1*ba9bdd8bSchristos /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */
2*ba9bdd8bSchristos /*
3*ba9bdd8bSchristos * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
4*ba9bdd8bSchristos *
5*ba9bdd8bSchristos * Permission to use, copy, modify, and distribute this software for any
6*ba9bdd8bSchristos * purpose with or without fee is hereby granted, provided that the above
7*ba9bdd8bSchristos * copyright notice and this permission notice appear in all copies.
8*ba9bdd8bSchristos *
9*ba9bdd8bSchristos * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10*ba9bdd8bSchristos * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11*ba9bdd8bSchristos * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12*ba9bdd8bSchristos * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13*ba9bdd8bSchristos * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14*ba9bdd8bSchristos * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15*ba9bdd8bSchristos * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16*ba9bdd8bSchristos */
17*ba9bdd8bSchristos
18*ba9bdd8bSchristos /* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */
19*ba9bdd8bSchristos
20*ba9bdd8bSchristos #include "openbsd-compat.h"
21*ba9bdd8bSchristos
22*ba9bdd8bSchristos #if !defined(HAVE_RECALLOCARRAY)
23*ba9bdd8bSchristos
24*ba9bdd8bSchristos #include <errno.h>
25*ba9bdd8bSchristos #include <stdlib.h>
26*ba9bdd8bSchristos #include <stdint.h>
27*ba9bdd8bSchristos #include <string.h>
28*ba9bdd8bSchristos #ifdef HAVE_UNISTD_H
29*ba9bdd8bSchristos #include <unistd.h>
30*ba9bdd8bSchristos #endif
31*ba9bdd8bSchristos
32*ba9bdd8bSchristos /*
33*ba9bdd8bSchristos * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
34*ba9bdd8bSchristos * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
35*ba9bdd8bSchristos */
36*ba9bdd8bSchristos #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
37*ba9bdd8bSchristos
38*ba9bdd8bSchristos void *
recallocarray(void * ptr,size_t oldnmemb,size_t newnmemb,size_t size)39*ba9bdd8bSchristos recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
40*ba9bdd8bSchristos {
41*ba9bdd8bSchristos size_t oldsize, newsize;
42*ba9bdd8bSchristos void *newptr;
43*ba9bdd8bSchristos
44*ba9bdd8bSchristos if (ptr == NULL)
45*ba9bdd8bSchristos return calloc(newnmemb, size);
46*ba9bdd8bSchristos
47*ba9bdd8bSchristos if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
48*ba9bdd8bSchristos newnmemb > 0 && SIZE_MAX / newnmemb < size) {
49*ba9bdd8bSchristos errno = ENOMEM;
50*ba9bdd8bSchristos return NULL;
51*ba9bdd8bSchristos }
52*ba9bdd8bSchristos newsize = newnmemb * size;
53*ba9bdd8bSchristos
54*ba9bdd8bSchristos if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
55*ba9bdd8bSchristos oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
56*ba9bdd8bSchristos errno = EINVAL;
57*ba9bdd8bSchristos return NULL;
58*ba9bdd8bSchristos }
59*ba9bdd8bSchristos oldsize = oldnmemb * size;
60*ba9bdd8bSchristos
61*ba9bdd8bSchristos /*
62*ba9bdd8bSchristos * Don't bother too much if we're shrinking just a bit,
63*ba9bdd8bSchristos * we do not shrink for series of small steps, oh well.
64*ba9bdd8bSchristos */
65*ba9bdd8bSchristos if (newsize <= oldsize) {
66*ba9bdd8bSchristos size_t d = oldsize - newsize;
67*ba9bdd8bSchristos
68*ba9bdd8bSchristos if (d < oldsize / 2 && d < (size_t)getpagesize()) {
69*ba9bdd8bSchristos memset((char *)ptr + newsize, 0, d);
70*ba9bdd8bSchristos return ptr;
71*ba9bdd8bSchristos }
72*ba9bdd8bSchristos }
73*ba9bdd8bSchristos
74*ba9bdd8bSchristos newptr = malloc(newsize);
75*ba9bdd8bSchristos if (newptr == NULL)
76*ba9bdd8bSchristos return NULL;
77*ba9bdd8bSchristos
78*ba9bdd8bSchristos if (newsize > oldsize) {
79*ba9bdd8bSchristos memcpy(newptr, ptr, oldsize);
80*ba9bdd8bSchristos memset((char *)newptr + oldsize, 0, newsize - oldsize);
81*ba9bdd8bSchristos } else
82*ba9bdd8bSchristos memcpy(newptr, ptr, newsize);
83*ba9bdd8bSchristos
84*ba9bdd8bSchristos explicit_bzero(ptr, oldsize);
85*ba9bdd8bSchristos free(ptr);
86*ba9bdd8bSchristos
87*ba9bdd8bSchristos return newptr;
88*ba9bdd8bSchristos }
89*ba9bdd8bSchristos /* DEF_WEAK(recallocarray); */
90*ba9bdd8bSchristos
91*ba9bdd8bSchristos #endif /* !defined(HAVE_RECALLOCARRAY) */
92