2 * libudev - interface to udev device information
4 * Copyright (C) 2008 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 devices_list;
55 struct syspath *devices;
56 unsigned int devices_cur;
57 unsigned int devices_max;
58 bool devices_uptodate:1;
63 * @udev: udev library context
65 * Returns: an enumeration context
67 struct udev_enumerate *udev_enumerate_new(struct udev *udev)
69 struct udev_enumerate *udev_enumerate;
71 udev_enumerate = calloc(1, sizeof(struct udev_enumerate));
72 if (udev_enumerate == NULL)
74 udev_enumerate->refcount = 1;
75 udev_enumerate->udev = udev;
76 udev_list_init(&udev_enumerate->sysattr_match_list);
77 udev_list_init(&udev_enumerate->sysattr_nomatch_list);
78 udev_list_init(&udev_enumerate->subsystem_match_list);
79 udev_list_init(&udev_enumerate->subsystem_nomatch_list);
80 udev_list_init(&udev_enumerate->sysname_match_list);
81 udev_list_init(&udev_enumerate->properties_match_list);
82 udev_list_init(&udev_enumerate->devices_list);
83 return udev_enumerate;
88 * @udev_enumerate: context
90 * Take a reference of a enumeration context.
92 * Returns: the passed enumeration context
94 struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
96 if (udev_enumerate == NULL)
98 udev_enumerate->refcount++;
99 return udev_enumerate;
103 * udev_enumerate_unref:
104 * @udev_enumerate: context
106 * Drop a reference of an enumeration context. If the refcount reaches zero,
107 * all resources of the enumeration context will be released.
109 void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
113 if (udev_enumerate == NULL)
115 udev_enumerate->refcount--;
116 if (udev_enumerate->refcount > 0)
118 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_match_list);
119 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_nomatch_list);
120 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_match_list);
121 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_nomatch_list);
122 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysname_match_list);
123 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->properties_match_list);
124 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
125 for (i = 0; i < udev_enumerate->devices_cur; i++)
126 free(udev_enumerate->devices[i].syspath);
127 free(udev_enumerate->devices);
128 free(udev_enumerate);
132 * udev_enumerate_get_udev:
133 * @udev_enumerate: context
135 * Returns: the udev library context.
137 struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
139 if (udev_enumerate == NULL)
141 return udev_enumerate->udev;
144 static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath)
147 struct syspath *entry;
149 /* double array size if needed */
150 if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) {
154 add = udev_enumerate->devices_max;
157 buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath));
160 udev_enumerate->devices = buf;
161 udev_enumerate->devices_max += add;
164 path = strdup(syspath);
167 entry = &udev_enumerate->devices[udev_enumerate->devices_cur];
168 entry->syspath = path;
169 entry->len = strlen(path);
170 udev_enumerate->devices_cur++;
171 udev_enumerate->devices_uptodate = false;
175 static int syspath_cmp(const void *p1, const void *p2)
177 const struct syspath *path1 = p1;
178 const struct syspath *path2 = p2;
182 len = MIN(path1->len, path2->len);
183 ret = memcmp(path1->syspath, path2->syspath, len);
185 if (path1->len < path2->len)
187 else if (path1->len > path2->len)
193 /* For devices that should be moved to the absolute end of the list */
194 static int devices_delay_end(struct udev *udev, const char *syspath)
196 static const char *delay_device_list[] = {
204 len = strlen(udev_get_sys_path(udev));
205 for (i = 0; delay_device_list[i] != NULL; i++) {
206 if (strstr(&syspath[len], delay_device_list[i]) != NULL) {
207 dbg(udev, "delaying: %s\n", syspath);
214 /* For devices that should just be moved a little bit later, just
215 * before the point where some common path prefix changes. Returns the
216 * number of characters that make up that common prefix */
217 static size_t devices_delay_later(struct udev *udev, const char *syspath)
221 /* For sound cards the control device must be enumerated last
222 * to make sure it's the final device node that gets ACLs
223 * applied. Applications rely on this fact and use ACL changes
224 * on the control node as an indicator that the ACL change of
225 * the entire sound card completed. The kernel makes this
226 * guarantee when creating those devices, and hence we should
227 * too when enumerating them. */
229 if ((c = strstr(syspath, "/sound/card"))) {
231 c += strcspn(c, "/");
233 if (strncmp(c, "/controlC", 9) == 0)
234 return c - syspath + 1;
241 * udev_enumerate_get_list_entry:
242 * @udev_enumerate: context
244 * Returns: the first entry of the sorted list of device paths.
246 struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
248 if (udev_enumerate == NULL)
250 if (!udev_enumerate->devices_uptodate) {
253 struct syspath *prev = NULL, *move_later = NULL;
255 udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
256 qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
258 max = udev_enumerate->devices_cur;
259 for (i = 0; i < max; i++) {
260 struct syspath *entry = &udev_enumerate->devices[i];
261 size_t move_later_prefix = 0;
263 /* skip duplicated entries */
265 entry->len == prev->len &&
266 memcmp(entry->syspath, prev->syspath, entry->len) == 0)
270 /* skip to be delayed devices, and add them to the end of the list */
271 if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
272 syspath_add(udev_enumerate, entry->syspath);
276 /* skip to be delayed devices, and move the to
277 * the point where the prefix changes. We can
278 * only move one item at a time. */
280 move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
282 if (move_later_prefix > 0) {
289 strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) {
291 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
292 move_later->syspath, NULL, 0, 0);
296 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
297 entry->syspath, NULL, 0, 0);
301 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
302 move_later->syspath, NULL, 0, 0);
304 /* add and cleanup delayed devices from end of list */
305 for (i = max; i < udev_enumerate->devices_cur; i++) {
306 struct syspath *entry = &udev_enumerate->devices[i];
308 udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
309 entry->syspath, NULL, 0, 0);
310 free(entry->syspath);
312 udev_enumerate->devices_cur = max;
314 udev_enumerate->devices_uptodate = true;
316 return udev_list_get_entry(&udev_enumerate->devices_list);
320 * udev_enumerate_add_match_subsystem:
321 * @udev_enumerate: context
322 * @subsystem: filter for a subsystem of the device to include in the list
324 * Returns: 0 on success, otherwise a negative error value.
326 int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
328 if (udev_enumerate == NULL)
330 if (subsystem == NULL)
332 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
333 &udev_enumerate->subsystem_match_list, subsystem, NULL, 1, 0) == NULL)
339 * udev_enumerate_add_nomatch_subsystem:
340 * @udev_enumerate: context
341 * @subsystem: filter for a subsystem of the device to exclude from the list
343 * Returns: 0 on success, otherwise a negative error value.
345 int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
347 if (udev_enumerate == NULL)
349 if (subsystem == NULL)
351 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
352 &udev_enumerate->subsystem_nomatch_list, subsystem, NULL, 1, 0) == NULL)
358 * udev_enumerate_add_match_sysattr:
359 * @udev_enumerate: context
360 * @sysattr: filter for a sys attribute at the device to include in the list
361 * @value: optional value of the sys attribute
363 * Returns: 0 on success, otherwise a negative error value.
365 int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
367 if (udev_enumerate == NULL)
371 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
372 &udev_enumerate->sysattr_match_list, sysattr, value, 0, 0) == NULL)
378 * udev_enumerate_add_nomatch_sysattr:
379 * @udev_enumerate: context
380 * @sysattr: filter for a sys attribute at the device to exclude from the list
381 * @value: optional value of the sys attribute
383 * Returns: 0 on success, otherwise a negative error value.
385 int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
387 if (udev_enumerate == NULL)
391 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
392 &udev_enumerate->sysattr_nomatch_list, sysattr, value, 0, 0) == NULL)
397 static int match_sysattr_value(struct udev *udev, const char *syspath, const char *sysattr, const char *match_val)
399 struct udev_device *device;
400 const char *val = NULL;
403 device = udev_device_new_from_syspath(udev, syspath);
406 val = udev_device_get_sysattr_value(device, sysattr);
409 if (match_val == NULL) {
413 if (fnmatch(match_val, val, 0) == 0) {
418 udev_device_unref(device);
423 * udev_enumerate_add_match_property:
424 * @udev_enumerate: context
425 * @property: filter for a property of the device to include in the list
426 * @value: value of the property
428 * Returns: 0 on success, otherwise a negative error value.
430 int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value)
432 if (udev_enumerate == NULL)
434 if (property == NULL)
436 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
437 &udev_enumerate->properties_match_list, property, value, 0, 0) == NULL)
443 * udev_enumerate_add_match_sysname:
444 * @udev_enumerate: context
445 * @sysname: filter for the name of the device to include in the list
447 * Returns: 0 on success, otherwise a negative error value.
449 int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
451 if (udev_enumerate == NULL)
455 if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate),
456 &udev_enumerate->sysname_match_list, sysname, NULL, 1, 0) == NULL)
461 static int match_sysattr(struct udev_enumerate *udev_enumerate, const char *syspath)
463 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
464 struct udev_list_entry *list_entry;
467 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
468 if (match_sysattr_value(udev, syspath,
469 udev_list_entry_get_name(list_entry),
470 udev_list_entry_get_value(list_entry)))
474 if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
475 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
476 /* anything that does not match, will make it FALSE */
477 if (!match_sysattr_value(udev, syspath,
478 udev_list_entry_get_name(list_entry),
479 udev_list_entry_get_value(list_entry)))
487 static int match_property(struct udev_enumerate *udev_enumerate, const char *syspath)
489 struct udev_device *dev;
490 struct udev_list_entry *list_entry;
493 /* no match always matches */
494 if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
497 /* no device does not match */
498 dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
502 /* loop over matches */
503 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
504 const char *match_key = udev_list_entry_get_name(list_entry);
505 const char *match_value = udev_list_entry_get_value(list_entry);
506 struct udev_list_entry *property_entry;
508 /* loop over device properties */
509 udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) {
510 const char *dev_key = udev_list_entry_get_name(property_entry);
511 const char *dev_value = udev_list_entry_get_value(property_entry);
513 if (fnmatch(match_key, dev_key, 0) != 0)
515 if (match_value == NULL && dev_value == NULL) {
519 if (match_value == NULL || dev_value == NULL)
521 if (fnmatch(match_value, dev_value, 0) == 0) {
528 udev_device_unref(dev);
532 static int match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
534 struct udev_list_entry *list_entry;
536 if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL)
539 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) {
540 if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0)
547 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
548 const char *basedir, const char *subdir1, const char *subdir2)
550 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
551 char path[UTIL_PATH_SIZE];
558 l = util_strpcpyl(&s, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL);
560 l = util_strpcpyl(&s, l, "/", subdir1, NULL);
562 util_strpcpyl(&s, l, "/", subdir2, NULL);
566 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
567 char syspath[UTIL_PATH_SIZE];
568 char filename[UTIL_PATH_SIZE];
571 if (dent->d_name[0] == '.')
573 if (!match_sysname(udev_enumerate, dent->d_name))
576 util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
577 if (lstat(syspath, &statbuf) != 0)
579 if (S_ISREG(statbuf.st_mode))
581 if (S_ISLNK(statbuf.st_mode))
582 util_resolve_sys_link(udev, syspath, sizeof(syspath));
584 util_strscpyl(filename, sizeof(filename), syspath, "/uevent", NULL);
585 if (stat(filename, &statbuf) != 0)
587 if (!match_sysattr(udev_enumerate, syspath))
589 if (!match_property(udev_enumerate, syspath))
591 syspath_add(udev_enumerate, syspath);
597 static int match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
599 struct udev_list_entry *list_entry;
601 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
602 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
605 if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
606 udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
607 if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
615 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
617 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
619 char path[UTIL_PATH_SIZE];
623 util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL);
627 for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
628 if (dent->d_name[0] == '.')
630 if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
632 scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
639 * udev_enumerate_add_syspath:
640 * @udev_enumerate: context
641 * @syspath: path of a device
643 * Add a device to the list of devices, to retrieve it back sorted in dependency order.
645 * Returns: 0 on success, otherwise a negative error value.
647 int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
649 struct udev_device *udev_device;
651 if (udev_enumerate == NULL)
655 /* resolve to real syspath */
656 udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
657 if (udev_device == NULL)
659 syspath_add(udev_enumerate, udev_device_get_syspath(udev_device));
660 udev_device_unref(udev_device);
665 * udev_enumerate_scan_devices:
666 * @udev_enumerate: udev enumeration context
668 * Returns: 0 on success, otherwise a negative error value.
670 int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
672 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
673 char base[UTIL_PATH_SIZE];
676 if (udev_enumerate == NULL)
678 util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL);
679 if (stat(base, &statbuf) == 0) {
680 /* we have /subsystem/, forget all the old stuff */
681 dbg(udev, "searching '/subsystem/*/devices/*' dir\n");
682 scan_dir(udev_enumerate, "subsystem", "devices", NULL);
684 dbg(udev, "searching '/bus/*/devices/*' dir\n");
685 scan_dir(udev_enumerate, "bus", "devices", NULL);
686 dbg(udev, "searching '/class/*' dir\n");
687 scan_dir(udev_enumerate, "class", NULL, NULL);
688 /* if block isn't a class, scan /block/ */
689 util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/class/block", NULL);
690 if (stat(base, &statbuf) != 0) {
691 if (match_subsystem(udev_enumerate, "block")) {
692 dbg(udev, "searching '/block/*' dir\n");
694 scan_dir_and_add_devices(udev_enumerate, "block", NULL, NULL);
695 /* scan partitions */
696 dbg(udev, "searching '/block/*/*' dir\n");
697 scan_dir(udev_enumerate, "block", NULL, "block");
705 * udev_enumerate_scan_subsystems:
706 * @udev_enumerate: udev enumeration context
708 * Returns: 0 on success, otherwise a negative error value.
710 int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
712 struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
713 char base[UTIL_PATH_SIZE];
715 const char *subsysdir;
717 if (udev_enumerate == NULL)
719 util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL);
720 if (stat(base, &statbuf) == 0)
721 subsysdir = "subsystem";
724 if (match_subsystem(udev_enumerate, "subsystem")) {
725 dbg(udev, "searching '%s/*' dir\n", subsysdir);
726 scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
728 if (match_subsystem(udev_enumerate, "drivers")) {
729 dbg(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
730 scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");