libsanitizer/sanitizer_common/sanitizer_getauxval.h

   1 //===-- sanitizer_getauxval.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 // Common getauxval() guards and definitions.
  10 // getauxval() is not defined until glibc version 2.16, or until API level 21
  11 // for Android.
  12 // Implement the getauxval() compat function for NetBSD.
  13 //
  14 //===----------------------------------------------------------------------===//
  15
  16 #ifndef SANITIZER_GETAUXVAL_H
  17 #define SANITIZER_GETAUXVAL_H
  18
  19 #include "sanitizer_platform.h"
  20 #include "sanitizer_glibc_version.h"
  21
  22 #if SANITIZER_LINUX || SANITIZER_FUCHSIA
  23
  24 # if (__GLIBC_PREREQ(2, 16) || (SANITIZER_ANDROID && __ANDROID_API__ >= 21) || \
  25       SANITIZER_FUCHSIA) &&                                                    \
  26      !SANITIZER_GO
  27 #  define SANITIZER_USE_GETAUXVAL 1
  28 # else
  29 #  define SANITIZER_USE_GETAUXVAL 0
  30 # endif
  31
  32 # if SANITIZER_USE_GETAUXVAL
  33 #  include <sys/auxv.h>
  34 # else
  35 // The weak getauxval definition allows to check for the function at runtime.
  36 // This is useful for Android, when compiled at a lower API level yet running
  37 // on a more recent platform that offers the function.
  38 extern "C" SANITIZER_WEAK_ATTRIBUTE unsigned long getauxval(unsigned long type);
  39 # endif
  40
  41 #elif SANITIZER_NETBSD
  42
  43 #define SANITIZER_USE_GETAUXVAL 1
  44
  45 #include <dlfcn.h>
  46 #include <elf.h>
  47
  48 static inline decltype(AuxInfo::a_v) getauxval(decltype(AuxInfo::a_type) type) {
  49   for (const AuxInfo *aux = (const AuxInfo *)_dlauxinfo();
  50        aux->a_type != AT_NULL; ++aux) {
  51     if (type == aux->a_type)
  52       return aux->a_v;
  53   }
  54
  55   return 0;
  56 }
  57
  58 #endif
  59
  60 #endif // SANITIZER_GETAUXVAL_H