Kill Shell Subprocess Recursively

kspr.sh

#!/bin/bash

# Kill Subprocesses Recursively

RECURSIVE_WARNING_THRESHOLD=20
RECURSIVE_ERROR_THRESHOLD=50

debug(){
        echo "DEBUG: $*"
}

warn(){
        echo "WARNING: $*"
}

error(){
        echo "ERROR: $*" >&2
}

kill_recursively() {
        local PID=$1

        if [ -z $PID ]; then
                error "No PID specified. Returning"
                return;
        fi

        local LAYER=$2

        if [ -z $LAYER ]; then
                LAYER=0
        fi

        debug "Recursive layer: $LAYER"

        if [ $LAYER -gt $RECURSIVE_ERROR_THRESHOLD ]; then
                error "Current recursive layer is over $RECURSIVE_ERROR_THRESHOLD, exiting."
                return;
        fi

        if [ $LAYER -gt $RECURSIVE_WARNING_THRESHOLD ]; then
                warn "Current recursive layer is over threshold $RECURSIVE_WARNING_THRESHOLD"
        fi

        local subprocess=`pgrep -P $PID`

        if [[ -z $subprocess ]]; then
                debug "No more subprocess, committing suicide: $PID"
                # kill -9 $PID
                return;
        fi

        for sp in $subprocess; do
                debug "Looping PID is $sp"
                kill_recursively $sp $(expr $LAYER + 1)
        done;

        debug "Finally commit suicide : $PID"
        # kill -9 $PID
}


ARG_COUNT=$#

debug "Arg count: $ARG_COUNT"

if [ $ARG_COUNT -le 0 ]; then
        error "No PID specified!"
        exit 1
fi

PID=$1

debug "Root PID : $PID"

if [ $PID -le 1 ]; then
        error "Should never kill systemd and its root process!"
        exit 1
fi


kill_recursively $PID