/* Make sure longjmp fortification catches bad signal stacks.

   Copyright (C) 2013-2018 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 <setjmp.h>

#include <signal.h>

#include <string.h>

static int do_test (void);

#define TEST_FUNCTION do_test ()

#include "../test-skeleton.c"

static char buf[SIGSTKSZ * 4];

static jmp_buf jb;

static void

handler (int sig)

{

  if (sig == SIGUSR1)

    {

      if (setjmp (jb) != 0)

	{

	  puts ("setjmp should not have been called");

	  kill (getpid (), SIGTERM);

	}

    }

  else if (sig == SIGABRT)

    {

      /* Yeah it worked.  */

      _exit (0);

    }

}

static int

do_test (void)

{

  stack_t ss;

  set_fortify_handler (handler);

  /* Create a valid signal stack and enable it.  */

  ss.ss_sp = buf;

  ss.ss_size = sizeof (buf);

  ss.ss_flags = 0;

  if (sigaltstack (&ss, NULL) < 0)

    {

      printf ("first sigaltstack failed: %m\n");

      return 1;

    }

  /* Trigger the signal handler which will create a jmpbuf that points to the

     end of the signal stack.  */

  signal (SIGUSR1, handler);

  kill (getpid (), SIGUSR1);

  /* Shrink the signal stack so the jmpbuf is now invalid.

     We adjust the start & end to handle stacks that grow up & down.  */

  ss.ss_sp = buf + sizeof (buf) / 2;

  ss.ss_size = sizeof (buf) / 4;

  if (sigaltstack (&ss, NULL) < 0)

    {

      printf ("second sigaltstack failed: %m\n");

      return 1;

    }

  /* This should fail.  */

  longjmp (jb, 1);

  puts ("longjmp returned and shouldn't");

  return 1;

}