在winhttp.dll中访问冲突
我试图在C ++中使用WinHTTP执行HTTP GET，但是在解析名称（在状态回调函数中获得WINHTTP_CALLBACK_STATUS_NAME_RESOLVED之后）的某个时刻它会崩溃。 我在winhttp.dll中遇到访问冲突。 这个callstack是：
winhttp.dll！HTTP_USER_REQUEST :: _ IndicateSocketAddress（）+ 0x221ed字节
winhttp.dll！HTTP_USER_REQUEST :: OnDnsNameResolved（）+ 0x24字节
winio.dll！WEBIO_REQUEST :: _ OnInformation（）+ 0x1c0c bytes webio.dll!_WaIndicateHttpRequestInformation@16（）+ 0x15a bytes webio.dll!_WaHttpInformationConnection@16（）+ 0x7a bytes
webio.dll!_WapTcpDnsQueryCompletionRoutine@12（）+ 0x2f字节
webio.dll!_WapCallDnsQueryCompletion@12（）+ 0x6d bytes webio.dll!_WaDnsResolutionWorker@8（）+ 0x157 bytes ntdll.dll!_TppSimplepExecuteCallback@8（）+ 0x7b bytes
ntdll.dll !TppWorkerThread@4（）+ 0x5a4字节
kernel32.dll！@ BaseThreadInitThunk @ 12（）+ 0x12字节
ntdll.dll！__ RtlUserThreadStart @ 8（）+ 0x27字节
ntdll.dll！__ RtlUserThreadStart @ 8（）+ 0x1b字节
相关代码是：
enum OnlineState
{
OnlineState_Idle,
OnlineState_Registering
};
static OnlineState g_OnlineState = OnlineState_Idle;
HINTERNET g_Request = 0;
HINTERNET g_Connection = 0;
unsigned char g_HTTPBuffer[1024];
void HTTPRequestComplete()
{
if(g_Request != 0)
{
WinHttpCloseHandle(g_Request);
g_Request = 0;
}
if(g_Connection != 0)
{
WinHttpCloseHandle(g_Connection);
g_Connection = 0;
}
g_OnlineState = OnlineState_Idle;
}
void HTTPAsyncCallback(HINTERNET hInternet, DWORD_PTR dwContext, DWORD dwInternetStatus, LPVOID lpvStatusInformation, DWORD dwStatusInformationLength)
{
switch(dwInternetStatus)
{
case WINHTTP_CALLBACK_STATUS_SENDREQUEST_COMPLETE:
{
// Get the response
if (!WinHttpReceiveResponse(g_Request, 0))
{
// Failed to get the response
HTTPRequestComplete();
return;
}
}
break;
case WINHTTP_CALLBACK_STATUS_HEADERS_AVAILABLE:
{
DWORD statusCode = 0;
DWORD statusCodeSize = sizeof(DWORD);
if (!WinHttpQueryHeaders(g_Request,
WINHTTP_QUERY_STATUS_CODE | WINHTTP_QUERY_FLAG_NUMBER,
WINHTTP_HEADER_NAME_BY_INDEX,
&statusCode,
&statusCodeSize,
WINHTTP_NO_HEADER_INDEX))
{
// Failed to query headers
HTTPRequestComplete();
return;
}
if (HTTP_STATUS_OK != statusCode)
{
// Error status
HTTPRequestComplete();
return;
}
if (!WinHttpReadData(g_Request,
g_HTTPBuffer,
sizeof(g_HTTPBuffer),
0))
{
// Error reading data
HTTPRequestComplete();
return;
}
}
break;
case WINHTTP_CALLBACK_STATUS_READ_COMPLETE:
{
if (dwStatusInformationLength > 0)
{
// Store the data
// Read the next data
if (!WinHttpReadData(g_Request,
g_HTTPBuffer,
sizeof(g_HTTPBuffer),
0))
{
// Error
HTTPRequestComplete();
return;
}
}
else
{
// Request completed OK
HTTPRequestComplete();
}
}
break;
default:
break;
}
}
// Online functionality
void Online_UpdateServer()
{
switch(g_OnlineState)
{
case OnlineState_Idle:
{
// Get our local ip address by connecting a local socket to a web address and reading the socket name
// Look up the address to connect to
addrinfo hints;
addrinfo* res = 0;
memset(&hints, 0, sizeof hints);
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_DGRAM;
getaddrinfo("www.google.com", "80", &hints, &res);
// Create the socket
int tempSocket = socket(res->ai_family, res->ai_socktype, res->ai_protocol);
unsigned int localAddress = 0;
if (tempSocket >= 0)
{
// Connect the socket
connect(tempSocket, res->ai_addr, res->ai_addrlen);
// Get the socket name (our local ip address)
sockaddr_in localName;
memset(&localName, 0, sizeof(localName));
int bufferSize = sizeof(localName);
if(getsockname(tempSocket, (sockaddr*)&localName, &bufferSize) == 0)
{
// Get the IP address
localAddress = localName.sin_addr.S_un.S_addr;
}
closesocket(tempSocket);
}
// Connect
g_Connection = WinHttpConnect(g_Internet, L"www.google.com", INTERNET_DEFAULT_PORT, 0);
// Open the request
std::wstringstream urlString;
urlString << L"/";
std::wstring tempString = urlString.str();
const wchar_t* wurlString = tempString.c_str();
g_Request = WinHttpOpenRequest(g_Connection, 0, wurlString, 0, WINHTTP_NO_REFERER, WINHTTP_DEFAULT_ACCEPT_TYPES, 0);
// Install the status callback function.
if(WINHTTP_INVALID_STATUS_CALLBACK == WinHttpSetStatusCallback(g_Request, (WINHTTP_STATUS_CALLBACK)HTTPAsyncCallback, WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS, NULL))
{
OutputDebugString(L"Error");
}
// Send the request
if(!WinHttpSendRequest(g_Request, WINHTTP_NO_ADDITIONAL_HEADERS, 0, WINHTTP_NO_REQUEST_DATA, 0, 0, 0))
{
OutputDebugString(L"Error");
}
// Log that we're registering
g_OnlineState = OnlineState_Registering;
}
break;
case OnlineState_Registering:
{
// Don't do anything, as we're currently registering
}
break;
default:
break;
}
}
g_Internet是这样初始化的：
// Initialise HTTP
g_Internet = WinHttpOpen(L"Boomba", WINHTTP_ACCESS_TYPE_DEFAULT_PROXY, WINHTTP_NO_PROXY_NAME, WINHTTP_NO_PROXY_BYPASS, WINHTTP_FLAG_ASYNC);
据我所知，我正在初始化并正确使用WinHTTP，并且一切似乎都会恢复正常而没有错误。 该回调被调用两次，第一次使用WINHTTP_CALLBACK_STATUS_RESOLVING_NAME，然后使用WINHTTP_CALLBACK_STATUS_NAME_RESOLVED，之后我得到访问冲突：
0xC0000005：访问冲突读取位置0x00000014
位置变化，各种各样的事情，所以我认为它看起来可能是一个线程问题，但我不知道什么可能是问题。 有任何想法吗？ （我在Windows 7 64位上运行）。
if (WINHTTP_INVALID_STATUS_CALLBACK == WinHttpSetStatusCallback(
g_Request,
(WINHTTP_STATUS_CALLBACK)HTTPAsyncCallback, // <=== evil
WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS,
NULL))
编译器最初抱怨你的函数和需要的函数指针类型不匹配。 通过关闭编译器来解决问题。 但是这并没有解决问题。 现在你给自己买了一个真正的问题，一个损坏的堆栈。 很难诊断。
回调函数必须声明为__stdcall，而不是默认的__cdecl调用约定。 Windows头文件使用CALLBACK宏。 固定：
void CALLBACK HTTPAsyncCallback(/* etc*/)
当然，删除该演员。
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