0121cb2fd4
If getting memory for new VM fails for any reason, make sure that global lock will be released. Otherwise qmemman will stop functioning at all. QubesOS/qubes-issues#1636
289 lines
9.9 KiB
Python
Executable File
289 lines
9.9 KiB
Python
Executable File
#!/usr/bin/python2
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# -*- coding: utf-8 -*-
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#
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# The Qubes OS Project, http://www.qubes-os.org
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#
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# Copyright (C) 2010 Rafal Wojtczuk <rafal@invisiblethingslab.com>
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#
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# This program is free software; you can redistribute it and/or
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# modify it under the terms of the GNU General Public License
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# as published by the Free Software Foundation; either version 2
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# of the License, or (at your option) any later version.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program; if not, write to the Free Software
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# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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#
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#
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import SocketServer
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import thread
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import time
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import xen.lowlevel.xs
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import sys
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import os
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import socket
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from qmemman import SystemState
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import qmemman_algo
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from ConfigParser import SafeConfigParser
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from optparse import OptionParser
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from qubesutils import parse_size
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import logging
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import logging.handlers
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config_path = '/etc/qubes/qmemman.conf'
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SOCK_PATH='/var/run/qubes/qmemman.sock'
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LOG_PATH='/var/log/qubes/qmemman.log'
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system_state = SystemState()
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global_lock = thread.allocate_lock()
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# If XS_Watcher will
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# handle meminfo event before @introduceDomain, it will use
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# incomplete domain list for that and may redistribute memory
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# allocated to some VM, but not yet used (see #1389).
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# To fix that, system_state should be updated (refresh domain
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# list) before processing other changes, every time some process requested
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# memory for a new VM, before releasing the lock. Then XS_Watcher will check
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# this flag before processing other event.
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force_refresh_domain_list = False
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def only_in_first_list(l1, l2):
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ret=[]
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for i in l1:
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if not i in l2:
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ret.append(i)
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return ret
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def get_domain_meminfo_key(domain_id):
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return '/local/domain/'+domain_id+'/memory/meminfo'
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class WatchType:
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def __init__(self, fn, param):
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self.fn = fn
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self.param = param
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class XS_Watcher:
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def __init__(self):
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self.log = logging.getLogger('qmemman.daemon.xswatcher')
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self.log.debug('XS_Watcher()')
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self.handle = xen.lowlevel.xs.xs()
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self.handle.watch('@introduceDomain', WatchType(
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XS_Watcher.domain_list_changed, False))
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self.handle.watch('@releaseDomain', WatchType(
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XS_Watcher.domain_list_changed, False))
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self.watch_token_dict = {}
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def domain_list_changed(self, refresh_only=False):
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"""
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Check if any domain was created/destroyed. If it was, update
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appropriate list. Then redistribute memory.
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:param refresh_only If True, only refresh domain list, do not
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redistribute memory. In this mode, caller must already hold
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global_lock.
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"""
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self.log.debug('domain_list_changed(only_refresh={!r})'.format(
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refresh_only))
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got_lock = False
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if not refresh_only:
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self.log.debug('acquiring global_lock')
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global_lock.acquire()
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got_lock = True
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self.log.debug('global_lock acquired')
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try:
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curr = self.handle.ls('', '/local/domain')
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if curr is None:
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return
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# check if domain is really there, it may happen that some empty
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# directories are left in xenstore
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curr = filter(
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lambda x:
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self.handle.read('',
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'/local/domain/{}/domid'.format(x)
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) is not None,
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curr
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)
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self.log.debug('curr={!r}'.format(curr))
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for i in only_in_first_list(curr, self.watch_token_dict.keys()):
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# new domain has been created
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watch = WatchType(XS_Watcher.meminfo_changed, i)
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self.watch_token_dict[i] = watch
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self.handle.watch(get_domain_meminfo_key(i), watch)
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system_state.add_domain(i)
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for i in only_in_first_list(self.watch_token_dict.keys(), curr):
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# domain destroyed
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self.handle.unwatch(get_domain_meminfo_key(i), self.watch_token_dict[i])
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self.watch_token_dict.pop(i)
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system_state.del_domain(i)
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finally:
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if got_lock:
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global_lock.release()
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self.log.debug('global_lock released')
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if not refresh_only:
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system_state.do_balance()
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def meminfo_changed(self, domain_id):
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self.log.debug('meminfo_changed(domain_id={!r})'.format(domain_id))
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untrusted_meminfo_key = self.handle.read('', get_domain_meminfo_key(domain_id))
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if untrusted_meminfo_key == None or untrusted_meminfo_key == '':
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return
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self.log.debug('acquiring global_lock')
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global_lock.acquire()
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self.log.debug('global_lock acquired')
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if force_refresh_domain_list:
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self.domain_list_changed(refresh_only=True)
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system_state.refresh_meminfo(domain_id, untrusted_meminfo_key)
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global_lock.release()
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self.log.debug('global_lock released')
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def watch_loop(self):
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self.log.debug('watch_loop()')
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while True:
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result = self.handle.read_watch()
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self.log.debug('watch_loop result={!r}'.format(result))
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token = result[1]
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token.fn(self, token.param)
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class QMemmanReqHandler(SocketServer.BaseRequestHandler):
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"""
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The RequestHandler class for our server.
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It is instantiated once per connection to the server, and must
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override the handle() method to implement communication to the
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client.
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"""
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def handle(self):
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self.log = logging.getLogger('qmemman.daemon.reqhandler')
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got_lock = False
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try:
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# self.request is the TCP socket connected to the client
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while True:
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self.data = self.request.recv(1024).strip()
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self.log.debug('data={!r}'.format(self.data))
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if len(self.data) == 0:
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self.log.info('EOF')
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if got_lock:
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global force_refresh_domain_list
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force_refresh_domain_list = True
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return
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# XXX something is wrong here: return without release?
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if got_lock:
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self.log.warning('Second request over qmemman.sock?')
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return
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self.log.debug('acquiring global_lock')
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global_lock.acquire()
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self.log.debug('global_lock acquired')
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got_lock = True
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if system_state.do_balloon(int(self.data)):
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resp = "OK\n"
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else:
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resp = "FAIL\n"
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self.log.debug('resp={!r}'.format(resp))
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self.request.send(resp)
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except BaseException as e:
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self.log.exception(
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"exception while handling request: {!r}".format(e))
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finally:
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if got_lock:
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global_lock.release()
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self.log.debug('global_lock released')
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def start_server(server):
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server.serve_forever()
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class QMemmanServer:
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@staticmethod
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def main():
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# setup logging
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ha_syslog = logging.handlers.SysLogHandler('/dev/log')
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ha_syslog.setFormatter(
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logging.Formatter('%(name)s[%(process)d]: %(message)s'))
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logging.root.addHandler(ha_syslog)
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# leave log for backwards compatibility
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ha_file = logging.FileHandler(LOG_PATH)
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ha_file.setFormatter(
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logging.Formatter('%(asctime)s %(name)s[%(process)d]: %(message)s'))
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logging.root.addHandler(ha_file)
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log = logging.getLogger('qmemman.daemon')
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usage = "usage: %prog [options]"
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parser = OptionParser(usage)
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parser.add_option("-c", "--config", action="store", dest="config", default=config_path)
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parser.add_option("-d", "--debug", action="store_true", dest="debug",
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default=False, help="Enable debugging")
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(options, args) = parser.parse_args()
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if options.debug:
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logging.root.setLevel(logging.DEBUG)
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# close io
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sys.stdin.close()
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sys.stdout.close()
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sys.stderr.close()
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config = SafeConfigParser({
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'vm-min-mem': str(qmemman_algo.MIN_PREFMEM),
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'dom0-mem-boost': str(qmemman_algo.DOM0_MEM_BOOST),
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'cache-margin-factor': str(qmemman_algo.CACHE_FACTOR)
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})
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config.read(options.config)
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if config.has_section('global'):
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qmemman_algo.MIN_PREFMEM = parse_size(config.get('global', 'vm-min-mem'))
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qmemman_algo.DOM0_MEM_BOOST = parse_size(config.get('global', 'dom0-mem-boost'))
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qmemman_algo.CACHE_FACTOR = config.getfloat('global', 'cache-margin-factor')
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log.info('MIN_PREFMEM={qmemman_algo.MIN_PREFMEM}'
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' DOM0_MEM_BOOST={qmemman_algo.DOM0_MEM_BOOST}'
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' CACHE_FACTOR={qmemman_algo.CACHE_FACTOR}'.format(
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qmemman_algo=qmemman_algo))
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try:
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os.unlink(SOCK_PATH)
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except:
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pass
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log.debug('instantiating server')
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os.umask(0)
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server = SocketServer.UnixStreamServer(SOCK_PATH, QMemmanReqHandler)
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os.umask(077)
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# notify systemd
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nofity_socket = os.getenv('NOTIFY_SOCKET')
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if nofity_socket:
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log.debug('notifying systemd')
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s = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
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if nofity_socket.startswith('@'):
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nofity_socket = '\0%s' % nofity_socket[1:]
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s.connect(nofity_socket)
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s.sendall("READY=1")
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s.close()
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thread.start_new_thread(start_server, tuple([server]))
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XS_Watcher().watch_loop()
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