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// Copyright (c) 2010, Google Inc.
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived from
// this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
// Original author: Jim Blandy <jimb@mozilla.com> <jimb@red-bean.com>
// cfi_frame_info.cc: Implementation of CFIFrameInfo class.
// See cfi_frame_info.h for details.
#include <cstring>
#include "processor/cfi_frame_info.h"
#include "processor/postfix_evaluator-inl.h"
#include "processor/scoped_ptr.h"
namespace google_breakpad {
template<typename V>
bool CFIFrameInfo::FindCallerRegs(const RegisterValueMap<V> ®isters,
const MemoryRegion &memory,
RegisterValueMap<V> *caller_registers) const {
// If there are not rules for both .ra and .cfa in effect at this address,
// don't use this CFI data for stack walking.
if (cfa_rule_.empty() || ra_rule_.empty())
return false;
RegisterValueMap<V> working;
PostfixEvaluator<V> evaluator(&working, &memory);
caller_registers->clear();
// First, compute the CFA.
V cfa;
working = registers;
if (!evaluator.EvaluateForValue(cfa_rule_, &cfa))
return false;
// Then, compute the return address.
V ra;
working = registers;
working[".cfa"] = cfa;
if (!evaluator.EvaluateForValue(ra_rule_, &ra))
return false;
// Now, compute values for all the registers register_rules_ mentions.
for (RuleMap::const_iterator it = register_rules_.begin();
it != register_rules_.end(); it++) {
V value;
working = registers;
working[".cfa"] = cfa;
if (!evaluator.EvaluateForValue(it->second, &value))
return false;
(*caller_registers)[it->first] = value;
}
(*caller_registers)[".ra"] = ra;
(*caller_registers)[".cfa"] = cfa;
return true;
}
// Explicit instantiations for 32-bit and 64-bit architectures.
template bool CFIFrameInfo::FindCallerRegs<u_int32_t>(
const RegisterValueMap<u_int32_t> ®isters,
const MemoryRegion &memory,
RegisterValueMap<u_int32_t> *caller_registers) const;
template bool CFIFrameInfo::FindCallerRegs<u_int64_t>(
const RegisterValueMap<u_int64_t> ®isters,
const MemoryRegion &memory,
RegisterValueMap<u_int64_t> *caller_registers) const;
bool CFIRuleParser::Parse(const string &rule_set) {
size_t rule_set_len = rule_set.size();
scoped_array<char> working_copy(new char[rule_set_len + 1]);
memcpy(working_copy.get(), rule_set.data(), rule_set_len);
working_copy[rule_set_len] = '\0';
name_.clear();
expression_.clear();
char *cursor;
static const char token_breaks[] = " \t\r\n";
char *token = strtok_r(working_copy.get(), token_breaks, &cursor);
for (;;) {
// End of rule set?
if (!token) return Report();
// Register/pseudoregister name?
size_t token_len = strlen(token);
if (token_len >= 1 && token[token_len - 1] == ':') {
// Names can't be empty.
if (token_len < 2) return false;
// If there is any pending content, report it.
if (!name_.empty() || !expression_.empty()) {
if (!Report()) return false;
}
name_.assign(token, token_len - 1);
expression_.clear();
} else {
// Another expression component.
assert(token_len > 0); // strtok_r guarantees this, I think.
if (!expression_.empty())
expression_ += ' ';
expression_ += token;
}
token = strtok_r(NULL, token_breaks, &cursor);
}
}
bool CFIRuleParser::Report() {
if (name_.empty() || expression_.empty()) return false;
if (name_ == ".cfa") handler_->CFARule(expression_);
else if (name_ == ".ra") handler_->RARule(expression_);
else handler_->RegisterRule(name_, expression_);
return true;
}
void CFIFrameInfoParseHandler::CFARule(const string &expression) {
frame_info_->SetCFARule(expression);
}
void CFIFrameInfoParseHandler::RARule(const string &expression) {
frame_info_->SetRARule(expression);
}
void CFIFrameInfoParseHandler::RegisterRule(const string &name,
const string &expression) {
frame_info_->SetRegisterRule(name, expression);
}
} // namespace google_breakpad
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