move imported udev into place

1 files changed, 1744 insertions, 0 deletions

diff --git a/src/udev/libudev-device.c b/src/udev/libudev-device.c
new file mode 100644
index 0000000000..10f28b8cd5
--- /dev/null
+++ b/src/udev/libudev-device.c
@@ -0,0 +1,1744 @@
+/*
+ * 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]);
+                        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);
+        }
+
+        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;
+}