422 lines
14 KiB
C++
422 lines
14 KiB
C++
//===-- StreamChecker.cpp -----------------------------------------*- C++ -*--//
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//
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// The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines checkers that model and check stream handling functions.
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//
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//===----------------------------------------------------------------------===//
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#include "ClangSACheckers.h"
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#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
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#include "clang/StaticAnalyzer/Core/Checker.h"
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#include "clang/StaticAnalyzer/Core/CheckerManager.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/ProgramStateTrait.h"
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#include "clang/StaticAnalyzer/Core/PathSensitive/SymbolManager.h"
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#include "llvm/ADT/ImmutableMap.h"
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using namespace clang;
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using namespace ento;
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namespace {
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struct StreamState {
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enum Kind { Opened, Closed, OpenFailed, Escaped } K;
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const Stmt *S;
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StreamState(Kind k, const Stmt *s) : K(k), S(s) {}
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bool isOpened() const { return K == Opened; }
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bool isClosed() const { return K == Closed; }
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//bool isOpenFailed() const { return K == OpenFailed; }
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//bool isEscaped() const { return K == Escaped; }
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bool operator==(const StreamState &X) const {
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return K == X.K && S == X.S;
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}
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static StreamState getOpened(const Stmt *s) { return StreamState(Opened, s); }
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static StreamState getClosed(const Stmt *s) { return StreamState(Closed, s); }
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static StreamState getOpenFailed(const Stmt *s) {
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return StreamState(OpenFailed, s);
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}
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static StreamState getEscaped(const Stmt *s) {
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return StreamState(Escaped, s);
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}
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void Profile(llvm::FoldingSetNodeID &ID) const {
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ID.AddInteger(K);
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ID.AddPointer(S);
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}
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};
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class StreamChecker : public Checker<eval::Call,
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check::DeadSymbols > {
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mutable IdentifierInfo *II_fopen, *II_tmpfile, *II_fclose, *II_fread,
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*II_fwrite,
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*II_fseek, *II_ftell, *II_rewind, *II_fgetpos, *II_fsetpos,
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*II_clearerr, *II_feof, *II_ferror, *II_fileno;
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mutable OwningPtr<BuiltinBug> BT_nullfp, BT_illegalwhence,
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BT_doubleclose, BT_ResourceLeak;
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public:
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StreamChecker()
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: II_fopen(0), II_tmpfile(0) ,II_fclose(0), II_fread(0), II_fwrite(0),
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II_fseek(0), II_ftell(0), II_rewind(0), II_fgetpos(0), II_fsetpos(0),
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II_clearerr(0), II_feof(0), II_ferror(0), II_fileno(0) {}
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bool evalCall(const CallExpr *CE, CheckerContext &C) const;
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void checkDeadSymbols(SymbolReaper &SymReaper, CheckerContext &C) const;
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private:
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void Fopen(CheckerContext &C, const CallExpr *CE) const;
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void Tmpfile(CheckerContext &C, const CallExpr *CE) const;
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void Fclose(CheckerContext &C, const CallExpr *CE) const;
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void Fread(CheckerContext &C, const CallExpr *CE) const;
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void Fwrite(CheckerContext &C, const CallExpr *CE) const;
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void Fseek(CheckerContext &C, const CallExpr *CE) const;
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void Ftell(CheckerContext &C, const CallExpr *CE) const;
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void Rewind(CheckerContext &C, const CallExpr *CE) const;
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void Fgetpos(CheckerContext &C, const CallExpr *CE) const;
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void Fsetpos(CheckerContext &C, const CallExpr *CE) const;
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void Clearerr(CheckerContext &C, const CallExpr *CE) const;
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void Feof(CheckerContext &C, const CallExpr *CE) const;
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void Ferror(CheckerContext &C, const CallExpr *CE) const;
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void Fileno(CheckerContext &C, const CallExpr *CE) const;
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void OpenFileAux(CheckerContext &C, const CallExpr *CE) const;
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ProgramStateRef CheckNullStream(SVal SV, ProgramStateRef state,
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CheckerContext &C) const;
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ProgramStateRef CheckDoubleClose(const CallExpr *CE, ProgramStateRef state,
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CheckerContext &C) const;
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};
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} // end anonymous namespace
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REGISTER_MAP_WITH_PROGRAMSTATE(StreamMap, SymbolRef, StreamState)
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bool StreamChecker::evalCall(const CallExpr *CE, CheckerContext &C) const {
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const FunctionDecl *FD = C.getCalleeDecl(CE);
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if (!FD || FD->getKind() != Decl::Function)
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return false;
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ASTContext &Ctx = C.getASTContext();
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if (!II_fopen)
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II_fopen = &Ctx.Idents.get("fopen");
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if (!II_tmpfile)
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II_tmpfile = &Ctx.Idents.get("tmpfile");
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if (!II_fclose)
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II_fclose = &Ctx.Idents.get("fclose");
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if (!II_fread)
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II_fread = &Ctx.Idents.get("fread");
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if (!II_fwrite)
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II_fwrite = &Ctx.Idents.get("fwrite");
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if (!II_fseek)
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II_fseek = &Ctx.Idents.get("fseek");
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if (!II_ftell)
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II_ftell = &Ctx.Idents.get("ftell");
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if (!II_rewind)
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II_rewind = &Ctx.Idents.get("rewind");
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if (!II_fgetpos)
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II_fgetpos = &Ctx.Idents.get("fgetpos");
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if (!II_fsetpos)
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II_fsetpos = &Ctx.Idents.get("fsetpos");
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if (!II_clearerr)
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II_clearerr = &Ctx.Idents.get("clearerr");
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if (!II_feof)
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II_feof = &Ctx.Idents.get("feof");
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if (!II_ferror)
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II_ferror = &Ctx.Idents.get("ferror");
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if (!II_fileno)
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II_fileno = &Ctx.Idents.get("fileno");
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if (FD->getIdentifier() == II_fopen) {
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Fopen(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_tmpfile) {
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Tmpfile(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fclose) {
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Fclose(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fread) {
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Fread(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fwrite) {
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Fwrite(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fseek) {
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Fseek(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_ftell) {
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Ftell(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_rewind) {
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Rewind(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fgetpos) {
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Fgetpos(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fsetpos) {
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Fsetpos(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_clearerr) {
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Clearerr(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_feof) {
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Feof(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_ferror) {
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Ferror(C, CE);
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return true;
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}
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if (FD->getIdentifier() == II_fileno) {
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Fileno(C, CE);
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return true;
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}
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return false;
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}
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void StreamChecker::Fopen(CheckerContext &C, const CallExpr *CE) const {
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OpenFileAux(C, CE);
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}
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void StreamChecker::Tmpfile(CheckerContext &C, const CallExpr *CE) const {
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OpenFileAux(C, CE);
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}
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void StreamChecker::OpenFileAux(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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SValBuilder &svalBuilder = C.getSValBuilder();
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const LocationContext *LCtx = C.getPredecessor()->getLocationContext();
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DefinedSVal RetVal = svalBuilder.conjureSymbolVal(0, CE, LCtx, C.blockCount())
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.castAs<DefinedSVal>();
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state = state->BindExpr(CE, C.getLocationContext(), RetVal);
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ConstraintManager &CM = C.getConstraintManager();
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// Bifurcate the state into two: one with a valid FILE* pointer, the other
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// with a NULL.
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ProgramStateRef stateNotNull, stateNull;
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llvm::tie(stateNotNull, stateNull) = CM.assumeDual(state, RetVal);
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if (SymbolRef Sym = RetVal.getAsSymbol()) {
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// if RetVal is not NULL, set the symbol's state to Opened.
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stateNotNull =
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stateNotNull->set<StreamMap>(Sym,StreamState::getOpened(CE));
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stateNull =
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stateNull->set<StreamMap>(Sym, StreamState::getOpenFailed(CE));
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C.addTransition(stateNotNull);
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C.addTransition(stateNull);
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}
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}
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void StreamChecker::Fclose(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = CheckDoubleClose(CE, C.getState(), C);
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if (state)
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C.addTransition(state);
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}
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void StreamChecker::Fread(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(3), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Fwrite(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(3), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Fseek(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!(state = CheckNullStream(state->getSVal(CE->getArg(0),
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C.getLocationContext()), state, C)))
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return;
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// Check the legality of the 'whence' argument of 'fseek'.
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SVal Whence = state->getSVal(CE->getArg(2), C.getLocationContext());
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Optional<nonloc::ConcreteInt> CI = Whence.getAs<nonloc::ConcreteInt>();
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if (!CI)
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return;
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int64_t x = CI->getValue().getSExtValue();
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if (x >= 0 && x <= 2)
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return;
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if (ExplodedNode *N = C.addTransition(state)) {
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if (!BT_illegalwhence)
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BT_illegalwhence.reset(new BuiltinBug("Illegal whence argument",
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"The whence argument to fseek() should be "
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"SEEK_SET, SEEK_END, or SEEK_CUR."));
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BugReport *R = new BugReport(*BT_illegalwhence,
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BT_illegalwhence->getDescription(), N);
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C.emitReport(R);
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}
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}
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void StreamChecker::Ftell(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Rewind(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Fgetpos(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Fsetpos(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Clearerr(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Feof(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Ferror(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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void StreamChecker::Fileno(CheckerContext &C, const CallExpr *CE) const {
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ProgramStateRef state = C.getState();
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if (!CheckNullStream(state->getSVal(CE->getArg(0), C.getLocationContext()),
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state, C))
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return;
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}
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ProgramStateRef StreamChecker::CheckNullStream(SVal SV, ProgramStateRef state,
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CheckerContext &C) const {
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Optional<DefinedSVal> DV = SV.getAs<DefinedSVal>();
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if (!DV)
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return 0;
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ConstraintManager &CM = C.getConstraintManager();
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ProgramStateRef stateNotNull, stateNull;
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llvm::tie(stateNotNull, stateNull) = CM.assumeDual(state, *DV);
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if (!stateNotNull && stateNull) {
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if (ExplodedNode *N = C.generateSink(stateNull)) {
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if (!BT_nullfp)
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BT_nullfp.reset(new BuiltinBug("NULL stream pointer",
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"Stream pointer might be NULL."));
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BugReport *R =new BugReport(*BT_nullfp, BT_nullfp->getDescription(), N);
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C.emitReport(R);
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}
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return 0;
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}
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return stateNotNull;
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}
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ProgramStateRef StreamChecker::CheckDoubleClose(const CallExpr *CE,
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ProgramStateRef state,
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CheckerContext &C) const {
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SymbolRef Sym =
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state->getSVal(CE->getArg(0), C.getLocationContext()).getAsSymbol();
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if (!Sym)
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return state;
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const StreamState *SS = state->get<StreamMap>(Sym);
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// If the file stream is not tracked, return.
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if (!SS)
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return state;
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// Check: Double close a File Descriptor could cause undefined behaviour.
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// Conforming to man-pages
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if (SS->isClosed()) {
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ExplodedNode *N = C.generateSink();
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if (N) {
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if (!BT_doubleclose)
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BT_doubleclose.reset(new BuiltinBug("Double fclose",
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"Try to close a file Descriptor already"
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" closed. Cause undefined behaviour."));
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BugReport *R = new BugReport(*BT_doubleclose,
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BT_doubleclose->getDescription(), N);
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C.emitReport(R);
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}
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return NULL;
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}
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// Close the File Descriptor.
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return state->set<StreamMap>(Sym, StreamState::getClosed(CE));
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}
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void StreamChecker::checkDeadSymbols(SymbolReaper &SymReaper,
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CheckerContext &C) const {
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// TODO: Clean up the state.
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for (SymbolReaper::dead_iterator I = SymReaper.dead_begin(),
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E = SymReaper.dead_end(); I != E; ++I) {
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SymbolRef Sym = *I;
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ProgramStateRef state = C.getState();
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const StreamState *SS = state->get<StreamMap>(Sym);
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if (!SS)
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continue;
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if (SS->isOpened()) {
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ExplodedNode *N = C.generateSink();
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if (N) {
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if (!BT_ResourceLeak)
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BT_ResourceLeak.reset(new BuiltinBug("Resource Leak",
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"Opened File never closed. Potential Resource leak."));
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BugReport *R = new BugReport(*BT_ResourceLeak,
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BT_ResourceLeak->getDescription(), N);
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C.emitReport(R);
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}
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}
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}
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}
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void ento::registerStreamChecker(CheckerManager &mgr) {
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mgr.registerChecker<StreamChecker>();
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}
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