standard
=> [qw(openlog syslog closelog setlogmask)],
extended
=> [qw(setlogsock)],
LOG_ALERT LOG_AUTH LOG_AUTHPRIV LOG_CONS LOG_CRIT LOG_CRON
LOG_DAEMON LOG_DEBUG LOG_EMERG LOG_ERR LOG_FACMASK LOG_FTP
LOG_INFO LOG_KERN LOG_LFMT LOG_LOCAL0 LOG_LOCAL1 LOG_LOCAL2
LOG_LOCAL3 LOG_LOCAL4 LOG_LOCAL5 LOG_LOCAL6 LOG_LOCAL7 LOG_LPR
LOG_MAIL LOG_NDELAY LOG_NEWS LOG_NFACILITIES LOG_NOTICE
LOG_NOWAIT LOG_ODELAY LOG_PERROR LOG_PID LOG_PRIMASK LOG_SYSLOG
LOG_USER LOG_UUCP LOG_WARNING
@
{$EXPORT_TAGS{standard
}},
@
{$EXPORT_TAGS{extended
}},
# it would be nice to try stream/unix first, since that will be
# most efficient. However streams are dodgy - see _syslog_send_stream
my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
if ($^O
=~ /^(freebsd|linux)$/) {
@connectMethods = grep { $_ ne 'udp' } @connectMethods;
my @defaultMethods = @connectMethods;
my $current_proto = undef;
our ($connected, @fallbackMethods, $syslog_send, $host);
use POSIX
qw(strftime setlocale LC_TIME);
Sys::Syslog - Perl interface to the UNIX syslog(3) calls
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 $mask_priority;
C<Sys::Syslog> is an interface to the UNIX C<syslog(3)> program.
Call C<syslog()> with a string priority and a list of C<printf()> args
C<Sys::Syslog> exports the following C<Exporter> tags:
C<:standard> exports the standard C<syslog(3)> functions:
openlog closelog setlogmask syslog
C<:extended> exports the Perl specific functions for C<syslog(3)>:
C<:macros> exports the symbols corresponding to most of your C<syslog(3)>
macros. See L<"CONSTANTS"> for the supported constants and their meaning.
By default, C<Sys::Syslog> exports the symbols from the C<:standard> tag.
=item B<openlog($ident, $logopt, $facility)>
C<$ident> is prepended to every message. C<$logopt> contains zero or
more of the words C<pid>, C<ndelay>, C<nowait>. The C<cons> option is
ignored, since the failover mechanism will drop down to the console
automatically if all other media fail. C<$facility> specifies the
part of the system to report about, for example C<LOG_USER> or C<LOG_LOCAL0>:
see your C<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 C<openlog()> now takes three arguments, just like C<openlog(3)>.
B<You should use openlog() before calling syslog().>
C<ndelay> - Open the connection immediately (normally, the connection is
opened when the first message is logged).
C<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.)
C<pid> - Include PID with each message.
Open the syslog with options C<ndelay> and C<pid>, and with facility C<LOCAL0>:
openlog($name, "ndelay,pid", "local0");
Same thing, but this time using the macro corresponding to C<LOCAL0>:
openlog($name, "ndelay,pid", LOG_LOCAL0);
=item B<syslog($priority, $message)>
=item B<syslog($priority, $format, @args)>
If C<$priority> permits, logs C<$message> or C<sprintf($format, @args)>
with the addition that C<%m> in $message or C<$format> is replaced with
C<"$!"> (the latest error message).
C<$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 C<openlog()> before using C<syslog()>, C<syslog()> will
try to guess the C<$ident> by extracting the shortest prefix of
C<$format> that ends in a C<":">.
syslog("info", $message); # informational level
syslog(LOG_INFO, $message); # informational level
syslog("info|local0", $message); # information level, Local0 facility
syslog(LOG_INFO|LOG_LOCAL0, $message); # information level, Local0 facility
C<Sys::Syslog> version v0.07 and older passed the C<$message> as the
formatting string to C<sprintf()> even when no formatting arguments
were provided. If the code calling C<syslog()> might execute with
older versions of this module, make sure to call the function as
C<syslog($priority, "%s", $message)> instead of C<syslog($priority,
$message)>. This protects against hostile formatting sequences that
might show up if $message contains tainted data.
=item B<setlogmask($mask_priority)>
Sets the log mask for the current process to C<$mask_priority> and
returns the old mask. If the mask argument is 0, the current log mask
is not modified. See L<"Levels"> for the list of available levels.
Log critical messages, errors and warnings:
setlogmask(LOG_CRIT|LOG_ERR|LOG_WARNING);
=item B<setlogsock($sock_type)>
=item B<setlogsock($sock_type, $stream_location)> (added in 5.004_02)
Sets the socket type to be used for the next call to
C<openlog()> or C<syslog()> and returns true on success,
A value of C<"unix"> will connect to the UNIX domain socket (in some
systems a character special device) returned by the C<_PATH_LOG> macro
(if your system defines it), or F</dev/log> or F</dev/conslog>,
whatever is writable. A value of 'stream' will connect to the stream
indicated by the pathname provided as the optional second parameter.
(For example Solaris and IRIX require C<"stream"> instead of C<"unix">.)
A value of C<"inet"> will connect to an INET socket (either C<tcp> or C<udp>,
tried in that order) returned by C<getservbyname()>. C<"tcp"> and C<"udp"> can
also be given as values. The value C<"console"> will send messages
directly to the console, as for the C<"cons"> option in the logopts in
A reference to an array can also be passed as the first parameter.
When this calling method is used, the array should contain a list of
sock_types which are attempted in order.
The default is to try C<tcp>, C<udp>, C<unix>, C<stream>, C<console>.
Giving an invalid value for C<$sock_type> will croak.
Closes the log file and return true on success.
openlog($program, 'cons,pid', 'user');
syslog('info', '%s', 'this is another test');
syslog('mail|warning', 'this is a better test: %d', time);
syslog('debug', 'this is the last test');
openlog("$program $$", 'ndelay', 'user');
syslog('notice', 'fooprogram: this is really done');
syslog('info', 'problem was %m'); # %m == $! in syslog(3)
# Log to UDP port on $remotehost instead of logging locally
$Sys::Syslog::host = $remotehost;
openlog($program, 'ndelay', 'user');
syslog('info', 'something happened over here');
C<LOG_AUTH> - security/authorization messages
C<LOG_AUTHPRIV> - security/authorization messages (private)
C<LOG_CRON> - clock daemon (B<cron> and B<at>)
C<LOG_DAEMON> - system daemons without separate facility value
C<LOG_KERN> - kernel messages
C<LOG_LOCAL0> through C<LOG_LOCAL7> - reserved for local use
C<LOG_LPR> - line printer subsystem
C<LOG_MAIL> - mail subsystem
C<LOG_NEWS> - USENET news subsystem
C<LOG_SYSLOG> - messages generated internally by B<syslogd>
C<LOG_USER> (default) - generic user-level messages
C<LOG_UUCP> - UUCP subsystem
C<LOG_EMERG> - system is unusable
C<LOG_ALERT> - action must be taken immediately
C<LOG_CRIT> - critical conditions
C<LOG_ERR> - error conditions
C<LOG_WARNING> - warning conditions
C<LOG_NOTICE> - normal, but significant, condition
C<LOG_INFO> - informational message
C<LOG_DEBUG> - debug-level message
=item Invalid argument passed to setlogsock
B<(F)> You gave C<setlogsock()> an invalid value for C<$sock_type>.
=item no connection to syslog available
B<(F)> C<syslog()> failed to connect to the specified socket.
=item stream passed to setlogsock, but %s is not writable
B<(W)> You asked C<setlogsock()> to use a stream socket, but the given
=item 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 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 syslog: expecting argument %s
B<(F)> You forgot to give C<syslog()> the indicated argument.
=item syslog: invalid level/facility: %s
B<(F)> You specified an invalid level or facility, like C<LOG_KERN>
(which is reserved to the kernel).
=item syslog: too many levels given: %s
B<(F)> You specified too many levels.
=item syslog: too many facilities given: %s
B<(F)> You specified too many facilities.
=item syslog: level must be given
B<(F)> You forgot to specify a level.
=item 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 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.
I<Syslogging with Perl>, L<http://lexington.pm.org/meetings/022001.html>
Tom Christiansen E<lt>F<tchrist@perl.com>E<gt> and Larry Wall
E<lt>F<larry@wall.org>E<gt>.
UNIX domain sockets added by Sean Robinson
E<lt>F<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
E<lt>F<Tim.Bunce@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@compton.nu>E<gt>.
Code for C<constant()>s regenerated by Nicholas Clark E<lt>F<nick@ccl4.org>E<gt>.
Failover to different communication modes by Nick Williams
E<lt>F<Nick.Williams@morganstanley.com>E<gt>.
Extracted from core distribution for publishing on the CPAN by
SE<eacute>bastien Aperghis-Tramoni E<lt>sebastien@aperghis.netE<gt>.
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/NoAuth/ReportBug.html?Queue=Sys-Syslog>.
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.
You can also look for information at:
=item * AnnoCPAN: Annotated CPAN documentation
L<http://annocpan.org/dist/Sys-Syslog>
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>
L<http://search.cpan.org/dist/Sys-Syslog>
This program is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
# This AUTOLOAD is used to 'autoload' constants from the constant()
($constname = $AUTOLOAD) =~ s/.*:://;
croak
"&Sys::Syslog::constant not defined" if $constname eq 'constant';
my ($error, $val) = constant
($constname);
*$AUTOLOAD = sub { $val };
XSLoader
::load
('Sys::Syslog', $VERSION);
bootstrap Sys
::Syslog
$VERSION;
our $maskpri = &LOG_UPTO
(&LOG_DEBUG
);
our ($ident, $logopt, $facility) = @_; # package vars
our $lo_pid = $logopt =~ /\bpid\b/;
our $lo_ndelay = $logopt =~ /\bndelay\b/;
our $lo_nowait = $logopt =~ /\bnowait\b/;
return 1 unless $lo_ndelay;
our $facility = our $ident = '';
$maskpri = shift unless $_[0] == 0;
&disconnect
if $connected;
@connectMethods = @defaultMethods;
if (ref $setsock eq 'ARRAY') {
@connectMethods = @
$setsock;
} elsif (lc($setsock) eq 'stream') {
unless (defined $syslog_path) {
my @try = qw(/dev/log /dev/conslog);
if (length &_PATH_LOG
) { # Undefined _PATH_LOG is "".
unshift @try, &_PATH_LOG
;
carp
"stream passed to setlogsock, but could not find any device"
unless defined $syslog_path
unless (-w
$syslog_path) {
carp
"stream passed to setlogsock, but $syslog_path is not writable";
@connectMethods = ( 'stream' );
} elsif (lc($setsock) eq 'unix') {
if (length _PATH_LOG
() && !defined $syslog_path) {
$syslog_path = _PATH_LOG
();
@connectMethods = ( 'unix' );
carp
'unix passed to setlogsock, but path not available';
} elsif (lc($setsock) eq 'tcp') {
if (getservbyname('syslog', 'tcp') || getservbyname('syslogng', 'tcp')) {
@connectMethods = ( 'tcp' );
carp
"tcp passed to setlogsock, but tcp service unavailable";
} elsif (lc($setsock) eq 'udp') {
if (getservbyname('syslog', 'udp')) {
@connectMethods = ( 'udp' );
carp
"udp passed to setlogsock, but udp service unavailable";
} elsif (lc($setsock) eq 'inet') {
@connectMethods = ( 'tcp', 'udp' );
} elsif (lc($setsock) eq 'console') {
@connectMethods = ( 'console' );
croak
"Invalid argument passed to setlogsock; must be 'stream', 'unix', 'tcp', 'udp' or 'inet'"
my (@words, $num, $numpri, $numfac, $sum);
local($facility) = $facility; # may need to change temporarily.
croak
"syslog: expecting argument \$priority" unless defined $priority;
croak
"syslog: expecting argument \$format" unless defined $mask;
@words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
$num = &xlate
($_); # Translate word to number.
if ($_ eq 'kern' || $num <= 0) {
croak
"syslog: invalid level/facility: $_"
elsif ($num <= &LOG_PRIMASK
) {
croak
"syslog: too many levels given: $_" if defined($numpri);
return 0 unless &LOG_MASK
($numpri) & $maskpri;
croak
"syslog: too many facilities given: $_" if defined($numfac);
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;
if (!$whoami && $mask =~ /^(\S.*?):\s?(.*)/) {
($whoami = getpwuid($<)) ||
$whoami .= "[$$]" if our $lo_pid;
# escape percent signs if sprintf will be called
# replace %m with $err, if preceded by an even number of percent signs
$mask =~ s/(?<!%)((?:%%)*)%m/$1$err/g;
$mask .= "\n" unless $mask =~ /\n$/;
$message = @_ ?
sprintf($mask, @_) : $mask;
$sum = $numpri + $numfac;
my $oldlocale = setlocale
(LC_TIME
);
my $timestamp = strftime
"%b %e %T", localtime;
setlocale
(LC_TIME
, $oldlocale);
my $buf = "<$sum>$timestamp $whoami: $message\0";
# it's possible that we'll get an error from sending
# (e.g. if method is UDP and there is no UDP listener,
# then we'll get ECONNREFUSED on the send). So what we
# want to do at this point is to fallback onto a different
while (scalar @fallbackMethods || $syslog_send) {
if ($failed && (time - $fail_time) > 60) {
# it's been a while... maybe things have been fixed
$transmit_ok = 0; # make it look like a fresh attempt
if ($connected && !connection_ok
()) {
# Something was OK, but has now broken. Remember coz we'll
# want to go back to what used to be OK.
$failed = $current_proto unless $failed;
&connect unless $connected;
$failed = undef if ($current_proto && $failed && $current_proto eq $failed);
if (&{$syslog_send}($buf)) {
# typically doesn't happen, since errors are rare from write().
# could not send, could not fallback onto a working
# connection method. Lose.
sub _syslog_send_console
{
chop($buf); # delete the NUL from the end
# The console print is a method which could block
# so we do it in a child process and always return success
if (waitpid($pid, 0) >= 0) {
# it's possible that the caller has other
# plans for SIGCHLD, so let's not interfere
if (open(CONS
, ">/dev/console")) {
my $ret = print CONS
$buf . "\r";
exit ($ret) if defined $pid;
sub _syslog_send_stream
{
# XXX: this only works if the OS stream implementation makes a write
# look like a putmsg() with simple header. For instance it works on
# Solaris 8 but not Solaris 7.
# To be correct, it should use a STREAMS API, but perl doesn't have one.
return syswrite(SYSLOG
, $buf, length($buf));
sub _syslog_send_socket
{
return syswrite(SYSLOG
, $buf, length($buf));
#return send(SYSLOG, $buf, 0);
return $name+0 if $name =~ /^\s*\d+\s*$/;
$name = "LOG_$name" unless $name =~ /^LOG_/;
$name = "Sys::Syslog::$name";
# Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
my $value = eval { no strict
'refs'; &$name };
defined $value ?
$value : -1;
@fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
if ($transmit_ok && $current_proto) {
# Retry what we were on, because it's worked in the past.
unshift(@fallbackMethods, $current_proto);
while ($proto = shift(@fallbackMethods)) {
my $fn = "connect_$proto";
$connected = &$fn(\
@errs) if defined &$fn;
my($old) = select(SYSLOG
); $| = 1; select($old);
croak
join "\n\t- ", "no connection to syslog available", @errs
my $tcp = getprotobyname('tcp');
push(@
{$errs}, "getprotobyname failed for tcp");
my $syslog = getservbyname('syslog','tcp');
$syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
push(@
{$errs}, "getservbyname failed for syslog/tcp and syslogng/tcp");
my $this = sockaddr_in
($syslog, INADDR_ANY
);
$that = inet_aton
($host);
push(@
{$errs}, "can't lookup $host");
$that = sockaddr_in
($syslog, $that);
if (!socket(SYSLOG
,AF_INET
,SOCK_STREAM
,$tcp)) {
push(@
{$errs}, "tcp socket: $!");
setsockopt(SYSLOG
, SOL_SOCKET
, SO_KEEPALIVE
, 1);
setsockopt(SYSLOG
, IPPROTO_TCP
, TCP_NODELAY
, 1);
if (!CORE
::connect(SYSLOG
,$that)) {
push(@
{$errs}, "tcp connect: $!");
$syslog_send = \
&_syslog_send_socket
;
my $udp = getprotobyname('udp');
push(@
{$errs}, "getprotobyname failed for udp");
my $syslog = getservbyname('syslog','udp');
push(@
{$errs}, "getservbyname failed for syslog/udp");
my $this = sockaddr_in
($syslog, INADDR_ANY
);
$that = inet_aton
($host);
push(@
{$errs}, "can't lookup $host");
$that = sockaddr_in
($syslog, $that);
if (!socket(SYSLOG
,AF_INET
,SOCK_DGRAM
,$udp)) {
push(@
{$errs}, "udp socket: $!");
if (!CORE
::connect(SYSLOG
,$that)) {
push(@
{$errs}, "udp connect: $!");
# We want to check that the UDP connect worked. However the only
# way to do that is to send a message and see if an ICMP is returned
push(@
{$errs}, "udp connect: nobody listening");
$syslog_send = \
&_syslog_send_socket
;
# might want syslog_path to be variable based on syslog.h (if only
$syslog_path = '/dev/conslog';
push(@
{$errs}, "stream $syslog_path is not writable");
if (!open(SYSLOG
, ">" . $syslog_path)) {
push(@
{$errs}, "stream can't open $syslog_path: $!");
$syslog_send = \
&_syslog_send_stream
;
if (length _PATH_LOG
()) {
$syslog_path = _PATH_LOG
();
push(@
{$errs}, "_PATH_LOG not available in syslog.h");
push(@
{$errs}, "$syslog_path is not a socket");
my $that = sockaddr_un
($syslog_path);
push(@
{$errs}, "can't locate $syslog_path");
if (!socket(SYSLOG
,AF_UNIX
,SOCK_STREAM
,0)) {
push(@
{$errs}, "unix stream socket: $!");
if (!CORE
::connect(SYSLOG
,$that)) {
if (!socket(SYSLOG
,AF_UNIX
,SOCK_DGRAM
,0)) {
push(@
{$errs}, "unix dgram socket: $!");
if (!CORE
::connect(SYSLOG
,$that)) {
push(@
{$errs}, "unix dgram connect: $!");
$syslog_send = \
&_syslog_send_socket
;
if (!-w
'/dev/console') {
push(@
{$errs}, "console is not writable");
$syslog_send = \
&_syslog_send_console
;
# to test if the connection is still good, we need to check if any
# errors are present on the connection. The errors will not be raised
# by a write. Instead, sockets are made readable and the next read
# would cause the error to be returned. Unfortunately the syslog
# 'protocol' never provides anything for us to read. But with
# judicious use of select(), we can see if it would be readable...
return 1 if (defined $current_proto && $current_proto eq 'console');
vec($rin, fileno(SYSLOG
), 1) = 1;
my $ret = select $rin, undef, $rin, 0;