compileall used the ctime of bytecode and source to determine if the bytecode

should be recreated. This created a timing hole. Fixed by just doing what
import does; check the mtime and magic number.
This commit is contained in:
Brett Cannon 2009-02-10 02:07:38 +00:00
parent 322daea7c3
commit 28d108893c
4 changed files with 84 additions and 8 deletions

View File

@ -11,10 +11,11 @@ packages -- for now, you'll have to deal with packages separately.)
See module py_compile for details of the actual byte-compilation.
"""
import os
import sys
import py_compile
import struct
import imp
__all__ = ["compile_dir","compile_path"]
@ -54,11 +55,17 @@ def compile_dir(dir, maxlevels=10, ddir=None,
if os.path.isfile(fullname):
head, tail = name[:-3], name[-3:]
if tail == '.py':
cfile = fullname + (__debug__ and 'c' or 'o')
ftime = os.stat(fullname).st_mtime
try: ctime = os.stat(cfile).st_mtime
except os.error: ctime = 0
if (ctime > ftime) and not force: continue
if not force:
try:
mtime = os.stat(fullname).st_mtime
expect = struct.pack('<4sl', imp.get_magic(), mtime)
cfile = fullname + (__debug__ and 'c' or 'o')
with open(cfile, 'rb') as chandle:
actual = chandle.read(8)
if expect == actual:
continue
except IOError:
pass
if not quiet:
print 'Compiling', fullname, '...'
try:
@ -80,7 +87,8 @@ def compile_dir(dir, maxlevels=10, ddir=None,
name != os.curdir and name != os.pardir and \
os.path.isdir(fullname) and \
not os.path.islink(fullname):
if not compile_dir(fullname, maxlevels - 1, dfile, force, rx, quiet):
if not compile_dir(fullname, maxlevels - 1, dfile, force, rx,
quiet):
success = 0
return success

View File

@ -0,0 +1,63 @@
import compileall
import imp
import os
import py_compile
import shutil
import struct
import sys
import tempfile
import time
from test import test_support
import unittest
class CompileallTests(unittest.TestCase):
def setUp(self):
self.directory = tempfile.mkdtemp()
self.source_path = os.path.join(self.directory, '_test.py')
self.bc_path = self.source_path + ('c' if __debug__ else 'o')
with open(self.source_path, 'w') as file:
file.write('x = 123\n')
def tearDown(self):
shutil.rmtree(self.directory)
def data(self):
with open(self.bc_path, 'rb') as file:
data = file.read(8)
mtime = int(os.stat(self.source_path).st_mtime)
compare = struct.pack('<4sl', imp.get_magic(), mtime)
return data, compare
def recreation_check(self, metadata):
"""Check that compileall recreates bytecode when the new metadata is
used."""
if not hasattr(os, 'stat'):
return
py_compile.compile(self.source_path)
self.assertEqual(*self.data())
with open(self.bc_path, 'rb') as file:
bc = file.read()[len(metadata):]
with open(self.bc_path, 'wb') as file:
file.write(metadata)
file.write(bc)
self.assertNotEqual(*self.data())
compileall.compile_dir(self.directory, force=False, quiet=True)
self.assertTrue(*self.data())
def test_mtime(self):
# Test a change in mtime leads to a new .pyc.
self.recreation_check(struct.pack('<4sl', imp.get_magic(), 1))
def test_magic_number(self):
# Test a change in mtime leads to a new .pyc.
self.recreation_check(b'\0\0\0\0')
def test_main():
test_support.run_unittest(CompileallTests)
if __name__ == "__main__":
test_main()

View File

@ -183,7 +183,7 @@ Virgil Dupras
Andy Dustman
Gary Duzan
Eugene Dvurechenski
Josip Dzolonga
Josip Dzolonga
Maxim Dzumanenko
Walter Dörwald
Hans Eckardt
@ -233,6 +233,7 @@ Peter Funk
Geoff Furnish
Ulisses Furquim
Achim Gaedke
Martin von Gagern
Lele Gaifax
Santiago Gala
Yitzchak Gale

View File

@ -152,6 +152,10 @@ Core and Builtins
Library
-------
- Issue #5128: Make compileall properly inspect bytecode to determine if needs
to be recreated. This avoids a timing hole thanks to the old reliance on the
ctime of the files involved.
- Issue #5122: Synchronize tk load failure check to prevent a potential
deadlock.