chiark / gitweb /
rules: switch to built-in blkid
[elogind.git] / libudev / libudev-enumerate.c
index 128813c7d618717690f79d0eca82776a6c4fa011..f14d5c8f57cf168a806c4438624b47c1e7f4dae4 100644 (file)
@@ -45,14 +45,15 @@ struct syspath {
 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 udev_list sysattr_match_list;
+       struct udev_list sysattr_nomatch_list;
+       struct udev_list subsystem_match_list;
+       struct udev_list subsystem_nomatch_list;
+       struct udev_list sysname_match_list;
+       struct udev_list properties_match_list;
+       struct udev_list tags_match_list;
+       struct udev_device *parent_match;
+       struct udev_list devices_list;
        struct syspath *devices;
        unsigned int devices_cur;
        unsigned int devices_max;
@@ -66,7 +67,7 @@ struct udev_enumerate {
  *
  * Returns: an enumeration context
  **/
-struct udev_enumerate *udev_enumerate_new(struct udev *udev)
+UDEV_EXPORT struct udev_enumerate *udev_enumerate_new(struct udev *udev)
 {
        struct udev_enumerate *udev_enumerate;
 
@@ -75,14 +76,14 @@ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
                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);
+       udev_list_init(udev, &udev_enumerate->sysattr_match_list, false);
+       udev_list_init(udev, &udev_enumerate->sysattr_nomatch_list, false);
+       udev_list_init(udev, &udev_enumerate->subsystem_match_list, true);
+       udev_list_init(udev, &udev_enumerate->subsystem_nomatch_list, true);
+       udev_list_init(udev, &udev_enumerate->sysname_match_list, true);
+       udev_list_init(udev, &udev_enumerate->properties_match_list, false);
+       udev_list_init(udev, &udev_enumerate->tags_match_list, true);
+       udev_list_init(udev, &udev_enumerate->devices_list, false);
        return udev_enumerate;
 }
 
@@ -94,7 +95,7 @@ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
  *
  * Returns: the passed enumeration context
  **/
-struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
+UDEV_EXPORT struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
 {
        if (udev_enumerate == NULL)
                return NULL;
@@ -109,7 +110,7 @@ struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
  * 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)
+UDEV_EXPORT void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
 {
        unsigned int i;
 
@@ -118,14 +119,15 @@ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
        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);
+       udev_list_cleanup(&udev_enumerate->sysattr_match_list);
+       udev_list_cleanup(&udev_enumerate->sysattr_nomatch_list);
+       udev_list_cleanup(&udev_enumerate->subsystem_match_list);
+       udev_list_cleanup(&udev_enumerate->subsystem_nomatch_list);
+       udev_list_cleanup(&udev_enumerate->sysname_match_list);
+       udev_list_cleanup(&udev_enumerate->properties_match_list);
+       udev_list_cleanup(&udev_enumerate->tags_match_list);
+       udev_device_unref(udev_enumerate->parent_match);
+       udev_list_cleanup(&udev_enumerate->devices_list);
        for (i = 0; i < udev_enumerate->devices_cur; i++)
                free(udev_enumerate->devices[i].syspath);
        free(udev_enumerate->devices);
@@ -138,7 +140,7 @@ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
  *
  * Returns: the udev library context.
  */
-struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
+UDEV_EXPORT struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
 {
        if (udev_enumerate == NULL)
                return NULL;
@@ -247,7 +249,7 @@ static size_t devices_delay_later(struct udev *udev, const char *syspath)
  *
  * 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)
+UDEV_EXPORT struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
 {
        if (udev_enumerate == NULL)
                return NULL;
@@ -257,7 +259,7 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
                struct syspath *prev = NULL, *move_later = NULL;
                size_t move_later_prefix = 0;
 
-               udev_list_cleanup_entries(udev_enumerate->udev, &udev_enumerate->devices_list);
+               udev_list_cleanup(&udev_enumerate->devices_list);
                qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
 
                max = udev_enumerate->devices_cur;
@@ -294,25 +296,21 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
                        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);
+                               udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
                                move_later = NULL;
                        }
 
-                       udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
-                                           entry->syspath, NULL, 0, 0);
+                       udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
                }
 
                if (move_later)
-                       udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
-                                           move_later->syspath, NULL, 0, 0);
+                       udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
 
                /* 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);
+                       udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
                        free(entry->syspath);
                }
                udev_enumerate->devices_cur = max;
@@ -329,14 +327,13 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->subsystem_match_list, subsystem, NULL) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -348,14 +345,13 @@ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, co
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->subsystem_nomatch_list, subsystem, NULL) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -368,14 +364,13 @@ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate,
  *
  * 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)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->sysattr_match_list, sysattr, value) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -388,14 +383,13 @@ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, cons
  *
  * 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)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->sysattr_nomatch_list, sysattr, value) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -428,14 +422,13 @@ exit:
  *
  * 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)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->properties_match_list, property, value) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -447,18 +440,42 @@ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, con
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->tags_match_list, tag, NULL) == NULL)
                return -ENOMEM;
        return 0;
 }
 
+/**
+ * udev_enumerate_add_match_parent:
+ * @udev_enumerate: context
+ * @parent: parent device where to start searching
+ *
+ * Return the devices on the subtree of one given device. The parent
+ * itself is included in the list.
+ *
+ * A reference for the device is held until the udev_enumerate context
+ * is cleaned up.
+ *
+ * Returns: 0 on success, otherwise a negative error value.
+ */
+UDEV_EXPORT int udev_enumerate_add_match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *parent)
+{
+       if (udev_enumerate == NULL)
+               return -EINVAL;
+       if (parent == NULL)
+               return 0;
+       if (udev_enumerate->parent_match != NULL)
+               udev_device_unref(udev_enumerate->parent_match);
+       udev_enumerate->parent_match = udev_device_ref(parent);
+       return 0;
+}
+
 /**
  * udev_enumerate_add_match_is_initialized:
  * @udev_enumerate: context
@@ -477,7 +494,7 @@ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const ch
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
+UDEV_EXPORT int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
 {
        if (udev_enumerate == NULL)
                return -EINVAL;
@@ -492,14 +509,13 @@ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerat
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
+UDEV_EXPORT 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)
+       if (udev_list_entry_add(&udev_enumerate->sysname_match_list, sysname, NULL) == NULL)
                return -ENOMEM;
        return 0;
 }
@@ -581,6 +597,17 @@ static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device
        return true;
 }
 
+static bool match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
+{
+       const char *parent;
+
+       if (udev_enumerate->parent_match == NULL)
+               return true;
+
+       parent = udev_device_get_devpath(udev_enumerate->parent_match);
+       return strncmp(parent, udev_device_get_devpath(dev), strlen(parent)) == 0;
+}
+
 static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
 {
        struct udev_list_entry *list_entry;
@@ -645,6 +672,8 @@ static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
                            (major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0))
                                goto nomatch;
                }
+               if (!match_parent(udev_enumerate, dev))
+                       goto nomatch;
                if (!match_tag(udev_enumerate, dev))
                        goto nomatch;
                if (!match_property(udev_enumerate, dev))
@@ -710,7 +739,7 @@ static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir,
  *
  * Returns: 0 on success, otherwise a negative error value.
  */
-int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
+UDEV_EXPORT int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
 {
        struct udev_device *udev_device;
 
@@ -727,73 +756,161 @@ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char
        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)
+static int scan_devices_tags(struct udev_enumerate *udev_enumerate)
 {
        struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
-       char base[UTIL_PATH_SIZE];
-       struct stat statbuf;
+       struct udev_list_entry *list_entry;
 
-       if (udev_enumerate == NULL)
-               return -EINVAL;
+       /* 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];
 
-       if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL) {
-               struct udev_list_entry *list_entry;
+               util_strscpyl(path, sizeof(path), udev_get_run_path(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;
 
-               /* 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];
+                       if (dent->d_name[0] == '.')
+                               continue;
 
-                       util_strscpyl(path, sizeof(path), udev_get_dev_path(udev), "/.udev/tags/",
-                                     udev_list_entry_get_name(list_entry), NULL);
-                       dir = opendir(path);
-                       if (dir == NULL)
+                       dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name);
+                       if (dev == NULL)
                                continue;
-                       for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
-                               struct udev_device *dev;
 
-                               if (dent->d_name[0] == '.')
-                                       continue;
+                       if (!match_subsystem(udev_enumerate, udev_device_get_subsystem(dev)))
+                               goto nomatch;
+                       if (!match_sysname(udev_enumerate, udev_device_get_sysname(dev)))
+                               goto nomatch;
+                       if (!match_parent(udev_enumerate, dev))
+                               goto nomatch;
+                       if (!match_property(udev_enumerate, dev))
+                               goto nomatch;
+                       if (!match_sysattr(udev_enumerate, dev))
+                               goto nomatch;
 
-                               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);
+                       syspath_add(udev_enumerate, udev_device_get_syspath(dev));
+nomatch:
+                       udev_device_unref(dev);
                }
+               closedir(dir);
+       }
+       return 0;
+}
+
+static int parent_add_child(struct udev_enumerate *enumerate, const char *path)
+{
+       struct udev_device *dev;
+
+       dev = udev_device_new_from_syspath(enumerate->udev, path);
+       if (dev == NULL)
+               return -ENODEV;
+
+       if (!match_subsystem(enumerate, udev_device_get_subsystem(dev)))
+               return 0;
+       if (!match_sysname(enumerate, udev_device_get_sysname(dev)))
+               return 0;
+       if (!match_property(enumerate, dev))
+               return 0;
+       if (!match_sysattr(enumerate, dev))
+               return 0;
+
+       syspath_add(enumerate, udev_device_get_syspath(dev));
+       udev_device_unref(dev);
+       return 1;
+}
+
+static int parent_crawl_children(struct udev_enumerate *enumerate, const char *path, int maxdepth)
+{
+       DIR *d;
+       struct dirent *dent;
+
+       d = opendir(path);
+       if (d == NULL)
+               return -errno;
+
+       for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
+               char *child;
+
+               if (dent->d_name[0] == '.')
+                       continue;
+               if (dent->d_type != DT_DIR)
+                       continue;
+               if (asprintf(&child, "%s/%s", path, dent->d_name) < 0)
+                       continue;
+               parent_add_child(enumerate, child);
+               if (maxdepth > 0)
+                       parent_crawl_children(enumerate, child, maxdepth-1);
+               free(child);
+       }
+
+       closedir(d);
+       return 0;
+}
+
+static int scan_devices_children(struct udev_enumerate *enumerate)
+{
+       const char *path;
+
+       path = udev_device_get_syspath(enumerate->parent_match);
+       parent_add_child(enumerate, path);
+       return parent_crawl_children(enumerate, path, 256);
+}
+
+static int scan_devices_all(struct udev_enumerate *udev_enumerate)
+{
+       struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
+       char base[UTIL_PATH_SIZE];
+       struct stat statbuf;
+
+       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 {
-               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);
-               }
+               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_devices:
+ * @udev_enumerate: udev enumeration context
+ *
+ * Returns: 0 on success, otherwise a negative error value.
+ **/
+UDEV_EXPORT int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
+{
+       if (udev_enumerate == NULL)
+               return -EINVAL;
+
+       /* efficiently lookup tags only, we maintain a reverse-index */
+       if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL)
+               return scan_devices_tags(udev_enumerate);
+
+       /* walk the subtree of one parent device only */
+       if (udev_enumerate->parent_match != NULL)
+               return scan_devices_children(udev_enumerate);
+
+       /* scan devices of all subsystems */
+       return scan_devices_all(udev_enumerate);
+}
+
 /**
  * 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)
+UDEV_EXPORT int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
 {
        struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
        char base[UTIL_PATH_SIZE];
@@ -803,15 +920,25 @@ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
        if (udev_enumerate == NULL)
                return -EINVAL;
 
+       /* all kernel modules */
+       if (match_subsystem(udev_enumerate, "module")) {
+               dbg(udev, "searching '%s/modules/*' dir\n", subsysdir);
+               scan_dir_and_add_devices(udev_enumerate, "module", NULL, NULL);
+       }
+
        util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/subsystem", NULL);
        if (stat(base, &statbuf) == 0)
                subsysdir = "subsystem";
        else
                subsysdir = "bus";
+
+       /* all subsystems (only buses support coldplug) */
        if (match_subsystem(udev_enumerate, "subsystem")) {
                dbg(udev, "searching '%s/*' dir\n", subsysdir);
                scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
        }
+
+       /* all subsystem drivers */
        if (match_subsystem(udev_enumerate, "drivers")) {
                dbg(udev, "searching '%s/*/drivers/*' dir\n", subsysdir);
                scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");