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
27namespace __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.
40const 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.
51bool 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.
58bool 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.
68SymbolizedStack *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.
77bool 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.
84void RenderData(InternalScopedString *buffer, const char *format,
85                const DataInfo *DI, const char *strip_path_prefix) {
86  buffer->append(kFormatData, DI->start);
87}
88
89bool RenderNeedsSymbolization(const char *format) { return false; }
90
91// We don't support the stack_trace_format flag at all.
92void 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
99Symbolizer *Symbolizer::PlatformInit() {
100  return new (symbolizer_allocator_) Symbolizer({});
101}
102
103void Symbolizer::LateInitialize() { Symbolizer::GetOrInit(); }
104
105void StartReportDeadlySignal() {}
106void ReportDeadlySignal(const SignalContext &sig, u32 tid,
107                        UnwindSignalStackCallbackType unwind,
108                        const void *unwind_context) {}
109
110#if SANITIZER_CAN_SLOW_UNWIND
111struct UnwindTraceArg {
112  BufferedStackTrace *stack;
113  u32 max_depth;
114};
115
116_Unwind_Reason_Code Unwind_Trace(struct _Unwind_Context *ctx, void *param) {
117  UnwindTraceArg *arg = static_cast<UnwindTraceArg *>(param);
118  CHECK_LT(arg->stack->size, arg->max_depth);
119  uptr pc = _Unwind_GetIP(ctx);
120  if (pc < PAGE_SIZE) return _URC_NORMAL_STOP;
121  arg->stack->trace_buffer[arg->stack->size++] = pc;
122  return (arg->stack->size == arg->max_depth ? _URC_NORMAL_STOP
123                                             : _URC_NO_REASON);
124}
125
126void BufferedStackTrace::UnwindSlow(uptr pc, u32 max_depth) {
127  CHECK_GE(max_depth, 2);
128  size = 0;
129  UnwindTraceArg arg = {this, Min(max_depth + 1, kStackTraceMax)};
130  _Unwind_Backtrace(Unwind_Trace, &arg);
131  CHECK_GT(size, 0);
132  // We need to pop a few frames so that pc is on top.
133  uptr to_pop = LocatePcInTrace(pc);
134  // trace_buffer[0] belongs to the current function so we always pop it,
135  // unless there is only 1 frame in the stack trace (1 frame is always better
136  // than 0!).
137  PopStackFrames(Min(to_pop, static_cast<uptr>(1)));
138  trace_buffer[0] = pc;
139}
140
141void BufferedStackTrace::UnwindSlow(uptr pc, void *context, u32 max_depth) {
142  CHECK(context);
143  CHECK_GE(max_depth, 2);
144  UNREACHABLE("signal context doesn't exist");
145}
146#endif  // SANITIZER_CAN_SLOW_UNWIND
147
148}  // namespace __sanitizer
149
150#endif  // SANITIZER_SYMBOLIZER_MARKUP
151