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![Erik Johnston](/assets/img/avatar_default.png)
During the migration the automated script to update the copyright headers accidentally got rid of some of the existing copyright lines. Reinstate them.
150 lines
5.1 KiB
Python
150 lines
5.1 KiB
Python
#
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# This file is licensed under the Affero General Public License (AGPL) version 3.
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#
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# Copyright 2020 The Matrix.org Foundation C.I.C.
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# Copyright (c) 2012, 2013, 2014 Ilya Otyutskiy <ilya.otyutskiy@icloud.com>
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# Copyright (C) 2023 New Vector, Ltd
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU Affero General Public License as
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# published by the Free Software Foundation, either version 3 of the
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# License, or (at your option) any later version.
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#
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# See the GNU Affero General Public License for more details:
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# <https://www.gnu.org/licenses/agpl-3.0.html>.
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#
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# Originally licensed under the Apache License, Version 2.0:
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# <http://www.apache.org/licenses/LICENSE-2.0>.
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#
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# [This file includes modifications made by New Vector Limited]
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#
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#
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import atexit
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import fcntl
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import logging
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import os
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import signal
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import sys
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from types import FrameType, TracebackType
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from typing import NoReturn, Optional, Type
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def daemonize_process(pid_file: str, logger: logging.Logger, chdir: str = "/") -> None:
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"""daemonize the current process
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This calls fork(), and has the main process exit. When it returns we will be
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running in the child process.
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"""
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# If pidfile already exists, we should read pid from there; to overwrite it, if
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# locking will fail, because locking attempt somehow purges the file contents.
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if os.path.isfile(pid_file):
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with open(pid_file) as pid_fh:
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old_pid = pid_fh.read()
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# Create a lockfile so that only one instance of this daemon is running at any time.
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try:
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lock_fh = open(pid_file, "w")
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except OSError:
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print("Unable to create the pidfile.")
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sys.exit(1)
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try:
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# Try to get an exclusive lock on the file. This will fail if another process
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# has the file locked.
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fcntl.flock(lock_fh, fcntl.LOCK_EX | fcntl.LOCK_NB)
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except OSError:
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print("Unable to lock on the pidfile.")
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# We need to overwrite the pidfile if we got here.
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#
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# XXX better to avoid overwriting it, surely. this looks racey as the pid file
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# could be created between us trying to read it and us trying to lock it.
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with open(pid_file, "w") as pid_fh:
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pid_fh.write(old_pid)
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sys.exit(1)
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# Fork, creating a new process for the child.
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process_id = os.fork()
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if process_id != 0:
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# parent process: exit.
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# we use os._exit to avoid running the atexit handlers. In particular, that
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# means we don't flush the logs. This is important because if we are using
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# a MemoryHandler, we could have logs buffered which are now buffered in both
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# the main and the child process, so if we let the main process flush the logs,
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# we'll get two copies.
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os._exit(0)
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# This is the child process. Continue.
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# Stop listening for signals that the parent process receives.
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# This is done by getting a new process id.
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# setpgrp() is an alternative to setsid().
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# setsid puts the process in a new parent group and detaches its controlling
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# terminal.
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os.setsid()
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# point stdin, stdout, stderr at /dev/null
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devnull = "/dev/null"
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if hasattr(os, "devnull"):
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# Python has set os.devnull on this system, use it instead as it might be
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# different than /dev/null.
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devnull = os.devnull
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devnull_fd = os.open(devnull, os.O_RDWR)
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os.dup2(devnull_fd, 0)
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os.dup2(devnull_fd, 1)
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os.dup2(devnull_fd, 2)
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os.close(devnull_fd)
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# now that we have redirected stderr to /dev/null, any uncaught exceptions will
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# get sent to /dev/null, so make sure we log them.
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#
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# (we don't normally expect reactor.run to raise any exceptions, but this will
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# also catch any other uncaught exceptions before we get that far.)
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def excepthook(
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type_: Type[BaseException],
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value: BaseException,
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traceback: Optional[TracebackType],
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) -> None:
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logger.critical("Unhanded exception", exc_info=(type_, value, traceback))
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sys.excepthook = excepthook
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# Set umask to default to safe file permissions when running as a root daemon. 027
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# is an octal number which we are typing as 0o27 for Python3 compatibility.
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os.umask(0o27)
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# Change to a known directory. If this isn't done, starting a daemon in a
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# subdirectory that needs to be deleted results in "directory busy" errors.
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os.chdir(chdir)
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try:
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lock_fh.write("%s" % (os.getpid()))
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lock_fh.flush()
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except OSError:
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logger.error("Unable to write pid to the pidfile.")
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print("Unable to write pid to the pidfile.")
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sys.exit(1)
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# write a log line on SIGTERM.
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def sigterm(signum: int, frame: Optional[FrameType]) -> NoReturn:
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logger.warning("Caught signal %s. Stopping daemon." % signum)
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sys.exit(0)
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signal.signal(signal.SIGTERM, sigterm)
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# Cleanup pid file at exit.
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def exit() -> None:
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logger.warning("Stopping daemon.")
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os.remove(pid_file)
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sys.exit(0)
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atexit.register(exit)
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logger.warning("Starting daemon.")
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