ioctl.h

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/*
 * This file is part of the µOS++ project (https://micro-os-plus.github.io/).
 * Copyright (c) 2018-2025 Liviu Ionescu. All rights reserved.
 *
 * Permission to use, copy, modify, and/or distribute this software
 * for any purpose is hereby granted, under the terms of the MIT license.
 *
 * If a copy of the license was not distributed with this file, it can
 * be obtained from https://opensource.org/licenses/mit.
 */
 
#ifndef POSIX_SYS_IOCTL_H_
#define POSIX_SYS_IOCTL_H_
 
// ----------------------------------------------------------------------------
 
// Avoid warnings for _IOC* definitions.
#pragma GCC system_header
 
/*
 * From:
 * https://github.com/torvalds/linux/blob/master/include/uapi/asm-generic/ioctl.h
 *
 * The following is for compatibility across the various Linux
 * platforms.  The generic ioctl numbering scheme doesn't really enforce
 * a type field.  De facto, however, the top 8 bits of the lower 16
 * bits are indeed used as a type field, so we might just as well make
 * this explicit here.  Please be sure to use the decoding macros
 * below from now on.
 */
#define _IOC_NRBITS 8
#define _IOC_TYPEBITS 8
 
#ifndef _IOC_SIZEBITS
#define _IOC_SIZEBITS 14
#endif
 
#ifndef _IOC_DIRBITS
#define _IOC_DIRBITS 2
#endif
 
#define _IOC_NRMASK ((1 << _IOC_NRBITS) - 1)
#define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS) - 1)
#define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS) - 1)
#define _IOC_DIRMASK ((1 << _IOC_DIRBITS) - 1)
 
#define _IOC_NRSHIFT 0
#define _IOC_TYPESHIFT (_IOC_NRSHIFT + _IOC_NRBITS)
#define _IOC_SIZESHIFT (_IOC_TYPESHIFT + _IOC_TYPEBITS)
#define _IOC_DIRSHIFT (_IOC_SIZESHIFT + _IOC_SIZEBITS)
 
/*
 * Direction bits, which any architecture can choose to override
 * before including this file.
 *
 * NOTE: _IOC_WRITE means userland is writing and kernel is
 * reading. _IOC_READ means userland is reading and kernel is writing.
 */
 
#ifndef _IOC_NONE
#define _IOC_NONE 0U
#endif
 
#ifndef _IOC_WRITE
#define _IOC_WRITE 1U
#endif
 
#ifndef _IOC_READ
#define _IOC_READ 2U
#endif
 
#define _IOC(dir, type, nr, size) \
  (((dir) << _IOC_DIRSHIFT) | ((type) << _IOC_TYPESHIFT) \
   | ((nr) << _IOC_NRSHIFT) | ((size) << _IOC_SIZESHIFT))
 
#ifndef __KERNEL__
#define _IOC_TYPECHECK(t) (sizeof (t))
#endif
 
// ----------------------------------------------------------------------------
 
/*
 * From: https://github.com/torvalds/linux/blob/master/include/uapi/linux/fs.h
 *
 * Used to create numbers.
 *
 * NOTE: _IOW means userland is writing and kernel is reading. _IOR
 * means userland is reading and kernel is writing.
 */
#define _IO(type, nr) _IOC (_IOC_NONE, (type), (nr), 0)
#define _IOR(type, nr, size) \
  _IOC (_IOC_READ, (type), (nr), (_IOC_TYPECHECK (size)))
#define _IOW(type, nr, size) \
  _IOC (_IOC_WRITE, (type), (nr), (_IOC_TYPECHECK (size)))
#define _IOWR(type, nr, size) \
  _IOC (_IOC_READ | _IOC_WRITE, (type), (nr), (_IOC_TYPECHECK (size)))
 
/* 108-111 have been used for various private purposes. */
 
#define BLKSSZGET _IO (0x12, 104) /* get block logical device sector size */
#define BLKGETSIZE64 \
  _IOR (0x12, 114, size_t) /* get device size in bytes (u64 *arg) */
#define BLKPBSZGET _IO (0x12, 123) /* get block physical device sector size \
                                    */
 
// ----------------------------------------------------------------------------
 
#endif /* POSIX_SYS_IOCTL_H_ */