1  /* Test that directory streams leave standard fds alone.
       2     Copyright (C) 2009-2023 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 <errno.h>
      24  #include <fcntl.h>
      25  #include <stdio.h>
      26  #include <unistd.h>
      27  
      28  /* This test intentionally closes stderr.  So, we arrange to have fd 10
      29     (outside the range of interesting fd's during the test) set up to
      30     duplicate the original stderr.  */
      31  
      32  #define BACKUP_STDERR_FILENO 10
      33  #define ASSERT_STREAM myerr
      34  #include "macros.h"
      35  
      36  static FILE *myerr;
      37  
      38  int
      39  main (void)
      40  {
      41    int i;
      42    DIR *dp;
      43    /* The dirent-safer module works without the use of fdopendir (which
      44       would also pull in fchdir and openat); but if those modules were
      45       also used, we ensure that they are safe.  In particular, the
      46       gnulib version of fdopendir is unable to guarantee that
      47       dirfd(fdopendir(fd))==fd, but we can at least guarantee that if
      48       they are not equal, the fd returned by dirfd is safe.  */
      49  #if HAVE_FDOPENDIR || GNULIB_TEST_FDOPENDIR
      50    int dfd;
      51  #endif
      52  
      53    /* We close fd 2 later, so save it in fd 10.  */
      54    if (dup2 (STDERR_FILENO, BACKUP_STDERR_FILENO) != BACKUP_STDERR_FILENO
      55        || (myerr = fdopen (BACKUP_STDERR_FILENO, "w")) == NULL)
      56      return 2;
      57  
      58  #if HAVE_FDOPENDIR || GNULIB_TEST_FDOPENDIR
      59    dfd = open (".", O_RDONLY);
      60    ASSERT (STDERR_FILENO < dfd);
      61  #endif
      62  
      63    /* Four iterations, with progressively more standard descriptors
      64       closed.  */
      65    for (i = -1; i <= STDERR_FILENO; i++)
      66      {
      67        if (0 <= i)
      68          ASSERT (close (i) == 0);
      69        dp = opendir (".");
      70        ASSERT (dp);
      71        ASSERT (dirfd (dp) == -1 || STDERR_FILENO < dirfd (dp));
      72        ASSERT (closedir (dp) == 0);
      73  
      74  #if HAVE_FDOPENDIR || GNULIB_TEST_FDOPENDIR
      75        {
      76          int fd = fcntl (dfd, F_DUPFD_CLOEXEC, STDERR_FILENO + 1);
      77          ASSERT (STDERR_FILENO < fd);
      78          dp = fdopendir (fd);
      79          ASSERT (dp);
      80          ASSERT (dirfd (dp) == -1 || STDERR_FILENO < dirfd (dp));
      81          ASSERT (closedir (dp) == 0);
      82          errno = 0;
      83          ASSERT (close (fd) == -1);
      84          ASSERT (errno == EBADF);
      85        }
      86  #endif
      87      }
      88  
      89  #if HAVE_FDOPENDIR || GNULIB_TEST_FDOPENDIR
      90    ASSERT (close (dfd) == 0);
      91  #endif
      92  
      93    return 0;
      94  }