1*dbd5d9cdSchristos /* $OpenBSD: recallocarray.c,v 1.1 2017/03/06 18:44:21 otto Exp $ */
226b9f775Schristos
3*dbd5d9cdSchristos /*
4*dbd5d9cdSchristos * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
526b9f775Schristos *
6*dbd5d9cdSchristos * Permission to use, copy, modify, and distribute this software for any
7*dbd5d9cdSchristos * purpose with or without fee is hereby granted, provided that the above
8*dbd5d9cdSchristos * copyright notice and this permission notice appear in all copies.
926b9f775Schristos *
10*dbd5d9cdSchristos * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11*dbd5d9cdSchristos * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12*dbd5d9cdSchristos * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13*dbd5d9cdSchristos * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14*dbd5d9cdSchristos * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15*dbd5d9cdSchristos * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16*dbd5d9cdSchristos * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
1726b9f775Schristos */
1826b9f775Schristos
19*dbd5d9cdSchristos /* OPENBSD ORIGINAL: lib/libc/stdlib/recallocarray.c */
20*dbd5d9cdSchristos
2126b9f775Schristos #include "includes.h"
22*dbd5d9cdSchristos #ifndef HAVE_RECALLOCARRAY
2326b9f775Schristos
2426b9f775Schristos #include <errno.h>
2526b9f775Schristos #include <stdlib.h>
26*dbd5d9cdSchristos #ifdef HAVE_STDINT_H
27*dbd5d9cdSchristos #include <stdint.h>
28*dbd5d9cdSchristos #endif
29*dbd5d9cdSchristos #include <string.h>
30*dbd5d9cdSchristos #include <unistd.h>
31*dbd5d9cdSchristos
32*dbd5d9cdSchristos /*
33*dbd5d9cdSchristos * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
34*dbd5d9cdSchristos * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
35*dbd5d9cdSchristos */
36*dbd5d9cdSchristos #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
3726b9f775Schristos
3826b9f775Schristos void *
recallocarray(void * ptr,size_t oldnmemb,size_t newnmemb,size_t size)39*dbd5d9cdSchristos recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
4026b9f775Schristos {
41*dbd5d9cdSchristos size_t oldsize, newsize;
42*dbd5d9cdSchristos void *newptr;
4326b9f775Schristos
44*dbd5d9cdSchristos if (ptr == NULL)
45*dbd5d9cdSchristos return calloc(newnmemb, size);
4626b9f775Schristos
47*dbd5d9cdSchristos if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
48*dbd5d9cdSchristos newnmemb > 0 && SIZE_MAX / newnmemb < size) {
49*dbd5d9cdSchristos errno = ENOMEM;
50*dbd5d9cdSchristos return NULL;
5126b9f775Schristos }
52*dbd5d9cdSchristos newsize = newnmemb * size;
53*dbd5d9cdSchristos
54*dbd5d9cdSchristos if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
55*dbd5d9cdSchristos oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
56*dbd5d9cdSchristos errno = EINVAL;
57*dbd5d9cdSchristos return NULL;
58*dbd5d9cdSchristos }
59*dbd5d9cdSchristos oldsize = oldnmemb * size;
60*dbd5d9cdSchristos
61*dbd5d9cdSchristos /*
62*dbd5d9cdSchristos * Don't bother too much if we're shrinking just a bit,
63*dbd5d9cdSchristos * we do not shrink for series of small steps, oh well.
64*dbd5d9cdSchristos */
65*dbd5d9cdSchristos if (newsize <= oldsize) {
66*dbd5d9cdSchristos size_t d = oldsize - newsize;
67*dbd5d9cdSchristos
68*dbd5d9cdSchristos if (d < oldsize / 2 && d < (size_t)getpagesize()) {
69*dbd5d9cdSchristos memset((char *)ptr + newsize, 0, d);
70*dbd5d9cdSchristos return ptr;
71*dbd5d9cdSchristos }
72*dbd5d9cdSchristos }
73*dbd5d9cdSchristos
74*dbd5d9cdSchristos newptr = malloc(newsize);
75*dbd5d9cdSchristos if (newptr == NULL)
76*dbd5d9cdSchristos return NULL;
77*dbd5d9cdSchristos
78*dbd5d9cdSchristos if (newsize > oldsize) {
79*dbd5d9cdSchristos memcpy(newptr, ptr, oldsize);
80*dbd5d9cdSchristos memset((char *)newptr + oldsize, 0, newsize - oldsize);
81*dbd5d9cdSchristos } else
82*dbd5d9cdSchristos memcpy(newptr, ptr, newsize);
83*dbd5d9cdSchristos
84*dbd5d9cdSchristos explicit_bzero(ptr, oldsize);
85*dbd5d9cdSchristos free(ptr);
86*dbd5d9cdSchristos
87*dbd5d9cdSchristos return newptr;
88*dbd5d9cdSchristos }
89*dbd5d9cdSchristos /* DEF_WEAK(recallocarray); */
90*dbd5d9cdSchristos
91*dbd5d9cdSchristos #endif /* HAVE_RECALLOCARRAY */
92