frisbeehelper.in 7.09 KB
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#!/usr/bin/perl -wT
#
# EMULAB-COPYRIGHT
# Copyright (c) 2011 University of Utah and the Flux Group.
# All rights reserved.
#
use strict;
use Getopt::Std;
use Sys::Syslog;
use English;
use Socket;
use Errno;

#
# This is a compatibility shim for the pre-mfrisbeed frisbee world.
#
# It can be used to start or kill a frisbeed via the master server.
#

#
# This also kills a running frisbee.
#
sub usage()
{
    print "Usage: $0 [-d] -n nodeid <imageid>\n";
    print "  or\n";
    print "Usage: $0 [-d] -k <imageid>\n";
    print "-n nodeid   Node used for authentication of image access\n";
    print "-k:	       Kill (rather than start) a frisbeed.\n";
    print "-d:	       Print debugging output.\n";
    exit(1);
}
my $optlist  = "dkn:";
my $debug    = 0;
my $killmode = 0;
my $nodeid;

# Configure variables
my $TB		= "@prefix@";

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

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

use lib "@prefix@/lib";
use libdb;
use libtestbed;
use libtblog;
use Node;
use User;
use Image;

# Protos.
sub Fatal($);
sub debug($);

# Defines
my $FRISBEE	= "$TB/sbin/frisbee";
my $PIDDIR	= "/var/run";

#
# Parse command arguments. Once we return from getopts, all that should be
# left are the required arguments.
#
my %options = ();
if (! getopts($optlist, \%options)) {
    usage();
}
if (defined($options{"d"})) {
    $debug = 1;
}
if (defined($options{"k"})) {
    $killmode = 1;
}
if (defined($options{"n"})) {
    $nodeid = $options{"n"};
    if ($nodeid =~ /^([-\w]+)$/) {
	$nodeid = $1;
    } else {
	Fatal("invalid nodeid");
    }
}
usage()
    if (!@ARGV || (!$killmode && !$nodeid));

my $imagename = $ARGV[0];
if ($imagename =~ /^([-\w\.+\/]+)$/) {
    $imagename = $1;
} else {
    Fatal("invalid imagename");
}

#
# Authentication.
#
# Note that an imageid can be a traditional disk image or the pathname
# of a file, the master frisbee server worries about that distinction.
#
# For starting an image server, we provide a node_id which the master
# server can authenticate with. We would also like to make sure the calling
# user has permission to manipulate the node given, but unfortunately we
# are called from tmcd which runs as "nobody". So since this is a temporary
# shim, and we only run on boss where access is limited to authorized users
# or through constrained interfaces, we allow any user to start up a
# daemon for an image.
#
# For killing a server, we don't always have a node context.  In the
# case where we don't, it will be a true image and we can perform an access
# check with respect to the image.
#
# So, the strategy is:
#
#  * If we have a node context, and it is a regular Emulab image,
#    we let the master server worry about whether the node can access
#    the image.  This is the "relaxed" case for tmcd.
#
#  * If we have a node context, but it is not an Emulab image,
#    we check that the user can modify the node, and let the master server
#    worry about the node/user's ability to access the file.
#    We do the user check here because tmcd will never call us to check
#    on a non-image file.
#
#  * If there is no node context, it can only be a "kill" and we check
#    the user's ability to modify the image (if it isn't an image, this
#    check will fail).
#
my ($this_user, $isadmin, $image);

if ($UID) {
    $this_user = User->ThisUser();
    if (!defined($this_user)) {
	# XXX allow unknown user to start a server for a specified node
	if (!$nodeid || $killmode) {
	    Fatal("$UID: not a valid Emulab user");
	}
	$isadmin = 1;
    } else {
	$isadmin = $this_user->IsAdmin();
    }
} else {
    $isadmin = 1;
}

$image = Image->Lookup($imagename);
if (!$image) {
    # If not an Emulab image, we must have a node context to check
    if (!$nodeid) {
	Fatal("$imagename: not a valid Emulab image");
    }
    # We must also have a valid user
    if (!$this_user) {
	Fatal("$UID: not a valid Emulab user");
    }
}

if ($nodeid) {
    my $node = Node->Lookup($nodeid);
    if (!$node) {
	Fatal("$nodeid: no such node");
    }
    if (!$isadmin &&
	!$node->AccessCheck($this_user, TB_NODEACCESS_LOADIMAGE)) {
	Fatal("$nodeid: cannot access node");
    }
} else {
    # must be a kill operation; we checked this above
    # must be a real image; ditto
    # only called this way when deleting an image, so check access accordingly
    if (!$isadmin &&
	!$image->AccessCheck($this_user, TB_IMAGEID_DESTROY)) {
	Fatal("$imagename: no permission to destroy");
    }
}

#
# If it is a real image, we have to construct the proper master server
# imageid for it (pid/imagename), otherwise the given name is treated
# as a filename path.
#
my $imageid;
if ($image) {
    $imageid = $image->pid() . "/" . $image->imagename();
} else {
    $imageid = $imagename;
}

#
# Now we use the frisbee client to contact the master server
# and either request starting of a server or to get back info that
# we can use to kill the server instance.
#
my $cmd = "$FRISBEE -S localhost";
if ($nodeid) {
    $cmd .= " -P $nodeid";
}
if ($killmode) {
    $cmd .= " -Q $imageid";
} else {
    $cmd .= " -F $imageid /dev/null";
}
debug("Invoking: $cmd\n");

#
# Parse the query/get output to get the address/port to either report
# to the user on startup or to use to form a pid file name that we can
# use to kill a running server.
#
my ($addr,$port,$running);
if (!open(FRIS, "$cmd 2>&1 |")) {
    Fatal("frisbee invocation failed!");
}
while (<FRIS>) {
    if (/^error=(.*)$/) {
	if ($1 != 0) {
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	    # For killmode we take an error to mean no daemon is running
	    if ($killmode) {
		$running = 0;
		last;
	    }
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	    Fatal("frisbee returned error=$1");
	}
	next;
    }
    if (/^running=(\d)$/) {
	$running = $1;
	last
	    if ($running == 0);
	next;
    }
    if (/^addr=([\d.]+)$/) {
	$addr = $1;
	next;
    }
    if (/^port=(\d+)$/) {
	$port = $1;
	next;
    }
    if (/: address: ([\d.]+):(\d+)/) {
	$running = 1;
	$addr = $1;
	$port = $2;
	last;
    }
}
close(FRIS);
if ($running && (!$addr || !$port)) {
    Fatal("$imageid: could not determine address/port for server");
}

#
# Starting: just report information
#
if (!$killmode) {
    if (!$running) {
	Fatal("$imageid: could not start server");
    }
    print "Address is $addr:$port\n";
    exit(0);
}

#
# Killing: kill daemon if running
#
if ($running) {
    my $pidfile = "$PIDDIR/frisbeed-$addr-$port.pid";
    if (! -r "$pidfile") {
	debug("no pidfile '$pidfile' found\n");
    } else {
	my $pid = `cat $pidfile`;
	if ($?) {
	    debug("could not open '$pidfile'\n");
	} else {
	    if ($pid =~ /^(\d+)/) {
		$pid = $1;
		if (!kill('TERM', $pid)) {
		    debug("could not kill $imageid process $pid\n");
		} else {
		    print "Killed process $pid\n";
		}
	    } else {
		debug("bogus pid in $pidfile\n");
	    }
	}
    }
}
exit(0);


######################################################################
# Subroutines
######################################################################

# Only print if -d option was given. Also add $$ on the beginning of the
# string, to ease debugging
sub debug($)
{
    my ($msg) = @_;

    print STDERR "$$: $msg"
	if ($debug);
}

sub Fatal($)
{
    my ($msg) = @_;
    
    tbdie("*** $0:\n".
	  "    $msg\n");
}