273 lines
8.8 KiB
Python
273 lines
8.8 KiB
Python
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# Copyright 2011-2015, Damian Johnson and The Tor Project
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# See LICENSE for licensing information
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"""
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Helper functions for working with tor as a process.
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:NO_TORRC:
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when provided as a torrc_path tor is ran with a blank configuration
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:DEFAULT_INIT_TIMEOUT:
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number of seconds before we time out our attempt to start a tor instance
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**Module Overview:**
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::
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launch_tor - starts up a tor process
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launch_tor_with_config - starts a tor process with a custom torrc
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"""
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import os
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import re
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import signal
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import subprocess
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import tempfile
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import stem.prereq
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import stem.util.str_tools
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import stem.util.system
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import stem.version
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NO_TORRC = '<no torrc>'
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DEFAULT_INIT_TIMEOUT = 90
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def launch_tor(tor_cmd = 'tor', args = None, torrc_path = None, completion_percent = 100, init_msg_handler = None, timeout = DEFAULT_INIT_TIMEOUT, take_ownership = False, stdin = None):
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"""
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Initializes a tor process. This blocks until initialization completes or we
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error out.
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If tor's data directory is missing or stale then bootstrapping will include
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making several requests to the directory authorities which can take a little
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while. Usually this is done in 50 seconds or so, but occasionally calls seem
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to get stuck, taking well over the default timeout.
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**To work to must log at NOTICE runlevel to stdout.** It does this by
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default, but if you have a 'Log' entry in your torrc then you'll also need
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'Log NOTICE stdout'.
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Note: The timeout argument does not work on Windows, and relies on the global
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state of the signal module.
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:param str tor_cmd: command for starting tor
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:param list args: additional arguments for tor
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:param str torrc_path: location of the torrc for us to use
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:param int completion_percent: percent of bootstrap completion at which
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this'll return
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:param functor init_msg_handler: optional functor that will be provided with
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tor's initialization stdout as we get it
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:param int timeout: time after which the attempt to start tor is aborted, no
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timeouts are applied if **None**
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:param bool take_ownership: asserts ownership over the tor process so it
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aborts if this python process terminates or a :class:`~stem.control.Controller`
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we establish to it disconnects
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:param str stdin: content to provide on stdin
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:returns: **subprocess.Popen** instance for the tor subprocess
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:raises: **OSError** if we either fail to create the tor process or reached a
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timeout without success
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"""
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if stem.util.system.is_windows():
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timeout = None
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# sanity check that we got a tor binary
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if os.path.sep in tor_cmd:
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# got a path (either relative or absolute), check what it leads to
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if os.path.isdir(tor_cmd):
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raise OSError("'%s' is a directory, not the tor executable" % tor_cmd)
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elif not os.path.isfile(tor_cmd):
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raise OSError("'%s' doesn't exist" % tor_cmd)
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elif not stem.util.system.is_available(tor_cmd):
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raise OSError("'%s' isn't available on your system. Maybe it's not in your PATH?" % tor_cmd)
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# double check that we have a torrc to work with
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if torrc_path not in (None, NO_TORRC) and not os.path.exists(torrc_path):
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raise OSError("torrc doesn't exist (%s)" % torrc_path)
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# starts a tor subprocess, raising an OSError if it fails
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runtime_args, temp_file = [tor_cmd], None
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if args:
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runtime_args += args
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if torrc_path:
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if torrc_path == NO_TORRC:
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temp_file = tempfile.mkstemp(prefix = 'empty-torrc-', text = True)[1]
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runtime_args += ['-f', temp_file]
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else:
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runtime_args += ['-f', torrc_path]
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if take_ownership:
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runtime_args += ['__OwningControllerProcess', str(os.getpid())]
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tor_process = subprocess.Popen(runtime_args, stdout = subprocess.PIPE, stdin = subprocess.PIPE, stderr = subprocess.PIPE)
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if stdin:
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tor_process.stdin.write(stem.util.str_tools._to_bytes(stdin))
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tor_process.stdin.close()
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if timeout:
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def timeout_handler(signum, frame):
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# terminates the uninitialized tor process and raise on timeout
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tor_process.kill()
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raise OSError('reached a %i second timeout without success' % timeout)
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signal.signal(signal.SIGALRM, timeout_handler)
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signal.alarm(timeout)
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bootstrap_line = re.compile('Bootstrapped ([0-9]+)%: ')
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problem_line = re.compile('\[(warn|err)\] (.*)$')
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last_problem = 'Timed out'
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try:
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while True:
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# Tor's stdout will be read as ASCII bytes. This is fine for python 2, but
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# in python 3 that means it'll mismatch with other operations (for instance
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# the bootstrap_line.search() call later will fail).
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#
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# It seems like python 2.x is perfectly happy for this to be unicode, so
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# normalizing to that.
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init_line = tor_process.stdout.readline().decode('utf-8', 'replace').strip()
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# this will provide empty results if the process is terminated
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if not init_line:
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tor_process.kill() # ... but best make sure
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raise OSError('Process terminated: %s' % last_problem)
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# provide the caller with the initialization message if they want it
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if init_msg_handler:
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init_msg_handler(init_line)
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# return the process if we're done with bootstrapping
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bootstrap_match = bootstrap_line.search(init_line)
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problem_match = problem_line.search(init_line)
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if bootstrap_match and int(bootstrap_match.group(1)) >= completion_percent:
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return tor_process
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elif problem_match:
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runlevel, msg = problem_match.groups()
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if 'see warnings above' not in msg:
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if ': ' in msg:
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msg = msg.split(': ')[-1].strip()
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last_problem = msg
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finally:
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if timeout:
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signal.alarm(0) # stop alarm
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tor_process.stdout.close()
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tor_process.stderr.close()
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if temp_file:
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try:
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os.remove(temp_file)
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except:
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pass
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def launch_tor_with_config(config, tor_cmd = 'tor', completion_percent = 100, init_msg_handler = None, timeout = DEFAULT_INIT_TIMEOUT, take_ownership = False):
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"""
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Initializes a tor process, like :func:`~stem.process.launch_tor`, but with a
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customized configuration. This writes a temporary torrc to disk, launches
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tor, then deletes the torrc.
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For example...
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::
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tor_process = stem.process.launch_tor_with_config(
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config = {
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'ControlPort': '2778',
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'Log': [
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'NOTICE stdout',
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'ERR file /tmp/tor_error_log',
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],
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},
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)
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:param dict config: configuration options, such as "{'ControlPort': '9051'}",
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values can either be a **str** or **list of str** if for multiple values
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:param str tor_cmd: command for starting tor
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:param int completion_percent: percent of bootstrap completion at which
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this'll return
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:param functor init_msg_handler: optional functor that will be provided with
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tor's initialization stdout as we get it
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:param int timeout: time after which the attempt to start tor is aborted, no
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timeouts are applied if **None**
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:param bool take_ownership: asserts ownership over the tor process so it
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aborts if this python process terminates or a :class:`~stem.control.Controller`
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we establish to it disconnects
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:returns: **subprocess.Popen** instance for the tor subprocess
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:raises: **OSError** if we either fail to create the tor process or reached a
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timeout without success
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"""
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# TODO: Drop this version check when tor 0.2.6.3 or higher is the only game
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# in town.
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try:
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use_stdin = stem.version.get_system_tor_version(tor_cmd) >= stem.version.Requirement.TORRC_VIA_STDIN
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except IOError:
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use_stdin = False
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# we need to be sure that we're logging to stdout to figure out when we're
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# done bootstrapping
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if 'Log' in config:
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stdout_options = ['DEBUG stdout', 'INFO stdout', 'NOTICE stdout']
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if isinstance(config['Log'], str):
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config['Log'] = [config['Log']]
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has_stdout = False
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for log_config in config['Log']:
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if log_config in stdout_options:
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has_stdout = True
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break
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if not has_stdout:
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config['Log'].append('NOTICE stdout')
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config_str = ''
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for key, values in list(config.items()):
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if isinstance(values, str):
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config_str += '%s %s\n' % (key, values)
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else:
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for value in values:
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config_str += '%s %s\n' % (key, value)
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if use_stdin:
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return launch_tor(tor_cmd, ['-f', '-'], None, completion_percent, init_msg_handler, timeout, take_ownership, stdin = config_str)
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else:
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torrc_descriptor, torrc_path = tempfile.mkstemp(prefix = 'torrc-', text = True)
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try:
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with open(torrc_path, 'w') as torrc_file:
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torrc_file.write(config_str)
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# prevents tor from erroring out due to a missing torrc if it gets a sighup
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args = ['__ReloadTorrcOnSIGHUP', '0']
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return launch_tor(tor_cmd, args, torrc_path, completion_percent, init_msg_handler, timeout, take_ownership)
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finally:
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try:
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os.close(torrc_descriptor)
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os.remove(torrc_path)
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except:
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pass
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