# -*- Mode: Python; tab-width: 4 -*-

# ======================================================================
# Copyright 1997 by Sam Rushing
#
#                         All Rights Reserved
#
# Permission to use, copy, modify, and distribute this software and
# its documentation for any purpose and without fee is hereby
# granted, provided that the above copyright notice appear in all
# copies and that both that copyright notice and this permission
# notice appear in supporting documentation, and that the name of Sam
# Rushing not be used in advertising or publicity pertaining to
# distribution of the software without specific, written prior
# permission.
#
# SAM RUSHING DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
# INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN
# NO EVENT SHALL SAM RUSHING BE LIABLE FOR ANY SPECIAL, INDIRECT OR
# CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS
# OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT,
# NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
# CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
# ======================================================================

"""socket interface to unix syslog.
On Unix, there are usually two ways of getting to syslog: via a
local unix-domain socket, or via the TCP service.

Usually "/dev/log" is the unix domain socket.  This may be different
for other systems.

>>> my_client = syslog_client ('/dev/log')

Otherwise, just use the UDP version, port 514.

>>> my_client = syslog_client (('my_log_host', 514))

On win32, you will have to use the UDP version.  Note that
you can use this to log to other hosts (and indeed, multiple
hosts).

This module is not a drop-in replacement for the python
<syslog> extension module - the interface is different.

Usage:

>>> c = syslog_client()
>>> c = syslog_client ('/strange/non_standard_log_location')
>>> c = syslog_client (('other_host.com', 514))
>>> c.log ('testing', facility='local0', priority='debug')

"""

# TODO: support named-pipe syslog.
# [see ftp://sunsite.unc.edu/pub/Linux/system/Daemons/syslog-fifo.tar.z]

# from <linux/sys/syslog.h>:
# ===========================================================================
# priorities/facilities are encoded into a single 32-bit quantity, where the
# bottom 3 bits are the priority (0-7) and the top 28 bits are the facility
# (0-big number).  Both the priorities and the facilities map roughly
# one-to-one to strings in the syslogd(8) source code.  This mapping is
# included in this file.
#
# priorities (these are ordered)

LOG_EMERG                = 0                #  system is unusable
LOG_ALERT                = 1                #  action must be taken immediately
LOG_CRIT                 = 2                #  critical conditions
LOG_ERR                  = 3                #  error conditions
LOG_WARNING              = 4                #  warning conditions
LOG_NOTICE               = 5                #  normal but significant condition
LOG_INFO                 = 6                #  informational
LOG_DEBUG                = 7                #  debug-level messages

#  facility codes
LOG_KERN                 = 0                #  kernel messages
LOG_USER                 = 1                #  random user-level messages
LOG_MAIL                 = 2                #  mail system
LOG_DAEMON               = 3                #  system daemons
LOG_AUTH                 = 4                #  security/authorization messages
LOG_SYSLOG               = 5                #  messages generated internally by syslogd
LOG_LPR                  = 6                #  line printer subsystem
LOG_NEWS                 = 7                #  network news subsystem
LOG_UUCP                 = 8                #  UUCP subsystem
LOG_CRON                 = 9                #  clock daemon
LOG_AUTHPRIV             = 10               #  security/authorization messages (private)

#  other codes through 15 reserved for system use
LOG_LOCAL0               = 16               #  reserved for local use
LOG_LOCAL1               = 17               #  reserved for local use
LOG_LOCAL2               = 18               #  reserved for local use
LOG_LOCAL3               = 19               #  reserved for local use
LOG_LOCAL4               = 20               #  reserved for local use
LOG_LOCAL5               = 21               #  reserved for local use
LOG_LOCAL6               = 22               #  reserved for local use
LOG_LOCAL7               = 23               #  reserved for local use

priority_names = {
    "alert":         LOG_ALERT,
    "crit":          LOG_CRIT,
    "debug":         LOG_DEBUG,
    "emerg":         LOG_EMERG,
    "err":           LOG_ERR,
    "error":         LOG_ERR,               #  DEPRECATED
    "info":          LOG_INFO,
    "notice":        LOG_NOTICE,
    "panic":         LOG_EMERG,             #  DEPRECATED
    "warn":          LOG_WARNING,           #  DEPRECATED
    "warning":       LOG_WARNING,
    }

facility_names = {
    "auth":          LOG_AUTH,
    "authpriv":      LOG_AUTHPRIV,
    "cron":          LOG_CRON,
    "daemon":        LOG_DAEMON,
    "kern":          LOG_KERN,
    "lpr":           LOG_LPR,
    "mail":          LOG_MAIL,
    "news":          LOG_NEWS,
    "security":      LOG_AUTH,              #  DEPRECATED
    "syslog":        LOG_SYSLOG,
    "user":          LOG_USER,
    "uucp":          LOG_UUCP,
    "local0":        LOG_LOCAL0,
    "local1":        LOG_LOCAL1,
    "local2":        LOG_LOCAL2,
    "local3":        LOG_LOCAL3,
    "local4":        LOG_LOCAL4,
    "local5":        LOG_LOCAL5,
    "local6":        LOG_LOCAL6,
    "local7":        LOG_LOCAL7,
    }

import socket

class syslog_client(object):

    def __init__(self, address='/dev/log'):
        self.address = address
        if type(address) == type(''):
            try: # APUE 13.4.2 specifes /dev/log as datagram socket
                self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM)
                self.socket.connect(address)
            except: # older linux may create as stream socket
                self.socket = socket.socket(socket.AF_UNIX, socket.SOCK_STREAM)
                self.socket.connect(address)
            self.unix = 1
        else:
            self.socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
            self.unix = 0


    log_format_string = '<%d>%s\000'

    def log(self, message, facility=LOG_USER, priority=LOG_INFO):
        message = self.log_format_string % (
            self.encode_priority(facility, priority),
            message
            )
        if self.unix:
            self.socket.send(message)
        else:
            self.socket.sendto(message, self.address)

    def encode_priority(self, facility, priority):
        if type(facility) == type(''):
            facility = facility_names[facility]
        if type(priority) == type(''):
            priority = priority_names[priority]
        return (facility<<3) | priority

    def close(self):
        if self.unix:
            self.socket.close()
