compat/sendmsg.c

   1 /*****************************************************************************
   2  * sendmsg.c: POSIX sendmsg() replacement
   3  *****************************************************************************
   4  * Copyright © 2017 VLC authors and VideoLAN
   5  * Copyright © 2016 Rémi Denis-Courmont
   6  *
   7  * Authors: Rémi Denis-Courmont
   8  *          Dennis Hamester <dhamester@jusst.de>
   9  *
  10  * This program is free software; you can redistribute it and/or modify it
  11  * under the terms of the GNU Lesser General Public License as published by
  12  * the Free Software Foundation; either version 2.1 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  18  * GNU Lesser General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU Lesser General Public License
  21  * along with this program; if not, write to the Free Software Foundation,
  22  * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
  23  *****************************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 # include <config.h>
  27 #endif
  28
  29 #ifdef _WIN32
  30 # include <errno.h>
  31 # include <stdlib.h>
  32 # include <winsock2.h>
  33
  34 ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
  35 {
  36     if (msg->msg_controllen != 0)
  37     {
  38         errno = ENOSYS;
  39         return -1;
  40     }
  41
  42     if (msg->msg_iovlen > IOV_MAX)
  43     {
  44         errno = EINVAL;
  45         return -1;
  46     }
  47
  48     WSABUF *buf = malloc(msg->msg_iovlen * sizeof (*buf));
  49     if (buf == NULL)
  50         return -1;
  51
  52     for (unsigned i = 0; i < msg->msg_iovlen; i++)
  53     {
  54         buf[i].len = msg->msg_iov[i].iov_len;
  55         buf[i].buf = (void *)msg->msg_iov[i].iov_base;
  56     }
  57
  58     DWORD sent;
  59
  60     int ret = WSASendTo(fd, buf, msg->msg_iovlen, &sent, flags,
  61                         msg->msg_name, msg->msg_namelen, NULL, NULL);
  62     free(buf);
  63
  64     if (ret == 0)
  65         return sent;
  66
  67     switch (WSAGetLastError())
  68     {
  69         case WSAEWOULDBLOCK:
  70             errno = EAGAIN;
  71             break;
  72     }
  73     return -1;
  74 }
  75
  76 #elif defined __native_client__
  77 #include <errno.h>
  78 #include <limits.h>
  79 #include <stdlib.h>
  80 #include <string.h>
  81 #ifdef HAVE_SYS_SOCKET_H
  82 #include <sys/socket.h>
  83 #endif
  84 #ifdef HAVE_SYS_UIO_H
  85 #include <sys/uio.h>
  86 #endif
  87
  88 ssize_t sendmsg(int fd, const struct msghdr *msg, int flags)
  89 {
  90     if (msg->msg_controllen != 0)
  91     {
  92         errno = ENOSYS;
  93         return -1;
  94     }
  95
  96     if ((msg->msg_iovlen <= 0) || (msg->msg_iovlen > IOV_MAX))
  97     {
  98         errno = EMSGSIZE;
  99         return -1;
 100     }
 101
 102     size_t full_size = 0;
 103     for (int i = 0; i < msg->msg_iovlen; ++i)
 104         full_size += msg->msg_iov[i].iov_len;
 105
 106     if (full_size > SSIZE_MAX) {
 107         errno = EINVAL;
 108         return -1;
 109     }
 110
 111     /**
 112      * We always allocate here, because whether send/sento allow NULL message or
 113      * not is unspecified.
 114      */
 115     char *data = malloc(full_size ? full_size : 1);
 116     if (!data) {
 117         errno = ENOMEM;
 118         return -1;
 119     }
 120
 121     size_t tmp = 0;
 122     for (int i = 0; i < msg->msg_iovlen; ++i) {
 123         memcpy(data + tmp, msg->msg_iov[i].iov_base, msg->msg_iov[i].iov_len);
 124         tmp += msg->msg_iov[i].iov_len;
 125     }
 126
 127     ssize_t res;
 128     if (msg->msg_name)
 129         res = sendto(fd, data, full_size, flags, msg->msg_name, msg->msg_namelen);
 130     else
 131         res = send(fd, data, full_size, flags);
 132
 133     free(data);
 134     return res;
 135 }
 136
 137 #else
 138 #error sendmsg not implemented on your platform!
 139 #endif