chiark / gitweb /
libudev: update documentation
[elogind.git] / libudev / libudev-device.c
index 96cc2dba1c653808dd706055bf8576bfc3ff0031..410f75b3008d7054bc7d053403902ffb548526e2 100644 (file)
@@ -1,7 +1,7 @@
 /*
  * libudev - interface to udev device information
  *
- * Copyright (C) 2008-2009 Kay Sievers <kay.sievers@vrfy.org>
+ * 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
@@ -13,6 +13,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <unistd.h>
+#include <stdbool.h>
 #include <errno.h>
 #include <string.h>
 #include <dirent.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;
@@ -36,6 +52,7 @@ struct udev_device {
        char *driver;
        char *action;
        char *devpath_old;
+       char *sysname_old;
        char *knodename;
        char **envp;
        char *monitor_buf;
@@ -51,6 +68,7 @@ struct udev_device {
        int refcount;
        dev_t devnum;
        int watch_handle;
+       int maj, min;
        unsigned int parent_set:1;
        unsigned int subsystem_set:1;
        unsigned int devtype_set:1;
@@ -61,14 +79,128 @@ struct udev_device {
        unsigned int ignore_remove:1;
 };
 
-static size_t devpath_to_db_path(struct udev *udev, const char *devpath, char *filename, size_t len)
+struct udev_list_entry *udev_device_add_property(struct udev_device *udev_device, const char *key, const char *value)
 {
-       char *s;
-       size_t l;
+       udev_device->envp_uptodate = 0;
+       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->udev, &udev_device->properties_list, key, value, 1, 0);
+}
+
+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) {
+               if (property[8] == '/')
+                       udev_device_set_devnode(udev_device, &property[8]);
+               else
+                       udev_device_set_knodename(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, "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, "TIMEOUT=", 8) == 0) {
+               udev_device_set_timeout(udev_device, strtoull(&property[8], NULL, 10));
+       } 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.
+ **/
+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;
 
-       s = filename;
-       l = util_strpcpyl(&s, len, udev_get_dev_path(udev), "/.udev/db/", NULL);
-       return util_path_encode(devpath, s, l);
+       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)
@@ -78,7 +210,8 @@ int udev_device_read_db(struct udev_device *udev_device)
        char line[UTIL_LINE_SIZE];
        FILE *f;
 
-       devpath_to_db_path(udev_device->udev, udev_device->devpath, filename, sizeof(filename));
+       util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/.udev/db/",
+                     udev_device_get_subsystem(udev_device), ":", udev_device_get_sysname(udev_device), NULL);
 
        if (lstat(filename, &stats) != 0) {
                dbg(udev_device->udev, "no db file to read %s: %m\n", filename);
@@ -116,7 +249,7 @@ int udev_device_read_db(struct udev_device *udev_device)
                                next = &next[1];
                        }
                        util_strscpyl(devlink, sizeof(devlink), udev_get_dev_path(udev_device->udev), "/", lnk, NULL);
-                       udev_device_add_devlink(udev_device, devlink);
+                       udev_device_add_devlink(udev_device, devlink, 0);
                }
                info(udev_device->udev, "device %p filled with db symlink data '%s'\n", udev_device, udev_device->devnode);
                return 0;
@@ -143,7 +276,7 @@ int udev_device_read_db(struct udev_device *udev_device)
                        break;
                case 'S':
                        util_strscpyl(filename, sizeof(filename), udev_get_dev_path(udev_device->udev), "/", val, NULL);
-                       udev_device_add_devlink(udev_device, filename);
+                       udev_device_add_devlink(udev_device, filename, 0);
                        break;
                case 'L':
                        udev_device_set_devlink_priority(udev_device, atoi(val));
@@ -255,7 +388,7 @@ struct udev_device *udev_device_new(struct udev *udev)
  * @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 sypath is the absolute
+ * 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
@@ -296,25 +429,7 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
        util_strscpy(path, sizeof(path), syspath);
        util_resolve_sys_link(udev, path, sizeof(path));
 
-       /* try to resolve the silly block layout if needed */
-       if (strncmp(&path[len], "/block/", 7) == 0) {
-               char block[UTIL_PATH_SIZE];
-               char part[UTIL_PATH_SIZE];
-
-               util_strscpy(block, sizeof(block), path);
-               pos = strrchr(block, '/');
-               if (pos == NULL)
-                       return NULL;
-               util_strscpy(part, sizeof(part), pos);
-               pos[0] = '\0';
-               if (util_resolve_sys_link(udev, block, sizeof(block)) == 0)
-                       util_strscpyl(path, sizeof(path), block, part, NULL);
-       }
-
-       /* path exists in sys */
-       if (strncmp(&syspath[len], "/devices/", 9) == 0 ||
-           strncmp(&syspath[len], "/class/", 7) == 0 ||
-           strncmp(&syspath[len], "/block/", 7) == 0) {
+       if (strncmp(&syspath[len], "/devices/", 9) == 0) {
                char file[UTIL_PATH_SIZE];
 
                /* all "devices" require a "uevent" file */
@@ -341,13 +456,26 @@ struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *
        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
+ **/
 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;
-       struct udev_enumerate *udev_enumerate;
-       struct udev_list_entry *list_entry;
-       struct udev_device *device = NULL;
 
        if (type == 'b')
                type_str = "block";
@@ -356,42 +484,27 @@ struct udev_device *udev_device_new_from_devnum(struct udev *udev, char type, de
        else
                return NULL;
 
-       /* /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));
-       if (util_resolve_sys_link(udev, path, sizeof(path)) == 0)
-               return udev_device_new_from_syspath(udev, path);
-
-       udev_enumerate = udev_enumerate_new(udev);
-       if (udev_enumerate == NULL)
-               return NULL;
-
-       /* fallback to search sys devices for the major/minor */
-       if (type == 'b')
-               udev_enumerate_add_match_subsystem(udev_enumerate, "block");
-       else if (type == 'c')
-               udev_enumerate_add_nomatch_subsystem(udev_enumerate, "block");
-       udev_enumerate_scan_devices(udev_enumerate);
-       udev_list_entry_foreach(list_entry, udev_enumerate_get_list_entry(udev_enumerate)) {
-               struct udev_device *device_loop;
-
-               device_loop = udev_device_new_from_syspath(udev, udev_list_entry_get_name(list_entry));
-               if (device_loop != NULL) {
-                       if (udev_device_get_devnum(device_loop) == devnum) {
-                               if (type == 'b' && strcmp(udev_device_get_subsystem(device_loop), "block") != 0)
-                                       continue;
-                               if (type == 'c' && strcmp(udev_device_get_subsystem(device_loop), "block") == 0)
-                                       continue;
-                               device = device_loop;
-                               break;
-                       }
-                       udev_device_unref(device_loop);
-               }
-       }
-       udev_enumerate_unref(udev_enumerate);
-       return device;
+       /* 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);
 }
 
+/**
+ * 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
+ **/
 struct udev_device *udev_device_new_from_subsystem_sysname(struct udev *udev, const char *subsystem, const char *sysname)
 {
        char path_full[UTIL_PATH_SIZE];
@@ -462,26 +575,51 @@ 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
+ **/
+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;
 
-       /* follow "device" link in deprecated sys layout */
-       if (strncmp(udev_device->devpath, "/class/", 7) == 0 ||
-           strncmp(udev_device->devpath, "/block/", 7) == 0) {
-               util_strscpyl(path, sizeof(path), udev_device->syspath, "/device", NULL);
-               if (util_resolve_sys_link(udev_device->udev, path, sizeof(path)) == 0) {
-                       udev_device_parent = udev_device_new_from_syspath(udev_device->udev, path);
-                       if (udev_device_parent != NULL)
-                               return udev_device_parent;
-               }
-       }
-
        util_strscpy(path, sizeof(path), udev_device->syspath);
        subdir = &path[strlen(udev_get_sys_path(udev_device->udev))+1];
-       while (1) {
+       for (;;) {
                char *pos;
 
                pos = strrchr(subdir, '/');
@@ -495,6 +633,25 @@ static struct udev_device *device_new_from_parent(struct udev_device *udev_devic
        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.
+ **/
 struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -508,6 +665,28 @@ struct udev_device *udev_device_get_parent(struct udev_device *udev_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.
+ **/
 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;
@@ -591,6 +770,7 @@ void udev_device_unref(struct udev_device *udev_device)
        free(udev_device->action);
        free(udev_device->driver);
        free(udev_device->devpath_old);
+       free(udev_device->sysname_old);
        free(udev_device->knodename);
        udev_list_cleanup_entries(udev_device->udev, &udev_device->sysattr_list);
        free(udev_device->envp);
@@ -631,6 +811,12 @@ const char *udev_device_get_syspath(struct udev_device *udev_device)
        return udev_device->syspath;
 }
 
+/**
+ * udev_device_get_sysname:
+ * @udev_device: udev device
+ *
+ * Returns: the sys name of the device device
+ **/
 const char *udev_device_get_sysname(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -638,6 +824,12 @@ const char *udev_device_get_sysname(struct udev_device *udev_device)
        return udev_device->sysname;
 }
 
+/**
+ * udev_device_get_sysnum:
+ * @udev_device: udev device
+ *
+ * Returns: the trailing number of of the device name
+ **/
 const char *udev_device_get_sysnum(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -680,7 +872,7 @@ const char *udev_device_get_subsystem(struct udev_device *udev_device)
                return NULL;
        if (!udev_device->subsystem_set) {
                udev_device->subsystem_set = 1;
-               /* read "subsytem" link */
+               /* read "subsystem" link */
                if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) > 0) {
                        udev_device_set_subsystem(udev_device, subsystem);
                        return udev_device->subsystem;
@@ -790,6 +982,12 @@ struct udev_list_entry *udev_device_get_properties_list_entry(struct udev_device
        return udev_list_get_entry(&udev_device->properties_list);
 }
 
+/**
+ * udev_device_get_driver:
+ * @udev_device: udev device
+ *
+ * Returns: the driver string, or #NULL if there is no driver attached.
+ **/
 const char *udev_device_get_driver(struct udev_device *udev_device)
 {
        char driver[UTIL_NAME_SIZE];
@@ -804,6 +1002,12 @@ const char *udev_device_get_driver(struct udev_device *udev_device)
        return udev_device->driver;
 }
 
+/**
+ * udev_device_get_devnum:
+ * @udev_device: udev device
+ *
+ * Returns: the device major/minor number.
+ **/
 dev_t udev_device_get_devnum(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -813,6 +1017,16 @@ dev_t udev_device_get_devnum(struct udev_device *udev_device)
        return udev_device->devnum;
 }
 
+/**
+ * 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.
+ **/
 const char *udev_device_get_action(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -820,6 +1034,15 @@ const char *udev_device_get_action(struct udev_device *udev_device)
        return udev_device->action;
 }
 
+/**
+ * udev_device_get_devnum:
+ * @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.
+ **/
 unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
 {
        if (udev_device == NULL)
@@ -827,6 +1050,16 @@ unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
        return udev_device->seqnum;
 }
 
+/**
+ * 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.
+ **/
 const char *udev_device_get_sysattr_value(struct udev_device *udev_device, const char *sysattr)
 {
        struct udev_list_entry *list_entry;
@@ -986,59 +1219,19 @@ int udev_device_set_devnode(struct udev_device *udev_device, const char *devnode
        return 0;
 }
 
-int udev_device_add_devlink(struct udev_device *udev_device, const char *devlink)
+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 = 0;
-       if (udev_list_entry_add(udev_device->udev, &udev_device->devlinks_list, devlink, NULL, 1, 0) == NULL)
+       list_entry = udev_list_entry_add(udev_device->udev, &udev_device->devlinks_list, devlink, NULL, 1, 0);
+       if (list_entry == NULL)
                return -ENOMEM;
+       if (unique)
+               udev_list_entry_set_flags(list_entry, 1);
        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 = 0;
-       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->udev, &udev_device->properties_list, key, value, 1, 0);
-}
-
-struct udev_list_entry *udev_device_add_property_from_string(struct udev_device *udev_device, const char *property)
-{
-       char name[UTIL_PATH_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);
-}
-
-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);
-}
-
 #define ENVP_SIZE                      128
 #define MONITOR_BUF_SIZE               4096
 static int update_envp_monitor_buf(struct udev_device *udev_device)
@@ -1065,17 +1258,25 @@ static int update_envp_monitor_buf(struct udev_device *udev_device)
        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, udev_list_entry_get_name(list_entry), "=",
-                                 udev_list_entry_get_value(list_entry), NULL);
+               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;
@@ -1130,13 +1331,39 @@ const char *udev_device_get_devpath_old(struct udev_device *udev_device)
 
 int udev_device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
 {
+       const char *pos;
+       size_t len;
+
+       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;
+       udev_device->sysname_old = strdup(&pos[1]);
+       if (udev_device->sysname_old == NULL)
+               return -ENOMEM;
+
+       /* some devices have '!' in their name, change that to '/' */
+       len = 0;
+       while (udev_device->sysname_old[len] != '\0') {
+               if (udev_device->sysname_old[len] == '!')
+                       udev_device->sysname_old[len] = '/';
+               len++;
+       }
        return 0;
 }
 
+const char *udev_device_get_sysname_old(struct udev_device *udev_device)
+{
+       if (udev_device == NULL)
+               return NULL;
+       return udev_device->sysname_old;
+}
+
 const char *udev_device_get_knodename(struct udev_device *udev_device)
 {
        return udev_device->knodename;
@@ -1144,9 +1371,11 @@ const char *udev_device_get_knodename(struct udev_device *udev_device)
 
 int udev_device_set_knodename(struct udev_device *udev_device, const char *knodename)
 {
+       free(udev_device->knodename);
        udev_device->knodename = strdup(knodename);
        if (udev_device->knodename == NULL)
                return -ENOMEM;
+       udev_device_add_property(udev_device, "DEVNAME", udev_device->knodename);
        return 0;
 }