#
# Build script to autogenerate and compile a container image
#
# Copyright (C) 2009 B Labs
#
import os
import sys
import shutil
from os.path import join

linux_kernel_path = join("/opt/codezero/build/conts/linux/arch/arm/boot/compressed/vmlinux")
rootfs_path = join("rootfs/rootfs.elf")

container_assembler_body = \
'''
.align 4
.section .img.%d
.incbin "%s"
'''

container_lds_start = \
'''/*
 * Autogenerated linker script that embeds each container image.
 *
 * Copyright (C) 2009 B Labs
 */

SECTIONS
{'''

container_lds_body = \
'''
	.img.%d : { *(.img.%d) }'''

container_lds_end = \
'''
}
'''

# TODO: This might be done much more elegantly and flexibly.
#
# But it makes sense to put the image finding logic to a function
# rather than hard-code it in an array at the beginning.
def collect_images(target, source, env):
	cmd1 = "cp " + linux_kernel_path + " ./"
	cmd2 = "cp " + rootfs_path + " ./"
	os.system(cmd1)
	os.system(cmd2)
	os.system("echo " + cmd1)
	os.system("echo " + cmd2)

	images.append("vmlinux")
	images.append("rootfs.elf")
	for i in images:
		print i

def generate_container_assembler(source, target, env):
	f = open("container.S", "w+")
	file_body = ""
	img_i = 0
	for img in source:
		file_body += container_assembler_body % (img_i, img)
		img_i += 1

	f.write(file_body)
	f.close()

def generate_container_lds(source, target, env):
	f = open("container.lds", "w+")
	img_i = 0
	file_body = container_lds_start
	for img in source:
		file_body += container_lds_body % (img_i, img_i)
		img_i += 1
	file_body += container_lds_end
	f.write(file_body)
	f.close()

def build_rootfs(source, target, env):
	os.chdir("./rootfs")
	os.system("./build_rootfs.sh")
	os.chdir("..")

def build_linux(source, target, env):
	os.system("./build_linux.sh")

env = Environment(CC = 'arm-none-linux-gnueabi-gcc',
		  CCFLAGS = ['-g', '-nostdlib', '-ffreestanding', \
			     '-std=gnu99', '-Wall', '-Werror'],
		  LINKFLAGS = ['-nostdlib'],
		  PROGSUFFIX = '.elf',			# The suffix to use for final executable
		  ENV = {'PATH' : os.environ['PATH']},	# Inherit shell path
		  )
images = []
linux_kernel = env.Command(linux_kernel_path, "linux-2.6.28.10", build_linux)
rootfs = env.Command(rootfs_path, "rootfs/rootfs.img", build_rootfs)
env.Command(["vmlinux", "rootfs.elf"], [linux_kernel_path, rootfs_path], collect_images)
container_S = env.Command("container.S", ["vmlinux", "rootfs.elf"], generate_container_assembler)
container_lds = env.Command("container.lds", ["vmlinux", "rootfs.elf"], generate_container_lds)

env.Replace(LINKFLAGS = ['-nostdlib', '-Tcontainer.lds'])
env.Replace(PROGSUFFIX = '.elf')
objs = env.Object('container.S')
container = env.Program('container.elf', objs)
env.Depends(container, [linux_kernel, rootfs, container_S, container_lds])