Re: [Tutor] ctypes wintypes

On Fri, Oct 6, 2017 at 10:06 PM, Michael C
<[email protected]> wrote:
> like this?
>
> buffer = ctypes.byref(ctypes.create_string_buffer(4))

No, the buffer is the array created by create_string_buffer, which you
pass byref(). In the following example I create a `test` buffer that
contains "spam", and I use the pseudo-handle from GetCurrentProcess
with ReadProcessMemory to read this buffer into a target `buffer`.
It's silly to do this in the current process, but it's just an
example.

import ctypes
from ctypes.wintypes import HANDLE, LPVOID

kernel32 = ctypes.WinDLL('kernel32', use_last_error=True)

SIZE_T = ctypes.c_size_t
LPSIZE_T = ctypes.POINTER(SIZE_T)

kernel32.GetCurrentProcess.restype = HANDLE
kernel32.ReadProcessMemory.argtypes = (HANDLE, LPVOID,
    LPVOID, SIZE_T, LPSIZE_T)

hProcess = kernel32.GetCurrentProcess()
test = ctypes.create_string_buffer(b'spam')
address = ctypes.addressof(test)
buffer = ctypes.create_string_buffer(4)
nread = SIZE_T()

success = kernel32.ReadProcessMemory(hProcess, address,
    ctypes.byref(buffer), ctypes.sizeof(buffer),
    ctypes.byref(nread))

if not success:
    raise ctypes.WinError(ctypes.get_last_error())

print(buffer[:])

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