From 60a6af74983d45503067b7e53b14117076a05115 Mon Sep 17 00:00:00 2001
From: Yang Tse <yangsita@gmail.com>
Date: Sun, 17 May 2009 17:10:41 +0000
Subject: [PATCH] Introduction of ares_library_init() and
 ares_library_cleanup()

---
 ares/ares_library_init.c | 109 +++++++++++++++++++++++++++++++++++++++
 ares/ares_library_init.h |  24 +++++++++
 2 files changed, 133 insertions(+)
 create mode 100644 ares/ares_library_init.c
 create mode 100644 ares/ares_library_init.h

diff --git a/ares/ares_library_init.c b/ares/ares_library_init.c
new file mode 100644
index 000000000..92bcedf2d
--- /dev/null
+++ b/ares/ares_library_init.c
@@ -0,0 +1,109 @@
+/* $Id$ */
+
+#include "setup.h"
+
+#include "ares.h"
+#include "ares_library_init.h"
+#include "ares_private.h"
+
+/* library-private global and unique instance vars */
+
+#ifdef WIN32
+fpGetNetworkParams_t fpGetNetworkParams = ZERO_NULL;
+fpSystemFunction036_t fpSystemFunction036 = ZERO_NULL;
+#endif
+
+/* library-private global vars with source visibility restricted to this file */
+
+static unsigned int ares_initialized;
+static int          ares_init_flags;
+
+#ifdef WIN32
+static HMODULE hnd_iphlpapi;
+static HMODULE hnd_advapi32;
+#endif
+
+
+static int ares_win32_init(void)
+{
+#ifdef WIN32
+
+  hnd_iphlpapi = 0;
+  hnd_iphlpapi = LoadLibrary("iphlpapi.dll");
+  if (!hnd_iphlpapi)
+    return ARES_ELOADIPHLPAPI;
+
+  fpGetNetworkParams = (fpGetNetworkParams_t)
+    GetProcAddress(hnd_iphlpapi, "GetNetworkParams");
+  if (!fpGetNetworkParams)
+    {
+      FreeLibrary(hnd_iphlpapi);
+      return ARES_EADDRGetNetworkParams;
+    }
+
+  hnd_advapi32 = 0;
+  hnd_advapi32 = LoadLibrary("advapi32.dll");
+  if (!hnd_advapi32)
+    {
+      FreeLibrary(hnd_iphlpapi);
+      return ARES_ELOADADVAPI32;
+    }
+
+  fpSystemFunction036 = (fpSystemFunction036_t)
+    GetProcAddress(hnd_advapi32, "SystemFunction036");
+  if (!fpSystemFunction036)
+    {
+      FreeLibrary(hnd_advapi32);
+      FreeLibrary(hnd_iphlpapi);
+      return ARES_EADDRSYSTEMFUNCTION036;
+    }
+
+#endif
+  return ARES_SUCCESS;
+}
+
+
+static void ares_win32_cleanup(void)
+{
+#ifdef WIN32
+  if (hnd_advapi32)
+    FreeLibrary(hnd_advapi32);
+  if (hnd_iphlpapi)
+    FreeLibrary(hnd_iphlpapi);
+#endif
+}
+
+
+int ares_library_init(int flags)
+{
+  int res;
+
+  if (ares_initialized)
+    return ARES_SUCCESS;
+  ares_initialized++;
+
+  if (flags & ARES_LIB_INIT_WIN32)
+    {
+      res = ares_win32_init();
+      if (res != ARES_SUCCESS)
+        return res;
+    }
+
+  ares_init_flags = flags;
+
+  return ARES_SUCCESS;
+}
+
+
+void ares_library_cleanup(void)
+{
+  if (!ares_initialized)
+    return;
+  ares_initialized--;
+
+  if (ares_init_flags & ARES_LIB_INIT_WIN32)
+    ares_win32_cleanup();
+
+  ares_init_flags = ARES_LIB_INIT_NONE;
+}
+
diff --git a/ares/ares_library_init.h b/ares/ares_library_init.h
new file mode 100644
index 000000000..1b4c760a4
--- /dev/null
+++ b/ares/ares_library_init.h
@@ -0,0 +1,24 @@
+#ifndef HEADER_CARES_LIBRARY_INIT_H
+#define HEADER_CARES_LIBRARY_INIT_H
+
+/* $Id$ */
+
+#include "setup.h"
+
+#ifdef WIN32
+
+#include <iphlpapi.h>
+
+typedef DWORD (WINAPI *fpGetNetworkParams_t) (FIXED_INFO*, DWORD*);
+typedef BOOLEAN (APIENTRY *fpSystemFunction036_t) (void*, ULONG);
+
+/* Forward-declaration of variables defined in ares_library_init.c */
+/* that are global and unique instances for whole c-ares library.  */
+
+extern fpGetNetworkParams_t fpGetNetworkParams;
+extern fpSystemFunction036_t fpSystemFunction036;
+
+#endif /* WIN32 */
+
+#endif /* HEADER_CARES_LIBRARY_INIT_H */
+