1 c423c56e 2022-09-25 op /*	$OpenBSD: reallocarray.c,v 1.3 2015/09/13 08:31:47 guenther Exp $	*/
 2 c423c56e 2022-09-25 op /*
 3 c423c56e 2022-09-25 op  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
 4 c423c56e 2022-09-25 op  *
 5 c423c56e 2022-09-25 op  * Permission to use, copy, modify, and distribute this software for any
 6 c423c56e 2022-09-25 op  * purpose with or without fee is hereby granted, provided that the above
 7 c423c56e 2022-09-25 op  * copyright notice and this permission notice appear in all copies.
 8 c423c56e 2022-09-25 op  *
 9 c423c56e 2022-09-25 op  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10 c423c56e 2022-09-25 op  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11 c423c56e 2022-09-25 op  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12 c423c56e 2022-09-25 op  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13 c423c56e 2022-09-25 op  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14 c423c56e 2022-09-25 op  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15 c423c56e 2022-09-25 op  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16 c423c56e 2022-09-25 op  */
17 c423c56e 2022-09-25 op 
18 c423c56e 2022-09-25 op #include <sys/types.h>
19 c423c56e 2022-09-25 op #include <errno.h>
20 c423c56e 2022-09-25 op #include <stdint.h>
21 c423c56e 2022-09-25 op #include <stdlib.h>
22 c423c56e 2022-09-25 op 
23 c423c56e 2022-09-25 op /*
24 c423c56e 2022-09-25 op  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
25 c423c56e 2022-09-25 op  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
26 c423c56e 2022-09-25 op  */
27 c423c56e 2022-09-25 op #define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
28 c423c56e 2022-09-25 op 
29 c423c56e 2022-09-25 op void *
30 c423c56e 2022-09-25 op reallocarray(void *optr, size_t nmemb, size_t size)
31 c423c56e 2022-09-25 op {
32 c423c56e 2022-09-25 op 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
33 c423c56e 2022-09-25 op 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
34 c423c56e 2022-09-25 op 		errno = ENOMEM;
35 c423c56e 2022-09-25 op 		return NULL;
36 c423c56e 2022-09-25 op 	}
37 c423c56e 2022-09-25 op 	return realloc(optr, size * nmemb);
38 c423c56e 2022-09-25 op }