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Sys::Syslog - Perl interface to the UNIX syslog(3) calls
Version 0.13
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
setlogsock $sock_type;
openlog $ident, $logopt, $facility; # don't forget this
syslog $priority, $format, @args;
$oldmask = setlogmask $mask_priority;
closelog;
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).
Sys::Syslog exports the following Exporter tags:
:standard exports the standard syslog(3) functions:
openlog closelog setlogmask syslog
:extended exports the Perl specific functions for syslog(3):
setlogsock
:macros exports the symbols corresponding to most of your syslog(3)
macros. See CONSTANTS for the supported constants and their meaning.
By default, Sys::Syslog exports the symbols from the :standard tag.
Opens the syslog.
$ident is prepended to every message. $logopt contains zero or
more of the words pid, ndelay, nowait. The cons option is
ignored, since the failover mechanism will drop down to the console
automatically if all other media fail. $facility specifies the
part of the system to report about, for example LOG_USER or LOG_LOCAL0:
see your syslog(3) documentation for the facilities available in
your system. Facility can be given as a string or a numeric macro.
This function will croak if it can't connect to the syslog daemon.
Note that openlog() now takes three arguments, just like openlog(3).
You should use openlog() before calling syslog().
Options
ndelay - Open the connection immediately (normally, the connection is
opened when the first message is logged).
nowait - Don't wait for child processes that may have been created
while logging the message. (The GNU C library does not create a child
process, so this option has no effect on Linux.)
pid - Include PID with each message.
Examples
Open the syslog with options ndelay and pid, and with facility LOCAL0:
openlog($name, "ndelay,pid", "local0");
Same thing, but this time using the macro corresponding to LOCAL0:
openlog($name, "ndelay,pid", LOG_LOCAL0);
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.
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
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.
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.
Examples
Only log errors:
setlogmask(LOG_ERR);
Log critical messages, errors and warnings:
setlogmask(LOG_CRIT|LOG_ERR|LOG_WARNING);
Sets the socket type to be used for the next call to
openlog() or syslog() and returns true on success,
undef on failure.
A value of "unix" will connect to the UNIX domain socket (in some
systems a character special device) returned by the _PATH_LOG macro
(if your system defines it), or /dev/log or /dev/conslog,
whatever is writable. A value of 'stream' will connect to the stream
indicated by the pathname provided as the optional second parameter.
(For example Solaris and IRIX require "stream" instead of "unix".)
A value of "inet" will connect to an INET socket (either tcp or udp,
tried in that order) returned by getservbyname(). "tcp" and "udp" can
also be given as values. The value "console" will send messages
directly to the console, as for the "cons" option in the logopts in
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 sock_types which are attempted in order.
The default is to try tcp, udp, unix, stream, console.
Giving an invalid value for $sock_type will croak.
Closes the log file and return true on success.
openlog($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');
setlogsock('unix');
openlog("$program $$", 'ndelay', 'user');
syslog('notice', 'fooprogram: this is really done');
setlogsock('inet');
$! = 55;
syslog('info', 'problem was %m'); # %m == $! in syslog(3)
# Log to UDP port on $remotehost instead of logging locally
setlogsock('udp');
$Sys::Syslog::host = $remotehost;
openlog($program, 'ndelay', 'user');
syslog('info', 'something happened over here');
LOG_AUTH - security/authorization messages
LOG_AUTHPRIV - security/authorization messages (private)
LOG_CRON - clock daemon (cron and at)
LOG_DAEMON - system daemons without separate facility value
LOG_FTP - ftp daemon
LOG_KERN - kernel messages
LOG_LOCAL0 through LOG_LOCAL7 - reserved for local use
LOG_LPR - line printer subsystem
LOG_MAIL - mail subsystem
LOG_NEWS - USENET news subsystem
LOG_SYSLOG - messages generated internally by syslogd
LOG_USER (default) - generic user-level messages
LOG_UUCP - UUCP subsystem
LOG_EMERG - system is unusable
LOG_ALERT - action must be taken immediately
LOG_CRIT - critical conditions
LOG_ERR - error conditions
LOG_WARNING - warning conditions
LOG_NOTICE - normal, but significant, condition
LOG_INFO - informational message
LOG_DEBUG - debug-level message
(F) You gave setlogsock() an invalid value for $sock_type.
(F) syslog() failed to connect to the specified socket.
(W) You asked setlogsock() to use a stream socket, but the given
path is not writable.
(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.
(W) You asked setlogsock() to use a TCP socket, but the service
is not available on the system.
(F) You forgot to give syslog() the indicated argument.
(F) You specified an invalid level or facility, like LOG_KERN
(which is reserved to the kernel).
(F) You specified too many levels.
(F) You specified too many facilities.
(F) You forgot to specify a level.
(W) You asked setlogsock() to use a UDP socket, but the service
is not available on the system.
(W) You asked setlogsock() to use a UNIX socket, but Sys::Syslog
was unable to find an appropriate an appropriate device.
Syslogging with Perl, http://lexington.pm.org/meetings/022001.html
Tom Christiansen <tchrist@perl.com> and Larry Wall <larry@wall.org>.
UNIX domain sockets added by Sean Robinson
<robinson_s@sc.maricopa.edu> with support from Tim Bunce
<Tim.Bunce@ig.co.uk> and the perl5-porters mailing list.
Dependency on syslog.ph replaced with XS code by Tom Hughes <tom@compton.nu>.
Code for constant()s regenerated by Nicholas Clark <nick@ccl4.org>.
Failover to different communication modes by Nick Williams <Nick.Williams@morganstanley.com>.
Extracted from core distribution for publishing on the CPAN by Sébastien Aperghis-Tramoni <sebastien@aperghis.net>.
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/NoAuth/ReportBug.html.
I will be notified, and then you'll automatically be notified of progress on
your bug as I make changes.
You can find documentation for this module with the perldoc command.
perldoc Sys::Syslog
You can also look for information at:
This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.