libudev-device.c revision 8753fadf2a6ecead372e71b8bf9336cf29f9c958
/*
* libudev - interface to udev device information
*
* Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <dirent.h>
#include <fcntl.h>
#include <sys/stat.h>
#include "libudev.h"
#include "libudev-private.h"
struct udev_device {
int refcount;
struct udev *udev;
struct udev_device *parent_device;
char *syspath;
const char *devpath;
const char *sysname;
char *devname;
char *subsystem;
struct list_head link_list;
struct list_head env_list;
char *action;
char *driver;
char *devpath_old;
char *physdevpath;
int timeout;
dev_t devnum;
unsigned long long int seqnum;
int num_fake_partitions;
int devlink_priority;
int ignore_remove;
struct list_head attr_list;
};
static size_t syspath_to_db_path(struct udev_device *udev_device, char *filename, size_t len)
{
size_t start;
/* translate to location of db file */
util_strlcpy(filename, udev_get_dev_path(udev_device->udev), len);
start = util_strlcat(filename, "/.udev/db/", len);
util_strlcat(filename, udev_device->devpath, len);
return util_path_encode(&filename[start], len - start);
}
static int device_read_db(struct udev_device *udev_device)
{
struct stat stats;
char filename[UTIL_PATH_SIZE];
char line[UTIL_LINE_SIZE];
FILE *f;
int rc = 0;
syspath_to_db_path(udev_device, filename, sizeof(filename));
if (lstat(filename, &stats) != 0) {
info(udev_device->udev, "no db file to read %s: %s\n", filename, strerror(errno));
return -1;
}
if ((stats.st_mode & S_IFMT) == S_IFLNK) {
char target[UTIL_PATH_SIZE];
int target_len;
info(udev_device->udev, "found a symlink as db file\n");
target_len = readlink(filename, target, sizeof(target));
if (target_len > 0)
target[target_len] = '\0';
else {
info(udev_device->udev, "error reading db link %s: %s\n", filename, strerror(errno));
return -1;
}
dbg(udev_device->udev, "db link points to '%s'\n", target);
if (asprintf(&udev_device->devname, "%s/%s", udev_get_dev_path(udev_device->udev), target) < 0)
return -ENOMEM;
return 0;
}
f = fopen(filename, "r");
if (f == NULL) {
info(udev_device->udev, "error reading db file %s: %s\n", filename, strerror(errno));
return -1;
}
while (fgets(line, sizeof(line), f)) {
ssize_t len;
const char *val;
unsigned int maj, min;
len = strlen(line);
if (len < 4)
break;
line[len-1] = '\0';
val = &line[2];
switch(line[0]) {
case 'N':
asprintf(&udev_device->devname, "%s/%s", udev_get_dev_path(udev_device->udev), val);
break;
case 'M':
sscanf(val, "%u:%u", &maj, &min);
device_set_devnum(udev_device, makedev(maj, min));
break;
case 'S':
util_strlcpy(filename, udev_get_dev_path(udev_device->udev), sizeof(filename));
util_strlcat(filename, "/", sizeof(filename));
util_strlcat(filename, val, sizeof(filename));
device_add_devlink(udev_device, filename);
break;
case 'L':
device_set_devlink_priority(udev_device, atoi(val));
break;
case 'T':
device_set_timeout(udev_device, atoi(val));
break;
case 'A':
device_set_num_fake_partitions(udev_device, atoi(val));
break;
case 'R':
device_set_ignore_remove(udev_device, atoi(val));
break;
case 'E':
device_add_property_from_string(udev_device, val);
break;
}
}
fclose(f);
return rc;
}
struct udev_device *device_init(struct udev *udev)
{
struct udev_device *udev_device;
if (udev == NULL)
return NULL;
udev_device = malloc(sizeof(struct udev_device));
if (udev_device == NULL)
return NULL;
memset(udev_device, 0x00, sizeof(struct udev_device));
udev_device->refcount = 1;
udev_device->udev = udev;
INIT_LIST_HEAD(&udev_device->link_list);
INIT_LIST_HEAD(&udev_device->env_list);
INIT_LIST_HEAD(&udev_device->attr_list);
info(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 sypath 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 ressources of the udev device.
*
* Returns: a new udev device, or #NULL, if it does not exist
**/
struct udev_device *udev_device_new_from_syspath(struct udev *udev, const char *syspath)
{
char path[UTIL_PATH_SIZE];
struct stat statbuf;
struct udev_device *udev_device;
if (udev == NULL)
return NULL;
if (syspath == NULL)
return NULL;
util_strlcpy(path, syspath, sizeof(path));
util_strlcat(path, "/uevent", sizeof(path));
if (stat(path, &statbuf) != 0) {
info(udev, "not a device :%s\n", syspath);
return NULL;
}
udev_device = device_init(udev);
if (udev_device == NULL)
return NULL;
/* resolve possible symlink to real path */
util_strlcpy(path, syspath, sizeof(path));
util_resolve_sys_link(udev, path, sizeof(path));
device_set_syspath(udev_device, path);
info(udev, "device %p has devpath '%s'\n", udev_device, udev_device_get_devpath(udev_device));
if (device_read_db(udev_device) >= 0)
info(udev, "device %p filled with udev database data\n", udev_device);
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];
char *pos;
if (udev_device == NULL)
return NULL;
util_strlcpy(path, udev_device->syspath, sizeof(path));
while (1) {
pos = strrchr(path, '/');
if (pos == path || pos == NULL)
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;
}
/* follow "device" link in deprecated sys /sys/class/ layout */
if (strncmp(udev_device->devpath, "/class/", 7) == 0) {
util_strlcpy(path, udev_device->syspath, sizeof(path));
util_strlcat(path, "/device", sizeof(path));
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;
}
}
return NULL;
}
struct udev_device *udev_device_get_parent(struct udev_device *udev_device)
{
if (udev_device->parent_device != NULL) {
info(udev_device->udev, "returning existing parent %p\n", udev_device->parent_device);
return udev_device->parent_device;
}
udev_device->parent_device = device_new_from_parent(udev_device);
return udev_device->parent_device;
}
/**
* udev_device_get_udev:
* @udev_device: udev device
*
* Retrieve the udev library context the device was created with.
*
* Returns: the udev library context
**/
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
**/
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 ressources of the device will be released.
*
**/
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->devname);
free(udev_device->subsystem);
util_name_list_cleanup(udev_device->udev, &udev_device->link_list);
util_name_list_cleanup(udev_device->udev, &udev_device->env_list);
free(udev_device->action);
free(udev_device->driver);
free(udev_device->devpath_old);
free(udev_device->physdevpath);
util_name_list_cleanup(udev_device->udev, &udev_device->attr_list);
info(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
**/
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
**/
const char *udev_device_get_syspath(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->syspath;
}
const char *udev_device_get_sysname(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->sysname;
}
/**
* udev_device_get_devname:
* @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
**/
const char *udev_device_get_devname(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->devname;
}
/**
* 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
**/
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 != NULL)
return udev_device->subsystem;
/* read "subsytem" link */
if (util_get_sys_subsystem(udev_device->udev, udev_device->syspath, subsystem, sizeof(subsystem)) == 0) {
udev_device->subsystem = strdup(subsystem);
return udev_device->subsystem;
}
/* implicit names */
if (strncmp(udev_device->devpath, "/module/", 8) == 0) {
udev_device->subsystem = strdup("module");
return udev_device->subsystem;
}
if (strstr(udev_device->devpath, "/drivers/") != NULL) {
udev_device->subsystem = strdup("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->subsystem = strdup("subsystem");
return udev_device->subsystem;
}
return NULL;
}
/**
* udev_device_get_devlinks:
* @udev_device: udev device
* @cb: function to be called for every device link found
* @data: data to be passed to the function
*
* Retrieve the device links pointing to the device file of the
* udev device. For every device link, the passed function will be
* called with the device link string.
* The path is an absolute path, and starts with the device directory.
* If the function returns 1, remaning device links will be ignored.
*
* Returns: the number of device links passed to the caller, or a negative value on error
**/
int udev_device_get_devlinks(struct udev_device *udev_device,
int (*cb)(struct udev_device *udev_device, const char *value, void *data),
void *data)
{
struct util_name_entry *name_loop;
int count = 0;
if (udev_device == NULL)
return -1;
list_for_each_entry(name_loop, &udev_device->link_list, node) {
count++;
if (cb(udev_device, name_loop->name, data) != 0)
break;
}
return count;
}
/**
* udev_device_get_properties:
* @udev_device: udev device
* @cb: function to be called for every property found
* @data: data to be passed to the function
*
* Retrieve the property key/value pairs belonging to the
* udev device. For every key/value pair, the passed function will be
* called. If the function returns 1, remaning properties will be
* ignored.
*
* Returns: the number of properties passed to the caller, or a negative value on error
**/
int udev_device_get_properties(struct udev_device *udev_device,
int (*cb)(struct udev_device *udev_device, const char *key, const char *value, void *data),
void *data)
{
struct util_name_entry *name_loop;
int count = 0;
if (udev_device == NULL)
return -1;
list_for_each_entry(name_loop, &udev_device->env_list, node) {
count++;
if (cb(udev_device, name_loop->name, name_loop->value, data) != 0)
break;
}
return count;
}
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 != NULL)
return udev_device->driver;
if (util_get_sys_driver(udev_device->udev, udev_device->syspath, driver, sizeof(driver)) < 2)
return NULL;
udev_device->driver = strdup(driver);
return udev_device->driver;
}
dev_t udev_device_get_devnum(struct udev_device *udev_device)
{
if (udev_device == NULL)
return makedev(0, 0);
return udev_device->devnum;
}
const char *udev_device_get_action(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->action;
}
unsigned long long int udev_device_get_seqnum(struct udev_device *udev_device)
{
if (udev_device == NULL)
return 0;
return udev_device->seqnum;
}
const char *udev_device_get_attr_value(struct udev_device *udev_device, const char *attr)
{
struct util_name_entry *name_loop;
char path[UTIL_PATH_SIZE];
char value[UTIL_NAME_SIZE];
struct stat statbuf;
int fd;
ssize_t size;
const char *val = NULL;
/* look for possibly already cached result */
list_for_each_entry(name_loop, &udev_device->attr_list, node) {
if (strcmp(name_loop->name, attr) == 0) {
info(udev_device->udev, "'%s' in cache '%s'\n", attr, name_loop->value);
return name_loop->value;
}
}
util_strlcpy(path, udev_device_get_syspath(udev_device), sizeof(path));
util_strlcat(path, "/", sizeof(path));
util_strlcat(path, attr, sizeof(path));
if (lstat(path, &statbuf) != 0) {
info(udev_device->udev, "stat '%s' failed: %s\n", path, strerror(errno));
goto out;
}
if (S_ISLNK(statbuf.st_mode)) {
/* links return the last element of the target path */
char target[UTIL_NAME_SIZE];
int len;
char *pos;
len = readlink(path, target, sizeof(target));
if (len > 0) {
target[len] = '\0';
pos = strrchr(target, '/');
if (pos != NULL) {
pos = &pos[1];
info(udev_device->udev, "cache '%s' with link value '%s'\n", attr, pos);
val = util_name_list_add(udev_device->udev, &udev_device->attr_list, attr, pos, 0)->value;
}
}
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);
if (fd < 0) {
info(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');
info(udev_device->udev, "'%s' has attribute value '%s'\n", path, value);
val = util_name_list_add(udev_device->udev, &udev_device->attr_list, attr, value, 0)->value;
out:
return val;
}
int device_set_syspath(struct udev_device *udev_device, const char *syspath)
{
const char *pos;
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))];
pos = strrchr(udev_device->syspath, '/');
if (pos == NULL)
return -EINVAL;
udev_device->sysname = &pos[1];
return 0;
}
int device_set_subsystem(struct udev_device *udev_device, const char *subsystem)
{
udev_device->subsystem = strdup(subsystem);
if (udev_device->subsystem == NULL)
return -1;
return 0;
}
int device_set_devname(struct udev_device *udev_device, const char *devname)
{
udev_device->devname = strdup(devname);
if (udev_device->devname == NULL)
return -ENOMEM;
return 0;
}
int device_add_devlink(struct udev_device *udev_device, const char *devlink)
{
if (util_name_list_add(udev_device->udev, &udev_device->link_list, devlink, NULL, 0) == NULL)
return -ENOMEM;
return 0;
}
int device_add_property(struct udev_device *udev_device, const char *key, const char *value)
{
if (util_name_list_add(udev_device->udev, &udev_device->env_list, key, value, 0) == NULL)
return -ENOMEM;
return 0;
}
int device_add_property_from_string(struct udev_device *udev_device, const char *property)
{
char name[UTIL_PATH_SIZE];
char *val;
strncpy(name, property, sizeof(name));
val = strchr(name, '=');
if (val == NULL)
return -1;
val[0] = '\0';
val = &val[1];
if (val[0] == '\0')
val = NULL;
device_add_property(udev_device, name, val);
return 0;
}
int device_set_action(struct udev_device *udev_device, const char *action)
{
udev_device->action = strdup(action);
if (udev_device->action == NULL)
return -ENOMEM;
return 0;
}
int device_set_driver(struct udev_device *udev_device, const char *driver)
{
udev_device->driver = strdup(driver);
if (udev_device->driver == NULL)
return -ENOMEM;
return 0;
}
const char *device_get_devpath_old(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->devpath_old;
}
int device_set_devpath_old(struct udev_device *udev_device, const char *devpath_old)
{
udev_device->devpath_old = strdup(devpath_old);
if (udev_device->devpath_old == NULL)
return -ENOMEM;
return 0;
}
const char *device_get_physdevpath(struct udev_device *udev_device)
{
if (udev_device == NULL)
return NULL;
return udev_device->physdevpath;
}
int device_set_physdevpath(struct udev_device *udev_device, const char *physdevpath)
{
udev_device->physdevpath = strdup(physdevpath);
if (udev_device->physdevpath == NULL)
return -ENOMEM;
return 0;
}
int device_get_timeout(struct udev_device *udev_device)
{
if (udev_device == NULL)
return -1;
return udev_device->timeout;
}
int device_set_timeout(struct udev_device *udev_device, int timeout)
{
udev_device->timeout = timeout;
return 0;
}
int device_set_seqnum(struct udev_device *udev_device, unsigned long long int seqnum)
{
udev_device->seqnum = seqnum;
return 0;
}
int device_set_devnum(struct udev_device *udev_device, dev_t devnum)
{
udev_device->devnum = devnum;
return 0;
}
int device_get_num_fake_partitions(struct udev_device *udev_device)
{
if (udev_device == NULL)
return -1;
return udev_device->num_fake_partitions;
}
int device_set_num_fake_partitions(struct udev_device *udev_device, int num)
{
udev_device->num_fake_partitions = num;
return 0;
}
int device_get_devlink_priority(struct udev_device *udev_device)
{
if (udev_device == NULL)
return -1;
return udev_device->devlink_priority;
}
int device_set_devlink_priority(struct udev_device *udev_device, int prio)
{
udev_device->devlink_priority = prio;
return 0;
}
int device_get_ignore_remove(struct udev_device *udev_device)
{
if (udev_device == NULL)
return -1;
return udev_device->ignore_remove;
}
int device_set_ignore_remove(struct udev_device *udev_device, int ignore)
{
udev_device->ignore_remove = ignore;
return 0;
}