Revert "libprocessgroup: Remove cgroup.rc file"

Revert submission 3212512

Reason for revert: Droidmonitor created revert due to b/372273614. Will be verifying through ABTD before submission.

Reverted changes: /q/submissionid:3212512

Change-Id: I37568516e973cb940f1229d52f94b8dc801da2ab
diff --git a/libprocessgroup/util/Android.bp b/libprocessgroup/util/Android.bp
index 1c74d4e..54ba69b 100644
--- a/libprocessgroup/util/Android.bp
+++ b/libprocessgroup/util/Android.bp
@@ -37,16 +37,8 @@
         "include",
     ],
     srcs: [
-        "cgroup_controller.cpp",
-        "cgroup_descriptor.cpp",
         "util.cpp",
     ],
-    shared_libs: [
-        "libbase",
-    ],
-    static_libs: [
-        "libjsoncpp",
-    ],
     defaults: ["libprocessgroup_build_flags_cc"],
 }
 
diff --git a/libprocessgroup/util/cgroup_controller.cpp b/libprocessgroup/util/cgroup_controller.cpp
deleted file mode 100644
index fb41680..0000000
--- a/libprocessgroup/util/cgroup_controller.cpp
+++ /dev/null
@@ -1,55 +0,0 @@
-/*
- * 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 <processgroup/cgroup_controller.h>
-
-#include <cstring>
-
-CgroupController::CgroupController(uint32_t version, uint32_t flags, const std::string& name,
-                                   const std::string& path, uint32_t max_activation_depth)
-    : version_(version), flags_(flags), max_activation_depth_(max_activation_depth) {
-    // strlcpy isn't available on host. Although there is an implementation
-    // in licutils, libcutils itself depends on libcgrouprc_format, causing
-    // a circular dependency.
-    strncpy(name_, name.c_str(), sizeof(name_) - 1);
-    name_[sizeof(name_) - 1] = '\0';
-    strncpy(path_, path.c_str(), sizeof(path_) - 1);
-    path_[sizeof(path_) - 1] = '\0';
-}
-
-uint32_t CgroupController::version() const {
-    return version_;
-}
-
-uint32_t CgroupController::flags() const {
-    return flags_;
-}
-
-uint32_t CgroupController::max_activation_depth() const {
-    return max_activation_depth_;
-}
-
-const char* CgroupController::name() const {
-    return name_;
-}
-
-const char* CgroupController::path() const {
-    return path_;
-}
-
-void CgroupController::set_flags(uint32_t flags) {
-    flags_ = flags;
-}
\ No newline at end of file
diff --git a/libprocessgroup/util/cgroup_descriptor.cpp b/libprocessgroup/util/cgroup_descriptor.cpp
deleted file mode 100644
index 4d3347f..0000000
--- a/libprocessgroup/util/cgroup_descriptor.cpp
+++ /dev/null
@@ -1,38 +0,0 @@
-/*
- * Copyright (C) 2024 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 <processgroup/cgroup_descriptor.h>
-
-#include <processgroup/util.h>  // For flag values
-
-CgroupDescriptor::CgroupDescriptor(uint32_t version, const std::string& name,
-                                   const std::string& path, mode_t mode, const std::string& uid,
-                                   const std::string& gid, uint32_t flags,
-                                   uint32_t max_activation_depth)
-    : controller_(version, flags, name, path, max_activation_depth),
-      mode_(mode),
-      uid_(uid),
-      gid_(gid) {}
-
-void CgroupDescriptor::set_mounted(bool mounted) {
-    uint32_t flags = controller_.flags();
-    if (mounted) {
-        flags |= CGROUPRC_CONTROLLER_FLAG_MOUNTED;
-    } else {
-        flags &= ~CGROUPRC_CONTROLLER_FLAG_MOUNTED;
-    }
-    controller_.set_flags(flags);
-}
diff --git a/libprocessgroup/util/include/processgroup/cgroup_controller.h b/libprocessgroup/util/include/processgroup/cgroup_controller.h
deleted file mode 100644
index fe6a829..0000000
--- a/libprocessgroup/util/include/processgroup/cgroup_controller.h
+++ /dev/null
@@ -1,47 +0,0 @@
-/*
- * 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 <cstddef>
-#include <cstdint>
-#include <string>
-
-// Minimal controller description
-struct CgroupController {
-  public:
-    CgroupController() = default;
-    CgroupController(uint32_t version, uint32_t flags, const std::string& name,
-                     const std::string& path, uint32_t max_activation_depth);
-
-    uint32_t version() const;
-    uint32_t flags() const;
-    uint32_t max_activation_depth() const;
-    const char* name() const;
-    const char* path() const;
-
-    void set_flags(uint32_t flags);
-
-  private:
-    static constexpr size_t CGROUP_NAME_BUF_SZ = 16;
-    static constexpr size_t CGROUP_PATH_BUF_SZ = 32;
-
-    uint32_t version_ = 0;
-    uint32_t flags_ = 0;
-    uint32_t max_activation_depth_ = UINT32_MAX;
-    char name_[CGROUP_NAME_BUF_SZ] = {};
-    char path_[CGROUP_PATH_BUF_SZ] = {};
-};
\ No newline at end of file
diff --git a/libprocessgroup/util/include/processgroup/cgroup_descriptor.h b/libprocessgroup/util/include/processgroup/cgroup_descriptor.h
deleted file mode 100644
index 1afd2ee..0000000
--- a/libprocessgroup/util/include/processgroup/cgroup_descriptor.h
+++ /dev/null
@@ -1,45 +0,0 @@
-/*
- * 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 <cstdint>
-#include <string>
-
-#include <sys/stat.h>
-
-#include <processgroup/cgroup_controller.h>
-
-// Complete controller description for mounting cgroups
-class CgroupDescriptor {
-  public:
-    CgroupDescriptor(uint32_t version, const std::string& name, const std::string& path,
-                     mode_t mode, const std::string& uid, const std::string& gid, uint32_t flags,
-                     uint32_t max_activation_depth);
-
-    const CgroupController* controller() const { return &controller_; }
-    mode_t mode() const { return mode_; }
-    std::string uid() const { return uid_; }
-    std::string gid() const { return gid_; }
-
-    void set_mounted(bool mounted);
-
-  private:
-    CgroupController controller_;
-    mode_t mode_ = 0;
-    std::string uid_;
-    std::string gid_;
-};
diff --git a/libprocessgroup/util/include/processgroup/util.h b/libprocessgroup/util/include/processgroup/util.h
index d592a63..8d013af 100644
--- a/libprocessgroup/util/include/processgroup/util.h
+++ b/libprocessgroup/util/include/processgroup/util.h
@@ -16,18 +16,10 @@
 
 #pragma once
 
-#include <map>
 #include <string>
 
-#include "cgroup_descriptor.h"
-
-// Duplicated from cgrouprc.h. Don't depend on libcgrouprc here.
-#define CGROUPRC_CONTROLLER_FLAG_MOUNTED 0x1
-#define CGROUPRC_CONTROLLER_FLAG_NEEDS_ACTIVATION 0x2
-#define CGROUPRC_CONTROLLER_FLAG_OPTIONAL 0x4
+namespace util {
 
 unsigned int GetCgroupDepth(const std::string& controller_root, const std::string& cgroup_path);
 
-using CgroupControllerName = std::string;
-using CgroupDescriptorMap = std::map<CgroupControllerName, CgroupDescriptor>;
-bool ReadDescriptors(CgroupDescriptorMap* descriptors);
+}  // namespace util
diff --git a/libprocessgroup/util/tests/util.cpp b/libprocessgroup/util/tests/util.cpp
index 6caef8e..1de7d6f 100644
--- a/libprocessgroup/util/tests/util.cpp
+++ b/libprocessgroup/util/tests/util.cpp
@@ -18,6 +18,8 @@
 
 #include "gtest/gtest.h"
 
+using util::GetCgroupDepth;
+
 TEST(EmptyInputs, bothEmpty) {
     EXPECT_EQ(GetCgroupDepth({}, {}), 0);
 }
diff --git a/libprocessgroup/util/util.cpp b/libprocessgroup/util/util.cpp
index bff4c6f..9b88a22 100644
--- a/libprocessgroup/util/util.cpp
+++ b/libprocessgroup/util/util.cpp
@@ -18,33 +18,9 @@
 
 #include <algorithm>
 #include <iterator>
-#include <optional>
-#include <string_view>
-
-#include <mntent.h>
-
-#include <android-base/file.h>
-#include <android-base/logging.h>
-#include <android-base/properties.h>
-#include <android-base/stringprintf.h>
-#include <json/reader.h>
-#include <json/value.h>
-
-#include "../build_flags.h"
-#include "../internal.h"
-
-using android::base::GetUintProperty;
 
 namespace {
 
-constexpr const char* CGROUPS_DESC_FILE = "/etc/cgroups.json";
-constexpr const char* CGROUPS_DESC_VENDOR_FILE = "/vendor/etc/cgroups.json";
-constexpr const char* TEMPLATE_CGROUPS_DESC_API_FILE = "/etc/task_profiles/cgroups_%u.json";
-
-// This should match the publicly declared value in processgroup.h,
-// but we don't want this library to depend on libprocessgroup.
-constexpr std::string CGROUPV2_HIERARCHY_NAME_INTERNAL = "cgroup2";
-
 const char SEP = '/';
 
 std::string DeduplicateAndTrimSeparators(const std::string& path) {
@@ -66,135 +42,9 @@
     return ret;
 }
 
-void MergeCgroupToDescriptors(CgroupDescriptorMap* descriptors, const Json::Value& cgroup,
-                              const std::string& name, const std::string& root_path,
-                              int cgroups_version) {
-    const std::string cgroup_path = cgroup["Path"].asString();
-    std::string path;
-
-    if (!root_path.empty()) {
-        path = root_path;
-        if (cgroup_path != ".") {
-            path += "/";
-            path += cgroup_path;
-        }
-    } else {
-        path = cgroup_path;
-    }
-
-    uint32_t controller_flags = 0;
-
-    if (cgroup["NeedsActivation"].isBool() && cgroup["NeedsActivation"].asBool()) {
-        controller_flags |= CGROUPRC_CONTROLLER_FLAG_NEEDS_ACTIVATION;
-    }
-
-    if (cgroup["Optional"].isBool() && cgroup["Optional"].asBool()) {
-        controller_flags |= CGROUPRC_CONTROLLER_FLAG_OPTIONAL;
-    }
-
-    uint32_t max_activation_depth = UINT32_MAX;
-    if (cgroup.isMember("MaxActivationDepth")) {
-        max_activation_depth = cgroup["MaxActivationDepth"].asUInt();
-    }
-
-    CgroupDescriptor descriptor(
-            cgroups_version, name, path, std::strtoul(cgroup["Mode"].asString().c_str(), 0, 8),
-            cgroup["UID"].asString(), cgroup["GID"].asString(), controller_flags,
-            max_activation_depth);
-
-    auto iter = descriptors->find(name);
-    if (iter == descriptors->end()) {
-        descriptors->emplace(name, descriptor);
-    } else {
-        iter->second = descriptor;
-    }
-}
-
-bool ReadDescriptorsFromFile(const std::string& file_name, CgroupDescriptorMap* descriptors) {
-    static constexpr bool force_memcg_v2 = android::libprocessgroup_flags::force_memcg_v2();
-    std::vector<CgroupDescriptor> result;
-    std::string json_doc;
-
-    if (!android::base::ReadFileToString(file_name, &json_doc)) {
-        PLOG(ERROR) << "Failed to read task profiles from " << file_name;
-        return false;
-    }
-
-    Json::CharReaderBuilder builder;
-    std::unique_ptr<Json::CharReader> reader(builder.newCharReader());
-    Json::Value root;
-    std::string errorMessage;
-    if (!reader->parse(&*json_doc.begin(), &*json_doc.end(), &root, &errorMessage)) {
-        LOG(ERROR) << "Failed to parse cgroups description: " << errorMessage;
-        return false;
-    }
-
-    if (root.isMember("Cgroups")) {
-        const Json::Value& cgroups = root["Cgroups"];
-        for (Json::Value::ArrayIndex i = 0; i < cgroups.size(); ++i) {
-            std::string name = cgroups[i]["Controller"].asString();
-
-            if (force_memcg_v2 && name == "memory") continue;
-
-            MergeCgroupToDescriptors(descriptors, cgroups[i], name, "", 1);
-        }
-    }
-
-    bool memcgv2_present = false;
-    std::string root_path;
-    if (root.isMember("Cgroups2")) {
-        const Json::Value& cgroups2 = root["Cgroups2"];
-        root_path = cgroups2["Path"].asString();
-        MergeCgroupToDescriptors(descriptors, cgroups2, CGROUPV2_HIERARCHY_NAME_INTERNAL, "", 2);
-
-        const Json::Value& childGroups = cgroups2["Controllers"];
-        for (Json::Value::ArrayIndex i = 0; i < childGroups.size(); ++i) {
-            std::string name = childGroups[i]["Controller"].asString();
-
-            if (force_memcg_v2 && name == "memory") memcgv2_present = true;
-
-            MergeCgroupToDescriptors(descriptors, childGroups[i], name, root_path, 2);
-        }
-    }
-
-    if (force_memcg_v2 && !memcgv2_present) {
-        LOG(INFO) << "Forcing memcg to v2 hierarchy";
-        Json::Value memcgv2;
-        memcgv2["Controller"] = "memory";
-        memcgv2["NeedsActivation"] = true;
-        memcgv2["Path"] = ".";
-        memcgv2["Optional"] = true;  // In case of cgroup_disabled=memory, so we can still boot
-        MergeCgroupToDescriptors(descriptors, memcgv2, "memory",
-                                 root_path.empty() ? CGROUP_V2_ROOT_DEFAULT : root_path, 2);
-    }
-
-    return true;
-}
-
-using MountDir = std::string;
-using MountOpts = std::string;
-static std::optional<std::map<MountDir, MountOpts>> ReadCgroupV1Mounts() {
-    FILE* fp = setmntent("/proc/mounts", "r");
-    if (fp == nullptr) {
-        PLOG(ERROR) << "Failed to read mounts";
-        return std::nullopt;
-    }
-
-    std::map<MountDir, MountOpts> mounts;
-    const std::string_view CGROUP_V1_TYPE = "cgroup";
-    for (mntent* mentry = getmntent(fp); mentry != nullptr; mentry = getmntent(fp)) {
-        if (mentry->mnt_type && CGROUP_V1_TYPE == mentry->mnt_type &&
-            mentry->mnt_dir && mentry->mnt_opts) {
-            mounts[mentry->mnt_dir] = mentry->mnt_opts;
-        }
-    }
-    endmntent(fp);
-
-    return mounts;
-}
-
 }  // anonymous namespace
 
+namespace util {
 
 unsigned int GetCgroupDepth(const std::string& controller_root, const std::string& cgroup_path) {
     const std::string deduped_root = DeduplicateAndTrimSeparators(controller_root);
@@ -206,47 +56,4 @@
     return std::count(deduped_path.begin() + deduped_root.size(), deduped_path.end(), SEP);
 }
 
-bool ReadDescriptors(CgroupDescriptorMap* descriptors) {
-    // load system cgroup descriptors
-    if (!ReadDescriptorsFromFile(CGROUPS_DESC_FILE, descriptors)) {
-        return false;
-    }
-
-    // load API-level specific system cgroups descriptors if available
-    unsigned int api_level = GetUintProperty<unsigned int>("ro.product.first_api_level", 0);
-    if (api_level > 0) {
-        std::string api_cgroups_path =
-                android::base::StringPrintf(TEMPLATE_CGROUPS_DESC_API_FILE, api_level);
-        if (!access(api_cgroups_path.c_str(), F_OK) || errno != ENOENT) {
-            if (!ReadDescriptorsFromFile(api_cgroups_path, descriptors)) {
-                return false;
-            }
-        }
-    }
-
-    // load vendor cgroup descriptors if the file exists
-    if (!access(CGROUPS_DESC_VENDOR_FILE, F_OK) &&
-        !ReadDescriptorsFromFile(CGROUPS_DESC_VENDOR_FILE, descriptors)) {
-        return false;
-    }
-
-    // check for v1 mount/usability status
-    std::optional<std::map<MountDir, MountOpts>> v1Mounts;
-    for (auto& [name, descriptor] : *descriptors) {
-        const CgroupController* const controller = descriptor.controller();
-
-        if (controller->version() != 1) continue;
-
-        // Read only once, and only if we have at least one v1 controller
-        if (!v1Mounts) {
-            v1Mounts = ReadCgroupV1Mounts();
-            if (!v1Mounts) return false;
-        }
-
-        if (const auto it = v1Mounts->find(controller->path()); it != v1Mounts->end()) {
-            if (it->second.contains(controller->name())) descriptor.set_mounted(true);
-        }
-    }
-
-    return true;
-}
+}  // namespace util