1 files changed, 836 insertions, 0 deletions
diff --git a/src/libudev/libudev-device.c b/src/libudev/libudev-device.c
new file mode 100644
index 0000000..1e7d774
--- /dev/null
+++ b/src/libudev/libudev-device.c
@@ -0,0 +1,836 @@
+/* SPDX-License-Identifier: LGPL-2.1+ */
+
+#include <ctype.h>
+#include <dirent.h>
+#include <errno.h>
+#include <fcntl.h>
+#include <linux/sockios.h>
+#include <net/if.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "libudev.h"
+#include "sd-device.h"
+
+#include "alloc-util.h"
+#include "device-private.h"
+#include "device-util.h"
+#include "libudev-device-internal.h"
+#include "parse-util.h"
+#include "time-util.h"
+
+/**
+ * SECTION:libudev-device
+ * @short_description: kernel sys devices
+ *
+ * Representation of kernel sys devices. Devices are uniquely identified
+ * by their syspath, every device has exactly one path in the kernel sys
+ * filesystem. Devices usually belong to a kernel subsystem, and have
+ * a unique name inside that subsystem.
+ */
+
+/**
+ * udev_device_get_seqnum:
+ * @udev_device: udev device
+ *
+ * This is only valid if the device was received through a monitor. Devices read from
+ * sys do not have a sequence number.
+ *
+ * Returns: the kernel event sequence number, or 0 if there is no sequence number available.
+ **/
+_public_ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device) {
+        const char *seqnum;
+        unsigned long long ret;
+        int r;
+
+        assert_return_errno(udev_device, 0, EINVAL);
+
+        r = sd_device_get_property_value(udev_device->device, "SEQNUM", &seqnum);
+        if (r == -ENOENT)
+                return 0;
+        else if (r < 0)
+                return_with_errno(0, r);
+
+        r = safe_atollu(seqnum, &ret);
+        if (r < 0)
+                return_with_errno(0, r);
+
+        return ret;
+}
+
+/**
+ * udev_device_get_devnum:
+ * @udev_device: udev device
+ *
+ * Get the device major/minor number.
+ *
+ * Returns: the dev_t number.
+ **/
+_public_ dev_t udev_device_get_devnum(struct udev_device *udev_device) {
+        dev_t devnum;
+        int r;
+
+        assert_return_errno(udev_device, makedev(0, 0), EINVAL);
+
+        r = sd_device_get_devnum(udev_device->device, &devnum);
+        if (r == -ENOENT)
+                return makedev(0, 0);
+        if (r < 0)
+                return_with_errno(makedev(0, 0), r);
+
+        return devnum;
+}
+
+/**
+ * udev_device_get_driver:
+ * @udev_device: udev device
+ *
+ * Get the kernel driver name.
+ *
+ * Returns: the driver name string, or #NULL if there is no driver attached.
+ **/
+_public_ const char *udev_device_get_driver(struct udev_device *udev_device) {
+        const char *driver;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_driver(udev_device->device, &driver);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return driver;
+}
+
+/**
+ * udev_device_get_devtype:
+ * @udev_device: udev device
+ *
+ * Retrieve the devtype string of the udev device.
+ *
+ * Returns: the devtype name of the udev device, or #NULL if it cannot be determined
+ **/
+_public_ const char *udev_device_get_devtype(struct udev_device *udev_device) {
+        const char *devtype;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devtype(udev_device->device, &devtype);
+        if (r == -ENOENT)
+                return NULL;
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return devtype;
+}
+
+/**
+ * udev_device_get_subsystem:
+ * @udev_device: udev device
+ *
+ * Retrieve the subsystem string of the udev device. The string does not
+ * contain any "/".
+ *
+ * Returns: the subsystem name of the udev device, or #NULL if it cannot be determined
+ **/
+_public_ const char *udev_device_get_subsystem(struct udev_device *udev_device) {
+        const char *subsystem;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_subsystem(udev_device->device, &subsystem);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return subsystem;
+}
+
+/**
+ * udev_device_get_property_value:
+ * @udev_device: udev device
+ * @key: property name
+ *
+ * Get the value of a given property.
+ *
+ * Returns: the property string, or #NULL if there is no such property.
+ **/
+_public_ const char *udev_device_get_property_value(struct udev_device *udev_device, const char *key) {
+        const char *value;
+        int r;
+
+        assert_return_errno(udev_device && key, NULL, EINVAL);
+
+        r = sd_device_get_property_value(udev_device->device, key, &value);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return value;
+}
+
+struct udev_device *udev_device_new(struct udev *udev, sd_device *device) {
+        struct udev_device *udev_device;
+
+        assert(device);
+
+        udev_device = new(struct udev_device, 1);
+        if (!udev_device)
+                return_with_errno(NULL, ENOMEM);
+
+        *udev_device = (struct udev_device) {
+                .n_ref = 1,
+                .udev = udev,
+                .device = sd_device_ref(device),
+        };
+
+        udev_list_init(&udev_device->properties, true);
+        udev_list_init(&udev_device->tags, true);
+        udev_list_init(&udev_device->sysattrs, true);
+        udev_list_init(&udev_device->devlinks, true);
+
+        return udev_device;
+}
+
+/**
+ * udev_device_new_from_syspath:
+ * @udev: udev library context
+ * @syspath: sys device path including sys directory
+ *
+ * Create new udev device, and fill in information from the sys
+ * device and the udev database entry. The syspath is the absolute
+ * path to the device, including the sys mount point.
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
+_public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        r = sd_device_new_from_syspath(&device, syspath);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(udev, device);
+}
+
+/**
+ * udev_device_new_from_devnum:
+ * @udev: udev library context
+ * @type: char or block device
+ * @devnum: device major/minor number
+ *
+ * Create new udev device, and fill in information from the sys
+ * device and the udev database entry. The device is looked-up
+ * by its major/minor number and type. Character and block device
+ * numbers are not unique across the two types.
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
+_public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        r = sd_device_new_from_devnum(&device, type, devnum);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(udev, device);
+}
+
+/**
+ * udev_device_new_from_device_id:
+ * @udev: udev library context
+ * @id: text string identifying a kernel device
+ *
+ * Create new udev device, and fill in information from the sys
+ * device and the udev database entry. The device is looked-up
+ * by a special string:
+ *   b8:2          - block device major:minor
+ *   c128:1        - char device major:minor
+ *   n3            - network device ifindex
+ *   +sound:card29 - kernel driver core subsystem:device name
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
+_public_ struct udev_device *udev_device_new_from_device_id(struct udev *udev, const char *id) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        r = sd_device_new_from_device_id(&device, id);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(udev, device);
+}
+
+/**
+ * udev_device_new_from_subsystem_sysname:
+ * @udev: udev library context
+ * @subsystem: the subsystem of the device
+ * @sysname: the name of the device
+ *
+ * Create new udev device, and fill in information from the sys device
+ * and the udev database entry. The device is looked up by the subsystem
+ * and name string of the device, like "mem" / "zero", or "block" / "sda".
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
+_public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        r = sd_device_new_from_subsystem_sysname(&device, subsystem, sysname);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(udev, device);
+}
+
+/**
+ * udev_device_new_from_environment
+ * @udev: udev library context
+ *
+ * Create new udev device, and fill in information from the
+ * current process environment. This only works reliable if
+ * the process is called from a udev rule. It is usually used
+ * for tools executed from IMPORT= rules.
+ *
+ * The initial refcount is 1, and needs to be decremented to
+ * release the resources of the udev device.
+ *
+ * Returns: a new udev device, or #NULL, if it does not exist
+ **/
+_public_ struct udev_device *udev_device_new_from_environment(struct udev *udev) {
+        _cleanup_(sd_device_unrefp) sd_device *device = NULL;
+        int r;
+
+        r = device_new_from_strv(&device, environ);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(udev, device);
+}
+
+static struct udev_device *device_new_from_parent(struct udev_device *child) {
+        sd_device *parent;
+        int r;
+
+        assert_return_errno(child, NULL, EINVAL);
+
+        r = sd_device_get_parent(child->device, &parent);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return udev_device_new(child->udev, parent);
+}
+
+/**
+ * udev_device_get_parent:
+ * @udev_device: the device to start searching from
+ *
+ * Find the next parent device, and fill in information from the sys
+ * device and the udev database entry.
+ *
+ * Returned device is not referenced. It is attached to the child
+ * device, and will be cleaned up when the child device is cleaned up.
+ *
+ * It is not necessarily just the upper level directory, empty or not
+ * recognized sys directories are ignored.
+ *
+ * It can be called as many times as needed, without caring about
+ * references.
+ *
+ * Returns: a new udev device, or #NULL, if it no parent exist.
+ **/
+_public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (!udev_device->parent_set) {
+                udev_device->parent_set = true;
+                udev_device->parent = device_new_from_parent(udev_device);
+        }
+
+        /* TODO: errno will differ here in case parent == NULL */
+        return udev_device->parent;
+}
+
+/**
+ * udev_device_get_parent_with_subsystem_devtype:
+ * @udev_device: udev device to start searching from
+ * @subsystem: the subsystem of the device
+ * @devtype: the type (DEVTYPE) of the device
+ *
+ * Find the next parent device, with a matching subsystem and devtype
+ * value, and fill in information from the sys device and the udev
+ * database entry.
+ *
+ * If devtype is #NULL, only subsystem is checked, and any devtype will
+ * match.
+ *
+ * Returned device is not referenced. It is attached to the child
+ * device, and will be cleaned up when the child device is cleaned up.
+ *
+ * It can be called as many times as needed, without caring about
+ * references.
+ *
+ * Returns: a new udev device, or #NULL if no matching parent exists.
+ **/
+_public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype) {
+        sd_device *parent;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        /* this relies on the fact that finding the subdevice of a parent or the
+           parent of a subdevice commute */
+
+        /* first find the correct sd_device */
+        r = sd_device_get_parent_with_subsystem_devtype(udev_device->device, subsystem, devtype, &parent);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        /* then walk the chain of udev_device parents until the corresponding
+           one is found */
+        while ((udev_device = udev_device_get_parent(udev_device)))
+                if (udev_device->device == parent)
+                        return udev_device;
+
+        return_with_errno(NULL, ENOENT);
+}
+
+/**
+ * udev_device_get_udev:
+ * @udev_device: udev device
+ *
+ * Retrieve the udev library context the device was created with.
+ *
+ * Returns: the udev library context
+ **/
+_public_ struct udev *udev_device_get_udev(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        return udev_device->udev;
+}
+
+static struct udev_device *udev_device_free(struct udev_device *udev_device) {
+        assert(udev_device);
+
+        sd_device_unref(udev_device->device);
+        udev_device_unref(udev_device->parent);
+
+        udev_list_cleanup(&udev_device->properties);
+        udev_list_cleanup(&udev_device->sysattrs);
+        udev_list_cleanup(&udev_device->tags);
+        udev_list_cleanup(&udev_device->devlinks);
+
+        return mfree(udev_device);
+}
+
+/**
+ * udev_device_ref:
+ * @udev_device: udev device
+ *
+ * Take a reference of a udev device.
+ *
+ * Returns: the passed udev device
+ **/
+
+/**
+ * udev_device_unref:
+ * @udev_device: udev device
+ *
+ * Drop a reference of a udev device. If the refcount reaches zero,
+ * the resources of the device will be released.
+ *
+ * Returns: #NULL
+ **/
+DEFINE_PUBLIC_TRIVIAL_REF_UNREF_FUNC(struct udev_device, udev_device, udev_device_free);
+
+/**
+ * udev_device_get_devpath:
+ * @udev_device: udev device
+ *
+ * Retrieve the kernel devpath value of the udev device. The path
+ * does not contain the sys mount point, and starts with a '/'.
+ *
+ * Returns: the devpath of the udev device
+ **/
+_public_ const char *udev_device_get_devpath(struct udev_device *udev_device) {
+        const char *devpath;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devpath(udev_device->device, &devpath);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return devpath;
+}
+
+/**
+ * udev_device_get_syspath:
+ * @udev_device: udev device
+ *
+ * Retrieve the sys path of the udev device. The path is an
+ * absolute path and starts with the sys mount point.
+ *
+ * Returns: the sys path of the udev device
+ **/
+_public_ const char *udev_device_get_syspath(struct udev_device *udev_device) {
+        const char *syspath;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_syspath(udev_device->device, &syspath);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return syspath;
+}
+
+/**
+ * udev_device_get_sysname:
+ * @udev_device: udev device
+ *
+ * Get the kernel device name in /sys.
+ *
+ * Returns: the name string of the device
+ **/
+_public_ const char *udev_device_get_sysname(struct udev_device *udev_device) {
+        const char *sysname;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_sysname(udev_device->device, &sysname);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return sysname;
+}
+
+/**
+ * udev_device_get_sysnum:
+ * @udev_device: udev device
+ *
+ * Get the instance number of the device.
+ *
+ * Returns: the trailing number string of the device name
+ **/
+_public_ const char *udev_device_get_sysnum(struct udev_device *udev_device) {
+        const char *sysnum;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_sysnum(udev_device->device, &sysnum);
+        if (r == -ENOENT)
+                return NULL;
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return sysnum;
+}
+
+/**
+ * udev_device_get_devnode:
+ * @udev_device: udev device
+ *
+ * Retrieve the device node file name belonging to the udev device.
+ * The path is an absolute path, and starts with the device directory.
+ *
+ * Returns: the device node file name of the udev device, or #NULL if no device node exists
+ **/
+_public_ const char *udev_device_get_devnode(struct udev_device *udev_device) {
+        const char *devnode;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devname(udev_device->device, &devnode);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return devnode;
+}
+
+/**
+ * udev_device_get_devlinks_list_entry:
+ * @udev_device: udev device
+ *
+ * Retrieve the list of device links pointing to the device file of
+ * the udev device. The next list entry can be retrieved with
+ * udev_list_entry_get_next(), which returns #NULL if no more entries exist.
+ * The devlink path can be retrieved from the list entry by
+ * udev_list_entry_get_name(). The path is an absolute path, and starts with
+ * the device directory.
+ *
+ * Returns: the first entry of the device node link list
+ **/
+_public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (device_get_devlinks_generation(udev_device->device) != udev_device->devlinks_generation ||
+            !udev_device->devlinks_read) {
+                const char *devlink;
+
+                udev_list_cleanup(&udev_device->devlinks);
+
+                FOREACH_DEVICE_DEVLINK(udev_device->device, devlink)
+                        if (!udev_list_entry_add(&udev_device->devlinks, devlink, NULL))
+                                return_with_errno(NULL, ENOMEM);
+
+                udev_device->devlinks_read = true;
+                udev_device->devlinks_generation = device_get_devlinks_generation(udev_device->device);
+        }
+
+        return udev_list_get_entry(&udev_device->devlinks);
+}
+
+/**
+ * udev_device_get_event_properties_entry:
+ * @udev_device: udev device
+ *
+ * Retrieve the list of key/value device properties of the udev
+ * device. The next list entry can be retrieved with udev_list_entry_get_next(),
+ * which returns #NULL if no more entries exist. The property name
+ * can be retrieved from the list entry by udev_list_entry_get_name(),
+ * the property value by udev_list_entry_get_value().
+ *
+ * Returns: the first entry of the property list
+ **/
+_public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (device_get_properties_generation(udev_device->device) != udev_device->properties_generation ||
+            !udev_device->properties_read) {
+                const char *key, *value;
+
+                udev_list_cleanup(&udev_device->properties);
+
+                FOREACH_DEVICE_PROPERTY(udev_device->device, key, value)
+                        if (!udev_list_entry_add(&udev_device->properties, key, value))
+                                return_with_errno(NULL, ENOMEM);
+
+                udev_device->properties_read = true;
+                udev_device->properties_generation = device_get_properties_generation(udev_device->device);
+        }
+
+        return udev_list_get_entry(&udev_device->properties);
+}
+
+/**
+ * udev_device_get_action:
+ * @udev_device: udev device
+ *
+ * This is only valid if the device was received through a monitor. Devices read from
+ * sys do not have an action string. Usual actions are: add, remove, change, online,
+ * offline.
+ *
+ * Returns: the kernel action value, or #NULL if there is no action value available.
+ **/
+_public_ const char *udev_device_get_action(struct udev_device *udev_device) {
+        const char *action;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_property_value(udev_device->device, "ACTION", &action);
+        if (r == -ENOENT)
+                return NULL;
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return action;
+}
+
+/**
+ * udev_device_get_usec_since_initialized:
+ * @udev_device: udev device
+ *
+ * Return the number of microseconds passed since udev set up the
+ * device for the first time.
+ *
+ * This is only implemented for devices with need to store properties
+ * in the udev database. All other devices return 0 here.
+ *
+ * Returns: the number of microseconds since the device was first seen.
+ **/
+_public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device) {
+        usec_t ts;
+        int r;
+
+        assert_return(udev_device, -EINVAL);
+
+        r = sd_device_get_usec_since_initialized(udev_device->device, &ts);
+        if (r < 0)
+                return_with_errno(0, r);
+
+        return ts;
+}
+
+/**
+ * udev_device_get_sysattr_value:
+ * @udev_device: udev device
+ * @sysattr: attribute name
+ *
+ * The retrieved value is cached in the device. Repeated calls will return the same
+ * value and not open the attribute again.
+ *
+ * Returns: the content of a sys attribute file, or #NULL if there is no sys attribute value.
+ **/
+_public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr) {
+        const char *value;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_sysattr_value(udev_device->device, sysattr, &value);
+        if (r < 0)
+                return_with_errno(NULL, r);
+
+        return value;
+}
+
+/**
+ * udev_device_set_sysattr_value:
+ * @udev_device: udev device
+ * @sysattr: attribute name
+ * @value: new value to be set
+ *
+ * Update the contents of the sys attribute and the cached value of the device.
+ *
+ * Returns: Negative error code on failure or 0 on success.
+ **/
+_public_ int udev_device_set_sysattr_value(struct udev_device *udev_device, const char *sysattr, const char *value) {
+        int r;
+
+        assert_return(udev_device, -EINVAL);
+
+        r = sd_device_set_sysattr_value(udev_device->device, sysattr, value);
+        if (r < 0)
+                return r;
+
+        return 0;
+}
+
+/**
+ * udev_device_get_sysattr_list_entry:
+ * @udev_device: udev device
+ *
+ * Retrieve the list of available sysattrs, with value being empty;
+ * This just return all available sysfs attributes for a particular
+ * device without reading their values.
+ *
+ * Returns: the first entry of the property list
+ **/
+_public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (!udev_device->sysattrs_read) {
+                const char *sysattr;
+
+                udev_list_cleanup(&udev_device->sysattrs);
+
+                FOREACH_DEVICE_SYSATTR(udev_device->device, sysattr)
+                        if (!udev_list_entry_add(&udev_device->sysattrs, sysattr, NULL))
+                                return_with_errno(NULL, ENOMEM);
+
+                udev_device->sysattrs_read = true;
+        }
+
+        return udev_list_get_entry(&udev_device->sysattrs);
+}
+
+/**
+ * udev_device_get_is_initialized:
+ * @udev_device: udev device
+ *
+ * Check if udev has already handled the device and has set up
+ * device node permissions and context, or has renamed a network
+ * device.
+ *
+ * This is only implemented for devices with a device node
+ * or network interfaces. All other devices return 1 here.
+ *
+ * Returns: 1 if the device is set up. 0 otherwise.
+ **/
+_public_ int udev_device_get_is_initialized(struct udev_device *udev_device) {
+        int r;
+
+        assert_return(udev_device, -EINVAL);
+
+        r = sd_device_get_is_initialized(udev_device->device);
+        if (r < 0)
+                return_with_errno(0, r);
+
+        return r;
+}
+
+/**
+ * udev_device_get_tags_list_entry:
+ * @udev_device: udev device
+ *
+ * Retrieve the list of tags attached to the udev device. The next
+ * list entry can be retrieved with udev_list_entry_get_next(),
+ * which returns #NULL if no more entries exist. The tag string
+ * can be retrieved from the list entry by udev_list_entry_get_name().
+ *
+ * Returns: the first entry of the tag list
+ **/
+_public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device) {
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (device_get_tags_generation(udev_device->device) != udev_device->tags_generation ||
+            !udev_device->tags_read) {
+                const char *tag;
+
+                udev_list_cleanup(&udev_device->tags);
+
+                FOREACH_DEVICE_TAG(udev_device->device, tag)
+                        if (!udev_list_entry_add(&udev_device->tags, tag, NULL))
+                                return_with_errno(NULL, ENOMEM);
+
+                udev_device->tags_read = true;
+                udev_device->tags_generation = device_get_tags_generation(udev_device->device);
+        }
+
+        return udev_list_get_entry(&udev_device->tags);
+}
+
+/**
+ * udev_device_has_tag:
+ * @udev_device: udev device
+ * @tag: tag name
+ *
+ * Check if a given device has a certain tag associated.
+ *
+ * Returns: 1 if the tag is found. 0 otherwise.
+ **/
+_public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag) {
+        assert_return(udev_device, 0);
+
+        return sd_device_has_tag(udev_device->device, tag) > 0;
+}