1 24fb1a39 2025-06-02 kirill /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */
3 24fb1a39 2025-06-02 kirill * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
5 24fb1a39 2025-06-02 kirill * Permission to use, copy, modify, and distribute this software for any
6 24fb1a39 2025-06-02 kirill * purpose with or without fee is hereby granted, provided that the above
7 24fb1a39 2025-06-02 kirill * copyright notice and this permission notice appear in all copies.
9 24fb1a39 2025-06-02 kirill * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 24fb1a39 2025-06-02 kirill * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 24fb1a39 2025-06-02 kirill * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 24fb1a39 2025-06-02 kirill * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 24fb1a39 2025-06-02 kirill * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 24fb1a39 2025-06-02 kirill * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 24fb1a39 2025-06-02 kirill * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 24fb1a39 2025-06-02 kirill /* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */
20 24fb1a39 2025-06-02 kirill #include <errno.h>
21 24fb1a39 2025-06-02 kirill #include <stdlib.h>
22 24fb1a39 2025-06-02 kirill #include <stdint.h>
23 24fb1a39 2025-06-02 kirill #include <string.h>
24 24fb1a39 2025-06-02 kirill #include <unistd.h>
26 24fb1a39 2025-06-02 kirill #include "openbsd-compat.h"
29 24fb1a39 2025-06-02 kirill * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
30 24fb1a39 2025-06-02 kirill * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
32 24fb1a39 2025-06-02 kirill #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
35 24fb1a39 2025-06-02 kirill recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
37 24fb1a39 2025-06-02 kirill size_t oldsize, newsize;
38 24fb1a39 2025-06-02 kirill void *newptr;
40 24fb1a39 2025-06-02 kirill if (ptr == NULL)
41 24fb1a39 2025-06-02 kirill return calloc(newnmemb, size);
43 24fb1a39 2025-06-02 kirill if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
44 24fb1a39 2025-06-02 kirill newnmemb > 0 && SIZE_MAX / newnmemb < size) {
45 24fb1a39 2025-06-02 kirill errno = ENOMEM;
46 24fb1a39 2025-06-02 kirill return NULL;
48 24fb1a39 2025-06-02 kirill newsize = newnmemb * size;
50 24fb1a39 2025-06-02 kirill if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
51 24fb1a39 2025-06-02 kirill oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
52 24fb1a39 2025-06-02 kirill errno = EINVAL;
53 24fb1a39 2025-06-02 kirill return NULL;
55 24fb1a39 2025-06-02 kirill oldsize = oldnmemb * size;
58 24fb1a39 2025-06-02 kirill * Don't bother too much if we're shrinking just a bit,
59 24fb1a39 2025-06-02 kirill * we do not shrink for series of small steps, oh well.
61 24fb1a39 2025-06-02 kirill if (newsize <= oldsize) {
62 24fb1a39 2025-06-02 kirill size_t d = oldsize - newsize;
64 24fb1a39 2025-06-02 kirill if (d < oldsize / 2 && d < (size_t)getpagesize()) {
65 24fb1a39 2025-06-02 kirill memset((char *)ptr + newsize, 0, d);
66 24fb1a39 2025-06-02 kirill return ptr;
70 24fb1a39 2025-06-02 kirill newptr = malloc(newsize);
71 24fb1a39 2025-06-02 kirill if (newptr == NULL)
72 24fb1a39 2025-06-02 kirill return NULL;
74 24fb1a39 2025-06-02 kirill if (newsize > oldsize) {
75 24fb1a39 2025-06-02 kirill memcpy(newptr, ptr, oldsize);
76 24fb1a39 2025-06-02 kirill memset((char *)newptr + oldsize, 0, newsize - oldsize);
78 24fb1a39 2025-06-02 kirill memcpy(newptr, ptr, newsize);
80 24fb1a39 2025-06-02 kirill explicit_bzero(ptr, oldsize);
81 24fb1a39 2025-06-02 kirill free(ptr);
83 24fb1a39 2025-06-02 kirill return newptr;
