/*
 * Must switch to fasm
 *
 * This assembly source code is intended to be preprocessed:
 *	- don't use # comments
 *      - do use your C compiler front-end with proper specific options or do
 *	  pipe cpp output to as (don't forget to link as an executable then)
 *
 * 	cpp user.S | as -o user.o; ld -o user user.o
 * 
 * dbus will want an entry in /etc/passwd for user
 */

.data
dbus:		.asciz "/nyan/dbus/current/bin/dbus-run-session"
shell:		.asciz "/bin/sh"
shell_arg0:	.asciz "-l"
shell_arg1:	.asciz "-c"
shell_arg2:	.asciz "exec /home/user/steam/steam"


home:		.asciz "HOME=/home/user"
path:		.asciz "PATH=/nyan/dbus/current/bin"
ldpath:		.asciz "LD_LIBRARY_PATH=/nyan/dbus/current/lib"

argv:		.quad dbus, shell, shell_arg0, shell_arg1, shell_arg2, 0
envp:		.quad home, path, ldpath, 0
/* alsa audio group is 116 */
groups:		.quad 116

.text
/* _start is the ELF symbol which defines the program entry point */
	.global _start
_start:
	mov $116, %eax		/* setgroups */
	mov $1, %rdi		/* 1 group */
	mov $groups, %rsi	/* audio */
	syscall
	mov $106, %eax		/* setgid */
	mov $1000, %rdi		/* GID=1000 */
	syscall
	mov $105, %eax		/* setuid */
	mov $1000, %rdi		/* UID=1000 */
	syscall
	mov $59, %eax		/* execve */
	mov $dbus, %rdi
	mov $argv, %rsi
	mov $envp, %rdx
/* never returning syscall */
	syscall