1 files changed, 133 insertions, 0 deletions
diff --git a/nameserv_async.c b/nameserv_async.c
new file mode 100644
index 0000000..9ad3d17
--- /dev/null
+++ b/nameserv_async.c
@@ -0,0 +1,133 @@
+/*
+  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