#!/bin/bash -u
#
# Change into the directory passed as the first parameter, execute the command
# passed as the remaining parameters inside a Linux VM and return the exit
# code of the execution.

WORKING_DIR=$1
shift
COMMAND=$*

BASE_DIR=$(dirname $(realpath $0))
LINUX=${BASE_DIR}/kernel
EXIT_PORT=244

qemu-system-x86_64 \
   -nographic \
   -no-reboot \
   -serial stdio \
   -monitor none \
   -m 2048 \
   -machine pc,accel=tcg,usb=off,dump-guest-core=off \
   -rtc base=utc \
   -boot strict=on \
   -kernel ${LINUX} \
   -append "init=${BASE_DIR}/init working_dir=${WORKING_DIR} command=\"${COMMAND}\" exit_port=${EXIT_PORT}" \
   -fsdev local,id=fsdev-fsRoot,security_model=none,multidevs=remap,path=/ \
   -device virtio-9p-pci,id=fsRoot,fsdev=fsdev-fsRoot,mount_tag=fsRoot \
   -device isa-debug-exit,iobase=${EXIT_PORT},iosize=0x04 \

# Qemu's exit code is the one provided to the isa-debug-exit device, but shifted one bit left.
# Revert the value to the original one.
exit $[$? / 2]