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 1.43 2002/05/17 14:03:04 matthew 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: # YEAR=2000
31: # lonsql-based on the preforker:harsha jagasia:date:5/10/00
32: # 7/25 Gerd Kortemeyer
33: # many different dates Scott Harrison
34: # YEAR=2001
35: # many different dates Scott Harrison
36: # 03/22/2001 Scott Harrison
37: # 8/30 Gerd Kortemeyer
38: # 10/17,11/28,11/29,12/20 Scott Harrison
39: # YEAR=2001
40: # 5/11 Scott Harrison
41: #
42: ###
43:
44: ###############################################################################
45: ## ##
46: ## ORGANIZATION OF THIS PERL SCRIPT ##
47: ## 1. Modules used ##
48: ## 2. Enable find subroutine ##
49: ## 3. Read httpd config files and get variables ##
50: ## 4. Make sure that database can be accessed ##
51: ## 5. Make sure this process is running from user=www ##
52: ## 6. Check if other instance is running ##
53: ## 7. POD (plain old documentation, CPAN style) ##
54: ## ##
55: ###############################################################################
56:
57: use lib '/home/httpd/lib/perl/';
58: use LONCAPA::Configuration;
59:
60: use IO::Socket;
61: use Symbol;
62: use POSIX;
63: use IO::Select;
64: use IO::File;
65: use Socket;
66: use Fcntl;
67: use Tie::RefHash;
68: use DBI;
69:
70: my @metalist;
71: # ----------------- Code to enable 'find' subroutine listing of the .meta files
72: require "find.pl";
73: sub wanted {
74: (($dev,$ino,$mode,$nlink,$uid,$gid) = lstat($_)) &&
75: -f _ &&
76: /^.*\.meta$/ && !/^.+\.\d+\.[^\.]+\.meta$/ &&
77: push(@metalist,"$dir/$_");
78: }
79:
80: $childmaxattempts=10;
81: $run =0;#running counter to generate the query-id
82:
83: # -------------------------------- Read loncapa_apache.conf and loncapa.conf
84: my $perlvarref=LONCAPA::Configuration::read_conf('loncapa_apache.conf',
85: 'loncapa.conf');
86: my %perlvar=%{$perlvarref};
87:
88: # ------------------------------------- Make sure that database can be accessed
89: {
90: my $dbh;
91: unless (
92: $dbh = DBI->connect("DBI:mysql:loncapa","www",$perlvar{'lonSqlAccess'},{ RaiseError =>0,PrintError=>0})
93: ) {
94: print "Cannot connect to database!\n";
95: $emailto="$perlvar{'lonAdmEMail'},$perlvar{'lonSysEMail'}";
96: $subj="LON: $perlvar{'lonHostID'} Cannot connect to database!";
97: system("echo 'Cannot connect to MySQL database!' |\
98: mailto $emailto -s '$subj' > /dev/null");
99: exit 1;
100: }
101: else {
102: $dbh->disconnect;
103: }
104: }
105:
106: # --------------------------------------------- Check if other instance running
107:
108: my $pidfile="$perlvar{'lonDaemons'}/logs/lonsql.pid";
109:
110: if (-e $pidfile) {
111: my $lfh=IO::File->new("$pidfile");
112: my $pide=<$lfh>;
113: chomp($pide);
114: if (kill 0 => $pide) { die "already running"; }
115: }
116:
117: # ------------------------------------------------------------- Read hosts file
118: $PREFORK=4; # number of children to maintain, at least four spare
119:
120: open (CONFIG,"$perlvar{'lonTabDir'}/hosts.tab") || die "Can't read host file";
121:
122: while ($configline=<CONFIG>) {
123: my ($id,$domain,$role,$name,$ip)=split(/:/,$configline);
124: chomp($ip);
125:
126: $hostip{$ip}=$id;
127: if ($id eq $perlvar{'lonHostID'}) { $thisserver=$name; }
128:
129: $PREFORK++;
130: }
131: close(CONFIG);
132:
133: $PREFORK=int($PREFORK/4);
134:
135: $unixsock = "mysqlsock";
136: my $localfile="$perlvar{'lonSockDir'}/$unixsock";
137: my $server;
138: unlink ($localfile);
139: unless ($server=IO::Socket::UNIX->new(Local =>"$localfile",
140: Type => SOCK_STREAM,
141: Listen => 10))
142: {
143: print "in socket error:$@\n";
144: }
145:
146: # -------------------------------------------------------- Routines for forking
147: # global variables
148: $MAX_CLIENTS_PER_CHILD = 5; # number of clients each child should process
149: %children = (); # keys are current child process IDs
150: $children = 0; # current number of children
151:
152: sub REAPER { # takes care of dead children
153: $SIG{CHLD} = \&REAPER;
154: my $pid = wait;
155: $children --;
156: &logthis("Child $pid died");
157: delete $children{$pid};
158: }
159:
160: sub HUNTSMAN { # signal handler for SIGINT
161: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
162: kill 'INT' => keys %children;
163: my $execdir=$perlvar{'lonDaemons'};
164: unlink("$execdir/logs/lonsql.pid");
165: &logthis("<font color=red>CRITICAL: Shutting down</font>");
166: $unixsock = "mysqlsock";
167: my $port="$perlvar{'lonSockDir'}/$unixsock";
168: unlink(port);
169: exit; # clean up with dignity
170: }
171:
172: sub HUPSMAN { # signal handler for SIGHUP
173: local($SIG{CHLD}) = 'IGNORE'; # we're going to kill our children
174: kill 'INT' => keys %children;
175: close($server); # free up socket
176: &logthis("<font color=red>CRITICAL: Restarting</font>");
177: my $execdir=$perlvar{'lonDaemons'};
178: $unixsock = "mysqlsock";
179: my $port="$perlvar{'lonSockDir'}/$unixsock";
180: unlink(port);
181: exec("$execdir/lonsql"); # here we go again
182: }
183:
184: sub logthis {
185: my $message=shift;
186: my $execdir=$perlvar{'lonDaemons'};
187: my $fh=IO::File->new(">>$execdir/logs/lonsqlfinal.log");
188: my $now=time;
189: my $local=localtime($now);
190: print $fh "$local ($$): $message\n";
191: }
192: # ---------------------------------------------------- Fork once and dissociate
193: $fpid=fork;
194: exit if $fpid;
195: die "Couldn't fork: $!" unless defined ($fpid);
196:
197: POSIX::setsid() or die "Can't start new session: $!";
198:
199: # ------------------------------------------------------- Write our PID on disk
200:
201: $execdir=$perlvar{'lonDaemons'};
202: open (PIDSAVE,">$execdir/logs/lonsql.pid");
203: print PIDSAVE "$$\n";
204: close(PIDSAVE);
205: &logthis("<font color=red>CRITICAL: ---------- Starting ----------</font>");
206:
207: # ----------------------------- Ignore signals generated during initial startup
208: $SIG{HUP}=$SIG{USR1}='IGNORE';
209: # ------------------------------------------------------- Now we are on our own
210: # Fork off our children.
211: for (1 .. $PREFORK) {
212: make_new_child();
213: }
214:
215: # Install signal handlers.
216: $SIG{CHLD} = \&REAPER;
217: $SIG{INT} = $SIG{TERM} = \&HUNTSMAN;
218: $SIG{HUP} = \&HUPSMAN;
219:
220: # And maintain the population.
221: while (1) {
222: sleep; # wait for a signal (i.e., child's death)
223: for ($i = $children; $i < $PREFORK; $i++) {
224: make_new_child(); # top up the child pool
225: }
226: }
227:
228:
229: sub make_new_child {
230: my $pid;
231: my $sigset;
232:
233: # block signal for fork
234: $sigset = POSIX::SigSet->new(SIGINT);
235: sigprocmask(SIG_BLOCK, $sigset)
236: or die "Can't block SIGINT for fork: $!\n";
237:
238: die "fork: $!" unless defined ($pid = fork);
239:
240: if ($pid) {
241: # Parent records the child's birth and returns.
242: sigprocmask(SIG_UNBLOCK, $sigset)
243: or die "Can't unblock SIGINT for fork: $!\n";
244: $children{$pid} = 1;
245: $children++;
246: return;
247: } else {
248: # Child can *not* return from this subroutine.
249: $SIG{INT} = 'DEFAULT'; # make SIGINT kill us as it did before
250:
251: # unblock signals
252: sigprocmask(SIG_UNBLOCK, $sigset)
253: or die "Can't unblock SIGINT for fork: $!\n";
254:
255:
256: #open database handle
257: # making dbh global to avoid garbage collector
258: unless (
259: $dbh = DBI->connect("DBI:mysql:loncapa","www",$perlvar{'lonSqlAccess'},{ RaiseError =>0,PrintError=>0})
260: ) {
261: sleep(10+int(rand(20)));
262: &logthis("<font color=blue>WARNING: Couldn't connect to database ($st secs): $@</font>");
263: print "database handle error\n";
264: exit;
265:
266: };
267: # make sure that a database disconnection occurs with ending kill signals
268: $SIG{TERM}=$SIG{INT}=$SIG{QUIT}=$SIG{__DIE__}=\&DISCONNECT;
269:
270: # handle connections until we've reached $MAX_CLIENTS_PER_CHILD
271: for ($i=0; $i < $MAX_CLIENTS_PER_CHILD; $i++) {
272: $client = $server->accept() or last;
273:
274: # do something with the connection
275: $run = $run+1;
276: my $userinput = <$client>;
277: chomp($userinput);
278:
279: my ($conserver,$querytmp,
280: $customtmp,$customshowtmp)=split(/&/,$userinput);
281: my $query=unescape($querytmp);
282: my $custom=unescape($customtmp);
283: my $customshow=unescape($customshowtmp);
284:
285: #send query id which is pid_unixdatetime_runningcounter
286: $queryid = $thisserver;
287: $queryid .="_".($$)."_";
288: $queryid .= time."_";
289: $queryid .= $run;
290: print $client "$queryid\n";
291:
292: &logthis("QUERY: $query");
293: &logthis("QUERY: $query");
294: sleep 1;
295: #prepare and execute the query
296: my $sth = $dbh->prepare($query);
297: my $result;
298: my @files;
299: my $subsetflag=0;
300: if ($query) {
301: unless ($sth->execute())
302: {
303: &logthis("<font color=blue>WARNING: Could not retrieve from database: $@</font>");
304: $result="";
305: }
306: else {
307: my $r1=$sth->fetchall_arrayref;
308: my @r2;
309: foreach (@$r1) {my $a=$_;
310: my @b=map {escape($_)} @$a;
311: push @files,@{$a}[3];
312: push @r2,join(",", @b)
313: }
314: $result=join("&",@r2);
315: }
316: }
317: # do custom metadata searching here and build into result
318: if ($custom or $customshow) {
319: &logthis("am going to do custom query for $custom");
320: if ($query) {
321: @metalist=map {$perlvar{'lonDocRoot'}.$_.'.meta'} @files;
322: }
323: else {
324: @metalist=(); pop @metalist;
325: opendir(RESOURCES,"$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}");
326: my @homeusers=grep
327: {&ishome("$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}/$_")}
328: grep {!/^\.\.?$/} readdir(RESOURCES);
329: closedir RESOURCES;
330: foreach my $user (@homeusers) {
331: &find("$perlvar{'lonDocRoot'}/res/$perlvar{'lonDefDomain'}/$user");
332: }
333: }
334: # &logthis("FILELIST:" . join(":::",@metalist));
335: # if file is indicated in sql database and
336: # not part of sql-relevant query, do not pattern match.
337: # if file is not in sql database, output error.
338: # if file is indicated in sql database and is
339: # part of query result list, then do the pattern match.
340: my $customresult='';
341: my @r2;
342: foreach my $m (@metalist) {
343: my $fh=IO::File->new($m);
344: my @lines=<$fh>;
345: my $stuff=join('',@lines);
346: if ($stuff=~/$custom/s) {
347: foreach my $f ('abstract','author','copyright',
348: 'creationdate','keywords','language',
349: 'lastrevisiondate','mime','notes',
350: 'owner','subject','title') {
351: $stuff=~s/\n?\<$f[^\>]*\>.*?<\/$f[^\>]*\>\n?//s;
352: }
353: my $m2=$m; my $docroot=$perlvar{'lonDocRoot'};
354: $m2=~s/^$docroot//;
355: $m2=~s/\.meta$//;
356: unless ($query) {
357: my $q2="select * from metadata where url like binary '$m2'";
358: my $sth = $dbh->prepare($q2);
359: $sth->execute();
360: my $r1=$sth->fetchall_arrayref;
361: foreach (@$r1) {my $a=$_;
362: my @b=map {escape($_)} @$a;
363: push @files,@{$a}[3];
364: push @r2,join(",", @b)
365: }
366: }
367: # &logthis("found: $stuff");
368: $customresult.='&custom='.escape($m2).','.escape($stuff);
369: }
370: }
371: $result=join("&",@r2) unless $query;
372: $result.=$customresult;
373: }
374: # reply with result
375: $result.="\n" if $result;
376: &reply("queryreply:$queryid:$result",$conserver);
377:
378: }
379:
380: # tidy up gracefully and finish
381:
382: #close the database handle
383: $dbh->disconnect
384: or &logthis("<font color=blue>WARNING: Couldn't disconnect from database $DBI::errstr ($st secs): $@</font>");
385:
386: # this exit is VERY important, otherwise the child will become
387: # a producer of more and more children, forking yourself into
388: # process death.
389: exit;
390: }
391: }
392:
393: sub DISCONNECT {
394: $dbh->disconnect or
395: &logthis("<font color=blue>WARNING: Couldn't disconnect from database $DBI::errstr ($st secs): $@</font>");
396: exit;
397: }
398:
399: # -------------------------------------------------- Non-critical communication
400:
401: sub subreply {
402: my ($cmd,$server)=@_;
403: my $peerfile="$perlvar{'lonSockDir'}/$server";
404: my $sclient=IO::Socket::UNIX->new(Peer =>"$peerfile",
405: Type => SOCK_STREAM,
406: Timeout => 10)
407: or return "con_lost";
408: print $sclient "$cmd\n";
409: my $answer=<$sclient>;
410: chomp($answer);
411: if (!$answer) { $answer="con_lost"; }
412: return $answer;
413: }
414:
415: sub reply {
416: my ($cmd,$server)=@_;
417: my $answer;
418: if ($server ne $perlvar{'lonHostID'}) {
419: $answer=subreply($cmd,$server);
420: if ($answer eq 'con_lost') {
421: $answer=subreply("ping",$server);
422: $answer=subreply($cmd,$server);
423: }
424: } else {
425: $answer='self_reply';
426: $answer=subreply($cmd,$server);
427: }
428: return $answer;
429: }
430:
431: # -------------------------------------------------------- Escape Special Chars
432:
433: sub escape {
434: my $str=shift;
435: $str =~ s/(\W)/"%".unpack('H2',$1)/eg;
436: return $str;
437: }
438:
439: # ----------------------------------------------------- Un-Escape Special Chars
440:
441: sub unescape {
442: my $str=shift;
443: $str =~ s/%([a-fA-F0-9][a-fA-F0-9])/pack("C",hex($1))/eg;
444: return $str;
445: }
446:
447: # --------------------------------------- Is this the home server of an author?
448: # (copied from lond, modification of the return value)
449: sub ishome {
450: my $author=shift;
451: $author=~s/\/home\/httpd\/html\/res\/([^\/]*)\/([^\/]*).*/$1\/$2/;
452: my ($udom,$uname)=split(/\//,$author);
453: my $proname=propath($udom,$uname);
454: if (-e $proname) {
455: return 1;
456: } else {
457: return 0;
458: }
459: }
460:
461: # -------------------------------------------- Return path to profile directory
462: # (copied from lond)
463: sub propath {
464: my ($udom,$uname)=@_;
465: $udom=~s/\W//g;
466: $uname=~s/\W//g;
467: my $subdir=$uname.'__';
468: $subdir =~ s/(.)(.)(.).*/$1\/$2\/$3/;
469: my $proname="$perlvar{'lonUsersDir'}/$udom/$subdir/$uname";
470: return $proname;
471: }
472:
473: # ----------------------------------- POD (plain old documentation, CPAN style)
474:
475: =head1 NAME
476:
477: lonsql - LON TCP-MySQL-Server Daemon for handling database requests.
478:
479: =head1 SYNOPSIS
480:
481: This script should be run as user=www. The following is an example invocation
482: from the loncron script. Note that a lonsql.pid file contains the pid of
483: the parent process.
484:
485: if (-e $lonsqlfile) {
486: my $lfh=IO::File->new("$lonsqlfile");
487: my $lonsqlpid=<$lfh>;
488: chomp($lonsqlpid);
489: if (kill 0 => $lonsqlpid) {
490: print $fh "<h3>lonsql at pid $lonsqlpid responding</h3>";
491: $restartflag=0;
492: } else {
493: $errors++; $errors++;
494: print $fh "<h3>lonsql at pid $lonsqlpid not responding</h3>";
495: $restartflag=1;
496: print $fh
497: "<h3>Decided to clean up stale .pid file and restart lonsql</h3>";
498: }
499: }
500: if ($restartflag==1) {
501: $errors++;
502: print $fh '<br><font color="red">Killall lonsql: '.
503: system('killall lonsql').' - ';
504: sleep 60;
505: print $fh unlink($lonsqlfile).' - '.
506: system('killall -9 lonsql').
507: '</font><br>';
508: print $fh "<h3>lonsql not running, trying to start</h3>";
509: system(
510: "$perlvar{'lonDaemons'}/lonsql 2>>$perlvar{'lonDaemons'}/logs/lonsql_errors");
511: sleep 10;
512:
513: =head1 DESCRIPTION
514:
515: Not yet written.
516:
517: =head1 README
518:
519: Not yet written.
520:
521: =head1 PREREQUISITES
522:
523: IO::Socket
524: Symbol
525: POSIX
526: IO::Select
527: IO::File
528: Socket
529: Fcntl
530: Tie::RefHash
531: DBI
532:
533: =head1 COREQUISITES
534:
535: =head1 OSNAMES
536:
537: linux
538:
539: =head1 SCRIPT CATEGORIES
540:
541: Server/Process
542:
543: =cut
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