udev_node.c revision 17fcfb5972977b6a3aedca6ad2aa8d1fbfbc761d
/*
* Copyright (C) 2004-2008 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 <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <stddef.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <grp.h>
#include <dirent.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "udev.h"
#include "udev_rules.h"
#define TMP_FILE_EXT ".udev-tmp"
int udev_node_mknod(struct udevice *udevice, const char *file, dev_t devt, mode_t mode, uid_t uid, gid_t gid)
{
char file_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
struct stat stats;
int preserve = 0;
int err = 0;
if (major(devt) != 0 && strcmp(udevice->dev->subsystem, "block") == 0)
mode |= S_IFBLK;
else
mode |= S_IFCHR;
if (lstat(file, &stats) == 0) {
if (((stats.st_mode & S_IFMT) == (mode & S_IFMT)) && (stats.st_rdev == devt)) {
info(udevice->udev, "preserve file '%s', because it has correct dev_t\n", file);
preserve = 1;
udev_selinux_lsetfilecon(udevice->udev, file, mode);
} else {
info(udevice->udev, "atomically replace existing file '%s'\n", file);
util_strlcpy(file_tmp, file, sizeof(file_tmp));
util_strlcat(file_tmp, TMP_FILE_EXT, sizeof(file_tmp));
unlink(file_tmp);
udev_selinux_setfscreatecon(udevice->udev, file_tmp, mode);
err = mknod(file_tmp, mode, devt);
udev_selinux_resetfscreatecon(udevice->udev);
if (err != 0) {
err(udevice->udev, "mknod(%s, %#o, %u, %u) failed: %s\n",
file_tmp, mode, major(devt), minor(devt), strerror(errno));
goto exit;
}
err = rename(file_tmp, file);
if (err != 0) {
err(udevice->udev, "rename(%s, %s) failed: %s\n", file_tmp, file, strerror(errno));
unlink(file_tmp);
}
}
} else {
info(udevice->udev, "mknod(%s, %#o, (%u,%u))\n", file, mode, major(devt), minor(devt));
udev_selinux_setfscreatecon(udevice->udev, file, mode);
err = mknod(file, mode, devt);
udev_selinux_resetfscreatecon(udevice->udev);
if (err != 0) {
err(udevice->udev, "mknod(%s, %#o, (%u,%u) failed: %s\n",
file, mode, major(devt), minor(devt), strerror(errno));
goto exit;
}
}
if (!preserve || stats.st_mode != mode) {
info(udevice->udev, "chmod(%s, %#o)\n", file, mode);
err = chmod(file, mode);
if (err != 0) {
err(udevice->udev, "chmod(%s, %#o) failed: %s\n", file, mode, strerror(errno));
goto exit;
}
}
if (!preserve || stats.st_uid != uid || stats.st_gid != gid) {
info(udevice->udev, "chown(%s, %u, %u)\n", file, uid, gid);
err = chown(file, uid, gid);
if (err != 0) {
err(udevice->udev, "chown(%s, %u, %u) failed: %s\n", file, uid, gid, strerror(errno));
goto exit;
}
}
exit:
return err;
}
static int node_symlink(struct udevice *udevice, const char *node, const char *slink)
{
struct stat stats;
char target[UTIL_PATH_SIZE] = "";
char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
int i = 0;
int tail = 0;
int len;
int retval = 0;
/* use relative link */
while (node[i] && (node[i] == slink[i])) {
if (node[i] == '/')
tail = i+1;
i++;
}
while (slink[i] != '\0') {
if (slink[i] == '/')
util_strlcat(target, "../", sizeof(target));
i++;
}
util_strlcat(target, &node[tail], sizeof(target));
/* 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(udevice->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) {
info(udevice->udev, "replace device node '%s' with symlink to our node '%s'\n", slink, node);
} else {
err(udevice->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];
info(udevice->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(udevice->udev, "preserve already existing symlink '%s' to '%s'\n", slink, target);
udev_selinux_lsetfilecon(udevice->udev, slink, S_IFLNK);
goto exit;
}
}
}
} else {
info(udevice->udev, "creating symlink '%s' to '%s'\n", slink, target);
udev_selinux_setfscreatecon(udevice->udev, slink, S_IFLNK);
retval = symlink(target, slink);
udev_selinux_resetfscreatecon(udevice->udev);
if (retval == 0)
goto exit;
}
info(udevice->udev, "atomically replace '%s'\n", slink);
util_strlcpy(slink_tmp, slink, sizeof(slink_tmp));
util_strlcat(slink_tmp, TMP_FILE_EXT, sizeof(slink_tmp));
unlink(slink_tmp);
udev_selinux_setfscreatecon(udevice->udev, slink, S_IFLNK);
retval = symlink(target, slink_tmp);
udev_selinux_resetfscreatecon(udevice->udev);
if (retval != 0) {
err(udevice->udev, "symlink(%s, %s) failed: %s\n", target, slink_tmp, strerror(errno));
goto exit;
}
retval = rename(slink_tmp, slink);
if (retval != 0) {
err(udevice->udev, "rename(%s, %s) failed: %s\n", slink_tmp, slink, strerror(errno));
unlink(slink_tmp);
goto exit;
}
exit:
return retval;
}
static int update_link(struct udevice *udevice, const char *name)
{
LIST_HEAD(name_list);
char slink[UTIL_PATH_SIZE];
char node[UTIL_PATH_SIZE];
struct udevice *udevice_db;
struct name_entry *device;
char target[UTIL_PATH_SIZE] = "";
int count;
int priority = 0;
int rc = 0;
util_strlcpy(slink, udev_get_dev_path(udevice->udev), sizeof(slink));
util_strlcat(slink, "/", sizeof(slink));
util_strlcat(slink, name, sizeof(slink));
count = udev_db_get_devices_by_name(udevice->udev, name, &name_list);
info(udevice->udev, "found %i devices with name '%s'\n", count, name);
/* if we don't have a reference, delete it */
if (count <= 0) {
info(udevice->udev, "no reference left, remove '%s'\n", name);
if (!udevice->test_run) {
unlink(slink);
delete_path(udevice->udev, slink);
}
goto out;
}
/* find the device with the highest priority */
list_for_each_entry(device, &name_list, node) {
info(udevice->udev, "found '%s' for '%s'\n", device->name, name);
/* did we find ourself? we win, if we have the same priority */
if (strcmp(udevice->dev->devpath, device->name) == 0) {
info(udevice->udev, "compare (our own) priority of '%s' %i >= %i\n",
udevice->dev->devpath, udevice->link_priority, priority);
if (strcmp(udevice->name, name) == 0) {
info(udevice->udev, "'%s' is our device node, database inconsistent, skip link update\n", udevice->name);
} else if (target[0] == '\0' || udevice->link_priority >= priority) {
priority = udevice->link_priority;
util_strlcpy(target, udevice->name, sizeof(target));
}
continue;
}
/* another device, read priority from database */
udevice_db = udev_device_init(udevice->udev);
if (udevice_db == NULL)
continue;
if (udev_db_get_device(udevice_db, device->name) == 0) {
if (strcmp(udevice_db->name, name) == 0) {
info(udevice->udev, "'%s' is a device node of '%s', skip link update\n", udevice_db->name, device->name);
} else {
info(udevice->udev, "compare priority of '%s' %i > %i\n",
udevice_db->dev->devpath, udevice_db->link_priority, priority);
if (target[0] == '\0' || udevice_db->link_priority > priority) {
priority = udevice_db->link_priority;
util_strlcpy(target, udevice_db->name, sizeof(target));
}
}
}
udev_device_cleanup(udevice_db);
}
name_list_cleanup(udevice->udev, &name_list);
if (target[0] == '\0') {
info(udevice->udev, "no current target for '%s' found\n", name);
rc = 1;
goto out;
}
/* create symlink to the target with the highest priority */
util_strlcpy(node, udev_get_dev_path(udevice->udev), sizeof(node));
util_strlcat(node, "/", sizeof(node));
util_strlcat(node, target, sizeof(node));
info(udevice->udev, "'%s' with target '%s' has the highest priority %i, create it\n", name, target, priority);
if (!udevice->test_run) {
create_path(udevice->udev, slink);
node_symlink(udevice, node, slink);
}
out:
return rc;
}
void udev_node_update_symlinks(struct udevice *udevice, struct udevice *udevice_old)
{
struct name_entry *name_loop;
char symlinks[UTIL_PATH_SIZE] = "";
list_for_each_entry(name_loop, &udevice->symlink_list, node) {
info(udevice->udev, "update symlink '%s' of '%s'\n", name_loop->name, udevice->dev->devpath);
update_link(udevice, name_loop->name);
util_strlcat(symlinks, udev_get_dev_path(udevice->udev), sizeof(symlinks));
util_strlcat(symlinks, "/", sizeof(symlinks));
util_strlcat(symlinks, name_loop->name, sizeof(symlinks));
util_strlcat(symlinks, " ", sizeof(symlinks));
}
/* export symlinks to environment */
util_remove_trailing_chars(symlinks, ' ');
if (symlinks[0] != '\0')
setenv("DEVLINKS", symlinks, 1);
/* update possible left-over symlinks (device metadata changed) */
if (udevice_old != NULL) {
struct name_entry *link_loop;
struct name_entry *link_old_loop;
int found;
/* remove current symlinks from old list */
list_for_each_entry(link_old_loop, &udevice_old->symlink_list, node) {
found = 0;
list_for_each_entry(link_loop, &udevice->symlink_list, node) {
if (strcmp(link_old_loop->name, link_loop->name) == 0) {
found = 1;
break;
}
}
if (!found) {
/* link does no longer belong to this device */
info(udevice->udev, "update old symlink '%s' no longer belonging to '%s'\n",
link_old_loop->name, udevice->dev->devpath);
update_link(udevice, link_old_loop->name);
}
}
/*
* if the node name has changed, delete the node,
* or possibly restore a symlink of another device
*/
if (strcmp(udevice->name, udevice_old->name) != 0)
update_link(udevice, udevice_old->name);
}
}
int udev_node_add(struct udevice *udevice)
{
char filename[UTIL_PATH_SIZE];
uid_t uid;
gid_t gid;
int i;
int retval = 0;
util_strlcpy(filename, udev_get_dev_path(udevice->udev), sizeof(filename));
util_strlcat(filename, "/", sizeof(filename));
util_strlcat(filename, udevice->name, sizeof(filename));
create_path(udevice->udev, filename);
if (strcmp(udevice->owner, "root") == 0)
uid = 0;
else {
char *endptr;
unsigned long id;
id = strtoul(udevice->owner, &endptr, 10);
if (endptr[0] == '\0')
uid = (uid_t) id;
else
uid = lookup_user(udevice->udev, udevice->owner);
}
if (strcmp(udevice->group, "root") == 0)
gid = 0;
else {
char *endptr;
unsigned long id;
id = strtoul(udevice->group, &endptr, 10);
if (endptr[0] == '\0')
gid = (gid_t) id;
else
gid = lookup_group(udevice->udev, udevice->group);
}
info(udevice->udev, "creating device node '%s', major=%d, minor=%d, mode=%#o, uid=%d, gid=%d\n",
filename, major(udevice->devt), minor(udevice->devt), udevice->mode, uid, gid);
if (!udevice->test_run)
if (udev_node_mknod(udevice, filename, udevice->devt, udevice->mode, uid, gid) != 0) {
retval = -1;
goto exit;
}
setenv("DEVNAME", filename, 1);
/* create all_partitions if requested */
if (udevice->partitions) {
char partitionname[UTIL_PATH_SIZE];
char *attr;
int range;
/* take the maximum registered minor range */
attr = sysfs_attr_get_value(udevice->udev, udevice->dev->devpath, "range");
if (attr != NULL) {
range = atoi(attr);
if (range > 1)
udevice->partitions = range-1;
}
info(udevice->udev, "creating device partition nodes '%s[1-%i]'\n", filename, udevice->partitions);
if (!udevice->test_run) {
for (i = 1; i <= udevice->partitions; i++) {
dev_t part_devt;
snprintf(partitionname, sizeof(partitionname), "%s%d", filename, i);
partitionname[sizeof(partitionname)-1] = '\0';
part_devt = makedev(major(udevice->devt), minor(udevice->devt) + i);
udev_node_mknod(udevice, partitionname, part_devt, udevice->mode, uid, gid);
}
}
}
exit:
return retval;
}
int udev_node_remove(struct udevice *udevice)
{
char filename[UTIL_PATH_SIZE];
char partitionname[UTIL_PATH_SIZE];
struct stat stats;
int retval = 0;
int num;
util_strlcpy(filename, udev_get_dev_path(udevice->udev), sizeof(filename));
util_strlcat(filename, "/", sizeof(filename));
util_strlcat(filename, udevice->name, sizeof(filename));
if (stat(filename, &stats) != 0) {
info(udevice->udev, "device node '%s' not found\n", filename);
return 0;
}
if (udevice->devt && stats.st_rdev != udevice->devt) {
info(udevice->udev, "device node '%s' points to a different device, skip removal\n", filename);
return -1;
}
info(udevice->udev, "removing device node '%s'\n", filename);
if (!udevice->test_run)
retval = unlink_secure(udevice->udev, filename);
if (retval)
return retval;
setenv("DEVNAME", filename, 1);
num = udevice->partitions;
if (num > 0) {
int i;
info(udevice->udev, "removing all_partitions '%s[1-%i]'\n", filename, num);
if (num > 255)
return -1;
for (i = 1; i <= num; i++) {
snprintf(partitionname, sizeof(partitionname), "%s%d", filename, i);
partitionname[sizeof(partitionname)-1] = '\0';
if (!udevice->test_run)
unlink_secure(udevice->udev, partitionname);
}
}
delete_path(udevice->udev, filename);
return retval;
}