crypto-exmlm: added python interface

crypto-ezmlm/trunk/python/lispet/interfaces/ezmlm.py

@@ -0,0 +1,162 @@
+#!/usr/bin/env python2.4
+#
+# This file is part of lispet - an encryption filter for different
+# mailing list manager.
+#
+# Copyright 02007-02008 Sense.Lab e.V. <info@senselab.org>
+#
+#
+# lispet 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.
+# 
+# lispet 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 the CryptoBox; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+#
+
+
+
+import sys
+import os
+import re
+# the following modules are imported later
+#import subprocess
+
+# check if the subprocess module is available (python >= 2.4)
+try:
+	import subprocess
+except ImportError:
+	sys.stderr.write("Failed to import the python module 'subprocess'! "
+			. "It requires python2.4 or higher.\n")
+	sys.exit(1)
+
+
+############### some default settings ##################
+
+## we will finally deliver via the original qmail-queue
+if os.environ.has_key("QMAILQUEUE"):
+	QMAILQUEUE_BIN = os.environ["QMAILQUEUE"]
+else:
+	QMAILQUEUE_BIN = '/var/qmail/bin/qmail-queue'
+
+
+
+def write_to_qmailqueue:
+		## use tmpfile as input for qmail-queue
+		## we have to complicate things a little bit, as qmail-queue expects input
+		## at file handle 1 - this is usually stdout
+		# TODO: use something like StringIO instead
+		tmpfile = os.tmpfile()
+		tmpfile.write('F%s\0T%s\0\0' % (sender, recipient))
+		tmpfile.seek(0)
+		## execute the original qmail-queue
+		proc = subprocess.Popen(
+			shell = False,
+			stdin = subprocess.PIPE,
+			stdout = tmpfile.fileno(),
+			env = os.environ,
+			args = [ QMAILQUEUE_BIN ] )
+		proc.stdin.write(mail.as_string())
+		## tmpfile is deleted automatically after closing
+		tmpfile.close()
+		proc.stdin.close()
+		proc.wait()
+		## exit immediately, if qmail-queue failed once
+		if proc.returncode != 0:
+			sys.exit(proc.returncode)
+
+
+
+#################### input/output stuff ###################
+
+def internal_error(message=None, exitcode=81):
+	if message:
+		sys.stderr.write(message + "\n")
+	sys.exit(exitcode)
+
+
+def process_input_and_output(handler):
+	"""Read mail content and the envelopement information from fd1 and fd2
+
+	see 'main qmail-queue' for details
+	"""
+	in_mail = os.fdopen(0, "r")
+	in_envelope = os.fdopen(1, "rb")
+	## try to read mail and 
+	try:
+		mail_text = in_mail.read()
+		envelope = in_envelope.read()
+	except IOError:
+		## report "Unable to read the message or envelope." (see 'man qmail-queue')
+		sys.exit(54)
+	## see 'man qmail-queue' for details of the envelope format
+	envelope_addresses = re.match(u'F(.+?)\0((?:T[^\0]+?\0)+)\0$', envelope)
+	if not envelope_addresses or (len(envelope_addresses.groups()) != 2):
+		## report "Envelope format error." (see 'man qmail-queue')
+		sys.exit(91)
+	## the first match is the sender address
+	envelope_sender = envelope_addresses.groups()[0]
+	## the second match is the list of all recipients
+	## each preceded by "T" and followed by "\0"
+	envelope_recipients = envelope_addresses.groups()[1].split("\0")
+	## remove leading "T" and skip empty values
+	envelope_recipients = [ e[1:] for e in envelope_recipients if e ]
+	for recipient in envelope_recipients:
+		handler.process_mail(envelope_sender, recipient, mail_text)
+
+
+def check_for_errors():
+	errors = False
+	## check the original qmail-queue binary
+	if not os.access(QMAILQUEUE_BIN, os.X_OK):
+		sys.stderr.write("Could not find executable qmail-queue: %s\n" % QMAILQUEUE_BIN)
+		errors = True
+	## check the existence of the pyme module
+	try:
+		import pyme
+	except ImportError:
+		sys.stderr.write("Failed to import python-pyme!\n")
+		errors = True
+	## check if the subprocess module is available (python >= 2.4)
+	try:
+		import subprocess
+	except ImportError:
+		sys.stderr.write("Failed to import the python module 'subprocess'! It requires python2.4.\n")
+		errors = True
+	return errors == False
+
+
+if __name__ == '__main__':
+	# reduce priority
+	os.nice(5)
+	if not check_for_errors():
+		internal_error()
+	if len(sys.argv) == 1:
+		## we were only supposed to run the self-tests - exiting successfully
+		sys.exit(0)
+	## we expect exactly one parameter - the mailinglist directory
+	if len(sys.argv) != 2:
+		internal_error("More than one parameter (the mailinglist directory) given!")
+	## print some help if it was requested
+	if sys.argv[0] == '--help':
+		sys.stderr.write("Syntax: %s [MAILINGLIST_DIRECTORY]\n\n" % \
+				os.path.basename(sys.argv[0]))
+		sys.stderr.write("If you omit the MAILINGLIST_DIRECTORY, " \
+				+ "then only some self-tests are done.\n\n")
+		sys.exit(0)
+	## retrieve the mailing list directory by reading the dotqmail file
+	list_dir = sys.argv[1]
+	## does the mailinglist directory exist?
+	if not os.access(list_dir, os.X_OK):
+		internal_error("Could not access the mailinglist directory: %s" % list_dir)
+	## reencrypt the mail for each recipient
+	mail_handler = MailEncryption(list_dir)
+	process_input_and_output(mail_handler)
+