1426 lines
56 KiB
C++
1426 lines
56 KiB
C++
/*
|
|
* Cppcheck - A tool for static C/C++ code analysis
|
|
* Copyright (C) 2007-2012 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/>.
|
|
*/
|
|
|
|
|
|
//---------------------------------------------------------------------------
|
|
#include "checknullpointer.h"
|
|
#include "executionpath.h"
|
|
#include "mathlib.h"
|
|
#include "symboldatabase.h"
|
|
#include <cctype>
|
|
//---------------------------------------------------------------------------
|
|
|
|
// Register this check class (by creating a static instance of it)
|
|
namespace {
|
|
CheckNullPointer instance;
|
|
}
|
|
|
|
//---------------------------------------------------------------------------
|
|
|
|
|
|
/** Is string uppercase? */
|
|
bool CheckNullPointer::isUpper(const std::string &str)
|
|
{
|
|
for (unsigned int i = 0; i < str.length(); ++i) {
|
|
if (std::islower(str[i]))
|
|
return false;
|
|
}
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* @brief parse a function call and extract information about variable usage
|
|
* @param tok first token
|
|
* @param var variables that the function read / write.
|
|
* @param value 0 => invalid with null pointers as parameter.
|
|
* 1-.. => invalid with uninitialized data.
|
|
*/
|
|
void CheckNullPointer::parseFunctionCall(const Token &tok, std::list<const Token *> &var, unsigned char value)
|
|
{
|
|
// standard functions that dereference first parameter..
|
|
static std::set<std::string> functionNames1_all;
|
|
static std::set<std::string> functionNames1_nullptr;
|
|
static std::set<std::string> functionNames1_uninit;
|
|
if (functionNames1_all.empty()) {
|
|
// cstdlib
|
|
functionNames1_all.insert("atoi");
|
|
functionNames1_all.insert("atof");
|
|
functionNames1_all.insert("atol");
|
|
functionNames1_all.insert("qsort");
|
|
functionNames1_all.insert("strtod");
|
|
functionNames1_all.insert("strtol");
|
|
functionNames1_all.insert("strtoul");
|
|
// cstring
|
|
functionNames1_all.insert("memchr");
|
|
functionNames1_all.insert("memcmp");
|
|
functionNames1_all.insert("strcat");
|
|
functionNames1_all.insert("strncat");
|
|
functionNames1_all.insert("strcoll");
|
|
functionNames1_all.insert("strchr");
|
|
functionNames1_all.insert("strrchr");
|
|
functionNames1_all.insert("strcmp");
|
|
functionNames1_all.insert("strncmp");
|
|
functionNames1_all.insert("strcspn");
|
|
functionNames1_all.insert("strdup");
|
|
functionNames1_all.insert("strndup");
|
|
functionNames1_all.insert("strpbrk");
|
|
functionNames1_all.insert("strlen");
|
|
functionNames1_all.insert("strspn");
|
|
functionNames1_all.insert("strstr");
|
|
// cstdio
|
|
functionNames1_all.insert("fclose");
|
|
functionNames1_all.insert("feof");
|
|
functionNames1_all.insert("fwrite");
|
|
functionNames1_all.insert("fseek");
|
|
functionNames1_all.insert("ftell");
|
|
functionNames1_all.insert("fputs");
|
|
functionNames1_all.insert("ferror");
|
|
functionNames1_all.insert("fgetc");
|
|
functionNames1_all.insert("fgetpos");
|
|
functionNames1_all.insert("fsetpos");
|
|
functionNames1_all.insert("freopen");
|
|
functionNames1_all.insert("fscanf");
|
|
functionNames1_all.insert("fprintf");
|
|
functionNames1_all.insert("fopen");
|
|
functionNames1_all.insert("rewind");
|
|
functionNames1_all.insert("printf");
|
|
functionNames1_all.insert("scanf");
|
|
functionNames1_all.insert("fscanf");
|
|
functionNames1_all.insert("sscanf");
|
|
functionNames1_all.insert("setbuf");
|
|
functionNames1_all.insert("setvbuf");
|
|
functionNames1_all.insert("rename");
|
|
functionNames1_all.insert("remove");
|
|
functionNames1_all.insert("puts");
|
|
functionNames1_all.insert("getc");
|
|
functionNames1_all.insert("clearerr");
|
|
// ctime
|
|
functionNames1_all.insert("asctime");
|
|
functionNames1_all.insert("ctime");
|
|
functionNames1_all.insert("mktime");
|
|
|
|
functionNames1_nullptr.insert("itoa");
|
|
functionNames1_nullptr.insert("mbstowcs");
|
|
functionNames1_nullptr.insert("wcstombs");
|
|
functionNames1_nullptr.insert("memcpy");
|
|
functionNames1_nullptr.insert("memmove");
|
|
functionNames1_nullptr.insert("memset");
|
|
functionNames1_nullptr.insert("strcpy");
|
|
functionNames1_nullptr.insert("sprintf");
|
|
functionNames1_nullptr.insert("vsprintf");
|
|
functionNames1_nullptr.insert("vprintf");
|
|
functionNames1_nullptr.insert("fprintf");
|
|
functionNames1_nullptr.insert("vfprintf");
|
|
functionNames1_nullptr.insert("tmpnam");
|
|
functionNames1_nullptr.insert("fread");
|
|
functionNames1_nullptr.insert("gets");
|
|
functionNames1_nullptr.insert("gmtime");
|
|
functionNames1_nullptr.insert("localtime");
|
|
functionNames1_nullptr.insert("strftime");
|
|
|
|
functionNames1_uninit.insert("perror");
|
|
functionNames1_uninit.insert("fflush");
|
|
}
|
|
|
|
// standard functions that dereference second parameter..
|
|
static std::set<std::string> functionNames2_all;
|
|
static std::set<std::string> functionNames2_nullptr;
|
|
if (functionNames2_all.empty()) {
|
|
functionNames2_all.insert("mbstowcs");
|
|
functionNames2_all.insert("wcstombs");
|
|
functionNames2_all.insert("memcmp");
|
|
functionNames2_all.insert("memcpy");
|
|
functionNames2_all.insert("memmove");
|
|
functionNames2_all.insert("strcat");
|
|
functionNames2_all.insert("strncat");
|
|
functionNames2_all.insert("strcmp");
|
|
functionNames2_all.insert("strncmp");
|
|
functionNames2_all.insert("strcoll");
|
|
functionNames2_all.insert("strcpy");
|
|
functionNames2_all.insert("strcspn");
|
|
functionNames2_all.insert("strncpy");
|
|
functionNames2_all.insert("strpbrk");
|
|
functionNames2_all.insert("strspn");
|
|
functionNames2_all.insert("strstr");
|
|
functionNames2_all.insert("strxfrm");
|
|
functionNames2_all.insert("sprintf");
|
|
functionNames2_all.insert("fprintf");
|
|
functionNames2_all.insert("fscanf");
|
|
functionNames2_all.insert("sscanf");
|
|
functionNames2_all.insert("fputs");
|
|
functionNames2_all.insert("fputc");
|
|
functionNames2_all.insert("ungetc");
|
|
functionNames2_all.insert("rename");
|
|
functionNames2_all.insert("putc");
|
|
functionNames2_all.insert("freopen");
|
|
|
|
functionNames2_nullptr.insert("frexp");
|
|
functionNames2_nullptr.insert("modf");
|
|
functionNames2_nullptr.insert("fgetpos");
|
|
}
|
|
|
|
if (Token::Match(&tok, "%var% ( )") || !tok.tokAt(2))
|
|
return;
|
|
|
|
const Token* firstParam = tok.tokAt(2);
|
|
const Token* secondParam = firstParam->nextArgument();
|
|
|
|
// 1st parameter..
|
|
if ((Token::Match(firstParam, "%var% ,|)") && firstParam->varId() > 0) ||
|
|
(value == 0 && Token::Match(firstParam, "0 ,|)"))) {
|
|
if (functionNames1_all.find(tok.str()) != functionNames1_all.end())
|
|
var.push_back(firstParam);
|
|
else if (value == 0 && functionNames1_nullptr.find(tok.str()) != functionNames1_nullptr.end())
|
|
var.push_back(firstParam);
|
|
else if (value != 0 && functionNames1_uninit.find(tok.str()) != functionNames1_uninit.end())
|
|
var.push_back(firstParam);
|
|
else if (value == 0 && Token::Match(&tok, "snprintf|vsnprintf|fnprintf|vfnprintf") && secondParam && secondParam->str() != "0") // Only if length (second parameter) is not zero
|
|
var.push_back(firstParam);
|
|
}
|
|
|
|
// 2nd parameter..
|
|
if (secondParam && ((value == 0 && secondParam->str() == "0") || (Token::Match(secondParam, "%var%") && secondParam->varId() > 0))) {
|
|
if (functionNames2_all.find(tok.str()) != functionNames2_all.end())
|
|
var.push_back(secondParam);
|
|
else if (value == 0 && functionNames2_nullptr.find(tok.str()) != functionNames2_nullptr.end())
|
|
var.push_back(secondParam);
|
|
}
|
|
|
|
if (Token::Match(&tok, "printf|sprintf|snprintf|fprintf|fnprintf|scanf|sscanf|fscanf")) {
|
|
const Token* argListTok = 0; // Points to first va_list argument
|
|
std::string formatString;
|
|
bool scan = Token::Match(&tok, "scanf|sscanf|fscanf");
|
|
|
|
if (Token::Match(&tok, "printf|scanf ( %str%")) {
|
|
formatString = firstParam->strValue();
|
|
argListTok = secondParam;
|
|
} else if (Token::Match(&tok, "sprintf|fprintf|sscanf|fscanf")) {
|
|
const Token* formatStringTok = secondParam; // Find second parameter (format string)
|
|
if (formatStringTok && formatStringTok->type() == Token::eString) {
|
|
argListTok = formatStringTok->nextArgument(); // Find third parameter (first argument of va_args)
|
|
formatString = formatStringTok->strValue();
|
|
}
|
|
} else if (Token::Match(&tok, "snprintf|fnprintf") && secondParam) {
|
|
const Token* formatStringTok = secondParam->nextArgument(); // Find third parameter (format string)
|
|
if (formatStringTok && formatStringTok->type() == Token::eString) {
|
|
argListTok = formatStringTok->nextArgument(); // Find fourth parameter (first argument of va_args)
|
|
formatString = formatStringTok->strValue();
|
|
}
|
|
}
|
|
|
|
if (argListTok) {
|
|
bool percent = false;
|
|
for (std::string::iterator i = formatString.begin(); i != formatString.end(); ++i) {
|
|
if (*i == '%') {
|
|
percent = !percent;
|
|
} else if (percent) {
|
|
percent = false;
|
|
|
|
bool _continue = false;
|
|
while (!std::isalpha(*i)) {
|
|
if (*i == '*') {
|
|
if (scan)
|
|
_continue = true;
|
|
else
|
|
argListTok = argListTok->nextArgument();
|
|
}
|
|
++i;
|
|
if (!argListTok || i == formatString.end())
|
|
return;
|
|
}
|
|
if (_continue)
|
|
continue;
|
|
|
|
if ((*i == 'n' || *i == 's' || scan) && (!scan || value == 0)) {
|
|
if ((value == 0 && argListTok->str() == "0") || (argListTok->varId() > 0)) {
|
|
var.push_back(argListTok);
|
|
}
|
|
}
|
|
|
|
if (*i != 'm') // %m is a non-standard glibc extension that requires no parameter
|
|
argListTok = argListTok->nextArgument(); // Find next argument
|
|
if (!argListTok)
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/**
|
|
* 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
|
|
*/
|
|
bool CheckNullPointer::isPointerDeRef(const Token *tok, bool &unknown, const SymbolDatabase* symbolDatabase)
|
|
{
|
|
const bool inconclusive = unknown;
|
|
|
|
unknown = false;
|
|
|
|
// Dereferencing pointer..
|
|
if (tok->strAt(-1) == "*" && (Token::Match(tok->tokAt(-2), "return|throw|;|{|}|:|[|(|,") || tok->tokAt(-2)->isOp() || tok->tokAt(-2)->isAssignmentOp()) && !Token::Match(tok->tokAt(-3), "sizeof|decltype"))
|
|
return true;
|
|
|
|
// read/write member variable
|
|
if (!Token::simpleMatch(tok->tokAt(-2), "& (") && !Token::Match(tok->tokAt(-2), "sizeof|decltype (") && tok->strAt(-1) != "&" && tok->strAt(-1) != "&&" && Token::Match(tok->next(), ". %var%")) {
|
|
if (tok->strAt(3) != "(")
|
|
return true;
|
|
unknown = true;
|
|
return false;
|
|
}
|
|
|
|
if (Token::Match(tok, "%var% [") && (tok->previous()->str() != "&" || Token::Match(tok->next()->link()->next(), "[.(]")))
|
|
return true;
|
|
|
|
if (Token::Match(tok, "%var% ("))
|
|
return true;
|
|
|
|
if (Token::Match(tok, "%var% = %var% .") &&
|
|
tok->varId() > 0 &&
|
|
tok->varId() == tok->tokAt(2)->varId())
|
|
return true;
|
|
|
|
// std::string dereferences nullpointers
|
|
if (Token::Match(tok->tokAt(-4), "std :: string ( %var% )"))
|
|
return true;
|
|
if (Token::Match(tok->tokAt(-2), "%var% ( %var% )")) {
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(tok->tokAt(-2)->varId());
|
|
if (var && !var->isPointer() && !var->isArray() && Token::Match(var->typeStartToken(), "std :: string !!::"))
|
|
return true;
|
|
}
|
|
|
|
// streams dereference nullpointers
|
|
if (Token::Match(tok->previous(), "<<|>> %var%")) {
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(tok->varId());
|
|
if (var && var->isPointer() && var->typeStartToken()->str() == "char") { // Only outputing or reading to char* can cause problems
|
|
const Token* tok2 = tok->previous(); // Find start of statement
|
|
for (; tok2; tok2 = tok2->previous()) {
|
|
if (Token::Match(tok2->previous(), ";|{|}|:"))
|
|
break;
|
|
}
|
|
if (Token::Match(tok2, "std :: cout|cin|cerr"))
|
|
return true;
|
|
if (tok2 && tok2->varId() != 0) {
|
|
const Variable* var2 = symbolDatabase->getVariableFromVarId(tok2->varId());
|
|
if (var2 && Token::Match(var2->typeStartToken(), "std :: istream|ifstream|istringstream|ostream|ofstream|ostringstream|stringstream|fstream|iostream"))
|
|
return true;
|
|
}
|
|
}
|
|
}
|
|
|
|
unsigned int ovarid = 0;
|
|
if (Token::Match(tok, "%var% ==|!= %var%"))
|
|
ovarid = tok->tokAt(2)->varId();
|
|
else if (Token::Match(tok->tokAt(-2), "%var% ==|!= %var%"))
|
|
ovarid = tok->tokAt(-2)->varId();
|
|
else if (Token::Match(tok->tokAt(-2), "%var% =|+=|+ %var% )|]|,|;|+"))
|
|
ovarid = tok->tokAt(-2)->varId();
|
|
if (ovarid) {
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(ovarid);
|
|
if (var && !var->isPointer() && !var->isArray() && Token::Match(var->typeStartToken(), "std :: string !!::"))
|
|
return true;
|
|
}
|
|
|
|
// Check if it's NOT a pointer dereference.
|
|
// This is most useful in inconclusive checking
|
|
if (inconclusive) {
|
|
// Not a dereference..
|
|
if (Token::Match(tok, "%var% ="))
|
|
return false;
|
|
|
|
// OK to delete a null
|
|
if (Token::Match(tok->previous(), "delete %var%") || Token::Match(tok->tokAt(-3), "delete [ ] %var%"))
|
|
return false;
|
|
|
|
// OK to check if pointer is null
|
|
// OK to take address of pointer
|
|
if (Token::Match(tok->previous(), "!|& %var%"))
|
|
return false;
|
|
|
|
// OK to pass pointer to function
|
|
if (Token::Match(tok->previous(), "[(,] %var% [,)]"))
|
|
return false;
|
|
|
|
// Compare pointer
|
|
if (Token::Match(tok->previous(), "(|&&|%oror%|==|!= %var%"))
|
|
return false;
|
|
if (Token::Match(tok, "%var% &&|%oror%|==|!=|)"))
|
|
return false;
|
|
|
|
// Taking address
|
|
if (Token::Match(tok->previous(), "return|= %var% ;"))
|
|
return false;
|
|
|
|
// (void)var
|
|
if (Token::Match(tok->previous(), "[{;}] %var% ;"))
|
|
return false;
|
|
|
|
// unknown if it's a dereference
|
|
unknown = true;
|
|
}
|
|
|
|
// assume that it's not a dereference (no false positives)
|
|
return false;
|
|
}
|
|
|
|
|
|
// check if function can assign pointer
|
|
bool CheckNullPointer::CanFunctionAssignPointer(const Token *functiontoken, unsigned int varid) const
|
|
{
|
|
if (Token::Match(functiontoken, "if|while|for|switch|sizeof|catch"))
|
|
return false;
|
|
|
|
int argumentNumber = 0;
|
|
for (const Token *arg = functiontoken->tokAt(2); arg; arg = arg->nextArgument()) {
|
|
++argumentNumber;
|
|
if (Token::Match(arg, "%varid% [,)]", varid)) {
|
|
const Token *ftok = _tokenizer->getFunctionTokenByName(functiontoken->str().c_str());
|
|
if (!Token::Match(ftok, "%type% (")) {
|
|
// assume that the function might assign the pointer
|
|
return true;
|
|
}
|
|
|
|
ftok = ftok->tokAt(2);
|
|
while (ftok && argumentNumber > 1) {
|
|
ftok = ftok->nextArgument();
|
|
--argumentNumber;
|
|
}
|
|
|
|
// check if it's a pointer parameter..
|
|
while (ftok && ftok->isName())
|
|
ftok = ftok->next();
|
|
if (Token::Match(ftok, "* *| const| %var% [,)]"))
|
|
// parameter is passed by value
|
|
return false;
|
|
}
|
|
}
|
|
|
|
// pointer is not passed
|
|
return false;
|
|
}
|
|
|
|
|
|
|
|
void CheckNullPointer::nullPointerAfterLoop()
|
|
{
|
|
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
// Locate insufficient null-pointer handling after loop
|
|
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
|
|
// only interested in while ( %var% )
|
|
// TODO: Aren't there false negatives. Shouldn't other loops be handled such as:
|
|
// - while ( ! %var% )
|
|
const Token* const tok = i->classDef;
|
|
if (i->type != Scope::eWhile || !Token::Match(tok, "while ( %var% )|&&"))
|
|
continue;
|
|
|
|
// Get variable id for the loop variable
|
|
const Variable* var(symbolDatabase->getVariableFromVarId(tok->tokAt(2)->varId()));
|
|
|
|
// Is variable a pointer?
|
|
if (!var || !var->isPointer())
|
|
continue;
|
|
|
|
// Get variable name for the loop variable
|
|
const std::string& varname(tok->strAt(2));
|
|
|
|
// Locate the end of the while loop body..
|
|
const Token *tok2 = tok->next()->link()->next()->link();
|
|
|
|
// Is this checking inconclusive?
|
|
bool inconclusive = false;
|
|
|
|
if (!tok2)
|
|
continue;
|
|
// Check if the variable is dereferenced after the while loop
|
|
while (NULL != (tok2 = tok2->next())) {
|
|
// inner and outer scopes
|
|
if (tok2->str() == "{" || tok2->str() == "}") {
|
|
// Not inconclusive: bail out
|
|
if (!_settings->inconclusive)
|
|
break;
|
|
|
|
inconclusive = true;
|
|
|
|
if (tok2->str() == "}") {
|
|
// "}" => leaving function? then break.
|
|
const Token *tok3 = tok2->link()->previous();
|
|
if (!tok3 || !Token::Match(tok3, "[);]"))
|
|
break;
|
|
if (tok3->str() == ")" && !Token::Match(tok3->link()->previous(), "if|for|while"))
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Stop checking if "break" is found
|
|
else if (tok2->str() == "break")
|
|
break;
|
|
|
|
// loop variable is found..
|
|
else if (tok2->varId() == var->varId()) {
|
|
// dummy variable.. is it unknown if pointer is dereferenced or not?
|
|
bool unknown = _settings->inconclusive;
|
|
|
|
// Is the loop variable dereferenced?
|
|
if (CheckNullPointer::isPointerDeRef(tok2, unknown, symbolDatabase)) {
|
|
nullPointerError(tok2, varname, tok->linenr(), inconclusive);
|
|
}
|
|
|
|
else if (unknown && _settings->inconclusive) {
|
|
nullPointerError(tok2, varname, tok->linenr(), true);
|
|
}
|
|
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerLinkedList()
|
|
{
|
|
const SymbolDatabase* const symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
// looping through items in a linked list in a inner loop.
|
|
// Here is an example:
|
|
// for (const Token *tok = tokens; tok; tok = tok->next) {
|
|
// if (tok->str() == "hello")
|
|
// tok = tok->next; // <- tok might become a null pointer!
|
|
// }
|
|
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
|
|
const Token* const tok1 = i->classDef;
|
|
// search for a "for" scope..
|
|
if (i->type != Scope::eFor || !tok1)
|
|
continue;
|
|
|
|
// is there any dereferencing occurring in the for statement
|
|
const Token* end2 = tok1->linkAt(1);
|
|
for (const Token *tok2 = tok1->tokAt(2); tok2 != end2; tok2 = tok2->next()) {
|
|
// Dereferencing a variable inside the "for" parentheses..
|
|
if (Token::Match(tok2, "%var% . %var%")) {
|
|
// Variable id for dereferenced variable
|
|
const unsigned int varid(tok2->varId());
|
|
if (varid == 0)
|
|
continue;
|
|
|
|
// Is this variable a pointer?
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(varid);
|
|
if (!var || !var->isPointer())
|
|
continue;
|
|
|
|
if (Token::Match(tok2->tokAt(-2), "%varid% ?", varid))
|
|
continue;
|
|
|
|
// Check usage of dereferenced variable in the loop..
|
|
for (std::list<Scope*>::const_iterator j = i->nestedList.begin(); j != i->nestedList.end(); ++j) {
|
|
Scope* scope = *j;
|
|
if (scope->type != Scope::eWhile)
|
|
continue;
|
|
|
|
// TODO: are there false negatives for "while ( %varid% ||"
|
|
if (Token::Match(scope->classDef->next(), "( %varid% &&|)", varid)) {
|
|
// Make sure there is a "break" or "return" inside the loop.
|
|
// Without the "break" a null pointer could be dereferenced in the
|
|
// for statement.
|
|
// indentlevel4 is a counter for { and }. When scanning the code with tok4
|
|
unsigned int indentlevel4 = 1;
|
|
for (const Token *tok4 = scope->classStart; tok4; tok4 = tok4->next()) {
|
|
if (tok4->str() == "{")
|
|
++indentlevel4;
|
|
else if (tok4->str() == "}") {
|
|
if (indentlevel4 <= 1) {
|
|
nullPointerError(tok1, var->name(), scope->classDef->linenr());
|
|
break;
|
|
}
|
|
--indentlevel4;
|
|
}
|
|
|
|
// There is a "break" or "return" inside the loop.
|
|
// TODO: there can be false negatives. There could still be
|
|
// execution paths that are not properly terminated
|
|
else if (tok4->str() == "break" || tok4->str() == "return")
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerStructByDeRefAndChec()
|
|
{
|
|
// Dereferencing a struct pointer and then checking if it's NULL..
|
|
|
|
// skipvar: don't check vars that has been tested against null already
|
|
std::set<unsigned int> skipvar;
|
|
skipvar.insert(0);
|
|
|
|
// Scan through all tokens
|
|
for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next()) {
|
|
// Checking if some pointer is null.
|
|
// then add the pointer to skipvar => is it known that it isn't NULL
|
|
if (Token::Match(tok1, "if|while ( !| %var% )")) {
|
|
tok1 = tok1->tokAt(2);
|
|
if (tok1->str() == "!")
|
|
tok1 = tok1->next();
|
|
skipvar.insert(tok1->varId());
|
|
continue;
|
|
} else if (Token::Match(tok1, "( ! %var% %oror%") ||
|
|
Token::Match(tok1, "( %var% &&")) {
|
|
// TODO: there are false negatives caused by this. The
|
|
// variable should be removed from skipvar after the
|
|
// condition
|
|
tok1 = tok1->next();
|
|
if (tok1->str() == "!")
|
|
tok1 = tok1->next();
|
|
skipvar.insert(tok1->varId());
|
|
continue;
|
|
}
|
|
|
|
bool inconclusive = false;
|
|
|
|
/**
|
|
* @todo There are lots of false negatives here. A dereference
|
|
* is only investigated if a few specific conditions are met.
|
|
*/
|
|
|
|
// dereference in assignment
|
|
if (Token::Match(tok1, "[;{}] %var% . %var%")) {
|
|
tok1 = tok1->next();
|
|
if (tok1->strAt(3) == "(") {
|
|
if (!_settings->inconclusive)
|
|
continue;
|
|
inconclusive = true;
|
|
}
|
|
}
|
|
|
|
// dereference in assignment
|
|
else if (Token::Match(tok1, "[{};] %var% = %var% . %var%")) {
|
|
if (tok1->strAt(1) == tok1->strAt(3))
|
|
continue;
|
|
tok1 = tok1->tokAt(3);
|
|
}
|
|
|
|
// dereference in condition
|
|
else if (Token::Match(tok1, "if ( !| %var% .")) {
|
|
tok1 = tok1->tokAt(2);
|
|
if (tok1->str() == "!")
|
|
tok1 = tok1->next();
|
|
}
|
|
|
|
// dereference in function call (but not sizeof|decltype)
|
|
else if ((Token::Match(tok1->tokAt(-2), "%var% ( %var% . %var%") && !Token::Match(tok1->tokAt(-2), "sizeof|decltype ( %var% . %var%")) ||
|
|
Token::Match(tok1->previous(), ", %var% . %var%")) {
|
|
// Is the function return value taken by the pointer?
|
|
bool assignment = false;
|
|
const unsigned int varid1(tok1->varId());
|
|
if (varid1 == 0)
|
|
continue;
|
|
const Token *tok2 = tok1->previous();
|
|
while (tok2 && !Token::Match(tok2, "[;{}]")) {
|
|
if (Token::Match(tok2, "%varid% =", varid1)) {
|
|
assignment = true;
|
|
break;
|
|
}
|
|
tok2 = tok2->previous();
|
|
}
|
|
if (assignment)
|
|
continue;
|
|
|
|
// Is the dereference checked with a previous &&
|
|
bool checked = false;
|
|
for (tok2 = tok1->tokAt(-2); tok2; tok2 = tok2->previous()) {
|
|
if (Token::Match(tok2, "[,(;{}]"))
|
|
break;
|
|
else if (tok2->str() == ")")
|
|
tok2 = tok2->link();
|
|
else if (Token::Match(tok2, "%varid% &&", varid1)) {
|
|
checked = true;
|
|
break;
|
|
}
|
|
}
|
|
if (checked)
|
|
continue;
|
|
}
|
|
|
|
// Goto next token
|
|
else {
|
|
continue;
|
|
}
|
|
|
|
// struct dereference was found - investigate if it is later
|
|
// checked that it is not NULL
|
|
const unsigned int varid1(tok1->varId());
|
|
if (skipvar.find(varid1) != skipvar.end())
|
|
continue;
|
|
|
|
// name of struct pointer
|
|
const std::string& varname(tok1->str());
|
|
|
|
// is pointer local?
|
|
bool isLocal = false;
|
|
const Variable * var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(tok1->varId());
|
|
if (!var)
|
|
continue;
|
|
if (var->isLocal() || var->isArgument())
|
|
isLocal = true;
|
|
|
|
// member function may or may not nullify the pointer if it's global (#2647)
|
|
if (!isLocal) {
|
|
const Token *tok2 = tok1;
|
|
while (Token::Match(tok2, "%var% ."))
|
|
tok2 = tok2->tokAt(2);
|
|
if (Token::Match(tok2,"%var% ("))
|
|
continue;
|
|
}
|
|
|
|
// count { and } using tok2
|
|
unsigned int indentlevel2 = 0;
|
|
for (const Token *tok2 = tok1->tokAt(3); tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "{")
|
|
++indentlevel2;
|
|
|
|
else if (tok2->str() == "}") {
|
|
if (indentlevel2 == 0)
|
|
break;
|
|
--indentlevel2;
|
|
}
|
|
|
|
// label / ?:
|
|
else if (tok2->str() == ":")
|
|
break;
|
|
|
|
// function call..
|
|
else if (Token::Match(tok2, "[;{}] %var% (") && CanFunctionAssignPointer(tok2->next(), varid1)) {
|
|
if (!_settings->inconclusive)
|
|
break;
|
|
inconclusive = true;
|
|
}
|
|
|
|
// Reassignment of the struct
|
|
else if (tok2->varId() == varid1) {
|
|
if (tok2->next()->str() == "=") {
|
|
// Avoid false positives when there is 'else if'
|
|
// TODO: can this be handled better?
|
|
if (tok1->strAt(-2) == "if")
|
|
skipvar.insert(varid1);
|
|
break;
|
|
}
|
|
if (Token::Match(tok2->tokAt(-2), "[,(] &"))
|
|
break;
|
|
}
|
|
|
|
// Loop..
|
|
/** @todo don't bail out if the variable is not used in the loop */
|
|
else if (tok2->str() == "do")
|
|
break;
|
|
|
|
// return/break at base level => stop checking
|
|
else if (indentlevel2 == 0 && (tok2->str() == "return" || tok2->str() == "break"))
|
|
break;
|
|
|
|
// Function call: If the pointer is not a local variable it
|
|
// might be changed by the call.
|
|
else if (Token::Match(tok2, "[;{}] %var% (") &&
|
|
Token::simpleMatch(tok2->linkAt(2), ") ;") && !isLocal) {
|
|
break;
|
|
}
|
|
|
|
// Check if pointer is null.
|
|
// TODO: false negatives for "if (!p || .."
|
|
else if (!tok2->isExpandedMacro() && Token::Match(tok2, "if ( !| %varid% )|&&", varid1)) {
|
|
// Is this variable a pointer?
|
|
if (var->isPointer())
|
|
nullPointerError(tok1, varname, tok2->linenr(), inconclusive);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerByDeRefAndChec()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
// Dereferencing a pointer and then checking if it's NULL..
|
|
// This check will first scan for the check. And then scan backwards
|
|
// from the check, searching for dereferencing.
|
|
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
|
|
// TODO: false negatives.
|
|
// - logical operators
|
|
// - while
|
|
const Token* const tok = i->classDef;
|
|
if (i->type == Scope::eIf && tok && !tok->isExpandedMacro() && Token::Match(tok, "if ( !| %var% )|%oror%|&&")) {
|
|
const Token * vartok = tok->tokAt(2);
|
|
if (vartok->str() == "!")
|
|
vartok = vartok->next();
|
|
|
|
// Variable id for pointer
|
|
const unsigned int varid(vartok->varId());
|
|
if (varid == 0)
|
|
continue;
|
|
|
|
// Name of pointer
|
|
const std::string& varname(vartok->str());
|
|
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(varid);
|
|
// Check that variable is a pointer..
|
|
if (!var || !var->isPointer())
|
|
continue;
|
|
|
|
const Token * const decltok = var->nameToken();
|
|
bool inconclusive = false;
|
|
|
|
for (const Token *tok1 = tok->previous(); tok1 && tok1 != decltok; tok1 = tok1->previous()) {
|
|
if (tok1->str() == ")" && Token::Match(tok1->link()->previous(), "%var% (")) {
|
|
const Token *tok2 = tok1->link();
|
|
while (tok2 && !Token::Match(tok2, "[;{}?:]"))
|
|
tok2 = tok2->previous();
|
|
if (Token::Match(tok2, "[?:]"))
|
|
break;
|
|
if (Token::Match(tok2, "[;{}] %varid% = %var%", varid))
|
|
break;
|
|
|
|
if (Token::Match(tok1->link()->previous(), "while ( %varid%", varid))
|
|
break;
|
|
|
|
if (Token::Match(tok1->link(), "( ! %varid% %oror%", varid) ||
|
|
Token::Match(tok1->link(), "( %varid% &&", varid)) {
|
|
tok1 = tok1->link();
|
|
continue;
|
|
}
|
|
|
|
if (Token::simpleMatch(tok1->link()->previous(), "sizeof (")) {
|
|
tok1 = tok1->link()->previous();
|
|
continue;
|
|
}
|
|
|
|
if (Token::Match(tok2, "[;{}] %var% ( %varid% ,", varid)) {
|
|
std::list<const Token *> varlist;
|
|
parseFunctionCall(*(tok2->next()), varlist, 0);
|
|
if (!varlist.empty() && varlist.front() == tok2->tokAt(3)) {
|
|
nullPointerError(tok2->tokAt(3), varname, tok->linenr(), inconclusive);
|
|
break;
|
|
}
|
|
}
|
|
|
|
// Passing pointer as parameter..
|
|
if (Token::Match(tok2, "[;{}] %type% (")) {
|
|
if (CanFunctionAssignPointer(tok2->next(), varid)) {
|
|
if (!_settings->inconclusive)
|
|
break;
|
|
inconclusive = true;
|
|
}
|
|
}
|
|
|
|
// calling unknown function => it might initialize the pointer
|
|
if (!(var->isLocal() || var->isArgument()))
|
|
break;
|
|
}
|
|
|
|
if (tok1->str() == "break")
|
|
break;
|
|
|
|
if (tok1->varId() == varid) {
|
|
// Don't write warning if the dereferencing is
|
|
// guarded by ?: or &&
|
|
const Token *tok2 = tok1->previous();
|
|
if (tok2 && (tok2->isArithmeticalOp() || tok2->str() == "(")) {
|
|
while (tok2 && !Token::Match(tok2, "[;{}?:]")) {
|
|
if (tok2->str() == ")")
|
|
tok2 = tok2->link();
|
|
// guarded by &&
|
|
if (tok2->varId() == varid && tok2->next()->str() == "&&")
|
|
break;
|
|
tok2 = tok2->previous();
|
|
}
|
|
}
|
|
if (Token::Match(tok2, "[?:]") || tok2->varId() == varid)
|
|
continue;
|
|
|
|
// unknown : this is set by isPointerDeRef if it is
|
|
// uncertain
|
|
bool unknown = _settings->inconclusive;
|
|
|
|
// reassign : is the pointer reassigned like this:
|
|
// tok = tok->next();
|
|
bool reassign = false;
|
|
if (Token::Match(tok1->previous(), "= %varid% .", varid)) {
|
|
const Token *back = tok1->tokAt(-2);
|
|
while (back) {
|
|
if (back->varId() == varid) {
|
|
reassign = true;
|
|
break;
|
|
}
|
|
if (Token::Match(back, "[{};,(]")) {
|
|
break;
|
|
}
|
|
back = back->previous();
|
|
}
|
|
}
|
|
|
|
if (reassign) {
|
|
break;
|
|
} else if (Token::simpleMatch(tok1->tokAt(-2), "* )") &&
|
|
Token::Match(tok1->linkAt(-1)->tokAt(-2), "%varid% = (", tok1->varId())) {
|
|
break;
|
|
} else if (Token::simpleMatch(tok1->tokAt(-3), "* ) (") &&
|
|
Token::Match(tok1->linkAt(-2)->tokAt(-2), "%varid% = (", tok1->varId())) {
|
|
break;
|
|
} else if (Token::Match(tok1->previous(), "&&|%oror%")) {
|
|
break;
|
|
} else if (Token::Match(tok1->tokAt(-2), "&&|%oror% !")) {
|
|
break;
|
|
} else if (CheckNullPointer::isPointerDeRef(tok1, unknown, symbolDatabase)) {
|
|
nullPointerError(tok1, varname, tok->linenr(), inconclusive);
|
|
break;
|
|
} else if (tok1->strAt(-1) == "&") {
|
|
break;
|
|
} else if (tok1->strAt(1) == "=") {
|
|
break;
|
|
}
|
|
}
|
|
|
|
else if (tok1->str() == "{" ||
|
|
tok1->str() == "}")
|
|
break;
|
|
|
|
// label..
|
|
else if (Token::Match(tok1, "%type% :"))
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerByCheckAndDeRef()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
// Check if pointer is NULL and then dereference it..
|
|
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
|
|
if (i->type != Scope::eIf && i->type != Scope::eElseIf && i->type != Scope::eWhile)
|
|
continue;
|
|
if (!i->classDef || i->classDef->isExpandedMacro())
|
|
continue;
|
|
|
|
const Token* const tok = i->type != Scope::eElseIf ? i->classDef->next() : i->classDef->tokAt(2);
|
|
// TODO: investigate false negatives:
|
|
// - handle "while"?
|
|
// - if there are logical operators
|
|
// - if (x) { } else { ... }
|
|
|
|
// If the if-body ends with a unknown macro then bailout
|
|
if (Token::Match(i->classEnd->tokAt(-3), "[;{}] %var% ;") && isUpper(i->classEnd->strAt(-2)))
|
|
continue;
|
|
|
|
// vartok : token for the variable
|
|
const Token *vartok = 0;
|
|
const Token *checkConditionStart = 0;
|
|
if (Token::Match(tok, "( ! %var% )|&&")) {
|
|
vartok = tok->tokAt(2);
|
|
checkConditionStart = vartok->next();
|
|
} else if (Token::Match(tok, "( %var% )|&&")) {
|
|
vartok = tok->next();
|
|
} else if (Token::Match(tok, "( ! ( %var% =")) {
|
|
vartok = tok->tokAt(3);
|
|
if (Token::simpleMatch(tok->tokAt(2)->link(), ") &&"))
|
|
checkConditionStart = tok->tokAt(2)->link();
|
|
} else
|
|
continue;
|
|
|
|
// variable id for pointer
|
|
const unsigned int varid(vartok->varId());
|
|
if (varid == 0)
|
|
continue;
|
|
|
|
// Check if variable is a pointer
|
|
const Variable* var = _tokenizer->getSymbolDatabase()->getVariableFromVarId(varid);
|
|
if (!var || !var->isPointer())
|
|
continue;
|
|
|
|
if (Token::Match(vartok->next(), "&& ( %varid% =", varid))
|
|
continue;
|
|
|
|
// Name and line of the pointer
|
|
const std::string &pointerName = vartok->str();
|
|
const unsigned int linenr = vartok->linenr();
|
|
|
|
// if this is true then it is known that the pointer is null
|
|
bool null = true;
|
|
|
|
// Check the condition (eg. ( !x && x->i )
|
|
if (checkConditionStart) {
|
|
const Token * const conditionEnd = tok->link();
|
|
for (const Token *tok2 = checkConditionStart; tok2 != conditionEnd; tok2 = tok2->next()) {
|
|
// If we hit a || operator, abort
|
|
if (tok2->str() == "||") {
|
|
break;
|
|
}
|
|
// Pointer is used
|
|
else if (Token::Match(tok2, "* %varid%", varid)) {
|
|
nullPointerError(tok2->tokAt(2), pointerName, linenr, false);
|
|
break;
|
|
}
|
|
// Pointer is used
|
|
else if (Token::Match(tok2, "%varid% .", varid)) {
|
|
nullPointerError(tok2, pointerName, linenr, false);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// start token = inside the if-body
|
|
const Token *tok1 = i->classStart;
|
|
|
|
if (Token::Match(tok, "( %var% )|&&")) {
|
|
// pointer might be null
|
|
null = false;
|
|
|
|
// start token = first token after the if/while body
|
|
tok1 = i->classEnd->next();
|
|
if (!tok1)
|
|
continue;
|
|
}
|
|
|
|
unsigned int indentlevel = 0;
|
|
|
|
// Set to true if we would normally bail out the check.
|
|
bool inconclusive = false;
|
|
|
|
// Count { and } for tok2
|
|
for (const Token *tok2 = tok1; tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "{")
|
|
++indentlevel;
|
|
else if (tok2->str() == "}") {
|
|
if (indentlevel == 0)
|
|
break;
|
|
--indentlevel;
|
|
|
|
// calling exit function?
|
|
bool unknown = false;
|
|
if (_tokenizer->IsScopeNoReturn(tok2, &unknown)) {
|
|
if (_settings->inconclusive && unknown)
|
|
inconclusive = true;
|
|
else
|
|
break;
|
|
}
|
|
|
|
if (null && indentlevel == 0) {
|
|
// skip all "else" blocks because they are not executed in this execution path
|
|
while (Token::simpleMatch(tok2, "} else {"))
|
|
tok2 = tok2->linkAt(2);
|
|
null = false;
|
|
}
|
|
}
|
|
|
|
if (tok2->str() == "return" || tok2->str() == "throw") {
|
|
bool unknown = _settings->inconclusive;
|
|
for (; tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
|
|
if (tok2->varId() == varid) {
|
|
if (CheckNullPointer::isPointerDeRef(tok2, unknown, symbolDatabase))
|
|
nullPointerError(tok2, pointerName, linenr, inconclusive);
|
|
else if (unknown)
|
|
nullPointerError(tok2, pointerName, linenr, true);
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
if (Token::Match(tok2, "goto|continue|break|if|switch|for"))
|
|
break;
|
|
|
|
// parameters to sizeof are not dereferenced
|
|
if (Token::Match(tok2, "decltype|sizeof")) {
|
|
if (tok2->strAt(1) != "(")
|
|
tok2 = tok2->next();
|
|
else
|
|
tok2 = tok2->next()->link();
|
|
continue;
|
|
}
|
|
|
|
// function call, check if pointer is dereferenced
|
|
if (Token::Match(tok2, "%var% (")) {
|
|
std::list<const Token *> vars;
|
|
parseFunctionCall(*tok2, vars, 0);
|
|
for (std::list<const Token *>::const_iterator it = vars.begin(); it != vars.end(); ++it) {
|
|
if (Token::Match(*it, "%varid% [,)]", varid)) {
|
|
nullPointerError(*it, pointerName, linenr, inconclusive);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
// calling unknown function (abort/init)..
|
|
else if (Token::simpleMatch(tok2, ") ;") &&
|
|
(Token::Match(tok2->link()->tokAt(-2), "[;{}.] %var% (") ||
|
|
Token::Match(tok2->link()->tokAt(-5), "[;{}] ( * %var% ) ("))) {
|
|
// noreturn function?
|
|
bool unknown = false;
|
|
if (_tokenizer->IsScopeNoReturn(tok2->tokAt(2), &unknown)) {
|
|
if (!unknown || !_settings->inconclusive) {
|
|
break;
|
|
}
|
|
inconclusive = _settings->inconclusive;
|
|
}
|
|
|
|
// init function (global variables)
|
|
if (!var || !(var->isLocal() || var->isArgument()))
|
|
break;
|
|
}
|
|
|
|
if (tok2->varId() == varid) {
|
|
// unknown: this is set to true by isPointerDeRef if
|
|
// the function fails to determine if there
|
|
// is a dereference or not
|
|
bool unknown = _settings->inconclusive;
|
|
|
|
if (Token::Match(tok2->previous(), "[;{}=] %var% = 0 ;"))
|
|
;
|
|
|
|
else if (CheckNullPointer::isPointerDeRef(tok2, unknown, symbolDatabase))
|
|
nullPointerError(tok2, pointerName, linenr, inconclusive);
|
|
|
|
else if (unknown && _settings->inconclusive)
|
|
nullPointerError(tok2, pointerName, linenr, true);
|
|
|
|
else
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
void CheckNullPointer::nullPointer()
|
|
{
|
|
nullPointerAfterLoop();
|
|
nullPointerLinkedList();
|
|
nullPointerStructByDeRefAndChec();
|
|
nullPointerByDeRefAndChec();
|
|
nullPointerByCheckAndDeRef();
|
|
}
|
|
|
|
/** Dereferencing null constant (simplified token list) */
|
|
void CheckNullPointer::nullConstantDereference()
|
|
{
|
|
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
|
|
|
|
for (std::list<Scope>::const_iterator i = symbolDatabase->scopeList.begin(); i != symbolDatabase->scopeList.end(); ++i) {
|
|
if (i->type != Scope::eFunction || !i->classStart)
|
|
continue;
|
|
|
|
const Token *tok = i->classStart;
|
|
|
|
if (i->function && (i->function->type == Function::eConstructor || i->function->type == Function::eCopyConstructor))
|
|
tok = i->function->token; // Check initialization list
|
|
|
|
for (; tok != i->classEnd; tok = tok->next()) {
|
|
if (Token::Match(tok, "sizeof|decltype|typeid ("))
|
|
tok = tok->next()->link();
|
|
|
|
else if (Token::simpleMatch(tok, "* 0")) {
|
|
if (Token::Match(tok->previous(), "return|throw|;|{|}|:|[|(|,") || tok->previous()->isOp() || tok->previous()->isAssignmentOp()) {
|
|
nullPointerError(tok);
|
|
}
|
|
}
|
|
|
|
else if (Token::Match(tok, "0 [") && (tok->previous()->str() != "&" || !Token::Match(tok->next()->link()->next(), "[.(]")))
|
|
nullPointerError(tok);
|
|
|
|
else if (Token::Match(tok->previous(), "!!. %var% (") && (tok->previous()->str() != "::" || tok->strAt(-2) == "std")) {
|
|
if (Token::simpleMatch(tok->tokAt(2), "0 )") && tok->varId()) { // constructor call
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(tok->varId());
|
|
if (var && !var->isPointer() && !var->isArray() && Token::Match(var->typeStartToken(), "std :: string !!::"))
|
|
nullPointerError(tok);
|
|
} else { // function call
|
|
std::list<const Token *> var;
|
|
parseFunctionCall(*tok, var, 0);
|
|
|
|
// is one of the var items a NULL pointer?
|
|
for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it) {
|
|
if (Token::Match(*it, "0 [,)]")) {
|
|
nullPointerError(*it);
|
|
}
|
|
}
|
|
}
|
|
} else if (Token::simpleMatch(tok, "std :: string ( 0 )"))
|
|
nullPointerError(tok);
|
|
|
|
else if (Token::simpleMatch(tok->previous(), ">> 0")) { // Only checking input stream operations is safe here, because otherwise 0 can be an integer as well
|
|
const Token* tok2 = tok->previous(); // Find start of statement
|
|
for (; tok2; tok2 = tok2->previous()) {
|
|
if (Token::Match(tok2->previous(), ";|{|}|:"))
|
|
break;
|
|
}
|
|
if (Token::simpleMatch(tok2, "std :: cin"))
|
|
nullPointerError(tok);
|
|
if (tok2 && tok2->varId() != 0) {
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(tok2->varId());
|
|
if (var && Token::Match(var->typeStartToken(), "std :: istream|ifstream|istringstream|stringstream|fstream|iostream"))
|
|
nullPointerError(tok);
|
|
}
|
|
}
|
|
|
|
unsigned int ovarid = 0;
|
|
if (Token::Match(tok, "0 ==|!= %var%"))
|
|
ovarid = tok->tokAt(2)->varId();
|
|
else if (Token::Match(tok, "%var% ==|!= 0"))
|
|
ovarid = tok->varId();
|
|
else if (Token::Match(tok, "%var% =|+=|+ 0 )|]|,|;|+"))
|
|
ovarid = tok->varId();
|
|
if (ovarid) {
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(ovarid);
|
|
if (var && !var->isPointer() && !var->isArray() && Token::Match(var->typeStartToken(), "std :: string !!::"))
|
|
nullPointerError(tok);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
|
|
/// @addtogroup Checks
|
|
/// @{
|
|
|
|
|
|
/**
|
|
* @brief %Check for null pointer usage (using ExecutionPath)
|
|
*/
|
|
|
|
class Nullpointer : public ExecutionPath {
|
|
public:
|
|
/** Startup constructor */
|
|
Nullpointer(Check *c, const SymbolDatabase* symbolDatabase_) : ExecutionPath(c, 0), symbolDatabase(symbolDatabase_), null(false) {
|
|
}
|
|
|
|
private:
|
|
const SymbolDatabase* symbolDatabase;
|
|
|
|
/** Create checking of specific variable: */
|
|
Nullpointer(Check *c, const unsigned int id, const std::string &name, const SymbolDatabase* symbolDatabase_)
|
|
: ExecutionPath(c, id),
|
|
symbolDatabase(symbolDatabase_),
|
|
varname(name),
|
|
null(false) {
|
|
}
|
|
|
|
/** Copy this check */
|
|
ExecutionPath *copy() {
|
|
return new Nullpointer(*this);
|
|
}
|
|
|
|
/** no implementation => compiler error if used by accident */
|
|
void operator=(const Nullpointer &);
|
|
|
|
/** is other execution path equal? */
|
|
bool is_equal(const ExecutionPath *e) const {
|
|
const Nullpointer *c = static_cast<const Nullpointer *>(e);
|
|
return (varname == c->varname && null == c->null);
|
|
}
|
|
|
|
/** variable name for this check (empty => dummy check) */
|
|
const std::string varname;
|
|
|
|
/** is this variable null? */
|
|
bool null;
|
|
|
|
/** variable is set to null */
|
|
static void setnull(std::list<ExecutionPath *> &checks, const unsigned int varid) {
|
|
std::list<ExecutionPath *>::iterator it;
|
|
for (it = checks.begin(); it != checks.end(); ++it) {
|
|
Nullpointer *c = dynamic_cast<Nullpointer *>(*it);
|
|
if (c && c->varId == varid)
|
|
c->null = true;
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Dereferencing variable. Check if it is safe (if the variable is null there's an error)
|
|
* @param checks Checks
|
|
* @param tok token where dereferencing happens
|
|
*/
|
|
static void dereference(std::list<ExecutionPath *> &checks, const Token *tok) {
|
|
const unsigned int varid(tok->varId());
|
|
|
|
std::list<ExecutionPath *>::iterator it;
|
|
for (it = checks.begin(); it != checks.end(); ++it) {
|
|
Nullpointer *c = dynamic_cast<Nullpointer *>(*it);
|
|
if (c && c->varId == varid && c->null) {
|
|
if ((Token::Match(tok->tokAt(-4), "[=[(,] %var% && * %var% ,|]|)|;|=|%op%") ||
|
|
Token::Match(tok->tokAt(-5), "[=[(,] ! %var% %oror% * %var% ,|]|)|;|=|%op%") ||
|
|
Token::Match(tok->tokAt(-4), "return|case %var% && * %var% ,|:|;|=|%op%") ||
|
|
Token::Match(tok->tokAt(-5), "return|case ! %var% %oror% * %var% ,|:|;|=|%op%")) &&
|
|
tok->tokAt(-3) && (tok->tokAt(-3)->varId() == tok->varId()))
|
|
return;
|
|
|
|
CheckNullPointer *checkNullPointer = dynamic_cast<CheckNullPointer *>(c->owner);
|
|
if (checkNullPointer) {
|
|
checkNullPointer->nullPointerError(tok, c->varname);
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
/** parse tokens */
|
|
const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const {
|
|
if (tok.varId() != 0) {
|
|
// Pointer declaration declaration?
|
|
const Variable* var = symbolDatabase->getVariableFromVarId(tok.varId());
|
|
if (var && var->isPointer() && var->nameToken() == &tok)
|
|
checks.push_back(new Nullpointer(owner, var->varId(), var->name(), symbolDatabase));
|
|
}
|
|
|
|
if (Token::simpleMatch(&tok, "try {")) {
|
|
// Bail out all used variables
|
|
const Token* tok2 = &tok;
|
|
const Token* endtok = tok.linkAt(1);
|
|
for (; tok2 && tok2 != endtok; tok2 = tok2->next()) {
|
|
if (tok2->varId())
|
|
bailOutVar(checks,tok2->varId());
|
|
}
|
|
return tok2;
|
|
}
|
|
|
|
if (Token::Match(&tok, "%var% (")) {
|
|
if (tok.str() == "sizeof" || tok.str() == "typeid")
|
|
return tok.next()->link();
|
|
|
|
// parse usage..
|
|
std::list<const Token *> var;
|
|
CheckNullPointer::parseFunctionCall(tok, var, 0);
|
|
for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
|
|
dereference(checks, *it);
|
|
}
|
|
|
|
else if (Token::simpleMatch(&tok, "( 0 &&"))
|
|
return tok.link();
|
|
|
|
if (tok.varId() != 0) {
|
|
// unknown: if isPointerDeRef fails to determine if there
|
|
// is a dereference this will be set to true.
|
|
bool unknown = owner->inconclusiveFlag();
|
|
bool deref = CheckNullPointer::isPointerDeRef(&tok, unknown, symbolDatabase);
|
|
|
|
if (deref)
|
|
dereference(checks, &tok);
|
|
else if (unknown && owner->inconclusiveFlag())
|
|
dereference(checks, &tok);
|
|
if (Token::Match(tok.previous(), "[;{}=] %var% = 0 ;"))
|
|
setnull(checks, tok.varId());
|
|
else if (!deref &&
|
|
(!tok.previous()->isOp() || tok.previous()->str() == "&") && !tok.previous()->isAssignmentOp() &&
|
|
(!tok.next()->isOp() || tok.next()->str() == ">>"))
|
|
bailOutVar(checks, tok.varId()); // If its possible that the pointers value changes, bail out.
|
|
}
|
|
|
|
else if (tok.str() == "delete") {
|
|
const Token *ret = tok.next();
|
|
if (Token::simpleMatch(ret, "[ ]"))
|
|
ret = ret->tokAt(2);
|
|
if (Token::Match(ret, "%var% ;"))
|
|
return ret->next();
|
|
}
|
|
|
|
else if (tok.str() == "return") {
|
|
bool unknown = owner->inconclusiveFlag();
|
|
const Token* tok2 = &tok;
|
|
for (; tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
|
|
if (tok2->varId()) {
|
|
if (CheckNullPointer::isPointerDeRef(tok2, unknown, symbolDatabase) || unknown)
|
|
dereference(checks, tok2);
|
|
}
|
|
|
|
// If return statement contains "?" then assume there
|
|
// is no dangours dereferencing later
|
|
if (tok2->str() == "?") {
|
|
while (tok2 && tok2->str() != ";")
|
|
tok2 = tok2->next();
|
|
return tok2;
|
|
}
|
|
}
|
|
return tok2;
|
|
}
|
|
|
|
return &tok;
|
|
}
|
|
|
|
/** parse condition. @sa ExecutionPath::parseCondition */
|
|
bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks) {
|
|
for (const Token *tok2 = &tok; tok2; tok2 = tok2->next()) {
|
|
if (tok2->str() == "(" || tok2->str() == ")" || tok2->str() == "&&" || tok2->str() == "||" || tok2->str() == "?")
|
|
break;
|
|
bool unknown = owner->inconclusiveFlag();
|
|
if (tok2->varId() && (CheckNullPointer::isPointerDeRef(tok2, unknown, symbolDatabase) || unknown))
|
|
dereference(checks, tok2);
|
|
}
|
|
|
|
if (Token::Match(&tok, "!| %var% (")) {
|
|
std::list<const Token *> var;
|
|
CheckNullPointer::parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 0);
|
|
for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
|
|
dereference(checks, *it);
|
|
}
|
|
|
|
return ExecutionPath::parseCondition(tok, checks);
|
|
}
|
|
|
|
|
|
void parseLoopBody(const Token *tok, std::list<ExecutionPath *> &checks) const {
|
|
while (tok) {
|
|
if (Token::Match(tok, "{|}|return|goto|break|if"))
|
|
return;
|
|
const Token *next = parse(*tok, checks);
|
|
if (next)
|
|
tok = tok->next();
|
|
}
|
|
}
|
|
|
|
};
|
|
/// @}
|
|
|
|
|
|
void CheckNullPointer::executionPaths()
|
|
{
|
|
// Check for null pointer errors..
|
|
Nullpointer c(this, _tokenizer->getSymbolDatabase());
|
|
checkExecutionPaths(_tokenizer->getSymbolDatabase(), &c);
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerError(const Token *tok)
|
|
{
|
|
reportError(tok, Severity::error, "nullPointer", "Null pointer dereference");
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerError(const Token *tok, const std::string &varname)
|
|
{
|
|
reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference: " + varname);
|
|
}
|
|
|
|
void CheckNullPointer::nullPointerError(const Token *tok, const std::string &varname, const unsigned int line, bool inconclusive)
|
|
{
|
|
const std::string errmsg("Possible null pointer dereference: " + varname + " - otherwise it is redundant to check if " + varname + " is null at line " + MathLib::toString<unsigned int>(line));
|
|
reportError(tok, Severity::error, "nullPointer", errmsg, inconclusive);
|
|
}
|