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/*
* Copyright (c) 2012-2018 Zeex
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* 1. Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#include <stddef.h>
#include <unistd.h>
#include <sys/mman.h>
#include "subhook.h"
#ifdef SUBHOOK_APPLE
#include <mach/mach.h>
#endif
#define SUBHOOK_CODE_PROTECT_FLAGS (PROT_READ | PROT_WRITE | PROT_EXEC)
int subhook_unprotect(void *address, size_t size) {
long pagesize;
pagesize = sysconf(_SC_PAGESIZE);
address = (void *)((long)address & ~(pagesize - 1));
int error = mprotect(address, size, SUBHOOK_CODE_PROTECT_FLAGS);
#ifdef SUBHOOK_APPLE
if (-1 == error)
{
/* If mprotect fails, try to use VM_PROT_COPY with vm_protect. */
kern_return_t kret = vm_protect(mach_task_self(), (unsigned long)address, size, 0, SUBHOOK_CODE_PROTECT_FLAGS | VM_PROT_COPY);
if (kret != KERN_SUCCESS)
{
error = -1;
}
error = 0;
}
#endif
return error;
}
void *subhook_alloc_code(size_t size) {
void *address;
address = mmap(NULL,
size,
SUBHOOK_CODE_PROTECT_FLAGS,
#if defined MAP_32BIT && !defined __APPLE__
MAP_32BIT |
#endif
MAP_PRIVATE | MAP_ANONYMOUS,
-1,
0);
return address == MAP_FAILED ? NULL : address;
}
int subhook_free_code(void *address, size_t size) {
if (address == NULL) {
return 0;
}
return munmap(address, size);
}
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