/* Test that openat_safer leave standard fds alone.

   Copyright (C) 2009-2017 Free Software Foundation, Inc.

   This program is free software: you can redistribute it and/or modify

   it under the terms of the GNU General Public License as published by

   the Free Software Foundation; either version 3 of the License, or

   (at your option) any later version.

   This program is distributed in the hope that it will be useful,

   but WITHOUT ANY WARRANTY; without even the implied warranty of

   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License

   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */

/* Written by Eric Blake <ebb9@byu.net>, 2009.  */

#include <config.h>

#include "fcntl--.h"

#include <errno.h>

#include <stdio.h>

#include <sys/stat.h>

#include <unistd.h>

/* This test intentionally closes stderr.  So, we arrange to have fd 10

   (outside the range of interesting fd's during the test) set up to

   duplicate the original stderr.  */

#define BACKUP_STDERR_FILENO 10

#define ASSERT_STREAM myerr

#include "macros.h"

static FILE *myerr;

#define witness "test-openat-safer.txt"

int

main (void)

{

  int i;

  int j;

  int dfd;

  int fd;

  char buf[2];

  /* We close fd 2 later, so save it in fd 10.  */

  if (dup2 (STDERR_FILENO, BACKUP_STDERR_FILENO) != BACKUP_STDERR_FILENO

      || (myerr = fdopen (BACKUP_STDERR_FILENO, "w")) == NULL)

    return 2;

  /* Create handle for future use.  */

  dfd = openat (AT_FDCWD, ".", O_RDONLY);

  ASSERT (STDERR_FILENO < dfd);

  /* Create file for later checks.  */

  remove (witness);

  fd = openat (dfd, witness, O_WRONLY | O_CREAT | O_EXCL, 0600);

  ASSERT (STDERR_FILENO < fd);

  ASSERT (write (fd, "hi", 2) == 2);

  ASSERT (close (fd) == 0);

  /* Four iterations, with progressively more standard descriptors

     closed.  */

  for (i = -1; i <= STDERR_FILENO; i++)

    {

      ASSERT (fchdir (dfd) == 0);

      if (0 <= i)

        ASSERT (close (i) == 0);

      /* Execute once in ".", once in "..".  */

      for (j = 0; j <= 1; j++)

        {

          if (j)

            ASSERT (chdir ("..") == 0);

          /* Check for error detection.  */

          errno = 0;

          ASSERT (openat (AT_FDCWD, "", O_RDONLY) == -1);

          ASSERT (errno == ENOENT);

          errno = 0;

          ASSERT (openat (dfd, "", O_RDONLY) == -1);

          ASSERT (errno == ENOENT);

          errno = 0;

          ASSERT (openat (-1, ".", O_RDONLY) == -1);

          ASSERT (errno == EBADF);

          /* Check for trailing slash and /dev/null handling.  */

          errno = 0;

          ASSERT (openat (dfd, "nonexist.ent/", O_CREAT | O_RDONLY,

                          S_IRUSR | S_IWUSR) == -1);

          ASSERT (errno == ENOTDIR || errno == EISDIR || errno == ENOENT

                  || errno == EINVAL);

          errno = 0;

          ASSERT (openat (dfd, witness "/", O_RDONLY) == -1);

          ASSERT (errno == ENOTDIR || errno == EISDIR || errno == EINVAL);

          /* Using a bad directory is okay for absolute paths.  */

          fd = openat (-1, "/dev/null", O_WRONLY);

          ASSERT (STDERR_FILENO < fd);

          /* Using a non-directory is wrong for relative paths.  */

          errno = 0;

          ASSERT (openat (fd, ".", O_RDONLY) == -1);

          ASSERT (errno == EBADF || errno == ENOTDIR);

          ASSERT (close (fd) == 0);

          /* Check for our witness file.  */

          fd = openat (dfd, witness, O_RDONLY | O_NOFOLLOW);

          ASSERT (STDERR_FILENO < fd);

          ASSERT (read (fd, buf, 2) == 2);

          ASSERT (buf[0] == 'h' && buf[1] == 'i');

          ASSERT (close (fd) == 0);

        }

    }

  ASSERT (fchdir (dfd) == 0);

  ASSERT (unlink (witness) == 0);

  ASSERT (close (dfd) == 0);

  return 0;

}