cppcheck/lib/checkexceptionsafety.h

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/*
* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2020 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/>.
*/
//---------------------------------------------------------------------------
#ifndef checkexceptionsafetyH
#define checkexceptionsafetyH
//---------------------------------------------------------------------------
#include "check.h"
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#include "config.h"
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#include "errortypes.h"
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#include "token.h"
#include "tokenize.h"
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#include <list>
#include <string>
class Settings;
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class ErrorLogger;
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// CWE ID used:
static const struct CWE CWE398(398U); // Indicator of Poor Code Quality
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static const struct CWE CWE703(703U); // Improper Check or Handling of Exceptional Conditions
/// @addtogroup Checks
/// @{
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/**
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* @brief %Check exception safety (exceptions shouldn't cause leaks nor corrupt data)
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*
* The problem with these checks is that Cppcheck can't determine what the valid
* values are for variables. But in some cases (dead pointers) it can be determined
* that certain variable values are corrupt.
*/
class CPPCHECKLIB CheckExceptionSafety : public Check {
public:
/** This constructor is used when registering the CheckClass */
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CheckExceptionSafety() : Check(myName()) {
}
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/** This constructor is used when running checks. */
CheckExceptionSafety(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
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: Check(myName(), tokenizer, settings, errorLogger) {
}
void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) OVERRIDE {
if (tokenizer->isC())
return;
CheckExceptionSafety checkExceptionSafety(tokenizer, settings, errorLogger);
checkExceptionSafety.destructors();
checkExceptionSafety.deallocThrow();
checkExceptionSafety.checkRethrowCopy();
checkExceptionSafety.checkCatchExceptionByValue();
checkExceptionSafety.nothrowThrows();
checkExceptionSafety.unhandledExceptionSpecification();
}
/** Don't throw exceptions in destructors */
void destructors();
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/** deallocating memory and then throw (dead pointer) */
void deallocThrow();
/** Don't rethrow a copy of the caught exception; use a bare throw instead */
void checkRethrowCopy();
/** @brief %Check for exceptions that are caught by value instead of by reference */
void checkCatchExceptionByValue();
/** @brief %Check for functions that throw that shouldn't */
void nothrowThrows();
/** @brief %Check for unhandled exception specification */
void unhandledExceptionSpecification();
private:
/** Don't throw exceptions in destructors */
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void destructorsError(const Token * const tok, const std::string &className) {
reportError(tok, Severity::warning, "exceptThrowInDestructor",
"Class " + className + " is not safe, destructor throws exception\n"
"The class " + className + " is not safe because its destructor "
"throws an exception. If " + className + " is used and an exception "
"is thrown that is caught in an outer scope the program will terminate.", CWE398, Certainty::normal);
}
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void deallocThrowError(const Token * const tok, const std::string &varname) {
reportError(tok, Severity::warning, "exceptDeallocThrow", "Exception thrown in invalid state, '" +
varname + "' points at deallocated memory.", CWE398, Certainty::normal);
}
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void rethrowCopyError(const Token * const tok, const std::string &varname) {
reportError(tok, Severity::style, "exceptRethrowCopy",
"Throwing a copy of the caught exception instead of rethrowing the original exception.\n"
"Rethrowing an exception with 'throw " + varname + ";' creates an unnecessary copy of '" + varname + "'. "
"To rethrow the caught exception without unnecessary copying or slicing, use a bare 'throw;'.", CWE398, Certainty::normal);
}
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void catchExceptionByValueError(const Token *tok) {
reportError(tok, Severity::style,
"catchExceptionByValue", "Exception should be caught by reference.\n"
"The exception is caught by value. It could be caught "
"as a (const) reference which is usually recommended in C++.", CWE398, Certainty::normal);
}
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void noexceptThrowError(const Token * const tok) {
reportError(tok, Severity::error, "throwInNoexceptFunction", "Exception thrown in function declared not to throw exceptions.", CWE398, Certainty::normal);
}
/** Missing exception specification */
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void unhandledExceptionSpecificationError(const Token * const tok1, const Token * const tok2, const std::string & funcname) {
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const std::string str1(tok1 ? tok1->str() : "foo");
const std::list<const Token*> locationList = { tok1, tok2 };
reportError(locationList, Severity::style, "unhandledExceptionSpecification",
"Unhandled exception specification when calling function " + str1 + "().\n"
"Unhandled exception specification when calling function " + str1 + "(). "
"Either use a try/catch around the function call, or add a exception specification for " + funcname + "() also.", CWE703, Certainty::inconclusive);
}
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/** Generate all possible errors (for --errorlist) */
void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const OVERRIDE {
CheckExceptionSafety c(nullptr, settings, errorLogger);
c.destructorsError(nullptr, "Class");
c.deallocThrowError(nullptr, "p");
c.rethrowCopyError(nullptr, "varname");
c.catchExceptionByValueError(nullptr);
c.noexceptThrowError(nullptr);
c.unhandledExceptionSpecificationError(nullptr, nullptr, "funcname");
}
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/** Short description of class (for --doc) */
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static std::string myName() {
return "Exception Safety";
}
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/** wiki formatted description of the class (for --doc) */
std::string classInfo() const OVERRIDE {
return "Checking exception safety\n"
"- Throwing exceptions in destructors\n"
"- Throwing exception during invalid state\n"
"- Throwing a copy of a caught exception instead of rethrowing the original exception\n"
"- Exception caught by value instead of by reference\n"
"- Throwing exception in noexcept, nothrow(), __attribute__((nothrow)) or __declspec(nothrow) function\n"
"- Unhandled exception specification when calling function foo()\n";
}
};
/// @}
//---------------------------------------------------------------------------
#endif // checkexceptionsafetyH