#! @PYTHON@ # Copyright (C) 2001-2006 by the Free Software Foundation, 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 the Free Software Foundation; either version 2 # of the License, or (at your option) any later version. # # This program is distributed in the hope that it will be useful, # but WITHOUT ANY WARRANTY; without even the implied warranty of # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the # GNU General Public License for more details. # # You should have received a copy of the GNU General Public License # along with this program; if not, write to the Free Software # Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, # USA. """Primary start-up and shutdown script for Mailman's qrunner daemon. This script starts, stops, and restarts the main Mailman queue runners, making sure that the various long-running qrunners are still alive and kicking. It does this by forking and exec'ing the qrunners and waiting on their pids. When it detects a subprocess has exited, it may restart it. The qrunners respond to SIGINT, SIGTERM, and SIGHUP. SIGINT and SIGTERM both cause the qrunners to exit cleanly, but the master will only restart qrunners that have exited due to a SIGINT. SIGHUP causes the master and the qrunners to close their log files, and reopen then upon the next printed message. The master also responds to SIGINT, SIGTERM, and SIGHUP, which it simply passes on to the qrunners (note that the master will close and reopen its own log files on receipt of a SIGHUP). The master also leaves its own process id in the file data/master-qrunner.pid but you normally don't need to use this pid directly. The `start', `stop', `restart', and `reopen' commands handle everything for you. Usage: %(PROGRAM)s [options] [ start | stop | restart | reopen ] Options: -n/--no-restart Don't restart the qrunners when they exit because of an error or a SIGINT. They are never restarted if they exit in response to a SIGTERM. Use this only for debugging. Only useful if the `start' command is given. -u/--run-as-user Normally, this script will refuse to run if the user id and group id are not set to the `mailman' user and group (as defined when you configured Mailman). If run as root, this script will change to this user and group before the check is made. This can be inconvenient for testing and debugging purposes, so the -u flag means that the step that sets and checks the uid/gid is skipped, and the program is run as the current user and group. This flag is not recommended for normal production environments. Note though, that if you run with -u and are not in the mailman group, you may have permission problems, such as begin unable to delete a list's archives through the web. Tough luck! -s/--stale-lock-cleanup If mailmanctl finds an existing master lock, it will normally exit with an error message. With this option, mailmanctl will perform an extra level of checking. If a process matching the host/pid described in the lock file is running, mailmanctl will still exit, but if no matching process is found, mailmanctl will remove the apparently stale lock and make another attempt to claim the master lock. -q/--quiet Don't print status messages. Error messages are still printed to standard error. -h/--help Print this message and exit. Commands: start - Start the master daemon and all qrunners. Prints a message and exits if the master daemon is already running. stop - Stops the master daemon and all qrunners. After stopping, no more messages will be processed. restart - Restarts the qrunners, but not the master process. Use this whenever you upgrade or update Mailman so that the qrunners will use the newly installed code. reopen - This will close all log files, causing them to be re-opened the next time a message is written to them """ import sys import os import time import getopt import signal import errno import pwd import grp import socket import paths from Mailman import mm_cfg from Mailman import Utils from Mailman import LockFile from Mailman import Errors from Mailman.MailList import MailList from Mailman.i18n import _ from Mailman.Logging.Syslog import syslog from Mailman.Logging.Utils import LogStdErr PROGRAM = sys.argv[0] COMMASPACE = ', ' DOT = '.' # Locking contantsa LOCKFILE = os.path.join(mm_cfg.LOCK_DIR, 'master-qrunner') # Since we wake up once per day and refresh the lock, the LOCK_LIFETIME # needn't be (much) longer than SNOOZE. We pad it 6 hours just to be safe. LOCK_LIFETIME = mm_cfg.days(1) + mm_cfg.hours(6) SNOOZE = mm_cfg.days(1) MAX_RESTARTS = 10 LogStdErr('error', 'mailmanctl', manual_reprime=0) def usage(code, msg=''): if code: fd = sys.stderr else: fd = sys.stdout print >> fd, _(__doc__) if msg: print >> fd, msg sys.exit(code) def kill_watcher(sig): try: fp = open(mm_cfg.PIDFILE) pidstr = fp.read() fp.close() pid = int(pidstr.strip()) except (IOError, ValueError), e: # For i18n convenience pidfile = mm_cfg.PIDFILE print >> sys.stderr, _('PID unreadable in: %(pidfile)s') print >> sys.stderr, e print >> sys.stderr, _('Is qrunner even running?') return try: os.kill(pid, sig) except OSError, e: if e.errno <> errno.ESRCH: raise print >> sys.stderr, _('No child with pid: %(pid)s') print >> sys.stderr, e print >> sys.stderr, _('Stale pid file removed.') os.unlink(mm_cfg.PIDFILE) def get_lock_data(): # Return the hostname, pid, and tempfile fp = open(LOCKFILE) filename = os.path.split(fp.read().strip())[1] fp.close() parts = filename.split('.') hostname = DOT.join(parts[1:-1]) pid = int(parts[-1]) return hostname, int(pid), filename def qrunner_state(): # 1 if proc exists on host (but is it qrunner? ;) # 0 if host matches but no proc # hostname if hostname doesn't match hostname, pid, tempfile = get_lock_data() if hostname <> socket.gethostname(): return hostname # Find out if the process exists by calling kill with a signal 0. try: os.kill(pid, 0) except OSError, e: if e.errno <> errno.ESRCH: raise return 0 return 1 def acquire_lock_1(force): # Be sure we can acquire the master qrunner lock. If not, it means some # other master qrunner daemon is already going. lock = LockFile.LockFile(LOCKFILE, LOCK_LIFETIME) try: lock.lock(0.1) return lock except LockFile.TimeOutError: if not force: raise # Force removal of lock first lock._disown() hostname, pid, tempfile = get_lock_data() os.unlink(LOCKFILE) os.unlink(os.path.join(mm_cfg.LOCK_DIR, tempfile)) return acquire_lock_1(force=0) def acquire_lock(force): try: lock = acquire_lock_1(force) return lock except LockFile.TimeOutError: status = qrunner_state() if status == 1: # host matches and proc exists print >> sys.stderr, _("""\ The master qrunner lock could not be acquired because it appears as if another master qrunner is already running. """) elif status == 0: # host matches but no proc print >> sys.stderr, _("""\ The master qrunner lock could not be acquired. It appears as though there is a stale master qrunner lock. Try re-running mailmanctl with the -s flag. """) else: # host doesn't even match print >> sys.stderr, _("""\ The master qrunner lock could not be acquired, because it appears as if some process on some other host may have acquired it. We can't test for stale locks across host boundaries, so you'll have to do this manually. Or, if you know the lock is stale, re-run mailmanctl with the -s flag. Lock file: %(LOCKFILE)s Lock host: %(status)s Exiting.""") def start_runner(qrname, slice, count): pid = os.fork() if pid: # parent return pid # child # # Craft the command line arguments for the exec() call. rswitch = '--runner=%s:%d:%d' % (qrname, slice, count) exe = os.path.join(mm_cfg.BIN_DIR, 'qrunner') # mm_cfg.PYTHON, which is the absolute path to the Python interpreter, # must be given as argv[0] due to Python's library search algorithm. os.execl(mm_cfg.PYTHON, mm_cfg.PYTHON, exe, rswitch, '-s') # Should never get here raise RuntimeError, 'os.execl() failed' def start_all_runners(): kids = {} for qrname, count in mm_cfg.QRUNNERS: for slice in range(count): # queue runner name, slice, numslices, restart count info = (qrname, slice, count, 0) pid = start_runner(qrname, slice, count) kids[pid] = info return kids def check_for_site_list(): sitelistname = mm_cfg.MAILMAN_SITE_LIST try: sitelist = MailList(sitelistname, lock=0) except Errors.MMUnknownListError: print >> sys.stderr, _('Site list is missing: %(sitelistname)s') syslog('error', 'Site list is missing: %s', mm_cfg.MAILMAN_SITE_LIST) sys.exit(1) def check_privs(): # If we're running as root (uid == 0), coerce the uid and gid to that # which Mailman was configured for, and refuse to run if we didn't coerce # the uid/gid. gid = grp.getgrnam(mm_cfg.MAILMAN_GROUP)[2] uid = pwd.getpwnam(mm_cfg.MAILMAN_USER)[2] myuid = os.getuid() if myuid == 0: # Set the process's supplimental groups. groups = [x[2] for x in grp.getgrall() if mm_cfg.MAILMAN_USER in x[3]] groups.append(gid) try: os.setgroups(groups) except AttributeError: # Python 2.1 doesn't have setgroups syslog('error', 'Warning: unable to setgroups(%s)' % groups) os.setgid(gid) os.setuid(uid) elif myuid <> uid: name = mm_cfg.MAILMAN_USER usage(1, _( 'Run this program as root or as the %(name)s user, or use -u.')) def main(): global quiet try: opts, args = getopt.getopt(sys.argv[1:], 'hnusq', ['help', 'no-start', 'run-as-user', 'stale-lock-cleanup', 'quiet']) except getopt.error, msg: usage(1, msg) restart = 1 checkprivs = 1 force = 0 quiet = 0 for opt, arg in opts: if opt in ('-h', '--help'): usage(0) elif opt in ('-n', '--no-restart'): restart = 0 elif opt in ('-u', '--run-as-user'): checkprivs = 0 elif opt in ('-s', '--stale-lock-cleanup'): force = 1 elif opt in ('-q', '--quiet'): quiet = 1 if len(args) < 1: usage(1, _('No command given.')) elif len(args) > 1: command = COMMASPACE.join(args) usage(1, _('Bad command: %(command)s')) if checkprivs: check_privs() else: print _('Warning! You may encounter permission problems.') # Handle the commands command = args[0].lower() if command == 'stop': # Sent the master qrunner process a SIGINT, which is equivalent to # giving cron/qrunner a ctrl-c or KeyboardInterrupt. This will # effectively shut everything down. if not quiet: print _("Shutting down Mailman's master qrunner") kill_watcher(signal.SIGTERM) elif command == 'restart': # Sent the master qrunner process a SIGHUP. This will cause the # master qrunner to kill and restart all the worker qrunners, and to # close and re-open its log files. if not quiet: print _("Restarting Mailman's master qrunner") kill_watcher(signal.SIGINT) elif command == 'reopen': if not quiet: print _('Re-opening all log files') kill_watcher(signal.SIGHUP) elif command == 'start': # First, complain loudly if there's no site list. check_for_site_list() # Here's the scoop on the processes we're about to create. We'll need # one for each qrunner, and one for a master child process watcher / # lock refresher process. # # The child watcher process simply waits on the pids of the children # qrunners. Unless explicitly disabled by a mailmanctl switch (or the # children are killed with SIGTERM instead of SIGINT), the watcher # will automatically restart any child process that exits. This # allows us to be more robust, and also to implement restart by simply # SIGINT'ing the qrunner children, and letting the watcher restart # them. # # Under normal operation, we have a child per queue. This lets us get # the most out of the available resources, since a qrunner with no # files in its queue directory is pretty cheap, but having a separate # runner process per queue allows for a very responsive system. Some # people want a more traditional (i.e. MM2.0.x) cron-invoked qrunner. # No problem, but using mailmanctl isn't the answer. So while # mailmanctl hard codes some things, others, such as the number of # qrunners per queue, is configurable in mm_cfg.py. # # First, acquire the master mailmanctl lock lock = acquire_lock(force) if not lock: return # Daemon process startup according to Stevens, Advanced Programming in # the UNIX Environment, Chapter 13. pid = os.fork() if pid: # parent if not quiet: print _("Starting Mailman's master qrunner.") # Give up the lock "ownership". This just means the foreground # process won't close/unlock the lock when it finalizes this lock # instance. We'll let the mater watcher subproc own the lock. lock._transfer_to(pid) return # child lock._take_possession() # First, save our pid in a file for "mailmanctl stop" rendezvous. We # want the perms on the .pid file to be rw-rw---- omask = os.umask(6) try: fp = open(mm_cfg.PIDFILE, 'w') print >> fp, os.getpid() fp.close() finally: os.umask(omask) # Create a new session and become the session leader, but since we # won't be opening any terminal devices, don't do the ultra-paranoid # suggestion of doing a second fork after the setsid() call. os.setsid() # Instead of cd'ing to root, cd to the Mailman installation home os.chdir(mm_cfg.PREFIX) # Set our file mode creation umask os.umask(007) # I don't think we have any unneeded file descriptors. # # Now start all the qrunners. This returns a dictionary where the # keys are qrunner pids and the values are tuples of the following # form: (qrname, slice, count). This does its own fork and exec, and # sets up its own signal handlers. kids = start_all_runners() # Set up a SIGALRM handler to refresh the lock once per day. The lock # lifetime is 1day+6hours so this should be plenty. def sigalrm_handler(signum, frame, lock=lock): lock.refresh() signal.alarm(mm_cfg.days(1)) signal.signal(signal.SIGALRM, sigalrm_handler) signal.alarm(mm_cfg.days(1)) # Set up a SIGHUP handler so that if we get one, we'll pass it along # to all the qrunner children. This will tell them to close and # reopen their log files def sighup_handler(signum, frame, kids=kids): # Closing our syslog will cause it to be re-opened at the next log # print output. syslog.close() for pid in kids.keys(): os.kill(pid, signal.SIGHUP) # And just to tweak things... syslog('qrunner', 'Master watcher caught SIGHUP. Re-opening log files.') signal.signal(signal.SIGHUP, sighup_handler) # We also need to install a SIGTERM handler because that's what init # will kill this process with when changing run levels. def sigterm_handler(signum, frame, kids=kids): for pid in kids.keys(): try: os.kill(pid, signal.SIGTERM) except OSError, e: if e.errno <> errno.ESRCH: raise syslog('qrunner', 'Master watcher caught SIGTERM. Exiting.') signal.signal(signal.SIGTERM, sigterm_handler) # Finally, we need a SIGINT handler which will cause the sub-qrunners # to exit, but the master will restart SIGINT'd sub-processes unless # the -n flag was given. def sigint_handler(signum, frame, kids=kids): for pid in kids.keys(): os.kill(pid, signal.SIGINT) syslog('qrunner', 'Master watcher caught SIGINT. Restarting.') signal.signal(signal.SIGINT, sigint_handler) # Now we're ready to simply do our wait/restart loop. This is the # master qrunner watcher. try: while 1: try: pid, status = os.wait() except OSError, e: # No children? We're done if e.errno == errno.ECHILD: break # If the system call got interrupted, just restart it. elif e.errno <> errno.EINTR: raise continue killsig = exitstatus = None if os.WIFSIGNALED(status): killsig = os.WTERMSIG(status) if os.WIFEXITED(status): exitstatus = os.WEXITSTATUS(status) # We'll restart the process unless we were given the # "no-restart" switch, or if the process was SIGTERM'd or # exitted with a SIGTERM exit status. This lets us better # handle runaway restarts (say, if the subproc had a syntax # error!) restarting = '' if restart: if (exitstatus == None and killsig <> signal.SIGTERM) or \ (killsig == None and exitstatus <> signal.SIGTERM): # Then restarting = '[restarting]' qrname, slice, count, restarts = kids[pid] del kids[pid] syslog('qrunner', """\ Master qrunner detected subprocess exit (pid: %d, sig: %s, sts: %s, class: %s, slice: %d/%d) %s""", pid, killsig, exitstatus, qrname, slice+1, count, restarting) # See if we've reached the maximum number of allowable restarts if exitstatus <> signal.SIGINT: restarts += 1 if restarts > MAX_RESTARTS: syslog('qrunner', """\ Qrunner %s reached maximum restart limit of %d, not restarting.""", qrname, MAX_RESTARTS) restarting = '' # Now perhaps restart the process unless it exited with a # SIGTERM or we aren't restarting. if restarting: newpid = start_runner(qrname, slice, count) kids[newpid] = (qrname, slice, count, restarts) finally: # Should we leave the main loop for any reason, we want to be sure # all of our children are exited cleanly. Send SIGTERMs to all # the child processes and wait for them all to exit. for pid in kids.keys(): try: os.kill(pid, signal.SIGTERM) except OSError, e: if e.errno == errno.ESRCH: # The child has already exited syslog('qrunner', 'ESRCH on pid: %d', pid) del kids[pid] # Wait for all the children to go away while 1: try: pid, status = os.wait() except OSError, e: if e.errno == errno.ECHILD: break elif e.errno <> errno.EINTR: raise continue # Finally, give up the lock lock.unlock(unconditionally=1) os._exit(0) if __name__ == '__main__': main()