diff options
| -rw-r--r-- | Doc/library/fcntl.rst | 2 | ||||
| -rwxr-xr-x | Lib/test/test_fcntl.py | 29 | ||||
| -rw-r--r-- | Modules/fcntlmodule.c | 19 |
3 files changed, 44 insertions, 6 deletions
diff --git a/Doc/library/fcntl.rst b/Doc/library/fcntl.rst index 5050a7f..b3b977f 100644 --- a/Doc/library/fcntl.rst +++ b/Doc/library/fcntl.rst @@ -50,6 +50,8 @@ The module defines the following functions: operations are typically defined in the library module :mod:`termios` and the argument handling is even more complicated. + The op parameter is limited to values that can fit in 32-bits. + The parameter *arg* can be one of an integer, absent (treated identically to the integer ``0``), an object supporting the read-only buffer interface (most likely a plain Python string) or an object supporting the read-write buffer interface. 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() diff --git a/Modules/fcntlmodule.c b/Modules/fcntlmodule.c index 1e4a254..96a6cc8 100644 --- a/Modules/fcntlmodule.c +++ b/Modules/fcntlmodule.c @@ -97,11 +97,20 @@ fcntl_ioctl(PyObject *self, PyObject *args) { #define IOCTL_BUFSZ 1024 int fd; - /* In PyArg_ParseTuple below, use the unsigned int 'I' format for - the signed int 'code' variable, because Python turns 0x8000000 - into a large positive number (PyLong, or PyInt on 64-bit - platforms,) whereas C expects it to be a negative int */ - int code; + /* In PyArg_ParseTuple below, we use the unsigned non-checked 'I' + format for the 'code' parameter because Python turns 0x8000000 + into either a large positive number (PyLong or PyInt on 64-bit + platforms) or a negative number on others (32-bit PyInt) + whereas the system expects it to be a 32bit bit field value + regardless of it being passed as an int or unsigned long on + various platforms. See the termios.TIOCSWINSZ constant across + platforms for an example of thise. + + If any of the 64bit platforms ever decide to use more than 32bits + in their unsigned long ioctl codes this will break and need + special casing based on the platform being built on. + */ + unsigned int code; int arg; int ret; char *str; |