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/* Test that dup_safer leaves standard fds alone.
Copyright (C) 2009-2024 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 <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 set_binary_mode my_set_binary_mode
static int
set_binary_mode (_GL_UNUSED int fd, _GL_UNUSED int mode)
{
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 = set_binary_mode (fd, O_BINARY);
set_binary_mode (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. */
set_binary_mode (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);
set_binary_mode (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 test_exit_status;
}
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