1 5c342d05 2021-01-21 op /*
 2 5c342d05 2021-01-21 op  * Copyright (c) 2008, 2017 Otto Moerbeek <otto@drijf.net>
 3 5c342d05 2021-01-21 op  *
 4 5c342d05 2021-01-21 op  * Permission to use, copy, modify, and distribute this software for any
 5 5c342d05 2021-01-21 op  * purpose with or without fee is hereby granted, provided that the above
 6 5c342d05 2021-01-21 op  * copyright notice and this permission notice appear in all copies.
 7 5c342d05 2021-01-21 op  *
 8 5c342d05 2021-01-21 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 9 5c342d05 2021-01-21 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
10 5c342d05 2021-01-21 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
11 5c342d05 2021-01-21 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
12 5c342d05 2021-01-21 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
13 5c342d05 2021-01-21 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
14 5c342d05 2021-01-21 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
15 5c342d05 2021-01-21 op  */
16 5c342d05 2021-01-21 op 
17 5c342d05 2021-01-21 op #include <errno.h>
18 5c342d05 2021-01-21 op #include <stdlib.h>
19 5c342d05 2021-01-21 op #include <stdint.h>
20 5c342d05 2021-01-21 op #include <string.h>
21 5c342d05 2021-01-21 op #include <unistd.h>
22 5c342d05 2021-01-21 op 
23 5c342d05 2021-01-21 op /*
24 5c342d05 2021-01-21 op  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
25 5c342d05 2021-01-21 op  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
26 5c342d05 2021-01-21 op  */
27 5c342d05 2021-01-21 op #define MUL_NO_OVERFLOW ((size_t)1 << (sizeof(size_t) * 4))
28 5c342d05 2021-01-21 op 
29 5c342d05 2021-01-21 op /*
30 5c342d05 2021-01-21 op  * Even though specified in POSIX, the PAGESIZE and PAGE_SIZE
31 5c342d05 2021-01-21 op  * macros have very poor portability.  Since we only use this
32 5c342d05 2021-01-21 op  * to avoid free() overhead for small shrinking, simply pick
33 5c342d05 2021-01-21 op  * an arbitrary number.
34 5c342d05 2021-01-21 op  */
35 5c342d05 2021-01-21 op #define getpagesize()	(1UL << 12)
36 5c342d05 2021-01-21 op 
37 5c342d05 2021-01-21 op /* cheat: provide a prototype for explicit_bzero: if libc doesn't
38 5c342d05 2021-01-21 op  * provide it, we will link to compat/explicit_bzero.c anyway. */
39 5c342d05 2021-01-21 op void explicit_bzero(void*, size_t);
40 5c342d05 2021-01-21 op 
41 5c342d05 2021-01-21 op void *
42 5c342d05 2021-01-21 op recallocarray(void *ptr, size_t oldnmemb, size_t newnmemb, size_t size)
43 5c342d05 2021-01-21 op {
44 5c342d05 2021-01-21 op 	size_t oldsize, newsize;
45 5c342d05 2021-01-21 op 	void *newptr;
46 5c342d05 2021-01-21 op 
47 5c342d05 2021-01-21 op 	if (ptr == NULL)
48 5c342d05 2021-01-21 op 		return calloc(newnmemb, size);
49 5c342d05 2021-01-21 op 
50 5c342d05 2021-01-21 op 	if ((newnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
51 5c342d05 2021-01-21 op 	    newnmemb > 0 && SIZE_MAX / newnmemb < size) {
52 5c342d05 2021-01-21 op 		errno = ENOMEM;
53 5c342d05 2021-01-21 op 		return NULL;
54 5c342d05 2021-01-21 op 	}
55 5c342d05 2021-01-21 op 	newsize = newnmemb * size;
56 5c342d05 2021-01-21 op 
57 5c342d05 2021-01-21 op 	if ((oldnmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
58 5c342d05 2021-01-21 op 	    oldnmemb > 0 && SIZE_MAX / oldnmemb < size) {
59 5c342d05 2021-01-21 op 		errno = EINVAL;
60 5c342d05 2021-01-21 op 		return NULL;
61 5c342d05 2021-01-21 op 	}
62 5c342d05 2021-01-21 op 	oldsize = oldnmemb * size;
63 5c342d05 2021-01-21 op 
64 5c342d05 2021-01-21 op 	/*
65 5c342d05 2021-01-21 op 	 * Don't bother too much if we're shrinking just a bit,
66 5c342d05 2021-01-21 op 	 * we do not shrink for series of small steps, oh well.
67 5c342d05 2021-01-21 op 	 */
68 5c342d05 2021-01-21 op 	if (newsize <= oldsize) {
69 5c342d05 2021-01-21 op 		size_t d = oldsize - newsize;
70 5c342d05 2021-01-21 op 
71 5c342d05 2021-01-21 op 		if (d < oldsize / 2 && d < getpagesize()) {
72 5c342d05 2021-01-21 op 			memset((char *)ptr + newsize, 0, d);
73 5c342d05 2021-01-21 op 			return ptr;
74 5c342d05 2021-01-21 op 		}
75 5c342d05 2021-01-21 op 	}
76 5c342d05 2021-01-21 op 
77 5c342d05 2021-01-21 op 	newptr = malloc(newsize);
78 5c342d05 2021-01-21 op 	if (newptr == NULL)
79 5c342d05 2021-01-21 op 		return NULL;
80 5c342d05 2021-01-21 op 
81 5c342d05 2021-01-21 op 	if (newsize > oldsize) {
82 5c342d05 2021-01-21 op 		memcpy(newptr, ptr, oldsize);
83 5c342d05 2021-01-21 op 		memset((char *)newptr + oldsize, 0, newsize - oldsize);
84 5c342d05 2021-01-21 op 	} else
85 5c342d05 2021-01-21 op 		memcpy(newptr, ptr, newsize);
86 5c342d05 2021-01-21 op 
87 5c342d05 2021-01-21 op 	explicit_bzero(ptr, oldsize);
88 5c342d05 2021-01-21 op 	free(ptr);
89 5c342d05 2021-01-21 op 
90 5c342d05 2021-01-21 op 	return newptr;
91 5c342d05 2021-01-21 op }