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33 lines
1.1 KiB
C
33 lines
1.1 KiB
C
#ifndef IOCTL_H
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#define IOCTL_H
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#include <linux/ioctl.h>
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/* Structs are the way to pass multiple arguments. */
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typedef struct {
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int i;
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int j;
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} lkmc_ioctl_struct;
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/* Some random number I can't understand how to choose. */
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#define LKMC_IOCTL_MAGIC 0x33
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/*
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* I think those number does not *need* to be unique across, that is just to help debugging:
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* https://stackoverflow.com/questions/22496123/what-is-the-meaning-of-this-macro-iormy-macig-0-int
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*
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* However, the ioctl syscall highjacks several low values at do_vfs_ioctl, e.g.
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* This "forces" use to use the _IOx macros...
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* https://stackoverflow.com/questions/10071296/ioctl-is-not-called-if-cmd-2
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*
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* Some of those magic low values are used for fnctl, which can also be used on regular files:
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* e.g. FIOCLEX for close-on-exec:
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* https://stackoverflow.com/questions/6125068/what-does-the-fd-cloexec-fcntl-flag-do
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*
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* TODO are the W or R of _IOx and type functional, or only to help with uniqueness?
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* */
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#define LKMC_IOCTL_INC _IOWR(LKMC_IOCTL_MAGIC, 0, int)
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#define LKMC_IOCTL_INC_DEC _IOWR(LKMC_IOCTL_MAGIC, 1, lkmc_ioctl_struct)
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#endif
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