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null pointers: better checking when dereferencing pointer and then checking if it is null (#485)

This commit is contained in:
Daniel Marjamäki 2009-07-21 17:00:11 +02:00
parent 6f646246ee
commit ba36c9426b
3 changed files with 15 additions and 63 deletions
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27
src/checkother.cpp
View File

@ -1028,11 +1028,7 @@ void CheckOther::nullPointer()
tok2 = tok2->next();
}
}
}
void CheckOther::invalidPointer()
{
// Dereferencing a pointer and then checking if it's NULL..
for (const Token *tok1 = _tokenizer->tokens(); tok1; tok1 = tok1->next())
{
@ -1041,16 +1037,11 @@ void CheckOther::invalidPointer()
if (std::string(tok1->strAt(1)) == tok1->strAt(3))
continue;
const unsigned int varid1(tok1->next()->varId());
tok1 = tok1->tokAt(3);
const unsigned int varid2(tok1->varId());
if (varid1 == 0 || varid2 == 0)
const unsigned int varid1(tok1->varId());
if (varid1 == 0)
continue;
// token where the variable is dereferenced..
const Token * dereferenced = 0;
unsigned int indentlevel2 = 0;
for (const Token *tok2 = tok1->tokAt(3); tok2; tok2 = tok2->next())
{
@ -1064,9 +1055,6 @@ void CheckOther::invalidPointer()
--indentlevel2;
}
else if (Token::Match(tok2, "* %varid%", varid1))
dereferenced = tok2;
// Reassignment of the struct
else if (tok2->varId() == varid1)
{
@ -1080,10 +1068,10 @@ void CheckOther::invalidPointer()
else if (indentlevel2 == 0 && tok2->str() == "return")
break;
else if (dereferenced && tok2->str() == "if")
else if (Token::Match(tok2, "if ( !| %varid% )", varid1))
{
if (Token::Match(tok2, "if ( !| %varid% )", varid2))
invalidPointerError(dereferenced);
nullPointerError(tok1);
break;
}
}
}
@ -1189,11 +1177,6 @@ void CheckOther::nullPointerError(const Token *tok)
reportError(tok, Severity::error, "nullPointer", "Possible null pointer dereference");
}
void CheckOther::invalidPointerError(const Token *tok)
{
reportError(tok, Severity::error, "invalidPointer", "Possible invalid pointer dereference");
}
void CheckOther::zerodivError(const Token *tok)
{
reportError(tok, Severity::error, "zerodiv", "Division by zero");

7
src/checkother.h
View File

@ -72,7 +72,6 @@ public:
checkOther.strPlusChar();
checkOther.invalidFunctionUsage();
checkOther.nullPointer();
checkOther.invalidPointer();
checkOther.checkZeroDivision();
}
@ -112,9 +111,6 @@ public:
/** possible null pointer dereference */
void nullPointer();
/** possible invalid pointer dereference */
void invalidPointer();
/** Check zero division*/
void checkZeroDivision();
@ -145,7 +141,6 @@ private:
void conditionAlwaysTrueFalse(const Token *tok, const std::string &truefalse);
void strPlusChar(const Token *tok);
void nullPointerError(const Token *tok);
void invalidPointerError(const Token *tok);
void zerodivError(const Token *tok);
void getErrorMessages()
@ -168,7 +163,6 @@ private:
conditionAlwaysTrueFalse(0, "true/false");
strPlusChar(0);
nullPointerError(0);
invalidPointerError(0);
zerodivError(0);
}
@ -192,7 +186,6 @@ private:
" * condition that is always true/false\n"
" * unusal pointer arithmetic. For example: \"abc\" + 'd'\n"
" * dereferencing a null pointer\n"
" * dereferencing an invalid pointer\n"
" * [[IncompleteStatement|Incomplete statement]]\n";
}
};

44
test/testother.cpp
View File

@ -58,8 +58,7 @@ private:
TEST_CASE(nullpointer1);
TEST_CASE(nullpointer2);
TEST_CASE(invalidpointer);
TEST_CASE(nullpointer3); // dereferencing struct and then checking if it's null
TEST_CASE(oldStylePointerCast);
}
@ -446,40 +445,20 @@ private:
ASSERT_EQUALS("", errout.str());
}
void checkInvalidPointer(const char code[])
{
// Tokenize..
Tokenizer tokenizer;
std::istringstream istr(code);
tokenizer.tokenize(istr, "test.cpp");
tokenizer.setVarId();
// Clear the error buffer..
errout.str("");
// Check for redundant code..
Settings settings;
settings._checkCodingStyle = true;
CheckOther checkOther(&tokenizer, &settings, this);
checkOther.invalidPointer();
}
void invalidpointer()
// Dereferencing a struct and then checking if it is null
void nullpointer3()
{
// errors..
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" int *a = abc->a;\n"
" *a;\n"
" if (!abc)\n"
" ;\n"
"}\n");
ASSERT_EQUALS("[test.cpp:4]: (error) Possible invalid pointer dereference\n", errout.str());
ASSERT_EQUALS("[test.cpp:3]: (error) Possible null pointer dereference\n", errout.str());
// ok dereferencing in a condition
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" if (abc && abc->a);\n"
" if (!abc)\n"
@ -488,7 +467,7 @@ private:
ASSERT_EQUALS("", errout.str());
// ok to use a linked list..
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" abc = abc->next;\n"
" if (!abc)\n"
@ -497,20 +476,18 @@ private:
ASSERT_EQUALS("", errout.str());
// reassign struct..
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" a = abc->a;\n"
" *a;\n"
" abc = abc->next;\n"
" if (!abc)\n"
" ;\n"
"}\n");
ASSERT_EQUALS("", errout.str());
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" a = abc->a;\n"
" *a;\n"
" f(&abc);\n"
" if (!abc)\n"
" ;\n"
@ -518,12 +495,11 @@ private:
ASSERT_EQUALS("", errout.str());
// goto..
checkInvalidPointer("void foo(struct ABC *abc)\n"
checkNullPointer("void foo(struct ABC *abc)\n"
"{\n"
" if (!abc)\n"
" goto out;"
" a = abc->a;\n"
" *a;\n"
" return;\n"
"out:\n"
" if (!abc)\n"