/*
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* Copyright (C) 2017 The Android Open Source Project
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "src/tracing/ipc/posix_shared_memory.h"
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#include <fcntl.h>
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#include <stdint.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sys/mman.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <memory>
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#include <utility>
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#include "perfetto/base/build_config.h"
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#include "perfetto/base/logging.h"
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#include "perfetto/base/temp_file.h"
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#if PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
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#include <linux/memfd.h>
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#include <sys/syscall.h>
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#endif
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namespace perfetto {
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// static
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std::unique_ptr<PosixSharedMemory> PosixSharedMemory::Create(size_t size) {
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base::ScopedFile fd;
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#if PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
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bool is_memfd = false;
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fd.reset(static_cast<int>(syscall(__NR_memfd_create, "perfetto_shmem",
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MFD_CLOEXEC | MFD_ALLOW_SEALING)));
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is_memfd = !!fd;
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if (!fd) {
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// TODO: if this fails on Android we should fall back on ashmem.
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PERFETTO_DPLOG("memfd_create() failed");
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}
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#endif
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if (!fd)
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fd = base::TempFile::CreateUnlinked().ReleaseFD();
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PERFETTO_CHECK(fd);
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int res = ftruncate(fd.get(), static_cast<off_t>(size));
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PERFETTO_CHECK(res == 0);
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#if PERFETTO_BUILDFLAG(PERFETTO_OS_ANDROID)
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if (is_memfd) {
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res = fcntl(*fd, F_ADD_SEALS, F_SEAL_SHRINK | F_SEAL_GROW | F_SEAL_SEAL);
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PERFETTO_DCHECK(res == 0);
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}
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#endif
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return MapFD(std::move(fd), size);
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}
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// static
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std::unique_ptr<PosixSharedMemory> PosixSharedMemory::AttachToFd(
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base::ScopedFile fd) {
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struct stat stat_buf = {};
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int res = fstat(fd.get(), &stat_buf);
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PERFETTO_CHECK(res == 0 && stat_buf.st_size > 0);
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return MapFD(std::move(fd), static_cast<size_t>(stat_buf.st_size));
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}
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// static
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std::unique_ptr<PosixSharedMemory> PosixSharedMemory::MapFD(base::ScopedFile fd,
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size_t size) {
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PERFETTO_DCHECK(fd);
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PERFETTO_DCHECK(size > 0);
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void* start =
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mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, fd.get(), 0);
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PERFETTO_CHECK(start != MAP_FAILED);
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return std::unique_ptr<PosixSharedMemory>(
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new PosixSharedMemory(start, size, std::move(fd)));
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}
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PosixSharedMemory::PosixSharedMemory(void* start,
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size_t size,
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base::ScopedFile fd)
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: start_(start), size_(size), fd_(std::move(fd)) {}
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PosixSharedMemory::~PosixSharedMemory() {
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munmap(start(), size());
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}
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PosixSharedMemory::Factory::~Factory() {}
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std::unique_ptr<SharedMemory> PosixSharedMemory::Factory::CreateSharedMemory(
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size_t size) {
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return PosixSharedMemory::Create(size);
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}
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} // namespace perfetto
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