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/*
chronyd/chronyc - Programs for keeping computer clocks accurate.
**********************************************************************
* Copyright (C) Miroslav Lichvar 2014
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of version 2 of the GNU General Public License as
* published by the Free Software Foundation.
*
* 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, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
**********************************************************************
=======================================================================
Functions to asynchronously convert name to IP address
*/
#include "config.h"
#include "sysincl.h"
#include "nameserv_async.h"
#include "logging.h"
#include "memory.h"
#include "privops.h"
#include "sched.h"
#include "util.h"
#ifdef USE_PTHREAD_ASYNCDNS
#include <pthread.h>
/* ================================================== */
struct DNS_Async_Instance {
const char *name;
DNS_Status status;
IPAddr addresses[DNS_MAX_ADDRESSES];
DNS_NameResolveHandler handler;
void *arg;
pthread_t thread;
int pipe[2];
};
static int resolving_threads = 0;
/* ================================================== */
static void *
start_resolving(void *anything)
{
struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
inst->status = PRV_Name2IPAddress(inst->name, inst->addresses, DNS_MAX_ADDRESSES);
/* Notify the main thread that the result is ready */
if (write(inst->pipe[1], "", 1) < 0)
;
return NULL;
}
/* ================================================== */
static void
end_resolving(int fd, int event, void *anything)
{
struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
int i;
if (pthread_join(inst->thread, NULL)) {
LOG_FATAL("pthread_join() failed");
}
resolving_threads--;
SCH_RemoveFileHandler(inst->pipe[0]);
close(inst->pipe[0]);
close(inst->pipe[1]);
for (i = 0; inst->status == DNS_Success && i < DNS_MAX_ADDRESSES &&
inst->addresses[i].family != IPADDR_UNSPEC; i++)
;
(inst->handler)(inst->status, i, inst->addresses, inst->arg);
Free(inst);
}
/* ================================================== */
void
DNS_Name2IPAddressAsync(const char *name, DNS_NameResolveHandler handler, void *anything)
{
struct DNS_Async_Instance *inst;
inst = MallocNew(struct DNS_Async_Instance);
inst->name = name;
inst->handler = handler;
inst->arg = anything;
inst->status = DNS_Failure;
if (pipe(inst->pipe)) {
LOG_FATAL("pipe() failed");
}
UTI_FdSetCloexec(inst->pipe[0]);
UTI_FdSetCloexec(inst->pipe[1]);
resolving_threads++;
assert(resolving_threads <= 1);
if (pthread_create(&inst->thread, NULL, start_resolving, inst)) {
LOG_FATAL("pthread_create() failed");
}
SCH_AddFileHandler(inst->pipe[0], SCH_FILE_INPUT, end_resolving, inst);
}
/* ================================================== */
#else
#error
#endif
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