2 * libudev - interface to udev device information
4 * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
6 * This library is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
22 #include <sys/param.h>
25 #include "libudev-private.h"
28 * SECTION:libudev-enumerate
29 * @short_description: lookup and sort sys devices
31 * Lookup devices in the sys filesystem, filter devices by properties,
32 * and return a sorted list of devices.
43 * Opaque object representing one device lookup/sort context.
45 struct udev_enumerate {
48 struct udev_list_node sysattr_match_list;
49 struct udev_list_node sysattr_nomatch_list;
50 struct udev_list_node subsystem_match_list;
51 struct udev_list_node subsystem_nomatch_list;
52 struct udev_list_node sysname_match_list;
53 struct udev_list_node properties_match_list;
54 struct udev_list_node tags_match_list;
55 struct udev_list_node devices_list;
56 struct syspath *devices;
57 unsigned int devices_cur;
58 unsigned int devices_max;
59 bool devices_uptodate:1;
60 bool match_is_initialized;
65 * @udev: udev library context
67 * Returns: an enumeration context
69 struct udev_enumerate *udev_enumerate_new(struct udev *udev)
71 struct udev_enumerate *udev_enumerate;
73 udev_enumerate = calloc(1, sizeof(struct udev_enumerate));
74 if (udev_enumerate == NULL)
76 udev_enumerate->refcount = 1;
77 udev_enumerate->udev = udev;
78 udev_list_init(&udev_enumerate->sysattr_match_list);
79 udev_list_init(&udev_enumerate->sysattr_nomatch_list);
80 udev_list_init(&udev_enumerate->subsystem_match_list);
81 udev_list_init(&udev_enumerate->subsystem_nomatch_list);
82 udev_list_init(&udev_enumerate->sysname_match_list);
83 udev_list_init(&udev_enumerate->properties_match_list);
84 udev_list_init(&udev_enumerate->tags_match_list);
85 udev_list_init(&udev_enumerate->devices_list);
86 return udev_enumerate;
91 * @udev_enumerate: context
93 * Take a reference of a enumeration context.
95 * Returns: the passed enumeration context
97 struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
99 if (udev_enumerate == NULL)
101 udev_enumerate->refcount++;
102 return udev_enumerate;
106 * udev_enumerate_unref:
107 * @udev_enumerate: context
109 * Drop a reference of an enumeration context. If the refcount reaches zero,
110 * all resources of the enumeration context will be released.
112 void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
116 if (udev_enumerate == NULL)
118 udev_enumerate->refcount--;
119 if (udev_enumerate->refcount > 0)
121 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_match_list);
122 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_nomatch_list);
123 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_match_list);
124 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_nomatch_list);
125 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysname_match_list);
126 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->properties_match_list);
127 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->tags_match_list);
128 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
129 for (i = 0; i < udev_enumerate->devices_cur; i++)
130 free(udev_enumerate->devices[i].syspath);
131 free(udev_enumerate->devices);
132 free(udev_enumerate);
136 * udev_enumerate_get_udev:
137 * @udev_enumerate: context
139 * Returns: the udev library context.
141 struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
143 if (udev_enumerate == NULL)
145 return udev_enumerate->udev;
148 static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath)
151 struct syspath *entry;
153 /* double array size if needed */
154 if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) {
158 add = udev_enumerate->devices_max;
161 buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath));
164 udev_enumerate->devices = buf;
165 udev_enumerate->devices_max += add;
168 path = strdup(syspath);
171 entry = &udev_enumerate->devices[udev_enumerate->devices_cur];
172 entry->syspath = path;
173 entry->len = strlen(path);
174 udev_enumerate->devices_cur++;
175 udev_enumerate->devices_uptodate = false;
179 static int syspath_cmp(const void *p1, const void *p2)
181 const struct syspath *path1 = p1;
182 const struct syspath *path2 = p2;
186 len = MIN(path1->len, path2->len);
187 ret = memcmp(path1->syspath, path2->syspath, len);
189 if (path1->len < path2->len)
191 else if (path1->len > path2->len)
197 /* For devices that should be moved to the absolute end of the list */
198 static bool devices_delay_end(struct udev *udev, const char *syspath)
200 static const char *delay_device_list[] = {
208 len = strlen(udev_get_sys_path(udev));
209 for (i = 0; delay_device_list[i] != NULL; i++) {
210 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
211 dbg(udev, "delaying: %s\n", syspath);
218 /* For devices that should just be moved a little bit later, just
219 * before the point where some common path prefix changes. Returns the
220 * number of characters that make up that common prefix */
221 static size_t devices_delay_later(struct udev *udev, const char *syspath)
225 /* For sound cards the control device must be enumerated last
226 * to make sure it's the final device node that gets ACLs
227 * applied. Applications rely on this fact and use ACL changes
228 * on the control node as an indicator that the ACL change of
229 * the entire sound card completed. The kernel makes this
230 * guarantee when creating those devices, and hence we should
231 * too when enumerating them. */
233 if ((c = strstr(syspath, "/sound/card"))) {
235 c += strcspn(c, "/");
237 if (strncmp(c, "/controlC", 9) == 0)
238 return c - syspath + 1;
245 * udev_enumerate_get_list_entry:
246 * @udev_enumerate: context
248 * Returns: the first entry of the sorted list of device paths.
250 struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
252 if (udev_enumerate == NULL)
254 if (!udev_enumerate->devices_uptodate) {
257 struct syspath *prev = NULL, *move_later = NULL;
258 size_t move_later_prefix = 0;
260 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
261 qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
263 max = udev_enumerate->devices_cur;
264 for (i = 0; i < max; i++) {
265 struct syspath *entry = &udev_enumerate->devices[i];
267 /* skip duplicated entries */
269 entry->len == prev->len &&
270 memcmp(entry->syspath, prev->syspath, entry->len) == 0)
274 /* skip to be delayed devices, and add them to the end of the list */
275 if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
276 syspath_add(udev_enumerate, entry->syspath);
280 /* skip to be delayed devices, and move the to
281 * the point where the prefix changes. We can
282 * only move one item at a time. */
284 move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
286 if (move_later_prefix > 0) {
293 strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) {
295 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
296 move_later->syspath, NULL, 0, 0);
300 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
301 entry->syspath, NULL, 0, 0);
305 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
306 move_later->syspath, NULL, 0, 0);
308 /* add and cleanup delayed devices from end of list */
309 for (i = max; i < udev_enumerate->devices_cur; i++) {
310 struct syspath *entry = &udev_enumerate->devices[i];
312 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
313 entry->syspath, NULL, 0, 0);
314 free(entry->syspath);
316 udev_enumerate->devices_cur = max;
318 udev_enumerate->devices_uptodate = true;
320 return udev_list_get_entry(&udev_enumerate->devices_list);
324 * udev_enumerate_add_match_subsystem:
325 * @udev_enumerate: context
326 * @subsystem: filter for a subsystem of the device to include in the list
328 * Returns: 0 on success, otherwise a negative error value.
330 int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
332 if (udev_enumerate == NULL)
334 if (subsystem == NULL)
336 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
337 &udev_enumerate->subsystem_match_list, subsystem, NULL, 1, 0) == NULL)
343 * udev_enumerate_add_nomatch_subsystem:
344 * @udev_enumerate: context
345 * @subsystem: filter for a subsystem of the device to exclude from the list
347 * Returns: 0 on success, otherwise a negative error value.
349 int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
351 if (udev_enumerate == NULL)
353 if (subsystem == NULL)
355 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
356 &udev_enumerate->subsystem_nomatch_list, subsystem, NULL, 1, 0) == NULL)
362 * udev_enumerate_add_match_sysattr:
363 * @udev_enumerate: context
364 * @sysattr: filter for a sys attribute at the device to include in the list
365 * @value: optional value of the sys attribute
367 * Returns: 0 on success, otherwise a negative error value.
369 int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
371 if (udev_enumerate == NULL)
375 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
376 &udev_enumerate->sysattr_match_list, sysattr, value, 0, 0) == NULL)
382 * udev_enumerate_add_nomatch_sysattr:
383 * @udev_enumerate: context
384 * @sysattr: filter for a sys attribute at the device to exclude from the list
385 * @value: optional value of the sys attribute
387 * Returns: 0 on success, otherwise a negative error value.
389 int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
391 if (udev_enumerate == NULL)
395 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
396 &udev_enumerate->sysattr_nomatch_list, sysattr, value, 0, 0) == NULL)
401 static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val)
403 const char *val = NULL;
406 val = udev_device_get_sysattr_value(dev, sysattr);
409 if (match_val == NULL) {
413 if (fnmatch(match_val, val, 0) == 0) {
422 * udev_enumerate_add_match_property:
423 * @udev_enumerate: context
424 * @property: filter for a property of the device to include in the list
425 * @value: value of the property
427 * Returns: 0 on success, otherwise a negative error value.
429 int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value)
431 if (udev_enumerate == NULL)
433 if (property == NULL)
435 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
436 &udev_enumerate->properties_match_list, property, value, 0, 0) == NULL)
442 * udev_enumerate_add_match_tag:
443 * @udev_enumerate: context
444 * @tag: filter for a tag of the device to include in the list
446 * Returns: 0 on success, otherwise a negative error value.
448 int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag)
450 if (udev_enumerate == NULL)
454 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
455 &udev_enumerate->tags_match_list, tag, NULL, 1, 0) == NULL)
461 * udev_enumerate_add_match_is_initialized:
462 * @udev_enumerate: context
464 * Match only devices which udev has set up already. This makes
465 * sure, that the device node permissions and context are properly set
466 * and that network devices are fully renamed.
468 * Usually, devices which are found in the kernel but not already
469 * handled by udev, have still pending events. Services should subscribe
470 * to monitor events and wait for these devices to become ready, instead
471 * of using uninitialized devices.
473 * For now, this will not affect devices which do not have a device node
474 * and are not network interfaces.
476 * Returns: 0 on success, otherwise a negative error value.
478 int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
480 if (udev_enumerate == NULL)
482 udev_enumerate->match_is_initialized = true;
487 * udev_enumerate_add_match_sysname:
488 * @udev_enumerate: context
489 * @sysname: filter for the name of the device to include in the list
491 * Returns: 0 on success, otherwise a negative error value.
493 int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
495 if (udev_enumerate == NULL)
499 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
500 &udev_enumerate->sysname_match_list, sysname, NULL, 1, 0) == NULL)
505 static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
507 struct udev_list_entry *list_entry;
510 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
511 if (match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
512 udev_list_entry_get_value(list_entry)))
516 if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
517 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
518 /* anything that does not match, will make it FALSE */
519 if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
520 udev_list_entry_get_value(list_entry)))
528 static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
530 struct udev_list_entry *list_entry;
533 /* no match always matches */
534 if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
537 /* loop over matches */
538 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
539 const char *match_key = udev_list_entry_get_name(list_entry);
540 const char *match_value = udev_list_entry_get_value(list_entry);
541 struct udev_list_entry *property_entry;
543 /* loop over device properties */
544 udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) {
545 const char *dev_key = udev_list_entry_get_name(property_entry);
546 const char *dev_value = udev_list_entry_get_value(property_entry);
548 if (fnmatch(match_key, dev_key, 0) != 0)
550 if (match_value == NULL && dev_value == NULL) {
554 if (match_value == NULL || dev_value == NULL)
556 if (fnmatch(match_value, dev_value, 0) == 0) {
566 static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
568 struct udev_list_entry *list_entry;
570 /* no match always matches */
571 if (udev_list_get_entry(&udev_enumerate->tags_match_list) == NULL)
574 /* loop over matches */
575 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list))
576 if (!udev_device_has_tag(dev, udev_list_entry_get_name(list_entry)))
582 static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
584 struct udev_list_entry *list_entry;
586 if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL)
589 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) {
590 if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0)
597 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
598 const char *basedir, const char *subdir1, const char *subdir2)
600 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
601 char path[UTIL_PATH_SIZE];
608 l = util_strpcpyl(&s, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL);
610 l = util_strpcpyl(&s, l, "/", subdir1, NULL);
612 util_strpcpyl(&s, l, "/", subdir2, NULL);
616 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
617 char syspath[UTIL_PATH_SIZE];
618 struct udev_device *dev;
620 if (dent->d_name[0] == '.')
623 if (!match_sysname(udev_enumerate, dent->d_name))
626 util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
627 dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
631 if (udev_enumerate->match_is_initialized) {
633 * All devices with a device node or network interfaces
634 * possibly need udev to adjust the device node permission
635 * or context, or rename the interface before it can be
636 * reliably used from other processes.
638 * For now, we can only check these types of devices, we
639 * might not store a database, and have no way to find out
640 * for all other types of devices.
642 if (!udev_device_get_is_initialized(dev) &&
643 (major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0))
646 if (!match_tag(udev_enumerate, dev))
648 if (!match_property(udev_enumerate, dev))
650 if (!match_sysattr(udev_enumerate, dev))
653 syspath_add(udev_enumerate, udev_device_get_syspath(dev));
655 udev_device_unref(dev);
661 static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
663 struct udev_list_entry *list_entry;
665 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
666 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
669 if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
670 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
671 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
679 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
681 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
683 char path[UTIL_PATH_SIZE];
687 util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL);
691 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
692 if (dent->d_name[0] == '.')
694 if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
696 scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
703 * udev_enumerate_add_syspath:
704 * @udev_enumerate: context
705 * @syspath: path of a device
707 * Add a device to the list of devices, to retrieve it back sorted in dependency order.
709 * Returns: 0 on success, otherwise a negative error value.
711 int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
713 struct udev_device *udev_device;
715 if (udev_enumerate == NULL)
719 /* resolve to real syspath */
720 udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
721 if (udev_device == NULL)
723 syspath_add(udev_enumerate, udev_device_get_syspath(udev_device));
724 udev_device_unref(udev_device);
729 * udev_enumerate_scan_devices:
730 * @udev_enumerate: udev enumeration context
732 * Returns: 0 on success, otherwise a negative error value.
734 int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
736 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
737 char base[UTIL_PATH_SIZE];
740 if (udev_enumerate == NULL)
743 if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL) {
744 struct udev_list_entry *list_entry;
746 /* scan only tagged devices, use tags reverse-index, instead of searching all devices in /sys */
747 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) {
750 char path[UTIL_PATH_SIZE];
752 util_strscpyl(path, sizeof(path), udev_get_dev_path(udev), "/.udev/tags/",
753 udev_list_entry_get_name(list_entry), NULL);
757 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
758 struct udev_device *dev;
760 if (dent->d_name[0] == '.')
763 dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name);
766 syspath_add(udev_enumerate, udev_device_get_syspath(dev));
767 udev_device_unref(dev);
772 util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL);
773 if (stat(base, &statbuf) == 0) {
774 /* we have /subsystem/, forget all the old stuff */
775 dbg(udev, "searching '/subsystem/*/devices/*' dir\n");
776 scan_dir(udev_enumerate, "subsystem", "devices", NULL);
778 dbg(udev, "searching '/bus/*/devices/*' dir\n");
779 scan_dir(udev_enumerate, "bus", "devices", NULL);
780 dbg(udev, "searching '/class/*' dir\n");
781 scan_dir(udev_enumerate, "class", NULL, NULL);
789 * udev_enumerate_scan_subsystems:
790 * @udev_enumerate: udev enumeration context
792 * Returns: 0 on success, otherwise a negative error value.
794 int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
796 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
797 char base[UTIL_PATH_SIZE];
799 const char *subsysdir;
801 if (udev_enumerate == NULL)
804 util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL);
805 if (stat(base, &statbuf) == 0)
806 subsysdir = "subsystem";
809 if (match_subsystem(udev_enumerate, "subsystem")) {
810 dbg(udev, "searching '%s/*' dir\n", subsysdir);
811 scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
813 if (match_subsystem(udev_enumerate, "drivers")) {
814 dbg(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
815 scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");