mountpoint: support symbolic and relative paths

Reported-by: Dave Reisner <dreisner@archlinux.org>
Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/sys-utils/mountpoint.c b/sys-utils/mountpoint.c
index 1182f7c3bda108211ca3c436790a31b2bcd253d7..5cc833d4f8797e0b48f07192fcc96bcc9ae37eca 100644 (file)
--- a/sys-utils/mountpoint.c
+++ b/sys-utils/mountpoint.c
@@ -44,6 +44,7 @@ static dev_t dir_to_device(const char *spec)
 {
        struct libmnt_table *tb = mnt_new_table_from_file("/proc/self/mountinfo");
        struct libmnt_fs *fs;
+       struct libmnt_cache *cache;
        dev_t res = 0;
 
        if (!tb) {
@@ -52,13 +53,17 @@ static dev_t dir_to_device(const char *spec)
                 * is independent on /proc, but not able to detect bind mounts.
                 */
                struct stat pst, st;
-               char buf[PATH_MAX];
+               char buf[PATH_MAX], *cn;
                int len;
 
                if (stat(spec, &st) != 0)
                        return 0;
 
-               len = snprintf(buf, sizeof(buf), "%s/..", spec);
+               cn = mnt_resolve_path(spec, NULL);      /* canonicalize */
+
+               len = snprintf(buf, sizeof(buf), "%s/..", cn ? cn : spec);
+               free(cn);
+
                if (len < 0 || (size_t) len + 1 > sizeof(buf))
                        return 0;
                if (stat(buf, &pst) !=0)
@@ -71,11 +76,16 @@ static dev_t dir_to_device(const char *spec)
                return 0;
        }
 
+       /* to canonicalize all necessary paths */
+       cache = mnt_new_cache();
+       mnt_table_set_cache(tb, cache);
+
        fs = mnt_table_find_target(tb, spec, MNT_ITER_BACKWARD);
        if (fs && mnt_fs_get_target(fs))
                res = mnt_fs_get_devno(fs);
 
        mnt_free_table(tb);
+       mnt_free_cache(cache);
        return res;
 }