300 lines
16 KiB
C++
300 lines
16 KiB
C++
/*
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* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2016 Cppcheck team.
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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//---------------------------------------------------------------------------
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// Check functions
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//---------------------------------------------------------------------------
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#include "checkfunctions.h"
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#include "symboldatabase.h"
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#include <cmath>
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//---------------------------------------------------------------------------
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// Register this check class (by creating a static instance of it)
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namespace {
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CheckFunctions instance;
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}
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static const CWE CWE252(252U); // Unchecked Return Value
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static const CWE CWE477(477U); // Use of Obsolete Functions
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static const CWE CWE758(758U); // Reliance on Undefined, Unspecified, or Implementation-Defined Behavior
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static const CWE CWE628(628U); // Function Call with Incorrectly Specified Arguments
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void CheckFunctions::checkProhibitedFunctions()
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{
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const bool checkAlloca = _settings->isEnabled("warning") && ((_settings->standards.c >= Standards::C99 && _tokenizer->isC()) || _settings->standards.cpp >= Standards::CPP11);
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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for (unsigned int i = 0; i < symbolDatabase->functionScopes.size(); i++) {
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const Scope* scope = symbolDatabase->functionScopes[i];
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for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
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if (tok->isName() && tok->varId() == 0 && tok->strAt(1) == "(") {
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// alloca() is special as it depends on the code being C or C++, so it is not in Library
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if (checkAlloca && Token::simpleMatch(tok, "alloca (") && (!tok->function() || tok->function()->nestedIn->type == Scope::eGlobal)) {
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if (_tokenizer->isC()) {
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if (_settings->standards.c > Standards::C89)
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reportError(tok, Severity::warning, "allocaCalled",
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"Obsolete function 'alloca' called. In C99 and later it is recommended to use a variable length array instead.\n"
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"The obsolete function 'alloca' is called. In C99 and later it is recommended to use a variable length array or "
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"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
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"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
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} else
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reportError(tok, Severity::warning, "allocaCalled",
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"Obsolete function 'alloca' called.\n"
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"The obsolete function 'alloca' is called. In C++11 and later it is recommended to use std::array<> or "
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"a dynamically allocated array instead. The function 'alloca' is dangerous for many reasons "
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"(http://stackoverflow.com/questions/1018853/why-is-alloca-not-considered-good-practice and http://linux.die.net/man/3/alloca).");
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} else {
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if (tok->function() && tok->function()->hasBody())
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continue;
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const Library::WarnInfo* wi = _settings->library.getWarnInfo(tok);
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if (wi) {
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if (_settings->isEnabled(Severity::toString(wi->severity)) && _settings->standards.c >= wi->standards.c && _settings->standards.cpp >= wi->standards.cpp) {
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reportError(tok, wi->severity, tok->str() + "Called", wi->message, CWE477, false);
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}
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}
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}
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}
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}
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}
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}
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//---------------------------------------------------------------------------
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// strtol(str, 0, radix) <- radix must be 0 or 2-36
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//---------------------------------------------------------------------------
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void CheckFunctions::invalidFunctionUsage()
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{
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const SymbolDatabase* symbolDatabase = _tokenizer->getSymbolDatabase();
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const std::size_t functions = symbolDatabase->functionScopes.size();
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for (std::size_t i = 0; i < functions; ++i) {
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const Scope * scope = symbolDatabase->functionScopes[i];
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for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
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if (!tok->isName() || !Token::Match(tok, "%name% ( !!)"))
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continue;
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const Token * const functionToken = tok;
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int argnr = 1;
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const Token *argtok = tok->tokAt(2);
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do {
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if (Token::Match(argtok, "%num% [,)]")) {
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if (MathLib::isInt(argtok->str()) &&
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!_settings->library.isargvalid(functionToken, argnr, MathLib::toLongNumber(argtok->str())))
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invalidFunctionArgError(argtok, functionToken->str(), argnr, _settings->library.validarg(functionToken, argnr));
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} else {
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const Token *top = argtok;
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while (top->astParent() && top->astParent()->str() != "," && top->astParent() != tok->next())
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top = top->astParent();
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const Token *var = top;
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while (Token::Match(var, ".|::"))
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var = var->astOperand2();
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if (Token::Match(top, "%comp%|%oror%|&&|!|true|false") ||
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(var && var->variable() && Token::simpleMatch(var->variable()->typeStartToken(), "bool"))) {
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if (_settings->library.isboolargbad(functionToken, argnr))
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invalidFunctionArgBoolError(top, functionToken->str(), argnr);
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// Are the values 0 and 1 valid?
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else if (!_settings->library.isargvalid(functionToken, argnr, 0))
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invalidFunctionArgError(top, functionToken->str(), argnr, _settings->library.validarg(functionToken, argnr));
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else if (!_settings->library.isargvalid(functionToken, argnr, 1))
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invalidFunctionArgError(top, functionToken->str(), argnr, _settings->library.validarg(functionToken, argnr));
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}
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}
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argnr++;
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argtok = argtok->nextArgument();
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} while (argtok && argtok->str() != ")");
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}
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}
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}
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void CheckFunctions::invalidFunctionArgError(const Token *tok, const std::string &functionName, int argnr, const std::string &validstr)
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{
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std::ostringstream errmsg;
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errmsg << "Invalid " << functionName << "() argument nr " << argnr;
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if (!tok)
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;
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else if (tok->isNumber())
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errmsg << ". The value is " << tok->str() << " but the valid values are '" << validstr << "'.";
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else if (tok->isComparisonOp())
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errmsg << ". The value is 0 or 1 (comparison result) but the valid values are '" << validstr << "'.";
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reportError(tok, Severity::error, "invalidFunctionArg", errmsg.str(), CWE628, false);
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}
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void CheckFunctions::invalidFunctionArgBoolError(const Token *tok, const std::string &functionName, int argnr)
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{
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std::ostringstream errmsg;
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errmsg << "Invalid " << functionName << "() argument nr " << argnr << ". A non-boolean value is required.";
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reportError(tok, Severity::error, "invalidFunctionArgBool", errmsg.str(), CWE628, false);
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}
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//---------------------------------------------------------------------------
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// Check for ignored return values.
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//---------------------------------------------------------------------------
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void CheckFunctions::checkIgnoredReturnValue()
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{
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if (!_settings->isEnabled("warning"))
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return;
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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const std::size_t functions = symbolDatabase->functionScopes.size();
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for (std::size_t i = 0; i < functions; ++i) {
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const Scope * scope = symbolDatabase->functionScopes[i];
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for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
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if (tok->varId() || !Token::Match(tok, "%name% (") || tok->strAt(-1) == ".")
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continue;
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if (!tok->scope()->isExecutable()) {
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tok = tok->scope()->classEnd;
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continue;
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}
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const Token* parent = tok;
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while (parent->astParent() && parent->astParent()->str() == "::")
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parent = parent->astParent();
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if (tok->next()->astOperand1() != parent)
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continue;
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if (!tok->next()->astParent() && (!tok->function() || !Token::Match(tok->function()->retDef, "void %name%")) && _settings->library.isUseRetVal(tok))
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ignoredReturnValueError(tok, tok->str());
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}
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}
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}
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void CheckFunctions::ignoredReturnValueError(const Token* tok, const std::string& function)
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{
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reportError(tok, Severity::warning, "ignoredReturnValue",
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"Return value of function " + function + "() is not used.", CWE252, false);
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}
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//---------------------------------------------------------------------------
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// Detect passing wrong values to <cmath> functions like atan(0, x);
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//---------------------------------------------------------------------------
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void CheckFunctions::checkMathFunctions()
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{
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const bool styleC99 = _settings->isEnabled("style") && _settings->standards.c != Standards::C89 && _settings->standards.cpp != Standards::CPP03;
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const bool printWarnings = _settings->isEnabled("warning");
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const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
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const std::size_t functions = symbolDatabase->functionScopes.size();
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for (std::size_t i = 0; i < functions; ++i) {
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const Scope * scope = symbolDatabase->functionScopes[i];
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for (const Token* tok = scope->classStart->next(); tok != scope->classEnd; tok = tok->next()) {
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if (tok->varId())
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continue;
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if (printWarnings && Token::Match(tok, "%name% ( !!)")) {
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if (tok->strAt(-1) != "."
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&& Token::Match(tok, "log|logf|logl|log10|log10f|log10l ( %num% )")) {
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const std::string& number = tok->strAt(2);
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bool isNegative = MathLib::isNegative(number);
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bool isInt = MathLib::isInt(number);
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bool isFloat = MathLib::isFloat(number);
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if (isNegative && isInt && MathLib::toLongNumber(number) <= 0) {
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mathfunctionCallWarning(tok); // case log(-2)
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} else if (isNegative && isFloat && MathLib::toDoubleNumber(number) <= 0.) {
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mathfunctionCallWarning(tok); // case log(-2.0)
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} else if (!isNegative && isFloat && MathLib::toDoubleNumber(number) <= 0.) {
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mathfunctionCallWarning(tok); // case log(0.0)
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} else if (!isNegative && isInt && MathLib::toLongNumber(number) <= 0) {
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mathfunctionCallWarning(tok); // case log(0)
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}
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}
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// acos( x ), asin( x ) where x is defined for interval [-1,+1], but not beyond
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else if (Token::Match(tok, "acos|acosl|acosf|asin|asinf|asinl ( %num% )")) {
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if (std::fabs(MathLib::toDoubleNumber(tok->strAt(2))) > 1.0)
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mathfunctionCallWarning(tok);
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}
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// sqrt( x ): if x is negative the result is undefined
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else if (Token::Match(tok, "sqrt|sqrtf|sqrtl ( %num% )")) {
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if (MathLib::isNegative(tok->strAt(2)))
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mathfunctionCallWarning(tok);
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}
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// atan2 ( x , y): x and y can not be zero, because this is mathematically not defined
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else if (Token::Match(tok, "atan2|atan2f|atan2l ( %num% , %num% )")) {
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if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNullValue(tok->strAt(4)))
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mathfunctionCallWarning(tok, 2);
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}
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// fmod ( x , y) If y is zero, then either a range error will occur or the function will return zero (implementation-defined).
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else if (Token::Match(tok, "fmod|fmodf|fmodl (")) {
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const Token* nextArg = tok->tokAt(2)->nextArgument();
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if (nextArg && nextArg->isNumber() && MathLib::isNullValue(nextArg->str()))
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mathfunctionCallWarning(tok, 2);
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}
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// pow ( x , y) If x is zero, and y is negative --> division by zero
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else if (Token::Match(tok, "pow|powf|powl ( %num% , %num% )")) {
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if (MathLib::isNullValue(tok->strAt(2)) && MathLib::isNegative(tok->strAt(4)))
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mathfunctionCallWarning(tok, 2);
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}
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}
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if (styleC99) {
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if (Token::Match(tok, "%num% - erf (") && Tokenizer::isOneNumber(tok->str()) && tok->next()->astOperand2() == tok->tokAt(3)) {
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mathfunctionCallWarning(tok, "1 - erf(x)", "erfc(x)");
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} else if (Token::simpleMatch(tok, "exp (") && Token::Match(tok->linkAt(1), ") - %num%") && Tokenizer::isOneNumber(tok->linkAt(1)->strAt(2)) && tok->linkAt(1)->next()->astOperand1() == tok->next()) {
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mathfunctionCallWarning(tok, "exp(x) - 1", "expm1(x)");
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} else if (Token::simpleMatch(tok, "log (") && tok->next()->astOperand2()) {
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const Token* plus = tok->next()->astOperand2();
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if (plus->str() == "+" && ((plus->astOperand1() && Tokenizer::isOneNumber(plus->astOperand1()->str())) || (plus->astOperand2() && Tokenizer::isOneNumber(plus->astOperand2()->str()))))
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mathfunctionCallWarning(tok, "log(1 + x)", "log1p(x)");
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}
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}
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}
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}
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}
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void CheckFunctions::mathfunctionCallWarning(const Token *tok, const unsigned int numParam)
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{
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if (tok) {
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if (numParam == 1)
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reportError(tok, Severity::warning, "wrongmathcall", "Passing value " + tok->strAt(2) + " to " + tok->str() + "() leads to implementation-defined result.", CWE758, false);
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else if (numParam == 2)
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reportError(tok, Severity::warning, "wrongmathcall", "Passing values " + tok->strAt(2) + " and " + tok->strAt(4) + " to " + tok->str() + "() leads to implementation-defined result.", CWE758, false);
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} else
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reportError(tok, Severity::warning, "wrongmathcall", "Passing value '#' to #() leads to implementation-defined result.", CWE758, false);
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}
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void CheckFunctions::mathfunctionCallWarning(const Token *tok, const std::string& oldexp, const std::string& newexp)
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{
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reportError(tok, Severity::style, "unpreciseMathCall", "Expression '" + oldexp + "' can be replaced by '" + newexp + "' to avoid loss of precision.", CWE758, false);
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}
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void CheckFunctions::checkLibraryMatchFunctions()
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{
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if (!_settings->checkLibrary || !_settings->isEnabled("information"))
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return;
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for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next()) {
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if (Token::Match(tok, "%name% (") &&
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!Token::Match(tok, "for|if|while|switch|sizeof|catch|asm|return") &&
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!tok->function() &&
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!tok->varId() &&
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!tok->type() &&
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!tok->isStandardType() &&
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tok->linkAt(1)->strAt(1) != "(" &&
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tok->astParent() == tok->next() &&
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_settings->library.isNotLibraryFunction(tok)) {
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reportError(tok,
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Severity::information,
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"checkLibraryFunction",
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"--check-library: There is no matching configuration for function " + tok->str() + "()");
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}
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}
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}
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