| 1 | //===-- wrappers_c_checks.h -------------------------------------*- C++ -*-===// |
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| 2 | // |
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| 3 | // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
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| 4 | // See https://llvm.org/LICENSE.txt for license information. |
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| 5 | // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
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| 6 | // |
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| 7 | //===----------------------------------------------------------------------===// |
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| 8 | |
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| 9 | #ifndef SCUDO_CHECKS_H_ |
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| 10 | #define SCUDO_CHECKS_H_ |
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| 11 | |
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| 12 | #include "common.h" |
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| 13 | |
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| 14 | #include <errno.h> |
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| 15 | |
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| 16 | #ifndef __has_builtin |
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| 17 | #define __has_builtin(X) 0 |
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| 18 | #endif |
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| 19 | |
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| 20 | namespace scudo { |
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| 21 | |
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| 22 | // A common errno setting logic shared by almost all Scudo C wrappers. |
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| 23 | inline void *setErrnoOnNull(void *Ptr) { |
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| 24 | if (UNLIKELY(!Ptr)) |
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| 25 | errno = ENOMEM; |
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| 26 | return Ptr; |
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| 27 | } |
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| 28 | |
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| 29 | // Checks return true on failure. |
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| 30 | |
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| 31 | // Checks aligned_alloc() parameters, verifies that the alignment is a power of |
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| 32 | // two and that the size is a multiple of alignment. |
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| 33 | inline bool checkAlignedAllocAlignmentAndSize(uptr Alignment, uptr Size) { |
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| 34 | return !isPowerOfTwo(X: Alignment) || !isAligned(X: Size, Alignment); |
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| 35 | } |
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| 36 | |
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| 37 | // Checks posix_memalign() parameters, verifies that alignment is a power of two |
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| 38 | // and a multiple of sizeof(void *). |
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| 39 | inline bool checkPosixMemalignAlignment(uptr Alignment) { |
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| 40 | return !isPowerOfTwo(X: Alignment) || !isAligned(X: Alignment, Alignment: sizeof(void *)); |
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| 41 | } |
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| 42 | |
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| 43 | // Returns true if calloc(Size, N) overflows on Size*N calculation. Use a |
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| 44 | // builtin supported by recent clang & GCC if it exists, otherwise fallback to a |
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| 45 | // costly division. |
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| 46 | inline bool checkForCallocOverflow(uptr Size, uptr N, uptr *Product) { |
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| 47 | #if __has_builtin(__builtin_umull_overflow) && (SCUDO_WORDSIZE == 64U) |
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| 48 | return __builtin_umull_overflow(Size, N, |
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| 49 | reinterpret_cast<unsigned long *>(Product)); |
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| 50 | #elif __has_builtin(__builtin_umul_overflow) && (SCUDO_WORDSIZE == 32U) |
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| 51 | // On, e.g. armv7, uptr/uintptr_t may be defined as unsigned long |
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| 52 | return __builtin_umul_overflow(Size, N, |
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| 53 | reinterpret_cast<unsigned int *>(Product)); |
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| 54 | #else |
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| 55 | *Product = Size * N; |
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| 56 | if (!Size) |
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| 57 | return false; |
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| 58 | return (*Product / Size) != N; |
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| 59 | #endif |
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| 60 | } |
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| 61 | |
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| 62 | // Returns true if the size passed to pvalloc overflows when rounded to the next |
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| 63 | // multiple of PageSize. |
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| 64 | inline bool checkForPvallocOverflow(uptr Size, uptr PageSize) { |
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| 65 | return roundUp(X: Size, Boundary: PageSize) < Size; |
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| 66 | } |
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| 67 | |
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| 68 | } // namespace scudo |
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| 69 | |
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| 70 | #endif // SCUDO_CHECKS_H_ |
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| 71 | |
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