/* Test the stack guard.

   Copyright (C) 2000-2018 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/>.  */

#define _GNU_SOURCE

#include <pthread.h>

#include <assert.h>

#include <unistd.h>

#include <errno.h>

#include <string.h>

#include <stdio.h>

size_t stacksize;

void *

thr (void *arg)

{

  int i;

  char *foo;

  foo = alloca (3 * stacksize / 4);

  for (i = 0; i < sizeof foo; i++)

    foo[i] = -1;

  return (void *) 1;

}

int

main (int argc, char *argv[])

{

  error_t err;

  pid_t child;

  child = fork ();

  switch (child)

    {

    case -1:

      error (1, errno, "fork");

      break;

    case 0:

      {

	pthread_attr_t attr;

	pthread_t tid;

	void *ret;

	err = pthread_attr_init (&attr);

	assert_perror (err);

	err = pthread_attr_getstacksize (&attr, &stacksize);

	assert_perror (err);

	err = pthread_attr_setguardsize (&attr, stacksize / 2);

	if (err == ENOTSUP)

	  {

	    printf ("Stack guard attribute not supported.\n");

	    return 1;

	  }

	assert_perror (err);

	err = pthread_create (&tid, &attr, thr, 0);

	assert_perror (err);

	err = pthread_attr_destroy (&attr);

	assert_perror (err);

	err = pthread_join (tid, &ret;;

	/* Should never be successful.  */

	printf ("Thread did not segfault!?!\n");

	assert_perror (err);

	return 0;

      }

    default:

      {

	pid_t pid;

	int status;

	pid = waitpid (child, &status, 0);

	printf ("pid = %d; child = %d; status = %d\n", pid, child, status);

	assert (pid == child);

	assert (status != 0);

      }

    }

  return 0;

}