1 files changed, 69 insertions, 0 deletions
diff --git a/tests/ckmtime.c b/tests/ckmtime.c
new file mode 100644
index 0000000..9fde42d
--- /dev/null
+++ b/tests/ckmtime.c
@@ -0,0 +1,69 @@
+/* Check if filesystem timestamps are consistent with the system time.
+   Copyright (C) 2016 Free Software Foundation, Inc.
+      
+   This program is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 3, or (at your option) any later
+   version.
+
+   This program is distributed in the hope that it will be useful, but
+   WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General
+   Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with this program.  If not, see <http://www.gnu.org/licenses/>.
+*/
+#include <config.h>
+#include <sys/stat.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <stat-time.h>
+#include <timespec.h>
+
+#define TEMPLATE "ckmtime.XXXXXX"
+#define BILLION 1000000000
+
+/* Some filesystems can slightly offset the timestamps of newly created files.
+   To compensate for it, tar testsuite waits at least 1 second before creating
+   next level of incremental backups.
+
+   However, NFS mounts can offset the timestamps by bigger amounts.  
+   
+   This program returns with success (0) if a newly created file is assigned
+   mtime matching the system time to the nearest second.
+*/
+int
+main (int argc, char **argv)
+{
+  int fd;
+  char name[sizeof(TEMPLATE)];
+  struct stat st;
+  struct timespec ts, td;
+  double diff;
+  
+  gettime (&ts);
+  
+  strcpy (name, TEMPLATE);
+  umask (077);
+  fd = mkstemp (name);
+  assert (fd != -1);
+  unlink (name);
+  assert (fstat (fd, &st) == 0);
+  close (fd);
+
+  td = timespec_sub (get_stat_mtime (&st), ts);
+  diff = td.tv_sec * BILLION + td.tv_nsec;
+  if (diff < 0)
+    diff = - diff;
+  if (diff / BILLION >= 1)
+    {
+      fprintf (stderr, "file timestamp unreliable\n");
+      return 1;
+    }
+  return 0;
+}