/* Test that dup_safer leaves standard fds alone.

   Copyright (C) 2009-2018 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 <https://www.gnu.org/licenses/>.  */

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

#include <config.h>

#include "unistd--.h"

#include <fcntl.h>

#include <errno.h>

#include <stdbool.h>

#include <stdio.h>

#include <unistd.h>

#include "binary-io.h"

#include "cloexec.h"

#if defined _WIN32 && ! defined __CYGWIN__

/* Get declarations of the native Windows API functions.  */

# define WIN32_LEAN_AND_MEAN

# include <windows.h>

/* Get _get_osfhandle.  */

# if GNULIB_MSVC_NOTHROW

#  include "msvc-nothrow.h"

# else

#  include <io.h>

# endif

#endif

#if !O_BINARY

# define setmode(f,m) zero ()

static int zero (void) { return 0; }

#endif

/* 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;

/* Return true if FD is open.  */

static bool

is_open (int fd)

{

#if defined _WIN32 && ! defined __CYGWIN__

  /* On native Windows, the initial state of unassigned standard file

     descriptors is that they are open but point to an

     INVALID_HANDLE_VALUE, and there is no fcntl.  */

  return (HANDLE) _get_osfhandle (fd) != INVALID_HANDLE_VALUE;

#else

# ifndef F_GETFL

#  error Please port fcntl to your platform

# endif

  return 0 <= fcntl (fd, F_GETFL);

#endif

}

/* Return true if FD is open and inheritable across exec/spawn.  */

static bool

is_inheritable (int fd)

{

#if defined _WIN32 && ! defined __CYGWIN__

  /* On native Windows, the initial state of unassigned standard file

     descriptors is that they are open but point to an

     INVALID_HANDLE_VALUE, and there is no fcntl.  */

  HANDLE h = (HANDLE) _get_osfhandle (fd);

  DWORD flags;

  if (h == INVALID_HANDLE_VALUE || GetHandleInformation (h, &flags) == 0)

    return 0;

  return (flags & HANDLE_FLAG_INHERIT) != 0;

#else

# ifndef F_GETFD

#  error Please port fcntl to your platform

# endif

  int i = fcntl (fd, F_GETFD);

  return 0 <= i && (i & FD_CLOEXEC) == 0;

#endif

}

/* Return true if FD is open in the given MODE, which is either

   O_TEXT or O_BINARY.  */

static bool

is_mode (int fd, int mode)

{

  int value = setmode (fd, O_BINARY);

  setmode (fd, value);

  return mode == value;

}

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

int

main (void)

{

  int i;

  int fd;

  int bad_fd = getdtablesize ();

  /* 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 file for later checks.  */

  fd = creat (witness, 0600);

  ASSERT (STDERR_FILENO < fd);

  /* Four iterations, with progressively more standard descriptors

     closed.  */

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

    {

      if (0 <= i)

        ASSERT (close (i) == 0);

      /* Detect errors.  */

      errno = 0;

      ASSERT (dup (-1) == -1);

      ASSERT (errno == EBADF);

      errno = 0;

      ASSERT (dup (bad_fd) == -1);

      ASSERT (errno == EBADF);

      close (fd + 1);

      errno = 0;

      ASSERT (dup (fd + 1) == -1);

      ASSERT (errno == EBADF);

      /* Preserve text vs. binary.  */

      setmode (fd, O_BINARY);

      ASSERT (dup (fd) == fd + 1);

      ASSERT (is_open (fd + 1));

      ASSERT (is_inheritable (fd + 1));

      ASSERT (is_mode (fd + 1, O_BINARY));

      ASSERT (close (fd + 1) == 0);

      setmode (fd, O_TEXT);

      ASSERT (dup (fd) == fd + 1);

      ASSERT (is_open (fd + 1));

      ASSERT (is_inheritable (fd + 1));

      ASSERT (is_mode (fd + 1, O_TEXT));

      /* Create cloexec copy.  */

      ASSERT (close (fd + 1) == 0);

      ASSERT (fd_safer_flag (dup_cloexec (fd), O_CLOEXEC) == fd + 1);

      ASSERT (set_cloexec_flag (fd + 1, true) == 0);

      ASSERT (is_open (fd + 1));

      ASSERT (!is_inheritable (fd + 1));

      ASSERT (close (fd) == 0);

      /* dup always creates inheritable copies.  Also, check that

         earliest slot past std fds is used.  */

      ASSERT (dup (fd + 1) == fd);

      ASSERT (is_open (fd));

      ASSERT (is_inheritable (fd));

      ASSERT (close (fd + 1) == 0);

    }

  /* Cleanup.  */

  ASSERT (close (fd) == 0);

  ASSERT (unlink (witness) == 0);

  return 0;

}