1 // MacOSXAPIChecker.h - Checks proper use of various MacOS X APIs --*- C++ -*-//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This defines MacOSXAPIChecker, which is an assortment of checks on calls
11 // to various, widely used Mac OS X functions.
12 //
13 // FIXME: What's currently in BasicObjCFoundationChecks.cpp should be migrated
14 // to here, using the new Checker interface.
15 //
16 //===----------------------------------------------------------------------===//
17
18 #include "ClangSACheckers.h"
19 #include "clang/StaticAnalyzer/Core/Checker.h"
20 #include "clang/StaticAnalyzer/Core/CheckerManager.h"
21 #include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
22 #include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
23 #include "clang/StaticAnalyzer/Core/PathSensitive/GRStateTrait.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "llvm/ADT/SmallString.h"
26 #include "llvm/ADT/StringSwitch.h"
27 #include "llvm/Support/raw_ostream.h"
28
29 using namespace clang;
30 using namespace ento;
31
32 namespace {
33 class MacOSXAPIChecker : public Checker< check::PreStmt<CallExpr> > {
34 mutable llvm::OwningPtr<BugType> BT_dispatchOnce;
35
36 public:
37 void checkPreStmt(const CallExpr *CE, CheckerContext &C) const;
38
39 void CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
40 const IdentifierInfo *FI) const;
41
42 typedef void (MacOSXAPIChecker::*SubChecker)(CheckerContext &,
43 const CallExpr *,
44 const IdentifierInfo *) const;
45 };
46 } //end anonymous namespace
47
48 //===----------------------------------------------------------------------===//
49 // dispatch_once and dispatch_once_f
50 //===----------------------------------------------------------------------===//
51
CheckDispatchOnce(CheckerContext & C,const CallExpr * CE,const IdentifierInfo * FI) const52 void MacOSXAPIChecker::CheckDispatchOnce(CheckerContext &C, const CallExpr *CE,
53 const IdentifierInfo *FI) const {
54 if (CE->getNumArgs() < 1)
55 return;
56
57 // Check if the first argument is stack allocated. If so, issue a warning
58 // because that's likely to be bad news.
59 const GRState *state = C.getState();
60 const MemRegion *R = state->getSVal(CE->getArg(0)).getAsRegion();
61 if (!R || !isa<StackSpaceRegion>(R->getMemorySpace()))
62 return;
63
64 ExplodedNode *N = C.generateSink(state);
65 if (!N)
66 return;
67
68 if (!BT_dispatchOnce)
69 BT_dispatchOnce.reset(new BugType("Improper use of 'dispatch_once'",
70 "Mac OS X API"));
71
72 llvm::SmallString<256> S;
73 llvm::raw_svector_ostream os(S);
74 os << "Call to '" << FI->getName() << "' uses";
75 if (const VarRegion *VR = dyn_cast<VarRegion>(R))
76 os << " the local variable '" << VR->getDecl()->getName() << '\'';
77 else
78 os << " stack allocated memory";
79 os << " for the predicate value. Using such transient memory for "
80 "the predicate is potentially dangerous.";
81 if (isa<VarRegion>(R) && isa<StackLocalsSpaceRegion>(R->getMemorySpace()))
82 os << " Perhaps you intended to declare the variable as 'static'?";
83
84 RangedBugReport *report = new RangedBugReport(*BT_dispatchOnce, os.str(), N);
85 report->addRange(CE->getArg(0)->getSourceRange());
86 C.EmitReport(report);
87 }
88
89 //===----------------------------------------------------------------------===//
90 // Central dispatch function.
91 //===----------------------------------------------------------------------===//
92
checkPreStmt(const CallExpr * CE,CheckerContext & C) const93 void MacOSXAPIChecker::checkPreStmt(const CallExpr *CE,
94 CheckerContext &C) const {
95 // FIXME: This sort of logic is common to several checkers, including
96 // UnixAPIChecker, PthreadLockChecker, and CStringChecker. Should refactor.
97 const GRState *state = C.getState();
98 const Expr *Callee = CE->getCallee();
99 const FunctionDecl *Fn = state->getSVal(Callee).getAsFunctionDecl();
100
101 if (!Fn)
102 return;
103
104 const IdentifierInfo *FI = Fn->getIdentifier();
105 if (!FI)
106 return;
107
108 SubChecker SC =
109 llvm::StringSwitch<SubChecker>(FI->getName())
110 .Cases("dispatch_once", "dispatch_once_f",
111 &MacOSXAPIChecker::CheckDispatchOnce)
112 .Default(NULL);
113
114 if (SC)
115 (this->*SC)(C, CE, FI);
116 }
117
118 //===----------------------------------------------------------------------===//
119 // Registration.
120 //===----------------------------------------------------------------------===//
121
registerMacOSXAPIChecker(CheckerManager & mgr)122 void ento::registerMacOSXAPIChecker(CheckerManager &mgr) {
123 mgr.registerChecker<MacOSXAPIChecker>();
124 }
125