/* Test duplicating file descriptors.

   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 <unistd.h>

#include "signature.h"

SIGNATURE_CHECK (dup2, int, (int, int));

#include <errno.h>

#include <fcntl.h>

#if HAVE_SYS_RESOURCE_H

# include <sys/resource.h>

#endif

#include "binary-io.h"

#if GNULIB_TEST_CLOEXEC

# include "cloexec.h"

#endif

#if (defined _WIN32 || 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

#include "macros.h"

/* Return non-zero if FD is open.  */

static int

is_open (int fd)

{

#if (defined _WIN32 || 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

}

#if GNULIB_TEST_CLOEXEC

/* Return non-zero if FD is open and inheritable across exec/spawn.  */

static int

is_inheritable (int fd)

{

# if (defined _WIN32 || 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

}

#endif /* GNULIB_TEST_CLOEXEC */

#if !O_BINARY

# define setmode(f,m) zero ()

static int zero (void) { return 0; }

#endif

/* Return non-zero if FD is open in the given MODE, which is either

   O_TEXT or O_BINARY.  */

static int

is_mode (int fd, int mode)

{

  int value = setmode (fd, O_BINARY);

  setmode (fd, value);

  return mode == value;

}

int

main (void)

{

  const char *file = "test-dup2.tmp";

  char buffer[1];

  int bad_fd = getdtablesize ();

  int fd = open (file, O_CREAT | O_TRUNC | O_RDWR, 0600);

  /* Assume std descriptors were provided by invoker.  */

  ASSERT (STDERR_FILENO < fd);

  ASSERT (is_open (fd));

  /* Ignore any other fd's leaked into this process.  */

  close (fd + 1);

  close (fd + 2);

  ASSERT (!is_open (fd + 1));

  ASSERT (!is_open (fd + 2));

  /* Assigning to self must be a no-op.  */

  ASSERT (dup2 (fd, fd) == fd);

  ASSERT (is_open (fd));

  /* The source must be valid.  */

  errno = 0;

  ASSERT (dup2 (-1, fd) == -1);

  ASSERT (errno == EBADF);

  close (99);

  errno = 0;

  ASSERT (dup2 (99, fd) == -1);

  ASSERT (errno == EBADF);

  errno = 0;

  ASSERT (dup2 (AT_FDCWD, fd) == -1);

  ASSERT (errno == EBADF);

  ASSERT (is_open (fd));

  /* If the source is not open, then the destination is unaffected.  */

  errno = 0;

  ASSERT (dup2 (fd + 1, fd + 1) == -1);

  ASSERT (errno == EBADF);

  ASSERT (!is_open (fd + 1));

  errno = 0;

  ASSERT (dup2 (fd + 1, fd) == -1);

  ASSERT (errno == EBADF);

  ASSERT (is_open (fd));

  /* The destination must be valid.  */

  errno = 0;

  ASSERT (dup2 (fd, -2) == -1);

  ASSERT (errno == EBADF);

  if (bad_fd > 256)

    {

      ASSERT (dup2 (fd, 255) == 255);

      ASSERT (dup2 (fd, 256) == 256);

      ASSERT (close (255) == 0);

      ASSERT (close (256) == 0);

    }

  ASSERT (dup2 (fd, bad_fd - 1) == bad_fd - 1);

  ASSERT (close (bad_fd - 1) == 0);

  errno = 0;

  ASSERT (dup2 (fd, bad_fd) == -1);

  ASSERT (errno == EBADF);

  /* Using dup2 can skip fds.  */

  ASSERT (dup2 (fd, fd + 2) == fd + 2);

  ASSERT (is_open (fd));

  ASSERT (!is_open (fd + 1));

  ASSERT (is_open (fd + 2));

  /* Verify that dup2 closes the previous occupant of a fd.  */

  ASSERT (open ("/dev/null", O_WRONLY, 0600) == fd + 1);

  ASSERT (dup2 (fd + 1, fd) == fd);

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

  ASSERT (write (fd, "1", 1) == 1);

  ASSERT (dup2 (fd + 2, fd) == fd);

  ASSERT (lseek (fd, 0, SEEK_END) == 0);

  ASSERT (write (fd + 2, "2", 1) == 1);

  ASSERT (lseek (fd, 0, SEEK_SET) == 0);

  ASSERT (read (fd, buffer, 1) == 1);

  ASSERT (*buffer == '2');

#if GNULIB_TEST_CLOEXEC

  /* Any new fd created by dup2 must not be cloexec.  */

  ASSERT (close (fd + 2) == 0);

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

  ASSERT (!is_inheritable (fd + 1));

  ASSERT (dup2 (fd + 1, fd + 1) == fd + 1);

  ASSERT (!is_inheritable (fd + 1));

  ASSERT (dup2 (fd + 1, fd + 2) == fd + 2);

  ASSERT (!is_inheritable (fd + 1));

  ASSERT (is_inheritable (fd + 2));

  errno = 0;

  ASSERT (dup2 (fd + 1, -1) == -1);

  ASSERT (errno == EBADF);

  ASSERT (!is_inheritable (fd + 1));

#endif

  /* On systems that distinguish between text and binary mode, dup2

     reuses the mode of the source.  */

  setmode (fd, O_BINARY);

  ASSERT (is_mode (fd, O_BINARY));

  ASSERT (dup2 (fd, fd + 1) == fd + 1);

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

  setmode (fd, O_TEXT);

  ASSERT (is_mode (fd, O_TEXT));

  ASSERT (dup2 (fd, fd + 1) == fd + 1);

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

  /* Clean up.  */

  ASSERT (close (fd + 2) == 0);

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

  ASSERT (close (fd) == 0);

  ASSERT (unlink (file) == 0);

  return 0;

}