#!/usr/bin/env python

import sys
import pwd

from os import getuid, getgid, environ, chmod, chown
from os.path import join, isdir, dirname, exists
from optparse import OptionParser
from shutil import copyfile

from rainbow.util import make_reporter, trace, make_dirs

sys.excepthook = trace

def main():
    parser = OptionParser(version='0.1')
    parser.add_option('-v', '--verbose', default=0, action='count',
                      help='Verbosity. Repeat for more verbose output.')
    parser.add_option('-q', '--quiet', default=False, action='store_true',
                      help='Quiet. Disable all output.')
    parser.add_option('-u', '--user', default=None,
                      help="Isolated user.")
    parser.add_option('-e', '--envdir', default=None,
                      help="Envdir to be used for launching.")
    opts, args = parser.parse_args()
    if not opts.user or not opts.envdir:
        parser.print_help()
        exit(1)

    report = make_reporter(opts.verbose, opts.quiet, sys.stdout)

    def check_user(report, opts):
        report(1, 'X-ifying isolated uid %s.', opts.user)
        return opts.user

    def check_envdir(report, envdir):
        report(1, 'X-ifying envdir %s.', envdir)
        assert isdir(envdir)
        def write_envvar(k, v):
            report(1, '-E %s=%s', k, v)
            open(join(envdir, k), 'w').write(v)
        return write_envvar

    user = check_user(report, opts)
    write_envvar = check_envdir(report, opts.envdir)

    o = pwd.getpwuid(getuid())
    i = pwd.getpwnam(user)
    h_o = o.pw_dir
    h_i = i.pw_dir

    # XXX: Is it _always_ right to set these defaults? <MS>
    environ.setdefault('XAUTHORITY', join(h_o, '.Xauthority'))
    environ.setdefault('ICEAUTHORITY', join(h_o, '.ICEauthority'))

    for cookie in ['XAUTHORITY', 'ICEAUTHORITY']:
        if exists(environ[cookie]):
            cookie_path = join(h_i, cookie)
            make_dirs(dirname(cookie_path), getuid(), getgid(), 0777)
            copyfile(environ[cookie], cookie_path)
            chmod(cookie_path, 0666)
            chown(cookie_path, o.pw_uid, i.pw_gid)
            write_envvar(cookie, cookie_path)
        else:
            report(1, "Cookie %s -> %s which doesn't exist.", cookie, environ[cookie])

    write_envvar('USER', i.pw_name)
    write_envvar('HOME', h_i)
    #write_envvar('TMPDIR', join(h_i, 'tmp'))
    if 'DISPLAY' in environ:
        write_envvar('DISPLAY', environ['DISPLAY'])

if __name__ == '__main__':
    main()

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