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/* BZ #17977 _res_hconf_reorder_addrs test.
Copyright (C) 2015-2021 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
<https://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"
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