1 // REQUIRES: native-run
2 // RUN: %clang_builtins %s %librt -o %t && %run %t
3 //===-- enable_execute_stack_test.c - Test __enable_execute_stack ----------===//
4 //
5 //                     The LLVM Compiler Infrastructure
6 //
7 // This file is dual licensed under the MIT and the University of Illinois Open
8 // Source Licenses. See LICENSE.TXT for details.
9 //
10 //===----------------------------------------------------------------------===//
11 
12 
13 #include <stdio.h>
14 #include <string.h>
15 #include <stdint.h>
16 #if defined(_WIN32)
17 #include <windows.h>
18 void __clear_cache(void* start, void* end)
19 {
20     if (!FlushInstructionCache(GetCurrentProcess(), start, end-start))
21         exit(1);
22 }
23 void __enable_execute_stack(void *addr)
24 {
25     MEMORY_BASIC_INFORMATION b;
26 
27     if (!VirtualQuery(addr, &b, sizeof(b)))
28         exit(1);
29     if (!VirtualProtect(b.BaseAddress, b.RegionSize, PAGE_EXECUTE_READWRITE, &b.Protect))
30         exit(1);
31 }
32 #else
33 #include <sys/mman.h>
34 extern void __clear_cache(void* start, void* end);
35 extern void __enable_execute_stack(void* addr);
36 #endif
37 
38 typedef int (*pfunc)(void);
39 
40 int func1()
41 {
42     return 1;
43 }
44 
45 int func2()
46 {
47     return 2;
48 }
49 
50 void *__attribute__((noinline))
51 memcpy_f(void *dst, const void *src, size_t n) {
52 // ARM and MIPS nartually align functions, but use the LSB for ISA selection
53 // (THUMB, MIPS16/uMIPS respectively).  Ensure that the ISA bit is ignored in
54 // the memcpy
55 #if defined(__arm__) || defined(__mips__)
56   return (void *)((uintptr_t)memcpy(dst, (void *)((uintptr_t)src & ~1), n) |
57                   ((uintptr_t)src & 1));
58 #else
59   return memcpy(dst, (void *)((uintptr_t)src), n);
60 #endif
61 }
62 
63 int main()
64 {
65     unsigned char execution_buffer[128];
66     // mark stack page containing execution_buffer to be executable
67     __enable_execute_stack(execution_buffer);
68 
69     // verify you can copy and execute a function
70     pfunc f1 = (pfunc)memcpy_f(execution_buffer, func1, 128);
71     __clear_cache(execution_buffer, &execution_buffer[128]);
72     if ((*f1)() != 1)
73         return 1;
74 
75     // verify you can overwrite a function with another
76     pfunc f2 = (pfunc)memcpy_f(execution_buffer, func2, 128);
77     __clear_cache(execution_buffer, &execution_buffer[128]);
78     if ((*f2)() != 2)
79         return 1;
80 
81     return 0;
82 }
83