1*f1cdbd37SYuri Pankov /*
2*f1cdbd37SYuri Pankov * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
3*f1cdbd37SYuri Pankov *
4*f1cdbd37SYuri Pankov * Permission to use, copy, modify, and distribute this software for any
5*f1cdbd37SYuri Pankov * purpose with or without fee is hereby granted, provided that the above
6*f1cdbd37SYuri Pankov * copyright notice and this permission notice appear in all copies.
7*f1cdbd37SYuri Pankov *
8*f1cdbd37SYuri Pankov * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
9*f1cdbd37SYuri Pankov * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10*f1cdbd37SYuri Pankov * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11*f1cdbd37SYuri Pankov * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12*f1cdbd37SYuri Pankov * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13*f1cdbd37SYuri Pankov * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14*f1cdbd37SYuri Pankov * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15*f1cdbd37SYuri Pankov */
16*f1cdbd37SYuri Pankov
17*f1cdbd37SYuri Pankov #include <errno.h>
18*f1cdbd37SYuri Pankov #include <stdlib.h>
19*f1cdbd37SYuri Pankov #include <stdint.h>
20*f1cdbd37SYuri Pankov #include <string.h>
21*f1cdbd37SYuri Pankov #include <unistd.h>
22*f1cdbd37SYuri Pankov
23*f1cdbd37SYuri Pankov /*
24*f1cdbd37SYuri Pankov * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
25*f1cdbd37SYuri Pankov * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
26*f1cdbd37SYuri Pankov */
27*f1cdbd37SYuri Pankov #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof (size_t) * 4))
28*f1cdbd37SYuri Pankov
29*f1cdbd37SYuri Pankov void *
recallocarray(void * ptr,size_t oldnelem,size_t newnelem,size_t elsize)30*f1cdbd37SYuri Pankov recallocarray(void *ptr, size_t oldnelem, size_t newnelem, size_t elsize)
31*f1cdbd37SYuri Pankov {
32*f1cdbd37SYuri Pankov size_t oldsize, newsize;
33*f1cdbd37SYuri Pankov void *newptr;
34*f1cdbd37SYuri Pankov
35*f1cdbd37SYuri Pankov if (ptr == NULL)
36*f1cdbd37SYuri Pankov return (calloc(newnelem, elsize));
37*f1cdbd37SYuri Pankov
38*f1cdbd37SYuri Pankov if ((newnelem >= MUL_NO_OVERFLOW || elsize >= MUL_NO_OVERFLOW) &&
39*f1cdbd37SYuri Pankov newnelem > 0 && SIZE_MAX / newnelem < elsize) {
40*f1cdbd37SYuri Pankov errno = ENOMEM;
41*f1cdbd37SYuri Pankov return (NULL);
42*f1cdbd37SYuri Pankov }
43*f1cdbd37SYuri Pankov newsize = newnelem * elsize;
44*f1cdbd37SYuri Pankov
45*f1cdbd37SYuri Pankov if ((oldnelem >= MUL_NO_OVERFLOW || elsize >= MUL_NO_OVERFLOW) &&
46*f1cdbd37SYuri Pankov oldnelem > 0 && SIZE_MAX / oldnelem < elsize) {
47*f1cdbd37SYuri Pankov errno = EINVAL;
48*f1cdbd37SYuri Pankov return (NULL);
49*f1cdbd37SYuri Pankov }
50*f1cdbd37SYuri Pankov oldsize = oldnelem * elsize;
51*f1cdbd37SYuri Pankov
52*f1cdbd37SYuri Pankov /*
53*f1cdbd37SYuri Pankov * Don't bother too much if we're shrinking just a bit,
54*f1cdbd37SYuri Pankov * we do not shrink for series of small steps, oh well.
55*f1cdbd37SYuri Pankov */
56*f1cdbd37SYuri Pankov if (newsize <= oldsize) {
57*f1cdbd37SYuri Pankov size_t d = oldsize - newsize;
58*f1cdbd37SYuri Pankov
59*f1cdbd37SYuri Pankov if (d < oldsize / 2 && d < getpagesize()) {
60*f1cdbd37SYuri Pankov (void) memset((char *)ptr + newsize, 0, d);
61*f1cdbd37SYuri Pankov return (ptr);
62*f1cdbd37SYuri Pankov }
63*f1cdbd37SYuri Pankov }
64*f1cdbd37SYuri Pankov
65*f1cdbd37SYuri Pankov newptr = malloc(newsize);
66*f1cdbd37SYuri Pankov if (newptr == NULL)
67*f1cdbd37SYuri Pankov return (NULL);
68*f1cdbd37SYuri Pankov
69*f1cdbd37SYuri Pankov if (newsize > oldsize) {
70*f1cdbd37SYuri Pankov (void) memcpy(newptr, ptr, oldsize);
71*f1cdbd37SYuri Pankov (void) memset((char *)newptr + oldsize, 0, newsize - oldsize);
72*f1cdbd37SYuri Pankov } else {
73*f1cdbd37SYuri Pankov (void) memcpy(newptr, ptr, newsize);
74*f1cdbd37SYuri Pankov }
75*f1cdbd37SYuri Pankov
76*f1cdbd37SYuri Pankov explicit_bzero(ptr, oldsize);
77*f1cdbd37SYuri Pankov free(ptr);
78*f1cdbd37SYuri Pankov
79*f1cdbd37SYuri Pankov return (newptr);
80*f1cdbd37SYuri Pankov }
81