42 lines
1.4 KiB
C
42 lines
1.4 KiB
C
/* $Header: /sys/linux-0.97/include/sys/RCS/ioctl.h,v 0.2 1992/08/03 19:56:43 root Exp root $
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*
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* sys/ioctl.h for Linux by H.H. Bergman.
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*/
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#ifndef _SYS_IOCTL_H
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#define _SYS_IOCTL_H
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/* ioctl command encoding: 32 bits total, command in lower 16 bits,
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* size of the parameter structure in the upper 14 bits.
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* Encoding size in ioctl request is useful for catching old versions
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* and to avoid overwriting user space outside the user buffer area.
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* The highest 2 bits are reserved.
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* NOTE: This limits the max blocksize to 16kB -1 !
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*/
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#define IOC_VOID 0x00000000 /* param in size field */
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#define IOC_IN 0x40000000 /* user --> kernel */
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#define IOC_OUT 0x80000000 /* kernel --> user */
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#define IOC_INOUT (IOC_IN | IOC_OUT) /* both */
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#define IOCSIZE_MASK 0x3fff0000 /* size (max 16k-1 bytes) */
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#define IOCSIZE_SHIFT 16 /* how to get the size */
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#define IOCCMD_MASK 0x0000ffff /* command code */
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#define IOCCMD_SHIFT 0
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#define _IO(c,d) (IOC_VOID | (d)<<16) | c) /* param encoded */
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/* use _IOXX(magic, subcode, arg_t) where arg_t is the type of the
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* (last) argument field in the ioctl call, if present.
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*/
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#define _IOW(c,d,t) (IOC_IN | ((sizeof(t)<<16) & IOCSIZE_MASK) | \
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(c<<8) | d)
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#define _IOR(c,d,t) (IOC_OUT | ((sizeof(t)<<16) & IOCSIZE_MASK) | \
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(c<<8) | d)
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/* WR rather than RW to avoid conflict with stdio.h */
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#define _IOWR(c,d,t) (IOC_INOUT | (sizeof(t)<<16) & IOCSIZE_MASK) | \
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(c<<8) | d)
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extern int ioctl(int, int, ...);
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#endif
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