checkother.cpp

cppcheck is a static C/C++ code analyzer that checks for memory leaks, mismatching allocation-deallo

/*
 * Cppcheck - A tool for static C/C++ code analysis
 * Copyright (C) 2007-2009 Daniel Marjamäki, Reijo Tomperi, Nicolas Le Cam,
 * Leandro Penz, Kimmo Varis, Vesa Pikki
 *
 * 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/
 */


//---------------------------------------------------------------------------
#include "checkother.h"
#include <algorithm>
#include <list>
#include <map>
#include <sstream>
#include <cstdlib>     // <- atoi
#include <cstring>
#include <cctype>
//---------------------------------------------------------------------------




//---------------------------------------------------------------------------
// Warning on C-Style casts.. p = (kalle *)foo;
//---------------------------------------------------------------------------

CheckOther::CheckOther(const Tokenizer *tokenizer, const Settings &settings, ErrorLogger *errorLogger)
        : _settings(settings)
{
    _tokenizer = tokenizer;
    _errorLogger = errorLogger;
}

CheckOther::~CheckOther()
{

}

void CheckOther::WarningOldStylePointerCast()
{
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
    {
        // Old style pointer casting..
        if (!Token::Match(tok, "( %type% * ) %var%"))
            continue;

        // Is "type" a class?
        const std::string pattern("class " + tok->next()->str());
        if (!Token::findmatch(_tokenizer->tokens(), pattern.c_str()))
            continue;

        _errorLogger->cstyleCast(_tokenizer, tok);
    }
}




//---------------------------------------------------------------------------
// Redundant code..
//---------------------------------------------------------------------------

void CheckOther::WarningRedundantCode()
{

    // if (p) delete p
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
    {
        if (tok->str() != "if")
            continue;

        const char *varname1 = NULL;
        const Token *tok2 = NULL;

        if (Token::Match(tok, "if ( %var% )"))
        {
            varname1 = tok->strAt(2);
            tok2 = tok->tokAt(4);
        }
        else if (Token::Match(tok, "if ( %var% != NULL )"))
        {
            varname1 = tok->strAt(2);
            tok2 = tok->tokAt(6);
        }

        if (varname1 == NULL || tok2 == NULL)
            continue;

        bool err = false;
        if (tok2->str() == "{")
        {
            tok2 = tok2->next();

            if (Token::Match(tok2, "delete %var% ; }"))
            {
                err = (strcmp(tok2->strAt(1), varname1) == 0);
            }
            else if (Token::Match(tok2, "delete [ ] %var% ; }"))
            {
                err = (strcmp(tok2->strAt(1), varname1) == 0);
            }
            else if (Token::Match(tok2, "free ( %var% ) ; }"))
            {
                err = (strcmp(tok2->strAt(2), varname1) == 0);
            }
            else if (Token::Match(tok2, "kfree ( %var% ) ; }"))
            {
                err = (strcmp(tok2->strAt(2), varname1) == 0);
            }
        }
        else
        {
            if (Token::Match(tok2, "delete %var% ;"))
            {
                err = (strcmp(tok2->strAt(1), varname1) == 0);
            }
            else if (Token::Match(tok2, "delete [ ] %var% ;"))
            {
                err = (strcmp(tok2->strAt(1), varname1) == 0);
            }
            else if (Token::Match(tok2, "free ( %var% ) ;"))
            {
                err = (strcmp(tok2->strAt(2), varname1) == 0);
            }
            else if (Token::Match(tok2, "kfree ( %var% ) ;"))
            {
                err = (strcmp(tok2->strAt(2), varname1) == 0);
            }
        }

        if (err)
        {
            _errorLogger->redundantIfDelete0(_tokenizer, tok);
        }
    }



    // Redundant condition
    // if (haystack.find(needle) != haystack.end())
    //    haystack.remove(needle);
    redundantCondition2();
}
//---------------------------------------------------------------------------

void CheckOther::redundantCondition2()
{
    const char pattern[] = "if ( %var% . find ( %any% ) != %var% . end ( ) ) "
                           "{|{|"
                           "    %var% . remove ( %any% ) ; "
                           "}|}|";
    const Token *tok = Token::findmatch(_tokenizer->tokens(), pattern);
    while (tok)
    {
        bool b = Token::Match(tok->tokAt(15), "{");

        // Get tokens for the fields %var% and %any%
        const Token *var1 = tok->tokAt(2);
        const Token *any1 = tok->tokAt(6);
        const Token *var2 = tok->tokAt(9);
        const Token *var3 = tok->tokAt(b ? 16 : 15);
        const Token *any2 = tok->tokAt(b ? 20 : 19);

        // Check if all the "%var%" fields are the same and if all the "%any%" are the same..
        if (var1->str() == var2->str() &&
            var2->str() == var3->str() &&
            any1->str() == any2->str())
        {
            _errorLogger->redundantIfRemove(_tokenizer, tok);
        }

        tok = Token::findmatch(tok->next(), pattern);
    }
}
//---------------------------------------------------------------------------




//---------------------------------------------------------------------------
// if (condition) ....
//---------------------------------------------------------------------------

void CheckOther::WarningIf()
{
    if (ErrorLogger::ifNoAction(_settings))
    {
        // Search for 'if (condition);'
        for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
        {
            if (!Token::simpleMatch(tok, "if ("))
                continue;

            // Search for the end paranthesis for the condition..
            int parlevel = 0;
            for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
            {
                if (tok2->str() == "(")
                    ++parlevel;
                else if (tok2->str() == ")")
                {
                    --parlevel;
                    if (parlevel <= 0)
                    {
                        if (Token::Match(tok2, ") ; !!else"))
                        {
                            _errorLogger->ifNoAction(_tokenizer, tok);
                        }
                        break;
                    }
                }
            }
        }
    }

    if (ErrorLogger::conditionAlwaysTrueFalse(_settings))
    {
        // Search for 'a=b; if (a==b)'
        for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
        {
            // Begin statement?
            if (! Token::Match(tok, "[;{}]"))
                continue;
            tok = tok->next();
            if (! tok)
                break;

            if (!Token::Match(tok, "%var% = %var% ; if ( %var%"))
                continue;

            if (strcmp(tok->strAt(9), ")") != 0)
                continue;

            // var1 = var2 ; if ( var3 cond var4 )
            const char *var1 = tok->strAt(0);
            const char *var2 = tok->strAt(2);
            const char *var3 = tok->strAt(6);
            const char *cond = tok->strAt(7);
            const char *var4 = tok->strAt(8);

            // Check that var3 is equal with either var1 or var2
            if (strcmp(var1, var3) && strcmp(var2, var3))
                continue;

            // Check that var4 is equal with either var1 or var2
            if (strcmp(var1, var4) && strcmp(var2, var4))
                continue;

            // Check that there is a condition..
            const char *p[6] = {"==", "<=", ">=", "!=", "<", ">"};
            bool iscond = false;
            for (int i = 0; i < 6; i++)
            {
                if (strcmp(cond, p[i]) == 0)
                {
                    iscond = true;
                    break;
                }
            }
            if (!iscond)
                break;

            // we found the error. Report.
            bool b = false;
            for (int i = 0; i < 6; i++)
            {
                if (strcmp(cond, p[i]) == 0)
                    b = (i < 3);
            }
            _errorLogger->conditionAlwaysTrueFalse(_tokenizer, tok->tokAt(4), b ? "True" : "False");
        }
    }
}
//---------------------------------------------------------------------------




//---------------------------------------------------------------------------
// strtol(str, 0, radix)  <- radix must be 0 or 2-36
//---------------------------------------------------------------------------

void CheckOther::InvalidFunctionUsage()
{
    // strtol and strtoul..
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
    {
        if ((tok->str() != "strtol") && (tok->str() != "strtoul"))
            continue;

        // Locate the third parameter of the function call..
        int parlevel = 0;
        int param = 1;
        for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next())
        {
            if (Token::Match(tok2, "("))
                ++parlevel;
            else if (Token::Match(tok2, ")"))
                --parlevel;
            else if (parlevel == 1 && Token::Match(tok2, ","))
            {
                ++param;
                if (param == 3)
                {
                    if (Token::Match(tok2, ", %num% )"))
                    {
                        int radix = std::atoi(tok2->strAt(1));
                        if (!(radix == 0 || (radix >= 2 && radix <= 36)))
                        {
                            _errorLogger->dangerousUsageStrtol(_tokenizer, tok2);
                        }
                    }
                    break;
                }
            }
        }
    }

    // sprintf|snprintf overlapping data
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
    {
        // Get variable id of target buffer..
        unsigned int varid = 0;

        if (Token::Match(tok, "sprintf|snprintf ( %var% ,"))
            varid = tok->tokAt(2)->varId();

        else if (Token::Match(tok, "sprintf|snprintf ( %var% . %var% ,"))
            varid = tok->tokAt(4)->varId();

        if (varid == 0)
            continue;

        // goto ","
        const Token *tok2 = tok->tokAt(3);
        while (tok2 && tok2->str() != ",")
            tok2 = tok2->next();

        // is any source buffer overlapping the target buffer?
        int parlevel = 0;
        while ((tok2 = tok2->next()) != NULL)
        {
            if (tok2->str() == "(")
                ++parlevel;
            else if (tok2->str() == ")")
            {
                --parlevel;
                if (parlevel < 0)
                    break;
            }
            else if (parlevel == 0 && Token::Match(tok2, ", %varid% [,)]", varid))
            {
                _errorLogger->sprintfOverlappingData(_tokenizer, tok2->next(), tok2->next()->str());
                break;
            }
        }
    }
}
//---------------------------------------------------------------------------


//---------------------------------------------------------------------------
// Check for unsigned divisions
//---------------------------------------------------------------------------

void CheckOther::CheckUnsignedDivision()
{
    // Check for "ivar / uvar" and "uvar / ivar"
    std::map<std::string, char> varsign;
    for (const Token *tok = _tokenizer->tokens(); tok; tok = tok->next())
    {
        if (Token::Match(tok, "[{};(,] %type% %var% [;=,)]"))
        {
            const char *type = tok->strAt(1);
            if (strcmp(type, "char") == 0 || strcmp(type, "short") == 0 || strcmp(type, "int") == 0)
                varsign[tok->strAt(2)] = 's';
        }

        else if (Token::Match(tok, "[{};(,] unsigned %type% %var% [;=,)]"))
            varsign[tok->strAt(3)] = 'u';

        else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / %var%"))
        {
            if (ErrorLogger::udivWarning(_settings))
            {
                const char *varname1 = tok->strAt(1);
                const char *varname2 = tok->strAt(3);
                char sign1 = varsign[varname1];
                char sign2 = varsign[varname2];

                if (sign1 && sign2 && sign1 != sign2)
                {
                    // One of the operands are signed, the other is unsigned..
                    _errorLogger->udivWarning(_tokenizer, tok->next());
                }
            }
        }

        else if (!Token::Match(tok, "[).]") && Token::Match(tok->next(), "%var% / - %num%"))
        {
            if (ErrorLogger::udivError())
            {
                const char *varname1 = tok->strAt(1);
                char sign1 = varsign[varname1];
                if (sign1 == 'u')
                {
                    _errorLogger->udivError(_tokenizer, tok->next());
                }
            }
        }

        else if (Token::Match(tok, "[([=*/+-] - %num% / %var%"))
        {
            if (ErrorLogger::udivError())
            {
                const char *varname2 = tok->strAt(4);
                char sign2 = varsign[varname2];
                if (sign2 == 'u')
                {
                    _errorLogger->udivError(_tokenizer, tok->next());
                }
            }
        }
    }
}
//---------------------------------------------------------------------------



//---------------------------------------------------------------------------
// Check scope of variables..
//---------------------------------------------------------------------------


void CheckOther::CheckVariableScope()