io/closefrom.c

   1 /* Close a range of file descriptors.
   2    Copyright (C) 2021 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 Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the 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    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <stdio.h>
  20 #include <unistd.h>
  21 #include <not-cancel.h>
  22
  23 void
  24 __closefrom (int lowfd)
  25 {
  26   int maxfd = __getdtablesize ();
  27   if (maxfd == -1)
  28     __fortify_fail ("closefrom failed to get the file descriptor table size");
  29
  30   for (int i = 0; i < maxfd; i++)
  31     if (i >= lowfd)
  32       __close_nocancel_nostatus (i);
  33 }
  34 weak_alias (__closefrom, closefrom)