使用 python 分配内存以传递给 dll
Allocation of Memory with python to pass to dll
我得到一个 dll，它需要一个指向 C 类型字节数组的内存指针。 dll 将读取和修改数组，并将一些额外的数据放在数组的末尾。
如何在python中分配1MB内存作为C类型字节数组并获取指针？
如何将 python 中的 C 类型字节数组写入此指针？
您可能想知道为什么我要这样做，但不幸的是这是此 dll 的唯一接口:/ 我必须在 python.
中这样做
这是我当前的设置：
import ctypes
# Allocate Memory:
BUFFER_LENGTH = 20
# parse to pointer:
bytes_buffer = bytes([0x13, 0x02, 0x03, 0x04, 0x08, 0xA5]) # dummy data
size_in = len(bytes_buffer)
print(bytes_buffer)
# write binary data to memory in CTypes Byte Array
buffer_in = ctypes.cast(bytes_buffer, ctypes.POINTER(ctypes.c_char*BUFFER_LENGTH) )
adr = ctypes.pointer(buffer_in)
address = id(adr)
# get pointer as int32
pointer_data_hi = ctypes.c_uint32(address)
pointer_data_lo = ctypes.c_uint32(address >> 32)
print("in: hi: " + str(pointer_data_hi.value) + ", lo: " + str(pointer_data_lo.value) + ", size: " + str(size_in))
# Load dll
array_modifier = ctypes.windll.LoadLibrary("PythonArrayToDll/modify_array_example/x64/Debug/modify_array_example.dll")
# set pointer of array to dll memory:
array_modifier.setAddrLo(pointer_data_lo)
array_modifier.setAddrHi(pointer_data_hi)
# tell the dll to compute something from the data array:
array_modifier.modifyArray() # this is where it crashes with exception: access violation reading 0xFFFFFFFFFFFFFFFF
# display the results:
for i in range(BUFFER_LENGTH):
print(buffer_in[i].value)
dll 代码（示例）：
#include <WinDef.h>
#include "pch.h"
#include "pointer_fnc.h"
#define DLL_EXPORT __declspec(dllexport)
int addrHi;
int addrLo;
extern "C"
{
DLL_EXPORT void setAddrLo(int lo)
{
addrLo = lo;
}
DLL_EXPORT void setAddrHi(int hi)
{
addrHi = hi;
}
DLL_EXPORT void modifyArray()
{
BYTE* my_array = (BYTE*)decode_integer_to_pointer(addrHi, addrLo);
my_array[0] = my_array[0] * 2;
my_array[1] = 2;
my_array[10] = my_array[0];
}
}
pointer_fnc.cpp 提供：
void* decode_integer_to_pointer(int hi, int lo)
{
#if PTRDIFF_MAX == INT64_MAX
union addrconv {
struct {
int lo;
int hi;
} base;
unsigned long long address;
} myaddr;
myaddr.base.lo = lo;
myaddr.base.hi = hi;
return reinterpret_cast<void*>(myaddr.address);
#elif PTRDIFF_MAX == INT32_MAX
return reinterpret_cast<void*>(lo);
#else
#error "Cannot determine 32bit or 64bit environment!"
#endif
}
dll被编译为64位，使用了64位python。
希望你能帮助我:)
清单[Python.Docs]: ctypes - A foreign function library for Python.
问题：
我粗略地浏览了 Functional Mock-up Interface ，但我没有看到任何对 API 的引用。无论如何，这个 hi, lo 方法很差（看起来它来自 16bit （段，偏移量）时代）。指针存在了几十年，而这正是它们的目的：处理内存地址
- 没有大小限制（从（起始）地址“可以走多远”），这意味着 API 消费者最终可能会访问内存他们不拥有（Undefined Behavior - 很可能崩溃）
以上让我觉得对 API
存在（很大）误解
不要混用Python和CTypes对象地址，它们是不一样的！ [Python.Docs]: Built-in Functions - id(object) returns Python 包装器对象 (PyObject) 地址，而不是实际的指针（你关心)
一个很常见的（缺少函数argtypes，restype）：，但它是不影响当前场景
既然你在Win，看看[MS.Docs]: ULARGE_INTEGER union (winnt.h)，不用重新发明轮子。无论如何，我删除了它以尽可能独立于平台
在 unsigned long long 中组合 2 ints 可能会对负值（符号hi
的位集）
更多次要的（不值得单独提及）
我准备了一个小例子
dll00.c:
#include <stdint.h>
#include <stdio.h>
#if defined(_WIN32)
# define DLL00_EXPORT_API __declspec(dllexport)
#else
# define DLL00_EXPORT_API
#endif
#define BYTE unsigned char
static uint32_t addrLo = 0;
static uint32_t addrHi = 0;
#if defined(__cplusplus)
extern "C" {
#endif
DLL00_EXPORT_API void setAddrLo(int lo);
DLL00_EXPORT_API void setAddrHi(int hi);
DLL00_EXPORT_API void modifyArray();
#if defined(__cplusplus)
}
#endif
void setAddrLo(int lo) {
addrLo = (uint32_t)lo;
}
void setAddrHi(int hi) {
addrHi = (uint32_t)hi;
}
static BYTE* toPtr(uint32_t hi, uint32_t lo) {
#if SIZE_MAX == 0xffffffffffffffffull
uint64_t quad = ((uint64_t)hi << 32) + lo;
printf("C - Addr: 0x%016llX, Hi: 0x%08X, Lo: 0x%08X\n", quad, hi, lo);
return (BYTE*)quad;
#elif SIZE_MAX == 0xfffffffful
printf("C - Addr: 0x%016llX, Hi: 0x%08X, Lo: 0x%08X\n", lo, hi, lo);
return (BYRE*)lo;
#else
# error "Neither 64bit nor 32bit architecture"
#endif
}
void modifyArray() { // A 'size' argument would be make sense to specify maximum array index.
BYTE *addr = toPtr(addrHi, addrLo);
if (addr == NULL) {
printf("C - NULL pointer!\n");
return;
}
addr[0] *= 2;
addr[1] = 2;
addr[10] = addr[0];
}
code00.py:
#!/usr/bin/env python
import sys
import ctypes as ct
DLL_NAME = "./dll00.{:s}".format("dll" if sys.platform[:3].lower() == "win" else "so")
BUF_LEN = 20
def main(*argv):
dll = ct.CDLL(DLL_NAME)
set_addr_lo = dll.setAddrLo
set_addr_lo.argtypes = (ct.c_int,)
set_addr_lo.restype = None
set_addr_hi = dll.setAddrHi
set_addr_hi.argtypes = (ct.c_int,)
set_addr_hi.restype = None
modify_array = dll.modifyArray
modify_array.argtypes = ()
modify_array.restype = None
b = b"\x20\x03\x20"
Array = ct.c_char * BUF_LEN
buf = Array(*b)
print("PY - Array: {:}".format(list(ord(i) for i in buf)))
addr = ct.addressof(buf) # The reverse of what's done in the .dll (toPtr) - doesn't make much sense
if sys.maxsize > 0x100000000:
lo = addr & 0xffffffff
hi = (addr >> 32) & 0xffffffff
else:
hi = 0
lo = addr
print("PY - Addr: 0x{:016X}, Hi: 0x{:08X}, Lo: 0x{:08X}".format(addr, hi, lo))
set_addr_lo(lo)
set_addr_hi(hi)
modify_array()
print("PY - Array: {:}".format(list(ord(i) for i in buf)))
if __name__ == "__main__":
print("Python {:s} {:03d}bit on {:s}\n".format(" ".join(elem.strip() for elem in sys.version.split("\n")),
64 if sys.maxsize > 0x100000000 else 32, sys.platform))
rc = main(*sys.argv[1:])
print("\nDone.")
sys.exit(rc)
输出:
[cfati@CFATI-5510-0:e:\Work\Dev\Whosebug\q068304564]> sopr.bat
### Set shorter prompt to better fit when pasted in Whosebug (or other) pages ###
[prompt]> "c:\Install\pc032\Microsoft\VisualStudioCommunity19\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul
[prompt]> dir /b
code00.py
dll00.c
[prompt]>
[prompt]> cl /nologo /MD /DDLL dll00.c /link /NOLOGO /DLL /OUT:dll00.dll
dll00.c
Creating library dll00.lib and object dll00.exp
[prompt]> dir /b
code00.py
dll00.c
dll00.dll
dll00.exp
dll00.lib
dll00.obj
[prompt]>
[prompt]> "e:\Work\Dev\VEnvs\py_pc064_03.08.07_test0\Scripts\python.exe" code00.py
Python 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)] 064bit on win32
PY - Array: [32, 3, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
PY - Addr: 0x00000203275B23B0, Hi: 0x00000203, Lo: 0x275B23B0
C - Addr: 0x00000203275B23B0, Hi: 0x00000203, Lo: 0x275B23B0
PY - Array: [64, 2, 32, 0, 0, 0, 0, 0, 0, 0, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0]
Done.
我得到一个 dll，它需要一个指向 C 类型字节数组的内存指针。 dll 将读取和修改数组，并将一些额外的数据放在数组的末尾。
如何在python中分配1MB内存作为C类型字节数组并获取指针？
如何将 python 中的 C 类型字节数组写入此指针？
您可能想知道为什么我要这样做，但不幸的是这是此 dll 的唯一接口:/ 我必须在 python.
中这样做这是我当前的设置：
import ctypes
# Allocate Memory:
BUFFER_LENGTH = 20
# parse to pointer:
bytes_buffer = bytes([0x13, 0x02, 0x03, 0x04, 0x08, 0xA5]) # dummy data
size_in = len(bytes_buffer)
print(bytes_buffer)
# write binary data to memory in CTypes Byte Array
buffer_in = ctypes.cast(bytes_buffer, ctypes.POINTER(ctypes.c_char*BUFFER_LENGTH) )
adr = ctypes.pointer(buffer_in)
address = id(adr)
# get pointer as int32
pointer_data_hi = ctypes.c_uint32(address)
pointer_data_lo = ctypes.c_uint32(address >> 32)
print("in: hi: " + str(pointer_data_hi.value) + ", lo: " + str(pointer_data_lo.value) + ", size: " + str(size_in))
# Load dll
array_modifier = ctypes.windll.LoadLibrary("PythonArrayToDll/modify_array_example/x64/Debug/modify_array_example.dll")
# set pointer of array to dll memory:
array_modifier.setAddrLo(pointer_data_lo)
array_modifier.setAddrHi(pointer_data_hi)
# tell the dll to compute something from the data array:
array_modifier.modifyArray() # this is where it crashes with exception: access violation reading 0xFFFFFFFFFFFFFFFF
# display the results:
for i in range(BUFFER_LENGTH):
print(buffer_in[i].value)
dll 代码（示例）：
#include <WinDef.h>
#include "pch.h"
#include "pointer_fnc.h"
#define DLL_EXPORT __declspec(dllexport)
int addrHi;
int addrLo;
extern "C"
{
DLL_EXPORT void setAddrLo(int lo)
{
addrLo = lo;
}
DLL_EXPORT void setAddrHi(int hi)
{
addrHi = hi;
}
DLL_EXPORT void modifyArray()
{
BYTE* my_array = (BYTE*)decode_integer_to_pointer(addrHi, addrLo);
my_array[0] = my_array[0] * 2;
my_array[1] = 2;
my_array[10] = my_array[0];
}
}
pointer_fnc.cpp 提供：
void* decode_integer_to_pointer(int hi, int lo)
{
#if PTRDIFF_MAX == INT64_MAX
union addrconv {
struct {
int lo;
int hi;
} base;
unsigned long long address;
} myaddr;
myaddr.base.lo = lo;
myaddr.base.hi = hi;
return reinterpret_cast<void*>(myaddr.address);
#elif PTRDIFF_MAX == INT32_MAX
return reinterpret_cast<void*>(lo);
#else
#error "Cannot determine 32bit or 64bit environment!"
#endif
}
dll被编译为64位，使用了64位python。
希望你能帮助我:)
清单[Python.Docs]: ctypes - A foreign function library for Python.
问题：
我粗略地浏览了 Functional Mock-up Interface ，但我没有看到任何对 API 的引用。无论如何，这个 hi, lo 方法很差（看起来它来自 16bit （段，偏移量）时代）。指针存在了几十年，而这正是它们的目的：处理内存地址
- 没有大小限制（从（起始）地址“可以走多远”），这意味着 API 消费者最终可能会访问内存他们不拥有（Undefined Behavior - 很可能崩溃）
以上让我觉得对 API
存在（很大）误解不要混用Python和CTypes对象地址，它们是不一样的！ [Python.Docs]: Built-in Functions - id(object) returns Python 包装器对象 (PyObject) 地址，而不是实际的指针（你关心)
一个很常见的（缺少函数argtypes，restype）：
既然你在Win，看看[MS.Docs]: ULARGE_INTEGER union (winnt.h)，不用重新发明轮子。无论如何，我删除了它以尽可能独立于平台
在 unsigned long long 中组合 2 ints 可能会对负值（符号hi
的位集）更多次要的（不值得单独提及）
我准备了一个小例子
dll00.c:
#include <stdint.h>
#include <stdio.h>
#if defined(_WIN32)
# define DLL00_EXPORT_API __declspec(dllexport)
#else
# define DLL00_EXPORT_API
#endif
#define BYTE unsigned char
static uint32_t addrLo = 0;
static uint32_t addrHi = 0;
#if defined(__cplusplus)
extern "C" {
#endif
DLL00_EXPORT_API void setAddrLo(int lo);
DLL00_EXPORT_API void setAddrHi(int hi);
DLL00_EXPORT_API void modifyArray();
#if defined(__cplusplus)
}
#endif
void setAddrLo(int lo) {
addrLo = (uint32_t)lo;
}
void setAddrHi(int hi) {
addrHi = (uint32_t)hi;
}
static BYTE* toPtr(uint32_t hi, uint32_t lo) {
#if SIZE_MAX == 0xffffffffffffffffull
uint64_t quad = ((uint64_t)hi << 32) + lo;
printf("C - Addr: 0x%016llX, Hi: 0x%08X, Lo: 0x%08X\n", quad, hi, lo);
return (BYTE*)quad;
#elif SIZE_MAX == 0xfffffffful
printf("C - Addr: 0x%016llX, Hi: 0x%08X, Lo: 0x%08X\n", lo, hi, lo);
return (BYRE*)lo;
#else
# error "Neither 64bit nor 32bit architecture"
#endif
}
void modifyArray() { // A 'size' argument would be make sense to specify maximum array index.
BYTE *addr = toPtr(addrHi, addrLo);
if (addr == NULL) {
printf("C - NULL pointer!\n");
return;
}
addr[0] *= 2;
addr[1] = 2;
addr[10] = addr[0];
}
code00.py:
#!/usr/bin/env python
import sys
import ctypes as ct
DLL_NAME = "./dll00.{:s}".format("dll" if sys.platform[:3].lower() == "win" else "so")
BUF_LEN = 20
def main(*argv):
dll = ct.CDLL(DLL_NAME)
set_addr_lo = dll.setAddrLo
set_addr_lo.argtypes = (ct.c_int,)
set_addr_lo.restype = None
set_addr_hi = dll.setAddrHi
set_addr_hi.argtypes = (ct.c_int,)
set_addr_hi.restype = None
modify_array = dll.modifyArray
modify_array.argtypes = ()
modify_array.restype = None
b = b"\x20\x03\x20"
Array = ct.c_char * BUF_LEN
buf = Array(*b)
print("PY - Array: {:}".format(list(ord(i) for i in buf)))
addr = ct.addressof(buf) # The reverse of what's done in the .dll (toPtr) - doesn't make much sense
if sys.maxsize > 0x100000000:
lo = addr & 0xffffffff
hi = (addr >> 32) & 0xffffffff
else:
hi = 0
lo = addr
print("PY - Addr: 0x{:016X}, Hi: 0x{:08X}, Lo: 0x{:08X}".format(addr, hi, lo))
set_addr_lo(lo)
set_addr_hi(hi)
modify_array()
print("PY - Array: {:}".format(list(ord(i) for i in buf)))
if __name__ == "__main__":
print("Python {:s} {:03d}bit on {:s}\n".format(" ".join(elem.strip() for elem in sys.version.split("\n")),
64 if sys.maxsize > 0x100000000 else 32, sys.platform))
rc = main(*sys.argv[1:])
print("\nDone.")
sys.exit(rc)
输出:
[cfati@CFATI-5510-0:e:\Work\Dev\Whosebug\q068304564]> sopr.bat ### Set shorter prompt to better fit when pasted in Whosebug (or other) pages ### [prompt]> "c:\Install\pc032\Microsoft\VisualStudioCommunity19\VC\Auxiliary\Build\vcvarsall.bat" x64 >nul [prompt]> dir /b code00.py dll00.c [prompt]> [prompt]> cl /nologo /MD /DDLL dll00.c /link /NOLOGO /DLL /OUT:dll00.dll dll00.c Creating library dll00.lib and object dll00.exp [prompt]> dir /b code00.py dll00.c dll00.dll dll00.exp dll00.lib dll00.obj [prompt]> [prompt]> "e:\Work\Dev\VEnvs\py_pc064_03.08.07_test0\Scripts\python.exe" code00.py Python 3.8.7 (tags/v3.8.7:6503f05, Dec 21 2020, 17:59:51) [MSC v.1928 64 bit (AMD64)] 064bit on win32 PY - Array: [32, 3, 32, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] PY - Addr: 0x00000203275B23B0, Hi: 0x00000203, Lo: 0x275B23B0 C - Addr: 0x00000203275B23B0, Hi: 0x00000203, Lo: 0x275B23B0 PY - Array: [64, 2, 32, 0, 0, 0, 0, 0, 0, 0, 64, 0, 0, 0, 0, 0, 0, 0, 0, 0] Done.