base/debug/crash_logging.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/debug/crash_logging.h"
   6
   7 #include <cmath>
   8 #include <map>
   9
  10 #include "base/debug/stack_trace.h"
  11 #include "base/format_macros.h"
  12 #include "base/logging.h"
  13 #include "base/string_util.h"
  14 #include "base/stringprintf.h"
  15
  16 namespace base {
  17 namespace debug {
  18
  19 namespace {
  20
  21 // Global map of crash key names to registration entries.
  22 typedef std::map<base::StringPiece, CrashKey> CrashKeyMap;
  23 CrashKeyMap* g_crash_keys_ = NULL;
  24
  25 // The maximum length of a single chunk.
  26 size_t g_chunk_max_length_ = 0;
  27
  28 // String used to format chunked key names.
  29 const char kChunkFormatString[] = "%s-%" PRIuS;
  30
  31 // The functions that are called to actually set the key-value pairs in the
  32 // crash reportng system.
  33 SetCrashKeyValueFuncT g_set_key_func_ = NULL;
  34 ClearCrashKeyValueFuncT g_clear_key_func_ = NULL;
  35
  36 // For a given |length|, computes the number of chunks a value of that size
  37 // will occupy.
  38 size_t NumChunksForLength(size_t length) {
  39   return std::ceil(length / static_cast<float>(g_chunk_max_length_));
  40 }
  41
  42 // The longest max_length allowed by the system.
  43 const size_t kLargestValueAllowed = 1024;
  44
  45 }  // namespace
  46
  47 void SetCrashKeyValue(const base::StringPiece& key,
  48                       const base::StringPiece& value) {
  49   if (!g_set_key_func_)
  50     return;
  51
  52   const CrashKey* crash_key = LookupCrashKey(key);
  53
  54   // TODO(rsesek): Do this:
  55   //DCHECK(crash_key) << "All crash keys must be registered before use "
  56   //                  << "(key = " << key << ")";
  57
  58   // Handle the un-chunked case.
  59   if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
  60     g_set_key_func_(key, value);
  61     return;
  62   }
  63
  64   // Unset the unused chunks.
  65   std::vector<std::string> chunks =
  66       ChunkCrashKeyValue(*crash_key, value, g_chunk_max_length_);
  67   for (size_t i = chunks.size();
  68        i < NumChunksForLength(crash_key->max_length);
  69        ++i) {
  70     g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
  71   }
  72
  73   // Set the chunked keys.
  74   for (size_t i = 0; i < chunks.size(); ++i) {
  75     g_set_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1),
  76                     chunks[i]);
  77   }
  78 }
  79
  80 void ClearCrashKey(const base::StringPiece& key) {
  81   if (!g_clear_key_func_)
  82     return;
  83
  84   const CrashKey* crash_key = LookupCrashKey(key);
  85
  86   // Handle the un-chunked case.
  87   if (!crash_key || crash_key->max_length <= g_chunk_max_length_) {
  88     g_clear_key_func_(key);
  89     return;
  90   }
  91
  92   for (size_t i = 0; i < NumChunksForLength(crash_key->max_length); ++i) {
  93     g_clear_key_func_(base::StringPrintf(kChunkFormatString, key.data(), i+1));
  94   }
  95 }
  96
  97 void SetCrashKeyToStackTrace(const base::StringPiece& key,
  98                              const StackTrace& trace) {
  99   size_t count = 0;
 100   const void* const* addresses = trace.Addresses(&count);
 101   SetCrashKeyFromAddresses(key, addresses, count);
 102 }
 103
 104 void SetCrashKeyFromAddresses(const base::StringPiece& key,
 105                               const void* const* addresses,
 106                               size_t count) {
 107   std::string value = "<null>";
 108   if (addresses && count) {
 109     const size_t kBreakpadValueMax = 255;
 110
 111     std::vector<std::string> hex_backtrace;
 112     size_t length = 0;
 113
 114     for (size_t i = 0; i < count; ++i) {
 115       std::string s = base::StringPrintf("%p", addresses[i]);
 116       length += s.length() + 1;
 117       if (length > kBreakpadValueMax)
 118         break;
 119       hex_backtrace.push_back(s);
 120     }
 121
 122     value = JoinString(hex_backtrace, ' ');
 123
 124     // Warn if this exceeds the breakpad limits.
 125     DCHECK_LE(value.length(), kBreakpadValueMax);
 126   }
 127
 128   SetCrashKeyValue(key, value);
 129 }
 130
 131 ScopedCrashKey::ScopedCrashKey(const base::StringPiece& key,
 132                                const base::StringPiece& value)
 133     : key_(key.as_string()) {
 134   SetCrashKeyValue(key, value);
 135 }
 136
 137 ScopedCrashKey::~ScopedCrashKey() {
 138   ClearCrashKey(key_);
 139 }
 140
 141 size_t InitCrashKeys(const CrashKey* const keys, size_t count,
 142                      size_t chunk_max_length) {
 143   DCHECK(!g_crash_keys_) << "Crash logging may only be initialized once";
 144   if (!keys) {
 145     delete g_crash_keys_;
 146     g_crash_keys_ = NULL;
 147     return 0;
 148   }
 149
 150   g_crash_keys_ = new CrashKeyMap;
 151   g_chunk_max_length_ = chunk_max_length;
 152
 153   size_t total_keys = 0;
 154   for (size_t i = 0; i < count; ++i) {
 155     g_crash_keys_->insert(std::make_pair(keys[i].key_name, keys[i]));
 156     total_keys += NumChunksForLength(keys[i].max_length);
 157     DCHECK_LT(keys[i].max_length, kLargestValueAllowed);
 158   }
 159   DCHECK_EQ(count, g_crash_keys_->size())
 160       << "Duplicate crash keys were registered";
 161
 162   return total_keys;
 163 }
 164
 165 const CrashKey* LookupCrashKey(const base::StringPiece& key) {
 166   CrashKeyMap::const_iterator it = g_crash_keys_->find(key.as_string());
 167   if (it == g_crash_keys_->end())
 168     return NULL;
 169   return &(it->second);
 170 }
 171
 172 void SetCrashKeyReportingFunctions(
 173     SetCrashKeyValueFuncT set_key_func,
 174     ClearCrashKeyValueFuncT clear_key_func) {
 175   g_set_key_func_ = set_key_func;
 176   g_clear_key_func_ = clear_key_func;
 177 }
 178
 179 std::vector<std::string> ChunkCrashKeyValue(const CrashKey& crash_key,
 180                                             const base::StringPiece& value,
 181                                             size_t chunk_max_length) {
 182   std::string value_string = value.substr(0, crash_key.max_length).as_string();
 183   std::vector<std::string> chunks;
 184   for (size_t offset = 0; offset < value_string.length(); ) {
 185     std::string chunk = value_string.substr(offset, chunk_max_length);
 186     chunks.push_back(chunk);
 187     offset += chunk.length();
 188   }
 189   return chunks;
 190 }
 191
 192 void ResetCrashLoggingForTesting() {
 193   delete g_crash_keys_;
 194   g_crash_keys_ = NULL;
 195   g_chunk_max_length_ = 0;
 196   g_set_key_func_ = NULL;
 197   g_clear_key_func_ = NULL;
 198 }
 199
 200 }  // namespace debug
 201 }  // namespace base