OpenFile在x86 NASM組件中不起作用

Question

我一直在使用以下代碼編寫程序，以打開其自身的文件句柄並讀取其內容，但是我遇到了問題...這是代碼...

extern GetStdHandle
extern GetModuleFileNameA
extern OpenFile
extern WriteFile
extern ExitProcess

import GetStdHandle kernel32.dll
import GetModuleFileNameA kernel32.dll
import OpenFile kernel32.dll
import WriteFile kernel32.dll
import ExitProcess kernel32.dll

global ..start

segment .code USE32

;Get standard output handle for writing to the console
push dword -11
call [GetStdHandle]
mov dword [hStdOut], eax

push dword filepath ;Buffer to store filepath
push dword 0 ;Setting this to NULL retrieves file name of 
             ;the program's exe on disk
call [GetModuleFileNameA] ;ANSI format of return string (the way that
                          ;OpenFile likes it)

;Here we are checking to see if the filename was returned
;On the console it looks blank but if you dump the output of the
;program to a file using the command program.exe > program.dump the
;path shows up in a hex editor. So the path is fine...
push dword 0
push dword bytesRead
push dword 128 ;Maximum path size for OpenFile
push dword filepath
push dword [hStdOut]
call [WriteFile]

push dword 0
push dword ofstruct
push dword filepath
call [OpenFile]
mov dword [hSelfFile], eax

push dword 0
push dword bytesRead
push dword 32 ;Arbitrary number to show the beginning of
              ;hSelfFile to see if the handle is pointing to
              ;the file. It should show the magic number MZ
              ;at the beginning if we're doing this right
push dword hSelfFile
push dword [hStdOut]
call [WriteFile] 

;Here is where we should see the elusive MZ magic number in the
;output

;Yes I will use CloseHandle (even though the program automatically
;closes all open handles before exiting), but for now I need to see
;if the OpenFile actually works or not before I do such things

push 0
call [ExitProcess]

segment .data

segment .bss
hStdOut resd 1
hSelfFile resd 1
bytesRead resd 1
ofstruct resb 136
filepath resb 128

樣品輸出...

---

C:\DOCUME~1\Admin\Desktop\asm>test0.exe
C:\DOCUME~1\Admin\Desktop\asm\test0.exe
                                            Φ      ê☺  σF±ÿC:\DOCUME~1\Admi
C:\DOCUME~1\Admin\Desktop\asm>

---

OpenFile我在做什么錯？

Answer 1

在WriteFile輸出文件內容之前，需要使用ReadFile將文件讀入緩沖區，僅通過將文件句柄從OpenFile傳遞到WriteFile不能讀取該文件。

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