io/close_range.c

   1 /* Close a range of file descriptors.
   2    Copyright (C) 2021-2022 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 <errno.h>
  20 #include <not-cancel.h>
  21 #include <unistd.h>
  22
  23 /* Close the file descriptors from FIRST up to LAST, inclusive.  */
  24 int
  25 __close_range (unsigned int first, unsigned int last,
  26                int flags)
  27 {
  28   if (first > last || flags != 0)
  29     {
  30       __set_errno (EINVAL);
  31       return -1;
  32     }
  33
  34   int maxfd = __getdtablesize ();
  35   if (maxfd == -1)
  36     return -1;
  37
  38   for (int i = first; i <= last && i < maxfd; i++)
  39     __close_nocancel_nostatus (i);
  40
  41   return 0;
  42 }
  43 libc_hidden_def (__close_range)
  44 weak_alias (__close_range, close_range)