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 (at) mozilla.com> <jimb (at) 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 44 namespace google_breakpad { 45 46 #ifdef _WIN32 47 #define strtok_r strtok_s 48 #endif 49 50 template<typename V> 51 bool 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. 95 template bool CFIFrameInfo::FindCallerRegs<uint32_t>( 96 const RegisterValueMap<uint32_t> ®isters, 97 const MemoryRegion &memory, 98 RegisterValueMap<uint32_t> *caller_registers) const; 99 template bool CFIFrameInfo::FindCallerRegs<uint64_t>( 100 const RegisterValueMap<uint64_t> ®isters, 101 const MemoryRegion &memory, 102 RegisterValueMap<uint64_t> *caller_registers) const; 103 104 string 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 } 125 126 bool 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 } 164 165 bool 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 } 172 173 void CFIFrameInfoParseHandler::CFARule(const string &expression) { 174 frame_info_->SetCFARule(expression); 175 } 176 177 void CFIFrameInfoParseHandler::RARule(const string &expression) { 178 frame_info_->SetRARule(expression); 179 } 180 181 void CFIFrameInfoParseHandler::RegisterRule(const string &name, 182 const string &expression) { 183 frame_info_->SetRegisterRule(name, expression); 184 } 185 186 } // namespace google_breakpad 187
