package Sys::Syslog;
-require 5.000;
+require 5.006;
require Exporter;
-require DynaLoader;
use Carp;
-
-@ISA = qw(Exporter DynaLoader);
-@EXPORT = qw(openlog closelog setlogmask syslog);
-@EXPORT_OK = qw(setlogsock);
-$VERSION = '0.01';
-
-use Socket;
+use strict;
+
+our @ISA = qw(Exporter);
+our @EXPORT = qw(openlog closelog setlogmask syslog);
+our @EXPORT_OK = qw(setlogsock);
+our $VERSION = '0.08';
+
+# it would be nice to try stream/unix first, since that will be
+# most efficient. However streams are dodgy - see _syslog_send_stream
+my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
+if ($^O =~ /^(freebsd|linux)$/) {
+ @connectMethods = grep { $_ ne 'udp' } @connectMethods;
+}
+my @defaultMethods = @connectMethods;
+my $syslog_path = undef;
+my $transmit_ok = 0;
+my $current_proto = undef;
+my $failed = undef;
+my $fail_time = undef;
+our ($connected, @fallbackMethods, $syslog_send, $host);
+
+use Socket ':all';
use Sys::Hostname;
-# 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)
-# Modified to add UNIX domain sockets by Sean Robinson <robinson_s@sc.maricopa.edu>
-# with support from Tim Bunce <Tim.Bunce@ig.co.uk> and the perl5-porters mailing list
-# Modified to use an XS backend instead of syslog.ph by Tom Hughes <tom@compton.nu>
-
-# Todo: enable connect to try all three types before failing (auto setlogsock)?
-
=head1 NAME
Sys::Syslog, openlog, closelog, setlogmask, syslog - Perl interface to the UNIX syslog(3) calls
use Sys::Syslog qw(:DEFAULT setlogsock); # default set, plus setlogsock
setlogsock $sock_type;
- openlog $ident, $logopt, $facility;
+ openlog $ident, $logopt, $facility; # don't forget this
syslog $priority, $format, @args;
$oldmask = setlogmask $mask_priority;
closelog;
Syslog provides the functions:
-=over
+=over 4
=item openlog $ident, $logopt, $facility
-I<$ident> is prepended to every message.
-I<$logopt> contains zero or more of the words I<pid>, I<ndelay>, I<cons>, I<nowait>.
-I<$facility> specifies the part of the system
+Opens the syslog.
+I<$ident> is prepended to every message. I<$logopt> contains zero or
+more of the words I<pid>, I<ndelay>, I<nowait>. The cons option is
+ignored, since the failover mechanism will drop down to the console
+automatically if all other media fail. I<$facility> specifies the
+part of the system to report about, for example LOG_USER or LOG_LOCAL0:
+see your C<syslog(3)> documentation for the facilities available in
+your system. This function will croak if it can't connect to the syslog
+daemon.
+
+B<You should use openlog() before calling syslog().>
+
+=item syslog $priority, $message
=item syslog $priority, $format, @args
-If I<$priority> permits, logs I<($format, @args)>
-printed as by C<printf(3V)>, with the addition that I<%m>
-is replaced with C<"$!"> (the latest error message).
+If I<$priority> permits, logs I<$message> or I<sprintf($format, @args)>
+with the addition that I<%m> in $message or $format is replaced with
+C<"$!"> (the latest error message).
+
+If you didn't use openlog() before using syslog(), syslog will try to
+guess the I<$ident> by extracting the shortest prefix of I<$format>
+that ends in a ":".
+
+Note that 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.
=item setlogmask $mask_priority
Sets log mask I<$mask_priority> and returns the old mask.
-=item setlogsock $sock_type (added in 5.004_02)
+=item 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,
undef on failure.
-A value of 'unix' will connect to the UNIX domain socket returned by the
-C<_PATH_LOG> macro (if you system defines it) in F<syslog.h>. A value of
-'inet' will connect to an INET socket returned by getservbyname(). If
-C<_PATH_LOG> is unavailable or if getservbyname() fails, returns undef. Any
-other value croaks.
+A value of '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 '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.
-The default is for the INET socket to be used.
+Giving an invalid value for sock_type will croak.
=item closelog
=head1 EXAMPLES
openlog($program, 'cons,pid', 'user');
- syslog('info', 'this is another test');
+ syslog('info', '%s', 'this is another test');
syslog('mail|warning', 'this is a better test: %d', time);
closelog();
$! = 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');
+
=head1 SEE ALSO
L<syslog(3)>
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<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
E<lt>F<Tim.Bunce@ig.co.uk>E<gt> and the 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 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>.
+
=cut
sub AUTOLOAD {
# This AUTOLOAD is used to 'autoload' constants from the constant()
# XS function.
-
+
my $constname;
our $AUTOLOAD;
($constname = $AUTOLOAD) =~ s/.*:://;
- croak "& not defined" if $constname eq 'constant';
- my $val = constant($constname);
- if ($! != 0) {
- croak "Your vendor has not defined Sys::Syslog macro $constname";
+ croak "&Sys::Syslog::constant not defined" if $constname eq 'constant';
+ my ($error, $val) = constant($constname);
+ if ($error) {
+ croak $error;
}
+ no strict 'refs';
*$AUTOLOAD = sub { $val };
goto &$AUTOLOAD;
}
-bootstrap Sys::Syslog $VERSION;
+require XSLoader;
+XSLoader::load('Sys::Syslog', $VERSION);
-$maskpri = &LOG_UPTO(&LOG_DEBUG);
+our $maskpri = &LOG_UPTO(&LOG_DEBUG);
sub openlog {
- ($ident, $logopt, $facility) = @_; # package vars
- $lo_pid = $logopt =~ /\bpid\b/;
- $lo_ndelay = $logopt =~ /\bndelay\b/;
- $lo_cons = $logopt =~ /\bcons\b/;
- $lo_nowait = $logopt =~ /\bnowait\b/;
+ our ($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;
&connect;
}
sub closelog {
- $facility = $ident = '';
+ our $facility = our $ident = '';
&disconnect;
}
sub setlogmask {
- local($oldmask) = $maskpri;
+ my $oldmask = $maskpri;
$maskpri = shift;
$oldmask;
}
sub setlogsock {
- local($setsock) = shift;
+ my $setsock = shift;
+ $syslog_path = shift;
&disconnect if $connected;
- if (lc($setsock) eq 'unix') {
- if (length _PATH_LOG()) {
- $sock_type = 1;
- } else {
- return undef;
+ $transmit_ok = 0;
+ @fallbackMethods = ();
+ @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;
+ }
+ for my $try (@try) {
+ if (-w $try) {
+ $syslog_path = $try;
+ last;
+ }
+ }
+ carp "stream passed to setlogsock, but could not find any device"
+ unless defined $syslog_path;
}
- } elsif (lc($setsock) eq 'inet') {
- if (getservbyname('syslog','udp')) {
- undef($sock_type);
+ unless (-w $syslog_path) {
+ carp "stream passed to setlogsock, but $syslog_path is not writable";
+ return undef;
+ } else {
+ @connectMethods = ( 'stream' );
+ }
+ } elsif (lc($setsock) eq 'unix') {
+ if (length _PATH_LOG() && !defined $syslog_path) {
+ $syslog_path = _PATH_LOG();
+ @connectMethods = ( 'unix' );
} else {
- return undef;
+ carp 'unix passed to setlogsock, but path not available';
+ return undef;
}
+ } elsif (lc($setsock) eq 'tcp') {
+ if (getservbyname('syslog', 'tcp') || getservbyname('syslogng', 'tcp')) {
+ @connectMethods = ( 'tcp' );
+ } else {
+ carp "tcp passed to setlogsock, but tcp service unavailable";
+ return undef;
+ }
+ } elsif (lc($setsock) eq 'udp') {
+ if (getservbyname('syslog', 'udp')) {
+ @connectMethods = ( 'udp' );
+ } else {
+ carp "udp passed to setlogsock, but udp service unavailable";
+ return undef;
+ }
+ } elsif (lc($setsock) eq 'inet') {
+ @connectMethods = ( 'tcp', 'udp' );
+ } elsif (lc($setsock) eq 'console') {
+ @connectMethods = ( 'console' );
} else {
- croak "Invalid argument passed to setlogsock; must be 'unix' or 'inet'";
+ carp "Invalid argument passed to setlogsock; must be 'stream', 'unix', 'tcp', 'udp' or 'inet'";
}
return 1;
}
sub syslog {
- local($priority) = shift;
- local($mask) = shift;
- local($message, $whoami);
- local(@words, $num, $numpri, $numfac, $sum);
+ my $priority = shift;
+ my $mask = shift;
+ my ($message, $whoami);
+ my (@words, $num, $numpri, $numfac, $sum);
+ our $facility;
local($facility) = $facility; # may need to change temporarily.
- croak "syslog: expected both priority and mask" unless $mask && $priority;
+ croak "syslog: expecting argument \$priority" unless $priority;
+ croak "syslog: expecting argument \$format" unless $mask;
@words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
undef $numpri;
&connect unless $connected;
- $whoami = $ident;
+ $whoami = our $ident;
if (!$whoami && $mask =~ /^(\S.*?):\s?(.*)/) {
$whoami = $1;
($whoami = 'syslog');
}
- $whoami .= "[$$]" if $lo_pid;
+ $whoami .= "[$$]" if our $lo_pid;
+
+ if ($mask =~ /%m/) {
+ my $err = $!;
+ # escape percent signs if sprintf will be called
+ $err =~ s/%/%%/g if @_;
+ # replace %m with $err, if preceded by an even number of percent signs
+ $mask =~ s/(?<!%)((?:%%)*)%m/$1$err/g;
+ }
- $mask =~ s/%m/$!/g;
$mask .= "\n" unless $mask =~ /\n$/;
- $message = sprintf ($mask, @_);
+ $message = @_ ? sprintf($mask, @_) : $mask;
$sum = $numpri + $numfac;
- unless (send(SYSLOG,"<$sum>$whoami: $message\0",0)) {
- if ($lo_cons) {
- if ($pid = fork) {
- unless ($lo_nowait) {
- $died = waitpid($pid, 0);
- }
+ my $buf = "<$sum>$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
+ # connection method.
+ while (scalar @fallbackMethods || $syslog_send) {
+ if ($failed && (time - $fail_time) > 60) {
+ # it's been a while... maybe things have been fixed
+ @fallbackMethods = ();
+ disconnect();
+ $transmit_ok = 0; # make it look like a fresh attempt
+ &connect;
+ }
+ if ($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;
+ $fail_time = time;
+ disconnect();
+ }
+ &connect unless $connected;
+ $failed = undef if ($current_proto && $failed && $current_proto eq $failed);
+ if ($syslog_send) {
+ if (&{$syslog_send}($buf)) {
+ $transmit_ok++;
+ return 1;
}
- else {
- if (open(CONS,">/dev/console")) {
- print CONS "<$facility.$priority>$whoami: $message\r";
- close CONS;
- }
- exit if defined $pid; # if fork failed, we're parent
+ # typically doesn't happen, since errors are rare from write().
+ disconnect();
+ }
+ }
+ # could not send, could not fallback onto a working
+ # connection method. Lose.
+ return 0;
+}
+
+sub _syslog_send_console {
+ my ($buf) = @_;
+ 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
+ # to the caller.
+ if (my $pid = fork) {
+ our $lo_nowait;
+ if ($lo_nowait) {
+ return 1;
+ } else {
+ if (waitpid($pid, 0) >= 0) {
+ return ($? >> 8);
+ } else {
+ # it's possible that the caller has other
+ # plans for SIGCHLD, so let's not interfere
+ return 1;
}
}
+ } else {
+ if (open(CONS, ">/dev/console")) {
+ my $ret = print CONS $buf . "\r";
+ exit ($ret) if defined $pid;
+ close CONS;
+ }
+ exit if defined $pid;
}
}
+sub _syslog_send_stream {
+ my ($buf) = @_;
+ # 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 {
+ my ($buf) = @_;
+ return syswrite(SYSLOG, $buf, length($buf));
+ #return send(SYSLOG, $buf, 0);
+}
+
sub xlate {
- local($name) = @_;
+ my($name) = @_;
+ return $name+0 if $name =~ /^\s*\d+\s*$/;
$name = uc $name;
$name = "LOG_$name" unless $name =~ /^LOG_/;
$name = "Sys::Syslog::$name";
- eval { &$name } || -1;
+ # Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
+ my $value = eval { no strict 'refs'; &$name };
+ defined $value ? $value : -1;
}
sub connect {
+ @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
+ if ($transmit_ok && $current_proto) {
+ # Retry what we were on, because it's worked in the past.
+ unshift(@fallbackMethods, $current_proto);
+ }
+ $connected = 0;
+ my @errs = ();
+ my $proto = undef;
+ while ($proto = shift(@fallbackMethods)) {
+ no strict 'refs';
+ my $fn = "connect_$proto";
+ $connected = &$fn(\@errs) if defined &$fn;
+ last if ($connected);
+ }
+
+ $transmit_ok = 0;
+ if ($connected) {
+ $current_proto = $proto;
+ my($old) = select(SYSLOG); $| = 1; select($old);
+ } else {
+ @fallbackMethods = ();
+ foreach my $err (@errs) {
+ carp $err;
+ }
+ croak "no connection to syslog available";
+ }
+}
+
+sub connect_tcp {
+ my ($errs) = @_;
+ unless ($host) {
+ require Sys::Hostname;
+ my($host_uniq) = Sys::Hostname::hostname();
+ ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
+ }
+ my $tcp = getprotobyname('tcp');
+ if (!defined $tcp) {
+ push(@{$errs}, "getprotobyname failed for tcp");
+ return 0;
+ }
+ my $syslog = getservbyname('syslog','tcp');
+ $syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
+ if (!defined $syslog) {
+ push(@{$errs}, "getservbyname failed for tcp");
+ return 0;
+ }
+
+ my $this = sockaddr_in($syslog, INADDR_ANY);
+ my $that = sockaddr_in($syslog, inet_aton($host));
+ if (!$that) {
+ push(@{$errs}, "can't lookup $host");
+ return 0;
+ }
+ if (!socket(SYSLOG,AF_INET,SOCK_STREAM,$tcp)) {
+ push(@{$errs}, "tcp socket: $!");
+ return 0;
+ }
+ setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
+ setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
+ if (!CORE::connect(SYSLOG,$that)) {
+ push(@{$errs}, "tcp connect: $!");
+ return 0;
+ }
+ $syslog_send = \&_syslog_send_socket;
+ return 1;
+}
+
+sub connect_udp {
+ my ($errs) = @_;
unless ($host) {
require Sys::Hostname;
my($host_uniq) = Sys::Hostname::hostname();
($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
}
- unless ( $sock_type ) {
- 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: $!";
+ my $udp = getprotobyname('udp');
+ if (!defined $udp) {
+ push(@{$errs}, "getprotobyname failed for udp");
+ return 0;
+ }
+ my $syslog = getservbyname('syslog','udp');
+ if (!defined $syslog) {
+ push(@{$errs}, "getservbyname failed for udp");
+ return 0;
+ }
+ my $this = sockaddr_in($syslog, INADDR_ANY);
+ my $that = sockaddr_in($syslog, inet_aton($host));
+ if (!$that) {
+ push(@{$errs}, "can't lookup $host");
+ return 0;
+ }
+ if (!socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp)) {
+ push(@{$errs}, "udp socket: $!");
+ return 0;
+ }
+ if (!CORE::connect(SYSLOG,$that)) {
+ push(@{$errs}, "udp connect: $!");
+ return 0;
+ }
+ # We want to check that the UDP connect worked. However the only
+ # way to do that is to send a message and see if an ICMP is returned
+ _syslog_send_socket("");
+ if (!connection_ok()) {
+ push(@{$errs}, "udp connect: nobody listening");
+ return 0;
+ }
+ $syslog_send = \&_syslog_send_socket;
+ return 1;
+}
+
+sub connect_stream {
+ my ($errs) = @_;
+ # might want syslog_path to be variable based on syslog.h (if only
+ # it were in there!)
+ $syslog_path = '/dev/conslog';
+ if (!-w $syslog_path) {
+ push(@{$errs}, "stream $syslog_path is not writable");
+ return 0;
+ }
+ if (!open(SYSLOG, ">" . $syslog_path)) {
+ push(@{$errs}, "stream can't open $syslog_path: $!");
+ return 0;
+ }
+ $syslog_send = \&_syslog_send_stream;
+ return 1;
+}
+
+sub connect_unix {
+ my ($errs) = @_;
+ if (length _PATH_LOG()) {
+ $syslog_path = _PATH_LOG();
} else {
- my $syslog = _PATH_LOG();
- length($syslog) || croak "_PATH_LOG unavailable in syslog.h";
- my $that = sockaddr_un($syslog) || croak "Can't locate $syslog";
- socket(SYSLOG,AF_UNIX,SOCK_STREAM,0) || croak "socket: $!";
- if (!connect(SYSLOG,$that)) {
- socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0) || croak "socket: $!";
- connect(SYSLOG,$that) || croak "connect: $! (SOCK_DGRAM after trying SOCK_STREAM)";
- }
+ push(@{$errs}, "_PATH_LOG not available in syslog.h");
+ return 0;
+ }
+ my $that = sockaddr_un($syslog_path);
+ if (!$that) {
+ push(@{$errs}, "can't locate $syslog_path");
+ return 0;
}
- local($old) = select(SYSLOG); $| = 1; select($old);
- $connected = 1;
+ if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
+ push(@{$errs}, "unix stream socket: $!");
+ return 0;
+ }
+ if (!CORE::connect(SYSLOG,$that)) {
+ if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
+ push(@{$errs}, "unix dgram socket: $!");
+ return 0;
+ }
+ if (!CORE::connect(SYSLOG,$that)) {
+ push(@{$errs}, "unix dgram connect: $!");
+ return 0;
+ }
+ }
+ $syslog_send = \&_syslog_send_socket;
+ return 1;
+}
+
+sub connect_console {
+ my ($errs) = @_;
+ if (!-w '/dev/console') {
+ push(@{$errs}, "console is not writable");
+ return 0;
+ }
+ $syslog_send = \&_syslog_send_console;
+ return 1;
+}
+
+# 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...
+sub connection_ok {
+ return 1 if (defined $current_proto && $current_proto eq 'console');
+ my $rin = '';
+ vec($rin, fileno(SYSLOG), 1) = 1;
+ my $ret = select $rin, undef, $rin, 0;
+ return ($ret ? 0 : 1);
}
sub disconnect {
close SYSLOG;
$connected = 0;
+ $syslog_send = undef;
}
1;
https://perl5.git.perl.org / perl5.git / blobdiff