virFileIsSharedFSType: Detect direct mount points

If the given path is already a mount point (e.g. a bind mount of
a file, or simply a direct mount point of a FS), then our code
fails to detect that because the first thing it does is cutting
off part after last slash '/'.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NJiri Denemark <jdenemar@redhat.com>

src/util/virfile.c

@@ -3534,7 +3534,7 @@ virFileIsSharedFSType(const char *path,
                       int fstypes)
 {
     VIR_AUTOFREE(char *) dirpath = NULL;
-    char *p;
+    char *p = NULL;
     struct statfs sb;
     int statfs_ret;
     long long f_type = 0;
@@ -3542,8 +3542,9 @@ virFileIsSharedFSType(const char *path,
     if (VIR_STRDUP(dirpath, path) < 0)
         return -1;
 
-    do {
+    statfs_ret = statfs(dirpath, &sb);
 
+    while ((statfs_ret < 0) && (p != dirpath)) {
         /* Try less and less of the path until we get to a
          * directory we can stat. Even if we don't have 'x'
          * permission on any directory in the path on the NFS
@@ -3564,8 +3565,7 @@ virFileIsSharedFSType(const char *path,
             *p = '\0';
 
         statfs_ret = statfs(dirpath, &sb);
-
-    } while ((statfs_ret < 0) && (p != dirpath));
+    }
 
     if (statfs_ret < 0) {
         virReportSystemError(errno,

tests/virfiletest.c

@@ -453,8 +453,7 @@ mymain(void)
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts1.txt", "/boot/vmlinuz", false);
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts2.txt", "/run/user/501/gvfs/some/file", false);
     DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/nfs/file", true);
-    /* TODO Detect bind mounts */
-    DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/nfs/blah", true);
+    DO_TEST_FILE_IS_SHARED_FS_TYPE("mounts3.txt", "/nfs/blah", false);
 
     return ret != 0 ? EXIT_FAILURE : EXIT_SUCCESS;
 }