File:  [LON-CAPA] / nsdl / lonsql
Revision 1.1: download - view: text, annotated - select for diffs
Mon Sep 26 19:00:29 2005 UTC (16 years, 10 months ago) by www
Branches: MAIN
CVS tags: HEAD
Work on reverse search with new Cornell search interface

    1: #!/usr/bin/perl
    2: 
    3: # The LearningOnline Network
    4: # lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
    5: #
    6: # $Id: lonsql,v 1.1 2005/09/26 19:00:29 www Exp $
    7: #
    8: # Copyright Michigan State University Board of Trustees
    9: #
   10: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
   11: #
   12: # LON-CAPA is free software; you can redistribute it and/or modify
   13: # it under the terms of the GNU General Public License as published by
   14: # the Free Software Foundation; either version 2 of the License, or
   15: # (at your option) any later version.
   16: #
   17: # LON-CAPA is distributed in the hope that it will be useful,
   18: # but WITHOUT ANY WARRANTY; without even the implied warranty of
   19: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   20: # GNU General Public License for more details.
   21: #
   22: # You should have received a copy of the GNU General Public License
   23: # along with LON-CAPA; if not, write to the Free Software
   24: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   25: #
   26: # /home/httpd/html/adm/gpl.txt
   27: #
   28: # http://www.lon-capa.org/
   29: #
   30: 
   31: =pod
   32: 
   33: =head1 NAME
   34: 
   35: lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
   36: 
   37: =head1 SYNOPSIS
   38: 
   39: This script should be run as user=www.  
   40: Note that a lonsql.pid file contains the pid of the parent process.
   41: 
   42: =head1 OVERVIEW
   43: 
   44: =head2 Purpose within LON-CAPA
   45: 
   46: LON-CAPA is meant to distribute A LOT of educational content to A LOT
   47: of people. It is ineffective to directly rely on contents within the
   48: ext2 filesystem to be speedily scanned for on-the-fly searches of
   49: content descriptions. (Simply put, it takes a cumbersome amount of
   50: time to open, read, analyze, and close thousands of files.)
   51: 
   52: The solution is to index various data fields that are descriptive of
   53: the educational resources on a LON-CAPA server machine in a
   54: database. Descriptive data fields are referred to as "metadata". The
   55: question then arises as to how this metadata is handled in terms of
   56: the rest of the LON-CAPA network without burdening client and daemon
   57: processes.
   58: 
   59: The obvious solution, using lonc to send a query to a lond process,
   60: doesn't work so well in general as you can see in the following
   61: example:
   62: 
   63:     lonc= loncapa client process    A-lonc= a lonc process on Server A
   64:     lond= loncapa daemon process
   65: 
   66:                  database command
   67:     A-lonc  --------TCP/IP----------------> B-lond
   68: 
   69: The problem emerges that A-lonc and B-lond are kept waiting for the
   70: MySQL server to "do its stuff", or in other words, perform the
   71: conceivably sophisticated, data-intensive, time-sucking database
   72: transaction.  By tying up a lonc and lond process, this significantly
   73: cripples the capabilities of LON-CAPA servers.
   74: 
   75: The solution is to offload the work onto another process, and use
   76: lonc and lond just for requests and notifications of completed
   77: processing:
   78: 
   79:                 database command
   80: 
   81:   A-lonc  ---------TCP/IP-----------------> B-lond =====> B-lonsql
   82:          <---------------------------------/                |
   83:            "ok, I'll get back to you..."                    |
   84:                                                             |
   85:                                                             /
   86:   A-lond  <-------------------------------  B-lonc   <======
   87:            "Guess what? I have the result!"
   88: 
   89: Of course, depending on success or failure, the messages may vary, but
   90: the principle remains the same where a separate pool of children
   91: processes (lonsql's) handle the MySQL database manipulations.
   92: 
   93: Thus, lonc and lond spend effectively no time waiting on results from
   94: the database.
   95: 
   96: =head1 Internals
   97: 
   98: =over 4
   99: 
  100: =cut
  101: 
  102: use strict;
  103: 
  104: use lib '/home/httpd/lib/perl/';
  105: use LONCAPA::Configuration;
  106: use LONCAPA::lonmetadata();
  107: 
  108: use IO::Socket;
  109: use Symbol;
  110: use POSIX;
  111: use IO::Select;
  112: use IO::File;
  113: use Socket;
  114: use Fcntl;
  115: use Tie::RefHash;
  116: use DBI;
  117: use File::Find;
  118: use localenroll;
  119: 
  120: ########################################################
  121: ########################################################
  122: 
  123: =pod
  124: 
  125: =item Global Variables
  126: 
  127: =over 4
  128: 
  129: =item dbh
  130: 
  131: =back
  132: 
  133: =cut
  134: 
  135: ########################################################
  136: ########################################################
  137: my $dbh;
  138: 
  139: ########################################################
  140: ########################################################
  141: 
  142: =pod 
  143: 
  144: =item Variables required for forking
  145: 
  146: =over 4
  147: 
  148: =item $MAX_CLIENTS_PER_CHILD
  149: 
  150: The number of clients each child should process.
  151: 
  152: =item %children 
  153: 
  154: The keys to %children  are the current child process IDs
  155: 
  156: =item $children
  157: 
  158: The current number of children
  159: 
  160: =back
  161: 
  162: =cut 
  163: 
  164: ########################################################
  165: ########################################################
  166: my $MAX_CLIENTS_PER_CHILD  = 5;   # number of clients each child should process
  167: my %children               = ();  # keys are current child process IDs
  168: my $children               = 0;   # current number of children
  169:                                
  170: ###################################################################
  171: ###################################################################
  172: 
  173: =pod
  174: 
  175: =item Main body of code.
  176: 
  177: =over 4
  178: 
  179: =item Read data from loncapa_apache.conf and loncapa.conf.
  180: 
  181: =item Ensure we can access the database.
  182: 
  183: =item Determine if there are other instances of lonsql running.
  184: 
  185: =item Read the hosts file.
  186: 
  187: =item Create a socket for lonsql.
  188: 
  189: =item Fork once and dissociate from parent.
  190: 
  191: =item Write PID to disk.
  192: 
  193: =item Prefork children and maintain the population of children.
  194: 
  195: =back
  196: 
  197: =cut
  198: 
  199: ###################################################################
  200: ###################################################################
  201: my $childmaxattempts=10;
  202: my $run =0;              # running counter to generate the query-id
  203: #
  204: # Read loncapa_apache.conf and loncapa.conf
  205: #
  206: my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
  207: my %perlvar=%{$perlvarref};
  208: #
  209: # Write the /home/www/.my.cnf file 
  210: my $conf_file = '/home/www/.my.cnf';
  211: if (! -e $conf_file) {
  212:     if (open MYCNF, ">$conf_file") {
  213:         print MYCNF <<"ENDMYCNF";
  214: [client]
  215: user=www
  216: password=$perlvar{'lonSqlAccess'}
  217: ENDMYCNF
  218:         close MYCNF;
  219:     } else {
  220:         warn "Unable to write $conf_file, continuing";
  221:     }
  222: }
  223: 
  224: 
  225: #
  226: # Make sure that database can be accessed
  227: #
  228: my $dbh;
  229: unless ($dbh = DBI->connect("DBI:mysql:loncapa","www",
  230:                             $perlvar{'lonSqlAccess'},
  231:                             { RaiseError =>0,PrintError=>0})) { 
  232:     print "Cannot connect to database!\n";
  233:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
  234:     my $subj="LON: $perlvar{'lonHostID'} Cannot connect to database!";
  235:     system("echo 'Cannot connect to MySQL database!' |".
  236:            " mailto $emailto -s '$subj' > /dev/null");
  237: 
  238:     open(SMP,'>/home/httpd/html/lon-status/mysql.txt');
  239:     print SMP 'time='.time.'&mysql=defunct'."\n";
  240:     close(SMP);
  241: 
  242:     exit 1;
  243: } else {
  244:     unlink('/home/httpd/html/lon-status/mysql.txt');
  245:     $dbh->disconnect;
  246: }
  247: 
  248: #
  249: # Check if other instance running
  250: #
  251: my $pidfile="$perlvar{'lonDaemons'}/logs/lonsql.pid";
  252: if (-e $pidfile) {
  253:    my $lfh=IO::File->new("$pidfile");
  254:    my $pide=<$lfh>;
  255:    chomp($pide);
  256:    if (kill 0 => $pide) { die "already running"; }
  257: }
  258: 
  259: #
  260: # Read hosts file
  261: #
  262: my $thisserver;
  263: my $PREFORK=4; # number of children to maintain, at least four spare
  264: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
  265: while (my $configline=<CONFIG>) {
  266:     my ($id,$domain,$role,$name)=split(/:/,$configline);
  267:     $name=~s/\s//g;
  268:     $thisserver=$name if ($id eq $perlvar{'lonHostID'});
  269:     #$PREFORK++;
  270: }
  271: close(CONFIG);
  272: #
  273: #$PREFORK=int($PREFORK/4);
  274: 
  275: #
  276: # Create a socket to talk to lond
  277: #
  278: my $unixsock = "mysqlsock";
  279: my $localfile="$perlvar{'lonSockDir'}/$unixsock";
  280: my $server;
  281: unlink ($localfile);
  282: unless ($server=IO::Socket::UNIX->new(Local    =>"$localfile",
  283:                                       Type    => SOCK_STREAM,
  284:                                       Listen => 10)) {
  285:     print "in socket error:$@\n";
  286: }
  287: 
  288: #
  289: # Fork once and dissociate
  290: #
  291: my $fpid=fork;
  292: exit if $fpid;
  293: die "Couldn't fork: $!" unless defined ($fpid);
  294: POSIX::setsid() or die "Can't start new session: $!";
  295: 
  296: #
  297: # Write our PID on disk
  298: my $execdir=$perlvar{'lonDaemons'};
  299: open (PIDSAVE,">$execdir/logs/lonsql.pid");
  300: print PIDSAVE "$$\n";
  301: close(PIDSAVE);
  302: &logthis("<font color='red'>CRITICAL: ---------- Starting ----------</font>");
  303: 
  304: #
  305: # Ignore signals generated during initial startup
  306: $SIG{HUP}=$SIG{USR1}='IGNORE';
  307: # Now we are on our own    
  308: #    Fork off our children.
  309: for (1 .. $PREFORK) {
  310:     make_new_child();
  311: }
  312: 
  313: #
  314: # Install signal handlers.
  315: $SIG{CHLD} = \&REAPER;
  316: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
  317: $SIG{HUP}  = \&HUPSMAN;
  318: 
  319: #
  320: # And maintain the population.
  321: while (1) {
  322:     sleep;                          # wait for a signal (i.e., child's death)
  323:     for (my $i = $children; $i < $PREFORK; $i++) {
  324:         make_new_child();           # top up the child pool
  325:     }
  326: }
  327: 
  328: ########################################################
  329: ########################################################
  330: 
  331: =pod
  332: 
  333: =item &make_new_child
  334: 
  335: Inputs: None
  336: 
  337: Returns: None
  338: 
  339: =cut
  340: 
  341: ########################################################
  342: ########################################################
  343: sub make_new_child {
  344:     my $pid;
  345:     my $sigset;
  346:     #
  347:     # block signal for fork
  348:     $sigset = POSIX::SigSet->new(SIGINT);
  349:     sigprocmask(SIG_BLOCK, $sigset)
  350:         or die "Can't block SIGINT for fork: $!\n";
  351:     #
  352:     die "fork: $!" unless defined ($pid = fork);
  353:     #
  354:     if ($pid) {
  355:         # Parent records the child's birth and returns.
  356:         sigprocmask(SIG_UNBLOCK, $sigset)
  357:             or die "Can't unblock SIGINT for fork: $!\n";
  358:         $children{$pid} = 1;
  359:         $children++;
  360:         return;
  361:     } else {
  362:         # Child can *not* return from this subroutine.
  363:         $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
  364:         # unblock signals
  365:         sigprocmask(SIG_UNBLOCK, $sigset)
  366:             or die "Can't unblock SIGINT for fork: $!\n";
  367:         #open database handle
  368: 	# making dbh global to avoid garbage collector
  369: 	unless ($dbh = DBI->connect("DBI:mysql:loncapa","www",
  370:                                     $perlvar{'lonSqlAccess'},
  371:                                     { RaiseError =>0,PrintError=>0})) { 
  372:             sleep(10+int(rand(20)));
  373:             &logthis("<font color='blue'>WARNING: Couldn't connect to database".
  374:                      ": $@</font>");
  375:                      #  "($st secs): $@</font>");
  376:             print "database handle error\n";
  377:             exit;
  378:         }
  379: 	# make sure that a database disconnection occurs with 
  380:         # ending kill signals
  381: 	$SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
  382:         # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
  383:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
  384:             my $client = $server->accept() or last;
  385:             # do something with the connection
  386: 	    $run = $run+1;
  387: 	    my $userinput = <$client>;
  388: 	    chomp($userinput);
  389:             #
  390: 	    my ($conserver,$query,
  391: 		$arg1,$arg2,$arg3)=split(/&/,$userinput);
  392: 	    my $query=unescape($query);
  393:             #
  394:             #send query id which is pid_unixdatetime_runningcounter
  395: 	    my $queryid = $thisserver;
  396: 	    $queryid .="_".($$)."_";
  397: 	    $queryid .= time."_";
  398: 	    $queryid .= $run;
  399: 	    print $client "$queryid\n";
  400: 	    #
  401: 	    # &logthis("QUERY: $query - $arg1 - $arg2 - $arg3");
  402: 	    sleep 1;
  403:             #
  404:             my $result='';
  405:             #
  406:             # At this point, query is received, query-ID assigned and sent 
  407:             # back, $query eq 'logquery' will mean that this is a query 
  408:             # against log-files
  409:             if (($query eq 'userlog') || ($query eq 'courselog')) {
  410:                 # beginning of log query
  411:                 my $udom    = &unescape($arg1);
  412:                 my $uname   = &unescape($arg2);
  413:                 my $command = &unescape($arg3);
  414:                 my $path    = &propath($udom,$uname);
  415:                 if (-e "$path/activity.log") {
  416:                     if ($query eq 'userlog') {
  417:                         $result=&userlog($path,$command);
  418:                     } else {
  419:                         $result=&courselog($path,$command);
  420:                     }
  421:                 } else {
  422:                     &logthis('Unable to do log query: '.$uname.'@'.$udom);
  423:                     $result='no_such_file';
  424:                 }
  425:                 # end of log query
  426:             } elsif ($query eq 'fetchenrollment') {
  427:                 # retrieve institutional class lists
  428:                 my $dom = &unescape($arg1);
  429:                 my %affiliates = ();
  430:                 my %replies = ();
  431:                 my $locresult = '';
  432:                 my $querystr = &unescape($arg3);
  433:                 foreach (split/%%/,$querystr) {
  434:                     if (/^(\w+)=([^=]+)$/) {
  435:                         @{$affiliates{$1}} = split/,/,$2;
  436:                     }
  437:                 }
  438:                 $locresult = &localenroll::fetch_enrollment($dom,\%affiliates,\%replies);
  439:                 $result = &escape($locresult.':');
  440:                 if ($locresult) {
  441:                     $result .= &escape(join(':',map{$_.'='.$replies{$_}} keys %replies));
  442:                 }
  443:             } elsif ($query eq 'prepare activity log') {
  444:                 my ($cid,$domain) = map {&unescape($_);} ($arg1,$arg2);
  445:                 &logthis('preparing activity log tables for '.$cid);
  446:                 my $command = 
  447:                     qq{$perlvar{'lonDaemons'}/parse_activity_log.pl -course=$cid -domain=$domain};
  448:                 system($command);
  449:                 &logthis($command);
  450:                 my $returnvalue = $?>>8;
  451:                 if ($returnvalue) {
  452:                     $result = 'error: parse_activity_log.pl returned '.
  453:                         $returnvalue;
  454:                 } else {
  455:                     $result = 'success';
  456:                 }
  457:             } else {
  458:                 # Do an sql query
  459:                 $result = &do_sql_query($query,$arg1,$arg2);
  460:             }
  461:             # result does not need to be escaped because it has already been
  462:             # escaped.
  463:             #$result=&escape($result);
  464:             &reply("queryreply:$queryid:$result",$conserver);
  465:         }
  466:         # tidy up gracefully and finish
  467:         #
  468:         # close the database handle
  469: 	$dbh->disconnect
  470:             or &logthis("<font color='blue'>WARNING: Couldn't disconnect".
  471:                         " from database  $DBI::errstr : $@</font>");
  472:         # this exit is VERY important, otherwise the child will become
  473:         # a producer of more and more children, forking yourself into
  474:         # process death.
  475:         exit;
  476:     }
  477: }
  478: 
  479: ########################################################
  480: ########################################################
  481: 
  482: =pod
  483: 
  484: =item &do_sql_query
  485: 
  486: Runs an sql metadata table query.
  487: 
  488: Inputs: $query, $custom, $customshow
  489: 
  490: Returns: A string containing escaped results.
  491: 
  492: =cut
  493: 
  494: ########################################################
  495: ########################################################
  496: {
  497:     my @metalist;
  498: 
  499: sub process_file {
  500:     if ( -e $_ &&  # file exists
  501:          -f $_ &&  # and is a normal file
  502:          /\.meta$/ &&  # ends in meta
  503:          ! /^.+\.\d+\.[^\.]+\.meta$/  # is not a previous version
  504:          ) {
  505:         push(@metalist,$File::Find::name);
  506:     }
  507: }
  508: 
  509: sub do_sql_query {
  510:     my ($query,$custom,$customshow) = @_;
  511:     &logthis('doing query '.$query);
  512:     $custom     = &unescape($custom);
  513:     $customshow = &unescape($customshow);
  514:     #
  515:     @metalist = ();
  516:     #
  517:     my $result = '';
  518:     my @results = ();
  519:     my @files;
  520:     my $subsetflag=0;
  521:     #
  522:     if ($query) {
  523:         #prepare and execute the query
  524:         my $sth = $dbh->prepare($query);
  525:         unless ($sth->execute()) {
  526:             &logthis('<font color="blue">'.
  527:                      'WARNING: Could not retrieve from database:'.
  528:                      $sth->errstr().'</font>');
  529:         } else {
  530:             my $aref=$sth->fetchall_arrayref;
  531:             foreach my $row (@$aref) {
  532:                 push @files,@{$row}[3] if ($custom or $customshow);
  533:                 my @b=map { &escape($_); } @$row;
  534:                 push @results,join(",", @b);
  535:                 # Build up the @files array with the LON-CAPA urls 
  536:                 # of the resources.
  537:             }
  538:         }
  539:     }
  540:     # do custom metadata searching here and build into result
  541:     return join("&",@results) if (! ($custom or $customshow));
  542:     # Only get here if there is a custom query or custom show request
  543:     &logthis("Doing custom query for $custom");
  544:     if ($query) {
  545:         @metalist=map {
  546:             $perlvar{'lonDocRoot'}.$_.'.meta';
  547:         } @files;
  548:     } else {
  549:         my $dir = "$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}";
  550:         @metalist=(); 
  551:         opendir(RESOURCES,$dir);
  552:         my @homeusers=grep {
  553:             &ishome($dir.'/'.$_);
  554:         } grep {!/^\.\.?$/} readdir(RESOURCES);
  555:         closedir RESOURCES;
  556:         # Define the
  557:         foreach my $user (@homeusers) {
  558:             find (\&process_file,$dir.'/'.$user);
  559:         }
  560:     } 
  561:     # if file is indicated in sql database and
  562:     #     not part of sql-relevant query, do not pattern match.
  563:     #
  564:     # if file is not in sql database, output error.
  565:     #
  566:     # if file is indicated in sql database and is
  567:     #     part of query result list, then do the pattern match.
  568:     my $customresult='';
  569:     my @results;
  570:     foreach my $metafile (@metalist) {
  571:         my $fh=IO::File->new($metafile);
  572:         my @lines=<$fh>;
  573:         my $stuff=join('',@lines);
  574:         if ($stuff=~/$custom/s) {
  575:             foreach my $f ('abstract','author','copyright',
  576:                            'creationdate','keywords','language',
  577:                            'lastrevisiondate','mime','notes',
  578:                            'owner','subject','title') {
  579:                 $stuff=~s/\n?\<$f[^\>]*\>.*?<\/$f[^\>]*\>\n?//s;
  580:             }
  581:             my $mfile=$metafile; 
  582:             my $docroot=$perlvar{'lonDocRoot'};
  583:             $mfile=~s/^$docroot//;
  584:             $mfile=~s/\.meta$//;
  585:             unless ($query) {
  586:                 my $q2="SELECT * FROM metadata WHERE url ".
  587:                     " LIKE BINARY '?'";
  588:                 my $sth = $dbh->prepare($q2);
  589:                 $sth->execute($mfile);
  590:                 my $aref=$sth->fetchall_arrayref;
  591:                 foreach my $a (@$aref) {
  592:                     my @b=map { &escape($_)} @$a;
  593:                     push @results,join(",", @b);
  594:                 }
  595:             }
  596:             # &logthis("found: $stuff");
  597:             $customresult.='&custom='.&escape($mfile).','.
  598:                 escape($stuff);
  599:         }
  600:     }
  601:     $result=join("&",@results) unless $query;
  602:     $result.=$customresult;
  603:     #
  604:     return $result;
  605: } # End of &do_sql_query
  606: 
  607: } # End of scoping curly braces for &process_file and &do_sql_query
  608: ########################################################
  609: ########################################################
  610: 
  611: =pod
  612: 
  613: =item &logthis
  614: 
  615: Inputs: $message, the message to log
  616: 
  617: Returns: nothing
  618: 
  619: Writes $message to the logfile.
  620: 
  621: =cut
  622: 
  623: ########################################################
  624: ########################################################
  625: sub logthis {
  626:     my $message=shift;
  627:     my $execdir=$perlvar{'lonDaemons'};
  628:     my $fh=IO::File->new(">>$execdir/logs/lonsql.log");
  629:     my $now=time;
  630:     my $local=localtime($now);
  631:     print $fh "$local ($$): $message\n";
  632: }
  633: 
  634: # -------------------------------------------------- Non-critical communication
  635: 
  636: ########################################################
  637: ########################################################
  638: 
  639: =pod
  640: 
  641: =item &subreply
  642: 
  643: Sends a command to a server.  Called only by &reply.
  644: 
  645: Inputs: $cmd,$server
  646: 
  647: Returns: The results of the message or 'con_lost' on error.
  648: 
  649: =cut
  650: 
  651: ########################################################
  652: ########################################################
  653: sub subreply {
  654:     my ($cmd,$server)=@_;
  655:     my $peerfile="$perlvar{'lonSockDir'}/$server";
  656:     my $sclient=IO::Socket::UNIX->new(Peer    =>"$peerfile",
  657:                                       Type    => SOCK_STREAM,
  658:                                       Timeout => 10)
  659:        or return "con_lost";
  660:     print $sclient "$cmd\n";
  661:     my $answer=<$sclient>;
  662:     chomp($answer);
  663:     $answer="con_lost" if (!$answer);
  664:     return $answer;
  665: }
  666: 
  667: ########################################################
  668: ########################################################
  669: 
  670: =pod
  671: 
  672: =item &reply
  673: 
  674: Sends a command to a server.
  675: 
  676: Inputs: $cmd,$server
  677: 
  678: Returns: The results of the message or 'con_lost' on error.
  679: 
  680: =cut
  681: 
  682: ########################################################
  683: ########################################################
  684: sub reply {
  685:   my ($cmd,$server)=@_;
  686:   my $answer;
  687:   if ($server ne $perlvar{'lonHostID'}) { 
  688:     $answer=subreply($cmd,$server);
  689:     if ($answer eq 'con_lost') {
  690: 	$answer=subreply("ping",$server);
  691:         $answer=subreply($cmd,$server);
  692:     }
  693:   } else {
  694:     $answer='self_reply';
  695:     $answer=subreply($cmd,$server);
  696:   } 
  697:   return $answer;
  698: }
  699: 
  700: ########################################################
  701: ########################################################
  702: 
  703: =pod
  704: 
  705: =item &escape
  706: 
  707: Escape special characters in a string.
  708: 
  709: Inputs: string to escape
  710: 
  711: Returns: The input string with special characters escaped.
  712: 
  713: =cut
  714: 
  715: ########################################################
  716: ########################################################
  717: sub escape {
  718:     my $str=shift;
  719:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
  720:     return $str;
  721: }
  722: 
  723: ########################################################
  724: ########################################################
  725: 
  726: =pod
  727: 
  728: =item &unescape
  729: 
  730: Unescape special characters in a string.
  731: 
  732: Inputs: string to unescape
  733: 
  734: Returns: The input string with special characters unescaped.
  735: 
  736: =cut
  737: 
  738: ########################################################
  739: ########################################################
  740: sub unescape {
  741:     my $str=shift;
  742:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
  743:     return $str;
  744: }
  745: 
  746: ########################################################
  747: ########################################################
  748: 
  749: =pod
  750: 
  751: =item &ishome
  752: 
  753: Determine if the current machine is the home server for a user.
  754: The determination is made by checking the filesystem for the users information.
  755: 
  756: Inputs: $author
  757: 
  758: Returns: 0 - this is not the authors home server, 1 - this is.
  759: 
  760: =cut
  761: 
  762: ########################################################
  763: ########################################################
  764: sub ishome {
  765:     my $author=shift;
  766:     $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
  767:     my ($udom,$uname)=split(/\//,$author);
  768:     my $proname=propath($udom,$uname);
  769:     if (-e $proname) {
  770: 	return 1;
  771:     } else {
  772:         return 0;
  773:     }
  774: }
  775: 
  776: ########################################################
  777: ########################################################
  778: 
  779: =pod
  780: 
  781: =item &propath
  782: 
  783: Inputs: user name, user domain
  784: 
  785: Returns: The full path to the users directory.
  786: 
  787: =cut
  788: 
  789: ########################################################
  790: ########################################################
  791: sub propath {
  792:     my ($udom,$uname)=@_;
  793:     $udom=~s/\W//g;
  794:     $uname=~s/\W//g;
  795:     my $subdir=$uname.'__';
  796:     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
  797:     my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
  798:     return $proname;
  799: } 
  800: 
  801: ########################################################
  802: ########################################################
  803: 
  804: =pod
  805: 
  806: =item &courselog
  807: 
  808: Inputs: $path, $command
  809: 
  810: Returns: unescaped string of values.
  811: 
  812: =cut
  813: 
  814: ########################################################
  815: ########################################################
  816: sub courselog {
  817:     my ($path,$command)=@_;
  818:     my %filters=();
  819:     foreach (split(/\:/,&unescape($command))) {
  820: 	my ($name,$value)=split(/\=/,$_);
  821:         $filters{$name}=$value;
  822:     }
  823:     my @results=();
  824:     open(IN,$path.'/activity.log') or return ('file_error');
  825:     while (my $line=<IN>) {
  826:         chomp($line);
  827:         my ($timestamp,$host,$log)=split(/\:/,$line);
  828: #
  829: # $log has the actual log entries; currently still escaped, and
  830: # %26(timestamp)%3a(url)%3a(user)%3a(domain)
  831: # then additionally
  832: # %3aPOST%3a(name)%3d(value)%3a(name)%3d(value)
  833: # or
  834: # %3aCSTORE%3a(name)%3d(value)%26(name)%3d(value)
  835: #
  836: # get delimiter between timestamped entries to be &&&
  837:         $log=~s/\%26(\d+)\%3a/\&\&\&$1\%3a/g;
  838: # now go over all log entries 
  839:         foreach (split(/\&\&\&/,&unescape($log))) {
  840: 	    my ($time,$res,$uname,$udom,$action,@values)=split(/\:/,$_);
  841:             my $values=&unescape(join(':',@values));
  842:             $values=~s/\&/\:/g;
  843:             $res=&unescape($res);
  844:             my $include=1;
  845:             if (($filters{'username'}) && ($uname ne $filters{'username'})) 
  846:                                                                { $include=0; }
  847:             if (($filters{'domain'}) && ($udom ne $filters{'domain'})) 
  848:                                                                { $include=0; }
  849:             if (($filters{'url'}) && ($res!~/$filters{'url'}/)) 
  850:                                                                { $include=0; }
  851:             if (($filters{'start'}) && ($time<$filters{'start'})) 
  852:                                                                { $include=0; }
  853:             if (($filters{'end'}) && ($time>$filters{'end'})) 
  854:                                                                { $include=0; }
  855:             if (($filters{'action'} eq 'view') && ($action)) 
  856:                                                                { $include=0; }
  857:             if (($filters{'action'} eq 'submit') && ($action ne 'POST')) 
  858:                                                                { $include=0; }
  859:             if (($filters{'action'} eq 'grade') && ($action ne 'CSTORE')) 
  860:                                                                { $include=0; }
  861:             if ($include) {
  862: 	       push(@results,($time<1000000000?'0':'').$time.':'.$res.':'.
  863:                                             $uname.':'.$udom.':'.
  864:                                             $action.':'.$values);
  865:             }
  866:        }
  867:     }
  868:     close IN;
  869:     return join('&',sort(@results));
  870: }
  871: 
  872: ########################################################
  873: ########################################################
  874: 
  875: =pod
  876: 
  877: =item &userlog
  878: 
  879: Inputs: $path, $command
  880: 
  881: Returns: unescaped string of values.
  882: 
  883: =cut
  884: 
  885: ########################################################
  886: ########################################################
  887: sub userlog {
  888:     my ($path,$command)=@_;
  889:     my %filters=();
  890:     foreach (split(/\:/,&unescape($command))) {
  891: 	my ($name,$value)=split(/\=/,$_);
  892:         $filters{$name}=$value;
  893:     }
  894:     my @results=();
  895:     open(IN,$path.'/activity.log') or return ('file_error');
  896:     while (my $line=<IN>) {
  897:         chomp($line);
  898:         my ($timestamp,$host,$log)=split(/\:/,$line);
  899:         $log=&unescape($log);
  900:         my $include=1;
  901:         if (($filters{'start'}) && ($timestamp<$filters{'start'})) 
  902:                                                              { $include=0; }
  903:         if (($filters{'end'}) && ($timestamp>$filters{'end'})) 
  904:                                                              { $include=0; }
  905:         if (($filters{'action'} eq 'log') && ($log!~/^Log/)) { $include=0; }
  906:         if (($filters{'action'} eq 'check') && ($log!~/^Check/)) 
  907:                                                              { $include=0; }
  908:         if ($include) {
  909: 	   push(@results,$timestamp.':'.$log);
  910:         }
  911:     }
  912:     close IN;
  913:     return join('&',sort(@results));
  914: }
  915: 
  916: ########################################################
  917: ########################################################
  918: 
  919: =pod
  920: 
  921: =item Functions required for forking
  922: 
  923: =over 4
  924: 
  925: =item REAPER
  926: 
  927: REAPER takes care of dead children.
  928: 
  929: =item HUNTSMAN
  930: 
  931: Signal handler for SIGINT.
  932: 
  933: =item HUPSMAN
  934: 
  935: Signal handler for SIGHUP
  936: 
  937: =item DISCONNECT
  938: 
  939: Disconnects from database.
  940: 
  941: =back
  942: 
  943: =cut
  944: 
  945: ########################################################
  946: ########################################################
  947: sub REAPER {                   # takes care of dead children
  948:     $SIG{CHLD} = \&REAPER;
  949:     my $pid = wait;
  950:     $children --;
  951:     &logthis("Child $pid died");
  952:     delete $children{$pid};
  953: }
  954: 
  955: sub HUNTSMAN {                      # signal handler for SIGINT
  956:     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
  957:     kill 'INT' => keys %children;
  958:     my $execdir=$perlvar{'lonDaemons'};
  959:     unlink("$execdir/logs/lonsql.pid");
  960:     &logthis("<font color='red'>CRITICAL: Shutting down</font>");
  961:     $unixsock = "mysqlsock";
  962:     my $port="$perlvar{'lonSockDir'}/$unixsock";
  963:     unlink($port);
  964:     exit;                           # clean up with dignity
  965: }
  966: 
  967: sub HUPSMAN {                      # signal handler for SIGHUP
  968:     local($SIG{CHLD}) = 'IGNORE';  # we're going to kill our children
  969:     kill 'INT' => keys %children;
  970:     close($server);                # free up socket
  971:     &logthis("<font color='red'>CRITICAL: Restarting</font>");
  972:     my $execdir=$perlvar{'lonDaemons'};
  973:     $unixsock = "mysqlsock";
  974:     my $port="$perlvar{'lonSockDir'}/$unixsock";
  975:     unlink($port);
  976:     exec("$execdir/lonsql");         # here we go again
  977: }
  978: 
  979: sub DISCONNECT {
  980:     $dbh->disconnect or 
  981:     &logthis("<font color='blue'>WARNING: Couldn't disconnect from database ".
  982:              " $DBI::errstr : $@</font>");
  983:     exit;
  984: }
  985: 
  986: 
  987: =pod
  988: 
  989: =back
  990: 
  991: =cut

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