@EXPORT_OK = qw(setlogsock);
$VERSION = '0.02';
+# 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 = ( 'stream', 'unix', 'tcp', 'udp' );
+my @connectMethods = ( 'tcp', 'udp', 'unix', 'stream', 'console' );
+my @defaultMethods = @connectMethods;
+my $syslog_path = undef;
+my $transmit_ok = 0;
+my $current_proto = undef;
+my $failed = undef;
+my $fail_time = undef;
+
use Socket;
use Sys::Hostname;
# 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
=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
+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
=item syslog $priority, $format, @args
Sets log mask I<$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 returned by
+the C<_PATH_LOG> macro (if your system defines it) in F<syslog.ph>. A
+value of 'stream' will connect to the stream indicated by the pathname
+provided as the optional second parameter. 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 for the INET socket to be used.
+The default is to try tcp, udp, unix, stream, console.
+
+Giving an invalid value for sock_type will croak.
=item closelog
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<Tim.Bunce@ig.co.uk>E<gt> and the perl5-porters mailing list.
+E<lt>F<robinson_s@sc.maricopa.edu>E<gt> with support from Tim Bunce
+E<lit>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>nick@ccl4.orgE<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 = $AUTOLOAD) =~ s/.*:://;
($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/;
return 1 unless $lo_ndelay;
&connect;
sub setlogsock {
local($setsock) = shift;
+ $syslog_path = shift;
&disconnect if $connected;
- if (lc($setsock) eq 'unix') {
- if (length _PATH_LOG()) {
- $sock_type = 1;
+ $transmit_ok = 0;
+ @fallbackMethods = ();
+ @connectMethods = @defaultMethods;
+ if (ref $setsock eq 'ARRAY') {
+ @connectMethods = @$setsock;
+ } elsif (lc($setsock) eq 'stream') {
+ $syslog_path = '/dev/log' unless($syslog_path);
+ if (!-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') {
- if (getservbyname('syslog','udp')) {
- undef($sock_type);
- } else {
- return undef;
- }
+ @connectMethods = ( 'tcp', 'udp' );
+ } elsif (lc($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;
}
$message = sprintf ($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 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 $pid = fork) {
+ if ($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) = @_;
$name = uc $name;
}
sub connect {
+ @fallbackMethods = @connectMethods unless (scalar @fallbackMethods);
+ if ($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)) {
+ my $fn = "connect_$proto";
+ $connected = &$fn(\@errs) unless (!defined &$fn);
+ last if ($connected);
+ }
+
+ $transmit_ok = 0;
+ if ($connected) {
+ $current_proto = $proto;
+ local($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: $!");
+ return 0;
+ }
+ setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1);
+ setsockopt(SYSLOG, IPPROTO_TCP, TCP_NODELAY, 1);
+ if (!connect(SYSLOG,$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') || croak "getprotobyname failed for udp";
- my $syslog = getservbyname('syslog','udp') || croak "getservbyname failed";
- 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: $!");
+ return 0;
+ }
+ if (!connect(SYSLOG,$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: $!";
+ push(@{$errs}, "_PATH_LOG not available in syslog.h");
+ return 0;
+ }
+ my $that = sockaddr_un($syslog_path);
+ if (!$that) {
+ push(@{$errs}, "can't locate $syslog_path");
+ return 0;
+ }
+ if (!socket(SYSLOG,AF_UNIX,SOCK_STREAM,0)) {
+ push(@{$errs}, "unix stream socket: $!");
+ return 0;
+ }
+ if (!connect(SYSLOG,$that)) {
+ if (!socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0)) {
+ push(@{$errs}, "unix dgram socket: $!");
+ return 0;
+ }
if (!connect(SYSLOG,$that)) {
- socket(SYSLOG,AF_UNIX,SOCK_DGRAM,0) || croak "socket: $!";
- connect(SYSLOG,$that) || croak "connect: $! (SOCK_DGRAM after trying SOCK_STREAM)";
- }
+ push(@{$errs}, "unix dgram connect: $!");
+ return 0;
+ }
}
- local($old) = select(SYSLOG); $| = 1; select($old);
- $connected = 1;
+ $syslog_send = \&_syslog_send_socket;
+ return 1;
+}
+
+sub connect_console {
+ my ($errs) = @_;
+ if (!-w '/dev/console') {
+ push(@{$errs}, "console is not writable");
+ return 0;
+ }
+ $syslog_send = \&_syslog_send_console;
+ return 1;
+}
+
+# to test if the connection is still good, we need to check if any
+# errors are present on the connection. The errors will not be raised
+# by a write. Instead, sockets are made readable and the next read
+# would cause the error to be returned. Unfortunately the syslog
+# 'protocol' never provides anything for us to read. But with
+# judicious use of select(), we can see if it would be readable...
+sub connection_ok {
+ return 1 if ($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;
projects / p5sagit/p5-mst-13.2.git / commitdiff