source: kBuild/vendor/grep/current/gnulib-tests/test-sigsegv-catch-segv2.c@ 3630

/* Test that the handler can be exited multiple times.
   Copyright (C) 2002-2021 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program 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 General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <https://www.gnu.org/licenses/>.  */

/* Written by Bruno Haible.  */

#include <config.h>

/* Specification.  */
#include "sigsegv.h"

#include <stdint.h>
#include <stdio.h>

#if HAVE_SIGSEGV_RECOVERY

# if defined _WIN32 && !defined __CYGWIN__
  /* Windows doesn't have sigset_t.  */
  typedef int sigset_t;
#  define sigemptyset(set)
#  define sigprocmask(how,set,oldset)
# endif

# include "mmap-anon-util.h"
# include <stdlib.h> /* for abort, exit */
# include <signal.h>
# include <setjmp.h>

# if SIGSEGV_FAULT_ADDRESS_ALIGNMENT > 1UL
#  include <unistd.h>
#  define SIGSEGV_FAULT_ADDRESS_ROUNDOFF_BITS (getpagesize () - 1)
# else
#  define SIGSEGV_FAULT_ADDRESS_ROUNDOFF_BITS 0
# endif

jmp_buf mainloop;
sigset_t mainsigset;

volatile int pass = 0;
uintptr_t page;

volatile int handler_called = 0;

static void
handler_continuation (void *arg1, void *arg2, void *arg3)
{
  longjmp (mainloop, pass);
}

int
handler (void *fault_address, int serious)
{
  handler_called++;
  if (handler_called > 10)
    abort ();
  if (fault_address
      != (void *)((page + 0x678 + 8 * pass) & ~SIGSEGV_FAULT_ADDRESS_ROUNDOFF_BITS))
    abort ();
  pass++;
  printf ("Fault %d caught.\n", pass);
  sigprocmask (SIG_SETMASK, &mainsigset, NULL);
  return sigsegv_leave_handler (handler_continuation, NULL, NULL, NULL);
}

void
crasher (uintptr_t p)
{
  *(volatile int *) (p + 0x678 + 8 * pass) = 42;
}

int
main ()
{
  int prot_unwritable;
  void *p;
  sigset_t emptyset;

  /* Preparations.  */
# if !HAVE_MAP_ANONYMOUS
  zero_fd = open ("/dev/zero", O_RDONLY, 0644);
# endif

# if defined __linux__ && defined __sparc__
  /* On Linux 2.6.26/SPARC64, PROT_READ has the same effect as
     PROT_READ | PROT_WRITE.  */
  prot_unwritable = PROT_NONE;
# else
  prot_unwritable = PROT_READ;
# endif

  /* Setup some mmaped memory.  */
  p = mmap_zeromap ((void *) 0x12340000, 0x4000);
  if (p == (void *)(-1))
    {
      fprintf (stderr, "mmap_zeromap failed.\n");
      exit (2);
    }
  page = (uintptr_t) p;

  /* Make it read-only.  */
  if (mprotect ((void *) page, 0x4000, prot_unwritable) < 0)
    {
      fprintf (stderr, "mprotect failed.\n");
      exit (2);
    }

  /* Install the SIGSEGV handler.  */
  if (sigsegv_install_handler (&handler) < 0)
    exit (2);

  /* Save the current signal mask.  */
  sigemptyset (&emptyset);
  sigprocmask (SIG_BLOCK, &emptyset, &mainsigset);

  /* Provoke two SIGSEGVs in a row.  */
  switch (setjmp (mainloop))
    {
    case 0: case 1:
      printf ("Doing SIGSEGV pass %d.\n", pass + 1);
      crasher (page);
      printf ("no SIGSEGV?!\n"); exit (1);
    case 2:
      break;
    default:
      abort ();
    }

  /* Test passed!  */
  printf ("Test passed.\n");
  return 0;
}

#else

int
main ()
{
  return 77;
}

#endif