compat/recvmsg.c

   1 /*****************************************************************************
   2  * recvmsg.c: POSIX recvmsg() replacement
   3  *****************************************************************************
   4  * Copyright © 2016 Rémi Denis-Courmont
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU Lesser General Public License as published by
   8  * the Free Software Foundation; either version 2.1 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with this program; if not, write to the Free Software Foundation,
  18  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  19  *****************************************************************************/
  20
  21 #ifdef HAVE_CONFIG_H
  22 # include <config.h>
  23 #endif
  24
  25 #ifdef _WIN32
  26 # include <errno.h>
  27 # include <stdlib.h>
  28 # include <winsock2.h>
  29
  30 ssize_t recvmsg(int fd, struct msghdr *msg, int flags)
  31 {
  32     if (msg->msg_controllen != 0)
  33     {
  34         errno = ENOSYS;
  35         return -1;
  36     }
  37
  38     if (msg->msg_iovlen > IOV_MAX)
  39     {
  40         errno = EINVAL;
  41         return -1;
  42     }
  43
  44     WSABUF *buf = malloc(msg->msg_iovlen * sizeof (*buf));
  45     if (buf == NULL)
  46         return -1;
  47
  48     for (unsigned i = 0; i < msg->msg_iovlen; i++)
  49     {
  50         buf[i].len = msg->msg_iov[i].iov_len;
  51         buf[i].buf = msg->msg_iov[i].iov_base;
  52     }
  53
  54     DWORD dwFlags = flags;
  55     INT fromlen = msg->msg_namelen;
  56     DWORD rcvd;
  57     int ret;
  58     if (fromlen)
  59         ret = WSARecvFrom(fd, buf, msg->msg_iovlen, &rcvd, &dwFlags,
  60                           msg->msg_name, &fromlen, NULL, NULL);
  61     else
  62         ret = WSARecv(fd, buf, msg->msg_iovlen, &rcvd, &dwFlags,
  63                       NULL, NULL);
  64     free(buf);
  65
  66     if (ret == 0)
  67     {
  68         msg->msg_namelen = fromlen;
  69         msg->msg_flags = dwFlags;
  70         return rcvd;
  71     }
  72
  73     switch (WSAGetLastError())
  74     {
  75         case WSAEWOULDBLOCK:
  76             errno = EAGAIN;
  77             break;
  78     }
  79     return -1;
  80 }
  81 #endif