chiark / gitweb /
libudev: device - replace by a thin wrapper around sd-device
[elogind.git] / src / libudev / libudev-device.c
index 257d6355fed0d5ce54967822a8435c5845196f79..a55cd258f44eba113782aff513e6009e2cf9035e 100644 (file)
@@ -1,13 +1,22 @@
-/*
- * 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.
- */
+/***
+  This file is part of systemd.
+
+  Copyright 2008-2012 Kay Sievers <kay@vrfy.org>
+  Copyright 2015 Tom Gundersen <teg@jklm.no>
+
+  systemd 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.
+
+  systemd is distributed in the hope that it will be useful, but
+  WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public License
+  along with systemd; If not, see <http://www.gnu.org/licenses/>.
+***/
 
 #include <stdio.h>
 #include <stdlib.h>
 #include <sys/socket.h>
 #include <linux/sockios.h>
 
+#include "sd-device.h"
+#include "device-util.h"
+#include "device-private.h"
+
 #include "libudev.h"
 #include "libudev-private.h"
+#include "libudev-device-internal.h"
 
 /**
  * SECTION:libudev-device
  *
  * 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 and have
+ * filesystem. Devices usually belong to a kernel subsystem, and have
  * a unique name inside that subsystem.
  */
 
-/**
- * udev_device:
- *
- * Opaque object representing one kernel sys device.
- */
-struct udev_device {
-        struct udev *udev;
-        struct udev_device *parent_device;
-        char *syspath;
-        const char *devpath;
-        char *sysname;
-        const char *sysnum;
-        char *devnode;
-        mode_t devnode_mode;
-        char *subsystem;
-        char *devtype;
-        char *driver;
-        char *action;
-        char *devpath_old;
-        char *id_filename;
-        char **envp;
-        char *monitor_buf;
-        size_t monitor_buf_len;
-        struct udev_list devlinks_list;
-        struct udev_list properties_list;
-        struct udev_list sysattr_value_list;
-        struct udev_list sysattr_list;
-        struct udev_list tags_list;
-        unsigned long long int seqnum;
-        unsigned long long int usec_initialized;
-        int devlink_priority;
-        int refcount;
-        dev_t devnum;
-        int ifindex;
-        int watch_handle;
-        int maj, min;
-        bool parent_set;
-        bool subsystem_set;
-        bool devtype_set;
-        bool devlinks_uptodate;
-        bool envp_uptodate;
-        bool tags_uptodate;
-        bool driver_set;
-        bool info_loaded;
-        bool db_loaded;
-        bool uevent_loaded;
-        bool is_initialized;
-        bool sysattr_list_read;
-        bool db_persist;
-};
-
 /**
  * udev_device_get_seqnum:
  * @udev_device: udev device
@@ -100,116 +63,75 @@ struct udev_device {
  **/
 _public_ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return 0;
-        return udev_device->seqnum;
-}
-
-static int udev_device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
-{
-        char num[32];
+        const char *seqnum;
+        unsigned long long ret;
+        int r;
 
-        udev_device->seqnum = seqnum;
-        snprintf(num, sizeof(num), "%llu", seqnum);
-        udev_device_add_property(udev_device, "SEQNUM", num);
-        return 0;
-}
+        assert_return_errno(udev_device, 0, EINVAL);
 
-int udev_device_get_ifindex(struct udev_device *udev_device)
-{
-        if (!udev_device->info_loaded)
-                udev_device_read_uevent_file(udev_device);
-        return udev_device->ifindex;
-}
+        r = sd_device_get_property_value(udev_device->device, "SEQNUM", &seqnum);
+        if (r == -ENOENT)
+                return 0;
+        else if (r < 0) {
+                errno = -r;
+                return 0;
+        }
 
-static int udev_device_set_ifindex(struct udev_device *udev_device, int ifindex)
-{
-        char num[32];
+        r = safe_atollu(seqnum, &ret);
+        if (r < 0) {
+                errno = -r;
+                return 0;
+        }
 
-        udev_device->ifindex = ifindex;
-        snprintf(num, sizeof(num), "%u", ifindex);
-        udev_device_add_property(udev_device, "IFINDEX", num);
-        return 0;
+        return ret;
 }
 
 /**
  * udev_device_get_devnum:
  * @udev_device: udev device
  *
- * Returns: the device major/minor number.
+ * Get the device major/minor number.
+ *
+ * Returns: the dev_t number.
  **/
 _public_ dev_t udev_device_get_devnum(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return makedev(0, 0);
-        if (!udev_device->info_loaded)
-                udev_device_read_uevent_file(udev_device);
-        return udev_device->devnum;
-}
-
-static int udev_device_set_devnum(struct udev_device *udev_device, dev_t devnum)
-{
-        char num[32];
-
-        udev_device->devnum = devnum;
-
-        snprintf(num, sizeof(num), "%u", major(devnum));
-        udev_device_add_property(udev_device, "MAJOR", num);
-        snprintf(num, sizeof(num), "%u", minor(devnum));
-        udev_device_add_property(udev_device, "MINOR", num);
-        return 0;
-}
-
-const char *udev_device_get_devpath_old(struct udev_device *udev_device)
-{
-        return udev_device->devpath_old;
-}
+        dev_t devnum;
+        int r;
 
-static int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
-{
-        const char *pos;
+        assert_return_errno(udev_device, makedev(0, 0), EINVAL);
 
-        free(udev_device->devpath_old);
-        udev_device->devpath_old = strdup(devpath_old);
-        if (udev_device->devpath_old == NULL)
-                return -ENOMEM;
-        udev_device_add_property(udev_device, "DEVPATH_OLD", udev_device->devpath_old);
+        r = sd_device_get_devnum(udev_device->device, &devnum);
+        if (r < 0) {
+                errno = -r;
+                return makedev(0, 0);
+        }
 
-        pos = strrchr(udev_device->devpath_old, '/');
-        if (pos == NULL)
-                return -EINVAL;
-        return 0;
+        return devnum;
 }
 
 /**
  * udev_device_get_driver:
  * @udev_device: udev device
  *
- * Returns: the driver string, or #NULL if there is no driver attached.
+ * 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)
 {
-        char driver[UTIL_NAME_SIZE];
+        const char *driver;
+        int r;
 
-        if (udev_device == NULL)
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_driver(udev_device->device, &driver);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        if (!udev_device->driver_set) {
-                udev_device->driver_set = true;
-                if (util_get_sys_core_link_value(udev_device->udev, "driver", udev_device->syspath, driver, sizeof(driver)) > 0)
-                        udev_device->driver = strdup(driver);
         }
-        return udev_device->driver;
-}
 
-static int udev_device_set_driver(struct udev_device *udev_device, const char *driver)
-{
-        free(udev_device->driver);
-        udev_device->driver = strdup(driver);
-        if (udev_device->driver == NULL)
-                return -ENOMEM;
-        udev_device->driver_set = true;
-        udev_device_add_property(udev_device, "DRIVER", udev_device->driver);
-        return 0;
+        return driver;
 }
 
 /**
@@ -222,35 +144,18 @@ static int udev_device_set_driver(struct udev_device *udev_device, const char *d
  **/
 _public_ const char *udev_device_get_devtype(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
+        const char *devtype;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devtype(udev_device->device, &devtype);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        if (!udev_device->devtype_set) {
-                udev_device->devtype_set = true;
-                udev_device_read_uevent_file(udev_device);
         }
-        return udev_device->devtype;
-}
-
-static int udev_device_set_devtype(struct udev_device *udev_device, const char *devtype)
-{
-        free(udev_device->devtype);
-        udev_device->devtype = strdup(devtype);
-        if (udev_device->devtype == NULL)
-                return -ENOMEM;
-        udev_device->devtype_set = true;
-        udev_device_add_property(udev_device, "DEVTYPE", udev_device->devtype);
-        return 0;
-}
 
-static int udev_device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
-{
-        free(udev_device->subsystem);
-        udev_device->subsystem = strdup(subsystem);
-        if (udev_device->subsystem == NULL)
-                return -ENOMEM;
-        udev_device->subsystem_set = true;
-        udev_device_add_property(udev_device, "SUBSYSTEM", udev_device->subsystem);
-        return 0;
+        return devtype;
 }
 
 /**
@@ -264,175 +169,18 @@ static int udev_device_set_subsystem(struct udev_device *udev_device, const char
  **/
 _public_ const char *udev_device_get_subsystem(struct udev_device *udev_device)
 {
-        char subsystem[UTIL_NAME_SIZE];
-
-        if (udev_device == NULL)
-                return NULL;
-        if (!udev_device->subsystem_set) {
-                udev_device->subsystem_set = true;
-                /* read "subsystem" link */
-                if (util_get_sys_core_link_value(udev_device->udev, "subsystem", udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
-                        udev_device_set_subsystem(udev_device, subsystem);
-                        return udev_device->subsystem;
-                }
-                /* implicit names */
-                if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
-                        udev_device_set_subsystem(udev_device, "module");
-                        return udev_device->subsystem;
-                }
-                if (strstr(udev_device->devpath, "/drivers/") != NULL) {
-                        udev_device_set_subsystem(udev_device, "drivers");
-                        return udev_device->subsystem;
-                }
-                if (strncmp(udev_device->devpath, "/subsystem/", 11) == 0 ||
-                    strncmp(udev_device->devpath, "/class/", 7) == 0 ||
-                    strncmp(udev_device->devpath, "/bus/", 5) == 0) {
-                        udev_device_set_subsystem(udev_device, "subsystem");
-                        return udev_device->subsystem;
-                }
-        }
-        return udev_device->subsystem;
-}
-
-mode_t udev_device_get_devnode_mode(struct udev_device *udev_device)
-{
-        if (!udev_device->info_loaded)
-                udev_device_read_uevent_file(udev_device);
-        return udev_device->devnode_mode;
-}
+        const char *subsystem;
+        int r;
 
-static int udev_device_set_devnode_mode(struct udev_device *udev_device, mode_t mode)
-{
-        char num[32];
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-        udev_device->devnode_mode = mode;
-        snprintf(num, sizeof(num), "%#o", mode);
-        udev_device_add_property(udev_device, "DEVMODE", num);
-        return 0;
-}
-
-struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value)
-{
-        udev_device->envp_uptodate = false;
-        if (value == NULL) {
-                struct udev_list_entry *list_entry;
-
-                list_entry = udev_device_get_properties_list_entry(udev_device);
-                list_entry = udev_list_entry_get_by_name(list_entry, key);
-                if (list_entry != NULL)
-                        udev_list_entry_delete(list_entry);
+        r = sd_device_get_subsystem(udev_device->device, &subsystem);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
         }
-        return udev_list_entry_add(&udev_device->properties_list, key, value);
-}
 
-static struct udev_list_entry *udev_device_add_property_from_string(struct udev_device *udev_device, const char *property)
-{
-        char name[UTIL_LINE_SIZE];
-        char *val;
-
-        util_strscpy(name, sizeof(name), property);
-        val = strchr(name, '=');
-        if (val == NULL)
-                return NULL;
-        val[0] = '\0';
-        val = &val[1];
-        if (val[0] == '\0')
-                val = NULL;
-        return udev_device_add_property(udev_device, name, val);
-}
-
-/*
- * parse property string, and if needed, update internal values accordingly
- *
- * udev_device_add_property_from_string_parse_finish() needs to be
- * called after adding properties, and its return value checked
- *
- * udev_device_set_info_loaded() needs to be set, to avoid trying
- * to use a device without a DEVPATH set
- */
-void udev_device_add_property_from_string_parse(struct udev_device *udev_device, const char *property)
-{
-        if (strncmp(property, "DEVPATH=", 8) == 0) {
-                char path[UTIL_PATH_SIZE];
-
-                util_strscpyl(path, sizeof(path), udev_get_sys_path(udev_device->udev), &property[8], NULL);
-                udev_device_set_syspath(udev_device, path);
-        } else if (strncmp(property, "SUBSYSTEM=", 10) == 0) {
-                udev_device_set_subsystem(udev_device, &property[10]);
-        } else if (strncmp(property, "DEVTYPE=", 8) == 0) {
-                udev_device_set_devtype(udev_device, &property[8]);
-        } else if (strncmp(property, "DEVNAME=", 8) == 0) {
-                udev_device_set_devnode(udev_device, &property[8]);
-        } else if (strncmp(property, "DEVLINKS=", 9) == 0) {
-                char devlinks[UTIL_PATH_SIZE];
-                char *slink;
-                char *next;
-
-                util_strscpy(devlinks, sizeof(devlinks), &property[9]);
-                slink = devlinks;
-                next = strchr(slink, ' ');
-                while (next != NULL) {
-                        next[0] = '\0';
-                        udev_device_add_devlink(udev_device, slink, 0);
-                        slink = &next[1];
-                        next = strchr(slink, ' ');
-                }
-                if (slink[0] != '\0')
-                        udev_device_add_devlink(udev_device, slink, 0);
-        } else if (strncmp(property, "TAGS=", 5) == 0) {
-                char tags[UTIL_PATH_SIZE];
-                char *next;
-
-                util_strscpy(tags, sizeof(tags), &property[5]);
-                next = strchr(tags, ':');
-                if (next != NULL) {
-                        next++;
-                        while (next[0] != '\0') {
-                                char *tag;
-
-                                tag = next;
-                                next = strchr(tag, ':');
-                                if (next == NULL)
-                                        break;
-                                next[0] = '\0';
-                                next++;
-                                udev_device_add_tag(udev_device, tag);
-                        }
-                }
-        } else if (strncmp(property, "USEC_INITIALIZED=", 19) == 0) {
-                udev_device_set_usec_initialized(udev_device, strtoull(&property[19], NULL, 10));
-        } else if (strncmp(property, "DRIVER=", 7) == 0) {
-                udev_device_set_driver(udev_device, &property[7]);
-        } else if (strncmp(property, "ACTION=", 7) == 0) {
-                udev_device_set_action(udev_device, &property[7]);
-        } else if (strncmp(property, "MAJOR=", 6) == 0) {
-                udev_device->maj = strtoull(&property[6], NULL, 10);
-        } else if (strncmp(property, "MINOR=", 6) == 0) {
-                udev_device->min = strtoull(&property[6], NULL, 10);
-        } else if (strncmp(property, "DEVPATH_OLD=", 12) == 0) {
-                udev_device_set_devpath_old(udev_device, &property[12]);
-        } else if (strncmp(property, "SEQNUM=", 7) == 0) {
-                udev_device_set_seqnum(udev_device, strtoull(&property[7], NULL, 10));
-        } else if (strncmp(property, "IFINDEX=", 8) == 0) {
-                udev_device_set_ifindex(udev_device, strtoull(&property[8], NULL, 10));
-        } else if (strncmp(property, "DEVMODE=", 8) == 0) {
-                udev_device_set_devnode_mode(udev_device, strtoul(&property[8], NULL, 8));
-        } else {
-                udev_device_add_property_from_string(udev_device, property);
-        }
-}
-
-int udev_device_add_property_from_string_parse_finish(struct udev_device *udev_device)
-{
-        if (udev_device->maj > 0)
-                udev_device_set_devnum(udev_device, makedev(udev_device->maj, udev_device->min));
-        udev_device->maj = 0;
-        udev_device->min = 0;
-
-        if (udev_device->devpath == NULL || udev_device->subsystem == NULL)
-                return -EINVAL;
-        return 0;
+        return subsystem;
 }
 
 /**
@@ -440,171 +188,43 @@ int udev_device_add_property_from_string_parse_finish(struct udev_device *udev_d
  * @udev_device: udev device
  * @key: property name
  *
- * Returns: the value of a device property, or #NULL if there is no such property.
+ * 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)
 {
-        struct udev_list_entry *list_entry;
-
-        if (udev_device == NULL)
-                return NULL;
-        if (key == NULL)
-                return NULL;
-
-        list_entry = udev_device_get_properties_list_entry(udev_device);
-        list_entry = udev_list_entry_get_by_name(list_entry, key);
-        return udev_list_entry_get_value(list_entry);
-}
-
-int udev_device_read_db(struct udev_device *udev_device, const char *dbfile)
-{
-        char filename[UTIL_PATH_SIZE];
-        char line[UTIL_LINE_SIZE];
-        FILE *f;
-
-        /* providing a database file will always force-load it */
-        if (dbfile == NULL) {
-                const char *id;
-
-                if (udev_device->db_loaded)
-                        return 0;
-                udev_device->db_loaded = true;
-
-                id = udev_device_get_id_filename(udev_device);
-                if (id == NULL)
-                        return -1;
-                util_strscpyl(filename, sizeof(filename), udev_get_run_path(udev_device->udev), "/data/", id, NULL);
-                dbfile = filename;
-        }
-
-        f = fopen(dbfile, "re");
-        if (f == NULL) {
-                dbg(udev_device->udev, "no db file to read %s: %m\n", dbfile);
-                return -1;
-        }
-        udev_device->is_initialized = true;
-
-        while (fgets(line, sizeof(line), f)) {
-                ssize_t len;
-                const char *val;
-                struct udev_list_entry *entry;
-
-                len = strlen(line);
-                if (len < 4)
-                        break;
-                line[len-1] = '\0';
-                val = &line[2];
-                switch(line[0]) {
-                case 'S':
-                        util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/", val, NULL);
-                        udev_device_add_devlink(udev_device, filename, 0);
-                        break;
-                case 'L':
-                        udev_device_set_devlink_priority(udev_device, atoi(val));
-                        break;
-                case 'E':
-                        entry = udev_device_add_property_from_string(udev_device, val);
-                        udev_list_entry_set_num(entry, true);
-                        break;
-                case 'G':
-                        udev_device_add_tag(udev_device, val);
-                        break;
-                case 'W':
-                        udev_device_set_watch_handle(udev_device, atoi(val));
-                        break;
-                case 'I':
-                        udev_device_set_usec_initialized(udev_device, strtoull(val, NULL, 10));
-                        break;
-                }
-        }
-        fclose(f);
-
-        dbg(udev_device->udev, "device %p filled with db file data\n", udev_device);
-        return 0;
-}
-
-int udev_device_read_uevent_file(struct udev_device *udev_device)
-{
-        char filename[UTIL_PATH_SIZE];
-        FILE *f;
-        char line[UTIL_LINE_SIZE];
-        int maj = 0;
-        int min = 0;
+        const char *value = NULL;
+        int r;
 
-        if (udev_device->uevent_loaded)
-                return 0;
+        assert_return_errno(udev_device && key, NULL, EINVAL);
 
-        util_strscpyl(filename, sizeof(filename), udev_device->syspath, "/uevent", NULL);
-        f = fopen(filename, "re");
-        if (f == NULL)
-                return -1;
-        udev_device->uevent_loaded = true;
-
-        while (fgets(line, sizeof(line), f)) {
-                char *pos;
-
-                pos = strchr(line, '\n');
-                if (pos == NULL)
-                        continue;
-                pos[0] = '\0';
-
-                if (strncmp(line, "DEVTYPE=", 8) == 0) {
-                        udev_device_set_devtype(udev_device, &line[8]);
-                        continue;
-                }
-                if (strncmp(line, "IFINDEX=", 8) == 0) {
-                        udev_device_set_ifindex(udev_device, strtoull(&line[8], NULL, 10));
-                        continue;
-                }
-                if (strncmp(line, "DEVNAME=", 8) == 0) {
-                        udev_device_set_devnode(udev_device, &line[8]);
-                        continue;
-                }
-
-                if (strncmp(line, "MAJOR=", 6) == 0)
-                        maj = strtoull(&line[6], NULL, 10);
-                else if (strncmp(line, "MINOR=", 6) == 0)
-                        min = strtoull(&line[6], NULL, 10);
-                else if (strncmp(line, "DEVMODE=", 8) == 0)
-                        udev_device->devnode_mode = strtoul(&line[8], NULL, 8);
-
-                udev_device_add_property_from_string(udev_device, line);
+        r = sd_device_get_property_value(udev_device->device, key, &value);
+        if (r < 0) {
+                errno = -r;
+                return NULL;
         }
 
-        udev_device->devnum = makedev(maj, min);
-        fclose(f);
-        return 0;
+        return value;
 }
 
-void udev_device_set_info_loaded(struct udev_device *device)
-{
-        device->info_loaded = true;
-}
-
-struct udev_device *udev_device_new(struct udev *udev)
-{
+struct udev_device *udev_device_new(struct udev *udev) {
         struct udev_device *udev_device;
-        struct udev_list_entry *list_entry;
 
-        if (udev == NULL)
-                return NULL;
+        assert_return_errno(udev, NULL, EINVAL);
 
-        udev_device = calloc(1, sizeof(struct udev_device));
-        if (udev_device == NULL)
+        udev_device = new0(struct udev_device, 1);
+        if (!udev_device) {
+                errno = ENOMEM;
                 return NULL;
+        }
         udev_device->refcount = 1;
         udev_device->udev = udev;
-        udev_list_init(udev, &udev_device->devlinks_list, true);
-        udev_list_init(udev, &udev_device->properties_list, true);
-        udev_list_init(udev, &udev_device->sysattr_value_list, true);
-        udev_list_init(udev, &udev_device->sysattr_list, false);
-        udev_list_init(udev, &udev_device->tags_list, true);
-        udev_device->watch_handle = -1;
-        /* copy global properties */
-        udev_list_entry_foreach(list_entry, udev_get_properties_list_entry(udev))
-                udev_device_add_property(udev_device,
-                                         udev_list_entry_get_name(list_entry),
-                                         udev_list_entry_get_value(list_entry));
+        udev_list_init(udev, &udev_device->properties, true);
+        udev_list_init(udev, &udev_device->tags, true);
+        udev_list_init(udev, &udev_device->sysattrs, true);
+        udev_list_init(udev, &udev_device->devlinks, true);
+
         return udev_device;
 }
 
@@ -622,57 +242,21 @@ struct udev_device *udev_device_new(struct udev *udev)
  *
  * 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)
-{
-        size_t len;
-        const char *subdir;
-        char path[UTIL_PATH_SIZE];
-        char *pos;
-        struct stat statbuf;
+_public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath) {
         struct udev_device *udev_device;
+        int r;
 
-        if (udev == NULL)
-                return NULL;
-        if (syspath == NULL)
-                return NULL;
-
-        /* path starts in sys */
-        len = strlen(udev_get_sys_path(udev));
-        if (strncmp(syspath, udev_get_sys_path(udev), len) != 0) {
-                dbg(udev, "not in sys :%s\n", syspath);
+        udev_device = udev_device_new(udev);
+        if (!udev_device)
                 return NULL;
-        }
 
-        /* path is not a root directory */
-        subdir = &syspath[len+1];
-        pos = strrchr(subdir, '/');
-        if (pos == NULL || pos[1] == '\0' || pos < &subdir[2])
+        r = sd_device_new_from_syspath(&udev_device->device, syspath);
+        if (r < 0) {
+                errno = -r;
+                udev_device_unref(udev_device);
                 return NULL;
-
-        /* resolve possible symlink to real path */
-        util_strscpy(path, sizeof(path), syspath);
-        util_resolve_sys_link(udev, path, sizeof(path));
-
-        if (strncmp(&path[len], "/devices/", 9) == 0) {
-                char file[UTIL_PATH_SIZE];
-
-                /* all "devices" require a "uevent" file */
-                util_strscpyl(file, sizeof(file), path, "/uevent", NULL);
-                if (stat(file, &statbuf) != 0)
-                        return NULL;
-        } else {
-                /* everything else just needs to be a directory */
-                if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode))
-                        return NULL;
         }
 
-        udev_device = udev_device_new(udev);
-        if (udev_device == NULL)
-                return NULL;
-
-        udev_device_set_syspath(udev_device, path);
-        dbg(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
-
         return udev_device;
 }
 
@@ -694,75 +278,58 @@ _public_ struct udev_device *udev_device_new_from_syspath(struct udev *udev, con
  **/
 _public_ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, dev_t devnum)
 {
-        char path[UTIL_PATH_SIZE];
-        const char *type_str;
-
-        if (type == 'b')
-                type_str = "block";
-        else if (type == 'c')
-                type_str = "char";
-        else
+        struct udev_device *udev_device;
+        int r;
+
+        udev_device = udev_device_new(udev);
+        if (!udev_device)
                 return NULL;
 
-        /* use /sys/dev/{block,char}/<maj>:<min> link */
-        snprintf(path, sizeof(path), "%s/dev/%s/%u:%u",
-                 udev_get_sys_path(udev), type_str, major(devnum), minor(devnum));
-        return udev_device_new_from_syspath(udev, path);
+        r = sd_device_new_from_devnum(&udev_device->device, type, devnum);
+        if (r < 0) {
+                errno = -r;
+                udev_device_unref(udev_device);
+                return NULL;
+        }
+
+        return udev_device;
 }
 
-struct udev_device *udev_device_new_from_id_filename(struct udev *udev, char *id)
+/**
+ * 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)
 {
-        char type;
-        int maj, min;
-        char subsys[UTIL_PATH_SIZE];
-        char *sysname;
-
-        switch(id[0]) {
-        case 'b':
-        case 'c':
-                if (sscanf(id, "%c%i:%i", &type, &maj, &min) != 3)
-                        return NULL;
-                return udev_device_new_from_devnum(udev, type, makedev(maj, min));
-        case 'n': {
-                int sk;
-                struct ifreq ifr;
-                struct udev_device *dev;
-                int ifindex;
-
-                ifindex = strtoul(&id[1], NULL, 10);
-                if (ifindex <= 0)
-                        return NULL;
-
-                sk = socket(PF_INET, SOCK_DGRAM, 0);
-                if (sk < 0)
-                        return NULL;
-                memset(&ifr, 0x00, sizeof(struct ifreq));
-                ifr.ifr_ifindex = ifindex;
-                if (ioctl(sk, SIOCGIFNAME, &ifr) != 0) {
-                        close(sk);
-                        return NULL;
-                }
-                close(sk);
-
-                dev = udev_device_new_from_subsystem_sysname(udev, "net", ifr.ifr_name);
-                if (dev == NULL)
-                        return NULL;
-                if (udev_device_get_ifindex(dev) == ifindex)
-                        return dev;
-                udev_device_unref(dev);
+        struct udev_device *udev_device;
+        int r;
+
+        udev_device = udev_device_new(udev);
+        if (!udev_device)
                 return NULL;
-        }
-        case '+':
-                util_strscpy(subsys, sizeof(subsys), &id[1]);
-                sysname = strchr(subsys, ':');
-                if (sysname == NULL)
-                        return NULL;
-                sysname[0] = '\0';
-                sysname = &sysname[1];
-                return udev_device_new_from_subsystem_sysname(udev, subsys, sysname);
-        default:
+
+        r = sd_device_new_from_device_id(&udev_device->device, id);
+        if (r < 0) {
+                errno = -r;
+                udev_device_unref(udev_device);
                 return NULL;
         }
+
+        return udev_device;
 }
 
 /**
@@ -782,72 +349,21 @@ struct udev_device *udev_device_new_from_id_filename(struct udev *udev, char *id
  **/
 _public_ struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 {
-        char path_full[UTIL_PATH_SIZE];
-        char *path;
-        size_t l;
-        struct stat statbuf;
-
-        path = path_full;
-        l = util_strpcpyl(&path, sizeof(path_full), udev_get_sys_path(udev), NULL);
-
-        if (strcmp(subsystem, "subsystem") == 0) {
-                util_strscpyl(path, l, "/subsystem/", sysname, NULL);
-                if (stat(path_full, &statbuf) == 0)
-                        goto found;
-
-                util_strscpyl(path, l, "/bus/", sysname, NULL);
-                if (stat(path_full, &statbuf) == 0)
-                        goto found;
-
-                util_strscpyl(path, l, "/class/", sysname, NULL);
-                if (stat(path_full, &statbuf) == 0)
-                        goto found;
-                goto out;
-        }
+        struct udev_device *udev_device;
+        int r;
 
-        if (strcmp(subsystem, "module") == 0) {
-                util_strscpyl(path, l, "/module/", sysname, NULL);
-                if (stat(path_full, &statbuf) == 0)
-                        goto found;
-                goto out;
-        }
+        udev_device = udev_device_new(udev);
+        if (!udev_device)
+                return NULL;
 
-        if (strcmp(subsystem, "drivers") == 0) {
-                char subsys[UTIL_NAME_SIZE];
-                char *driver;
-
-                util_strscpy(subsys, sizeof(subsys), sysname);
-                driver = strchr(subsys, ':');
-                if (driver != NULL) {
-                        driver[0] = '\0';
-                        driver = &driver[1];
-
-                        util_strscpyl(path, l, "/subsystem/", subsys, "/drivers/", driver, NULL);
-                        if (stat(path_full, &statbuf) == 0)
-                                goto found;
-
-                        util_strscpyl(path, l, "/bus/", subsys, "/drivers/", driver, NULL);
-                        if (stat(path_full, &statbuf) == 0)
-                                goto found;
-                }
-                goto out;
+        r = sd_device_new_from_subsystem_sysname(&udev_device->device, subsystem, sysname);
+        if (r < 0) {
+                errno = -r;
+                udev_device_unref(udev_device);
+                return NULL;
         }
 
-        util_strscpyl(path, l, "/subsystem/", subsystem, "/devices/", sysname, NULL);
-        if (stat(path_full, &statbuf) == 0)
-                goto found;
-
-        util_strscpyl(path, l, "/bus/", subsystem, "/devices/", sysname, NULL);
-        if (stat(path_full, &statbuf) == 0)
-                goto found;
-
-        util_strscpyl(path, l, "/class/", subsystem, "/", sysname, NULL);
-        if (stat(path_full, &statbuf) == 0)
-                goto found;
-out:
-        return NULL;
-found:
-        return udev_device_new_from_syspath(udev, path_full);
+        return udev_device;
 }
 
 /**
@@ -866,46 +382,45 @@ found:
  **/
 _public_ struct udev_device *udev_device_new_from_environment(struct udev *udev)
 {
-        int i;
         struct udev_device *udev_device;
+        int r;
 
         udev_device = udev_device_new(udev);
-        if (udev_device == NULL)
+        if (!udev_device)
                 return NULL;
-        udev_device_set_info_loaded(udev_device);
-
-        for (i = 0; environ[i] != NULL; i++)
-                udev_device_add_property_from_string_parse(udev_device, environ[i]);
 
-        if (udev_device_add_property_from_string_parse_finish(udev_device) < 0) {
-                dbg(udev, "missing values, invalid device\n");
+        r = device_new_from_strv(&udev_device->device, environ);
+        if (r < 0) {
+                errno = -r;
                 udev_device_unref(udev_device);
-                udev_device = NULL;
+                return NULL;
         }
 
         return udev_device;
 }
 
-static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
+static struct udev_device *device_new_from_parent(struct udev_device *child)
 {
-        struct udev_device *udev_device_parent = NULL;
-        char path[UTIL_PATH_SIZE];
-        const char *subdir;
-
-        util_strscpy(path, sizeof(path), udev_device->syspath);
-        subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
-        for (;;) {
-                char *pos;
-
-                pos = strrchr(subdir, '/');
-                if (pos == NULL || pos < &subdir[2])
-                        break;
-                pos[0] = '\0';
-                udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
-                if (udev_device_parent != NULL)
-                        return udev_device_parent;
+        struct udev_device *parent;
+        int r;
+
+        assert_return_errno(child, NULL, EINVAL);
+
+        parent = udev_device_new(child->udev);
+        if (!parent)
+                return NULL;
+
+        r = sd_device_get_parent(child->device, &parent->device);
+        if (r < 0) {
+                errno = -r;
+                udev_device_unref(parent);
+                return NULL;
         }
-        return NULL;
+
+        /* the parent is unref'ed with the child, so take a ref from libudev as well */
+        sd_device_ref(parent->device);
+
+        return parent;
 }
 
 /**
@@ -915,9 +430,8 @@ static struct udev_device *device_new_from_parent(struct udev_device *udev_devic
  * Find the next parent device, and fill in information from the sys
  * device and the udev database entry.
  *
- * The returned the device is not referenced. It is attached to the
- * child device, and will be cleaned up when the child device
- * is cleaned up.
+ * 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.
@@ -929,13 +443,15 @@ static struct udev_device *device_new_from_parent(struct udev_device *udev_devic
  **/
 _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
+        assert_return_errno(udev_device, NULL, EINVAL);
+
         if (!udev_device->parent_set) {
                 udev_device->parent_set = true;
-                udev_device->parent_device = device_new_from_parent(udev_device);
+                udev_device->parent = device_new_from_parent(udev_device);
         }
-        return udev_device->parent_device;
+
+        /* TODO: errno will differ here in case parent == NULL */
+        return udev_device->parent;
 }
 
 /**
@@ -951,9 +467,8 @@ _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_dev
  * If devtype is #NULL, only subsystem is checked, and any devtype will
  * match.
  *
- * The returned the device is not referenced. It is attached to the
- * child device, and will be cleaned up when the child device
- * is cleaned up.
+ * 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.
@@ -962,27 +477,30 @@ _public_ struct udev_device *udev_device_get_parent(struct udev_device *udev_dev
  **/
 _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struct udev_device *udev_device, const char *subsystem, const char *devtype)
 {
-        struct udev_device *parent;
+        sd_device *parent;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-        if (subsystem == NULL)
+        /* 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) {
+                errno = -r;
                 return NULL;
+        }
 
-        parent = udev_device_get_parent(udev_device);
-        while (parent != NULL) {
-                const char *parent_subsystem;
-                const char *parent_devtype;
-
-                parent_subsystem = udev_device_get_subsystem(parent);
-                if (parent_subsystem != NULL && strcmp(parent_subsystem, subsystem) == 0) {
-                        if (devtype == NULL)
-                                break;
-                        parent_devtype = udev_device_get_devtype(parent);
-                        if (parent_devtype != NULL && strcmp(parent_devtype, devtype) == 0)
-                                break;
-                }
-                parent = udev_device_get_parent(parent);
+        /* then walk the chain of udev_device parents until the correspanding
+           one is found */
+        while ((udev_device = udev_device_get_parent(udev_device))) {
+                if (udev_device->device == parent)
+                        return udev_device;
         }
-        return parent;
+
+        errno = ENOENT;
+        return NULL;
 }
 
 /**
@@ -995,8 +513,8 @@ _public_ struct udev_device *udev_device_get_parent_with_subsystem_devtype(struc
  **/
 _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
+        assert_return_errno(udev_device, NULL, EINVAL);
+
         return udev_device->udev;
 }
 
@@ -1010,9 +528,9 @@ _public_ struct udev *udev_device_get_udev(struct udev_device *udev_device)
  **/
 _public_ struct udev_device *udev_device_ref(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
-        udev_device->refcount++;
+        if (udev_device)
+                udev_device->refcount++;
+
         return udev_device;
 }
 
@@ -1023,33 +541,23 @@ _public_ struct udev_device *udev_device_ref(struct 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
  **/
-_public_ void udev_device_unref(struct udev_device *udev_device)
+_public_ struct udev_device *udev_device_unref(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return;
-        udev_device->refcount--;
-        if (udev_device->refcount > 0)
-                return;
-        if (udev_device->parent_device != NULL)
-                udev_device_unref(udev_device->parent_device);
-        free(udev_device->syspath);
-        free(udev_device->sysname);
-        free(udev_device->devnode);
-        free(udev_device->subsystem);
-        free(udev_device->devtype);
-        udev_list_cleanup(&udev_device->devlinks_list);
-        udev_list_cleanup(&udev_device->properties_list);
-        udev_list_cleanup(&udev_device->sysattr_value_list);
-        udev_list_cleanup(&udev_device->sysattr_list);
-        udev_list_cleanup(&udev_device->tags_list);
-        free(udev_device->action);
-        free(udev_device->driver);
-        free(udev_device->devpath_old);
-        free(udev_device->id_filename);
-        free(udev_device->envp);
-        free(udev_device->monitor_buf);
-        free(udev_device);
+        if (udev_device && (-- udev_device->refcount) == 0) {
+                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);
+
+                free(udev_device);
+        }
+
+        return NULL;
 }
 
 /**
@@ -1063,9 +571,18 @@ _public_ void udev_device_unref(struct udev_device *udev_device)
  **/
 _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
+        const char *devpath;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devpath(udev_device->device, &devpath);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        return udev_device->devpath;
+        }
+
+        return devpath;
 }
 
 /**
@@ -1079,35 +596,66 @@ _public_ const char *udev_device_get_devpath(struct udev_device *udev_device)
  **/
 _public_ const char *udev_device_get_syspath(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
+        const char *syspath;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_syspath(udev_device->device, &syspath);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        return udev_device->syspath;
+        }
+
+        return syspath;
 }
 
 /**
  * udev_device_get_sysname:
  * @udev_device: udev device
  *
- * Returns: the sys name of the device device
+ * Get the kernel device name in /sys.
+ *
+ * Returns: the name string of the device device
  **/
 _public_ const char *udev_device_get_sysname(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
+        const char *sysname;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_sysname(udev_device->device, &sysname);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        return udev_device->sysname;
+        }
+
+        return sysname;
 }
 
 /**
  * udev_device_get_sysnum:
  * @udev_device: udev device
  *
- * Returns: the trailing number of of the device name
+ * 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)
 {
-        if (udev_device == NULL)
+        const char *sysnum;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_sysnum(udev_device->device, &sysnum);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        return udev_device->sysnum;
+        }
+
+        return sysnum;
 }
 
 /**
@@ -1121,13 +669,18 @@ _public_ const char *udev_device_get_sysnum(struct udev_device *udev_device)
  **/
 _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
+        const char *devnode;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_devname(udev_device->device, &devnode);
+        if (r < 0) {
+                errno = -r;
                 return NULL;
-        if (udev_device->devnode != NULL)
-                return udev_device->devnode;
-        if (!udev_device->info_loaded)
-                udev_device_read_uevent_file(udev_device);
-        return udev_device->devnode;
+        }
+
+        return devnode;
 }
 
 /**
@@ -1145,21 +698,24 @@ _public_ const char *udev_device_get_devnode(struct udev_device *udev_device)
  **/
 _public_ struct udev_list_entry *udev_device_get_devlinks_list_entry(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        return udev_list_get_entry(&udev_device->devlinks_list);
-}
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
-{
-        udev_device->devlinks_uptodate = false;
-        udev_list_cleanup(&udev_device->devlinks_list);
+        if (device_get_devlinks_generation(udev_device->device) != udev_device->devlinks_generation) {
+                const char *devlink;
+
+                udev_list_cleanup(&udev_device->devlinks);
+
+                FOREACH_DEVICE_DEVLINK(udev_device->device, devlink)
+                        udev_list_entry_add(&udev_device->devlinks, devlink, NULL);
+
+                udev_device->devlinks_generation = device_get_devlinks_generation(udev_device->device);
+        }
+
+        return udev_list_get_entry(&udev_device->devlinks);
 }
 
 /**
- * udev_device_get_properties_list_entry:
+ * udev_device_get_event_properties_entry:
  * @udev_device: udev device
  *
  * Retrieve the list of key/value device properties of the udev
@@ -1172,45 +728,20 @@ void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
  **/
 _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
-        if (!udev_device->info_loaded) {
-                udev_device_read_uevent_file(udev_device);
-                udev_device_read_db(udev_device, NULL);
-        }
-        if (!udev_device->devlinks_uptodate) {
-                char symlinks[UTIL_PATH_SIZE];
-                struct udev_list_entry *list_entry;
-
-                udev_device->devlinks_uptodate = true;
-                list_entry = udev_device_get_devlinks_list_entry(udev_device);
-                if (list_entry != NULL) {
-                        char *s;
-                        size_t l;
-
-                        s = symlinks;
-                        l = util_strpcpyl(&s, sizeof(symlinks), udev_list_entry_get_name(list_entry), NULL);
-                        udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
-                                l = util_strpcpyl(&s, l, " ", udev_list_entry_get_name(list_entry), NULL);
-                        udev_device_add_property(udev_device, "DEVLINKS", symlinks);
-                }
-        }
-        if (!udev_device->tags_uptodate) {
-                udev_device->tags_uptodate = true;
-                if (udev_device_get_tags_list_entry(udev_device) != NULL) {
-                        char tags[UTIL_PATH_SIZE];
-                        struct udev_list_entry *list_entry;
-                        char *s;
-                        size_t l;
-
-                        s = tags;
-                        l = util_strpcpyl(&s, sizeof(tags), ":", NULL);
-                        udev_list_entry_foreach(list_entry, udev_device_get_tags_list_entry(udev_device))
-                                l = util_strpcpyl(&s, l, udev_list_entry_get_name(list_entry), ":", NULL);
-                        udev_device_add_property(udev_device, "TAGS", tags);
-                }
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        if (device_get_properties_generation(udev_device->device) != udev_device->properties_generation) {
+                const char *key, *value;
+
+                udev_list_cleanup(&udev_device->properties);
+
+                FOREACH_DEVICE_PROPERTY(udev_device->device, key, value)
+                        udev_list_entry_add(&udev_device->properties, key, value);
+
+                udev_device->properties_generation = device_get_properties_generation(udev_device->device);
         }
-        return udev_list_get_entry(&udev_device->properties_list);
+
+        return udev_list_get_entry(&udev_device->properties);
 }
 
 /**
@@ -1223,11 +754,19 @@ _public_ struct udev_list_entry *udev_device_get_properties_list_entry(struct ud
  *
  * 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)
-{
-        if (udev_device == NULL)
+_public_ const char *udev_device_get_action(struct udev_device *udev_device) {
+        const char *action = NULL;
+        int r;
+
+        assert_return_errno(udev_device, NULL, EINVAL);
+
+        r = sd_device_get_property_value(udev_device->device, "ACTION", &action);
+        if (r < 0 && r != -ENOENT) {
+                errno = -r;
                 return NULL;
-        return udev_device->action;
+        }
+
+        return action;
 }
 
 /**
@@ -1244,32 +783,18 @@ _public_ const char *udev_device_get_action(struct udev_device *udev_device)
  **/
 _public_ unsigned long long int udev_device_get_usec_since_initialized(struct udev_device *udev_device)
 {
-        unsigned long long now;
-
-        if (udev_device == NULL)
-                return 0;
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        if (udev_device->usec_initialized == 0)
-                return 0;
-        now = now_usec();
-        if (now == 0)
-                return 0;
-        return now - udev_device->usec_initialized;
-}
+        usec_t ts;
+        int r;
 
-unsigned long long udev_device_get_usec_initialized(struct udev_device *udev_device)
-{
-        return udev_device->usec_initialized;
-}
+        assert_return(udev_device, -EINVAL);
 
-void udev_device_set_usec_initialized(struct udev_device *udev_device, unsigned long long usec_initialized)
-{
-        char num[32];
+        r = sd_device_get_usec_since_initialized(udev_device->device, &ts);
+        if (r < 0) {
+                errno = EINVAL;
+                return 0;
+        }
 
-        udev_device->usec_initialized = usec_initialized;
-        snprintf(num, sizeof(num), "%llu", usec_initialized);
-        udev_device_add_property(udev_device, "USEC_INITIALIZED", num);
+        return ts;
 }
 
 /**
@@ -1284,127 +809,41 @@ void udev_device_set_usec_initialized(struct udev_device *udev_device, unsigned
  **/
 _public_ const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
 {
-        struct udev_list_entry *list_entry;
-        char path[UTIL_PATH_SIZE];
-        char value[4096];
-        struct stat statbuf;
-        int fd;
-        ssize_t size;
-        const char *val = NULL;
-
-        if (udev_device == NULL)
-                return NULL;
-        if (sysattr == NULL)
-                return NULL;
+        const char *value;
+        int r;
 
-        /* look for possibly already cached result */
-        list_entry = udev_list_get_entry(&udev_device->sysattr_value_list);
-        list_entry = udev_list_entry_get_by_name(list_entry, sysattr);
-        if (list_entry != NULL)
-                return udev_list_entry_get_value(list_entry);
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-        util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
-        if (lstat(path, &statbuf) != 0) {
-                udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, NULL);
-                goto out;
-        }
-
-        if (S_ISLNK(statbuf.st_mode)) {
-                struct udev_device *dev;
-
-                /*
-                 * Some core links return only the last element of the target path,
-                 * these are just values, the paths should not be exposed.
-                 */
-                if (strcmp(sysattr, "driver") == 0 ||
-                    strcmp(sysattr, "subsystem") == 0 ||
-                    strcmp(sysattr, "module") == 0) {
-                        if (util_get_sys_core_link_value(udev_device->udev, sysattr,
-                                                         udev_device->syspath, value, sizeof(value)) < 0)
-                                return NULL;
-                        list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
-                        val = udev_list_entry_get_value(list_entry);
-                        goto out;
-                }
-
-                /* resolve link to a device and return its syspath */
-                util_strscpyl(path, sizeof(path), udev_device->syspath, "/", sysattr, NULL);
-                dev = udev_device_new_from_syspath(udev_device->udev, path);
-                if (dev != NULL) {
-                        list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr,
-                                                         udev_device_get_syspath(dev));
-                        val = udev_list_entry_get_value(list_entry);
-                        udev_device_unref(dev);
-                }
-
-                goto out;
+        r = sd_device_get_sysattr_value(udev_device->device, sysattr, &value);
+        if (r < 0) {
+                errno = -r;
+                return NULL;
         }
 
-        /* skip directories */
-        if (S_ISDIR(statbuf.st_mode))
-                goto out;
-
-        /* skip non-readable files */
-        if ((statbuf.st_mode & S_IRUSR) == 0)
-                goto out;
-
-        /* read attribute value */
-        fd = open(path, O_RDONLY|O_CLOEXEC);
-        if (fd < 0)
-                goto out;
-        size = read(fd, value, sizeof(value));
-        close(fd);
-        if (size < 0)
-                goto out;
-        if (size == sizeof(value))
-                goto out;
-
-        /* got a valid value, store it in cache and return it */
-        value[size] = '\0';
-        util_remove_trailing_chars(value, '\n');
-        list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
-        val = udev_list_entry_get_value(list_entry);
-out:
-        return val;
+        return value;
 }
 
-static int udev_device_sysattr_list_read(struct udev_device *udev_device)
+/**
+ * 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, char *value)
 {
-        struct dirent *dent;
-        DIR *dir;
-        int num = 0;
-
-        if (udev_device == NULL)
-                return -1;
-        if (udev_device->sysattr_list_read)
-                return 0;
-
-        dir = opendir(udev_device_get_syspath(udev_device));
-        if (!dir)
-                return -1;
-
-        for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
-                char path[UTIL_PATH_SIZE];
-                struct stat statbuf;
+        int r;
 
-                /* only handle symlinks and regular files */
-                if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
-                        continue;
+        assert_return(udev_device, -EINVAL);
 
-                util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", dent->d_name, NULL);
-                if (lstat(path, &statbuf) != 0)
-                        continue;
-                if ((statbuf.st_mode & S_IRUSR) == 0)
-                        continue;
+        r = sd_device_set_sysattr_value(udev_device->device, sysattr, value);
+        if (r < 0)
+                return r;
 
-                udev_list_entry_add(&udev_device->sysattr_list, dent->d_name, NULL);
-                num++;
-        }
-
-        closedir(dir);
-        udev_device->sysattr_list_read = true;
-
-        return num;
+        return 0;
 }
 
 /**
@@ -1419,114 +858,20 @@ static int udev_device_sysattr_list_read(struct udev_device *udev_device)
  **/
 _public_ struct udev_list_entry *udev_device_get_sysattr_list_entry(struct udev_device *udev_device)
 {
-        if (!udev_device->sysattr_list_read) {
-                int ret;
-                ret = udev_device_sysattr_list_read(udev_device);
-                if (0 > ret)
-                        return NULL;
-        }
-
-        return udev_list_get_entry(&udev_device->sysattr_list);
-}
-
-int udev_device_set_syspath(struct udev_device *udev_device, const char *syspath)
-{
-        const char *pos;
-        size_t len;
-
-        free(udev_device->syspath);
-        udev_device->syspath = strdup(syspath);
-        if (udev_device->syspath ==  NULL)
-                return -ENOMEM;
-        udev_device->devpath = &udev_device->syspath[strlen(udev_get_sys_path(udev_device->udev))];
-        udev_device_add_property(udev_device, "DEVPATH", udev_device->devpath);
-
-        pos = strrchr(udev_device->syspath, '/');
-        if (pos == NULL)
-                return -EINVAL;
-        udev_device->sysname = strdup(&pos[1]);
-        if (udev_device->sysname == NULL)
-                return -ENOMEM;
-
-        /* some devices have '!' in their name, change that to '/' */
-        len = 0;
-        while (udev_device->sysname[len] != '\0') {
-                if (udev_device->sysname[len] == '!')
-                        udev_device->sysname[len] = '/';
-                len++;
-        }
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-        /* trailing number */
-        while (len > 0 && isdigit(udev_device->sysname[--len]))
-                udev_device->sysnum = &udev_device->sysname[len];
+        if (!udev_device->sysattrs_read) {
+                const char *sysattr;
 
-        /* sysname is completely numeric */
-        if (len == 0)
-                udev_device->sysnum = NULL;
+                udev_list_cleanup(&udev_device->sysattrs);
 
-        return 0;
-}
+                FOREACH_DEVICE_SYSATTR(udev_device->device, sysattr)
+                        udev_list_entry_add(&udev_device->properties, sysattr, NULL);
 
-int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode)
-{
-        free(udev_device->devnode);
-        if (devnode[0] != '/') {
-                if (asprintf(&udev_device->devnode, "%s/%s", udev_get_dev_path(udev_device->udev), devnode) < 0)
-                        udev_device->devnode = NULL;
-        } else {
-                udev_device->devnode = strdup(devnode);
+                udev_device->sysattrs_read = true;
         }
-        if (udev_device->devnode == NULL)
-                return -ENOMEM;
-        udev_device_add_property(udev_device, "DEVNAME", udev_device->devnode);
-        return 0;
-}
 
-int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink, int unique)
-{
-        struct udev_list_entry *list_entry;
-
-        udev_device->devlinks_uptodate = false;
-        list_entry = udev_list_entry_add(&udev_device->devlinks_list, devlink, NULL);
-        if (list_entry == NULL)
-                return -ENOMEM;
-        if (unique)
-                udev_list_entry_set_num(list_entry, true);
-        return 0;
-}
-
-const char *udev_device_get_id_filename(struct udev_device *udev_device)
-{
-        if (udev_device->id_filename == NULL) {
-                if (udev_device_get_subsystem(udev_device) == NULL)
-                        return NULL;
-
-                if (major(udev_device_get_devnum(udev_device)) > 0) {
-                        /* use dev_t -- b259:131072, c254:0 */
-                        if (asprintf(&udev_device->id_filename, "%c%u:%u",
-                                     strcmp(udev_device_get_subsystem(udev_device), "block") == 0 ? 'b' : 'c',
-                                     major(udev_device_get_devnum(udev_device)),
-                                     minor(udev_device_get_devnum(udev_device))) < 0)
-                                udev_device->id_filename = NULL;
-                } else if (udev_device_get_ifindex(udev_device) > 0) {
-                        /* use netdev ifindex -- n3 */
-                        if (asprintf(&udev_device->id_filename, "n%u", udev_device_get_ifindex(udev_device)) < 0)
-                                udev_device->id_filename = NULL;
-                } else {
-                        /*
-                         * use $subsys:$syname -- pci:0000:00:1f.2
-                         * sysname() has '!' translated, get it from devpath
-                         */
-                        const char *sysname;
-                        sysname = strrchr(udev_device->devpath, '/');
-                        if (sysname == NULL)
-                                return NULL;
-                        sysname = &sysname[1];
-                        if (asprintf(&udev_device->id_filename, "+%s:%s", udev_device_get_subsystem(udev_device), sysname) < 0)
-                                udev_device->id_filename = NULL;
-                }
-        }
-        return udev_device->id_filename;
+        return udev_list_get_entry(&udev_device->sysattrs);
 }
 
 /**
@@ -1544,30 +889,18 @@ const char *udev_device_get_id_filename(struct udev_device *udev_device)
  **/
 _public_ int udev_device_get_is_initialized(struct udev_device *udev_device)
 {
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        return udev_device->is_initialized;
-}
+        int r, initialized;
 
-void udev_device_set_is_initialized(struct udev_device *udev_device)
-{
-        udev_device->is_initialized = true;
-}
+        assert_return(udev_device, -EINVAL);
+
+        r = sd_device_get_is_initialized(udev_device->device, &initialized);
+        if (r < 0) {
+                errno = -r;
 
-int udev_device_add_tag(struct udev_device *udev_device, const char *tag)
-{
-        if (strchr(tag, ':') != NULL || strchr(tag, ' ') != NULL)
-                return -EINVAL;
-        udev_device->tags_uptodate = false;
-        if (udev_list_entry_add(&udev_device->tags_list, tag, NULL) != NULL)
                 return 0;
-        return -ENOMEM;
-}
+        }
 
-void udev_device_cleanup_tags_list(struct udev_device *udev_device)
-{
-        udev_device->tags_uptodate = false;
-        udev_list_cleanup(&udev_device->tags_list);
+        return initialized;
 }
 
 /**
@@ -1583,138 +916,34 @@ void udev_device_cleanup_tags_list(struct udev_device *udev_device)
  **/
 _public_ struct udev_list_entry *udev_device_get_tags_list_entry(struct udev_device *udev_device)
 {
-        if (udev_device == NULL)
-                return NULL;
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        return udev_list_get_entry(&udev_device->tags_list);
-}
+        assert_return_errno(udev_device, NULL, EINVAL);
 
-_public_ int udev_device_has_tag(struct udev_device *udev_device, const char *tag)
-{
-        struct udev_list_entry *list_entry;
-
-        if (udev_device == NULL)
-                return false;
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        list_entry = udev_device_get_tags_list_entry(udev_device);
-        if (udev_list_entry_get_by_name(list_entry, tag) != NULL)
-                return true;
-        return false;
-}
+        if (device_get_tags_generation(udev_device->device) != udev_device->tags_generation) {
+                const char *tag;
 
-#define ENVP_SIZE                        128
-#define MONITOR_BUF_SIZE                4096
-static int update_envp_monitor_buf(struct udev_device *udev_device)
-{
-        struct udev_list_entry *list_entry;
-        char *s;
-        size_t l;
-        unsigned int i;
-
-        /* monitor buffer of property strings */
-        free(udev_device->monitor_buf);
-        udev_device->monitor_buf_len = 0;
-        udev_device->monitor_buf = malloc(MONITOR_BUF_SIZE);
-        if (udev_device->monitor_buf == NULL)
-                return -ENOMEM;
-
-        /* envp array, strings will point into monitor buffer */
-        if (udev_device->envp == NULL)
-                udev_device->envp = malloc(sizeof(char *) * ENVP_SIZE);
-        if (udev_device->envp == NULL)
-                return -ENOMEM;
-
-        i = 0;
-        s = udev_device->monitor_buf;
-        l = MONITOR_BUF_SIZE;
-        udev_list_entry_foreach(list_entry, udev_device_get_properties_list_entry(udev_device)) {
-                const char *key;
-
-                key = udev_list_entry_get_name(list_entry);
-                /* skip private variables */
-                if (key[0] == '.')
-                        continue;
-
-                /* add string to envp array */
-                udev_device->envp[i++] = s;
-                if (i+1 >= ENVP_SIZE)
-                        return -EINVAL;
-
-                /* add property string to monitor buffer */
-                l = util_strpcpyl(&s, l, key, "=", udev_list_entry_get_value(list_entry), NULL);
-                if (l == 0)
-                        return -EINVAL;
-                /* advance past the trailing '\0' that util_strpcpyl() guarantees */
-                s++;
-                l--;
-        }
-        udev_device->envp[i] = NULL;
-        udev_device->monitor_buf_len = s - udev_device->monitor_buf;
-        udev_device->envp_uptodate = true;
-        return 0;
-}
-
-char **udev_device_get_properties_envp(struct udev_device *udev_device)
-{
-        if (!udev_device->envp_uptodate)
-                if (update_envp_monitor_buf(udev_device) != 0)
-                        return NULL;
-        return udev_device->envp;
-}
-
-ssize_t udev_device_get_properties_monitor_buf(struct udev_device *udev_device, const char **buf)
-{
-        if (!udev_device->envp_uptodate)
-                if (update_envp_monitor_buf(udev_device) != 0)
-                        return -EINVAL;
-        *buf = udev_device->monitor_buf;
-        return udev_device->monitor_buf_len;
-}
+                udev_list_cleanup(&udev_device->tags);
 
-int udev_device_set_action(struct udev_device *udev_device, const char *action)
-{
-        free(udev_device->action);
-        udev_device->action = strdup(action);
-        if (udev_device->action == NULL)
-                return -ENOMEM;
-        udev_device_add_property(udev_device, "ACTION", udev_device->action);
-        return 0;
-}
+                FOREACH_DEVICE_TAG(udev_device->device, tag)
+                        udev_list_entry_add(&udev_device->tags, tag, NULL);
 
-int udev_device_get_devlink_priority(struct udev_device *udev_device)
-{
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        return udev_device->devlink_priority;
-}
-
-int udev_device_set_devlink_priority(struct udev_device *udev_device, int prio)
-{
-         udev_device->devlink_priority = prio;
-        return 0;
-}
-
-int udev_device_get_watch_handle(struct udev_device *udev_device)
-{
-        if (!udev_device->info_loaded)
-                udev_device_read_db(udev_device, NULL);
-        return udev_device->watch_handle;
-}
+                udev_device->tags_generation = device_get_tags_generation(udev_device->device);
+        }
 
-int udev_device_set_watch_handle(struct udev_device *udev_device, int handle)
-{
-        udev_device->watch_handle = handle;
-        return 0;
+        return udev_list_get_entry(&udev_device->tags);
 }
 
-bool udev_device_get_db_persist(struct udev_device *udev_device)
+/**
+ * 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)
 {
-        return udev_device->db_persist;
-}
+        assert_return(udev_device, 0);
 
-void udev_device_set_db_persist(struct udev_device *udev_device)
-{
-        udev_device->db_persist = true;
+        return sd_device_has_tag(udev_device->device, tag);
 }