#!/usr/bin/perl
#
#Usage:  check-tsm-schedule <next_wake_hour:next_wake_minute>
#e.g. check-tsm-schedule 8:00
#
# Note maths desktops typically backup on Thursday nights, 
# starting somewhere between 18:30 and 23:45
# Logfile typically has an updated entry every 12 hours when machine is on

use Time::Local;

if ( ! defined $ARGV[0] ) {
    print "You need to provide a time for start of next wake period\n";
    exit;
}

#check if there is a dsmc or dsmcad process otherwise exit cleanly
if ( `ps ax | grep -v grep | grep dsmc` ) {
    print "TSM process present\n";
} else {
    print "No TSM process, exiting\n";
    exit 0
}

#TSM schedule backup log file
$logfile='/var/log/dsmsched.log';
#amount of time to allow for a backup to start and then end too
$backup_buffer=60*60;
#time of next wakeup read in from command line
($next_wake_hour,$next_wake_minute) = split(/:/,$ARGV[0],2);

#get the current time in two ways
$now_in_secs=time();
@now = localtime();

$wake_secs_from_day_start=($next_wake_hour*60+$next_wake_minute)*60;
$now_secs_from_day_start=($now[2]*60+$now[1])*60+$now[0];
$seconds_to_next_wakeup = $wake_secs_from_day_start - $now_secs_from_day_start;
if ($wake_secs_from_day_start < $now_secs_from_day_start) {
    #then wake up is at least tomorrow so adjust
    $seconds_to_next_wakeup = 24*60*60 + $seconds_to_next_wakeup;
}
print "Seconds to next wake up >= $seconds_to_next_wakeup\n";

$logline=`grep "Server Window Start" $logfile | tail -1`;
if ( $logline eq '' ) {
    print "TSM client is running but backup start time not defined\n";
    exit 0;
}
$logline =~ /.*Start:\s*(\d*):(\d*):(\d*) on (\d*)-(\d*)-(\d*)/;
$schedule_time_secs=timelocal($3,$2,$1,$4,$5-1,$6);
$seconds_to_scheduled_backup=$schedule_time_secs-$now_in_secs;
print "Seconds to next backup = $seconds_to_scheduled_backup\n";

if ($seconds_to_scheduled_backup < -$backup_buffer ) {
#NOTE: don't strictly need this buffer step but it can be useful
#backup should have started more than buffer period ago and hence finished so
#can proceed with a shutdown
    print "Backup start time passed more than buffer $backup_buffer seconds ago\n";
    exit 0;
} elsif ( $seconds_to_scheduled_backup < 0 ) {
#backup should have started but we are in the buffer period so 
#it may actually not have started (TSM has a 15 minute slot to 
#start in after scheduled start time) or still be running
    $logline=`grep "SCHEDULEREC OBJECT END" $logfile | tail -1`;
    $logline =~ /^(\d*)-(\d*)-(\d*) (\d*):(\d*):(\d*) --- /;
    $backup_end_time_secs=timelocal($6,$5,$4,$1,$2-1,$3);
    if ($backup_end_time_secs > $schedule_time_secs && $schedule_time_secs < $now) {
	print "Backup start time has passed, we are in the buffer period but backup confirmed completed\n";
	exit 0;
    } else {
	print "Backup start time has passed, we are in the buffer period and backup not confirmed completed\n";
	exit 1;
    }
} elsif ( $seconds_to_scheduled_backup > $seconds_to_next_wakeup ) {
    #will wake up automatically before next backup so safe to go off now
    print "No backup scheduled within remainder of this shutdown period\n";
    exit 0;
} else {
#backup has not occurred and will occur within this period so stay on for now
    print "Backup scheduled to start within remainder of this shutdown period\n";
    exit 1;
}