2 * Copyright (c) 2015-2018 Dmitry V. Levin <ldv@altlinux.org>
5 * SPDX-License-Identifier: GPL-2.0-or-later
13 tail_alloc(const size_t size)
15 const size_t page_size = get_page_size();
16 const size_t len = (size + page_size - 1) & -page_size;
17 const size_t alloc_size = len + 6 * page_size;
19 void *p = mmap(NULL, alloc_size, PROT_READ | PROT_WRITE,
20 MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
22 perror_msg_and_fail("mmap(%zu)", alloc_size);
24 void *start_work = p + 3 * page_size;
25 void *tail_guard = start_work + len;
27 if (munmap(p, page_size) ||
28 munmap(p + 2 * page_size, page_size) ||
29 munmap(tail_guard, page_size) ||
30 munmap(tail_guard + 2 * page_size, page_size))
31 perror_msg_and_fail("munmap");
33 memset(start_work, 0xff, len);
34 return tail_guard - size;
38 tail_memdup(const void *p, const size_t size)
40 void *dest = tail_alloc(size);
41 memcpy(dest, p, size);