1 /* Test if a memory region is wholly unwritable. Mach version.
2 Copyright (C) 2004-2022 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <https://www.gnu.org/licenses/>. */
18
19 #include <stdlib.h>
20 #include <stdint.h>
21 #include <mach.h>
22
23 /* Return 1 if the whole area PTR .. PTR+SIZE is not writable.
24 Return -1 if it is writable. */
25
26 int
__readonly_area(const char * ptr,size_t size)27 __readonly_area (const char *ptr, size_t size)
28 {
29 vm_address_t region_address = (uintptr_t) ptr;
30 vm_size_t region_length = size;
31 vm_prot_t protection;
32 vm_prot_t max_protection;
33 vm_inherit_t inheritance;
34 boolean_t is_shared;
35 mach_port_t object_name;
36 vm_offset_t offset;
37
38 while (__vm_region (__mach_task_self (),
39 ®ion_address, ®ion_length,
40 &protection, &max_protection, &inheritance, &is_shared,
41 &object_name, &offset) == KERN_SUCCESS
42 && region_address <= (uintptr_t) ptr)
43 {
44 region_address += region_length;
45 if (region_address < (uintptr_t) ptr)
46 continue;
47
48 if (protection & VM_PROT_WRITE)
49 return -1;
50
51 if (region_address - (uintptr_t) ptr >= size)
52 break;
53 }
54
55 return 1;
56 }
57