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Edit File: Syslog.pm
package Sys::Syslog; use strict; use warnings; use warnings::register; use Carp; use Config; use Exporter (); use File::Basename; use POSIX qw< strftime setlocale LC_TIME >; use Socket qw< :all >; require 5.005; *import = \&Exporter::import; { no strict 'vars'; $VERSION = '0.35'; %EXPORT_TAGS = ( standard => [qw(openlog syslog closelog setlogmask)], extended => [qw(setlogsock)], macros => [ # levels qw( LOG_ALERT LOG_CRIT LOG_DEBUG LOG_EMERG LOG_ERR LOG_INFO LOG_NOTICE LOG_WARNING ), # standard facilities qw( LOG_AUTH LOG_AUTHPRIV LOG_CRON LOG_DAEMON LOG_FTP LOG_KERN LOG_LOCAL0 LOG_LOCAL1 LOG_LOCAL2 LOG_LOCAL3 LOG_LOCAL4 LOG_LOCAL5 LOG_LOCAL6 LOG_LOCAL7 LOG_LPR LOG_MAIL LOG_NEWS LOG_SYSLOG LOG_USER LOG_UUCP ), # Mac OS X specific facilities qw( LOG_INSTALL LOG_LAUNCHD LOG_NETINFO LOG_RAS LOG_REMOTEAUTH ), # modern BSD specific facilities qw( LOG_CONSOLE LOG_NTP LOG_SECURITY ), # IRIX specific facilities qw( LOG_AUDIT LOG_LFMT ), # options qw( LOG_CONS LOG_PID LOG_NDELAY LOG_NOWAIT LOG_ODELAY LOG_PERROR ), # others macros qw( LOG_FACMASK LOG_NFACILITIES LOG_PRIMASK LOG_MASK LOG_UPTO ), ], ); @EXPORT = ( @{$EXPORT_TAGS{standard}}, ); @EXPORT_OK = ( @{$EXPORT_TAGS{extended}}, @{$EXPORT_TAGS{macros}}, ); eval { require XSLoader; XSLoader::load('Sys::Syslog', $VERSION); 1 } or do { require DynaLoader; push @ISA, 'DynaLoader'; bootstrap Sys::Syslog $VERSION; }; } # # Constants # use constant HAVE_GETPROTOBYNAME => $Config::Config{d_getpbyname}; use constant HAVE_GETPROTOBYNUMBER => $Config::Config{d_getpbynumber}; use constant HAVE_SETLOCALE => $Config::Config{d_setlocale}; use constant HAVE_IPPROTO_TCP => defined &Socket::IPPROTO_TCP ? 1 : 0; use constant HAVE_IPPROTO_UDP => defined &Socket::IPPROTO_UDP ? 1 : 0; use constant HAVE_TCP_NODELAY => defined &Socket::TCP_NODELAY ? 1 : 0; use constant SOCKET_IPPROTO_TCP => HAVE_IPPROTO_TCP ? Socket::IPPROTO_TCP : HAVE_GETPROTOBYNAME ? scalar getprotobyname("tcp") : 6; use constant SOCKET_IPPROTO_UDP => HAVE_IPPROTO_UDP ? Socket::IPPROTO_UDP : HAVE_GETPROTOBYNAME ? scalar getprotobyname("udp") : 17; use constant SOCKET_TCP_NODELAY => HAVE_TCP_NODELAY ? Socket::TCP_NODELAY : 1; # # Public variables # use vars qw($host); # host to send syslog messages to (see notes at end) # # Prototypes # sub silent_eval (&); # # Global variables # use vars qw($facility); my $connected = 0; # flag to indicate if we're connected or not my $syslog_send; # coderef of the function used to send messages my $syslog_path = undef; # syslog path for "stream" and "unix" mechanisms my $syslog_xobj = undef; # if defined, holds the external object used to send messages my $transmit_ok = 0; # flag to indicate if the last message was transmitted my $sock_port = undef; # socket port my $sock_timeout = 0; # socket timeout, see below my $current_proto = undef; # current mechanism used to transmit messages my $ident = ''; # identifiant prepended to each message $facility = ''; # current facility my $maskpri = LOG_UPTO(&LOG_DEBUG); # current log mask my %options = ( ndelay => 0, noeol => 0, nofatal => 0, nonul => 0, nowait => 0, perror => 0, pid => 0, ); # Default is now to first use the native mechanism, so Perl programs # behave like other normal Unix programs, then try other mechanisms. my @connectMethods = qw(native tcp udp unix pipe stream console); if ($^O eq "freebsd" or $^O eq "linux") { @connectMethods = grep { $_ ne 'udp' } @connectMethods; } # And on Win32 systems, we try to use the native mechanism for this # platform, the events logger, available through Win32::EventLog. EVENTLOG: { my $verbose_if_Win32 = $^O =~ /Win32/i; if (can_load_sys_syslog_win32($verbose_if_Win32)) { unshift @connectMethods, 'eventlog'; } } my @defaultMethods = @connectMethods; my @fallbackMethods = (); # The timeout in connection_ok() was pushed up to 0.25 sec in # Sys::Syslog v0.19 in order to address a heisenbug on MacOSX: # http://london.pm.org/pipermail/london.pm/Week-of-Mon-20061211/005961.html # # However, this also had the effect of slowing this test for # all other operating systems, which apparently impacted some # users (cf. CPAN-RT #34753). So, in order to make everybody # happy, the timeout is now zero by default on all systems # except on OSX where it is set to 250 msec, and can be set # with the infamous setlogsock() function. # # Update 2011-08: this issue is also been seen on multiprocessor # Debian GNU/kFreeBSD systems. See http://bugs.debian.org/627821 # and https://rt.cpan.org/Ticket/Display.html?id=69997 # Also, lowering the delay to 1 ms, which should be enough. $sock_timeout = 0.001 if $^O =~ /darwin|gnukfreebsd/; # Perl 5.6.0's warnings.pm doesn't have warnings::warnif() if (not defined &warnings::warnif) { *warnings::warnif = sub { goto &warnings::warn if warnings::enabled(__PACKAGE__) } } # coderef for a nicer handling of errors my $err_sub = $options{nofatal} ? \&warnings::warnif : \&croak; sub AUTOLOAD { # This AUTOLOAD is used to 'autoload' constants from the constant() # XS function. no strict 'vars'; my $constname; ($constname = $AUTOLOAD) =~ s/.*:://; croak "Sys::Syslog::constant() not defined" if $constname eq 'constant'; my ($error, $val) = constant($constname); croak $error if $error; no strict 'refs'; *$AUTOLOAD = sub { $val }; goto &$AUTOLOAD; } sub openlog { ($ident, my $logopt, $facility) = @_; # default values $ident ||= basename($0) || getlogin() || getpwuid($<) || 'syslog'; $logopt ||= ''; $facility ||= LOG_USER(); for my $opt (split /\b/, $logopt) { $options{$opt} = 1 if exists $options{$opt} } $err_sub = delete $options{nofatal} ? \&warnings::warnif : \&croak; return 1 unless $options{ndelay}; connect_log(); } sub closelog { disconnect_log() if $connected; $options{$_} = 0 for keys %options; $facility = $ident = ""; $connected = 0; return 1 } sub setlogmask { my $oldmask = $maskpri; $maskpri = shift unless $_[0] == 0; $oldmask; } my %mechanism = ( console => { check => sub { 1 }, }, eventlog => { check => sub { return can_load_sys_syslog_win32() }, err_msg => "no Win32 API available", }, inet => { check => sub { 1 }, }, native => { check => sub { 1 }, }, pipe => { check => sub { ($syslog_path) = grep { defined && length && -p && -w _ } $syslog_path, &_PATH_LOG, "/dev/log"; return $syslog_path ? 1 : 0 }, err_msg => "path not available", }, stream => { check => sub { if (not defined $syslog_path) { my @try = qw(/dev/log /dev/conslog); unshift @try, &_PATH_LOG if length &_PATH_LOG; ($syslog_path) = grep { -w } @try; } return defined $syslog_path && -w $syslog_path }, err_msg => "could not find any writable device", }, tcp => { check => sub { return 1 if defined $sock_port; if (eval { local $SIG{__DIE__}; getservbyname('syslog','tcp') || getservbyname('syslogng','tcp') }) { $host = $syslog_path; return 1 } else { return } }, err_msg => "TCP service unavailable", }, udp => { check => sub { return 1 if defined $sock_port; if (eval { local $SIG{__DIE__}; getservbyname('syslog', 'udp') }) { $host = $syslog_path; return 1 } else { return } }, err_msg => "UDP service unavailable", }, unix => { check => sub { my @try = ($syslog_path, &_PATH_LOG); ($syslog_path) = grep { defined && length && -w } @try; return defined $syslog_path && -w $syslog_path }, err_msg => "path not available", }, ); sub setlogsock { my %opt; # handle arguments # - old API: setlogsock($sock_type, $sock_path, $sock_timeout) # - new API: setlogsock(\%options) croak "setlogsock(): Invalid number of arguments" unless @_ >= 1 and @_ <= 3; if (my $ref = ref $_[0]) { if ($ref eq "HASH") { %opt = %{ $_[0] }; croak "setlogsock(): No argument given" unless keys %opt; } elsif ($ref eq "ARRAY") { @opt{qw< type path timeout >} = @_; } else { croak "setlogsock(): Unexpected \L$ref\E reference" } } else { @opt{qw< type path timeout >} = @_; } # check socket type, remove invalid ones my $diag_invalid_type = "setlogsock(): Invalid type%s; must be one of " . join ", ", map { "'$_'" } sort keys %mechanism; croak sprintf $diag_invalid_type, "" unless defined $opt{type}; my @sock_types = ref $opt{type} eq "ARRAY" ? @{$opt{type}} : ($opt{type}); my @tmp; for my $sock_type (@sock_types) { carp sprintf $diag_invalid_type, " '$sock_type'" and next unless exists $mechanism{$sock_type}; push @tmp, "tcp", "udp" and next if $sock_type eq "inet"; push @tmp, $sock_type; } @sock_types = @tmp; # set global options $syslog_path = $opt{path} if defined $opt{path}; $host = $opt{host} if defined $opt{host}; $sock_timeout = $opt{timeout} if defined $opt{timeout}; $sock_port = $opt{port} if defined $opt{port}; disconnect_log() if $connected; $transmit_ok = 0; @fallbackMethods = (); @connectMethods = (); my $found = 0; # check each given mechanism and test if it can be used on the current system for my $sock_type (@sock_types) { if ( $mechanism{$sock_type}{check}->() ) { push @connectMethods, $sock_type; $found = 1; } else { warnings::warnif("setlogsock(): type='$sock_type': " . $mechanism{$sock_type}{err_msg}); } } # if no mechanism worked from the given ones, use the default ones @connectMethods = @defaultMethods unless @connectMethods; return $found; } sub syslog { my ($priority, $mask, @args) = @_; my ($message, $buf); my (@words, $num, $numpri, $numfac, $sum); my $failed = undef; my $fail_time = undef; my $error = $!; # if $ident is undefined, it means openlog() wasn't previously called # so do it now in order to have sensible defaults openlog() unless $ident; local $facility = $facility; # may need to change temporarily. croak "syslog: expecting argument \$priority" unless defined $priority; croak "syslog: expecting argument \$format" unless defined $mask; if ($priority =~ /^\d+$/) { $numpri = LOG_PRI($priority); $numfac = LOG_FAC($priority) << 3; undef $numfac if $numfac == 0; # no facility given => use default } elsif ($priority =~ /^\w+/) { # Allow "level" or "level|facility". @words = split /\W+/, $priority, 2; undef $numpri; undef $numfac; for my $word (@words) { next if length $word == 0; # Translate word to number. $num = xlate($word); if ($num < 0) { croak "syslog: invalid level/facility: $word" } elsif ($num <= LOG_PRIMASK() and $word ne "kern") { croak "syslog: too many levels given: $word" if defined $numpri; $numpri = $num; } else { croak "syslog: too many facilities given: $word" if defined $numfac; $facility = $word if $word =~ /^[A-Za-z]/; $numfac = $num; } } } else { croak "syslog: invalid level/facility: $priority" } croak "syslog: level must be given" unless defined $numpri; # don't log if priority is below mask level return 0 unless LOG_MASK($numpri) & $maskpri; if (not defined $numfac) { # Facility not specified in this call. $facility = 'user' unless $facility; $numfac = xlate($facility); } connect_log() unless $connected; if ($mask =~ /%m/) { # escape percent signs for sprintf() $error =~ s/%/%%/g if @args; # replace %m with $error, if preceded by an even number of percent signs $mask =~ s/(?<!%)((?:%%)*)%m/$1$error/g; } # add (or not) a newline $mask .= "\n" if !$options{noeol} and rindex($mask, "\n") == -1; $message = @args ? sprintf($mask, @args) : $mask; if ($current_proto eq 'native') { $buf = $message; } elsif ($current_proto eq 'eventlog') { $buf = $message; } else { my $whoami = $ident; $whoami .= "[$$]" if $options{pid}; $sum = $numpri + $numfac; my $oldlocale; if (HAVE_SETLOCALE) { $oldlocale = setlocale(LC_TIME); setlocale(LC_TIME, 'C'); } # %e format isn't available on all systems (Win32, cf. CPAN RT #69310) my $day = strftime "%e", localtime; if (index($day, "%") == 0) { $day = strftime "%d", localtime; $day =~ s/^0/ /; } my $timestamp = strftime "%b $day %H:%M:%S", localtime; setlocale(LC_TIME, $oldlocale) if HAVE_SETLOCALE; # construct the stream that will be transmitted $buf = "<$sum>$timestamp $whoami: $message"; # add (or not) a NUL character $buf .= "\0" if !$options{nonul}; } # handle PERROR option # "native" mechanism already handles it by itself if ($options{perror} and $current_proto ne 'native') { my $whoami = $ident; $whoami .= "[$$]" if $options{pid}; print STDERR "$whoami: $message"; print STDERR "\n" if rindex($message, "\n") == -1; } # 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_log(); $transmit_ok = 0; # make it look like a fresh attempt connect_log(); } if ($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_log(); } connect_log() unless $connected; $failed = undef if ($current_proto && $failed && $current_proto eq $failed); if ($syslog_send) { if ($syslog_send->($buf, $numpri, $numfac)) { $transmit_ok++; return 1; } # typically doesn't happen, since errors are rare from write(). disconnect_log(); } } # could not send, could not fallback onto a working # connection method. Lose. return 0; } sub _syslog_send_console { my ($buf) = @_; # 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 $pid = fork) { if ($options{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 $buf . "\r"; # XXX: should this be \x0A ? POSIX::_exit($ret) if defined $pid; close CONS; } POSIX::_exit(0) 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_pipe { my ($buf) = @_; return print SYSLOG $buf; } sub _syslog_send_socket { my ($buf) = @_; return syswrite(SYSLOG, $buf, length($buf)); #return send(SYSLOG, $buf, 0); } sub _syslog_send_native { my ($buf, $numpri, $numfac) = @_; syslog_xs($numpri|$numfac, $buf); return 1; } # xlate() # ----- # private function to translate names to numeric values # sub xlate { my ($name) = @_; return $name+0 if $name =~ /^\s*\d+\s*$/; $name = uc $name; $name = "LOG_$name" unless $name =~ /^LOG_/; # ExtUtils::Constant 0.20 introduced a new way to implement # constants, called ProxySubs. When it was used to generate # the C code, the constant() function no longer returns the # correct value. Therefore, we first try a direct call to # constant(), and if the value is an error we try to call the # constant by its full name. my $value = constant($name); if (index($value, "not a valid") >= 0) { $name = "Sys::Syslog::$name"; $value = eval { no strict "refs"; &$name }; $value = $@ unless defined $value; } $value = -1 if index($value, "not a valid") >= 0; return defined $value ? $value : -1; } # connect_log() # ----------- # This function acts as a kind of front-end: it tries to connect to # a syslog service using the selected methods, trying each one in the # selected order. # sub connect_log { @fallbackMethods = @connectMethods unless scalar @fallbackMethods; if ($transmit_ok && $current_proto) { # Retry what we were on, because it has worked in the past. unshift(@fallbackMethods, $current_proto); } $connected = 0; my @errs = (); my $proto = undef; while ($proto = shift @fallbackMethods) { no strict 'refs'; my $fn = "connect_$proto"; $connected = &$fn(\@errs) if defined &$fn; last if $connected; } $transmit_ok = 0; if ($connected) { $current_proto = $proto; my ($old) = select(SYSLOG); $| = 1; select($old); } else { @fallbackMethods = (); $err_sub->(join "\n\t- ", "no connection to syslog available", @errs); return undef; } } sub connect_tcp { my ($errs) = @_; my $port = $sock_port || eval { local $SIG{__DIE__}; getservbyname('syslog', 'tcp') } || eval { local $SIG{__DIE__}; getservbyname('syslogng', 'tcp') }; if (!defined $port) { push @$errs, "getservbyname failed for syslog/tcp and syslogng/tcp"; return 0; } my $addr; if (defined $host) { $addr = inet_aton($host); if (!$addr) { push @$errs, "can't lookup $host"; return 0; } } else { $addr = INADDR_LOOPBACK; } $addr = sockaddr_in($port, $addr); if (!socket(SYSLOG, AF_INET, SOCK_STREAM, SOCKET_IPPROTO_TCP)) { push @$errs, "tcp socket: $!"; return 0; } setsockopt(SYSLOG, SOL_SOCKET, SO_KEEPALIVE, 1); setsockopt(SYSLOG, SOCKET_IPPROTO_TCP, SOCKET_TCP_NODELAY, 1); if (!connect(SYSLOG, $addr)) { push @$errs, "tcp connect: $!"; return 0; } $syslog_send = \&_syslog_send_socket; return 1; } sub connect_udp { my ($errs) = @_; my $port = $sock_port || eval { local $SIG{__DIE__}; getservbyname('syslog', 'udp') }; if (!defined $port) { push @$errs, "getservbyname failed for syslog/udp"; return 0; } my $addr; if (defined $host) { $addr = inet_aton($host); if (!$addr) { push @$errs, "can't lookup $host"; return 0; } } else { $addr = INADDR_LOOPBACK; } $addr = sockaddr_in($port, $addr); if (!socket(SYSLOG, AF_INET, SOCK_DGRAM, SOCKET_IPPROTO_UDP)) { push @$errs, "udp socket: $!"; return 0; } if (!connect(SYSLOG, $addr)) { push @$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' unless defined $syslog_path; if (!-w $syslog_path) { push @$errs, "stream $syslog_path is not writable"; return 0; } require Fcntl; if (!sysopen(SYSLOG, $syslog_path, Fcntl::O_WRONLY(), 0400)) { push @$errs, "stream can't open $syslog_path: $!"; return 0; } $syslog_send = \&_syslog_send_stream; return 1; } sub connect_pipe { my ($errs) = @_; $syslog_path ||= &_PATH_LOG || "/dev/log"; if (not -w $syslog_path) { push @$errs, "$syslog_path is not writable"; return 0; } if (not open(SYSLOG, ">$syslog_path")) { push @$errs, "can't write to $syslog_path: $!"; return 0; } $syslog_send = \&_syslog_send_pipe; return 1; } sub connect_unix { my ($errs) = @_; $syslog_path ||= _PATH_LOG() if length _PATH_LOG(); if (not defined $syslog_path) { push @$errs, "_PATH_LOG not available in syslog.h and no user-supplied socket path"; return 0; } if (not (-S $syslog_path or -c _)) { push @$errs, "$syslog_path is not a socket"; return 0; } my $addr = sockaddr_un($syslog_path); if (!$addr) { push @$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, $addr)) { if (!socket(SYSLOG, AF_UNIX, SOCK_DGRAM, 0)) { push @$errs, "unix dgram socket: $!"; return 0; } if (!connect(SYSLOG, $addr)) { push @$errs, "unix dgram connect: $!"; return 0; } } $syslog_send = \&_syslog_send_socket; return 1; } sub connect_native { my ($errs) = @_; my $logopt = 0; # reconstruct the numeric equivalent of the options for my $opt (keys %options) { $logopt += xlate($opt) if $options{$opt} } openlog_xs($ident, $logopt, xlate($facility)); $syslog_send = \&_syslog_send_native; return 1; } sub connect_eventlog { my ($errs) = @_; $syslog_xobj = Sys::Syslog::Win32::_install(); $syslog_send = \&Sys::Syslog::Win32::_syslog_send; return 1; } sub connect_console { my ($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 defined $current_proto and ( $current_proto eq 'native' or $current_proto eq 'console' or $current_proto eq 'eventlog' ); my $rin = ''; vec($rin, fileno(SYSLOG), 1) = 1; my $ret = select $rin, undef, $rin, $sock_timeout; return ($ret ? 0 : 1); } sub disconnect_log { $connected = 0; $syslog_send = undef; if (defined $current_proto and $current_proto eq 'native') { closelog_xs(); unshift @fallbackMethods, $current_proto; $current_proto = undef; return 1; } elsif (defined $current_proto and $current_proto eq 'eventlog') { $syslog_xobj->Close(); unshift @fallbackMethods, $current_proto; $current_proto = undef; return 1; } return close SYSLOG; } # # Wrappers around eval() that makes sure that nobody, ever knows that # we wanted to poke & test if something was here or not. This is needed # because some applications are trying to be too smart, install their # own __DIE__ handler, and mysteriously, things are starting to fail # when they shouldn't. SpamAssassin among them. # sub silent_eval (&) { local($SIG{__DIE__}, $SIG{__WARN__}, $@); return eval { $_[0]->() } } sub can_load_sys_syslog_win32 { my ($verbose) = @_; local($SIG{__DIE__}, $SIG{__WARN__}, $@); (my $module_path = __FILE__) =~ s:Syslog.pm$:Syslog/Win32.pm:; my $loaded = eval { require $module_path } ? 1 : 0; warn $@ if not $loaded and $verbose; return $loaded } "Eighth Rule: read the documentation." __END__ =head1 NAME Sys::Syslog - Perl interface to the UNIX syslog(3) calls =head1 VERSION This is the documentation of version 0.35 =head1 SYNOPSIS use Sys::Syslog; # all except setlogsock() use Sys::Syslog qw(:standard :macros); # standard functions & macros openlog($ident, $logopt, $facility); # don't forget this syslog($priority, $format, @args); $oldmask = setlogmask($mask_priority); closelog(); =head1 DESCRIPTION C<Sys::Syslog> is an interface to the UNIX C<syslog(3)> program. Call C<syslog()> with a string priority and a list of C<printf()> args just like C<syslog(3)>. =head1 EXPORTS C<Sys::Syslog> exports the following C<Exporter> tags: =over 4 =item * C<:standard> exports the standard C<syslog(3)> functions: openlog closelog setlogmask syslog =item * C<:extended> exports the Perl specific functions for C<syslog(3)>: setlogsock =item * C<:macros> exports the symbols corresponding to most of your C<syslog(3)> macros and the C<LOG_UPTO()> and C<LOG_MASK()> functions. See L<"CONSTANTS"> for the supported constants and their meaning. =back By default, C<Sys::Syslog> exports the symbols from the C<:standard> tag. =head1 FUNCTIONS =over 4 =item B<openlog($ident, $logopt, $facility)> Opens the syslog. C<$ident> is prepended to every message. C<$logopt> contains zero or more of the options detailed below. C<$facility> specifies the part of the system to report about, for example C<LOG_USER> or C<LOG_LOCAL0>: see L<"Facilities"> for a list of well-known facilities, and your C<syslog(3)> documentation for the facilities available in your system. Check L<"SEE ALSO"> for useful links. Facility can be given as a string or a numeric macro. This function will croak if it can't connect to the syslog daemon. Note that C<openlog()> now takes three arguments, just like C<openlog(3)>. B<You should use C<openlog()> before calling C<syslog()>.> B<Options> =over 4 =item * C<cons> - This option is ignored, since the failover mechanism will drop down to the console automatically if all other media fail. =item * C<ndelay> - Open the connection immediately (normally, the connection is opened when the first message is logged). =item * C<noeol> - When set to true, no end of line character (C<\n>) will be appended to the message. This can be useful for some syslog daemons. Added in C<Sys::Syslog> 0.29. =item * C<nofatal> - When set to true, C<openlog()> and C<syslog()> will only emit warnings instead of dying if the connection to the syslog can't be established. Added in C<Sys::Syslog> 0.15. =item * C<nonul> - When set to true, no C<NUL> character (C<\0>) will be appended to the message. This can be useful for some syslog daemons. Added in C<Sys::Syslog> 0.29. =item * C<nowait> - Don't wait for child processes that may have been created while logging the message. (The GNU C library does not create a child process, so this option has no effect on Linux.) =item * C<perror> - Write the message to standard error output as well to the system log. Added in C<Sys::Syslog> 0.22. =item * C<pid> - Include PID with each message. =back B<Examples> Open the syslog with options C<ndelay> and C<pid>, and with facility C<LOCAL0>: openlog($name, "ndelay,pid", "local0"); Same thing, but this time using the macro corresponding to C<LOCAL0>: openlog($name, "ndelay,pid", LOG_LOCAL0); =item B<syslog($priority, $message)> =item B<syslog($priority, $format, @args)> If C<$priority> permits, logs C<$message> or C<sprintf($format, @args)> with the addition that C<%m> in $message or C<$format> is replaced with C<"$!"> (the latest error message). C<$priority> can specify a level, or a level and a facility. Levels and facilities can be given as strings or as macros. When using the C<eventlog> mechanism, priorities C<DEBUG> and C<INFO> are mapped to event type C<informational>, C<NOTICE> and C<WARNING> to C<warning> and C<ERR> to C<EMERG> to C<error>. If you didn't use C<openlog()> before using C<syslog()>, C<syslog()> will try to guess the C<$ident> by extracting the shortest prefix of C<$format> that ends in a C<":">. B<Examples> # informational level syslog("info", $message); syslog(LOG_INFO, $message); # information level, Local0 facility syslog("info|local0", $message); syslog(LOG_INFO|LOG_LOCAL0, $message); =over 4 =item B<Note> C<Sys::Syslog> version v0.07 and older passed the C<$message> as the formatting string to C<sprintf()> even when no formatting arguments were provided. If the code calling C<syslog()> might execute with older versions of this module, make sure to call the function as C<syslog($priority, "%s", $message)> instead of C<syslog($priority, $message)>. This protects against hostile formatting sequences that might show up if $message contains tainted data. =back =item B<setlogmask($mask_priority)> Sets the log mask for the current process to C<$mask_priority> and returns the old mask. If the mask argument is 0, the current log mask is not modified. See L<"Levels"> for the list of available levels. You can use the C<LOG_UPTO()> function to allow all levels up to a given priority (but it only accept the numeric macros as arguments). B<Examples> Only log errors: setlogmask( LOG_MASK(LOG_ERR) ); Log everything except informational messages: setlogmask( ~(LOG_MASK(LOG_INFO)) ); Log critical messages, errors and warnings: setlogmask( LOG_MASK(LOG_CRIT) | LOG_MASK(LOG_ERR) | LOG_MASK(LOG_WARNING) ); Log all messages up to debug: setlogmask( LOG_UPTO(LOG_DEBUG) ); =item B<setlogsock()> Sets the socket type and options to be used for the next call to C<openlog()> or C<syslog()>. Returns true on success, C<undef> on failure. Being Perl-specific, this function has evolved along time. It can currently be called as follow: =over =item * C<setlogsock($sock_type)> =item * C<setlogsock($sock_type, $stream_location)> (added in Perl 5.004_02) =item * C<setlogsock($sock_type, $stream_location, $sock_timeout)> (added in C<Sys::Syslog> 0.25) =item * C<setlogsock(\%options)> (added in C<Sys::Syslog> 0.28) =back The available options are: =over =item * C<type> - equivalent to C<$sock_type>, selects the socket type (or "mechanism"). An array reference can be passed to specify several mechanisms to try, in the given order. =item * C<path> - equivalent to C<$stream_location>, sets the stream location. Defaults to standard Unix location, or C<_PATH_LOG>. =item * C<timeout> - equivalent to C<$sock_timeout>, sets the socket timeout in seconds. Defaults to 0 on all systems except S<Mac OS X> where it is set to 0.25 sec. =item * C<host> - sets the hostname to send the messages to. Defaults to the local host. =item * C<port> - sets the TCP or UDP port to connect to. Defaults to the first standard syslog port available on the system. =back The available mechanisms are: =over =item * C<"native"> - use the native C functions from your C<syslog(3)> library (added in C<Sys::Syslog> 0.15). =item * C<"eventlog"> - send messages to the Win32 events logger (Win32 only; added in C<Sys::Syslog> 0.19). =item * C<"tcp"> - connect to a TCP socket, on the C<syslog/tcp> or C<syslogng/tcp> service. See also the C<host>, C<port> and C<timeout> options. =item * C<"udp"> - connect to a UDP socket, on the C<syslog/udp> service. See also the C<host>, C<port> and C<timeout> options. =item * C<"inet"> - connect to an INET socket, either TCP or UDP, tried in that order. See also the C<host>, C<port> and C<timeout> options. =item * C<"unix"> - connect to a UNIX domain socket (in some systems a character special device). The name of that socket is given by the C<path> option or, if omitted, the value returned by the C<_PATH_LOG> macro (if your system defines it), F</dev/log> or F</dev/conslog>, whichever is writable. =item * C<"stream"> - connect to the stream indicated by the C<path> option, or, if omitted, the value returned by the C<_PATH_LOG> macro (if your system defines it), F</dev/log> or F</dev/conslog>, whichever is writable. For example Solaris and IRIX system may prefer C<"stream"> instead of C<"unix">. =item * C<"pipe"> - connect to the named pipe indicated by the C<path> option, or, if omitted, to the value returned by the C<_PATH_LOG> macro (if your system defines it), or F</dev/log> (added in C<Sys::Syslog> 0.21). HP-UX is a system which uses such a named pipe. =item * C<"console"> - send messages directly to the console, as for the C<"cons"> option of C<openlog()>. =back The default is to try C<native>, C<tcp>, C<udp>, C<unix>, C<pipe>, C<stream>, C<console>. Under systems with the Win32 API, C<eventlog> will be added as the first mechanism to try if C<Win32::EventLog> is available. Giving an invalid value for C<$sock_type> will C<croak>. B<Examples> Select the UDP socket mechanism: setlogsock("udp"); Send messages using the TCP socket mechanism on a custom port: setlogsock({ type => "tcp", port => 2486 }); Send messages to a remote host using the TCP socket mechanism: setlogsock({ type => "tcp", host => $loghost }); Try the native, UDP socket then UNIX domain socket mechanisms: setlogsock(["native", "udp", "unix"]); =over =item B<Note> Now that the "native" mechanism is supported by C<Sys::Syslog> and selected by default, the use of the C<setlogsock()> function is discouraged because other mechanisms are less portable across operating systems. Authors of modules and programs that use this function, especially its cargo-cult form C<setlogsock("unix")>, are advised to remove any occurrence of it unless they specifically want to use a given mechanism (like TCP or UDP to connect to a remote host). =back =item B<closelog()> Closes the log file and returns true on success. =back =head1 THE RULES OF SYS::SYSLOG I<The First Rule of Sys::Syslog is:> You do not call C<setlogsock>. I<The Second Rule of Sys::Syslog is:> You B<do not> call C<setlogsock>. I<The Third Rule of Sys::Syslog is:> The program crashes, C<die>s, calls C<closelog>, the log is over. I<The Fourth Rule of Sys::Syslog is:> One facility, one priority. I<The Fifth Rule of Sys::Syslog is:> One log at a time. I<The Sixth Rule of Sys::Syslog is:> No C<syslog> before C<openlog>. I<The Seventh Rule of Sys::Syslog is:> Logs will go on as long as they have to. I<The Eighth, and Final Rule of Sys::Syslog is:> If this is your first use of Sys::Syslog, you must read the doc. =head1 EXAMPLES An example: openlog($program, 'cons,pid', 'user'); syslog('info', '%s', 'this is another test'); syslog('mail|warning', 'this is a better test: %d', time); closelog(); syslog('debug', 'this is the last test'); Another example: openlog("$program $$", 'ndelay', 'user'); syslog('notice', 'fooprogram: this is really done'); Example of use of C<%m>: $! = 55; syslog('info', 'problem was %m'); # %m == $! in syslog(3) Log to UDP port on C<$remotehost> instead of logging locally: setlogsock("udp", $remotehost); openlog($program, 'ndelay', 'user'); syslog('info', 'something happened over here'); =head1 CONSTANTS =head2 Facilities =over 4 =item * C<LOG_AUDIT> - audit daemon (IRIX); falls back to C<LOG_AUTH> =item * C<LOG_AUTH> - security/authorization messages =item * C<LOG_AUTHPRIV> - security/authorization messages (private) =item * C<LOG_CONSOLE> - C</dev/console> output (FreeBSD); falls back to C<LOG_USER> =item * C<LOG_CRON> - clock daemons (B<cron> and B<at>) =item * C<LOG_DAEMON> - system daemons without separate facility value =item * C<LOG_FTP> - FTP daemon =item * C<LOG_KERN> - kernel messages =item * C<LOG_INSTALL> - installer subsystem (Mac OS X); falls back to C<LOG_USER> =item * C<LOG_LAUNCHD> - launchd - general bootstrap daemon (Mac OS X); falls back to C<LOG_DAEMON> =item * C<LOG_LFMT> - logalert facility; falls back to C<LOG_USER> =item * C<LOG_LOCAL0> through C<LOG_LOCAL7> - reserved for local use =item * C<LOG_LPR> - line printer subsystem =item * C<LOG_MAIL> - mail subsystem =item * C<LOG_NETINFO> - NetInfo subsystem (Mac OS X); falls back to C<LOG_DAEMON> =item * C<LOG_NEWS> - USENET news subsystem =item * C<LOG_NTP> - NTP subsystem (FreeBSD, NetBSD); falls back to C<LOG_DAEMON> =item * C<LOG_RAS> - Remote Access Service (VPN / PPP) (Mac OS X); falls back to C<LOG_AUTH> =item * C<LOG_REMOTEAUTH> - remote authentication/authorization (Mac OS X); falls back to C<LOG_AUTH> =item * C<LOG_SECURITY> - security subsystems (firewalling, etc.) (FreeBSD); falls back to C<LOG_AUTH> =item * C<LOG_SYSLOG> - messages generated internally by B<syslogd> =item * C<LOG_USER> (default) - generic user-level messages =item * C<LOG_UUCP> - UUCP subsystem =back =head2 Levels =over 4 =item * C<LOG_EMERG> - system is unusable =item * C<LOG_ALERT> - action must be taken immediately =item * C<LOG_CRIT> - critical conditions =item * C<LOG_ERR> - error conditions =item * C<LOG_WARNING> - warning conditions =item * C<LOG_NOTICE> - normal, but significant, condition =item * C<LOG_INFO> - informational message =item * C<LOG_DEBUG> - debug-level message =back =head1 DIAGNOSTICS =over =item C<Invalid argument passed to setlogsock> B<(F)> You gave C<setlogsock()> an invalid value for C<$sock_type>. =item C<eventlog passed to setlogsock, but no Win32 API available> B<(W)> You asked C<setlogsock()> to use the Win32 event logger but the operating system running the program isn't Win32 or does not provides Win32 compatible facilities. =item C<no connection to syslog available> B<(F)> C<syslog()> failed to connect to the specified socket. =item C<stream passed to setlogsock, but %s is not writable> B<(W)> You asked C<setlogsock()> to use a stream socket, but the given path is not writable. =item C<stream passed to setlogsock, but could not find any device> B<(W)> You asked C<setlogsock()> to use a stream socket, but didn't provide a path, and C<Sys::Syslog> was unable to find an appropriate one. =item C<tcp passed to setlogsock, but tcp service unavailable> B<(W)> You asked C<setlogsock()> to use a TCP socket, but the service is not available on the system. =item C<syslog: expecting argument %s> B<(F)> You forgot to give C<syslog()> the indicated argument. =item C<syslog: invalid level/facility: %s> B<(F)> You specified an invalid level or facility. =item C<syslog: too many levels given: %s> B<(F)> You specified too many levels. =item C<syslog: too many facilities given: %s> B<(F)> You specified too many facilities. =item C<syslog: level must be given> B<(F)> You forgot to specify a level. =item C<udp passed to setlogsock, but udp service unavailable> B<(W)> You asked C<setlogsock()> to use a UDP socket, but the service is not available on the system. =item C<unix passed to setlogsock, but path not available> B<(W)> You asked C<setlogsock()> to use a UNIX socket, but C<Sys::Syslog> was unable to find an appropriate an appropriate device. =back =head1 HISTORY C<Sys::Syslog> is a core module, part of the standard Perl distribution since 1990. At this time, modules as we know them didn't exist, the Perl library was a collection of F<.pl> files, and the one for sending syslog messages with was simply F<lib/syslog.pl>, included with Perl 3.0. It was converted as a module with Perl 5.0, but had a version number only starting with Perl 5.6. Here is a small table with the matching Perl and C<Sys::Syslog> versions. Sys::Syslog Perl ----------- ---- undef 5.0.0 ~ 5.5.4 0.01 5.6.* 0.03 5.8.0 0.04 5.8.1, 5.8.2, 5.8.3 0.05 5.8.4, 5.8.5, 5.8.6 0.06 5.8.7 0.13 5.8.8 0.22 5.10.0 0.27 5.8.9, 5.10.1 ~ 5.14.* 0.29 5.16.* 0.32 5.18.* 0.33 5.20.* 0.33 5.22.* =head1 SEE ALSO =head2 Other modules L<Log::Log4perl> - Perl implementation of the Log4j API L<Log::Dispatch> - Dispatches messages to one or more outputs L<Log::Report> - Report a problem, with exceptions and language support =head2 Manual Pages L<syslog(3)> SUSv3 issue 6, IEEE Std 1003.1, 2004 edition, L<http://www.opengroup.org/onlinepubs/000095399/basedefs/syslog.h.html> GNU C Library documentation on syslog, L<http://www.gnu.org/software/libc/manual/html_node/Syslog.html> FreeBSD documentation on syslog, L<https://www.freebsd.org/cgi/man.cgi?query=syslog> Solaris 11 documentation on syslog, L<https://docs.oracle.com/cd/E53394_01/html/E54766/syslog-3c.html> Mac OS X documentation on syslog, L<http://developer.apple.com/documentation/Darwin/Reference/ManPages/man3/syslog.3.html> IRIX documentation on syslog, L<http://nixdoc.net/man-pages/IRIX/man3/syslog.3c.html> AIX 5L 5.3 documentation on syslog, L<http://publib.boulder.ibm.com/infocenter/pseries/v5r3/index.jsp?topic=/com.ibm.aix.basetechref/doc/basetrf2/syslog.htm> HP-UX 11i documentation on syslog, L<http://docs.hp.com/en/B2355-60130/syslog.3C.html> Tru64 documentation on syslog, L<http://nixdoc.net/man-pages/Tru64/man3/syslog.3.html> Stratus VOS 15.1, L<http://stratadoc.stratus.com/vos/15.1.1/r502-01/wwhelp/wwhimpl/js/html/wwhelp.htm?context=r502-01&file=ch5r502-01bi.html> =head2 RFCs I<RFC 3164 - The BSD syslog Protocol>, L<http://www.faqs.org/rfcs/rfc3164.html> -- Please note that this is an informational RFC, and therefore does not specify a standard of any kind. I<RFC 3195 - Reliable Delivery for syslog>, L<http://www.faqs.org/rfcs/rfc3195.html> =head2 Articles I<Syslogging with Perl>, L<http://lexington.pm.org/meetings/022001.html> =head2 Event Log Windows Event Log, L<http://msdn.microsoft.com/library/default.asp?url=/library/en-us/wes/wes/windows_event_log.asp> =head1 AUTHORS & ACKNOWLEDGEMENTS Tom Christiansen E<lt>F<tchrist (at) perl.com>E<gt> and Larry Wall E<lt>F<larry (at) wall.org>E<gt>. UNIX domain sockets added by Sean Robinson E<lt>F<robinson_s (at) sc.maricopa.edu>E<gt> with support from Tim Bunce E<lt>F<Tim.Bunce (at) ig.co.uk>E<gt> and the C<perl5-porters> mailing list. Dependency on F<syslog.ph> replaced with XS code by Tom Hughes E<lt>F<tom (at) compton.nu>E<gt>. Code for C<constant()>s regenerated by Nicholas Clark E<lt>F<nick (at) ccl4.org>E<gt>. Failover to different communication modes by Nick Williams E<lt>F<Nick.Williams (at) morganstanley.com>E<gt>. Extracted from core distribution for publishing on the CPAN by SE<eacute>bastien Aperghis-Tramoni E<lt>sebastien (at) aperghis.netE<gt>. XS code for using native C functions borrowed from C<L<Unix::Syslog>>, written by Marcus Harnisch E<lt>F<marcus.harnisch (at) gmx.net>E<gt>. Yves Orton suggested and helped for making C<Sys::Syslog> use the native event logger under Win32 systems. Jerry D. Hedden and Reini Urban provided greatly appreciated help to debug and polish C<Sys::Syslog> under Cygwin. =head1 BUGS Please report any bugs or feature requests to C<bug-sys-syslog (at) rt.cpan.org>, or through the web interface at L<http://rt.cpan.org/Public/Dist/Display.html?Name=Sys-Syslog>. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes. =head1 SUPPORT You can find documentation for this module with the perldoc command. perldoc Sys::Syslog You can also look for information at: =over =item * Perl Documentation L<http://perldoc.perl.org/Sys/Syslog.html> =item * MetaCPAN L<https://metacpan.org/module/Sys::Syslog> =item * Search CPAN L<http://search.cpan.org/dist/Sys-Syslog/> =item * AnnoCPAN: Annotated CPAN documentation L<http://annocpan.org/dist/Sys-Syslog> =item * CPAN Ratings L<http://cpanratings.perl.org/d/Sys-Syslog> =item * RT: CPAN's request tracker L<http://rt.cpan.org/Dist/Display.html?Queue=Sys-Syslog> =back The source code is available on Git Hub: L<https://github.com/maddingue/Sys-Syslog/> =head1 COPYRIGHT Copyright (C) 1990-2012 by Larry Wall and others. =head1 LICENSE This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself. =cut =begin comment Notes for the future maintainer (even if it's still me..) - - - - - - - - - - - - - - - - - - - - - - - - - - - - - Using Google Code Search, I search who on Earth was relying on $host being public. It found 5 hits: * First was inside Indigo Star Perl2exe documentation. Just an old version of Sys::Syslog. * One real hit was inside DalWeathDB, a weather related program. It simply does a $Sys::Syslog::host = '127.0.0.1'; - L<http://www.gallistel.net/nparker/weather/code/> * Two hits were in TPC, a fax server thingy. It does a $Sys::Syslog::host = $TPC::LOGHOST; but also has this strange piece of code: # work around perl5.003 bug sub Sys::Syslog::hostname {} I don't know what bug the author referred to. - L<http://www.tpc.int/> - L<ftp://ftp-usa.tpc.int/pub/tpc/server/UNIX/> * Last hit was in Filefix, which seems to be a FIDOnet mail program (!). This one does not use $host, but has the following piece of code: sub Sys::Syslog::hostname { use Sys::Hostname; return hostname; } I guess this was a more elaborate form of the previous bit, maybe because of a bug in Sys::Syslog back then? - L<ftp://ftp.kiae.su/pub/unix/fido/> Links ----- Linux Fast-STREAMS - L<http://www.openss7.org/streams.html> II12021: SYSLOGD HOWTO TCPIPINFO (z/OS, OS/390, MVS) - L<http://www-1.ibm.com/support/docview.wss?uid=isg1II12021> Getting the most out of the Event Viewer - L<http://www.codeproject.com/dotnet/evtvwr.asp?print=true> Log events to the Windows NT Event Log with JNI - L<http://www.javaworld.com/javaworld/jw-09-2001/jw-0928-ntmessages.html> =end comment