diff -r e3a773fefddf Lib/test/test_exceptions.py
--- a/Lib/test/test_exceptions.py	Sat Jul 23 15:17:19 2011 +0200
+++ b/Lib/test/test_exceptions.py	Sat Aug 27 08:25:21 2011 -0700
@@ -5,6 +5,7 @@
 import unittest
 import pickle
 import weakref
+import errno
 
 from test.support import (TESTFN, unlink, run_unittest, captured_output,
                           gc_collect, cpython_only, no_tracing)
@@ -790,6 +791,15 @@
             self.fail("RuntimeError not raised")
         self.assertEqual(wr(), None)
 
+    def test_ENOTDIR_errno(self):
+        # os.listdir on file should raise OSError with errno ENOTDIR
+        try:
+            os.listdir(__file__)
+        except OSError as e:
+            self.assertEqual(errno.ENOTDIR, e.errno)
+        else:
+            self.fail("OSError not raised")
+
 def test_main():
     run_unittest(ExceptionTests)
 
diff -r e3a773fefddf PC/errmap.h
--- a/PC/errmap.h	Sat Jul 23 15:17:19 2011 +0200
+++ b/PC/errmap.h	Sat Aug 27 08:25:21 2011 -0700
@@ -1,78 +1,82 @@
-/* Generated file. Do not edit. */
-int winerror_to_errno(int winerror)
-{
-    switch(winerror) {
-        case 2: return 2;
-        case 3: return 2;
-        case 4: return 24;
-        case 5: return 13;
-        case 6: return 9;
-        case 7: return 12;
-        case 8: return 12;
-        case 9: return 12;
-        case 10: return 7;
-        case 11: return 8;
-        case 15: return 2;
-        case 16: return 13;
-        case 17: return 18;
-        case 18: return 2;
-        case 19: return 13;
-        case 20: return 13;
-        case 21: return 13;
-        case 22: return 13;
-        case 23: return 13;
-        case 24: return 13;
-        case 25: return 13;
-        case 26: return 13;
-        case 27: return 13;
-        case 28: return 13;
-        case 29: return 13;
-        case 30: return 13;
-        case 31: return 13;
-        case 32: return 13;
-        case 33: return 13;
-        case 34: return 13;
-        case 35: return 13;
-        case 36: return 13;
-        case 53: return 2;
-        case 65: return 13;
-        case 67: return 2;
-        case 80: return 17;
-        case 82: return 13;
-        case 83: return 13;
-        case 89: return 11;
-        case 108: return 13;
-        case 109: return 32;
-        case 112: return 28;
-        case 114: return 9;
-        case 128: return 10;
-        case 129: return 10;
-        case 130: return 9;
-        case 132: return 13;
-        case 145: return 41;
-        case 158: return 13;
-        case 161: return 2;
-        case 164: return 11;
-        case 167: return 13;
-        case 183: return 17;
-        case 188: return 8;
-        case 189: return 8;
-        case 190: return 8;
-        case 191: return 8;
-        case 192: return 8;
-        case 193: return 8;
-        case 194: return 8;
-        case 195: return 8;
-        case 196: return 8;
-        case 197: return 8;
-        case 198: return 8;
-        case 199: return 8;
-        case 200: return 8;
-        case 201: return 8;
-        case 202: return 8;
-        case 206: return 2;
-        case 215: return 11;
-        case 1816: return 12;
-        default: return EINVAL;
-    }
-}
+/* Generated file. Do not edit. */
+int winerror_to_errno(int winerror)
+{
+	switch(winerror) {
+		case 2: return 2;
+		case 3: return 2;
+		case 4: return 24;
+		case 5: return 13;
+		case 6: return 9;
+		case 7: return 12;
+		case 8: return 12;
+		case 9: return 12;
+		case 10: return 7;
+		case 11: return 8;
+		case 15: return 2;
+		case 16: return 13;
+		case 17: return 18;
+		case 18: return 2;
+		case 19: return 13;
+		case 20: return 13;
+		case 21: return 13;
+		case 22: return 13;
+		case 23: return 13;
+		case 24: return 13;
+		case 25: return 13;
+		case 26: return 13;
+		case 27: return 13;
+		case 28: return 13;
+		case 29: return 13;
+		case 30: return 13;
+		case 31: return 13;
+		case 32: return 13;
+		case 33: return 13;
+		case 34: return 13;
+		case 35: return 13;
+		case 36: return 13;
+		case 53: return 2;
+		case 65: return 13;
+		case 67: return 2;
+		case 80: return 17;
+		case 82: return 13;
+		case 83: return 13;
+		case 89: return 11;
+		case 108: return 13;
+		case 109: return 32;
+		case 112: return 28;
+		case 114: return 9;
+		case 128: return 10;
+		case 129: return 10;
+		case 130: return 9;
+		case 132: return 13;
+		case 145: return 41;
+		case 158: return 13;
+		case 161: return 2;
+		case 164: return 11;
+		case 167: return 13;
+		case 183: return 17;
+		case 188: return 8;
+		case 189: return 8;
+		case 190: return 8;
+		case 191: return 8;
+		case 192: return 8;
+		case 193: return 8;
+		case 194: return 8;
+		case 195: return 8;
+		case 196: return 8;
+		case 197: return 8;
+		case 198: return 8;
+		case 199: return 8;
+		case 200: return 8;
+		case 201: return 8;
+		case 202: return 8;
+		case 206: return 2;
+		case 215: return 11;
+		case 1816: return 12;
+
+		// Additional mappings
+		case 267: return 20;
+
+		default: return EINVAL;
+	}
+}
diff -r e3a773fefddf PC/generrmap.c
--- a/PC/generrmap.c	Sat Jul 23 15:17:19 2011 +0200
+++ b/PC/generrmap.c	Sat Aug 27 08:25:21 2011 -0700
@@ -3,18 +3,42 @@
 
 /* Extract the mapping of Win32 error codes to errno */
 
+/* Additional mappings not returned by _dosmaperr */
+struct error_map {
+    int win_error;
+    int errno_error;
+};
+
+struct error_map extra_errors[] = {
+    { 267, 20 }
+};
+
 int main()
 {
     int i;
     printf("/* Generated file. Do not edit. */\n");
     printf("int winerror_to_errno(int winerror)\n");
     printf("{\n\tswitch(winerror) {\n");
+    
+    /* Add errno mappings returned by _dosmaperr */
     for(i=1; i < 65000; i++) {
         _dosmaperr(i);
         if (errno == EINVAL)
             continue;
         printf("\t\tcase %d: return %d;\n", i, errno);
     }
+    printf("\n");
+
+    /* Add additional mappings */
+    printf("\t\t// Additional mappings\n");
+    for(i=0; i < (sizeof(extra_errors) / sizeof(extra_errors[0])); i++)
+    {
+        printf("\t\tcase %d: return %d;\n", 
+            extra_errors[i].win_error, 
+            extra_errors[i].errno_error);
+    }
+    printf("\n");
+
     printf("\t\tdefault: return EINVAL;\n");
     printf("\t}\n}\n");
 }