7 our @ISA = qw(Exporter);
8 our @EXPORT = qw(openlog closelog setlogmask syslog);
9 our @EXPORT_OK = qw(setlogsock);
10 our $VERSION = '0.07';
12 # it would be nice to try stream/unix first, since that will be
13 # most efficient. However streams are dodgy - see _syslog_send_stream
14 my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
15 if ($^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, $format, @args
70 If I<$priority> permits, logs I<($format, @args)>
71 printed as by C<printf(3V)>, with the addition that I<%m>
72 is replaced with C<"$!"> (the latest error message).
74 If you didn't use openlog() before using syslog(), syslog will try to
75 guess the I<$ident> by extracting the shortest prefix of I<$format>
78 =item setlogmask $mask_priority
80 Sets log mask I<$mask_priority> and returns the old mask.
82 =item setlogsock $sock_type [$stream_location] (added in 5.004_02)
84 Sets the socket type to be used for the next call to
85 C<openlog()> or C<syslog()> and returns TRUE on success,
88 A value of 'unix' will connect to the UNIX domain socket (in some
89 systems a character special device) returned by the C<_PATH_LOG> macro
90 (if your system defines it), or F</dev/log> or F</dev/conslog>,
91 whatever is writable. A value of 'stream' will connect to the stream
92 indicated by the pathname provided as the optional second parameter.
93 (For example Solaris and IRIX require 'stream' instead of 'unix'.)
94 A value of 'inet' will connect to an INET socket (either tcp or udp,
95 tried in that order) returned by getservbyname(). 'tcp' and 'udp' can
96 also be given as values. The value 'console' will send messages
97 directly to the console, as for the 'cons' option in the logopts in
100 A reference to an array can also be passed as the first parameter.
101 When this calling method is used, the array should contain a list of
102 sock_types which are attempted in order.
104 The default is to try tcp, udp, unix, stream, console.
106 Giving an invalid value for sock_type will croak.
114 Note that C<openlog> now takes three arguments, just like C<openlog(3)>.
118 openlog($program, 'cons,pid', 'user');
119 syslog('info', '%s', 'this is another test');
120 syslog('mail|warning', 'this is a better test: %d', time);
123 syslog('debug', 'this is the last test');
126 openlog("$program $$", 'ndelay', 'user');
127 syslog('notice', 'fooprogram: this is really done');
131 syslog('info', 'problem was %m'); # %m == $! in syslog(3)
133 # Log to UDP port on $remotehost instead of logging locally
135 $Sys::Syslog::host = $remotehost;
136 openlog($program, 'ndelay', 'user');
137 syslog('info', 'something happened over here');
145 Tom Christiansen E<lt>F<tchrist@perl.com>E<gt> and Larry Wall
146 E<lt>F<larry@wall.org>E<gt>.
148 UNIX domain sockets added by Sean Robinson
149 E<lt>F<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
150 E<lt>F<Tim.Bunce@ig.co.uk>E<gt> and the perl5-porters mailing list.
152 Dependency on F<syslog.ph> replaced with XS code by Tom Hughes
153 E<lt>F<tom@compton.nu>E<gt>.
155 Code for constant()s regenerated by Nicholas Clark E<lt>F<nick@ccl4.org>E<gt>.
157 Failover to different communication modes by Nick Williams
158 E<lt>F<Nick.Williams@morganstanley.com>E<gt>.
163 # This AUTOLOAD is used to 'autoload' constants from the constant()
168 ($constname = $AUTOLOAD) =~ s/.*:://;
169 croak "&Sys::Syslog::constant not defined" if $constname eq 'constant';
170 my ($error, $val) = constant($constname);
175 *$AUTOLOAD = sub { $val };
180 XSLoader::load('Sys::Syslog', $VERSION);
182 our $maskpri = &LOG_UPTO(&LOG_DEBUG);
185 our ($ident, $logopt, $facility) = @_; # package vars
186 our $lo_pid = $logopt =~ /\bpid\b/;
187 our $lo_ndelay = $logopt =~ /\bndelay\b/;
188 our $lo_nowait = $logopt =~ /\bnowait\b/;
189 return 1 unless $lo_ndelay;
194 our $facility = our $ident = '';
199 my $oldmask = $maskpri;
206 $syslog_path = shift;
207 &disconnect if $connected;
209 @fallbackMethods = ();
210 @connectMethods = @defaultMethods;
211 if (ref $setsock eq 'ARRAY') {
212 @connectMethods = @$setsock;
213 } elsif (lc($setsock) eq 'stream') {
214 unless (defined $syslog_path) {
215 my @try = qw(/dev/log /dev/conslog);
216 if (length &_PATH_LOG) { # Undefined _PATH_LOG is "".
217 unshift @try, &_PATH_LOG;
225 carp "stream passed to setlogsock, but could not find any device"
226 unless defined $syslog_path;
228 unless (-w $syslog_path) {
229 carp "stream passed to setlogsock, but $syslog_path is not writable";
232 @connectMethods = ( 'stream' );
234 } elsif (lc($setsock) eq 'unix') {
235 if (length _PATH_LOG() && !defined $syslog_path) {
236 $syslog_path = _PATH_LOG();
237 @connectMethods = ( 'unix' );
239 carp 'unix passed to setlogsock, but path not available';
242 } elsif (lc($setsock) eq 'tcp') {
243 if (getservbyname('syslog', 'tcp') || getservbyname('syslogng', 'tcp')) {
244 @connectMethods = ( 'tcp' );
246 carp "tcp passed to setlogsock, but tcp service unavailable";
249 } elsif (lc($setsock) eq 'udp') {
250 if (getservbyname('syslog', 'udp')) {
251 @connectMethods = ( 'udp' );
253 carp "udp passed to setlogsock, but udp service unavailable";
256 } elsif (lc($setsock) eq 'inet') {
257 @connectMethods = ( 'tcp', 'udp' );
258 } elsif (lc($setsock) eq 'console') {
259 @connectMethods = ( 'console' );
261 carp "Invalid argument passed to setlogsock; must be 'stream', 'unix', 'tcp', 'udp' or 'inet'";
267 my $priority = shift;
269 my ($message, $whoami);
270 my (@words, $num, $numpri, $numfac, $sum);
272 local($facility) = $facility; # may need to change temporarily.
274 croak "syslog: expecting argument \$priority" unless $priority;
275 croak "syslog: expecting argument \$format" unless $mask;
277 @words = split(/\W+/, $priority, 2);# Allow "level" or "level|facility".
281 $num = &xlate($_); # Translate word to number.
282 if (/^kern$/ || $num < 0) {
283 croak "syslog: invalid level/facility: $_";
285 elsif ($num <= &LOG_PRIMASK) {
286 croak "syslog: too many levels given: $_" if defined($numpri);
288 return 0 unless &LOG_MASK($numpri) & $maskpri;
291 croak "syslog: too many facilities given: $_" if defined($numfac);
297 croak "syslog: level must be given" unless defined($numpri);
299 if (!defined($numfac)) { # Facility not specified in this call.
300 $facility = 'user' unless $facility;
301 $numfac = &xlate($facility);
304 &connect unless $connected;
306 $whoami = our $ident;
308 if (!$whoami && $mask =~ /^(\S.*?):\s?(.*)/) {
314 ($whoami = getlogin) ||
315 ($whoami = getpwuid($<)) ||
316 ($whoami = 'syslog');
319 $whoami .= "[$$]" if our $lo_pid;
321 $mask =~ s/(?<!%)%m/$!/g;
322 $mask .= "\n" unless $mask =~ /\n$/;
323 $message = sprintf ($mask, @_);
325 $sum = $numpri + $numfac;
326 my $buf = "<$sum>$whoami: $message\0";
328 # it's possible that we'll get an error from sending
329 # (e.g. if method is UDP and there is no UDP listener,
330 # then we'll get ECONNREFUSED on the send). So what we
331 # want to do at this point is to fallback onto a different
333 while (scalar @fallbackMethods || $syslog_send) {
334 if ($failed && (time - $fail_time) > 60) {
335 # it's been a while... maybe things have been fixed
336 @fallbackMethods = ();
338 $transmit_ok = 0; # make it look like a fresh attempt
341 if ($connected && !connection_ok()) {
342 # Something was OK, but has now broken. Remember coz we'll
343 # want to go back to what used to be OK.
344 $failed = $current_proto unless $failed;
348 &connect unless $connected;
349 $failed = undef if ($current_proto && $failed && $current_proto eq $failed);
351 if (&{$syslog_send}($buf)) {
355 # typically doesn't happen, since errors are rare from write().
359 # could not send, could not fallback onto a working
360 # connection method. Lose.
364 sub _syslog_send_console {
366 chop($buf); # delete the NUL from the end
367 # The console print is a method which could block
368 # so we do it in a child process and always return success
370 if (my $pid = fork) {
375 if (waitpid($pid, 0) >= 0) {
378 # it's possible that the caller has other
379 # plans for SIGCHLD, so let's not interfere
384 if (open(CONS, ">/dev/console")) {
385 my $ret = print CONS $buf . "\r";
386 exit ($ret) if defined $pid;
389 exit if defined $pid;
393 sub _syslog_send_stream {
395 # XXX: this only works if the OS stream implementation makes a write
396 # look like a putmsg() with simple header. For instance it works on
397 # Solaris 8 but not Solaris 7.
398 # To be correct, it should use a STREAMS API, but perl doesn't have one.
399 return syswrite(SYSLOG, $buf, length($buf));
401 sub _syslog_send_socket {
403 return syswrite(SYSLOG, $buf, length($buf));
404 #return send(SYSLOG, $buf, 0);
409 return $name+0 if $name =~ /^\s*\d+\s*$/;
411 $name = "LOG_$name" unless $name =~ /^LOG_/;
412 $name = "Sys::Syslog::$name";
413 # Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
414 my $value = eval { no strict 'refs'; &$name };
415 defined $value ? $value : -1;
419 @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
420 if ($transmit_ok && $current_proto) {
421 # Retry what we were on, because it's worked in the past.
422 unshift(@fallbackMethods, $current_proto);
427 while ($proto = shift(@fallbackMethods)) {
429 my $fn = "connect_$proto";
430 $connected = &$fn(\@errs) if defined &$fn;
431 last if ($connected);
436 $current_proto = $proto;
437 my($old) = select(SYSLOG); $| = 1; select($old);
439 @fallbackMethods = ();
440 foreach my $err (@errs) {
443 croak "no connection to syslog available";
450 require Sys::Hostname;
451 my($host_uniq) = Sys::Hostname::hostname();
452 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
454 my $tcp = getprotobyname('tcp');
456 push(@{$errs}, "getprotobyname failed for tcp");
459 my $syslog = getservbyname('syslog','tcp');
460 $syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
461 if (!defined $syslog) {
462 push(@{$errs}, "getservbyname failed for tcp");
466 my $this = sockaddr_in($syslog, INADDR_ANY);
467 my $that = sockaddr_in($syslog, inet_aton($host));
469 push(@{$errs}, "can't lookup $host");
472 if (!socket(SYSLOG,AF_INET,SOCK_STREAM,$tcp)) {
473 push(@{$errs}, "tcp socket: $!");
476 setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
477 setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
478 if (!CORE::connect(SYSLOG,$that)) {
479 push(@{$errs}, "tcp connect: $!");
482 $syslog_send = \&_syslog_send_socket;
489 require Sys::Hostname;
490 my($host_uniq) = Sys::Hostname::hostname();
491 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
493 my $udp = getprotobyname('udp');
495 push(@{$errs}, "getprotobyname failed for udp");
498 my $syslog = getservbyname('syslog','udp');
499 if (!defined $syslog) {
500 push(@{$errs}, "getservbyname failed for udp");
503 my $this = sockaddr_in($syslog, INADDR_ANY);
504 my $that = sockaddr_in($syslog, inet_aton($host));
506 push(@{$errs}, "can't lookup $host");
509 if (!socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp)) {
510 push(@{$errs}, "udp socket: $!");
513 if (!CORE::connect(SYSLOG,$that)) {
514 push(@{$errs}, "udp connect: $!");
517 # We want to check that the UDP connect worked. However the only
518 # way to do that is to send a message and see if an ICMP is returned
519 _syslog_send_socket("");
520 if (!connection_ok()) {
521 push(@{$errs}, "udp connect: nobody listening");
524 $syslog_send = \&_syslog_send_socket;
530 # might want syslog_path to be variable based on syslog.h (if only
532 $syslog_path = '/dev/conslog';
533 if (!-w $syslog_path) {
534 push(@{$errs}, "stream $syslog_path is not writable");
537 if (!open(SYSLOG, ">" . $syslog_path)) {
538 push(@{$errs}, "stream can't open $syslog_path: $!");
541 $syslog_send = \&_syslog_send_stream;
547 if (length _PATH_LOG()) {
548 $syslog_path = _PATH_LOG();
550 push(@{$errs}, "_PATH_LOG not available in syslog.h");
553 my $that = sockaddr_un($syslog_path);
555 push(@{$errs}, "can't locate $syslog_path");
558 if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
559 push(@{$errs}, "unix stream socket: $!");
562 if (!CORE::connect(SYSLOG,$that)) {
563 if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
564 push(@{$errs}, "unix dgram socket: $!");
567 if (!CORE::connect(SYSLOG,$that)) {
568 push(@{$errs}, "unix dgram connect: $!");
572 $syslog_send = \&_syslog_send_socket;
576 sub connect_console {
578 if (!-w '/dev/console') {
579 push(@{$errs}, "console is not writable");
582 $syslog_send = \&_syslog_send_console;
586 # to test if the connection is still good, we need to check if any
587 # errors are present on the connection. The errors will not be raised
588 # by a write. Instead, sockets are made readable and the next read
589 # would cause the error to be returned. Unfortunately the syslog
590 # 'protocol' never provides anything for us to read. But with
591 # judicious use of select(), we can see if it would be readable...
593 return 1 if (defined $current_proto && $current_proto eq 'console');
595 vec($rin, fileno(SYSLOG), 1) = 1;
596 my $ret = select $rin, undef, $rin, 0;
597 return ($ret ? 0 : 1);
603 $syslog_send = undef;