#!/bin/sh
# Copyright (C) 2011 O.S. Systems Software LTDA.
# Licensed on MIT
#
# Provides the API to be used by the initramfs modules
#
# Modules need to provide the following functions:
#
# <module>_enabled : check if the module ought to run (return 1 to skip)
# <module>_run     : do what is need
#
# Boot parameters are available on environment in the as:
#
# 'foo=value' as 'bootparam_foo=value'
# 'foo' as 'bootparam_foo=true'

# Register a function to be called before running a module
# The hook is called as:
#   <function> pre <module>
add_module_pre_hook() {
	MODULE_PRE_HOOKS="$MODULE_PRE_HOOKS $1"
}

# Register a function to be called after running a module
# The hook is called as:
#   <function> post <module>
add_module_post_hook() {
	MODULE_POST_HOOKS="$MODULE_POST_HOOKS $1"
}

# Load kernel module
load_kernel_module() {
	if modprobe $1 >/dev/null 2>&1; then
		info "Loaded module $1"
	else
		debug "Failed to load module $1"
	fi
}

# Prints information
msg() {
	echo "$@" >/dev/console
}

# Prints information if verbose bootparam is used
info() {
	[ -n "$bootparam_verbose" ] && echo "$@" >/dev/console
}

# Prints information if debug bootparam is used
debug() {
	[ -n "$bootparam_debug" ] && echo "DEBUG: $@" >/dev/console
}

# Prints a message and start a endless loop
fatal() {
    echo $1 >/dev/console
    echo >/dev/console

	while [ "true" ]; do
		sleep 3600
	done
}

# Variables shared amoung modules
ROOTFS_DIR="/rootfs" # where to do the switch root
MODULE_PRE_HOOKS=""  # functions to call before running each module
MODULE_POST_HOOKS="" # functions to call after running each module
MODULES_DIR=/init.d  # place to look for modules

# make mount stop complaining about missing /etc/fstab
touch /etc/fstab

# initialize /proc, /sys and /var/lock
mkdir -p /proc /sys /var/lock
mount -t proc proc /proc
mount -t sysfs sysfs /sys

# populate bootparam environment
for p in `cat /proc/cmdline`; do
	opt=`echo $p | cut -d'=' -f1`
	opt=`echo $opt | sed -e 's/-/_/'`
	if [ "`echo $p | cut -d'=' -f1`" = "$p" ]; then
		eval "bootparam_${opt}=true"
	else
		value="`echo $p | cut -d'=' -f2-`"
		eval "bootparam_${opt}=\"${value}\""
	fi
done

# use /dev with devtmpfs
if grep -q devtmpfs /proc/filesystems; then
	mkdir -p /dev
	mount -t devtmpfs devtmpfs /dev
else
	if [ ! -d /dev ]; then
		fatal "ERROR: /dev doesn't exist and kernel doesn't has devtmpfs enabled."
	fi
fi

mkdir $ROOTFS_DIR

# Load and run modules
for m in $MODULES_DIR/*; do
	# Skip backup files
	if [ "`echo $m | sed -e 's/\~$//'`" = "$m" ]; then
		continue
	fi

	module=`basename $m | cut -d'-' -f 2`
	debug "Loading module $module"

	# pre hooks
	for h in $MODULE_PRE_HOOKS; do
		debug "Calling module hook (pre): $h"
		eval "$h pre $module"
		debug "Finished module hook (pre): $h"
	done

	# process module
	. $m

	if ! eval "${module}_enabled"; then
		debug "Skipping module $module"
		continue
	fi

	debug "Running ${module}_run"
	eval "${module}_run"

	# post hooks
	for h in $MODULE_POST_HOOKS; do
		debug "Calling module hook (post): $h"
		eval "$h post $module"
		debug "Finished module hook (post): $h"
	done
done

# Catch all
fatal "ERROR: Initramfs failed to initialize the system."
