cppcheck/lib/checkuninitvar.cpp

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/*
* Cppcheck - A tool for static C/C++ code analysis
* Copyright (C) 2007-2011 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 <algorithm>
//---------------------------------------------------------------------------
// Register this check class (by creating a static instance of it)
namespace
{
CheckUninitVar instance;
}
//---------------------------------------------------------------------------
/// @addtogroup Checks
/// @{
/**
* @brief %Check that uninitialized variables aren't used (using ExecutionPath)
* */
class UninitVar : public ExecutionPath
{
public:
/** Startup constructor */
UninitVar(Check *c)
: ExecutionPath(c, 0), pointer(false), array(false), alloc(false), strncpy_(false), memset_nonzero(false)
{
}
private:
/** Create a copy of this check */
ExecutionPath *copy()
{
return new UninitVar(*this);
}
/** no implementation => compiler error if used */
void operator=(const UninitVar &);
/** internal constructor for creating extra checks */
UninitVar(Check *c, unsigned int v, const std::string &name, bool p, bool a)
: ExecutionPath(c, v), varname(name), pointer(p), array(a), 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 (varname == c->varname && pointer == c->pointer && array == c->array && alloc == c->alloc && strncpy_ == c->strncpy_ && memset_nonzero == c->memset_nonzero);
}
/** variable name for this check */
const std::string varname;
/** is this variable a pointer? */
const bool pointer;
/** is this variable an array? */
const bool array;
/** 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)
c->alloc = true;
}
}
/** 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->array)
{
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->pointer && !c->alloc)
{
CheckUninitVar *checkUninitVar = dynamic_cast<CheckUninitVar *>(c->owner);
if (checkUninitVar)
{
checkUninitVar->uninitvarError(tok, c->varname);
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->pointer)
{
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->pointer || c->array))
{
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->array || (c->pointer && c->alloc)))
continue;
// mode 2 : bad usage of pointer. if it's not a pointer then the usage is ok.
// example: ptr->foo();
if (mode == 2 && !c->pointer)
continue;
// mode 3 : using dead pointer is invalid.
if (mode == 3 && (!c->pointer || c->alloc))
continue;
// mode 4 : reading uninitialized array or pointer is invalid.
if (mode == 4 && (!c->array && !c->pointer))
continue;
CheckUninitVar *checkUninitVar = dynamic_cast<CheckUninitVar *>(c->owner);
if (checkUninitVar)
{
if (c->strncpy_ || c->memset_nonzero)
checkUninitVar->uninitstringError(tok, c->varname, c->strncpy_);
else if (c->pointer && c->alloc)
checkUninitVar->uninitdataError(tok, c->varname);
else
checkUninitVar->uninitvarError(tok, c->varname);
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);
}
/**
* 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, 2);
}
/**
* 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, 3);
}
/**
* 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, 4);
}
/** declaring a variable */
void declare(std::list<ExecutionPath *> &checks, const Token *vartok, const Token &tok, const bool p, const bool a) const
{
if (vartok->varId() == 0)
return;
// Suppress warnings if variable in inner scope has same name as variable in outer scope
if (!tok.isStandardType())
{
std::set<unsigned int> dup;
for (std::list<ExecutionPath *>::const_iterator it = checks.begin(); it != checks.end(); ++it)
{
UninitVar *c = dynamic_cast<UninitVar *>(*it);
if (c && c->varname == vartok->str() && c->varId != vartok->varId())
dup.insert(c->varId);
}
if (!dup.empty())
{
for (std::set<unsigned int>::const_iterator it = dup.begin(); it != dup.end(); ++it)
bailOutVar(checks, *it);
return;
}
}
if (a || p || tok.isStandardType())
checks.push_back(new UninitVar(owner, vartok->varId(), vartok->str(), p, a));
}
/**
* Parse right hand side expression in statement
* @param tok2 start token of rhs
* @param checks the execution paths
*/
void parserhs(const Token *tok2, std::list<ExecutionPath *> &checks) const
{
// check variable usages in rhs/index
while (NULL != (tok2 = tok2->next()))
{
if (Token::Match(tok2, "[;)=?]"))
break;
if (Token::Match(tok2, "%var% ("))
break;
if (tok2->varId() &&
!Token::Match(tok2->previous(), "&|::") &&
!Token::simpleMatch(tok2->tokAt(-2), "& (") &&
!Token::simpleMatch(tok2->next(), "="))
{
// Multiple assignments..
if (Token::Match(tok2->next(), ".|["))
{
const Token * tok3 = tok2;
while (tok3)
{
if (Token::Match(tok3->next(), ". %var%"))
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.previous(), "[;{}] %var%") && tok.str() != "return")
{
if (Token::Match(&tok, "enum %type% {"))
return tok.tokAt(2)->link();
const Token * vartok = &tok;
while (Token::Match(vartok, "const|struct"))
vartok = vartok->next();
if (Token::Match(vartok, "%type% *| %var% ;"))
{
vartok = vartok->next();
const bool p(vartok->str() == "*");
if (p)
vartok = vartok->next();
declare(checks, vartok, tok, p, false);
return vartok;
}
// Variable declaration for array..
if (Token::Match(vartok, "%type% %var% [") &&
vartok->isStandardType() &&
Token::simpleMatch(vartok->tokAt(2)->link(), "] ;"))
{
vartok = vartok->next();
declare(checks, vartok, tok, false, true);
return vartok->next()->link();
}
// Template pointer variable..
if (Token::Match(vartok, "%type% ::|<"))
{
while (Token::Match(vartok, "%type% ::"))
vartok = vartok->tokAt(2);
if (Token::Match(vartok, "%type% < %type%"))
{
vartok = vartok->tokAt(3);
while (vartok && (vartok->str() == "*" || vartok->isName()))
vartok = vartok->next();
if (Token::Match(vartok, "> * %var% ;"))
{
declare(checks, vartok->tokAt(2), tok, true, false);
return vartok->tokAt(2);
}
}
}
}
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() == "=" || tok2->str() == ">>" || tok2->str() == "?")
{
assignment = true;
break;
}
}
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% [+-,)]"))
{
use(checks, &tok);
//use_array(checks, &tok);
return &tok;
}
// Used..
2011-04-10 11:28:18 +02:00
if (Token::Match(tok.previous(), "[[(,+-*/|=] %var% ]|)|,|;|%op%"))
{
// initialize reference variable
if (Token::Match(tok.tokAt(-3), "& %var% ="))
bailOutVar(checks, tok.varId());
else
use(checks, &tok);
return &tok;
}
if (Token::Match(tok.previous(), "++|--") || Token::Match(tok.next(), "++|--"))
{
use(checks, &tok);
return &tok;
}
if (Token::Match(tok.previous(), "[;{}] %var% [=[.]"))
{
if (tok.next()->str() == ".")
{
if (use_dead_pointer(checks, &tok))
{
return &tok;
}
}
else
{
const Token *tok2 = tok.next();
if (tok2->str() == "[" && Token::simpleMatch(tok2->link(), "] ="))
{
if (use_dead_pointer(checks, &tok))
{
return &tok;
}
parserhs(tok2, checks);
tok2 = tok2->link()->next();
}
parserhs(tok2, checks);
}
// pointer aliasing?
if (Token::Match(tok.tokAt(2), "%var% ;"))
{
pointer_assignment(checks, &tok, tok.tokAt(2));
}
}
if (Token::simpleMatch(tok.next(), "("))
{
use_pointer(checks, &tok);
}
if (Token::Match(tok.tokAt(-2), "[;{}] *"))
{
if (Token::simpleMatch(tok.next(), "="))
{
// 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 ["))
{
alloc_pointer(checks, tok.varId());
if (tok.tokAt(3)->str() == "(")
return tok.tokAt(3);
}
else if (Token::Match(tok.previous(), "<<|>>") || Token::simpleMatch(tok.next(), "="))
{
// TODO: Don't bail out for "<<" and ">>" if these are
// just computations
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
if (Token::simpleMatch(tok.next(), "["))
{
const Token *tok2 = tok.next()->link();
if (Token::simpleMatch(tok2 ? tok2->next() : 0, "="))
{
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
}
if (Token::simpleMatch(tok.previous(), "delete") ||
Token::simpleMatch(tok.tokAt(-3), "delete [ ]"))
{
dealloc_pointer(checks, &tok);
return &tok;
}
}
if (Token::Match(&tok, "%var% (") && uvarFunctions.find(tok.str()) == uvarFunctions.end())
{
// 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% )"))
{
dealloc_pointer(checks, tok.tokAt(2));
return tok.tokAt(3);
}
// parse usage..
{
std::list<const Token *> var;
CheckNullPointer::parseFunctionCall(tok, var, 1);
for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
2011-02-26 20:08:37 +01:00
{
use_array(checks, *it);
2011-02-26 20:08:37 +01:00
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, 0);
for (std::list<const Token *>::const_iterator it = var2.begin(); it != var2.end(); ++it)
{
if (std::find(var.begin(), var.end(), *it) == var.end())
use_dead_pointer(checks, *it);
}
}
// strncpy doesn't 0-terminate first parameter
if (Token::Match(&tok, "strncpy ( %var% ,"))
{
if (Token::Match(tok.tokAt(4), "%str% ,"))
{
if (Token::Match(tok.tokAt(6), "%num% )"))
{
2010-12-31 09:51:27 +01:00
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 ( %var% , !!0 , %num% )"))
{
init_memset_nonzero(checks, tok.tokAt(2));
return tok.next()->link();
}
if (Token::simpleMatch(&tok, "asm ( )"))
{
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% (") && CheckNullPointer::isUpper(tok2->str()))
{
tok2 = tok2->next()->link();
if (!tok2)
break;
}
else if (tok2->varId())
{
if (Token::Match(tok2->tokAt(-2), "[(,] *") || Token::Match(tok2->next(), ". %var%"))
{
// find function call..
const Token *functionCall = tok2;
while (0 != (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() && !CheckNullPointer::isUpper(functionCall->str()) && 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->array || (c->pointer && 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, "( * %var% ) ("))
{
// is the variable passed as a parameter to some function?
unsigned int parlevel = 0;
for (const Token *tok2 = tok.link()->next(); tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")")
{
if (parlevel <= 1)
break;
--parlevel;
}
else 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(), "%var% ;"))
{
use(checks, tok.next());
}
else if (Token::Match(tok.next(), "%var% ["))
{
use_array_or_pointer_data(checks, tok.next());
}
}
if (tok.varId())
{
if (Token::simpleMatch(tok.previous(), "="))
{
if (Token::Match(tok.tokAt(-3), "& %var% ="))
{
bailOutVar(checks, tok.varId());
return &tok;
}
if (!Token::Match(tok.tokAt(-3), ". %var% ="))
{
if (!Token::Match(tok.tokAt(-3), "[;{}] %var% ="))
{
use(checks, &tok);
return &tok;
}
const unsigned int varid2 = tok.tokAt(-2)->varId();
if (varid2)
{
{
use(checks, &tok);
return &tok;
}
}
}
}
if (Token::simpleMatch(tok.next(), "."))
{
bailOutVar(checks, tok.varId());
return &tok;
}
if (Token::simpleMatch(tok.next(), "["))
{
ExecutionPath::bailOutVar(checks, tok.varId());
return &tok;
}
if (Token::Match(tok.tokAt(-2), "[,(=] *"))
{
use_pointer(checks, &tok);
return &tok;
}
if (Token::simpleMatch(tok.previous(), "&"))
{
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())
{
unsigned int indentlevel = 0;
for (const Token *tok3 = tok2->tokAt(5); tok3; tok3 = tok3->next())
{
if (tok3->str() == "{")
++indentlevel;
else if (tok3->str() == "}")
{
if (indentlevel == 0)
break;
--indentlevel;
}
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, "%var% <|<=|==|!=|)"))
use(checks, &tok);
else if (Token::Match(&tok, "!| %var% ["))
use_array_or_pointer_data(checks, tok.str() == "!" ? tok.next() : &tok);
else if (Token::Match(&tok, "!| %var% ("))
{
std::list<const Token *> var;
CheckNullPointer::parseFunctionCall(tok.str() == "!" ? *tok.next() : tok, var, 1);
for (std::list<const Token *>::const_iterator it = var.begin(); it != var.end(); ++it)
use_array(checks, *it);
}
else if (Token::Match(&tok, "! %var% )"))
{
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
unsigned int parlevel = 0;
for (const Token *tok2 = tok->tokAt(2); tok2; tok2 = tok2->next())
{
if (tok2->str() == "(")
++parlevel;
else if (tok2->str() == ")")
{
if (parlevel == 0)
break;
--parlevel;
}
else if (tok2->varId())
ExecutionPath::bailOutVar(checks, tok2->varId());
}
}
const Token *next = parse(*tok, checks);
tok = next->next();
}
}
public:
/** Functions that don't handle uninitialized variables well */
static std::set<std::string> uvarFunctions;
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(), "%var% ( %type%"))
{
if (!Token::Match(tok->tokAt(2)->link(), ") [{;]"))
continue;
const Token *tok2 = tok->tokAt(3);
while (tok2 && tok2->str() != ")")
{
if (tok2->str() == ",")
tok2 = tok2->next();
if (Token::Match(tok2, "%type% %var% ,|)") && tok2->isStandardType())
{
tok2 = tok2->tokAt(2);
continue;
}
if (tok2->isStandardType() && Token::Match(tok2, "%type% & %var% ,|)"))
{
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 (Token::Match(tok3->previous(), "++|--") ||
Token::Match(tok3->next(), "++|--"))
{
r = true;
}
else
{
w = true;
break;
}
}
}
if (!r || w)
break;
tok2 = tok2->tokAt(3);
continue;
}
if (Token::Match(tok2, "const %type% &|*| const| %var% ,|)") && tok2->next()->isStandardType())
{
tok2 = tok2->tokAt(3);
while (tok2->isName())
tok2 = tok2->next();
continue;
}
if (Token::Match(tok2, "const %type% %var% [ ] ,|)") && 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% * %var% ,|)"))
{
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());
}
}
}
};
/** Functions that don't handle uninitialized variables well */
std::set<std::string> UninitVar::uvarFunctions;
/// @}
void CheckUninitVar::analyse(const Token * const tokens, std::set<std::string> &func) const
{
UninitVar::analyseFunctions(tokens, func);
}
void CheckUninitVar::saveAnalysisData(const std::set<std::string> &data) const
{
UninitVar::uvarFunctions.insert(data.begin(), data.end());
}
void CheckUninitVar::executionPaths()
{
// check if variable is accessed uninitialized..
{
// no writing if multiple threads are used (TODO: thread safe analysis?)
if (_settings->_jobs == 1)
UninitVar::analyseFunctions(_tokenizer->tokens(), UninitVar::uvarFunctions);
UninitVar c(this);
checkExecutionPaths(_tokenizer->tokens(), &c);
}
}
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 0-terminate it)" : " (not 0-terminated)"));
}
void CheckUninitVar::uninitdataError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "uninitdata", "Data is allocated but not initialized: " + varname);
}
void CheckUninitVar::uninitvarError(const Token *tok, const std::string &varname)
{
reportError(tok, Severity::error, "uninitvar", "Uninitialized variable: " + varname);
}