section .data
yourinputis db "your input is =",0
len equ $ - yourinputis

section .bss
msginput    resb    10

section .text
global _start


_start:
    mov eax,3 ;read syscall
    mov ebx,2
    mov ecx,msginput
    mov edx,9 ; I don't know that is correct?
    int 80h

    mov eax,4 ;write syscall
    mov ebx,1
    mov ecx,yourinputis
    mov edx,len
    int 80h

    mov eax,4 ;write syscall
    mov ebx,1
    mov ecx,msginput
    mov edx,10
    int 80h


exit:
    mov eax,1 ;exit syscall
    xor ebx,ebx
    int 80h

This code working very well. But It is so terrible bug(for me:(). If I enter an input longer than 10 --->

$./mycode
012345678rm mycode
your input is 012345678$rm mycode
$

This is happening. And of course "mycode" is not exist right now.

What should I do?

EDIT:The entered input is correctly printed on the screen. But if you enter a long input, it moves after the 9th character to the shell and runs it.

In the example, the "rm mycode" after "012345678" is running in the shell.

CodePudding user response：

If you enter more than 9 characters, they're left in the terminal driver's input buffer. When the program exits, the shell reads from the terminal and tries to execute the rest of the line as a command.

To prevent this, your program should keep reading in a loop until it gets a newline.

CodePudding user response：

You can read the characters one by one until you reach 0x0a. Something like:

_read:
    mov esi, msginput

_loop:
    mov eax,3 ;read syscall
    mov ebx,2
    mov ecx, esi
    mov edx,1 ; I don't know that is correct?
    int 80h

    cmp byte[msginput], 0x0a
    je end

    inc esi
    jmp _loop

end:
   ret

You would have to increase the size of msginput tho.