udev: move libudev, gudev to src/; move gudev/docs/, udev/docs/ to to docs/

1 files changed, 936 insertions, 0 deletions

diff --git a/src/libudev/libudev-enumerate.c b/src/libudev/libudev-enumerate.c
new file mode 100644
index 0000000000..7b9a732ce6
--- /dev/null
+++ b/src/libudev/libudev-enumerate.c
@@ -0,0 +1,936 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * 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
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <fnmatch.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/param.h>
+
+#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 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;
+        bool devices_uptodate:1;
+        bool match_is_initialized;
+};
+
+/**
+ * udev_enumerate_new:
+ * @udev: udev library context
+ *
+ * Returns: an enumeration context
+ **/
+_public_ 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, &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;
+}
+
+/**
+ * udev_enumerate_ref:
+ * @udev_enumerate: context
+ *
+ * Take a reference of a enumeration context.
+ *
+ * Returns: the passed enumeration context
+ **/
+_public_ 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.
+ **/
+_public_ 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(&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);
+        free(udev_enumerate);
+}
+
+/**
+ * udev_enumerate_get_udev:
+ * @udev_enumerate: context
+ *
+ * Returns: the udev library context.
+ */
+_public_ 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)
+                        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.
+ */
+_public_ 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(&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->devices_list, move_later->syspath, NULL);
+                                move_later = NULL;
+                        }
+
+                        udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
+                }
+
+                if (move_later)
+                        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->devices_list, entry->syspath, NULL);
+                        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.
+ */
+_public_ 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->subsystem_match_list, subsystem, NULL) == 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.
+ */
+_public_ 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->subsystem_nomatch_list, subsystem, NULL) == 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.
+ */
+_public_ 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->sysattr_match_list, sysattr, value) == 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.
+ */
+_public_ 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->sysattr_nomatch_list, sysattr, value) == 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.
+ */
+_public_ 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->properties_match_list, property, value) == 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.
+ */
+_public_ 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->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.
+ */
+_public_ 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
+ *
+ * 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.
+ */
+_public_ 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.
+ */
+_public_ 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->sysname_match_list, sysname, NULL) == 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_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;
+
+        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_parent(udev_enumerate, dev))
+                        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.
+ */
+_public_ 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;
+}
+
+static int scan_devices_tags(struct udev_enumerate *udev_enumerate)
+{
+        struct udev *udev = udev_enumerate_get_udev(udev_enumerate);
+        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_parent(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 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 */
+                scan_dir(udev_enumerate, "subsystem", "devices", NULL);
+        } else {
+                scan_dir(udev_enumerate, "bus", "devices", NULL);
+                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.
+ **/
+_public_ 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.
+ **/
+_public_ 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;
+
+        /* all kernel modules */
+        if (match_subsystem(udev_enumerate, "module"))
+                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"))
+                scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
+
+        /* all subsystem drivers */
+        if (match_subsystem(udev_enumerate, "drivers"))
+                scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");
+        return 0;
+}