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
35extern "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
42namespace safestack {
43
44#if SANITIZER_NETBSD
45static 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
66using ThreadId = uint64_t;
67
68inline 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
81inline 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
93inline 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
104inline 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
113inline 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
125