hust testsuite: fix a false positive

[oweals/busybox.git] / miscutils / mountpoint.c

diff --git a/miscutils/mountpoint.c b/miscutils/mountpoint.c
index b541ce28c35d1cb05c911fb8b631d8bb6805895a..7041f7c59c2e6f6c80a44d02c1b44d63eff2a96d 100644 (file)
--- a/miscutils/mountpoint.c
+++ b/miscutils/mountpoint.c
@@ -4,11 +4,26 @@
  *
  * Copyright (C) 2005 Bernhard Reutner-Fischer
  *
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  *
  * Based on sysvinit's mountpoint
  */
 
+//usage:#define mountpoint_trivial_usage
+//usage:       "[-q] <[-dn] DIR | -x DEVICE>"
+//usage:#define mountpoint_full_usage "\n\n"
+//usage:       "Check if the directory is a mountpoint\n"
+//usage:     "\n       -q      Quiet"
+//usage:     "\n       -d      Print major/minor device number of the filesystem"
+//usage:     "\n       -n      Print device name of the filesystem"
+//usage:     "\n       -x      Print major/minor device number of the blockdevice"
+//usage:
+//usage:#define mountpoint_example_usage
+//usage:       "$ mountpoint /proc\n"
+//usage:       "/proc is not a mountpoint\n"
+//usage:       "$ mountpoint /sys\n"
+//usage:       "/sys is a mountpoint\n"
+
 #include "libbb.h"
 
 int mountpoint_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@@ -55,8 +70,17 @@ int mountpoint_main(int argc UNUSED_PARAM, char **argv)
 
                        if (opt & OPT_d)
                                printf("%u:%u\n", major(st_dev), minor(st_dev));
-                       if (opt & OPT_n)
-                               printf("%s %s\n", find_block_device(arg), arg);
+                       if (opt & OPT_n) {
+                               const char *d = find_block_device(arg);
+                               /* name is undefined, but device is mounted -> anonymous superblock! */
+                               /* happens with btrfs */
+                               if (!d) {
+                                       d = "UNKNOWN";
+                                       /* TODO: iterate /proc/mounts, or /proc/self/mountinfo
+                                        * to find out the device name */
+                               }
+                               printf("%s %s\n", d, arg);
+                       }
                        if (!(opt & (OPT_q | OPT_d | OPT_n)))
                                printf("%s is %sa mountpoint\n", arg, is_not_mnt ? "not " : "");
                        return is_not_mnt;