7 our @ISA = qw(Exporter);
8 our @EXPORT = qw(openlog closelog setlogmask syslog);
9 our @EXPORT_OK = qw(setlogsock);
10 our $VERSION = '0.08';
12 # it would be nice to try stream/unix first, since that will be
13 # most efficient. However streams are dodgy - see _syslog_send_stream
14 my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
15 if ($^O =~ /^(freebsd|linux)$/) {
16 @connectMethods = grep { $_ ne 'udp' } @connectMethods;
18 my @defaultMethods = @connectMethods;
19 my $syslog_path = undef;
21 my $current_proto = undef;
23 my $fail_time = undef;
24 our ($connected, @fallbackMethods, $syslog_send, $host);
31 Sys::Syslog, openlog, closelog, setlogmask, syslog - Perl interface to the UNIX syslog(3) calls
35 use Sys::Syslog; # all except setlogsock, or:
36 use Sys::Syslog qw(:DEFAULT setlogsock); # default set, plus setlogsock
38 setlogsock $sock_type;
39 openlog $ident, $logopt, $facility; # don't forget this
40 syslog $priority, $format, @args;
41 $oldmask = setlogmask $mask_priority;
46 Sys::Syslog is an interface to the UNIX C<syslog(3)> program.
47 Call C<syslog()> with a string priority and a list of C<printf()> args
48 just like C<syslog(3)>.
50 Syslog provides the functions:
54 =item openlog $ident, $logopt, $facility
57 I<$ident> is prepended to every message. I<$logopt> contains zero or
58 more of the words I<pid>, I<ndelay>, I<nowait>. The cons option is
59 ignored, since the failover mechanism will drop down to the console
60 automatically if all other media fail. I<$facility> specifies the
61 part of the system to report about, for example LOG_USER or LOG_LOCAL0:
62 see your C<syslog(3)> documentation for the facilities available in
63 your system. This function will croak if it can't connect to the syslog
66 B<You should use openlog() before calling syslog().>
68 =item syslog $priority, $message
70 =item syslog $priority, $format, @args
72 If I<$priority> permits, logs I<$message> or I<sprintf($format, @args)>
73 with the addition that I<%m> in $message or $format is replaced with
74 C<"$!"> (the latest error message).
76 If you didn't use openlog() before using syslog(), syslog will try to
77 guess the I<$ident> by extracting the shortest prefix of I<$format>
80 Note that Sys::Syslog version v0.07 and older passed the $message as
81 the formatting string to sprintf() even when no formatting arguments
82 were provided. If the code calling syslog() might execute with older
83 versions of this module, make sure to call the function as
84 syslog($priority, "%s", $message) instead of syslog($priority,
85 $message). This protects against hostile formatting sequences that
86 might show up if $message contains tainted data.
88 =item setlogmask $mask_priority
90 Sets log mask I<$mask_priority> and returns the old mask.
92 =item setlogsock $sock_type [$stream_location] (added in 5.004_02)
94 Sets the socket type to be used for the next call to
95 C<openlog()> or C<syslog()> and returns TRUE on success,
98 A value of 'unix' will connect to the UNIX domain socket (in some
99 systems a character special device) returned by the C<_PATH_LOG> macro
100 (if your system defines it), or F</dev/log> or F</dev/conslog>,
101 whatever is writable. A value of 'stream' will connect to the stream
102 indicated by the pathname provided as the optional second parameter.
103 (For example Solaris and IRIX require 'stream' instead of 'unix'.)
104 A value of 'inet' will connect to an INET socket (either tcp or udp,
105 tried in that order) returned by getservbyname(). 'tcp' and 'udp' can
106 also be given as values. The value 'console' will send messages
107 directly to the console, as for the 'cons' option in the logopts in
110 A reference to an array can also be passed as the first parameter.
111 When this calling method is used, the array should contain a list of
112 sock_types which are attempted in order.
114 The default is to try tcp, udp, unix, stream, console.
116 Giving an invalid value for sock_type will croak.
124 Note that C<openlog> now takes three arguments, just like C<openlog(3)>.
128 openlog($program, 'cons,pid', 'user');
129 syslog('info', '%s', 'this is another test');
130 syslog('mail|warning', 'this is a better test: %d', time);
133 syslog('debug', 'this is the last test');
136 openlog("$program $$", 'ndelay', 'user');
137 syslog('notice', 'fooprogram: this is really done');
141 syslog('info', 'problem was %m'); # %m == $! in syslog(3)
143 # Log to UDP port on $remotehost instead of logging locally
145 $Sys::Syslog::host = $remotehost;
146 openlog($program, 'ndelay', 'user');
147 syslog('info', 'something happened over here');
155 Tom Christiansen E<lt>F<tchrist@perl.com>E<gt> and Larry Wall
156 E<lt>F<larry@wall.org>E<gt>.
158 UNIX domain sockets added by Sean Robinson
159 E<lt>F<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
160 E<lt>F<Tim.Bunce@ig.co.uk>E<gt> and the perl5-porters mailing list.
162 Dependency on F<syslog.ph> replaced with XS code by Tom Hughes
163 E<lt>F<tom@compton.nu>E<gt>.
165 Code for constant()s regenerated by Nicholas Clark E<lt>F<nick@ccl4.org>E<gt>.
167 Failover to different communication modes by Nick Williams
168 E<lt>F<Nick.Williams@morganstanley.com>E<gt>.
173 # This AUTOLOAD is used to 'autoload' constants from the constant()
178 ($constname = $AUTOLOAD) =~ s/.*:://;
179 croak "&Sys::Syslog::constant not defined" if $constname eq 'constant';
180 my ($error, $val) = constant($constname);
185 *$AUTOLOAD = sub { $val };
190 XSLoader::load('Sys::Syslog', $VERSION);
192 our $maskpri = &LOG_UPTO(&LOG_DEBUG);
195 our ($ident, $logopt, $facility) = @_; # package vars
196 our $lo_pid = $logopt =~ /\bpid\b/;
197 our $lo_ndelay = $logopt =~ /\bndelay\b/;
198 our $lo_nowait = $logopt =~ /\bnowait\b/;
199 return 1 unless $lo_ndelay;
204 our $facility = our $ident = '';
209 my $oldmask = $maskpri;
216 $syslog_path = shift;
217 &disconnect if $connected;
219 @fallbackMethods = ();
220 @connectMethods = @defaultMethods;
221 if (ref $setsock eq 'ARRAY') {
222 @connectMethods = @$setsock;
223 } elsif (lc($setsock) eq 'stream') {
224 unless (defined $syslog_path) {
225 my @try = qw(/dev/log /dev/conslog);
226 if (length &_PATH_LOG) { # Undefined _PATH_LOG is "".
227 unshift @try, &_PATH_LOG;
235 carp "stream passed to setlogsock, but could not find any device"
236 unless defined $syslog_path;
238 unless (-w $syslog_path) {
239 carp "stream passed to setlogsock, but $syslog_path is not writable";
242 @connectMethods = ( 'stream' );
244 } elsif (lc($setsock) eq 'unix') {
245 if (length _PATH_LOG() && !defined $syslog_path) {
246 $syslog_path = _PATH_LOG();
247 @connectMethods = ( 'unix' );
249 carp 'unix passed to setlogsock, but path not available';
252 } elsif (lc($setsock) eq 'tcp') {
253 if (getservbyname('syslog', 'tcp') || getservbyname('syslogng', 'tcp')) {
254 @connectMethods = ( 'tcp' );
256 carp "tcp passed to setlogsock, but tcp service unavailable";
259 } elsif (lc($setsock) eq 'udp') {
260 if (getservbyname('syslog', 'udp')) {
261 @connectMethods = ( 'udp' );
263 carp "udp passed to setlogsock, but udp service unavailable";
266 } elsif (lc($setsock) eq 'inet') {
267 @connectMethods = ( 'tcp', 'udp' );
268 } elsif (lc($setsock) eq 'console') {
269 @connectMethods = ( 'console' );
271 carp "Invalid argument passed to setlogsock; must be 'stream', 'unix', 'tcp', 'udp' or 'inet'";
277 my $priority = shift;
279 my ($message, $whoami);
280 my (@words, $num, $numpri, $numfac, $sum);
282 local($facility) = $facility; # may need to change temporarily.
284 croak "syslog: expecting argument \$priority" unless $priority;
285 croak "syslog: expecting argument \$format" unless $mask;
287 @words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
291 $num = &xlate($_); # Translate word to number.
292 if (/^kern$/ || $num < 0) {
293 croak "syslog: invalid level/facility: $_";
295 elsif ($num <= &LOG_PRIMASK) {
296 croak "syslog: too many levels given: $_" if defined($numpri);
298 return 0 unless &LOG_MASK($numpri) & $maskpri;
301 croak "syslog: too many facilities given: $_" if defined($numfac);
307 croak "syslog: level must be given" unless defined($numpri);
309 if (!defined($numfac)) { # Facility not specified in this call.
310 $facility = 'user' unless $facility;
311 $numfac = &xlate($facility);
314 &connect unless $connected;
316 $whoami = our $ident;
318 if (!$whoami && $mask =~ /^(\S.*?):\s?(.*)/) {
324 ($whoami = getlogin) ||
325 ($whoami = getpwuid($<)) ||
326 ($whoami = 'syslog');
329 $whoami .= "[$$]" if our $lo_pid;
333 # escape percent signs if sprintf will be called
334 $err =~ s/%/%%/g if @_;
335 # replace %m with $err, if preceded by an even number of percent signs
336 $mask =~ s/(?<!%)((?:%%)*)%m/$1$err/g;
339 $mask .= "\n" unless $mask =~ /\n$/;
340 $message = @_ ? sprintf($mask, @_) : $mask;
342 $sum = $numpri + $numfac;
343 my $buf = "<$sum>$whoami: $message\0";
345 # it's possible that we'll get an error from sending
346 # (e.g. if method is UDP and there is no UDP listener,
347 # then we'll get ECONNREFUSED on the send). So what we
348 # want to do at this point is to fallback onto a different
350 while (scalar @fallbackMethods || $syslog_send) {
351 if ($failed && (time - $fail_time) > 60) {
352 # it's been a while... maybe things have been fixed
353 @fallbackMethods = ();
355 $transmit_ok = 0; # make it look like a fresh attempt
358 if ($connected && !connection_ok()) {
359 # Something was OK, but has now broken. Remember coz we'll
360 # want to go back to what used to be OK.
361 $failed = $current_proto unless $failed;
365 &connect unless $connected;
366 $failed = undef if ($current_proto && $failed && $current_proto eq $failed);
368 if (&{$syslog_send}($buf)) {
372 # typically doesn't happen, since errors are rare from write().
376 # could not send, could not fallback onto a working
377 # connection method. Lose.
381 sub _syslog_send_console {
383 chop($buf); # delete the NUL from the end
384 # The console print is a method which could block
385 # so we do it in a child process and always return success
387 if (my $pid = fork) {
392 if (waitpid($pid, 0) >= 0) {
395 # it's possible that the caller has other
396 # plans for SIGCHLD, so let's not interfere
401 if (open(CONS, ">/dev/console")) {
402 my $ret = print CONS $buf . "\r";
403 exit ($ret) if defined $pid;
406 exit if defined $pid;
410 sub _syslog_send_stream {
412 # XXX: this only works if the OS stream implementation makes a write
413 # look like a putmsg() with simple header. For instance it works on
414 # Solaris 8 but not Solaris 7.
415 # To be correct, it should use a STREAMS API, but perl doesn't have one.
416 return syswrite(SYSLOG, $buf, length($buf));
418 sub _syslog_send_socket {
420 return syswrite(SYSLOG, $buf, length($buf));
421 #return send(SYSLOG, $buf, 0);
426 return $name+0 if $name =~ /^\s*\d+\s*$/;
428 $name = "LOG_$name" unless $name =~ /^LOG_/;
429 $name = "Sys::Syslog::$name";
430 # Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
431 my $value = eval { no strict 'refs'; &$name };
432 defined $value ? $value : -1;
436 @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
437 if ($transmit_ok && $current_proto) {
438 # Retry what we were on, because it's worked in the past.
439 unshift(@fallbackMethods, $current_proto);
444 while ($proto = shift(@fallbackMethods)) {
446 my $fn = "connect_$proto";
447 $connected = &$fn(\@errs) if defined &$fn;
448 last if ($connected);
453 $current_proto = $proto;
454 my($old) = select(SYSLOG); $| = 1; select($old);
456 @fallbackMethods = ();
457 foreach my $err (@errs) {
460 croak "no connection to syslog available";
467 require Sys::Hostname;
468 my($host_uniq) = Sys::Hostname::hostname();
469 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
471 my $tcp = getprotobyname('tcp');
473 push(@{$errs}, "getprotobyname failed for tcp");
476 my $syslog = getservbyname('syslog','tcp');
477 $syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
478 if (!defined $syslog) {
479 push(@{$errs}, "getservbyname failed for tcp");
483 my $this = sockaddr_in($syslog, INADDR_ANY);
484 my $that = sockaddr_in($syslog, inet_aton($host));
486 push(@{$errs}, "can't lookup $host");
489 if (!socket(SYSLOG,AF_INET,SOCK_STREAM,$tcp)) {
490 push(@{$errs}, "tcp socket: $!");
493 setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
494 setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
495 if (!CORE::connect(SYSLOG,$that)) {
496 push(@{$errs}, "tcp connect: $!");
499 $syslog_send = \&_syslog_send_socket;
506 require Sys::Hostname;
507 my($host_uniq) = Sys::Hostname::hostname();
508 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
510 my $udp = getprotobyname('udp');
512 push(@{$errs}, "getprotobyname failed for udp");
515 my $syslog = getservbyname('syslog','udp');
516 if (!defined $syslog) {
517 push(@{$errs}, "getservbyname failed for udp");
520 my $this = sockaddr_in($syslog, INADDR_ANY);
521 my $that = sockaddr_in($syslog, inet_aton($host));
523 push(@{$errs}, "can't lookup $host");
526 if (!socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp)) {
527 push(@{$errs}, "udp socket: $!");
530 if (!CORE::connect(SYSLOG,$that)) {
531 push(@{$errs}, "udp connect: $!");
534 # We want to check that the UDP connect worked. However the only
535 # way to do that is to send a message and see if an ICMP is returned
536 _syslog_send_socket("");
537 if (!connection_ok()) {
538 push(@{$errs}, "udp connect: nobody listening");
541 $syslog_send = \&_syslog_send_socket;
547 # might want syslog_path to be variable based on syslog.h (if only
549 $syslog_path = '/dev/conslog';
550 if (!-w $syslog_path) {
551 push(@{$errs}, "stream $syslog_path is not writable");
554 if (!open(SYSLOG, ">" . $syslog_path)) {
555 push(@{$errs}, "stream can't open $syslog_path: $!");
558 $syslog_send = \&_syslog_send_stream;
564 if (length _PATH_LOG()) {
565 $syslog_path = _PATH_LOG();
567 push(@{$errs}, "_PATH_LOG not available in syslog.h");
570 my $that = sockaddr_un($syslog_path);
572 push(@{$errs}, "can't locate $syslog_path");
575 if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
576 push(@{$errs}, "unix stream socket: $!");
579 if (!CORE::connect(SYSLOG,$that)) {
580 if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
581 push(@{$errs}, "unix dgram socket: $!");
584 if (!CORE::connect(SYSLOG,$that)) {
585 push(@{$errs}, "unix dgram connect: $!");
589 $syslog_send = \&_syslog_send_socket;
593 sub connect_console {
595 if (!-w '/dev/console') {
596 push(@{$errs}, "console is not writable");
599 $syslog_send = \&_syslog_send_console;
603 # to test if the connection is still good, we need to check if any
604 # errors are present on the connection. The errors will not be raised
605 # by a write. Instead, sockets are made readable and the next read
606 # would cause the error to be returned. Unfortunately the syslog
607 # 'protocol' never provides anything for us to read. But with
608 # judicious use of select(), we can see if it would be readable...
610 return 1 if (defined $current_proto && $current_proto eq 'console');
612 vec($rin, fileno(SYSLOG), 1) = 1;
613 my $ret = select $rin, undef, $rin, 0;
614 return ($ret ? 0 : 1);
620 $syslog_send = undef;