libsanitizer/sanitizer_common/sanitizer_symbolizer_markup.cpp

   1 //===-- sanitizer_symbolizer_markup.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 shared between various sanitizers' runtime libraries.
  10 //
  11 // Implementation of offline markup symbolizer.
  12 //===----------------------------------------------------------------------===//
  13
  14 #include "sanitizer_platform.h"
  15 #if SANITIZER_SYMBOLIZER_MARKUP
  16
  17 #if SANITIZER_FUCHSIA
  18 #include "sanitizer_symbolizer_fuchsia.h"
  19 #  endif
  20
  21 #  include <limits.h>
  22 #  include <unwind.h>
  23
  24 #  include "sanitizer_stacktrace.h"
  25 #  include "sanitizer_symbolizer.h"
  26
  27 namespace __sanitizer {
  28
  29 // This generic support for offline symbolizing is based on the
  30 // Fuchsia port.  We don't do any actual symbolization per se.
  31 // Instead, we emit text containing raw addresses and raw linkage
  32 // symbol names, embedded in Fuchsia's symbolization markup format.
  33 // Fuchsia's logging infrastructure emits enough information about
  34 // process memory layout that a post-processing filter can do the
  35 // symbolization and pretty-print the markup.  See the spec at:
  36 // https://fuchsia.googlesource.com/zircon/+/master/docs/symbolizer_markup.md
  37
  38 // This is used by UBSan for type names, and by ASan for global variable names.
  39 // It's expected to return a static buffer that will be reused on each call.
  40 const char *Symbolizer::Demangle(const char *name) {
  41   static char buffer[kFormatDemangleMax];
  42   internal_snprintf(buffer, sizeof(buffer), kFormatDemangle, name);
  43   return buffer;
  44 }
  45
  46 // This is used mostly for suppression matching.  Making it work
  47 // would enable "interceptor_via_lib" suppressions.  It's also used
  48 // once in UBSan to say "in module ..." in a message that also
  49 // includes an address in the module, so post-processing can already
  50 // pretty-print that so as to indicate the module.
  51 bool Symbolizer::GetModuleNameAndOffsetForPC(uptr pc, const char **module_name,
  52                                              uptr *module_address) {
  53   return false;
  54 }
  55
  56 // This is mainly used by hwasan for online symbolization. This isn't needed
  57 // since hwasan can always just dump stack frames for offline symbolization.
  58 bool Symbolizer::SymbolizeFrame(uptr addr, FrameInfo *info) { return false; }
  59
  60 // This is used in some places for suppression checking, which we
  61 // don't really support for Fuchsia.  It's also used in UBSan to
  62 // identify a PC location to a function name, so we always fill in
  63 // the function member with a string containing markup around the PC
  64 // value.
  65 // TODO(mcgrathr): Under SANITIZER_GO, it's currently used by TSan
  66 // to render stack frames, but that should be changed to use
  67 // RenderStackFrame.
  68 SymbolizedStack *Symbolizer::SymbolizePC(uptr addr) {
  69   SymbolizedStack *s = SymbolizedStack::New(addr);
  70   char buffer[kFormatFunctionMax];
  71   internal_snprintf(buffer, sizeof(buffer), kFormatFunction, addr);
  72   s->info.function = internal_strdup(buffer);
  73   return s;
  74 }
  75
  76 // Always claim we succeeded, so that RenderDataInfo will be called.
  77 bool Symbolizer::SymbolizeData(uptr addr, DataInfo *info) {
  78   info->Clear();
  79   info->start = addr;
  80   return true;
  81 }
  82
  83 // We ignore the format argument to __sanitizer_symbolize_global.
  84 void RenderData(InternalScopedString *buffer, const char *format,
  85                 const DataInfo *DI, const char *strip_path_prefix) {
  86   buffer->append(kFormatData, DI->start);
  87 }
  88
  89 bool RenderNeedsSymbolization(const char *format) { return false; }
  90
  91 // We don't support the stack_trace_format flag at all.
  92 void RenderFrame(InternalScopedString *buffer, const char *format, int frame_no,
  93                  uptr address, const AddressInfo *info, bool vs_style,
  94                  const char *strip_path_prefix, const char *strip_func_prefix) {
  95   CHECK(!RenderNeedsSymbolization(format));
  96   buffer->append(kFormatFrame, frame_no, address);
  97 }
  98
  99 Symbolizer *Symbolizer::PlatformInit() {
 100   return new (symbolizer_allocator_) Symbolizer({});
 101 }
 102
 103 void Symbolizer::LateInitialize() {
 104   Symbolizer::GetOrInit()->LateInitializeTools();
 105 }
 106
 107 void StartReportDeadlySignal() {}
 108 void ReportDeadlySignal(const SignalContext &sig, u32 tid,
 109                         UnwindSignalStackCallbackType unwind,
 110                         const void *unwind_context) {}
 111
 112 #if SANITIZER_CAN_SLOW_UNWIND
 113 struct UnwindTraceArg {
 114   BufferedStackTrace *stack;
 115   u32 max_depth;
 116 };
 117
 118 _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
 119   UnwindTraceArg *arg = static_cast<UnwindTraceArg *>(param);
 120   CHECK_LT(arg->stack->size, arg->max_depth);
 121   uptr pc = _Unwind_GetIP(ctx);
 122   if (pc < PAGE_SIZE) return _URC_NORMAL_STOP;
 123   arg->stack->trace_buffer[arg->stack->size++] = pc;
 124   return (arg->stack->size == arg->max_depth ? _URC_NORMAL_STOP
 125                                              : _URC_NO_REASON);
 126 }
 127
 128 void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
 129   CHECK_GE(max_depth, 2);
 130   size = 0;
 131   UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
 132   _Unwind_Backtrace(Unwind_Trace, &arg);
 133   CHECK_GT(size, 0);
 134   // We need to pop a few frames so that pc is on top.
 135   uptr to_pop = LocatePcInTrace(pc);
 136   // trace_buffer[0] belongs to the current function so we always pop it,
 137   // unless there is only 1 frame in the stack trace (1 frame is always better
 138   // than 0!).
 139   PopStackFrames(Min(to_pop, static_cast<uptr>(1)));
 140   trace_buffer[0] = pc;
 141 }
 142
 143 void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
 144   CHECK(context);
 145   CHECK_GE(max_depth, 2);
 146   UNREACHABLE("signal context doesn't exist");
 147 }
 148 #endif  // SANITIZER_CAN_SLOW_UNWIND
 149
 150 }  // namespace __sanitizer
 151
 152 #endif  // SANITIZER_SYMBOLIZER_MARKUP