#!/bin/bash

report()
{
	[[ -n "$SKIP" ]] && exit

	echo -en "$OBJ\tDID_DEEP_FIND=${DID_DEEP_FIND}\t"
	if [[ -n "$ERROR" ]] ; then
		echo "$ERROR"
	else
		echo "$KOBJFILE"
	fi
}

die()
{
	ERROR="${1// /_}"
	exit 1
}

# From kpatch-build
filter_parent_obj()
{
  local dir="${1}"
  local file="${2}"

  grep -v "\.mod\.cmd$" | grep -Fv "${dir}/.${file}.cmd"
}

# From kpatch-build
find_parent_obj() {
	dir="$(dirname "$1")"
	absdir="$(readlink -f "$dir")"
	pwddir="$(readlink -f .)"
	pdir="${absdir#$pwddir/}"
	file="$(basename "$1")"
	grepname="${1%.o}"
	grepname="$grepname\\.o"
	if [[ "$DEEP_FIND" -eq 1 ]]; then
		DID_DEEP_FIND=1
		num=0
		if [[ -n "$last_deep_find" ]]; then
			parent="$(grep -lw -e "$grepname" -e " $file" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | head -n1)"
			num="$(grep -lw -e "$grepname" -e " $file" "$last_deep_find"/.*.cmd | filter_parent_obj "${pdir}" "${file}" | wc -l)"
		fi
		if [[ "$num" -eq 0 ]]; then
			parent="$(find . -name ".*.cmd" -print0 | xargs -0 grep -lw "$grepname" | filter_parent_obj "${pdir}" "${file}" | cut -c3- | head -n1)"
			num="$(find . -name ".*.cmd" -print0 | xargs -0 grep -lw "$grepname" | filter_parent_obj "${pdir}" "${file}" | wc -l)"
			[[ "$num" -eq 1 ]] && last_deep_find="$(dirname "$parent")"
		fi
	else
		parent="$(grep -lw -e "$grepname" -e " $file" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | head -n1)"
		num="$(grep -lw -e "$grepname" -e " $file" "$dir"/.*.cmd | filter_parent_obj "${dir}" "${file}" | wc -l)"
	fi

	[[ "$num" -eq 0 ]] && PARENT="" && return
	[[ "$num" -gt 1 ]] && ERROR_IF_DIFF="two parent matches for $1"

	dir="$(dirname "$parent")"
	PARENT="$(basename "$parent")"
	PARENT="${PARENT#.}"
	PARENT="${PARENT%.cmd}"
	[[ $dir != "." ]] && PARENT="$dir/$PARENT"
	[[ ! -e "$PARENT" ]] && die "ERROR: can't find parent $PARENT for $1"
}

# From kpatch-build
find_kobj() {
	arg="$1"
	KOBJFILE="$arg"
	DEEP_FIND=0
	DID_DEEP_FIND=0
	ERROR_IF_DIFF=
	while true; do
		find_parent_obj "$KOBJFILE"
		[[ -n "$PARENT" ]] && DEEP_FIND=0
		if [[ -z "$PARENT" ]]; then
			[[ "$KOBJFILE" = *.ko ]] && return
			case "$KOBJFILE" in
				*/built-in.o|\
				*/built-in.a|\
				arch/x86/lib/lib.a|\
				arch/x86/kernel/head*.o|\
				arch/x86/kernel/ebda.o|\
				arch/x86/kernel/platform-quirks.o|\
				lib/lib.a)
					KOBJFILE=vmlinux
					return
			esac
			if [[ "$DEEP_FIND" -eq 0 ]]; then
				DEEP_FIND=1
				continue;
			fi
			die "invalid ancestor $KOBJFILE for $arg"
		fi
		KOBJFILE="$PARENT"
	done
}

trap report EXIT INT TERM HUP

OBJ="${1/.\//}"

# From kpatch-cc
case "$OBJ" in
	*.mod.o|\
	*built-in.o|\
	*built-in.a|\
	vmlinux.o|\
	.tmp_kallsyms1.o|\
	.tmp_kallsyms2.o|\
	init/version.o|\
	arch/x86/boot/version.o|\
	arch/x86/boot/compressed/eboot.o|\
	arch/x86/boot/header.o|\
	arch/x86/boot/compressed/efi_stub_64.o|\
	arch/x86/boot/compressed/piggy.o|\
	kernel/system_certificates.o|\
	arch/x86/vdso/*|\
	arch/x86/entry/vdso/*|\
	drivers/firmware/efi/libstub/*|\
	arch/powerpc/kernel/prom_init.o|\
	arch/powerpc/kernel/vdso64/*|\
	arch/s390/boot/*|\
	arch/s390/purgatory/*|\
	arch/s390/kernel/vdso64/*|\
	lib/*|\
	scripts/*|\
	arch/x86/boot/*|\
	arch/x86/tools/*|\
	.*.o|\
	*/.lib_exports.o)
		SKIP=1
		exit
		;;
	*.o)
		find_kobj "$OBJ"
		exit
		;;
	*)
		SKIP=1
		exit
		;;
esac