X-Git-Url: https://code.grnet.gr/git/ganeti-local/blobdiff_plain/0070a46214010a677d8b89ff1091113fa550850d..86aa9ba32f810956948ff4e578c828351998a82c:/lib/daemon.py diff --git a/lib/daemon.py b/lib/daemon.py index 9897ee2..62ea1f4 100644 --- a/lib/daemon.py +++ b/lib/daemon.py @@ -1,7 +1,7 @@ # # -# Copyright (C) 2006, 2007, 2008, 2010 Google Inc. +# Copyright (C) 2006, 2007, 2008, 2010, 2011, 2012 Google Inc. # # This program is free software; you can redistribute it and/or modify # it under the terms of the GNU General Public License as published by @@ -39,6 +39,8 @@ from ganeti import constants from ganeti import errors from ganeti import netutils from ganeti import ssconf +from ganeti import runtime +from ganeti import compat class SchedulerBreakout(Exception): @@ -73,7 +75,43 @@ class AsyncoreScheduler(sched.scheduler): """ def __init__(self, timefunc): - sched.scheduler.__init__(self, timefunc, AsyncoreDelayFunction) + """Initializes this class. + + """ + sched.scheduler.__init__(self, timefunc, self._LimitedDelay) + self._max_delay = None + + def run(self, max_delay=None): # pylint: disable=W0221 + """Run any pending events. + + @type max_delay: None or number + @param max_delay: Maximum delay (useful if caller has timeouts running) + + """ + assert self._max_delay is None + + # The delay function used by the scheduler can't be different on each run, + # hence an instance variable must be used. + if max_delay is None: + self._max_delay = None + else: + self._max_delay = utils.RunningTimeout(max_delay, False) + + try: + return sched.scheduler.run(self) + finally: + self._max_delay = None + + def _LimitedDelay(self, duration): + """Custom delay function for C{sched.scheduler}. + + """ + if self._max_delay is None: + timeout = duration + else: + timeout = min(duration, self._max_delay.Remaining()) + + return AsyncoreDelayFunction(timeout) class GanetiBaseAsyncoreDispatcher(asyncore.dispatcher): @@ -344,7 +382,7 @@ class AsyncUDPSocket(GanetiBaseAsyncoreDispatcher): """ if len(payload) > constants.MAX_UDP_DATA_SIZE: - raise errors.UdpDataSizeError('Packet too big: %s > %s' % (len(payload), + raise errors.UdpDataSizeError("Packet too big: %s > %s" % (len(payload), constants.MAX_UDP_DATA_SIZE)) self._out_queue.append((ip, port, payload)) @@ -382,7 +420,7 @@ class AsyncAwaker(GanetiBaseAsyncoreDispatcher): """ GanetiBaseAsyncoreDispatcher.__init__(self) - assert signal_fn == None or callable(signal_fn) + assert signal_fn is None or callable(signal_fn) (self.in_socket, self.out_socket) = socket.socketpair(socket.AF_UNIX, socket.SOCK_STREAM) self.in_socket.setblocking(0) @@ -419,6 +457,47 @@ class AsyncAwaker(GanetiBaseAsyncoreDispatcher): self.out_socket.send("\0") +class _ShutdownCheck: + """Logic for L{Mainloop} shutdown. + + """ + def __init__(self, fn): + """Initializes this class. + + @type fn: callable + @param fn: Function returning C{None} if mainloop can be stopped or a + duration in seconds after which the function should be called again + @see: L{Mainloop.Run} + + """ + assert callable(fn) + + self._fn = fn + self._defer = None + + def CanShutdown(self): + """Checks whether mainloop can be stopped. + + @rtype: bool + + """ + if self._defer and self._defer.Remaining() > 0: + # A deferred check has already been scheduled + return False + + # Ask mainloop driver whether we can stop or should check again + timeout = self._fn() + + if timeout is None: + # Yes, can stop mainloop + return True + + # Schedule another check in the future + self._defer = utils.RunningTimeout(timeout, True) + + return False + + class Mainloop(object): """Generic mainloop for daemons @@ -426,6 +505,8 @@ class Mainloop(object): timed events """ + _SHUTDOWN_TIMEOUT_PRIORITY = -(sys.maxint - 1) + def __init__(self): """Constructs a new Mainloop instance. @@ -433,12 +514,19 @@ class Mainloop(object): self._signal_wait = [] self.scheduler = AsyncoreScheduler(time.time) + # Resolve uid/gids used + runtime.GetEnts() + @utils.SignalHandled([signal.SIGCHLD]) @utils.SignalHandled([signal.SIGTERM]) @utils.SignalHandled([signal.SIGINT]) - def Run(self, signal_handlers=None): + def Run(self, shutdown_wait_fn=None, signal_handlers=None): """Runs the mainloop. + @type shutdown_wait_fn: callable + @param shutdown_wait_fn: Function to check whether loop can be terminated; + B{important}: function must be idempotent and must return either None + for shutting down or a timeout for another call @type signal_handlers: dict @param signal_handlers: signal->L{utils.SignalHandler} passed by decorator @@ -446,23 +534,50 @@ class Mainloop(object): assert isinstance(signal_handlers, dict) and \ len(signal_handlers) > 0, \ "Broken SignalHandled decorator" - running = True + + # Counter for received signals + shutdown_signals = 0 + + # Logic to wait for shutdown + shutdown_waiter = None + # Start actual main loop - while running: - if not self.scheduler.empty(): + while True: + if shutdown_signals == 1 and shutdown_wait_fn is not None: + if shutdown_waiter is None: + shutdown_waiter = _ShutdownCheck(shutdown_wait_fn) + + # Let mainloop driver decide if we can already abort + if shutdown_waiter.CanShutdown(): + break + + # Re-evaluate in a second + timeout = 1.0 + + elif shutdown_signals >= 1: + # Abort loop if more than one signal has been sent or no callback has + # been given + break + + else: + # Wait forever on I/O events + timeout = None + + if self.scheduler.empty(): + asyncore.loop(count=1, timeout=timeout, use_poll=True) + else: try: - self.scheduler.run() + self.scheduler.run(max_delay=timeout) except SchedulerBreakout: pass - else: - asyncore.loop(count=1, use_poll=True) # Check whether a signal was raised - for sig in signal_handlers: - handler = signal_handlers[sig] + for (sig, handler) in signal_handlers.items(): if handler.called: self._CallSignalWaiters(sig) - running = sig not in (signal.SIGTERM, signal.SIGINT) + if sig in (signal.SIGTERM, signal.SIGINT): + logging.info("Received signal %s asking for shutdown", sig) + shutdown_signals += 1 handler.Clear() def _CallSignalWaiters(self, signum): @@ -487,7 +602,73 @@ class Mainloop(object): self._signal_wait.append(owner) -def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn, +def _VerifyDaemonUser(daemon_name): + """Verifies the process uid matches the configured uid. + + This method verifies that a daemon is started as the user it is + intended to be run + + @param daemon_name: The name of daemon to be started + @return: A tuple with the first item indicating success or not, + the second item current uid and third with expected uid + + """ + getents = runtime.GetEnts() + running_uid = os.getuid() + daemon_uids = { + constants.MASTERD: getents.masterd_uid, + constants.RAPI: getents.rapi_uid, + constants.NODED: getents.noded_uid, + constants.CONFD: getents.confd_uid, + } + assert daemon_name in daemon_uids, "Invalid daemon %s" % daemon_name + + return (daemon_uids[daemon_name] == running_uid, running_uid, + daemon_uids[daemon_name]) + + +def _BeautifyError(err): + """Try to format an error better. + + Since we're dealing with daemon startup errors, in many cases this + will be due to socket error and such, so we try to format these cases better. + + @param err: an exception object + @rtype: string + @return: the formatted error description + + """ + try: + if isinstance(err, socket.error): + return "Socket-related error: %s (errno=%s)" % (err.args[1], err.args[0]) + elif isinstance(err, EnvironmentError): + if err.filename is None: + return "%s (errno=%s)" % (err.strerror, err.errno) + else: + return "%s (file %s) (errno=%s)" % (err.strerror, err.filename, + err.errno) + else: + return str(err) + except Exception: # pylint: disable=W0703 + logging.exception("Error while handling existing error %s", err) + return "%s" % str(err) + + +def _HandleSigHup(reopen_fn, signum, frame): # pylint: disable=W0613 + """Handler for SIGHUP. + + @param reopen_fn: List of callback functions for reopening log files + + """ + logging.info("Reopening log files after receiving SIGHUP") + + for fn in reopen_fn: + if fn: + fn() + + +def GenericMain(daemon_name, optionparser, + check_fn, prepare_fn, exec_fn, multithreaded=False, console_logging=False, default_ssl_cert=None, default_ssl_key=None): """Shared main function for daemons. @@ -497,13 +678,14 @@ def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn, @type optionparser: optparse.OptionParser @param optionparser: initialized optionparser with daemon-specific options (common -f -d options will be handled by this module) - @type dirs: list of (string, integer) - @param dirs: list of directories that must be created if they don't exist, - and the permissions to be used to create them @type check_fn: function which accepts (options, args) @param check_fn: function that checks start conditions and exits if they're not met - @type exec_fn: function which accepts (options, args) + @type prepare_fn: function which accepts (options, args) + @param prepare_fn: function that is run before forking, or None; + it's result will be passed as the third parameter to exec_fn, or + if None was passed in, we will just pass None to exec_fn + @type exec_fn: function which accepts (options, args, prepare_results) @param exec_fn: function that's executed with the daemon's pid file held, and runs the daemon itself. @type multithreaded: bool @@ -566,7 +748,8 @@ def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn, metavar="SSL_CERT_PATH") # Disable the use of fork(2) if the daemon uses threads - utils.no_fork = multithreaded + if multithreaded: + utils.DisableFork() options, args = optionparser.parse_args() @@ -585,25 +768,58 @@ def GenericMain(daemon_name, optionparser, dirs, check_fn, exec_fn, # once and have a proper validation (isfile returns False on directories) # at the same time. + result, running_uid, expected_uid = _VerifyDaemonUser(daemon_name) + if not result: + msg = ("%s started using wrong user ID (%d), expected %d" % + (daemon_name, running_uid, expected_uid)) + print >> sys.stderr, msg + sys.exit(constants.EXIT_FAILURE) + if check_fn is not None: check_fn(options, args) - utils.EnsureDirs(dirs) + log_filename = constants.DAEMONS_LOGFILES[daemon_name] if options.fork: utils.CloseFDs() - utils.Daemonize(logfile=constants.DAEMONS_LOGFILES[daemon_name]) + (wpipe, stdio_reopen_fn) = utils.Daemonize(logfile=log_filename) + else: + (wpipe, stdio_reopen_fn) = (None, None) - utils.WritePidFile(daemon_name) - try: - utils.SetupLogging(logfile=constants.DAEMONS_LOGFILES[daemon_name], + log_reopen_fn = \ + utils.SetupLogging(log_filename, daemon_name, debug=options.debug, stderr_logging=not options.fork, multithreaded=multithreaded, - program=daemon_name, syslog=options.syslog, console_logging=console_logging) - logging.info("%s daemon startup", daemon_name) - exec_fn(options, args) + + # Reopen log file(s) on SIGHUP + signal.signal(signal.SIGHUP, + compat.partial(_HandleSigHup, [log_reopen_fn, stdio_reopen_fn])) + + try: + utils.WritePidFile(utils.DaemonPidFileName(daemon_name)) + except errors.PidFileLockError, err: + print >> sys.stderr, "Error while locking PID file:\n%s" % err + sys.exit(constants.EXIT_FAILURE) + + try: + try: + logging.info("%s daemon startup", daemon_name) + if callable(prepare_fn): + prep_results = prepare_fn(options, args) + else: + prep_results = None + except Exception, err: + utils.WriteErrorToFD(wpipe, _BeautifyError(err)) + raise + + if wpipe is not None: + # we're done with the preparation phase, we close the pipe to + # let the parent know it's safe to exit + os.close(wpipe) + + exec_fn(options, args, prep_results) finally: - utils.RemovePidFile(daemon_name) + utils.RemoveFile(utils.DaemonPidFileName(daemon_name))