ulinux/ioctl.h

   1 #ifndef ULINUX_IOCTL_H
   2 #define ULINUX_IOCTL_H
   3 /*
   4  * this code is protected by the GNU affero GPLv3
   5  * author:Sylvain BERTRAND
   6  */
   7
   8 /*
   9  * ioctl command encoding: 32 bits total, command in lower 16 bits,
  10  * size of the parameter structure in the lower 14 bits of the
  11  * upper 16 bits.
  12  * Encoding the size of the parameter structure in the ioctl request
  13  * is useful for catching programs compiled with old versions
  14  * and to avoid overwriting user space outside the user buffer area.
  15  * The highest 2 bits are reserved for indicating the ``access mode''.
  16  * NOTE: This limits the max parameter size to 16kB -1 !
  17  *
  18  * The following is for compatibility across the various Linux
  19  * platforms.  The generic ioctl numbering scheme doesn't really enforce
  20  * a type field.  De facto, however, the top 8 bits of the lower 16
  21  * bits are indeed used as a type field, so we might just as well make
  22  * this explicit here.  Please be sure to use the decoding macros
  23  * below from now on.
  24  */
  25
  26 #define ULINUX_IOC_NRBITS   8
  27 #define ULINUX_IOC_TYPEBITS 8
  28
  29 /*
  30  * Let any architecture override either of the following before
  31  * including this file.
  32  */
  33
  34 /*XXX:can be arch dependent*/
  35 #define ULINUX_IOC_SIZEBITS 14
  36
  37 /*XXX:can be arch dependent*/
  38 #define ULINUX_IOC_DIRBITS 2
  39
  40 #define ULINUX_IOC_NRMASK   ((1<<ULINUX_IOC_NRBITS)-1)
  41 #define ULINUX_IOC_TYPEMASK ((1<<ULINUX_IOC_TYPEBITS)-1)
  42 #define ULINUX_IOC_SIZEMASK     ((1<<ULINUX_IOC_SIZEBITS)-1)
  43 #define ULINUX_IOC_DIRMASK      ((1<<ULINUX_IOC_DIRBITS)-1)
  44
  45 #define ULINUX_IOC_NRSHIFT   0
  46 #define ULINUX_IOC_TYPESHIFT (ULINUX_IOC_NRSHIFT+ULINUX_IOC_NRBITS)
  47 #define ULINUX_IOC_SIZESHIFT (ULINUX_IOC_TYPESHIFT+ULINUX_IOC_TYPEBITS)
  48 #define ULINUX_IOC_DIRSHIFT  (ULINUX_IOC_SIZESHIFT+ULINUX_IOC_SIZEBITS)
  49
  50 /*
  51  * Direction bits, which any architecture can choose to override
  52  * before including this file.
  53  */
  54
  55 /*XXX:can be arch dependent*/
  56 #define ULINUX_IOC_NONE 0U
  57
  58 /*XXX:can be arch dependent*/
  59 #define ULINUX_IOC_WRITE 1U
  60
  61 /*XXX:can be arch dependent*/
  62 #define ULINUX_IOC_READ 2U
  63
  64 #define ULINUX_IOC(dir,type,nr,size) \
  65  (((dir)<<ULINUX_IOC_DIRSHIFT) | \
  66  ((type)<<ULINUX_IOC_TYPESHIFT) | \
  67  ((nr)<<ULINUX_IOC_NRSHIFT) | \
  68  ((size)<<ULINUX_IOC_SIZESHIFT))
  69
  70 #define ULINUX_IOC_TYPECHECK(t) (sizeof(t))
  71
  72 /*used to create numbers*/
  73 #define ULINUX_IO(type,nr) ULINUX_IOC(ULINUX_IOC_NONE,(type),(nr),0)
  74 #define ULINUX_IOR(type,nr,size)\
  75  ULINUX_IOC(ULINUX_IOC_READ,(type),(nr),(ULINUX_IOC_TYPECHECK(size)))
  76 #define ULINUX_IOW(type,nr,size)\
  77  ULINUX_IOC(ULINUX_IOC_WRITE,(type),(nr),(ULINUX_IOC_TYPECHECK(size)))
  78 #define ULINUX_IOWR(type,nr,size)\
  79  ULINUX_IOC(ULINUX_IOC_READ|ULINUX_IOC_WRITE,(type),(nr),\
  80 (ULINUX_IOC_TYPECHECK(size)))
  81 #define ULINUX_IOR_BAD(type,nr,size) ULINUX_IOC(ULINUX_IOC_READ,(type),(nr),\
  82 sizeof(size))
  83 #define ULINUX_IOW_BAD(type,nr,size) ULINUX_IOC(ULINUX_IOC_WRITE,(type),(nr),\
  84 sizeof(size))
  85 #define ULINUX_IOWR_BAD(type,nr,size)\
  86  ULINUX_IOC(ULINUX_IOC_READ|ULINUX_IOC_WRITE,(type),(nr),sizeof(size))
  87
  88 /*used to decode ioctl numbers*/
  89 #define ULINUX_IOC_DIR(nr) (((nr)>>ULINUX_IOC_DIRSHIFT)&ULINUX_IOC_DIRMASK)
  90 #define ULINUX_IOC_TYPE(nr) (((nr)>>ULINUX_IOC_TYPESHIFT)&ULINUX_IOC_TYPEMASK)
  91 #define ULINUX_IOC_NR(nr) (((nr)>>ULINUX_IOC_NRSHIFT)&ULINUX_IOC_NRMASK)
  92 #define ULINUX_IOC_SIZE(nr) (((nr)>>ULINUX_IOC_SIZESHIFT)&ULINUX_IOC_SIZEMASK)
  93
  94 /*...and for the drivers/sound files...*/
  95 #define ULINUX_IOC_IN (ULINUX_IOC_WRITE<<ULINUX_IOC_DIRSHIFT)
  96 #define ULINUX_IOC_OUT (ULINUX_IOC_READ<<ULINUX_IOC_DIRSHIFT)
  97 #define ULINUX_IOC_INOUT ((ULINUX_IOC_WRITE|ULINUX_IOC_READ)<<\
  98 ULINUX_IOC_DIRSHIFT)
  99 #define ULINUX_IOCSIZE_MASK (ULINUX_IOC_SIZEMASK<<ULINUX_IOC_SIZESHIFT)
 100 #define ULINUX_IOCSIZE_SHIFT (ULINUX_IOC_SIZESHIFT)
 101 #endif