Page MenuHomeSoftware Heritage
Files F8392262

tarball.py
No OneTemporary
Actions

tarball.py
View Options

# Copyright (C) 2015-2017 The Software Heritage developers
# See the AUTHORS file at the top-level directory of this distribution
# License: GNU General Public License version 3, or any later version
# See top-level LICENSE file for more information
import os
import stat
import tarfile
import zipfile
from os.path import abspath, realpath, join, dirname
from . import utils
def _canonical_abspath(path):
"""Resolve all paths to an absolute and real one.
Args:
path: to resolve
Returns:
canonical absolute path to path
"""
return realpath(abspath(path))
def _badpath(path, basepath):
"""Determine if a path is outside basepath.
Args:
path: a relative or absolute path of a file or directory
basepath: the basepath path must be in
Returns:
True if path is outside basepath, false otherwise.
"""
return not _canonical_abspath(join(basepath, path)).startswith(basepath)
def _badlink(info, basepath):
"""Determine if the tarinfo member is outside basepath.
Args:
info: TarInfo member representing a symlink or hardlink of tar archive
basepath: the basepath the info member must be in
Returns:
True if info is outside basepath, false otherwise.
"""
tippath = _canonical_abspath(join(basepath, dirname(info.name)))
return _badpath(info.linkname, basepath=tippath)
def is_tarball(filepath):
"""Given a filepath, determine if it represents an archive.
Args:
filepath: file to test for tarball property
Returns:
Bool, True if it's a tarball, False otherwise
"""
return tarfile.is_tarfile(filepath) or zipfile.is_zipfile(filepath)
def _uncompress_zip(tarpath, dirpath):
"""Uncompress zip archive safely.
As per zipfile is concerned
(cf. note on https://docs.python.org/3.5/library/zipfile.html#zipfile.ZipFile.extract) # noqa
Args:
tarpath: path to the archive
dirpath: directory to uncompress the archive to
"""
with zipfile.ZipFile(tarpath) as z:
z.extractall(path=dirpath)
def _uncompress_tar(tarpath, dirpath):
"""Uncompress tarpath if the tarpath is safe.
Safe means, no file will be uncompressed outside of dirpath.
Args:
tarpath: path to the archive
dirpath: directory to uncompress the archive to
Raises:
ValueError when a member would be extracted outside dirpath.
"""
def safemembers(tarpath, members, basepath):
"""Given a list of archive members, yield the members (directory,
file, hard-link) that stays in bounds with basepath. Note
that symbolic link are authorized to point outside the
basepath though.
Args:
tarpath: Name of the tarball
members: Archive members for such tarball
basepath: the basepath sandbox
Yields:
Safe TarInfo member
Raises:
ValueError when a member would be extracted outside basepath
"""
errormsg = 'Archive {} blocked. Illegal path to %s %s'.format(tarpath)
for finfo in members:
if finfo.isdir() and _badpath(finfo.name, basepath):
raise ValueError(errormsg % ('directory', finfo.name))
elif finfo.isfile() and _badpath(finfo.name, basepath):
raise ValueError(errormsg % ('file', finfo.name))
elif finfo.islnk() and _badlink(finfo, basepath):
raise ValueError(errormsg % ('hard-link', finfo.linkname))
# Authorize symlinks to point outside basepath
# elif finfo.issym() and _badlink(finfo, basepath):
# raise ValueError(errormsg % ('symlink', finfo.linkname))
else:
yield finfo
with tarfile.open(tarpath) as t:
members = t.getmembers()
t.extractall(path=dirpath,
members=safemembers(tarpath, members, dirpath))
def uncompress(tarpath, dest):
"""Uncompress tarpath to dest folder if tarball is supported and safe.
Safe means, no file will be uncompressed outside of dirpath.
Note that this fixes permissions after successfully
uncompressing the archive.
Args:
tarpath: path to tarball to uncompress
dest: the destination folder where to uncompress the tarball
Returns:
The nature of the tarball, zip or tar.
Raises:
ValueError when:
- an archive member would be extracted outside basepath
- the archive is not supported
"""
if tarfile.is_tarfile(tarpath):
_uncompress_tar(tarpath, dest)
nature = 'tar'
elif zipfile.is_zipfile(tarpath):
_uncompress_zip(tarpath, dest)
nature = 'zip'
else:
raise ValueError('File %s is not a supported archive.' % tarpath)
# Fix permissions
for dirpath, _, fnames in os.walk(dest):
os.chmod(dirpath, 0o755)
for fname in fnames:
fpath = os.path.join(dirpath, fname)
if not os.path.islink(fpath):
fpath_exec = os.stat(fpath).st_mode & stat.S_IXUSR
if not fpath_exec:
os.chmod(fpath, 0o644)
return nature
def _ls(rootdir):
"""Generator of filepath, filename from rootdir.
"""
for dirpath, dirnames, fnames in os.walk(rootdir):
for fname in (dirnames+fnames):
fpath = os.path.join(dirpath, fname)
fname = utils.commonname(rootdir, fpath)
yield fpath, fname
def _compress_zip(tarpath, files):
"""Compress dirpath's content as tarpath.
"""
with zipfile.ZipFile(tarpath, 'w') as z:
for fpath, fname in files:
z.write(fpath, arcname=fname)
def _compress_tar(tarpath, files):
"""Compress dirpath's content as tarpath.
"""
with tarfile.open(tarpath, 'w:bz2') as t:
for fpath, fname in files:
t.add(fpath, arcname=fname, recursive=False)
def compress(tarpath, nature, dirpath_or_files):
"""Create a tarball tarpath with nature nature.
The content of the tarball is either dirpath's content (if representing
a directory path) or dirpath's iterable contents.
Compress the directory dirpath's content to a tarball.
The tarball being dumped at tarpath.
The nature of the tarball is determined by the nature argument.
"""
if isinstance(dirpath_or_files, str):
files = _ls(dirpath_or_files)
else: # iterable of 'filepath, filename'
files = dirpath_or_files
if nature == 'zip':
_compress_zip(tarpath, files)
else:
_compress_tar(tarpath, files)
return tarpath

File Metadata

Mime Type
text/x-python
Expires
Jun 4 2025, 6:56 PM (11 w, 3 d ago)
Storage Engine
blob
Storage Format
Raw Data
Storage Handle
3283844

Event Timeline

About · Developer information · Legal