/* _hurd_socket_server - Find the server for a socket domain.

   Copyright (C) 1991-2018 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

   <http://www.gnu.org/licenses/>.  */

#include <hurd.h>

#include <sys/socket.h>

#include <stdlib.h>

#include <string.h>

#include <hurd/paths.h>

#include <stdio.h>

#include <_itoa.h>

#include <cthreads.h>		/* For `struct mutex'.  */

#include "hurdmalloc.h"		/* XXX */

static struct mutex lock;

static file_t *servers;

static int max_domain = -1;

/* Return a port to the socket server for DOMAIN.

   Socket servers translate nodes in the directory _SERVERS_SOCKET

   (canonically /servers/socket).  These naming point nodes are named

   by the simplest decimal representation of the socket domain number,

   for example "/servers/socket/3".

   Socket servers are assumed not to change very often.

   The library keeps all the server socket ports it has ever looked up,

   and does not look them up in /servers/socket more than once.  */

socket_t

_hurd_socket_server (int domain, int dead)

{

  socket_t server;

  if (domain < 0)

    {

      errno = EAFNOSUPPORT;

      return MACH_PORT_NULL;

    }

  HURD_CRITICAL_BEGIN;

  __mutex_lock (&lock);

  if (domain > max_domain)

    {

      error_t save = errno;

      file_t *new = realloc (servers, (domain + 1) * sizeof (file_t));

      if (new != NULL)

	{

	  do

	    new[++max_domain] = MACH_PORT_NULL;

	  while (max_domain < domain);

	  servers = new;

	}

      else

	/* No space to cache the port; we will just fetch it anew below.  */

	errno = save;

    }

  if (dead && domain <= max_domain)

    {

      /* The user says the port we returned earlier (now in SERVERS[DOMAIN])

	 was dead.  Clear the cache and fetch a new one below.  */

      __mach_port_deallocate (__mach_task_self (), servers[domain]);

      servers[domain] = MACH_PORT_NULL;

    }

  if (domain > max_domain || servers[domain] == MACH_PORT_NULL)

    {

      char name[sizeof (_SERVERS_SOCKET) + 100];

      char *np = &name[sizeof (name)];

      *--np = '\0';

      np = _itoa (domain, np, 10, 0);

      *--np = '/';

      np -= sizeof (_SERVERS_SOCKET) - 1;

      memcpy (np, _SERVERS_SOCKET, sizeof (_SERVERS_SOCKET) - 1);

      server = __file_name_lookup (np, 0, 0);

      if (domain <= max_domain)

	servers[domain] = server;

    }

  else

    server = servers[domain];

  if (server == MACH_PORT_NULL && errno == ENOENT)

    /* If the server node is absent, we don't support that protocol.  */

    errno = EAFNOSUPPORT;

  __mutex_unlock (&lock);

  HURD_CRITICAL_END;

  return server;

}

static void

init (void)

{

  int i;

  __mutex_init (&lock);

  for (i = 0; i < max_domain; ++i)

    servers[i] = MACH_PORT_NULL;

  (void) &ini;;			/* Avoid "defined but not used" warning.  */

}

text_set_element (_hurd_preinit_hook, init);