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/* Test duplicating file descriptors.
Copyright (C) 2009-2023 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 "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 __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"
/* Tell GCC not to warn about the specific edge cases tested here. */
#if __GNUC__ >= 13
# pragma GCC diagnostic ignored "-Wanalyzer-fd-leak"
# pragma GCC diagnostic ignored "-Wanalyzer-fd-use-without-check"
#endif
/* Return non-zero if FD is open. */
static int
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
}
#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 __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 set_binary_mode(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 = set_binary_mode (fd, O_BINARY);
set_binary_mode (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. */
set_binary_mode (fd, O_BINARY);
ASSERT (is_mode (fd, O_BINARY));
ASSERT (dup2 (fd, fd + 1) == fd + 1);
ASSERT (is_mode (fd + 1, O_BINARY));
set_binary_mode (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;
}
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