merge udev/, libudev/, systemd/ files in src/; move extras/ to src/

1 files changed, 1737 insertions, 0 deletions

diff --git a/src/libudev-device.c b/src/libudev-device.c
new file mode 100644
index 0000000000..e5950bb4b1
--- /dev/null
+++ b/src/libudev-device.c
@@ -0,0 +1,1737 @@
+/*
+ * libudev - interface to udev device information
+ *
+ * Copyright (C) 2008-2010 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stddef.h>
+#include <unistd.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <string.h>
+#include <dirent.h>
+#include <fcntl.h>
+#include <ctype.h>
+#include <net/if.h>
+#include <sys/stat.h>
+#include <sys/ioctl.h>
+#include <sys/socket.h>
+#include <linux/sockios.h>
+
+#include "libudev.h"
+#include "libudev-private.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 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
+ *
+ * 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.
+ **/
+UDEV_EXPORT 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];
+
+	udev_device->seqnum = seqnum;
+	snprintf(num, sizeof(num), "%llu", seqnum);
+	udev_device_add_property(udev_device, "SEQNUM", num);
+	return 0;
+}
+
+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;
+}
+
+static int udev_device_set_ifindex(struct udev_device *udev_device, int ifindex)
+{
+	char num[32];
+
+	udev_device->ifindex = ifindex;
+	snprintf(num, sizeof(num), "%u", ifindex);
+	udev_device_add_property(udev_device, "IFINDEX", num);
+	return 0;
+}
+
+/**
+ * udev_device_get_devnum:
+ * @udev_device: udev device
+ *
+ * Returns: the device major/minor number.
+ **/
+UDEV_EXPORT 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;
+}
+
+static int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
+{
+	const char *pos;
+
+	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);
+
+	pos = strrchr(udev_device->devpath_old, '/');
+	if (pos == NULL)
+		return -EINVAL;
+	return 0;
+}
+
+/**
+ * udev_device_get_driver:
+ * @udev_device: udev device
+ *
+ * Returns: the driver string, or #NULL if there is no driver attached.
+ **/
+UDEV_EXPORT const char *udev_device_get_driver(struct udev_device *udev_device)
+{
+	char driver[UTIL_NAME_SIZE];
+
+	if (udev_device == NULL)
+		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;
+}
+
+/**
+ * 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 can not be determined
+ **/
+UDEV_EXPORT const char *udev_device_get_devtype(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		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;
+}
+
+/**
+ * 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 can not be determined
+ **/
+UDEV_EXPORT 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;
+}
+
+static int udev_device_set_devnode_mode(struct udev_device *udev_device, mode_t mode)
+{
+	char num[32];
+
+	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);
+		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;
+}
+
+/**
+ * udev_device_get_property_value:
+ * @udev_device: udev device
+ * @key: property name
+ *
+ * Returns: the value of a device property, or #NULL if there is no such property.
+ **/
+UDEV_EXPORT 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) {
+		info(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);
+
+	info(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;
+
+	if (udev_device->uevent_loaded)
+		return 0;
+
+	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]);
+		else 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, "IFINDEX=", 8) == 0)
+			udev_device_set_ifindex(udev_device, strtoull(&line[8], NULL, 10));
+		else if (strncmp(line, "DEVNAME=", 8) == 0)
+			udev_device_set_devnode(udev_device, &line[8]);
+		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);
+	}
+
+	udev_device->devnum = makedev(maj, min);
+	fclose(f);
+	return 0;
+}
+
+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;
+	struct udev_list_entry *list_entry;
+
+	if (udev == NULL)
+		return NULL;
+
+	udev_device = calloc(1, sizeof(struct udev_device));
+	if (udev_device == NULL)
+		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));
+	dbg(udev_device->udev, "udev_device: %p created\n", udev_device);
+	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
+ **/
+UDEV_EXPORT 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;
+	struct udev_device *udev_device;
+
+	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) {
+		info(udev, "not in sys :%s\n", syspath);
+		return NULL;
+	}
+
+	/* path is not a root directory */
+	subdir = &syspath[len+1];
+	pos = strrchr(subdir, '/');
+	if (pos == NULL || pos[1] == '\0' || pos < &subdir[2]) {
+		dbg(udev, "not a subdir :%s\n", syspath);
+		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) {
+			dbg(udev, "not a device: %s\n", syspath);
+			return NULL;
+		}
+	} else {
+		/* everything else just needs to be a directory */
+		if (stat(path, &statbuf) != 0 || !S_ISDIR(statbuf.st_mode)) {
+			dbg(udev, "directory not found: %s\n", syspath);
+			return NULL;
+		}
+	}
+
+	udev_device = udev_device_new(udev);
+	if (udev_device == NULL)
+		return NULL;
+
+	udev_device_set_syspath(udev_device, path);
+	info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
+
+	return 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
+ **/
+UDEV_EXPORT 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
+		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);
+}
+
+struct udev_device *udev_device_new_from_id_filename(struct udev *udev, 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);
+		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:
+		return NULL;
+	}
+}
+
+/**
+ * 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
+ **/
+UDEV_EXPORT 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;
+	}
+
+	if (strcmp(subsystem, "module") == 0) {
+		util_strscpyl(path, l, "/module/", sysname, NULL);
+		if (stat(path_full, &statbuf) == 0)
+			goto found;
+		goto out;
+	}
+
+	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;
+	}
+
+	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);
+}
+
+/**
+ * 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
+ **/
+UDEV_EXPORT struct udev_device *udev_device_new_from_environment(struct udev *udev)
+{
+	int i;
+	struct udev_device *udev_device;
+
+	udev_device = udev_device_new(udev);
+	if (udev_device == NULL)
+		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) {
+		info(udev, "missing values, invalid device\n");
+		udev_device_unref(udev_device);
+		udev_device = NULL;
+	}
+
+	return udev_device;
+}
+
+static struct udev_device *device_new_from_parent(struct udev_device *udev_device)
+{
+	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;
+	}
+	return NULL;
+}
+
+/**
+ * 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.
+ *
+ * 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.
+ *
+ * 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.
+ **/
+UDEV_EXPORT struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	if (!udev_device->parent_set) {
+		udev_device->parent_set = true;
+		udev_device->parent_device = device_new_from_parent(udev_device);
+	}
+	if (udev_device->parent_device != NULL)
+		dbg(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
+	return udev_device->parent_device;
+}
+
+/**
+ * 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.
+ *
+ * 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.
+ *
+ * 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.
+ **/
+UDEV_EXPORT 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;
+
+	if (subsystem == NULL)
+		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);
+	}
+	return parent;
+}
+
+/**
+ * udev_device_get_udev:
+ * @udev_device: udev device
+ *
+ * Retrieve the udev library context the device was created with.
+ *
+ * Returns: the udev library context
+ **/
+UDEV_EXPORT struct udev *udev_device_get_udev(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->udev;
+}
+
+/**
+ * udev_device_ref:
+ * @udev_device: udev device
+ *
+ * Take a reference of a udev device.
+ *
+ * Returns: the passed udev device
+ **/
+UDEV_EXPORT struct udev_device *udev_device_ref(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	udev_device->refcount++;
+	return 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.
+ *
+ **/
+UDEV_EXPORT void 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);
+	dbg(udev_device->udev, "udev_device: %p released\n", udev_device);
+	free(udev_device);
+}
+
+/**
+ * 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
+ **/
+UDEV_EXPORT const char *udev_device_get_devpath(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->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
+ **/
+UDEV_EXPORT const char *udev_device_get_syspath(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->syspath;
+}
+
+/**
+ * udev_device_get_sysname:
+ * @udev_device: udev device
+ *
+ * Returns: the sys name of the device device
+ **/
+UDEV_EXPORT const char *udev_device_get_sysname(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->sysname;
+}
+
+/**
+ * udev_device_get_sysnum:
+ * @udev_device: udev device
+ *
+ * Returns: the trailing number of of the device name
+ **/
+UDEV_EXPORT const char *udev_device_get_sysnum(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->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
+ **/
+UDEV_EXPORT const char *udev_device_get_devnode(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		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;
+}
+
+/**
+ * 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_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
+ **/
+UDEV_EXPORT 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);
+}
+
+void udev_device_cleanup_devlinks_list(struct udev_device *udev_device)
+{
+	udev_device->devlinks_uptodate = false;
+	udev_list_cleanup(&udev_device->devlinks_list);
+}
+
+/**
+ * udev_device_get_properties_list_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_next(),
+ * which returns #NULL if no more entries exist. The property name
+ * can be retrieved from the list entry by udev_list_get_name(),
+ * the property value by udev_list_get_value().
+ *
+ * Returns: the first entry of the property list
+ **/
+UDEV_EXPORT 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);
+		}
+	}
+	return udev_list_get_entry(&udev_device->properties_list);
+}
+
+/**
+ * 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.
+ **/
+UDEV_EXPORT const char *udev_device_get_action(struct udev_device *udev_device)
+{
+	if (udev_device == NULL)
+		return NULL;
+	return udev_device->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.
+ **/
+UDEV_EXPORT 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;
+}
+
+unsigned long long udev_device_get_usec_initialized(struct udev_device *udev_device)
+{
+	return udev_device->usec_initialized;
+}
+
+void udev_device_set_usec_initialized(struct udev_device *udev_device, unsigned long long usec_initialized)
+{
+	char num[32];
+
+	udev_device->usec_initialized = usec_initialized;
+	snprintf(num, sizeof(num), "%llu", usec_initialized);
+	udev_device_add_property(udev_device, "USEC_INITIALIZED", num);
+}
+
+/**
+ * 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.
+ **/
+UDEV_EXPORT 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;
+
+	/* 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) {
+		dbg(udev_device->udev, "got '%s' (%s) from cache\n",
+		    sysattr, udev_list_entry_get_value(list_entry));
+		return udev_list_entry_get_value(list_entry);
+	}
+
+	util_strscpyl(path, sizeof(path), udev_device_get_syspath(udev_device), "/", sysattr, NULL);
+	if (lstat(path, &statbuf) != 0) {
+		dbg(udev_device->udev, "no attribute '%s', keep negative entry\n", path);
+		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;
+			dbg(udev_device->udev, "cache '%s' with link value '%s'\n", sysattr, value);
+			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;
+	}
+
+	/* 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) {
+		dbg(udev_device->udev, "attribute '%s' can not be opened\n", path);
+		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');
+	dbg(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
+	list_entry = udev_list_entry_add(&udev_device->sysattr_value_list, sysattr, value);
+	val = udev_list_entry_get_value(list_entry);
+out:
+	return val;
+}
+
+static int udev_device_sysattr_list_read(struct udev_device *udev_device)
+{
+	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) {
+		dbg(udev_device->udev, "sysfs dir '%s' can not be opened\n",
+				udev_device_get_syspath(udev_device));
+		return -1;
+	}
+
+	for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
+		char path[UTIL_PATH_SIZE];
+		struct stat statbuf;
+
+		/* only handle symlinks and regular files */
+		if (dent->d_type != DT_LNK && dent->d_type != DT_REG)
+			continue;
+
+		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;
+
+		udev_list_entry_add(&udev_device->sysattr_list, dent->d_name, NULL);
+		num++;
+	}
+
+	closedir(dir);
+	dbg(udev_device->udev, "found %d sysattrs for '%s'\n", num, udev_device_get_syspath(udev_device));
+	udev_device->sysattr_list_read = true;
+
+	return num;
+}
+
+/**
+ * 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
+ **/
+UDEV_EXPORT 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++;
+	}
+
+	/* trailing number */
+	while (len > 0 && isdigit(udev_device->sysname[--len]))
+		udev_device->sysnum = &udev_device->sysname[len];
+
+	/* sysname is completely numeric */
+	if (len == 0)
+		udev_device->sysnum = NULL;
+
+	return 0;
+}
+
+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);
+	}
+	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;
+}
+
+/**
+ * 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.
+ **/
+UDEV_EXPORT 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;
+}
+
+void udev_device_set_is_initialized(struct udev_device *udev_device)
+{
+	udev_device->is_initialized = true;
+}
+
+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);
+}
+
+/**
+ * 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_next(),
+ * which returns #NULL if no more entries exist. The tag string
+ * can be retrieved from the list entry by udev_list_get_name().
+ *
+ * Returns: the first entry of the tag list
+ **/
+UDEV_EXPORT 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);
+}
+
+UDEV_EXPORT 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;
+}
+
+#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;
+	dbg(udev_device->udev, "filled envp/monitor buffer, %u properties, %zu bytes\n",
+	    i, udev_device->monitor_buf_len);
+	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;
+}
+
+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;
+}
+
+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;
+}
+
+int udev_device_set_watch_handle(struct udev_device *udev_device, int handle)
+{
+	udev_device->watch_handle = handle;
+	return 0;
+}
+
+bool udev_device_get_db_persist(struct udev_device *udev_device)
+{
+	return udev_device->db_persist;
+}
+
+void udev_device_set_db_persist(struct udev_device *udev_device)
+{
+	udev_device->db_persist = true;
+}