conf: make use of stashed container mountpoint fd in mount_autodev()

src/lxc/conf.c

@@ -1051,7 +1051,6 @@ on_error:
 static int mount_autodev(const char *name, const struct lxc_rootfs *rootfs,
 			 int autodevtmpfssize, const char *lxcpath)
 {
-	__do_close int root_mntpt_fd = -EBADF;
 	const char *path = rootfs->path ? rootfs->mount : NULL;
 	int ret;
 	mode_t cur_mask;
@@ -1062,19 +1061,15 @@ static int mount_autodev(const char *name, const struct lxc_rootfs *rootfs,
 	sprintf(mount_options, "size=%d,mode=755", (autodevtmpfssize != 0) ? autodevtmpfssize : 500000);
 	DEBUG("Using mount options: %s", mount_options);
 
-	root_mntpt_fd = openat(-1, path, O_RDONLY | O_CLOEXEC | O_PATH | O_DIRECTORY);
-	if (root_mntpt_fd < 0)
-		return log_error_errno(-errno, errno, "Failed to open \"%s\"", path);
-
 	cur_mask = umask(S_IXUSR | S_IXGRP | S_IXOTH);
-	ret = mkdirat(root_mntpt_fd, "dev" , S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+	ret = mkdirat(rootfs->mntpt_fd, "dev" , S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
 	if (ret < 0 && errno != EEXIST) {
 		SYSERROR("Failed to create \"/dev\" directory");
 		ret = -errno;
 		goto reset_umask;
 	}
 
-	ret = safe_mount_beneath_at(root_mntpt_fd, "none", "dev", "tmpfs", 0, mount_options);
+	ret = safe_mount_beneath_at(rootfs->mntpt_fd, "none", "dev", "tmpfs", 0, mount_options);
 	if (ret < 0) {
 		__do_free char *fallback_path = NULL;
 
@@ -1099,7 +1094,7 @@ static int mount_autodev(const char *name, const struct lxc_rootfs *rootfs,
 	/* If we are running on a devtmpfs mapping, dev/pts may already exist.
 	 * If not, then create it and exit if that fails...
 	 */
-	ret = mkdirat(root_mntpt_fd, "dev/pts", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+	ret = mkdirat(rootfs->mntpt_fd, "dev/pts", S_IRWXU | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
 	if (ret < 0 && errno != EEXIST) {
 		SYSERROR("Failed to create directory \"%s\"", path);
 		ret = -errno;