#!/usr/bin/perl5

# usage: mrtg-getinfo-intr <interrupt-number>
#
# <interrupt-number>
#     interrupt number to monitor (first field in /proc/interrupts)
#
# This script polls information from some /proc files and outputs the polled
# information in a format usable by mrtg. It can also function as a required
# file, in which case it will gather the data from /proc but not output
# anything to stdout.
#
# This script is derived from mrtg-getinfo-mem

open(INTRINFO, "/proc/interrupts") || die("/proc/interrupts: $!\nstopped");
while (<INTRINFO>) {
   if (/^\s*(\d+):\s*(\d+) (.) (.*)\s*\n/) { # This should always be the case
      $interrupts[$1] = $2;
      $flag[$1] = $3;
      # We may have two interrupts with the same name (e.g., 3c509)
      # Set up a "pointer" so we can iteratively access both
      if (defined $p{$4}) {
	 $q{$4} += 1;
      } else {
	 $p{$4} = $q{$4} = 1;
      }
      # We will also need to set up a pseudo 2-d array
      $number{"$4,$q{$4}"} = $1;
   }
}
close(INTRINFO);

open(UPTIME, "/proc/uptime") || die("/proc/uptime: $!\nstopped");
<UPTIME> =~ /^(\d+)/;
$uptime = $1;
close(UPTIME);

open(HOSTNAME, "/proc/sys/kernel/hostname") || die("/proc/sys/kernel/hostname: $!\nstopped");
$hostname = <HOSTNAME>;
chomp $hostname;
close(HOSTNAME);

# See if we are being require'd from another perl5 program.
# If we are, we expect caller(0) to return non-null information;
# in particular, $subroutine should be "(eval)" (by empirical observation).

($package, $filename, $line, $subroutine, $hasargs, $wantargs) = caller(0);
if (! defined $subroutine) {
   for ($i = 0; $i < 2; $i += 1) {
      if ($i <= $#ARGV) {
	 my $j = $ARGV[$i];
	 if ($j =~ /^\d+$/) {
	    printf("%d\n", $j >= 0? $interrupts[$j]: 0);
	 } else {
	    if (defined $number{"$j,$p{$j}"}) {
	       printf("%d\n", $interrupts[$number{"$j,$p{$j}"}]);
	       $p{$j} += 1;
	    } else {
	       printf("0\n");
	    }
	 }
      } else {
	 printf("0\n");
      }
   }
   if ($uptime >= 86400) {
      my($days) = int($uptime/86400);
      printf("%d day%s, ", $days, $days == 1? "": "s");
   }
   printf("%02d:%02d:%02d\n", ($uptime/3600)%24, ($uptime/60)%60, $uptime%60);
   printf("%s\n", $hostname);
}
1;