File:  [LON-CAPA] / loncom / lonsql
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Fri Jul 25 17:07:06 2003 UTC (20 years, 9 months ago) by bowersj2
Branches: MAIN
CVS tags: HEAD
SessionThre2.html from the Guts manual.

    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 1.56 2003/07/25 17:07:06 bowersj2 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: The SQL database in LON-CAPA is used for catalog searches against
   45: resource metadata only. The authoritative version of the resource
   46: metadata is an XML-file on the normal file system (same file name as
   47: resource plus ".meta"). The SQL-database is a cache of these files,
   48: and can be reconstructed from the XML files at any time.
   49: 
   50: The current database is implemented assuming a non-adjustable
   51: architecture involving these data fields (specific to each version of
   52: a resource).
   53: 
   54: =over 4
   55: 
   56: =item * title
   57: 
   58: =item * author
   59: 
   60: =item * subject
   61: 
   62: =item * notes
   63: 
   64: =item * abstract
   65: 
   66: =item * mime
   67: 
   68: =item * language
   69: 
   70: =item * creationdate
   71: 
   72: =item * lastrevisiondate
   73: 
   74: =item * owner
   75: 
   76: =item * copyright 
   77: 
   78: =back 
   79: 
   80: =head2 Purpose within LON-CAPA
   81: 
   82: LON-CAPA is meant to distribute A LOT of educational content to A LOT
   83: of people. It is ineffective to directly rely on contents within the
   84: ext2 filesystem to be speedily scanned for on-the-fly searches of
   85: content descriptions. (Simply put, it takes a cumbersome amount of
   86: time to open, read, analyze, and close thousands of files.)
   87: 
   88: The solution is to index various data fields that are descriptive of
   89: the educational resources on a LON-CAPA server machine in a
   90: database. Descriptive data fields are referred to as "metadata". The
   91: question then arises as to how this metadata is handled in terms of
   92: the rest of the LON-CAPA network without burdening client and daemon
   93: processes.
   94: 
   95: The obvious solution, using lonc to send a query to a lond process,
   96: doesn't work so well in general as you can see in the following
   97: example:
   98: 
   99:     lonc= loncapa client process    A-lonc= a lonc process on Server A
  100:     lond= loncapa daemon process
  101: 
  102:                  database command
  103:     A-lonc  --------TCP/IP----------------> B-lond
  104: 
  105: The problem emerges that A-lonc and B-lond are kept waiting for the
  106: MySQL server to "do its stuff", or in other words, perform the
  107: conceivably sophisticated, data-intensive, time-sucking database
  108: transaction.  By tying up a lonc and lond process, this significantly
  109: cripples the capabilities of LON-CAPA servers.
  110: 
  111: The solution is to offload the work onto another process, and use
  112: lonc and lond just for requests and notifications of completed
  113: processing:
  114: 
  115:                 database command
  116: 
  117:   A-lonc  ---------TCP/IP-----------------> B-lond =====> B-lonsql
  118:          <---------------------------------/                |
  119:            "ok, I'll get back to you..."                    |
  120:                                                             |
  121:                                                             /
  122:   A-lond  <-------------------------------  B-lonc   <======
  123:            "Guess what? I have the result!"
  124: 
  125: Of course, depending on success or failure, the messages may vary, but
  126: the principle remains the same where a separate pool of children
  127: processes (lonsql's) handle the MySQL database manipulations.
  128: 
  129: Thus, lonc and lond spend effectively no time waiting on results from
  130: the database.
  131: 
  132: =head1 Internals
  133: 
  134: =over 4
  135: 
  136: =cut
  137: 
  138: use strict;
  139: 
  140: use lib '/home/httpd/lib/perl/';
  141: use LONCAPA::Configuration;
  142: 
  143: use IO::Socket;
  144: use Symbol;
  145: use POSIX;
  146: use IO::Select;
  147: use IO::File;
  148: use Socket;
  149: use Fcntl;
  150: use Tie::RefHash;
  151: use DBI;
  152: use File::Find;
  153: 
  154: ########################################################
  155: ########################################################
  156: 
  157: =pod
  158: 
  159: =item Global Variables
  160: 
  161: =over 4
  162: 
  163: =item dbh
  164: 
  165: =back
  166: 
  167: =cut
  168: 
  169: ########################################################
  170: ########################################################
  171: my $dbh;
  172: 
  173: ########################################################
  174: ########################################################
  175: 
  176: =pod 
  177: 
  178: =item Variables required for forking
  179: 
  180: =over 4
  181: 
  182: =item $MAX_CLIENTS_PER_CHILD
  183: 
  184: The number of clients each child should process.
  185: 
  186: =item %children 
  187: 
  188: The keys to %children  are the current child process IDs
  189: 
  190: =item $children
  191: 
  192: The current number of children
  193: 
  194: =back
  195: 
  196: =cut 
  197: 
  198: ########################################################
  199: ########################################################
  200: my $MAX_CLIENTS_PER_CHILD  = 5;   # number of clients each child should process
  201: my %children               = ();  # keys are current child process IDs
  202: my $children               = 0;   # current number of children
  203:                                
  204: ###################################################################
  205: ###################################################################
  206: 
  207: =pod
  208: 
  209: =item Main body of code.
  210: 
  211: =over 4
  212: 
  213: =item Read data from loncapa_apache.conf and loncapa.conf.
  214: 
  215: =item Ensure we can access the database.
  216: 
  217: =item Determine if there are other instances of lonsql running.
  218: 
  219: =item Read the hosts file.
  220: 
  221: =item Create a socket for lonsql.
  222: 
  223: =item Fork once and dissociate from parent.
  224: 
  225: =item Write PID to disk.
  226: 
  227: =item Prefork children and maintain the population of children.
  228: 
  229: =back
  230: 
  231: =cut
  232: 
  233: ###################################################################
  234: ###################################################################
  235: my $childmaxattempts=10;
  236: my $run =0;              # running counter to generate the query-id
  237: #
  238: # Read loncapa_apache.conf and loncapa.conf
  239: #
  240: my $perlvarref=LONCAPA::Configuration::read_conf('loncapa.conf');
  241: my %perlvar=%{$perlvarref};
  242: #
  243: # Make sure that database can be accessed
  244: #
  245: my $dbh;
  246: unless ($dbh = DBI->connect("DBI:mysql:loncapa","www",
  247:                             $perlvar{'lonSqlAccess'},
  248:                             { RaiseError =>0,PrintError=>0})) { 
  249:     print "Cannot connect to database!\n";
  250:     my $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
  251:     my $subj="LON: $perlvar{'lonHostID'} Cannot connect to database!";
  252:     system("echo 'Cannot connect to MySQL database!' |".
  253:            " mailto $emailto -s '$subj' > /dev/null");
  254:     exit 1;
  255: } else {
  256:     $dbh->disconnect;
  257: }
  258: 
  259: #
  260: # Check if other instance running
  261: #
  262: my $pidfile="$perlvar{'lonDaemons'}/logs/lonsql.pid";
  263: if (-e $pidfile) {
  264:    my $lfh=IO::File->new("$pidfile");
  265:    my $pide=<$lfh>;
  266:    chomp($pide);
  267:    if (kill 0 => $pide) { die "already running"; }
  268: }
  269: 
  270: #
  271: # Read hosts file
  272: #
  273: my %hostip;
  274: my $thisserver;
  275: my $PREFORK=4; # number of children to maintain, at least four spare
  276: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
  277: while (my $configline=<CONFIG>) {
  278:     my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
  279:     chomp($ip);
  280:     $hostip{$ip}=$id;
  281:     $thisserver=$name if ($id eq $perlvar{'lonHostID'});
  282:     $PREFORK++;
  283: }
  284: close(CONFIG);
  285: #
  286: $PREFORK=int($PREFORK/4);
  287: 
  288: #
  289: # Create a socket to talk to lond
  290: #
  291: my $unixsock = "mysqlsock";
  292: my $localfile="$perlvar{'lonSockDir'}/$unixsock";
  293: my $server;
  294: unlink ($localfile);
  295: unless ($server=IO::Socket::UNIX->new(Local    =>"$localfile",
  296:                                       Type    => SOCK_STREAM,
  297:                                       Listen => 10)) {
  298:     print "in socket error:$@\n";
  299: }
  300: 
  301: #
  302: # Fork once and dissociate
  303: #
  304: my $fpid=fork;
  305: exit if $fpid;
  306: die "Couldn't fork: $!" unless defined ($fpid);
  307: POSIX::setsid() or die "Can't start new session: $!";
  308: 
  309: #
  310: # Write our PID on disk
  311: my $execdir=$perlvar{'lonDaemons'};
  312: open (PIDSAVE,">$execdir/logs/lonsql.pid");
  313: print PIDSAVE "$$\n";
  314: close(PIDSAVE);
  315: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
  316: 
  317: #
  318: # Ignore signals generated during initial startup
  319: $SIG{HUP}=$SIG{USR1}='IGNORE';
  320: # Now we are on our own    
  321: #    Fork off our children.
  322: for (1 .. $PREFORK) {
  323:     make_new_child();
  324: }
  325: 
  326: #
  327: # Install signal handlers.
  328: $SIG{CHLD} = \&REAPER;
  329: $SIG{INT}  = $SIG{TERM} = \&HUNTSMAN;
  330: $SIG{HUP}  = \&HUPSMAN;
  331: 
  332: #
  333: # And maintain the population.
  334: while (1) {
  335:     sleep;                          # wait for a signal (i.e., child's death)
  336:     for (my $i = $children; $i < $PREFORK; $i++) {
  337:         make_new_child();           # top up the child pool
  338:     }
  339: }
  340: 
  341: ########################################################
  342: ########################################################
  343: 
  344: =pod
  345: 
  346: =item &make_new_child
  347: 
  348: Inputs: None
  349: 
  350: Returns: None
  351: 
  352: =cut
  353: 
  354: ########################################################
  355: ########################################################
  356: sub make_new_child {
  357:     my $pid;
  358:     my $sigset;
  359:     #
  360:     # block signal for fork
  361:     $sigset = POSIX::SigSet->new(SIGINT);
  362:     sigprocmask(SIG_BLOCK, $sigset)
  363:         or die "Can't block SIGINT for fork: $!\n";
  364:     #
  365:     die "fork: $!" unless defined ($pid = fork);
  366:     #
  367:     if ($pid) {
  368:         # Parent records the child's birth and returns.
  369:         sigprocmask(SIG_UNBLOCK, $sigset)
  370:             or die "Can't unblock SIGINT for fork: $!\n";
  371:         $children{$pid} = 1;
  372:         $children++;
  373:         return;
  374:     } else {
  375:         # Child can *not* return from this subroutine.
  376:         $SIG{INT} = 'DEFAULT';      # make SIGINT kill us as it did before
  377:         # unblock signals
  378:         sigprocmask(SIG_UNBLOCK, $sigset)
  379:             or die "Can't unblock SIGINT for fork: $!\n";
  380:         #open database handle
  381: 	# making dbh global to avoid garbage collector
  382: 	unless ($dbh = DBI->connect("DBI:mysql:loncapa","www",
  383:                                     $perlvar{'lonSqlAccess'},
  384:                                     { RaiseError =>0,PrintError=>0})) { 
  385:             sleep(10+int(rand(20)));
  386:             &logthis("<font color=blue>WARNING: Couldn't connect to database".
  387:                      ": $@</font>");
  388:                      #  "($st secs): $@</font>");
  389:             print "database handle error\n";
  390:             exit;
  391:         }
  392: 	# make sure that a database disconnection occurs with 
  393:         # ending kill signals
  394: 	$SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
  395:         # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
  396:         for (my $i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
  397:             my $client = $server->accept() or last;
  398:             # do something with the connection
  399: 	    $run = $run+1;
  400: 	    my $userinput = <$client>;
  401: 	    chomp($userinput);
  402:             #
  403: 	    my ($conserver,$query,
  404: 		$arg1,$arg2,$arg3)=split(/&/,$userinput);
  405: 	    my $query=unescape($query);
  406:             #
  407:             #send query id which is pid_unixdatetime_runningcounter
  408: 	    my $queryid = $thisserver;
  409: 	    $queryid .="_".($$)."_";
  410: 	    $queryid .= time."_";
  411: 	    $queryid .= $run;
  412: 	    print $client "$queryid\n";
  413: 	    #
  414: 	    &logthis("QUERY: $query - $arg1 - $arg2 - $arg3");
  415: 	    sleep 1;
  416:             #
  417:             my $result='';
  418:             #
  419:             # At this point, query is received, query-ID assigned and sent 
  420:             # back, $query eq 'logquery' will mean that this is a query 
  421:             # against log-files
  422:             if (($query eq 'userlog') || ($query eq 'courselog')) {
  423:                 # beginning of log query
  424:                 my $udom    = &unescape($arg1);
  425:                 my $uname   = &unescape($arg2);
  426:                 my $command = &unescape($arg3);
  427:                 my $path    = &propath($udom,$uname);
  428:                 if (-e "$path/activity.log") {
  429:                     if ($query eq 'userlog') {
  430:                         $result=&userlog($path,$command);
  431:                     } else {
  432:                         $result=&courselog($path,$command);
  433:                     }
  434:                 } else {
  435:                     &logthis('Unable to do log query: '.$uname.'@'.$udom);
  436:                     $result='no_such_file';
  437:                 }
  438:                 # end of log query
  439:             } else {
  440:                 # Do an sql query
  441:                 $result = &do_sql_query($query,$arg1,$arg2);
  442:             }
  443:             # result does not need to be escaped because it has already been
  444:             # escaped.
  445:             #$result=&escape($result);
  446:             # reply with result, append \n unless already there
  447: 	    $result.="\n" unless ($result=~/\n$/);
  448:             &reply("queryreply:$queryid:$result",$conserver);
  449:         }
  450:         # tidy up gracefully and finish
  451:         #
  452:         # close the database handle
  453: 	$dbh->disconnect
  454:             or &logthis("<font color=blue>WARNING: Couldn't disconnect".
  455:                         " from database  $DBI::errstr : $@</font>");
  456:         # this exit is VERY important, otherwise the child will become
  457:         # a producer of more and more children, forking yourself into
  458:         # process death.
  459:         exit;
  460:     }
  461: }
  462: 
  463: ########################################################
  464: ########################################################
  465: 
  466: =pod
  467: 
  468: =item &do_sql_query
  469: 
  470: Runs an sql metadata table query.
  471: 
  472: Inputs: $query, $custom, $customshow
  473: 
  474: Returns: A string containing escaped results.
  475: 
  476: =cut
  477: 
  478: ########################################################
  479: ########################################################
  480: {
  481:     my @metalist;
  482: 
  483: sub process_file {
  484:     if ( -e $_ &&  # file exists
  485:          -f $_ &&  # and is a normal file
  486:          /\.meta$/ &&  # ends in meta
  487:          ! /^.+\.\d+\.[^\.]+\.meta$/  # is not a previous version
  488:          ) {
  489:         push(@metalist,$File::Find::name);
  490:     }
  491: }
  492: 
  493: sub do_sql_query {
  494:     my ($query,$custom,$customshow) = @_;
  495:     $custom     = &unescape($custom);
  496:     $customshow = &unescape($customshow);
  497:     #
  498:     @metalist = ();
  499:     #
  500:     my $result = '';
  501:     my @results = ();
  502:     my @files;
  503:     my $subsetflag=0;
  504:     #
  505:     if ($query) {
  506:         #prepare and execute the query
  507:         my $sth = $dbh->prepare($query);
  508:         unless ($sth->execute()) {
  509:             &logthis("<font color=blue>WARNING: ".
  510:                      "Could not retrieve from database: $@</font>");
  511:         } else {
  512:             my $aref=$sth->fetchall_arrayref;
  513:             foreach my $row (@$aref) {
  514:                 push @files,@{$row}[3] if ($custom or $customshow);
  515:                 my @b=map { &escape($_); } @$row;
  516:                 push @results,join(",", @b);
  517:                 # Build up the @files array with the LON-CAPA urls 
  518:                 # of the resources.
  519:             }
  520:         }
  521:     }
  522:     # do custom metadata searching here and build into result
  523:     return join("&",@results) if (! ($custom or $customshow));
  524:     # Only get here if there is a custom query or custom show request
  525:     &logthis("Doing custom query for $custom");
  526:     if ($query) {
  527:         @metalist=map {
  528:             $perlvar{'lonDocRoot'}.$_.'.meta';
  529:         } @files;
  530:     } else {
  531:         my $dir = "$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}";
  532:         @metalist=(); 
  533:         opendir(RESOURCES,$dir);
  534:         my @homeusers=grep {
  535:             &ishome($dir.'/'.$_);
  536:         } grep {!/^\.\.?$/} readdir(RESOURCES);
  537:         closedir RESOURCES;
  538:         # Define the
  539:         foreach my $user (@homeusers) {
  540:             find (\&process_file,$dir.'/'.$user);
  541:         }
  542:     } 
  543:     # if file is indicated in sql database and
  544:     #     not part of sql-relevant query, do not pattern match.
  545:     #
  546:     # if file is not in sql database, output error.
  547:     #
  548:     # if file is indicated in sql database and is
  549:     #     part of query result list, then do the pattern match.
  550:     my $customresult='';
  551:     my @results;
  552:     foreach my $metafile (@metalist) {
  553:         my $fh=IO::File->new($metafile);
  554:         my @lines=<$fh>;
  555:         my $stuff=join('',@lines);
  556:         if ($stuff=~/$custom/s) {
  557:             foreach my $f ('abstract','author','copyright',
  558:                            'creationdate','keywords','language',
  559:                            'lastrevisiondate','mime','notes',
  560:                            'owner','subject','title') {
  561:                 $stuff=~s/\n?\<$f[^\>]*\>.*?<\/$f[^\>]*\>\n?//s;
  562:             }
  563:             my $mfile=$metafile; 
  564:             my $docroot=$perlvar{'lonDocRoot'};
  565:             $mfile=~s/^$docroot//;
  566:             $mfile=~s/\.meta$//;
  567:             unless ($query) {
  568:                 my $q2="SELECT * FROM metadata WHERE url ".
  569:                     " LIKE BINARY '?'";
  570:                 my $sth = $dbh->prepare($q2);
  571:                 $sth->execute($mfile);
  572:                 my $aref=$sth->fetchall_arrayref;
  573:                 foreach my $a (@$aref) {
  574:                     my @b=map { &escape($_)} @$a;
  575:                     push @results,join(",", @b);
  576:                 }
  577:             }
  578:             # &logthis("found: $stuff");
  579:             $customresult.='&custom='.&escape($mfile).','.
  580:                 escape($stuff);
  581:         }
  582:     }
  583:     $result=join("&",@results) unless $query;
  584:     $result.=$customresult;
  585:     #
  586:     return $result;
  587: } # End of &do_sql_query
  588: 
  589: } # End of scoping curly braces for &process_file and &do_sql_query
  590: ########################################################
  591: ########################################################
  592: 
  593: =pod
  594: 
  595: =item &logthis
  596: 
  597: Inputs: $message, the message to log
  598: 
  599: Returns: nothing
  600: 
  601: Writes $message to the logfile.
  602: 
  603: =cut
  604: 
  605: ########################################################
  606: ########################################################
  607: sub logthis {
  608:     my $message=shift;
  609:     my $execdir=$perlvar{'lonDaemons'};
  610:     my $fh=IO::File->new(">>$execdir/logs/lonsql.log");
  611:     my $now=time;
  612:     my $local=localtime($now);
  613:     print $fh "$local ($$): $message\n";
  614: }
  615: 
  616: # -------------------------------------------------- Non-critical communication
  617: 
  618: ########################################################
  619: ########################################################
  620: 
  621: =pod
  622: 
  623: =item &subreply
  624: 
  625: Sends a command to a server.  Called only by &reply.
  626: 
  627: Inputs: $cmd,$server
  628: 
  629: Returns: The results of the message or 'con_lost' on error.
  630: 
  631: =cut
  632: 
  633: ########################################################
  634: ########################################################
  635: sub subreply {
  636:     my ($cmd,$server)=@_;
  637:     my $peerfile="$perlvar{'lonSockDir'}/$server";
  638:     my $sclient=IO::Socket::UNIX->new(Peer    =>"$peerfile",
  639:                                       Type    => SOCK_STREAM,
  640:                                       Timeout => 10)
  641:        or return "con_lost";
  642:     print $sclient "$cmd\n";
  643:     my $answer=<$sclient>;
  644:     chomp($answer);
  645:     $answer="con_lost" if (!$answer);
  646:     return $answer;
  647: }
  648: 
  649: ########################################################
  650: ########################################################
  651: 
  652: =pod
  653: 
  654: =item &reply
  655: 
  656: Sends a command to a server.
  657: 
  658: Inputs: $cmd,$server
  659: 
  660: Returns: The results of the message or 'con_lost' on error.
  661: 
  662: =cut
  663: 
  664: ########################################################
  665: ########################################################
  666: sub reply {
  667:   my ($cmd,$server)=@_;
  668:   my $answer;
  669:   if ($server ne $perlvar{'lonHostID'}) { 
  670:     $answer=subreply($cmd,$server);
  671:     if ($answer eq 'con_lost') {
  672: 	$answer=subreply("ping",$server);
  673:         $answer=subreply($cmd,$server);
  674:     }
  675:   } else {
  676:     $answer='self_reply';
  677:     $answer=subreply($cmd,$server);
  678:   } 
  679:   return $answer;
  680: }
  681: 
  682: ########################################################
  683: ########################################################
  684: 
  685: =pod
  686: 
  687: =item &escape
  688: 
  689: Escape special characters in a string.
  690: 
  691: Inputs: string to escape
  692: 
  693: Returns: The input string with special characters escaped.
  694: 
  695: =cut
  696: 
  697: ########################################################
  698: ########################################################
  699: sub escape {
  700:     my $str=shift;
  701:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
  702:     return $str;
  703: }
  704: 
  705: ########################################################
  706: ########################################################
  707: 
  708: =pod
  709: 
  710: =item &unescape
  711: 
  712: Unescape special characters in a string.
  713: 
  714: Inputs: string to unescape
  715: 
  716: Returns: The input string with special characters unescaped.
  717: 
  718: =cut
  719: 
  720: ########################################################
  721: ########################################################
  722: sub unescape {
  723:     my $str=shift;
  724:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
  725:     return $str;
  726: }
  727: 
  728: ########################################################
  729: ########################################################
  730: 
  731: =pod
  732: 
  733: =item &ishome
  734: 
  735: Determine if the current machine is the home server for a user.
  736: The determination is made by checking the filesystem for the users information.
  737: 
  738: Inputs: $author
  739: 
  740: Returns: 0 - this is not the authors home server, 1 - this is.
  741: 
  742: =cut
  743: 
  744: ########################################################
  745: ########################################################
  746: sub ishome {
  747:     my $author=shift;
  748:     $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
  749:     my ($udom,$uname)=split(/\//,$author);
  750:     my $proname=propath($udom,$uname);
  751:     if (-e $proname) {
  752: 	return 1;
  753:     } else {
  754:         return 0;
  755:     }
  756: }
  757: 
  758: ########################################################
  759: ########################################################
  760: 
  761: =pod
  762: 
  763: =item &propath
  764: 
  765: Inputs: user name, user domain
  766: 
  767: Returns: The full path to the users directory.
  768: 
  769: =cut
  770: 
  771: ########################################################
  772: ########################################################
  773: sub propath {
  774:     my ($udom,$uname)=@_;
  775:     $udom=~s/\W//g;
  776:     $uname=~s/\W//g;
  777:     my $subdir=$uname.'__';
  778:     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
  779:     my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
  780:     return $proname;
  781: } 
  782: 
  783: ########################################################
  784: ########################################################
  785: 
  786: =pod
  787: 
  788: =item &courselog
  789: 
  790: Inputs: $path, $command
  791: 
  792: Returns: unescaped string of values.
  793: 
  794: =cut
  795: 
  796: ########################################################
  797: ########################################################
  798: sub courselog {
  799:     my ($path,$command)=@_;
  800:     my %filters=();
  801:     foreach (split(/\:/,&unescape($command))) {
  802: 	my ($name,$value)=split(/\=/,$_);
  803:         $filters{$name}=$value;
  804:     }
  805:     my @results=();
  806:     open(IN,$path.'/activity.log') or return ('file_error');
  807:     while (my $line=<IN>) {
  808:         chomp($line);
  809:         my ($timestamp,$host,$log)=split(/\:/,$line);
  810: #
  811: # $log has the actual log entries; currently still escaped, and
  812: # %26(timestamp)%3a(url)%3a(user)%3a(domain)
  813: # then additionally
  814: # %3aPOST%3a(name)%3d(value)%3a(name)%3d(value)
  815: # or
  816: # %3aCSTORE%3a(name)%3d(value)%26(name)%3d(value)
  817: #
  818: # get delimiter between timestamped entries to be &&&
  819:         $log=~s/\%26(\d+)\%3a/\&\&\&$1\%3a/g;
  820: # now go over all log entries 
  821:         foreach (split(/\&\&\&/,&unescape($log))) {
  822: 	    my ($time,$res,$uname,$udom,$action,@values)=split(/\:/,$_);
  823:             my $values=&unescape(join(':',@values));
  824:             $values=~s/\&/\:/g;
  825:             $res=&unescape($res);
  826:             my $include=1;
  827:             if (($filters{'username'}) && ($uname ne $filters{'username'})) 
  828:                                                                { $include=0; }
  829:             if (($filters{'domain'}) && ($udom ne $filters{'domain'})) 
  830:                                                                { $include=0; }
  831:             if (($filters{'url'}) && ($res!~/$filters{'url'}/)) 
  832:                                                                { $include=0; }
  833:             if (($filters{'start'}) && ($time<$filters{'start'})) 
  834:                                                                { $include=0; }
  835:             if (($filters{'end'}) && ($time>$filters{'end'})) 
  836:                                                                { $include=0; }
  837:             if (($filters{'action'} eq 'view') && ($action)) 
  838:                                                                { $include=0; }
  839:             if (($filters{'action'} eq 'submit') && ($action ne 'POST')) 
  840:                                                                { $include=0; }
  841:             if (($filters{'action'} eq 'grade') && ($action ne 'CSTORE')) 
  842:                                                                { $include=0; }
  843:             if ($include) {
  844: 	       push(@results,($time<1000000000?'0':'').$time.':'.$res.':'.
  845:                                             $uname.':'.$udom.':'.
  846:                                             $action.':'.$values);
  847:             }
  848:        }
  849:     }
  850:     close IN;
  851:     return join('&',sort(@results));
  852: }
  853: 
  854: ########################################################
  855: ########################################################
  856: 
  857: =pod
  858: 
  859: =item &userlog
  860: 
  861: Inputs: $path, $command
  862: 
  863: Returns: unescaped string of values.
  864: 
  865: =cut
  866: 
  867: ########################################################
  868: ########################################################
  869: sub userlog {
  870:     my ($path,$command)=@_;
  871:     my %filters=();
  872:     foreach (split(/\:/,&unescape($command))) {
  873: 	my ($name,$value)=split(/\=/,$_);
  874:         $filters{$name}=$value;
  875:     }
  876:     my @results=();
  877:     open(IN,$path.'/activity.log') or return ('file_error');
  878:     while (my $line=<IN>) {
  879:         chomp($line);
  880:         my ($timestamp,$host,$log)=split(/\:/,$line);
  881:         $log=&unescape($log);
  882:         my $include=1;
  883:         if (($filters{'start'}) && ($timestamp<$filters{'start'})) 
  884:                                                              { $include=0; }
  885:         if (($filters{'end'}) && ($timestamp>$filters{'end'})) 
  886:                                                              { $include=0; }
  887:         if (($filters{'action'} eq 'log') && ($log!~/^Log/)) { $include=0; }
  888:         if (($filters{'action'} eq 'check') && ($log!~/^Check/)) 
  889:                                                              { $include=0; }
  890:         if ($include) {
  891: 	   push(@results,$timestamp.':'.$log);
  892:         }
  893:     }
  894:     close IN;
  895:     return join('&',sort(@results));
  896: }
  897: 
  898: ########################################################
  899: ########################################################
  900: 
  901: =pod
  902: 
  903: =item Functions required for forking
  904: 
  905: =over 4
  906: 
  907: =item REAPER
  908: 
  909: REAPER takes care of dead children.
  910: 
  911: =item HUNTSMAN
  912: 
  913: Signal handler for SIGINT.
  914: 
  915: =item HUPSMAN
  916: 
  917: Signal handler for SIGHUP
  918: 
  919: =item DISCONNECT
  920: 
  921: Disconnects from database.
  922: 
  923: =back
  924: 
  925: =cut
  926: 
  927: ########################################################
  928: ########################################################
  929: sub REAPER {                   # takes care of dead children
  930:     $SIG{CHLD} = \&REAPER;
  931:     my $pid = wait;
  932:     $children --;
  933:     &logthis("Child $pid died");
  934:     delete $children{$pid};
  935: }
  936: 
  937: sub HUNTSMAN {                      # signal handler for SIGINT
  938:     local($SIG{CHLD}) = 'IGNORE';   # we're going to kill our children
  939:     kill 'INT' => keys %children;
  940:     my $execdir=$perlvar{'lonDaemons'};
  941:     unlink("$execdir/logs/lonsql.pid");
  942:     &logthis("<font color=red>CRITICAL: Shutting down</font>");
  943:     $unixsock = "mysqlsock";
  944:     my $port="$perlvar{'lonSockDir'}/$unixsock";
  945:     unlink($port);
  946:     exit;                           # clean up with dignity
  947: }
  948: 
  949: sub HUPSMAN {                      # signal handler for SIGHUP
  950:     local($SIG{CHLD}) = 'IGNORE';  # we're going to kill our children
  951:     kill 'INT' => keys %children;
  952:     close($server);                # free up socket
  953:     &logthis("<font color=red>CRITICAL: Restarting</font>");
  954:     my $execdir=$perlvar{'lonDaemons'};
  955:     $unixsock = "mysqlsock";
  956:     my $port="$perlvar{'lonSockDir'}/$unixsock";
  957:     unlink($port);
  958:     exec("$execdir/lonsql");         # here we go again
  959: }
  960: 
  961: sub DISCONNECT {
  962:     $dbh->disconnect or 
  963:     &logthis("<font color=blue>WARNING: Couldn't disconnect from database ".
  964:              " $DBI::errstr : $@</font>");
  965:     exit;
  966: }
  967: 
  968: 
  969: 
  970: 
  971: 
  972: 
  973: 
  974: 
  975: 
  976: 
  977: 
  978: # ----------------------------------- POD (plain old documentation, CPAN style)
  979: 
  980: =pod
  981: 
  982: =back
  983: 
  984: =cut

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