[3/5] Add another test for setcontext

diff --git a/stdlib/Makefile b/stdlib/Makefile
index ffd9180471..75021e6897 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -85,7 +85,7 @@  tests		:= tst-strtol tst-strtod testmb testrand testsort testdiv   \
 		   test-at_quick_exit-race test-cxa_atexit-race             \
 		   test-on_exit-race test-dlclose-exit-race 		    \
 		   tst-makecontext-align test-bz22786 tst-strtod-nan-sign \
-		   tst-swapcontext1 tst-swapcontext2
+		   tst-swapcontext1 tst-swapcontext2 tst-setcontext4
 
 tests-internal	:= tst-strtod1i tst-strtod3 tst-strtod4 tst-strtod5i \
 		   tst-tls-atexit tst-tls-atexit-nodelete
diff --git a/stdlib/tst-setcontext4.c b/stdlib/tst-setcontext4.c
new file mode 100644
index 0000000000..64d3fc9137
--- /dev/null
+++ b/stdlib/tst-setcontext4.c
@@ -0,0 +1,217 @@ 
+/* Testcase checks, if setcontext(), swapcontext() restores signal-mask
+   and if pending signals are delivered after those calls.
+   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 <stdio.h>
+#include <stdlib.h>
+#include <sys/types.h>
+#include <signal.h>
+#include <ucontext.h>
+#include <unistd.h>
+
+volatile int global;
+volatile sig_atomic_t handlerCalled;
+
+static void
+check (const char *funcName)
+{
+  sigset_t set;
+
+  /* check if SIGUSR2 is unblocked after setcontext-call.  */
+  sigprocmask (SIG_BLOCK, NULL, &set);
+
+  if (sigismember (&set, SIGUSR2) != 0)
+    {
+      printf ("FAIL: SIGUSR2 is blocked after %s.\n", funcName);
+      exit (1);
+    }
+
+  if (sigismember (&set, SIGUSR1) != 1)
+    {
+      printf ("FAIL: SIGUSR1 is not blocked after %s.\n", funcName);
+      exit (1);
+    }
+}
+
+static void
+signalmask (int how, int signum)
+{
+  sigset_t set;
+  sigemptyset (&set);
+  sigaddset (&set, signum);
+  if (sigprocmask (how, &set, NULL) != 0)
+    {
+      printf ("FAIL: sigprocmaks (%d, %d, NULL): %m\n", how, signum);
+      exit (1);
+    }
+}
+
+static void
+signalpending (int signum, const char *msg)
+{
+  sigset_t set;
+  sigemptyset (&set);
+  if (sigpending (&set) != 0)
+    {
+      printf ("FAIL: sigpending: %m\n");
+      exit (1);
+    }
+  if (sigismember (&set, SIGUSR2) != 1)
+    {
+      printf ("FAIL: Signal %d is not pending %s\n", signum, msg);
+      exit (1);
+    }
+}
+
+static void
+handler (int __attribute__ ((unused)) signum)
+{
+  handlerCalled ++;
+}
+
+static int
+do_test (void)
+{
+  ucontext_t ctx, oldctx;
+  struct sigaction action;
+  pid_t pid;
+
+  pid = getpid ();
+
+  /* unblock SIGUSR2 */
+  signalmask (SIG_UNBLOCK, SIGUSR2);
+
+  /* block SIGUSR1 */
+  signalmask (SIG_BLOCK, SIGUSR1);
+
+  /* register handler for SIGUSR2  */
+  action.sa_flags = 0;
+  action.sa_handler = handler;
+  sigemptyset (&action.sa_mask);
+  sigaction (SIGUSR2, &action, NULL);
+
+  if (getcontext (&ctx) != 0)
+    {
+      printf ("FAIL: getcontext: %m\n");
+      exit (1);
+    }
+
+  global++;
+
+  if (global == 1)
+    {
+      puts ("after getcontext");
+
+      /* block SIGUSR2  */
+      signalmask (SIG_BLOCK, SIGUSR2);
+
+      /* send SIGUSR2 to me  */
+      handlerCalled = 0;
+      kill (pid, SIGUSR2);
+
+      /* was SIGUSR2 handler called?  */
+      if (handlerCalled != 0)
+	{
+	  puts ("FAIL: signal handler was called, but signal was blocked.");
+	  exit (1);
+	}
+
+      /* is SIGUSR2 pending?  */
+      signalpending (SIGUSR2, "before setcontext");
+
+      /* SIGUSR2 will be unblocked by setcontext-call.  */
+      if (setcontext (&ctx) != 0)
+	{
+	  printf ("FAIL: setcontext: %m\n");
+	  exit (1);
+	}
+    }
+  else if (global == 2)
+    {
+      puts ("after setcontext");
+
+      /* check SIGUSR1/2  */
+      check ("setcontext");
+
+      /* was SIGUSR2 handler called? */
+      if (handlerCalled != 1)
+	{
+	  puts ("FAIL: signal handler was not called after setcontext.");
+	  exit (1);
+	}
+
+      /* block SIGUSR2 */
+      signalmask (SIG_BLOCK, SIGUSR2);
+
+      /* send SIGUSR2 to me  */
+      handlerCalled = 0;
+      kill (pid, SIGUSR2);
+
+      /* was SIGUSR2 handler called?  */
+      if (handlerCalled != 0)
+	{
+	  puts ("FAIL: signal handler was called, but signal was blocked.");
+	  exit (1);
+	}
+
+      /* is SIGUSR2 pending?  */
+      signalpending (SIGUSR2, "before swapcontext");
+
+      if (swapcontext (&oldctx, &ctx) != 0)
+	{
+	  printf ("FAIL: swapcontext: %m\n");
+	  exit (1);
+	}
+
+      puts ("FAIL: returned from (&oldctx, &ctx)");
+      exit (1);
+    }
+  else if ( global != 3 )
+    {
+      puts ("FAIL: 'global' not incremented three times");
+      exit (1);
+    }
+
+  puts ("after swapcontext");
+  /* check SIGUSR1/2  */
+  check ("swapcontext");
+
+  /* was SIGUSR2 handler called? */
+  if (handlerCalled != 1)
+    {
+      puts ("FAIL: signal handler was not called after swapcontext.");
+      exit (1);
+    }
+
+  /* check sigmask in old context of swapcontext-call  */
+  if (sigismember (&oldctx.uc_sigmask, SIGUSR2) != 1)
+    {
+      puts ("FAIL: SIGUSR2 is not blocked in oldctx.uc_sigmask.");
+      exit (1);
+    }
+
+  if (sigismember (&oldctx.uc_sigmask, SIGUSR1) != 1)
+    {
+      puts ("FAIL: SIGUSR1 is not blocked in oldctx.uc_sigmaks.");
+      exit (1);
+    }
+
+  return 0;
+}
+
+#include <support/test-driver.c>