#!/bin/sh
#
# dstack: A simple pstack replacement
# Copyright (c) 2012 Daniel van Vugt <vanvugt@gmail.com>
#

if [ -z "$1" ]; then
	echo "dstack 1.0  Copyright (c) 2012 Daniel van Vugt <vanvugt@gmail.com>"
	echo "Usage: $0 <process-name-or-pid>"
	return
fi

pid=`pidof $1`
if [ -z "$pid" ]; then
	pid="$1"
fi
if [ -d "/proc/$pid" ]; then
	lines=`cat /proc/$pid/maps` || {
		echo "Error: Insufficient permission to access process $pid."
		echo "Try: sudo $0 $*"
		return
	}
else
	echo "Error: $pid is not a process name or a process ID."
	return
fi

echo "Process ID:   $pid"

progname=`awk '{print $2}' "/proc/$pid/stat" | sed 's/[()]//g'`
progpath=`readlink /proc/$pid/exe`
threads=`awk '{print $20}' "/proc/$pid/stat"`

echo "Program name: $progname"
echo "Program path: $progpath"
echo "Thread count: $threads"
echo ""

script="/tmp/dstackscript$$"
echo "echo Dstack of $progname pid $pid ($progpath)\\\\n" > "$script"

t=1
while [ "$t" -le "$threads" ]; do
	echo "echo \\\\n" >> "$script"
	echo "thread $t" >> "$script"
	echo "bt" >> "$script"
	t=`expr $t + 1`
done

echo quit >> "$script"
echo yes >> "$script"

gdb -q -x "$script" "$progpath" "$pid" | grep -A999 "Dstack of "

rm -f "$script"