File:  [LON-CAPA] / loncom / Attic / lonManage
Revision 1.15: download - view: text, annotated - select for diffs
Tue Sep 16 09:49:54 2003 UTC (20 years, 6 months ago) by foxr
Branches: MAIN
CVS tags: HEAD
Adjust the usage message to reflect what actually will happen on
--reinit={lond|lonc}

#!/usr/bin/perl
# The LearningOnline Network with CAPA
#
#  lonManage supports remote management of nodes in a LonCAPA cluster.
#
#  $Id: lonManage,v 1.15 2003/09/16 09:49:54 foxr Exp $
#
# $Id: lonManage,v 1.15 2003/09/16 09:49:54 foxr Exp $
#
# Copyright Michigan State University Board of Trustees
#
# This file is part of the LearningOnline Network with CAPA (LON-CAPA).
## LON-CAPA is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2 of the License, or
# (at your option) any later version.
#
# LON-CAPA is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with LON-CAPA; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#
# /home/httpd/html/adm/gpl.txt
#
# http://www.lon-capa.org/
#
#
#   lonManage supports management of remot nodes in a lonCAPA cluster.
#   it is a command line tool.  The following command line syntax (usage)
#   is supported:
#
#    lonManage  -push   <tablename>  newfile  host
#        Push <tablename> to the lonTabs directory.  Note that
#        <tablename> must be one of:
#           host  (hosts.tab)
#           domain (domain.tab)
#
#    lonManage  -reinit lonc host
#           Sends a HUP signal to the remote systems's lond.
#
#    lonmanage  -reinit lond host
#          Requests the remote system's lond perform the same action as if
#          it had received a HUP signal.
#
#    In the above syntax, the host above is the hosts.tab name of a host,
#    not the IP address of the host.
#
#  $Log: lonManage,v $
#  Revision 1.15  2003/09/16 09:49:54  foxr
#  Adjust the usage message to reflect what actually will happen on
#  --reinit={lond|lonc}
#
#  Revision 1.14  2003/09/08 09:45:20  foxr
#  Remove BUGBUG about comment about authentication as we'll be doing
#  host based authentication initially (no need for lonManage to do anything),
#  and certificate based later (need at that time).
#
#  Revision 1.13  2003/08/19 10:26:24  foxr
#  Initial working version... tested against an unmodified lond this
#  produces an unknown_cmd response which is about what I'd expect.
#
#  Revision 1.12  2003/08/18 11:08:07  foxr
#  Debug request building in Transact.
#
#  Revision 1.11  2003/08/18 10:45:32  foxr
#  Felt strongly enough about hoisting ReadConfiguration into a separate sub
#  that I did it now before I forgot.
#
#  Revision 1.10  2003/08/18 10:43:31  foxr
#  Code/test ValidHost.  The hosts.tab and the perl variables are read in as
#  global hashes as a side effect.  May later want to clean this up by making
#  a separate getconfig function and hoisting the config reads into that.
#
#  Revision 1.9  2003/08/18 10:25:46  foxr
#  Write ReinitProcess function in terms of ValidHost and Transact.
#
#  Revision 1.8  2003/08/18 10:18:21  foxr
#  Completed PushFile function in terms of
#  - ValidHost - Determines if target host is valid.
#  - Transact  - Performs one of the valid transactions with the
#                appropriate lonc<-->lond client/server pairs.
#
#  Revision 1.7  2003/08/18 09:56:01  foxr
#  1. Require to be run as root.
#  2. Catch case where no operation switch is supplied and put out usage.
#  3. skeleton/comments for PushFile function.
#
#  Revision 1.6  2003/08/12 11:02:59  foxr
#  Implement command switch dispatching.
#
#  Revision 1.5  2003/08/12 10:55:42  foxr
#  Complete command line parsing (tested)
#
#  Revision 1.4  2003/08/12 10:40:44  foxr
#  Get switch parsing right.
#
#  Revision 1.3  2003/08/12 10:22:35  foxr
#  Put in parameter parsing infrastructure
#
#  Revision 1.2  2003/08/12 09:58:49  foxr
#  Add usage and skeleton documentation.
#
#



# Modules required:

use strict;			# Because it's good practice.
use English;			# Cause I like meaningful names.
use Getopt::Long;
use LONCAPA::Configuration;	# To handle configuration I/O.
use IO::Socket::UNIX;		# To communicate with lonc.

# File scoped variables:

my %perlvar;			# Perl variable defs from apache config.
my %hostshash;			# Host table as a host indexed hash.

#
#   prints out utility's command usage info.
#
sub Usage  {
    print "Usage:";
    print <<USAGE;
    lonManage  --push=<tablename>  newfile  host
        Push <tablename> to the lonTabs directory.  Note that
        <tablename> must be one of:
           host  (hosts.tab)
           domain (domain.tab)

    lonManage  --reinit=lonc host
       Causes lonc in the remote system to reread hosts.tab and
       adjust the set of clients that are being maintained to match
       the new file.
       

    lonManage  --reinit=lond host
       Causes lond in the remote system to reread the hosts.tab file
       and adjust the set of servers to match changes in that file.

    In the above syntax, the host above is the hosts.tab name of a host,
    not the IP address of the host.
USAGE


}
#
#   Lifted from lonnet.pm - and we need to figure out a way to get it back in.
#   Performas a transaction with lond via the lonc proxy server.
#   Parameter:
#      cmd  - The text of the request.
#      host - The host to which the request ultimately goes.
#   Returns:
#      The text of the reply from the lond or con_lost if not able to contact
#      lond/lonc etc.
#
sub subreply {
    my ($cmd,$server)=@_;
    my $peerfile="$perlvar{'lonSockDir'}/$server";
    my $client=IO::Socket::UNIX->new(Peer    =>"$peerfile",
                                     Type    => SOCK_STREAM,
                                     Timeout => 10)
       or return "con_lost";
    print $client "$cmd\n";
    my $answer=<$client>;
    if (!$answer) { $answer="con_lost"; }
    chomp($answer);
    return $answer;
}
#   >>> BUGBUG <<< 
#
#  Use Getopt::Long to parse the parameters of the program.
#
#  Return value is a list consisting of:
#    A 'command' which is one of:
#       push   - table push requested.
#       reinit - reinit requested.
#   Additional parameters as follows:
#       for push: Tablename, hostname
#       for reinit: Appname  hostname
#
#   This function does not validation of the parameters of push and
#   reinit.
#
#   returns a list.  The first element of the list is the operation name
#   (e.g. reinit or push).  The second element is the switch parameter.
#   for push, this is the table name, for reinit, this is the process name.
#   Additional elements of the list are the command argument.  The count of
#   command arguments is validated, but not their semantics.
#
#   returns an empty list if the parse fails.
#

sub ParseArgs {
    my $pushing   = '';
    my $reinitting = '';

    if(!GetOptions('push=s'    => \$pushing,
	           'reinit=s'  => \$reinitting)) {
	return ();
    }

    #  Require exactly   one of --push and --reinit

    my $command    = '';
    my $commandarg = '';
    my $paramcount = @ARGV; 	# Number of additional arguments.
    

    if($pushing ne '') {

        # --push takes in addition a table, and a host:
        #
	if($paramcount != 2) {
	    return ();		# Invalid parameter count.
	}
	if($command ne '') {
	    return ();
	} else {
	    
	    $command    = 'push';
	    $commandarg = $pushing;
	}
    }

    if ($reinitting ne '') {

	# --reinit takes in addition just a host name

	if($paramcount != 1) {
	    return ();
	}
	if($command ne '') {
	    return ();
	} else {
	    $command    = 'reinit';
	    $commandarg = $reinitting; 
	}
    }

    #  Build the result list:

    my @result = ($command, $commandarg);
    my $i;
    for($i = 0; $i < $paramcount; $i++) {
	push(@result, $ARGV[$i]);
    }
    
    return @result;
}
#
#  Read the loncapa configuration stuff.
#
sub ReadConfig {
    my $perlvarref = LONCAPA::Configuration::read_conf('loncapa.conf');
    %perlvar       = %{$perlvarref};
    my $hoststab   = LONCAPA::Configuration::read_hosts(
					"$perlvar{'lonTabDir'}/hosts.tab");
    %hostshash     = %{$hoststab};

}
#
#  Determine if the target host is valid.
#  This is done by reading the current hosts.tab file.
#  For the host to be valid, it must be inthe file.
#
#  Parameters:
#     host   - Name of host to check on.
#  Returns:
#     true   if host is valid.
#     false  if host is invalid.
#
sub ValidHost {
    my $host       = shift;
   
    ReadConfig;

    return defined $hostshash{$host};

}



#
#  Performs a transaction with lonc.
#  By the time this is called, the transaction has already been
#  validated by the caller.
#
#   Parameters:
#
#   host    - hosts.tab name of the host whose lonc we'll be talking to.
#   command - The base command we'll be asking lond to execute.
#   body    - [optional] If supplied, this is a command body that is a ref.
#             to an array of lines that will be appended to the 
#             command.
#
#  NOTE:
#    The command will be done as an encrypted operation.
#
sub Transact {
    my $host    = shift;
    my $command = shift;
    my $haveBody= 0;
    my $body;
    my $i;

    if(scalar @ARG) {
	$body = shift;
	$haveBody = 1;
    }
    #  Construct the command to send to the server:
    
    my $request = "encrypt\:";	# All requests are encrypted.
    $request   .= $command;
    if($haveBody) {
	$request .= "\:";
	my $bodylines = scalar @$body;
	for($i = 0; $i < $bodylines; $i++) {
	    $request .= $$body[$i];
	}
    } else {
	$request .= "\n";
    }
    # Body is now built... transact with lond..
    
    my $answer = subreply($request, $host);

    print "$answer\n";

}
#
#   Called to push a file to the remote system.
#   The only legal files to push are hosts.tab and domain.tab.
#   Security is somewhat improved by
#   
#   - Requiring the user run as root.
#   - Connecting with lonc rather than lond directly ensuring this is a loncapa
#     host
#   - We must appear in the remote host's hosts.tab file.
#   - The host must appear in our hosts.tab file.
#
#  Parameters:
#     tablename - must be one of hosts or domain.
#     tablefile - name of the file containing the table to push.
#     host      - name of the host to push this file to.     
#
#    >>>BUGBUG<<< This belongs in lonnet.pm.
#
sub PushFile {
    my $tablename = shift;
    my $tablefile = shift;
    my $host      = shift;
    
    # Open the table file:

    if(!open(TABLEFILE, "<$tablefile")) {
	die "ENOENT - No such file or directory $tablefile";
    }
  
    # Require that the host be valid:

    if(!ValidHost($host)) {
	die "EHOSTINVAL - Invalid host $host"; # Ok so I invented this 'errno'.
    }
    # Read in the file.  If the table name is valid, push it.

    my @table = <TABLEFILE>;	#  These files are pretty small.
    close TABLEFILE;

    if( ($tablename eq "host")    ||
	($tablename eq "domain")) {
	Transact($host, "pushfile:$tablename",\@table);
    } else {
	die "EINVAL - Invalid parameter. tablename: $tablename must be host or domain";
    }
}
#
#   This function is called to reinitialize a server in a remote host.
#   The servers that can be reinitialized are:
#   - lonc   - The lonc client process.
#   - lond   - The lond daemon.
#  NOTE:
#    Reinitialization in this case means re-scanning the hosts table,
#    starting new lond/lonc's as approprate and stopping existing lonc/lond's.
#
#  Parameters:
#     process - The name of the process to reinit (lonc or lond).
#     host    - The host in which this reinit will happen.
#
#   >>>BUGBUG<<<< This belongs  in lonnet.pm
#
sub ReinitProcess {
    my $process = shift;
    my $host    = shift;

    #  Ensure the host is valid:
    
    if(!ValidHost($host)) {
	die "EHOSTINVAL - Invalid host $host";
    }
    # Ensure target process selector is valid:

    if(($process eq "lonc") ||
       ($process eq "lond")) {
	Transact($host, "reinit:$process");
    } else {
	die "EINVAL -Invalid parameter. Process $process must be lonc or lond";
    }
}
#--------------------------- Entry point: --------------------------

#  Parse the parameters
#  If command parsing failed, then print usage:

my @params   = ParseArgs;
my $nparam   = @params;

if($nparam == 0) {
    Usage;
    exit -1;
}
#
#   Next, ensure we are running as EID root.
#
if ($EUID != 0) {
    die "ENOPRIV - No privilege for requested operation"
}


#   Based on the operation requested invoke the appropriate function:

my $operation = shift @params;

if($operation eq "push") {  # push tablename filename host
    my $tablename = shift @params;
    my $tablefile = shift @params;
    my $host      = shift @params;
    PushFile($tablename, $tablefile, $host);

} elsif($operation eq "reinit") {	# reinit processname host.
    my $process   = shift @params;
    my $host      = shift @params;
    ReinitProcess($process, $host);
}
else {
    Usage;
}
exit 0;

=head1 NAME
    lonManage - Command line utility for remote management of lonCAPA
    cluster nodes.

=head1 SYNOPSIS

Usage:
    B<lonManage  --push=<tablename>  newfile  host>
        Push <tablename> to the lonTabs directory.  Note that
        <tablename> must be one of:
           hosts  (hosts.tab)
           domain (domain.tab)

    B<lonManage  --reinit=lonc host>
           Sends a HUP signal to the remote systems's lond.

    B<lonmanage  --reinit=lond host>
          Requests the remote system's lond perform the same action as if
          it had received a HUP signal.

    In the above syntax, the host above is the hosts.tab name of a host,
    not the IP address of the host.


=head1 DESCRIPTION

=head1 PREREQUISITES

=item strict
=item Getopt::Long
=item English
=item IO::Socket::UNIX

=head1 KEY Subroutines.

=head1  CATEGORIES
    Command line utility

=cut

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