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Diff for /loncom/lonsql between versions 1.1 and 1.61

version 1.1, 2000/05/08 15:14:27 version 1.61, 2004/05/20 14:15:29
Line 1 Line 1
 #!/usr/bin/perl  #!/usr/bin/perl
   
 # The LearningOnline Network  # The LearningOnline Network
 # lonsql  # lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
 # provides unix domain sockets to receive queries from lond and send replies to lonc  #
   # $Id$
   #
   # 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/
 #  #
 # PID in subdir logs/lonc.pid  
 # kill kills  
 # HUP restarts  
 # USR1 tries to open connections again  
   
 # 6/4/99,6/5,6/7,6/8,6/9,6/10,6/11,6/12,7/14,7/19,  
 # 10/8,10/9,10/15,11/18,12/22,  
 # 2/8 Gerd Kortemeyer   
 # based on nonforker from Perl Cookbook  
 # - server who multiplexes without forking  
   
 use POSIX;  =pod
   
   =head1 NAME
   
   lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
   
   =head1 SYNOPSIS
   
   This script should be run as user=www.  
   Note that a lonsql.pid file contains the pid of the parent process.
   
   =head1 OVERVIEW
   
   =head2 Purpose within LON-CAPA
   
   LON-CAPA is meant to distribute A LOT of educational content to A LOT
   of people. It is ineffective to directly rely on contents within the
   ext2 filesystem to be speedily scanned for on-the-fly searches of
   content descriptions. (Simply put, it takes a cumbersome amount of
   time to open, read, analyze, and close thousands of files.)
   
   The solution is to index various data fields that are descriptive of
   the educational resources on a LON-CAPA server machine in a
   database. Descriptive data fields are referred to as "metadata". The
   question then arises as to how this metadata is handled in terms of
   the rest of the LON-CAPA network without burdening client and daemon
   processes.
   
   The obvious solution, using lonc to send a query to a lond process,
   doesn't work so well in general as you can see in the following
   example:
   
       lonc= loncapa client process    A-lonc= a lonc process on Server A
       lond= loncapa daemon process
   
                    database command
       A-lonc  --------TCP/IP----------------> B-lond
   
   The problem emerges that A-lonc and B-lond are kept waiting for the
   MySQL server to "do its stuff", or in other words, perform the
   conceivably sophisticated, data-intensive, time-sucking database
   transaction.  By tying up a lonc and lond process, this significantly
   cripples the capabilities of LON-CAPA servers.
   
   The solution is to offload the work onto another process, and use
   lonc and lond just for requests and notifications of completed
   processing:
   
                   database command
   
     A-lonc  ---------TCP/IP-----------------> B-lond =====> B-lonsql
            <---------------------------------/                |
              "ok, I'll get back to you..."                    |
                                                               |
                                                               /
     A-lond  <-------------------------------  B-lonc   <======
              "Guess what? I have the result!"
   
   Of course, depending on success or failure, the messages may vary, but
   the principle remains the same where a separate pool of children
   processes (lonsql's) handle the MySQL database manipulations.
   
   Thus, lonc and lond spend effectively no time waiting on results from
   the database.
   
   =head1 Internals
   
   =over 4
   
   =cut
   
   use strict;
   
   use lib '/home/httpd/lib/perl/';
   use LONCAPA::Configuration;
   use LONCAPA::lonmetadata();
   
 use IO::Socket;  use IO::Socket;
   use Symbol;
   use POSIX;
 use IO::Select;  use IO::Select;
 use IO::File;  use IO::File;
 use Socket;  use Socket;
 use Fcntl;  use Fcntl;
 use Tie::RefHash;  use Tie::RefHash;
 use Crypt::IDEA;  
 use DBI;  use DBI;
   use File::Find;
   
   ########################################################
   ########################################################
   
 $childmaxattempts=10;  =pod
 $run =0;  
 # ------------------------------------ Read httpd access.conf and get variables  =item Global Variables
   
 open (CONFIG,"/etc/httpd/conf/access.conf") || die "Can't read access.conf";  =over 4
   
 while ($configline=<CONFIG>) {  =item dbh
     if ($configline =~ /PerlSetVar/) {  
  my ($dummy,$varname,$varvalue)=split(/\s+/,$configline);  =back
         chomp($varvalue);  
         $perlvar{$varname}=$varvalue;  =cut
     }  
   ########################################################
   ########################################################
   my $dbh;
   
   ########################################################
   ########################################################
   
   =pod 
   
   =item Variables required for forking
   
   =over 4
   
   =item $MAX_CLIENTS_PER_CHILD
   
   The number of clients each child should process.
   
   =item %children 
   
   The keys to %children  are the current child process IDs
   
   =item $children
   
   The current number of children
   
   =back
   
   =cut 
   
   ########################################################
   ########################################################
   my $MAX_CLIENTS_PER_CHILD  = 5;   # number of clients each child should process
   my %children               = ();  # keys are current child process IDs
   my $children               = 0;   # current number of children
                                  
   ###################################################################
   ###################################################################
   
   =pod
   
   =item Main body of code.
   
   =over 4
   
   =item Read data from loncapa_apache.conf and loncapa.conf.
   
   =item Ensure we can access the database.
   
   =item Determine if there are other instances of lonsql running.
   
   =item Read the hosts file.
   
   =item Create a socket for lonsql.
   
   =item Fork once and dissociate from parent.
   
   =item Write PID to disk.
   
   =item Prefork children and maintain the population of children.
   
   =back
   
   =cut
   
   ###################################################################
   ###################################################################
   my $childmaxattempts=10;
   my $run =0;              # running counter to generate the query-id
   #
   # Read loncapa_apache.conf and loncapa.conf
   #
   my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
   my %perlvar=%{$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";
       my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
       my $subj="LON: $perlvar{'lonHostID'} Cannot connect to database!";
       system("echo 'Cannot connect to MySQL database!' |".
              " mailto $emailto -s '$subj' > /dev/null");
   
       open(SMP,'>/home/httpd/html/lon-status/mysql.txt');
       print SMP 'time='.time.'&mysql=defunct'."\n";
       close(SMP);
   
       exit 1;
   } else {
       $dbh->disconnect;
 }  }
 close(CONFIG);  
   
 # ------------------------------------------------------------- Read hosts file  #
 #$PREFORK=4; # number of children to maintain, at least four spare  # 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
   #
   my %hostip;
   my $thisserver;
   my $PREFORK=4; # number of children to maintain, at least four spare
 open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";  open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
   while (my $configline=<CONFIG>) {
 while ($configline=<CONFIG>) {  
     my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);      my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
     chomp($ip);      chomp($ip);
       $hostip{$ip}=$id;
       $thisserver=$name if ($id eq $perlvar{'lonHostID'});
       $PREFORK++;
   }
   close(CONFIG);
   #
   $PREFORK=int($PREFORK/4);
   
   #
   # Create a socket to talk to lond
   #
   my $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";
   }
   
     #$hostip{$ip}=$id;  #
     $hostip{$id}=$ip;  # Fork once and dissociate
   #
   my $fpid=fork;
   exit if $fpid;
   die "Couldn't fork: $!" unless defined ($fpid);
   POSIX::setsid() or die "Can't start new session: $!";
   
     if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }  #
   # Write our PID on disk
   my $execdir=$perlvar{'lonDaemons'};
   open (PIDSAVE,">$execdir/logs/lonsql.pid");
   print PIDSAVE "$$\n";
   close(PIDSAVE);
   &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
   
     #$PREFORK++;  #
   # 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();
 }  }
 close(CONFIG);  
   
   #
   # Install signal handlers.
   $SIG{CHLD} = \&REAPER;
   $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
   $SIG{HUP}  = \&HUPSMAN;
   
 # -------------------------------------------------------- Routines for forking  #
 # global variables  # And maintain the population.
 #$MAX_CLIENTS_PER_CHILD  = 5;        # number of clients each child should process  while (1) {
 %children               = ();       # keys are current child process IDs      sleep;                          # wait for a signal (i.e., child's death)
 #$children               = 0;        # current number of children      for (my $i = $children; $i < $PREFORK; $i++) {
 %childpid               = ();       # the other way around          make_new_child();           # top up the child pool
       }
   }
   
 %childatt               = ();       # number of attempts to start server  ########################################################
                                     # for ID  ########################################################
   
   =pod
   
 sub REAPER {                        # takes care of dead children  =item &make_new_child
     $SIG{CHLD} = \&REAPER;  
     my $pid = wait;  
   
     #$children --;  Inputs: None
     #&logthis("Child $pid died");  
     #delete $children{$pid};  
       
     my $wasserver=$children{$pid};  
     &logthis("<font color=red>CRITICAL: "  
      ."Child $pid for server $wasserver died ($childatt{$wasserver})</font>");  
     delete $children{$pid};  
     delete $childpid{$wasserver};  
     my $port = "$perlvar{'lonSockDir'}/$wasserver";  
     unlink($port);  
   
   Returns: None
   
 }  =cut
   
 sub HUNTSMAN {                      # signal handler for SIGINT  ########################################################
     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children  ########################################################
     kill 'INT' => keys %children;  sub make_new_child {
     my $execdir=$perlvar{'lonDaemons'};      my $pid;
     unlink("$execdir/logs/lonsql.pid");      my $sigset;
     &logthis("<font color=red>CRITICAL: Shutting down</font>");      #
     exit;                           # clean up with dignity      # 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".
                        ": $@</font>");
                        #  "($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 (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
               my $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
       my $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
                   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 {
                   # Do an sql query
                   $result = &do_sql_query($query,$arg1,$arg2);
               }
               # result does not need to be escaped because it has already been
               # escaped.
               #$result=&escape($result);
               &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 : $@</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 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  =pod
     &logthis("<font color=red>CRITICAL: Restarting</font>");  
     my $execdir=$perlvar{'lonDaemons'};  =item &do_sql_query
     exec("$execdir/lonsql");         # here we go again  
   Runs an sql metadata table query.
   
   Inputs: $query, $custom, $customshow
   
   Returns: A string containing escaped results.
   
   =cut
   
   ########################################################
   ########################################################
   {
       my @metalist;
   
   sub process_file {
       if ( -e $_ &&  # file exists
            -f $_ &&  # and is a normal file
            /\.meta$/ &&  # ends in meta
            ! /^.+\.\d+\.[^\.]+\.meta$/  # is not a previous version
            ) {
           push(@metalist,$File::Find::name);
       }
 }  }
   
   sub do_sql_query {
       my ($query,$custom,$customshow) = @_;
       $custom     = &unescape($custom);
       $customshow = &unescape($customshow);
       #
       @metalist = ();
       #
       my $result = '';
       my @results = ();
       my @files;
       my $subsetflag=0;
       #
       if ($query) {
           #prepare and execute the query
           my $sth = $dbh->prepare($query);
           unless ($sth->execute()) {
               &logthis('<font color="blue">'.
                        'WARNING: Could not retrieve from database:'.
                        $sth->errstr().'</font>');
           } else {
               my $aref=$sth->fetchall_arrayref;
               foreach my $row (@$aref) {
                   push @files,@{$row}[3] if ($custom or $customshow);
                   my @b=map { &escape($_); } @$row;
                   push @results,join(",", @b);
                   # Build up the @files array with the LON-CAPA urls 
                   # of the resources.
               }
           }
       }
       # do custom metadata searching here and build into result
       return join("&",@results) if (! ($custom or $customshow));
       # Only get here if there is a custom query or custom show request
       &logthis("Doing custom query for $custom");
       if ($query) {
           @metalist=map {
               $perlvar{'lonDocRoot'}.$_.'.meta';
           } @files;
       } else {
           my $dir = "$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}";
           @metalist=(); 
           opendir(RESOURCES,$dir);
           my @homeusers=grep {
               &ishome($dir.'/'.$_);
           } grep {!/^\.\.?$/} readdir(RESOURCES);
           closedir RESOURCES;
           # Define the
           foreach my $user (@homeusers) {
               find (\&process_file,$dir.'/'.$user);
           }
       } 
       # 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 @results;
       foreach my $metafile (@metalist) {
           my $fh=IO::File->new($metafile);
           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 $mfile=$metafile; 
               my $docroot=$perlvar{'lonDocRoot'};
               $mfile=~s/^$docroot//;
               $mfile=~s/\.meta$//;
               unless ($query) {
                   my $q2="SELECT * FROM metadata WHERE url ".
                       " LIKE BINARY '?'";
                   my $sth = $dbh->prepare($q2);
                   $sth->execute($mfile);
                   my $aref=$sth->fetchall_arrayref;
                   foreach my $a (@$aref) {
                       my @b=map { &escape($_)} @$a;
                       push @results,join(",", @b);
                   }
               }
               # &logthis("found: $stuff");
               $customresult.='&custom='.&escape($mfile).','.
                   escape($stuff);
           }
       }
       $result=join("&",@results) unless $query;
       $result.=$customresult;
       #
       return $result;
   } # End of &do_sql_query
   
   } # End of scoping curly braces for &process_file and &do_sql_query
   ########################################################
   ########################################################
   
   =pod
   
   =item &logthis
   
   Inputs: $message, the message to log
   
   Returns: nothing
   
   Writes $message to the logfile.
   
   =cut
   
   ########################################################
   ########################################################
 sub logthis {  sub logthis {
     my $message=shift;      my $message=shift;
     my $execdir=$perlvar{'lonDaemons'};      my $execdir=$perlvar{'lonDaemons'};
Line 117  sub logthis { Line 582  sub logthis {
     print $fh "$local ($$): $message\n";      print $fh "$local ($$): $message\n";
 }  }
   
 # ----------------------------------------------------------- Send USR1 to lonc  
 sub reconlonc {  
     my $peerfile=shift;  
     &logthis("Trying to reconnect for $peerfile");  
     my $loncfile="$perlvar{'lonDaemons'}/logs/lonc.pid";  
     if (my $fh=IO::File->new("$loncfile")) {  
  my $loncpid=<$fh>;  
         chomp($loncpid);  
         if (kill 0 => $loncpid) {  
     &logthis("lonc at pid $loncpid responding, sending USR1");  
             kill USR1 => $loncpid;  
             sleep 1;  
             if (-e "$peerfile") { return; }  
             &logthis("$peerfile still not there, give it another try");  
             sleep 5;  
             if (-e "$peerfile") { return; }  
             &logthis(  
  "<font color=blue>WARNING: $peerfile still not there, giving up</font>");  
         } else {  
     &logthis(  
               "<font color=red>CRITICAL: "  
              ."lonc at pid $loncpid not responding, giving up</font>");  
         }  
     } else {  
       &logthis('<font color=red>CRITICAL: lonc not running, giving up</font>');  
     }  
 }  
   
 # -------------------------------------------------- Non-critical communication  # -------------------------------------------------- Non-critical communication
   
   ########################################################
   ########################################################
   
   =pod
   
   =item &subreply
   
   Sends a command to a server.  Called only by &reply.
   
   Inputs: $cmd,$server
   
   Returns: The results of the message or 'con_lost' on error.
   
   =cut
   
   ########################################################
   ########################################################
 sub subreply {  sub subreply {
     my ($cmd,$server)=@_;      my ($cmd,$server)=@_;
     my $peerfile="$perlvar{'lonSockDir'}/$server";      my $peerfile="$perlvar{'lonSockDir'}/$server";
Line 156  sub subreply { Line 611  sub subreply {
     print $sclient "$cmd\n";      print $sclient "$cmd\n";
     my $answer=<$sclient>;      my $answer=<$sclient>;
     chomp($answer);      chomp($answer);
     if (!$answer) { $answer="con_lost"; }      $answer="con_lost" if (!$answer);
     return $answer;      return $answer;
 }  }
   
   ########################################################
   ########################################################
   
   =pod
   
   =item &reply
   
   Sends a command to a server.
   
   Inputs: $cmd,$server
   
   Returns: The results of the message or 'con_lost' on error.
   
   =cut
   
   ########################################################
   ########################################################
 sub reply {  sub reply {
   my ($cmd,$server)=@_;    my ($cmd,$server)=@_;
   my $answer;    my $answer;
Line 167  sub reply { Line 639  sub reply {
     $answer=subreply($cmd,$server);      $answer=subreply($cmd,$server);
     if ($answer eq 'con_lost') {      if ($answer eq 'con_lost') {
  $answer=subreply("ping",$server);   $answer=subreply("ping",$server);
         if ($answer ne $server) {  
            &reconlonc("$perlvar{'lonSockDir'}/$server");  
         }  
         $answer=subreply($cmd,$server);          $answer=subreply($cmd,$server);
     }      }
   } else {    } else {
     $answer='self_reply';      $answer='self_reply';
       $answer=subreply($cmd,$server);
   }     } 
   return $answer;    return $answer;
 }  }
   
 $unixsock = "msua1_sql";  ########################################################
 my $localfile="$perlvar{'lonSockDir'}/$unixsock";  ########################################################
 my $server=IO::Socket::UNIX->new(LocalAddr    =>"$localfile",  
   Type    => SOCK_STREAM,  
   Timeout => 10);  
   
 # ---------------------------------------------------- Fork once and dissociate  =pod
 $fpid=fork;  
 exit if $fpid;  
 die "Couldn't fork: $!" unless defined ($fpid);  
   
 POSIX::setsid() or die "Can't start new session: $!";  =item &escape
   
 # ------------------------------------------------------- Write our PID on disk  Escape special characters in a string.
   
 $execdir=$perlvar{'lonDaemons'};  Inputs: string to escape
 open (PIDSAVE,">$execdir/logs/lonsql.pid");  
 print PIDSAVE "$$\n";  
 close(PIDSAVE);  
 &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");  
   
 # ----------------------------- Ignore signals generated during initial startup  Returns: The input string with special characters escaped.
 $SIG{HUP}=$SIG{USR1}='IGNORE';  
   =cut
   
   ########################################################
   ########################################################
   sub escape {
       my $str=shift;
       $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
       return $str;
   }
   
   ########################################################
   ########################################################
   
   =pod
   
 # ------------------------------------------------------- Now we are on our own  =item &unescape
 #Fork of children one for every server  
   
 #for (1 .. $PREFORK) {  Unescape special characters in a string.
 #    make_new_child($thisserver);  
 #}  
   
 foreach $thisserver (keys %hostip) {   Inputs: string to unescape
     make_new_child($thisserver);  
   Returns: The input string with special characters unescaped.
   
   =cut
   
   ########################################################
   ########################################################
   sub unescape {
       my $str=shift;
       $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
       return $str;
 }  }
   
 &logthis("Done starting initial servers");  ########################################################
 # ----------------------------------------------------- Install signal handlers  ########################################################
   
 $SIG{CHLD} = \&REAPER;  =pod
 $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;  
 $SIG{HUP}  = \&HUPSMAN;  
   
 # And maintain the population.  =item &ishome
 while (1) {  
     sleep;                          # wait for a signal (i.e., child's death)  Determine if the current machine is the home server for a user.
   The determination is made by checking the filesystem for the users information.
   
     #for ($i = $children; $i < $PREFORK; $i++) {  Inputs: $author
     #   make_new_child();           # top up the child pool  
     #}  Returns: 0 - this is not the authors home server, 1 - this is.
       
     foreach $thisserver (keys %hostip) {  =cut
         if (!$childpid{$thisserver}) {  
     if ($childatt{$thisserver}<=$childmaxattempts) {  ########################################################
        $childatt{$thisserver}++;  ########################################################
                &logthis(  sub ishome {
    "<font color=yellow>INFO: Trying to reconnect for $thisserver "      my $author=shift;
   ."($childatt{$thisserver} of $childmaxattempts attempts)</font>");       $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
                make_new_child($thisserver);      my ($udom,$uname)=split(/\//,$author);
     }      my $proname=propath($udom,$uname);
         }             if (-e $proname) {
    return 1;
       } else {
           return 0;
     }      }
 }  }
   
 sub make_new_child {  ########################################################
     my $conserver=shift;  ########################################################
     my $pid;  
     my $sigset;  
     my $queryid;  
   
     &logthis("Attempting to start child");      =pod
     # 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);#do the forking of children  
   
     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";  
   
         #connect to the database  =item &propath
  unless (  
  my $dbh = DBI->connect("DBI:mysql:loncapa","root","mysql",{ RaiseError =>1,})  Inputs: user name, user domain
  ) {   
             my $st=120+int(rand(240));  Returns: The full path to the users directory.
     &logthis("<font color=blue>WARNING: Couldn't connect to database  ($st secs): $@</font>");  
     sleep($st);  =cut
     exit;#do I need to cleanup before exit if can't connect to database   
  };  ########################################################
   ########################################################
         # handle connections until we've reached $MAX_CLIENTS_PER_CHILD  sub propath {
         for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {      my ($udom,$uname)=@_;
             $client = $server->accept()     or last;      $udom=~s/\W//g;
     $run = $run+1;      $uname=~s/\W//g;
 # =============================================================================      my $subdir=$uname.'__';
             # do something with the connection      $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
 # -----------------------------------------------------------------------------      my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
     my $userinput = "1";      return $proname;
     #while (my $userinput=<$client>) {  } 
     while (my $userinput="1") {  
     print ("here we go\n");  ########################################################
  chomp($userinput);  ########################################################
     
  #send query id which is pid_unixdatetime_runningcounter  =pod
  $queryid = $conserver;   
  $queryid .=($$)."_";  =item &courselog
  $queryid .= time."_";  
  $queryid .= run;  Inputs: $path, $command
  print $client "$queryid\n";  
   Returns: unescaped string of values.
  #prepare and execute the query  
     =cut
  my $sth = $dbh->prepare("select * into outfile \"$queryid\" from resource");#can't use $userinput directly since we the query to write to a file which depends on the query id generated   
     ########################################################
  $sth->execute();  ########################################################
  if (-e "$queryid") { print "Oops ,file is already there!\n";}  sub courselog {
  else      my ($path,$command)=@_;
  {      my %filters=();
      print "error reading into file\n";      foreach (split(/\:/,&unescape($command))) {
  }   my ($name,$value)=split(/\=/,$_);
             $filters{$name}=$value;
                  #connect to lonc and send the query results      }
  $reply = reply($queryid,$conserver);      my @results=();
         open(IN,$path.'/activity.log') or return ('file_error');
      }      while (my $line=<IN>) {
 # =============================================================================          chomp($line);
           my ($timestamp,$host,$log)=split(/\:/,$line);
   #
   # $log has the actual log entries; currently still escaped, and
   # %26(timestamp)%3a(url)%3a(user)%3a(domain)
   # then additionally
   # %3aPOST%3a(name)%3d(value)%3a(name)%3d(value)
   # or
   # %3aCSTORE%3a(name)%3d(value)%26(name)%3d(value)
   #
   # get delimiter between timestamped entries to be &&&
           $log=~s/\%26(\d+)\%3a/\&\&\&$1\%3a/g;
   # now go over all log entries 
           foreach (split(/\&\&\&/,&unescape($log))) {
       my ($time,$res,$uname,$udom,$action,@values)=split(/\:/,$_);
               my $values=&unescape(join(':',@values));
               $values=~s/\&/\:/g;
               $res=&unescape($res);
               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,($time<1000000000?'0':'').$time.':'.$res.':'.
                                               $uname.':'.$udom.':'.
                                               $action.':'.$values);
               }
          }
       }
       close IN;
       return join('&',sort(@results));
   }
   
   ########################################################
   ########################################################
   
   =pod
   
   =item &userlog
   
   Inputs: $path, $command
   
   Returns: unescaped string of values.
   
   =cut
   
   ########################################################
   ########################################################
   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 (my $line=<IN>) {
           chomp($line);
           my ($timestamp,$host,$log)=split(/\:/,$line);
           $log=&unescape($log);
           my $include=1;
           if (($filters{'start'}) && ($timestamp<$filters{'start'})) 
                                                                { $include=0; }
           if (($filters{'end'}) && ($timestamp>$filters{'end'})) 
                                                                { $include=0; }
           if (($filters{'action'} eq 'log') && ($log!~/^Log/)) { $include=0; }
           if (($filters{'action'} eq 'check') && ($log!~/^Check/)) 
                                                                { $include=0; }
           if ($include) {
      push(@results,$timestamp.':'.$log);
         }          }
       
         # tidy up gracefully and finish  
       
         # this exit is VERY important, otherwise the child will become  
         # a producer of more and more children, forking yourself into  
         # process death.  
         exit;  
     }      }
 }         close IN;
           return join('&',sort(@results));
   }
   
   ########################################################
   ########################################################
   
   =pod
   
       =item Functions required for forking
   
   =over 4
   
   =item REAPER
   
   REAPER takes care of dead children.
   
   =item HUNTSMAN
   
   Signal handler for SIGINT.
   
   =item HUPSMAN
   
   Signal handler for SIGHUP
   
   =item DISCONNECT
   
   Disconnects from database.
   
   =back
   
   =cut
   
   ########################################################
   ########################################################
   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 DISCONNECT {
       $dbh->disconnect or 
       &logthis("<font color='blue'>WARNING: Couldn't disconnect from database ".
                " $DBI::errstr : $@</font>");
       exit;
   }
   
   
   =pod
   
   =back
   
   =cut
Removed from v.1.1  
changed lines
  Added in v.1.61

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