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//===-- StreamChecker.cpp -----------------------------------------*- C++ -*--//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file defines checkers that model and check stream handling functions.
//
//===----------------------------------------------------------------------===//
#include "GRExprEngineExperimentalChecks.h"
#include "clang/Checker/BugReporter/BugType.h"
#include "clang/Checker/PathSensitive/CheckerVisitor.h"
#include "clang/Checker/PathSensitive/GRState.h"
#include "clang/Checker/PathSensitive/GRStateTrait.h"
#include "clang/Checker/PathSensitive/SymbolManager.h"
#include "llvm/ADT/ImmutableMap.h"
using namespace clang;
namespace {
class StreamChecker : public CheckerVisitor<StreamChecker> {
IdentifierInfo *II_fopen, *II_fread, *II_fseek, *II_ftell, *II_rewind;
BuiltinBug *BT_nullfp;
public:
StreamChecker()
: II_fopen(0), II_fread(0), II_fseek(0), II_ftell(0), II_rewind(0),
BT_nullfp(0) {}
static void *getTag() {
static int x;
return &x;
}
virtual bool EvalCallExpr(CheckerContext &C, const CallExpr *CE);
private:
void FOpen(CheckerContext &C, const CallExpr *CE);
void FRead(CheckerContext &C, const CallExpr *CE);
void FSeek(CheckerContext &C, const CallExpr *CE);
void FTell(CheckerContext &C, const CallExpr *CE);
void Rewind(CheckerContext &C, const CallExpr *CE);
bool CheckNullStream(SVal SV, const GRState *state, CheckerContext &C);
};
} // end anonymous namespace
void clang::RegisterStreamChecker(GRExprEngine &Eng) {
Eng.registerCheck(new StreamChecker());
}
bool StreamChecker::EvalCallExpr(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
const Expr *Callee = CE->getCallee();
SVal L = state->getSVal(Callee);
const FunctionDecl *FD = L.getAsFunctionDecl();
if (!FD)
return false;
ASTContext &Ctx = C.getASTContext();
if (!II_fopen)
II_fopen = &Ctx.Idents.get("fopen");
if (!II_fread)
II_fread = &Ctx.Idents.get("fread");
if (!II_fseek)
II_fseek = &Ctx.Idents.get("fseek");
if (!II_ftell)
II_ftell = &Ctx.Idents.get("ftell");
if (!II_rewind)
II_rewind = &Ctx.Idents.get("rewind");
if (FD->getIdentifier() == II_fopen) {
FOpen(C, CE);
return true;
}
if (FD->getIdentifier() == II_fread) {
FRead(C, CE);
return true;
}
if (FD->getIdentifier() == II_fseek) {
FSeek(C, CE);
return true;
}
if (FD->getIdentifier() == II_ftell) {
FTell(C, CE);
return true;
}
if (FD->getIdentifier() == II_rewind) {
Rewind(C, CE);
return true;
}
return false;
}
void StreamChecker::FOpen(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
unsigned Count = C.getNodeBuilder().getCurrentBlockCount();
ValueManager &ValMgr = C.getValueManager();
DefinedSVal RetVal = cast<DefinedSVal>(ValMgr.getConjuredSymbolVal(0, CE,
Count));
state = state->BindExpr(CE, RetVal);
ConstraintManager &CM = C.getConstraintManager();
// Bifurcate the state into two: one with a valid FILE* pointer, the other
// with a NULL.
const GRState *stateNotNull, *stateNull;
llvm::tie(stateNotNull, stateNull) = CM.AssumeDual(state, RetVal);
C.addTransition(stateNotNull);
C.addTransition(stateNull);
}
void StreamChecker::FRead(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
if (CheckNullStream(state->getSVal(CE->getArg(3)), state, C))
return;
}
void StreamChecker::FSeek(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
if (CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::FTell(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
if (CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) {
const GRState *state = C.getState();
if (CheckNullStream(state->getSVal(CE->getArg(0)), state, C))
return;
}
bool StreamChecker::CheckNullStream(SVal SV, const GRState *state,
CheckerContext &C) {
const DefinedSVal *DV = dyn_cast<DefinedSVal>(&SV);
if (!DV)
return false;
ConstraintManager &CM = C.getConstraintManager();
const GRState *stateNotNull, *stateNull;
llvm::tie(stateNotNull, stateNull) = CM.AssumeDual(state, *DV);
if (!stateNotNull && stateNull) {
if (ExplodedNode *N = C.GenerateSink(stateNull)) {
if (!BT_nullfp)
BT_nullfp = new BuiltinBug("NULL stream pointer",
"Stream pointer might be NULL.");
BugReport *R =new BugReport(*BT_nullfp, BT_nullfp->getDescription(), N);
C.EmitReport(R);
}
return true;
}
return false;
}
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