Socket.cc

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#include "Socket.hh"
 
#include "MSXException.hh" // FatalError
#include "utf8_checked.hh"
 
#include <bit>
#include <cerrno>
#include <cstring>
 
namespace openmsx {
 
std::string sock_error()
{
#ifdef _WIN32
        wchar_t* s = nullptr;
        FormatMessageW(
                FORMAT_MESSAGE_ALLOCATE_BUFFER |
                FORMAT_MESSAGE_FROM_SYSTEM |
                FORMAT_MESSAGE_IGNORE_INSERTS,
                nullptr, WSAGetLastError(), 0, reinterpret_cast<LPWSTR>(&s),
                0, nullptr);
        std::string result = utf8::utf16to8(s);
        LocalFree(s);
        return result;
#else
        return strerror(errno);
#endif
}
 
void sock_startup()
{
#ifdef _WIN32
        // MAKEWORD is #define'd as ((WORD)(((BYTE)(a))|(((WORD)((BYTE)(b)))<<8)))
        // but using that gives old-style-cast warnings
        WORD w = 1 | (1 << 8); // MAKEWORD(1, 1)
        WSAData wsaData;
        if (WSAStartup(w, &wsaData) != 0) {
                throw FatalError(sock_error());
        }
#else
        // nothing needed for unix
#endif
}
 
void sock_cleanup()
{
#ifdef _WIN32
        WSACleanup();
#else
        // nothing needed for unix
#endif
}
 
// close a connection
void sock_close(SOCKET sd)
{
#ifdef _WIN32
        closesocket(sd);
#else
        close(sd);
#endif
}
 
 
ptrdiff_t sock_recv(SOCKET sd, char* buf, size_t count)
{
        ptrdiff_t num = recv(sd, buf, count, 0);
        if (num >  0) return num; // normal case
        if (num == 0) return -1;  // socket was closed by client
#ifdef _WIN32
        // Something bad happened on the socket.  It could just be a
        // "would block" notification, or it could be something more
        // serious.  WSAEWOULDBLOCK can happen after select() says a
        // socket is readable under Win9x, it doesn't happen on
        // WinNT/2000 or on Unix.
        int err;
        int errLen = sizeof(err);
        getsockopt(sd, SOL_SOCKET, SO_ERROR, std::bit_cast<char*>(&err), &errLen);
        if (err == WSAEWOULDBLOCK) return 0;
        return -1;
#else
        if (errno == EWOULDBLOCK) return 0;
        return -1;
#endif
}
 
 
ptrdiff_t sock_send(SOCKET sd, const char* buf, size_t count)
{
        ptrdiff_t num = send(sd, buf, count, 0);
        if (num >= 0) return num; // normal case
#ifdef _WIN32
        int err;
        int errLen = sizeof(err);
        getsockopt(sd, SOL_SOCKET, SO_ERROR, std::bit_cast<char*>(&err), &errLen);
        if (err == WSAEWOULDBLOCK) return 0;
        return -1;
#else
        if (errno == EWOULDBLOCK) return 0;
        return -1;
#endif
}
 
} // namespace openmsx