1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250
|
# Copyright 2019, David Wilson
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions are met:
#
# 1. Redistributions of source code must retain the above copyright notice,
# this list of conditions and the following disclaimer.
#
# 2. Redistributions in binary form must reproduce the above copyright notice,
# this list of conditions and the following disclaimer in the documentation
# and/or other materials provided with the distribution.
#
# 3. Neither the name of the copyright holder nor the names of its contributors
# may be used to endorse or promote products derived from this software without
# specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
# AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
# IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
# ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
# LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
# CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
# SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
# INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
# CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
# ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
# POSSIBILITY OF SUCH DAMAGE.
# !mitogen: minify_safe
import errno
import logging
import os
import random
import sys
import threading
import traceback
import mitogen.core
import mitogen.parent
from mitogen.core import b
LOG = logging.getLogger(__name__)
# Python 2.4/2.5 cannot support fork+threads whatsoever, it doesn't even fix up
# interpreter state. So 2.4/2.5 interpreters start .local() contexts for
# isolation instead. Since we don't have any crazy memory sharing problems to
# avoid, there is no virginal fork parent either. The child is started directly
# from the login/become process. In future this will be default everywhere,
# fork is brainwrong from the stone age.
FORK_SUPPORTED = sys.version_info >= (2, 6)
class Error(mitogen.core.StreamError):
pass
def fixup_prngs():
"""
Add 256 bits of /dev/urandom to OpenSSL's PRNG in the child, and re-seed
the random package with the same data.
"""
s = os.urandom(256 // 8)
random.seed(s)
if 'ssl' in sys.modules:
sys.modules['ssl'].RAND_add(s, 75.0)
def reset_logging_framework():
"""
After fork, ensure any logging.Handler locks are recreated, as a variety of
threads in the parent may have been using the logging package at the moment
of fork.
It is not possible to solve this problem in general; see :gh:issue:`150`
for a full discussion.
"""
logging._lock = threading.RLock()
# The root logger does not appear in the loggerDict.
logging.Logger.manager.loggerDict = {}
logging.getLogger().handlers = []
def on_fork():
"""
Should be called by any program integrating Mitogen each time the process
is forked, in the context of the new child.
"""
reset_logging_framework() # Must be first!
fixup_prngs()
mitogen.core.Latch._on_fork()
mitogen.core.Side._on_fork()
mitogen.core.ExternalContext.service_stub_lock = threading.Lock()
mitogen__service = sys.modules.get('mitogen.service')
if mitogen__service:
mitogen__service._pool_lock = threading.Lock()
def handle_child_crash():
"""
Respond to _child_main() crashing by ensuring the relevant exception is
logged to /dev/tty.
"""
tty = open('/dev/tty', 'wb')
tty.write('\n\nFORKED CHILD PID %d CRASHED\n%s\n\n' % (
os.getpid(),
traceback.format_exc(),
))
tty.close()
os._exit(1)
def _convert_exit_status(status):
"""
Convert a :func:`os.waitpid`-style exit status to a :mod:`subprocess` style
exit status.
"""
if os.WIFEXITED(status):
return os.WEXITSTATUS(status)
elif os.WIFSIGNALED(status):
return -os.WTERMSIG(status)
elif os.WIFSTOPPED(status):
return -os.WSTOPSIG(status)
class Process(mitogen.parent.Process):
def poll(self):
try:
pid, status = os.waitpid(self.pid, os.WNOHANG)
except OSError:
e = sys.exc_info()[1]
if e.args[0] == errno.ECHILD:
LOG.warn('%r: waitpid(%r) produced ECHILD', self, self.pid)
return
raise
if not pid:
return
return _convert_exit_status(status)
class Options(mitogen.parent.Options):
#: Reference to the importer, if any, recovered from the parent.
importer = None
#: User-supplied function for cleaning up child process state.
on_fork = None
def __init__(self, old_router, max_message_size, on_fork=None, debug=False,
profiling=False, unidirectional=False, on_start=None,
name=None):
if not FORK_SUPPORTED:
raise Error(self.python_version_msg)
# fork method only supports a tiny subset of options.
super(Options, self).__init__(
max_message_size=max_message_size, debug=debug,
profiling=profiling, unidirectional=unidirectional, name=name,
)
self.on_fork = on_fork
self.on_start = on_start
responder = getattr(old_router, 'responder', None)
if isinstance(responder, mitogen.parent.ModuleForwarder):
self.importer = responder.importer
class Connection(mitogen.parent.Connection):
options_class = Options
child_is_immediate_subprocess = True
python_version_msg = (
"The mitogen.fork method is not supported on Python versions "
"prior to 2.6, since those versions made no attempt to repair "
"critical interpreter state following a fork. Please use the "
"local() method instead."
)
name_prefix = u'fork'
def start_child(self):
parentfp, childfp = mitogen.parent.create_socketpair()
pid = os.fork()
if pid:
childfp.close()
return Process(pid, stdin=parentfp, stdout=parentfp)
else:
parentfp.close()
self._wrap_child_main(childfp)
def _wrap_child_main(self, childfp):
try:
self._child_main(childfp)
except BaseException:
handle_child_crash()
def get_econtext_config(self):
config = super(Connection, self).get_econtext_config()
config['core_src_fd'] = None
config['importer'] = self.options.importer
config['send_ec2'] = False
config['setup_package'] = False
if self.options.on_start:
config['on_start'] = self.options.on_start
return config
def _child_main(self, childfp):
on_fork()
if self.options.on_fork:
self.options.on_fork()
mitogen.core.set_block(childfp.fileno())
childfp.send(b('MITO002\n'))
# Expected by the ExternalContext.main().
os.dup2(childfp.fileno(), 1)
os.dup2(childfp.fileno(), 100)
# Overwritten by ExternalContext.main(); we must replace the
# parent-inherited descriptors that were closed by Side._on_fork() to
# avoid ExternalContext.main() accidentally allocating new files over
# the standard handles.
os.dup2(childfp.fileno(), 0)
# Avoid corrupting the stream on fork crash by dupping /dev/null over
# stderr. Instead, handle_child_crash() uses /dev/tty to log errors.
devnull = os.open('/dev/null', os.O_WRONLY)
if devnull != 2:
os.dup2(devnull, 2)
os.close(devnull)
# If we're unlucky, childfp.fileno() may coincidentally be one of our
# desired FDs. In that case closing it breaks ExternalContext.main().
if childfp.fileno() not in (0, 1, 100):
childfp.close()
mitogen.core.IOLOG.setLevel(logging.INFO)
try:
try:
mitogen.core.ExternalContext(self.get_econtext_config()).main()
except Exception:
# TODO: report exception somehow.
os._exit(72)
finally:
# Don't trigger atexit handlers, they were copied from the parent.
os._exit(0)
|