1 /* 2 * Copyright (C) 2017 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #ifndef INCLUDE_PERFETTO_BASE_SCOPED_FILE_H_ 18 #define INCLUDE_PERFETTO_BASE_SCOPED_FILE_H_ 19 20 #include "perfetto/base/build_config.h" 21 22 #include <fcntl.h> 23 #include <stdio.h> 24 25 #if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN) && \ 26 !PERFETTO_BUILDFLAG(PERFETTO_COMPILER_GCC) 27 #include <corecrt_io.h> 28 typedef int mode_t; 29 #else 30 #include <dirent.h> 31 #include <unistd.h> 32 #endif 33 34 #include <string> 35 36 #include "perfetto/base/logging.h" 37 38 namespace perfetto { 39 namespace base { 40 41 constexpr mode_t kInvalidMode = static_cast<mode_t>(-1); 42 43 // RAII classes for auto-releasing fds and dirs. 44 template <typename T, 45 int (*CloseFunction)(T), 46 T InvalidValue, 47 bool CheckClose = true> 48 class ScopedResource { 49 public: t_(t)50 explicit ScopedResource(T t = InvalidValue) : t_(t) {} ScopedResource(ScopedResource && other)51 ScopedResource(ScopedResource&& other) noexcept { 52 t_ = other.t_; 53 other.t_ = InvalidValue; 54 } 55 ScopedResource& operator=(ScopedResource&& other) { 56 reset(other.t_); 57 other.t_ = InvalidValue; 58 return *this; 59 } get()60 T get() const { return t_; } 61 T operator*() const { return t_; } 62 explicit operator bool() const { return t_ != InvalidValue; } 63 void reset(T r = InvalidValue) { 64 if (t_ != InvalidValue) { 65 int res = CloseFunction(t_); 66 if (CheckClose) 67 PERFETTO_CHECK(res == 0); 68 } 69 t_ = r; 70 } release()71 T release() { 72 T t = t_; 73 t_ = InvalidValue; 74 return t; 75 } ~ScopedResource()76 ~ScopedResource() { reset(InvalidValue); } 77 78 private: 79 ScopedResource(const ScopedResource&) = delete; 80 ScopedResource& operator=(const ScopedResource&) = delete; 81 82 T t_; 83 }; 84 85 using ScopedFile = ScopedResource<int, close, -1>; 86 inline static ScopedFile OpenFile(const std::string& path, 87 int flags, 88 mode_t mode = kInvalidMode) { 89 PERFETTO_DCHECK((flags & O_CREAT) == 0 || mode != kInvalidMode); 90 #if PERFETTO_BUILDFLAG(PERFETTO_OS_WIN) 91 ScopedFile fd(open(path.c_str(), flags, mode)); 92 #else 93 // Always open a ScopedFile with O_CLOEXEC so we can safely fork and exec. 94 ScopedFile fd(open(path.c_str(), flags | O_CLOEXEC, mode)); 95 #endif 96 return fd; 97 } 98 #if !PERFETTO_BUILDFLAG(PERFETTO_OS_WIN) 99 using ScopedDir = ScopedResource<DIR*, closedir, nullptr>; 100 #endif 101 102 using ScopedFstream = ScopedResource<FILE*, fclose, nullptr>; 103 104 } // namespace base 105 } // namespace perfetto 106 107 #endif // INCLUDE_PERFETTO_BASE_SCOPED_FILE_H_ 108