1 //===--- SignalHandlerCheck.h - clang-tidy ----------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SIGNALHANDLERCHECK_H
10 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SIGNALHANDLERCHECK_H
11 
12 #include "../ClangTidyCheck.h"
13 #include "clang/Analysis/CallGraph.h"
14 #include "llvm/ADT/DepthFirstIterator.h"
15 #include "llvm/ADT/StringSet.h"
16 
17 namespace clang {
18 namespace tidy {
19 namespace bugprone {
20 
21 /// Checker for signal handler functions.
22 ///
23 /// For the user-facing documentation see:
24 /// http://clang.llvm.org/extra/clang-tidy/checks/bugprone/signal-handler-check.html
25 class SignalHandlerCheck : public ClangTidyCheck {
26 public:
27   enum class AsyncSafeFunctionSetKind { Minimal, POSIX };
28 
29   SignalHandlerCheck(StringRef Name, ClangTidyContext *Context);
30   void storeOptions(ClangTidyOptions::OptionMap &Opts) override;
31   bool isLanguageVersionSupported(const LangOptions &LangOpts) const override;
32   void registerMatchers(ast_matchers::MatchFinder *Finder) override;
33   void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
34 
35 private:
36   /// Check if a function is allowed as a signal handler.
37   /// Should test the properties of the function, and check in the code body.
38   /// Should not check function calls in the code (this part is done by the call
39   /// graph scan).
40   /// @param FD The function to check. It may or may not have a definition.
41   /// @param CallOrRef Location of the call to this function (in another
42   /// function) or the reference to the function (if it is used as a registered
43   /// signal handler). This is the location where diagnostics are to be placed.
44   /// @return Returns true if a diagnostic was emitted for this function.
45   bool checkFunction(const FunctionDecl *FD, const Expr *CallOrRef);
46   /// Returns true if a standard library function is considered as
47   /// asynchronous-safe.
48   bool isStandardFunctionAsyncSafe(const FunctionDecl *FD) const;
49   /// Add diagnostic notes to show the call chain of functions from a signal
50   /// handler to a function that is called (directly or indirectly) from it.
51   /// Also add a note to the place where the signal handler is registered.
52   /// @param Itr Position during a call graph depth-first iteration. It contains
53   /// the "path" (call chain) from the signal handler to the actual found
54   /// function call.
55   /// @param HandlerRef Reference to the signal handler function where it is
56   /// registered as signal handler.
57   void reportHandlerChain(const llvm::df_iterator<clang::CallGraphNode *> &Itr,
58                           const DeclRefExpr *HandlerRef);
59 
60   clang::CallGraph CG;
61 
62   AsyncSafeFunctionSetKind AsyncSafeFunctionSet;
63   const llvm::StringSet<> ConformingFunctions;
64 };
65 
66 } // namespace bugprone
67 } // namespace tidy
68 } // namespace clang
69 
70 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_BUGPRONE_SIGNALHANDLERCHECK_H
71