#!/bin/sh
# Start the X session once per boot, through poky's xserver-nodm chain:
# /etc/xserver-nodm/Xserver -> xinit -> /etc/X11/Xsession -> x-session-manager.
# Run from /etc/inittab under busybox init, or from /.bashrc when bash is PID 1.
# `brintos-x11-start --programs' prints what the pre-warm below runs, and exits.

# What the pre-warm runs. The window manager is the selected session's alone:
# matchbox-session stays installed beside the default icewm-session, and its
# window manager runs only when it is the one chosen.
programs() {
	(. /etc/default/xserver-nodm; echo "$XSERVER")
	echo /usr/bin/xkbcomp /usr/bin/dbus-launch /usr/bin/dbus-daemon \
		/usr/libexec/at-spi-bus-launcher /usr/bin/x-session-manager
	case "$(readlink -f /usr/bin/x-session-manager)" in
	*/icewm-session) echo /usr/bin/icewm /usr/bin/icewmbg ;;
	*/matchbox-session) echo /usr/bin/matchbox-window-manager ;;
	*) echo /usr/bin/x-window-manager ;;
	esac
	echo /usr/bin/x-terminal-emulator
}
[ "$1" = --programs ] && { programs; exit 0; }

# The opt-out xserver-nodm's own init script honours.
for x in $(cat /proc/cmdline); do
	[ "$x" = "x11=false" ] && exit 0
done

# Once per boot. /tmp is a tmpfs, so the stamp goes with a reboot; set -C makes
# the create atomic, so two callers cannot both start a server.
(set -C; : > /tmp/.brintos-x11-started) 2>/dev/null || exit 0

# Xorg will not start without its log file, and /var/log points into
# /var/volatile, which nothing on this image mounts yet (BRINTOS-2993 owns the
# volatiles). Once something does, this block does nothing.
if [ ! -d /var/log/ ]; then
	mount -t tmpfs -o mode=0755,nodev,nosuid tmpfs /var/volatile &&
		mkdir -p /var/volatile/log /var/volatile/tmp
fi
LOG=/var/log/xserver-nodm.log
[ -d /var/log/ ] || LOG=/tmp/xserver-nodm.log

# BRINTOS-WORKAROUND: brintos/linux#153 remove -- programs started together can still take each other's staged libraries (an interrupted staging read), and refuse to start.
# The session starts the server, xkbcomp, dbus, the window manager and a
# terminal within a second or two, all of them staging for the first time this
# boot. A library is staged once per boot, so starting each program once, one
# after another, leaves nothing for the session to race on. Scripts are
# skipped: they stage only the shell, and running one would start its session.
for p in $(programs); do
	[ -x "$p" ] || continue
	# dd, not head -c: an image with BusyBox's head alone has no -c.
	[ "$(dd if="$p" bs=2 count=1 2>/dev/null)" = "#!" ] && continue
	case "$(readlink -f "$p")" in
	*/Xorg|*/xkbcomp|*/xterm) v=-version ;;
	*/at-spi-bus-launcher) v=--help ;;
	*) v=--version ;;
	esac
	env -u DISPLAY "$p" $v </dev/null >/dev/null 2>&1
done

/etc/xserver-nodm/Xserver >"$LOG" 2>&1