


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


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

VERSION
       Version 0.27

SYNOPSIS
           use Sys::Syslog;                          # all except setlogsock(), or:
           use Sys::Syslog qw(:DEFAULT setlogsock);  # default set, plus setlogsock()
           use Sys::Syslog qw(:standard :macros);    # standard functions, plus 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).

       You can find a kind of FAQ in "THE RULES OF SYS::SYSLOG".
       Please read it before coding, and again before asking
       questions.

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



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           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   "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   "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.

           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).



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           $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 "WARNIN" 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

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

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

           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) );




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           Log all messages up to debug:

               setlogmask( LOG_UPTO(LOG_DEBUG) );

       setlogsock($sock_type)
       setlogsock($sock_type, $stream_location) (added in Perl
       5.004_02)
       setlogsock($sock_type, $stream_location, $sock_timeout)
       (added in 0.25)
           Sets the socket type to be used for the next call to
           "openlog()" or "syslog()" and returns true on success,
           "undef" on failure. 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. If
               defined, the second parameter is used as a
               hostname to connect to.

           o   "udp" - connect to a UDP socket, on the
               "syslog/udp" service.  If defined, the second
               parameter is used as a hostname to connect to, and
               the third parameter as the timeout used to check
               for UDP response.

           o   "inet" - connect to an INET socket, either TCP or
               UDP, tried in that order.  If defined, the second
               parameter is used as a hostname to connect to.

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

           o   "stream" - connect to the stream indicated by the
               pathname provided as the optional second
               parameter, or, if omitted, to /dev/conslog.  For
               example Solaris and IRIX system may prefer
               "stream" instead of "unix".

           o   "pipe" - connect to the named pipe indicated by
               the pathname provided as the optional second
               parameter, 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).

           o   "console" - send messages directly to the console,



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               as for the "cons" option of "openlog()".

           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 "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");

           Select 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 occurence 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.



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       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



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


       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



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       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.




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       "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.

SEE ALSO
   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>





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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



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


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

       o   RT: CPAN's request tracker

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

       o   Search CPAN

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

       o   Kobes' CPAN Search

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

       o   Perl Documentation

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

COPYRIGHT
       Copyright (C) 1990-2008 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.

































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