/* Check getcontext and setcontext on the context from makecontext

   with shadow stack.

   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 <stdint.h>

#include <stdlib.h>

#include <ucontext.h>

#include <unistd.h>

#include <sys/mman.h>

#include <stdatomic.h>

#include <x86intrin.h>

static ucontext_t ctx[5];

static atomic_int done;

static void

__attribute__((noinline, noclone))

f2 (void)

{

  printf ("start f2\n");

  done++;

  if (setcontext (&ctx[2]) != 0)

    {

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

      exit (EXIT_FAILURE);

    }

}

static void

f1 (void)

{

  printf ("start f1\n");

  if (getcontext (&ctx[2]) != 0)

    {

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

      exit (EXIT_FAILURE);

    }

  if (done)

    exit (EXIT_SUCCESS);

  f2 ();

}

static int

do_test (void)

{

  char st1[32768];

  puts ("making contexts");

  if (getcontext (&ctx[0]) != 0)

    {

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

      exit (EXIT_FAILURE);

    }

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

    {

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

      exit (EXIT_FAILURE);

    }

  ctx[3].uc_stack.ss_sp = st1;

  ctx[3].uc_stack.ss_size = sizeof st1;

  ctx[3].uc_link = &ctx[0];

  makecontext (&ctx[3], (void (*) (void)) f1, 0);

  ctx[1].uc_stack.ss_sp = st1;

  ctx[1].uc_stack.ss_size = sizeof st1;

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

  makecontext (&ctx[1], (void (*) (void)) f1, 0);

  ctx[4].uc_stack.ss_sp = st1;

  ctx[4].uc_stack.ss_size = sizeof st1;

  ctx[4].uc_link = &ctx[0];

  makecontext (&ctx[4], (void (*) (void)) f1, 0);

  /* NB: When shadow stack is enabled, makecontext calls arch_prctl

     with ARCH_CET_ALLOC_SHSTK to allocate a new shadow stack which

     can be unmapped.  The base address and size of the new shadow

     stack are returned in __ssp[1] and __ssp[2].  makecontext is

     called for CTX1, CTX3 and CTX4.  But only CTX1 is used.  New

     shadow stacks are allocated in the order of CTX3, CTX1, CTX4.

     It is very likely that CTX1's shadow stack is placed between

     CTX3 and CTX4.  We munmap CTX3's and CTX4's shadow stacks to

     create gaps above and below CTX1's shadow stack.  We check

     that setcontext CTX1 works correctly in this case.  */

  if (_get_ssp () != 0)

    {

      if (ctx[3].__ssp[1] != 0

	  && munmap ((void *) (uintptr_t) ctx[3].__ssp[1],

		     (size_t) ctx[3].__ssp[2]) != 0)

	{

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

	  exit (EXIT_FAILURE);

	}

      if (ctx[4].__ssp[1] != 0

	  && munmap ((void *) (uintptr_t) ctx[4].__ssp[1],

		     (size_t) ctx[4].__ssp[2]) != 0)

	{

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

	  exit (EXIT_FAILURE);

	}

    }

  if (setcontext (&ctx[1]) != 0)

    {

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

      exit (EXIT_FAILURE);

    }

  exit (EXIT_FAILURE);

}

#include <support/test-driver.c>