libudev-enumerate.c revision 21dbe43aece5b6fc87860de175f067b56649e7d1
/*
* 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 <errno.h>
#include <string.h>
#include <dirent.h>
#include <fnmatch.h>
#include <stdbool.h>
#include <sys/stat.h>
#include <sys/param.h>
#include "libudev.h"
#include "libudev-private.h"
/**
* SECTION:libudev-enumerate
* @short_description: lookup and sort sys devices
*
* Lookup devices in the sys filesystem, filter devices by properties,
* and return a sorted list of devices.
*/
struct syspath {
char *syspath;
size_t len;
};
/**
* udev_enumerate:
*
* Opaque object representing one device lookup/sort context.
*/
struct udev_enumerate {
struct udev *udev;
int refcount;
struct udev_list sysattr_match_list;
struct udev_list sysattr_nomatch_list;
struct udev_list subsystem_match_list;
struct udev_list subsystem_nomatch_list;
struct udev_list sysname_match_list;
struct udev_list properties_match_list;
struct udev_list tags_match_list;
struct udev_device *parent_match;
struct udev_list devices_list;
struct syspath *devices;
unsigned int devices_cur;
unsigned int devices_max;
bool devices_uptodate:1;
bool match_is_initialized;
};
/**
* udev_enumerate_new:
* @udev: udev library context
*
* Create an enumeration context to scan /sys.
*
* Returns: an enumeration context.
**/
_public_ struct udev_enumerate *udev_enumerate_new(struct udev *udev)
{
struct udev_enumerate *udev_enumerate;
udev_enumerate = calloc(1, sizeof(struct udev_enumerate));
if (udev_enumerate == NULL)
return NULL;
udev_enumerate->refcount = 1;
udev_enumerate->udev = udev;
udev_list_init(udev, &udev_enumerate->sysattr_match_list, false);
udev_list_init(udev, &udev_enumerate->sysattr_nomatch_list, false);
udev_list_init(udev, &udev_enumerate->subsystem_match_list, true);
udev_list_init(udev, &udev_enumerate->subsystem_nomatch_list, true);
udev_list_init(udev, &udev_enumerate->sysname_match_list, true);
udev_list_init(udev, &udev_enumerate->properties_match_list, false);
udev_list_init(udev, &udev_enumerate->tags_match_list, true);
udev_list_init(udev, &udev_enumerate->devices_list, false);
return udev_enumerate;
}
/**
* udev_enumerate_ref:
* @udev_enumerate: context
*
* Take a reference of a enumeration context.
*
* Returns: the passed enumeration context
**/
_public_ struct udev_enumerate *udev_enumerate_ref(struct udev_enumerate *udev_enumerate)
{
if (udev_enumerate == NULL)
return NULL;
udev_enumerate->refcount++;
return udev_enumerate;
}
/**
* udev_enumerate_unref:
* @udev_enumerate: context
*
* Drop a reference of an enumeration context. If the refcount reaches zero,
* all resources of the enumeration context will be released.
**/
_public_ void udev_enumerate_unref(struct udev_enumerate *udev_enumerate)
{
unsigned int i;
if (udev_enumerate == NULL)
return;
udev_enumerate->refcount--;
if (udev_enumerate->refcount > 0)
return;
udev_list_cleanup(&udev_enumerate->sysattr_match_list);
udev_list_cleanup(&udev_enumerate->sysattr_nomatch_list);
udev_list_cleanup(&udev_enumerate->subsystem_match_list);
udev_list_cleanup(&udev_enumerate->subsystem_nomatch_list);
udev_list_cleanup(&udev_enumerate->sysname_match_list);
udev_list_cleanup(&udev_enumerate->properties_match_list);
udev_list_cleanup(&udev_enumerate->tags_match_list);
udev_device_unref(udev_enumerate->parent_match);
udev_list_cleanup(&udev_enumerate->devices_list);
for (i = 0; i < udev_enumerate->devices_cur; i++)
free(udev_enumerate->devices[i].syspath);
free(udev_enumerate->devices);
free(udev_enumerate);
}
/**
* udev_enumerate_get_udev:
* @udev_enumerate: context
*
* Get the udev library context.
*
* Returns: a pointer to the context.
*/
_public_ struct udev *udev_enumerate_get_udev(struct udev_enumerate *udev_enumerate)
{
if (udev_enumerate == NULL)
return NULL;
return udev_enumerate->udev;
}
static int syspath_add(struct udev_enumerate *udev_enumerate, const char *syspath)
{
char *path;
struct syspath *entry;
/* double array size if needed */
if (udev_enumerate->devices_cur >= udev_enumerate->devices_max) {
struct syspath *buf;
unsigned int add;
add = udev_enumerate->devices_max;
if (add < 1024)
add = 1024;
buf = realloc(udev_enumerate->devices, (udev_enumerate->devices_max + add) * sizeof(struct syspath));
if (buf == NULL)
return -ENOMEM;
udev_enumerate->devices = buf;
udev_enumerate->devices_max += add;
}
path = strdup(syspath);
if (path == NULL)
return -ENOMEM;
entry = &udev_enumerate->devices[udev_enumerate->devices_cur];
entry->syspath = path;
entry->len = strlen(path);
udev_enumerate->devices_cur++;
udev_enumerate->devices_uptodate = false;
return 0;
}
static int syspath_cmp(const void *p1, const void *p2)
{
const struct syspath *path1 = p1;
const struct syspath *path2 = p2;
size_t len;
int ret;
len = MIN(path1->len, path2->len);
ret = memcmp(path1->syspath, path2->syspath, len);
if (ret == 0) {
if (path1->len < path2->len)
ret = -1;
else if (path1->len > path2->len)
ret = 1;
}
return ret;
}
/* For devices that should be moved to the absolute end of the list */
static bool devices_delay_end(struct udev *udev, const char *syspath)
{
static const char *delay_device_list[] = {
"/block/md",
"/block/dm-",
NULL
};
int i;
for (i = 0; delay_device_list[i] != NULL; i++) {
if (strstr(syspath + strlen("/sys"), delay_device_list[i]) != NULL)
return true;
}
return false;
}
/* For devices that should just be moved a little bit later, just
* before the point where some common path prefix changes. Returns the
* number of characters that make up that common prefix */
static size_t devices_delay_later(struct udev *udev, const char *syspath)
{
const char *c;
/* For sound cards the control device must be enumerated last
* to make sure it's the final device node that gets ACLs
* applied. Applications rely on this fact and use ACL changes
* on the control node as an indicator that the ACL change of
* the entire sound card completed. The kernel makes this
* guarantee when creating those devices, and hence we should
* too when enumerating them. */
if ((c = strstr(syspath, "/sound/card"))) {
c += 11;
c += strcspn(c, "/");
if (startswith(c, "/controlC"))
return c - syspath + 1;
}
return 0;
}
/**
* udev_enumerate_get_list_entry:
* @udev_enumerate: context
*
* Get the first entry of the sorted list of device paths.
*
* Returns: a udev_list_entry.
*/
_public_ struct udev_list_entry *udev_enumerate_get_list_entry(struct udev_enumerate *udev_enumerate)
{
if (udev_enumerate == NULL)
return NULL;
if (!udev_enumerate->devices_uptodate) {
unsigned int i;
unsigned int max;
struct syspath *prev = NULL, *move_later = NULL;
size_t move_later_prefix = 0;
udev_list_cleanup(&udev_enumerate->devices_list);
qsort(udev_enumerate->devices, udev_enumerate->devices_cur, sizeof(struct syspath), syspath_cmp);
max = udev_enumerate->devices_cur;
for (i = 0; i < max; i++) {
struct syspath *entry = &udev_enumerate->devices[i];
/* skip duplicated entries */
if (prev != NULL &&
entry->len == prev->len &&
memcmp(entry->syspath, prev->syspath, entry->len) == 0)
continue;
prev = entry;
/* skip to be delayed devices, and add them to the end of the list */
if (devices_delay_end(udev_enumerate->udev, entry->syspath)) {
syspath_add(udev_enumerate, entry->syspath);
/* need to update prev here for the case realloc() gives a different address */
prev = &udev_enumerate->devices[i];
continue;
}
/* skip to be delayed devices, and move the to
* the point where the prefix changes. We can
* only move one item at a time. */
if (!move_later) {
move_later_prefix = devices_delay_later(udev_enumerate->udev, entry->syspath);
if (move_later_prefix > 0) {
move_later = entry;
continue;
}
}
if (move_later &&
strncmp(entry->syspath, move_later->syspath, move_later_prefix) != 0) {
udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
move_later = NULL;
}
udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
}
if (move_later)
udev_list_entry_add(&udev_enumerate->devices_list, move_later->syspath, NULL);
/* add and cleanup delayed devices from end of list */
for (i = max; i < udev_enumerate->devices_cur; i++) {
struct syspath *entry = &udev_enumerate->devices[i];
udev_list_entry_add(&udev_enumerate->devices_list, entry->syspath, NULL);
free(entry->syspath);
}
udev_enumerate->devices_cur = max;
udev_enumerate->devices_uptodate = true;
}
return udev_list_get_entry(&udev_enumerate->devices_list);
}
/**
* udev_enumerate_add_match_subsystem:
* @udev_enumerate: context
* @subsystem: filter for a subsystem of the device to include in the list
*
* Match only devices belonging to a certain kernel subsystem.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (subsystem == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->subsystem_match_list, subsystem, NULL) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_enumerate_add_nomatch_subsystem:
* @udev_enumerate: context
* @subsystem: filter for a subsystem of the device to exclude from the list
*
* Match only devices not belonging to a certain kernel subsystem.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_nomatch_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (subsystem == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->subsystem_nomatch_list, subsystem, NULL) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_enumerate_add_match_sysattr:
* @udev_enumerate: context
* @sysattr: filter for a sys attribute at the device to include in the list
* @value: optional value of the sys attribute
*
* Match only devices with a certain /sys device attribute.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (sysattr == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->sysattr_match_list, sysattr, value) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_enumerate_add_nomatch_sysattr:
* @udev_enumerate: context
* @sysattr: filter for a sys attribute at the device to exclude from the list
* @value: optional value of the sys attribute
*
* Match only devices not having a certain /sys device attribute.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_nomatch_sysattr(struct udev_enumerate *udev_enumerate, const char *sysattr, const char *value)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (sysattr == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->sysattr_nomatch_list, sysattr, value) == NULL)
return -ENOMEM;
return 0;
}
static int match_sysattr_value(struct udev_device *dev, const char *sysattr, const char *match_val)
{
const char *val = NULL;
bool match = false;
val = udev_device_get_sysattr_value(dev, sysattr);
if (val == NULL)
goto exit;
if (match_val == NULL) {
match = true;
goto exit;
}
if (fnmatch(match_val, val, 0) == 0) {
match = true;
goto exit;
}
exit:
return match;
}
/**
* udev_enumerate_add_match_property:
* @udev_enumerate: context
* @property: filter for a property of the device to include in the list
* @value: value of the property
*
* Match only devices with a certain property.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_property(struct udev_enumerate *udev_enumerate, const char *property, const char *value)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (property == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->properties_match_list, property, value) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_enumerate_add_match_tag:
* @udev_enumerate: context
* @tag: filter for a tag of the device to include in the list
*
* Match only devices with a certain tag.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_tag(struct udev_enumerate *udev_enumerate, const char *tag)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (tag == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->tags_match_list, tag, NULL) == NULL)
return -ENOMEM;
return 0;
}
/**
* udev_enumerate_add_match_parent:
* @udev_enumerate: context
* @parent: parent device where to start searching
*
* Return the devices on the subtree of one given device. The parent
* itself is included in the list.
*
* A reference for the device is held until the udev_enumerate context
* is cleaned up.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *parent)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (parent == NULL)
return 0;
if (udev_enumerate->parent_match != NULL)
udev_device_unref(udev_enumerate->parent_match);
udev_enumerate->parent_match = udev_device_ref(parent);
return 0;
}
/**
* udev_enumerate_add_match_is_initialized:
* @udev_enumerate: context
*
* Match only devices which udev has set up already. This makes
* sure, that the device node permissions and context are properly set
* and that network devices are fully renamed.
*
* Usually, devices which are found in the kernel but not already
* handled by udev, have still pending events. Services should subscribe
* to monitor events and wait for these devices to become ready, instead
* of using uninitialized devices.
*
* For now, this will not affect devices which do not have a device node
* and are not network interfaces.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_is_initialized(struct udev_enumerate *udev_enumerate)
{
if (udev_enumerate == NULL)
return -EINVAL;
udev_enumerate->match_is_initialized = true;
return 0;
}
/**
* udev_enumerate_add_match_sysname:
* @udev_enumerate: context
* @sysname: filter for the name of the device to include in the list
*
* Match only devices with a given /sys device name.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
{
if (udev_enumerate == NULL)
return -EINVAL;
if (sysname == NULL)
return 0;
if (udev_list_entry_add(&udev_enumerate->sysname_match_list, sysname, NULL) == NULL)
return -ENOMEM;
return 0;
}
static bool match_sysattr(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
{
struct udev_list_entry *list_entry;
/* skip list */
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_nomatch_list)) {
if (match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
udev_list_entry_get_value(list_entry)))
return false;
}
/* include list */
if (udev_list_get_entry(&udev_enumerate->sysattr_match_list) != NULL) {
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysattr_match_list)) {
/* anything that does not match, will make it FALSE */
if (!match_sysattr_value(dev, udev_list_entry_get_name(list_entry),
udev_list_entry_get_value(list_entry)))
return false;
}
return true;
}
return true;
}
static bool match_property(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
{
struct udev_list_entry *list_entry;
bool match = false;
/* no match always matches */
if (udev_list_get_entry(&udev_enumerate->properties_match_list) == NULL)
return true;
/* loop over matches */
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->properties_match_list)) {
const char *match_key = udev_list_entry_get_name(list_entry);
const char *match_value = udev_list_entry_get_value(list_entry);
struct udev_list_entry *property_entry;
/* loop over device properties */
udev_list_entry_foreach(property_entry, udev_device_get_properties_list_entry(dev)) {
const char *dev_key = udev_list_entry_get_name(property_entry);
const char *dev_value = udev_list_entry_get_value(property_entry);
if (fnmatch(match_key, dev_key, 0) != 0)
continue;
if (match_value == NULL && dev_value == NULL) {
match = true;
goto out;
}
if (match_value == NULL || dev_value == NULL)
continue;
if (fnmatch(match_value, dev_value, 0) == 0) {
match = true;
goto out;
}
}
}
out:
return match;
}
static bool match_tag(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
{
struct udev_list_entry *list_entry;
/* no match always matches */
if (udev_list_get_entry(&udev_enumerate->tags_match_list) == NULL)
return true;
/* loop over matches */
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list))
if (!udev_device_has_tag(dev, udev_list_entry_get_name(list_entry)))
return false;
return true;
}
static bool match_parent(struct udev_enumerate *udev_enumerate, struct udev_device *dev)
{
if (udev_enumerate->parent_match == NULL)
return true;
return startswith(udev_device_get_devpath(dev), udev_device_get_devpath(udev_enumerate->parent_match));
}
static bool match_sysname(struct udev_enumerate *udev_enumerate, const char *sysname)
{
struct udev_list_entry *list_entry;
if (udev_list_get_entry(&udev_enumerate->sysname_match_list) == NULL)
return true;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->sysname_match_list)) {
if (fnmatch(udev_list_entry_get_name(list_entry), sysname, 0) != 0)
continue;
return true;
}
return false;
}
static int scan_dir_and_add_devices(struct udev_enumerate *udev_enumerate,
const char *basedir, const char *subdir1, const char *subdir2)
{
char path[UTIL_PATH_SIZE];
size_t l;
char *s;
DIR *dir;
struct dirent *dent;
s = path;
l = util_strpcpyl(&s, sizeof(path), "/sys/", basedir, NULL);
if (subdir1 != NULL)
l = util_strpcpyl(&s, l, "/", subdir1, NULL);
if (subdir2 != NULL)
util_strpcpyl(&s, l, "/", subdir2, NULL);
dir = opendir(path);
if (dir == NULL)
return -ENOENT;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
char syspath[UTIL_PATH_SIZE];
struct udev_device *dev;
if (dent->d_name[0] == '.')
continue;
if (!match_sysname(udev_enumerate, dent->d_name))
continue;
util_strscpyl(syspath, sizeof(syspath), path, "/", dent->d_name, NULL);
dev = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
if (dev == NULL)
continue;
if (udev_enumerate->match_is_initialized) {
/*
* All devices with a device node or network interfaces
* possibly need udev to adjust the device node permission
* or context, or rename the interface before it can be
* reliably used from other processes.
*
* For now, we can only check these types of devices, we
* might not store a database, and have no way to find out
* for all other types of devices.
*/
if (!udev_device_get_is_initialized(dev) &&
(major(udev_device_get_devnum(dev)) > 0 || udev_device_get_ifindex(dev) > 0))
goto nomatch;
}
if (!match_parent(udev_enumerate, dev))
goto nomatch;
if (!match_tag(udev_enumerate, dev))
goto nomatch;
if (!match_property(udev_enumerate, dev))
goto nomatch;
if (!match_sysattr(udev_enumerate, dev))
goto nomatch;
syspath_add(udev_enumerate, udev_device_get_syspath(dev));
nomatch:
udev_device_unref(dev);
}
closedir(dir);
return 0;
}
static bool match_subsystem(struct udev_enumerate *udev_enumerate, const char *subsystem)
{
struct udev_list_entry *list_entry;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_nomatch_list)) {
if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
return false;
}
if (udev_list_get_entry(&udev_enumerate->subsystem_match_list) != NULL) {
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->subsystem_match_list)) {
if (fnmatch(udev_list_entry_get_name(list_entry), subsystem, 0) == 0)
return true;
}
return false;
}
return true;
}
static int scan_dir(struct udev_enumerate *udev_enumerate, const char *basedir, const char *subdir, const char *subsystem)
{
char path[UTIL_PATH_SIZE];
DIR *dir;
struct dirent *dent;
util_strscpyl(path, sizeof(path), "/sys/", basedir, NULL);
dir = opendir(path);
if (dir == NULL)
return -1;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
if (dent->d_name[0] == '.')
continue;
if (!match_subsystem(udev_enumerate, subsystem != NULL ? subsystem : dent->d_name))
continue;
scan_dir_and_add_devices(udev_enumerate, basedir, dent->d_name, subdir);
}
closedir(dir);
return 0;
}
/**
* udev_enumerate_add_syspath:
* @udev_enumerate: context
* @syspath: path of a device
*
* Add a device to the list of devices, to retrieve it back sorted in dependency order.
*
* Returns: 0 on success, otherwise a negative error value.
*/
_public_ int udev_enumerate_add_syspath(struct udev_enumerate *udev_enumerate, const char *syspath)
{
struct udev_device *udev_device;
if (udev_enumerate == NULL)
return -EINVAL;
if (syspath == NULL)
return 0;
/* resolve to real syspath */
udev_device = udev_device_new_from_syspath(udev_enumerate->udev, syspath);
if (udev_device == NULL)
return -EINVAL;
syspath_add(udev_enumerate, udev_device_get_syspath(udev_device));
udev_device_unref(udev_device);
return 0;
}
static int scan_devices_tags(struct udev_enumerate *udev_enumerate)
{
struct udev_list_entry *list_entry;
/* scan only tagged devices, use tags reverse-index, instead of searching all devices in /sys */
udev_list_entry_foreach(list_entry, udev_list_get_entry(&udev_enumerate->tags_match_list)) {
DIR *dir;
struct dirent *dent;
char path[UTIL_PATH_SIZE];
util_strscpyl(path, sizeof(path), "/run/udev/tags/", udev_list_entry_get_name(list_entry), NULL);
dir = opendir(path);
if (dir == NULL)
continue;
for (dent = readdir(dir); dent != NULL; dent = readdir(dir)) {
struct udev_device *dev;
if (dent->d_name[0] == '.')
continue;
dev = udev_device_new_from_id_filename(udev_enumerate->udev, dent->d_name);
if (dev == NULL)
continue;
if (!match_subsystem(udev_enumerate, udev_device_get_subsystem(dev)))
goto nomatch;
if (!match_sysname(udev_enumerate, udev_device_get_sysname(dev)))
goto nomatch;
if (!match_parent(udev_enumerate, dev))
goto nomatch;
if (!match_property(udev_enumerate, dev))
goto nomatch;
if (!match_sysattr(udev_enumerate, dev))
goto nomatch;
syspath_add(udev_enumerate, udev_device_get_syspath(dev));
nomatch:
udev_device_unref(dev);
}
closedir(dir);
}
return 0;
}
static int parent_add_child(struct udev_enumerate *enumerate, const char *path)
{
struct udev_device *dev;
dev = udev_device_new_from_syspath(enumerate->udev, path);
if (dev == NULL)
return -ENODEV;
if (!match_subsystem(enumerate, udev_device_get_subsystem(dev)))
return 0;
if (!match_sysname(enumerate, udev_device_get_sysname(dev)))
return 0;
if (!match_property(enumerate, dev))
return 0;
if (!match_sysattr(enumerate, dev))
return 0;
syspath_add(enumerate, udev_device_get_syspath(dev));
udev_device_unref(dev);
return 1;
}
static int parent_crawl_children(struct udev_enumerate *enumerate, const char *path, int maxdepth)
{
DIR *d;
struct dirent *dent;
d = opendir(path);
if (d == NULL)
return -errno;
for (dent = readdir(d); dent != NULL; dent = readdir(d)) {
char *child;
if (dent->d_name[0] == '.')
continue;
if (dent->d_type != DT_DIR)
continue;
if (asprintf(&child, "%s/%s", path, dent->d_name) < 0)
continue;
parent_add_child(enumerate, child);
if (maxdepth > 0)
parent_crawl_children(enumerate, child, maxdepth-1);
free(child);
}
closedir(d);
return 0;
}
static int scan_devices_children(struct udev_enumerate *enumerate)
{
const char *path;
path = udev_device_get_syspath(enumerate->parent_match);
parent_add_child(enumerate, path);
return parent_crawl_children(enumerate, path, 256);
}
static int scan_devices_all(struct udev_enumerate *udev_enumerate)
{
struct stat statbuf;
if (stat("/sys/subsystem", &statbuf) == 0) {
/* we have /subsystem/, forget all the old stuff */
scan_dir(udev_enumerate, "subsystem", "devices", NULL);
} else {
scan_dir(udev_enumerate, "bus", "devices", NULL);
scan_dir(udev_enumerate, "class", NULL, NULL);
}
return 0;
}
/**
* udev_enumerate_scan_devices:
* @udev_enumerate: udev enumeration context
*
* Scan /sys for all devices which match the given filters. No matches
* will return all currently available devices.
*
* Returns: 0 on success, otherwise a negative error value.
**/
_public_ int udev_enumerate_scan_devices(struct udev_enumerate *udev_enumerate)
{
if (udev_enumerate == NULL)
return -EINVAL;
/* efficiently lookup tags only, we maintain a reverse-index */
if (udev_list_get_entry(&udev_enumerate->tags_match_list) != NULL)
return scan_devices_tags(udev_enumerate);
/* walk the subtree of one parent device only */
if (udev_enumerate->parent_match != NULL)
return scan_devices_children(udev_enumerate);
/* scan devices of all subsystems */
return scan_devices_all(udev_enumerate);
}
/**
* udev_enumerate_scan_subsystems:
* @udev_enumerate: udev enumeration context
*
* Scan /sys for all kernel subsystems, including buses, classes, drivers.
*
* Returns: 0 on success, otherwise a negative error value.
**/
_public_ int udev_enumerate_scan_subsystems(struct udev_enumerate *udev_enumerate)
{
struct stat statbuf;
const char *subsysdir;
if (udev_enumerate == NULL)
return -EINVAL;
/* all kernel modules */
if (match_subsystem(udev_enumerate, "module"))
scan_dir_and_add_devices(udev_enumerate, "module", NULL, NULL);
if (stat("/sys/subsystem", &statbuf) == 0)
subsysdir = "subsystem";
else
subsysdir = "bus";
/* all subsystems (only buses support coldplug) */
if (match_subsystem(udev_enumerate, "subsystem"))
scan_dir_and_add_devices(udev_enumerate, subsysdir, NULL, NULL);
/* all subsystem drivers */
if (match_subsystem(udev_enumerate, "drivers"))
scan_dir(udev_enumerate, subsysdir, "drivers", "drivers");
return 0;
}