RROrg-rr/files/initrd/opt/rr/calc_run_size.sh
2025-03-06 17:02:25 +08:00

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#!/usr/bin/env bash
#
# Copyright (C) 2022 Ing <https://github.com/wjz304>
#
# This is free software, licensed under the MIT License.
# See /LICENSE for more information.
#
# Calculate the amount of space needed to run the kernel, including room for
# the .bss and .brk sections.
#
# Usage:
# objdump -h a.out | sh calc_run_size.sh
NUM='\([0-9a-fA-F]*[ \t]*\)'
OUT=$(sed -n 's/^[ \t0-9]*.b[sr][sk][ \t]*'"${NUM}${NUM}${NUM}${NUM}"'.*/0x\1 0x\4/p')
if [ -z "${OUT}" ]; then
echo "Never found .bss or .brk file offset" >&2
exit 1
fi
read -r sizeA offsetA sizeB offsetB <<<"$(echo ${OUT} | awk '{printf "%d %d %d %d", strtonum($1), strtonum($2), strtonum($3), strtonum($4)}')"
runSize=$((offsetA + sizeA + sizeB))
# BFD linker shows the same file offset in ELF.
if [ "${offsetA}" -ne "${offsetB}" ]; then
# Gold linker shows them as consecutive.
endSize=$((offsetB + sizeB))
if [ "${endSize}" -ne "${runSize}" ]; then
printf "sizeA: 0x%x\n" ${sizeA} >&2
printf "offsetA: 0x%x\n" ${offsetA} >&2
printf "sizeB: 0x%x\n" ${sizeB} >&2
printf "offsetB: 0x%x\n" ${offsetB} >&2
echo ".bss and .brk are non-contiguous" >&2
exit 1
fi
fi
printf "%d\n" ${runSize}
exit 0