diff --git a/ChangeLog b/ChangeLog
index 779665edeb..df43aef4ca 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,18 @@
+Mon Jul 31 16:51:40 2006  NAKAMURA Usaku  <usa@ruby-lang.org>
+
+	* win32/win32.c (exit_handler): new function; release winsock and
+	  environment work area.
+
+	* win32/win32.c (NTInitialize): setup exit_handler.
+
+	* win32/win32.c (StartSockets): use exit_handler.
+	  exit handler.
+
+	* win32/win32.c (rb_w32_getenv): use GetEnvironmentStrings() instead
+	  of GetEnvironmentVariable(), because the latter cannot distinguish
+	  wheather a null environment variable exists or not.
+	  fixed: [ruby-talk:205123]
+
 Mon Jul 31 16:15:13 2006  Tanaka Akira  <akr@fsij.org>
 
 	* test/ruby/test_process.rb (TestProcess#test_rlimit_nofile):
diff --git a/win32/win32.c b/win32/win32.c
index 01378ffe2a..348b8bb06e 100644
--- a/win32/win32.c
+++ b/win32/win32.c
@@ -423,6 +423,21 @@ static void invalid_parameter(const wchar_t *expr, const wchar_t *func, const wc
 }
 #endif
 
+static BOOL fWinsock;
+static char *envarea;
+static void
+exit_handler(void)
+{
+    if (fWinsock) {
+	WSACleanup();
+	fWinsock = FALSE;
+    }
+    if (envarea) {
+	FreeEnvironmentStrings(envarea);
+	envarea = NULL;
+    }
+}
+
 //
 // Initialization stuff
 //
@@ -452,6 +467,8 @@ NtInitialize(int *argc, char ***argv)
 
     init_stdhandle();
 
+    atexit(exit_handler);
+
     // Initialize Winsock
     StartSockets();
 
@@ -2207,7 +2224,7 @@ StartSockets(void)
     if (LOBYTE(retdata.wVersion) != 2)
 	rb_fatal("could not find version 2 of winsock dll\n");
 
-    atexit((void (*)(void)) WSACleanup);
+    fWinsock = TRUE;
 
     main_thread.handle = GetCurrentThreadHandle();
     main_thread.id = GetCurrentThreadId();
@@ -3116,28 +3133,22 @@ wait(int *status)
 char *
 rb_w32_getenv(const char *name)
 {
-    static char *curitem = NULL;
-    static DWORD curlen = 0;
-    DWORD needlen;
+    int len = strlen(name);
+    char *env;
 
-    if (curitem == NULL || curlen == 0) {
-	curlen = 512;
-	curitem = ALLOC_N(char, curlen);
-    }
-
-    needlen = GetEnvironmentVariable(name, curitem, curlen);
-    if (needlen != 0) {
-	while (needlen > curlen) {
-	    REALLOC_N(curitem, char, needlen);
-	    curlen = needlen;
-	    needlen = GetEnvironmentVariable(name, curitem, curlen);
-	}
-    }
-    else {
+    if (envarea)
+	FreeEnvironmentStrings(envarea);
+    envarea = GetEnvironmentStrings();
+    if (!envarea) {
+	map_errno(GetLastError());
 	return NULL;
     }
 
-    return curitem;
+    for (env = envarea; *env; env += strlen(env) + 1)
+	if (strncasecmp(env, name, len) == 0 && *(env + len) == '=')
+	    return env + len + 1;
+
+    return NULL;
 }
 
 int