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 SRC_TRACING_IPC_POSIX_SHARED_MEMORY_H_ 18 #define SRC_TRACING_IPC_POSIX_SHARED_MEMORY_H_ 19 20 #include "perfetto/base/build_config.h" 21 22 #if PERFETTO_BUILDFLAG(PERFETTO_OS_LINUX) || \ 23 PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID) || \ 24 PERFETTO_BUILDFLAG(PERFETTO_OS_APPLE) || \ 25 PERFETTO_BUILDFLAG(PERFETTO_OS_FUCHSIA) || \ 26 PERFETTO_BUILDFLAG(PERFETTO_OS_WASM) 27 28 #include <stddef.h> 29 30 #include <memory> 31 32 #include "perfetto/base/build_config.h" 33 #include "perfetto/ext/base/scoped_file.h" 34 #include "perfetto/ext/tracing/core/shared_memory.h" 35 36 namespace perfetto { 37 38 // Implements the SharedMemory and its factory for the posix-based transport. 39 class PosixSharedMemory : public SharedMemory { 40 public: 41 class Factory : public SharedMemory::Factory { 42 public: 43 ~Factory() override; 44 std::unique_ptr<SharedMemory> CreateSharedMemory(size_t) override; 45 }; 46 47 // Create a brand new SHM region. 48 static std::unique_ptr<PosixSharedMemory> Create(size_t size); 49 50 // Mmaps a file descriptor to an existing SHM region. If 51 // |require_seals_if_supported| is true and the system supports 52 // memfd_create(), the FD is required to be a sealed memfd with F_SEAL_SEAL, 53 // F_SEAL_GROW, and F_SEAL_SHRINK seals set (otherwise, nullptr is returned). 54 // May also return nullptr if mapping fails for another reason (e.g. OOM). 55 static std::unique_ptr<PosixSharedMemory> AttachToFd( 56 base::ScopedFile, 57 bool require_seals_if_supported = true); 58 59 ~PosixSharedMemory() override; 60 fd()61 int fd() const { return fd_.get(); } 62 63 // SharedMemory implementation. 64 using SharedMemory::start; // Equal priority to const and non-const versions start()65 const void* start() const override { return start_; } size()66 size_t size() const override { return size_; } 67 68 private: 69 static std::unique_ptr<PosixSharedMemory> MapFD(base::ScopedFile, size_t); 70 71 PosixSharedMemory(void* start, size_t size, base::ScopedFile); 72 PosixSharedMemory(const PosixSharedMemory&) = delete; 73 PosixSharedMemory& operator=(const PosixSharedMemory&) = delete; 74 75 void* const start_; 76 const size_t size_; 77 base::ScopedFile fd_; 78 }; 79 80 } // namespace perfetto 81 82 #endif // OS_LINUX || OS_ANDROID || OS_APPLE 83 #endif // SRC_TRACING_IPC_POSIX_SHARED_MEMORY_H_ 84