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.
setErrnoOnNull(void * Ptr)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.
checkAlignedAllocAlignmentAndSize(uptr Alignment,uptr Size)33 inline bool checkAlignedAllocAlignmentAndSize(uptr Alignment, uptr Size) {
34 return !isPowerOfTwo(Alignment) || !isAligned(Size, Alignment);
35 }
36
37 // Checks posix_memalign() parameters, verifies that alignment is a power of two
38 // and a multiple of sizeof(void *).
checkPosixMemalignAlignment(uptr Alignment)39 inline bool checkPosixMemalignAlignment(uptr Alignment) {
40 return !isPowerOfTwo(Alignment) || !isAligned(Alignment, sizeof(void *));
41 }
42
43 // Returns true if calloc(Size, N) overflows on Size*N calculation. Use a
44 // builtin supported by recent clang & GCC if it exists, otherwise fallback to a
45 // costly division.
checkForCallocOverflow(uptr Size,uptr N,uptr * Product)46 inline bool checkForCallocOverflow(uptr Size, uptr N, uptr *Product) {
47 #if __has_builtin(__builtin_umull_overflow) && (SCUDO_WORDSIZE == 64U)
48 return __builtin_umull_overflow(Size, N,
49 reinterpret_cast<unsigned long *>(Product));
50 #elif __has_builtin(__builtin_umul_overflow) && (SCUDO_WORDSIZE == 32U)
51 // On, e.g. armv7, uptr/uintptr_t may be defined as unsigned long
52 return __builtin_umul_overflow(Size, N,
53 reinterpret_cast<unsigned int *>(Product));
54 #else
55 *Product = Size * N;
56 if (!Size)
57 return false;
58 return (*Product / Size) != N;
59 #endif
60 }
61
62 // Returns true if the size passed to pvalloc overflows when rounded to the next
63 // multiple of PageSize.
checkForPvallocOverflow(uptr Size,uptr PageSize)64 inline bool checkForPvallocOverflow(uptr Size, uptr PageSize) {
65 return roundUp(Size, PageSize) < Size;
66 }
67
68 } // namespace scudo
69
70 #endif // SCUDO_CHECKS_H_
71