systemd/tools/debug-sd-boot.sh

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#!/usr/bin/env bash
# SPDX-License-Identifier: LGPL-2.1-or-later
set -e
if [[ $# -lt 2 ]]; then
echo "Usage: ${0} TARGET INPUT [GDBSCRIPT]"
echo "Debug systemd-boot/stub in QEMU."
echo
echo "TARGET should point to the EFI binary to be examined inside the"
echo "build directory (systemd-boot\$ARCH.efi or linux\$arch.efi.stub)."
echo
echo "INPUT should point to the QEMU serial output pipe. This is used to"
echo "extract the location of the symbols. For this to work, QEMU must"
echo "be run with '-s -serial pipe:PATH'. Note that QEMU will append"
echo ".in/.out to the path, while this script expects the out pipe directly."
echo
echo "If GDBSCRIPT is empty, gdb is run directly attached to the boot"
echo "loader, otherwise a script is generated in the given path that allows"
echo "attaching manually like this:"
echo " (gdb) source GDBSCRIPT"
echo " (gdb) target remote :1234"
echo
echo "Example usage:"
echo " mkfifo /tmp/sdboot.{in,out}"
echo " qemu-system-x86_64 [...] -s -serial pipe:/tmp/sdboot"
echo " ./tools/debug-sd-boot.sh ./build/src/boot/efi/systemd-bootx64.efi \\"
echo " /tmp/sdboot.out"
exit 1
fi
binary=$(realpath "${1}")
if [[ "${1}" =~ systemd-boot([[:alnum:]]+).efi ]]; then
target="systemd-boot"
symbols=$(realpath "${1%efi}elf")
elif [[ "${1}" =~ linux([[:alnum:]]+).efi.stub ]]; then
target="systemd-stub"
symbols=$(realpath "${1%efi.stub}elf.stub")
else
echo "Cannot detect EFI binary '${1}'."
exit 1
fi
case "${BASH_REMATCH[1]}" in
ia32) arch="i386";;
x64) arch="i386:x86-64";;
aa64) arch="aarch64";;
arm|riscv64) arch="${BASH_REMATCH[1]}";;
*)
echo "Unknown EFI arch '${BASH_REMATCH[1]}'."
exit 1
esac
# system-boot will print out a line like this to inform us where gdb is supposed to
# look for .text and .data section:
# systemd-boot@0x0,0x0
while read -r line; do
if [[ "${line}" =~ ${target}@(0x[[:xdigit:]]+),(0x[[:xdigit:]]+) ]]; then
text="${BASH_REMATCH[1]}"
data="${BASH_REMATCH[2]}"
break
fi
done < "${2}"
if [[ -z "${text}" || -z "${data}" ]]; then
echo "Could not determine text and data location."
exit 1
fi
if [[ -z "${3}" ]]; then
gdb_script=$(mktemp /tmp/debug-sd-boot.XXXXXX.gdb)
trap 'rm -f "${gdb_script}"' EXIT
else
gdb_script="${3}"
fi
echo "file ${binary}
add-symbol-file ${symbols} ${text} -s .data ${data}
set architecture ${arch}" > "${gdb_script}"
if [[ -z "${3}" ]]; then
gdb -x "${gdb_script}" -ex "target remote :1234"
else
echo "GDB script written to '${gdb_script}'."
fi