1 /*- 2 * Copyright (c) 2020 The FreeBSD Foundation 3 * 4 * This software was developed by Emmanuel Vadot under sponsorship 5 * from the FreeBSD Foundation. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 * 28 * $FreeBSD$ 29 */ 30 31 #ifndef __LINUX_OVERFLOW_H__ 32 #define __LINUX_OVERFLOW_H__ 33 34 #include <sys/stdint.h> 35 #include <sys/types.h> 36 37 #ifndef __has_builtin 38 #define __has_builtin(x) 0 39 #endif 40 41 #if __has_builtin(__builtin_add_overflow) 42 #define check_add_overflow(a, b, c) \ 43 __builtin_add_overflow(a, b, c) 44 #else 45 #error "Compiler does not support __builtin_add_overflow" 46 #endif 47 48 #if __has_builtin(__builtin_mul_overflow) 49 #define check_mul_overflow(a, b, c) \ 50 __builtin_mul_overflow(a, b, c) 51 52 static inline size_t 53 array_size(size_t x, size_t y) 54 { 55 size_t retval; 56 57 if (__builtin_mul_overflow(x, y, &retval)) 58 retval = SIZE_MAX; 59 return (retval); 60 } 61 #else 62 #error "Compiler does not support __builtin_mul_overflow" 63 #endif 64 65 #endif /* __LINUX_OVERFLOW_H__ */ 66