1*4e179ddaSchristos /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */
2*4e179ddaSchristos /*
3*4e179ddaSchristos * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
4*4e179ddaSchristos *
5*4e179ddaSchristos * Permission to use, copy, modify, and distribute this software for any
6*4e179ddaSchristos * purpose with or without fee is hereby granted, provided that the above
7*4e179ddaSchristos * copyright notice and this permission notice appear in all copies.
8*4e179ddaSchristos *
9*4e179ddaSchristos * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10*4e179ddaSchristos * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11*4e179ddaSchristos * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12*4e179ddaSchristos * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13*4e179ddaSchristos * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14*4e179ddaSchristos * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15*4e179ddaSchristos * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16*4e179ddaSchristos */
17*4e179ddaSchristos
18*4e179ddaSchristos #include <errno.h>
19*4e179ddaSchristos #include <stdlib.h>
20*4e179ddaSchristos #include <stdint.h>
21*4e179ddaSchristos #include <string.h>
22*4e179ddaSchristos #include <unistd.h>
23*4e179ddaSchristos
24*4e179ddaSchristos #include "compat.h"
25*4e179ddaSchristos
26*4e179ddaSchristos /*
27*4e179ddaSchristos * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
28*4e179ddaSchristos * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
29*4e179ddaSchristos */
30*4e179ddaSchristos #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
31*4e179ddaSchristos
32*4e179ddaSchristos void *
recallocarray(void * ptr,size_t oldnmemb,size_t newnmemb,size_t size)33*4e179ddaSchristos recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
34*4e179ddaSchristos {
35*4e179ddaSchristos size_t oldsize, newsize;
36*4e179ddaSchristos void *newptr;
37*4e179ddaSchristos
38*4e179ddaSchristos if (ptr == NULL)
39*4e179ddaSchristos return calloc(newnmemb, size);
40*4e179ddaSchristos
41*4e179ddaSchristos if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
42*4e179ddaSchristos newnmemb > 0 && SIZE_MAX / newnmemb < size) {
43*4e179ddaSchristos errno = ENOMEM;
44*4e179ddaSchristos return NULL;
45*4e179ddaSchristos }
46*4e179ddaSchristos newsize = newnmemb * size;
47*4e179ddaSchristos
48*4e179ddaSchristos if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
49*4e179ddaSchristos oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
50*4e179ddaSchristos errno = EINVAL;
51*4e179ddaSchristos return NULL;
52*4e179ddaSchristos }
53*4e179ddaSchristos oldsize = oldnmemb * size;
54*4e179ddaSchristos
55*4e179ddaSchristos /*
56*4e179ddaSchristos * Don't bother too much if we're shrinking just a bit,
57*4e179ddaSchristos * we do not shrink for series of small steps, oh well.
58*4e179ddaSchristos */
59*4e179ddaSchristos if (newsize <= oldsize) {
60*4e179ddaSchristos size_t d = oldsize - newsize;
61*4e179ddaSchristos
62*4e179ddaSchristos if (d < oldsize / 2 && d < (size_t)getpagesize()) {
63*4e179ddaSchristos memset((char *)ptr + newsize, 0, d);
64*4e179ddaSchristos return ptr;
65*4e179ddaSchristos }
66*4e179ddaSchristos }
67*4e179ddaSchristos
68*4e179ddaSchristos newptr = malloc(newsize);
69*4e179ddaSchristos if (newptr == NULL)
70*4e179ddaSchristos return NULL;
71*4e179ddaSchristos
72*4e179ddaSchristos if (newsize > oldsize) {
73*4e179ddaSchristos memcpy(newptr, ptr, oldsize);
74*4e179ddaSchristos memset((char *)newptr + oldsize, 0, newsize - oldsize);
75*4e179ddaSchristos } else
76*4e179ddaSchristos memcpy(newptr, ptr, newsize);
77*4e179ddaSchristos
78*4e179ddaSchristos explicit_bzero(ptr, oldsize);
79*4e179ddaSchristos free(ptr);
80*4e179ddaSchristos
81*4e179ddaSchristos return newptr;
82*4e179ddaSchristos }
83