conf: use mount_fd() during console mounting

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/conf.c b/src/lxc/conf.c
index 2f6230545573f946ac56b7abe22aa141fb7bbbd1..7ca155e73193d77d8d80f3f2f77d5b86da8b4497 100644 (file)
--- a/src/lxc/conf.c
+++ b/src/lxc/conf.c
@@ -1925,47 +1925,48 @@ static int lxc_setup_ttydir_console(struct lxc_rootfs *rootfs,
                                    const struct lxc_terminal *console,
                                    char *ttydir)
 {
+       __do_close int fd_console = -EBADF, fd_ttydir_console = -EBADF;
        int ret;
        char path[PATH_MAX], lxcpath[PATH_MAX];
        char *rootfs_path = rootfs->path ? rootfs->mount : "";
 
-       /* create rootfs/dev/<ttydir> directory */
-       ret = strnprintf(path, sizeof(path), "%s/dev/%s", rootfs_path, ttydir);
-       if (ret < 0)
-               return -1;
-
-       ret = mkdir(path, 0755);
-       if (ret && errno != EEXIST)
-               return log_error_errno(-errno, errno, "Failed to create \"%s\"", path);
-       DEBUG("Created directory for console and tty devices at \"%s\"", path);
+       /* create dev/<ttydir> */
+       ret = mkdirat(rootfs->dfd_dev, ttydir, 0755);
+       if (ret < 0 && errno != EEXIST)
+               return syserror("Failed to create \"%d/%s\"", rootfs->dfd_dev, ttydir);
+       TRACE("Created directory \"%d/%s\" for console and tty devices", rootfs->dfd_dev, ttydir);
 
-       ret = strnprintf(lxcpath, sizeof(lxcpath), "%s/dev/%s/console", rootfs_path, ttydir);
+       ret = strnprintf(rootfs->buf, sizeof(rootfs->buf), "%s/console", ttydir);
        if (ret < 0)
                return -1;
 
-       ret = mknod(lxcpath, S_IFREG | 0000, 0);
-       if (ret < 0 && errno != EEXIST)
-               return log_error_errno(-errno, errno, "Failed to create \"%s\"", lxcpath);
+       /* create dev/<ttydir>/console */
+       fd_ttydir_console = open_at(rootfs->dfd_dev, rootfs->buf, PROTECT_OPEN | O_CREAT,
+                            PROTECT_LOOKUP_BENEATH, 0000);
+       if (fd_ttydir_console < 0)
+               return syserror("Failed to create console");
 
-       ret = strnprintf(path, sizeof(path), "%s/dev/console", rootfs_path);
+       ret = strnprintf(rootfs->buf, sizeof(rootfs->buf), "%s/dev/console", rootfs_path);
        if (ret < 0)
                return -1;
 
-       if (file_exists(path)) {
-               ret = lxc_unstack_mountpoint(path, false);
+       if (file_exists(rootfs->buf)) {
+               ret = lxc_unstack_mountpoint(rootfs->buf, false);
                if (ret < 0)
-                       return log_error_errno(-ret, errno, "Failed to unmount \"%s\"", path);
+                       return log_error_errno(-ret, errno, "Failed to unmount \"%s\"", rootfs->buf);
                else
-                       DEBUG("Cleared all (%d) mounts from \"%s\"", ret, path);
+                       DEBUG("Cleared all (%d) mounts from \"%s\"", ret, rootfs->buf);
        }
 
-       ret = mknod(path, S_IFREG | 0000, 0);
-       if (ret < 0 && errno != EEXIST)
-               return log_error_errno(-errno, errno, "Failed to create console");
+       /* create dev/<ttydir>/console */
+       fd_console = open_at(rootfs->dfd_dev, "console", PROTECT_OPEN | O_CREAT,
+                            PROTECT_LOOKUP_BENEATH, 0000);
+       if (fd_console < 0)
+               return syserror("Failed to create console");
 
        ret = fchmod(console->pty, 0620);
        if (ret < 0)
-               return log_error_errno(-errno, errno, "Failed to set mode \"0%o\" to \"%s\"", 0620, console->name);
+               return syserror("Failed to set mode \"0%o\" to \"%s\"", 0620, console->name);
 
        /* bind mount console->name to '/dev/<ttydir>/console' */
        if (can_use_mount_api()) {
@@ -1975,7 +1976,7 @@ static int lxc_setup_ttydir_console(struct lxc_rootfs *rootfs,
 
                ret = lxc_bind_mount_console(console, rootfs->dfd_dev, rootfs->buf);
        } else {
-               ret = safe_mount(console->name, lxcpath, "none", MS_BIND, 0, rootfs_path);
+               ret = mount_fd(console->pty, fd_ttydir_console, "none", MS_BIND, 0);
        }
        if (ret < 0)
                return log_error_errno(ret, errno, "Failed to mount %d(%s) on \"%s\"", console->pty, console->name, lxcpath);
@@ -1989,7 +1990,7 @@ static int lxc_setup_ttydir_console(struct lxc_rootfs *rootfs,
                                    PROTECT_OPATH_FILE, PROTECT_LOOKUP_BENEATH,
                                    0, false);
        } else {
-               ret = safe_mount(lxcpath, path, "none", MS_BIND, 0, rootfs_path);
+               ret = mount_fd(fd_ttydir_console, fd_console, "none", MS_BIND, 0);
        }
        if (ret < 0)
                return log_error_errno(-1, errno, "Failed to mount \"%s\" on \"%s\"", console->name, lxcpath);