libprocessgroup: Add libcgrouprc (098323ba) · Commits · e / os / android_system_core

libprocessgroup/cgrouprc/Android.bp

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		// Copyright (C) 2019 The Android Open Source Project
		//
		// Licensed under the Apache License, Version 2.0 (the "License");
		// you may not use this file except in compliance with the License.
		// You may obtain a copy of the License at
		//
		// http://www.apache.org/licenses/LICENSE-2.0
		//
		// Unless required by applicable law or agreed to in writing, software
		// distributed under the License is distributed on an "AS IS" BASIS,
		// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		// See the License for the specific language governing permissions and
		// limitations under the License.

		cc_library_shared {
		name: "libcgrouprc",
		host_supported: true,
		recovery_available: true,
		srcs: [
		"cgroup_controller.cpp",
		"cgroup_file.cpp",
		],
		cflags: [
		"-Wall",
		"-Werror",
		],
		export_include_dirs: [
		"include",
		],
		header_libs: [
		"libprocessgroup_headers",
		],
		shared_libs: [
		"libbase",
		],
		static_libs: [
		"libcgrouprc_format",
		],
		stubs: {
		symbol_file: "libcgrouprc.map.txt",
		versions: ["29"],
		},
		version_script: "libcgrouprc.map.txt",
		}

		llndk_library {
		name: "libcgrouprc",
		symbol_file: "libcgrouprc.map.txt",
		export_include_dirs: [
		"include",
		],
		}

libprocessgroup/cgrouprc/cgroup_controller.cpp

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		/*
		* Copyright (C) 2019 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#include <android-base/logging.h>
		#include <android/cgrouprc.h>

		#include "cgrouprc_internal.h"

		// All ACgroupController_* functions implicitly convert the pointer back
		// to the original CgroupController pointer before invoking the member functions.

		uint32_t ACgroupController_getVersion(const ACgroupController* controller) {
		CHECK(controller != nullptr);
		return controller->version();
		}

		const char* ACgroupController_getName(const ACgroupController* controller) {
		CHECK(controller != nullptr);
		return controller->name();
		}

		const char* ACgroupController_getPath(const ACgroupController* controller) {
		CHECK(controller != nullptr);
		return controller->path();
		}

libprocessgroup/cgrouprc/cgroup_file.cpp

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		/*
		* Copyright (C) 2019 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#include <sys/mman.h>
		#include <sys/stat.h>

		#include <memory>

		#include <android-base/logging.h>
		#include <android-base/stringprintf.h>
		#include <android-base/unique_fd.h>
		#include <android/cgrouprc.h>
		#include <processgroup/processgroup.h>

		#include "cgrouprc_internal.h"

		using android::base::StringPrintf;
		using android::base::unique_fd;

		using android::cgrouprc::format::CgroupController;
		using android::cgrouprc::format::CgroupFile;

		static CgroupFile* LoadRcFile() {
		struct stat sb;

		unique_fd fd(TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_RDONLY \| O_CLOEXEC)));
		if (fd < 0) {
		PLOG(ERROR) << "open() failed for " << CGROUPS_RC_PATH;
		return nullptr;
		}

		if (fstat(fd, &sb) < 0) {
		PLOG(ERROR) << "fstat() failed for " << CGROUPS_RC_PATH;
		return nullptr;
		}

		size_t file_size = sb.st_size;
		if (file_size < sizeof(CgroupFile)) {
		LOG(ERROR) << "Invalid file format " << CGROUPS_RC_PATH;
		return nullptr;
		}

		CgroupFile* file_data = (CgroupFile*)mmap(nullptr, file_size, PROT_READ, MAP_SHARED, fd, 0);
		if (file_data == MAP_FAILED) {
		PLOG(ERROR) << "Failed to mmap " << CGROUPS_RC_PATH;
		return nullptr;
		}

		if (file_data->version_ != CgroupFile::FILE_CURR_VERSION) {
		LOG(ERROR) << CGROUPS_RC_PATH << " file version mismatch";
		munmap(file_data, file_size);
		return nullptr;
		}

		auto expected = sizeof(CgroupFile) + file_data->controller_count_ * sizeof(CgroupController);
		if (file_size != expected) {
		LOG(ERROR) << CGROUPS_RC_PATH << " file has invalid size, expected " << expected
		<< ", actual " << file_size;
		munmap(file_data, file_size);
		return nullptr;
		}

		return file_data;
		}

		static CgroupFile* GetInstance() {
		// Deliberately leak this object (not munmap) to avoid a race between destruction on
		// process exit and concurrent access from another thread.
		static auto* file = LoadRcFile();
		return file;
		}

		uint32_t ACgroupFile_getVersion() {
		auto file = GetInstance();
		if (file == nullptr) return 0;
		return file->version_;
		}

		uint32_t ACgroupFile_getControllerCount() {
		auto file = GetInstance();
		if (file == nullptr) return 0;
		return file->controller_count_;
		}

		const ACgroupController* ACgroupFile_getController(uint32_t index) {
		auto file = GetInstance();
		if (file == nullptr) return nullptr;
		CHECK(index < file->controller_count_);
		// Although the object is not actually an ACgroupController object, all ACgroupController_*
		// functions implicitly convert ACgroupController* back to CgroupController* before invoking
		// member functions.
		return static_cast<ACgroupController*>(&file->controllers_[index]);
		}

libprocessgroup/cgrouprc/cgrouprc_internal.h

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		/*
		* Copyright (C) 2019 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#pragma once

		#include <android/cgrouprc.h>

		#include <processgroup/format/cgroup_controller.h>
		#include <processgroup/format/cgroup_file.h>

		struct ACgroupController : android::cgrouprc::format::CgroupController {};

libprocessgroup/cgrouprc/include/android/cgrouprc.h

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		/*
		* Copyright (C) 2019 The Android Open Source Project
		*
		* Licensed under the Apache License, Version 2.0 (the "License");
		* you may not use this file except in compliance with the License.
		* You may obtain a copy of the License at
		*
		* http://www.apache.org/licenses/LICENSE-2.0
		*
		* Unless required by applicable law or agreed to in writing, software
		* distributed under the License is distributed on an "AS IS" BASIS,
		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
		* See the License for the specific language governing permissions and
		* limitations under the License.
		*/

		#pragma once

		#include <stdint.h>

		__BEGIN_DECLS

		// For host builds, __INTRODUCED_IN is not defined.
		#ifndef __INTRODUCED_IN
		#define __INTRODUCED_IN(x)
		#endif

		struct ACgroupController;
		typedef struct ACgroupController ACgroupController;

		#if __ANDROID_API__ >= __ANDROID_API_Q__

		// ACgroupFile

		/**
		* Returns file version. See android::cgrouprc::format::CgroupFile for a list of valid versions
		* for the file.
		* If ACgroupFile_init() isn't called, initialization will be done first.
		* If initialization failed, return 0.
		*/
		__attribute__((warn_unused_result)) uint32_t ACgroupFile_getVersion() __INTRODUCED_IN(29);

		/**
		* Returns the number of controllers.
		* If ACgroupFile_init() isn't called, initialization will be done first.
		* If initialization failed, return 0.
		*/
		__attribute__((warn_unused_result)) uint32_t ACgroupFile_getControllerCount() __INTRODUCED_IN(29);

		/**
		* Returns the controller at the given index.
		* Returnss nullptr if the given index exceeds getControllerCount().
		* If ACgroupFile_init() isn't called, initialization will be done first.
		* If initialization failed, return 0.
		*/
		__attribute__((warn_unused_result)) const ACgroupController* ACgroupFile_getController(
		uint32_t index) __INTRODUCED_IN(29);

		// ACgroupController

		/**
		* Returns the version of the given controller.
		* If the given controller is null, return 0.
		*/
		__attribute__((warn_unused_result)) uint32_t ACgroupController_getVersion(const ACgroupController*)
		__INTRODUCED_IN(29);

		/**
		* Returns the name of the given controller.
		* If the given controller is null, return nullptr.
		*/
		__attribute__((warn_unused_result)) const char* ACgroupController_getName(const ACgroupController*)
		__INTRODUCED_IN(29);

		/**
		* Returns the path of the given controller.
		* If the given controller is null, return nullptr.
		*/
		__attribute__((warn_unused_result)) const char* ACgroupController_getPath(const ACgroupController*)
		__INTRODUCED_IN(29);

		__END_DECLS

		#endif