1 //===-- tsan_external.cc --------------------------------------------------===//
2 //
3 // This file is distributed under the University of Illinois Open Source
4 // License. See LICENSE.TXT for details.
5 //
6 //===----------------------------------------------------------------------===//
7 //
8 // This file is a part of ThreadSanitizer (TSan), a race detector.
9 //
10 //===----------------------------------------------------------------------===//
11 #include "tsan_rtl.h"
12 #include "tsan_interceptors.h"
13
14 namespace __tsan {
15
16 #define CALLERPC ((uptr)__builtin_return_address(0))
17
18 struct TagData {
19 const char *object_type;
20 const char *header;
21 };
22
23 static TagData registered_tags[kExternalTagMax] = {
24 {},
25 {"Swift variable", "Swift access race"},
26 };
27 static atomic_uint32_t used_tags{kExternalTagFirstUserAvailable}; // NOLINT.
GetTagData(uptr tag)28 static TagData *GetTagData(uptr tag) {
29 // Invalid/corrupted tag? Better return NULL and let the caller deal with it.
30 if (tag >= atomic_load(&used_tags, memory_order_relaxed)) return nullptr;
31 return ®istered_tags[tag];
32 }
33
GetObjectTypeFromTag(uptr tag)34 const char *GetObjectTypeFromTag(uptr tag) {
35 TagData *tag_data = GetTagData(tag);
36 return tag_data ? tag_data->object_type : nullptr;
37 }
38
GetReportHeaderFromTag(uptr tag)39 const char *GetReportHeaderFromTag(uptr tag) {
40 TagData *tag_data = GetTagData(tag);
41 return tag_data ? tag_data->header : nullptr;
42 }
43
InsertShadowStackFrameForTag(ThreadState * thr,uptr tag)44 void InsertShadowStackFrameForTag(ThreadState *thr, uptr tag) {
45 FuncEntry(thr, (uptr)®istered_tags[tag]);
46 }
47
TagFromShadowStackFrame(uptr pc)48 uptr TagFromShadowStackFrame(uptr pc) {
49 uptr tag_count = atomic_load(&used_tags, memory_order_relaxed);
50 void *pc_ptr = (void *)pc;
51 if (pc_ptr < GetTagData(0) || pc_ptr > GetTagData(tag_count - 1))
52 return 0;
53 return (TagData *)pc_ptr - GetTagData(0);
54 }
55
56 #if !SANITIZER_GO
57
58 typedef void(*AccessFunc)(ThreadState *, uptr, uptr, int);
ExternalAccess(void * addr,void * caller_pc,void * tag,AccessFunc access)59 void ExternalAccess(void *addr, void *caller_pc, void *tag, AccessFunc access) {
60 CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
61 ThreadState *thr = cur_thread();
62 if (caller_pc) FuncEntry(thr, (uptr)caller_pc);
63 InsertShadowStackFrameForTag(thr, (uptr)tag);
64 bool in_ignored_lib;
65 if (!caller_pc || !libignore()->IsIgnored((uptr)caller_pc, &in_ignored_lib)) {
66 access(thr, CALLERPC, (uptr)addr, kSizeLog1);
67 }
68 FuncExit(thr);
69 if (caller_pc) FuncExit(thr);
70 }
71
72 extern "C" {
73 SANITIZER_INTERFACE_ATTRIBUTE
__tsan_external_register_tag(const char * object_type)74 void *__tsan_external_register_tag(const char *object_type) {
75 uptr new_tag = atomic_fetch_add(&used_tags, 1, memory_order_relaxed);
76 CHECK_LT(new_tag, kExternalTagMax);
77 GetTagData(new_tag)->object_type = internal_strdup(object_type);
78 char header[127] = {0};
79 internal_snprintf(header, sizeof(header), "race on %s", object_type);
80 GetTagData(new_tag)->header = internal_strdup(header);
81 return (void *)new_tag;
82 }
83
84 SANITIZER_INTERFACE_ATTRIBUTE
__tsan_external_register_header(void * tag,const char * header)85 void __tsan_external_register_header(void *tag, const char *header) {
86 CHECK_GE((uptr)tag, kExternalTagFirstUserAvailable);
87 CHECK_LT((uptr)tag, kExternalTagMax);
88 atomic_uintptr_t *header_ptr =
89 (atomic_uintptr_t *)&GetTagData((uptr)tag)->header;
90 header = internal_strdup(header);
91 char *old_header =
92 (char *)atomic_exchange(header_ptr, (uptr)header, memory_order_seq_cst);
93 if (old_header) internal_free(old_header);
94 }
95
96 SANITIZER_INTERFACE_ATTRIBUTE
__tsan_external_assign_tag(void * addr,void * tag)97 void __tsan_external_assign_tag(void *addr, void *tag) {
98 CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed));
99 Allocator *a = allocator();
100 MBlock *b = nullptr;
101 if (a->PointerIsMine((void *)addr)) {
102 void *block_begin = a->GetBlockBegin((void *)addr);
103 if (block_begin) b = ctx->metamap.GetBlock((uptr)block_begin);
104 }
105 if (b) {
106 b->tag = (uptr)tag;
107 }
108 }
109
110 SANITIZER_INTERFACE_ATTRIBUTE
__tsan_external_read(void * addr,void * caller_pc,void * tag)111 void __tsan_external_read(void *addr, void *caller_pc, void *tag) {
112 ExternalAccess(addr, caller_pc, tag, MemoryRead);
113 }
114
115 SANITIZER_INTERFACE_ATTRIBUTE
__tsan_external_write(void * addr,void * caller_pc,void * tag)116 void __tsan_external_write(void *addr, void *caller_pc, void *tag) {
117 ExternalAccess(addr, caller_pc, tag, MemoryWrite);
118 }
119 } // extern "C"
120
121 #endif // !SANITIZER_GO
122
123 } // namespace __tsan
124