compiler-rt/lib/safestack/safestack_platform.h

   1 //===-- safestack_platform.h ----------------------------------------------===//
   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 // This file implements platform specific parts of SafeStack runtime.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #ifndef SAFESTACK_PLATFORM_H
  14 #define SAFESTACK_PLATFORM_H
  15
  16 #include "safestack_util.h"
  17 #include "sanitizer_common/sanitizer_platform.h"
  18
  19 #include <dlfcn.h>
  20 #include <stdint.h>
  21 #include <stdio.h>
  22 #include <stdlib.h>
  23 #include <sys/mman.h>
  24 #include <sys/syscall.h>
  25 #include <sys/types.h>
  26 #include <unistd.h>
  27
  28 #if !(SANITIZER_NETBSD || SANITIZER_FREEBSD || SANITIZER_LINUX)
  29 #error "Support for your platform has not been implemented"
  30 #endif
  31
  32 #if SANITIZER_NETBSD
  33 #include <lwp.h>
  34
  35 extern "C" void *__mmap(void *, size_t, int, int, int, int, off_t);
  36 #endif
  37
  38 #if SANITIZER_FREEBSD
  39 #include <sys/thr.h>
  40 #endif
  41
  42 namespace safestack {
  43
  44 #if SANITIZER_NETBSD
  45 static void *GetRealLibcAddress(const char *symbol) {
  46   void *real = dlsym(RTLD_NEXT, symbol);
  47   if (!real)
  48     real = dlsym(RTLD_DEFAULT, symbol);
  49   if (!real) {
  50     fprintf(stderr, "safestack GetRealLibcAddress failed for symbol=%s",
  51             symbol);
  52     abort();
  53   }
  54   return real;
  55 }
  56
  57 #define _REAL(func, ...) real##_##func(__VA_ARGS__)
  58 #define DEFINE__REAL(ret_type, func, ...)                              \
  59   static ret_type (*real_##func)(__VA_ARGS__) = NULL;                  \
  60   if (!real_##func) {                                                  \
  61     real_##func = (ret_type(*)(__VA_ARGS__))GetRealLibcAddress(#func); \
  62   }                                                                    \
  63   SFS_CHECK(real_##func);
  64 #endif
  65
  66 using ThreadId = uint64_t;
  67
  68 inline ThreadId GetTid() {
  69 #if SANITIZER_NETBSD
  70   DEFINE__REAL(int, _lwp_self);
  71   return _REAL(_lwp_self);
  72 #elif SANITIZER_FREEBSD
  73   long Tid;
  74   thr_self(&Tid);
  75   return Tid;
  76 #else
  77   return syscall(SYS_gettid);
  78 #endif
  79 }
  80
  81 inline int TgKill(pid_t pid, ThreadId tid, int sig) {
  82 #if SANITIZER_NETBSD
  83   DEFINE__REAL(int, _lwp_kill, int a, int b);
  84   (void)pid;
  85   return _REAL(_lwp_kill, tid, sig);
  86 #elif SANITIZER_FREEBSD
  87   return syscall(SYS_thr_kill2, pid, tid, sig);
  88 #else
  89   return syscall(SYS_tgkill, pid, tid, sig);
  90 #endif
  91 }
  92
  93 inline void *Mmap(void *addr, size_t length, int prot, int flags, int fd,
  94                   off_t offset) {
  95 #if SANITIZER_NETBSD
  96   return __mmap(addr, length, prot, flags, fd, 0, offset);
  97 #elif SANITIZER_FREEBSD && (defined(__aarch64__) || defined(__x86_64__))
  98   return (void *)__syscall(SYS_mmap, addr, length, prot, flags, fd, offset);
  99 #else
 100   return (void *)syscall(SYS_mmap, addr, length, prot, flags, fd, offset);
 101 #endif
 102 }
 103
 104 inline int Munmap(void *addr, size_t length) {
 105 #if SANITIZER_NETBSD
 106   DEFINE__REAL(int, munmap, void *a, size_t b);
 107   return _REAL(munmap, addr, length);
 108 #else
 109   return syscall(SYS_munmap, addr, length);
 110 #endif
 111 }
 112
 113 inline int Mprotect(void *addr, size_t length, int prot) {
 114 #if SANITIZER_NETBSD
 115   DEFINE__REAL(int, mprotect, void *a, size_t b, int c);
 116   return _REAL(mprotect, addr, length, prot);
 117 #else
 118   return syscall(SYS_mprotect, addr, length, prot);
 119 #endif
 120 }
 121
 122 }  // namespace safestack
 123
 124 #endif  // SAFESTACK_PLATFORM_H