#! /bin/sh
set -u
set -e

INPATH="$1"
INBASEPATH="${INPATH%.*}"
#       mangle such that no two names conflict (a/b/c and a/b.c conflicting would be no fun)
#OUTNAME="$(echo "$INBASEPATH" | sed 's/\./../g' | sed 's/\//._/g')"
OUTNAME="src._kernel._main"
echo -n "[*] Building '$INPATH' to 'tmp/$OUTNAME'... "
gcc -T linker.ld -m32 -Wl,--build-id=none -nostartfiles -nostdlib -ffreestanding $INPATH -o "tmp/$OUTNAME".o
echo " OK!"
echo -n "[+] Start address is... "
BIN_START=$(objdump tmp/src._kernel._main.o -f | grep start | cut -b 15-)
echo "$BIN_START"
# this actually writes three extra nulls, not sure why...
echo "$BIN_START" | xxd -r - | od -t x --endian=little | head | xxd -r - > "bin/$OUTNAME".bin
echo -n "[+] Stripping unnecessary sections... "
objcopy -R .note.gnu.build-id -R .comment -O binary "tmp/$OUTNAME".o "tmp/converted_$OUTNAME".bin
echo " OK!"

echo -n "[+] Joining kernel and start address... "
# adjust for the three extra nulls above
dd if="tmp/converted_$OUTNAME".bin of="bin/$OUTNAME".bin seek=4 oflag=seek_bytes conv=notrunc 2>/dev/null
echo " OK!"
#rm "tmp/$OUTNAME".o