Annotation of loncom/LONCAPA.pm, revision 1.27

1.1       albertel    1: # The LearningOnline Network
                      2: # Base routines
                      3: #
1.27    ! jms         4: # $Id: LONCAPA.pm,v 1.26 2008/11/17 13:24:02 jms Exp $
1.1       albertel    5: #
                      6: # Copyright Michigan State University Board of Trustees
                      7: #
                      8: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
                      9: #
                     10: # LON-CAPA is free software; you can redistribute it and/or modify
                     11: # it under the terms of the GNU General Public License as published by
                     12: # the Free Software Foundation; either version 2 of the License, or
                     13: # (at your option) any later version.
                     14: #
                     15: # LON-CAPA is distributed in the hope that it will be useful,
                     16: # but WITHOUT ANY WARRANTY; without even the implied warranty of
                     17: # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
                     18: # GNU General Public License for more details.
                     19: #
                     20: # You should have received a copy of the GNU General Public License
                     21: # along with LON-CAPA; if not, write to the Free Software
                     22: # Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
                     23: #
                     24: # /home/httpd/html/adm/gpl.txt
                     25: #
                     26: # http://www.lon-capa.org/
                     27: #
                     28: ###
                     29: 
1.25      jms        30: 
                     31: 
1.1       albertel   32: package LONCAPA;
                     33: 
                     34: use strict;
1.2       www        35: use lib '/home/httpd/lib/perl/';
                     36: use LONCAPA::Configuration;
                     37: use Fcntl qw(:flock);
                     38: use GDBM_File;
                     39: use POSIX;
                     40: 
                     41: my $loncapa_max_wait_time = 13;
                     42: 
1.14      albertel   43: 
                     44: use vars qw($match_domain   $match_not_domain
                     45: 	    $match_username $match_not_username
1.16      albertel   46: 	    $match_courseid $match_not_courseid
                     47: 	    $match_name
1.23      albertel   48:             $match_lonid
1.14      albertel   49: 	    $match_handle   $match_not_handle);
                     50: 
1.1       albertel   51: require Exporter;
                     52: our @ISA = qw (Exporter);
1.14      albertel   53: our @EXPORT = qw(&add_get_param    &escape            &unescape       
                     54: 		 &tie_domain_hash  &untie_domain_hash &tie_user_hash
                     55: 		 &untie_user_hash  &propath);
                     56: our @EXPORT_OK = qw($match_domain   $match_not_domain
                     57: 		    $match_username $match_not_username
1.16      albertel   58: 		    $match_courseid $match_not_courseid
                     59: 		    $match_name
1.23      albertel   60: 		    $match_lonid
1.14      albertel   61: 		    $match_handle   $match_not_handle);
                     62: our %EXPORT_TAGS = ( 'match' =>[qw($match_domain   $match_not_domain
                     63: 				   $match_username $match_not_username
1.16      albertel   64: 				   $match_courseid $match_not_courseid
                     65: 				   $match_name
1.23      albertel   66: 				   $match_lonid
1.14      albertel   67: 				   $match_handle   $match_not_handle)],);
1.2       www        68: my %perlvar;
1.1       albertel   69: 
1.8       foxr       70: 
1.26      jms        71: =pod
                     72: 
                     73: =head2 NOTE:
1.8       foxr       74: 
1.26      jms        75: add_get_param()
                     76: 
                     77: Inputs are a url, and a hash ref of
                     78: form name => value pairs
                     79: takes care of properly adding the form name elements and values to the 
                     80: the url doing proper escaping of the values and joining with ? or & as 
                     81: needed
                     82: 
                     83: =cut
1.1       albertel   84: 
                     85: sub add_get_param {
                     86:     my ($url,$form_data) = @_;
                     87:     my $needs_question_mark = ($url !~ /\?/);
                     88: 
                     89:     while (my ($name,$value) = each(%$form_data)) {
                     90: 	if ($needs_question_mark) {
                     91: 	    $url.='?';
                     92: 	    $needs_question_mark = 0;
                     93: 	} else { 
                     94: 	    $url.='&';
                     95: 	}
                     96: 	$url.=$name.'='.&escape($form_data->{$name});
                     97:     }
                     98:     return $url;
                     99: }
                    100: 
                    101: # -------------------------------------------------------- Escape Special Chars
                    102: 
                    103: sub escape {
                    104:     my $str=shift;
                    105:     $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
                    106:     return $str;
                    107: }
                    108: 
                    109: # ----------------------------------------------------- Un-Escape Special Chars
                    110: 
                    111: sub unescape {
                    112:     my $str=shift;
                    113:     $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
                    114:     return $str;
                    115: }
                    116: 
1.14      albertel  117: $match_domain     = $LONCAPA::domain_re     = qr{[\w\-.]+};
                    118: $match_not_domain = $LONCAPA::not_domain_re = qr{[^\w\-.]+};
                    119: sub clean_domain {
                    120:     my ($domain) = @_;
                    121:     $domain =~ s/$match_not_domain//g;
                    122:     return $domain;
                    123: }
                    124: 
1.24      albertel  125: $match_username     = $LONCAPA::username_re     = qr{\w[\w\-.@]+};
                    126: $match_not_username = $LONCAPA::not_username_re = qr{[^\w\-.@]+};
1.14      albertel  127: sub clean_username {
                    128:     my ($username) = @_;
1.21      albertel  129:     $username =~ s/^\W+//;
1.14      albertel  130:     $username =~ s/$match_not_username//g;
                    131:     return $username;
                    132: }
                    133: 
1.16      albertel  134: 
                    135: $match_courseid     = $LONCAPA::courseid_re     = qr{\d[\w\-.]+};
                    136: $match_not_courseid = $LONCAPA::not_courseid_re = qr{[^\w\-.]+};
1.22      albertel  137: sub clean_courseid {
                    138:     my ($courseid) = @_;
                    139:     $courseid =~ s/^\D+//;
                    140:     $courseid =~ s/$match_not_courseid//g;
                    141:     return $courseid;
                    142: }
1.16      albertel  143: 
1.22      albertel  144: $match_name         = $LONCAPA::name_re = qr{$match_username|$match_courseid};
1.16      albertel  145: sub clean_name {
                    146:     my ($name) = @_;
                    147:     $name =~ s/$match_not_username//g;
                    148:     return $name;
                    149: }
                    150: 
1.23      albertel  151: $match_lonid     = $LONCAPA::lonid_re     = qr{[\w\-.]+};
                    152: 
1.16      albertel  153: sub split_courseid {
                    154:     my ($courseid) = @_;
                    155:     my  ($domain,$coursenum) = 
                    156: 	($courseid=~m{^/($match_domain)/($match_courseid)});
                    157:     return ($domain,$coursenum);
                    158: }
                    159: 
1.24      albertel  160: $match_handle     = $LONCAPA::handle_re     = qr{[\w\-.@]+};
                    161: $match_not_handle = $LONCAPA::not_handle_re = qr{[^\w\-.@]+};
1.14      albertel  162: sub clean_handle {
                    163:     my ($handle) = @_;
                    164:     $handle =~ s/$match_not_handle//g;
                    165:     return $handle;
                    166: }
                    167: 
1.2       www       168: # -------------------------------------------- Return path to profile directory
                    169: 
                    170: sub propath {
                    171:     my ($udom,$uname)=@_;
1.14      albertel  172:     $udom = &clean_domain($udom);
1.16      albertel  173:     $uname= &clean_name($uname);
1.2       www       174:     my $subdir=$uname.'__';
                    175:     $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
                    176:     my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
                    177:     return $proname;
                    178: } 
                    179: 
                    180: 
                    181: sub tie_domain_hash {
                    182:     my ($domain,$namespace,$how,$loghead,$logtail) = @_;
                    183:     
                    184:     # Filter out any whitespace in the domain name:
                    185:     
1.14      albertel  186:     $domain = &clean_domain($domain);
1.2       www       187:     
                    188:     # We have enough to go on to tie the hash:
                    189:     
                    190:     my $user_top_dir   = $perlvar{'lonUsersDir'};
                    191:     my $domain_dir     = $user_top_dir."/$domain";
                    192:     my $resource_file  = $domain_dir."/$namespace";
                    193:     return &_locking_hash_tie($resource_file,$namespace,$how,$loghead,$logtail);
                    194: }
                    195: 
                    196: sub untie_domain_hash {
                    197:     return &_locking_hash_untie(@_);
                    198: }
1.25      jms       199: 
                    200: 
1.2       www       201: sub tie_user_hash {
                    202:     my ($domain,$user,$namespace,$how,$loghead,$what) = @_;
                    203: 
1.15      albertel  204:     $namespace=~s{/}{_}g;	# / -> _
                    205:     $namespace     = &clean_username($namespace);
                    206:     my $proname    = &propath($domain, $user);
1.2       www       207:     my $file_prefix="$proname/$namespace";
                    208:     return &_locking_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
                    209: }
                    210: 
                    211: sub untie_user_hash {
                    212:     return &_locking_hash_untie(@_);
                    213: }
                    214: 
1.6       www       215: 
                    216: sub locking_hash_tie {
                    217:     my ($filename,$how)=@_;
                    218:     my ($file_prefix,$namespace)=&db_filename_parts($filename);
1.7       albertel  219:     if ($namespace eq '') { return undef; }
1.6       www       220:     return &_locking_hash_tie($file_prefix,$namespace,$how);
                    221: }
                    222: 
                    223: sub locking_hash_untie {
                    224:     return &_locking_hash_untie(@_);
                    225: }
                    226: 
                    227: sub db_filename_parts {
                    228:     my ($filename)=@_;
                    229:     my ($file_path,$namespace)=($filename=~/^(.*)\/([^\/]+)\.db$/);
1.7       albertel  230:     if ($namespace eq '') { return undef; }
1.6       www       231:     return ($file_path.'/'.$namespace,$namespace);
                    232: }
                    233: 
1.2       www       234: # internal routines that handle the actual tieing and untieing process
                    235: 
                    236: sub _do_hash_tie {
                    237:     my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
                    238:     my %hash;
                    239:     if(tie(%hash, 'GDBM_File', "$file_prefix.db", $how, 0640)) {
                    240: 	# If this is a namespace for which a history is kept,
                    241: 	# make the history log entry:    
                    242: 	if (($namespace !~/^nohist\_/) && (defined($loghead))) {
                    243: 	    my $hfh = IO::File->new(">>$file_prefix.hist"); 
                    244: 	    if($hfh) {
1.5       albertel  245: 		my $now = time();
                    246: 		print $hfh ("$loghead:$now:$what\n");
1.2       www       247: 	    }
                    248: 	    $hfh->close;
                    249: 	}
                    250: 	return \%hash;
                    251:     } else {
                    252: 	return undef;
                    253:     }
                    254: }
                    255: 
                    256: sub _do_hash_untie {
                    257:     my ($hashref) = @_;
                    258:     my $result = untie(%$hashref);
                    259:     return $result;
                    260: }
                    261: 
                    262: {
                    263:     my $sym;
1.10      albertel  264:     my @pushed_syms;
1.11      albertel  265: 
                    266:     sub clean_sym {
                    267: 	undef($sym);
                    268:     }
1.10      albertel  269:     sub push_locking_hash_tie {
                    270: 	if (!defined($sym)) {
                    271: 	    die("Invalid used of push_locking_hash_tie, should only be called after a lock has occurred and before and unlock.");
                    272: 	}
                    273: 	push(@pushed_syms,$sym);
                    274: 	undef($sym);
                    275:     }
                    276: 
                    277:     sub pop_locking_hash_tie {
                    278: 	if (defined($sym)) {
                    279: 	    die("Invalid nested used of pop_locking_hash_tie, should only be called after a unlock has occurred.");
                    280: 	}
                    281: 	$sym = pop(@pushed_syms);
                    282:     }
1.2       www       283: 
                    284:     sub _locking_hash_tie {
                    285: 	my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
1.9       albertel  286: 	if (defined($sym)) {
1.11      albertel  287: 	    die('Nested locking attempted without proper use of push_locking_hash_tie, this is unsupported');
1.9       albertel  288: 	}
                    289: 
1.2       www       290:         my $lock_type=LOCK_SH;
                    291: # Are we reading or writing?
                    292:         if ($how eq &GDBM_READER()) {
                    293: # We are reading
                    294:            if (!open($sym,"$file_prefix.db.lock")) {
                    295: # We don't have a lock file. This could mean
                    296: # - that there is no such db-file
                    297: # - that it does not have a lock file yet
                    298:                if ((! -e "$file_prefix.db") && (! -e "$file_prefix.db.gz")) {
                    299: # No such file. Forget it.                
                    300:                    $! = 2;
1.11      albertel  301: 		   &clean_sym();
1.2       www       302:                    return undef;
                    303:                }
                    304: # Apparently just no lock file yet. Make one
                    305:                open($sym,">>$file_prefix.db.lock");
                    306:            }
                    307: # Do a shared lock
1.9       albertel  308:            if (!&flock_sym(LOCK_SH)) { 
1.11      albertel  309: 	       &clean_sym();
1.9       albertel  310: 	       return undef; 
                    311: 	   } 
1.2       www       312: # If this is compressed, we will actually need an exclusive lock
                    313: 	   if (-e "$file_prefix.db.gz") {
1.9       albertel  314: 	       if (!&flock_sym(LOCK_EX)) {
1.11      albertel  315: 		   &clean_sym();
1.9       albertel  316: 		   return undef;
                    317: 	       }
1.2       www       318: 	   }
                    319:         } elsif ($how eq &GDBM_WRCREAT()) {
                    320: # We are writing
                    321:            open($sym,">>$file_prefix.db.lock");
                    322: # Writing needs exclusive lock
1.9       albertel  323:            if (!&flock_sym(LOCK_EX)) {
1.11      albertel  324: 	       &clean_sym();
1.9       albertel  325: 	       return undef;
                    326: 	   }
1.2       www       327:         } else {
1.5       albertel  328:            die("Unknown method $how for $file_prefix");
1.2       www       329:         }
                    330: # The file is ours!
                    331: # If it is archived, un-archive it now
                    332:        if (-e "$file_prefix.db.gz") {
                    333:            system("gunzip $file_prefix.db.gz");
                    334: 	   if (-e "$file_prefix.hist.gz") {
                    335: 	       system("gunzip $file_prefix.hist.gz");
                    336: 	   }
                    337:        }
                    338: # Change access mode to non-blocking
                    339:        $how=$how|&GDBM_NOLOCK();
                    340: # Go ahead and tie the hash
1.13      albertel  341:       	my $result = 
                    342: 	    &_do_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
                    343: 	if (!$result) {
                    344: 	    &clean_sym();
                    345: 	}
                    346: 	return $result;
1.2       www       347:     }
                    348: 
                    349:     sub flock_sym {
                    350:         my ($lock_type)=@_;
                    351: 	my $failed=0;
                    352: 	eval {
                    353: 	    local $SIG{__DIE__}='DEFAULT';
                    354: 	    local $SIG{ALRM}=sub {
                    355: 		$failed=1;
                    356: 		die("failed lock");
                    357: 	    };
                    358: 	    alarm($loncapa_max_wait_time);
                    359: 	    flock($sym,$lock_type);
                    360: 	    alarm(0);
                    361: 	};
                    362: 	if ($failed) {
                    363: 	    $! = 100; # throwing error # 100
                    364: 	    return undef;
                    365: 	} else {
                    366: 	    return 1;
                    367: 	}
                    368:     }
                    369: 
                    370:     sub _locking_hash_untie {
                    371: 	my ($hashref) = @_;
                    372: 	my $result = untie(%$hashref);
                    373: 	flock($sym,LOCK_UN);
                    374: 	close($sym);
1.11      albertel  375: 	&clean_sym();
1.2       www       376: 	return $result;
                    377:     }
                    378: }
                    379: 
                    380: BEGIN {
1.4       albertel  381:     %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
1.2       www       382: }
                    383: 
1.1       albertel  384: 1;
                    385: 
                    386: __END__
                    387: 
                    388: 
1.27    ! jms       389: =head1 NAME
        !           390: 
        !           391: Apache::LONCAPA
        !           392: 
        !           393: LONCAPA - Basic routines
        !           394: 
        !           395: =head1 SYNOPSIS
        !           396: 
        !           397: Generally useful routines
        !           398: 
        !           399: =head1 EXPORTED SUBROUTINES
        !           400: 
        !           401: =over
        !           402: 
        !           403: =item escape()
        !           404: 
        !           405: unpack non-word characters into CGI-compatible hex codes
        !           406: 
        !           407: =item unescape()
        !           408: 
        !           409:  pack CGI-compatible hex codes into actual non-word ASCII character
        !           410: 
        !           411: =item  add_get_param()
        !           412:  
        !           413:  Inputs:  url (with or without exit GET from parameters), hash ref of
        !           414:               form name => value pairs
        !           415: 
        !           416:  Return: url with properly added the form name elements and values to the 
        !           417:          the url doing proper escaping of the values and joining with ? or &
        !           418:          as needed
        !           419: 
        !           420: =item clean_handle()
        !           421: 
        !           422: =item propath()
        !           423: 
        !           424: =item untie_domain_hash()
        !           425: 
        !           426: =item tie_domain_hash()
        !           427: 
        !           428: Manipulation of hash based databases (factoring out common code
        !           429: for later use as we refactor.
        !           430: 
        !           431:  Ties a domain level resource file to a hash.
        !           432:  If requested a history entry is created in the associated hist file.
        !           433: 
        !           434:  Parameters:
        !           435:     domain    - Name of the domain in which the resource file lives.
        !           436:     namespace - Name of the hash within that domain.
        !           437:     how       - How to tie the hash (e.g. GDBM_WRCREAT()).
        !           438:     loghead   - Optional parameter, if present a log entry is created
        !           439:                 in the associated history file and this is the first part
        !           440:                  of that entry.
        !           441:     logtail   - Goes along with loghead,  The actual logentry is of the
        !           442:                 form $loghead:<timestamp>:logtail.
        !           443: Returns:
        !           444:    Reference to a hash bound to the db file or alternatively undef
        !           445:    if the tie failed.
        !           446: 
        !           447: =item tie_user_hash()
        !           448: 
        !           449:   Ties a user's resource file to a hash.  
        !           450:   If necessary, an appropriate history
        !           451:   log file entry is made as well.
        !           452:   This sub factors out common code from the subs that manipulate
        !           453:   the various gdbm files that keep keyword value pairs.
        !           454: Parameters:
        !           455:   domain       - Name of the domain the user is in.
        !           456:   user         - Name of the 'current user'.
        !           457:   namespace    - Namespace representing the file to tie.
        !           458:   how          - What the tie is done to (e.g. GDBM_WRCREAT().
        !           459:   loghead      - Optional first part of log entry if there may be a
        !           460:                  history file.
        !           461:   what         - Optional tail of log entry if there may be a history
        !           462:                  file.
        !           463: Returns:
        !           464:   hash to which the database is tied.  It's up to the caller to untie.
        !           465:   undef if the has could not be tied.
        !           466: 
        !           467: =item locking_hash_tie()
        !           468: 
        !           469: routines if you just have a filename return tied hashref or undef
        !           470: 
        !           471: =item locking_hash_untie()
        !           472: 
        !           473: =item db_filename_parts()
        !           474: 
        !           475: =head1 INTERNAL SUBROUTINES
        !           476: 
        !           477: =item _do_hash_tie()
        !           478: 
        !           479: =item _do_hash_untie()
        !           480: 
        !           481: =back
        !           482: 
        !           483: =cut
        !           484: 

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