format ELF64 executable 3

include "utils.inc"

segment readable executable
entry start

macro print msg, msglen {
  mov rax, SYS_WRITE
  mov rdi, 1                 ; STDOUT
  lea rsi, [msg]
  mov rdx, msglen
  syscall
}

start:
    push "."                    ; pushing "." to stack (rsp)
    mov rdi, rsp                ; moving "." to rdi
    xor rsi, rsi                ; cleans rsi so SYS_OPEN doesnt try to use it as argument
    mov rdx, O_RDONLY           ; opening for read only
    mov rax, SYS_OPEN
    syscall                     ; rax contains the fd

    test rax, rax               ; check if fd != 0
    jz stop                     ; if fd = 0, open failed, we should exit

    mov rdi, rax                ; move fd to rdi
    lea rsi, [dirent]           ; struct dirent64
    mov rdx, 1024               ; buf size
    mov rax, SYS_GETDENTS64
    syscall                     ; dirent contains the directory entries

    test rax, rax               ; check directory list was successful
    js stop                     ; if negative code is returned, we failed and should exit

    mov rax, SYS_CLOSE          ; close source fd in rdi
    syscall
    
    xor rcx, rcx                ; will be the position in the directory entries

    print texto, 10            

stop:
    xor rdi, rdi        ; exit code 0
    mov rax, SYS_EXIT   ; sys_exit
    syscall

segment readable writable
dirent  dirent64
texto db "test", 0xA, 0
    

SYS_EXIT        = 60
SYS_OPEN        = 2
SYS_CLOSE       = 3
SYS_WRITE       = 1
SYS_READ        = 0
SYS_EXECVE      = 59
SYS_MMAP        = 9
SYS_GETDENTS64  = 217

O_RDONLY        = 0
O_DIRECTORY     = 0200000

DT_REG          = 8

struc dirent64 {
        .d_ino      dq ?    ; 64-bit inode number
        .d_off      dq ?    ; 64-bit offset to next struct
        .d_reclen   dw ?    ; size of this dirent
        .d_type     db ?    ; file type
        label .d_name byte
}
    

segment readable writable
texto db "test", 0xA, 0
dirent  dirent64
    

DIRENT_BUFSIZE = 1024    

    mov rdi, rax
    lea rsi, [dirent]
    mov rdx, DIRENT_BUFSIZE
    mov rax, SYS_GETDENTS64
    syscall    

segment readable writable
dirent  dirent64
        rb DIRENT_BUFSIZE - ($-dirent)