/* Copyright (C) 2003-2018 Free Software Foundation, Inc.

   This file is part of the GNU C Library.

   Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.

   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 <errno.h>

#include <error.h>

#include <limits.h>

#include <pthread.h>

#include <stdio.h>

#include <stdlib.h>

#include <ucontext.h>

#define N	4

#if __WORDSIZE == 64

#define GUARD_PATTERN 0xdeadbeafdeadbeaf

#else

#define GUARD_PATTERN 0xdeadbeaf

#endif

typedef struct {

       ucontext_t uctx;

       unsigned long	guard[3];

   } tst_context_t;

static char stacks[N][2 * PTHREAD_STACK_MIN];

static tst_context_t ctx[N][2];

static volatile int failures;

static void

fct (long int n)

{

  char on_stack[1];

  /* Just to use the thread local descriptor.  */

  printf ("%ld: in %s now, on_stack = %p\n", n, __FUNCTION__, on_stack);

  errno = 0;

  if (ctx[n][1].uctx.uc_link != &ctx[n][0].uctx)

    {

      printf ("context[%ld][1] uc_link damaged, = %p\n", n,

	      ctx[n][1].uctx.uc_link);

      exit (1);

    }

  if ((ctx[n][0].guard[0] != GUARD_PATTERN)

  ||  (ctx[n][0].guard[1] != GUARD_PATTERN)

  ||  (ctx[n][0].guard[2] != GUARD_PATTERN))

    {

      printf ("%ld: %s context[0] overflow detected!\n", n, __FUNCTION__);

      ++failures;

    }

  if ((ctx[n][1].guard[0] != GUARD_PATTERN)

  ||  (ctx[n][1].guard[1] != GUARD_PATTERN)

  ||  (ctx[n][1].guard[2] != GUARD_PATTERN))

    {

      printf ("%ld: %s context[1] overflow detected!\n", n, __FUNCTION__);

      ++failures;

    }

  if (n < 0 || n >= N)

    {

      printf ("%ld out of range\n", n);

      exit (1);

    }

  if (on_stack < stacks[n] || on_stack >= stacks[n] + sizeof (stacks[0]))

    {

      printf ("%ld: on_stack not on appropriate stack\n", n);

      exit (1);

    }

}

static void *

tf (void *arg)

{

  int n = (int) (long int) arg;

  ctx[n][0].guard[0] = GUARD_PATTERN;

  ctx[n][0].guard[1] = GUARD_PATTERN;

  ctx[n][0].guard[2] = GUARD_PATTERN;

  ctx[n][1].guard[0] = GUARD_PATTERN;

  ctx[n][1].guard[1] = GUARD_PATTERN;

  ctx[n][1].guard[2] = GUARD_PATTERN;

  if (getcontext (&ctx[n][1].uctx) != 0)

    {

      printf ("%d: cannot get context: %m\n", n);

      exit (1);

    }

  printf ("%d: %s: before makecontext\n", n, __FUNCTION__);

  ctx[n][1].uctx.uc_stack.ss_sp = stacks[n];

  ctx[n][1].uctx.uc_stack.ss_size = sizeof (stacks[n]);

  ctx[n][1].uctx.uc_link = &ctx[n][0].uctx;

  makecontext (&ctx[n][1].uctx, (void (*) (void)) fct, 1, (long int) n);

  printf ("%d: %s: before swapcontext\n", n, __FUNCTION__);

  if (swapcontext (&ctx[n][0].uctx, &ctx[n][1].uctx) != 0)

    {

      ++failures;

      printf ("%d: %s: swapcontext failed\n", n, __FUNCTION__);

    }

  else

    printf ("%d: back in %s\n", n, __FUNCTION__);

  return NULL;

}

static volatile int global;

static int

do_test (void)

{

  int n;

  pthread_t th[N];

  ucontext_t mctx;

  puts ("making contexts");

  if (getcontext (&mctx) != 0)

    {

      if (errno == ENOSYS)

	{

	  puts ("context handling not supported");

	  exit (0);

	}

      printf ("%s: getcontext: %m\n", __FUNCTION__);

      exit (1);

    }

  /* Play some tricks with this context.  */

  if (++global == 1)

    if (setcontext (&mctx) != 0)

      {

	puts ("setcontext failed");

	exit (1);

      }

  if (global != 2)

    {

      puts ("global not incremented twice");

      exit (1);

    }

  puts ("global OK");

  pthread_attr_t at;

  if (pthread_attr_init (&at) != 0)

    {

      puts ("attr_init failed");

      return 1;

    }

  if (pthread_attr_setstacksize (&at, 1 * 1024 * 1024) != 0)

    {

      puts ("attr_setstacksize failed");

      return 1;

    }

  for (n = 0; n < N; ++n)

    if (pthread_create (&th[n], &at, tf, (void *) (long int) n) != 0)

      {

	puts ("create failed");

	exit (1);

      }

  if (pthread_attr_destroy (&at) != 0)

    {

      puts ("attr_destroy failed");

      return 1;

    }

  for (n = 0; n < N; ++n)

    if (pthread_join (th[n], NULL) != 0)

      {

	puts ("join failed");

	exit (1);

      }

  return failures;

}

#define TEST_FUNCTION do_test ()

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