Use rsyslog to trigger log rotation

The previous implementation of log rotation used an hourly cron job to
check log file size and possibly perform a rotation. If the logging
rate is high, this interval may allow for root file system space
exhustion.

Utilizing rsyslog's outchannel mechanism enables log rotation to be
initiated as soon as the log file becomes larger than its configured
size.

Fixes Bug 7807.

2 files changed, 81 insertions, 25 deletions

diff --git a/scripts/system/vyatta_update_logrotate.pl b/scripts/system/vyatta_update_logrotate.pl
index a3a879ba..05867658 100755
--- a/scripts/system/vyatta_update_logrotate.pl
+++ b/scripts/system/vyatta_update_logrotate.pl
@@ -1,17 +1,25 @@
 #!/usr/bin/perl
 
+# Exit code:
+#   0 - success
+#   1 - missing parameter
+#   2 - invalid files or size parameters
+#   3 - unable to write logrotate config
+
 use strict;
 
-my $file = "messages";
+my $cfg_dir = "/opt/vyatta/etc/logrotate";
+my $file = "global";
 my $log_file = "/var/log/messages";
+my $log_conf = "${cfg_dir}/$file";
 if ($#ARGV == 3) {
   $file = shift;
   $log_file = "/var/log/user/$file";
+  $log_conf = "${cfg_dir}/file_$file";
 }
 my $files = shift;
 my $size = shift;
 my $set = shift;
-my $log_conf = "/etc/logrotate.d/$file";
 
 if (!defined($files) || !defined($size) || !defined($set)) {
   exit 1;
@@ -25,7 +33,7 @@ if (!($files =~ m/^\d+$/) || !($size =~ m/^\d+$/)) {
 # (the detection mechanism in XORP doesn't work anyway)
 unlink $log_conf;
 
-open my $out, '>>', $log_conf
+open my $out, '>', $log_conf
     or exit 3;
 if ($set == 1) {
   print $out <<EOF;
@@ -34,13 +42,9 @@ $log_file {
   notifempty
   rotate $files
   size=${size}k
-  postrotate
-  	invoke-rc.d rsyslog reload >/dev/null
-  endscript
 }
 EOF
 }
 close $out;
 
-exec '/usr/sbin/invoke-rc.d', 'rsyslog', 'restart';
-exit 4;
+exit 0;
diff --git a/scripts/system/vyatta_update_syslog.pl b/scripts/system/vyatta_update_syslog.pl
index 1c4c6d46..3421d61a 100755
--- a/scripts/system/vyatta_update_syslog.pl
+++ b/scripts/system/vyatta_update_syslog.pl
@@ -23,22 +23,42 @@
 use strict;
 use lib "/opt/vyatta/share/perl5";
 use Vyatta::Config;
+use File::Basename;
 use File::Compare;
+use File::Temp qw/ tempfile /;
 
 my $SYSLOG_CONF  = '/etc/rsyslog.d/vyatta-log.conf';
-my $SYSLOG_TMP   = "/tmp/rsyslog.conf.$$";
-my $MESSAGES     = '-/var/log/messages';
+my $SYSLOG_TMPL  = "/tmp/rsyslog.conf.XXXXXX";
+my $MESSAGES     = '/var/log/messages';
 my $CONSOLE      = '/dev/console';
+my $LOGROTATE_CFG_DIR = '/opt/vyatta/etc/logrotate';
 
 my %entries = ();
 
 die "$0 expects no arguments\n" if (@ARGV);
 
-sub add_entry {
+sub add_target_selector {
     my ( $selector, $target ) = @_;
 
-    $entries{$target} = [] unless $entries{$target};
-    push @{ $entries{$target} }, $selector;
+    $entries{$target}{selector} = [] unless $entries{$target}{selector};
+    push @{ $entries{$target}{selector} }, $selector;
+}
+
+sub set_target_param {
+    my ( $config, $level, $target, $param ) = @_;
+    my $path = "$level archive $param";
+
+    if (! $config->exists($path)) {
+        my @tmpl = $config->parseTmpl($path);
+        $entries{$target}{$param} = $tmpl[2];
+    } else {
+        $entries{$target}{$param} = $config->returnValue($path);
+    }
+}
+
+sub get_target_param {
+    my ( $target, $param ) = @_;
+    return $entries{$target}{$param};
 }
 
 # This allows overloading local values in CLI
@@ -57,10 +77,25 @@ sub read_config {
         $facility = $facmap{$facility} if ( $facmap{$facility} );
         $loglevel = '*' if ( $loglevel eq 'all' );
 
-        add_entry( $facility . '.' . $loglevel, $target );
+        $entries{$target} = {} unless $entries{$target};
+        add_target_selector( $facility . '.' . $loglevel, $target );
+    }
+
+    # This is a file target so we set size and files
+    if ($target =~ m:^/var/log/:) {
+        set_target_param($config, $level, $target, 'size');
+        set_target_param($config, $level, $target, 'files');
     }
 }
 
+sub print_outchannel {
+    my ( $fh, $channel, $target, $size ) = @_;
+    # Force outchannel size to be 1k more than logrotate config to guarantee rotation
+    $size = ($size + 5) * 1024;
+    print $fh "\$outchannel $channel,$target,$size,/usr/sbin/logrotate ${LOGROTATE_CFG_DIR}/$channel\n";
+    print $fh join( ';', @{ $entries{$target}{selector} } ), " \$$channel\n";
+}
+
 my $config = new Vyatta::Config;
 $config->setLevel("system syslog");
 
@@ -68,8 +103,8 @@ read_config( $config, 'global', $MESSAGES );
 
 # Default syslog.conf if no global entry
 unless (%entries) {
-    add_entry( '*.notice', $MESSAGES );
-    add_entry( 'local7.*', $MESSAGES );
+    add_target_selector( '*.notice', $MESSAGES );
+    add_target_selector( 'local7.*', $MESSAGES );
 }
 
 read_config( $config, 'console', $CONSOLE );
@@ -86,23 +121,40 @@ foreach my $user ( $config->listNodes('user') ) {
     read_config( $config, 'user $user', $user );
 }
 
-open my $out, '>', $SYSLOG_TMP
-  or die "Can't open $SYSLOG_TMP: $!";
+my ($out, $tempname) = tempfile($SYSLOG_TMPL, UNLINK => 1)
+  or die "Can't create temp file: $!";
 
+my $files;
+my $size;
 foreach my $target ( keys %entries ) {
-    print $out join( ';', @{ $entries{$target} } ), "\t$target\n";
+    if ($target eq $MESSAGES) {
+        $size = get_target_param($target, 'size');
+        $files = get_target_param($target, 'files');
+        print_outchannel($out, 'global', $target, $size);
+        system("sudo /opt/vyatta/sbin/vyatta_update_logrotate.pl $files $size 1") == 0
+            or die "Can't genrate global log rotation config: $!";
+    } elsif ($target =~ m:^/var/log/user/:) {
+        my $file = basename($target);
+        $size = get_target_param($target, 'size');
+        $files = get_target_param($target, 'files');
+        print_outchannel($out, 'file_' . $file, $target, $size);
+        system("sudo /opt/vyatta/sbin/vyatta_update_logrotate.pl $file $files $size 1") == 0
+            or die "Can't genrate global log rotation config: $!";
+    } else {
+        print $out join( ';', @{ $entries{$target}{selector} } ), "\t$target\n";
+    }
 }
 close $out
-  or die "Can't output $SYSLOG_TMP: $!";
+  or die "Can't output $tempname: $!";
 
 # Don't need to do anything, save time on boot
-if ( -e $SYSLOG_CONF && compare( $SYSLOG_CONF, $SYSLOG_TMP ) == 0 ) {
-    unlink($SYSLOG_TMP);
+if ( -e $SYSLOG_CONF && compare( $SYSLOG_CONF, $tempname ) == 0 ) {
+    unlink($tempname);
     exit 1;
 }
 
-system("sudo cp $SYSLOG_TMP $SYSLOG_CONF") == 0
-  or die "Can't copy $SYSLOG_TMP to $SYSLOG_CONF";
+system("sudo cp $tempname $SYSLOG_CONF") == 0
+  or die "Can't copy $tempname to $SYSLOG_CONF: $!";
 
-unlink($SYSLOG_TMP);
+unlink($tempname);
 exit 0;