libudev.c revision 33a5cc297680f20e791c792a45fe949f715f5f69
/*
* 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 <sys/stat.h>
#include "libudev.h"
#include "libudev-private.h"
#include "../udev.h"
void udev_log(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, ...)
{
va_list args;
va_start(args, format);
udev->log_fn(udev, priority, file, line, fn, format, args);
va_end(args);
}
static void log_stderr(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, va_list args)
{
static int log = -1;
if (log == -1) {
if (getenv("LIBUDEV_DEBUG") != NULL)
log = 1;
else
log = 0;
}
if (log == 1) {
fprintf(stderr, "libudev: %s: ", fn);
vfprintf(stderr, format, args);
}
}
/* glue to udev logging, needed until udev logging code is "fixed" */
#ifdef USE_LOG
void log_message(int priority, const char *format, ...)
{
va_list args;
va_start(args, format);
log_stderr(NULL, priority, NULL, 0, "", format, args);
va_end(args);
}
#endif
static ssize_t get_subsystem(struct udev *udev, const char *devpath, char *subsystem, size_t size)
{
char path[PATH_SIZE];
ssize_t len;
const char *pos;
strlcpy(path, udev_get_sys_path(udev), sizeof(path));
strlcat(path, devpath, sizeof(path));
strlcat(path, "/subsystem", sizeof(path));
len = readlink(path, path, sizeof(path));
if (len < 0 || len >= (ssize_t) sizeof(path))
return -1;
path[len] = '\0';
pos = strrchr(path, '/');
if (pos == NULL)
return -1;
pos = &pos[1];
return strlcpy(subsystem, pos, size);
}
/**
* udev_new:
*
* Create udev library context.
*
* The initial refcount is 1, and needs to be decremented to
* release the ressources of the udev library context.
*
* Returns: a new udev library context
**/
struct udev *udev_new(void)
{
struct udev *udev;
udev = malloc(sizeof(struct udev));
if (udev == NULL)
return NULL;
memset(udev, 0x00, (sizeof(struct udev)));
udev->refcount = 1;
udev->log_fn = log_stderr;
udev_config_init();
sysfs_init();
log_info(udev, "context %p created\n", udev);
return udev;
}
/**
* udev_ref:
* @udev: udev library context
*
* Take a reference of the udev library context.
*
* Returns: the passed udev library context
**/
struct udev *udev_ref(struct udev *udev)
{
udev->refcount++;
return udev;
}
/**
* udev_unref:
* @udev: udev library context
*
* Drop a reference of the udev library context. If the refcount
* reaches zero, the ressources of the context will be released.
*
**/
void udev_unref(struct udev *udev)
{
udev->refcount--;
if (udev->refcount > 0)
return;
sysfs_cleanup();
log_info(udev, "context %p released\n", udev);
free(udev);
}
/**
* udev_set_log_fn:
* @udev: udev library context
* @log_fn: function to be called for logging messages
*
* The built-in logging, which writes to stderr if the
* LIBUDEV_DEBUG environment variable is set, can be
* overridden by a custom function, to plug log messages
* into the users logging functionality.
*
**/
void udev_set_log_fn(struct udev *udev,
void (*log_fn)(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, va_list args))
{
udev->log_fn = log_fn;
log_info(udev, "custom logging function %p registered\n", udev);
}
/**
* udev_get_sys_path:
* @udev: udev library context
*
* Retrieve the sysfs mount point. The default is "/sys". For
* testing purposes, it can be overridden with the environment
* variable SYSFS_PATH.
*
* Returns: the sys mount point
**/
const char *udev_get_sys_path(struct udev *udev)
{
return sysfs_path;
}
/**
* udev_get_dev_path:
* @udev: udev library context
*
* Retrieve the device directory path. The default value is "/dev",
* the actual value may be overridden in the udev configuration
* file.
*
* Returns: the device directory path
**/
const char *udev_get_dev_path(struct udev *udev)
{
return udev_root;
}
static struct udev_device *device_init(struct udev *udev)
{
struct udev_device *udev_device;
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;
return udev_device;
}
/**
* udev_device_new_from_devpath:
* @udev: udev library context
* @devpath: sys device path
*
* Create new udev device, and fill in information from the sysfs
* device and the udev database entry. The devpath must not contain
* the sysfs mount path, and must contain a leading '/'.
*
* 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_devpath(struct udev *udev, const char *devpath)
{
char path[PATH_SIZE];
struct stat statbuf;
struct udev_device *udev_device;
int err;
strlcpy(path, udev_get_sys_path(udev), sizeof(path));
strlcat(path, devpath, sizeof(path));
if (stat(path, &statbuf) != 0)
return NULL;
if (!S_ISDIR(statbuf.st_mode))
return NULL;
udev_device = device_init(udev);
if (udev_device == NULL)
return NULL;
udev_device->udevice = udev_device_init(NULL);
if (udev_device->udevice == NULL) {
free(udev_device);
return NULL;
}
log_info(udev, "device %p created\n", udev_device);
strlcpy(path, devpath, sizeof(path));
sysfs_resolve_link(path, sizeof(path));
err = udev_db_get_device(udev_device->udevice, path);
if (err >= 0)
log_info(udev, "device %p filled with udev database data\n", udev_device);
log_info(udev, "device %p filled with %s data\n", udev_device, udev_device_get_devpath(udev_device));
return udev_device;
}
/**
* udev_device_get_udev:
*
* 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)
{
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)
{
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)
{
udev_device->refcount--;
if (udev_device->refcount > 0)
return;
udev_device_cleanup(udev_device->udevice);
free(udev_device);
}
/**
* udev_device_get_devpath:
* @udev_device: udev device
*
* Retrieve the sys path of the udev device. The path does not contain
* the sys mount point.
*
* Returns: the sys path of the udev device
**/
const char *udev_device_get_devpath(struct udev_device *udev_device)
{
return udev_device->udevice->dev->devpath;
}
/**
* udev_device_get_devname:
* @udev_device: udev device
*
* Retrieve the device node file name belonging to the udev device.
* The path does not contain the device directory, and does not contain
* a leading '/'.
*
* 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->udevice->name[0] == '\0')
return NULL;
return udev_device->udevice->name;
}
/**
* 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)
{
struct sysfs_device *dev = udev_device->udevice->dev;
if (dev->subsystem[0] != '\0')
return dev->subsystem;
if (get_subsystem(udev_device->udev, dev->devpath,
dev->subsystem, sizeof(dev->subsystem)) < 2)
return NULL;
return dev->subsystem;
}
/**
* 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. If the function returns 1,
* remaning device links will be ignored. The device link path
* does not contain the device directory, and does not contain
* a leading '/'.
*
* 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 name_entry *name_loop;
int count = 0;
list_for_each_entry(name_loop, &udev_device->udevice->symlink_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 name_entry *name_loop;
int count = 0;
list_for_each_entry(name_loop, &udev_device->udevice->env_list, node) {
char name[PATH_SIZE];
char *val;
strncpy(name, name_loop->name, PATH_SIZE);
name[PATH_SIZE-1] = '\0';
val = strchr(name, '=');
if (val == NULL)
continue;
val[0] = '\0';
val = &val[1];
if (cb(udev_device, name, val, data) != 0)
break;
}
return count;
}
static int devices_scan_subsystem(struct udev *udev,
const char *basedir, const char *subsystem, const char *subdir,
struct list_head *device_list)
{
char path[PATH_SIZE];
DIR *dir;
struct dirent *dent;
size_t len;
len = strlcpy(path, udev_get_sys_path(udev), sizeof(path));
strlcat(path, basedir, sizeof(path));
strlcat(path, "/", sizeof(path));
strlcat(path, subsystem, sizeof(path));
if (subdir != NULL)
strlcat(path, subdir, sizeof(path));
dir = opendir(path);
if (dir == NULL)
return -1;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
char devpath[PATH_SIZE];
if (dent->d_name[0] == '.')
continue;
strlcpy(devpath, &path[len], sizeof(devpath));
strlcat(devpath, "/", sizeof(devpath));
strlcat(devpath, dent->d_name, sizeof(devpath));
sysfs_resolve_link(devpath, sizeof(devpath));
name_list_add(device_list, devpath, 1);
}
closedir(dir);
return 0;
}
static int devices_scan_subsystems(struct udev *udev,
const char *basedir, const char *subsystem, const char *subdir,
struct list_head *device_list)
{
char path[PATH_SIZE];
DIR *dir;
struct dirent *dent;
if (subsystem != NULL)
return devices_scan_subsystem(udev, basedir, subsystem, subdir, device_list);
strlcpy(path, udev_get_sys_path(udev), sizeof(path));
strlcat(path, basedir, sizeof(path));
dir = opendir(path);
if (dir == NULL)
return -1;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
if (dent->d_name[0] == '.')
continue;
devices_scan_subsystem(udev, basedir, dent->d_name, subdir, device_list);
}
closedir(dir);
return 0;
}
static int devices_delay(struct udev *udev, const char *devpath)
{
static const char *delay_device_list[] = {
"/block/md",
"/block/dm-",
NULL
};
int i;
for (i = 0; delay_device_list[i] != NULL; i++) {
if (strstr(devpath, delay_device_list[i]) != NULL) {
log_info(udev, "delaying: %s\n", devpath);
return 1;
}
}
return 0;
}
static int devices_call(struct udev *udev, const char *devpath,
int (*cb)(struct udev *udev,
const char *devpath, const char *subsystem, const char *name,
void *data),
void *data,
int *cb_rc)
{
char subsystem[NAME_SIZE];
const char *name;
name = strrchr(devpath, '/');
if (name == NULL)
return -1;
name++;
if (get_subsystem(udev, devpath, subsystem, sizeof(subsystem)) < 2)
return -1;
*cb_rc = cb(udev, devpath, subsystem, name, data);
return 0;
}
/**
* udev_devices_enumerate:
* @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_devices_enumerate(struct udev *udev, const char *subsystem,
int (*cb)(struct udev *udev,
const char *devpath, const char *subsystem, const char *name, void *data),
void *data)
{
char base[PATH_SIZE];
struct stat statbuf;
struct list_head device_list;
struct name_entry *loop_device;
struct name_entry *tmp_device;
int cb_rc = 0;
int count = 0;
INIT_LIST_HEAD(&device_list);
/* if we have /sys/subsystem/, forget all the old stuff */
strlcpy(base, sysfs_path, sizeof(base));
strlcat(base, "/subsystem", sizeof(base));
if (stat(base, &statbuf) == 0) {
devices_scan_subsystems(udev, "/subsystem", subsystem, "/devices", &device_list);
} else {
devices_scan_subsystems(udev, "/bus", subsystem, "/devices", &device_list);
devices_scan_subsystems(udev, "/class", subsystem, NULL, &device_list);
}
list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
if (devices_delay(udev, loop_device->name))
continue;
if (cb_rc == 0)
if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
count++;
list_del(&loop_device->node);
free(loop_device);
}
/* handle remaining delayed devices */
list_for_each_entry_safe(loop_device, tmp_device, &device_list, node) {
if (cb_rc == 0)
if (devices_call(udev, loop_device->name, cb, data, &cb_rc) == 0)
count++;
list_del(&loop_device->node);
free(loop_device);
}
return count;
}