scripts/x

Mon, 13 Nov 2006 23:06:30 -0500

author
brett
date
Mon, 13 Nov 2006 23:06:30 -0500
branch
trunk
changeset 8
97388f5ff770
parent 7
1f3cb3845dfd
child 9
920417b8acc9
permissions
-rwxr-xr-x

[svn] Make ExtractorApplication suck less. Now the strategies for handling
different archive types are out in their own classes, and polymorphism
takes care of everything for us. This is way cleaner.

While I was at it I changed the behavior in the case where an archive
contains one directory that doesn't match the basename. I now treat that
the same as a bomb. This can lead to silly directory structures but
ensures that there's no "data" loss nor unexpected results.

#!/usr/bin/env python
#
# x -- Intelligently extract various archive types.
# Copyright (c) 2006 Brett Smith <brettcsmith@brettcsmith.org>.
#
# 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, 5th Floor, Boston, MA, 02111.

import errno
import mimetypes
import optparse
import os
import subprocess
import sys
import tempfile

from cStringIO import StringIO

VERSION = "1.1"
VERSION_BANNER = """x version %s
Copyright (c) 2006 Brett Smith <brettcsmith@brettcsmith.org>

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.""" % (VERSION,)

MATCHING_DIRECTORY = 1
# ONE_DIRECTORY = 2
BOMB = 3
EMPTY = 4

mimetypes.encodings_map.setdefault('.bz2', 'bzip2')
mimetypes.types_map['.exe'] = 'application/x-msdos-program'

class ExtractorError(Exception):
    pass


class ProcessStreamer(object):
    def __init__(self, command, stdin, description="checking contents",
                 stderr=None):
        self.process = subprocess.Popen(command, bufsize=1, stdin=stdin,
                                        stdout=subprocess.PIPE, stderr=stderr)
        self.command = ' '.join(command)
        self.description = description

    def __iter__(self):
        return self

    def next(self):
        line = self.process.stdout.readline()
        if line:
            return line.rstrip('\n')
        else:
            raise StopIteration

    def stop(self):
        while self.process.stdout.readline():
            pass
        self.process.stdout.close()
        status = self.process.wait()
        if status != 0:
            raise ExtractorError("%s error: '%s' returned status code %s" %
                                 (self.description, self.command, status))
        try:
            self.process.stderr.close()
        except AttributeError:
            pass
    

class BaseExtractor(object):
    decoders = {'bzip2': 'bzcat', 'gzip': 'zcat', 'compress': 'zcat'}

    def __init__(self, filename, mimetype, encoding):
        if encoding and (not self.decoders.has_key(encoding)):
            raise ValueError("unrecognized encoding %s" % (encoding,))
        self.filename = filename
        self.mimetype = mimetype
        self.encoding = encoding
        self.included_archives = []
        try:
            self.archive = open(filename, 'r')
        except (IOError, OSError), error:
            raise ExtractorError("could not open %s: %s" %
                                 (filename, error.strerror))
        if encoding:
            self.pipe([self.decoders[encoding]], "decoding")
        self.prepare()

    def run(self, command, description="extraction", stdout=None, stderr=None,
            stdin=None):
        process = subprocess.Popen(command, stdin=stdin, stdout=stdout,
                                   stderr=stderr)
        status = process.wait()
        if status != 0:
            raise ExtractorError("%s error: '%s' returned status code %s" %
                                 (description, ' '.join(command), status))
        for pipe in (process.stdout, process.stderr):
            try:
                pipe.close()
            except AttributeError:
                pass

    def pipe(self, command, description, stderr=None):
        output = tempfile.TemporaryFile()
        self.run(command, description, output, stderr, self.archive)
        self.archive.close()
        self.archive = output
        self.archive.flush()
    
    def prepare(self):
        pass

    def check_contents(self):
        self.archive.seek(0, 0)
        archive_type = None
        filenames = self.get_filenames()
        try:
            filename = filenames.next()
            if extractor_map.has_key(mimetypes.guess_type(filename)[0]):
                self.included_archives.append(filename)
            first_part = filename.split('/', 1)[0] + '/'
        except StopIteration:
            filenames.stop()
            return EMPTY
        for filename in filenames:
            if extractor_map.has_key(mimetypes.guess_type(filename)[0]):
                self.included_archives.append(filename)
            if (archive_type is None) and (not filename.startswith(first_part)):
                archive_type = BOMB
        filenames.stop()
        if archive_type:
            return archive_type
        if self.basename() == first_part[:-1]:
            return MATCHING_DIRECTORY
        return first_part

    def basename(self):
        pieces = os.path.basename(self.filename).split('.')
        extension = '.' + pieces[-1]
        if mimetypes.encodings_map.has_key(extension):
            pieces.pop()
            extension = '.' + pieces[-1]
        if (mimetypes.types_map.has_key(extension) or
            mimetypes.common_types.has_key(extension) or
            mimetypes.suffix_map.has_key(extension)):
            pieces.pop()
        return '.'.join(pieces)

    def extract(self, path):
        self.archive.seek(0, 0)
        self.extract_archive()
    

class TarExtractor(BaseExtractor):
    def get_filenames(self):
        return ProcessStreamer(['tar', '-t'], self.archive)

    def extract_archive(self):
        self.run(['tar', '-x'], stdin=self.archive)
        
        
class ZipExtractor(BaseExtractor):
    def __init__(self, filename, mimetype, encoding):
        self.filename = filename
        self.mimetype = mimetype
        self.encoding = encoding
        self.included_archives = []
        self.archive = StringIO()

    def get_filenames(self):
        return ProcessStreamer(['zipinfo', '-1', self.filename], None)

    def extract(self, path):
        self.run(['unzip', '-q', os.path.join(path, self.filename)])


class CpioExtractor(BaseExtractor):
    def get_filenames(self):
        return ProcessStreamer(['cpio', '-t'], self.archive,
                               stderr=subprocess.PIPE)

    def extract_archive(self):
        self.run(['cpio', '-i', '--make-directories',
                  '--no-absolute-filenames'],
                 stderr=subprocess.PIPE, stdin=self.archive)


class RPMExtractor(CpioExtractor):
    def prepare(self):
        self.pipe(['rpm2cpio', '-'], "rpm2cpio")

    def basename(self):
        pieces = os.path.basename(self.filename).rsplit('.', 2)
        if len(pieces) == 1:
            return pieces[0]
        elif pieces[-1] != 'rpm':
            return BaseExtractor.basename(self)
        pieces.pop()
        if len(pieces) == 1:
            return pieces[0]
        elif len(pieces[-1]) < 6:
            pieces.pop()
        return '.'.join(pieces)

    def check_contents(self):
        CpioExtractor.check_contents(self)
        return BOMB


class DebExtractor(TarExtractor):
    def prepare(self):
        self.pipe(['ar', 'p', self.filename, 'data.tar.gz'],
                  "data.tar.gz extraction")
        self.archive.seek(0, 0)
        self.pipe(['zcat'], "data.tar.gz decompression")

    def basename(self):
        pieces = os.path.basename(self.filename).rsplit('_', 1)
        if len(pieces) == 1:
            return pieces[0]
        elif (len(pieces[-1]) > 10) or (not pieces[-1].endswith('.deb')):
            return BaseExtractor.basename(self)
        return pieces[0]

    def check_contents(self):
        TarExtractor.check_contents(self)
        return BOMB
        

class MatchHandler(object):
    def __init__(self, extractor, contents):
        self.extractor = extractor
        self.contents = contents
        self.directory = extractor.basename()

    def extract(self, directory='.'):
        try:
            self.extractor.extract(directory)
        except ExtractorError, error:
            return error.strerror

    def cleanup(self):
        command = 'chmod'
        status = subprocess.call(['chmod', '-R', 'u+rw', self.directory])
        if status == 0:
            command = 'find'
            status = subprocess.call(['find', self.directory, '-type', 'd',
                                      '-exec', 'chmod', 'u+x', '{}', ';'])
        if status != 0:
            return "%s returned with exit status %s" % (command, status)
        
        
class BombHandler(MatchHandler):
    def __init__(self, extractor, contents):
        MatchHandler.__init__(self, extractor, contents)
        basename = self.directory
        for suffix in [''] + ['.%s' % (x,) for x in range(1, 10)]:
            self.directory = '%s%s' % (basename, suffix)
            try:
                os.mkdir(self.directory)
            except OSError, error:
                if error.errno == errno.EEXIST:
                    continue
                raise ValueError("could not make extraction directory %s: %s" %
                                 (error.filename, error.strerror))
##             if suffix != '':
##                 self.show_error("extracted to %s" % (directory,))
            break
        else:
            raise ValueError("all good names for an extraction directory taken")

    def extract(self):
        os.chdir(self.directory)
        return MatchHandler.extract(self, '..')

    def cleanup(self):
        os.chdir('..')
        return MatchHandler.cleanup(self)
        

class EmptyHandler(object):
    def __init__(self, extractor, contents): pass
    def extract(self): pass
    def cleanup(self): pass

extractor_map = {'application/x-tar': TarExtractor,
                 'application/zip': ZipExtractor,
                 'application/x-msdos-program': ZipExtractor,
                 'application/x-debian-package': DebExtractor,
                 'application/x-redhat-package-manager': RPMExtractor,
                 'application/x-rpm': RPMExtractor,
                 'application/x-cpio': CpioExtractor}

handler_map = {EMPTY: EmptyHandler,
               MATCHING_DIRECTORY: MatchHandler}

class ExtractorApplication(object):
    def __init__(self, arguments):
        self.parse_options(arguments)
        self.successes = []
        self.failures = []

    def parse_options(self, arguments):
        parser = optparse.OptionParser(
            usage="%prog [options] archive [archive2 ...]",
            description="Intelligent archive extractor",
            version=VERSION_BANNER
            )
        parser.add_option('-r', '--recursive', dest='recursive',
                          action='store_true', default=False,
                          help='extract archives contained in the ones listed')
        self.options, filenames = parser.parse_args(arguments)
        if not filenames:
            parser.error("you did not list any archives")
        self.archives = {os.path.realpath(os.curdir): filenames}

    def show_error(self, message):
        print >>sys.stderr, "%s: %s" % (self.current_filename, message)

    def get_extractor(self):
        mimetype, encoding = mimetypes.guess_type(self.current_filename)
        try:
            extractor = extractor_map[mimetype]
        except KeyError:
            return "not a known archive type"
        try:
            self.current_extractor = extractor(self.current_filename, mimetype,
                                               encoding)
            content = self.current_extractor.check_contents()
            handler = handler_map.get(content, BombHandler)
            self.current_handler = handler(self.current_extractor, content)
        except ExtractorError, error:
            return str(error)

    def recurse(self):
        if not self.options.recursive:
            return
        archive_path = os.path.split(self.current_filename)[0]
        for filename in self.current_extractor.included_archives:
            tail_path, basename = os.path.split(filename)
            directory = os.path.join(self.current_directory, archive_path,
                                     self.current_handler.directory, tail_path)
            self.archives.setdefault(directory, []).append(basename)

    def report(self, function, *args):
        error = function(*args)
        if error:
            self.show_error(error)
            return False
        return True

    def run(self):
        while self.archives:
            self.current_directory, filenames = self.archives.popitem()
            for filename in filenames:
                os.chdir(self.current_directory)
                self.current_filename = filename
                self.cleanup_actions = []
                success = self.report(self.get_extractor)
                if success:
                    for name in 'extract', 'cleanup':
                        success = (self.report(getattr(self.current_handler,
                                                       name)) and success)
                    self.recurse()
                if success:
                    self.successes.append(self.current_filename)
                else:
                    self.failures.append(self.current_filename)
        if self.failures:
            return 1
        return 0


if __name__ == '__main__':
    app = ExtractorApplication(sys.argv[1:])
    sys.exit(app.run())

mercurial