#! /usr/bin/env python
# -*- coding: ISO-8859-15 -*-

# An email gateway for PyKota
#
# PyKota - Print Quotas for CUPS and LPRng
#
# (c) 2003, 2004, 2005, 2006, 2007 Jerome Alet <alet@librelogiciel.com>
# 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 Street, Fifth Floor, Boston, MA 02110-1301, USA.
#
# $Id: pkmail 3137 2007-01-18 18:21:26Z jerome $
#
#

import sys
import os
import popen2
import smtplib
import email
from email.MIMEText import MIMEText
from email.Header import Header
import email.Utils

from pykota.tool import PyKotaTool, PyKotaCommandLineError, crashed, N_
    
__doc__ = N_("""pkmail v%(__version__)s (c) %(__years__)s %(__author__)s

Email gateway for PyKota.

command line usage :

  pkmail  [options]

options :

  -v | --version       Prints pkmail's version number then exits.
  -h | --help          Prints this message then exits.
  
    
  This command is meant to be used from your mail server's aliases file,
  as a pipe. It will then accept commands send to it in email messages,
  and will send the answer to the command's originator.
  
  To use this command, create an email alias in /etc/aliases with
  the following format :
  
    pykotacmd: "|/usr/bin/pkmail"
    
  Then run the 'newaliases' command to regenerate the aliases database.
  
  You can now send commands by email to 'pykotacmd@yourdomain.com', with
  the command in the subject.
  
  List of supported commands :
  
        report [username]
  
  NB : For pkmail to work correctly, you may have to put the 'mail'
  system user in the 'pykota' system group to ensure this user can
  read the /etc/pykota/pykotadmin.conf file, and restart your
  mail server (e.g. /etc/init.d/exim restart). It is strongly advised
  that you think at least twice before doing this though.
  
  Use at your own risk !
""")
        
        
class PKMail(PyKotaTool) :        
    """A class for pkmail."""
    def main(self, files, options) :
        """Accepts commands passed in an email message."""
        data = sys.stdin.read()
        message = email.message_from_string(data)
        useremail = message["From"]
        whoami = message["To"]
        cmdargs = message["Subject"].split()
        try :
            (command, arguments) = (cmdargs[0].capitalize(), cmdargs[1:])
        except IndexError :    
            raise PyKotaCommandLineError, "No command found !"
        
        badchars = """/<>&"'#!%*$,;\\"""
        cheatmeonce = 0
        for c in "".join(arguments) :
            if c in badchars :
                cheatmeonce = 1
            
        if cheatmeonce :    
            self.printInfo("Possible intruder at %s : %s" % (useremail, str(arguments)), "warn")
            result = "Either you mistyped your command, or you're a bad guy !"
        else :
            self.logdebug("Launching internal command '%s' with arguments %s" % (command, str(arguments)))
            cmdfunc = getattr(self, "cmd%s" % command, self.cmdDefault)
            result = cmdfunc(arguments)
        
        self.logdebug("Sending answer to : %s" % useremail)
        emailmsg = MIMEText(result, _charset=self.charset)
        emailmsg["Subject"] = Header(_("Result of your commands"), charset=self.charset)
        emailmsg["From"] = whoami
        emailmsg["To"] = useremail
        emailmsg["Date"] = email.Utils.formatdate(localtime=True)
        server = smtplib.SMTP(self.smtpserver)
        server.sendmail(whoami, [ useremail ], emailmsg.as_string())
        server.quit()
        self.logdebug("Answer sent to : %s" % useremail)
        
        return 0
        
    def runCommand(self, cmd) :    
        """Executes a command."""
        self.logdebug("Launching : '%s'" % cmd)
        os.environ["PATH"] = "%s:/bin:/usr/bin:/usr/local/bin:/opt/bin:/sbin:/usr/sbin" % os.environ.get("PATH", "")
        child = popen2.Popen3(cmd)
        child.tochild.close()
        result = child.fromchild.read()
        status = child.wait()
        if os.WIFEXITED(status) :
            status = os.WEXITSTATUS(status)
        self.logdebug("'%s' exited with status %s" % (cmd, status))
        return result
        
    def cmdDefault(self, arguments) :    
        """Default command : sends an 'unknown command' message."""
        return "Unknown command."
        
    def cmdReport(self, args) :    
        """Generates a print quota report."""
        return self.runCommand("repykota %s" % ' '.join([ '"%s"' % a for a in args ]))
            
if __name__ == "__main__" : 
    retcode = 0
    try :
        defaults = { \
                   }
        short_options = "vh"
        long_options = ["help", "version"]
        
        # Initializes the command line tool
        mailparser = PKMail(doc=__doc__)
        mailparser.deferredInit()
        
        # parse and checks the command line
        (options, args) = mailparser.parseCommandline(sys.argv[1:], short_options, long_options, allownothing=1)
        
        # sets long options
        options["help"] = options["h"] or options["help"]
        options["version"] = options["v"] or options["version"]
        
        if options["help"] :
            mailparser.display_usage_and_quit()
        elif options["version"] :
            mailparser.display_version_and_quit()
        else :
            retcode = mailparser.main(args, options)
    except KeyboardInterrupt :        
        sys.stderr.write("\nInterrupted with Ctrl+C !\n")
        retcode = -3
    except PyKotaCommandLineError, msg :    
        sys.stderr.write("%s : %s\n" % (sys.argv[0], msg))
        retcode = -2
    except SystemExit :        
        pass
    except :
        try :
            mailparser.crashed("pkmail failed")
        except :    
            crashed("pkmail failed")
        retcode = -1

    try :
        mailparser.storage.close()
    except (TypeError, NameError, AttributeError) :    
        pass
        
    sys.exit(retcode)