/* BZ #17977 _res_hconf_reorder_addrs test.

   Copyright (C) 2015-2018 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 <errno.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <time.h>

#include <dlfcn.h>

#include <pthread.h>

#include <netdb.h>

#include <netinet/in.h>

#include <sys/socket.h>

static struct timespec ts;

/* The first thread that gets a lock in _res_hconf_reorder_addrs()

   should hold the lock long enough to make two other threads blocked.

   This is achieved by slowing down realloc(3) that is called several times

   by _res_hconf_reorder_addrs().  */

void *

realloc (void *ptr, size_t len)

{

  static void *(*fun) (void *, size_t);

  if (!fun)

    fun = dlsym (RTLD_NEXT, "realloc");

  if (ts.tv_nsec)

    nanosleep (&ts, NULL);

  return (*fun) (ptr, len);

}

static void *

resolve (void *arg)

{

  struct in_addr addr;

  struct hostent ent;

  struct hostent *result;

  int err;

  char buf[1024];

  addr.s_addr = htonl (INADDR_LOOPBACK);

  (void) gethostbyaddr_r ((void *) &addr, sizeof (addr), AF_INET,

		          &ent, buf, sizeof (buf), &result, &err;;

  return arg;

}

static int

do_test (void)

{

  #define N 3

  pthread_t thr[N];

  unsigned int i;

  int result = 0;

  /* turn on realloc slowdown */

  ts.tv_nsec = 100000000;

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

    {

      int rc = pthread_create (&thr[i], NULL, resolve, NULL);

      if (rc)

	{

	  printf ("pthread_create: %s\n", strerror(rc));

	  exit (1);

	}

    }

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

    {

      void *retval;

      int rc = pthread_join (thr[i], &retval);

      if (rc)

	{

	  printf ("pthread_join: %s\n", strerror(rc));

	  exit (1);

	}

      if (retval)

	{

	  printf ("thread %u exit status %p\n", i, retval);

	  result = 1;

	}

    }

  /* turn off realloc slowdown, no longer needed */

  ts.tv_nsec = 0;

  return result;

}

#define TEST_FUNCTION do_test ()

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