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1 //===--- CloexecCheck.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 /// \file
10 /// This file contains the declaration of the CloexecCheck class, which is the
11 /// base class for all of the close-on-exec checks in Android module.
12 ///
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
16 #define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
17 
18 #include "../ClangTidyCheck.h"
19 
20 namespace clang {
21 namespace tidy {
22 namespace android {
23 
24 /// The base class for all close-on-exec checks in Android module.
25 /// To be specific, there are some functions that need the close-on-exec flag to
26 /// prevent the file descriptor leakage on fork+exec and this class provides
27 /// utilities to identify and fix these C functions.
28 class CloexecCheck : public ClangTidyCheck {
29 public:
CloexecCheck(StringRef Name,ClangTidyContext * Context)30   CloexecCheck(StringRef Name, ClangTidyContext *Context)
31       : ClangTidyCheck(Name, Context) {}
32 
33 protected:
34   void
35   registerMatchersImpl(ast_matchers::MatchFinder *Finder,
36                        ast_matchers::internal::Matcher<FunctionDecl> Function);
37 
38   /// Currently, we have three types of fixes.
39   ///
40   /// Type1 is to insert the necessary macro flag in the flag argument. For
41   /// example, 'O_CLOEXEC' is required in function 'open()', so
42   /// \code
43   ///   open(file, O_RDONLY);
44   /// \endcode
45   /// should be
46   /// \code
47   ///   open(file, O_RDONLY | O_CLOEXE);
48   /// \endcode
49   ///
50   /// \param [out] Result MatchResult from AST matcher.
51   /// \param MacroFlag The macro name of the flag.
52   /// \param ArgPos The 0-based position of the flag argument.
53   void insertMacroFlag(const ast_matchers::MatchFinder::MatchResult &Result,
54                        StringRef MacroFlag, int ArgPos);
55 
56   /// Type2 is to replace the API to another function that has required the
57   /// ability. For example:
58   /// \code
59   ///   creat(path, mode);
60   /// \endcode
61   /// should be
62   /// \code
63   ///   open(path, O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC, mode)
64   /// \endcode
65   ///
66   /// \param [out] Result MatchResult from AST matcher.
67   /// \param WarningMsg The warning message.
68   /// \param FixMsg The fix message.
69   void replaceFunc(const ast_matchers::MatchFinder::MatchResult &Result,
70                    StringRef WarningMsg, StringRef FixMsg);
71 
72   /// Type3 is also to add a flag to the corresponding argument, but this time,
73   /// the flag is some string and each char represents a mode rather than a
74   /// macro. For example, 'fopen' needs char 'e' in its mode argument string, so
75   /// \code
76   ///   fopen(in_file, "r");
77   /// \endcode
78   /// should be
79   /// \code
80   ///   fopen(in_file, "re");
81   /// \endcode
82   ///
83   /// \param [out] Result MatchResult from AST matcher.
84   /// \param Mode The required mode char.
85   /// \param ArgPos The 0-based position of the flag argument.
86   void insertStringFlag(const ast_matchers::MatchFinder::MatchResult &Result,
87                         const char Mode, const int ArgPos);
88 
89   /// Helper function to get the spelling of a particular argument.
90   StringRef getSpellingArg(const ast_matchers::MatchFinder::MatchResult &Result,
91                            int N) const;
92 
93   /// Binding name of the FuncDecl of a function call.
94   static const char *FuncDeclBindingStr;
95 
96   /// Binding name of the function call expression.
97   static const char *FuncBindingStr;
98 };
99 
100 } // namespace android
101 } // namespace tidy
102 } // namespace clang
103 
104 #endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_H
105