Issue #9758: When fcntl.ioctl() was called with mutable_flag set to True,

and the passed buffer was exactly 1024 bytes long, the buffer wouldn't
be updated back after the system call.  Original patch by Brian Brazil.
This commit is contained in:
Antoine Pitrou 2010-09-07 16:30:09 +00:00
parent 7f7561ebfc
commit 5e38aae91b
3 changed files with 31 additions and 6 deletions

View File

@ -1,3 +1,4 @@
import array
import unittest
from test.support import run_unittest, import_module, get_attribute
import os, struct
@ -34,16 +35,36 @@ class IoctlTests(unittest.TestCase):
rpgrp = struct.unpack("i", r)[0]
self.assertIn(rpgrp, ids)
def test_ioctl_mutate(self):
import array
buf = array.array('i', [0])
def _check_ioctl_mutate_len(self, nbytes=None):
buf = array.array('i')
intsize = buf.itemsize
ids = (os.getpgrp(), os.getsid(0))
tty = open("/dev/tty", "r")
r = fcntl.ioctl(tty, termios.TIOCGPGRP, buf, 1)
# A fill value unlikely to be in `ids`
fill = -12345
if nbytes is not None:
# Extend the buffer so that it is exactly `nbytes` bytes long
buf.extend([fill] * (nbytes // intsize))
self.assertEqual(len(buf) * intsize, nbytes) # sanity check
else:
buf.append(fill)
with open("/dev/tty", "r") as tty:
r = fcntl.ioctl(tty, termios.TIOCGPGRP, buf, 1)
rpgrp = buf[0]
self.assertEquals(r, 0)
self.assertIn(rpgrp, ids)
def test_ioctl_mutate(self):
self._check_ioctl_mutate_len()
def test_ioctl_mutate_1024(self):
# Issue #9758: a mutable buffer of exactly 1024 bytes wouldn't be
# copied back after the system call.
self._check_ioctl_mutate_len(1024)
def test_ioctl_mutate_2048(self):
# Test with a larger buffer, just for the record.
self._check_ioctl_mutate_len(2048)
def test_ioctl_signed_unsigned_code_param(self):
if not pty:
raise unittest.SkipTest('pty module required')

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@ -13,6 +13,10 @@ Core and Builtins
Library
-------
- Issue #9758: When fcntl.ioctl() was called with mutable_flag set to True,
and the passed buffer was exactly 1024 bytes long, the buffer wouldn't
be updated back after the system call. Original patch by Brian Brazil.
- Updates to the random module:
* Document which parts of the module are guaranteed to stay the same

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@ -157,7 +157,7 @@ fcntl_ioctl(PyObject *self, PyObject *args)
else {
ret = ioctl(fd, code, arg);
}
if (mutate_arg && (len < IOCTL_BUFSZ)) {
if (mutate_arg && (len <= IOCTL_BUFSZ)) {
memcpy(str, buf, len);
}
PyBuffer_Release(&pstr); /* No further access to str below this point */