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// REQUIRES: native-run
// RUN: %clang_builtins %s %librt -o %t && %run %t
//===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===//
//
// The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#if defined(_WIN32)
#include <windows.h>
void __clear_cache(void* start, void* end)
{
if (!FlushInstructionCache(GetCurrentProcess(), start, end-start))
exit(1);
}
void __enable_execute_stack(void *addr)
{
MEMORY_BASIC_INFORMATION b;
if (!VirtualQuery(addr, &b, sizeof(b)))
exit(1);
if (!VirtualProtect(b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE, &b.Protect))
exit(1);
}
#else
#include <sys/mman.h>
extern void __clear_cache(void* start, void* end);
extern void __enable_execute_stack(void* addr);
#endif
typedef int (*pfunc)(void);
int func1()
{
return 1;
}
int func2()
{
return 2;
}
void *__attribute__((noinline))
memcpy_f(void *dst, const void *src, size_t n) {
// ARM and MIPS nartually align functions, but use the LSB for ISA selection
// (THUMB, MIPS16/uMIPS respectively). Ensure that the ISA bit is ignored in
// the memcpy
#if defined(__arm__) || defined(__mips__)
return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) |
((uintptr_t)src & 1));
#else
return memcpy(dst, (void *)((uintptr_t)src), n);
#endif
}
int main()
{
unsigned char execution_buffer[128];
// mark stack page containing execution_buffer to be executable
__enable_execute_stack(execution_buffer);
// verify you can copy and execute a function
pfunc f1 = (pfunc)memcpy_f(execution_buffer, func1, 128);
__clear_cache(execution_buffer, &execution_buffer[128]);
if ((*f1)() != 1)
return 1;
// verify you can overwrite a function with another
pfunc f2 = (pfunc)memcpy_f(execution_buffer, func2, 128);
__clear_cache(execution_buffer, &execution_buffer[128]);
if ((*f2)() != 2)
return 1;
return 0;
}
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