build: find out windows platform using GetVersionEx()

ares_gethostbyaddr.c

@@ -186,7 +186,13 @@ static int file_lookup(struct ares_addr *addr, struct hostent **host)
 
 #ifdef WIN32
   char PATH_HOSTS[MAX_PATH];
-  if (IS_NT()) {
+  win_platform platform;
+
+  PATH_HOSTS[0] = '\0';
+
+  platform = getplatform();
+
+  if (platform == WIN_NT) {
     char tmp[MAX_PATH];
     HKEY hkeyHosts;
 
@@ -200,8 +206,10 @@ static int file_lookup(struct ares_addr *addr, struct hostent **host)
       RegCloseKey(hkeyHosts);
     }
   }
-  else
+  else if (platform == WIN_9X)
     GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
+  else
+    return ARES_ENOTFOUND;
 
   strcat(PATH_HOSTS, WIN_PATH_HOSTS);
 

ares_gethostbyname.c

@@ -344,7 +344,13 @@ static int file_lookup(const char *name, int family, struct hostent **host)
 
 #ifdef WIN32
   char PATH_HOSTS[MAX_PATH];
-  if (IS_NT()) {
+  win_platform platform;
+
+  PATH_HOSTS[0] = '\0';
+
+  platform = getplatform();
+
+  if (platform == WIN_NT) {
     char tmp[MAX_PATH];
     HKEY hkeyHosts;
 
@@ -358,8 +364,10 @@ static int file_lookup(const char *name, int family, struct hostent **host)
       RegCloseKey(hkeyHosts);
     }
   }
-  else
+  else if (platform == WIN_9X)
     GetWindowsDirectory(PATH_HOSTS, MAX_PATH);
+  else
+    return ARES_ENOTFOUND;
 
   strcat(PATH_HOSTS, WIN_PATH_HOSTS);
 

ares_init.c

@@ -704,6 +704,7 @@ DhcpNameServer
   DWORD bytes;
   DWORD result;
   char  buf[256];
+  win_platform platform;
 
   if (channel->nservers > -1)  /* don't override ARES_OPT_SERVER */
      return ARES_SUCCESS;
@@ -715,7 +716,9 @@ DhcpNameServer
       goto okay;
   }
 
-  if (IS_NT())
+  platform = getplatform();
+
+  if (platform == WIN_NT)
   {
     if (RegOpenKeyEx(
           HKEY_LOCAL_MACHINE, WIN_NS_NT_KEY, 0,
@@ -749,7 +752,7 @@ DhcpNameServer
       RegCloseKey(mykey);
     }
   }
-  else
+  else if (platform == WIN_9X)
   {
     if (RegOpenKeyEx(
           HKEY_LOCAL_MACHINE, WIN_NS_9X, 0,

ares_private.h

@@ -52,7 +52,6 @@
 
 #if defined(WIN32) && !defined(WATT32)
 
-#define IS_NT()        ((int)GetVersion() > 0)
 #define WIN_NS_9X      "System\\CurrentControlSet\\Services\\VxD\\MSTCP"
 #define WIN_NS_NT_KEY  "System\\CurrentControlSet\\Services\\Tcpip\\Parameters"
 #define NAMESERVER     "NameServer"
@@ -345,6 +344,20 @@ long ares__tvdiff(struct timeval t1, struct timeval t2);
       (c)->sock_state_cb((c)->sock_state_cb_data, (s), (r), (w));       \
   } while (0)
 
+#if (defined(WIN32) || defined(WATT32)) && !defined(MSDOS)
+
+typedef enum {
+  WIN_UNKNOWN,
+  WIN_3X,
+  WIN_9X,
+  WIN_NT,
+  WIN_CE
+} win_platform;
+
+win_platform getplatform(void);
+
+#endif
+
 #ifdef CURLDEBUG
 /* This is low-level hard-hacking memory leak tracking and similar. Using the
    libcurl lowlevel code from within library is ugly and only works when

windows_port.c

@@ -1,5 +1,6 @@
 #include "ares_setup.h"
 
+#include "ares_private.h"
 
 /* only do the following on windows
  */
@@ -19,4 +20,42 @@ WINAPI DllMain (HINSTANCE hnd, DWORD reason, LPVOID reserved)
 }
 #endif
 
+#define V_PLATFORM_WIN32s         0
+#define V_PLATFORM_WIN32_WINDOWS  1
+#define V_PLATFORM_WIN32_NT       2
+#define V_PLATFORM_WIN32_CE       3
+
+win_platform getplatform(void)
+{
+  OSVERSIONINFOEX OsvEx;
+
+  memset(&OsvEx, 0, sizeof(OsvEx));
+  OsvEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
+  if (!GetVersionEx((void *)&OsvEx))
+    {
+      memset(&OsvEx, 0, sizeof(OsvEx));
+      OsvEx.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
+      if (!GetVersionEx((void *)&OsvEx))
+        return WIN_UNKNOWN;
+    }
+
+  switch(OsvEx.dwPlatformId)
+    {
+      case V_PLATFORM_WIN32s:
+        return WIN_3X;
+
+      case V_PLATFORM_WIN32_WINDOWS:
+        return WIN_9X;
+
+      case V_PLATFORM_WIN32_NT:
+        return WIN_NT;
+
+      case V_PLATFORM_WIN32_CE:
+        return WIN_CE;
+
+      default:
+        return WIN_UNKNOWN;
+    }
+}
+
 #endif /* WIN32 builds only */