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#!/usr/bin/python
# -*- coding: utf-8 -*-
#
# Copyright 2014-2015 clowwindy
#
# Licensed under the Apache License, Version 2.0 (the "License"); you may
# not use this file except in compliance with the License. You may obtain
# a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
# License for the specific language governing permissions and limitations
# under the License.
from __future__ import absolute_import, division, print_function, \
with_statement
import os
import sys
import logging
import signal
import time
from shadowsocks import common, shell
# this module is ported from ShadowVPN daemon.c
def daemon_exec(config):
if 'daemon' in config:
if os.name != 'posix':
raise Exception('daemon mode is only supported on Unix')
command = config['daemon']
if not command:
command = 'start'
pid_file = config['pid-file']
log_file = config['log-file']
if command == 'start':
daemon_start(pid_file, log_file)
elif command == 'stop':
daemon_stop(pid_file)
# always exit after daemon_stop
sys.exit(0)
elif command == 'restart':
daemon_stop(pid_file)
daemon_start(pid_file, log_file)
else:
raise Exception('unsupported daemon command %s' % command)
def write_pid_file(pid_file, pid):
import fcntl
import stat
try:
fd = os.open(pid_file, os.O_RDWR | os.O_CREAT,
stat.S_IRUSR | stat.S_IWUSR)
except OSError as e:
shell.print_exception(e)
return -1
flags = fcntl.fcntl(fd, fcntl.F_GETFD)
assert flags != -1
flags |= fcntl.FD_CLOEXEC
r = fcntl.fcntl(fd, fcntl.F_SETFD, flags)
assert r != -1
# There is no platform independent way to implement fcntl(fd, F_SETLK, &fl)
# via fcntl.fcntl. So use lockf instead
try:
fcntl.lockf(fd, fcntl.LOCK_EX | fcntl.LOCK_NB, 0, 0, os.SEEK_SET)
except IOError:
r = os.read(fd, 32)
if r:
logging.error('already started at pid %s' % common.to_str(r))
else:
logging.error('already started')
os.close(fd)
return -1
os.ftruncate(fd, 0)
os.write(fd, common.to_bytes(str(pid)))
return 0
def freopen(f, mode, stream):
oldf = open(f, mode)
oldfd = oldf.fileno()
newfd = stream.fileno()
os.close(newfd)
os.dup2(oldfd, newfd)
def daemon_start(pid_file, log_file):
def handle_exit(signum, _):
if signum == signal.SIGTERM:
sys.exit(0)
sys.exit(1)
signal.signal(signal.SIGINT, handle_exit)
signal.signal(signal.SIGTERM, handle_exit)
# fork only once because we are sure parent will exit
pid = os.fork()
assert pid != -1
if pid > 0:
# parent waits for its child
time.sleep(5)
sys.exit(0)
# child signals its parent to exit
ppid = os.getppid()
pid = os.getpid()
if write_pid_file(pid_file, pid) != 0:
os.kill(ppid, signal.SIGINT)
sys.exit(1)
os.setsid()
signal.signal(signal.SIG_IGN, signal.SIGHUP)
print('started')
os.kill(ppid, signal.SIGTERM)
sys.stdin.close()
try:
freopen(log_file, 'a', sys.stdout)
freopen(log_file, 'a', sys.stderr)
except IOError as e:
shell.print_exception(e)
sys.exit(1)
def daemon_stop(pid_file):
import errno
try:
with open(pid_file) as f:
buf = f.read()
pid = common.to_str(buf)
if not buf:
logging.error('not running')
except IOError as e:
shell.print_exception(e)
if e.errno == errno.ENOENT:
# always exit 0 if we are sure daemon is not running
logging.error('not running')
return
sys.exit(1)
pid = int(pid)
if pid > 0:
try:
os.kill(pid, signal.SIGTERM)
except OSError as e:
if e.errno == errno.ESRCH:
logging.error('not running')
# always exit 0 if we are sure daemon is not running
return
shell.print_exception(e)
sys.exit(1)
else:
logging.error('pid is not positive: %d', pid)
# sleep for maximum 10s
for i in range(0, 200):
try:
# query for the pid
os.kill(pid, 0)
except OSError as e:
if e.errno == errno.ESRCH:
break
time.sleep(0.05)
else:
logging.error('timed out when stopping pid %d', pid)
sys.exit(1)
print('stopped')
os.unlink(pid_file)
def set_user(username):
if username is None:
return
import pwd
import grp
try:
pwrec = pwd.getpwnam(username)
except KeyError:
logging.error('user not found: %s' % username)
raise
user = pwrec[0]
uid = pwrec[2]
gid = pwrec[3]
cur_uid = os.getuid()
if uid == cur_uid:
return
if cur_uid != 0:
logging.error('can not set user as nonroot user')
# will raise later
# inspired by supervisor
if hasattr(os, 'setgroups'):
groups = [grprec[2] for grprec in grp.getgrall() if user in grprec[3]]
groups.insert(0, gid)
os.setgroups(groups)
os.setgid(gid)
os.setuid(uid)
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