unpack.py

   1 # This is a copy of the new, unreleased, version in 0launch. Once the new
   2 # version is out, we can drop this copy.
   3
   4 import os
   5 import shutil
   6 import traceback
   7 from tempfile import mkdtemp, mkstemp
   8 import sha
   9 import re
  10 from logging import debug, info, warn
  11 from zeroinstall import SafeException
  12
  13 _recent_gnu_tar = None
  14 def recent_gnu_tar():
  15         global _recent_gnu_tar
  16         if _recent_gnu_tar is None:
  17                 _recent_gnu_tar = False
  18                 version = os.popen('tar --version 2>&1').next()
  19                 if '(GNU tar)' in version:
  20                         try:
  21                                 version = version.split(')', 1)[1].strip()
  22                                 assert version
  23                                 version = map(int, version.split('.'))
  24                                 _recent_gnu_tar = version > [1, 13, 92]
  25                         except:
  26                                 warn("Failed to extract GNU tar version number")
  27                 debug("Recent GNU tar = %s", _recent_gnu_tar)
  28         return _recent_gnu_tar
  29
  30 def unpack_archive(url, data, destdir, extract = None):
  31         """Unpack stream 'data' into directory 'destdir'. If extract is given, extract just
  32         that sub-directory from the archive. Works out the format from the name."""
  33         url = url.lower()
  34         if url.endswith('.tar.bz2'):
  35                 extract_tar(data, destdir, extract, '--bzip2')
  36         elif url.endswith('.rpm'):
  37                 extract_rpm(data, destdir, extract)
  38         elif url.endswith('.tar.gz') or url.endswith('.tgz'):
  39                 extract_tar(data, destdir, extract, '-z')
  40         else:
  41                 raise SafeException('Unknown extension on "%s"; I only know .tgz, .tar.bz2 and .rpm' % url)
  42
  43 def extract_rpm(stream, destdir, extract = None):
  44         if extract:
  45                 raise SafeException('Sorry, but the "extract" attribute is not yet supported for RPMs')
  46         fd, cpiopath = mkstemp('-rpm-tmp')
  47         try:
  48                 child = os.fork()
  49                 if child == 0:
  50                         try:
  51                                 try:
  52                                         os.dup2(stream.fileno(), 0)
  53                                         os.dup2(fd, 1)
  54                                         os.execlp('rpm2cpio', 'rpm2cpio', '-')
  55                                 except:
  56                                         traceback.print_exc()
  57                         finally:
  58                                 os._exit(1)
  59                 id, status = os.waitpid(child, 0)
  60                 assert id == child
  61                 if status != 0:
  62                         raise SafeException("rpm2cpio failed; can't unpack RPM archive; exit code %d" % status)
  63                 os.close(fd)
  64                 fd = None
  65                 args = ['cpio', '-mid', '--quiet']
  66                 _extract(file(cpiopath), destdir, args)
  67                 # Set the mtime of every directory under 'tmp' to 0, since cpio doesn't
  68                 # preserve directory mtimes.
  69                 os.path.walk(destdir, lambda arg, dirname, names: os.utime(dirname, (0, 0)), None)
  70         finally:
  71                 if fd is not None:
  72                         os.close(fd)
  73                 os.unlink(cpiopath)
  74
  75 def extract_tar(stream, destdir, extract, decompress):
  76         if extract:
  77                 # Limit the characters we accept, to avoid sending dodgy
  78                 # strings to tar
  79                 if not re.match('^[a-zA-Z0-9][- _a-zA-Z0-9.]*$', extract):
  80                         raise SafeException('Illegal character in extract attribute')
  81
  82         if recent_gnu_tar():
  83                 args = ['tar', decompress, '-x', '--no-same-owner', '--no-same-permissions']
  84         else:
  85                 args = ['tar', decompress, '-xf', '-']
  86
  87         if extract:
  88                 args.append(extract)
  89
  90         _extract(stream, destdir, args)
  91
  92 def _extract(stream, destdir, command):
  93         """Run execvp('command') inside destdir in a child process, with a
  94         rewound stream as stdin."""
  95         child = os.fork()
  96         if child == 0:
  97                 try:
  98                         try:
  99                                 os.chdir(destdir)
 100                                 stream.seek(0)
 101                                 os.dup2(stream.fileno(), 0)
 102                                 os.execvp(command[0], command)
 103                         except:
 104                                 traceback.print_exc()
 105                 finally:
 106                         os._exit(1)
 107         id, status = os.waitpid(child, 0)
 108         assert id == child
 109         if status != 0:
 110                 raise SafeException('Failed to extract archive; exit code %d' % status)