path: root/src/jarabe/util/emulator.py

# Copyright (C) 2006-2008, Red Hat, Inc.
#
# 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 St, Fifth Floor, Boston, MA  02110-1301  USA

import errno
import os
import signal
import subprocess
import sys
import time
from optparse import OptionParser
from gettext import gettext as _

import gtk

from sugar import env

DEFAULT_DIMENSIONS = (800, 600)
ERROR_NO_DISPLAY = 30
ERROR_NO_SERVER = 31
_DEV_NULL = open(os.devnull, 'w')

server = None


def _run_pipe(command, stdin=None):
    """Run a program with optional input and return output.

    Will raise CalledProcessError if program exits with non-zero return
    code.
    """
    pipe = subprocess.Popen(command, close_fds=True, stdin=subprocess.PIPE,
        stdout=subprocess.PIPE)
    stdout, stderr_ = pipe.communicate(stdin)
    if pipe.returncode:
        raise subprocess.CalledProcessError(pipe.returncode, command)

    return stdout


def _get_distro():
    """Run lsb_release to get distribution name.
    Return None if distribution name cannot be determined.
    """
    try:
        distro = ''.join(_run_pipe(['lsb_release', '-is'])).strip()
    except subprocess.CalledProcessError:
        return None

    return distro or None


def _run_xauth(display):
    """Set up Xauthority file for new display.

    Returns name of Xauthority file."""
    # pylint: disable-msg=E1103,W0612
    xauth_file = os.environ.get('XAUTHORITY',
        os.path.expanduser('~/.Xauthority'))
    host = _run_pipe(['uname', '-n']).strip()
    cookie = _run_pipe(['mcookie']).strip()
    xauth_pipe = subprocess.Popen(['xauth', '-f', xauth_file],
        stdin=subprocess.PIPE, close_fds=True)
    xauth_pipe.communicate('add %(host)s:%(display)s . %(cookie)s\n'
        'add %(host)s/unix:%(display)s . %(cookie)s\n' % locals())
    return xauth_file


def _run_server(display, dpi, dimensions, fullscreen):
    """Start the X server."""
    screen_size = (gtk.gdk.screen_width(), gtk.gdk.screen_height())

    if (not dimensions) and (fullscreen is None) and \
       (screen_size <= DEFAULT_DIMENSIONS):
        dimensions = '%dx%d' % screen_size
    elif fullscreen:
        dimensions = '%dx%d' % screen_size
    elif not dimensions:
        dimensions = '%dx%d' % DEFAULT_DIMENSIONS

    if not dpi:
        dpi = gtk.settings_get_default().get_property('gtk-xft-dpi') / 1024

    xauth_file = _run_xauth(display)
    command = ['Xvnc', '-DisconnectClients', '-NeverShared', '-localhost',
        '-SecurityTypes', 'None',
        '-auth', xauth_file,
        '-desktop', _('Sugar in a window')]
    if dimensions:
        command.append('-geometry')
        command.append(dimensions)
    if dpi:
        command.append('-dpi')
        command.append('%d' % dpi)

    if _get_distro() == 'Ubuntu':
        # workaround for Ubuntu bug #110263
        command += ['-extension', 'XFIXES']

    command.append(':%d' % (display, ))
    pipe = subprocess.Popen(command, close_fds=True)
    try:
        pipe = subprocess.Popen(cmd)

    except OSError, exc:
        sys.stderr.write('Error executing server: %s\n' % (exc, ))
        sys.exit(ERROR_NO_SERVER)

    return pipe


def _kill_pipe(pipe):
    """Terminate and wait for child process (if any)."""
    try:
        os.kill(pipe.pid, signal.SIGTERM)
    except OSError, exception:
        if exception.errno != errno.ESRCH:
            raise

    try:
        pipe.wait()
    except OSError, exception:
        if exception.errno != errno.ECHILD:
            raise


def _wait_pipe(pipe):
    """Wait for pipe to finish.

    Retries on EINTR to work around <http://bugs.python.org/issue1068268>.
    """
    while pipe.returncode is None:
        try:
            pipe.wait()
        except OSError, exception:
            if exception.errno != errno.EINTR:
                raise


def _start_server(dpi, dimensions, fullscreen):
    """Try running the X server on a free display."""
    for display in range(30, 40):
        if not _check_server(display):
            pipe = _run_server(display, dpi, dimensions, fullscreen)

            for i_ in range(10):
                if _check_server(display):
                    return display, pipe

                time.sleep(0.1)

            _kill_pipe(pipe)

    return None, None


def _start_viewer(display, fullscreen):
    """Start the VNC viewer."""
    command = ['vncviewer']
    if fullscreen:
        command.append('-fullscreen')

    command.append(':%d' % (display, ))
    pipe = subprocess.Popen(command, close_fds=True)
    return pipe


def _check_server(display):
    """Check the X server on the given display is reachable."""
    result = subprocess.call(['xdpyinfo', '-display', ':%d' % (display, )],
                             stdout=_DEV_NULL, stderr=_DEV_NULL)
    return result == 0


def _start_window_manager():
    """Start the window manager inside the new X server."""
    command = ['metacity', '--no-force-fullscreen']
    pipe_ = subprocess.Popen(command)



def _setup_env(display, scaling, emulator_pid):
    """Set up environment variables for running Sugar inside the new X server.
    """
    os.environ['SUGAR_EMULATOR'] = 'yes'
    os.environ['GABBLE_LOGFILE'] = os.path.join(
            env.get_profile_path(), 'logs', 'telepathy-gabble.log')
    os.environ['SALUT_LOGFILE'] = os.path.join(
            env.get_profile_path(), 'logs', 'telepathy-salut.log')
    os.environ['MC_LOGFILE'] = os.path.join(
            env.get_profile_path(), 'logs', 'mission-control.log')
    os.environ['STREAM_ENGINE_LOGFILE'] = os.path.join(
            env.get_profile_path(), 'logs', 'telepathy-stream-engine.log')
    os.environ['DISPLAY'] = ':%d' % (display, )
    if scaling:
        os.environ['SUGAR_SCALING'] = scaling
    os.environ['SUGAR_EMULATOR_PID'] = emulator_pid
    os.environ['MC_ACCOUNT_DIR'] = os.path.join(
            env.get_profile_path(), 'accounts')

    if scaling:
        os.environ['SUGAR_SCALING'] = scaling

def _parse_args():
    """Parse command line arguments."""
    parser = OptionParser()
    parser.add_option('-d', '--dpi', dest='dpi', type='int',
                      help='Emulator dpi')
    parser.add_option('-s', '--scaling', dest='scaling',
                      help='Sugar scaling in %')
    parser.add_option('-i', '--dimensions', dest='dimensions',
                      help='Emulator dimensions (ex. 1200x900)')
    parser.add_option('-f', '--fullscreen', dest='fullscreen',
                      action='store_true', default=None,
                      help='Run emulator in fullscreen mode')
    parser.add_option('-F', '--no-fullscreen', dest='fullscreen',
                      action='store_false',
                      help='Do not run emulator in fullscreen mode')
    return parser.parse_args()


def _sigchld_handler(number_, frame_):
    """Kill server when any (direct) child exits.

    So closing the viewer will close the server as well."""
    if server.returncode is not None:
        return

    signal.signal(signal.SIGCHLD, signal.SIG_DFL)

    print 'sugar-emulator: Child exited, shutting down server'
    _kill_pipe(server)
    return


def main():
    """Script-level operations"""
    global server

    if not os.environ.get('DISPLAY'):
        sys.stderr.write('DISPLAY not set, cannot connect to host X server.\n')
        return ERROR_NO_DISPLAY

    options, args = _parse_args()
    display, server = _start_server(options.dpi, options.dimensions,
        options.fullscreen)

    if server is None:
        sys.stderr.write('Failed to start server. Please check output above'
            ' for any error message.\n')
        return ERROR_NO_SERVER

    viewer = _start_viewer(display, options.fullscreen)
    _setup_env(display, options.scaling, str(server.pid))

    command = ['dbus-launch', '--exit-with-session']

    if not args:
        command.append('sugar')
    else:
        _start_window_manager()
        command += args

    signal.signal(signal.SIGCHLD, _sigchld_handler)
    session = subprocess.Popen(command, close_fds=True)
    _wait_pipe(session)

    _kill_pipe(viewer)
    _kill_pipe(server)