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/*
* Copyright © 2021 Michael Smith <mikesmiffy128@gmail.com>
*
* Permission to use, copy, modify, and/or distribute this software for any
* purpose with or without fee is hereby granted, provided that the above
* copyright notice and this permission notice appear in all copies.
*
* THE SOFTWARE IS PROVIDED “AS IS” AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH
* REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT,
* INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
* LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR
* OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
* PERFORMANCE OF THIS SOFTWARE.
*/
#ifndef INC_HOOK_H
#define INC_HOOK_H
#include "intdefs.h"
/*
* Replaces a vtable entry with a target function and returns the original
* function.
*/
static inline void *hook_vtable(void **vtable, usize off, void *target) {
void *orig = vtable[off];
vtable[off] = target;
return orig;
}
/*
* Puts an original function back after hooking.
*/
static inline void unhook_vtable(void **vtable, usize off, void *orig) {
vtable[off] = orig;
}
/*
* Returns a trampoline pointer, or null if hooking failed. Unlike hook_vtable,
* handles memory protection for you.
*/
void *hook_inline(void *func, void *target);
/*
* Reverts the function to its original unhooked state. Takes the pointer to the
* callable "original" function, i.e. the trampoline, NOT the initial function
* pointer from before hooking.
*/
void unhook_inline(void *orig);
#endif
// vi: sw=4 ts=4 noet tw=80 cc=80
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