nuttx/libs/libc/misc/lib_ioctl.c

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/****************************************************************************
* libs/libc/misc/lib_ioctl.c
*
* Copyright (C) 2014 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
* 3. Neither the name NuttX nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/ioctl.h>
#include <stdarg.h>
#include <errno.h>
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#include <assert.h>
#include <nuttx/fs/fs.h>
#include "libc.h"
#if defined(CONFIG_LIBC_IOCTL_VARIADIC) && CONFIG_NFILE_DESCRIPTORS > 0
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ioctl
*
* Description:
* Perform device specific operations.
*
* Input Parameters:
* fd File/socket descriptor of device
* req The ioctl command
* ... A third argument of type unsigned long is expected
*
* Returned Value:
* >=0 on success (positive non-zero values are cmd-specific)
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* -1 on failure with errno set properly:
*
* EBADF
* 'fd' is not a valid descriptor.
* EFAULT
* 'arg' references an inaccessible memory area.
* EINVAL
* 'cmd' or 'arg' is not valid.
* ENOTTY
* 'fd' is not associated with a character special device.
* ENOTTY
* The specified request does not apply to the kind of object that the
* descriptor 'fd' references.
*
****************************************************************************/
int ioctl(int fd, int req, ...)
{
unsigned long arg;
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va_list ap;
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/* Get the unsigned long argument.
*
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* REVISIT: This could be the cause of the crash down the road if the
* actual size of the argument is anything other than sizeof(unsigned long).
* Most small integers will be promoted to 'int'. ARM should pass the
* following test with all three types having sizeof(type) == 4 bytes.
* 'float' should also be tested. But 'long long' and 'double' are out of
* the question! Don't try to pass them.
*
* And what will happen if no third argument is passed? In most cases,
* this should just result in a garbage value for arg. But you may
* discover cases where something worse happens!
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*/
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DEBUGASSERT(sizeof(int) == sizeof(unsigned long) &&
sizeof(FAR void *) == sizeof(unsigned long));
va_start(ap, req);
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arg = va_arg(ap, unsigned long);
va_end(ap);
/* Then let fs_ioctl() to the real work */
return fs_ioctl(fd, req, arg);
}
#endif /* CONFIG_LIBC_IOCTL_VARIADIC && CONFIG_NFILE_DESCRIPTORS > 0 */