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