sysdeps/mach/hurd/getdtsz.c

   1 /* Copyright (C) 1991-2019 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, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <errno.h>
  19 #include <unistd.h>
  20 #include <hurd.h>
  21 #include <hurd/fd.h>
  22 #include <hurd/resource.h>
  23
  24 /* Return the maximum number of file descriptors the current process
  25    could possibly have (until it raises the resource limit).  */
  26 int
  27 __getdtablesize (void)
  28 {
  29   rlim_t limit;
  30
  31   HURD_CRITICAL_BEGIN;
  32   __mutex_lock (&_hurd_rlimit_lock);
  33   limit = _hurd_rlimits[RLIMIT_NOFILE].rlim_cur;
  34   __mutex_unlock (&_hurd_rlimit_lock);
  35   HURD_CRITICAL_END;
  36
  37   /* RLIM_INFINITY is not meaningful to our caller.  -1 is a good choice
  38      because `sysconf (_SC_OPEN_MAX)' calls us, and -1 from sysconf means
  39      "no determinable limit".  */
  40   return limit == RLIM_INFINITY ? -1 : (int) limit;
  41 }
  42
  43 weak_alias (__getdtablesize, getdtablesize)