compiler-rt/lib/scudo/standalone/wrappers_c_checks.h

   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,
  51                                   reinterpret_cast<unsigned long *>(Product));
  52 #elif __has_builtin(__builtin_umul_overflow) && (SCUDO_WORDSIZE == 32U)
  53   // On, e.g. armv7, uptr/uintptr_t may be defined as unsigned long
  54   return __builtin_umul_overflow(Size, N,
  55                                  reinterpret_cast<unsigned int *>(Product));
  56 #else
  57   *Product = Size * N;
  58   if (!Size)
  59     return false;
  60   return (*Product / Size) != N;
  61 #endif
  62 }
  63
  64 // Returns true if the size passed to pvalloc overflows when rounded to the next
  65 // multiple of PageSize.
  66 inline bool checkForPvallocOverflow(uptr Size, uptr PageSize) {
  67   return roundUp(Size, PageSize) < Size;
  68 }
  69
  70 } // namespace scudo
  71
  72 #endif // SCUDO_CHECKS_H_