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/* Test duplicating file descriptors.
Copyright (C) 2009 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 <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* Get declarations of the Win32 API functions. */
# define WIN32_LEAN_AND_MEAN
# include <windows.h>
#endif
#define ASSERT(expr) \
do \
{ \
if (!(expr)) \
{ \
fprintf (stderr, "%s:%d: assertion failed\n", __FILE__, __LINE__); \
fflush (stderr); \
abort (); \
} \
} \
while (0)
/* Return non-zero if FD is open. */
static int
is_open (int fd)
{
#if (defined _WIN32 || defined __WIN32__) && ! defined __CYGWIN__
/* On Win32, 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
}
int
main ()
{
const char *file = "test-dup2.tmp";
char buffer[1];
int fd = open (file, O_CREAT | 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));
/* 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);
/* 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));
/* Prove 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 (write (fd + 2, "2", 1) == 1);
ASSERT (lseek (fd, SEEK_SET, 0) == 0);
ASSERT (read (fd, buffer, 1) == 1);
ASSERT (*buffer == '2');
/* Clean up. */
ASSERT (close (fd + 2) == 0);
ASSERT (close (fd) == 0);
ASSERT (unlink (file) == 0);
return 0;
}
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