with-tempdir

#!/usr/bin/python
#Copyright (c) 2015, Richard Maw <richard.maw@gmail.com>
#
#Permission to use, copy, modify, and/or distribute this software for any
#purpose with or without fee is hereby granted, provided that the above
#copyright notice and this permission notice appear in all copies.
#
#THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
#WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
#MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
#ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
#WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
#ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
#OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.


'''Run a subprocess with a tempdir

Requests a tempdir from a 'name.maw.richard.tempd0' service, by talking to
a D-Bus service specified by --bus-name and --bus-object-path, and starts
a subprocess with the directory file descriptor still open on a file
descriptor referred to by the environment variable specified by --fd-env-var,
or replaces arguments equal to --fd-template.

'''


__version__ = (0, 0)


import argparse
import os
import subprocess
import sys

import dbus

parser = argparse.ArgumentParser(description=__doc__)
parser.add_argument('--version', action='version',
                    version='%(prog)s ' + '.'.join(map(str, __version__)))
parser.add_argument('--bus-name', default='name.maw.richard.tempd0',
                    help='Bus peer address to request tempdir from')
parser.add_argument('--bus-object-path', default='/name/maw/richard/tempd',
                    help='Object path of service in Bus peer')
parser.add_argument('--dir-prefix', default=None, type=str,
                    help='Prefix to name of tempdir to create')
parser.add_argument('--dir-suffix', default=None, type=str,
                    help='Suffix to name of tempdir to create')
parser.add_argument('--fd-env-var', default='TEMPDIR_FD',
                    help='Environment variable to store tempdir fd number in')
parser.add_argument('--fd-template', default=None, type=str,
                    help='Replace args equal to this with tempdir fd number')
parser.add_argument('argv', nargs='+',
                    help='Command to run with tempdir')

options = parser.parse_args()

bus = dbus.SessionBus()

temp_manager = bus.get_object(options.bus_name,
                              options.bus_object_path)
tempd = dbus.Interface(temp_manager,
                       dbus_interface='name.maw.richard.tempd0')

temp_dir, fifo_write = tempd.make_tempdir(options.dir_suffix or "",
                                          options.dir_prefix or "")
temp_dir_fd, fifo_write_fd = temp_dir.take(), fifo_write.take()

env = dict(os.environ)

if options.fd_env_var:
    env[options.fd_env_var] = str(temp_dir_fd)

if options.fd_template is None:
    argv = options.argv
else:
    argv = [str(temp_dir_fd) if arg == options.fd_template else arg
            for arg in options.argv]

sys.exit(subprocess.call(argv, env=env,
                         preexec_fn=lambda: os.close(fifo_write_fd)))