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/* $OpenBSD: res_init.c,v 1.10 2016/04/05 04:29:21 guenther Exp $ */
/*
* Copyright (c) 2012 Eric Faurot <eric@openbsd.org>
*
* Permission to use, copy, modify, and distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/nameser.h>
#include <netinet/in.h>
#include <netdb.h>
#include <asr.h>
#include <resolv.h>
#include <string.h>
#include "asr_private.h"
#include "thread_private.h"
struct __res_state _res;
struct __res_state_ext _res_ext;
int h_errno;
int
res_init(void)
{
static void *resinit_mutex;
struct asr_ctx *ac;
int i;
ac = _asr_use_resolver(NULL);
/*
* The first thread to call res_init() will setup the global _res
* structure from the async context, not overriding fields set early
* by the user.
*/
_MUTEX_LOCK(&resinit_mutex);
if (!(_res.options & RES_INIT)) {
if (_res.retry == 0)
_res.retry = ac->ac_nsretries;
if (_res.options == 0)
_res.options = ac->ac_options;
if (_res.lookups[0] == '\0')
strlcpy(_res.lookups, ac->ac_db, sizeof(_res.lookups));
for (i = 0; i < ac->ac_nscount && i < MAXNS; i++) {
/*
* No need to check for length since we copy to a
* struct sockaddr_storage with a size of 256 bytes
* and sa_len has only 8 bits.
*/
memcpy(&_res_ext.nsaddr_list[i], ac->ac_ns[i],
ac->ac_ns[i]->sa_len);
if (ac->ac_ns[i]->sa_len <= sizeof(_res.nsaddr_list[i]))
memcpy(&_res.nsaddr_list[i], ac->ac_ns[i],
ac->ac_ns[i]->sa_len);
else
memset(&_res.nsaddr_list[i], 0,
sizeof(_res.nsaddr_list[i]));
}
_res.nscount = i;
_res.options |= RES_INIT;
}
_MUTEX_UNLOCK(&resinit_mutex);
/*
* If the program is not threaded, we want to reflect (some) changes
* made by the user to the global _res structure.
* This is a bit of a hack: if there is already an async query on
* this context, it might change things in its back. It is ok
* as long as the user only uses the blocking resolver API.
* If needed we could consider cloning the context if there is
* a running query.
*/
if (!__isthreaded) {
ac->ac_nsretries = _res.retry;
ac->ac_options = _res.options;
strlcpy(ac->ac_db, _res.lookups, sizeof(ac->ac_db));
ac->ac_dbcount = strlen(ac->ac_db);
}
_asr_ctx_unref(ac);
return (0);
}
DEF_WEAK(res_init);
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