Application preamble, get default settings
section .bss
; =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--= =--=
Termios resq 1 ; Pointer to default termios structure
_start enter 48, 0 ; Room for termios (keep stack qword aligned).
; Going to live on the edge a bit here and assume kernel has passed nulls to all
; volatile registers. At least that's the way it appears in GDB.
mov esi, TCGETS
mov rdx, rsp
mov al, SYS_IOCTL
syscall
inc rax ; Bump to see if -1 was returned
jnz .Ok
mov rsi, .NoTerm
call Console
jmp .Exit
.NoTerm db 10, 10, 'Opps, could not read termios structure', 10, 0
.Ok mov [Termios], rsp ; Save pointer might be needed in app body
Post-amble, reset to default just to be sure
.Exit mov rsi, SignOff
call Console
xor rax, rax ; Set return status
; Just to be sure, we'll return terminal to its default settings
mov rdi, rax ; STDIN does equal zero
mov ax, TCSETS ; which we know is 0x5402
mov rsi, rax
mov ax, SYS_IOCTL
mov rdx, rsp ; Stack should be pointing to termios struct
syscall
; Whatever the return status is here, we're going to pass it as apps return value
leave ; Cleanup procedure frame
; Whatever is in RAX is what application determines exit status should be.
mov rdi, rax ; Copy exit status
xor rax, rax
mov al, SYS_EXIT
syscall
NOTE: These listings depict a theory of operation, have been tested with GDB, but are only excerpts from original source.
