libsanitizer/tsan/tsan_external.cpp

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