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# copyright 2003-2011 LOGILAB S.A. (Paris, FRANCE), all rights reserved.
# contact --
# This file is part of logilab-common.
# logilab-common is free software: you can redistribute it and/or modify it under
# the terms of the GNU Lesser General Public License as published by the Free
# Software Foundation, either version 2.1 of the License, or (at your option) any
# later version.
# logilab-common is distributed in the hope that it will be useful, but WITHOUT
# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
# FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more
# details.
# You should have received a copy of the GNU Lesser General Public License along
# with logilab-common. If not, see <>.
"""A daemonize function (for Unices)"""
__docformat__ = "restructuredtext en"
import os
import errno
import signal
import sys
import time
import warnings
from six.moves import range
def setugid(user):
"""Change process user and group ID
Argument is a numeric user id or a user name"""
from pwd import getpwuid
passwd = getpwuid(int(user))
except ValueError:
from pwd import getpwnam
passwd = getpwnam(user)
if hasattr(os, 'initgroups'): # python >= 2.7
os.initgroups(passwd.pw_name, passwd.pw_gid)
import ctypes
if ctypes.CDLL(None).initgroups(passwd.pw_name, passwd.pw_gid) < 0:
err = ctypes.c_int.in_dll(ctypes.pythonapi,"errno").value
raise OSError(err, os.strerror(err), 'initgroups')
os.environ['HOME'] = passwd.pw_dir
def daemonize(pidfile=None, uid=None, umask=0o77):
"""daemonize a Unix process. Set paranoid umask by default.
Return 1 in the original process, 2 in the first fork, and None for the
second fork (eg daemon process).
# fork so the parent can exit
if os.fork(): # launch child and...
return 1
# disconnect from tty and create a new session
# fork again so the parent, (the session group leader), can exit.
# as a non-session group leader, we can never regain a controlling
# terminal.
if os.fork(): # launch child again.
return 2
# move to the root to avoit mount pb
# redirect standard descriptors
null ='/dev/null', os.O_RDWR)
for i in range(3):
os.dup2(null, i)
except OSError as e:
if e.errno != errno.EBADF:
# filter warnings
# write pid in a file
if pidfile:
# ensure the directory where the pid-file should be set exists (for
# instance /var/run/cubicweb may be deleted on computer restart)
piddir = os.path.dirname(pidfile)
if not os.path.exists(piddir):
f = file(pidfile, 'w')
# set umask if specified
if umask is not None:
# change process uid
if uid:
return None