Add tst-sigaction.c to test BZ #23069

This simple test uses sigaction to define a signal handler. It then
uses sigaction again to fetch the information about the same signal
handler, and check that they are consistent. This is enough to detect
mismatches between struct kernel_sigaction and the kernel version of
struct sigaction, like in BZ #23069.

Changelog:
       * signal/tst-sigaction.c: New file to test BZ #23069.
       * signal/Makefile (tests): Fix indentation. Add tst-sigaction.

ChangeLog

@@ -1,3 +1,8 @@
+2018-04-26  Aurelien Jarno  <aurelien@aurel32.net>
+
+	* signal/tst-sigaction.c: New file to test BZ #23069.
+	* signal/Makefile (tests): Fix indentation. Add tst-sigaction.
+
 2018-04-26  Tulio Magno Quites Machado Filho  <tuliom@linux.ibm.com>
 
 	[BZ #22766]

signal/Makefile

@@ -46,7 +46,7 @@ routines	:= signal raise killpg \
 		   sighold sigrelse sigignore sigset
 
 tests		:= tst-signal tst-sigset tst-sigsimple tst-raise tst-sigset2 \
-  tst-sigwait-eintr \
+		   tst-sigwait-eintr tst-sigaction \
 
 include ../Rules
 

signal/tst-sigaction.c

@@ -0,0 +1,56 @@
+/* Test sigaction regression for BZ #23069.
+   Copyright (C) 2018 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
+   <http://www.gnu.org/licenses/>.  */
+
+#include <signal.h>
+#include <unistd.h>
+
+#include <support/check.h>
+
+static void
+my_sig_handler (int signum)
+{
+}
+
+static int
+do_test (void)
+{
+  /* Define a simple signal handler */
+  struct sigaction act;
+  act.sa_handler = my_sig_handler;
+  act.sa_flags = 0;
+  sigemptyset (&act.sa_mask);
+
+  /* Set it as SIGUSR1 signal handler */
+  TEST_VERIFY_EXIT (sigaction (SIGUSR1, &act, NULL) == 0);
+
+  /* Get SIGUSR1 signal handler */
+  TEST_VERIFY_EXIT (sigaction (SIGUSR1, NULL, &act) == 0);
+
+  /* Check it is consistent with the defined one */
+  TEST_VERIFY (act.sa_handler == my_sig_handler);
+  TEST_VERIFY (!(act.sa_flags & SA_RESETHAND));
+
+  for (int i = 1; i < _NSIG; i++)
+    {
+      TEST_VERIFY (!sigismember (&act.sa_mask, i));
+    }
+
+  return 0;
+}
+
+#include <support/test-driver.c>