1// Copyright (c) 2010, Google Inc. 2// All rights reserved. 3// 4// Redistribution and use in source and binary forms, with or without 5// modification, are permitted provided that the following conditions are 6// met: 7// 8// * Redistributions of source code must retain the above copyright 9// notice, this list of conditions and the following disclaimer. 10// * Redistributions in binary form must reproduce the above 11// copyright notice, this list of conditions and the following disclaimer 12// in the documentation and/or other materials provided with the 13// distribution. 14// * Neither the name of Google Inc. nor the names of its 15// contributors may be used to endorse or promote products derived from 16// this software without specific prior written permission. 17// 18// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 19// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 20// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 21// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 22// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 23// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 24// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 25// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 26// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 27// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 28// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 30// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com> 31 32// cfi_frame_info.cc: Implementation of CFIFrameInfo class. 33// See cfi_frame_info.h for details. 34 35#include "processor/cfi_frame_info.h" 36 37#include <string.h> 38 39#include <sstream> 40 41#include "common/scoped_ptr.h" 42#include "processor/postfix_evaluator-inl.h" 43 44namespace google_breakpad { 45 46#ifdef _WIN32 47#define strtok_r strtok_s 48#endif 49 50template<typename V> 51bool CFIFrameInfo::FindCallerRegs(const RegisterValueMap<V> ®isters, 52 const MemoryRegion &memory, 53 RegisterValueMap<V> *caller_registers) const { 54 // If there are not rules for both .ra and .cfa in effect at this address, 55 // don't use this CFI data for stack walking. 56 if (cfa_rule_.empty() || ra_rule_.empty()) 57 return false; 58 59 RegisterValueMap<V> working; 60 PostfixEvaluator<V> evaluator(&working, &memory); 61 62 caller_registers->clear(); 63 64 // First, compute the CFA. 65 V cfa; 66 working = registers; 67 if (!evaluator.EvaluateForValue(cfa_rule_, &cfa)) 68 return false; 69 70 // Then, compute the return address. 71 V ra; 72 working = registers; 73 working[".cfa"] = cfa; 74 if (!evaluator.EvaluateForValue(ra_rule_, &ra)) 75 return false; 76 77 // Now, compute values for all the registers register_rules_ mentions. 78 for (RuleMap::const_iterator it = register_rules_.begin(); 79 it != register_rules_.end(); it++) { 80 V value; 81 working = registers; 82 working[".cfa"] = cfa; 83 if (!evaluator.EvaluateForValue(it->second, &value)) 84 return false; 85 (*caller_registers)[it->first] = value; 86 } 87 88 (*caller_registers)[".ra"] = ra; 89 (*caller_registers)[".cfa"] = cfa; 90 91 return true; 92} 93 94// Explicit instantiations for 32-bit and 64-bit architectures. 95template bool CFIFrameInfo::FindCallerRegs<uint32_t>( 96 const RegisterValueMap<uint32_t> ®isters, 97 const MemoryRegion &memory, 98 RegisterValueMap<uint32_t> *caller_registers) const; 99template bool CFIFrameInfo::FindCallerRegs<uint64_t>( 100 const RegisterValueMap<uint64_t> ®isters, 101 const MemoryRegion &memory, 102 RegisterValueMap<uint64_t> *caller_registers) const; 103 104string CFIFrameInfo::Serialize() const { 105 std::ostringstream stream; 106 107 if (!cfa_rule_.empty()) { 108 stream << ".cfa: " << cfa_rule_; 109 } 110 if (!ra_rule_.empty()) { 111 if (static_cast<std::streamoff>(stream.tellp()) != 0) 112 stream << " "; 113 stream << ".ra: " << ra_rule_; 114 } 115 for (RuleMap::const_iterator iter = register_rules_.begin(); 116 iter != register_rules_.end(); 117 ++iter) { 118 if (static_cast<std::streamoff>(stream.tellp()) != 0) 119 stream << " "; 120 stream << iter->first << ": " << iter->second; 121 } 122 123 return stream.str(); 124} 125 126bool CFIRuleParser::Parse(const string &rule_set) { 127 size_t rule_set_len = rule_set.size(); 128 scoped_array<char> working_copy(new char[rule_set_len + 1]); 129 memcpy(working_copy.get(), rule_set.data(), rule_set_len); 130 working_copy[rule_set_len] = '\0'; 131 132 name_.clear(); 133 expression_.clear(); 134 135 char *cursor; 136 static const char token_breaks[] = " \t\r\n"; 137 char *token = strtok_r(working_copy.get(), token_breaks, &cursor); 138 139 for (;;) { 140 // End of rule set? 141 if (!token) return Report(); 142 143 // Register/pseudoregister name? 144 size_t token_len = strlen(token); 145 if (token_len >= 1 && token[token_len - 1] == ':') { 146 // Names can't be empty. 147 if (token_len < 2) return false; 148 // If there is any pending content, report it. 149 if (!name_.empty() || !expression_.empty()) { 150 if (!Report()) return false; 151 } 152 name_.assign(token, token_len - 1); 153 expression_.clear(); 154 } else { 155 // Another expression component. 156 assert(token_len > 0); // strtok_r guarantees this, I think. 157 if (!expression_.empty()) 158 expression_ += ' '; 159 expression_ += token; 160 } 161 token = strtok_r(NULL, token_breaks, &cursor); 162 } 163} 164 165bool CFIRuleParser::Report() { 166 if (name_.empty() || expression_.empty()) return false; 167 if (name_ == ".cfa") handler_->CFARule(expression_); 168 else if (name_ == ".ra") handler_->RARule(expression_); 169 else handler_->RegisterRule(name_, expression_); 170 return true; 171} 172 173void CFIFrameInfoParseHandler::CFARule(const string &expression) { 174 frame_info_->SetCFARule(expression); 175} 176 177void CFIFrameInfoParseHandler::RARule(const string &expression) { 178 frame_info_->SetRARule(expression); 179} 180 181void CFIFrameInfoParseHandler::RegisterRule(const string &name, 182 const string &expression) { 183 frame_info_->SetRegisterRule(name, expression); 184} 185 186} // namespace google_breakpad 187