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 $message as
81 the formatting string to sprintf() even when no formatting arguments
82 where provided. If the code calling syslog() might execute with older
83 versions of this module, make sure to call the function as
84 syslog($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;
331 $mask =~ s/(?<!%)%m/$!/g;
332 $mask .= "\n" unless $mask =~ /\n$/;
333 $message = @_ ? sprintf($mask, @_) : $mask;
335 $sum = $numpri + $numfac;
336 my $buf = "<$sum>$whoami: $message\0";
338 # it's possible that we'll get an error from sending
339 # (e.g. if method is UDP and there is no UDP listener,
340 # then we'll get ECONNREFUSED on the send). So what we
341 # want to do at this point is to fallback onto a different
343 while (scalar @fallbackMethods || $syslog_send) {
344 if ($failed && (time - $fail_time) > 60) {
345 # it's been a while... maybe things have been fixed
346 @fallbackMethods = ();
348 $transmit_ok = 0; # make it look like a fresh attempt
351 if ($connected && !connection_ok()) {
352 # Something was OK, but has now broken. Remember coz we'll
353 # want to go back to what used to be OK.
354 $failed = $current_proto unless $failed;
358 &connect unless $connected;
359 $failed = undef if ($current_proto && $failed && $current_proto eq $failed);
361 if (&{$syslog_send}($buf)) {
365 # typically doesn't happen, since errors are rare from write().
369 # could not send, could not fallback onto a working
370 # connection method. Lose.
374 sub _syslog_send_console {
376 chop($buf); # delete the NUL from the end
377 # The console print is a method which could block
378 # so we do it in a child process and always return success
380 if (my $pid = fork) {
385 if (waitpid($pid, 0) >= 0) {
388 # it's possible that the caller has other
389 # plans for SIGCHLD, so let's not interfere
394 if (open(CONS, ">/dev/console")) {
395 my $ret = print CONS $buf . "\r";
396 exit ($ret) if defined $pid;
399 exit if defined $pid;
403 sub _syslog_send_stream {
405 # XXX: this only works if the OS stream implementation makes a write
406 # look like a putmsg() with simple header. For instance it works on
407 # Solaris 8 but not Solaris 7.
408 # To be correct, it should use a STREAMS API, but perl doesn't have one.
409 return syswrite(SYSLOG, $buf, length($buf));
411 sub _syslog_send_socket {
413 return syswrite(SYSLOG, $buf, length($buf));
414 #return send(SYSLOG, $buf, 0);
419 return $name+0 if $name =~ /^\s*\d+\s*$/;
421 $name = "LOG_$name" unless $name =~ /^LOG_/;
422 $name = "Sys::Syslog::$name";
423 # Can't have just eval { &$name } || -1 because some LOG_XXX may be zero.
424 my $value = eval { no strict 'refs'; &$name };
425 defined $value ? $value : -1;
429 @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
430 if ($transmit_ok && $current_proto) {
431 # Retry what we were on, because it's worked in the past.
432 unshift(@fallbackMethods, $current_proto);
437 while ($proto = shift(@fallbackMethods)) {
439 my $fn = "connect_$proto";
440 $connected = &$fn(\@errs) if defined &$fn;
441 last if ($connected);
446 $current_proto = $proto;
447 my($old) = select(SYSLOG); $| = 1; select($old);
449 @fallbackMethods = ();
450 foreach my $err (@errs) {
453 croak "no connection to syslog available";
460 require Sys::Hostname;
461 my($host_uniq) = Sys::Hostname::hostname();
462 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
464 my $tcp = getprotobyname('tcp');
466 push(@{$errs}, "getprotobyname failed for tcp");
469 my $syslog = getservbyname('syslog','tcp');
470 $syslog = getservbyname('syslogng','tcp') unless (defined $syslog);
471 if (!defined $syslog) {
472 push(@{$errs}, "getservbyname failed for tcp");
476 my $this = sockaddr_in($syslog, INADDR_ANY);
477 my $that = sockaddr_in($syslog, inet_aton($host));
479 push(@{$errs}, "can't lookup $host");
482 if (!socket(SYSLOG,AF_INET,SOCK_STREAM,$tcp)) {
483 push(@{$errs}, "tcp socket: $!");
486 setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
487 setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
488 if (!CORE::connect(SYSLOG,$that)) {
489 push(@{$errs}, "tcp connect: $!");
492 $syslog_send = \&_syslog_send_socket;
499 require Sys::Hostname;
500 my($host_uniq) = Sys::Hostname::hostname();
501 ($host) = $host_uniq =~ /([A-Za-z0-9_.-]+)/; # allow FQDN (inc _)
503 my $udp = getprotobyname('udp');
505 push(@{$errs}, "getprotobyname failed for udp");
508 my $syslog = getservbyname('syslog','udp');
509 if (!defined $syslog) {
510 push(@{$errs}, "getservbyname failed for udp");
513 my $this = sockaddr_in($syslog, INADDR_ANY);
514 my $that = sockaddr_in($syslog, inet_aton($host));
516 push(@{$errs}, "can't lookup $host");
519 if (!socket(SYSLOG,AF_INET,SOCK_DGRAM,$udp)) {
520 push(@{$errs}, "udp socket: $!");
523 if (!CORE::connect(SYSLOG,$that)) {
524 push(@{$errs}, "udp connect: $!");
527 # We want to check that the UDP connect worked. However the only
528 # way to do that is to send a message and see if an ICMP is returned
529 _syslog_send_socket("");
530 if (!connection_ok()) {
531 push(@{$errs}, "udp connect: nobody listening");
534 $syslog_send = \&_syslog_send_socket;
540 # might want syslog_path to be variable based on syslog.h (if only
542 $syslog_path = '/dev/conslog';
543 if (!-w $syslog_path) {
544 push(@{$errs}, "stream $syslog_path is not writable");
547 if (!open(SYSLOG, ">" . $syslog_path)) {
548 push(@{$errs}, "stream can't open $syslog_path: $!");
551 $syslog_send = \&_syslog_send_stream;
557 if (length _PATH_LOG()) {
558 $syslog_path = _PATH_LOG();
560 push(@{$errs}, "_PATH_LOG not available in syslog.h");
563 my $that = sockaddr_un($syslog_path);
565 push(@{$errs}, "can't locate $syslog_path");
568 if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
569 push(@{$errs}, "unix stream socket: $!");
572 if (!CORE::connect(SYSLOG,$that)) {
573 if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
574 push(@{$errs}, "unix dgram socket: $!");
577 if (!CORE::connect(SYSLOG,$that)) {
578 push(@{$errs}, "unix dgram connect: $!");
582 $syslog_send = \&_syslog_send_socket;
586 sub connect_console {
588 if (!-w '/dev/console') {
589 push(@{$errs}, "console is not writable");
592 $syslog_send = \&_syslog_send_console;
596 # to test if the connection is still good, we need to check if any
597 # errors are present on the connection. The errors will not be raised
598 # by a write. Instead, sockets are made readable and the next read
599 # would cause the error to be returned. Unfortunately the syslog
600 # 'protocol' never provides anything for us to read. But with
601 # judicious use of select(), we can see if it would be readable...
603 return 1 if (defined $current_proto && $current_proto eq 'console');
605 vec($rin, fileno(SYSLOG), 1) = 1;
606 my $ret = select $rin, undef, $rin, 0;
607 return ($ret ? 0 : 1);
613 $syslog_send = undef;