# Copyright (C) 1998-2003 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. """ Track pending confirmation of subscriptions. new(stuff...) places an item's data in the db, returning its cookie. confirmed(cookie) returns a tuple for the data, removing the item from the db. It returns None if the cookie is not registered. """ import os import time import sha import marshal import cPickle import random import errno from Mailman import mm_cfg from Mailman import LockFile DBFILE = os.path.join(mm_cfg.DATA_DIR, 'pending.db') PCKFILE = os.path.join(mm_cfg.DATA_DIR, 'pending.pck') LOCKFILE = os.path.join(mm_cfg.LOCK_DIR, 'pending.lock') # Types of pending records SUBSCRIPTION = 'S' UNSUBSCRIPTION = 'U' CHANGE_OF_ADDRESS = 'C' HELD_MESSAGE = 'H' RE_ENABLE = 'E' _ALLKEYS = [(x,) for x in (SUBSCRIPTION, UNSUBSCRIPTION, CHANGE_OF_ADDRESS, HELD_MESSAGE, RE_ENABLE, )] try: True, False except NameError: True = 1 False = 0 def new(*content): """Create a new entry in the pending database, returning cookie for it.""" # It's a programming error if this assertion fails! We do it this way so # the assert test won't fail if the sequence is empty. assert content[:1] in _ALLKEYS # Get a lock handle now, but only lock inside the loop. lock = LockFile.LockFile(LOCKFILE, withlogging=mm_cfg.PENDINGDB_LOCK_DEBUGGING) # We try the main loop several times. If we get a lock error somewhere # (for instance because someone broke the lock) we simply try again. retries = mm_cfg.PENDINGDB_LOCK_ATTEMPTS try: while retries: retries -= 1 if not lock.locked(): try: lock.lock(timeout=mm_cfg.PENDINGDB_LOCK_TIMEOUT) except LockFile.TimeOutError: continue # Load the current database db = _load() # Calculate a unique cookie. Algorithm vetted by the Timbot. # time() has high resolution on Linux, clock() on Windows. random # gives us about 45 bits in Python 2.2, 53 bits on Python 2.3. # The time and clock values basically help obscure the random # number generator, as does the hash calculation. The integral # parts of the time values are discarded because they're the most # predictable bits. while True: now = time.time() x = random.random() + now % 1.0 + time.clock() % 1.0 hashfood = repr(x) cookie = sha.new(hashfood).hexdigest() # We'll never get a duplicate, but we'll be anal about # checking anyway. if not db.has_key(cookie): break # Store the content, plus the time in the future when this entry # will be evicted from the database, due to staleness. db[cookie] = content evictions = db.setdefault('evictions', {}) evictions[cookie] = now + mm_cfg.PENDING_REQUEST_LIFE try: _save(db, lock) except LockFile.NotLockedError: continue return cookie else: # We failed to get the lock or keep it long enough to save the # data! raise LockFile.TimeOutError finally: if lock.locked(): lock.unlock() def confirm(cookie, expunge=True): """Return data for cookie, or None if not found. If optional expunge is True (the default), the record is also removed from the database. """ if not expunge: db = _load() missing = [] content = db.get(cookie, missing) if content is missing: return None return content # Get a lock handle now, but only lock inside the loop. lock = LockFile.LockFile(LOCKFILE, withlogging=mm_cfg.PENDINGDB_LOCK_DEBUGGING) # We try the main loop several times. If we get a lock error somewhere # (for instance because someone broke the lock) we simply try again. retries = mm_cfg.PENDINGDB_LOCK_ATTEMPTS try: while retries: retries -= 1 if not lock.locked(): try: lock.lock(timeout=mm_cfg.PENDINGDB_LOCK_TIMEOUT) except LockFile.TimeOutError: continue # Load the database db = _load() missing = [] content = db.get(cookie, missing) if content is missing: return None del db[cookie] del db['evictions'][cookie] try: _save(db, lock) except LockFile.NotLockedError: continue return content else: # We failed to get the lock and keep it long enough to save the # data! raise LockFile.TimeOutError finally: if lock.locked(): lock.unlock() def _load(): # The list's lock must be acquired if you wish to alter data and save. # # First try to load the pickle file fp = None try: try: fp = open(PCKFILE) return cPickle.load(fp) except IOError, e: if e.errno <> errno.ENOENT: raise try: # Try to load the old DBFILE fp = open(DBFILE) return marshal.load(fp) except IOError, e: if e.errno <> errno.ENOENT: raise # Fresh pendings database return {'evictions': {}} finally: if fp: fp.close() def _save(db, lock): # Lock must be acquired before loading the data that is now being saved. if not lock.locked(): raise LockFile.NotLockedError evictions = db['evictions'] now = time.time() for cookie, data in db.items(): if cookie in ('evictions', 'version'): continue timestamp = evictions[cookie] if now > timestamp: # The entry is stale, so remove it. del db[cookie] del evictions[cookie] # Clean out any bogus eviction entries. for cookie in evictions.keys(): if not db.has_key(cookie): del evictions[cookie] db['version'] = mm_cfg.PENDING_FILE_SCHEMA_VERSION omask = os.umask(007) # Always save this as a pickle (safely), and after that succeeds, blow # away any old marshal file. tmpfile = '%s.tmp.%d.%d' % (PCKFILE, os.getpid(), now) fp = None try: fp = open(tmpfile, 'w') cPickle.dump(db, fp) fp.close() fp = None if not lock.locked(): # Our lock was broken? os.remove(tmpfile) raise LockFile.NotLockedError os.rename(tmpfile, PCKFILE) if os.path.exists(DBFILE): os.remove(DBFILE) finally: if fp: fp.close() os.umask(omask) def _update(olddb): # Update an old pending_subscriptions.db database to the new format lock = LockFile.LockFile(LOCKFILE, withlogging=mm_cfg.PENDINGDB_LOCK_DEBUGGING) lock.lock(timeout=mm_cfg.PENDINGDB_LOCK_TIMEOUT) try: # We don't need this entry anymore if olddb.has_key('lastculltime'): del olddb['lastculltime'] db = _load() evictions = db.setdefault('evictions', {}) for cookie, data in olddb.items(): # The cookies used to be kept as a 6 digit integer. We now keep # the cookies as a string (sha in our case, but it doesn't matter # for cookie matching). cookie = str(cookie) # The old format kept the content as a tuple and tacked the # timestamp on as the last element of the tuple. We keep the # timestamps separate, but require the prepending of a record type # indicator. We know that the only things that were kept in the # old format were subscription requests. Also, the old request # format didn't have the subscription language. Best we can do # here is use the server default. db[cookie] = (SUBSCRIPTION,) + data[:-1] + \ (mm_cfg.DEFAULT_SERVER_LANGUAGE,) # The old database format kept the timestamp as the time the # request was made. The new format keeps it as the time the # request should be evicted. evictions[cookie] = data[-1] + mm_cfg.PENDING_REQUEST_LIFE _save(db, lock) finally: if lock.locked(): lock.unlock()