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