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