#!/bin/sh
# Early boot, once per boot: busybox init's one ::sysinit action. Mounts what
# the kernel has not, stacks a tmpfs on /tmp over the kernel's, then runs the
# memory-backed directories, /etc/default/volatiles, mdev, the network and the
# deferred maintainer scripts, in that order. Each step is recorded in
# /run/brintos-sysinit as "<step> <result>".
#
# Nothing here may call setsid or cttyhack, or start a daemon in the
# background: this runtime lacks the syscalls, and init waits for this script
# before it starts the console.

LOG=/run/brintos-sysinit
_log=

mounted() {
	awk -v m="$1" '$2 == m { f = 1 } END { exit !f }' /proc/mounts 2>/dev/null
}

# The log reaches /run once /run is a tmpfs; the earlier steps are kept until then.
note() {
	_log="$_log$1 $2
"
	mounted /run && printf '%s' "$_log" > "$LOG"
}

# Run a step if its program is installed, and record how it ended.
step() {
	_name=$1
	shift
	if [ -x "$1" ]; then
		"$@"
		note "$_name" "rc=$?"
	else
		note "$_name" absent
	fi
}

# /etc/default/volatiles, in populate-volatile.sh's format:
# <type> <owner> <group> <mode> <path> <source>, type d, f, l or b.
volatiles() {
	_rc=0
	for _f in /etc/default/volatiles/*; do
		[ -f "$_f" ] || continue
		sed 's/#.*//' "$_f" | {
			_bad=0
			while read -r _t _u _g _m _p _s; do
				[ -n "$_s" ] || continue
				[ -L "$_p" ] && [ ! -e "$_p" ] && _p=$(readlink -f "$_p")
				case $_t in
				d) [ -e "$_p" ] || { mkdir -p "$_p" && chown "$_u:$_g" "$_p" && chmod "$_m" "$_p"; } ;;
				f) [ -e "$_p" ] || {
					if [ "$_s" = none ]; then : > "$_p"; else cp "$_s" "$_p"; fi &&
						chown "$_u:$_g" "$_p" && chmod "$_m" "$_p"
				} ;;
				l) [ -d "$_p" ] && [ ! -L "$_p" ] || [ "$(readlink "$_p")" = "$_s" ] || ln -sfn "$_s" "$_p" ;;
				b) mounted "$_p" || mount --bind "$_s" "$_p" ;;
				*) false ;;
				esac || {
					echo "brintos-sysinit: $_f: $_t $_p failed" >&2
					_bad=1
				}
			done
			exit $_bad
		} || _rc=1
	done
	return $_rc
}

if [ -e /proc/mounts ]; then
	note proc kernel
else
	mount -t proc proc /proc
	note proc "rc=$?"
fi
if mounted /sys; then
	note sys kernel
else
	mount -t sysfs sysfs /sys
	note sys "rc=$?"
fi
mount -t tmpfs -o mode=1777,nosuid,nodev tmpfs /tmp
note tmp "rc=$?"
if mounted /run; then
	note run mounted
else
	mount -t tmpfs -o mode=0755,nodev,nosuid,strictatime tmpfs /run
	note run "rc=$?"
fi

step volatile /sbin/brintos-volatile
if [ -d /etc/default/volatiles ]; then
	volatiles
	note volatiles "rc=$?"
else
	note volatiles absent
fi
# A coldplug scan only: mdev's own init script starts it as a daemon through
# start-stop-daemon -b, which needs setsid.
step mdev /sbin/mdev -s
step network /etc/init.d/brintos-network start
step run-postinsts /usr/sbin/run-postinsts
exit 0