Question

我尝试使用Microsoft SDK库从IcmpSendEcho 加载iphlpapi.dll而不是。我在Windows 7 x64上使用GCC 4.8.1（win32）。我这样试过：

创建必需的结构并定义常量
获取DLL函数的指针
调用DLL函数

我汇总了一个展示我问题的小例子：

#include <windows.h>
#include <stdio.h>
#include <stdint.h>

typedef struct {
  union {
    struct {
      u_char s_b1,s_b2,s_b3,s_b4;
    } S_un_b;
    struct {
      u_short s_w1,s_w2;
    } S_un_w;
    u_long S_addr;
  } S_un;
} IPAddr;


#define IP_FLAG_REVERSE 0x01
#define IP_FLAG_DF      0x02

typedef struct {
  UCHAR  Ttl;
  UCHAR  Tos;
  UCHAR  Flags;
  UCHAR  OptionsSize;
  PUCHAR OptionsData;
} IP_OPTION_INFORMATION;


typedef struct {
  IPAddr                       Address;
  ULONG                        Status;
  ULONG                        RoundTripTime;
  USHORT                       DataSize;
  USHORT                       Reserved;
  PVOID                        Data;
  IP_OPTION_INFORMATION        Options;
} ICMP_ECHO_REPLY;


typedef HANDLE (*IcmpCreateFile_t)();

typedef BOOL (*IcmpCloseHandle_t)(
    HANDLE IcmpHandle // _In_  HANDLE IcmpHandle
);

typedef DWORD (*IcmpSendEcho_t)(
    HANDLE IcmpHandle,  // _In_      HANDLE IcmpHandle,
    IPAddr dst,         // _In_      IPAddr DestinationAddress,
    void * RequestData, // _In_      LPVOID RequestData,
    WORD RequestSize,   // _In_      WORD RequestSize,
    IP_OPTION_INFORMATION * RequestOptions, // _In_opt_  PIP_OPTION_INFORMATION RequestOptions,
    void * ReplyBuffer, // _Out_     LPVOID ReplyBuffer,
    DWORD ReplySize,    // _In_      DWORD ReplySize,
    DWORD Timeout       // _In_      DWORD Timeout
);


HINSTANCE hIPHLPAPI = NULL;
IcmpCreateFile_t  IcmpCreateFile  = NULL;
IcmpCloseHandle_t IcmpCloseHandle = NULL;
IcmpSendEcho_t    IcmpSendEcho    = NULL;

HANDLE hIcmpFile;

int icmp_init() {
    hIPHLPAPI = LoadLibrary("iphlpapi.dll");
    if(hIPHLPAPI == NULL) return 0;

    IcmpCreateFile = (IcmpCreateFile_t) GetProcAddress(hIPHLPAPI, "IcmpCreateFile");
    if(IcmpCreateFile == NULL) return 0;

    IcmpCloseHandle = (IcmpCloseHandle_t) GetProcAddress(hIPHLPAPI, "IcmpCloseHandle");
    if(IcmpCloseHandle == NULL) return 0;

    IcmpSendEcho = (IcmpSendEcho_t) GetProcAddress(hIPHLPAPI, "IcmpSendEcho");
    if(IcmpSendEcho == NULL) return 0;

    hIcmpFile = IcmpCreateFile();
    if(!hIcmpFile) return 0;

    return 1;
}

int icmp_ping(uint32_t ip) {
    // Echo request data
    int dataSize = 32;
    void * data = malloc(dataSize);

    // Reply buffer
    int replySize = sizeof(ICMP_ECHO_REPLY) + 128;
    void * replyBuffer = malloc(replySize);
    if(replyBuffer == NULL) return 0;

    // Send echo request and wait for reply
    IPAddr dst;
    dst.S_un.S_addr = ip;
    printf("Calling IcmpSendEcho\n");
    DWORD dwRetVal = IcmpSendEcho(hIcmpFile, dst, data, dataSize, NULL, replyBuffer, replySize, 1000);
    if(dwRetVal == 0) return 0;

    ICMP_ECHO_REPLY *echoreply = (ICMP_ECHO_REPLY *) replyBuffer;
    printf("Status = %ld\n", echoreply->Status);

    free(replyBuffer);

    return 0;
}

int icmp_free() {
    FreeLibrary(hIPHLPAPI);
    return 1;
}

int main(int argc, char *argv[]) {
    if(icmp_init()) {
        int pret = icmp_ping(2915201282 /* google.com */);
        printf("icmp_ping returned %d\n", pret);
        icmp_free();
    }
}

我使用gcc -o icmp_test.exe icmpt_test.c编译此示例。它打印“Calling IcmpSendEcho”并崩溃（见下文）。

这不是“真正的”代码，但它以同样的方式失败。对IcmpCreateFile的调用成功，但调用IcmpSendEcho会使程序崩溃并使Windows显示“...已停止工作”。

我认为问题可能与错误的指针有关，但我找不到问题。

Answer 1

使用GetProcAddress同步链接库时，需要确保匹配签名和调用约定。虽然签名通常很容易纠正，但很容易忘记考虑calling convention。

Windows中的系统模块始终使用__stdcall，这也可以通过WINAPI预处理器宏获得。要修复代码以便编译器为函数调用生成适当的指令，您需要更新以下函数指针类型以包含适当的调用约定：

typedef HANDLE (WINAPI* IcmpCreateFile_t)();

typedef BOOL (WINAPI* IcmpCloseHandle_t)(
    HANDLE IcmpHandle // _In_  HANDLE IcmpHandle
);

typedef DWORD (WINAPI* IcmpSendEcho_t)(
    HANDLE IcmpHandle,  // _In_      HANDLE IcmpHandle,
    IPAddr dst,         // _In_      IPAddr DestinationAddress,
    void * RequestData, // _In_      LPVOID RequestData,
    WORD RequestSize,   // _In_      WORD RequestSize,
    IP_OPTION_INFORMATION * RequestOptions, // _In_opt_  PIP_OPTION_INFORMATION
    RequestOptions,
    void * ReplyBuffer, // _Out_     LPVOID ReplyBuffer,
    DWORD ReplySize,    // _In_      DWORD ReplySize,
    DWORD Timeout       // _In_      DWORD Timeout
);

GCC在系统DLL调用期间编译Win32程序崩溃

1 个答案: