nptl: Set sem_open as a non cancellation point (BZ #15765)

This patch changes sem_open to not act as a cancellation point.
Cancellation is disable at start and reenable in function exit.
It fixes BZ #15765.

Tested on x86_64 and i686.

	[BZ #15765]
	* nptl/Makefile (tests): Add tst-sem16.
	* nptl/tst-sem16.c: New file.
	* nptl/sem_open.c (sem_open): Disable asynchronous cancellation.

1 files changed, 130 insertions, 0 deletions

diff --git a/nptl/tst-sem16.c b/nptl/tst-sem16.c
new file mode 100644
index 0000000000..70067540d3
--- /dev/null
+++ b/nptl/tst-sem16.c
@@ -0,0 +1,130 @@
+/* Test for sem_open cancellation handling: BZ #15765.
+   Copyright (C) 2016 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 <pthread.h>
+#include <sys/mman.h>
+#include <semaphore.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <errno.h>
+#include <stdlib.h>
+
+static sem_t sem;	/* Use to sync with thread start.  */
+static const char pipe_name[] = "/glibc-tst-sem16";
+
+static void
+remove_sem (int status, void *arg)
+{
+  sem_unlink (arg);
+}
+
+static void *
+tf (void *arg)
+{
+  pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0);
+
+  if (sem_wait (&sem) != 0)
+    {
+      printf ("error: sem_wait failed: %m");
+      exit (1);
+    }
+
+  if (pthread_setcancelstate (PTHREAD_CANCEL_ENABLE, 0) != 0)
+    {
+      printf ("error: pthread_setcancelstate failed: %m");
+      exit (1);
+    }
+
+  /* Neither sem_unlink or sem_open should act on thread cancellation.  */
+  sem_unlink (pipe_name);
+  on_exit (remove_sem, (void *) pipe_name);
+
+  sem_t *s = sem_open (pipe_name, O_CREAT, 0600, 1);
+  if (s == SEM_FAILED)
+    {
+      int exit_code;
+      if (errno == ENOSYS || errno == EACCES)
+	exit_code = 77;
+      else
+	exit_code = 1;
+      exit (exit_code);
+    }
+
+  if (pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, 0) != 0)
+    {
+      printf ("error: pthread_setcancelstate failed: %m");
+      exit (1);
+    }
+
+  if (sem_close (s) != 0)
+    {
+      printf ("error: sem_close failed: %m");
+      exit (1);
+    }
+
+  return NULL;
+}
+
+static int
+do_test (void)
+{
+  pthread_t td;
+
+  if (sem_init (&sem, 0, 0))
+    {
+      printf ("error: sem_init failed: %m\n");
+      exit (1);
+    }
+
+  if (pthread_create (&td, NULL, tf, NULL) != 0)
+    {
+      printf ("error: pthread_create failed: %m\n");
+      exit (1);
+    }
+
+  if (pthread_cancel (td) != 0)
+    {
+      printf ("error: pthread_cancel failed: %m\n");
+      exit (1);
+    }
+
+  if (sem_post (&sem) != 0)
+    {
+      printf ("error: sem_post failed: %m\n");
+      exit (1);
+    }
+
+  void *r;
+  if (pthread_join (td, &r) != 0)
+    {
+      printf ("error: pthread_join failed: %m\n");
+      exit (1);
+    }
+
+  if (r == PTHREAD_CANCELED)
+    {
+      puts ("error: pthread_join returned PTHREAD_CANCELED");
+      exit (1);
+    }
+
+  return 0;
+}
+
+#define TEST_FUNCTION do_test ()
+#include <test-skeleton.c>