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
GetRealLibcAddress(const char * symbol)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
GetTid()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
TgKill(pid_t pid,ThreadId tid,int sig)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
Mmap(void * addr,size_t length,int prot,int flags,int fd,off_t offset)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
Munmap(void * addr,size_t length)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
Mprotect(void * addr,size_t length,int prot)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
125