1 805e39bf 2021-07-22 op /*
 2 805e39bf 2021-07-22 op  * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
 3 805e39bf 2021-07-22 op  *
 4 805e39bf 2021-07-22 op  * Permission to use, copy, modify, and distribute this software for any
 5 805e39bf 2021-07-22 op  * purpose with or without fee is hereby granted, provided that the above
 6 805e39bf 2021-07-22 op  * copyright notice and this permission notice appear in all copies.
 7 805e39bf 2021-07-22 op  *
 8 805e39bf 2021-07-22 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 9 805e39bf 2021-07-22 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 805e39bf 2021-07-22 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 805e39bf 2021-07-22 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 805e39bf 2021-07-22 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 805e39bf 2021-07-22 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 805e39bf 2021-07-22 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 805e39bf 2021-07-22 op  */
16 805e39bf 2021-07-22 op 
17 805e39bf 2021-07-22 op #include "compat.h"
18 805e39bf 2021-07-22 op 
19 805e39bf 2021-07-22 op #include <errno.h>
20 805e39bf 2021-07-22 op #include <stdlib.h>
21 805e39bf 2021-07-22 op #include <stdint.h>
22 805e39bf 2021-07-22 op #include <string.h>
23 805e39bf 2021-07-22 op #include <unistd.h>
24 805e39bf 2021-07-22 op 
25 805e39bf 2021-07-22 op /*
26 805e39bf 2021-07-22 op  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
27 805e39bf 2021-07-22 op  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
28 805e39bf 2021-07-22 op  */
29 805e39bf 2021-07-22 op #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
30 805e39bf 2021-07-22 op 
31 805e39bf 2021-07-22 op /*
32 805e39bf 2021-07-22 op  * Even though specified in POSIX, the PAGESIZE and PAGE_SIZE
33 805e39bf 2021-07-22 op  * macros have very poor portability.  Since we only use this
34 805e39bf 2021-07-22 op  * to avoid free() overhead for small shrinking, simply pick
35 805e39bf 2021-07-22 op  * an arbitrary number.
36 805e39bf 2021-07-22 op  */
37 805e39bf 2021-07-22 op #define getpagesize()	(1UL << 12)
38 805e39bf 2021-07-22 op 
39 805e39bf 2021-07-22 op void *
40 805e39bf 2021-07-22 op recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
41 805e39bf 2021-07-22 op {
42 805e39bf 2021-07-22 op 	size_t oldsize, newsize;
43 805e39bf 2021-07-22 op 	void *newptr;
44 805e39bf 2021-07-22 op 
45 805e39bf 2021-07-22 op 	if (ptr == NULL)
46 805e39bf 2021-07-22 op 		return calloc(newnmemb, size);
47 805e39bf 2021-07-22 op 
48 805e39bf 2021-07-22 op 	if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
49 805e39bf 2021-07-22 op 	    newnmemb > 0 && SIZE_MAX / newnmemb < size) {
50 805e39bf 2021-07-22 op 		errno = ENOMEM;
51 805e39bf 2021-07-22 op 		return NULL;
52 805e39bf 2021-07-22 op 	}
53 805e39bf 2021-07-22 op 	newsize = newnmemb * size;
54 805e39bf 2021-07-22 op 
55 805e39bf 2021-07-22 op 	if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
56 805e39bf 2021-07-22 op 	    oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
57 805e39bf 2021-07-22 op 		errno = EINVAL;
58 805e39bf 2021-07-22 op 		return NULL;
59 805e39bf 2021-07-22 op 	}
60 805e39bf 2021-07-22 op 	oldsize = oldnmemb * size;
61 805e39bf 2021-07-22 op 
62 805e39bf 2021-07-22 op 	/*
63 805e39bf 2021-07-22 op 	 * Don't bother too much if we're shrinking just a bit,
64 805e39bf 2021-07-22 op 	 * we do not shrink for series of small steps, oh well.
65 805e39bf 2021-07-22 op 	 */
66 805e39bf 2021-07-22 op 	if (newsize <= oldsize) {
67 805e39bf 2021-07-22 op 		size_t d = oldsize - newsize;
68 805e39bf 2021-07-22 op 
69 805e39bf 2021-07-22 op 		if (d < oldsize / 2 && d < getpagesize()) {
70 805e39bf 2021-07-22 op 			memset((char *)ptr + newsize, 0, d);
71 805e39bf 2021-07-22 op 			return ptr;
72 805e39bf 2021-07-22 op 		}
73 805e39bf 2021-07-22 op 	}
74 805e39bf 2021-07-22 op 
75 805e39bf 2021-07-22 op 	newptr = malloc(newsize);
76 805e39bf 2021-07-22 op 	if (newptr == NULL)
77 805e39bf 2021-07-22 op 		return NULL;
78 805e39bf 2021-07-22 op 
79 805e39bf 2021-07-22 op 	if (newsize > oldsize) {
80 805e39bf 2021-07-22 op 		memcpy(newptr, ptr, oldsize);
81 805e39bf 2021-07-22 op 		memset((char *)newptr + oldsize, 0, newsize - oldsize);
82 805e39bf 2021-07-22 op 	} else
83 805e39bf 2021-07-22 op 		memcpy(newptr, ptr, newsize);
84 805e39bf 2021-07-22 op 
85 805e39bf 2021-07-22 op 	explicit_bzero(ptr, oldsize);
86 805e39bf 2021-07-22 op 	free(ptr);
87 805e39bf 2021-07-22 op 
88 805e39bf 2021-07-22 op 	return newptr;
89 805e39bf 2021-07-22 op }