#!/bin/bash

#    Copyright (C) 2023  Pasha <pasha@bell01.com>
#
#    This program is free software: you can redistribute it and/or modify
#    it under the terms of the GNU General Public License as published by
#    the Free Software Foundation, either version 3 of the License, or
#    (at your option) any later version.
#
#    This program is distributed in the hope that it will be useful,
#    but WITHOUT ANY WARRANTY; without even the implied warranty of
#    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
#    GNU General Public License for more details.
#
#    You should have received a copy of the GNU General Public License
#    along with this program.  If not, see <https://www.gnu.org/licenses/>.

show_version() {
    echo "0.1a"
    exit 1
}

show_usage() {
    echo "Usage: $0 bpf_program_path container_id"
    echo "example: $0 /usr/sbin/execsnoop-bpfcc \$(docker inspect --format=\"{{.Id}}\" 119cb41a9e09)"

    echo "         $0 /usr/sbin/execsnoop-bpfcc \$(kubectl get pods -o jsonpath='{range .items[*].status.containerStatuses[*]}{.containerID}{\"\n\"}{end}' --field-selector metadata.name=test-deployment-7f456874f4-mxjg4 | cut -b 10-)"
    exit 1
}

if [[ "$1" == "-v" ]]; then
   show_version
fi

if [ -z "$1" ] || [ -z "$2" ]; then
   show_usage
fi

bpf_prog_path=$1
containerid=$2

echo "creating bpf map"

BPF_FILE=/sys/fs/bpf/$containerid
if [ -f "$BPF_FILE" ]; then
    echo "error bpf map exists."
    echo "please unmap or remove \"$BPF_FILE\" and try again."
    exit 1
fi

echo $BPF_FILE

/usr/sbin/bpftool map create $BPF_FILE type hash key 8 value 8 entries 128 name cgroupset flags 0

cgroupid=$(containercgroup id $containerid)
if [ -z "$cgroupid" ]
then
    echo "invalid container id"
    echo "removing bpf map"
    rm $BPF_FILE
    exit 1
fi

echo "cgroupid: $cgroupid"
/usr/sbin/bpftool map update pinned $BPF_FILE key hex $cgroupid value hex 00 00 00 00 00 00 00 00 any

$bpf_prog_path --cgroup $BPF_FILE

echo "removing bpf map"
rm $BPF_FILE