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_stacktrace_printer.h"
  26 #  include "sanitizer_symbolizer.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 mainly used by hwasan for online symbolization. This isn't needed
  58 // since hwasan can always just dump stack frames for offline symbolization.
  59 bool Symbolizer::SymbolizeFrame(uptr addr, FrameInfo *info) { return false; }
  60
  61 // This is used in some places for suppression checking, which we
  62 // don't really support for Fuchsia.  It's also used in UBSan to
  63 // identify a PC location to a function name, so we always fill in
  64 // the function member with a string containing markup around the PC
  65 // value.
  66 // TODO(mcgrathr): Under SANITIZER_GO, it's currently used by TSan
  67 // to render stack frames, but that should be changed to use
  68 // RenderStackFrame.
  69 SymbolizedStack *Symbolizer::SymbolizePC(uptr addr) {
  70   SymbolizedStack *s = SymbolizedStack::New(addr);
  71   char buffer[kFormatFunctionMax];
  72   internal_snprintf(buffer, sizeof(buffer), kFormatFunction, addr);
  73   s->info.function = internal_strdup(buffer);
  74   return s;
  75 }
  76
  77 // Always claim we succeeded, so that RenderDataInfo will be called.
  78 bool Symbolizer::SymbolizeData(uptr addr, DataInfo *info) {
  79   info->Clear();
  80   info->start = addr;
  81   return true;
  82 }
  83
  84 // We ignore the format argument to __sanitizer_symbolize_global.
  85 void FormattedStackTracePrinter::RenderData(InternalScopedString *buffer,
  86                                             const char *format,
  87                                             const DataInfo *DI,
  88                                             const char *strip_path_prefix) {
  89   buffer->AppendF(kFormatData, DI->start);
  90 }
  91
  92 bool FormattedStackTracePrinter::RenderNeedsSymbolization(const char *format) {
  93   return false;
  94 }
  95
  96 // We don't support the stack_trace_format flag at all.
  97 void FormattedStackTracePrinter::RenderFrame(InternalScopedString *buffer,
  98                                              const char *format, int frame_no,
  99                                              uptr address,
 100                                              const AddressInfo *info,
 101                                              bool vs_style,
 102                                              const char *strip_path_prefix) {
 103   CHECK(!RenderNeedsSymbolization(format));
 104   buffer->AppendF(kFormatFrame, frame_no, address);
 105 }
 106
 107 Symbolizer *Symbolizer::PlatformInit() {
 108   return new (symbolizer_allocator_) Symbolizer({});
 109 }
 110
 111 void Symbolizer::LateInitialize() { Symbolizer::GetOrInit(); }
 112
 113 void StartReportDeadlySignal() {}
 114 void ReportDeadlySignal(const SignalContext &sig, u32 tid,
 115                         UnwindSignalStackCallbackType unwind,
 116                         const void *unwind_context) {}
 117
 118 #if SANITIZER_CAN_SLOW_UNWIND
 119 struct UnwindTraceArg {
 120   BufferedStackTrace *stack;
 121   u32 max_depth;
 122 };
 123
 124 _Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
 125   UnwindTraceArg *arg = static_cast<UnwindTraceArg *>(param);
 126   CHECK_LT(arg->stack->size, arg->max_depth);
 127   uptr pc = _Unwind_GetIP(ctx);
 128   if (pc < PAGE_SIZE) return _URC_NORMAL_STOP;
 129   arg->stack->trace_buffer[arg->stack->size++] = pc;
 130   return (arg->stack->size == arg->max_depth ? _URC_NORMAL_STOP
 131                                              : _URC_NO_REASON);
 132 }
 133
 134 void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
 135   CHECK_GE(max_depth, 2);
 136   size = 0;
 137   UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
 138   _Unwind_Backtrace(Unwind_Trace, &arg);
 139   CHECK_GT(size, 0);
 140   // We need to pop a few frames so that pc is on top.
 141   uptr to_pop = LocatePcInTrace(pc);
 142   // trace_buffer[0] belongs to the current function so we always pop it,
 143   // unless there is only 1 frame in the stack trace (1 frame is always better
 144   // than 0!).
 145   PopStackFrames(Min(to_pop, static_cast<uptr>(1)));
 146   trace_buffer[0] = pc;
 147 }
 148
 149 void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
 150   CHECK(context);
 151   CHECK_GE(max_depth, 2);
 152   UNREACHABLE("signal context doesn't exist");
 153 }
 154 #endif  // SANITIZER_CAN_SLOW_UNWIND
 155
 156 }  // namespace __sanitizer
 157
 158 #endif  // SANITIZER_SYMBOLIZER_MARKUP