7 @ISA = qw(Exporter DynaLoader);
8 @EXPORT = qw(openlog closelog setlogmask syslog);
9 @EXPORT_OK = qw(setlogsock);
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 = ( 'stream', 'unix', 'tcp', 'udp' );
15 my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
16 if ($^O =~ /^(freebsd|linux)$/) {
17 @connectMethods = grep { $_ ne 'udp' } @connectMethods;
19 my @defaultMethods = @connectMethods;
20 my $syslog_path = undef;
22 my $current_proto = undef;
24 my $fail_time = undef;
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, $facility
56 I<$ident> is prepended to every message. I<$logopt> contains zero or
57 more of the words I<pid>, I<ndelay>, I<nowait>. The cons option is
58 ignored, since the failover mechanism will drop down to the console
59 automatically if all other media fail. I<$facility> specifies the
60 part of the system to report about, for example LOG_USER or LOG_LOCAL0:
61 see your C<syslog(3)> documentation for the facilities available in
64 B<You should use openlog() before calling syslog().>
66 =item syslog $priority, $format, @args
68 If I<$priority> permits, logs I<($format, @args)>
69 printed as by C<printf(3V)>, with the addition that I<%m>
70 is replaced with C<"$!"> (the latest error message).
72 If you didn't use openlog() before using syslog(), syslog will try to
73 guess the I<$ident> by extracting the shortest prefix of I<$format>
76 =item setlogmask $mask_priority
78 Sets log mask I<$mask_priority> and returns the old mask.
80 =item setlogsock $sock_type [$stream_location] (added in 5.004_02)
82 Sets the socket type to be used for the next call to
83 C<openlog()> or C<syslog()> and returns TRUE on success,
86 A value of 'unix' will connect to the UNIX domain socket (in some
87 systems a character special device) returned by the C<_PATH_LOG> macro
88 (if your system defines it), or F</dev/log> or F</dev/conslog>,
89 whatever is writable. A value of 'stream' will connect to the stream
90 indicated by the pathname provided as the optional second parameter.
91 (For example Solaris and IRIX require 'stream' instead of 'unix'.)
92 A value of 'inet' will connect to an INET socket (either tcp or udp,
93 tried in that order) returned by getservbyname(). 'tcp' and 'udp' can
94 also be given as values. The value 'console' will send messages
95 directly to the console, as for the 'cons' option in the logopts in
98 A reference to an array can also be passed as the first parameter.
99 When this calling method is used, the array should contain a list of
100 sock_types which are attempted in order.
102 The default is to try tcp, udp, unix, stream, console.
104 Giving an invalid value for sock_type will croak.
112 Note that C<openlog> now takes three arguments, just like C<openlog(3)>.
116 openlog($program, 'cons,pid', 'user');
117 syslog('info', 'this is another test');
118 syslog('mail|warning', 'this is a better test: %d', time);
121 syslog('debug', 'this is the last test');
124 openlog("$program $$", 'ndelay', 'user');
125 syslog('notice', 'fooprogram: this is really done');
129 syslog('info', 'problem was %m'); # %m == $! in syslog(3)
137 Tom Christiansen E<lt>F<tchrist@perl.com>E<gt> and Larry Wall
138 E<lt>F<larry@wall.org>E<gt>.
140 UNIX domain sockets added by Sean Robinson
141 E<lt>F<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
142 E<lt>F<Tim.Bunce@ig.co.uk>E<gt> and the perl5-porters mailing list.
144 Dependency on F<syslog.ph> replaced with XS code by Tom Hughes
145 E<lt>F<tom@compton.nu>E<gt>.
147 Code for constant()s regenerated by Nicholas Clark E<lt>F<nick@ccl4.org>E<gt>.
149 Failover to different communication modes by Nick Williams
150 E<lt>F<Nick.Williams@morganstanley.com>E<gt>.
155 # This AUTOLOAD is used to 'autoload' constants from the constant()
160 ($constname = $AUTOLOAD) =~ s/.*:://;
161 croak "&Sys::Syslog::constant not defined" if $constname eq 'constant';
162 my ($error, $val) = constant($constname);
166 *$AUTOLOAD = sub { $val };
170 bootstrap Sys::Syslog $VERSION;
172 $maskpri = &LOG_UPTO(&LOG_DEBUG);
175 ($ident, $logopt, $facility) = @_; # package vars
176 $lo_pid = $logopt =~ /\bpid\b/;
177 $lo_ndelay = $logopt =~ /\bndelay\b/;
178 $lo_nowait = $logopt =~ /\bnowait\b/;
179 return 1 unless $lo_ndelay;
184 $facility = $ident = '';
189 local($oldmask) = $maskpri;
195 local($setsock) = shift;
196 $syslog_path = shift;
197 &disconnect if $connected;
199 @fallbackMethods = ();
200 @connectMethods = @defaultMethods;
201 if (ref $setsock eq 'ARRAY') {
202 @connectMethods = @$setsock;
203 } elsif (lc($setsock) eq 'stream') {
204 unless (defined $syslog_path) {
205 my @try = qw(/dev/log /dev/conslog);
206 if (length &_PATH_LOG) { # Undefined _PATH_LOG is "".
207 unshift @try, &_PATH_LOG;
215 carp "stream passed to setlogsock, but could not find any device"
216 unless defined $syslog_path;
218 unless (-w $syslog_path) {
219 carp "stream passed to setlogsock, but $syslog_path is not writable";
222 @connectMethods = ( 'stream' );
224 } elsif (lc($setsock) eq 'unix') {
225 if (length _PATH_LOG() && !defined $syslog_path) {
226 $syslog_path = _PATH_LOG();
227 @connectMethods = ( 'unix' );
229 carp 'unix passed to setlogsock, but path not available';
232 } elsif (lc($setsock) eq 'tcp') {
233 if (getservbyname('syslog', 'tcp') || getservbyname('syslogng', 'tcp')) {
234 @connectMethods = ( 'tcp' );
236 carp "tcp passed to setlogsock, but tcp service unavailable";
239 } elsif (lc($setsock) eq 'udp') {
240 if (getservbyname('syslog', 'udp')) {
241 @connectMethods = ( 'udp' );
243 carp "udp passed to setlogsock, but udp service unavailable";
246 } elsif (lc($setsock) eq 'inet') {
247 @connectMethods = ( 'tcp', 'udp' );
248 } elsif (lc($setsock) eq 'console') {
249 @connectMethods = ( 'console' );
251 carp "Invalid argument passed to setlogsock; must be 'stream', 'unix', 'tcp', 'udp' or 'inet'";
257 local($priority) = shift;
258 local($mask) = shift;
259 local($message, $whoami);
260 local(@words, $num, $numpri, $numfac, $sum);
261 local($facility) = $facility; # may need to change temporarily.
263 croak "syslog: expecting argument \$priority" unless $priority;
264 croak "syslog: expecting argument \$format" unless $mask;
266 @words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
270 $num = &xlate($_); # Translate word to number.
271 if (/^kern$/ || $num < 0) {
272 croak "syslog: invalid level/facility: $_";
274 elsif ($num <= &LOG_PRIMASK) {
275 croak "syslog: too many levels given: $_" if defined($numpri);
277 return 0 unless &LOG_MASK($numpri) & $maskpri;
280 croak "syslog: too many facilities given: $_" if defined($numfac);
286 croak "syslog: level must be given" unless defined($numpri);
288 if (!defined($numfac)) { # Facility not specified in this call.
289 $facility = 'user' unless $facility;
290 $numfac = &xlate($facility);
293 &connect unless $connected;
297 if (!$whoami && $mask =~ /^(\S.*?):\s?(.*)/) {
303 ($whoami = getlogin) ||
304 ($whoami = getpwuid($<)) ||
305 ($whoami = 'syslog');
308 $whoami .= "[$$]" if $lo_pid;
311 $mask .= "\n" unless $mask =~ /\n$/;
312 $message = sprintf ($mask, @_);
314 $sum = $numpri + $numfac;
315 my $buf = "<$sum>$whoami: $message\0";
317 # it's possible that we'll get an error from sending
318 # (e.g. if method is UDP and there is no UDP listener,
319 # then we'll get ECONNREFUSED on the send). So what we
320 # want to do at this point is to fallback onto a different
322 while (scalar @fallbackMethods || $syslog_send) {
323 if ($failed && (time - $fail_time) > 60) {
324 # it's been a while... maybe things have been fixed
325 @fallbackMethods = ();
327 $transmit_ok = 0; # make it look like a fresh attempt
330 if ($connected && !connection_ok()) {
331 # Something was OK, but has now broken. Remember coz we'll
332 # want to go back to what used to be OK.
333 $failed = $current_proto unless $failed;
337 &connect unless $connected;
338 $failed = undef if ($current_proto && $failed && $current_proto eq $failed);
340 if (&{$syslog_send}($buf)) {
344 # typically doesn't happen, since errors are rare from write().
348 # could not send, could not fallback onto a working
349 # connection method. Lose.
353 sub _syslog_send_console {
355 chop($buf); # delete the NUL from the end
356 # The console print is a method which could block
357 # so we do it in a child process and always return success
359 if (my $pid = fork) {
363 if (waitpid($pid, 0) >= 0) {
366 # it's possible that the caller has other
367 # plans for SIGCHLD, so let's not interfere
372 if (open(CONS, ">/dev/console")) {
373 my $ret = print CONS $buf . "\r";
374 exit ($ret) if defined $pid;
377 exit if defined $pid;
381 sub _syslog_send_stream {
383 # XXX: this only works if the OS stream implementation makes a write
384 # look like a putmsg() with simple header. For instance it works on
385 # Solaris 8 but not Solaris 7.
386 # To be correct, it should use a STREAMS API, but perl doesn't have one.
387 return syswrite(SYSLOG, $buf, length($buf));
389 sub _syslog_send_socket {
391 return syswrite(SYSLOG, $buf, length($buf));
392 #return send(SYSLOG, $buf, 0);
397 return $name+0 if $name =~ /^\s*\d+\s*$/;
399 $name = "LOG_$name" unless $name =~ /^LOG_/;
400 $name = "Sys::Syslog::$name";
401 # Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
402 my $value = eval { &$name };
403 defined $value ? $value : -1;
407 @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
408 if ($transmit_ok && $current_proto) {
409 # Retry what we were on, because it's worked in the past.
410 unshift(@fallbackMethods, $current_proto);
415 while ($proto = shift(@fallbackMethods)) {
416 my $fn = "connect_$proto";
417 $connected = &$fn(\@errs) unless (!defined &$fn);
418 last if ($connected);
423 $current_proto = $proto;
424 local($old) = select(SYSLOG); $| = 1; select($old);
426 @fallbackMethods = ();
427 foreach my $err (@errs) {
430 croak "no connection to syslog available";
437 require Sys::Hostname;
438 my($host_uniq) = Sys::Hostname::hostname();
439 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
441 my $tcp = getprotobyname('tcp');
443 push(@{$errs}, "getprotobyname failed for tcp");
446 my $syslog = getservbyname('syslog','tcp');
447 $syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
448 if (!defined $syslog) {
449 push(@{$errs}, "getservbyname failed for tcp");
453 my $this = sockaddr_in($syslog, INADDR_ANY);
454 my $that = sockaddr_in($syslog, inet_aton($host));
456 push(@{$errs}, "can't lookup $host");
459 if (!socket(SYSLOG,AF_INET,SOCK_STREAM,$tcp)) {
460 push(@{$errs}, "tcp socket: $!");
463 setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
464 setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
465 if (!CORE::connect(SYSLOG,$that)) {
466 push(@{$errs}, "tcp connect: $!");
469 $syslog_send = \&_syslog_send_socket;
476 require Sys::Hostname;
477 my($host_uniq) = Sys::Hostname::hostname();
478 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
480 my $udp = getprotobyname('udp');
482 push(@{$errs}, "getprotobyname failed for udp");
485 my $syslog = getservbyname('syslog','udp');
486 if (!defined $syslog) {
487 push(@{$errs}, "getservbyname failed for udp");
490 my $this = sockaddr_in($syslog, INADDR_ANY);
491 my $that = sockaddr_in($syslog, inet_aton($host));
493 push(@{$errs}, "can't lookup $host");
496 if (!socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp)) {
497 push(@{$errs}, "udp socket: $!");
500 if (!CORE::connect(SYSLOG,$that)) {
501 push(@{$errs}, "udp connect: $!");
504 # We want to check that the UDP connect worked. However the only
505 # way to do that is to send a message and see if an ICMP is returned
506 _syslog_send_socket("");
507 if (!connection_ok()) {
508 push(@{$errs}, "udp connect: nobody listening");
511 $syslog_send = \&_syslog_send_socket;
517 # might want syslog_path to be variable based on syslog.h (if only
519 $syslog_path = '/dev/conslog';
520 if (!-w $syslog_path) {
521 push(@{$errs}, "stream $syslog_path is not writable");
524 if (!open(SYSLOG, ">" . $syslog_path)) {
525 push(@{$errs}, "stream can't open $syslog_path: $!");
528 $syslog_send = \&_syslog_send_stream;
534 if (length _PATH_LOG()) {
535 $syslog_path = _PATH_LOG();
537 push(@{$errs}, "_PATH_LOG not available in syslog.h");
540 my $that = sockaddr_un($syslog_path);
542 push(@{$errs}, "can't locate $syslog_path");
545 if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
546 push(@{$errs}, "unix stream socket: $!");
549 if (!CORE::connect(SYSLOG,$that)) {
550 if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
551 push(@{$errs}, "unix dgram socket: $!");
554 if (!CORE::connect(SYSLOG,$that)) {
555 push(@{$errs}, "unix dgram connect: $!");
559 $syslog_send = \&_syslog_send_socket;
563 sub connect_console {
565 if (!-w '/dev/console') {
566 push(@{$errs}, "console is not writable");
569 $syslog_send = \&_syslog_send_console;
573 # to test if the connection is still good, we need to check if any
574 # errors are present on the connection. The errors will not be raised
575 # by a write. Instead, sockets are made readable and the next read
576 # would cause the error to be returned. Unfortunately the syslog
577 # 'protocol' never provides anything for us to read. But with
578 # judicious use of select(), we can see if it would be readable...
580 return 1 if (defined $current_proto && $current_proto eq 'console');
582 vec($rin, fileno(SYSLOG), 1) = 1;
583 my $ret = select $rin, undef, $rin, 0;
584 return ($ret ? 0 : 1);
590 $syslog_send = undef;