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- #ifndef _ASM_GENERIC_IOCTL_H
- #define _ASM_GENERIC_IOCTL_H
- /* ioctl command encoding: 32 bits total, command in lower 16 bits,
- * size of the parameter structure in the lower 14 bits of the
- * upper 16 bits.
- * Encoding the size of the parameter structure in the ioctl request
- * is useful for catching programs compiled with old versions
- * and to avoid overwriting user space outside the user buffer area.
- * The highest 2 bits are reserved for indicating the ``access mode''.
- * NOTE: This limits the max parameter size to 16kB -1 !
- */
- /*
- * 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
- /*
- * Let any architecture override either of the following before
- * including this file.
- */
- #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.
- */
- #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))
- #define _IOC_TYPECHECK(t) (sizeof(t))
- /* used to create numbers */
- #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)))
- #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
- #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
- #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
- /* used to decode ioctl numbers.. */
- #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
- #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
- #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
- #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
- /* ...and for the drivers/sound files... */
- #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
- #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
- #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
- #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
- #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
- #endif /* _ASM_GENERIC_IOCTL_H */
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