sysdeps/mach/hurd/getdtsz.c

   1 /* Copyright (C) 1991,92,93,94,95,97,2000 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
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    02111-1307 USA.  */
  18
  19 #include <errno.h>
  20 #include <unistd.h>
  21 #include <hurd.h>
  22 #include <hurd/fd.h>
  23 #include <hurd/resource.h>
  24
  25 /* Return the maximum number of file descriptors the current process
  26    could possibly have (until it raises the resource limit).  */
  27 int
  28 __getdtablesize ()
  29 {
  30   rlim_t limit;
  31
  32   HURD_CRITICAL_BEGIN;
  33   __mutex_lock (&_hurd_rlimit_lock);
  34   limit = _hurd_rlimits[RLIMIT_NOFILE].rlim_cur;
  35   __mutex_unlock (&_hurd_rlimit_lock);
  36   HURD_CRITICAL_END;
  37
  38   /* RLIM_INFINITY is not meaningful to our caller.  -1 is a good choice
  39      because `sysconf (_SC_OPEN_MAX)' calls us, and -1 from sysconf means
  40      "no determinable limit".  */
  41   return limit == RLIM_INFINITY ? -1 : (int) limit;
  42 }
  43
  44 weak_alias (__getdtablesize, getdtablesize)