1  /* Test opening a directory stream from a file descriptor.
       2     Copyright (C) 2009-2021 Free Software Foundation, Inc.
       3  
       4     This program is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU General Public License as published by
       6     the Free Software Foundation; either version 3 of the License, or
       7     (at your option) any later version.
       8  
       9     This program 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
      12     GNU General Public License for more details.
      13  
      14     You should have received a copy of the GNU General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  /* Written by Eric Blake <ebb9@byu.net>, 2009.  */
      18  
      19  #include <config.h>
      20  
      21  #include <dirent.h>
      22  
      23  #include "signature.h"
      24  SIGNATURE_CHECK (fdopendir, DIR *, (int));
      25  
      26  #include <errno.h>
      27  #include <fcntl.h>
      28  #include <unistd.h>
      29  
      30  #include "macros.h"
      31  
      32  int
      33  main (int argc _GL_UNUSED, char *argv[])
      34  {
      35    DIR *d;
      36    int fd;
      37  
      38    /* A non-directory cannot be turned into a directory stream.  */
      39    fd = open ("test-fdopendir.tmp", O_RDONLY | O_CREAT, 0600);
      40    ASSERT (0 <= fd);
      41    errno = 0;
      42    ASSERT (fdopendir (fd) == NULL);
      43    ASSERT (errno == ENOTDIR);
      44    ASSERT (close (fd) == 0);
      45    ASSERT (unlink ("test-fdopendir.tmp") == 0);
      46  
      47    /* A bad fd cannot be turned into a stream.  */
      48    {
      49      errno = 0;
      50      ASSERT (fdopendir (-1) == NULL);
      51      ASSERT (errno == EBADF);
      52    }
      53    {
      54      close (99);
      55      errno = 0;
      56      ASSERT (fdopendir (99) == NULL);
      57      ASSERT (errno == EBADF);
      58    }
      59  
      60    /* This should work.  */
      61    fd = open (".", O_RDONLY);
      62    ASSERT (0 <= fd);
      63    d = fdopendir (fd);
      64    ASSERT (d);
      65    /* fdopendir should not close fd.  */
      66    ASSERT (dup2 (fd, fd) == fd);
      67  
      68    /* Don't test dirfd here.  dirfd (d) must return fd on current POSIX
      69       platforms, but on pre-2008 platforms or on non-POSIX platforms
      70       dirfd (fd) might return some other descriptor, or -1, and gnulib
      71       does not work around this porting problem.  */
      72  
      73    ASSERT (closedir (d) == 0);
      74    /* Now we can guarantee that fd must be closed.  */
      75    errno = 0;
      76    ASSERT (dup2 (fd, fd) == -1);
      77    ASSERT (errno == EBADF);
      78  
      79    return 0;
      80  }