the target path */
662 char target[UTIL_NAME_SIZE];
666 len = readlink(path, target, sizeof(target));
669 pos = strrchr(target, '/');
672 info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
673 list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0, 0);
674 val = udev_list_entry_get_value(list_entry);
680 /* skip directories */
681 if (S_ISDIR(statbuf.st_mode))
684 /* skip non-readable files */
685 if ((statbuf.st_mode & S_IRUSR) == 0)
688 /* read attribute value */
689 fd = open(path, O_RDONLY);
691 info(udev_device->udev, "attribute '%s' can not be opened\n", path);
694 size = read(fd, value, sizeof(value));
698 if (size == sizeof(value))
701 /* got a valid value, store it in cache and return it */
703 util_remove_trailing_chars(value, '\n');
704 info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
705 list_entry = list_entry_add(udev_device->udev, &udev_device->attr_list, attr, value, 0, 0);
706 val = udev_list_entry_get_value(list_entry);
710 int device_set_syspath(struct udev_device *udev_device, const char *syspath)
714 udev_device->syspath = strdup(syspath);
715 if (udev_device->syspath == NULL)
717 udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
718 pos = strrchr(udev_device->syspath, '/');
721 udev_device->sysname = &pos[1];
725 int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
727 udev_device->subsystem = strdup(subsystem);
728 if (udev_device->subsystem == NULL)
733 int device_set_devnode(struct udev_device *udev_device, const char *devnode)
735 udev_device->devnode = strdup(devnode);
736 if (udev_device->devnode == NULL)
741 int device_add_devlink(struct udev_device *udev_device, const char *devlink)
743 if (list_entry_add(udev_device->udev, &udev_device->devlink_list, devlink, NULL, 1, 0) == NULL)
748 int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
750 if (list_entry_add(udev_device->udev, &udev_device->properties_list, key, value, 1, 0) == NULL)
755 int device_add_property_from_string(struct udev_device *udev_device, const char *property)
757 char name[UTIL_PATH_SIZE];
760 strncpy(name, property, sizeof(name));
761 val = strchr(name, '=');
768 device_add_property(udev_device, name, val);
772 int device_set_action(struct udev_device *udev_device, const char *action)
774 udev_device->action = strdup(action);
775 if (udev_device->action == NULL)
780 int device_set_driver(struct udev_device *udev_device, const char *driver)
782 udev_device->driver = strdup(driver);
783 if (udev_device->driver == NULL)
788 const char *device_get_devpath_old(struct udev_device *udev_device)
790 return udev_device->devpath_old;
793 int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
795 udev_device->devpath_old = strdup(devpath_old);
796 if (udev_device->devpath_old == NULL)
801 const char *device_get_physdevpath(struct udev_device *udev_device)
803 return udev_device->physdevpath;
806 int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
808 udev_device->physdevpath = strdup(physdevpath);
809 if (udev_device->physdevpath == NULL)
814 int device_get_timeout(struct udev_device *udev_device)
816 return udev_device->timeout;
819 int device_set_timeout(struct udev_device *udev_device, int timeout)
821 udev_device->timeout = timeout;
824 int device_get_event_timeout(struct udev_device *udev_device)
826 if (!udev_device->info_loaded)
827 device_load_info(udev_device);
828 return udev_device->event_timeout;
831 int device_set_event_timeout(struct udev_device *udev_device, int event_timeout)
833 udev_device->event_timeout = event_timeout;
837 int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
839 udev_device->seqnum = seqnum;
843 int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
845 udev_device->devnum = devnum;
849 int device_get_num_fake_partitions(struct udev_device *udev_device)
851 if (!udev_device->info_loaded)
852 device_load_info(udev_device);
853 return udev_device->num_fake_partitions;
856 int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
858 udev_device->num_fake_partitions = num;
862 int device_get_devlink_priority(struct udev_device *udev_device)
864 if (!udev_device->info_loaded)
865 device_load_info(udev_device);
866 return udev_device->devlink_priority;
869 int device_set_devlink_priority(struct udev_device *udev_device, int prio)
871 udev_device->devlink_priority = prio;
875 int device_get_ignore_remove(struct udev_device *udev_device)
877 if (!udev_device->info_loaded)
878 device_load_info(udev_device);
879 return udev_device->ignore_remove;
882 int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
884 udev_device->ignore_remove = ignore;