eventsys.proxy.in 4.29 KB
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#!/usr/bin/perl -w

#
# EMULAB-COPYRIGHT
# Copyright (c) 2000-2004 University of Utah and the Flux Group.
# All rights reserved.
#

use English;
use Getopt::Std;
use Errno;
use POSIX ":sys_wait_h";
    
#
# A wrapper for controlling the event scheduler from boss. 
#
# The first argument option is the user to run this script as, since we
# get invoked by a root ssh from boss. 
#
#
sub usage()
{
    print "Usage: eventsys.proxy -u user -g gid -e pid/eid -k keyfile ".
	"-l logfile start|stop|replay\n";
    exit(-1);
}
my $optlist = "u:e:k:dl:g:";
my $debug   = 0;
my $user;
my $pid;
my $eid;
my $gid;
my $keyfile;
my $logfile;
my $action;

#
# Configure variables
#
my $TB       = "@prefix@";
my $TBOPS    = "@TBOPSEMAIL@";
my $sched    = "$TB/sbin/event-sched";
my $PIDDIR   = "/var/run/emulab/evsched";
my $PIDFILE;

#
# Turn off line buffering on output
#
$| = 1;

#
# Untaint the path
# 
$ENV{'PATH'} = "/bin:/usr/bin:/sbin:/usr/sbin:/usr/local/bin";
delete @ENV{'IFS', 'CDPATH', 'ENV', 'BASH_ENV'};

#
# Only real root, cause the script has to read/write a pid file that
# cannot be accessed by the user.
#
if ($UID != 0) {
    die("*** $0:\n".
	"    Must be root to run this script!\n");
}

#
# Testbed Support libraries
#
use lib "@prefix@/lib";
use libtestbed;

#
# Parse command arguments. Once we return from getopts, all that should be
# left are the required arguments.
#
%options = ();
if (! getopts($optlist, \%options)) {
    usage();
}
if (@ARGV != 1) {
    usage();
}
if (! defined($options{"u"}) ||
    ! defined($options{"e"}) ||
    ! defined($options{"g"}) ||
    ! defined($options{"l"}) ||
    ! defined($options{"k"})) {
    usage();
}    
	    
if (defined($options{"d"})) {
    $debug = 1;
}

$logfile    = $options{"l"};
$keyfile    = $options{"k"};
$user       = $options{"u"};
$gid        = $options{"g"};
$action     = $ARGV[0];

if ($options{"e"} =~ /^([-\w]*)\/([-\w]*)$/) {
    $pid = $1;
    $eid = $2;
}
else {
    usage();
}
$PIDFILE = "$PIDDIR/${pid}_${eid}.pid";

#
# Deal with stop and replay.
#
if ($action eq "stop" || $action eq "replay") {
    if (-e $PIDFILE) {    
	my $epid = `cat $PIDFILE`;
	# untaint
	if ($epid =~ /^(\d*)$/) {
	    $epid = $1;
	}
	else {
	    die("*** $0:\n".
		"    Bad data in pid: $epid!\n");
	}
	unlink($PIDFILE);

	if (kill($epid, 0) == 0 || $Errno::errno != $Errno::ESRCH) {
	    if (! kill('TERM', $epid)) {
		die("*** $0:\n".
		    "Failed to stop event system for $pid/$eid!\n");
	    }
	}
    }
    
    if ($action eq "stop") {
	exit(0);
    }
    # replay continues below, but give exiting scheduler a chance to react!
    sleep(1);
}

#
# Make sure the pid directory exists.
#
if (! -d $PIDDIR) {
    if (system("mkdir -p -m 775 $PIDDIR")) {
	die("*** $0:\n".
	    "    Could not mkdir $PIDDIR\n");
    }
}

#
# Okay, now flip to user before running the event scheduler. Must put the
# user into both the project group and the experiment subgroup.
#
my (undef,undef,$unix_uid) = getpwnam($user) or
    die("*** $0:\n".
	"    No such user $user\n");

my (undef,undef,$unix_ggid) = getgrnam($gid) or
    die("*** $0:\n".
	"    No such group $gid\n");

my (undef,undef,$unix_pgid) = getgrnam($pid) or
    die("*** $0:\n".
	"    No such group $pid\n");

#
# Create a chile whose output is directed into the logfile. Parents waits
# a moment and then exits.
#
if (-e $logfile) {
    system("mv -f $logfile ${logfile}.old");
}

if (my $childpid = TBBackGround($logfile)) {
    #
    # Delay a moment, and they look for an exit status. This is intended
    # to catch startup problems.
    #
    sleep(1);
    my $foo = waitpid($childpid, &WNOHANG);
    if ($foo) {
	my $status = $?;
	unlink($PIDFILE);

	system("cat $logfile")
	    if (-s $logfile);
	
	die("*** $0:\n".
	    "    Failed to start event system for $pid/$eid: $foo $status!\n");
    }
    exit(0);
}

#
# Write out a pid file just prior to doing the exec. The user is not granted
# access to this pid file.
#
if (system("echo '$PID' > $PIDFILE")) {
    die("*** $0:\n".
	"    Could not create $PIDFILE!");
}

# Flip to user and never go back!
$GID            = $unix_ggid;
$EGID           = "$unix_ggid $unix_ggid $unix_pgid";
$EUID = $UID    = $unix_uid;
$ENV{'USER'}    = $user;
$ENV{'LOGNAME'} = $user;

# And run it.
exec("$sched " . ($debug ? "-d" : "") . " -s localhost -k $keyfile $pid $eid");
die("*** $0:\n".
    "    Could not exec $sched!");