# IMAP server support # Copyright (C) 2002 - 2007 John Goerzen # # # 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 St, Fifth Floor, Boston, MA 02110-1301 USA from offlineimap import imaplibutil, imaputil, threadutil, OfflineImapError from offlineimap.ui import getglobalui from threading import Lock, BoundedSemaphore, Thread, Event, currentThread from thread import get_ident # python < 2.6 support import offlineimap.accounts import hmac import socket import base64 from socket import gaierror try: # do we have a recent pykerberos? have_gss = False import kerberos if 'authGSSClientWrap' in dir(kerberos): have_gss = True except ImportError: pass class IMAPServer: GSS_STATE_STEP = 0 GSS_STATE_WRAP = 1 def __init__(self, config, reposname, username = None, password = None, hostname = None, port = None, ssl = 1, maxconnections = 1, tunnel = None, reference = '""', sslclientcert = None, sslclientkey = None, sslcacertfile = None, idlefolders = []): self.ui = getglobalui() self.reposname = reposname self.config = config self.username = username self.password = password self.passworderror = None self.goodpassword = None self.hostname = hostname self.tunnel = tunnel self.port = port self.usessl = ssl self.sslclientcert = sslclientcert self.sslclientkey = sslclientkey self.sslcacertfile = sslcacertfile self.delim = None self.root = None if port == None: if ssl: self.port = 993 else: self.port = 143 self.maxconnections = maxconnections self.availableconnections = [] self.assignedconnections = [] self.lastowner = {} self.semaphore = BoundedSemaphore(self.maxconnections) self.connectionlock = Lock() self.reference = reference self.idlefolders = idlefolders self.gss_step = self.GSS_STATE_STEP self.gss_vc = None self.gssapi = False def getpassword(self): if self.goodpassword != None: return self.goodpassword if self.password != None and self.passworderror == None: return self.password self.password = self.ui.getpass(self.reposname, self.config, self.passworderror) self.passworderror = None return self.password def getdelim(self): """Returns this server's folder delimiter. Can only be called after one or more calls to acquireconnection.""" return self.delim def getroot(self): """Returns this server's folder root. Can only be called after one or more calls to acquireconnection.""" return self.root def releaseconnection(self, connection): """Releases a connection, returning it to the pool.""" self.connectionlock.acquire() self.assignedconnections.remove(connection) # Don't reuse broken connections if connection.Terminate: connection.logout() else: self.availableconnections.append(connection) self.connectionlock.release() self.semaphore.release() def md5handler(self, response): challenge = response.strip() self.ui.debug('imap', 'md5handler: got challenge %s' % challenge) passwd = self.getpassword() retval = self.username + ' ' + hmac.new(passwd, challenge).hexdigest() self.ui.debug('imap', 'md5handler: returning %s' % retval) return retval def plainauth(self, imapobj): self.ui.debug('imap', 'Attempting plain authentication') imapobj.login(self.username, self.getpassword()) def gssauth(self, response): data = base64.b64encode(response) try: if self.gss_step == self.GSS_STATE_STEP: if not self.gss_vc: rc, self.gss_vc = kerberos.authGSSClientInit('imap@' + self.hostname) response = kerberos.authGSSClientResponse(self.gss_vc) rc = kerberos.authGSSClientStep(self.gss_vc, data) if rc != kerberos.AUTH_GSS_CONTINUE: self.gss_step = self.GSS_STATE_WRAP elif self.gss_step == self.GSS_STATE_WRAP: rc = kerberos.authGSSClientUnwrap(self.gss_vc, data) response = kerberos.authGSSClientResponse(self.gss_vc) rc = kerberos.authGSSClientWrap(self.gss_vc, response, self.username) response = kerberos.authGSSClientResponse(self.gss_vc) except kerberos.GSSError, err: # Kerberos errored out on us, respond with None to cancel the # authentication self.ui.debug('imap', '%s: %s' % (err[0][0], err[1][0])) return None if not response: response = '' return base64.b64decode(response) def acquireconnection(self): """Fetches a connection from the pool, making sure to create a new one if needed, to obey the maximum connection limits, etc. Opens a connection to the server and returns an appropriate object.""" self.semaphore.acquire() self.connectionlock.acquire() imapobj = None if len(self.availableconnections): # One is available. # Try to find one that previously belonged to this thread # as an optimization. Start from the back since that's where # they're popped on. imapobj = None for i in range(len(self.availableconnections) - 1, -1, -1): tryobj = self.availableconnections[i] if self.lastowner[tryobj] == get_ident(): imapobj = tryobj del(self.availableconnections[i]) break if not imapobj: imapobj = self.availableconnections[0] del(self.availableconnections[0]) self.assignedconnections.append(imapobj) self.lastowner[imapobj] = get_ident() self.connectionlock.release() return imapobj self.connectionlock.release() # Release until need to modify data """ Must be careful here that if we fail we should bail out gracefully and release locks / threads so that the next attempt can try... """ success = 0 try: while not success: # Generate a new connection. if self.tunnel: self.ui.connecting('tunnel', self.tunnel) imapobj = imaplibutil.IMAP4_Tunnel(self.tunnel, timeout=socket.getdefaulttimeout()) success = 1 elif self.usessl: self.ui.connecting(self.hostname, self.port) imapobj = imaplibutil.WrappedIMAP4_SSL(self.hostname, self.port, self.sslclientkey, self.sslclientcert, timeout=socket.getdefaulttimeout(), cacertfile = self.sslcacertfile) else: self.ui.connecting(self.hostname, self.port) imapobj = imaplibutil.WrappedIMAP4(self.hostname, self.port, timeout=socket.getdefaulttimeout()) imapobj.mustquote = imaplibutil.mustquote if not self.tunnel: try: # Try GSSAPI and continue if it fails if 'AUTH=GSSAPI' in imapobj.capabilities and have_gss: self.connectionlock.acquire() self.ui.debug('imap', 'Attempting GSSAPI authentication') try: imapobj.authenticate('GSSAPI', self.gssauth) except imapobj.error, val: self.gssapi = False self.ui.debug('imap', 'GSSAPI Authentication failed') else: self.gssapi = True kerberos.authGSSClientClean(self.gss_vc) self.gss_vc = None self.gss_step = self.GSS_STATE_STEP #if we do self.password = None then the next attempt cannot try... #self.password = None self.connectionlock.release() if not self.gssapi: if 'AUTH=CRAM-MD5' in imapobj.capabilities: self.ui.debug('imap', 'Attempting CRAM-MD5 authentication') try: imapobj.authenticate('CRAM-MD5', self.md5handler) except imapobj.error, val: self.plainauth(imapobj) else: self.plainauth(imapobj) # Would bail by here if there was a failure. success = 1 self.goodpassword = self.password except imapobj.error, val: self.passworderror = str(val) raise #self.password = None if self.delim == None: listres = imapobj.list(self.reference, '""')[1] if listres == [None] or listres == None: # Some buggy IMAP servers do not respond well to LIST "" "" # Work around them. listres = imapobj.list(self.reference, '"*"')[1] if listres == [None] or listres == None: # No Folders were returned. This occurs, e.g. if the # 'reference' prefix does not exist on the mail # server. Raise exception. err = "Server '%s' returned no folders in '%s'" % \ (self.repos.getname(), self.reference) self.ui.warn(err) raise Exception(err) self.delim, self.root = \ imaputil.imapsplit(listres[0])[1:] self.delim = imaputil.dequote(self.delim) self.root = imaputil.dequote(self.root) self.connectionlock.acquire() self.assignedconnections.append(imapobj) self.lastowner[imapobj] = get_ident() self.connectionlock.release() return imapobj except Exception, e: """If we are here then we did not succeed in getting a connection - we should clean up and then re-raise the error...""" self.semaphore.release() #Make sure that this can be retried the next time... self.passworderror = None if(self.connectionlock.locked()): self.connectionlock.release() if type(e) == gaierror: #DNS related errors. Abort Repo sync severity = OfflineImapError.ERROR.REPO #TODO: special error msg for e.errno == 2 "Name or service not known"? reason = "Could not resolve name '%s' for repository "\ "'%s'. Make sure you have configured the ser"\ "ver name correctly and that you are online."%\ (self.hostname, self.reposname) raise OfflineImapError(reason, severity) elif SSLError and isinstance(e, SSLError) and e.errno == 1: # SSL unknown protocol error # happens e.g. when connecting via SSL to a non-SSL service if self.port != 443: reason = "Could not connect via SSL to host '%s' and non-s"\ "tandard ssl port %d configured. Make sure you connect"\ " to the correct port." % (self.hostname, self.port) else: reason = "Unknown SSL protocol connecting to host '%s' for"\ "repository '%s'. OpenSSL responded:\n%s"\ % (self.hostname, self.reposname, e) raise OfflineImapError(reason, severity) elif isinstance(e, socket.error) and e.args[0] == errno.ECONNREFUSED: # "Connection refused", can be a non-existing port, or an unauthorized # webproxy (open WLAN?) reason = "Connection to host '%s:%d' for repository '%s' was "\ "refused. Make sure you have the right host and port "\ "configured and that you are actually able to access the "\ "network." % (self.hostname, self.port, self.reposname) raise OfflineImapError(reason, severity) # Could not acquire connection to the remote; # socket.error(last_error) raised if str(e)[:24] == "can't open socket; error": raise OfflineImapError("Could not connect to remote server '%s' "\ "for repository '%s'. Remote does not answer." % (self.hostname, self.reposname), OfflineImapError.ERROR.REPO) else: # re-raise all other errors raise def connectionwait(self): """Waits until there is a connection available. Note that between the time that a connection becomes available and the time it is requested, another thread may have grabbed it. This function is mainly present as a way to avoid spawning thousands of threads to copy messages, then have them all wait for 3 available connections. It's OK if we have maxconnections + 1 or 2 threads, which is what this will help us do.""" self.semaphore.acquire() self.semaphore.release() def close(self): # Make sure I own all the semaphores. Let the threads finish # their stuff. This is a blocking method. self.connectionlock.acquire() threadutil.semaphorereset(self.semaphore, self.maxconnections) for imapobj in self.assignedconnections + self.availableconnections: imapobj.logout() self.assignedconnections = [] self.availableconnections = [] self.lastowner = {} # reset kerberos state self.gss_step = self.GSS_STATE_STEP self.gss_vc = None self.gssapi = False self.connectionlock.release() def keepalive(self, timeout, event): """Sends a NOOP to each connection recorded. It will wait a maximum of timeout seconds between doing this, and will continue to do so until the Event object as passed is true. This method is expected to be invoked in a separate thread, which should be join()'d after the event is set.""" self.ui.debug('imap', 'keepalive thread started') while 1: self.ui.debug('imap', 'keepalive: top of loop') if event.isSet(): self.ui.debug('imap', 'keepalive: event is set; exiting') return self.ui.debug('imap', 'keepalive: acquiring connectionlock') self.connectionlock.acquire() numconnections = len(self.assignedconnections) + \ len(self.availableconnections) self.connectionlock.release() self.ui.debug('imap', 'keepalive: connectionlock released') threads = [] for i in range(numconnections): self.ui.debug('imap', 'keepalive: processing connection %d of %d' % (i, numconnections)) if len(self.idlefolders) > i: idler = IdleThread(self, self.idlefolders[i]) else: idler = IdleThread(self) idler.start() threads.append(idler) self.ui.debug('imap', 'keepalive: thread started') self.ui.debug('imap', 'keepalive: waiting for timeout') event.wait(timeout) self.ui.debug('imap', 'keepalive: after wait') self.ui.debug('imap', 'keepalive: joining threads') for idler in threads: # Make sure all the commands have completed. idler.stop() idler.join() self.ui.debug('imap', 'keepalive: bottom of loop') class IdleThread(object): def __init__(self, parent, folder=None): self.parent = parent self.folder = folder self.event = Event() if folder is None: self.thread = Thread(target=self.noop) else: self.thread = Thread(target=self.idle) self.thread.setDaemon(1) def start(self): self.thread.start() def stop(self): self.event.set() def join(self): self.thread.join() def noop(self): imapobj = self.parent.acquireconnection() imapobj.noop() self.event.wait() self.parent.releaseconnection(imapobj) def dosync(self): remoterepos = self.parent.repos account = remoterepos.account localrepos = account.localrepos remoterepos = account.remoterepos statusrepos = account.statusrepos remotefolder = remoterepos.getfolder(self.folder) offlineimap.accounts.syncfolder(account.name, remoterepos, remotefolder, localrepos, statusrepos, quick=False) ui = getglobalui() ui.unregisterthread(currentThread()) def idle(self): while True: if self.event.isSet(): return self.needsync = False self.imapaborted = False def callback(args): result, cb_arg, exc_data = args if exc_data is None: if not self.event.isSet(): self.needsync = True self.event.set() else: # We got an "abort" signal. self.imapaborted = True self.stop() imapobj = self.parent.acquireconnection() imapobj.select(self.folder) if "IDLE" in imapobj.capabilities: imapobj.idle(callback=callback) else: ui = getglobalui() ui.warn("IMAP IDLE not supported on connection to %s." "Falling back to old behavior: sleeping until next" "refresh cycle." %(imapobj.identifier,)) imapobj.noop() self.event.wait() if self.event.isSet(): # Can't NOOP on a bad connection. if not self.imapaborted: imapobj.noop() # We don't do event.clear() so that we'll fall out # of the loop next time around. self.parent.releaseconnection(imapobj) if self.needsync: self.event.clear() self.dosync() class ConfigedIMAPServer(IMAPServer): """This class is designed for easier initialization given a ConfigParser object and an account name. The passwordhash is used if passwords for certain accounts are known. If the password for this account is listed, it will be obtained from there.""" def __init__(self, repository, passwordhash = {}): """Initialize the object. If the account is not a tunnel, the password is required.""" self.repos = repository self.config = self.repos.getconfig() usetunnel = self.repos.getpreauthtunnel() if not usetunnel: host = self.repos.gethost() user = self.repos.getuser() port = self.repos.getport() ssl = self.repos.getssl() sslclientcert = self.repos.getsslclientcert() sslclientkey = self.repos.getsslclientkey() sslcacertfile = self.repos.getsslcacertfile() reference = self.repos.getreference() idlefolders = self.repos.getidlefolders() server = None password = None if repository.getname() in passwordhash: password = passwordhash[repository.getname()] # Connect to the remote server. if usetunnel: IMAPServer.__init__(self, self.config, self.repos.getname(), tunnel = usetunnel, reference = reference, idlefolders = idlefolders, maxconnections = self.repos.getmaxconnections()) else: if not password: password = self.repos.getpassword() IMAPServer.__init__(self, self.config, self.repos.getname(), user, password, host, port, ssl, self.repos.getmaxconnections(), reference = reference, idlefolders = idlefolders, sslclientcert = sslclientcert, sslclientkey = sslclientkey, sslcacertfile = sslcacertfile)