Introduction of ares_library_init() and ares_library_cleanup()

1 files changed, 109 insertions, 0 deletions

diff --git a/ares_library_init.c b/ares_library_init.c
new file mode 100644
index 0000000..92bcedf
--- /dev/null
+++ b/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;
+}
+