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Sys::Syslog(3pm)       Perl Programmers Reference Guide       Sys::Syslog(3pm)




NAME

       Sys::Syslog - Perl interface to the UNIX syslog(3) calls


VERSION

       This is the documentation of version 0.33


SYNOPSIS

           use Sys::Syslog;                        # all except setlogsock()
           use Sys::Syslog qw(:standard :macros);  # standard functions & macros

           openlog($ident, $logopt, $facility);    # don't forget this
           syslog($priority, $format, @args);
           $oldmask = setlogmask($mask_priority);
           closelog();


DESCRIPTION

       "Sys::Syslog" is an interface to the UNIX syslog(3) program.  Call
       "syslog()" with a string priority and a list of "printf()" args just
       like syslog(3).


EXPORTS

       "Sys::Syslog" exports the following "Exporter" tags:

       o   ":standard" exports the standard syslog(3) functions:

               openlog closelog setlogmask syslog

       o   ":extended" exports the Perl specific functions for syslog(3):

               setlogsock

       o   ":macros" exports the symbols corresponding to most of your
           syslog(3) macros and the "LOG_UPTO()" and "LOG_MASK()" functions.
           See "CONSTANTS" for the supported constants and their meaning.

       By default, "Sys::Syslog" exports the symbols from the ":standard" tag.


FUNCTIONS

       openlog($ident, $logopt, $facility)
           Opens the syslog.  $ident is prepended to every message.  $logopt
           contains zero or more of the options detailed below.  $facility
           specifies the part of the system to report about, for example
           "LOG_USER" or "LOG_LOCAL0": see "Facilities" for a list of well-
           known facilities, and your syslog(3) documentation for the
           facilities available in your system.  Check "SEE ALSO" for useful
           links. Facility can be given as a string or a numeric macro.

           This function will croak if it can't connect to the syslog daemon.

           Note that "openlog()" now takes three arguments, just like
           openlog(3).

           You should use "openlog()" before calling "syslog()".

           Options

           o   "cons" - This option is ignored, since the failover mechanism
               will drop down to the console automatically if all other media
               fail.

           o   "ndelay" - Open the connection immediately (normally, the
               connection is opened when the first message is logged).

           o   "noeol" - When set to true, no end of line character ("\n")
               will be appended to the message. This can be useful for some
               buggy syslog daemons.

           o   "nofatal" - When set to true, "openlog()" and "syslog()" will
               only emit warnings instead of dying if the connection to the
               syslog can't be established.

           o   "nonul" - When set to true, no "NUL" character ("\0") will be
               appended to the message. This can be useful for some buggy
               syslog daemons.

           o   "nowait" - Don't wait for child processes that may have been
               created while logging the message.  (The GNU C library does not
               create a child process, so this option has no effect on Linux.)

           o   "perror" - Write the message to standard error output as well
               to the system log (added in "Sys::Syslog" 0.22).

           o   "pid" - Include PID with each message.

           Examples

           Open the syslog with options "ndelay" and "pid", and with facility
           "LOCAL0":

               openlog($name, "ndelay,pid", "local0");

           Same thing, but this time using the macro corresponding to
           "LOCAL0":

               openlog($name, "ndelay,pid", LOG_LOCAL0);

       syslog($priority, $message)
       syslog($priority, $format, @args)
           If $priority permits, logs $message or "sprintf($format, @args)"
           with the addition that %m in $message or $format is replaced with
           "$!" (the latest error message).

           $priority can specify a level, or a level and a facility.  Levels
           and facilities can be given as strings or as macros.  When using
           the "eventlog" mechanism, priorities "DEBUG" and "INFO" are mapped
           to event type "informational", "NOTICE" and "WARNING" to "warning"
           and "ERR" to "EMERG" to "error".

           If you didn't use "openlog()" before using "syslog()", "syslog()"
           will try to guess the $ident by extracting the shortest prefix of
           $format that ends in a ":".

           Examples

               # informational level
               syslog("info", $message);
               syslog(LOG_INFO, $message);

               # information level, Local0 facility
               syslog("info|local0", $message);
               syslog(LOG_INFO|LOG_LOCAL0, $message);

           Note
               "Sys::Syslog" version v0.07 and older passed the $message as
               the formatting string to "sprintf()" even when no formatting
               arguments were provided.  If the code calling "syslog()" might
               execute with older versions of this module, make sure to call
               the function as "syslog($priority, "%s", $message)" instead of
               "syslog($priority, $message)".  This protects against hostile
               formatting sequences that might show up if $message contains
               tainted data.

       setlogmask($mask_priority)
           Sets the log mask for the current process to $mask_priority and
           returns the old mask.  If the mask argument is 0, the current log
           mask is not modified.  See "Levels" for the list of available
           levels.  You can use the "LOG_UPTO()" function to allow all levels
           up to a given priority (but it only accept the numeric macros as
           arguments).

           Examples

           Only log errors:

               setlogmask( LOG_MASK(LOG_ERR) );

           Log everything except informational messages:

               setlogmask( ~(LOG_MASK(LOG_INFO)) );

           Log critical messages, errors and warnings:

               setlogmask( LOG_MASK(LOG_CRIT)
                         | LOG_MASK(LOG_ERR)
                         | LOG_MASK(LOG_WARNING) );

           Log all messages up to debug:

               setlogmask( LOG_UPTO(LOG_DEBUG) );

       setlogsock()
           Sets the socket type and options to be used for the next call to
           "openlog()" or "syslog()".  Returns true on success, "undef" on
           failure.

           Being Perl-specific, this function has evolved along time.  It can
           currently be called as follow:

           o   "setlogsock($sock_type)"

           o   "setlogsock($sock_type, $stream_location)" (added in Perl
               5.004_02)

           o   "setlogsock($sock_type, $stream_location, $sock_timeout)"
               (added in "Sys::Syslog" 0.25)

           o   "setlogsock(\%options)" (added in "Sys::Syslog" 0.28)

           The available options are:

           o   "type" - equivalent to $sock_type, selects the socket type (or
               "mechanism").  An array reference can be passed to specify
               several mechanisms to try, in the given order.

           o   "path" - equivalent to $stream_location, sets the stream
               location.  Defaults to standard Unix location, or "_PATH_LOG".

           o   "timeout" - equivalent to $sock_timeout, sets the socket
               timeout in seconds.  Defaults to 0 on all systems except
               Mac OS X where it is set to 0.25 sec.

           o   "host" - sets the hostname to send the messages to.  Defaults
               to the local host.

           o   "port" - sets the TCP or UDP port to connect to.  Defaults to
               the first standard syslog port available on the system.

           The available mechanisms are:

           o   "native" - use the native C functions from your syslog(3)
               library (added in "Sys::Syslog" 0.15).

           o   "eventlog" - send messages to the Win32 events logger (Win32
               only; added in "Sys::Syslog" 0.19).

           o   "tcp" - connect to a TCP socket, on the "syslog/tcp" or
               "syslogng/tcp" service.  See also the "host", "port" and
               "timeout" options.

           o   "udp" - connect to a UDP socket, on the "syslog/udp" service.
               See also the "host", "port" and "timeout" options.

           o   "inet" - connect to an INET socket, either TCP or UDP, tried in
               that order.  See also the "host", "port" and "timeout" options.

           o   "unix" - connect to a UNIX domain socket (in some systems a
               character special device).  The name of that socket is given by
               the "path" option or, if omitted, the value returned by the
               "_PATH_LOG" macro (if your system defines it), /dev/log or
               /dev/conslog, whichever is writable.

           o   "stream" - connect to the stream indicated by the "path"
               option, or, if omitted, the value returned by the "_PATH_LOG"
               macro (if your system defines it), /dev/log or /dev/conslog,
               whichever is writable.  For example Solaris and IRIX system may
               prefer "stream" instead of "unix".

           o   "pipe" - connect to the named pipe indicated by the "path"
               option, or, if omitted, to the value returned by the
               "_PATH_LOG" macro (if your system defines it), or /dev/log
               (added in "Sys::Syslog" 0.21).  HP-UX is a system which uses
               such a named pipe.

           o   "console" - send messages directly to the console, as for the
               "cons" option of "openlog()".

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

           Giving an invalid value for $sock_type will "croak".

           Examples

           Select the UDP socket mechanism:

               setlogsock("udp");

           Send messages using the TCP socket mechanism on a custom port:

               setlogsock({ type => "tcp", port => 2486 });

           Send messages to a remote host using the TCP socket mechanism:

               setlogsock({ type => "tcp", host => $loghost });

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

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

           Note
               Now that the "native" mechanism is supported by "Sys::Syslog"
               and selected by default, the use of the "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
               "setlogsock("unix")", are advised to remove any occurrence of
               it unless they specifically want to use a given mechanism (like
               TCP or UDP to connect to a remote host).

       closelog()
           Closes the log file and returns true on success.


THE RULES OF SYS::SYSLOG

       The First Rule of Sys::Syslog is: You do not call "setlogsock".

       The Second Rule of Sys::Syslog is: You do not call "setlogsock".

       The Third Rule of Sys::Syslog is: The program crashes, "die"s, calls
       "closelog", the log is over.

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

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

       The Sixth Rule of Sys::Syslog is: No "syslog" before "openlog".

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

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


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 %m:

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

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

           setlogsock("udp", $remotehost);
           openlog($program, 'ndelay', 'user');
           syslog('info', 'something happened over here');


CONSTANTS

   Facilities
       o   "LOG_AUDIT" - audit daemon (IRIX); falls back to "LOG_AUTH"

       o   "LOG_AUTH" - security/authorization messages

       o   "LOG_AUTHPRIV" - security/authorization messages (private)

       o   "LOG_CONSOLE" - "/dev/console" output (FreeBSD); falls back to
           "LOG_USER"

       o   "LOG_CRON" - clock daemons (cron and at)

       o   "LOG_DAEMON" - system daemons without separate facility value

       o   "LOG_FTP" - FTP daemon

       o   "LOG_KERN" - kernel messages

       o   "LOG_INSTALL" - installer subsystem (Mac OS X); falls back to
           "LOG_USER"

       o   "LOG_LAUNCHD" - launchd - general bootstrap daemon (Mac OS X);
           falls back to "LOG_DAEMON"

       o   "LOG_LFMT" - logalert facility; falls back to "LOG_USER"

       o   "LOG_LOCAL0" through "LOG_LOCAL7" - reserved for local use

       o   "LOG_LPR" - line printer subsystem

       o   "LOG_MAIL" - mail subsystem

       o   "LOG_NETINFO" - NetInfo subsystem (Mac OS X); falls back to
           "LOG_DAEMON"

       o   "LOG_NEWS" - USENET news subsystem

       o   "LOG_NTP" - NTP subsystem (FreeBSD, NetBSD); falls back to
           "LOG_DAEMON"

       o   "LOG_RAS" - Remote Access Service (VPN / PPP) (Mac OS X); falls
           back to "LOG_AUTH"

       o   "LOG_REMOTEAUTH" - remote authentication/authorization (Mac OS X);
           falls back to "LOG_AUTH"

       o   "LOG_SECURITY" - security subsystems (firewalling, etc.) (FreeBSD);
           falls back to "LOG_AUTH"

       o   "LOG_SYSLOG" - messages generated internally by syslogd

       o   "LOG_USER" (default) - generic user-level messages

       o   "LOG_UUCP" - UUCP subsystem

   Levels
       o   "LOG_EMERG" - system is unusable

       o   "LOG_ALERT" - action must be taken immediately

       o   "LOG_CRIT" - critical conditions

       o   "LOG_ERR" - error conditions

       o   "LOG_WARNING" - warning conditions

       o   "LOG_NOTICE" - normal, but significant, condition

       o   "LOG_INFO" - informational message

       o   "LOG_DEBUG" - debug-level message


DIAGNOSTICS

       "Invalid argument passed to setlogsock"
           (F) You gave "setlogsock()" an invalid value for $sock_type.

       "eventlog passed to setlogsock, but no Win32 API available"
           (W) You asked "setlogsock()" to use the Win32 event logger but the
           operating system running the program isn't Win32 or does not
           provides Win32 compatible facilities.

       "no connection to syslog available"
           (F) "syslog()" failed to connect to the specified socket.

       "stream passed to setlogsock, but %s is not writable"
           (W) You asked "setlogsock()" to use a stream socket, but the given
           path is not writable.

       "stream passed to setlogsock, but could not find any device"
           (W) You asked "setlogsock()" to use a stream socket, but didn't
           provide a path, and "Sys::Syslog" was unable to find an appropriate
           one.

       "tcp passed to setlogsock, but tcp service unavailable"
           (W) You asked "setlogsock()" to use a TCP socket, but the service
           is not available on the system.

       "syslog: expecting argument %s"
           (F) You forgot to give "syslog()" the indicated argument.

       "syslog: invalid level/facility: %s"
           (F) You specified an invalid level or facility.

       "syslog: too many levels given: %s"
           (F) You specified too many levels.

       "syslog: too many facilities given: %s"
           (F) You specified too many facilities.

       "syslog: level must be given"
           (F) You forgot to specify a level.

       "udp passed to setlogsock, but udp service unavailable"
           (W) You asked "setlogsock()" to use a UDP socket, but the service
           is not available on the system.

       "unix passed to setlogsock, but path not available"
           (W) You asked "setlogsock()" to use a UNIX socket, but
           "Sys::Syslog" was unable to find an appropriate an appropriate
           device.


HISTORY

       "Sys::Syslog" is a core module, part of the standard Perl distribution
       since 1990.  At this time, modules as we know them didn't exist, the
       Perl library was a collection of .pl files, and the one for sending
       syslog messages with was simply lib/syslog.pl, included with Perl 3.0.
       It was converted as a module with Perl 5.0, but had a version number
       only starting with Perl 5.6.  Here is a small table with the matching
       Perl and "Sys::Syslog" versions.

           Sys::Syslog     Perl
           -----------     ----
              undef        5.0.0 ~ 5.5.4
              0.01         5.6.*
              0.03         5.8.0
              0.04         5.8.1, 5.8.2, 5.8.3
              0.05         5.8.4, 5.8.5, 5.8.6
              0.06         5.8.7
              0.13         5.8.8
              0.22         5.10.0
              0.27         5.8.9, 5.10.1 ~ 5.14.2
              0.29         5.16.0, 5.16.1


SEE ALSO

   Other modules
       Log::Log4perl(3) - Perl implementation of the Log4j API

       Log::Dispatch(3) - Dispatches messages to one or more outputs

       Log::Report(3) - Report a problem, with exceptions and language support

   Manual Pages
       syslog(3)

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

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

       Solaris 10 documentation on syslog,
       <http://docs.sun.com/app/docs/doc/816-5168/syslog-3c?a=view>

       Mac OS X documentation on syslog,
       <http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/syslog.3.html>

       IRIX 6.5 documentation on syslog,
       <http://techpubs.sgi.com/library/tpl/cgi-bin/getdoc.cgi?coll=0650&db=man&fname=3c+syslog>

       AIX 5L 5.3 documentation on syslog,
       <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,
       <http://docs.hp.com/en/B2355-60130/syslog.3C.html>

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

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

   RFCs
       RFC 3164 - The BSD syslog Protocol,
       <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.

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

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

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


AUTHORS & ACKNOWLEDGEMENTS

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

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

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

       Code for "constant()"s regenerated by Nicholas Clark <nick (at)
       ccl4.org>.

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

       Extracted from core distribution for publishing on the CPAN by
       Sebastien Aperghis-Tramoni <sebastien (at) aperghis.net>.

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

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

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


BUGS

       Please report any bugs or feature requests to "bug-sys-syslog (at)
       rt.cpan.org", or through the web interface at
       <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.


SUPPORT

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

           perldoc Sys::Syslog

       You can also look for information at:

       o   AnnoCPAN: Annotated CPAN documentation

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

       o   CPAN Ratings

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

       o   RT: CPAN's request tracker

           <http://rt.cpan.org/Dist/Display.html?Queue=Sys-Syslog>

       o   Search CPAN

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

       o   MetaCPAN

           <https://metacpan.org/module/Sys::Syslog>

       o   Perl Documentation

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


COPYRIGHT

       Copyright (C) 1990-2012 by Larry Wall and others.


LICENSE

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



perl v5.24.0                      2016-02-05                  Sys::Syslog(3pm)

perl 5.24 - Generated Wed Nov 23 16:03:08 CST 2016
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