socket_utils.cc

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/* Copyright (C) 2006,2007,2008,2015 Olly Betts
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <config.h>
#include "socket_utils.h"

#include <limits>

#include "realtime.h"
#include "safesyssocket.h"

using namespace std;

#ifdef __WIN32__
# include <io.h>
# include "msvcignoreinvalidparam.h"
# include <cerrno>

extern HANDLE fd_to_handle(int fd) {
    MSVCIgnoreInvalidParameter invalid_handle_value_is_ok;
    HANDLE handle = (HANDLE)_get_osfhandle(fd);
    if (handle != INVALID_HANDLE_VALUE) return handle;
    // On WIN32, a socket fd isn't the same as a non-socket fd - in fact it's
    // already a HANDLE!
    //
    // We need to convert to intptr_t first to suppress a compiler warning here
    // about casting an integer to a wider pointer type which is a reasonable
    // warning in general, but we check that the value isn't truncated before
    // we cast the HANDLE to int (see common/safesyssocket.h).
    return reinterpret_cast<HANDLE>(intptr_t(fd));
}

extern void close_fd_or_socket(int fd) {
    MSVCIgnoreInvalidParameter invalid_fd_value_is_ok;
    if (close(fd) == -1 && errno == EBADF) {
        // Bad file descriptor - probably because the fd is actually
        // a socket.
        closesocket(fd);
    }
}

#endif

void
set_socket_timeouts(int fd, double timeout)
{
    (void)fd;
    (void)timeout;
#if defined SO_SNDTIMEO || defined SO_RCVTIMEO
    {
# ifndef __WIN32__
        struct timeval t;
        RealTime::to_timeval(timeout, &t);
# else
        // Just to be different, it's a DWORD counting in milliseconds.
        DWORD t;
        if (usual(timeout < numeric_limits<DWORD>::max() / 1000))
            t = timeout * 1000;
        else
            t = numeric_limits<DWORD>::max();
# endif
# ifdef SO_SNDTIMEO
        (void)setsockopt(fd, SOL_SOCKET, SO_SNDTIMEO,
                         reinterpret_cast<char*>(&t), sizeof(t));
# endif
# ifdef SO_RCVTIMEO
        (void)setsockopt(fd, SOL_SOCKET, SO_RCVTIMEO,
                         reinterpret_cast<char*>(&t), sizeof(t));
# endif
    }
#endif
#ifdef SO_KEEPALIVE
    // SO_SNDTIMEO and SO_RCVTIMEO may be ignored even if they exist, so set
    // SO_KEEPALIVE anyway if it exists, as it will cause stuck connections to
    // time out eventually (though it may take ~2 hours).
    {
# ifndef __WIN32__
        int flag = 1;
# else
        DWORD flag = 1;
# endif
        (void)setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE,
                         reinterpret_cast<char*>(&flag), sizeof(flag));
    }
#endif
}