sysdeps/mach/hurd/recvmsg.c

   1 /* Copyright (C) 2001-2015 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If
  16    not, see <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <string.h>
  20 #include <sys/socket.h>
  21
  22 #include <hurd.h>
  23 #include <hurd/fd.h>
  24 #include <hurd/socket.h>
  25
  26 /* Receive a message as described by MESSAGE from socket FD.
  27    Returns the number of bytes read or -1 for errors.  */
  28 ssize_t
  29 __libc_recvmsg (int fd, struct msghdr *message, int flags)
  30 {
  31   error_t err;
  32   addr_port_t aport;
  33   char *data = NULL;
  34   mach_msg_type_number_t len = 0;
  35   mach_port_t *ports;
  36   mach_msg_type_number_t nports = 0;
  37   char *cdata = NULL;
  38   mach_msg_type_number_t clen = 0;
  39   size_t amount;
  40   char *buf;
  41   int i;
  42
  43   /* Find the total number of bytes to be read.  */
  44   amount = 0;
  45   for (i = 0; i < message->msg_iovlen; i++)
  46     {
  47       amount += message->msg_iov[i].iov_len;
  48
  49       /* As an optimization, we set the initial values of DATA and LEN
  50          from the first non-empty iovec.  This kicks-in in the case
  51          where the whole packet fits into that iovec buffer.  */
  52       if (data == NULL && message->msg_iov[i].iov_len > 0)
  53         {
  54           data = message->msg_iov[i].iov_base;
  55           len = message->msg_iov[i].iov_len;
  56         }
  57     }
  58
  59   buf = data;
  60   if (err = HURD_DPORT_USE (fd, __socket_recv (port, &aport,
  61                                                flags, &data, &len,
  62                                                &ports, &nports,
  63                                                &cdata, &clen,
  64                                                &message->msg_flags, amount)))
  65     return __hurd_sockfail (fd, flags, err);
  66
  67   if (message->msg_name != NULL)
  68     {
  69       char *buf = message->msg_name;
  70       mach_msg_type_number_t buflen = message->msg_namelen;
  71       int type;
  72
  73       err = __socket_whatis_address (aport, &type, &buf, &buflen);
  74       if (err == EOPNOTSUPP)
  75         /* If the protocol server can't tell us the address, just return a
  76            zero-length one.  */
  77         {
  78           buf = message->msg_name;
  79           buflen = 0;
  80           err = 0;
  81         }
  82
  83       if (err)
  84         {
  85           __mach_port_deallocate (__mach_task_self (), aport);
  86           return __hurd_sockfail (fd, flags, err);
  87         }
  88
  89       if (message->msg_namelen > buflen)
  90         message->msg_namelen = buflen;
  91
  92       if (buf != message->msg_name)
  93         {
  94           memcpy (message->msg_name, buf, message->msg_namelen);
  95           __vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
  96         }
  97
  98       if (buflen > 0)
  99         ((struct sockaddr *) message->msg_name)->sa_family = type;
 100     }
 101
 102   __mach_port_deallocate (__mach_task_self (), aport);
 103
 104   if (buf == data)
 105     buf += len;
 106   else
 107     {
 108       /* Copy the data into MSG.  */
 109       if (len > amount)
 110         message->msg_flags |= MSG_TRUNC;
 111       else
 112         amount = len;
 113
 114       buf = data;
 115       for (i = 0; i < message->msg_iovlen; i++)
 116         {
 117 #define min(a, b)       ((a) > (b) ? (b) : (a))
 118           size_t copy = min (message->msg_iov[i].iov_len, amount);
 119
 120           memcpy (message->msg_iov[i].iov_base, buf, copy);
 121
 122           buf += copy;
 123           amount -= copy;
 124           if (len == 0)
 125             break;
 126         }
 127
 128       __vm_deallocate (__mach_task_self (), (vm_address_t) data, len);
 129     }
 130
 131   /* Copy the control message into MSG.  */
 132   if (clen > message->msg_controllen)
 133     message->msg_flags |= MSG_CTRUNC;
 134   else
 135     message->msg_controllen = clen;
 136   memcpy (message->msg_control, cdata, message->msg_controllen);
 137
 138   __vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);
 139
 140   return (buf - data);
 141 }
 142
 143 weak_alias (__libc_recvmsg, recvmsg)
 144 weak_alias (__libc_recvmsg, __recvmsg)