Question

我正在尝试在我的mac操作系统上编写一个简单的内存读取器/写入器，但我遇到了问题。

写作方面工作正常，甚至vm_read返回KERN_SUCCESS。但是当我尝试打印我在vm_read中引用的缓冲区时，它给了我一个错误的值。

#include <iostream>
#include <mach/mach_init.h>
#include <mach/mach.h>

using namespace std;

int main() {
    int start = 1337;
    int value = 100;

    uintptr_t buf;
    uint32_t bytesRead;

    task_t task;

    task_for_pid(current_task(), getpid(), &task);

    cout << "Step 1 (before write, should = 1337): " << start << endl;

    int reason = 0;
    if ((reason = vm_write(task, (uintptr_t) &start, (uintptr_t) &value, sizeof(int))) != KERN_SUCCESS) {
        cout << "Failed to write: " << reason << endl;
    }

    if ((reason = vm_read(task, (uintptr_t) &start, sizeof(int), &buf, &bytesRead)) != KERN_SUCCESS) {
        cout << "Failed to read: " << reason << endl;
    }

    cout << "Step 2 (after write, should = 100): " << buf << endl;
    return 0;
}

以下代码输出：

/Users/Jonathan/Library/Caches/CLion12/cmake/generated/4f3c65b6/4f3c65b6/Debug/helloworld
Step 1 (before write, should = 1337): 1337
Step 2 (after write, should = 100): 4415766528

Process finished with exit code 0

步骤2应该打印100，因为我将值100写入start变量。（如果我cout << start << endl;它打印100）。

知道出了什么问题吗？谢谢！

Answer 1

尝试将步骤2替换为：

cout << "Step 2 (after write, should = 100): " << (*(int*)buf) << endl;

Buf是指向您读取的数据的指针，因此您必须取消引用它才能从中获取实际的整数。

C ++ Mac OS X 10.11.2 vm_read给出了错误的值

1 个答案: