libudev.c revision baa30fbc2c04b23209d0b8fb3c86cd15ef9ea81a
/*
* 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 <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <time.h>
#include "libudev.h"
#include "libudev-private.h"
/**
* SECTION:libudev
* @short_description: libudev context
*
* The context contains the default values read from the udev config file,
* and is passed to all library operations.
*/
/**
* udev:
*
* Opaque object representing the library context.
*/
struct udev {
int refcount;
void (*log_fn)(struct udev *udev,
int priority, const char *file, int line, const char *fn,
const char *format, va_list args);
void *userdata;
char *sys_path;
char *dev_path;
char *rules_path[4];
unsigned long long rules_path_ts[4];
int rules_path_count;
char *run_path;
struct udev_list properties_list;
int log_priority;
};
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)
{
fprintf(stderr, "libudev: %s: ", fn);
vfprintf(stderr, format, args);
}
/**
* udev_get_userdata:
* @udev: udev library context
*
* Retrieve stored data pointer from library context. This might be useful
* to access from callbacks like a custom logging function.
*
* Returns: stored userdata
**/
_public_ void *udev_get_userdata(struct udev *udev)
{
if (udev == NULL)
return NULL;
return udev->userdata;
}
/**
* udev_set_userdata:
* @udev: udev library context
* @userdata: data pointer
*
* Store custom @userdata in the library context.
**/
_public_ void udev_set_userdata(struct udev *udev, void *userdata)
{
if (udev == NULL)
return;
udev->userdata = userdata;
}
static char *set_value(char **s, const char *v)
{
free(*s);
*s = strdup(v);
util_remove_trailing_chars(*s, '/');
return *s;
}
/**
* udev_new:
*
* Create udev library context. This reads the udev configuration
* file, and fills in the default values.
*
* The initial refcount is 1, and needs to be decremented to
* release the resources of the udev library context.
*
* Returns: a new udev library context
**/
_public_ struct udev *udev_new(void)
{
struct udev *udev;
const char *env;
char *config_file = NULL;
FILE *f;
udev = calloc(1, sizeof(struct udev));
if (udev == NULL)
return NULL;
udev->refcount = 1;
udev->log_fn = log_stderr;
udev->log_priority = LOG_ERR;
udev_list_init(udev, &udev->properties_list, true);
/* custom config file */
env = getenv("UDEV_CONFIG_FILE");
if (env != NULL) {
if (set_value(&config_file, env) == NULL)
goto err;
udev_add_property(udev, "UDEV_CONFIG_FILE", config_file);
}
/* default config file */
if (config_file == NULL)
config_file = strdup(SYSCONFDIR "/udev/udev.conf");
if (config_file == NULL)
goto err;
f = fopen(config_file, "re");
if (f != NULL) {
char line[UTIL_LINE_SIZE];
int line_nr = 0;
while (fgets(line, sizeof(line), f)) {
size_t len;
char *key;
char *val;
line_nr++;
/* find key */
key = line;
while (isspace(key[0]))
key++;
/* comment or empty line */
if (key[0] == '#' || key[0] == '\0')
continue;
/* split key/value */
val = strchr(key, '=');
if (val == NULL) {
err(udev, "missing <key>=<value> in '%s'[%i], skip line\n", config_file, line_nr);
continue;
}
val[0] = '\0';
val++;
/* find value */
while (isspace(val[0]))
val++;
/* terminate key */
len = strlen(key);
if (len == 0)
continue;
while (isspace(key[len-1]))
len--;
key[len] = '\0';
/* terminate value */
len = strlen(val);
if (len == 0)
continue;
while (isspace(val[len-1]))
len--;
val[len] = '\0';
if (len == 0)
continue;
/* unquote */
if (val[0] == '"' || val[0] == '\'') {
if (val[len-1] != val[0]) {
err(udev, "inconsistent quoting in '%s'[%i], skip line\n", config_file, line_nr);
continue;
}
val[len-1] = '\0';
val++;
}
if (strcmp(key, "udev_log") == 0) {
udev_set_log_priority(udev, util_log_priority(val));
continue;
}
if (strcmp(key, "udev_root") == 0) {
set_value(&udev->dev_path, val);
continue;
}
if (strcmp(key, "udev_run") == 0) {
set_value(&udev->run_path, val);
continue;
}
if (strcmp(key, "udev_sys") == 0) {
set_value(&udev->sys_path, val);
continue;
}
if (strcmp(key, "udev_rules") == 0) {
set_value(&udev->rules_path[0], val);
udev->rules_path_count = 1;
continue;
}
}
fclose(f);
}
/* environment overrides config */
env = getenv("UDEV_LOG");
if (env != NULL)
udev_set_log_priority(udev, util_log_priority(env));
/* set defaults */
if (udev->dev_path == NULL)
if (set_value(&udev->dev_path, "/dev") == NULL)
goto err;
if (udev->sys_path == NULL)
if (set_value(&udev->sys_path, "/sys") == NULL)
goto err;
if (udev->run_path == NULL)
if (set_value(&udev->run_path, "/run/udev") == NULL)
goto err;
if (udev->rules_path[0] == NULL) {
/* /usr/lib/udev -- system rules */
udev->rules_path[0] = strdup(UDEVLIBEXECDIR "/rules.d");
if (!udev->rules_path[0])
goto err;
/* /run/udev -- runtime rules */
if (asprintf(&udev->rules_path[2], "%s/rules.d", udev->run_path) < 0)
goto err;
/* /etc/udev -- local administration rules */
udev->rules_path[1] = strdup(SYSCONFDIR "/udev/rules.d");
if (!udev->rules_path[1])
goto err;
udev->rules_path_count = 3;
}
free(config_file);
return udev;
err:
free(config_file);
err(udev, "context creation failed\n");
udev_unref(udev);
return NULL;
}
/**
* udev_ref:
* @udev: udev library context
*
* Take a reference of the udev library context.
*
* Returns: the passed udev library context
**/
_public_ struct udev *udev_ref(struct udev *udev)
{
if (udev == NULL)
return NULL;
udev->refcount++;
return udev;
}
/**
* udev_unref:
* @udev: udev library context
*
* Drop a reference of the udev library context. If the refcount
* reaches zero, the resources of the context will be released.
*
**/
_public_ void udev_unref(struct udev *udev)
{
if (udev == NULL)
return;
udev->refcount--;
if (udev->refcount > 0)
return;
udev_list_cleanup(&udev->properties_list);
free(udev->dev_path);
free(udev->sys_path);
free(udev->rules_path[0]);
free(udev->rules_path[1]);
free(udev->rules_path[2]);
free(udev->run_path);
free(udev);
}
/**
* udev_set_log_fn:
* @udev: udev library context
* @log_fn: function to be called for logging messages
*
* The built-in logging writes to stderr. It can be
* overridden by a custom function, to plug log messages
* into the users' logging functionality.
*
**/
_public_ 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;
dbg(udev, "custom logging function %p registered\n", log_fn);
}
/**
* udev_get_log_priority:
* @udev: udev library context
*
* The initial logging priority is read from the udev config file
* at startup.
*
* Returns: the current logging priority
**/
_public_ int udev_get_log_priority(struct udev *udev)
{
return udev->log_priority;
}
/**
* udev_set_log_priority:
* @udev: udev library context
* @priority: the new logging priority
*
* Set the current logging priority. The value controls which messages
* are logged.
**/
_public_ void udev_set_log_priority(struct udev *udev, int priority)
{
char num[32];
udev->log_priority = priority;
snprintf(num, sizeof(num), "%u", udev->log_priority);
udev_add_property(udev, "UDEV_LOG", num);
}
int udev_get_rules_path(struct udev *udev, char **path[], unsigned long long *stamp_usec[])
{
*path = udev->rules_path;
if (stamp_usec)
*stamp_usec = udev->rules_path_ts;
return udev->rules_path_count;
}
/**
* 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 udev_sys=
* in the udev configuration file.
*
* Returns: the sys mount point
**/
_public_ const char *udev_get_sys_path(struct udev *udev)
{
if (udev == NULL)
return NULL;
return udev->sys_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
**/
_public_ const char *udev_get_dev_path(struct udev *udev)
{
if (udev == NULL)
return NULL;
return udev->dev_path;
}
/**
* udev_get_run_path:
* @udev: udev library context
*
* Retrieve the udev runtime directory path. The default is "/run/udev".
*
* Returns: the runtime directory path
**/
_public_ const char *udev_get_run_path(struct udev *udev)
{
if (udev == NULL)
return NULL;
return udev->run_path;
}
struct udev_list_entry *udev_add_property(struct udev *udev, const char *key, const char *value)
{
if (value == NULL) {
struct udev_list_entry *list_entry;
list_entry = udev_get_properties_list_entry(udev);
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->properties_list, key, value);
}
struct udev_list_entry *udev_get_properties_list_entry(struct udev *udev)
{
return udev_list_get_entry(&udev->properties_list);
}