# 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 import imaplib from offlineimap import imaplibutil, imaputil, threadutil from offlineimap.ui import UIBase from threading import * import thread, hmac, os, time import base64 from StringIO import StringIO from platform import system try: # do we have a recent pykerberos? have_gss = False import kerberos if 'authGSSClientWrap' in dir(kerberos): have_gss = True except ImportError: pass class UsefulIMAPMixIn: def getstate(self): return self.state def getselectedfolder(self): if self.getstate() == 'SELECTED': return self.selectedfolder return None def select(self, mailbox='INBOX', readonly=None, force = 0): if (not force) and self.getselectedfolder() == mailbox \ and self.is_readonly == readonly: # No change; return. return result = self.__class__.__bases__[1].select(self, mailbox, readonly) if result[0] != 'OK': raise ValueError, "Error from select: %s" % str(result) if self.getstate() == 'SELECTED': self.selectedfolder = mailbox else: self.selectedfolder = None def _mesg(self, s, secs=None): imaplibutil.new_mesg(self, s, secs) class UsefulIMAP4(UsefulIMAPMixIn, imaplib.IMAP4): def open(self, host = '', port = imaplib.IMAP4_PORT): imaplibutil.new_open(self, host, port) # This is a hack around Darwin's implementation of realloc() (which # Python uses inside the socket code). On Darwin, we split the # message into 100k chunks, which should be small enough - smaller # might start seriously hurting performance ... def read(self, size): if (system() == 'Darwin') and (size>0) : read = 0 io = StringIO() while read < size: data = imaplib.IMAP4.read (self, min(size-read,8192)) read += len(data) io.write(data) return io.getvalue() else: return imaplib.IMAP4.read (self, size) class UsefulIMAP4_SSL(UsefulIMAPMixIn, imaplibutil.WrappedIMAP4_SSL): def open(self, host = '', port = imaplib.IMAP4_SSL_PORT): imaplibutil.new_open_ssl(self, host, port) # This is the same hack as above, to be used in the case of an SSL # connexion. def read(self, size): if (system() == 'Darwin') and (size>0) : read = 0 io = StringIO() while read < size: data = imaplibutil.WrappedIMAP4_SSL.read (self, min(size-read,8192)) read += len(data) io.write(data) return io.getvalue() else: return imaplibutil.WrappedIMAP4_SSL.read (self,size) class UsefulIMAP4_Tunnel(UsefulIMAPMixIn, imaplibutil.IMAP4_Tunnel): 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): 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.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.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 = UIBase.getglobalui().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) self.availableconnections.append(connection) self.connectionlock.release() self.semaphore.release() def md5handler(self, response): ui = UIBase.getglobalui() challenge = response.strip() ui.debug('imap', 'md5handler: got challenge %s' % challenge) passwd = self.getpassword() retval = self.username + ' ' + hmac.new(passwd, challenge).hexdigest() ui.debug('imap', 'md5handler: returning %s' % retval) return retval def plainauth(self, imapobj): UIBase.getglobalui().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 UIBase.getglobalui().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. threadid = thread.get_ident() imapobj = None for i in range(len(self.availableconnections) - 1, -1, -1): tryobj = self.availableconnections[i] if self.lastowner[tryobj] == threadid: 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] = thread.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: UIBase.getglobalui().connecting('tunnel', self.tunnel) imapobj = UsefulIMAP4_Tunnel(self.tunnel) success = 1 elif self.usessl: UIBase.getglobalui().connecting(self.hostname, self.port) imapobj = UsefulIMAP4_SSL(self.hostname, self.port, self.sslclientkey, self.sslclientcert) else: UIBase.getglobalui().connecting(self.hostname, self.port) imapobj = UsefulIMAP4(self.hostname, self.port) 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: UIBase.getglobalui().debug('imap', 'Attempting GSSAPI authentication') try: imapobj.authenticate('GSSAPI', self.gssauth) except imapobj.error, val: self.gssapi = False UIBase.getglobalui().debug('imap', 'GSSAPI Authentication failed') else: self.gssapi = True #if we do self.password = None then the next attempt cannot try... #self.password = None if not self.gssapi: if 'AUTH=CRAM-MD5' in imapobj.capabilities: UIBase.getglobalui().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] 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] = thread.get_ident() self.connectionlock.release() return imapobj except: """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() 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.""" threadutil.semaphorewait(self.semaphore) 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.""" ui = UIBase.getglobalui() ui.debug('imap', 'keepalive thread started') while 1: ui.debug('imap', 'keepalive: top of loop') time.sleep(timeout) ui.debug('imap', 'keepalive: after wait') if event.isSet(): ui.debug('imap', 'keepalive: event is set; exiting') return ui.debug('imap', 'keepalive: acquiring connectionlock') self.connectionlock.acquire() numconnections = len(self.assignedconnections) + \ len(self.availableconnections) self.connectionlock.release() ui.debug('imap', 'keepalive: connectionlock released') threads = [] imapobjs = [] for i in range(numconnections): ui.debug('imap', 'keepalive: processing connection %d of %d' % (i, numconnections)) imapobj = self.acquireconnection() ui.debug('imap', 'keepalive: connection %d acquired' % i) imapobjs.append(imapobj) thr = threadutil.ExitNotifyThread(target = imapobj.noop) thr.setDaemon(1) thr.start() threads.append(thr) ui.debug('imap', 'keepalive: thread started') ui.debug('imap', 'keepalive: joining threads') for thr in threads: # Make sure all the commands have completed. thr.join() ui.debug('imap', 'keepalive: releasing connections') for imapobj in imapobjs: self.releaseconnection(imapobj) ui.debug('imap', 'keepalive: bottom of loop') 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() reference = self.repos.getreference() 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, 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, sslclientcert = sslclientcert, sslclientkey = sslclientkey)