ioctl.h 3.4 KB

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  1. /* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
  2. #ifndef _UAPI_ASM_GENERIC_IOCTL_H
  3. #define _UAPI_ASM_GENERIC_IOCTL_H
  4. /* ioctl command encoding: 32 bits total, command in lower 16 bits,
  5. * size of the parameter structure in the lower 14 bits of the
  6. * upper 16 bits.
  7. * Encoding the size of the parameter structure in the ioctl request
  8. * is useful for catching programs compiled with old versions
  9. * and to avoid overwriting user space outside the user buffer area.
  10. * The highest 2 bits are reserved for indicating the ``access mode''.
  11. * NOTE: This limits the max parameter size to 16kB -1 !
  12. */
  13. /*
  14. * The following is for compatibility across the various Linux
  15. * platforms. The generic ioctl numbering scheme doesn't really enforce
  16. * a type field. De facto, however, the top 8 bits of the lower 16
  17. * bits are indeed used as a type field, so we might just as well make
  18. * this explicit here. Please be sure to use the decoding macros
  19. * below from now on.
  20. */
  21. #define _IOC_NRBITS 8
  22. #define _IOC_TYPEBITS 8
  23. /*
  24. * Let any architecture override either of the following before
  25. * including this file.
  26. */
  27. #ifndef _IOC_SIZEBITS
  28. # define _IOC_SIZEBITS 14
  29. #endif
  30. #ifndef _IOC_DIRBITS
  31. # define _IOC_DIRBITS 2
  32. #endif
  33. #define _IOC_NRMASK ((1 << _IOC_NRBITS)-1)
  34. #define _IOC_TYPEMASK ((1 << _IOC_TYPEBITS)-1)
  35. #define _IOC_SIZEMASK ((1 << _IOC_SIZEBITS)-1)
  36. #define _IOC_DIRMASK ((1 << _IOC_DIRBITS)-1)
  37. #define _IOC_NRSHIFT 0
  38. #define _IOC_TYPESHIFT (_IOC_NRSHIFT+_IOC_NRBITS)
  39. #define _IOC_SIZESHIFT (_IOC_TYPESHIFT+_IOC_TYPEBITS)
  40. #define _IOC_DIRSHIFT (_IOC_SIZESHIFT+_IOC_SIZEBITS)
  41. /*
  42. * Direction bits, which any architecture can choose to override
  43. * before including this file.
  44. *
  45. * NOTE: _IOC_WRITE means userland is writing and kernel is
  46. * reading. _IOC_READ means userland is reading and kernel is writing.
  47. */
  48. #ifndef _IOC_NONE
  49. # define _IOC_NONE 0U
  50. #endif
  51. #ifndef _IOC_WRITE
  52. # define _IOC_WRITE 1U
  53. #endif
  54. #ifndef _IOC_READ
  55. # define _IOC_READ 2U
  56. #endif
  57. #define _IOC(dir,type,nr,size) \
  58. (((dir) << _IOC_DIRSHIFT) | \
  59. ((type) << _IOC_TYPESHIFT) | \
  60. ((nr) << _IOC_NRSHIFT) | \
  61. ((size) << _IOC_SIZESHIFT))
  62. #ifndef __KERNEL__
  63. #define _IOC_TYPECHECK(t) (sizeof(t))
  64. #endif
  65. /*
  66. * Used to create numbers.
  67. *
  68. * NOTE: _IOW means userland is writing and kernel is reading. _IOR
  69. * means userland is reading and kernel is writing.
  70. */
  71. #define _IO(type,nr) _IOC(_IOC_NONE,(type),(nr),0)
  72. #define _IOR(type,nr,size) _IOC(_IOC_READ,(type),(nr),(_IOC_TYPECHECK(size)))
  73. #define _IOW(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  74. #define _IOWR(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),(_IOC_TYPECHECK(size)))
  75. #define _IOR_BAD(type,nr,size) _IOC(_IOC_READ,(type),(nr),sizeof(size))
  76. #define _IOW_BAD(type,nr,size) _IOC(_IOC_WRITE,(type),(nr),sizeof(size))
  77. #define _IOWR_BAD(type,nr,size) _IOC(_IOC_READ|_IOC_WRITE,(type),(nr),sizeof(size))
  78. /* used to decode ioctl numbers.. */
  79. #define _IOC_DIR(nr) (((nr) >> _IOC_DIRSHIFT) & _IOC_DIRMASK)
  80. #define _IOC_TYPE(nr) (((nr) >> _IOC_TYPESHIFT) & _IOC_TYPEMASK)
  81. #define _IOC_NR(nr) (((nr) >> _IOC_NRSHIFT) & _IOC_NRMASK)
  82. #define _IOC_SIZE(nr) (((nr) >> _IOC_SIZESHIFT) & _IOC_SIZEMASK)
  83. /* ...and for the drivers/sound files... */
  84. #define IOC_IN (_IOC_WRITE << _IOC_DIRSHIFT)
  85. #define IOC_OUT (_IOC_READ << _IOC_DIRSHIFT)
  86. #define IOC_INOUT ((_IOC_WRITE|_IOC_READ) << _IOC_DIRSHIFT)
  87. #define IOCSIZE_MASK (_IOC_SIZEMASK << _IOC_SIZESHIFT)
  88. #define IOCSIZE_SHIFT (_IOC_SIZESHIFT)
  89. #endif /* _UAPI_ASM_GENERIC_IOCTL_H */