/* * libudev - interface to udev device information * * Copyright (C) 2008-2010 Kay Sievers * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #include #include #include #include "libudev.h" #include "libudev-private.h" /** * SECTION:libudev-enumerate * @short_description: lookup and sort sys devices * * Lookup devices in the sys filesystem, filter devices by properties, * and return a sorted list of devices. */ struct syspath { char *syspath; size_t len; }; /** * udev_enumerate: * * Opaque object representing one device lookup/sort context. */ struct udev_enumerate { struct udev *udev; int refcount; struct udev_list_node sysattr_match_list; struct udev_list_node sysattr_nomatch_list; struct udev_list_node subsystem_match_list; struct udev_list_node subsystem_nomatch_list; struct udev_list_node sysname_match_list; struct udev_list_node properties_match_list; struct udev_list_node tags_match_list; struct udev_list_node devices_list; struct syspath *devices; unsigned int devices_cur; unsigned int devices_max; bool devices_uptodate:1; bool match_is_initialized; }; /** * udev_enumerate_new: * @udev: udev library context * * Returns: an enumeration context **/ struct udev_enumerate *udev_enumerate_new(struct udev *udev) { struct udev_enumerate *udev_enumerate; udev_enumerate = calloc(1, sizeof(struct udev_enumerate)); if (udev_enumerate == NULL) return NULL; udev_enumerate->refcount = 1; udev_enumerate->udev = udev; udev_list_init(&udev_enumerate->sysattr_match_list); udev_list_init(&udev_enumerate->sysattr_nomatch_list); udev_list_init(&udev_enumerate->subsystem_match_list); udev_list_init(&udev_enumerate->subsystem_nomatch_list); udev_list_init(&udev_enumerate->sysname_match_list); udev_list_init(&udev_enumerate->properties_match_list); udev_list_init(&udev_enumerate->tags_match_list); udev_list_init(&udev_enumerate->devices_list); return udev_enumerate; } /** * udev_enumerate_ref: * @udev_enumerate: context * * Take a reference of a enumeration context. * * Returns: the passed enumeration context **/ struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate) { if (udev_enumerate == NULL) return NULL; udev_enumerate->refcount++; return udev_enumerate; } /** * udev_enumerate_unref: * @udev_enumerate: context * * Drop a reference of an enumeration context. If the refcount reaches zero, * all resources of the enumeration context will be released. **/ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate) { unsigned int i; if (udev_enumerate == NULL) return; udev_enumerate->refcount--; if (udev_enumerate->refcount > 0) return; udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_match_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysattr_nomatch_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_match_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->subsystem_nomatch_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->sysname_match_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->properties_match_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->tags_match_list); udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list); for (i = 0; i < udev_enumerate->devices_cur; i++) free(udev_enumerate->devices[i].syspath); free(udev_enumerate->devices); free(udev_enumerate); } /** * udev_enumerate_get_udev: * @udev_enumerate: context * * Returns: the udev library context. */ struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate) { if (udev_enumerate == NULL) return NULL; return udev_enumerate->udev; } static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath) { char *path; struct syspath *entry; /* double array size if needed */ if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) { struct syspath *buf; unsigned int add; add = udev_enumerate->devices_max; if (add < 1024) add = 1024; buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath)); if (buf == NULL) return -ENOMEM; udev_enumerate->devices = buf; udev_enumerate->devices_max += add; } path = strdup(syspath); if (path == NULL) return -ENOMEM; entry = &udev_enumerate->devices[udev_enumerate->devices_cur]; entry->syspath = path; entry->len = strlen(path); udev_enumerate->devices_cur++; udev_enumerate->devices_uptodate = false; return 0; } static int syspath_cmp(const void *p1, const void *p2) { const struct syspath *path1 = p1; const struct syspath *path2 = p2; size_t len; int ret; len = MIN(path1->len, path2->len); ret = memcmp(path1->syspath, path2->syspath, len); if (ret == 0) { if (path1->len < path2->len) ret = -1; else if (path1->len > path2->len) ret = 1; } return ret; } /* For devices that should be moved to the absolute end of the list */ static bool devices_delay_end(struct udev *udev, const char *syspath) { static const char *delay_device_list[] = { "/block/md", "/block/dm-", NULL }; size_t len; int i; len = strlen(udev_get_sys_path(udev)); for (i = 0; delay_device_list[i] != NULL; i++) { if (strstr(&syspath[len], delay_device_list[i]) != NULL) { dbg(udev, "delaying: %s\n", syspath); return true; } } return false; } /* For devices that should just be moved a little bit later, just * before the point where some common path prefix changes. Returns the * number of characters that make up that common prefix */ static size_t devices_delay_later(struct udev *udev, const char *syspath) { const char *c; /* For sound cards the control device must be enumerated last * to make sure it's the final device node that gets ACLs * applied. Applications rely on this fact and use ACL changes * on the control node as an indicator that the ACL change of * the entire sound card completed. The kernel makes this * guarantee when creating those devices, and hence we should * too when enumerating them. */ if ((c = strstr(syspath, "/sound/card"))) { c += 11; c += strcspn(c, "/"); if (strncmp(c, "/controlC", 9) == 0) return c - syspath + 1; } return 0; } /** * udev_enumerate_get_list_entry: * @udev_enumerate: context * * Returns: the first entry of the sorted list of device paths. */ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate) { if (udev_enumerate == NULL) return NULL; if (!udev_enumerate->devices_uptodate) { unsigned int i; unsigned int max; struct syspath *prev = NULL, *move_later = NULL; size_t move_later_prefix = 0; udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list); qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp); max = udev_enumerate->devices_cur; for (i = 0; i < max; i++) { struct syspath *entry = &udev_enumerate->devices[i]; /* skip duplicated entries */ if (prev != NULL && entry->len == prev->len && memcmp(entry->syspath, prev->syspath, entry->len) == 0) continue; prev = entry; /* skip to be delayed devices, and add them to the end of the list */ if (devices_delay_end(udev_enumerate->udev, entry->syspath)) { syspath_add(udev_enumerate, entry->syspath); /* need to update prev here for the case realloc() gives a different address */ prev = &udev_enumerate->devices[i]; continue; } /* skip to be delayed devices, and move the to * the point where the prefix changes. We can * only move one item at a time. */ if (!move_later) { move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath); if (move_later_prefix > 0) { move_later = entry; continue; } } if (move_later && strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) { udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list, move_later->syspath, NULL, 0, 0); move_later = NULL; } udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list, entry->syspath, NULL, 0, 0); } if (move_later) udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list, move_later->syspath, NULL, 0, 0); /* add and cleanup delayed devices from end of list */ for (i = max; i < udev_enumerate->devices_cur; i++) { struct syspath *entry = &udev_enumerate->devices[i]; udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list, entry->syspath, NULL, 0, 0); free(entry->syspath); } udev_enumerate->devices_cur = max; udev_enumerate->devices_uptodate = true; } return udev_list_get_entry(&udev_enumerate->devices_list); } /** * udev_enumerate_add_match_subsystem: * @udev_enumerate: context * @subsystem: filter for a subsystem of the device to include in the list * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem) { if (udev_enumerate == NULL) return -EINVAL; if (subsystem == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->subsystem_match_list, subsystem, NULL, 1, 0) == NULL) return -ENOMEM; return 0; } /** * udev_enumerate_add_nomatch_subsystem: * @udev_enumerate: context * @subsystem: filter for a subsystem of the device to exclude from the list * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem) { if (udev_enumerate == NULL) return -EINVAL; if (subsystem == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->subsystem_nomatch_list, subsystem, NULL, 1, 0) == NULL) return -ENOMEM; return 0; } /** * udev_enumerate_add_match_sysattr: * @udev_enumerate: context * @sysattr: filter for a sys attribute at the device to include in the list * @value: optional value of the sys attribute * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value) { if (udev_enumerate == NULL) return -EINVAL; if (sysattr == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->sysattr_match_list, sysattr, value, 0, 0) == NULL) return -ENOMEM; return 0; } /** * udev_enumerate_add_nomatch_sysattr: * @udev_enumerate: context * @sysattr: filter for a sys attribute at the device to exclude from the list * @value: optional value of the sys attribute * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value) { if (udev_enumerate == NULL) return -EINVAL; if (sysattr == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->sysattr_nomatch_list, sysattr, value, 0, 0) == NULL) return -ENOMEM; return 0; } static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val) { const char *val = NULL; bool match = false; val = udev_device_get_sysattr_value(dev, sysattr); if (val == NULL) goto exit; if (match_val == NULL) { match = true; goto exit; } if (fnmatch(match_val, val, 0) == 0) { match = true; goto exit; } exit: return match; } /** * udev_enumerate_add_match_property: * @udev_enumerate: context * @property: filter for a property of the device to include in the list * @value: value of the property * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value) { if (udev_enumerate == NULL) return -EINVAL; if (property == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->properties_match_list, property, value, 0, 0) == NULL) return -ENOMEM; return 0; } /** * udev_enumerate_add_match_tag: * @udev_enumerate: context * @tag: filter for a tag of the device to include in the list * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag) { if (udev_enumerate == NULL) return -EINVAL; if (tag == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->tags_match_list, tag, NULL, 1, 0) == NULL) return -ENOMEM; return 0; } /** * udev_enumerate_add_match_is_initialized: * @udev_enumerate: context * * Match only devices which udev has set up already. This makes * sure, that the device node permissions and context are properly set * and that network devices are fully renamed. * * Usually, devices which are found in the kernel but not already * handled by udev, have still pending events. Services should subscribe * to monitor events and wait for these devices to become ready, instead * of using uninitialized devices. * * For now, this will not affect devices which do not have a device node * and are not network interfaces. * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate) { if (udev_enumerate == NULL) return -EINVAL; udev_enumerate->match_is_initialized = true; return 0; } /** * udev_enumerate_add_match_sysname: * @udev_enumerate: context * @sysname: filter for the name of the device to include in the list * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname) { if (udev_enumerate == NULL) return -EINVAL; if (sysname == NULL) return 0; if (udev_list_entry_add(udev_enumerate_get_udev(udev_enumerate), &udev_enumerate->sysname_match_list, sysname, NULL, 1, 0) == NULL) return -ENOMEM; return 0; } static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev) { struct udev_list_entry *list_entry; /* skip list */ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) { if (match_sysattr_value(dev, udev_list_entry_get_name(list_entry), udev_list_entry_get_value(list_entry))) return false; } /* include list */ if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) { udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) { /* anything that does not match, will make it FALSE */ if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry), udev_list_entry_get_value(list_entry))) return false; } return true; } return true; } static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev) { struct udev_list_entry *list_entry; bool match = false; /* no match always matches */ if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL) return true; /* loop over matches */ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) { const char *match_key = udev_list_entry_get_name(list_entry); const char *match_value = udev_list_entry_get_value(list_entry); struct udev_list_entry *property_entry; /* loop over device properties */ udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) { const char *dev_key = udev_list_entry_get_name(property_entry); const char *dev_value = udev_list_entry_get_value(property_entry); if (fnmatch(match_key, dev_key, 0) != 0) continue; if (match_value == NULL && dev_value == NULL) { match = true; goto out; } if (match_value == NULL || dev_value == NULL) continue; if (fnmatch(match_value, dev_value, 0) == 0) { match = true; goto out; } } } out: return match; } static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device *dev) { struct udev_list_entry *list_entry; /* no match always matches */ if (udev_list_get_entry(&udev_enumerate->tags_match_list) == NULL) return true; /* loop over matches */ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) if (!udev_device_has_tag(dev, udev_list_entry_get_name(list_entry))) return false; return true; } static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname) { struct udev_list_entry *list_entry; if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL) return true; udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) { if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0) continue; return true; } return false; } static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir1, const char *subdir2) { struct udev *udev = udev_enumerate_get_udev(udev_enumerate); char path[UTIL_PATH_SIZE]; size_t l; char *s; DIR *dir; struct dirent *dent; s = path; l = util_strpcpyl(&s, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL); if (subdir1 != NULL) l = util_strpcpyl(&s, l, "/", subdir1, NULL); if (subdir2 != NULL) util_strpcpyl(&s, l, "/", subdir2, NULL); dir = opendir(path); if (dir == NULL) return -ENOENT; for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) { char syspath[UTIL_PATH_SIZE]; struct udev_device *dev; if (dent->d_name[0] == '.') continue; if (!match_sysname(udev_enumerate, dent->d_name)) continue; util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL); dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath); if (dev == NULL) continue; if (udev_enumerate->match_is_initialized) { /* * All devices with a device node or network interfaces * possibly need udev to adjust the device node permission * or context, or rename the interface before it can be * reliably used from other processes. * * For now, we can only check these types of devices, we * might not store a database, and have no way to find out * for all other types of devices. */ if (!udev_device_get_is_initialized(dev) && (major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0)) goto nomatch; } if (!match_tag(udev_enumerate, dev)) goto nomatch; if (!match_property(udev_enumerate, dev)) goto nomatch; if (!match_sysattr(udev_enumerate, dev)) goto nomatch; syspath_add(udev_enumerate, udev_device_get_syspath(dev)); nomatch: udev_device_unref(dev); } closedir(dir); return 0; } static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem) { struct udev_list_entry *list_entry; udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) { if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0) return false; } if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) { udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) { if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0) return true; } return false; } return true; } static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem) { struct udev *udev = udev_enumerate_get_udev(udev_enumerate); char path[UTIL_PATH_SIZE]; DIR *dir; struct dirent *dent; util_strscpyl(path, sizeof(path), udev_get_sys_path(udev), "/", basedir, NULL); dir = opendir(path); if (dir == NULL) return -1; for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) { if (dent->d_name[0] == '.') continue; if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name)) continue; scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir); } closedir(dir); return 0; } /** * udev_enumerate_add_syspath: * @udev_enumerate: context * @syspath: path of a device * * Add a device to the list of devices, to retrieve it back sorted in dependency order. * * Returns: 0 on success, otherwise a negative error value. */ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath) { struct udev_device *udev_device; if (udev_enumerate == NULL) return -EINVAL; if (syspath == NULL) return 0; /* resolve to real syspath */ udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath); if (udev_device == NULL) return -EINVAL; syspath_add(udev_enumerate, udev_device_get_syspath(udev_device)); udev_device_unref(udev_device); return 0; } /** * udev_enumerate_scan_devices: * @udev_enumerate: udev enumeration context * * Returns: 0 on success, otherwise a negative error value. **/ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate) { struct udev *udev = udev_enumerate_get_udev(udev_enumerate); char base[UTIL_PATH_SIZE]; struct stat statbuf; if (udev_enumerate == NULL) return -EINVAL; if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL) { struct udev_list_entry *list_entry; /* scan only tagged devices, use tags reverse-index, instead of searching all devices in /sys */ udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) { DIR *dir; struct dirent *dent; char path[UTIL_PATH_SIZE]; util_strscpyl(path, sizeof(path), udev_get_dev_path(udev), "/.run/udev/tags/", udev_list_entry_get_name(list_entry), NULL); dir = opendir(path); if (dir == NULL) continue; for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) { struct udev_device *dev; if (dent->d_name[0] == '.') continue; dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name); if (dev == NULL) continue; syspath_add(udev_enumerate, udev_device_get_syspath(dev)); udev_device_unref(dev); } closedir(dir); } } else { util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL); if (stat(base, &statbuf) == 0) { /* we have /subsystem/, forget all the old stuff */ dbg(udev, "searching '/subsystem/*/devices/*' dir\n"); scan_dir(udev_enumerate, "subsystem", "devices", NULL); } else { dbg(udev, "searching '/bus/*/devices/*' dir\n"); scan_dir(udev_enumerate, "bus", "devices", NULL); dbg(udev, "searching '/class/*' dir\n"); scan_dir(udev_enumerate, "class", NULL, NULL); } } return 0; } /** * udev_enumerate_scan_subsystems: * @udev_enumerate: udev enumeration context * * Returns: 0 on success, otherwise a negative error value. **/ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate) { struct udev *udev = udev_enumerate_get_udev(udev_enumerate); char base[UTIL_PATH_SIZE]; struct stat statbuf; const char *subsysdir; if (udev_enumerate == NULL) return -EINVAL; util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL); if (stat(base, &statbuf) == 0) subsysdir = "subsystem"; else subsysdir = "bus"; if (match_subsystem(udev_enumerate, "subsystem")) { dbg(udev, "searching '%s/*' dir\n", subsysdir); scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL); } if (match_subsystem(udev_enumerate, "drivers")) { dbg(udev, "searching '%s/*/drivers/*' dir\n", subsysdir); scan_dir(udev_enumerate, subsysdir, "drivers", "drivers"); } return 0; }