hurd/hurdsock.c

   1 /* _hurd_socket_server - Find the server for a socket domain.
   2    Copyright (C) 1991, 92, 93, 94, 95, 97 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Library General Public License as
   7    published by the Free Software Foundation; either version 2 of the
   8    License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Library General Public License for more details.
  14
  15    You should have received a copy of the GNU Library General Public
  16    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <hurd.h>
  21 #include <sys/socket.h>
  22 #include <stdlib.h>
  23 #include <string.h>
  24 #include <hurd/paths.h>
  25 #include <stdio.h>
  26 #include "stdio-common/_itoa.h"
  27 #include <cthreads.h>           /* For `struct mutex'.  */
  28 #include "hurdmalloc.h"         /* XXX */
  29
  30 static struct mutex lock;
  31
  32 static file_t *servers;
  33 static int max_domain;
  34
  35 /* Return a port to the socket server for DOMAIN.
  36    Socket servers translate nodes in the directory _SERVERS_SOCKET
  37    (canonically /servers/socket).  These naming point nodes are named
  38    by the simplest decimal representation of the socket domain number,
  39    for example "/servers/socket/3".
  40
  41    Socket servers are assumed not to change very often.
  42    The library keeps all the server socket ports it has ever looked up,
  43    and does not look them up in /servers/socket more than once.  */
  44
  45 socket_t
  46 _hurd_socket_server (int domain, int dead)
  47 {
  48   socket_t server;
  49
  50   HURD_CRITICAL_BEGIN;
  51   __mutex_lock (&lock);
  52
  53   if (domain > max_domain)
  54     {
  55       error_t save = errno;
  56       file_t *new = realloc (servers, (domain + 1) * sizeof (file_t));
  57       if (new != NULL)
  58         {
  59           while (max_domain <= domain)
  60             new[max_domain++] = MACH_PORT_NULL;
  61           servers = new;
  62         }
  63       else
  64         /* No space to cache the port; we will just fetch it anew below.  */
  65         errno = save;
  66     }
  67
  68   if (dead && domain <= max_domain)
  69     {
  70       /* The user says the port we returned earlier (now in SERVERS[DOMAIN])
  71          was dead.  Clear the cache and fetch a new one below.  */
  72       __mach_port_deallocate (__mach_task_self (), servers[domain]);
  73       servers[domain] = MACH_PORT_NULL;
  74     }
  75
  76   if (domain > max_domain || servers[domain] == MACH_PORT_NULL)
  77     {
  78       char name[sizeof (_SERVERS_SOCKET) + 100];
  79       char *np = &name[sizeof (name)];
  80       *--np = '\0';
  81       np = _itoa (domain, np, 10, 0);
  82       *--np = '/';
  83       np -= sizeof (_SERVERS_SOCKET) - 1;
  84       memcpy (np, _SERVERS_SOCKET, sizeof (_SERVERS_SOCKET) - 1);
  85       server = __file_name_lookup (np, 0, 0);
  86       if (domain <= max_domain)
  87         servers[domain] = server;
  88     }
  89   else
  90     server = servers[domain];
  91
  92   if (server == MACH_PORT_NULL && errno == ENOENT)
  93     /* If the server node is absent, we don't support that protocol.  */
  94     errno = EPFNOSUPPORT;
  95
  96   __mutex_unlock (&lock);
  97   HURD_CRITICAL_END;
  98
  99   return server;
 100 }
 101 \f
 102 static void
 103 init (void)
 104 {
 105   int i;
 106
 107   __mutex_init (&lock);
 108
 109   for (i = 0; i < max_domain; ++i)
 110     servers[i] = MACH_PORT_NULL;
 111
 112   (void) &init;                 /* Avoid "defined but not used" warning.  */
 113 }
 114 text_set_element (_hurd_preinit_hook, init);