sysdeps/unix/sysv/linux/fdopendir.c

   1 /* Copyright (C) 2005-2023 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    <https://www.gnu.org/licenses/>.  */
  17
  18 #include <dirent.h>
  19 #include <errno.h>
  20 #include <fcntl.h>
  21 #include <stddef.h>
  22 #include <sys/stat.h>
  23
  24 #include <not-cancel.h>
  25
  26
  27 DIR *
  28 __fdopendir (int fd)
  29 {
  30   struct __stat64_t64 statbuf;
  31
  32   if (__glibc_unlikely (__fstat64_time64 (fd, &statbuf) < 0))
  33     return NULL;
  34   if (__glibc_unlikely (! S_ISDIR (statbuf.st_mode)))
  35     {
  36       __set_errno (ENOTDIR);
  37       return NULL;
  38     }
  39
  40   int flags = __fcntl64_nocancel (fd, F_GETFL);
  41   if (__glibc_unlikely (flags == -1))
  42     return NULL;
  43   /* Fail early for descriptors opened with O_PATH.  */
  44   if (__glibc_unlikely (flags & O_PATH))
  45     {
  46       __set_errno (EBADF);
  47       return NULL;
  48     }
  49   /* Make sure the descriptor allows for reading.  */
  50   if (__glibc_unlikely ((flags & O_ACCMODE) == O_WRONLY))
  51     {
  52       __set_errno (EINVAL);
  53       return NULL;
  54     }
  55
  56   return __alloc_dir (fd, false, flags, &statbuf);
  57 }
  58 weak_alias (__fdopendir, fdopendir)