text: /* Copyright (C) 1994-2020 Free Software Foundation, Inc.
     This file is part of the GNU C Library.
  
     The GNU C Library is free software; you can redistribute it and/or
     modify it under the terms of the GNU Lesser General Public
     License as published by the Free Software Foundation; either
     version 2.1 of the License, or (at your option) any later version.
  
     The GNU C Library 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
     Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public
     License along with the GNU C Library; if not, see
     <https://www.gnu.org/licenses/>.  */
  
  #include <errno.h>
  #include <string.h>
  #include <sys/socket.h>
  #include <hurd.h>
  #include <hurd/fd.h>
  #include <hurd/socket.h>
  
  /* Read N bytes into BUF through socket FD.
     If ADDR is not NULL, fill in *ADDR_LEN bytes of it with tha address of
     the sender, and store the actual size of the address in *ADDR_LEN.
     Returns the number of bytes read or -1 for errors.  */
  ssize_t
  __recvfrom (int fd, void *buf, size_t n, int flags, __SOCKADDR_ARG addrarg,
  	    socklen_t *addr_len)
  {
    error_t err;
    mach_port_t addrport;
    char *bufp = buf;
    mach_msg_type_number_t nread = n;
    mach_port_t *ports;
    mach_msg_type_number_t nports = 0;
    char *cdata = NULL;
    mach_msg_type_number_t clen = 0;
    struct sockaddr *addr = addrarg.__sockaddr__;
  
    if (err = HURD_DPORT_USE (fd, __socket_recv (port, &addrport,
  					       flags, &bufp, &nread,
  					       &ports, &nports,
  					       &cdata, &clen,
  					       &flags,
  					       n)))
      return __hurd_sockfail (fd, flags, err);
  
    /* Get address data for the returned address port if requested.  */
    if (addr != NULL && addrport != MACH_PORT_NULL)
      {
        char *buf = (char *) addr;
        mach_msg_type_number_t buflen = *addr_len;
        int type;
  
        err = __socket_whatis_address (addrport, &type, &buf, &buflen);
        if (err == EOPNOTSUPP)
  	/* If the protocol server can't tell us the address, just return a
  	   zero-length one.  */
  	{
  	  buf = (char *)addr;
  	  buflen = 0;
  	  err = 0;
  	}
  
        if (err)
  	{
  	  __mach_port_deallocate (__mach_task_self (), addrport);
  	  return __hurd_sockfail (fd, flags, err);
  	}
  
        if (*addr_len > buflen)
  	*addr_len = buflen;
  
        if (buf != (char *) addr)
  	{
  	  memcpy (addr, buf, *addr_len);
  	  __vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
  	}
  
        if (buflen > 0)
  	addr->sa_family = type;
      }
    else if (addr_len != NULL)
      *addr_len = 0;
  
    __mach_port_deallocate (__mach_task_self (), addrport);
  
    /* Toss control data; we don't care.  */
    __vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);
  
    if (bufp != buf)
      {
        memcpy (buf, bufp, nread);
        __vm_deallocate (__mach_task_self (), (vm_address_t) bufp, nread);
      }
  
    return nread;
  }
  
  weak_alias (__recvfrom, recvfrom)
  