1: #!/usr/bin/perl
2: # The LearningOnline Network with CAPA
3: # Push admin files from cluster manager to cluster's "name servers".
4: #
5: # $Id: clusteradmin,v 1.7 2018/08/20 22:31:49 raeburn Exp $
6: #
7: # Copyright Michigan State University Board of Trustees
8: #
9: # This file is part of the LearningOnline Network with CAPA (LON-CAPA).
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: =pod
29:
30: =head1 SYNOPSIS
31:
32: clusteradmin command [args]
33:
34: =head1 DESCRIPTION
35:
36: Performs an adminstrative update on (a) "DNS" hosts or domains in the current
37: dns_hosts.tab or dns_domain.tab files, or (b) update of the Certificate
38: Revocation List (CRL) file for the cluster.
39:
40: For this to work, the current host must be the cluster administrator
41: on the target systems. That is this must be a host in managers.tab.
42: Furthermore, lonc must be running on this system.
43:
44: The action is specified by the 'command' parameter which may have additional arguments.
45:
46: All communications with remote clients are made critical so that
47: they will eventually happen even if the host we want to talk with
48: is dead.
49:
50:
51: =head1 ACTIONS
52:
53: =over 3
54:
55: =item help
56:
57: Outputs a brief description of the actions supported and what they do.
58:
59: =item update file
60:
61: Update the contents of an administrative file with the contents of that file
62: on this system. 'file' is the name of that file, not the path for example:
63:
64: clusteradmin update dns_hosts.tab
65:
66: =back
67:
68: =head1 ASSUMPTIONS
69:
70: Assume that loncapa is installed in /home/httpd/lib/perl so that we can use
71: it's modules. If this is not the case, you must modify the
72: use lib line in the program before you can use it.
73:
74:
75: =cut
76:
77: use strict;
78:
79: # I'm not sure if there's a better way to establish the location of the libs:
80:
81: use lib ('/home/httpd/lib/perl');
82:
83: use LONCAPA::Configuration;
84: use File::Basename;
85: use Apache::lonnet;
86:
87: #----------------------------------------------------------------------------------
88: #
89: # Command dispatch handling:
90:
91: #
92: # Dispatch hash for the subcommands.
93: # indexed by the subcommand name, each item is
94: # a reference to the sub that handles the command:
95: #
96:
97: my %Dispatch;
98:
99: #
100: # Define a subcommand:
101: #
102: # Parameters:
103: # command - subcommand name string
104: # handler - reference to the handler sub.
105: # Notes:
106: # The handler is dispatched to with the tail of the command
107: # as an array reference parameter. Suppose the command is
108: #
109: # clusteradmin update dns_hosts.tab,
110: #
111: # the array will have a single element: 'dns_hosts.tab'.
112: #
113: sub define_command {
114: my ($command, $handler) = @_;
115:
116: $Dispatch{$command} = $handler;
117: }
118:
119: #
120: # Dispatch to a command:
121: # Parameters:
122: # command - Name of the command.
123: # tail - Reference to the command tail array.
124: # Returns:
125: # 1 - Success.
126: # 0 - Failure
127: # Notes:
128: # 1. The command handler is assumed to have output any error messages
129: # to stderr by now.
130: # 2. This function will indicate to stderr if the command isn't in the
131: # dispatch hash.
132: #
133: sub dispatch_command {
134: my ($command, $tail) = @_;
135: my $sub;
136:
137: if (exists($Dispatch{$command})) {
138: $sub = $Dispatch{$command};
139: return $sub->($tail);
140: } else {
141: print STDERR "Unrecognized subcommand keyword $command\n";
142: &usage();
143: return 0;
144: }
145: }
146: #-----------------------------------------------------------------------------------
147:
148: #
149: # Provide usage/help string:
150: #
151:
152: sub usage {
153: print STDERR "Usage:\n";
154: print STDERR " clusteradmin subcommand [args]\n";
155: print STDERR "Where:\n";
156: print STDERR " subcommand describes what to actually do:\n";
157: print STDERR " help - Prints this message (args ignored)\n";
158: print STDERR " update - Updates an administrative file\n";
159: print STDERR " args is one of dns_hosts.tab or dns_domain.tab\n";
160:
161: }
162:
163: &define_command("help", \&usage);
164:
165:
166: #--------------------------------------------------------------------------------
167: #
168: # File update subsystem:
169:
170:
171: # Given the basename of an administrative file, return the
172: # full path to that file.
173: # Pre-requisistes:
174: # Requires that LONCAPA::Configuration is in the use lib path.
175: # Parameters:
176: # $basename - Base name of the file to locate.
177: # Returns:
178: # Full path to that file.
179: #
180:
181: my $config_vars = LONCAPA::Configuration::read_conf('loncapa.conf');
182: my %config = %{$config_vars};
183: my $logfile = $config{'lonDaemons'}.'/logs/dns_updates.log';
184:
185:
186: sub construct_table_path {
187: my ($basename) = @_;
188: my $directory = $config{'lonTabDir'};
189:
190: return $directory . '/' . $basename;
191: }
192:
193: # Returns the set of hosts that are specified as DNS hosts in the hosts.tab file.
194: # Those are the ones with a ^ in column one.
195: #
196: # Returns:
197: # The list of host that are DNS hosts.
198: #
199: sub get_dns_hosts()
200: {
201: my @result;
202: my $hosts_tab = &construct_table_path('hosts.tab');
203: open(HOSTS, "<$hosts_tab");
204: while (my $line = <HOSTS>) {
205: chomp($line);
206: if ($line =~ /^\^/) {
207: if ($line =~ /^\^([\w.\-]+)/) {
208: push(@result,$1);
209: }
210: }
211: }
212: return (@result);
213: }
214:
215: # Actually push the new files to the systems to update. This is done as a critical
216: # transaction so that the files eventually get pushed, even if the target hosts
217: # are down about now.
218: #
219: # Parameters:
220: # specifier - The specifier to hand in the push transaction. This
221: # identifies the target file in the remote lond process.
222: # pushfile - Full path to the file to push.
223: # hosts - Reference to an array of hosts into which the file should be pushed.
224: #
225: # Returns:
226: # 1 - Success.
227: # 0 - Failure with appropriate output to stderr.
228: #
229: sub push_file {
230: my ($specifier, $pushfile, $hosts, $fh) = @_;
231:
232: # Read in the entire file:
233:
234: my $contents;
235: my $line;
236: open(FILE, "<$pushfile");
237: while ($line = <FILE>) {
238: $contents .= $line;
239: }
240:
241:
242: # Construct the transaction for safety we encrypt the transaction
243: #
244: my $cmd = "encrypt:pushfile:$specifier:$contents";
245:
246: # Iterate over the hosts and run cmd as a critical
247: # operation:
248:
249: my @ids=&Apache::lonnet::current_machine_ids();
250: foreach my $host (@$hosts) {
251: my $loncapa_name = &Apache::lonnet::host_from_dns($host);
252: next if (grep(/^\Q$loncapa_name\E$/,@ids));
253: my $reply = &Apache::lonnet::critical($cmd, $loncapa_name);
254: my $msg;
255: if ($reply eq 'ok') {
256: $msg = "$pushfile pushed to $host ($loncapa_name): $reply\n";
257: } else {
258: $msg = "Reply from $host ($loncapa_name) not 'ok' was: $reply\n";
259: }
260: print $fh $msg;
261: print STDERR $msg;
262: }
263: return;
264: }
265:
266: #
267: # Controls the push of a file to the servers that deserve to get it.
268: # Parameters:
269: # args - Tail of the command line (array reference).
270: # Returns:
271: # 1 - Success.
272: # 0 - Failure (printing messages to stderr.
273: #
274: sub update_file {
275: my ($args) = @_;
276:
277: if (scalar(@$args) != 1) {
278: print STDERR "Incorrect number of command arguments\n";
279: &usage();
280: return 0;
281: } else {
282: my $filename = shift(@$args);
283:
284: # Validate the filename:
285:
286: if (($filename eq 'dns_hosts.tab') || ($filename eq 'dns_domain.tab') ||
287: ($filename eq 'hosts.tab') || ($filename eq 'domain.tab')) {
288: my ($result,$fh);
289: if (!-e $logfile) {
290: system("touch $logfile");
291: system("chown www:www $logfile");
292: }
293: if (open ($fh,">>$logfile")) {
294: print $fh "clusteradmin update started: ".localtime(time)."\n";
295: my $pushfile = &construct_table_path($filename);
296: my $specifier = basename($filename, ('.tab'));
297: my @hosts = (&get_dns_hosts());
298: $result = &push_file($specifier, $pushfile, \@hosts, $fh);
299: print $fh "ended: ".localtime(time)."\n";
300: close($fh);
301: } else {
302: print STDERR "Could not open $logfile to append. Exiting.\n";
303: }
304: return $result;
305: } else {
306: print STDERR "Only dns_hosts.tab or dns_domain.tab can be updated\n";
307: &usage();
308: return 0;
309: }
310: }
311: }
312: &define_command("update", \&update_file);
313:
314: #
315: # Checks if current lonHostID is in managers.tab for the cluster, and is in the cluster.
316: # Parameters:
317: # args - none
318: # Returns:
319: # 1 - lonHostID is is managers.tab
320: # '' - Failure (printing messages to STDERR).
321: #
322: sub is_manager {
323: my $currhost = $config{'lonHostID'};
324: my $canmanage;
325: if ($currhost eq '') {
326: print STDERR "Could not determine LON-CAPA host ID\n";
327: return;
328: } elsif (!defined &Apache::lonnet::get_host_ip($currhost)) {
329: print STDERR "This LON-CAPA host is not part of the cluster.\n";
330: }
331: my $tablename = &construct_table_path('managers.tab');
332: if (!open (MANAGERS, $tablename)) {
333: print STDERR "No managers.tab table. Could not verify host is a manager\n";
334: return;
335: }
336: while(my $host = <MANAGERS>) {
337: chomp($host);
338: next if ($host =~ /^\#/);
339: if ($host eq $currhost) {
340: $canmanage = 1;
341: last;
342: }
343: }
344: close(MANAGERS);
345: return $canmanage;
346: }
347: #---------------------------------------------------------------------------------
348: #
349: # Program entry point. Decode the subcommand from the args array and
350: # dispatch to the appropriate command processor.
351: #
352:
353: if ($< != 0) { # Am I root?
354: print('You must be root in order to run clusteradmin.'.
355: "\n");
356: exit(-1);
357: }
358:
359: my $argc = scalar(@ARGV);
360: if ($argc == 0) {
361: print STDERR "Missing subcommand\n";
362: &usage();
363: exit(-1);
364: }
365:
366: if (!&is_manager()) {
367: print STDERR 'Script needs to be run from a server designated as a "Manager" in the LON-CAPA cluster'."\n";
368: exit(-1);
369: }
370:
371: my $subcommand = shift(@ARGV); # argv now the tail.
372:
373: if (!&dispatch_command($subcommand, \@ARGV)) {
374: exit(0);
375: } else {
376: exit(-1);
377: }
378:
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