[PATCH] tst: Provide test for timerfd related functions

[Lukasz Majewski]

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.
---
 sysdeps/unix/sysv/linux/Makefile      |   3 +-
 sysdeps/unix/sysv/linux/tst-timerfd.c | 100 ++++++++++++++++++++++++++
 2 files changed, 102 insertions(+), 1 deletion(-)
 create mode 100644 sysdeps/unix/sysv/linux/tst-timerfd.c

diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
index 6df4779126..7503b356c8 100644
--- a/sysdeps/unix/sysv/linux/Makefile
+++ b/sysdeps/unix/sysv/linux/Makefile
@@ -107,7 +107,8 @@ 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 0000000000..6ec379ff71
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/tst-timerfd.c
@@ -0,0 +1,100 @@
+/* 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 <sys/time.h>
+#include <sys/timerfd.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.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)
+    {
+	    printf ("*** timerfd_create failed: %d\n", fd);
+      return fd;
+    }
+
+  /* Set the timer.  */
+  ret = timerfd_settime(fd, 0, &settings, NULL);
+  if (ret != 0)
+    {
+      printf ("*** timerfd_settime failed: %m\n");
+      goto err;
+    }
+
+  /* Read the timer just before sleep.  */
+  ret = timerfd_gettime(fd, &val1);
+  if (ret != 0)
+    {
+      printf ("*** timerfd_gettime failed: %m\n");
+      goto err;
+    }
+
+  /* Sleep for 1 second.  */
+  ret = usleep(1000000);
+  if (ret != 0)
+    {
+      printf ("*** usleep failed: %m\n");
+      goto err;
+    }
+
+  /* Read the timer just after sleep.  */
+  ret = timerfd_gettime(fd, &val2);
+  if (ret != 0)
+    {
+      printf ("*** timerfd_gettime failed: %m\n");
+      goto err;
+    }
+
+  /* Check difference between timerfd_gettime() calls.  */
+  long long int diff = val1.it_value.tv_sec - val2.it_value.tv_sec;
+  diff *= 1000000000;
+  diff += val1.it_value.tv_nsec - val2.it_value.tv_nsec;
+  diff -= 1000000000;
+  diff = abs(diff);
+  if (diff > 100000000)
+    {
+      printf ("*** The diff between timerfd calls (%lld) is wrong!\n",
+              diff);
+      goto err;
+    }
+
+  ret = close(fd);
+  if (ret != 0)
+	  {
+      printf ("*** fd close failed: %m\n");
+      goto err;
+	  }
+
+  return 0;
+
+ err:
+  close (fd);
+  return ret;
+}
+
+#include <support/test-driver.c>
-- 
2.20.1