fuzz/llvm: add `common.sh` for llvm fuzzers

#!/usr/bin/env bash

#  SPDX-License-Identifier: BSD-3-Clause

#  Copyright (C) 2022 Intel Corporation

#  All rights reserved.

#

# Store pids of parallel fuzzer tests

pids=()

function cleanup() {

	rm -rf "$@"

	# Make sure that there is no process left hanging

	kill -9 "${pids[@]}" || :

}

function get_testn() {

	local fuzz_num=$1

	local mem_size=$2

	local nproc

	nproc=$(nproc)

	# Choose lower value, best case scenario is one test per core

	local testn=$((fuzz_num < nproc ? fuzz_num : nproc))

	export HUGEMEM=$((mem_size * testn))

	setup

	TESTN=$testn

}

function start_llvm_fuzz_all() {

	local testn=$1    # Number of test to run in parallel

	local fuzz_num=$2 # Number of fuzzer tests

	local time=$3     # Time available for all fuzzers

	local core

	# Calculate time for a single test and multiply it by number

	# of test execute in parallel and round it up to 1 sek per test

	timen=$(printf %d $(((time / fuzz_num) * testn)))

	timen=$((timen == 0 ? 1 : timen))

	for ((i = 0; i < fuzz_num; i++)); do

		core=$(printf "0x%x" $((0x1 << (i % testn))))

		start_llvm_fuzz $i $timen $core &> $output_dir/llvm/llvm_"$FUZZER"_$i.txt &

		pids+=($!)

		# Wait for processes to finish

		if (((i + 1) % testn == 0 || fuzz_num - i - 1 == 0)); then

			(

				sleep $((timen * 10 + 100))

				echo "Timeout $time"

				exit 1

			) &

			timeout_pid=$!

			for pid in "${pids[@]}"; do

				wait $pid

			done

			kill $timeout_pid || :

			pids=()

		fi

	done

}

function start_llvm_fuzz_short() {

	local fuzz_num=$1

	local time=$2

	for ((i = 0; i < fuzz_num; i++)); do

		start_llvm_fuzz $i $time 0x1

	done

}