/* Example of Local-Namespace Sockets

   Copyright (C) 1991-2018 Free Software Foundation, Inc.

   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, if not, see <http://www.gnu.org/licenses/>.

*/

#include <stddef.h>

#include <stdio.h>

#include <errno.h>

#include <stdlib.h>

#include <string.h>

#include <sys/socket.h>

#include <sys/un.h>

int

make_named_socket (const char *filename)

{

  struct sockaddr_un name;

  int sock;

  size_t size;

  /* Create the socket.  */

  sock = socket (PF_LOCAL, SOCK_DGRAM, 0);

  if (sock < 0)

    {

      perror ("socket");

      exit (EXIT_FAILURE);

    }

  /* Bind a name to the socket.  */

  name.sun_family = AF_LOCAL;

  strncpy (name.sun_path, filename, sizeof (name.sun_path));

  name.sun_path[sizeof (name.sun_path) - 1] = '\0';

  /* The size of the address is

     the offset of the start of the filename,

     plus its length (not including the terminating null byte).

     Alternatively you can just do:

     size = SUN_LEN (&name);

  */

  size = (offsetof (struct sockaddr_un, sun_path)

	  + strlen (name.sun_path));

  if (bind (sock, (struct sockaddr *) &name, size) < 0)

    {

      perror ("bind");

      exit (EXIT_FAILURE);

    }

  return sock;

}