# Copyright (c) 2009-2014 Upi Tamminen <desaster@gmail.com>
# See the COPYRIGHT file for more information

import os
import time
import fnmatch
import re
import stat
import errno

from config import config

A_NAME, \
    A_TYPE, \
    A_UID, \
    A_GID, \
    A_SIZE, \
    A_MODE, \
    A_CTIME, \
    A_CONTENTS, \
    A_TARGET, \
    A_REALFILE = range(0, 10)
T_LINK, \
    T_DIR, \
    T_FILE, \
    T_BLK, \
    T_CHR, \
    T_SOCK, \
    T_FIFO = range(0, 7)

class TooManyLevels(Exception):
    pass

class FileNotFound(Exception):
    pass

class HoneyPotFilesystem(object):
    def __init__(self, fs):
        self.fs = fs

        # keep count of new files, so we can have an artificial limit
        self.newcount = 0

    def resolve_path(self, path, cwd):
        pieces = path.rstrip('/').split('/')

        if path[0] == '/':
            cwd = []
        else:
            cwd = [x for x in cwd.split('/') if len(x) and x is not None]

        while 1:
            if not len(pieces):
                break
            piece = pieces.pop(0)
            if piece == '..':
                if len(cwd): cwd.pop()
                continue
            if piece in ('.', ''):
                continue
            cwd.append(piece)

        return '/%s' % '/'.join(cwd)

    def resolve_path_wc(self, path, cwd):
        pieces = path.rstrip('/').split('/')
        if len(pieces[0]):
            cwd = [x for x in cwd.split('/') if len(x) and x is not None]
            path = path[1:]
        else:
            cwd, pieces = [], pieces[1:]
        found = []
        def foo(p, cwd):
            if not len(p):
                found.append('/%s' % '/'.join(cwd))
            elif p[0] == '.':
                foo(p[1:], cwd)
            elif p[0] == '..':
                foo(p[1:], cwd[:-1])
            else:
                names = [x[A_NAME] for x in self.get_path('/'.join(cwd))]
                matches = [x for x in names if fnmatch.fnmatchcase(x, p[0])]
                for match in matches:
                    foo(p[1:], cwd + [match])
        foo(pieces, cwd)
        return found

    def get_path(self, path):
        cwd = self.fs
        for part in path.split('/'):
            if not len(part):
                continue
            ok = False
            for c in cwd[A_CONTENTS]:
                if c[A_NAME] == part:
                    cwd = c
                    ok = True
                    break
            if not ok:
               raise FileNotFound
        return cwd[A_CONTENTS]

    def exists(self, path):
        f = self.getfile(path)
        if f is not False:
            return True

    def update_realfile(self, f, realfile):
        if not f[A_REALFILE] and os.path.exists(realfile) and \
                not os.path.islink(realfile) and os.path.isfile(realfile) and \
                f[A_SIZE] < 25000000:
            #log.msg( 'Updating realfile to %s' % realfile )
            f[A_REALFILE] = realfile

    def realfile(self, f, path):
        self.update_realfile(f, path)
        if f[A_REALFILE]:
            return f[A_REALFILE]
        return None

    def getfile(self, path):
        if path == '/':
            return self.fs
        pieces = path.strip('/').split('/')
        p = self.fs
        while 1:
            if not len(pieces):
                break
            piece = pieces.pop(0)
            if piece not in [x[A_NAME] for x in p[A_CONTENTS]]:
                return False
            p = [x for x in p[A_CONTENTS] \
                if x[A_NAME] == piece][0]
        return p

    def file_contents(self, target, count = 0):
        if count > 10:
            raise TooManyLevels
        path = self.resolve_path(target, os.path.dirname(target))
        #log.msg( '%s resolved into %s' % (target, path) )
        if not path or not self.exists(path):
            raise FileNotFound
        f = self.getfile(path)
        if f[A_TYPE] == T_LINK:
            return self.file_contents(f[A_TARGET], count + 1)

        realfile = self.realfile(f, '%s/%s' % \
            (config().get('honeypot', 'contents_path'), path))
        if realfile:
            return file(realfile, 'rb').read()

    def mkfile(self, path, uid, gid, size, mode, ctime = None):
        if self.newcount > 10000:
            return False
        if ctime is None:
            ctime = time.time()
        dir = self.get_path(os.path.dirname(path))
        outfile = os.path.basename(path)
        if outfile in [x[A_NAME] for x in dir]:
            dir.remove([x for x in dir if x[A_NAME] == outfile][0])
        dir.append([outfile, T_FILE, uid, gid, size, mode, ctime, [],
            None, None])
        self.newcount += 1
        return True

    def mkdir(self, path, uid, gid, size, mode, ctime = None):
        if self.newcount > 10000:
            return False
        if ctime is None:
            ctime = time.time()
        if not len(path.strip('/')):
            return False
        try:
            dir = self.get_path(os.path.dirname(path.strip('/')))
        except IndexError:
            return False
        dir.append([os.path.basename(path), T_DIR, uid, gid, size, mode,
            ctime, [], None, None])
        self.newcount += 1
        return True

    def is_dir(self, path):
        if path == '/':
            return True
        try:
            dir = self.get_path(os.path.dirname(path))
        except: 
            dir = None
        if dir is None:
            return False
        l = [x for x in dir
            if x[A_NAME] == os.path.basename(path) and
            x[A_TYPE] == T_DIR]
        if l:
            return True
        return False

    # additions for SFTP support, try to keep functions here similar to os.*

    def open(self, filename, openFlags, mode):
        #log.msg( "fs.open %s" % filename )

        #if (openFlags & os.O_APPEND == os.O_APPEND):
        #    log.msg( "fs.open append" )

        #if (openFlags & os.O_CREAT == os.O_CREAT):
        #    log.msg( "fs.open creat" )

        #if (openFlags & os.O_TRUNC == os.O_TRUNC):
        #    log.msg( "fs.open trunc" )

        #if (openFlags & os.O_EXCL == os.O_EXCL):
        #    log.msg( "fs.open excl" )

        # treat O_RDWR same as O_WRONLY
        if openFlags & os.O_WRONLY == os.O_WRONLY or openFlags & os.O_RDWR == os.O_RDWR:
            # ensure we do not save with executable bit set
            realmode = mode & ~(stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)

            #log.msg( "fs.open wronly" )
            # TODO: safeoutfile could contains source IP address
            safeoutfile = '%s/%s_%s' % \
                       (config().get('honeypot', 'download_path'),
                    time.strftime('%Y%m%d%H%M%S'),
                    re.sub('[^A-Za-z0-9]', '_', filename))
            #log.msg( "fs.open file for writing, saving to %s" % safeoutfile )

            self.mkfile(filename, 0, 0, 0, stat.S_IFREG | mode)
            fd = os.open(safeoutfile, openFlags, realmode)
            self.update_realfile(self.getfile(filename), safeoutfile)

            return fd

        elif openFlags & os.O_RDONLY == os.O_RDONLY:
            return None

        return None

    # FIXME mkdir() name conflicts with existing mkdir
    def mkdir2(self, path):
        dir = self.getfile(path)
        if dir != False:
            raise OSError(errno.EEXIST, os.strerror(errno.EEXIST), path)
        return self.mkdir(path, 0, 0, 4096, 16877)

    def rmdir(self, path):
        raise notImplementedError

    def utime(self, path, atime, mtime):
        p = self.getfile(path)
        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        p[A_CTIME] = mtime

    def chmod(self, path, perm):
        p = self.getfile(path)
        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        p[A_MODE] = stat.S_IFMT(p[A_MODE]) | perm

    def chown(self, path, uid, gid):
        p = self.getfile(path)
        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        if (uid != -1):
            p[A_UID] = uid
        if (gid != -1):
            p[A_GID] = gid

    def remove(self, path):
        p = self.getfile(path)
        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        self.get_path(os.path.dirname(path)).remove(p)
        return

    def readlink(self, path):
        p = self.getfile(path)
        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        if not (p[A_MODE] & stat.S_IFLNK):
            raise OSError
        return p[A_TARGET]

    def symlink(self, targetPath, linkPath):
        raise notImplementedError

    def rename(self, oldpath, newpath):
        #log.msg( "rename %s to %s" % (oldpath, newpath) )
        old = self.getfile(oldpath)
        if old == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))
        new = self.getfile(newpath)
        if new != False:
            raise OSError(errno.EEXIST, os.strerror(errno.EEXIST))

        self.get_path(os.path.dirname(oldpath)).remove(old)
        old[A_NAME] = os.path.basename(newpath)
        self.get_path(os.path.dirname(newpath)).append(old)
        return

    def read(self, fd, size):
        # this should not be called, we intercept at readChunk
        raise notImplementedError

    def write(self, fd, string):
        return os.write(fd, string)

    def close(self, fd):
        if (fd == None):
            return True
        return os.close(fd)

    def lseek(self, fd, offset, whence):
        if (fd == None):
            return True
        return os.lseek(fd, offset, whence)

    def listdir(self, path):
        names = [x[A_NAME] for x in self.get_path(path)]
        return names

    def lstat(self, path):

        # need to treat / as exception
        if (path == "/"):
            p = { A_TYPE:T_DIR, A_UID:0, A_GID:0, A_SIZE:4096, A_MODE:16877, A_CTIME:time.time() }
        else:
            p = self.getfile(path)

        if p == False:
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))

        return _statobj(
               p[A_MODE],
         0,
         0,
         1,
         p[A_UID],
         p[A_GID],
         p[A_SIZE],
         p[A_CTIME],
         p[A_CTIME],
         p[A_CTIME])

    def stat(self, path):
        if (path == "/"):
            p = { A_TYPE:T_DIR, A_UID:0, A_GID:0, A_SIZE:4096, A_MODE:16877, A_CTIME:time.time() }
        else:
            p = self.getfile(path)

        if (p == False):
            raise OSError(errno.ENOENT, os.strerror(errno.ENOENT))

        #if p[A_MODE] & stat.S_IFLNK == stat.S_IFLNK:
        if p[A_TYPE] == T_LINK:
            return self.stat(p[A_TARGET])

        return self.lstat(path)

    def realpath(self, path):
        return path

    def update_size(self, filename, size):
        f = self.getfile(filename)
        if (f == False):
            return
        if (f[A_TYPE] != T_FILE):
            return
        f[A_SIZE] = size


# transform a tuple into a stat object
class _statobj:
    def __init__(self, st_mode, st_ino, st_dev, st_nlink, st_uid, st_gid, st_size, st_atime, st_mtime, st_ctime):
        self.st_mode = st_mode
        self.st_ino = st_ino
        self.st_dev = st_dev
        self.st_nlink = st_nlink
        self.st_uid = st_uid
        self.st_gid = st_gid
        self.st_size = st_size
        self.st_atime = st_atime
        self.st_mtime = st_mtime
        self.st_ctime = st_ctime

# vim: set sw=4 et: