;=================================================================================
; sys_sysctl demonstration. 
;
; Changes system's hostname.
;
; The LSCR Project. 
;=================================================================================

format ELF

include '../macros.inc'
include '../../include/symbols.inc'
include '../../include/structs.inc'

extrn error_chk

section '.text' executable 

public _start
_start:
        mov     [my__sysctl_args.name], name                            ; write the new value
        mov     [my__sysctl_args.nlen], 8

        mov     [my__sysctl_args.oldval], oldval
        mov     [my__sysctl_args.oldlenp], oldval_sz
        
        mov     [my__sysctl_args.newval], newhostname
        mov     [my__sysctl_args.newlen], 3
        
	mov	eax, SYS_SYSCTL
	mov 	ebx, my__sysctl_args
	int 	0x80
        ccall	error_chk, <"SYS_SYSCTL has failed: ">, exit

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, str_s
	mov	edx, str_s_sz
	int	0x80    

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, oldval
	mov	edx, [oldval_sz]
	int	0x80     

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, nl
	mov	edx, 1
	int	0x80   

        mov     [my__sysctl_args.name], name                            ; retreive the newly written value
        mov     [my__sysctl_args.nlen], 8

        mov     [my__sysctl_args.oldval], oldval
        mov     [oldval_sz], 128
        mov     [my__sysctl_args.oldlenp], oldval_sz
        
        mov     [my__sysctl_args.newval], 0
        
	mov	eax, SYS_SYSCTL
	mov 	ebx, my__sysctl_args
	int 	0x80
        ccall	error_chk, <"SYS_SYSCTL has failed: ">, exit

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, str1_s
	mov	edx, str1_s_sz
	int	0x80    

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, oldval
	mov	edx, [oldval_sz]
	int	0x80   

        mov	eax, SYS_WRITE
	mov	ebx, STDOUT
	mov	ecx, nl
	mov	edx, 1
	int	0x80   

exit:	mov     eax, SYS_EXIT
	xor     ebx, ebx
	int	0x80

section '.data' writeable

str_s           db "Old hostname: "
str_s_sz = $-str_s
str1_s          db "New hostname: "
str1_s_sz = $-str1_s

nl              db 0xa

newhostname     db "b0x"

name            dd CTL_KERN
                dd KERN_NODENAME

oldval_sz       dd 128

oldval          rb 128
my__sysctl_args   __sysctl_args