syslog.pm

视频监控网络部分的协议ddns,的模块的实现代码,请大家大胆指正.

=back

A reference to an array can also be passed as the first parameter.
When this calling method is used, the array should contain a list of
mechanisms which are attempted in order.

The default is to try C<native>, C<tcp>, C<udp>, C<unix>, C<stream>, C<console>.
Under systems with the Win32 API, C<eventlog> will be added as the first 
mechanism to try if C<Win32::EventLog> is available.

Giving an invalid value for C<$sock_type> will C<croak>.

B<Examples>

Select the UDP socket mechanism: 

    setlogsock("udp");

Select the native, UDP socket then UNIX domain socket mechanisms: 

    setlogsock(["native", "udp", "unix"]);

=over

=item B<Note>

Now that the "native" mechanism is supported by C<Sys::Syslog> and selected 
by default, the use of the C<setlogsock()> function is discouraged because 
other mechanisms are less portable across operating systems.  Authors of 
modules and programs that use this function, especially its cargo-cult form 
C<setlogsock("unix")>, are advised to remove any occurence of it unless they 
specifically want to use a given mechanism (like TCP or UDP to connect to 
a remote host).

=back

=item B<closelog()>

Closes the log file and returns true on success.

=back


=head1 THE RULES OF SYS::SYSLOG

I<The First Rule of Sys::Syslog is:>
You do not call C<setlogsock>.

I<The Second Rule of Sys::Syslog is:>
You B<do not> call C<setlogsock>.

I<The Third Rule of Sys::Syslog is:>
The program crashes, C<die>s, calls C<closelog>, the log is over.

I<The Fourth Rule of Sys::Syslog is:>
One facility, one priority.

I<The Fifth Rule of Sys::Syslog is:>
One log at a time.

I<The Sixth Rule of Sys::Syslog is:>
No C<syslog> before C<openlog>.

I<The Seventh Rule of Sys::Syslog is:>
Logs will go on as long as they have to. 

I<The Eighth, and Final Rule of Sys::Syslog is:>
If this is your first use of Sys::Syslog, you must read the doc.


=head1 EXAMPLES

An example:

    openlog($program, 'cons,pid', 'user');
    syslog('info', '%s', 'this is another test');
    syslog('mail|warning', 'this is a better test: %d', time);
    closelog();

    syslog('debug', 'this is the last test');

Another example:

    openlog("$program $$", 'ndelay', 'user');
    syslog('notice', 'fooprogram: this is really done');

Example of use of C<%m>:

    $! = 55;
    syslog('info', 'problem was %m');   # %m == $! in syslog(3)

Log to UDP port on C<$remotehost> instead of logging locally:

    setlogsock('udp');
    $Sys::Syslog::host = $remotehost;
    openlog($program, 'ndelay', 'user');
    syslog('info', 'something happened over here');


=head1 CONSTANTS

=head2 Facilities

=over 4

=item *

C<LOG_AUDIT> - audit daemon (IRIX); falls back to C<LOG_AUTH>

=item *

C<LOG_AUTH> - security/authorization messages

=item *

C<LOG_AUTHPRIV> - security/authorization messages (private)

=item *

C<LOG_CONSOLE> - C</dev/console> output (FreeBSD); falls back to C<LOG_USER>

=item *

C<LOG_CRON> - clock daemons (B<cron> and B<at>)

=item *

C<LOG_DAEMON> - system daemons without separate facility value

=item *

C<LOG_FTP> - FTP daemon

=item *

C<LOG_KERN> - kernel messages

=item *

C<LOG_INSTALL> - installer subsystem (Mac OS X); falls back to C<LOG_USER>

=item *

C<LOG_LAUNCHD> - launchd - general bootstrap daemon (Mac OS X);
falls back to C<LOG_DAEMON>

=item *

C<LOG_LFMT> - logalert facility; falls back to C<LOG_USER>

=item *

C<LOG_LOCAL0> through C<LOG_LOCAL7> - reserved for local use

=item *

C<LOG_LPR> - line printer subsystem

=item *

C<LOG_MAIL> - mail subsystem

=item *

C<LOG_NETINFO> - NetInfo subsystem (Mac OS X); falls back to C<LOG_DAEMON>

=item *

C<LOG_NEWS> - USENET news subsystem

=item *

C<LOG_NTP> - NTP subsystem (FreeBSD, NetBSD); falls back to C<LOG_DAEMON>

=item *

C<LOG_RAS> - Remote Access Service (VPN / PPP) (Mac OS X);
falls back to C<LOG_AUTH>

=item *

C<LOG_REMOTEAUTH> - remote authentication/authorization (Mac OS X);
falls back to C<LOG_AUTH>

=item *

C<LOG_SECURITY> - security subsystems (firewalling, etc.) (FreeBSD);
falls back to C<LOG_AUTH>

=item *

C<LOG_SYSLOG> - messages generated internally by B<syslogd>

=item *

C<LOG_USER> (default) - generic user-level messages

=item *

C<LOG_UUCP> - UUCP subsystem

=back


=head2 Levels

=over 4

=item *

C<LOG_EMERG> - system is unusable

=item *

C<LOG_ALERT> - action must be taken immediately

=item *

C<LOG_CRIT> - critical conditions

=item *

C<LOG_ERR> - error conditions

=item *

C<LOG_WARNING> - warning conditions

=item *

C<LOG_NOTICE> - normal, but significant, condition

=item *

C<LOG_INFO> - informational message

=item *

C<LOG_DEBUG> - debug-level message

=back


=head1 DIAGNOSTICS

=over

=item C<Invalid argument passed to setlogsock>

B<(F)> You gave C<setlogsock()> an invalid value for C<$sock_type>. 

=item C<eventlog passed to setlogsock, but no Win32 API available>

B<(W)> You asked C<setlogsock()> to use the Win32 event logger but the 
operating system running the program isn't Win32 or does not provides Win32
compatible facilities.

=item C<no connection to syslog available>

B<(F)> C<syslog()> failed to connect to the specified socket.

=item C<stream passed to setlogsock, but %s is not writable>

B<(W)> You asked C<setlogsock()> to use a stream socket, but the given 
path is not writable. 

=item C<stream passed to setlogsock, but could not find any device>

B<(W)> You asked C<setlogsock()> to use a stream socket, but didn't 
provide a path, and C<Sys::Syslog> was unable to find an appropriate one.

=item C<tcp passed to setlogsock, but tcp service unavailable>

B<(W)> You asked C<setlogsock()> to use a TCP socket, but the service 
is not available on the system. 

=item C<syslog: expecting argument %s>

B<(F)> You forgot to give C<syslog()> the indicated argument.

=item C<syslog: invalid level/facility: %s>

B<(F)> You specified an invalid level or facility.

=item C<syslog: too many levels given: %s>

B<(F)> You specified too many levels. 

=item C<syslog: too many facilities given: %s>

B<(F)> You specified too many facilities. 

=item C<syslog: level must be given>

B<(F)> You forgot to specify a level.

=item C<udp passed to setlogsock, but udp service unavailable>

B<(W)> You asked C<setlogsock()> to use a UDP socket, but the service 
is not available on the system. 

=item C<unix passed to setlogsock, but path not available>

B<(W)> You asked C<setlogsock()> to use a UNIX socket, but C<Sys::Syslog> 
was unable to find an appropriate an appropriate device.

=back


=head1 SEE ALSO

=head2 Manual Pages

L<syslog(3)>

SUSv3 issue 6, IEEE Std 1003.1, 2004 edition, 
L<http://www.opengroup.org/onlinepubs/000095399/basedefs/syslog.h.html>

GNU C Library documentation on syslog, 
L<http://www.gnu.org/software/libc/manual/html_node/Syslog.html>

Solaris 10 documentation on syslog, 
L<http://docs.sun.com/app/docs/doc/816-5168/6mbb3hruo?a=view>

IRIX 6.4 documentation on syslog,
L<http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0640&db=man&fname=3c+syslog>

AIX 5L 5.3 documentation on syslog, 
L<http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf2/syslog.htm>

HP-UX 11i documentation on syslog, 
L<http://docs.hp.com/en/B9106-90010/syslog.3C.html>

Tru64 5.1 documentation on syslog, 
L<http://h30097.www3.hp.com/docs/base_doc/DOCUMENTATION/V51_HTML/MAN/MAN3/0193____.HTM>

Stratus VOS 15.1, 
L<http://stratadoc.stratus.com/vos/15.1.1/r502-01/wwhelp/wwhimpl/js/html/wwhelp.htm?context=r502-01&file=ch5r502-01bi.html>

=head2 RFCs

I<RFC 3164 - The BSD syslog Protocol>, L<http://www.faqs.org/rfcs/rfc3164.html>
-- Please note that this is an informational RFC, and therefore does not 
specify a standard of any kind.

I<RFC 3195 - Reliable Delivery for syslog>, L<http://www.faqs.org/rfcs/rfc3195.html>

=head2 Articles

I<Syslogging with Perl>, L<http://lexington.pm.org/meetings/022001.html>

=head2 Event Log

Windows Event Log,
L<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wes/wes/windows_event_log.asp>


=head1 AUTHORS & ACKNOWLEDGEMENTS

Tom Christiansen E<lt>F<tchrist (at) perl.com>E<gt> and Larry Wall
E<lt>F<larry (at) wall.org>E<gt>.

UNIX domain sockets added by Sean Robinson
E<lt>F<robinson_s (at) sc.maricopa.edu>E<gt> with support from Tim Bunce 
E<lt>F<Tim.Bunce (at) ig.co.uk>E<gt> and the C<perl5-porters> mailing list.

Dependency on F<syslog.ph> replaced with XS code by Tom Hughes
E<lt>F<tom (at) compton.nu>E<gt>.

Code for C<constant()>s regenerated by Nicholas Clark E<lt>F<nick (at) ccl4.org>E<gt>.

Failover to different communication modes by Nick Williams
E<lt>F<Nick.Williams (at) morganstanley.com>E<gt>.

Extracted from core distribution for publishing on the CPAN by 
SE<eacute>bastien Aperghis-Tramoni E<lt>sebastien (at) aperghis.netE<gt>.

XS code for using native C functions borrowed from C<L<Unix::Syslog>>, 
written by Marcus Harnisch E<lt>F<marcus.harnisch (at) gmx.net>E<gt>.

Yves Orton suggested and helped for making C<Sys::Syslog> use the native 
event logger under Win32 systems.

Jerry D. Hedden and Reini Urban provided greatly appreciated help to 
debug and polish C<Sys::Syslog> under Cygwin.


=head1 BUGS

Please report any bugs or feature requests to
C<bug-sys-syslog (at) rt.cpan.org>, or through the web interface at
L<http://rt.cpan.org/Public/Dist/Display.html?Name=Sys-Syslog>.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.


=head1 SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Sys::Syslog

You can also look for information at:

=over 4

=item * AnnoCPAN: Annotated CPAN documentation

L<http://annocpan.org/dist/Sys-Syslog>

=item * CPAN Ratings

L<http://cpanratings.perl.org/d/Sys-Syslog>

=item * RT: CPAN's request tracker

L<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Sys-Syslog>

=item * Search CPAN

L<http://search.cpan.org/dist/Sys-Syslog/>

=item * Kobes' CPAN Search

L<http://cpan.uwinnipeg.ca/dist/Sys-Syslog>

=item * Perl Documentation

L<http://perldoc.perl.org/Sys/Syslog.html>

=back


=head1 COPYRIGHT

Copyright (C) 1990-2007 by Larry Wall and others.


=head1 LICENSE

This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=cut

=begin comment

Notes for the future maintainer (even if it's still me..)
- - - - - - - - - - - - - - - - - - - - - - - - - - - - -

Using Google Code Search, I search who on Earth was relying on $host being 
public. It found 5 hits: 

* First was inside Indigo Star Perl2exe documentation. Just an old version 
of Sys::Syslog. 


* One real hit was inside DalWeathDB, a weather related program. It simply 
does a 

    $Sys::Syslog::host = '127.0.0.1';

- L<http://www.gallistel.net/nparker/weather/code/>


* Two hits were in TPC, a fax server thingy. It does a 

    $Sys::Syslog::host = $TPC::LOGHOST;

but also has this strange piece of code:

    # work around perl5.003 bug
    sub Sys::Syslog::hostname {}

I don't know what bug the author referred to.

- L<http://www.tpc.int/>
- L<ftp://ftp.tpc.int/tpc/server/UNIX/>
- L<ftp://ftp-usa.tpc.int/pub/tpc/server/UNIX/>


* Last hit was in Filefix, which seems to be a FIDOnet mail program (!).
This one does not use $host, but has the following piece of code:

    sub Sys::Syslog::hostname
    {
        use Sys::Hostname;
        return hostname;
    }

I guess this was a more elaborate form of the previous bit, maybe because 
of a bug in Sys::Syslog back then?

- L<ftp://ftp.kiae.su/pub/unix/fido/>


Links
-----
II12021: SYSLOGD HOWTO TCPIPINFO (z/OS, OS/390, MVS)
- L<http://www-1.ibm.com/support/docview.wss?uid=isg1II12021>

Getting the most out of the Event Viewer
- L<http://www.codeproject.com/dotnet/evtvwr.asp?print=true>

Log events to the Windows NT Event Log with JNI
- L<http://www.javaworld.com/javaworld/jw-09-2001/jw-0928-ntmessages.html>

=end comment