+++ /dev/null
-/*
- * Copyright (C) 2003-2013 Kay Sievers <kay@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 <string.h>
-#include <stdio.h>
-#include <stddef.h>
-#include <stdbool.h>
-#include <fcntl.h>
-#include <unistd.h>
-#include <errno.h>
-#include <dirent.h>
-#include <sys/stat.h>
-
-#include "udev.h"
-#include "smack-util.h"
-#include "selinux-util.h"
-
-static int node_symlink(struct udev_device *dev, const char *node, const char *slink) {
- struct stat stats;
- char target[UTIL_PATH_SIZE];
- char *s;
- size_t l;
- char slink_tmp[UTIL_PATH_SIZE + 32];
- 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 = strpcpy(&s, l, "../");
- i++;
- }
- l = 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)) {
- log_error("conflicting device node '%s' found, link to '%s' will not be created", slink, node);
- goto exit;
- } else if (S_ISLNK(stats.st_mode)) {
- char buf[UTIL_PATH_SIZE];
- int len;
-
- len = readlink(slink, buf, sizeof(buf));
- if (len > 0 && len < (int)sizeof(buf)) {
- buf[len] = '\0';
- if (streq(target, buf)) {
- log_debug("preserve already existing symlink '%s' to '%s'", slink, target);
- label_fix(slink, true, false);
- utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
- goto exit;
- }
- }
- }
- } else {
- log_debug("creating symlink '%s' to '%s'", slink, target);
- do {
- err = mkdir_parents_label(slink, 0755);
- if (err != 0 && err != -ENOENT)
- break;
- mac_selinux_create_file_prepare(slink, S_IFLNK);
- err = symlink(target, slink);
- if (err != 0)
- err = -errno;
- mac_selinux_create_file_clear();
- } while (err == -ENOENT);
- if (err == 0)
- goto exit;
- }
-
- log_debug("atomically replace '%s'", slink);
- strscpyl(slink_tmp, sizeof(slink_tmp), slink, ".tmp-", udev_device_get_id_filename(dev), NULL);
- unlink(slink_tmp);
- do {
- err = mkdir_parents_label(slink_tmp, 0755);
- if (err != 0 && err != -ENOENT)
- break;
- mac_selinux_create_file_prepare(slink_tmp, S_IFLNK);
- err = symlink(target, slink_tmp);
- if (err != 0)
- err = -errno;
- mac_selinux_create_file_clear();
- } while (err == -ENOENT);
- if (err != 0) {
- log_error_errno(errno, "symlink '%s' '%s' failed: %m", target, slink_tmp);
- goto exit;
- }
- err = rename(slink_tmp, slink);
- if (err != 0) {
- log_error_errno(errno, "rename '%s' '%s' failed: %m", 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);
- 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;
-
- dent = readdir(dir);
- if (dent == NULL || dent->d_name[0] == '\0')
- break;
- if (dent->d_name[0] == '.')
- continue;
-
- log_debug("found '%s' claiming '%s'", dent->d_name, stackdir);
-
- /* did we find ourself? */
- if (streq(dent->d_name, udev_device_get_id_filename(dev)))
- continue;
-
- dev_db = udev_device_new_from_device_id(udev, dent->d_name);
- if (dev_db != NULL) {
- const char *devnode;
-
- devnode = udev_device_get_devnode(dev_db);
- if (devnode != NULL) {
- if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
- log_debug("'%s' claims priority %i for '%s'",
- udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
- priority = udev_device_get_devlink_priority(dev_db);
- strscpy(buf, bufsize, devnode);
- target = buf;
- }
- }
- udev_device_unref(dev_db);
- }
- }
- closedir(dir);
- return target;
-}
-
-/* manage "stack of names" with possibly specified device priorities */
-static void link_update(struct udev_device *dev, const char *slink, bool add) {
- 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];
-
- util_path_encode(slink + strlen("/dev"), name_enc, sizeof(name_enc));
- strscpyl(dirname, sizeof(dirname), "/run/udev/links/", name_enc, NULL);
- strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
-
- if (!add && unlink(filename) == 0)
- rmdir(dirname);
-
- target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
- if (target == NULL) {
- log_debug("no reference left, remove '%s'", slink);
- if (unlink(slink) == 0)
- rmdir_parents(slink, "/");
- } else {
- log_debug("creating link '%s' to '%s'", slink, target);
- node_symlink(dev, target, slink);
- }
-
- if (add) {
- int err;
-
- do {
- int fd;
-
- err = mkdir_parents(filename, 0755);
- if (err != 0 && err != -ENOENT)
- break;
- fd = open(filename, O_WRONLY|O_CREAT|O_CLOEXEC|O_TRUNC|O_NOFOLLOW, 0444);
- if (fd >= 0)
- close(fd);
- else
- err = -errno;
- } while (err == -ENOENT);
- }
-}
-
-void udev_node_update_old_links(struct udev_device *dev, struct udev_device *dev_old) {
- 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 (streq(name, name_current)) {
- found = 1;
- break;
- }
- }
- if (found)
- continue;
-
- log_debug("update old name, '%s' no longer belonging to '%s'",
- name, udev_device_get_devpath(dev));
- link_update(dev, name, false);
- }
-}
-
-static int node_permissions_apply(struct udev_device *dev, bool apply,
- mode_t mode, uid_t uid, gid_t gid,
- struct udev_list *seclabel_list) {
- const char *devnode = udev_device_get_devnode(dev);
- dev_t devnum = udev_device_get_devnum(dev);
- struct stat stats;
- struct udev_list_entry *entry;
- int err = 0;
-
- if (streq(udev_device_get_subsystem(dev), "block"))
- mode |= S_IFBLK;
- else
- mode |= S_IFCHR;
-
- if (lstat(devnode, &stats) != 0) {
- err = -errno;
- log_debug_errno(errno, "can not stat() node '%s' (%m)", devnode);
- goto out;
- }
-
- if (((stats.st_mode & S_IFMT) != (mode & S_IFMT)) || (stats.st_rdev != devnum)) {
- err = -EEXIST;
- log_debug("found node '%s' with non-matching devnum %s, skip handling",
- udev_device_get_devnode(dev), udev_device_get_id_filename(dev));
- goto out;
- }
-
- if (apply) {
- bool selinux = false;
- bool smack = false;
-
- if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
- log_debug("set permissions %s, %#o, uid=%u, gid=%u", devnode, mode, uid, gid);
- err = chmod(devnode, mode);
- if (err < 0)
- log_warning_errno(errno, "setting mode of %s to %#o failed: %m", devnode, mode);
- err = chown(devnode, uid, gid);
- if (err < 0)
- log_warning_errno(errno, "setting owner of %s to uid=%u, gid=%u failed: %m", devnode, uid, gid);
- } else {
- log_debug("preserve permissions %s, %#o, uid=%u, gid=%u", devnode, mode, uid, gid);
- }
-
- /* apply SECLABEL{$module}=$label */
- udev_list_entry_foreach(entry, udev_list_get_entry(seclabel_list)) {
- const char *name, *label;
- int r;
-
- name = udev_list_entry_get_name(entry);
- label = udev_list_entry_get_value(entry);
-
- if (streq(name, "selinux")) {
- selinux = true;
-
- r = mac_selinux_apply(devnode, label);
- if (r < 0)
- log_error_errno(r, "SECLABEL: failed to set SELinux label '%s': %m", label);
- else
- log_debug("SECLABEL: set SELinux label '%s'", label);
-
- } else if (streq(name, "smack")) {
- smack = true;
-
- r = mac_smack_apply(devnode, label);
- if (r < 0)
- log_error_errno(r, "SECLABEL: failed to set SMACK label '%s': %m", label);
- else
- log_debug("SECLABEL: set SMACK label '%s'", label);
-
- } else
- log_error("SECLABEL: unknown subsystem, ignoring '%s'='%s'", name, label);
- }
-
- /* set the defaults */
- if (!selinux)
- mac_selinux_fix(devnode, true, false);
- if (!smack)
- mac_smack_apply(devnode, NULL);
- }
-
- /* always update timestamp when we re-use the node, like on media change events */
- utimensat(AT_FDCWD, devnode, NULL, 0);
-out:
- return err;
-}
-
-void udev_node_add(struct udev_device *dev, bool apply,
- mode_t mode, uid_t uid, gid_t gid,
- struct udev_list *seclabel_list) {
- char filename[UTIL_PATH_SIZE];
- struct udev_list_entry *list_entry;
-
- log_debug("handling device node '%s', devnum=%s, mode=%#o, uid="UID_FMT", gid="GID_FMT,
- udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid);
-
- if (node_permissions_apply(dev, apply, mode, uid, gid, seclabel_list) < 0)
- return;
-
- /* always add /dev/{block,char}/$major:$minor */
- snprintf(filename, sizeof(filename), "/dev/%s/%u:%u",
- streq(udev_device_get_subsystem(dev), "block") ? "block" : "char",
- major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
- node_symlink(dev, udev_device_get_devnode(dev), filename);
-
- /* create/update symlinks, add symlinks to 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), true);
-}
-
-void udev_node_remove(struct udev_device *dev) {
- struct udev_list_entry *list_entry;
- char filename[UTIL_PATH_SIZE];
-
- /* 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), false);
-
- /* remove /dev/{block,char}/$major:$minor */
- snprintf(filename, sizeof(filename), "/dev/%s/%u:%u",
- streq(udev_device_get_subsystem(dev), "block") ? "block" : "char",
- major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
- unlink(filename);
-}
~ianmdlvl / elogind.git / blobdiff