FreedomBox/plinth/modules/config/config.py

#
# This file is part of Plinth.
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as
# published by the Free Software Foundation, either version 3 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 Affero General Public License for more details.
#
# You should have received a copy of the GNU Affero General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#

"""
Plinth module for configuring hostname and domainname.
"""

from django import forms
from django.contrib import messages
from django.core import validators
from django.template.response import TemplateResponse
from django.utils.translation import ugettext as _, ugettext_lazy
import logging
import socket

from plinth import actions
from plinth import cfg
from plinth.signals import pre_hostname_change, post_hostname_change
from plinth.signals import domainname_change


LOGGER = logging.getLogger(__name__)


def get_hostname():
    """Return the hostname"""
    return socket.gethostname()


def get_domainname():
    """Return the domainname"""
    fqdn = socket.getfqdn()
    return '.'.join(fqdn.split('.')[1:])


class TrimmedCharField(forms.CharField):
    """Trim the contents of a CharField"""
    def clean(self, value):
        """Clean and validate the field value"""
        if value:
            value = value.strip()

        return super(TrimmedCharField, self).clean(value)


class ConfigurationForm(forms.Form):
    """Main system configuration form"""
    # See:
    # https://tools.ietf.org/html/rfc952
    # https://tools.ietf.org/html/rfc1035#section-2.3.1
    # https://tools.ietf.org/html/rfc1123#section-2
    # https://tools.ietf.org/html/rfc2181#section-11
    hostname = TrimmedCharField(
        label=ugettext_lazy('Hostname'),
        help_text=\
        ugettext_lazy('Hostname is the local name by which other machines on '
                      'the local network reach your machine.  It must start '
                      'and end with an alphabet or a digit and have as '
                      'interior characters only alphabets, digits and '
                      'hyphens.  Total length must be 63 characters or less.'),
        validators=[
            validators.RegexValidator(
                r'^[a-zA-Z0-9]([-a-zA-Z0-9]{,61}[a-zA-Z0-9])?$',
                ugettext_lazy('Invalid hostname'))])

    domainname = TrimmedCharField(
        label=ugettext_lazy('Domain Name'),
        help_text=\
        ugettext_lazy('Domain name is the global name by which other machines '
                      'on the Internet can reach you.  It must consist of '
                      'labels separated by dots.  Each label must start and '
                      'end with an alphabet or a digit and have as interior '
                      'characters only alphabets, digits and hyphens.  Length '
                      'of each label must be 63 characters or less.  Total '
                      'length of domain name must be 253 characters or less.'),
        required=False,
        validators=[
            validators.RegexValidator(
                r'^[a-zA-Z0-9]([-a-zA-Z0-9.]*[a-zA-Z0-9])?$',
                ugettext_lazy('Invalid domain name'))])


def init():
    """Initialize the module"""
    menu = cfg.main_menu.get('system:index')
    menu.add_urlname(ugettext_lazy('Configure'), 'glyphicon-cog',
                     'config:index', 10)


def index(request):
    """Serve the configuration form"""
    status = get_status()

    form = None

    if request.method == 'POST':
        form = ConfigurationForm(request.POST, initial=status,
                                 prefix='configuration')
        # pylint: disable-msg=E1101
        if form.is_valid():
            _apply_changes(request, status, form.cleaned_data)
            status = get_status()
            form = ConfigurationForm(initial=status,
                                     prefix='configuration')
    else:
        form = ConfigurationForm(initial=status, prefix='configuration')

    return TemplateResponse(request, 'config.html',
                            {'title': _('General Configuration'),
                             'form': form})


def get_status():
    """Return the current status"""
    return {'hostname': get_hostname(),
            'domainname': get_domainname()}


def _apply_changes(request, old_status, new_status):
    """Apply the form changes"""
    if old_status['hostname'] != new_status['hostname']:
        try:
            set_hostname(new_status['hostname'])
        except Exception as exception:
            messages.error(request, _('Error setting hostname: {exception}')
                           .format(exception=exception))
        else:
            messages.success(request, _('Hostname set'))
    else:
        messages.info(request, _('Hostname is unchanged'))

    if old_status['domainname'] != new_status['domainname']:
        try:
            set_domainname(new_status['domainname'])
        except Exception as exception:
            messages.error(request, _('Error setting domain name: {exception}')
                           .format(exception=exception))
        else:
            messages.success(request, _('Domain name set'))
    else:
        messages.info(request, _('Domain name is unchanged'))


def set_hostname(hostname):
    """Sets machine hostname to hostname"""
    old_hostname = get_hostname()

    # Hostname should be ASCII. If it's unicode but passed our
    # valid_hostname check, convert to ASCII.
    hostname = str(hostname)

    pre_hostname_change.send_robust(sender='config',
                                    old_hostname=old_hostname,
                                    new_hostname=hostname)

    LOGGER.info('Changing hostname to - %s', hostname)
    actions.superuser_run('hostname-change', [hostname])

    post_hostname_change.send_robust(sender='config',
                                     old_hostname=old_hostname,
                                     new_hostname=hostname)


def set_domainname(domainname):
    """Sets machine domain name to domainname"""
    old_domainname = get_domainname()

    # Domain name should be ASCII. If it's unicode, convert to ASCII.
    domainname = str(domainname)

    LOGGER.info('Changing domain name to - %s', domainname)
    actions.superuser_run('domainname-change', [domainname])

    domainname_change.send_robust(sender='config',
                                  old_domainname=old_domainname,
                                  new_domainname=domainname)