1 e9e18b5e 2022-03-19 op /* $OpenBSD: recallocarray.c,v 1.2 2021/03/18 11:16:58 claudio Exp $ */
3 8f01fac2 2021-03-12 op * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
5 8f01fac2 2021-03-12 op * Permission to use, copy, modify, and distribute this software for any
6 8f01fac2 2021-03-12 op * purpose with or without fee is hereby granted, provided that the above
7 8f01fac2 2021-03-12 op * copyright notice and this permission notice appear in all copies.
9 8f01fac2 2021-03-12 op * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 8f01fac2 2021-03-12 op * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 8f01fac2 2021-03-12 op * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 8f01fac2 2021-03-12 op * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 8f01fac2 2021-03-12 op * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 8f01fac2 2021-03-12 op * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 8f01fac2 2021-03-12 op * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
18 8f01fac2 2021-03-12 op #include "compat.h"
20 8f01fac2 2021-03-12 op #include <errno.h>
21 8f01fac2 2021-03-12 op #include <stdlib.h>
22 8f01fac2 2021-03-12 op #include <stdint.h>
23 8f01fac2 2021-03-12 op #include <string.h>
24 8f01fac2 2021-03-12 op #include <unistd.h>
27 8f01fac2 2021-03-12 op * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
28 8f01fac2 2021-03-12 op * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
30 8f01fac2 2021-03-12 op #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
33 8f01fac2 2021-03-12 op * Even though specified in POSIX, the PAGESIZE and PAGE_SIZE
34 8f01fac2 2021-03-12 op * macros have very poor portability. Since we only use this
35 8f01fac2 2021-03-12 op * to avoid free() overhead for small shrinking, simply pick
36 8f01fac2 2021-03-12 op * an arbitrary number.
38 8f01fac2 2021-03-12 op #define getpagesize() (1UL << 12)
41 8f01fac2 2021-03-12 op recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
43 8f01fac2 2021-03-12 op size_t oldsize, newsize;
46 8f01fac2 2021-03-12 op if (ptr == NULL)
47 8f01fac2 2021-03-12 op return calloc(newnmemb, size);
49 8f01fac2 2021-03-12 op if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
50 8f01fac2 2021-03-12 op newnmemb > 0 && SIZE_MAX / newnmemb < size) {
51 8f01fac2 2021-03-12 op errno = ENOMEM;
54 8f01fac2 2021-03-12 op newsize = newnmemb * size;
56 8f01fac2 2021-03-12 op if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
57 8f01fac2 2021-03-12 op oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
58 8f01fac2 2021-03-12 op errno = EINVAL;
61 8f01fac2 2021-03-12 op oldsize = oldnmemb * size;
64 8f01fac2 2021-03-12 op * Don't bother too much if we're shrinking just a bit,
65 8f01fac2 2021-03-12 op * we do not shrink for series of small steps, oh well.
67 8f01fac2 2021-03-12 op if (newsize <= oldsize) {
68 8f01fac2 2021-03-12 op size_t d = oldsize - newsize;
70 e9e18b5e 2022-03-19 op if (d < oldsize / 2 && d < (size_t)getpagesize()) {
71 8f01fac2 2021-03-12 op memset((char *)ptr + newsize, 0, d);
76 8f01fac2 2021-03-12 op newptr = malloc(newsize);
77 8f01fac2 2021-03-12 op if (newptr == NULL)
80 8f01fac2 2021-03-12 op if (newsize > oldsize) {
81 8f01fac2 2021-03-12 op memcpy(newptr, ptr, oldsize);
82 8f01fac2 2021-03-12 op memset((char *)newptr + oldsize, 0, newsize - oldsize);
84 8f01fac2 2021-03-12 op memcpy(newptr, ptr, newsize);
86 8f01fac2 2021-03-12 op explicit_bzero(ptr, oldsize);
89 8f01fac2 2021-03-12 op return newptr;