swapexp.in

#!/usr/bin/perl -wT

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

use English;
use Getopt::Std;
use POSIX qw(isatty setsid);

#
# This gets invoked from the Web interface.
# Swap an experiment in, swap it out, restart or modify.
#

sub usage()
{
    print(STDERR
	  "Usage: swapexp [-q] [-b | -w] [-i | -a | -f] [-r] [-e]\n".
	  "               <-s in | out | restart | modify | pause>\n".
	  "               <pid> <eid> [<nsfile>]\n".
	  "switches and arguments:\n".
	  "-w       - wait for non-batchmode experiment swap/modify\n".
	  "-q       - be less chatty\n".
	  "-r       - reboot nodes when doing a modify experiment\n".
	  "-e       - restart event scheduler when doing a modify experiment\n".
	  "-s <op>  - Operation to perform; one of those listed above\n".
	  "<pid>    - The project the experiment belongs to\n".
	  "<eid>    - The experiment name (id)\n".
	  "<nsfile> - Optional NS file to parse for experiment modify\n");
    exit(-1);
}
my  $optlist = "biafres:wq";

#
# Exit codes are important; they tell the web page what has happened so
# it can say something useful to the user. Fatal errors are mostly done
# with die(), but expected errors use this routine. At some point we will
# use the DB to communicate the actual error.
#
# $status < 0 - Fatal error. Something went wrong we did not expect.
# $status = 0 - Termination is proceeding in the background. Notified later.
# $status > 0 - Expected error. User not allowed for some reason. 
# 
sub ExitWithStatus($$)
{
    my ($status, $message) = @_;
    
    if ($status < 0) {
	die("*** $0:\n".
	    "    $message\n");
    }
    else {
	print STDERR "$message\n";
    }
    exit($status);
}

#
# Configure variables
#
my $TB     = "@prefix@";
my $TBOPS  = "@TBOPSEMAIL@";
my $TBLOGS = "@TBLOGSEMAIL@";
my $TBINFO = "$TB/expinfo";
my $TBDOCBASE = "@TBDOCBASE@";
my $TBBASE = "@TBBASE@";

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

my $tbdir    = "$TB/bin/";
my $tbdata   = "tbdata";
my $batch    = 0;
my $idleswap = 0;
my $autoswap = 0;
my $force    = 0;
my $reboot   = 0;
my $waitmode = 0;
my $quiet    = 0;
my $eventsys_restart   = 0;
my $errorstat= -1;
my $modifyHosed = 0;

my $inout;
my $logname;
my $dbuid;
my $user_name;
my $user_email;
my @allnodes;
my @row;
my $action;
my $nextswapstate;
my $termswapstate;

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

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

#
# Set umask for start/swap. We want other members in the project to be
# able to swap/end experiments, so the log and intermediate files need
# to be 664 since some are opened for append.
#
umask(0002);

#
# Parse command arguments. Once we return from getopts, all that should
# left are the required arguments.
#
%options = ();
if (! getopts($optlist, \%options)) {
    usage();
}
if (defined($options{"i"})) {
    $idleswap = 1;
}
if (defined($options{"w"})) {
    $waitmode = 1;
}
if (defined($options{"a"})) {
    $autoswap = 1;
}
if (defined($options{"f"})) {
    $force = 1;
}
if (defined($options{"b"})) {
    $batch = 1;
}
if (defined($options{"r"})) {
    $reboot = 1;
}
if (defined($options{"e"})) {
    $eventsys_restart = 1;
}
if (defined($options{"q"})) {
    $quiet = 1;
}
if (defined($options{"s"})) {
    $inout = $options{"s"};

    if ($inout ne "out"     &&
	$inout ne "in"      &&
	$inout ne "restart" &&
	$inout ne "pause"   &&
	$inout ne "modify") {
	usage();
    }
}
else {
    usage();
}

usage()
    if (($waitmode && $batch) ||
	($inout ne "modify" && @ARGV != 2) ||
	(($waitmode || $batch) && ($idleswap || $autoswap || $force)));

if ($eventsys_restart && $inout ne "modify") {
    print STDOUT "Usage: swapexp: -e (eventsys_restart) can be used ".
                 "only with -s modify\n";
    usage();
}
my $pid   = $ARGV[0];
my $eid   = $ARGV[1];

#
# Untaint the arguments.
#
if ($pid =~ /^([-\w\.]+)$/) {
    $pid = $1;
}
else {
    die("Tainted argument $pid!\n");
}
if ($eid =~ /^([-\w\.]+)$/) {
    $eid = $1;
}
else {
    die("Tainted argument $eid!\n");
}
my $repfile = "$eid.report";
my $workdir = TBExptWorkDir($pid, $eid);
my $userdir = TBExptUserDir($pid, $eid);
my $tempnsfile;
my $modnsfile;

if ($inout eq "modify" && @ARGV > 2) {
    $tempnsfile = $ARGV[2];

    #
    # Untaint nsfile argument; Allow slash.
    #
    if ($tempnsfile =~ /^([-\w\.\/]+)$/) {
	$tempnsfile = $1;
    }
    else {
	die("Tainted nsfile name: $tempnsfile\n");
    }
    #
    # Called from ops interactively. Make sure NS file in /proj or /users.
    #
    # Use realpath to resolve any symlinks.
    #
    my $translated = `realpath $tempnsfile`;
    if ($translated =~ /^([-\w\.\/]+)$/) {
	$tempnsfile = $1;
    }
    else {
	die("Tainted nsfile returned by realpath: $translated\n");
    }

    #
    # The file must reside in /proj, /groups, or /users. Since this script
    # runs as the caller, regular file permission checks ensure its a file
    # the user is allowed to use. /tmp/$guid-$nsref.nsfile also allowed
    # since this script is invoked directly from web interface, which generates
    # a name that should not be guessable, so as long as it looks to be in
    # proper format, we accept it. 
    #
    if (! ($tempnsfile =~ /^\/tmp\/[-\w]+-\d+\.nsfile/) &&
	! ($tempnsfile =~ /^\/var\/tmp\/php\w+/) &&
	! ($tempnsfile =~ /^\/proj/) &&
	! ($tempnsfile =~ /^\/groups/) &&
	! ($tempnsfile =~ /^\/users/)) {
	die("$tempnsfile does not resolve to an appropriate directory!\n");
    }

    if (! -f $tempnsfile || -z $tempnsfile || ! -r $tempnsfile) {
	die("*** $0:\n".
	    "    $tempnsfile does not look like an NS file!\n");
    }
    $modnsfile = "$eid-modify.ns";
}

#
# Verify user and get his DB uid.
#
if (! UNIX2DBUID($UID, \$dbuid)) {
    die("*** $0:\n".
	"    You do not exist in the Emulab Database.\n");
}

#
# Get email info for user.
#
if (! UserDBInfo($dbuid, \$user_name, \$user_email)) {
    die("*** $0:\n".
	"    Cannot determine your name and email address.\n");
}

#
# Verify that this person can muck with the experiment.
# Note that any script down the line has to do an admin check also. 
#
if ($UID && !TBAdmin($UID) &&
    !TBExptAccessCheck($dbuid, $pid, $eid, TB_EXPT_DESTROY)) {
    die("*** $0:\n".
	"    You do not have permission to swap or modify this experiment!\n");
}

# Must do this before lock tables!
# idleswap is in minutes, threshold is in hours
$idleswap_time = 60 * TBGetSiteVar("idle/threshold");

#
# In wait mode, block interrupt until we spin off the background process.
#
if ($waitmode) {
    $SIG{TERM} = 'IGNORE';
    $SIG{QUIT} = 'IGNORE';
    $SIG{INT}  = 'IGNORE';
}

#
# We have to protect against trying to end an experiment that is currently
# in the process of being terminated. We use a "wrapper" state (actually
# a timestamp so we can say when termination was requested) since
# terminating consists of a couple of different experiment states down inside
# the tb scripts.
#
DBQueryFatal("lock tables experiments write");

$query_result =
    DBQueryFatal("SELECT * FROM experiments WHERE eid='$eid' and pid='$pid'");

if (! $query_result->numrows) {
    die("*** $0:\n".
	"    No such experiment $pid/$eid exists!\n");
}
my %hashrow = $query_result->fetchhash();
my $expt_head_login = $hashrow{'expt_head_uid'};
my $estate          = $hashrow{'state'};
my $batchstate      = $hashrow{'batchstate'};
my $expt_path       = $hashrow{'path'};
my $expt_locked     = $hashrow{'expt_locked'};
my $isbatchexpt     = $hashrow{'batchmode'};
my $canceled        = $hashrow{'canceled'};
my $linktest_level  = $hashrow{'linktest_level'};
my $swappablebit= $hashrow{'swappable'};
my $idleswapbit = $hashrow{'idleswap'};
my $autoswapbit = $hashrow{'autoswap'};
my $swappablestr= ( $swappablebit ? "Yes" : "No" );
my $idleswapstr = ( $idleswapbit ? "Yes" : "No" );
my $autoswapstr = ( $autoswapbit ? "Yes" : "No" );
my $noswap      = $hashrow{'noswap_reason'};
my $noidleswap  = $hashrow{'noidleswap_reason'};
my $idleswaptime= $hashrow{'idleswap_timeout'} / 60.0;
my $autoswaptime= $hashrow{'autoswap_timeout'} / 60.0;

if ($inout ne "out") {
    # I'm going to update this below, so fix the value before I use it.
    $idleswap_time = min($idleswaptime * 60, $idleswap_time);
    $idleswaptime = $idleswap_time / 60.0;
}

my $swapsettings = 
  "Idle-Swap:   $idleswapstr".
  ($idleswapbit ? ", at $idleswaptime hours\n" : " (Reason: $noidleswap)\n").
  "Auto-Swap:   $autoswapstr".
  ($autoswapbit ? ", at $autoswaptime hours\n" : "\n");

if (! chdir($workdir)) {
    die("*** $0:\n".
	"    Could not chdir to $workdir: $!\n");
}

#
# This script is called from the batch daemon.
# 
if ($batch) {
    #
    # Sanity Check. If called from the daemon, must already be locked,
    # must be a batch experiment, and must be in proper state for the
    # operation requested. 
    #
    die("*** $0:\n".
	"    Experiment $pid/$eid is supposed to be a batch experiment!\n")
	if (!$isbatchexpt);
    
    die("*** $0:\n".
	"    Batch experiment $pid/$eid should be locked!\n")
	if (!defined($expt_locked) ||
	    $batchstate ne BATCHSTATE_LOCKED());

    if ($inout eq "in") {
	die("*** $0:\n".
	    "    Batch experiment $pid/$eid is not in the proper state!\n".
	    "    Currently $estate, but should be QUEUED.\n")
	    if ($estate ne EXPTSTATE_QUEUED);
	
	die("*** $0:\n".
	    "    Batch experiment $pid/$eid has been canceled! Aborting.\n")
	    if ($canceled);
    }
    elsif ($inout eq "out") {
	die("*** $0:\n".
	    "    Batch experiment $pid/$eid is not in the proper state!\n".
	    "    Currently $estate, but should be ACTIVE.\n")
	    if ($estate ne EXPTSTATE_ACTIVE);
    }
    else {
	die("*** $0:\n".
	    "    Improper request from batch daemon for $pid/$eid!\n");
    }
}
else {
    if ($isbatchexpt) {
	#
	# User is requesting that a batch either be injected or paused.
	# Sanity check the state, but otherwise let the batch daemon
	# handle it.
	#
	ExitWithStatus(1, "Batch experiment $pid/$eid is still canceling!")
	    if ($canceled);

	if ($inout eq "in") {
	    ExitWithStatus(1,
			   "Batch experiment $pid/$eid must be SWAPPED to\n".
			   "QUEUE. Currently $estate.")
		if ($estate ne EXPTSTATE_SWAPPED);
	    SetExpState($pid, $eid, EXPTSTATE_QUEUED);
	}
	elsif ($inout eq "out") {
	    ExitWithStatus(1,
			   "Batch experiment $pid/$eid must be ACTIVE or\n".
			   "ACTIVATING to swap out. Currently $estate.")
		if ($estate ne EXPTSTATE_ACTIVE &&
		    $estate ne EXPTSTATE_ACTIVATING);

	    #
	    # Since the batch daemon has control, all we can do is set
	    # the cancel bit.
	    # 
	    TBSetCancelFlag($pid, $eid, EXPTCANCEL_SWAP);
	}
	elsif ($inout eq "pause") {
	    ExitWithStatus(1,
			   "Batch experiment $pid/$eid must be QUEUED to\n".
			   "DEQUEUE. Currently $estate.")
		if ($estate ne EXPTSTATE_QUEUED);

	    #
	    # XXX. The batch daemon might already have the experiment, but
	    # not have shipped it off to startexp. Change the state
	    # anyway. The error will be noticed later when startexp dies,
	    # and the batch daemon gets the error back. This sucks.
	    #
	    SetExpState($pid, $eid, EXPTSTATE_SWAPPED);
	}
	elsif ($inout eq "modify") {
	    ExitWithStatus(1,
			   "Batch experiment $pid/$eid must be SWAPPED or\n".
			   "ACTIVE to modify. Currently $estate.")
		if (($estate ne EXPTSTATE_SWAPPED &&
		     $estate ne EXPTSTATE_ACTIVATING) ||
		    $batchstate != BATCHSTATE_UNLOCKED());

	    #
	    # Otherwise, proceed with the modify. The experiment will be
	    # locked below, and so it cannot be injected or otherwise messed
	    # with since its state is going to be changed before we unlock
	    # the experiments table. The batch daemon will leave it alone
	    # until the modify is done. If the modify fails and cannot recover
	    # it is going to get swapped out; that is okay since the batch
	    # daemon does not keep state internally. 
	    #
	    goto doit;
	}
	else {
	    die("*** $0:\n",
		"    Operation $inout not allowed on a batch experiment!\n");
	}
	ExitWithStatus(0, 
		       "Batch experiment $pid/$eid state has been changed.\n");
      doit:
    }
    else {
	#
	# If the cancel flag is set, then user must wait for that to
	# clear before we can do anything else.
	#
	ExitWithStatus(1,
		       "Experiment $pid/$eid has its cancel flag set!.\n".
		       "You must wait for that to clear before you can swap\n".
		       "or modify the experiment.\n")
	    if ($canceled);

	#
	# Check the state for the various operations.
	#
	if (!$force) {
	  SWITCH: for ($inout) {
	      /^in$/i && do {
		  if ($estate ne EXPTSTATE_SWAPPED()) {
		      ExitWithStatus(1,
				     "Experiment $pid/$eid is not swapped out!");
		  }
		  last SWITCH;
	      };
	      /^out$/i && do {
		  if ($estate ne EXPTSTATE_ACTIVE() &&
		      $estate ne EXPTSTATE_ACTIVATING()) {
		      ExitWithStatus(1,
				     "Experiment $pid/$eid is not swapped in ".
				     "or activating!\n");
		  }
		  
		  if ($estate eq EXPTSTATE_ACTIVATING()) {
		      #
		      # All we can do is set the cancel flag and hope that
		      # it gets noticed. We do not wait. 
		      # 
		      TBSetCancelFlag($pid, $eid, EXPTCANCEL_SWAP);
		      
		      ExitWithStatus(0,
				     "Experiment $pid/$eid swapin has been  ".
				     "marked for cancelation.\n".
				     "You will receive email when the original ".
				     "swap request has finished.");
		  }
		  last SWITCH;
	      };
	      /^restart$/i && do {
		  if ($estate ne EXPTSTATE_ACTIVE()) {
		      ExitWithStatus(1,
				     "Experiment $pid/$eid is not swapped in!");
		  }
		  last SWITCH;
	      };
	      /^modify$/i && do {
		  if ($estate ne EXPTSTATE_ACTIVE() &&
		      $estate ne EXPTSTATE_SWAPPED()) {
		      ExitWithStatus(1,
				     "Experiment $pid/$eid must be ACTIVE or\n".
				     "SWAPPED to modify!\n");
		  }
		  last SWITCH;
	      };
	      die("*** $0:\n".
		  "    Missing state check for action: $action\n");
	  }
	}
    }
}

#
# Determine the temporary and next state for experiment. If the experiment
# is a batch experiment, then the next state is actually handled by the
# batch daemon, but we still have to deal with the temporary state. 
#
SWITCH: for ($inout) {
    /^in$/i && do {
	$nextswapstate = EXPTSTATE_ACTIVATING();
	last SWITCH;
    };
    /^out$/i && do {
	$nextswapstate = EXPTSTATE_SWAPPING();
	last SWITCH;
    };
    /^restart$/i && do {
	$nextswapstate = EXPTSTATE_RESTARTING();
	last SWITCH;
    };
    /^modify$/i && do {
	$nextswapstate = (($estate eq EXPTSTATE_SWAPPED()) ?
			  EXPTSTATE_MODIFY_PARSE() : EXPTSTATE_MODIFY_REPARSE());
	last SWITCH;
    };
    die("*** $0:\n".
	"    Missing state check for action: $action\n");
}
 
# Update idleswap_timeout to whatever the current value is.
if ($inout ne "out") {
    DBQueryFatal("update experiments set idleswap_timeout='$idleswap_time' ".
		 "where eid='$eid' and pid='$pid'");
}

#
# On a failure, we go back to this swapstate. Might be modified below.
# 
$termswapstate = $estate;

# Lock the record, set the nextstate, and unlock the table.
TBLockExp($pid, $eid, $nextswapstate);
DBQueryFatal("unlock tables");

#
# XXX - At this point a failure is going to leave things in an
# inconsistent state. Be sure to call fatal() only since we are
# going into the background, and we have to send email since no
# one is going to see printed error messages (output goes into the
# log file, which will be sent along in the email). 
#

if ($inout eq "in") {
    $action = "swapped in";
}
if ($inout eq "out") {
    $action = "swapped out";
}
if ($inout eq "restart") {
    $action = "restarted";
}
if ($inout eq "modify") {
    $action = "modified";
}

#
# Get email address of the experiment head, which may be different than
# the person who is actually terminating the experiment, since its polite
# to let the original creator know whats going on. 
#
my $expt_head_name;
my $expt_head_email;

if (! UserDBInfo($expt_head_login, \$expt_head_name, \$expt_head_email)) {
    print STDERR "*** WARNING: ".
	         "Could not determine name/email for $expt_head_login.\n";
    $expt_head_name  = "TBOPS";
    $expt_head_email = $TBOPS;
}

#
# Before going to background, we have to copy out the NS file!
#
if ($inout eq "modify" && defined($modnsfile)) {
    unlink($modnsfile);
    if (system("/bin/cp", "$tempnsfile", "$modnsfile")) {
	die("*** $0:\n".
	    "    Could not copy $tempnsfile to $modnsfile");
    }
    chmod(0664, "$modnsfile");
}

#
# If not in batch mode, go into the background. Parent exits.
#
if (! $batch) {
    $logname = TBExptCreateLogFile($pid, $eid, "swapexp");
    TBExptSetLogFile($pid, $eid, $logname);
    TBExptOpenLogFile($pid, $eid);

    if (my $childpid = TBBackGround($logname)) {
	#
	# Parent exits normally, except if in waitmode. 
	#
	if (!$waitmode) {
	    print("Experiment $pid/$eid is now being $action.\n".
		  "You will be notified via email when the this is done.\n")
		if (! $quiet);
	    exit(0);
	}
	print("Waiting for experiment $eid to finish its swap${action}\n")
	    if (! $quiet);
	    
	if (isatty(STDIN) && !$quiet) {
	    print("You may type ^C at anytime; you will be notified via email.".
		  "\n".
		  "You will not actually interrupt the experiment itself.\n");
	}
	
	# Give child a chance to run.
	select(undef, undef, undef, 0.25);
	
	#
	# Reset signal handlers. User can now kill this process, without
	# stopping the child.
	#
	$SIG{TERM} = 'DEFAULT';
	$SIG{INT}  = 'DEFAULT';
	$SIG{QUIT} = 'DEFAULT';

	#
	# Wait until child exits or until user gets bored and types ^C.
	#
	waitpid($childpid, 0);
	
	print("Done. Exited with status: $?\n")
	    if (! $quiet);
	exit($? >> 8);
    }
}

#
# When in waitmode, must put ourselves in another process group so that
# an interrupt to the parent will not have any effect on the backend.
#
if ($waitmode) {
    POSIX::setsid();
}

#
# Gather stats; start clock ticking
#
if ($inout eq "in") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPIN, 0,
		    TBDB_STATS_FLAGS_START);
}
elsif ($inout eq "out") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPOUT, 0,
		    TBDB_STATS_FLAGS_START);
}
elsif ($inout eq "modify") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPMODIFY, 0,
		    TBDB_STATS_FLAGS_START);
}

#
# Remove old report file since its contents are going to be invalid.
#
if ($inout ne "restart" && -e $repfile) {
    unlink("$repfile");
}

#
# Sanity check states in case someone changes something.
#
if ($inout eq "out") {
    my $optarg = (($force || $idleswap) ? "-force" : "");
    
    print STDOUT "Running 'tbswap out $optarg $pid $eid'\n";
    if (system("$tbdir/tbswap out $optarg $pid $eid") != 0) {
	$errorstat = $? >> 8;
	fatal("tbswap out failed!");
    }
    SetExpState($pid, $eid, EXPTSTATE_SWAPPED);
}
elsif ($inout eq "in") {
    print STDOUT "Running 'tbswap in $pid $eid'\n";
    if (system("$tbdir/tbswap in $pid $eid") != 0) {
	$errorstat = $? >> 8;
	fatal("tbswap in failed!");
    }
    SetExpState($pid, $eid, EXPTSTATE_ACTIVE);

    system("$tbdir/tbreport -b $pid $eid 2>&1 > $repfile");
}
elsif ($inout eq "modify") {
    my $modifyError = "";
    my $oldstate    = $estate;

    GatherSwapStats($pid, $eid, $dbuid,
		    TBDB_STATS_SWAPMODIFY, 0, TBDB_STATS_FLAGS_PREMODIFY);

    print "Backing up old experiment state ... " . TBTimeStamp() . "\n";
    if (TBExptBackupVirtualState($pid, $eid)) {
	fatal("Could not backup experiment state; cannot safely continue!");
    }

    #
    # Rerun tbprerun if modifying, but only if new NS file provided.
    # Yep, we allow reswap without changing the NS file. For Shashi and SIM. 
    #
    if (defined($modnsfile)) {
	print STDOUT "Running 'tbprerun $pid $eid $modnsfile'\n";
	if (system("$tbdir/tbprerun $pid $eid $modnsfile") != 0) {
	    $modifyError = "tbprerun failed!";
	}
    }

    #
    # Our next state depends on whether the experiment was active or swapped.
    #
    if (! $modifyError) {
	if ($estate eq EXPTSTATE_SWAPPED) {
	    SetExpState($pid, $eid, EXPTSTATE_SWAPPED);
	}
	else {
	    SetExpState($pid, $eid, EXPTSTATE_MODIFY_RESWAP);
	    
	    my $optarg = ($reboot ? "-reboot" : "");
	    $optarg .= ($eventsys_restart ? " -eventsys_restart" : "");

	    print STDOUT "Running 'tbswap update $optarg $pid $eid'\n";
	    if (system("$tbdir/tbswap update $optarg $pid $eid") != 0) {
		$errorstat = $? >> 8;
		$modifyError = "tbswap update failed!";
	    }

	    #
	    # See what tbswap did. It might have swapped it out if there
	    # was an error. 
	    # 
	    if (! $modifyError) {
		SetExpState($pid, $eid, EXPTSTATE_ACTIVE);
		$estate = EXPTSTATE_ACTIVE;
	    }
	    elsif ($errorstat & 0x40) {
		#
		# Icky. Magic return code that says tbswap swapped it out.
		# We do not want tbswap to muck with states anymore, so
		# need to know what it did. At some point we should clean
		# up the exit reporting! Anyway, fatal() needs to know the
		# the right state to go back to (no longer ACTIVE).
		#
		$estate = EXPTSTATE_SWAPPED;
		$termswapstate = EXPTSTATE_SWAPPED;
                # Old accounting info.
		TBSetExpSwapTime($pid, $eid);
	    }
	}
    }

    if ($modifyError) {
	print STDOUT "Modify Error: $modifyError\n";
	print STDOUT "Recovering experiment state...\n";
	
	# Must deal with the prerender explicitly since it runs background.
	system("prerender -r $pid $eid");
	TBExptRemoveVirtualState($pid, $eid);
	
	if (TBExptRestoreVirtualState($pid, $eid) == 0) {
	    # Must deal with the prerender explicitly since it runs background.
	    system("prerender -t $pid $eid");
	    fatal("Update aborted; old state restored.");
	}
	else {
	    $modifyHosed = 1;
	    fatal("Experiment state could not be restored!");
	}
    }
    
    TBExptClearBackupState($pid, $eid);
    system("$tbdir/tbreport -b $pid $eid 2>&1 > $repfile");
}
else { # $inout eq "restart" assumed.
    print STDOUT "Running 'tbrestart $pid $eid'\n";
    if (system("$tbdir/tbrestart $pid $eid") != 0) {
	fatal("tbrestart failed!");
    }
    SetExpState($pid, $eid, EXPTSTATE_ACTIVE);
}

#
# Try to copy off the files for testbed information gathering.
#
TBSaveExpLogFiles($pid, $eid);

#
# Make a copy of the work dir in the user visible space so the user
# can see the log files. This overwrites existing files of course,
# but thats okay.
#
system("cp -Rfp $workdir/ $userdir/tbdata/");

#
# Deal with linktest. If requested, swapping in or modifying, and experiment
# is indeed active, then run it!
#
# XXX - linktest uses files from $userdir/tbdata/, so the above cp must
#       happen first!
#
if ($linktest_level && ExpState($pid, $eid) eq EXPTSTATE_ACTIVE) {
    #
    # Run it. No worries about failures.
    #
    my $output = "linktest.$$";
    my $optarg = "-l $linktest_level -o $output";
    
    print STDOUT "Running 'run_linktest.pl $optarg -e $pid/$eid'\n";
    if (system("$tbdir/run_linktest.pl $optarg -e $pid/$eid") != 0) {
	system("cat $output")
	    if (-r $output);
	
	print STDERR "*** WARNING: ".
	             "Linktest run returned non-zero status!\n";
	
	SENDMAIL("$user_name <$user_email>",
		 "Linktest Failure: $pid/$eid",
		 "Failure in linktest (level $linktest_level); ".
		 "returned non-zero status",
		 "$user_name <$user_email>",
		 "Cc: $expt_head_name <$expt_head_email>\n".
		 "Cc: $TBOPS",
		 ($output));
    }
}

#
# Gather stats. 
#
if ($inout eq "in") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPIN, 0);
}
elsif ($inout eq "out") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPOUT, 0,
		    ($idleswap ? TBDB_STATS_FLAGS_IDLESWAP() : 0));
}
elsif ($inout eq "modify") {
    GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPMODIFY, 0);
}
# Old accounting info.
TBSetExpSwapTime($pid, $eid);

#
# Set the swapper uid on success only, and *after* gathering swap stats!
#
TBExptSetSwapUID($pid, $eid, $dbuid);

#
# In batch mode, just exit without sending email or unlocking. The
# batch daemon will take care of that.
#
if ($batch) {
    exit(0);
}

#
# Clear the log file so the web page stops spewing. 
#
if (defined($logname)) {
    TBExptCloseLogFile($pid, $eid);
}

#
# Must unlock before exit.
#
TBUnLockExp($pid, $eid);

#
# Since the swap completed, clear the cancel flag. This must be done
# after we change the experiment state (above). 
#
TBSetCancelFlag($pid, $eid, EXPTCANCEL_CLEAR);

print "Swap Success!\n";

#
# Send email notification to user.
#
my $message =
    "Experiment $eid in project $pid has been ";

if ($inout eq "out" && ($idleswap || $autoswap || $force) ) {
    $message .= "forcibly swapped out by\nEmulab";
    if ($idleswap) {
	$message .= " because it was idle for too long (Idle-Swap).\n".
	  "(See also the Idle-Swap info in \n".
	  "$TBDOCBASE/docwrapper.php3?docname=swapping.html )\n";
    } elsif ($autoswap) {
	$message .= " because it exceeded its Maximum Duration.\n".
	  "(See also the Max. Duration info in \n".
	  "$TBDOCBASE/docwrapper.php3?docname=swapping.html )\n";
    } elsif ($force) {
	$message .= ". (See also our Node Usage Policies in \n".
	  "$TBDOCBASE/docwrapper.php3?docname=swapping.html )\n";
    }
}
else {
    $message .= "$action.\n";
}

if ($inout eq "in") {
    # Add the swap settings...
    $message .="\nCurrent swap settings:\n$swapsettings";
}

$message .=
    "\n".
    "Appended below is the output. If you have any questions or comments,\n" .
    "please include the output in your message to $TBOPS\n";

SENDMAIL("$user_name <$user_email>",
	 "Experiment $pid/$eid \u$action",
	 $message,
	 ($idleswap ? $TBOPS : "$user_name <$user_email>"),
	 "Cc:  $expt_head_name <$expt_head_email>\n".
	 "Bcc: $TBLOGS",
	 (($inout eq "restart") ? ($logname) :
	  (($repfile, $logname), (defined($modnsfile) ? ($modnsfile) : ()))));

exit 0;

sub fatal($)
{
    my($mesg) = $_[0];

    print STDOUT "*** $0:\n".
	         "    $mesg\n";

    #
    # Gather stats. 
    #
    if ($inout eq "in") {
	GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPIN, $errorstat);
    }
    elsif ($inout eq "out") {
	GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPOUT, $errorstat);
    }
    elsif ($inout eq "modify") {
	GatherSwapStats($pid, $eid, $dbuid, TBDB_STATS_SWAPMODIFY, $errorstat);
    }

    #
    # Clear backup state since not needed anymore; experiment is toast. 
    # 
    if ($inout eq "modify") {
	TBExptClearBackupState($pid, $eid);
    }

    #
    # If hosed, we entirely terminate the experiment.
    #
    if ($modifyHosed) {
	#
	# Note: $estate is indeed still set appropriately!
	#
	if ($estate eq EXPTSTATE_ACTIVE) {
	    print "Running 'tbswap out -force $pid $eid'\n";
	    if (system("$tbdir/tbswap out -force $pid $eid") != 0) {
		print "tbswap out failed!\n";
	    }
	}

	print "Running 'tbend -force $pid $eid'\n";
	if (system("$tbdir/tbend -force $pid $eid") != 0) {
	    print "tbend failed!\n";
	}
	# Must override since we are so badly hosed. 
	$termswapstate = EXPTSTATE_TERMINATED;
    }

    # Copy over the log files so the user can see them.
    system("/bin/cp -Rfp $workdir/ $userdir/tbdata");

    # Set proper state, which is typically the way we came in.
    SetExpState($pid, $eid, $termswapstate);

    #
    # In batch mode, exit without sending the email or unlocking. The
    # batch daemon will take care of that.
    #
    if ($batch) {
	exit($errorstat);
    }

    #
    # Clear the log file so the web page stops spewing.
    #
    if (defined($logname)) {
	TBExptCloseLogFile($pid, $eid);
    }

    # Unlock and reset state to its terminal value.
    TBUnLockExp($pid, $eid);

    #
    # Clear the cancel flag now that the operation is complete. Must be done
    # after we change the experiment state (above).
    #
    TBSetCancelFlag($pid, $eid, EXPTCANCEL_CLEAR);

    #
    # Send a message to the testbed list. Append the logfile.
    #
    SENDMAIL("$user_name <$user_email>",
	     "Swap ${inout} Failure: $pid/$eid",
	     $mesg . "\n\n" .
	     "Please look at the log below to see what happened. If the error\n".
	     "resulted from a lack of resources (not enough nodes), you can\n".
	     "use this web page to get a summary of free nodes:\n\n".
	     "  ${TBBASE}/nodecontrol_list.php3\n".
	     "\n".
	     "Please do not try again until you see enough nodes free.",
	     ($idleswap ? $TBOPS : "$user_name <$user_email>"),
	     "Cc:  $expt_head_name <$expt_head_email>\n".
	     "Cc:  $TBOPS",
	     (($logname), (defined($modnsfile) ? ($modnsfile) : ())));

    if ($modifyHosed) {
	#
	# Copy off the workdir to the user directory, Then back up both of
	# them for post-mortem debugging.
	#
	system("/bin/cp -Rfp $workdir/ $userdir/tbdata");
	system("/bin/rm -rf  ${workdir}-failed");
	system("/bin/mv -f   $workdir ${workdir}-failed");
	system("/bin/rm -rf  ${userdir}-failed");
	system("/bin/mv -f   $userdir ${userdir}-failed");
	TBExptDestroy($pid, $eid);
    }

    exit($errorstat);
}