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-rw-r--r--nameserv_async.c130
1 files changed, 130 insertions, 0 deletions
diff --git a/nameserv_async.c b/nameserv_async.c
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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 pthread_mutex_t privops_lock = PTHREAD_MUTEX_INITIALIZER;
+
+/* ================================================== */
+
+static void *
+start_resolving(void *anything)
+{
+ struct DNS_Async_Instance *inst = (struct DNS_Async_Instance *)anything;
+
+ pthread_mutex_lock(&privops_lock);
+ inst->status = PRV_Name2IPAddress(inst->name, inst->addresses, DNS_MAX_ADDRESSES);
+ pthread_mutex_unlock(&privops_lock);
+
+ /* 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");
+ }
+
+ 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]);
+
+ 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