commit 03b9b99beaa55f38bac1ccb13c3b0c19ac461014
Author: Peter Weldon <peter.weldon@null.net>
Date:   Tue Sep 7 15:51:53 2010 -0700

    hash.c (ruby_setenv): Add error checking for win32

diff --git a/hash.c b/hash.c
index 8bba586..77301e4 100644
--- a/hash.c
+++ b/hash.c
@@ -2141,27 +2141,19 @@ ruby_setenv(const char *name, const char *value)
 #if defined(_WIN32)
     int len;
     char *buf;
-    if (strchr(name, '=')) {
-	errno = EINVAL;
-	rb_sys_fail("ruby_setenv");
-    }
-    if (value) {
-	len = strlen(name) + 1 + strlen(value) + 1;
-	buf = ALLOCA_N(char, len);
-	snprintf(buf, len, "%s=%s", name, value);
-	putenv(buf);
-
-	/* putenv() doesn't handle empty value */
-	if (!*value)
-	    SetEnvironmentVariable(name,value);
-    }
-    else {
-	len = strlen(name) + 1 + 1;
-	buf = ALLOCA_N(char, len);
-	snprintf(buf, len, "%s=", name);
-	putenv(buf);
-	SetEnvironmentVariable(name, 0);
-    }
+    const char *new_value = value ? value : "";
+    if (strchr(name, '=')) goto fail;
+    len = strlen(name) + 1 + strlen(new_value) + 1;
+    buf = ALLOCA_N(char, len);
+    if (!buf) goto fail;
+    snprintf(buf, len, "%s=%s", name, new_value);
+    if (putenv(buf)) goto fail;
+    if ((!value || !*value) && !SetEnvironmentVariable(name,value)) 
+      goto fail;
+    return;
+ fail:
+    errno = EINVAL;
+    rb_sys_fail("ruby_setenv");
 #elif defined(HAVE_SETENV) && defined(HAVE_UNSETENV)
 #undef setenv
 #undef unsetenv
diff --git a/test/ruby/test_env.rb b/test/ruby/test_env.rb
index 785b6bb..52b95e3 100644
--- a/test/ruby/test_env.rb
+++ b/test/ruby/test_env.rb
@@ -1,4 +1,5 @@
 require 'test/unit'
+require 'rbconfig'
 
 class TestEnv < Test::Unit::TestCase
   IGNORE_CASE = /bccwin|mswin|mingw/ =~ RUBY_PLATFORM
@@ -374,4 +375,16 @@ class TestEnv < Test::Unit::TestCase
     ENV.update({"baz"=>"quux","a"=>"b"}) {|k, v1, v2| v1 ? k + "_" + v1 + "_" + v2 : v2 }
     check(ENV.to_hash.to_a, [%w(foo bar), %w(baz baz_qux_quux), %w(a b)])
   end
+
+  def test_huge_value
+    huge_value = "bar" * 40960
+    ENV["foo"] = "bar"
+    if Config::CONFIG['host_os'] =~ /mswin|mingw/
+      assert_raise(Errno::EINVAL) { ENV["foo"] = huge_value }
+      assert_equal("bar", ENV["foo"])
+    else
+      assert_nothing_raised { ENV["foo"] = huge_value }
+      assert_equal(huge_value, ENV["foo"])
+    end
+  end
 end