system-syslog.py

#!/usr/bin/env python3
#
# Copyright (C) 2018-2020 VyOS maintainers and contributors
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 or later as
# published by the Free Software Foundation.
#
# 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, see <http://www.gnu.org/licenses/>.

import os
import re

from sys import exit

from vyos.config import Config
from vyos import ConfigError
from vyos.util import run
from vyos.template import render

from vyos import airbag
airbag.enable()

def get_config(config=None):
    if config:
        c = config
    else:
        c = Config()
    if not c.exists('system syslog'):
        return None
    c.set_level('system syslog')

    config_data = {
        'files': {},
      'console': {},
      'hosts': {},
      'user': {}
    }

    #
    # /etc/rsyslog.d/vyos-rsyslog.conf
    # 'set system syslog global'
    #
    config_data['files'].update(
        {
            'global': {
                'log-file': '/var/log/messages',
                'max-size': 262144,
                'action-on-max-size': '/usr/sbin/logrotate /etc/logrotate.d/vyos-rsyslog',
                'selectors': '*.notice;local7.debug',
                'max-files': '5',
                'preserver_fqdn': False
            }
        }
    )

    if c.exists('global marker'):
        config_data['files']['global']['marker'] = True
        if c.exists('global marker interval'):
            config_data['files']['global'][
                'marker-interval'] = c.return_value('global marker interval')
    if c.exists('global facility'):
        config_data['files']['global'][
            'selectors'] = generate_selectors(c, 'global facility')
    if c.exists('global archive size'):
        config_data['files']['global']['max-size'] = int(
            c.return_value('global archive size')) * 1024
    if c.exists('global archive file'):
        config_data['files']['global'][
            'max-files'] = c.return_value('global archive file')
    if c.exists('global preserve-fqdn'):
        config_data['files']['global']['preserver_fqdn'] = True

    #
    # set system syslog file
    #

    if c.exists('file'):
        filenames = c.list_nodes('file')
        for filename in filenames:
            config_data['files'].update(
                {
                    filename: {
                        'log-file': '/var/log/user/' + filename,
                        'max-files': '5',
                        'action-on-max-size': '/usr/sbin/logrotate /etc/logrotate.d/' + filename,
                        'selectors': '*.err',
                        'max-size': 262144
                    }
                }
            )

            if c.exists('file ' + filename + ' facility'):
                config_data['files'][filename]['selectors'] = generate_selectors(
                    c, 'file ' + filename + ' facility')
            if c.exists('file ' + filename + ' archive size'):
                config_data['files'][filename]['max-size'] = int(
                    c.return_value('file ' + filename + ' archive size')) * 1024
            if c.exists('file ' + filename + ' archive files'):
                config_data['files'][filename]['max-files'] = c.return_value(
                    'file ' + filename + ' archive files')

    # set system syslog console
    if c.exists('console'):
        config_data['console'] = {
            '/dev/console': {
                'selectors': '*.err'
            }
        }

    for f in c.list_nodes('console facility'):
        if c.exists('console facility ' + f + ' level'):
            config_data['console'] = {
                '/dev/console': {
                    'selectors': generate_selectors(c, 'console facility')
                }
            }

    # set system syslog host
    if c.exists('host'):
        rhosts = c.list_nodes('host')
        proto = 'udp'
        for rhost in rhosts:
            for fac in c.list_nodes('host ' + rhost + ' facility'):
                if c.exists('host ' + rhost + ' facility ' + fac + ' protocol'):
                    proto = c.return_value(
                        'host ' + rhost + ' facility ' + fac + ' protocol')
                else:
                    proto = 'udp'

            config_data['hosts'].update(
                {
                    rhost: {
                        'selectors': generate_selectors(c, 'host ' + rhost + ' facility'),
                        'proto': proto
                    }
                }
            )
            if c.exists('host ' + rhost + ' port'):
                config_data['hosts'][rhost][
                    'port'] = c.return_value(['host', rhost, 'port'])

            # set system syslog host x.x.x.x format octet-counted
            if c.exists('host ' + rhost + ' format octet-counted'):
                config_data['hosts'][rhost]['oct_count'] = True
            else:
                config_data['hosts'][rhost]['oct_count'] = False

    # set system syslog user
    if c.exists('user'):
        usrs = c.list_nodes('user')
        for usr in usrs:
            config_data['user'].update(
                {
                    usr: {
                        'selectors': generate_selectors(c, 'user ' + usr + ' facility')
                    }
                }
            )

    return config_data


def generate_selectors(c, config_node):
# protocols and security are being mapped here
# for backward compatibility with old configs
# security and protocol mappings can be removed later
    nodes = c.list_nodes(config_node)
    selectors = ""
    for node in nodes:
        lvl = c.return_value(config_node + ' ' + node + ' level')
        if lvl == None:
            lvl = "err"
        if lvl == 'all':
            lvl = '*'
        if node == 'all' and node != nodes[-1]:
            selectors += "*." + lvl + ";"
        elif node == 'all':
            selectors += "*." + lvl
        elif node != nodes[-1]:
            if node == 'protocols':
                node = 'local7'
            if node == 'security':
                node = 'auth'
            selectors += node + "." + lvl + ";"
        else:
            if node == 'protocols':
                node = 'local7'
            if node == 'security':
                node = 'auth'
            selectors += node + "." + lvl
    return selectors


def generate(c):
    if c == None:
        return None

    conf = '/etc/rsyslog.d/vyos-rsyslog.conf'
    render(conf, 'syslog/rsyslog.conf.tmpl', c, trim_blocks=True)

    # eventually write for each file its own logrotate file, since size is
    # defined it shouldn't matter
    conf = '/etc/logrotate.d/vyos-rsyslog'
    render(conf, 'syslog/logrotate.tmpl', c, trim_blocks=True)


def verify(c):
    if c == None:
        return None

    # may be obsolete
    # /etc/rsyslog.conf is generated somewhere and copied over the original (exists in /opt/vyatta/etc/rsyslog.conf)
    # it interferes with the global logging, to make sure we are using a single base, template is enforced here
    #
    if not os.path.islink('/etc/rsyslog.conf'):
        os.remove('/etc/rsyslog.conf')
        os.symlink(
            '/usr/share/vyos/templates/rsyslog/rsyslog.conf', '/etc/rsyslog.conf')

    # /var/log/vyos-rsyslog were the old files, we may want to clean those up, but currently there
    # is a chance that someone still needs it, so I don't automatically remove
    # them
    #

    if c == None:
        return None

    fac = [
        '*', 'auth', 'authpriv', 'cron', 'daemon', 'kern', 'lpr', 'mail', 'mark', 'news', 'protocols', 'security',
          'syslog', 'user', 'uucp', 'local0', 'local1', 'local2', 'local3', 'local4', 'local5', 'local6', 'local7']
    lvl = ['emerg', 'alert', 'crit', 'err',
           'warning', 'notice', 'info', 'debug', '*']

    for conf in c:
        if c[conf]:
            for item in c[conf]:
                for s in c[conf][item]['selectors'].split(";"):
                    f = re.sub("\..*$", "", s)
                    if f not in fac:
                        raise ConfigError(
                            'Invalid facility ' + s + ' set in ' + conf + ' ' + item)
                    l = re.sub("^.+\.", "", s)
                    if l not in lvl:
                        raise ConfigError(
                            'Invalid logging level ' + s + ' set in ' + conf + ' ' + item)


def apply(c):
    if not c:
        return run('systemctl stop syslog.service')
    return run('systemctl restart syslog.service')

if __name__ == '__main__':
    try:
        c = get_config()
        verify(c)
        generate(c)
        apply(c)
    except ConfigError as e:
        print(e)
        exit(1)