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package Sys::Syslog;
require 5.000;
require Exporter;
use Carp;
@ISA = qw(Exporter);
@EXPORT = qw(openlog closelog setlogmask syslog);
use Socket;
# adapted from syslog.pl
#
# Tom Christiansen <tchrist@convex.com>
# modified to use sockets by Larry Wall <lwall@jpl-devvax.jpl.nasa.gov>
# NOTE: openlog now takes three arguments, just like openlog(3)
=head1 NAME
Sys::Syslog, openlog, closelog, setlogmask, syslog - Perl interface to the UNIX syslog(3) calls
=head1 SYNOPSIS
use Sys::Syslog;
openlog $ident, $logopt, $facility;
syslog $priority, $mask, $format, @args;
$oldmask = setlogmask $mask_priority;
closelog;
=head1 DESCRIPTION
Sys::Syslog is an interface to the UNIX C<syslog(3)> program.
Call C<syslog()> with a string priority and a list of C<printf()> args
just like C<syslog(3)>.
Syslog provides the functions:
=over
=item openlog $ident, $logopt, $facility
I<$ident> is prepended to every message.
I<$logopt> contains one or more of the words I<pid>, I<ndelay>, I<cons>, I<nowait>.
I<$facility> specifies the part of the system
=item syslog $priority, $mask, $format, @args
If I<$priority> and I<$mask> permit, logs I<($format, @args)>
printed as by C<printf(3V)>, with the addition that I<%m>
is replaced with C<"$!"> (the latest error message).
=item setlogmask $mask_priority
Sets log mask I<$mask_priority> and returns the old mask.
=item closelog
Closes the log file.
=back
Note that C<openlog> now takes three arguments, just like C<openlog(3)>.
=head1 EXAMPLES
openlog($program, 'cons,pid', 'user');
syslog('info', 'this is another test');
syslog('mail|warning', 'this is a better test: %d', time);
closelog();
syslog('debug', 'this is the last test');
openlog("$program $$", 'ndelay', 'user');
syslog('notice', 'fooprogram: this is really done');
$! = 55;
syslog('info', 'problem was %m'); # %m == $! in syslog(3)
=head1 DEPENDENCIES
B<Sys::Syslog> needs F<syslog.ph>, which can be created with C<h2ph>.
=head1 SEE ALSO
L<syslog(3)>
=head1 AUTHOR
Tom Christiansen E<lt>F<tchrist@perl.com>E<gt> and Larry Wall E<lt>F<lwall@sems.com>E<gt>
=cut
$host = hostname() unless $host; # set $Syslog::host to change
require 'syslog.ph';
$maskpri = &LOG_UPTO(&LOG_DEBUG);
sub openlog {
($ident, $logopt, $facility) = @_; # package vars
$lo_pid = $logopt =~ /\bpid\b/;
$lo_ndelay = $logopt =~ /\bndelay\b/;
$lo_cons = $logopt =~ /\bcons\b/;
$lo_nowait = $logopt =~ /\bnowait\b/;
&connect if $lo_ndelay;
}
sub closelog {
$facility = $ident = '';
&disconnect;
}
sub setlogmask {
local($oldmask) = $maskpri;
$maskpri = shift;
$oldmask;
}
sub syslog {
local($priority) = shift;
local($mask) = shift;
local($message, $whoami);
local(@words, $num, $numpri, $numfac, $sum);
local($facility) = $facility; # may need to change temporarily.
croak "syslog: expected both priority and mask" unless $mask && $priority;
@words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
undef $numpri;
undef $numfac;
foreach (@words) {
$num = &xlate($_); # Translate word to number.
if (/^kern$/ || $num < 0) {
croak "syslog: invalid level/facility: $_";
}
elsif ($num <= &LOG_PRIMASK) {
croak "syslog: too many levels given: $_" if defined($numpri);
$numpri = $num;
return 0 unless &LOG_MASK($numpri) & $maskpri;
}
else {
croak "syslog: too many facilities given: $_" if defined($numfac);
$facility = $_;
$numfac = $num;
}
}
croak "syslog: level must be given" unless defined($numpri);
if (!defined($numfac)) { # Facility not specified in this call.
$facility = 'user' unless $facility;
$numfac = &xlate($facility);
}
&connect unless $connected;
$whoami = $ident;
if (!$ident && $mask =~ /^(\S.*):\s?(.*)/) {
$whoami = $1;
$mask = $2;
}
unless ($whoami) {
($whoami = getlogin) ||
($whoami = getpwuid($<)) ||
($whoami = 'syslog');
}
$whoami .= "[$$]" if $lo_pid;
$mask =~ s/%m/$!/g;
$mask .= "\n" unless $mask =~ /\n$/;
$message = sprintf ($mask, @_);
$sum = $numpri + $numfac;
unless (send(SYSLOG,"<$sum>$whoami: $message",0)) {
if ($lo_cons) {
if ($pid = fork) {
unless ($lo_nowait) {
$died = waitpid($pid, 0);
}
}
else {
open(CONS,">/dev/console");
print CONS "<$facility.$priority>$whoami: $message\r";
exit if defined $pid; # if fork failed, we're parent
close CONS;
}
}
}
}
sub xlate {
local($name) = @_;
$name =~ y/a-z/A-Z/;
$name = "LOG_$name" unless $name =~ /^LOG_/;
$name = "Sys::Syslog::$name";
eval(&$name) || -1;
}
sub connect {
unless ($host) {
require Sys::Hostname;
$host = Sys::Hostname::hostname();
}
my $udp = getprotobyname('udp');
my $syslog = getservbyname('syslog','udp');
my $this = sockaddr_in($syslog, INADDR_ANY);
my $that = sockaddr_in($syslog, inet_aton($host) || croak "Can't lookup $host");
socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp) || croak "socket: $!";
connect(SYSLOG,$that) || croak "connect: $!";
local($old) = select(SYSLOG); $| = 1; select($old);
$connected = 1;
}
sub disconnect {
close SYSLOG;
$connected = 0;
}
1;
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