xref: /freebsd/contrib/llvm-project/compiler-rt/lib/rtsan/rtsan_context.cpp (revision 7ab1a32cd43cbae61ad4dd435d6a482bbf61cb52)
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 
23 static pthread_key_t context_key;
24 static 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
28 static void InternalFreeWrapper(void *ptr) { __sanitizer::InternalFree(ptr); }
29 
30 static __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(&key_once, make_thread_local_context_key);
36   __rtsan::Context *current_thread_context =
37       static_cast<__rtsan::Context *>(pthread_getspecific(context_key));
38   if (current_thread_context == nullptr) {
39     current_thread_context = static_cast<__rtsan::Context *>(
40         __sanitizer::InternalAlloc(sizeof(__rtsan::Context)));
41     new (current_thread_context) __rtsan::Context();
42     pthread_setspecific(context_key, 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 */
62 static void InvokeViolationDetectedAction() { exit(EXIT_FAILURE); }
63 
64 __rtsan::Context::Context() = default;
65 
66 void __rtsan::Context::RealtimePush() { realtime_depth++; }
67 
68 void __rtsan::Context::RealtimePop() { realtime_depth--; }
69 
70 void __rtsan::Context::BypassPush() { bypass_depth++; }
71 
72 void __rtsan::Context::BypassPop() { bypass_depth--; }
73 
74 void __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 
84 bool __rtsan::Context::InRealtimeContext() const { return realtime_depth > 0; }
85 
86 bool __rtsan::Context::IsBypassed() const { return bypass_depth > 0; }
87 
88 void __rtsan::Context::PrintDiagnostics(const char *intercepted_function_name) {
89   fprintf(stderr,
90           "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