libprocessgroup: Add libcgrouprc am: 098323ba5b

am: 15c6496640

Change-Id: I2e6969425516c307275f94d21d8161999eebecd4

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",
+    ],
+}

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();
+}

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]);
+}

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 {};

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

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:
+    *;
+};