tst: Provide test for timerfd related functions

This change adds new test to assess functionality of timerfd_*
functions.
It creates new timer (operates on its file descriptor) and checks
if time before and after sleep is between expected values.

2 files changed, 67 insertions, 1 deletions

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 472eab7..0ac1e20 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -106,7 +106,8 @@ tests += tst-clone tst-clone2 tst-clone3 tst-fanotify tst-personality \
 	 tst-quota tst-sync_file_range tst-sysconf-iov_max tst-ttyname \
 	 test-errno-linux tst-memfd_create tst-mlock2 tst-pkey \
 	 tst-rlimit-infinity tst-ofdlocks tst-gettid tst-gettid-kill \
-	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux
+	 tst-tgkill tst-sysvsem-linux tst-sysvmsg-linux tst-sysvshm-linux \
+	 tst-timerfd
 tests-internal += tst-ofdlocks-compat tst-sigcontext-get_pc
 
 CFLAGS-tst-sigcontext-get_pc.c = -fasynchronous-unwind-tables
diff --git a/sysdeps/unix/sysv/linux/tst-timerfd.c b/sysdeps/unix/sysv/linux/tst-timerfd.c
new file mode 100644
index 0000000..c850f7d
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-timerfd.c
@@ -0,0 +1,65 @@
+/* Test for timerfd related functions
+   Copyright (C) 2021 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <time.h>
+#include <support/check.h>
+#include <support/xunistd.h>
+#include <support/timespec.h>
+#include <sys/time.h>
+#include <sys/timerfd.h>
+
+static int
+do_test (void)
+{
+  struct itimerspec settings = { { 2, 0 }, { 2, 0 } };
+  struct itimerspec val1, val2;
+  int fd, ret;
+
+  fd = timerfd_create (CLOCK_REALTIME, 0);
+  if (fd < 0)
+    FAIL_EXIT1 ("*** timerfd_create failed: %m");
+
+  /* Set the timer.  */
+  ret = timerfd_settime (fd, 0, &settings, NULL);
+  if (ret != 0)
+    FAIL_EXIT1 ("*** timerfd_settime failed: %m\n");
+
+  /* Read the timer just before sleep.  */
+  ret = timerfd_gettime (fd, &val1);
+  if (ret != 0)
+    FAIL_EXIT1 ("*** timerfd_gettime failed: %m\n");
+
+  /* Sleep for 1 second.  */
+  ret = usleep (1000000);
+  if (ret != 0)
+    FAIL_EXIT1 ("*** usleep failed: %m\n");
+
+  /* Read the timer just after sleep.  */
+  ret = timerfd_gettime (fd, &val2);
+  if (ret != 0)
+    FAIL_EXIT1 ("*** timerfd_gettime failed: %m\n");
+
+  /* Check difference between timerfd_gettime calls.  */
+  struct timespec r = timespec_sub (val2.it_value, val1.it_value);
+  TEST_COMPARE (support_timespec_check_in_range
+                ((struct timespec) { 1, 0 }, r, 1.0, 1.5), 0);
+
+  return 0;
+}
+
+#include <support/test-driver.c>