win32 - 内存映射(CreateFileMapping)

目标：创建一个app，使用CreateToolhelp32Snapshot扫描所有的进程，并将进程的pid和exe名字映射到内存中，再在另一个app中使用OpenFileMapping打开该映射读取相关数据

Project 1:

#define _CRT_SECURE_NO_WARNINGS
#include <Windows.h>
#include <stdio.h>
#include <Tlhelp32.h>
#include <vector>

struct InfoProces {
    DWORD pid;
    DWORD ppid;
    char  exeName[256];
};

int main() {
    HANDLE hProcesses;
    PROCESSENTRY32 pe32;

    hProcesses = CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
    if (hProcesses == INVALID_HANDLE_VALUE)
    {
        printf("CreateToolhelp32Snapshot failed. err = %d", GetLastError());
        return -1;
    }

    pe32.dwSize = sizeof(PROCESSENTRY32);

    if (!Process32First(hProcesses, &pe32)) {
        printf("Process32First failed. err = %d", GetLastError());
        CloseHandle(hProcesses);
        return -1;
    }

    HANDLE hdata = CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, 1024 * 1024, "data");
    if (hdata == NULL) {
        printf("Can't create a file mapping. err = %d", GetLastError());
        return -1;
    }

    unsigned char* pdata = (unsigned char*)MapViewOfFile(hdata, FILE_MAP_WRITE, 0, 0, 0);
    if (pdata == NULL) {
        printf("cant get pointer to mapping file. err = %d", GetLastError());
        return -1;
    }

    unsigned char* begin = pdata;
    DWORD count = 0;
    pdata += sizeof(DWORD);

    do {
        InfoProces pi;
        pi.pid = pe32.th32ProcessID;
        pi.ppid = pe32.th32ParentProcessID;
        strcpy(pi.exeName, pe32.szExeFile);
        memcpy(pdata, &pi, sizeof(InfoProces));
        pdata += sizeof(InfoProces);
        count++;

    } while (Process32Next(hProcesses, &pe32));

    memcpy(begin, &count, sizeof(DWORD));

    getchar();
    UnmapViewOfFile(begin);
    CloseHandle(hdata);
    CloseHandle(hProcesses);
    return 0;
}

Project 2:

#define _CRT_SECURE_NO_WARNINGS
#include <Windows.h>
#include <vector>
#include <stdio.h>

struct InfoProces {
    DWORD pid;
    DWORD ppid;
    char  exeName[256];
};

int main()
{
    HANDLE hdata = OpenFileMapping(FILE_MAP_ALL_ACCESS, false, "data");

    unsigned char* pdata = (unsigned char*)MapViewOfFile(hdata, FILE_MAP_READ, 0, 0, 0);
    if (pdata == NULL) {
        printf("cant get pointer to mapped file. err = %d", GetLastError());
        return -1;
    }
    unsigned char* begin = pdata;
    DWORD count = 0;
    memcpy(&count, pdata, sizeof(DWORD));
    pdata += sizeof(DWORD);
    std::vector<InfoProces>processes;
    processes.resize(count);
    memcpy(processes.data(), pdata, sizeof(InfoProces)*count);

    for (std::vector<InfoProces>::iterator i = processes.begin(); i < processes.end(); i++)
        printf("Process[%d](parinte[%d]): %s\n", i->pid, i->ppid, i->exeName);
    UnmapViewOfFile(begin);
    return 0;
}