1 //===-- wrappers_c_checks.h -------------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef SCUDO_CHECKS_H_ 10 #define SCUDO_CHECKS_H_ 11 12 #include "common.h" 13 14 #include <errno.h> 15 16 #ifndef __has_builtin 17 #define __has_builtin(X) 0 18 #endif 19 20 namespace scudo { 21 22 // A common errno setting logic shared by almost all Scudo C wrappers. 23 inline void *setErrnoOnNull(void *Ptr) { 24 if (UNLIKELY(!Ptr)) 25 errno = ENOMEM; 26 return Ptr; 27 } 28 29 // Checks return true on failure. 30 31 // Checks aligned_alloc() parameters, verifies that the alignment is a power of 32 // two and that the size is a multiple of alignment. 33 inline bool checkAlignedAllocAlignmentAndSize(uptr Alignment, uptr Size) { 34 return Alignment == 0 || !isPowerOfTwo(Alignment) || 35 !isAligned(Size, Alignment); 36 } 37 38 // Checks posix_memalign() parameters, verifies that alignment is a power of two 39 // and a multiple of sizeof(void *). 40 inline bool checkPosixMemalignAlignment(uptr Alignment) { 41 return Alignment == 0 || !isPowerOfTwo(Alignment) || 42 !isAligned(Alignment, sizeof(void *)); 43 } 44 45 // Returns true if calloc(Size, N) overflows on Size*N calculation. Use a 46 // builtin supported by recent clang & GCC if it exists, otherwise fallback to a 47 // costly division. 48 inline bool checkForCallocOverflow(uptr Size, uptr N, uptr *Product) { 49 #if __has_builtin(__builtin_umull_overflow) && (SCUDO_WORDSIZE == 64U) 50 return __builtin_umull_overflow(Size, N, Product); 51 #elif __has_builtin(__builtin_umul_overflow) && (SCUDO_WORDSIZE == 32U) 52 return __builtin_umul_overflow(Size, N, Product); 53 #else 54 *Product = Size * N; 55 if (!Size) 56 return false; 57 return (*Product / Size) != N; 58 #endif 59 } 60 61 // Returns true if the size passed to pvalloc overflows when rounded to the next 62 // multiple of PageSize. 63 inline bool checkForPvallocOverflow(uptr Size, uptr PageSize) { 64 return roundUpTo(Size, PageSize) < Size; 65 } 66 67 } // namespace scudo 68 69 #endif // SCUDO_CHECKS_H_ 70