#!/usr/bin/perl

###########################################################################
# Filename: ksamp
# Coder: Tuan Pham
# Description: Reports behavior of the Linux kernel.
# default option:
# 	o CPU type and model
# 	o Kernel version
# 	o Amount of time since the file system was lasted booted in
# 	dd-hh-mm-ss
# -s:
# 	o Same as default option
# 	o The amount of time the CPU has spent in user mode, system mode,
# 	and the amount of the system was idle
# 	o The number of disk request made on system
# 	o The number of context switches the kernel has performed
# 	o The time at which the system was last boot
# 	o The number of processes that have been created since the system
# 	was boot
#

main();

sub main()
{
	kernel();	# call the default
	if ( "-s" eq shift(@ARGV) )
	{
		#print "option -s is detected\n";
		sysinfo();
	}
}

###############################################
# kernel()
# prints the default output of the kernel info
# there are a lot of system calls, hm....

sub kernel()
{
	# parse the cpu model name
	my @A_LINE=split(":",`cat /proc/cpuinfo | grep 'model name'`);
	my $CPU_MODEL=@A_LINE[1];
	chomp $CPU_MODEL;	# chop off the \n char at the end

	# parse the vendor_id
	@A_LINE=split(":",`cat /proc/cpuinfo | grep 'vendor_id'`);
	$CPU_ID=@A_LINE[1];
	chomp $CPU_ID;

	# parse the 
	my $CPU_SPEED=`cat /proc/cpuinfo | grep 'cpu MHz' | awk '{print \$4}'`;	# note: \$
	chomp $CPU_SPEED;
	
	my $KERNEL_VERSION=`cat /proc/version | awk '{print \$3}'`;		# get version number
	chomp $KERNEL_VERSION;
	
	# parse the uptime
	my $UP_TIME=toDate(int (`cat /proc/uptime | awk '{print \$1}'`));

	print "CPU model:$CPU_MODEL\n";
	print "CPU type:$CPU_ID $CPU_SPEED Mhz\n";
	print "Kernel version: $KERNEL_VERSION\n";
	print "Uptime: $UP_TIME\n\n";
}


##############################################
# sysinfo()
# prints the system info for -s

sub sysinfo()
{
	my @A_LINE;
	my $USR_MODE, $SYS_MODE, $IDLE_MODE;	# usr, sys, idle
	my $IO_REQ;				# disk i/o request
	my $CONT_SW;				# context switch
	my $LAST_BOOT;				# boot date + uptime = current time
	my $PROC;				# number of processes that have been created

	# parse the usr, sys, idle mode
	@A_LINE=split(" ",`cat /proc/stat | grep 'cpu'`);
	$USR_MODE=toDate(@A_LINE[1]);
	$SYS_MODE=toDate(@A_LINE[3]);
	$IDLE_MODE=toDate(int(@A_LINE[4]/100));

	#parse the disk request
	@A_LINE=split(":",`cat /proc/stat | grep 'disk_io' | awk '{print \$3}'`);
	@A_LINE=split(",",@A_LINE[1]);
	$IO_REQ=@A_LINE[0];
	$IO_REQ=~s/\(//;
	
	#parse the context switch
	$CONT_SW=`cat /proc/stat | grep 'ctxt' | awk '{print \$2}'`;
	chomp $CONT_SW;
	
	#parse the boot time
	my $BTIME=`cat /proc/stat | grep 'btime' | awk '{print \$2'}`;
	($sec,$min,$hr,$mday,$mon,$yr,$wd,$ydat,$isdst)=gmtime($BTIME);	# boot time from 1970, convert it GMT
	$temp=int(1900+$yr);
	$LAST_BOOT="$mday-$mon-$temp";
	#$LAST_BOOT=$BTIME;
	
	#parse number of processes
	$PROC=`cat /proc/stat | grep 'processes' | awk '{print \$2'}`;
	chomp $PROC;
	
	print"\n";
	print "System info:\n";
	print "\tUser mode: $USR_MODE\n";
	print "\tSystem mode: $SYS_MODE\n";
	print "\tIdle mode: $IDLE_MODE\n";
	print "\tDisk request: $IO_REQ\n";
	print "\tContext switch: $CONT_SW\n";
	print "\tLast boot: $LAST_BOOT\n";
	print "\tNumber of processes: $PROC\n";
}

##############################################
# toDate(para1)
# convert from seconds to dd-hh-mm-ss
sub toDate()
{
	my $DAYS, $HOURS, $MINUTES, $SECONDS, $REST;
	$DAYS=int ($_[0]/86400);	# 3600sec*24hrs, get # days
	$REST=$_[0]%86400;		# get the remainder
	$HOURS=int ($REST/3600);	# get hrs
	$REST=$REST%3600;		# get the remainder
	$MINUTES=int ($REST/60);	# get mins
	$SECONDS=$REST%60;		#
	return "$DAYS\d-$HOURS\h-$MINUTES\m-$SECONDS\s";
}