udev-node.c revision 6c29f2b942358d4dd9d3e7c65c13c3612dded3cc
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski/*
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski * Copyright (C) 2003-2009 Kay Sievers <kay.sievers@vrfy.org>
4b90c3b8ee582daeead21ce272f11c952ef1631eTill Mossakowski *
cc9279b89cc62b80199696ac7e87b6d2bdd08e7aTill Mossakowski * This program is free software: you can redistribute it and/or modify
5f40e8aa2c372040ab519c6401627d64812922ffKlaus Luettich * it under the terms of the GNU General Public License as published by
c1015e823b467ffb3e58fe3eacb0db58937063baTill Mossakowski * the Free Software Foundation, either version 2 of the License, or
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich * (at your option) any later version.
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich *
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich * This program is distributed in the hope that it will be useful,
aa6f6fa09091e92016598584162b9ba909af48ccTill Mossakowski * but WITHOUT ANY WARRANTY; without even the implied warranty of
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich * GNU General Public License for more details.
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich *
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich * You should have received a copy of the GNU General Public License
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich * along with this program. If not, see <http://www.gnu.org/licenses/>.
ed6873e3c28f11208f6873e04a65c3c3aa012ed9Klaus Luettich */
e0eee2b8144337bb54feb78d5a8b043041c9e028Till Mossakowski
e0eee2b8144337bb54feb78d5a8b043041c9e028Till Mossakowski#include <stdlib.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <string.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <stdio.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <stddef.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <stdbool.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <fcntl.h>
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include <unistd.h>
b172714c339053a40393dc0cf4f9151c97695e01Till Mossakowski#include <errno.h>
b172714c339053a40393dc0cf4f9151c97695e01Till Mossakowski#include <grp.h>
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski#include <dirent.h>
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski#include <sys/stat.h>
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich#include <sys/types.h>
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich
89ee5859757b78fefccda0a582cc896bd422d006Klaus Luettich#include "udev.h"
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski#define TMP_FILE_EXT ".udev-tmp"
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowskiint udev_node_mknod(struct udev_device *dev, const char *file, dev_t devnum, mode_t mode, uid_t uid, gid_t gid)
baac12e7dd41b6e250e753c88ee0d40505509104Klaus Luettich{
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski struct udev *udev = udev_device_get_udev(dev);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski struct stat stats;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski int preserve = 0;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski int err = 0;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (major(devnum) == 0)
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski devnum = udev_device_get_devnum(dev);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski mode |= S_IFBLK;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski else
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski mode |= S_IFCHR;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (file == NULL)
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski file = udev_device_get_devnode(dev);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (lstat(file, &stats) == 0) {
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devnum)) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski info(udev, "preserve file '%s', because it has correct dev_t\n", file);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski preserve = 1;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski udev_selinux_lsetfilecon(udev, file, mode);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski } else {
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski info(udev, "atomically replace existing file '%s'\n", file);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski util_strscpyl(file_tmp, sizeof(file_tmp), file, TMP_FILE_EXT, NULL);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski unlink(file_tmp);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski udev_selinux_setfscreatecon(udev, file_tmp, mode);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski err = mknod(file_tmp, mode, devnum);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski udev_selinux_resetfscreatecon(udev);
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski if (err != 0) {
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski err(udev, "mknod(%s, %#o, %u, %u) failed: %m\n",
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski file_tmp, mode, major(devnum), minor(devnum));
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski goto exit;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err = rename(file_tmp, file);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (err != 0) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err(udev, "rename(%s, %s) failed: %m\n", file_tmp, file);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski unlink(file_tmp);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski } else {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski info(udev, "mknod(%s, %#o, (%u,%u))\n", file, mode, major(devnum), minor(devnum));
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski udev_selinux_setfscreatecon(udev, file, mode);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err = mknod(file, mode, devnum);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski udev_selinux_resetfscreatecon(udev);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (err != 0) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err(udev, "mknod(%s, %#o, (%u,%u) failed: %m\n", file, mode, major(devnum), minor(devnum));
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski goto exit;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (!preserve || stats.st_mode != mode) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski info(udev, "chmod(%s, %#o)\n", file, mode);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err = chmod(file, mode);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (err != 0) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err(udev, "chmod(%s, %#o) failed: %m\n", file, mode);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski goto exit;
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski }
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (!preserve || stats.st_uid != uid || stats.st_gid != gid) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski info(udev, "chown(%s, %u, %u)\n", file, uid, gid);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err = chown(file, uid, gid);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski if (err != 0) {
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski err(udev, "chown(%s, %u, %u) failed: %m\n", file, uid, gid);
7c610eb832a4575b209fc6e6c674b99975135012Till Mossakowski goto exit;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski }
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski }
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowskiexit:
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski return err;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski}
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowskistatic int node_symlink(struct udev *udev, const char *node, const char *slink)
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski{
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski struct stat stats;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski char target[UTIL_PATH_SIZE];
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski char *s;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski size_t l;
183e25edd6aaf48da3cfcf6e5a5300bed5a941dfTill Mossakowski char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
int i = 0;
int tail = 0;
int err = 0;
/* use relative link */
target[0] = '\0';
while (node[i] && (node[i] == slink[i])) {
if (node[i] == '/')
tail = i+1;
i++;
}
s = target;
l = sizeof(target);
while (slink[i] != '\0') {
if (slink[i] == '/')
l = util_strpcpy(&s, l, "../");
i++;
}
l = util_strscpy(s, l, &node[tail]);
if (l == 0) {
err = -EINVAL;
goto exit;
}
/* preserve link with correct target, do not replace node of other device */
if (lstat(slink, &stats) == 0) {
if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
struct stat stats2;
info(udev, "found existing node instead of symlink '%s'\n", slink);
if (lstat(node, &stats2) == 0) {
if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
info(udev, "replace device node '%s' with symlink to our node '%s'\n",
slink, node);
} else {
err(udev, "device node '%s' already exists, "
"link to '%s' will not overwrite it\n",
slink, node);
goto exit;
}
}
} else if (S_ISLNK(stats.st_mode)) {
char buf[UTIL_PATH_SIZE];
int len;
dbg(udev, "found existing symlink '%s'\n", slink);
len = readlink(slink, buf, sizeof(buf));
if (len > 0) {
buf[len] = '\0';
if (strcmp(target, buf) == 0) {
info(udev, "preserve already existing symlink '%s' to '%s'\n",
slink, target);
udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
goto exit;
}
}
}
} else {
info(udev, "creating symlink '%s' to '%s'\n", slink, target);
udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
err = symlink(target, slink);
udev_selinux_resetfscreatecon(udev);
if (err == 0)
goto exit;
}
info(udev, "atomically replace '%s'\n", slink);
util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
unlink(slink_tmp);
udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
err = symlink(target, slink_tmp);
udev_selinux_resetfscreatecon(udev);
if (err != 0) {
err(udev, "symlink(%s, %s) failed: %m\n", target, slink_tmp);
goto exit;
}
err = rename(slink_tmp, slink);
if (err != 0) {
err(udev, "rename(%s, %s) failed: %m\n", slink_tmp, slink);
unlink(slink_tmp);
}
exit:
return err;
}
/* find device node of device with highest priority */
static const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
{
struct udev *udev = udev_device_get_udev(dev);
DIR *dir;
int priority = 0;
const char *target = NULL;
if (add) {
priority = udev_device_get_devlink_priority(dev);
util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
target = buf;
}
dir = opendir(stackdir);
if (dir == NULL)
return target;
for (;;) {
struct udev_device *dev_db;
struct dirent *dent;
char devpath[UTIL_PATH_SIZE];
char syspath[UTIL_PATH_SIZE];
ssize_t len;
dent = readdir(dir);
if (dent == NULL || dent->d_name[0] == '\0')
break;
if (dent->d_name[0] == '.')
continue;
dbg(udev, "found '%s/%s'\n", stackdir, dent->d_name);
len = readlinkat(dirfd(dir), dent->d_name, devpath, sizeof(devpath));
if (len <= 0 || len == (ssize_t)sizeof(devpath))
continue;
devpath[len] = '\0';
util_strscpyl(syspath, sizeof(syspath), udev_get_sys_path(udev), devpath, NULL);
info(udev, "found '%s' claiming '%s'\n", syspath, stackdir);
/* did we find ourself? */
if (strcmp(udev_device_get_syspath(dev), syspath) == 0)
continue;
dev_db = udev_device_new_from_syspath(udev, syspath);
if (dev_db != NULL) {
const char *devnode;
devnode = udev_device_get_devnode(dev_db);
if (devnode != NULL) {
dbg(udev, "compare priority of '%s'(%i) > '%s'(%i)\n", target, priority,
udev_device_get_devnode(dev_db), udev_device_get_devlink_priority(dev_db));
if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
info(udev, "'%s' claims priority %i for '%s'\n",
syspath, udev_device_get_devlink_priority(dev_db), stackdir);
priority = udev_device_get_devlink_priority(dev_db);
util_strscpy(buf, bufsize, devnode);
target = buf;
}
}
udev_device_unref(dev_db);
}
}
return target;
}
/* manage "stack of names" with possibly specified device priorities */
static void link_update(struct udev_device *dev, const char *slink, bool add)
{
struct udev *udev = udev_device_get_udev(dev);
char name_enc[UTIL_PATH_SIZE];
char filename[UTIL_PATH_SIZE * 2];
char dirname[UTIL_PATH_SIZE];
const char *target;
char buf[UTIL_PATH_SIZE];
dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
snprintf(dirname, sizeof(dirname), "%s/.udev/links/%s", udev_get_dev_path(udev), name_enc);
snprintf(filename, sizeof(filename), "%s/%c%u:%u", dirname,
strcmp(udev_device_get_subsystem(dev), "block") == 0 ? 'b' : 'c',
major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
if (!add) {
dbg(udev, "removing index: '%s'\n", filename);
unlink(filename);
util_delete_path(udev, filename);
}
target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
if (target == NULL) {
info(udev, "no reference left, remove '%s'\n", slink);
unlink(slink);
util_delete_path(udev, slink);
} else {
util_create_path(udev, slink);
info(udev, "creating link '%s' to '%s'\n", slink, target);
node_symlink(udev, target, slink);
}
if (add) {
dbg(udev, "creating index: '%s'\n", filename);
util_create_path(udev, filename);
symlink(udev_device_get_devpath(dev), filename);
}
}
void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old)
{
struct udev *udev = udev_device_get_udev(dev);
struct udev_list_entry *list_entry;
/* update possible left-over symlinks */
udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev_old)) {
const char *name = udev_list_entry_get_name(list_entry);
struct udev_list_entry *list_entry_current;
int found;
/* check if old link name still belongs to this device */
found = 0;
udev_list_entry_foreach(list_entry_current, udev_device_get_devlinks_list_entry(dev)) {
const char *name_current = udev_list_entry_get_name(list_entry_current);
if (strcmp(name, name_current) == 0) {
found = 1;
break;
}
}
if (found)
continue;
info(udev, "update old name, '%s' no longer belonging to '%s'\n",
name, udev_device_get_devpath(dev));
link_update(dev, name, 0);
}
}
int udev_node_add(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
{
struct udev *udev = udev_device_get_udev(dev);
int i;
int num;
struct udev_list_entry *list_entry;
int err = 0;
info(udev, "creating device node '%s', devnum=%d:%d, mode=%#o, uid=%d, gid=%d\n",
udev_device_get_devnode(dev),
major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)),
mode, uid, gid);
util_create_path(udev, udev_device_get_devnode(dev));
if (udev_node_mknod(dev, NULL, makedev(0,0), mode, uid, gid) != 0) {
err = -1;
goto exit;
}
/* create all_partitions if requested */
num = udev_device_get_num_fake_partitions(dev);
if (num > 0) {
info(udev, "creating device partition nodes '%s[1-%i]'\n", udev_device_get_devnode(dev), num);
for (i = 1; i <= num; i++) {
char partitionname[UTIL_PATH_SIZE];
dev_t part_devnum;
snprintf(partitionname, sizeof(partitionname), "%s%d",
udev_device_get_devnode(dev), i);
partitionname[sizeof(partitionname)-1] = '\0';
part_devnum = makedev(major(udev_device_get_devnum(dev)),
minor(udev_device_get_devnum(dev)) + i);
udev_node_mknod(dev, partitionname, part_devnum, mode, uid, gid);
}
}
/* create/update symlinks, add symlinks to name index */
udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev)) {
if (udev_list_entry_get_flag(list_entry)) {
/* simple unmanaged link name */
util_create_path(udev, udev_list_entry_get_name(list_entry));
node_symlink(udev, udev_device_get_devnode(dev), udev_list_entry_get_name(list_entry));
} else {
link_update(dev, udev_list_entry_get_name(list_entry), 1);
}
}
exit:
return err;
}
int udev_node_remove(struct udev_device *dev)
{
struct udev *udev = udev_device_get_udev(dev);
struct udev_list_entry *list_entry;
const char *devnode;
char partitionname[UTIL_PATH_SIZE];
struct stat stats;
int err = 0;
int num;
/* remove,update symlinks, remove symlinks from name index */
udev_list_entry_foreach(list_entry, udev_device_get_devlinks_list_entry(dev))
link_update(dev, udev_list_entry_get_name(list_entry), 0);
devnode = udev_device_get_devnode(dev);
if (devnode == NULL)
return 0;
if (stat(devnode, &stats) != 0) {
info(udev, "device node '%s' not found\n", devnode);
return 0;
}
if (stats.st_rdev != udev_device_get_devnum(dev)) {
info(udev, "device node '%s' points to a different device, skip removal\n", devnode);
return -1;
}
info(udev, "removing device node '%s'\n", devnode);
err = util_unlink_secure(udev, devnode);
if (err)
return err;
num = udev_device_get_num_fake_partitions(dev);
if (num > 0) {
int i;
info(udev, "removing all_partitions '%s[1-%i]'\n", devnode, num);
if (num > 255)
return -1;
for (i = 1; i <= num; i++) {
snprintf(partitionname, sizeof(partitionname), "%s%d", devnode, i);
partitionname[sizeof(partitionname)-1] = '\0';
util_unlink_secure(udev, partitionname);
}
}
util_delete_path(udev, devnode);
return err;
}