5483567190
Run getaddrinfo()/gethostbyname() in separate thread to avoid blocking. Only one resolving thread is running at one time, so this should work also on systems where the functions are not thread-safe.
144 lines
3.4 KiB
C
144 lines
3.4 KiB
C
/*
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chronyd/chronyc - Programs for keeping computer clocks accurate.
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**********************************************************************
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* Copyright (C) Miroslav Lichvar 2014
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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**********************************************************************
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=======================================================================
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Functions to asynchronously convert name to IP address
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*/
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#include "config.h"
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#include "sysincl.h"
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#include "nameserv_async.h"
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#include "logging.h"
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#include "memory.h"
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#include "sched.h"
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#include "util.h"
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#ifdef FEAT_ASYNCDNS
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#ifdef USE_PTHREAD_ASYNCDNS
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#include <pthread.h>
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/* ================================================== */
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struct DNS_Async_Instance {
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const char *name;
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DNS_Status status;
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IPAddr addr;
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DNS_NameResolveHandler handler;
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void *arg;
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pthread_t thread;
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int pipe[2];
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};
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static int resolving_threads = 0;
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/* ================================================== */
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static void *
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start_resolving(void *anything)
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{
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struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
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inst->status = DNS_Name2IPAddress(inst->name, &inst->addr);
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/* Notify the main thread that the result is ready */
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if (write(inst->pipe[1], "", 1) < 0)
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;
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return NULL;
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}
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/* ================================================== */
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static void
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end_resolving(void *anything)
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{
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struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
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if (pthread_join(inst->thread, NULL)) {
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LOG_FATAL(LOGF_Nameserv, "pthread_join() failed");
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}
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resolving_threads--;
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SCH_RemoveInputFileHandler(inst->pipe[0]);
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close(inst->pipe[0]);
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close(inst->pipe[1]);
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(inst->handler)(inst->status, &inst->addr, inst->arg);
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Free(inst);
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}
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/* ================================================== */
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void
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DNS_Name2IPAddressAsync(const char *name, DNS_NameResolveHandler handler, void *anything)
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{
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struct DNS_Async_Instance *inst;
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inst = MallocNew(struct DNS_Async_Instance);
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inst->name = name;
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inst->handler = handler;
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inst->arg = anything;
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inst->status = DNS_Failure;
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if (pipe(inst->pipe)) {
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LOG_FATAL(LOGF_Nameserv, "pipe() failed");
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}
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resolving_threads++;
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assert(resolving_threads <= 1);
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if (pthread_create(&inst->thread, NULL, start_resolving, inst)) {
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LOG_FATAL(LOGF_Nameserv, "pthread_create() failed");
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}
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SCH_AddInputFileHandler(inst->pipe[0], end_resolving, inst);
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}
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/* ================================================== */
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#else
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#error
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#endif
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#else
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/* This is a blocking implementation used when nothing else is available */
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void
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DNS_Name2IPAddressAsync(const char *name, DNS_NameResolveHandler handler, void *anything)
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{
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IPAddr addr;
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DNS_Status status;
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status = DNS_Name2IPAddress(name, &addr);
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(handler)(status, &addr, anything);
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}
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/* ================================================== */
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#endif
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