systemd/src/udev-node.c

	udev-node.c revision e7f32890335886cfa0f2f835413aed5af8ac2b53
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski/*
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * Copyright (C) 2003-2010 Kay Sievers <kay.sievers@vrfy.org>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski *
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * This program is free software: you can redistribute it and/or modify
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * it under the terms of the GNU General Public License as published by
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * the Free Software Foundation, either version 2 of the License, or
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * (at your option) any later version.
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski *
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * This program is distributed in the hope that it will be useful,
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * but WITHOUT ANY WARRANTY; without even the implied warranty of
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * GNU General Public License for more details.
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski *
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * You should have received a copy of the GNU General Public License
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski * along with this program.  If not, see <http://www.gnu.org/licenses/>.
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski */
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <stdlib.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <string.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <stdio.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <stddef.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <stdbool.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <fcntl.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <unistd.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <errno.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <grp.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <dirent.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <sys/time.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <sys/stat.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include <sys/types.h>
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#include "udev.h"
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski#define TMP_FILE_EXT                ".udev-tmp"
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowskistatic int node_symlink(struct udev *udev, const char *node, const char *slink)
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski{
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        struct stat stats;
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        char target[UTIL_PATH_SIZE];
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        char *s;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        size_t l;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        char slink_tmp[UTIL_PATH_SIZE + sizeof(TMP_FILE_EXT)];
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        int i = 0;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        int tail = 0;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        int err = 0;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        /* use relative link */
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        target[0] = '\0';
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        while (node[i] && (node[i] == slink[i])) {
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                if (node[i] == '/')
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                        tail = i+1;
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                i++;
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        }
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        s = target;
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        l = sizeof(target);
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski        while (slink[i] != '\0') {
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                if (slink[i] == '/')
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                        l = util_strpcpy(&s, l, "../");
db373255bd95ce4de47dde876c3a3bfc49c22a97Till Mossakowski                i++;
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        }
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        l = util_strscpy(s, l, &node[tail]);
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski        if (l == 0) {
1c1b291a3d146eeb4e7e66e73e9fa891e075b509Till Mossakowski                err = -EINVAL;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                goto exit;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        /* preserve link with correct target, do not replace node of other device */
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski        if (lstat(slink, &stats) == 0) {
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski                if (S_ISBLK(stats.st_mode) || S_ISCHR(stats.st_mode)) {
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski                        struct stat stats2;
f69658e57cba7ecb37c0d84181f4c563215c2534Till Mossakowski
f69658e57cba7ecb37c0d84181f4c563215c2534Till Mossakowski                        info(udev, "found existing node instead of symlink '%s'\n", slink);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        if (lstat(node, &stats2) == 0) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                if ((stats.st_mode & S_IFMT) == (stats2.st_mode & S_IFMT) &&
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                    stats.st_rdev == stats2.st_rdev && stats.st_ino != stats2.st_ino) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        info(udev, "replace device node '%s' with symlink to our node '%s'\n",
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                             slink, node);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                } else {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        err(udev, "device node '%s' already exists, "
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                            "link to '%s' will not overwrite it\n",
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                            slink, node);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        goto exit;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                } else if (S_ISLNK(stats.st_mode)) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        char buf[UTIL_PATH_SIZE];
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        int len;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        dbg(udev, "found existing symlink '%s'\n", slink);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        len = readlink(slink, buf, sizeof(buf));
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        if (len > 0 && len < (int)sizeof(buf)) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                buf[len] = '\0';
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                if (strcmp(target, buf) == 0) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        info(udev, "preserve already existing symlink '%s' to '%s'\n",
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                             slink, target);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        udev_selinux_lsetfilecon(udev, slink, S_IFLNK);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        utimensat(AT_FDCWD, slink, NULL, AT_SYMLINK_NOFOLLOW);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        goto exit;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        } else {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                info(udev, "creating symlink '%s' to '%s'\n", slink, target);
67d5e49547d78aa56a8f9ba5e64a950b730eba66Till Mossakowski                do {
67d5e49547d78aa56a8f9ba5e64a950b730eba66Till Mossakowski                        err = util_create_path_selinux(udev, slink);
67d5e49547d78aa56a8f9ba5e64a950b730eba66Till Mossakowski                        if (err != 0 && err != -ENOENT)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                break;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        udev_selinux_setfscreatecon(udev, slink, S_IFLNK);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        err = symlink(target, slink);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        if (err != 0)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                err = -errno;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        udev_selinux_resetfscreatecon(udev);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                } while (err == -ENOENT);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (err == 0)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        goto exit;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski        info(udev, "atomically replace '%s'\n", slink);
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski        util_strscpyl(slink_tmp, sizeof(slink_tmp), slink, TMP_FILE_EXT, NULL);
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski        unlink(slink_tmp);
83a9571a3df107123eb25f59ac52c576468f2952Till Mossakowski        do {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                err = util_create_path_selinux(udev, slink_tmp);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (err != 0 && err != -ENOENT)
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                        break;
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                udev_selinux_setfscreatecon(udev, slink_tmp, S_IFLNK);
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                err = symlink(target, slink_tmp);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (err != 0)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        err = -errno;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                udev_selinux_resetfscreatecon(udev);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        } while (err == -ENOENT);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        if (err != 0) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                err(udev, "symlink '%s' '%s' failed: %m\n", target, slink_tmp);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                goto exit;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        err = rename(slink_tmp, slink);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        if (err != 0) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                err(udev, "rename '%s' '%s' failed: %m\n", slink_tmp, slink);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                unlink(slink_tmp);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowskiexit:
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        return err;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski}
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski/* find device node of device with highest priority */
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowskistatic const char *link_find_prioritized(struct udev_device *dev, bool add, const char *stackdir, char *buf, size_t bufsize)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski{
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        struct udev *udev = udev_device_get_udev(dev);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        DIR *dir;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        int priority = 0;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        const char *target = NULL;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        if (add) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                priority = udev_device_get_devlink_priority(dev);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                util_strscpy(buf, bufsize, udev_device_get_devnode(dev));
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                target = buf;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        dir = opendir(stackdir);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        if (dir == NULL)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                return target;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        for (;;) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                struct udev_device *dev_db;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                struct dirent *dent;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                dent = readdir(dir);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (dent == NULL || dent->d_name[0] == '\0')
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        break;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (dent->d_name[0] == '.')
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        continue;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                info(udev, "found '%s' claiming '%s'\n", dent->d_name, stackdir);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                /* did we find ourself? */
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (strcmp(dent->d_name, udev_device_get_id_filename(dev)) == 0)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        continue;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                dev_db = udev_device_new_from_id_filename(udev, dent->d_name);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                if (dev_db != NULL) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        const char *devnode;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        devnode = udev_device_get_devnode(dev_db);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        if (devnode != NULL) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                dbg(udev, "compare priority of '%s'(%i) > '%s'(%i)\n", target, priority,
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                    udev_device_get_devnode(dev_db), udev_device_get_devlink_priority(dev_db));
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                if (target == NULL || udev_device_get_devlink_priority(dev_db) > priority) {
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        info(udev, "'%s' claims priority %i for '%s'\n",
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                             udev_device_get_syspath(dev_db), udev_device_get_devlink_priority(dev_db), stackdir);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        priority = udev_device_get_devlink_priority(dev_db);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        util_strscpy(buf, bufsize, devnode);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                        target = buf;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                                }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                        udev_device_unref(dev_db);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski                }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        }
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        closedir(dir);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        return target;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski}
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski/* manage "stack of names" with possibly specified device priorities */
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowskistatic void link_update(struct udev_device *dev, const char *slink, bool add)
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski{
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        struct udev *udev = udev_device_get_udev(dev);
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        char name_enc[UTIL_PATH_SIZE];
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        char filename[UTIL_PATH_SIZE * 2];
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        char dirname[UTIL_PATH_SIZE];
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        const char *target;
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        char buf[UTIL_PATH_SIZE];
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski        dbg(udev, "update symlink '%s' of '%s'\n", slink, udev_device_get_syspath(dev));
144d4893ba5a3815bd1639d498ee4a20ed13a211Till Mossakowski
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        util_path_encode(&slink[strlen(udev_get_dev_path(udev))+1], name_enc, sizeof(name_enc));
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        util_strscpyl(dirname, sizeof(dirname), udev_get_run_path(udev), "/links/", name_enc, NULL);
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        util_strscpyl(filename, sizeof(filename), dirname, "/", udev_device_get_id_filename(dev), NULL);
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        if (!add) {
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                dbg(udev, "removing index: '%s'\n", filename);
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                if (unlink(filename) == 0)
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski                        rmdir(dirname);
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        }
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski
968edf72c9abb1e35ad5f41419d0399c6d9acf32Till Mossakowski        target = link_find_prioritized(dev, add, dirname, buf, sizeof(buf));
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski        if (target == NULL) {
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski                info(udev, "no reference left, remove '%s'\n", slink);
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski                if (unlink(slink) == 0)
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski                        util_delete_path(udev, slink);
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski        } else {
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski                info(udev, "creating link '%s' to '%s'\n", slink, target);
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski                node_symlink(udev, target, slink);
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski        }
f3a84cc409ed345569be6673d05072dcb4291ebeTill Mossakowski
        if (add) {
                int err;

                dbg(udev, "creating index: '%s'\n", filename);
                do {
                        int fd;

                        err = util_create_path(udev, filename);
                        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 *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);
        }
}

static int node_fixup(struct udev_device *dev, mode_t mode, uid_t uid, gid_t gid)
{
        struct udev *udev = udev_device_get_udev(dev);
        const char *devnode = udev_device_get_devnode(dev);
        dev_t devnum = udev_device_get_devnum(dev);
        struct stat stats;
        int err = 0;

        if (strcmp(udev_device_get_subsystem(dev), "block") == 0)
                mode |= S_IFBLK;
        else
                mode |= S_IFCHR;

        if (lstat(devnode, &stats) != 0) {
                err = -errno;
                info(udev, "can not stat() node '%s' (%m)\n", devnode);
                goto out;
        }

        if (((stats.st_mode & S_IFMT) != (mode & S_IFMT)) || (stats.st_rdev != devnum)) {
                err = -EEXIST;
                info(udev, "found node '%s' with non-matching devnum %s, skip handling\n",
                     udev_device_get_devnode(dev), udev_device_get_id_filename(dev));
                goto out;
        }

        if ((stats.st_mode & 0777) != (mode & 0777) || stats.st_uid != uid || stats.st_gid != gid) {
                info(udev, "set permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
                chmod(devnode, mode);
                chown(devnode, uid, gid);
        } else {
                info(udev, "preserve permissions %s, %#o, uid=%u, gid=%u\n", devnode, mode, uid, gid);
        }

        /*
         * Set initial selinux file context only on add events.
         * We set the proper context on bootup (triger) or for newly
         * added devices, but we don't change it later, in case
         * something else has set a custom context in the meantime.
         */
        if (strcmp(udev_device_get_action(dev), "add") == 0)
                udev_selinux_lsetfilecon(udev, devnode, mode);

        /* 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, mode_t mode, uid_t uid, gid_t gid)
{
        struct udev *udev = udev_device_get_udev(dev);
        char filename[UTIL_PATH_SIZE];
        struct udev_list_entry *list_entry;
        int err = 0;

        info(udev, "handling device node '%s', devnum=%s, mode=%#o, uid=%d, gid=%d\n",
             udev_device_get_devnode(dev), udev_device_get_id_filename(dev), mode, uid, gid);

        if (node_fixup(dev, mode, uid, gid) < 0)
                return;

        /* always add /dev/{block,char}/$major:$minor */
        snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
                 udev_get_dev_path(udev),
                 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
                 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
        node_symlink(udev, 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)) {
                if (udev_list_entry_get_num(list_entry))
                        /* simple unmanaged link name */
                        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);
        }
}

void udev_node_remove(struct udev_device *dev)
{
        struct udev *udev = udev_device_get_udev(dev);
        struct udev_list_entry *list_entry;
        const char *devnode;
        struct stat stats;
        struct udev_device *dev_check;
        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), 0);

        /* remove /dev/{block,char}/$major:$minor */
        snprintf(filename, sizeof(filename), "%s/%s/%u:%u",
                 udev_get_dev_path(udev),
                 strcmp(udev_device_get_subsystem(dev), "block") == 0 ? "block" : "char",
                 major(udev_device_get_devnum(dev)), minor(udev_device_get_devnum(dev)));
        unlink(filename);
}