xref: /netbsd-src/external/bsd/tmux/dist/compat/reallocarray.c (revision 4e179ddab96f97aa64efc589ce1918be5318aaaf)
1ed4e6cd4Schristos /*	$OpenBSD: reallocarray.c,v 1.3 2015/09/13 08:31:47 guenther Exp $	*/
2ed4e6cd4Schristos /*
3ed4e6cd4Schristos  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
4ed4e6cd4Schristos  *
5ed4e6cd4Schristos  * Permission to use, copy, modify, and distribute this software for any
6ed4e6cd4Schristos  * purpose with or without fee is hereby granted, provided that the above
7ed4e6cd4Schristos  * copyright notice and this permission notice appear in all copies.
8ed4e6cd4Schristos  *
9ed4e6cd4Schristos  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
10ed4e6cd4Schristos  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
11ed4e6cd4Schristos  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
12ed4e6cd4Schristos  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
13ed4e6cd4Schristos  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
14ed4e6cd4Schristos  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
15ed4e6cd4Schristos  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
16ed4e6cd4Schristos  */
17ed4e6cd4Schristos 
18ed4e6cd4Schristos #include <sys/types.h>
19ed4e6cd4Schristos #include <errno.h>
20ed4e6cd4Schristos #include <stdint.h>
21ed4e6cd4Schristos #include <stdlib.h>
22ed4e6cd4Schristos 
23*4e179ddaSchristos #include "compat.h"
24ed4e6cd4Schristos 
25ed4e6cd4Schristos /*
26ed4e6cd4Schristos  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
27ed4e6cd4Schristos  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
28ed4e6cd4Schristos  */
29ed4e6cd4Schristos #define MUL_NO_OVERFLOW	((size_t)1 << (sizeof(size_t) * 4))
30ed4e6cd4Schristos 
31ed4e6cd4Schristos void *
reallocarray(void * optr,size_t nmemb,size_t size)32ed4e6cd4Schristos reallocarray(void *optr, size_t nmemb, size_t size)
33ed4e6cd4Schristos {
34ed4e6cd4Schristos 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
35ed4e6cd4Schristos 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
36ed4e6cd4Schristos 		errno = ENOMEM;
37ed4e6cd4Schristos 		return NULL;
38ed4e6cd4Schristos 	}
39ed4e6cd4Schristos 	return realloc(optr, size * nmemb);
40ed4e6cd4Schristos }
41