Qubes/core-admin
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Use platform specific locking method

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None of found existing portable locking module does support RW locks.
Use lowlevel system locking support - both Windows and Linux support
such feature.

Drop locking code in write_firewall_conf() b/c is is called with
QubesVmCollection lock held anyway.
This commit is contained in:
Marek Marczykowski-Górecki 2013-08-27 04:00:35 +02:00
parent a5a2c0b97c
commit 11047bf427
2 changed files with 20 additions and 6 deletions
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3
core-modules/000QubesVm.py
View File

@ -23,7 +23,6 @@
#
import datetime
import fcntl
import lxml.etree
import os
import os.path
@ -1243,9 +1242,7 @@ class QubesVm(object):
try:
old_umask = os.umask(002)
with open(self.firewall_conf, 'w') as f:
fcntl.lockf(f, fcntl.LOCK_EX)
tree.write(f, encoding="UTF-8", pretty_print=True)
fcntl.lockf(f, fcntl.LOCK_UN)
f.close()
os.umask(old_umask)
except EnvironmentError as err:

23
core/qubes.py
View File

@ -28,12 +28,19 @@ import os
import os.path
import lxml.etree
import xml.parsers.expat
import fcntl
import time
import warnings
import tempfile
import grp
import atexit
if os.name == 'posix':
import fcntl
elif os.name == 'nt':
import win32con
import win32file
import pywintypes
else:
raise RuntimeError, "Qubes works only on POSIX or WinNT systems"
# Do not use XenAPI or create/read any VM files
# This is for testing only!
@ -579,7 +586,12 @@ class QubesVmCollection(dict):
# still the right file
while True:
self.qubes_store_file = open (self.qubes_store_filename, 'r')
fcntl.lockf(self.qubes_store_file, fcntl.LOCK_SH)
if os.name == 'posix':
fcntl.lockf (self.qubes_store_file, fcntl.LOCK_SH)
elif os.name == 'nt':
overlapped = pywintypes.OVERLAPPED()
win32file.LockFileEx(win32file._get_osfhandle(self.qubes_store_file.fileno()),
0, 0, -0x10000, overlapped)
if os.fstat(self.qubes_store_file.fileno()) == os.stat(
self.qubes_store_filename):
break
@ -591,7 +603,12 @@ class QubesVmCollection(dict):
# still the right file
while True:
self.qubes_store_file = open (self.qubes_store_filename, 'r+')
fcntl.lockf(self.qubes_store_file, fcntl.LOCK_EX)
if os.name == 'posix':
fcntl.lockf (self.qubes_store_file, fcntl.LOCK_EX)
elif os.name == 'nt':
overlapped = pywintypes.OVERLAPPED()
win32file.LockFileEx(win32file._get_osfhandle(self.qubes_store_file.fileno()),
win32con.LOCKFILE_EXCLUSIVE_LOCK, 0, -0x10000, overlapped)
if os.fstat(self.qubes_store_file.fileno()) == os.stat(
self.qubes_store_filename):
break