##############################################################################
#
# Copyright (c) 2002 Zope Corporation and Contributors.
# All Rights Reserved.
#
# This software is subject to the provisions of the Zope Public License,
# Version 2.1 (ZPL).  A copy of the ZPL should accompany this distribution.
# THIS SOFTWARE IS PROVIDED "AS IS" AND ANY AND ALL EXPRESS OR IMPLIED
# WARRANTIES ARE DISCLAIMED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
# WARRANTIES OF TITLE, MERCHANTABILITY, AGAINST INFRINGEMENT, AND FITNESS
# FOR A PARTICULAR PURPOSE.
#
##############################################################################

""" Startup package.  Responsible for startup configuration of Zope """

import logging
import os
import sys
import socket
from re import compile
from socket import gethostbyaddr

import ZConfig

from ZConfig.components.logger import loghandler


logger = logging.getLogger("Zope")
started = False

def get_starter():
    check_python_version()
    if sys.platform[:3].lower() == "win":
        return WindowsZopeStarter()
    else:
        return UnixZopeStarter()

def start_zope(cfg, debug_handler):
    """The function called by run.py which starts a Zope appserver."""
    global started
    if started:
        # Don't allow any code to call start_zope() twice.
        return

    starter = get_starter()
    starter.setConfiguration(cfg)
    starter.prepare()

    started = True
    try:
        starter.run()
    finally:
        started = False


class ZopeStarter:
    """This is a class which starts a Zope server.

    Making it a class makes it easier to test.
    """
    def __init__(self):
        self.event_logger = logging.getLogger()
        # We log events to the root logger, which is backed by a
        # "StartupHandler" log handler.  The "StartupHandler" buffers
        # log messages.  When the "real" loggers are set up, we flush
        # accumulated messages in StartupHandler's buffers to the real
        # logger.
        formatter = logging.Formatter(
            "%(asctime)s %(levelname)s %(name)s %(message)s",
            "%Y-%m-%d %H:%M:%S")
        self.debug_handler = loghandler.StreamHandler()
        self.debug_handler.setFormatter(formatter)
        self.debug_handler.setLevel(logging.WARN)

        self.startup_handler = loghandler.StartupHandler()

        self.event_logger.addHandler(self.debug_handler)
        self.event_logger.addHandler(self.startup_handler)

    def setConfiguration(self, cfg):
        self.cfg = cfg

    def prepare(self):
        self.setupInitialLogging()
        self.setupLocale()
        self.setupSecurityOptions()
        self.setupPublisher()
        # Start ZServer servers before we drop privileges so we can bind to
        # "low" ports:
        self.setupZServer()
        self.setupServers()
        # drop privileges after setting up servers
        self.dropPrivileges()
        self.makeLockFile()
        self.makePidFile()
        self.setupInterpreter()
        self.startZope()
        self.registerSignals()
        # emit a "ready" message in order to prevent the kinds of emails
        # to the Zope maillist in which people claim that Zope has "frozen"
        # after it has emitted ZServer messages.
        logger.info('Ready to handle requests')
        self.setupFinalLogging()

    def run(self):
        # the mainloop.
        try:
            import ZServer
            import Lifetime
            Lifetime.loop()
            sys.exit(ZServer.exit_code)
        finally:
            self.shutdown()

    def shutdown(self):
        self.unlinkLockFile()
        self.unlinkPidFile()

    # XXX does anyone actually use these three?

    def info(self, msg):
        logger.info(msg)

    def panic(self, msg):
        logger.critical(msg)

    def error(self, msg):
        logger.error(msg)

    def setupPublisher(self):
        import Globals
        import ZPublisher.HTTPRequest
        import ZPublisher.Publish
        Globals.DevelopmentMode = self.cfg.debug_mode
        ZPublisher.Publish.set_default_debug_mode(self.cfg.debug_mode)
        ZPublisher.Publish.set_default_authentication_realm(
            self.cfg.http_realm)
        if self.cfg.publisher_profile_file:
            filename = self.cfg.publisher_profile_file
            ZPublisher.Publish.install_profiling(filename)
        if self.cfg.trusted_proxies:
            # DM 2004-11-24: added host name mapping (such that examples in conf file really have a chance to work
            mapped = []
            for name in self.cfg.trusted_proxies: mapped.extend(_name2Ips(name))
            ZPublisher.HTTPRequest.trusted_proxies = tuple(mapped)

    def setupSecurityOptions(self):
        import AccessControl
        AccessControl.setImplementation(
            self.cfg.security_policy_implementation)
        AccessControl.setDefaultBehaviors(
            not self.cfg.skip_ownership_checking,
            not self.cfg.skip_authentication_checking,
            self.cfg.verbose_security)

    def setupLocale(self):
        # set a locale if one has been specified in the config
        if not self.cfg.locale:
            return

        # workaround to allow unicode encoding conversions in DTML
        import codecs
        dummy = codecs.lookup('iso-8859-1')

        locale_id = self.cfg.locale

        if locale_id is not None:
            try:
                import locale
            except:
                raise ZConfig.ConfigurationError(
                    'The locale module could not be imported.\n'
                    'To use localization options, you must ensure\n'
                    'that the locale module is compiled into your\n'
                    'Python installation.'
                    )
            try:
                locale.setlocale(locale.LC_ALL, locale_id)
            except:
                raise ZConfig.ConfigurationError(
                    'The specified locale "%s" is not supported by your'
                    'system.\nSee your operating system documentation for '
                    'more\ninformation on locale support.' % locale_id
                    )

    def setupZServer(self):
        # Increase the number of threads
        import ZServer
        ZServer.setNumberOfThreads(self.cfg.zserver_threads)
        ZServer.CONNECTION_LIMIT = self.cfg.max_listen_sockets

    def setupServers(self):
        socket_err = (
            'There was a problem starting a server of type "%s". '
            'This may mean that your user does not have permission to '
            'bind to the port which the server is trying to use or the '
            'port may already be in use by another application. '
            '(%s)'
            )
        servers = []
        for server in self.cfg.servers:
            # create the server from the server factory
            # set up in the config
            try:
                servers.append(server.create())
            except socket.error,e:
                raise ZConfig.ConfigurationError(socket_err
                                                 % (server.servertype(),e[1]))
        self.cfg.servers = servers

    def dropPrivileges(self):
        return dropPrivileges(self.cfg)

    def getLoggingLevel(self):
        if self.cfg.eventlog is None:
            level = logging.INFO
        else:
            # get the lowest handler level.  This is the effective level
            # level at which which we will spew messages to the console
            # during startup.
            level = self.cfg.eventlog.getLowestHandlerLevel()
        return level

    def setupConfiguredLoggers(self):
        # Must happen after ZopeStarter.setupInitialLogging()
        self.event_logger.removeHandler(self.startup_handler)
        if self.cfg.zserver_read_only_mode:
            # no log files written in read only mode
            return

        if self.cfg.eventlog is not None:
            self.cfg.eventlog()
        if self.cfg.access is not None:
            self.cfg.access()
        if self.cfg.trace is not None:
            self.cfg.trace()

        # flush buffered startup messages to event logger
        if self.cfg.debug_mode:
            self.event_logger.removeHandler(self.debug_handler)
            self.startup_handler.flushBufferTo(self.event_logger)
            self.event_logger.addHandler(self.debug_handler)
        else:
            self.startup_handler.flushBufferTo(self.event_logger)

    def setupInitialLogging(self):
        if self.cfg.debug_mode:
            self.debug_handler.setLevel(self.getLoggingLevel())
        else:
            self.event_logger.removeHandler(self.debug_handler)
            self.debug_handler = None

    def startZope(self):
        # Import Zope
        import Zope2
        Zope2.startup()

    def makeLockFile(self):
        if not self.cfg.zserver_read_only_mode:
            # lock_file is used for the benefit of zctl-like systems, so they
            # can tell whether Zope is already running before attempting to
            # fire it off again.
            #
            # We aren't concerned about locking the file to protect against
            # other Zope instances running from our CLIENT_HOME, we just
            # try to lock the file to signal that zctl should not try to
            # start Zope if *it* can't lock the file; we don't panic
            # if we can't lock it.
            # we need a separate lock file because on win32, locks are not
            # advisory, otherwise we would just use the pid file
            from Zope2.Startup.misc.lock_file import lock_file
            lock_filename = self.cfg.lock_filename
            try:
                if os.path.exists(lock_filename):
                    os.unlink(lock_filename)
                self.lockfile = open(lock_filename, 'w')
                lock_file(self.lockfile)
                self.lockfile.write(str(os.getpid()))
                self.lockfile.flush()
            except IOError:
                pass

    def makePidFile(self):
        if not self.cfg.zserver_read_only_mode:
            # write the pid into the pidfile if possible
            try:
                if os.path.exists(self.cfg.pid_filename):
                    os.unlink(self.cfg.pid_filename)
                f = open(self.cfg.pid_filename, 'w')
                f.write(str(os.getpid()))
                f.close()
            except IOError:
                pass

    def unlinkPidFile(self):
        if not self.cfg.zserver_read_only_mode:
            try:
                os.unlink(self.cfg.pid_filename)
            except OSError:
                pass

    def unlinkLockFile(self):
        if not self.cfg.zserver_read_only_mode:
            try:
                self.lockfile.close()
                os.unlink(self.cfg.lock_filename)
            except OSError:
                pass

    def setupInterpreter(self):
        """ make changes to the python interpreter environment """
        sys.setcheckinterval(self.cfg.python_check_interval)


class WindowsZopeStarter(ZopeStarter):

    def registerSignals(self):
        from Signals import Signals
        Signals.registerZopeSignals([self.cfg.eventlog,
                                     self.cfg.access,
                                     self.cfg.trace])

    def setupInitialLogging(self):
        ZopeStarter.setupInitialLogging(self)
        self.setupConfiguredLoggers()

    def setupFinalLogging(self):
        pass


class UnixZopeStarter(ZopeStarter):

    def registerSignals(self):
        from Signals import Signals
        Signals.registerZopeSignals([self.cfg.eventlog,
                                     self.cfg.access,
                                     self.cfg.trace])

    def setupInitialLogging(self):
        ZopeStarter.setupInitialLogging(self)
        level = self.getLoggingLevel()

        self.startup_handler.setLevel(level)

        # set the initial logging level (this will be changed by the
        # zconfig settings later)
        self.event_logger.setLevel(level)

    def setupFinalLogging(self):
        self.setupConfiguredLoggers()


def check_python_version():
    # check for Python version
    python_version = sys.version.split()[0]
    optimum_version = '2.3.4'
    if python_version < '2.3.4':
        raise ZConfig.ConfigurationError(
            'Invalid python version: %s, the optimal version is %s or higher' %
            (python_version, optimum_version))


def dropPrivileges(cfg):
    # Drop root privileges if we have them and we're on a posix platform.
    # This needs to be a function so it may be used outside of Zope
    # appserver startup (e.g. from zopectl debug)
    if os.name != 'posix':
        return

    if os.getuid() != 0:
        return

    import pwd

    effective_user  = cfg.effective_user
    if effective_user is None:
        msg = ('A user was not specified to setuid to; fix this to '
               'start as root (change the effective-user directive '
               'in zope.conf)')
        logger.critical(msg)
        raise ZConfig.ConfigurationError(msg)

    try:
        uid = int(effective_user)
    except ValueError:
        try:
            pwrec = pwd.getpwnam(effective_user)
        except KeyError:
            msg = "Can't find username %r" % effective_user
            logger.error(msg)
            raise ZConfig.ConfigurationError(msg)
        uid = pwrec[2]
    else:
        try:
            pwrec = pwd.getpwuid(uid)
        except KeyError:
            msg = "Can't find uid %r" % uid
            logger.error(msg)
            raise ZConfig.ConfigurationError(msg)
    gid = pwrec[3]

    if uid == 0:
        msg = 'Cannot start Zope with the effective user as the root user'
        logger.error(msg)
        raise ZConfig.ConfigurationError(msg)

    try:
        import initgroups
        initgroups.initgroups(effective_user, gid)
        os.setgid(gid)
    except OSError:
        logger.exception('Could not set group id of effective user')

    os.setuid(uid)
    logger.info('Set effective user to "%s"' % effective_user)
    return 1 # for unit testing purposes 


# DM 2004-11-24: added
def _name2Ips(host, isIp_=compile(r'(\d+\.){3}').match):
    '''map a name *host* to the sequence of its ip addresses;
    use *host* itself (as sequence) if it already is an ip address.
    Thus, if only a specific interface on a host is trusted,
    identify it by its ip (and not the host name).
    '''
    if isIp_(host): return [host]
    return gethostbyaddr(host)[2]