/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2015 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 "checkuninitvar.h"
#include "mathlib.h"
#include "executionpath.h"
#include "checknullpointer.h" // CheckNullPointer::parseFunctionCall
#include "symboldatabase.h"
#include <algorithm>
#include <map>
#include <cassert>
#include <stack>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace {
CheckUninitVar instance;
}
//---------------------------------------------------------------------------
// Skip [ .. ]
static const Token * skipBrackets(const Token *tok)
{
while (tok && tok->str() == "[")
tok = tok->link()->next();
return tok;
}
/// @addtogroup Checks
/// @{
/**
* @brief %Check that uninitialized variables aren't used (using ExecutionPath)
* */
class UninitVar : public ExecutionPath {
public:
/** Startup constructor */
explicit UninitVar(Check *c, const SymbolDatabase* db, const Library *lib, bool isc)
: ExecutionPath(c, 0), symbolDatabase(db), library(lib), isC(isc), var(0), alloc(false), strncpy_(false), memset_nonzero(false) {
}
private:
/** Create a copy of this check */
ExecutionPath *copy() {
return new UninitVar(*this);
}
/** internal constructor for creating extra checks */
UninitVar(Check *c, const Variable* v, const SymbolDatabase* db, const Library *lib, bool isc)
: ExecutionPath(c, v->declarationId()), symbolDatabase(db), library(lib), isC(isc), var(v), alloc(false), strncpy_(false), memset_nonzero(false) {
}
/** is other execution path equal? */
bool is_equal(const ExecutionPath *e) const {
const UninitVar *c = static_cast<const UninitVar *>(e);
return (var == c->var && alloc == c->alloc && strncpy_ == c->strncpy_ && memset_nonzero == c->memset_nonzero);
}
/** pointer to symbol database */
const SymbolDatabase* symbolDatabase;
/** pointer to library */
const Library *library;
const bool isC;
/** variable for this check */
const Variable* var;
/** is this variable allocated? */
bool alloc;
/** is this variable initialized with strncpy (not always zero-terminated) */
bool strncpy_;
/** is this variable initialized but not zero-terminated (memset) */
bool memset_nonzero;
/** allocating pointer. For example : p = malloc(10); */
static void alloc_pointer(std::list<ExecutionPath *> &checks, unsigned int varid) {
// loop through the checks and perform a allocation if the
// variable id matches
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
if (c->var->isPointer() && !c->var->isArray())
c->alloc = true;
else
bailOutVar(checks, varid);
break;
}
}
}
/** Initializing a pointer value. For example: *p = 0; */
static void init_pointer(std::list<ExecutionPath *> &checks, const Token *tok) {
const unsigned int varid(tok->varId());
if (!varid)
return;
// loop through the checks and perform a initialization if the
// variable id matches
std::list<ExecutionPath *>::iterator it = checks.begin();
while (it != checks.end()) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
if (c->alloc || c->var->isArray()) {
delete c;
checks.erase(it++);
continue;
} else {
use_pointer(checks, tok);
}
}
++it;
}
}
/** Deallocate a pointer. For example: free(p); */
static void dealloc_pointer(std::list<ExecutionPath *> &checks, const Token *tok) {
const unsigned int varid(tok->varId());
if (!varid)
return;
// loop through the checks and perform a deallocation if the
// variable id matches
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
// unallocated pointer variable => error
if (c->var->isPointer() && !c->var->isArray() && !c->alloc) {
CheckUninitVar *checkUninitVar = dynamic_cast<CheckUninitVar *>(c->owner);
if (checkUninitVar) {
checkUninitVar->uninitvarError(tok, c->var->name());
break;
}
}
c->alloc = false;
}
}
}
/**
* Pointer assignment: p = x;
* if p is a pointer and x is an array/pointer then bail out
* \param checks all available checks
* \param tok1 the "p" token
* \param tok2 the "x" token
*/
static void pointer_assignment(std::list<ExecutionPath *> &checks, const Token *tok1, const Token *tok2) {
// Variable id for "left hand side" variable
const unsigned int varid1(tok1->varId());
if (varid1 == 0)
return;
// Variable id for "right hand side" variable
const unsigned int varid2(tok2->varId());
if (varid2 == 0)
return;
std::list<ExecutionPath *>::const_iterator it;
// bail out if first variable is a pointer
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid1 && c->var->isPointer() && !c->var->isArray()) {
bailOutVar(checks, varid1);
break;
}
}
// bail out if second variable is a array/pointer
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid2 && (c->var->isPointer() || c->var->isArray())) {
bailOutVar(checks, varid2);
break;
}
}
}
/** Initialize an array with strncpy. */
static void init_strncpy(std::list<ExecutionPath *> &checks, const Token *tok) {
const unsigned int varid(tok->varId());
if (!varid)
return;
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
c->strncpy_ = true;
}
}
}
/** Initialize an array with memset (not zero). */
static void init_memset_nonzero(std::list<ExecutionPath *> &checks, const Token *tok) {
const unsigned int varid(tok->varId());
if (!varid)
return;
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
c->memset_nonzero = true;
}
}
}
/**
* use - called from the use* functions below.
* @param checks all available checks
* @param tok variable token
* @param mode specific behaviour
* @return if error is found, true is returned
*/
static bool use(std::list<ExecutionPath *> &checks, const Token *tok, const int mode) {
const unsigned int varid(tok->varId());
if (varid == 0)
return false;
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == varid) {
// mode 0 : the variable is used "directly"
// example: .. = var;
// it is ok to read the address of an uninitialized array.
// it is ok to read the address of an allocated pointer
if (mode == 0 && (c->var->isArray() || (c->var->isPointer() && c->alloc)))
continue;
// mode 2 : reading array data with mem.. function. It's ok if the
// array is not null-terminated
if (mode == 2 && c->strncpy_)
continue;
// mode 3 : bad usage of pointer. if it's not a pointer then the usage is ok.
// example: ptr->foo();
if (mode == 3 && (!c->var->isPointer() || c->var->isArray()))
continue;
// mode 4 : using dead pointer is invalid.
if (mode == 4 && (!c->var->isPointer() || c->var->isArray() || c->alloc))
continue;
// mode 5 : reading uninitialized array or pointer is invalid.
if (mode == 5 && (!c->var->isArray() && !c->var->isPointer()))
continue;
CheckUninitVar *checkUninitVar = dynamic_cast<CheckUninitVar *>(c->owner);
if (checkUninitVar) {
if (c->strncpy_ || c->memset_nonzero) {
if (!Token::Match(c->var->typeStartToken(), "char|wchar_t")) {
continue;
}
if (Token::Match(tok->next(), "[")) { // Check if it's not being accessed like: 'str[1]'
continue;
}
checkUninitVar->uninitstringError(tok, c->var->name(), c->strncpy_);
} else if (c->var->isPointer() && !c->var->isArray() && c->alloc)
checkUninitVar->uninitdataError(tok, c->var->name());
else
checkUninitVar->uninitvarError(tok, c->var->name());
return true;
}
}
}
// No error found
return false;
}
/**
* Reading variable. Use this function in situations when it is
* invalid to read the data of the variable but not the address.
* @param checks all available checks
* @param tok variable token
* @return if error is found, true is returned
*/
static bool use(std::list<ExecutionPath *> &checks, const Token *tok) {
return use(checks, tok, 0);
}
/**
* Reading array elements. If the variable is not an array then the usage is ok.
* @param checks all available checks
* @param tok variable token
*/
static void use_array(std::list<ExecutionPath *> &checks, const Token *tok) {
use(checks, tok, 1);
}
/**
* Reading array elements with a "mem.." function. It's ok if the array is not null-terminated.
* @param checks all available checks
* @param tok variable token
*/
static void use_array_mem(std::list<ExecutionPath *> &checks, const Token *tok) {
use(checks, tok, 2);
}
/**
* Bad pointer usage. If the variable is not a pointer then the usage is ok.
* @param checks all available checks
* @param tok variable token
* @return if error is found, true is returned
*/
static bool use_pointer(std::list<ExecutionPath *> &checks, const Token *tok) {
return use(checks, tok, 3);
}
/**
* Using variable.. if it's a dead pointer the usage is invalid.
* @param checks all available checks
* @param tok variable token
* @return if error is found, true is returned
*/
static bool use_dead_pointer(std::list<ExecutionPath *> &checks, const Token *tok) {
return use(checks, tok, 4);
}
/**
* Using variable.. reading from uninitialized array or pointer data is invalid.
* Example: = x[0];
* @param checks all available checks
* @param tok variable token
* @return if error is found, true is returned
*/
static bool use_array_or_pointer_data(std::list<ExecutionPath *> &checks, const Token *tok) {
return use(checks, tok, 5);
}
/**
* Parse right hand side expression in statement
* @param tok2 start token of rhs
* @param checks the execution paths
*/
static void parserhs(const Token *tok2, std::list<ExecutionPath *> &checks) {
// check variable usages in rhs/index
while (nullptr != (tok2 = tok2->next())) {
if (Token::Match(tok2, "[;)=]"))
break;
if (Token::Match(tok2, "%name% ("))
break;
if (Token::Match(tok2, "%name% <") && Token::simpleMatch(tok2->linkAt(1), "> ("))
break;
if (tok2->varId() &&
!Token::Match(tok2->previous(), "&|::") &&
!Token::simpleMatch(tok2->tokAt(-2), "& (") &&
!Token::Match(tok2->tokAt(1), ")| =")) {
// Multiple assignments..
if (Token::Match(tok2->next(), ".|[")) {
const Token * tok3 = tok2;
while (tok3) {
if (Token::Match(tok3->next(), ". %name%"))
tok3 = tok3->tokAt(2);
else if (tok3->strAt(1) == "[")
tok3 = tok3->next()->link();
else
break;
}
if (tok3 && tok3->strAt(1) == "=")
continue;
}
bool foundError;
if (tok2->previous()->str() == "*" || tok2->next()->str() == "[")
foundError = use_array_or_pointer_data(checks, tok2);
else
foundError = use(checks, tok2);
// prevent duplicate error messages
if (foundError) {
bailOutVar(checks, tok2->varId());
}
}
}
}
/** parse tokens. @sa ExecutionPath::parse */
const Token *parse(const Token &tok, std::list<ExecutionPath *> &checks) const {
// Variable declaration..
if (Token::Match(&tok, "%var% [[;]")) {
const Variable* var2 = tok.variable();
if (var2 && var2->nameToken() == &tok && !var2->isStatic() && !var2->isExtern() && !Token::simpleMatch(tok.linkAt(1), "] [")) {
if (tok.linkAt(1)) { // array
const Token* endtok = tok.next();
while (endtok->link())
endtok = endtok->link()->next();
if (endtok->str() != ";")
return &tok;
}
const Scope* parent = var2->scope()->nestedIn;
while (parent) {
for (std::list<Variable>::const_iterator j = parent->varlist.begin(); j != parent->varlist.end(); ++j) {
if (j->name() == var2->name()) {
ExecutionPath::bailOutVar(checks, j->declarationId()); // If there is a variable with the same name in other scopes, this might cause false positives, if there are unexpanded macros
break;
}
}
parent = parent->nestedIn;
}
if (var2->isPointer())
checks.push_back(new UninitVar(owner, var2, symbolDatabase, library, isC));
else if (var2->typeEndToken()->str() != ">") {
bool stdtype = var2->typeStartToken()->isStandardType(); // TODO: change to isC to handle unknown types better
if (stdtype && (!var2->isArray() || var2->nameToken()->linkAt(1)->strAt(1) == ";"))
checks.push_back(new UninitVar(owner, var2, symbolDatabase, library, isC));
}
return &tok;
}
}
if (tok.str() == "return") {
// is there assignment or ternary operator in the return statement?
bool assignment = false;
for (const Token *tok2 = tok.next(); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
if (tok2->str() == "=" || (!isC && tok2->str() == ">>") || Token::Match(tok2, "(|, &")) {
assignment = true;
break;
}
if (Token::Match(tok2, "[(,] &| %var% [,)]")) {
tok2 = tok2->next();
if (!tok2->isName())
tok2 = tok2->next();
ExecutionPath::bailOutVar(checks, tok2->varId());
}
}
if (!assignment) {
for (const Token *tok2 = tok.next(); tok2 && tok2->str() != ";"; tok2 = tok2->next()) {
if (tok2->isName() && tok2->strAt(1) == "(")
tok2 = tok2->next()->link();
else if (tok2->varId())
use(checks, tok2);
}
}
}
if (tok.varId()) {
// array variable passed as function parameter..
if (Token::Match(tok.previous(), "[(,] %var% [+-,)]")) {
// #4896 : This checking was removed because of FP,
// the new uninitvar checking is used instead to catch
// these errors.
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
// Used..
if (Token::Match(tok.previous(), "[[(,+-*/|=] %var% ]|)|,|;|%op%") && !tok.next()->isAssignmentOp()) {
// Taking address of array..
std::list<ExecutionPath *>::const_iterator it;
for (it = checks.begin(); it != checks.end(); ++it) {
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varId == tok.varId()) {
if (c->var->isArray() || c->alloc)
bailOutVar(checks, tok.varId());
break;
}
}
// initialize reference variable
if (Token::Match(tok.tokAt(-3), "& %var% ="))
bailOutVar(checks, tok.varId());
else
use(checks, &tok);
return &tok;
}
if ((tok.previous() && tok.previous()->type() == Token::eIncDecOp) || (tok.next() && tok.next()->type() == Token::eIncDecOp)) {
use(checks, &tok);
return &tok;
}
if (Token::Match(tok.previous(), "[;{}] %name% [=[.]")) {
if (tok.next()->str() == ".") {
if (Token::Match(&tok, "%name% . %name% (")) {
const Function *function = tok.tokAt(2)->function();
if (function && function->isStatic())
return &tok;
}
if (use_dead_pointer(checks, &tok)) {
return &tok;
}
} else {
const Token *tok2 = tok.next();
if (tok2->str() == "[") {
const Token *tok3 = tok2->link();
while (Token::simpleMatch(tok3, "] ["))
tok3 = tok3->next()->link();
// Possible initialization
if (Token::simpleMatch(tok3, "] >>"))
return &tok;
if (Token::simpleMatch(tok3, "] =")) {
if (use_dead_pointer(checks, &tok)) {
return &tok;
}
parserhs(tok2, checks);
tok2 = tok3->next();
}
}
parserhs(tok2, checks);
}
// pointer aliasing?
if (Token::Match(tok.tokAt(2), "%name% ;")) {
pointer_assignment(checks, &tok, tok.tokAt(2));
}
}
if (tok.strAt(1) == "(") {
use_pointer(checks, &tok);
}
if (Token::Match(tok.tokAt(-2), "[;{}] *")) {
if (tok.strAt(1) == "=") {
// is the pointer used in the rhs?
bool used = false;
for (const Token *tok2 = tok.tokAt(2); tok2; tok2 = tok2->next()) {
if (Token::Match(tok2, "[,;=(]"))
break;
else if (Token::Match(tok2, "* %varid%", tok.varId())) {
used = true;
break;
}
}
if (used)
use_pointer(checks, &tok);
else
init_pointer(checks, &tok);
} else {
use_pointer(checks, &tok);
}
return &tok;
}
if (Token::Match(tok.next(), "= malloc|kmalloc") || Token::simpleMatch(tok.next(), "= new char [") ||
(Token::Match(tok.next(), "= %name% (") && library->returnuninitdata.find(tok.strAt(2)) != library->returnuninitdata.end())) {
alloc_pointer(checks, tok.varId());
if (tok.strAt(3) == "(")
return tok.tokAt(3);
}
else if ((!isC && (Token::Match(tok.previous(), "<<|>>") || Token::Match(tok.previous(), "[;{}] %name% <<"))) ||
tok.strAt(1) == "=") {
// TODO: Don't bail out for "<<" and ">>" if these are
// just computations
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
if (tok.strAt(1) == "[" && tok.next()->link()) {
const Token *tok2 = tok.next()->link();
if (tok2->strAt(1) == "=") {
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
}
if (tok.strAt(-1) == "delete" ||
Token::simpleMatch(tok.tokAt(-3), "delete [ ]")) {
dealloc_pointer(checks, &tok);
return &tok;
}
}
if (Token::Match(&tok, "%name% (")) {
// sizeof/typeof doesn't dereference. A function name that is all uppercase
// might be an unexpanded macro that uses sizeof/typeof
if (Token::Match(&tok, "sizeof|typeof ("))
return tok.next()->link();
// deallocate pointer
if (Token::Match(&tok, "free|kfree|fclose ( %var% )") ||
Token::Match(&tok, "realloc ( %name%")) {
dealloc_pointer(checks, tok.tokAt(2));
if (tok.str() == "realloc")
ExecutionPath::bailOutVar(checks, tok.tokAt(2)->varId());
return tok.tokAt(3);
}
// parse usage..
{
std::list<const Token *> var1;
CheckNullPointer::parseFunctionCall(tok, var1, library, 1);
for (std::list<const Token *>::const_iterator it = var1.begin(); it != var1.end(); ++it) {
// does iterator point at first function parameter?
const bool firstPar(*it == tok.tokAt(2));
// is function memset/memcpy/etc?
if (tok.str().compare(0,3,"mem") == 0)
use_array_mem(checks, *it);
// second parameter for strncpy/strncat/etc
else if (!firstPar && tok.str().compare(0,4,"strn") == 0)
use_array_mem(checks, *it);
else
use_array(checks, *it);
use_dead_pointer(checks, *it);
}
// Using uninitialized pointer is bad if using null pointer is bad
std::list<const Token *> var2;
CheckNullPointer::parseFunctionCall(tok, var2, library, 0);
for (std::list<const Token *>::const_iterator it = var2.begin(); it != var2.end(); ++it) {
if (std::find(var1.begin(), var1.end(), *it) == var1.end())
use_dead_pointer(checks, *it);
}
}
// strncpy doesn't null-terminate first parameter
if (Token::Match(&tok, "strncpy ( %name% ,")) {
if (Token::Match(tok.tokAt(4), "%str% ,")) {
if (Token::Match(tok.tokAt(6), "%num% )")) {
const std::size_t len = Token::getStrLength(tok.tokAt(4));
const MathLib::bigint sz = MathLib::toLongNumber(tok.strAt(6));
if (sz >= 0 && len >= static_cast<unsigned long>(sz)) {
init_strncpy(checks, tok.tokAt(2));
return tok.next()->link();
}
}
} else {
init_strncpy(checks, tok.tokAt(2));
return tok.next()->link();
}
}
// memset (not zero terminated)..
if (Token::Match(&tok, "memset ( %name% , !!0 , %num% )")) {
init_memset_nonzero(checks, tok.tokAt(2));
return tok.next()->link();
}
if (Token::Match(&tok, "asm ( %str% )")) {
ExecutionPath::bailOut(checks);
return &tok;
}
// is the variable passed as a parameter to some function?
unsigned int parlevel = 0;
std::set<unsigned int> bailouts;
for (const Token *tok2 = tok.next(); tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")") {
if (parlevel <= 1)
break;
--parlevel;
}
else if (Token::Match(tok2, "sizeof|typeof (")) {
tok2 = tok2->next()->link();
if (!tok2)
break;
}
// ticket #2367 : unexpanded macro that uses sizeof|typeof?
else if (Token::Match(tok2, "%type% (") && tok2->isUpperCaseName()) {
tok2 = tok2->next()->link();
if (!tok2)
break;
}
else if (tok2->varId()) {
if (Token::Match(tok2->tokAt(-2), "[(,] *") || Token::Match(tok2->next(), ". %name%")) {
// find function call..
const Token *functionCall = tok2;
while (nullptr != (functionCall = functionCall ? functionCall->previous() : 0)) {
if (functionCall->str() == "(")
break;
if (functionCall->str() == ")")
functionCall = functionCall->link();
}
functionCall = functionCall ? functionCall->previous() : 0;
if (functionCall) {
if (functionCall->isName() && !functionCall->isUpperCaseName() && use_dead_pointer(checks, tok2))
ExecutionPath::bailOutVar(checks, tok2->varId());
}
}
// it is possible that the variable is initialized here
if (Token::Match(tok2->previous(), "[(,] %var% [,)]"))
bailouts.insert(tok2->varId());
// array initialization..
if (Token::Match(tok2->previous(), "[,(] %var% [+-]")) {
// if var is array, bailout
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it) {
if ((*it)->varId == tok2->varId()) {
const UninitVar *c = dynamic_cast<const UninitVar *>(*it);
if (c && (c->var->isArray() || (c->var->isPointer() && c->alloc)))
bailouts.insert(tok2->varId());
break;
}
}
}
}
}
for (std::set<unsigned int>::const_iterator it = bailouts.begin(); it != bailouts.end(); ++it)
ExecutionPath::bailOutVar(checks, *it);
}
// function call via function pointer
if (Token::Match(&tok, "( * %name% ) (") ||
(Token::Match(&tok, "( *| %name% .|::") && Token::Match(tok.link()->tokAt(-2), ".|:: %name% ) ("))) {
// is the variable passed as a parameter to some function?
const Token *tok2 = tok.link()->next();
for (const Token* const end2 = tok2->link(); tok2 != end2; tok2 = tok2->next()) {
if (tok2->varId()) {
// it is possible that the variable is initialized here
ExecutionPath::bailOutVar(checks, tok2->varId());
}
}
}
if (tok.str() == "return") {
// Todo: if (!array && ..
if (Token::Match(tok.next(), "%name% ;")) {
use(checks, tok.next());
} else if (Token::Match(tok.next(), "%name% [")) {
use_array_or_pointer_data(checks, tok.next());
}
}
if (tok.varId()) {
if (tok.strAt(-1) == "=") {
if (Token::Match(tok.tokAt(-3), "& %var% =")) {
bailOutVar(checks, tok.varId());
return &tok;
}
if (!Token::Match(tok.tokAt(-3), ". %name% =")) {
if (!Token::Match(tok.tokAt(-3), "[;{}] %name% =")) {
use(checks, &tok);
return &tok;
}
const unsigned int varid2 = tok.tokAt(-2)->varId();
if (varid2) {
{
use(checks, &tok);
return &tok;
}
}
}
}
if (tok.strAt(1) == ".") {
bailOutVar(checks, tok.varId());
return &tok;
}
if (tok.strAt(1) == "[") {
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
if (Token::Match(tok.tokAt(-2), "[,(=] *")) {
use_pointer(checks, &tok);
return &tok;
}
if (tok.strAt(-1) == "&") {
ExecutionPath::bailOutVar(checks, tok.varId());
}
}
// Parse "for"
if (Token::Match(&tok, "[;{}] for (")) {
// initialized variables
std::set<unsigned int> varid1;
varid1.insert(0);
// Parse token
const Token *tok2;
// parse setup
for (tok2 = tok.tokAt(3); tok2 != tok.link(); tok2 = tok2->next()) {
if (tok2->str() == ";")
break;
if (tok2->varId())
varid1.insert(tok2->varId());
}
if (tok2 == tok.link())
return &tok;
// parse condition
if (Token::Match(tok2, "; %var% <|<=|>=|> %num% ;")) {
// If the variable hasn't been initialized then call "use"
if (varid1.find(tok2->next()->varId()) == varid1.end())
use(checks, tok2->next());
}
// goto stepcode
tok2 = tok2->next();
while (tok2 && tok2->str() != ";")
tok2 = tok2->next();
// parse the stepcode
if (Token::Match(tok2, "; ++|-- %var% ) {") ||
Token::Match(tok2, "; %var% ++|-- ) {")) {
// get id of variable..
unsigned int varid = tok2->next()->varId();
if (!varid)
varid = tok2->tokAt(2)->varId();
// Check that the variable hasn't been initialized and
// that it isn't initialized in the body..
if (varid1.find(varid) == varid1.end()) {
for (const Token *tok3 = tok2->tokAt(5); tok3 && tok3 != tok2->linkAt(4); tok3 = tok3->next()) {
if (tok3->varId() == varid) {
varid = 0; // variable is used.. maybe it's initialized. clear the variable id.
break;
}
}
// If the variable isn't initialized in the body call "use"
if (varid != 0) {
// goto variable
tok2 = tok2->next();
if (!tok2->varId())
tok2 = tok2->next();
// call "use"
use(checks, tok2);
}
}
}
}
return &tok;
}
bool parseCondition(const Token &tok, std::list<ExecutionPath *> &checks) {
if (tok.varId() && Token::Match(&tok, "%name% <|<=|==|!=|)"))
use(checks, &tok);
else if (Token::Match(&tok, "!| %name% [") && !Token::simpleMatch(skipBrackets(tok.next()), "="))
use_array_or_pointer_data(checks, tok.str() == "!" ? tok.next() : &tok);
else if (Token::Match(&tok, "!| %name% (")) {
const Token * const ftok = (tok.str() == "!") ? tok.next() : &tok;
std::list<const Token *> var1;
CheckNullPointer::parseFunctionCall(*ftok, var1, library, 1);
for (std::list<const Token *>::const_iterator it = var1.begin(); it != var1.end(); ++it) {
// is function memset/memcpy/etc?
if (ftok->str().compare(0,3,"mem") == 0)
use_array_mem(checks, *it);
else
use_array(checks, *it);
}
}
else if (Token::Match(&tok, "! %name% )")) {
use(checks, &tok);
return false;
}
return ExecutionPath::parseCondition(tok, checks);
}
void parseLoopBody(const Token *tok, std::list<ExecutionPath *> &checks) const {
while (tok) {
if (tok->str() == "{" || tok->str() == "}" || tok->str() == "for")
return;
if (Token::simpleMatch(tok, "if (")) {
// bail out all variables that are used in the condition
const Token* const end2 = tok->linkAt(1);
for (const Token *tok2 = tok->tokAt(2); tok2 != end2; tok2 = tok2->next()) {
if (tok2->varId())
ExecutionPath::bailOutVar(checks, tok2->varId());
}
}
const Token *next = parse(*tok, checks);
tok = next->next();
}
}
public:
static void analyseFunctions(const Token * const tokens, std::set<std::string> &func) {
for (const Token *tok = tokens; tok; tok = tok->next()) {
if (tok->str() == "{") {
tok = tok->link();
continue;
}
if (tok->str() != "::" && Token::Match(tok->next(), "%name% ( %type%")) {
if (!Token::Match(tok->linkAt(2), ") [{;]"))
continue;
const Token *tok2 = tok->tokAt(3);
while (tok2 && tok2->str() != ")") {
if (tok2->str() == ",")
tok2 = tok2->next();
if (Token::Match(tok2, "%type% %name% ,|)") && tok2->isStandardType()) {
tok2 = tok2->tokAt(2);
continue;
}
if (tok2->isStandardType() && Token::Match(tok2, "%type% & %name% ,|)")) {
const unsigned int varid(tok2->tokAt(2)->varId());
// flags for read/write
bool r = false, w = false;
// check how the variable is used in the function
unsigned int indentlevel = 0;
for (const Token *tok3 = tok2; tok3; tok3 = tok3->next()) {
if (tok3->str() == "{")
++indentlevel;
else if (tok3->str() == "}") {
if (indentlevel <= 1)
break;
--indentlevel;
} else if (indentlevel == 0 && tok3->str() == ";")
break;
else if (indentlevel >= 1 && tok3->varId() == varid) {
if (tok3->previous()->type() == Token::eIncDecOp ||
tok3->next()->type() == Token::eIncDecOp) {
r = true;
}
else {
w = true;
break;
}
}
}
if (!r || w)
break;
tok2 = tok2->tokAt(3);
continue;
}
if (Token::Match(tok2, "const %type% &|*| const| %name% ,|)") && tok2->next()->isStandardType()) {
tok2 = tok2->tokAt(3);
while (tok2->isName())
tok2 = tok2->next();
continue;
}
if (Token::Match(tok2, "const %type% %name% [ ] ,|)") && tok2->next()->isStandardType()) {
tok2 = tok2->tokAt(5);
continue;
}
/// @todo enable this code. if pointer is written in function then dead pointer is invalid but valid pointer is ok.
/*
if (Token::Match(tok2, "const| struct| %type% * %name% ,|)"))
{
while (tok2->isName())
tok2 = tok2->next();
tok2 = tok2->tokAt(2);
continue;
}
*/
break;
}
// found simple function..
if (tok2 && tok2->link() == tok->tokAt(2))
func.insert(tok->next()->str());
}
}
}
};
/// @}
Check::FileInfo *CheckUninitVar::getFileInfo(const Tokenizer *tokenizer, const Settings *settings) const
{
(void)settings;
MyFileInfo * mfi = new MyFileInfo;
analyseFunctions(tokenizer, mfi->uvarFunctions);
// TODO: add suspicious function calls
return mfi;
}
void CheckUninitVar::analyseWholeProgram(const std::list<Check::FileInfo*> &fileInfo, ErrorLogger &errorLogger)
{
(void)fileInfo;
(void)errorLogger;
}
void CheckUninitVar::analyseFunctions(const Tokenizer *tokenizer, std::set<std::string> &f) const
{
UninitVar::analyseFunctions(tokenizer->tokens(), f);
}
void CheckUninitVar::executionPaths()
{
// check if variable is accessed uninitialized..
UninitVar c(this, _tokenizer->getSymbolDatabase(), &_settings->library, _tokenizer->isC());
checkExecutionPaths(_tokenizer->getSymbolDatabase(), &c);
}
void CheckUninitVar::check()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
// check every executable scope
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (scope->isExecutable()) {
checkScope(&*scope);
}
}
}
void CheckUninitVar::checkScope(const Scope* scope)
{
for (std::list<Variable>::const_iterator i = scope->varlist.begin(); i != scope->varlist.end(); ++i) {
if ((_tokenizer->isCPP() && i->type() && !i->isPointer() && i->type()->needInitialization != Type::True) ||
i->isStatic() || i->isExtern() || i->isArray() || i->isReference())
continue;
// don't warn for try/catch exception variable
if (i->isThrow())
continue;
if (i->nameToken()->strAt(1) == "(" || i->nameToken()->strAt(1) == "{")
continue;
if (Token::Match(i->nameToken(), "%name% =")) { // Variable is initialized, but Rhs might be not
checkRhs(i->nameToken(), *i, NO_ALLOC, "");
continue;
}
if (Token::Match(i->nameToken(), "%name% ) (") && Token::simpleMatch(i->nameToken()->linkAt(2), ") =")) { // Function pointer is initialized, but Rhs might be not
checkRhs(i->nameToken()->linkAt(2)->next(), *i, NO_ALLOC, "");
continue;
}
bool stdtype = _tokenizer->isC();
const Token* tok = i->typeStartToken();
for (; tok && tok->str() != ";" && tok->str() != "<"; tok = tok->next()) {
if (tok->isStandardType())
stdtype = true;
}
while (tok && tok->str() != ";")
tok = tok->next();
if (!tok)
continue;
if (stdtype || i->isPointer()) {
Alloc alloc = NO_ALLOC;
checkScopeForVariable(tok, *i, nullptr, nullptr, &alloc, "");
}
if (i->type())
checkStruct(tok, *i);
}
if (scope->function) {
for (unsigned int i = 0; i < scope->function->argCount(); i++) {
const Variable *arg = scope->function->getArgumentVar(i);
if (arg && arg->declarationId() && Token::Match(arg->typeStartToken(), "struct| %type% * %name% [,)]")) {
// Treat the pointer as initialized until it is assigned by malloc
for (const Token *tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
if (Token::Match(tok, "[;{}] %varid% = %name% (", arg->declarationId()) &&
_settings->library.returnuninitdata.count(tok->strAt(3)) == 1U) {
if (arg->typeStartToken()->str() == "struct")
checkStruct(tok, *arg);
else if (arg->typeStartToken()->isStandardType()) {
Alloc alloc = NO_ALLOC;
checkScopeForVariable(tok->next(), *arg, nullptr, nullptr, &alloc, "");
}
}
}
}
}
}
}
void CheckUninitVar::checkStruct(const Token *tok, const Variable &structvar)
{
const Token *typeToken = structvar.typeStartToken();
if (typeToken->str() == "struct")
typeToken = typeToken->next();
const SymbolDatabase * symbolDatabase = _tokenizer->getSymbolDatabase();
for (std::size_t j = 0U; j < symbolDatabase->classAndStructScopes.size(); ++j) {
const Scope *scope2 = symbolDatabase->classAndStructScopes[j];
if (scope2->className == typeToken->str() && scope2->numConstructors == 0U) {
for (std::list<Variable>::const_iterator it = scope2->varlist.begin(); it != scope2->varlist.end(); ++it) {
const Variable &var = *it;
if (var.hasDefault() || var.isArray() || (!_tokenizer->isC() && var.isClass() && (!var.type() || var.type()->needInitialization != Type::True)))
continue;
// is the variable declared in a inner union?
bool innerunion = false;
for (std::list<Scope>::const_iterator it2 = symbolDatabase->scopeList.begin(); it2 != symbolDatabase->scopeList.end(); ++it2) {
const Scope &innerScope = *it2;
if (innerScope.type == Scope::eUnion && innerScope.nestedIn == scope2) {
if (var.typeStartToken()->linenr() >= innerScope.classStart->linenr() &&
var.typeStartToken()->linenr() <= innerScope.classEnd->linenr()) {
innerunion = true;
break;
}
}
}
if (!innerunion) {
Alloc alloc = NO_ALLOC;
const Token *tok2 = tok;
if (tok->str() == "}")
tok2 = tok2->next();
checkScopeForVariable(tok2, structvar, nullptr, nullptr, &alloc, var.name());
}
}
}
}
}
static void conditionAlwaysTrueOrFalse(const Token *tok, const std::map<unsigned int, int> &variableValue, bool *alwaysTrue, bool *alwaysFalse)
{
assert(Token::simpleMatch(tok, "if ("));
const Token *vartok = tok->tokAt(2);
const bool NOT(vartok->str() == "!");
if (NOT)
vartok = vartok->next();
while (Token::Match(vartok, "%name% . %name%"))
vartok = vartok->tokAt(2);
std::map<unsigned int, int>::const_iterator it = variableValue.find(vartok->varId());
if (it == variableValue.end())
return;
// always true
if (Token::Match(vartok, "%name% %oror%|)")) {
if (NOT)
*alwaysTrue = bool(it->second == 0);
else
*alwaysTrue = bool(it->second != 0);
} else if (Token::Match(vartok, "%name% == %num% %or%|)")) {
*alwaysTrue = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
} else if (Token::Match(vartok, "%name% != %num% %or%|)")) {
*alwaysTrue = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
}
// always false
if (Token::Match(vartok, "%name% &&|)")) {
if (NOT)
*alwaysFalse = bool(it->second != 0);
else
*alwaysFalse = bool(it->second == 0);
} else if (Token::Match(vartok, "%name% == %num% &&|)")) {
*alwaysFalse = bool(it->second != MathLib::toLongNumber(vartok->strAt(2)));
} else if (Token::Match(vartok, "%name% != %num% &&|)")) {
*alwaysFalse = bool(it->second == MathLib::toLongNumber(vartok->strAt(2)));
}
}
bool CheckUninitVar::checkScopeForVariable(const Token *tok, const Variable& var, bool * const possibleInit, bool * const noreturn, Alloc* const alloc, const std::string &membervar)
{
const bool suppressErrors(possibleInit && *possibleInit);
if (possibleInit)
*possibleInit = false;
unsigned int number_of_if = 0;
if (var.declarationId() == 0U)
return true;
// variable values
std::map<unsigned int, int> variableValue;
static const int NOT_ZERO = (1<<30); // special variable value
for (; tok; tok = tok->next()) {
// End of scope..
if (tok->str() == "}") {
if (number_of_if && possibleInit)
*possibleInit = true;
// might be a noreturn function..
if (_tokenizer->IsScopeNoReturn(tok)) {
if (noreturn)
*noreturn = true;
return false;
}
break;
}
// Unconditional inner scope or try..
if (tok->str() == "{" && Token::Match(tok->previous(), ";|{|}|try")) {
if (checkScopeForVariable(tok->next(), var, possibleInit, noreturn, alloc, membervar))
return true;
tok = tok->link();
continue;
}
// assignment with nonzero constant..
if (Token::Match(tok->previous(), "[;{}] %var% = - %name% ;"))
variableValue[tok->varId()] = NOT_ZERO;
// Inner scope..
else if (Token::simpleMatch(tok, "if (")) {
bool alwaysTrue = false;
bool alwaysFalse = false;
conditionAlwaysTrueOrFalse(tok, variableValue, &alwaysTrue, &alwaysFalse);
// initialization / usage in condition..
if (!alwaysTrue && checkIfForWhileHead(tok->next(), var, suppressErrors, bool(number_of_if == 0), *alloc, membervar))
return true;
// checking if a not-zero variable is zero => bail out
unsigned int condVarId = 0, condVarValue = 0;
if (Token::Match(tok, "if ( %name% )")) {
std::map<unsigned int,int>::const_iterator it = variableValue.find(tok->tokAt(2)->varId());
if (it != variableValue.end() && it->second == NOT_ZERO)
return true; // this scope is not fully analysed => return true
else {
condVarId = tok->tokAt(2)->varId();
condVarValue = NOT_ZERO;
}
}
// goto the {
tok = tok->next()->link()->next();
if (!tok)
break;
if (tok->str() == "{") {
bool possibleInitIf(number_of_if > 0 || suppressErrors);
bool noreturnIf = false;
const bool initif = !alwaysFalse && checkScopeForVariable(tok->next(), var, &possibleInitIf, &noreturnIf, alloc, membervar);
// bail out for such code:
// if (a) x=0; // conditional initialization
// if (b) return; // cppcheck doesn't know if b can be false when a is false.
// x++; // it's possible x is always initialized
if (!alwaysTrue && noreturnIf && number_of_if > 0) {
if (_settings->debugwarnings) {
std::string condition;
for (const Token *tok2 = tok->linkAt(-1); tok2 != tok; tok2 = tok2->next()) {
condition += tok2->str();
if (tok2->isName() && tok2->next()->isName())
condition += ' ';
}
reportError(tok, Severity::debug, "debug", "bailout uninitialized variable checking for '" + var.name() + "'. can't determine if this condition can be false when previous condition is false: " + condition);
}
return true;
}
if (alwaysTrue && noreturnIf)
return true;
std::map<unsigned int, int> varValueIf;
if (!alwaysFalse && !initif && !noreturnIf) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %name% = - %name% ;"))
varValueIf[tok2->next()->varId()] = NOT_ZERO;
else if (Token::Match(tok2, "[;{}.] %name% = %num% ;"))
varValueIf[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
}
}
if (initif && condVarId > 0U)
variableValue[condVarId] = condVarValue ^ NOT_ZERO;
// goto the }
tok = tok->link();
if (!Token::simpleMatch(tok, "} else {")) {
if (initif || possibleInitIf) {
++number_of_if;
if (number_of_if >= 2)
return true;
}
} else {
// goto the {
tok = tok->tokAt(2);
bool possibleInitElse(number_of_if > 0 || suppressErrors);
bool noreturnElse = false;
const bool initelse = !alwaysTrue && checkScopeForVariable(tok->next(), var, &possibleInitElse, nullptr, alloc, membervar);
std::map<unsigned int, int> varValueElse;
if (!alwaysTrue && !initelse && !noreturnElse) {
for (const Token *tok2 = tok; tok2 && tok2 != tok->link(); tok2 = tok2->next()) {
if (Token::Match(tok2, "[;{}.] %var% = - %name% ;"))
varValueElse[tok2->next()->varId()] = NOT_ZERO;
else if (Token::Match(tok2, "[;{}.] %var% = %num% ;"))
varValueElse[tok2->next()->varId()] = (int)MathLib::toLongNumber(tok2->strAt(3));
}
}
if (initelse && condVarId > 0U && !noreturnIf && !noreturnElse)
variableValue[condVarId] = condVarValue;
// goto the }
tok = tok->link();
if ((alwaysFalse || initif || noreturnIf) &&
(alwaysTrue || initelse || noreturnElse))
return true;
if ((initif || initelse || possibleInitElse) && !noreturnIf && !noreturnElse) {
++number_of_if;
variableValue.insert(varValueIf.begin(), varValueIf.end());
variableValue.insert(varValueElse.begin(), varValueElse.end());
}
}
}
}
// = { .. }
else if (Token::simpleMatch(tok, "= {")) {
// end token
const Token *end = tok->next()->link();
// If address of variable is taken in the block then bail out
if (Token::findmatch(tok->tokAt(2), "& %varid%", end, var.declarationId()))
return true;
// Skip block
tok = end;
continue;
}
// skip sizeof / offsetof
if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
tok = tok->next()->link();
// for/while..
else if (Token::Match(tok, "for|while (") || Token::simpleMatch(tok, "do {")) {
const bool forwhile = Token::Match(tok, "for|while (");
// is variable initialized in for-head (don't report errors yet)?
if (forwhile && checkIfForWhileHead(tok->next(), var, true, false, *alloc, membervar))
return true;
// goto the {
const Token *tok2 = forwhile ? tok->next()->link()->next() : tok->next();
if (tok2 && tok2->str() == "{") {
bool init = checkLoopBody(tok2, var, *alloc, membervar, (number_of_if > 0) || suppressErrors);
// variable is initialized in the loop..
if (init)
return true;
// is variable used in for-head?
bool initcond = false;
if (!suppressErrors) {
const Token *startCond = forwhile ? tok->next() : tok->next()->link()->tokAt(2);
initcond = checkIfForWhileHead(startCond, var, false, bool(number_of_if == 0), *alloc, membervar);
}
// goto "}"
tok = tok2->link();
// do-while => goto ")"
if (!forwhile) {
// Assert that the tokens are '} while ('
if (!Token::simpleMatch(tok, "} while (")) {
if (_settings->debugwarnings)
reportError(tok,Severity::debug,"","assertion failed '} while ('");
break;
}
// Goto ')'
tok = tok->linkAt(2);
if (!tok)
// bailout : invalid code / bad tokenizer
break;
if (initcond)
// variable is initialized in while-condition
return true;
}
}
}
// Unknown or unhandled inner scope
else if (Token::simpleMatch(tok, ") {") || (Token::Match(tok, "%name% {") && tok->str() != "try")) {
if (tok->str() == "struct" || tok->str() == "union") {
tok = tok->linkAt(1);
continue;
}
return true;
}
// bailout if there is ({
if (Token::simpleMatch(tok, "( {")) {
return true;
}
// bailout if there is assembler code or setjmp
if (Token::Match(tok, "asm|setjmp (")) {
return true;
}
// bailout on ternary operator. TODO: This can be solved much better. For example, if the variable is not accessed in the branches of the ternary operator, we could just continue.
if (tok->str() == "?") {
return true;
}
if (Token::Match(tok, "return|break|continue|throw|goto")) {
if (noreturn)
*noreturn = true;
while (tok && tok->str() != ";") {
// variable is seen..
if (tok->varId() == var.declarationId()) {
if (!membervar.empty()) {
if (Token::Match(tok, "%name% . %name% ;|%cop%") && tok->strAt(2) == membervar)
uninitStructMemberError(tok, tok->str() + "." + membervar);
else
return true;
}
// Use variable
else if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc)) {
if (*alloc != NO_ALLOC)
uninitdataError(tok, tok->str());
else
uninitvarError(tok, tok->str());
}
else
// assume that variable is assigned
return true;
}
else if (Token::Match(tok, "sizeof|typeof|offsetof|decltype ("))
tok = tok->linkAt(1);
else if (tok->str() == "?")
// TODO: False negatives when "?:" is used.
// Fix the tokenizer and then remove this bailout.
// The tokenizer should replace "return x?y:z;" with "if(x)return y;return z;"
return true;
tok = tok->next();
}
return bool(noreturn==nullptr);
}
// variable is seen..
if (tok->varId() == var.declarationId()) {
// calling function that returns uninit data through pointer..
if (var.isPointer() &&
Token::Match(tok->next(), "= %name% (") &&
Token::simpleMatch(tok->linkAt(3), ") ;") &&
_settings->library.returnuninitdata.count(tok->strAt(2)) > 0U) {
*alloc = NO_CTOR_CALL;
continue;
}
if (var.isPointer() && (var.typeStartToken()->isStandardType() || (var.type() && var.type()->needInitialization == Type::True)) && Token::simpleMatch(tok->next(), "= new")) {
*alloc = CTOR_CALL;
if (var.typeScope() && var.typeScope()->numConstructors > 0)
return true;
continue;
}
if (!membervar.empty()) {
if (isMemberVariableAssignment(tok, membervar)) {
checkRhs(tok, var, *alloc, membervar);
return true;
}
if (isMemberVariableUsage(tok, var.isPointer(), *alloc, membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
return true;
} else {
// Use variable
if (!suppressErrors && isVariableUsage(tok, var.isPointer(), *alloc)) {
if (*alloc != NO_ALLOC)
uninitdataError(tok, tok->str());
else
uninitvarError(tok, tok->str());
}
else {
if (tok->strAt(1) == "=")
checkRhs(tok, var, *alloc, "");
// assume that variable is assigned
return true;
}
}
}
}
return false;
}
bool CheckUninitVar::checkIfForWhileHead(const Token *startparentheses, const Variable& var, bool suppressErrors, bool isuninit, Alloc alloc, const std::string &membervar)
{
const Token * const endpar = startparentheses->link();
if (Token::Match(startparentheses, "( ! %name% %oror%") && startparentheses->tokAt(2)->getValue(0))
suppressErrors = true;
for (const Token *tok = startparentheses->next(); tok && tok != endpar; tok = tok->next()) {
if (tok->varId() == var.declarationId()) {
if (Token::Match(tok, "%name% . %name%")) {
if (tok->strAt(2) == membervar) {
if (isMemberVariableAssignment(tok, membervar))
return true;
if (!suppressErrors && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
}
continue;
}
if (isVariableUsage(tok, var.isPointer(), alloc)) {
if (suppressErrors)
continue;
uninitvarError(tok, tok->str());
}
return true;
}
if (Token::Match(tok, "sizeof|decltype|offsetof ("))
tok = tok->next()->link();
if ((!isuninit || !membervar.empty()) && tok->str() == "&&")
suppressErrors = true;
}
return false;
}
bool CheckUninitVar::checkLoopBody(const Token *tok, const Variable& var, const Alloc alloc, const std::string &membervar, const bool suppressErrors)
{
const Token *usetok = nullptr;
assert(tok->str() == "{");
for (const Token * const end = tok->link(); tok != end; tok = tok->next()) {
if (tok->varId() == var.declarationId()) {
if (!membervar.empty()) {
if (isMemberVariableAssignment(tok, membervar)) {
bool assign = true;
bool rhs = false;
for (const Token *tok2 = tok->next(); tok2; tok2 = tok2->next()) {
if (tok2->str() == "=")
rhs = true;
if (tok2->str() == ";")
break;
if (rhs && tok2->varId() == var.declarationId() && isMemberVariableUsage(tok2, var.isPointer(), alloc, membervar)) {
assign = false;
break;
}
}
if (assign)
return true;
}
if (Token::Match(tok, "%name% ="))
return true;
if (isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
usetok = tok;
else if (Token::Match(tok->previous(), "[(,] %name% [,)]"))
return true;
} else {
if (isVariableUsage(tok, var.isPointer(), alloc))
usetok = tok;
else if (tok->strAt(1) == "=") {
// Is var used in rhs?
bool rhs = false;
std::stack<const Token *> tokens;
tokens.push(tok->next()->astOperand2());
while (!tokens.empty()) {
const Token *t = tokens.top();
tokens.pop();
if (!t)
continue;
if (t->varId() == var.declarationId()) {
// var is used in rhs
rhs = true;
break;
}
if (Token::simpleMatch(t->previous(),"sizeof ("))
continue;
tokens.push(t->astOperand1());
tokens.push(t->astOperand2());
}
if (!rhs)
return true;
} else {
return true;
}
}
}
if (Token::Match(tok, "sizeof|typeof ("))
tok = tok->next()->link();
if (Token::Match(tok, "asm ( %str% ) ;"))
return true;
}
if (!suppressErrors && usetok) {
if (membervar.empty())
uninitvarError(usetok, usetok->str());
else
uninitStructMemberError(usetok, usetok->str() + "." + membervar);
return true;
}
return false;
}
void CheckUninitVar::checkRhs(const Token *tok, const Variable &var, Alloc alloc, const std::string &membervar)
{
bool rhs = false;
unsigned int indent = 0;
while (nullptr != (tok = tok->next())) {
if (tok->str() == "=")
rhs = true;
else if (rhs && tok->varId() == var.declarationId()) {
if (membervar.empty() && isVariableUsage(tok, var.isPointer(), alloc))
uninitvarError(tok, tok->str());
else if (!membervar.empty() && isMemberVariableUsage(tok, var.isPointer(), alloc, membervar))
uninitStructMemberError(tok, tok->str() + "." + membervar);
} else if (tok->str() == ";" || (indent==0 && tok->str() == ","))
break;
else if (tok->str() == "(")
++indent;
else if (tok->str() == ")") {
if (indent == 0)
break;
--indent;
} else if (Token::simpleMatch(tok, "sizeof ("))
tok = tok->next()->link();
}
}
bool CheckUninitVar::isVariableUsage(const Token *vartok, bool pointer, Alloc alloc) const
{
if (alloc == NO_ALLOC && ((Token::Match(vartok->previous(), "return|delete") && vartok->strAt(1) != "=") || (vartok->strAt(-1) == "]" && vartok->linkAt(-1)->strAt(-1) == "delete")))
return true;
// Passing variable to typeof/__alignof__
if (Token::Match(vartok->tokAt(-3), "typeof|__alignof__ ( * %name%"))
return false;
// Accessing Rvalue member using "." or "->"
if (vartok->strAt(1) == "." && vartok->strAt(-1) != "&") {
// Is struct member passed to function?
if (!pointer && Token::Match(vartok->previous(), "[,(] %name% . %name%")) {
// TODO: there are FN currently:
// - should only return false if struct member is (or might be) array.
// - should only return false if function argument is (or might be) non-const pointer or reference
const Token *tok2 = vartok->next();
while (Token::Match(tok2,". %name%"))
tok2 = tok2->tokAt(2);
if (Token::Match(tok2, "[,)]"))
return false;
} else if (pointer && alloc != CTOR_CALL && Token::Match(vartok, "%name% . %name% (")) {
return true;
}
bool assignment = false;
const Token* parent = vartok->astParent();
while (parent) {
if (parent->str() == "=") {
assignment = true;
break;
}
if (alloc != NO_ALLOC && parent->str() == "(") {
if (_settings->library.functionpure.find(parent->strAt(-1)) == _settings->library.functionpure.end()) {
assignment = true;
break;
}
}
parent = parent->astParent();
}
if (!assignment)
return true;
}
// Passing variable to function..
if (Token::Match(vartok->previous(), "[(,] %name% [,)]") || Token::Match(vartok->tokAt(-2), "[(,] & %name% [,)]")) {
// locate start parentheses in function call..
unsigned int argumentNumber = 0;
const Token *start = vartok;
while (start && !Token::Match(start, "[;{}(]")) {
if (start->str() == ")")
start = start->link();
else if (start->str() == ",")
++argumentNumber;
start = start->previous();
}
// is this a function call?
if (start && Token::Match(start->previous(), "%name% (")) {
const bool address(vartok->previous()->str() == "&");
// check how function handle uninitialized data arguments..
const Function *func = start->previous()->function();
if (func) {
const Variable *arg = func->getArgumentVar(argumentNumber);
if (arg) {
const Token *argStart = arg->typeStartToken();
if (!address && Token::Match(argStart, "struct| %type% [,)]"))
return true;
if (!address && Token::Match(argStart, "struct| %type% %name% [,)]"))
return true;
if (pointer && !address && alloc == NO_ALLOC && Token::Match(argStart, "struct| %type% * %name% [,)]"))
return true;
while (argStart->previous() && argStart->previous()->isName())
argStart = argStart->previous();
if (Token::Match(argStart, "const %type% & %name% [,)]"))
return true;
if ((pointer || address) && alloc == NO_ALLOC && Token::Match(argStart, "const struct| %type% * %name% [,)]"))
return true;
if ((pointer || address) && Token::Match(argStart, "const %type% %name% [") && Token::Match(argStart->linkAt(3), "] [,)]"))
return true;
}
} else if (Token::Match(start->previous(), "if|while|for")) {
// control-flow statement reading the variable "by value"
return alloc == NO_ALLOC;
} else {
bool isnullbad = _settings->library.isnullargbad(start->previous(), argumentNumber + 1);
bool isuninitbad = _settings->library.isuninitargbad(start->previous(), argumentNumber + 1);
if (alloc != NO_ALLOC)
return isnullbad && isuninitbad;
return isuninitbad && (!address || isnullbad);
}
}
}
if (Token::Match(vartok->previous(), "++|--|%cop%")) {
if (_tokenizer->isCPP() && Token::Match(vartok->previous(), ">>|<<")) {
const Token* tok2 = vartok->previous();
if (Token::simpleMatch(tok2->astOperand1(), ">>"))
return false; // Looks like stream operator, initializes the variable
if (Token::simpleMatch(tok2, "<<")) {
// Looks like stream operator, but could also initialize the variable. Check lhs.
do {
tok2 = tok2->astOperand1();
} while (Token::simpleMatch(tok2, "<<"));
if (tok2->strAt(-1) == "::")
tok2 = tok2->previous();
if (tok2 && (Token::simpleMatch(tok2->previous(), "std ::") || (tok2->variable() && tok2->variable()->isStlType()) || tok2->isStandardType()))
return true;
}
const Variable *var = vartok->tokAt(-2)->variable();
return (var && var->typeStartToken()->isStandardType());
}
// is there something like: ; "*((&var ..expr.. =" => the variable is assigned
if (vartok->previous()->str() == "&" && !vartok->previous()->astOperand2())
return false;
// bailout to avoid fp for 'int x = 2 + x();' where 'x()' is a unseen preprocessor macro (seen in linux)
if (!pointer && vartok->next() && vartok->next()->str() == "(")
return false;
if (vartok->previous()->str() != "&" || !Token::Match(vartok->tokAt(-2), "[(,=?:]")) {
if (alloc != NO_ALLOC && vartok->previous()->str() == "*") {
const Token *parent = vartok->previous()->astParent();
if (parent && parent->str() == "=" && parent->astOperand1() == vartok->previous())
return false;
return true;
}
return alloc == NO_ALLOC;
}
}
if (alloc == NO_ALLOC && Token::Match(vartok->previous(), "= %name% ;|%cop%"))
return true;
if (Token::Match(vartok->previous(), "? %name%")) {
// this is only variable usage if variable is either:
// * unconditionally uninitialized
// * used in both rhs and lhs of ':' operator
bool rhs = false;
for (const Token *tok2 = vartok; tok2; tok2 = tok2->next()) {
if (tok2->str() == "(")
tok2 = tok2->link();
else if (tok2->str() == ":")
rhs = true;
else if (Token::Match(tok2, "[)];,{}=]"))
break;
else if (rhs && tok2->varId() == vartok->varId())
return true;
}
}
bool unknown = false;
if (pointer && CheckNullPointer::isPointerDeRef(vartok, unknown)) {
// pointer is allocated - dereferencing it is ok.
if (alloc != NO_ALLOC)
return false;
// function parameter?
bool functionParameter = false;
if (Token::Match(vartok->tokAt(-2), "%name% (") || vartok->previous()->str() == ",")
functionParameter = true;
// if this is not a function parameter report this dereference as variable usage
if (!functionParameter)
return true;
}
if (_tokenizer->isCPP() && Token::Match(vartok->next(), "<<|>>")) {
// Is this calculation done in rhs?
const Token *tok = vartok;
while (tok && Token::Match(tok, "%name%|.|::"))
tok = tok->previous();
if (Token::Match(tok, "[;{}]"))
return false;
// Is variable a known POD type then this is a variable usage,
// otherwise we assume it's not.
const Variable *var = vartok->variable();
return (var && var->typeStartToken()->isStandardType());
}
if (alloc == NO_ALLOC && vartok->next() && vartok->next()->isOp() && !vartok->next()->isAssignmentOp())
return true;
if (vartok->strAt(1) == "]")
return true;
return false;
}
bool CheckUninitVar::isMemberVariableAssignment(const Token *tok, const std::string &membervar)
{
if (Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar) {
if (Token::Match(tok->tokAt(3), "[=.[]"))
return true;
else if (Token::Match(tok->tokAt(-2), "[(,=] &"))
return true;
else if ((tok->previous() && tok->previous()->isConstOp()) || Token::Match(tok->previous(), "[|="))
; // member variable usage
else if (tok->tokAt(3)->isConstOp())
; // member variable usage
else
return true;
} else if (tok->strAt(1) == "=")
return true;
else if (tok->strAt(-1) == "&") {
if (Token::Match(tok->tokAt(-2), "[(,] & %name%")) {
// locate start parentheses in function call..
unsigned int argumentNumber = 0;
const Token *ftok = tok;
while (ftok && !Token::Match(ftok, "[;{}(]")) {
if (ftok->str() == ")")
ftok = ftok->link();
else if (ftok->str() == ",")
++argumentNumber;
ftok = ftok->previous();
}
// is this a function call?
ftok = ftok ? ftok->previous() : NULL;
if (Token::Match(ftok, "%name% (")) {
// check how function handle uninitialized data arguments..
const Function *function = ftok->function();
const Variable *arg = function ? function->getArgumentVar(argumentNumber) : NULL;
const Token *argStart = arg ? arg->typeStartToken() : NULL;
while (argStart && argStart->previous() && argStart->previous()->isName())
argStart = argStart->previous();
if (Token::Match(argStart, "const struct| %type% * const| %name% [,)]"))
return false;
}
else if (ftok && Token::simpleMatch(ftok->previous(), "= * ("))
return false;
}
return true;
}
return false;
}
bool CheckUninitVar::isMemberVariableUsage(const Token *tok, bool isPointer, Alloc alloc, const std::string &membervar) const
{
if (isMemberVariableAssignment(tok, membervar))
return false;
if (Token::Match(tok, "%name% . %name%") && tok->strAt(2) == membervar)
return true;
else if (!isPointer && Token::Match(tok->previous(), "[(,] %name% [,)]") && isVariableUsage(tok, isPointer, alloc))
return true;
else if (!isPointer && Token::Match(tok->previous(), "= %name% ;"))
return true;
// = *(&var);
else if (!isPointer &&
Token::simpleMatch(tok->astParent(),"&") &&
Token::simpleMatch(tok->astParent()->astParent(),"*") &&
Token::Match(tok->astParent()->astParent()->astParent(), "= * (| &") &&
tok->astParent()->astParent()->astParent()->astOperand2() == tok->astParent()->astParent())
return true;
else if (_settings->experimental &&
!isPointer &&
Token::Match(tok->tokAt(-2), "[(,] & %name% [,)]") &&
isVariableUsage(tok, isPointer, alloc))
return true;
return false;
}
void CheckUninitVar::uninitstringError(const Token *tok, const std::string &varname, bool strncpy_)
{
reportError(tok, Severity::error, "uninitstring", "Dangerous usage of '" + varname + "'" + (strncpy_ ? " (strncpy doesn't always null-terminate it)." : " (not null-terminated)."));
}
void CheckUninitVar::uninitdataError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "uninitdata", "Memory is allocated but not initialized: " + varname);
}
void CheckUninitVar::uninitvarError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "uninitvar", "Uninitialized variable: " + varname);
}
void CheckUninitVar::uninitStructMemberError(const Token *tok, const std::string &membername)
{
reportError(tok,
Severity::error,
"uninitStructMember",
"Uninitialized struct member: " + membername);
}
void CheckUninitVar::deadPointer()
{
const SymbolDatabase *symbolDatabase = _tokenizer->getSymbolDatabase();
std::list<Scope>::const_iterator scope;
// check every executable scope
for (scope = symbolDatabase->scopeList.begin(); scope != symbolDatabase->scopeList.end(); ++scope) {
if (!scope->isExecutable())
continue;
// Dead pointers..
for (const Token* tok = scope->classStart; tok != scope->classEnd; tok = tok->next()) {
if (tok->variable() &&
tok->variable()->isPointer() &&
isVariableUsage(tok, true, NO_ALLOC)) {
const Token *alias = tok->getValueTokenDeadPointer();
if (alias) {
deadPointerError(tok,alias);
}
}
}
}
}
void CheckUninitVar::deadPointerError(const Token *pointer, const Token *alias)
{
const std::string strpointer(pointer ? pointer->str() : std::string("pointer"));
const std::string stralias(alias ? alias->expressionString() : std::string("&x"));
reportError(pointer,
Severity::error,
"deadpointer",
"Dead pointer usage. Pointer '" + strpointer + "' is dead if it has been assigned '" + stralias + "' at line " + MathLib::toString(alias ? alias->linenr() : 0U) + ".");
}