1: # The LearningOnline Network
2: # Base routines
3: #
4: # $Id: LONCAPA.pm,v 1.21 2006/12/10 23:06:13 albertel Exp $
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:
30: package LONCAPA;
31:
32: use strict;
33: use lib '/home/httpd/lib/perl/';
34: use LONCAPA::Configuration;
35: use Fcntl qw(:flock);
36: use GDBM_File;
37: use POSIX;
38:
39: my $loncapa_max_wait_time = 13;
40:
41:
42: use vars qw($match_domain $match_not_domain
43: $match_username $match_not_username
44: $match_courseid $match_not_courseid
45: $match_name
46: $match_handle $match_not_handle);
47:
48: require Exporter;
49: our @ISA = qw (Exporter);
50: our @EXPORT = qw(&add_get_param &escape &unescape
51: &tie_domain_hash &untie_domain_hash &tie_user_hash
52: &untie_user_hash &propath);
53: our @EXPORT_OK = qw($match_domain $match_not_domain
54: $match_username $match_not_username
55: $match_courseid $match_not_courseid
56: $match_name
57: $match_handle $match_not_handle);
58: our %EXPORT_TAGS = ( 'match' =>[qw($match_domain $match_not_domain
59: $match_username $match_not_username
60: $match_courseid $match_not_courseid
61: $match_name
62: $match_handle $match_not_handle)],);
63: my %perlvar;
64:
65:
66:
67: # Inputs are a url, and a hash ref of
68: # form name => value pairs
69: # takes care of properly adding the form name elements and values to the
70: # the url doing proper escaping of the values and joining with ? or & as
71: # needed
72:
73: sub add_get_param {
74: my ($url,$form_data) = @_;
75: my $needs_question_mark = ($url !~ /\?/);
76:
77: while (my ($name,$value) = each(%$form_data)) {
78: if ($needs_question_mark) {
79: $url.='?';
80: $needs_question_mark = 0;
81: } else {
82: $url.='&';
83: }
84: $url.=$name.'='.&escape($form_data->{$name});
85: }
86: return $url;
87: }
88:
89: # -------------------------------------------------------- Escape Special Chars
90:
91: sub escape {
92: my $str=shift;
93: $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
94: return $str;
95: }
96:
97: # ----------------------------------------------------- Un-Escape Special Chars
98:
99: sub unescape {
100: my $str=shift;
101: $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
102: return $str;
103: }
104:
105: $match_domain = $LONCAPA::domain_re = qr{[\w\-.]+};
106: $match_not_domain = $LONCAPA::not_domain_re = qr{[^\w\-.]+};
107: sub clean_domain {
108: my ($domain) = @_;
109: $domain =~ s/$match_not_domain//g;
110: return $domain;
111: }
112:
113: $match_username = $LONCAPA::username_re = qr{\w[\w\-.]+};
114: $match_not_username = $LONCAPA::not_username_re = qr{[^\w\-.]+};
115: sub clean_username {
116: my ($username) = @_;
117: $username =~ s/^\W+//;
118: $username =~ s/$match_not_username//g;
119: return $username;
120: }
121:
122:
123: $match_courseid = $LONCAPA::courseid_re = qr{\d[\w\-.]+};
124: $match_not_courseid = $LONCAPA::not_courseid_re = qr{[^\w\-.]+};
125:
126: $match_name = $LONCAPA::name = qr{$match_username|$match_courseid};
127: sub clean_name {
128: my ($name) = @_;
129: $name =~ s/$match_not_username//g;
130: return $name;
131: }
132:
133: sub split_courseid {
134: my ($courseid) = @_;
135: my ($domain,$coursenum) =
136: ($courseid=~m{^/($match_domain)/($match_courseid)});
137: return ($domain,$coursenum);
138: }
139:
140: $match_handle = $LONCAPA::handle_re = qr{[\w\-.]+};
141: $match_not_handle = $LONCAPA::not_handle_re = qr{[^\w\-.]+};
142: sub clean_handle {
143: my ($handle) = @_;
144: $handle =~ s/$match_not_handle//g;
145: return $handle;
146: }
147:
148: # -------------------------------------------- Return path to profile directory
149:
150: sub propath {
151: my ($udom,$uname)=@_;
152: $udom = &clean_domain($udom);
153: $uname= &clean_name($uname);
154: my $subdir=$uname.'__';
155: $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
156: my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
157: return $proname;
158: }
159:
160:
161: #---------------------------------------------------------------
162: #
163: # Manipulation of hash based databases (factoring out common code
164: # for later use as we refactor.
165: #
166: # Ties a domain level resource file to a hash.
167: # If requested a history entry is created in the associated hist file.
168: #
169: # Parameters:
170: # domain - Name of the domain in which the resource file lives.
171: # namespace - Name of the hash within that domain.
172: # how - How to tie the hash (e.g. GDBM_WRCREAT()).
173: # loghead - Optional parameter, if present a log entry is created
174: # in the associated history file and this is the first part
175: # of that entry.
176: # logtail - Goes along with loghead, The actual logentry is of the
177: # form $loghead:<timestamp>:logtail.
178: # Returns:
179: # Reference to a hash bound to the db file or alternatively undef
180: # if the tie failed.
181: #
182: sub tie_domain_hash {
183: my ($domain,$namespace,$how,$loghead,$logtail) = @_;
184:
185: # Filter out any whitespace in the domain name:
186:
187: $domain = &clean_domain($domain);
188:
189: # We have enough to go on to tie the hash:
190:
191: my $user_top_dir = $perlvar{'lonUsersDir'};
192: my $domain_dir = $user_top_dir."/$domain";
193: my $resource_file = $domain_dir."/$namespace";
194: return &_locking_hash_tie($resource_file,$namespace,$how,$loghead,$logtail);
195: }
196:
197: sub untie_domain_hash {
198: return &_locking_hash_untie(@_);
199: }
200: #
201: # Ties a user's resource file to a hash.
202: # If necessary, an appropriate history
203: # log file entry is made as well.
204: # This sub factors out common code from the subs that manipulate
205: # the various gdbm files that keep keyword value pairs.
206: # Parameters:
207: # domain - Name of the domain the user is in.
208: # user - Name of the 'current user'.
209: # namespace - Namespace representing the file to tie.
210: # how - What the tie is done to (e.g. GDBM_WRCREAT().
211: # loghead - Optional first part of log entry if there may be a
212: # history file.
213: # what - Optional tail of log entry if there may be a history
214: # file.
215: # Returns:
216: # hash to which the database is tied. It's up to the caller to untie.
217: # undef if the has could not be tied.
218: #
219: sub tie_user_hash {
220: my ($domain,$user,$namespace,$how,$loghead,$what) = @_;
221:
222: $namespace=~s{/}{_}g; # / -> _
223: $namespace = &clean_username($namespace);
224: my $proname = &propath($domain, $user);
225: my $file_prefix="$proname/$namespace";
226: return &_locking_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
227: }
228:
229: sub untie_user_hash {
230: return &_locking_hash_untie(@_);
231: }
232:
233: # routines if you just have a filename
234: # return tied hashref or undef
235:
236: sub locking_hash_tie {
237: my ($filename,$how)=@_;
238: my ($file_prefix,$namespace)=&db_filename_parts($filename);
239: if ($namespace eq '') { return undef; }
240: return &_locking_hash_tie($file_prefix,$namespace,$how);
241: }
242:
243: sub locking_hash_untie {
244: return &_locking_hash_untie(@_);
245: }
246:
247: sub db_filename_parts {
248: my ($filename)=@_;
249: my ($file_path,$namespace)=($filename=~/^(.*)\/([^\/]+)\.db$/);
250: if ($namespace eq '') { return undef; }
251: return ($file_path.'/'.$namespace,$namespace);
252: }
253:
254: # internal routines that handle the actual tieing and untieing process
255:
256: sub _do_hash_tie {
257: my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
258: my %hash;
259: if(tie(%hash, 'GDBM_File', "$file_prefix.db", $how, 0640)) {
260: # If this is a namespace for which a history is kept,
261: # make the history log entry:
262: if (($namespace !~/^nohist\_/) && (defined($loghead))) {
263: my $hfh = IO::File->new(">>$file_prefix.hist");
264: if($hfh) {
265: my $now = time();
266: print $hfh ("$loghead:$now:$what\n");
267: }
268: $hfh->close;
269: }
270: return \%hash;
271: } else {
272: return undef;
273: }
274: }
275:
276: sub _do_hash_untie {
277: my ($hashref) = @_;
278: my $result = untie(%$hashref);
279: return $result;
280: }
281:
282: {
283: my $sym;
284: my @pushed_syms;
285:
286: sub clean_sym {
287: undef($sym);
288: }
289: sub push_locking_hash_tie {
290: if (!defined($sym)) {
291: die("Invalid used of push_locking_hash_tie, should only be called after a lock has occurred and before and unlock.");
292: }
293: push(@pushed_syms,$sym);
294: undef($sym);
295: }
296:
297: sub pop_locking_hash_tie {
298: if (defined($sym)) {
299: die("Invalid nested used of pop_locking_hash_tie, should only be called after a unlock has occurred.");
300: }
301: $sym = pop(@pushed_syms);
302: }
303:
304: sub _locking_hash_tie {
305: my ($file_prefix,$namespace,$how,$loghead,$what) = @_;
306: if (defined($sym)) {
307: die('Nested locking attempted without proper use of push_locking_hash_tie, this is unsupported');
308: }
309:
310: my $lock_type=LOCK_SH;
311: # Are we reading or writing?
312: if ($how eq &GDBM_READER()) {
313: # We are reading
314: if (!open($sym,"$file_prefix.db.lock")) {
315: # We don't have a lock file. This could mean
316: # - that there is no such db-file
317: # - that it does not have a lock file yet
318: if ((! -e "$file_prefix.db") && (! -e "$file_prefix.db.gz")) {
319: # No such file. Forget it.
320: $! = 2;
321: &clean_sym();
322: return undef;
323: }
324: # Apparently just no lock file yet. Make one
325: open($sym,">>$file_prefix.db.lock");
326: }
327: # Do a shared lock
328: if (!&flock_sym(LOCK_SH)) {
329: &clean_sym();
330: return undef;
331: }
332: # If this is compressed, we will actually need an exclusive lock
333: if (-e "$file_prefix.db.gz") {
334: if (!&flock_sym(LOCK_EX)) {
335: &clean_sym();
336: return undef;
337: }
338: }
339: } elsif ($how eq &GDBM_WRCREAT()) {
340: # We are writing
341: open($sym,">>$file_prefix.db.lock");
342: # Writing needs exclusive lock
343: if (!&flock_sym(LOCK_EX)) {
344: &clean_sym();
345: return undef;
346: }
347: } else {
348: die("Unknown method $how for $file_prefix");
349: }
350: # The file is ours!
351: # If it is archived, un-archive it now
352: if (-e "$file_prefix.db.gz") {
353: system("gunzip $file_prefix.db.gz");
354: if (-e "$file_prefix.hist.gz") {
355: system("gunzip $file_prefix.hist.gz");
356: }
357: }
358: # Change access mode to non-blocking
359: $how=$how|&GDBM_NOLOCK();
360: # Go ahead and tie the hash
361: my $result =
362: &_do_hash_tie($file_prefix,$namespace,$how,$loghead,$what);
363: if (!$result) {
364: &clean_sym();
365: }
366: return $result;
367: }
368:
369: sub flock_sym {
370: my ($lock_type)=@_;
371: my $failed=0;
372: eval {
373: local $SIG{__DIE__}='DEFAULT';
374: local $SIG{ALRM}=sub {
375: $failed=1;
376: die("failed lock");
377: };
378: alarm($loncapa_max_wait_time);
379: flock($sym,$lock_type);
380: alarm(0);
381: };
382: if ($failed) {
383: $! = 100; # throwing error # 100
384: return undef;
385: } else {
386: return 1;
387: }
388: }
389:
390: sub _locking_hash_untie {
391: my ($hashref) = @_;
392: my $result = untie(%$hashref);
393: flock($sym,LOCK_UN);
394: close($sym);
395: &clean_sym();
396: return $result;
397: }
398: }
399:
400: BEGIN {
401: %perlvar=%{&LONCAPA::Configuration::read_conf('loncapa.conf')};
402: }
403:
404: 1;
405:
406: __END__
407:
408: =pod
409:
410: =head1 NAME
411:
412: LONCAPA - Basic routines
413:
414: =head1 SYNOPSIS
415:
416: Generally useful routines
417:
418: =head1 EXPORTED SUBROUTINES
419:
420: =over 4
421:
422: =item *
423:
424: escape() : unpack non-word characters into CGI-compatible hex codes
425:
426: =item *
427:
428: unescape() : pack CGI-compatible hex codes into actual non-word ASCII character
429:
430: =item *
431:
432: add_get_param() :
433: Inputs: url (with or without exit GET from parameters), hash ref of
434: form name => value pairs
435:
436: Return: url with properly added the form name elements and values to the
437: the url doing proper escaping of the values and joining with ? or &
438: as needed
439:
440: =back
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