X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=blobdiff_plain;f=libudev%2Flibudev-enumerate.c;h=0b028bab8477614c2ffb5b2531a5613bf7ff69fa;hp=96cf0609073dd283695338c76219d3aff61b3f4a;hb=325293609392d0feba7a31ca9ed0940c8509c2ea;hpb=cf5bd04073671df31dbbaf525f870366b37e5256

diff --git a/libudev/libudev-enumerate.c b/libudev/libudev-enumerate.c
index 96cf06090..0b028bab8 100644
--- a/libudev/libudev-enumerate.c
+++ b/libudev/libudev-enumerate.c
@@ -1,7 +1,7 @@
 /*
  * libudev - interface to udev device information
  *
- * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
@@ -51,11 +51,13 @@ struct udev_enumerate {
 	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;
 };
 
 /**
@@ -64,7 +66,7 @@ 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;
 
@@ -79,6 +81,7 @@ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
 	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;
 }
@@ -91,7 +94,7 @@ 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;
@@ -106,7 +109,7 @@ 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;
 
@@ -121,6 +124,7 @@ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
 	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);
@@ -134,7 +138,7 @@ 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;
@@ -190,7 +194,8 @@ static int syspath_cmp(const void *p1, const void *p2)
 	return ret;
 }
 
-static int devices_delay(struct udev *udev, const char *syspath)
+/* 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",
@@ -204,9 +209,35 @@ static int devices_delay(struct udev *udev, const char *syspath)
 	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 1;
+			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;
 }
 
@@ -216,14 +247,15 @@ static int devices_delay(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;
 	if (!udev_enumerate->devices_uptodate) {
 		unsigned int i;
 		unsigned int max;
-		struct syspath *prev = NULL;
+		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);
@@ -240,20 +272,47 @@ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *ude
 			prev = entry;
 
 			/* skip to be delayed devices, and add them to the end of the list */
-			if (devices_delay(udev_enumerate->udev, entry->syspath)) {
+			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);
+				move_later = NULL;
+			}
+
 			udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
-					    entry->syspath, NULL, 0, 0);
+					    entry->syspath, NULL, 0);
 		}
+
+		if (move_later)
+			udev_list_entry_add(udev_enumerate->udev, &udev_enumerate->devices_list,
+					    move_later->syspath, NULL, 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);
+					    entry->syspath, NULL, 0);
 			free(entry->syspath);
 		}
 		udev_enumerate->devices_cur = max;
@@ -270,14 +329,14 @@ 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)
+				&udev_enumerate->subsystem_match_list, subsystem, NULL, UDEV_LIST_UNIQUE) == NULL)
 		return -ENOMEM;
 	return 0;
 }
@@ -289,14 +348,14 @@ 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)
+				&udev_enumerate->subsystem_nomatch_list, subsystem, NULL, UDEV_LIST_UNIQUE) == NULL)
 		return -ENOMEM;
 	return 0;
 }
@@ -309,14 +368,14 @@ 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)
+				&udev_enumerate->sysattr_match_list, sysattr, value, 0) == NULL)
 		return -ENOMEM;
 	return 0;
 }
@@ -329,28 +388,24 @@ 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)
+			   &udev_enumerate->sysattr_nomatch_list, sysattr, value, 0) == NULL)
 		return -ENOMEM;
 	return 0;
 }
 
-static int match_sysattr_value(struct udev *udev, const char *syspath, const char *sysattr, const char *match_val)
+static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val)
 {
-	struct udev_device *device;
 	const char *val = NULL;
 	bool match = false;
 
-	device = udev_device_new_from_syspath(udev, syspath);
-	if (device == NULL)
-		return -EINVAL;
-	val = udev_device_get_sysattr_value(device, sysattr);
+	val = udev_device_get_sysattr_value(dev, sysattr);
 	if (val == NULL)
 		goto exit;
 	if (match_val == NULL) {
@@ -362,7 +417,6 @@ static int match_sysattr_value(struct udev *udev, const char *syspath, const cha
 		goto exit;
 	}
 exit:
-	udev_device_unref(device);
 	return match;
 }
 
@@ -374,18 +428,63 @@ 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)
+				&udev_enumerate->properties_match_list, property, value, 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.
+ */
+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, UDEV_LIST_UNIQUE) == 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.
+ */
+UDEV_EXPORT 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
@@ -393,58 +492,49 @@ 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_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)
+				&udev_enumerate->sysname_match_list, sysname, NULL, UDEV_LIST_UNIQUE) == NULL)
 		return -ENOMEM;
 	return 0;
 }
 
-static int match_sysattr(struct udev_enumerate *udev_enumerate, const char *syspath)
+static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 {
-	struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 	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(udev, syspath,
-				     udev_list_entry_get_name(list_entry),
-				     udev_list_entry_get_value(list_entry)))
-			return 0;
+		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(udev, syspath,
-					      udev_list_entry_get_name(list_entry),
-					      udev_list_entry_get_value(list_entry)))
-				return 0;
+			if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
+						 udev_list_entry_get_value(list_entry)))
+				return false;
 		}
-		return 1;
+		return true;
 	}
-	return 1;
+	return true;
 }
 
-static int match_property(struct udev_enumerate *udev_enumerate, const char *syspath)
+static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
 {
-	struct udev_device *dev;
 	struct udev_list_entry *list_entry;
-	int match = false;
+	bool match = false;
 
 	/* no match always matches */
 	if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
-		return 1;
-
-	/* no device does not match */
-	dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
-	if (dev == NULL)
-		return 0;
+		return true;
 
 	/* loop over matches */
 	udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
@@ -472,23 +562,38 @@ static int match_property(struct udev_enumerate *udev_enumerate, const char *sys
 		}
 	}
 out:
-	udev_device_unref(dev);
 	return match;
 }
 
-static int match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
+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 1;
+		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 1;
+		return true;
 	}
-	return 0;
+	return false;
 }
 
 static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
@@ -506,57 +611,71 @@ static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
 	if (subdir1 != NULL)
 		l = util_strpcpyl(&s, l, "/", subdir1, NULL);
 	if (subdir2 != NULL)
-		l = util_strpcpyl(&s, l, "/", subdir2, NULL);
+		util_strpcpyl(&s, l, "/", subdir2, NULL);
 	dir = opendir(path);
 	if (dir == NULL)
-		return -1;
+		return -ENOENT;
 	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
 		char syspath[UTIL_PATH_SIZE];
-		char filename[UTIL_PATH_SIZE];
-		struct stat statbuf;
+		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);
-		if (lstat(syspath, &statbuf) != 0)
-			continue;
-		if (S_ISREG(statbuf.st_mode))
+		dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
+		if (dev == NULL)
 			continue;
-		if (S_ISLNK(statbuf.st_mode))
-			util_resolve_sys_link(udev, syspath, sizeof(syspath));
 
-		util_strscpyl(filename, sizeof(filename), syspath, "/uevent", NULL);
-		if (stat(filename, &statbuf) != 0)
-			continue;
-		if (!match_sysattr(udev_enumerate, syspath))
-			continue;
-		if (!match_property(udev_enumerate, syspath))
-			continue;
-		syspath_add(udev_enumerate, syspath);
+		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 int match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
+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 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 1;
+				return true;
 		}
-		return 0;
+		return false;
 	}
-	return 1;
+	return true;
 }
 
 static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
@@ -591,7 +710,7 @@ 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;
 
@@ -614,7 +733,7 @@ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char
  *
  * Returns: 0 on success, otherwise a negative error value.
  **/
-int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
+UDEV_EXPORT int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
 {
 	struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
 	char base[UTIL_PATH_SIZE];
@@ -622,29 +741,60 @@ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
 
 	if (udev_enumerate == NULL)
 		return -EINVAL;
-	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);
+
+	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_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;
+
+				if (dent->d_name[0] == '.')
+					continue;
+
+				dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name);
+				if (dev == NULL)
+					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_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);
+		}
 	} 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);
-		/* if block isn't a class, scan /block/ */
-		util_strscpyl(base, sizeof(base), udev_get_sys_path(udev), "/class/block", NULL);
-		if (stat(base, &statbuf) != 0) {
-			if (match_subsystem(udev_enumerate, "block")) {
-				dbg(udev, "searching '/block/*' dir\n");
-				/* scan disks */
-				scan_dir_and_add_devices(udev_enumerate, "block", NULL, NULL);
-				/* scan partitions */
-				dbg(udev, "searching '/block/*/*' dir\n");
-				scan_dir(udev_enumerate, "block", NULL, "block");
-			}
+			scan_dir(udev_enumerate, "bus", "devices", NULL);
+			dbg(udev, "searching '/class/*' dir\n");
+			scan_dir(udev_enumerate, "class", NULL, NULL);
 		}
 	}
+
 	return 0;
 }
 
@@ -654,7 +804,7 @@ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
  *
  * 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];
@@ -663,15 +813,26 @@ 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");