#!/usr/bin/perl
# The LearningOnline Network
# lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
#
# $Id: lonsql,v 1.47 2002/06/18 19:39:13 www Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
#
# LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
# YEAR=2000
# lonsql-based on the preforker:harsha jagasia:date:5/10/00
# 7/25 Gerd Kortemeyer
# many different dates Scott Harrison
# YEAR=2001
# many different dates Scott Harrison
# 03/22/2001 Scott Harrison
# 8/30 Gerd Kortemeyer
# 10/17,11/28,11/29,12/20 Scott Harrison
# YEAR=2001
# 5/11 Scott Harrison
#
###
###############################################################################
## ##
## ORGANIZATION OF THIS PERL SCRIPT ##
## 1. Modules used ##
## 2. Enable find subroutine ##
## 3. Read httpd config files and get variables ##
## 4. Make sure that database can be accessed ##
## 5. Make sure this process is running from user=www ##
## 6. Check if other instance is running ##
## 7. POD (plain old documentation, CPAN style) ##
## ##
###############################################################################
use lib '/home/httpd/lib/perl/';
use LONCAPA::Configuration;
use IO::Socket;
use Symbol;
use POSIX;
use IO::Select;
use IO::File;
use Socket;
use Fcntl;
use Tie::RefHash;
use DBI;
my @metalist;
# ----------------- Code to enable 'find' subroutine listing of the .meta files
require "find.pl";
sub wanted {
(($dev,$ino,$mode,$nlink,$uid,$gid) = lstat($_)) &&
-f _ &&
/^.*\.meta$/ && !/^.+\.\d+\.[^\.]+\.meta$/ &&
push(@metalist,"$dir/$_");
}
$childmaxattempts=10;
$run =0;#running counter to generate the query-id
# -------------------------------- Read loncapa_apache.conf and loncapa.conf
my $perlvarref=LONCAPA::Configuration::read_conf('loncapa_apache.conf',
'loncapa.conf');
my %perlvar=%{$perlvarref};
# ------------------------------------- Make sure that database can be accessed
{
my $dbh;
unless (
$dbh = DBI->connect("DBI:mysql:loncapa","www",$perlvar{'lonSqlAccess'},{ RaiseError =>0,PrintError=>0})
) {
print "Cannot connect to database!\n";
$emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
$subj="LON: $perlvar{'lonHostID'} Cannot connect to database!";
system("echo 'Cannot connect to MySQL database!' |\
mailto $emailto -s '$subj' > /dev/null");
exit 1;
}
else {
$dbh->disconnect;
}
}
# --------------------------------------------- Check if other instance running
my $pidfile="$perlvar{'lonDaemons'}/logs/lonsql.pid";
if (-e $pidfile) {
my $lfh=IO::File->new("$pidfile");
my $pide=<$lfh>;
chomp($pide);
if (kill 0 => $pide) { die "already running"; }
}
# ------------------------------------------------------------- Read hosts file
$PREFORK=4; # number of children to maintain, at least four spare
open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
while ($configline=<CONFIG>) {
my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
chomp($ip);
$hostip{$ip}=$id;
if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }
$PREFORK++;
}
close(CONFIG);
$PREFORK=int($PREFORK/4);
$unixsock = "mysqlsock";
my $localfile="$perlvar{'lonSockDir'}/$unixsock";
my $server;
unlink ($localfile);
unless ($server=IO::Socket::UNIX->new(Local =>"$localfile",
Type => SOCK_STREAM,
Listen => 10))
{
print "in socket error:$@\n";
}
# -------------------------------------------------------- Routines for forking
# global variables
$MAX_CLIENTS_PER_CHILD = 5; # number of clients each child should process
%children = (); # keys are current child process IDs
$children = 0; # current number of children
sub REAPER { # takes care of dead children
$SIG{CHLD} = \&REAPER;
my $pid = wait;
$children --;
&logthis("Child $pid died");
delete $children{$pid};
}
sub HUNTSMAN { # signal handler for SIGINT
local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
kill 'INT' => keys %children;
my $execdir=$perlvar{'lonDaemons'};
unlink("$execdir/logs/lonsql.pid");
&logthis("<font color=red>CRITICAL: Shutting down</font>");
$unixsock = "mysqlsock";
my $port="$perlvar{'lonSockDir'}/$unixsock";
unlink(port);
exit; # clean up with dignity
}
sub HUPSMAN { # signal handler for SIGHUP
local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
kill 'INT' => keys %children;
close($server); # free up socket
&logthis("<font color=red>CRITICAL: Restarting</font>");
my $execdir=$perlvar{'lonDaemons'};
$unixsock = "mysqlsock";
my $port="$perlvar{'lonSockDir'}/$unixsock";
unlink(port);
exec("$execdir/lonsql"); # here we go again
}
sub logthis {
my $message=shift;
my $execdir=$perlvar{'lonDaemons'};
my $fh=IO::File->new(">>$execdir/logs/lonsqlfinal.log");
my $now=time;
my $local=localtime($now);
print $fh "$local ($$): $message\n";
}
# ------------------------------------------------------------------ Course log
sub courselog {
my ($path,$command)=@_;
my %filters=();
foreach (split(/\:/,&unescape($command))) {
my ($name,$value)=split(/\=/,$_);
$filters{$name}=$value;
}
my @results=();
open(IN,$path.'/activity.log') or return ('file_error');
while ($line=<IN>) {
chomp($line);
my ($timestamp,$host,$log)=split(/\:/,$line);
foreach (split(/\&/,&unescape($log))) {
my ($time,$res,$uname,$udom,$action,$values)=split(/\:/,$_);
my $include=1;
if (($filters{'username'}) && ($uname ne $filters{'username'}))
{ $include=0; }
if (($filters{'domain'}) && ($udom ne $filters{'domain'}))
{ $include=0; }
if (($filters{'url'}) && ($res!~/$filters{'url'}/))
{ $include=0; }
if (($filters{'start'}) && ($time<$filters{'start'}))
{ $include=0; }
if (($filters{'end'}) && ($time>$filters{'end'}))
{ $include=0; }
if (($filters{'action'} eq 'view') && ($action))
{ $include=0; }
if (($filters{'action'} eq 'submit') && ($action ne 'POST'))
{ $include=0; }
if (($filters{'action'} eq 'grade') && ($action ne 'CSTORE'))
{ $include=0; }
if ($include) {
push(@results,$time.':'.$res.':'.$uname.':'.$udom.':'.
$action.':'.$values);
}
}
}
close IN;
return join('&',sort(@results));
}
# -------------------------------------------------------------------- User log
sub userlog {
my ($path,$command)=@_;
my %filters=();
foreach (split(/\:/,&unescape($command))) {
my ($name,$value)=split(/\=/,$_);
$filters{$name}=$value;
}
my @results=();
open(IN,$path.'/activity.log') or return ('file_error');
while ($line=<IN>) {
chomp($line);
my ($timestamp,$host,$log)=split(/\:/,$line);
$log=&unescape($log);
my $include=1;
if (($filters{'action'} eq 'log') && ($log!~/^Log/)) { $include=0; }
if ($include) {
push(@results,$timestamp.':'.$log);
}
}
close IN;
return join('&',sort(@results));
}
# ---------------------------------------------------- Fork once and dissociate
$fpid=fork;
exit if $fpid;
die "Couldn't fork: $!" unless defined ($fpid);
POSIX::setsid() or die "Can't start new session: $!";
# ------------------------------------------------------- Write our PID on disk
$execdir=$perlvar{'lonDaemons'};
open (PIDSAVE,">$execdir/logs/lonsql.pid");
print PIDSAVE "$$\n";
close(PIDSAVE);
&logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
# ----------------------------- Ignore signals generated during initial startup
$SIG{HUP}=$SIG{USR1}='IGNORE';
# ------------------------------------------------------- Now we are on our own
# Fork off our children.
for (1 .. $PREFORK) {
make_new_child();
}
# Install signal handlers.
$SIG{CHLD} = \&REAPER;
$SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
$SIG{HUP} = \&HUPSMAN;
# And maintain the population.
while (1) {
sleep; # wait for a signal (i.e., child's death)
for ($i = $children; $i < $PREFORK; $i++) {
make_new_child(); # top up the child pool
}
}
sub make_new_child {
my $pid;
my $sigset;
# block signal for fork
$sigset = POSIX::SigSet->new(SIGINT);
sigprocmask(SIG_BLOCK, $sigset)
or die "Can't block SIGINT for fork: $!\n";
die "fork: $!" unless defined ($pid = fork);
if ($pid) {
# Parent records the child's birth and returns.
sigprocmask(SIG_UNBLOCK, $sigset)
or die "Can't unblock SIGINT for fork: $!\n";
$children{$pid} = 1;
$children++;
return;
} else {
# Child can *not* return from this subroutine.
$SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
# unblock signals
sigprocmask(SIG_UNBLOCK, $sigset)
or die "Can't unblock SIGINT for fork: $!\n";
#open database handle
# making dbh global to avoid garbage collector
unless (
$dbh = DBI->connect("DBI:mysql:loncapa","www",$perlvar{'lonSqlAccess'},{ RaiseError =>0,PrintError=>0})
) {
sleep(10+int(rand(20)));
&logthis("<font color=blue>WARNING: Couldn't connect to database ($st secs): $@</font>");
print "database handle error\n";
exit;
};
# make sure that a database disconnection occurs with ending kill signals
$SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
# handle connections until we've reached $MAX_CLIENTS_PER_CHILD
for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
$client = $server->accept() or last;
# do something with the connection
$run = $run+1;
my $userinput = <$client>;
chomp($userinput);
my ($conserver,$query,
$arg1,$arg2,$arg3)=split(/&/,$userinput);
my $query=unescape($query);
#send query id which is pid_unixdatetime_runningcounter
$queryid = $thisserver;
$queryid .="_".($$)."_";
$queryid .= time."_";
$queryid .= $run;
print $client "$queryid\n";
&logthis("QUERY: $query - $arg1 - $arg2 - $arg3");
sleep 1;
my $result='';
# ---------- At this point, query is received, query-ID assigned and sent back
# $query eq 'logquery' will mean that this is a query against log-files
if (($query eq 'userlog') || ($query eq 'courselog')) {
# ----------------------------------------------------- beginning of log query
#
# this goes against a user's log file
#
my $udom=&unescape($arg1);
my $uname=&unescape($arg2);
my $command=&unescape($arg3);
my $path=&propath($udom,$uname);
if (-e "$path/activity.log") {
if ($query eq 'userlog') {
$result=&userlog($path,$command);
} else {
$result=&courselog($path,$command);
}
} else {
&logthis('Unable to do log query: '.$uname.'@'.$udom);
$result='no_such_file';
}
# ------------------------------------------------------------ end of log query
} else {
# -------------------------------------------------------- This is an sql query
my $custom=unescape($arg1);
my $customshow=unescape($arg2);
#prepare and execute the query
my $sth = $dbh->prepare($query);
my @files;
my $subsetflag=0;
if ($query) {
unless ($sth->execute())
{
&logthis("<font color=blue>WARNING: Could not retrieve from database: $@</font>");
$result="";
}
else {
my $r1=$sth->fetchall_arrayref;
my @r2;
foreach (@$r1) {my $a=$_;
my @b=map {escape($_)} @$a;
push @files,@{$a}[3];
push @r2,join(",", @b)
}
$result=join("&",@r2);
}
}
# do custom metadata searching here and build into result
if ($custom or $customshow) {
&logthis("am going to do custom query for $custom");
if ($query) {
@metalist=map {$perlvar{'lonDocRoot'}.$_.'.meta'} @files;
}
else {
@metalist=(); pop @metalist;
opendir(RESOURCES,"$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}");
my @homeusers=grep
{&ishome("$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}/$_")}
grep {!/^\.\.?$/} readdir(RESOURCES);
closedir RESOURCES;
foreach my $user (@homeusers) {
&find("$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}/$user");
}
}
# &logthis("FILELIST:" . join(":::",@metalist));
# if file is indicated in sql database and
# not part of sql-relevant query, do not pattern match.
# if file is not in sql database, output error.
# if file is indicated in sql database and is
# part of query result list, then do the pattern match.
my $customresult='';
my @r2;
foreach my $m (@metalist) {
my $fh=IO::File->new($m);
my @lines=<$fh>;
my $stuff=join('',@lines);
if ($stuff=~/$custom/s) {
foreach my $f ('abstract','author','copyright',
'creationdate','keywords','language',
'lastrevisiondate','mime','notes',
'owner','subject','title') {
$stuff=~s/\n?\<$f[^\>]*\>.*?<\/$f[^\>]*\>\n?//s;
}
my $m2=$m; my $docroot=$perlvar{'lonDocRoot'};
$m2=~s/^$docroot//;
$m2=~s/\.meta$//;
unless ($query) {
my $q2="select * from metadata where url like binary '$m2'";
my $sth = $dbh->prepare($q2);
$sth->execute();
my $r1=$sth->fetchall_arrayref;
foreach (@$r1) {my $a=$_;
my @b=map {escape($_)} @$a;
push @files,@{$a}[3];
push @r2,join(",", @b)
}
}
# &logthis("found: $stuff");
$customresult.='&custom='.escape($m2).','.escape($stuff);
}
}
$result=join("&",@r2) unless $query;
$result.=$customresult;
}
# ------------------------------------------------------------ end of sql query
}
# result does need to be escaped
$result=&escape($result);
# reply with result, append \n unless already there
$result.="\n" unless ($result=~/\n$/);
&reply("queryreply:$queryid:$result",$conserver);
}
# tidy up gracefully and finish
#close the database handle
$dbh->disconnect
or &logthis("<font color=blue>WARNING: Couldn't disconnect from database $DBI::errstr ($st secs): $@</font>");
# this exit is VERY important, otherwise the child will become
# a producer of more and more children, forking yourself into
# process death.
exit;
}
}
sub DISCONNECT {
$dbh->disconnect or
&logthis("<font color=blue>WARNING: Couldn't disconnect from database $DBI::errstr ($st secs): $@</font>");
exit;
}
# -------------------------------------------------- Non-critical communication
sub subreply {
my ($cmd,$server)=@_;
my $peerfile="$perlvar{'lonSockDir'}/$server";
my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
Type => SOCK_STREAM,
Timeout => 10)
or return "con_lost";
print $sclient "$cmd\n";
my $answer=<$sclient>;
chomp($answer);
if (!$answer) { $answer="con_lost"; }
return $answer;
}
sub reply {
my ($cmd,$server)=@_;
my $answer;
if ($server ne $perlvar{'lonHostID'}) {
$answer=subreply($cmd,$server);
if ($answer eq 'con_lost') {
$answer=subreply("ping",$server);
$answer=subreply($cmd,$server);
}
} else {
$answer='self_reply';
$answer=subreply($cmd,$server);
}
return $answer;
}
# -------------------------------------------------------- Escape Special Chars
sub escape {
my $str=shift;
$str =~ s/(\W)/"%".unpack('H2',$1)/eg;
return $str;
}
# ----------------------------------------------------- Un-Escape Special Chars
sub unescape {
my $str=shift;
$str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
return $str;
}
# --------------------------------------- Is this the home server of an author?
# (copied from lond, modification of the return value)
sub ishome {
my $author=shift;
$author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
my ($udom,$uname)=split(/\//,$author);
my $proname=propath($udom,$uname);
if (-e $proname) {
return 1;
} else {
return 0;
}
}
# -------------------------------------------- Return path to profile directory
# (copied from lond)
sub propath {
my ($udom,$uname)=@_;
$udom=~s/\W//g;
$uname=~s/\W//g;
my $subdir=$uname.'__';
$subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
return $proname;
}
# ----------------------------------- POD (plain old documentation, CPAN style)
=head1 NAME
lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
=head1 SYNOPSIS
This script should be run as user=www. The following is an example invocation
from the loncron script. Note that a lonsql.pid file contains the pid of
the parent process.
if (-e $lonsqlfile) {
my $lfh=IO::File->new("$lonsqlfile");
my $lonsqlpid=<$lfh>;
chomp($lonsqlpid);
if (kill 0 => $lonsqlpid) {
print $fh "<h3>lonsql at pid $lonsqlpid responding</h3>";
$restartflag=0;
} else {
$errors++; $errors++;
print $fh "<h3>lonsql at pid $lonsqlpid not responding</h3>";
$restartflag=1;
print $fh
"<h3>Decided to clean up stale .pid file and restart lonsql</h3>";
}
}
if ($restartflag==1) {
$errors++;
print $fh '<br><font color="red">Killall lonsql: '.
system('killall lonsql').' - ';
sleep 60;
print $fh unlink($lonsqlfile).' - '.
system('killall -9 lonsql').
'</font><br>';
print $fh "<h3>lonsql not running, trying to start</h3>";
system(
"$perlvar{'lonDaemons'}/lonsql 2>>$perlvar{'lonDaemons'}/logs/lonsql_errors");
sleep 10;
=head1 DESCRIPTION
Not yet written.
=head1 README
Not yet written.
=head1 PREREQUISITES
IO::Socket
Symbol
POSIX
IO::Select
IO::File
Socket
Fcntl
Tie::RefHash
DBI
=head1 COREQUISITES
=head1 OSNAMES
linux
=head1 SCRIPT CATEGORIES
Server/Process
=cut
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