[clang-tidy] Add a close-on-exec check on inotify_init() in Android module.

Summary:
inotify_init() is better to be replaced by inotify_init1() with IN_CLOEXEC flag to avoid file descriptor leakage.

Differential Revision: https://reviews.llvm.org/D35370

llvm-svn: 310861

clang-tools-extra/clang-tidy/android/AndroidTidyModule.cpp

@@ -13,6 +13,7 @@
 #include "CloexecCreatCheck.h"
 #include "CloexecDupCheck.h"
 #include "CloexecFopenCheck.h"
+#include "CloexecInotifyInitCheck.h"
 #include "CloexecMemfdCreateCheck.h"
 #include "CloexecOpenCheck.h"
 #include "CloexecSocketCheck.h"
@@ -30,6 +31,8 @@ public:
     CheckFactories.registerCheck<CloexecCreatCheck>("android-cloexec-creat");
     CheckFactories.registerCheck<CloexecDupCheck>("android-cloexec-dup");
     CheckFactories.registerCheck<CloexecFopenCheck>("android-cloexec-fopen");
+    CheckFactories.registerCheck<CloexecInotifyInitCheck>(
+        "android-cloexec-inotify-init");
     CheckFactories.registerCheck<CloexecMemfdCreateCheck>(
         "android-cloexec-memfd-create");
     CheckFactories.registerCheck<CloexecOpenCheck>("android-cloexec-open");

clang-tools-extra/clang-tidy/android/CMakeLists.txt

@@ -6,6 +6,7 @@ add_clang_library(clangTidyAndroidModule
   CloexecCreatCheck.cpp
   CloexecDupCheck.cpp
   CloexecFopenCheck.cpp
+  CloexecInotifyInitCheck.cpp
   CloexecMemfdCreateCheck.cpp
   CloexecOpenCheck.cpp
   CloexecSocketCheck.cpp

clang-tools-extra/clang-tidy/android/CloexecInotifyInitCheck.cpp

@@ -0,0 +1,34 @@
+//===--- CloexecInotifyInitCheck.cpp - clang-tidy--------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#include "CloexecInotifyInitCheck.h"
+#include "clang/AST/ASTContext.h"
+#include "clang/ASTMatchers/ASTMatchFinder.h"
+
+using namespace clang::ast_matchers;
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+void CloexecInotifyInitCheck::registerMatchers(MatchFinder *Finder) {
+  registerMatchersImpl(
+      Finder, functionDecl(returns(isInteger()), hasName("inotify_init")));
+}
+
+void CloexecInotifyInitCheck::check(const MatchFinder::MatchResult &Result) {
+  replaceFunc(Result, /*WarningMsg=*/
+              "prefer inotify_init() to inotify_init1() "
+              "because inotify_init1() allows IN_CLOEXEC",
+              /*FixMsg=*/"inotify_init1(IN_CLOEXEC)");
+}
+
+} // namespace android
+} // namespace tidy
+} // namespace clang

clang-tools-extra/clang-tidy/android/CloexecInotifyInitCheck.h

@@ -0,0 +1,35 @@
+//===--- CloexecInotifyInitCheck.h - clang-tidy------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT_H
+#define LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT_H
+
+#include "CloexecCheck.h"
+
+namespace clang {
+namespace tidy {
+namespace android {
+
+/// inotify_init() is better to be replaced by inotify_init1().
+///
+/// For the user-facing documentation see:
+/// http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-inotify-init.html
+class CloexecInotifyInitCheck : public CloexecCheck {
+public:
+  CloexecInotifyInitCheck(StringRef Name, ClangTidyContext *Context)
+      : CloexecCheck(Name, Context) {}
+  void registerMatchers(ast_matchers::MatchFinder *Finder) override;
+  void check(const ast_matchers::MatchFinder::MatchResult &Result) override;
+};
+
+} // namespace android
+} // namespace tidy
+} // namespace clang
+
+#endif // LLVM_CLANG_TOOLS_EXTRA_CLANG_TIDY_ANDROID_CLOEXEC_INOTIFY_INIT_H

clang-tools-extra/docs/ReleaseNotes.rst

@@ -75,6 +75,11 @@ Improvements to clang-tidy
 
   Detects usage of ``dup()``.
 
+- New `android-cloexec-inotify-init
+  <http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-inotify-init.html>`_ check
+
+  Detects usage of ``inotify_init()``.
+
 - New `android-cloexec-memfd_create
   <http://clang.llvm.org/extra/clang-tidy/checks/android-cloexec-memfd_create.html>`_ check
 

clang-tools-extra/docs/clang-tidy/checks/android-cloexec-inotify-init.rst

@@ -0,0 +1,17 @@
+.. title:: clang-tidy - android-cloexec-inotify-init
+
+android-cloexec-inotify-init
+============================
+
+The usage of ``inotify_init()`` is not recommended, it's better to use
+``inotify_init1()``.
+
+Examples:
+
+.. code-block:: c++
+
+  inotify_init();
+
+  // becomes
+
+  inotify_init1(IN_CLOEXEC);

clang-tools-extra/docs/clang-tidy/checks/list.rst

@@ -7,6 +7,7 @@ Clang-Tidy Checks
    android-cloexec-creat
    android-cloexec-dup
    android-cloexec-fopen
+   android-cloexec-inotify-init
    android-cloexec-memfd-create
    android-cloexec-open
    android-cloexec-socket

clang-tools-extra/test/clang-tidy/android-cloexec-inotify-init.cpp

@@ -0,0 +1,24 @@
+// RUN: %check_clang_tidy %s android-cloexec-inotify-init %t
+
+extern "C" int inotify_init();
+
+void f() {
+  inotify_init();
+  // CHECK-MESSAGES: :[[@LINE-1]]:3: warning: prefer inotify_init() to inotify_init1() because inotify_init1() allows IN_CLOEXEC [android-cloexec-inotify-init]
+  // CHECK-FIXES: inotify_init1(IN_CLOEXEC);
+}
+
+namespace i {
+int inotify_init();
+void g() {
+  inotify_init();
+}
+} // namespace i
+
+class C {
+public:
+  int inotify_init();
+  void h() {
+    inotify_init();
+  }
+};