FreeBSD/Linux Kernel Cross Reference
sys/sys/ioccom.h

     /*      $NetBSD: ioccom.h,v 1.13 2019/05/26 10:21:33 hannken Exp $      */
     
     /*-
      * Copyright (c) 1982, 1986, 1990, 1993, 1994
      *      The Regents of the University of California.  All rights reserved.
      *
      * 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 of the University 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 REGENTS 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 REGENTS 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.
     *
     *      @(#)ioccom.h    8.3 (Berkeley) 1/9/95
     */
    
    #ifndef _SYS_IOCCOM_H_
    #define _SYS_IOCCOM_H_
    
    /*
     * Ioctl's have the command encoded in the lower word, and the size of
     * any in or out parameters in the upper word.  The high 3 bits of the
     * upper word are used to encode the in/out status of the parameter.
     *
     *       31 29 28                     16 15            8 7             0
     *      +---------------------------------------------------------------+
     *      | I/O | Parameter Length        | Command Group | Command       |
     *      +---------------------------------------------------------------+
     */
    #define IOCPARM_MASK    0x1fff          /* parameter length, at most 13 bits */
    #define IOCPARM_SHIFT   16
    #define IOCGROUP_SHIFT  8
    #define IOCPARM_LEN(x)  (((x) >> IOCPARM_SHIFT) & IOCPARM_MASK)
    #define IOCBASECMD(x)   ((x) & ~(IOCPARM_MASK << IOCPARM_SHIFT))
    #define IOCGROUP(x)     (((x) >> IOCGROUP_SHIFT) & 0xff)
    
    #define IOCPARM_MAX     NBPG    /* max size of ioctl args, mult. of NBPG */
                                    /* no parameters */
    #define IOC_VOID        (unsigned long)0x20000000
                                    /* copy parameters out */
    #define IOC_OUT         (unsigned long)0x40000000
                                    /* copy parameters in */
    #define IOC_IN          (unsigned long)0x80000000
                                    /* copy parameters in and out */
    #define IOC_INOUT       (IOC_IN|IOC_OUT)
                                    /* mask for IN/OUT/VOID */
    #define IOC_DIRMASK     (unsigned long)0xe0000000
    
    #define _IOC(inout, group, num, len) \
        ((inout) | (((len) & IOCPARM_MASK) << IOCPARM_SHIFT) | \
        ((group) << IOCGROUP_SHIFT) | (num))
    #define _IO(g,n)        _IOC(IOC_VOID,  (g), (n), 0)
    #define _IOR(g,n,t)     _IOC(IOC_OUT,   (g), (n), sizeof(t))
    #define _IOW(g,n,t)     _IOC(IOC_IN,    (g), (n), sizeof(t))
    /* this should be _IORW, but stdio got there first */
    #define _IOWR(g,n,t)    _IOC(IOC_INOUT, (g), (n), sizeof(t))
    
    #define IOCSNPRINTF(buf, len, cmd) \
        snprintf((buf), (len), "_IO%s%s('%c', %hhu)", \
            (((cmd) >> 30) & 1) ? "R" : "", \
            (((cmd) >> 30) & 2) ? "W" : "", \
            (char)IOCGROUP(cmd), (unsigned char)(cmd))
                    
    
    #endif /* !_SYS_IOCCOM_H_ */

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