1 //===-- tsan_external.cpp -------------------------------------------------===// 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 is a part of ThreadSanitizer (TSan), a race detector. 10 // 11 //===----------------------------------------------------------------------===// 12 #include "tsan_rtl.h" 13 #include "tsan_interceptors.h" 14 #include "sanitizer_common/sanitizer_ptrauth.h" 15 16 namespace __tsan { 17 18 #define CALLERPC ((uptr)__builtin_return_address(0)) 19 20 struct TagData { 21 const char *object_type; 22 const char *header; 23 }; 24 25 static TagData registered_tags[kExternalTagMax] = { 26 {}, 27 {"Swift variable", "Swift access race"}, 28 }; 29 static atomic_uint32_t used_tags{kExternalTagFirstUserAvailable}; 30 static TagData *GetTagData(uptr tag) { 31 // Invalid/corrupted tag? Better return NULL and let the caller deal with it. 32 if (tag >= atomic_load(&used_tags, memory_order_relaxed)) return nullptr; 33 return ®istered_tags[tag]; 34 } 35 36 const char *GetObjectTypeFromTag(uptr tag) { 37 TagData *tag_data = GetTagData(tag); 38 return tag_data ? tag_data->object_type : nullptr; 39 } 40 41 const char *GetReportHeaderFromTag(uptr tag) { 42 TagData *tag_data = GetTagData(tag); 43 return tag_data ? tag_data->header : nullptr; 44 } 45 46 void InsertShadowStackFrameForTag(ThreadState *thr, uptr tag) { 47 FuncEntry(thr, (uptr)®istered_tags[tag]); 48 } 49 50 uptr TagFromShadowStackFrame(uptr pc) { 51 uptr tag_count = atomic_load(&used_tags, memory_order_relaxed); 52 void *pc_ptr = (void *)pc; 53 if (pc_ptr < GetTagData(0) || pc_ptr > GetTagData(tag_count - 1)) 54 return 0; 55 return (TagData *)pc_ptr - GetTagData(0); 56 } 57 58 #if !SANITIZER_GO 59 60 typedef void(*AccessFunc)(ThreadState *, uptr, uptr, int); 61 void ExternalAccess(void *addr, uptr caller_pc, void *tag, AccessFunc access) { 62 CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed)); 63 ThreadState *thr = cur_thread(); 64 if (caller_pc) FuncEntry(thr, caller_pc); 65 InsertShadowStackFrameForTag(thr, (uptr)tag); 66 bool in_ignored_lib; 67 if (!caller_pc || !libignore()->IsIgnored(caller_pc, &in_ignored_lib)) { 68 access(thr, CALLERPC, (uptr)addr, kSizeLog1); 69 } 70 FuncExit(thr); 71 if (caller_pc) FuncExit(thr); 72 } 73 74 extern "C" { 75 SANITIZER_INTERFACE_ATTRIBUTE 76 void *__tsan_external_register_tag(const char *object_type) { 77 uptr new_tag = atomic_fetch_add(&used_tags, 1, memory_order_relaxed); 78 CHECK_LT(new_tag, kExternalTagMax); 79 GetTagData(new_tag)->object_type = internal_strdup(object_type); 80 char header[127] = {0}; 81 internal_snprintf(header, sizeof(header), "race on %s", object_type); 82 GetTagData(new_tag)->header = internal_strdup(header); 83 return (void *)new_tag; 84 } 85 86 SANITIZER_INTERFACE_ATTRIBUTE 87 void __tsan_external_register_header(void *tag, const char *header) { 88 CHECK_GE((uptr)tag, kExternalTagFirstUserAvailable); 89 CHECK_LT((uptr)tag, kExternalTagMax); 90 atomic_uintptr_t *header_ptr = 91 (atomic_uintptr_t *)&GetTagData((uptr)tag)->header; 92 header = internal_strdup(header); 93 char *old_header = 94 (char *)atomic_exchange(header_ptr, (uptr)header, memory_order_seq_cst); 95 if (old_header) internal_free(old_header); 96 } 97 98 SANITIZER_INTERFACE_ATTRIBUTE 99 void __tsan_external_assign_tag(void *addr, void *tag) { 100 CHECK_LT(tag, atomic_load(&used_tags, memory_order_relaxed)); 101 Allocator *a = allocator(); 102 MBlock *b = nullptr; 103 if (a->PointerIsMine((void *)addr)) { 104 void *block_begin = a->GetBlockBegin((void *)addr); 105 if (block_begin) b = ctx->metamap.GetBlock((uptr)block_begin); 106 } 107 if (b) { 108 b->tag = (uptr)tag; 109 } 110 } 111 112 SANITIZER_INTERFACE_ATTRIBUTE 113 void __tsan_external_read(void *addr, void *caller_pc, void *tag) { 114 ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, MemoryRead); 115 } 116 117 SANITIZER_INTERFACE_ATTRIBUTE 118 void __tsan_external_write(void *addr, void *caller_pc, void *tag) { 119 ExternalAccess(addr, STRIP_PAC_PC(caller_pc), tag, MemoryWrite); 120 } 121 } // extern "C" 122 123 #endif // !SANITIZER_GO 124 125 } // namespace __tsan 126