cppcheck/lib/checknullpointer.h

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/*
* Cppcheck - A tool for static C/C++ code analysis
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* Copyright (C) 2007-2014 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/>.
*/
//---------------------------------------------------------------------------
#ifndef checknullpointerH
#define checknullpointerH
//---------------------------------------------------------------------------
#include "config.h"
#include "check.h"
/// @addtogroup Checks
/// @{
/** @brief check for null pointer dereferencing */
class CPPCHECKLIB CheckNullPointer : public Check {
public:
/** @brief This constructor is used when registering the CheckNullPointer */
CheckNullPointer() : Check(myName()) {
}
/** @brief This constructor is used when running checks. */
CheckNullPointer(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger)
: Check(myName(), tokenizer, settings, errorLogger) {
}
/** @brief Run checks against the normal token list */
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void runChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {
CheckNullPointer checkNullPointer(tokenizer, settings, errorLogger);
checkNullPointer.nullPointer();
}
/** @brief Run checks against the simplified token list */
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void runSimplifiedChecks(const Tokenizer *tokenizer, const Settings *settings, ErrorLogger *errorLogger) {
CheckNullPointer checkNullPointer(tokenizer, settings, errorLogger);
checkNullPointer.nullConstantDereference();
}
/**
* @brief parse a function call and extract information about variable usage
* @param tok first token
* @param var variables that the function read / write.
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* @param library --library files data
* @param value 0 => invalid with null pointers as parameter.
* non-zero => invalid with uninitialized data.
*/
static void parseFunctionCall(const Token &tok,
std::list<const Token *> &var,
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const Library *library,
unsigned char value);
/**
* Is there a pointer dereference? Everything that should result in
* a nullpointer dereference error message will result in a true
* return value. If it's unknown if the pointer is dereferenced false
* is returned.
* @param tok token for the pointer
* @param unknown it is not known if there is a pointer dereference (could be reported as a debug message)
* @return true => there is a dereference
*/
static bool isPointerDeRef(const Token *tok, bool &unknown);
/** @brief possible null pointer dereference */
void nullPointer();
/**
* @brief Does one part of the check for nullPointer().
* Checking if pointer is NULL and then dereferencing it..
*/
void nullPointerByCheckAndDeRef();
/** @brief dereferencing null constant (after Tokenizer::simplifyKnownVariables) */
void nullConstantDereference();
void nullPointerError(const Token *tok); // variable name unknown / doesn't exist
void nullPointerError(const Token *tok, const std::string &varname, bool inconclusive=false);
void nullPointerError(const Token *tok, const std::string &varname, const Token* nullcheck, bool inconclusive = false);
void nullPointerDefaultArgError(const Token *tok, const std::string &varname);
private:
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/** Get error messages. Used by --errorlist */
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void getErrorMessages(ErrorLogger *errorLogger, const Settings *settings) const {
CheckNullPointer c(0, settings, errorLogger);
c.nullPointerError(0, "pointer");
}
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/** Name of check */
static std::string myName() {
return "Null pointer";
}
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/** class info in WIKI format. Used by --doc */
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std::string classInfo() const {
return "Null pointers\n"
"* null pointer dereferencing\n";
}
/**
* @brief Does one part of the check for nullPointer().
* looping through items in a linked list in a inner loop..
*/
void nullPointerLinkedList();
/**
* @brief Does one part of the check for nullPointer().
* Dereferencing a pointer and then checking if it's NULL..
*/
void nullPointerByDeRefAndChec();
/**
* @brief Does one part of the check for nullPointer().
* -# initialize pointer to 0
* -# conditionally assign pointer
* -# dereference pointer
*/
void nullPointerConditionalAssignment();
/**
* @brief Does one part of the check for nullPointer().
* -# default argument that sets a pointer to 0
* -# dereference pointer
*/
void nullPointerDefaultArgument();
/**
* @brief Removes any variable that may be assigned from pointerArgs.
*/
static void removeAssignedVarFromSet(const Token* tok, std::set<unsigned int>& pointerArgs);
/**
* @brief Investigate if function call can make pointer null. If
* the pointer is passed by value it can't be made a null pointer.
*/
static bool CanFunctionAssignPointer(const Token *functiontoken, unsigned int varid, bool& unknown);
};
/// @}
//---------------------------------------------------------------------------
#endif // checknullpointerH