#!/bin/sh

# this script is brutal and verbose, has no tricks and is quite linear, then
# quite easy to deal with
# for the moment, it's hardcoded for a gcc toolchain... BAD! Since now
# gcc is a c++ piece of shit

# stolen from ffmpeg configure like a pig
set -e

# prevent locale nonsense from breaking basic text processing
LC_ALL=C
export LC_ALL

init_file_name=init

init_ulinux_src_files='
ulinux/utils/ascii/string/vsprintf.c
ulinux/utils/mem.c
ulinux/utils/ascii/string/conv/decimal/decimal.c
'

init_src_files="
uevents.c
modules.c
uevent.c
init.c
ramfs.c
$init_ulinux_src_files
"

sep_start()
{
printf '###############################################################################\n'
}

sep_end()
{
printf '###############################################################################\n\n'
}

subsep_start()
{
printf '*******************************************************************************\n'
}

subsep_end()
{
printf '*******************************************************************************\n'
}

################################################################################

is_in()
{
value=$1
shift
for var in $*; do
	[ $var = $value ] && return 0
done
return 1
}

die_unknown(){
echo "Unknown option \"$1\"."
echo "See $0 --help for available options."
exit 1
}

set_default(){
for opt; do
	eval : \${$opt:=\$${opt}_default}
done
}

CMDLINE_SET='
linux_build_dir
kernel_modules_base_dir
init_cpp
init_cc
init_ccld
init_ulinux_arch
uevents_timeout
gen_init_cpio
kernel_release
extra_modules
pkg_config
elf_interpreter
'
# command line set defaults
# if the root is not around in less than 4s, something is really wrong
uevents_timeout_default=4000
gen_init_cpio_default='$linux_build_dir/usr/gen_init_cpio'
linux_build_dir_default=/usr/src/linux
#-------------------------------------------------------------------------------
# this defaults are for gcc, tested with version 4.7.3. You will need to
# override those for you compiler (tinycc/open64/pcc...). additionnally, source
# support for different toolchains is not done
# since we use standard C runtime libs, be nice with the C runtime
init_cpp_default='gcc -E -Wall -Wextra'
init_cc_default='gcc -Wall -Wextra -Wno-implicit-fallthrough -std=gnu99 -O2 -c'
init_ccld_default='gcc -Wl,-s -static'
#-------------------------------------------------------------------------------
kernel_modules_base_dir_default=/
kernel_release_default=$(uname -r)
init_ulinux_arch_default=$(uname -m | sed -e s/i.86/i386/ -e s/parisc64/parisc/ -e s/sun4u/sparc64/ -e s/arm.*/arm/ -e s/sa110/arm/ -e s/sh.*/sh/)
extra_modules_default=
pkg_config_default=pkg-config
elf_interpreter_default=

set_default $CMDLINE_SET

show_help()
{
cat <<EOF
Usage: make [options] [operations]

default is to build the the initramfs xz compressed cpio archive:

Options: [defaults in brackets after descriptions]

Help options:
  --help                               print this message

Standard options:
  --lib-path-list=LIB_PATH_LIST        colon separated paths to look for target libraries
  --uevents-timeout=UEVENTS_TIMEOUT    uevents timeout in ms looking up for root block device to go online [$uevents_timeout]
  --quiet                              init will be silenced (output code compiled out)
  --linux-build-dir=DIR                where to find the target linux build tree [$linux_build_dir_default]
  --kernel-release=RELEASE             the linux releases version [$kernel_release]
  --kernel-modules-base-dir=DIR        the base dir for linux modules and support files [$kernel_modules_base_dir]
  --extra-modules=EXTRA_MODULES        coma separated list of extra module to probe

Advanced options:
  --gen-init-cpio=GEN_INIT_CPIO_PATH   use this linux host tool to build the linux cpio initramfs [$gen_init_cpio_default]
  --pkg-config=PKG_CONFIG              use PKG_CONFIG pkg-config command for target libraries [$pkg_config_default]
  --init-cpp=CPP                       use CPP compiler command line CPP for target init process [$init_cpp_default]
  --init-cc=CC                         use C compiler command line CC for target init process objects [$init_cc_default]
  --init-ccld=CCLD                     use compiler driver linker command line CCLD for target init process [$init_ccld_default]
  --init-ulinux-arch=ARCH              use ulinux ARCH for target init process [$init_ulinux_arch]
EOF
exit 0
}

################################################################################

for opt do
	optval="${opt#*=}"
	case "$opt" in
		--help|-h) show_help
		;;
		--quiet) CPPFLAGS="$CPPFLAGS -DQUIET"
		;;
		*)
			optname=${opt%%=*}
			optname=${optname#--}
			optname=$(echo "$optname" | sed 's/-/_/g')
			if is_in $optname $CMDLINE_SET; then
				eval $optname='$optval'
			else
				die_unknown $opt
			fi
		;;
	esac
done

################################################################################

sep_start;echo 'looking for source path:'
if test -f make; then
	src_path=.
else
	src_path=$(cd $(dirname "$0"); pwd)
	echo "$src_path" | grep -q '[[:blank:]]' &&
		die "out of tree builds are impossible with whitespace in source path."
fi
echo "source path is $src_path";sep_end

################################################################################

sep_start;echo 'checking libkmod and libblkid pkgconfig support:'
if $pkg_config --exists libkmod blkid; then
	echo "found pkg-config files for libkmod and libblkid"
else
	echo "missing pkg-config file for libkmod or libblkid"
	exit 1
fi
sep_end

################################################################################

# define variable in source
CPPFLAGS="$CPPFLAGS -DUEVENTS_TIMEOUT=$uevents_timeout"
CPPFLAGS="$CPPFLAGS $($pkg_config --cflags-only-I libkmod blkid)"
CFLAGS="$CFLAGS $($pkg_config --cflags-only-other libkmod blkid)"
LIBS="$($pkg_config --libs --static libkmod blkid) $LIBS"

################################################################################

sep_start;echo 'configure ulinux src tree for target arch:'
rm -f $src_path/ulinux/arch
ln -s archs/$init_ulinux_arch $src_path/ulinux/arch
echo "init ulinux arch is $init_ulinux_arch"
sep_end

################################################################################

# generated some code/headers

sep_start
. $src_path/modules_revisions_all.sh
printf "$src_path/modules_revisions_all.sh was sourced:\n--------\n"
cat $src_path/modules_revisions_all.sh
echo '--------'
sep_end

sep_start
revision=$(echo "$kernel_release" | egrep -o '^[[:digit:]]+\.[[:digit:]]+')
if test -f $src_path/$revision; then
	. $src_path/$revision
	printf "linux revision is $revision, $src_path/$revision was sourced:\n--------\n"
	cat $src_path/$revision
	echo '--------'
else
	echo 'no revision specific modules to source'
fi
sep_end

# those modules are all loaded before anything else
sep_start;echo 'generate static module list:'
$src_path/script/static_modules_h.sh $extra_modules $DISK_MODULES \
                                                             >./static_modules.h
cat ./static_modules.h
sep_end

################################################################################

sep_start;echo 'C preprocess init src files:'
for init_src_file in $init_src_files
do
	init_pp_c_file=${init_src_file%.c}.pp.c
	echo "INIT_CPP $init_src_file->$init_pp_c_file"
	mkdir -p $(dirname $init_pp_c_file)
	$init_cpp	-o $init_pp_c_file		\
	    		$CPPFLAGS			\
	    		-I.				\
	    		-I$src_path			\
	    		$src_path/$init_src_file
	init_pp_c_files="$init_pp_c_file $init_pp_c_files"
done
sep_end

################################################################################

sep_start;echo 'compile init preprocessed src files:'
for init_pp_c_file in $init_pp_c_files
do
	init_obj_file=${init_pp_c_file%.pp.c}.o
	echo "INIT_CC $init_pp_c_file-->$init_obj_file"
	$init_cc $CFLAGS -o $init_obj_file $init_pp_c_file
	init_obj_files="$init_obj_file $init_obj_files"
done
sep_end

################################################################################

sep_start;echo 'link the init objects to produce the init binary:'
echo "INIT_CCLD $init_file_name"
$init_ccld -o $init_file_name $init_obj_files $LIBS
sep_end

################################################################################

sep_start;echo 'generate the cpio source file:'
sed -e "s:@INIT_PATH@:$(readlink -f  $init_file_name):" "$src_path/cpio.in" >cpio
echo "dir /lib/modules/$kernel_release 0755 0 0">>cpio

modules=$HW_MODULES,$DISK_MODULES,$FS_MODULES
if test -n "$extra_modules";then
	modules=$modules,$extra_modules
fi

subsep_start
#add proper entries in the cpio definition file related to linux modules
$src_path/script/cpio_modules_add.sh $kernel_modules_base_dir $kernel_release \
                                                                 $modules ./cpio
subsep_end

printf "cpio source file is:\n--------\n"
cat cpio
echo '--------'
sep_end

################################################################################

sep_start;echo 'generating and compressing the cpio archive'
e_gen_init_cpio=$(eval echo "$gen_init_cpio")
$e_gen_init_cpio cpio >${kernel_release}.cpio
xz --force --check=crc32 --extreme --stdout ${kernel_release}.cpio >${kernel_release}.cpio.xz
sep_end