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This article provides information about how to list a directory’s content and get the names of its files with the help of the Win32 API. This code is therefore incompatible with Linux based operating systems (unless you’re using Wine).

The source code below gets all files located at C:\test\ and outputs their names via a MessageBoxA.

[code]format PE GUI 4.0
entry start

include ‘win32a.inc’

start:
push DST_PATH
call EnumFiles

DST_PATH db ‘C:\test\*.*’, 0 ; Directory to list files from. Change it according to your needs.

proc EnumFiles, szPath
locals
hFindFile dd ?
endl
sub esp, 0x140 ; Free some space on the stack for our WIN32_FIND_DATA struct
mov ebx, esp ; ebx now holds our struct
push ebx
push [szPath]
call [FindFirstFileA]
test eax, eax
jz .list_end
mov [hFindFile], eax
lea esi, [ebx+0x2C] ; = FileName
mov ecx, [ebx+0x20] ; = FileSize
.fileloop:
push ebx
push [hFindFile]
call [FindNextFileA]
test eax, eax
jz .list_end ; If there’re no more files, exit the loop
mov ecx, [ebx+0x20] ; = FileSize (in Bytes). Is 0 when it’s a directory
invoke MessageBoxA,HWND_DESKTOP,esi,txt_msg_caption,0 ; =>> Show a MessageBox containing the name of the current file/directory <==
jmp .fileloop
.list_end:
add esp, 0x140 ; Restore stack
invoke MessageBoxA,HWND_DESKTOP,txt_msg_text,txt_msg_caption,0
call [ExitProcess]

; Custom Data: Some Strings which will be shown in a MessageBoxA later:
section ‘.data’ data readable writeable
txt_msg_caption db ‘TEST’,0
txt_msg_text db ‘[ Listing the directory has been finished ]’,0

; Imported functions and corresponding names of DLL files:
section ‘.idata’ import data readable writeable
library kernel,’KERNEL32.DLL’,\
user,’USER32.DLL’

import kernel,\
ExitProcess,’ExitProcess’,\
FindFirstFileA,’FindFirstFileA’,\
FindNextFileA,’FindNextFileA’

import user,\
MessageBoxA,’MessageBoxA’

ret ; Not really needed
endp[/code]

C:\test\