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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2015 Daniel Marjamäki and Cppcheck team.
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
//---------------------------------------------------------------------------
// Leaks when using auto variables
//---------------------------------------------------------------------------
#include "checkleakautovar.h"
#include "checkmemoryleak.h" // <- CheckMemoryLeak::memoryLeak
#include "tokenize.h"
#include "symboldatabase.h"
#include <iostream>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckLeakAutoVar instance;
}
//---------------------------------------------------------------------------
void VarInfo::print()
{
std::cout << "size=" << alloctype.size() << std::endl;
std::map<unsigned int, AllocInfo>::const_iterator it;
for (it = alloctype.begin(); it != alloctype.end(); ++it) {
std::string strusage;
std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(it->first);
if (use != possibleUsage.end())
strusage = use->second;
std::cout << "alloctype='" << it->second.type << "' "
<< "possibleUsage='" << strusage << "'" << std::endl;
}
}
void VarInfo::possibleUsageAll(const std::string &functionName)
{
possibleUsage.clear();
std::map<unsigned int, AllocInfo>::const_iterator it;
for (it = alloctype.begin(); it != alloctype.end(); ++it)
possibleUsage[it->first] = functionName;
}
void CheckLeakAutoVar::leakError(const Token *tok, const std::string &varname, int type)
{
const CheckMemoryLeak checkmemleak(_tokenizer, _errorLogger, _settings);
if (_settings->library.isresource(type))
checkmemleak.resourceLeakError(tok, varname);
else
checkmemleak.memleakError(tok, varname);
}
void CheckLeakAutoVar::mismatchError(const Token *tok, const std::string &varname)
{
const CheckMemoryLeak c(_tokenizer, _errorLogger, _settings);
std::list<const Token *> callstack(1, tok);
c.mismatchAllocDealloc(callstack, varname);
}
void CheckLeakAutoVar::deallocUseError(const Token *tok, const std::string &varname)
{
const CheckMemoryLeak c(_tokenizer, _errorLogger, _settings);
c.deallocuseError(tok, varname);
}
void CheckLeakAutoVar::deallocReturnError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "deallocret", "Returning/dereferencing '" + varname + "' after it is deallocated / released");
}
void CheckLeakAutoVar::configurationInfo(const Token* tok, const std::string &functionName)
{
if (_settings->checkLibrary && _settings->isEnabled("information")) {
reportError(tok,
Severity::information,
"checkLibraryUseIgnore",
"--check-library: Function " + functionName + "() should have <use>/<leak-ignore> configuration");
}
}
void CheckLeakAutoVar::doubleFreeError(const Token *tok, const std::string &varname, int type)
{
if (_settings->library.isresource(type))
reportError(tok, Severity::error, "doubleFree", "Resource handle '" + varname + "' freed twice.");
else
reportError(tok, Severity::error, "doubleFree", "Memory pointed to by '" + varname + "' is freed twice.");
}
void CheckLeakAutoVar::check()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
// Local variables that are known to be non-zero.
const std::set<unsigned int> notzero;
// Check function scopes
const std::size_t functions = symbolDatabase->functionScopes.size();
for (std::size_t i = 0; i < functions; ++i) {
const Scope * scope = symbolDatabase->functionScopes[i];
// Empty variable info
VarInfo varInfo;
checkScope(scope->classStart, &varInfo, notzero);
varInfo.conditionalAlloc.clear();
// Clear reference arguments from varInfo..
std::map<unsigned int, VarInfo::AllocInfo>::iterator it = varInfo.alloctype.begin();
while (it != varInfo.alloctype.end()) {
const Variable *var = symbolDatabase->getVariableFromVarId(it->first);
if (!var ||
(var->isArgument() && var->isReference()) ||
(!var->isArgument() && !var->isLocal()))
varInfo.alloctype.erase(it++);
else
++it;
}
ret(scope->classEnd, varInfo);
}
}
void CheckLeakAutoVar::checkScope(const Token * const startToken,
VarInfo *varInfo,
std::set<unsigned int> notzero)
{
std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo->alloctype;
std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
const std::set<unsigned int> conditionalAlloc(varInfo->conditionalAlloc);
// Parse all tokens
const Token * const endToken = startToken->link();
for (const Token *tok = startToken; tok && tok != endToken; tok = tok->next()) {
if (!tok->scope()->isExecutable()) {
tok = tok->scope()->classEnd;
if (!tok) // Ticket #6666 (crash upon invalid code)
break;
}
// Deallocation and then dereferencing pointer..
if (tok->varId() > 0) {
const std::map<unsigned int, VarInfo::AllocInfo>::const_iterator var = alloctype.find(tok->varId());
if (var != alloctype.end()) {
if (var->second.status == VarInfo::DEALLOC && (!Token::Match(tok, "%name% =") || tok->strAt(-1) == "*")) {
deallocUseError(tok, tok->str());
} else if (Token::simpleMatch(tok->tokAt(-2), "= &")) {
varInfo->erase(tok->varId());
} else if (tok->strAt(-1) == "=") {
varInfo->erase(tok->varId());
}
} else if (Token::Match(tok->previous(), "& %name% = %var% ;")) {
varInfo->referenced.insert(tok->tokAt(2)->varId());
}
}
if (tok->str() == "(" && tok->previous()->isName()) {
VarInfo::AllocInfo allocation(0, VarInfo::NOALLOC);
functionCall(tok->previous(), varInfo, allocation);
tok = tok->link();
continue;
}
// look for end of statement
if (!Token::Match(tok, "[;{}]") || Token::Match(tok->next(), "[;{}]"))
continue;
tok = tok->next();
if (!tok || tok == endToken)
break;
// parse statement, skip to last member
while (Token::Match(tok, "%name% ::|. %name% !!("))
tok = tok->tokAt(2);
// assignment..
if (Token::Match(tok, "%var% =")) {
// taking address of another variable..
if (Token::Match(tok->next(), "= %var% [+;]")) {
if (tok->tokAt(2)->varId() != tok->varId()) {
// If variable points at allocated memory => error
leakIfAllocated(tok, *varInfo);
// no multivariable checking currently => bail out for rhs variables
for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
break;
}
if (tok2->varId()) {
varInfo->erase(tok2->varId());
}
}
}
}
// is variable used in rhs?
bool used_in_rhs = false;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next()) {
if (tok2->str() == ";") {
break;
}
if (tok->varId() == tok2->varId()) {
used_in_rhs = true;
break;
}
}
// TODO: Better checking how the pointer is used in rhs?
if (used_in_rhs)
continue;
// Variable has already been allocated => error
if (conditionalAlloc.find(tok->varId()) == conditionalAlloc.end())
leakIfAllocated(tok, *varInfo);
varInfo->erase(tok->varId());
// not a local variable nor argument?
const Variable *var = tok->variable();
if (var && !var->isArgument() && (!var->isLocal() || var->isStatic())) {
continue;
}
// non-pod variable
if (_tokenizer->isCPP() && (!var || !var->typeStartToken()->isStandardType()))
continue;
// Don't check reference variables
if (var && var->isReference())
continue;
// allocation?
if (Token::Match(tok->tokAt(2), "%type% (")) {
int i = _settings->library.alloc(tok->tokAt(2));
if (i > 0) {
alloctype[tok->varId()].type = i;
alloctype[tok->varId()].status = VarInfo::ALLOC;
}
} else if (_tokenizer->isCPP() && tok->strAt(2) == "new") {
alloctype[tok->varId()].type = -1;
alloctype[tok->varId()].status = VarInfo::ALLOC;
}
// Assigning non-zero value variable. It might be used to
// track the execution for a later if condition.
if (Token::Match(tok->tokAt(2), "%num% ;") && MathLib::toLongNumber(tok->strAt(2)) != 0)
notzero.insert(tok->varId());
else if (Token::Match(tok->tokAt(2), "- %type% ;") && tok->tokAt(3)->isUpperCaseName())
notzero.insert(tok->varId());
else
notzero.erase(tok->varId());
}
// if/else
else if (Token::simpleMatch(tok, "if (")) {
// Parse function calls inside the condition
for (const Token *innerTok = tok->tokAt(2); innerTok; innerTok = innerTok->next()) {
if (innerTok->str() == ")")
break;
if (innerTok->str() == "(" && innerTok->previous()->isName()) {
VarInfo::AllocInfo allocation(_settings->library.dealloc(tok), VarInfo::DEALLOC);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
functionCall(innerTok->previous(), varInfo, allocation);
innerTok = innerTok->link();
}
}
const Token *tok2 = tok->linkAt(1);
if (Token::simpleMatch(tok2, ") {")) {
VarInfo varInfo1(*varInfo); // VarInfo for if code
VarInfo varInfo2(*varInfo); // VarInfo for else code
if (Token::Match(tok->next(), "( %var% )")) {
varInfo2.erase(tok->tokAt(2)->varId());
if (notzero.find(tok->tokAt(2)->varId()) != notzero.end())
varInfo2.clear();
} else if (Token::Match(tok->next(), "( ! %var% )|&&")) {
varInfo1.erase(tok->tokAt(3)->varId());
} else if (Token::Match(tok->next(), "( %name% ( ! %var% ) )|&&")) {
varInfo1.erase(tok->tokAt(5)->varId());
} else if (Token::Match(tok->next(), "( %var% < 0 )|&&")) {
varInfo1.erase(tok->tokAt(2)->varId());
} else if (Token::Match(tok->next(), "( 0 > %var% )|&&")) {
varInfo1.erase(tok->tokAt(4)->varId());
} else if (Token::Match(tok->next(), "( %var% > 0 )|&&")) {
varInfo2.erase(tok->tokAt(2)->varId());
} else if (Token::Match(tok->next(), "( 0 < %var% )|&&")) {
varInfo2.erase(tok->tokAt(4)->varId());
} else if (Token::Match(tok->next(), "( %var% == -1 )|&&")) {
varInfo1.erase(tok->tokAt(2)->varId());
} else if (Token::Match(tok->next(), "( -1 == %var% )|&&")) {
varInfo1.erase(tok->tokAt(4)->varId());
}
checkScope(tok2->next(), &varInfo1, notzero);
tok2 = tok2->linkAt(1);
if (Token::simpleMatch(tok2, "} else {")) {
checkScope(tok2->tokAt(2), &varInfo2, notzero);
tok = tok2->linkAt(2)->previous();
} else {
tok = tok2->previous();
}
VarInfo old;
old.swap(*varInfo);
// Conditional allocation in varInfo1
std::map<unsigned int, VarInfo::AllocInfo>::const_iterator it;
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (varInfo2.alloctype.find(it->first) == varInfo2.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation in varInfo2
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (varInfo1.alloctype.find(it->first) == varInfo1.alloctype.end() &&
old.alloctype.find(it->first) == old.alloctype.end()) {
varInfo->conditionalAlloc.insert(it->first);
}
}
// Conditional allocation/deallocation
for (it = varInfo1.alloctype.begin(); it != varInfo1.alloctype.end(); ++it) {
if (it->second.status == VarInfo::DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo2.erase(it->first);
}
}
for (it = varInfo2.alloctype.begin(); it != varInfo2.alloctype.end(); ++it) {
if (it->second.status == VarInfo::DEALLOC && conditionalAlloc.find(it->first) != conditionalAlloc.end()) {
varInfo->conditionalAlloc.erase(it->first);
varInfo1.erase(it->first);
}
}
alloctype.insert(varInfo1.alloctype.begin(), varInfo1.alloctype.end());
alloctype.insert(varInfo2.alloctype.begin(), varInfo2.alloctype.end());
possibleUsage.insert(varInfo1.possibleUsage.begin(), varInfo1.possibleUsage.end());
possibleUsage.insert(varInfo2.possibleUsage.begin(), varInfo2.possibleUsage.end());
}
}
// unknown control.. (TODO: handle loops)
else if ((Token::Match(tok, "%type% (") && Token::simpleMatch(tok->linkAt(1), ") {")) || Token::simpleMatch(tok, "do {")) {
varInfo->clear();
break;
}
// return
else if (tok->str() == "return") {
ret(tok, *varInfo);
varInfo->clear();
}
// throw
else if (_tokenizer->isCPP() && tok->str() == "throw") {
bool tryFound = false;
const Scope* scope = tok->scope();
while (scope && scope->isExecutable()) {
if (scope->type == Scope::eTry)
tryFound = true;
scope = scope->nestedIn;
}
// If the execution leaves the function then treat it as return
if (!tryFound)
ret(tok, *varInfo);
varInfo->clear();
}
// Function call..
else if (Token::Match(tok, "%type% (")) {
VarInfo::AllocInfo allocation(_settings->library.dealloc(tok), VarInfo::DEALLOC);
if (allocation.type == 0)
allocation.status = VarInfo::NOALLOC;
functionCall(tok, varInfo, allocation);
tok = tok->next()->link();
// Handle scopes that might be noreturn
if (allocation.status == VarInfo::NOALLOC && Token::simpleMatch(tok, ") ; }")) {
const std::string &functionName(tok->link()->previous()->str());
bool unknown = false;
if (_tokenizer->IsScopeNoReturn(tok->tokAt(2), &unknown)) {
if (!unknown)
varInfo->clear();
else if (_settings->library.leakignore.find(functionName) == _settings->library.leakignore.end() &&
_settings->library.use.find(functionName) == _settings->library.use.end())
varInfo->possibleUsageAll(functionName);
}
}
continue;
}
// delete
else if (_tokenizer->isCPP() && tok->str() == "delete") {
if (tok->strAt(1) == "[")
tok = tok->tokAt(3);
else
tok = tok->next();
while (Token::Match(tok, "%name% ::|."))
tok = tok->tokAt(2);
if (tok->varId() && tok->strAt(1) != "[") {
VarInfo::AllocInfo allocation(-1, VarInfo::DEALLOC);
changeAllocStatus(varInfo, allocation, tok, tok);
}
}
// goto => weird execution path
else if (tok->str() == "goto") {
varInfo->clear();
}
// continue/break
else if (Token::Match(tok, "continue|break ;")) {
varInfo->clear();
}
}
}
void CheckLeakAutoVar::changeAllocStatus(VarInfo *varInfo, const VarInfo::AllocInfo& allocation, const Token* tok, const Token* arg)
{
std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo->alloctype;
std::map<unsigned int, std::string> &possibleUsage = varInfo->possibleUsage;
const std::map<unsigned int, VarInfo::AllocInfo>::iterator var = alloctype.find(arg->varId());
if (var != alloctype.end()) {
if (allocation.status == VarInfo::NOALLOC) {
// possible usage
possibleUsage[arg->varId()] = tok->str();
if (var->second.status == VarInfo::DEALLOC && arg->previous()->str() == "&")
varInfo->erase(arg->varId());
} else if (var->second.status == VarInfo::DEALLOC) {
doubleFreeError(tok, arg->str(), allocation.type);
} else if (var->second.type != allocation.type) {
// mismatching allocation and deallocation
mismatchError(tok, arg->str());
varInfo->erase(arg->varId());
} else {
// deallocation
var->second.status = VarInfo::DEALLOC;
var->second.type = allocation.type;
}
} else if (allocation.status != VarInfo::NOALLOC) {
alloctype[arg->varId()].status = VarInfo::DEALLOC;
}
}
void CheckLeakAutoVar::functionCall(const Token *tok, VarInfo *varInfo, const VarInfo::AllocInfo& allocation)
{
// Ignore function call?
const bool ignore = bool(_settings->library.leakignore.find(tok->str()) != _settings->library.leakignore.end());
if (ignore)
return;
for (const Token *arg = tok->tokAt(2); arg; arg = arg->nextArgument()) {
if (_tokenizer->isCPP() && arg->str() == "new")
arg = arg->next();
if (Token::Match(arg, "%var% [-,)]") || Token::Match(arg, "& %var%")) {
// goto variable
if (arg->str() == "&")
arg = arg->next();
// Is variable allocated?
changeAllocStatus(varInfo, allocation, tok, arg);
} else if (Token::Match(arg, "%name% (")) {
functionCall(arg, varInfo, allocation);
}
}
}
void CheckLeakAutoVar::leakIfAllocated(const Token *vartok,
const VarInfo &varInfo)
{
const std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo.alloctype;
const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
const std::map<unsigned int, VarInfo::AllocInfo>::const_iterator var = alloctype.find(vartok->varId());
if (var != alloctype.end() && var->second.status != VarInfo::DEALLOC) {
const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(vartok->varId());
if (use == possibleUsage.end()) {
leakError(vartok, vartok->str(), var->second.type);
} else {
configurationInfo(vartok, use->second);
}
}
}
void CheckLeakAutoVar::ret(const Token *tok, const VarInfo &varInfo)
{
const std::map<unsigned int, VarInfo::AllocInfo> &alloctype = varInfo.alloctype;
const std::map<unsigned int, std::string> &possibleUsage = varInfo.possibleUsage;
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::map<unsigned int, VarInfo::AllocInfo>::const_iterator it = alloctype.begin(); it != alloctype.end(); ++it) {
// don't warn if variable is conditionally allocated
if (it->second.status != VarInfo::DEALLOC && varInfo.conditionalAlloc.find(it->first) != varInfo.conditionalAlloc.end())
continue;
// don't warn if there is a reference of the variable
if (varInfo.referenced.find(it->first) != varInfo.referenced.end())
continue;
const unsigned int varid = it->first;
const Variable *var = symbolDatabase->getVariableFromVarId(varid);
if (var) {
bool used = false;
for (const Token *tok2 = tok; tok2; tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (Token::Match(tok2, "return|(|, %varid% [);,]", varid)) {
used = true;
break;
}
if (Token::Match(tok2, "return|(|, & %varid% . %name% [);,]", varid)) {
used = true;
break;
}
}
// return deallocated pointer
if (used && it->second.status == VarInfo::DEALLOC)
deallocReturnError(tok, var->name());
else if (!used && it->second.status != VarInfo::DEALLOC) {
const std::map<unsigned int, std::string>::const_iterator use = possibleUsage.find(varid);
if (use == possibleUsage.end()) {
leakError(tok, var->name(), it->second.type);
} else {
configurationInfo(tok, use->second);
}
}
}
}
}
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