libprocessgroup: Add libcgrouprc
This module is an LL-NDK library that can be loaded by
modules that link to libprocessgroup (which is in VNDK).
This module defines APIs that reads cgroups.rc file
programatically. Internally, it uses libcgrouprc_format to
do so.
Test: builds
Bug: 123664216
Change-Id: I9c13c0528461758154e23cbab3a94ade7fb351ee
diff --git a/libprocessgroup/cgrouprc/Android.bp b/libprocessgroup/cgrouprc/Android.bp
new file mode 100644
index 0000000..f5ff7eb
--- /dev/null
+++ b/libprocessgroup/cgrouprc/Android.bp
@@ -0,0 +1,52 @@
+// 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",
+ ],
+}
diff --git a/libprocessgroup/cgrouprc/cgroup_controller.cpp b/libprocessgroup/cgrouprc/cgroup_controller.cpp
new file mode 100644
index 0000000..d064d31
--- /dev/null
+++ b/libprocessgroup/cgrouprc/cgroup_controller.cpp
@@ -0,0 +1,38 @@
+/*
+ * 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();
+}
diff --git a/libprocessgroup/cgrouprc/cgroup_file.cpp b/libprocessgroup/cgrouprc/cgroup_file.cpp
new file mode 100644
index 0000000..e26d841
--- /dev/null
+++ b/libprocessgroup/cgrouprc/cgroup_file.cpp
@@ -0,0 +1,106 @@
+/*
+ * 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]);
+}
diff --git a/libprocessgroup/cgrouprc/cgrouprc_internal.h b/libprocessgroup/cgrouprc/cgrouprc_internal.h
new file mode 100644
index 0000000..cd02f03
--- /dev/null
+++ b/libprocessgroup/cgrouprc/cgrouprc_internal.h
@@ -0,0 +1,24 @@
+/*
+ * 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 {};
diff --git a/libprocessgroup/cgrouprc/include/android/cgrouprc.h b/libprocessgroup/cgrouprc/include/android/cgrouprc.h
new file mode 100644
index 0000000..4edd239
--- /dev/null
+++ b/libprocessgroup/cgrouprc/include/android/cgrouprc.h
@@ -0,0 +1,84 @@
+/*
+ * 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
diff --git a/libprocessgroup/cgrouprc/libcgrouprc.map.txt b/libprocessgroup/cgrouprc/libcgrouprc.map.txt
new file mode 100644
index 0000000..91df392
--- /dev/null
+++ b/libprocessgroup/cgrouprc/libcgrouprc.map.txt
@@ -0,0 +1,11 @@
+LIBCGROUPRC { # introduced=29
+ global:
+ ACgroupFile_getVersion;
+ ACgroupFile_getControllerCount;
+ ACgroupFile_getController;
+ ACgroupController_getVersion;
+ ACgroupController_getName;
+ ACgroupController_getPath;
+ local:
+ *;
+};