1//===--- rtsan_context.cpp - Realtime Sanitizer -----------------*- 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//===----------------------------------------------------------------------===//
10
11#include <rtsan/rtsan_context.h>
12
13#include <rtsan/rtsan_stack.h>
14
15#include <sanitizer_common/sanitizer_allocator_internal.h>
16#include <sanitizer_common/sanitizer_stacktrace.h>
17
18#include <new>
19#include <pthread.h>
20#include <stdio.h>
21#include <stdlib.h>
22
23static pthread_key_t context_key;
24static pthread_once_t key_once = PTHREAD_ONCE_INIT;
25
26// InternalFree cannot be passed directly to pthread_key_create
27// because it expects a signature with only one arg
28static void InternalFreeWrapper(void *ptr) { __sanitizer::InternalFree(p: ptr); }
29
30static __rtsan::Context &GetContextForThisThreadImpl() {
31 auto make_thread_local_context_key = []() {
32 CHECK_EQ(pthread_key_create(&context_key, InternalFreeWrapper), 0);
33 };
34
35 pthread_once(once_control: &key_once, init_routine: make_thread_local_context_key);
36 __rtsan::Context *current_thread_context =
37 static_cast<__rtsan::Context *>(pthread_getspecific(key: context_key));
38 if (current_thread_context == nullptr) {
39 current_thread_context = static_cast<__rtsan::Context *>(
40 __sanitizer::InternalAlloc(size: sizeof(__rtsan::Context)));
41 new (current_thread_context) __rtsan::Context();
42 pthread_setspecific(key: context_key, pointer: current_thread_context);
43 }
44
45 return *current_thread_context;
46}
47
48/*
49 This is a placeholder stub for a future feature that will allow
50 a user to configure RTSan's behaviour when a real-time safety
51 violation is detected. The RTSan developers intend for the
52 following choices to be made available, via a RTSAN_OPTIONS
53 environment variable, in a future PR:
54
55 i) exit,
56 ii) continue, or
57 iii) wait for user input from stdin.
58
59 Until then, and to keep the first PRs small, only the exit mode
60 is available.
61*/
62static void InvokeViolationDetectedAction() { exit(EXIT_FAILURE); }
63
64__rtsan::Context::Context() = default;
65
66void __rtsan::Context::RealtimePush() { realtime_depth++; }
67
68void __rtsan::Context::RealtimePop() { realtime_depth--; }
69
70void __rtsan::Context::BypassPush() { bypass_depth++; }
71
72void __rtsan::Context::BypassPop() { bypass_depth--; }
73
74void __rtsan::Context::ExpectNotRealtime(
75 const char *intercepted_function_name) {
76 if (InRealtimeContext() && !IsBypassed()) {
77 BypassPush();
78 PrintDiagnostics(intercepted_function_name);
79 InvokeViolationDetectedAction();
80 BypassPop();
81 }
82}
83
84bool __rtsan::Context::InRealtimeContext() const { return realtime_depth > 0; }
85
86bool __rtsan::Context::IsBypassed() const { return bypass_depth > 0; }
87
88void __rtsan::Context::PrintDiagnostics(const char *intercepted_function_name) {
89 fprintf(stderr,
90 format: "Real-time violation: intercepted call to real-time unsafe function "
91 "`%s` in real-time context! Stack trace:\n",
92 intercepted_function_name);
93 __rtsan::PrintStackTrace();
94}
95
96__rtsan::Context &__rtsan::GetContextForThisThread() {
97 return GetContextForThisThreadImpl();
98}
99