1 files changed, 76 insertions, 0 deletions
diff --git a/sysdeps/unix/sysv/linux/tst-ofdlocks.c b/sysdeps/unix/sysv/linux/tst-ofdlocks.c
new file mode 100644
index 0000000000..bd345e9b64
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-ofdlocks.c
@@ -0,0 +1,76 @@
+/* Check non representable OFD locks regions in non-LFS mode (BZ #20251)
+   Copyright (C) 2018 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 2
+   of the License, 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 <unistd.h>
+#include <fcntl.h>
+#include <stdint.h>
+#include <errno.h>
+
+#include <support/temp_file.h>
+#include <support/check.h>
+
+static char *temp_filename;
+static int temp_fd;
+
+static void
+do_prepare (int argc, char **argv)
+{
+  temp_fd = create_temp_file ("tst-ofdlocks.", &temp_filename);
+  TEST_VERIFY_EXIT (temp_fd != -1);
+}
+
+#define PREPARE do_prepare
+
+static int
+do_test (void)
+{
+  /* It first allocates a open file description lock range which can not
+     be represented in a 32 bit struct flock.   */
+  struct flock64 lck64 = {
+    .l_type   = F_WRLCK,
+    .l_whence = SEEK_SET,
+    .l_start  = (off64_t)INT32_MAX + 1024,
+    .l_len    = 1024,
+  };
+  TEST_VERIFY_EXIT (fcntl64 (temp_fd, F_OFD_SETLKW, &lck64) == 0);
+
+  /* Open file description locks placed through the same open file description
+     (either by same file descriptor or a duplicated one created by fork,
+     dup, fcntl F_DUPFD, etc.) overwrites then old lock.  To force a
+     conflicting lock combination, it creates a new file descriptor.  */
+  int fd = open64 (temp_filename, O_RDWR, 0666);
+  TEST_VERIFY_EXIT (fd != -1);
+
+  /* It tries then to allocate another open file descriptior with a valid
+     non-LFS bits struct flock but which will result in a conflicted region
+     which can not be represented in a non-LFS struct flock.  */
+  struct flock lck = {
+    .l_type   = F_WRLCK,
+    .l_whence = SEEK_SET,
+    .l_start  = INT32_MAX - 1024,
+    .l_len    = 4 * 1024,
+  };
+  int r = fcntl (fd, F_OFD_GETLK, &lck);
+  if (sizeof (off_t) != sizeof (off64_t))
+    TEST_VERIFY (r == -1 && errno == EOVERFLOW);
+  else
+    TEST_VERIFY (r == 0);
+
+  return 0;
+}
+
+#include <support/test-driver.c>