Prevent ioctl op codes from being sign extended from int to unsigned long

when used on platforms that actually define ioctl as taking an unsigned long.
(the BSDs and OS X / Darwin)

Adds a unittest for fcntl.ioctl that tests what happens with both positive and
negative numbers.

This was done because of issue1471 but I'm not able to reproduce -that- problem
in the first place on Linux 32bit or 64bit or OS X 10.4 & 10.5 32bit or 64 bit.

1 files changed, 28 insertions, 1 deletions

diff --git a/Lib/test/test_fcntl.py b/Lib/test/test_fcntl.py
index feed870..08b59ec 100755
--- a/Lib/test/test_fcntl.py
+++ b/Lib/test/test_fcntl.py
@@ -5,12 +5,18 @@ OS/2+EMX doesn't support the file locking operations.
 """
 import struct
 import fcntl
-import os, sys
+import os
+import struct
+import sys
 import unittest
 from test.test_support import verbose, TESTFN, unlink, run_unittest
 
 # TODO - Write tests for ioctl(), flock() and lockf().
 
+try:
+    import termios
+except ImportError:
+    termios = None
 
 def get_lockdata():
     if sys.platform.startswith('atheos'):
@@ -82,8 +88,29 @@ class TestFcntl(unittest.TestCase):
         self.f.close()
 
 
+class TestIoctl(unittest.TestCase):
+    if termios:
+        def test_ioctl_signed_unsigned_code_param(self):
+            if termios.TIOCSWINSZ < 0:
+                set_winsz_opcode_maybe_neg = termios.TIOCSWINSZ
+                set_winsz_opcode_pos = termios.TIOCSWINSZ & 0xffffffffL
+            else:
+                set_winsz_opcode_pos = termios.TIOCSWINSZ
+                set_winsz_opcode_maybe_neg, = struct.unpack("i",
+                        struct.pack("I", termios.TIOCSWINSZ))
+
+            # We're just testing that these calls do not raise exceptions.
+            saved_winsz = fcntl.ioctl(0, termios.TIOCGWINSZ, "\0"*8)
+            our_winsz = struct.pack("HHHH",80,25,0,0)
+            # test both with a positive and potentially negative ioctl code
+            new_winsz = fcntl.ioctl(0, set_winsz_opcode_pos, our_winsz)
+            new_winsz = fcntl.ioctl(0, set_winsz_opcode_maybe_neg, our_winsz)
+            fcntl.ioctl(0, set_winsz_opcode_maybe_neg, saved_winsz)
+
+
 def test_main():
     run_unittest(TestFcntl)
+    run_unittest(TestIoctl)
 
 if __name__ == '__main__':
     test_main()