View of /FigCommon/lwc_postprocess.pl

#
# This script is invoked after a lightweight code update has completed.
#
# It is used to kick the services scripts if they are running so that
# they pick up any new code.
#
# In addition, I anticipate this being the place to hook any per-module functionality
# that might need a post-lwc step. The scheme would probably be a module writes
# a file into FIG/var/lwc_post.d when it makes, and this script executes all of those scripts.
#

use FIG_Config;
use strict;
use Errno qw(EEXIST EINVAL ESRCH EPERM);

kick_services();

exit;

sub kick_services
{
    #
    # This is more grossness because we don't have a generalized mechanism
    # for registering services to be stopped and started. Must be coordinated
    # with the startup/shutdown code in FigKernelScripts/start_services.pl and
    # stop_services.pl.
    #

    #
    # Check to see if one of the services is running. If it is, invoke
    # stop_services and start_services. Otherwise, don't bother as we
    # don't want to start up services if they are currently stopped.
    #
    # We need to also check that the service is running as the same
    # user that we are running as. 
    #

    my $pid_file  = "$FIG_Config::fig_disk/config/seed_registration.pid";
    if (not open(FH, "<$pid_file"))
    {
	#
	# Not there. just return.
	#

	return;
    }

    my $pid = <FH>;
    chop $pid;

    #
    # Try a kill with signal 0 to see if the process exists and if we might
    # be able to kill it.
    #

    if (kill(0, $pid) == 1)
    {
	#
	# We can do it. Do a stop/start services.
	#
	my $rc = system("$FIG_Config::bin/stop_services");
	if ($rc != 0)
	{
	    warn "lwc_postprocess: stop_services failed with rc=$rc\n";
	}
	else
	{
	    #
	    # If we're running from a CGI, close  STDIN and STDOUT to
	    # keep things from hanging.
	    #

	    if (exists($ENV{SERVER_NAME}))
	    {
		close(STDIN);
		close(STDOUT);
	    }
	       
	    my $rc = system("$FIG_Config::bin/start_services");
	    if ($rc != 0)
	    {
		warn "lwc_postprocess: start_services failed with rc=$rc\n";
	    }
	}
    }
    else
    {
	if ($! == ESRCH)
	{
	    warn "lwc_postprocess: service process not found, not restarting services.\n";
	}
	elsif ($! == EPERM)
	{
	    warn "lwc_postprocess: services running as a different user, not restarting services.\n";
	}
	else
	{
	    warn "lwc_postprocess: Unknown error probing for existing service: $!\n";
	}
    }

}