libprocessgroup: Add support for task profiles
Abstract usage of cgroups into task profiles that allows for changes
in cgroup hierarchy and version without affecting framework codebase.
Rework current processgroup and sched_policy API function implementations
to use task profiles instead of hardcoded paths and attributes.
Mount cgroups using information from cgroups.json rather than from init.rc
Exempt-From-Owner-Approval: already approved in internal master
Bug: 111307099
Test: builds, boots
Change-Id: If5532d6dc570add825cebd5b5148e00c7d688e32
Merged-In: If5532d6dc570add825cebd5b5148e00c7d688e32
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
diff --git a/libprocessgroup/cgroup_map.cpp b/libprocessgroup/cgroup_map.cpp
new file mode 100644
index 0000000..1b5f217
--- /dev/null
+++ b/libprocessgroup/cgroup_map.cpp
@@ -0,0 +1,405 @@
+/*
+ * 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.
+ */
+
+//#define LOG_NDEBUG 0
+#define LOG_TAG "libprocessgroup"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <pwd.h>
+#include <sys/mman.h>
+#include <sys/mount.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#include <regex>
+
+#include <android-base/file.h>
+#include <android-base/logging.h>
+#include <android-base/properties.h>
+#include <android-base/stringprintf.h>
+#include <android-base/unique_fd.h>
+#include <cgroup_map.h>
+#include <json/reader.h>
+#include <json/value.h>
+#include <processgroup/processgroup.h>
+
+using android::base::GetBoolProperty;
+using android::base::StringPrintf;
+using android::base::unique_fd;
+
+static constexpr const char* CGROUPS_DESC_FILE = "/etc/cgroups.json";
+
+static constexpr const char* CGROUP_PROCS_FILE = "/cgroup.procs";
+static constexpr const char* CGROUP_TASKS_FILE = "/tasks";
+static constexpr const char* CGROUP_TASKS_FILE_V2 = "/cgroup.tasks";
+
+static bool Mkdir(const std::string& path, mode_t mode, const std::string& uid,
+ const std::string& gid) {
+ if (mode == 0) {
+ mode = 0755;
+ }
+
+ if (mkdir(path.c_str(), mode) != 0) {
+ /* chmod in case the directory already exists */
+ if (errno == EEXIST) {
+ if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
+ // /acct is a special case when the directory already exists
+ // TODO: check if file mode is already what we want instead of using EROFS
+ if (errno != EROFS) {
+ PLOG(ERROR) << "fchmodat() failed for " << path;
+ return false;
+ }
+ }
+ } else {
+ PLOG(ERROR) << "mkdir() failed for " << path;
+ return false;
+ }
+ }
+
+ passwd* uid_pwd = nullptr;
+ passwd* gid_pwd = nullptr;
+
+ if (!uid.empty()) {
+ uid_pwd = getpwnam(uid.c_str());
+ if (!uid_pwd) {
+ PLOG(ERROR) << "Unable to decode UID for '" << uid << "'";
+ return false;
+ }
+
+ if (!gid.empty()) {
+ gid_pwd = getpwnam(gid.c_str());
+ if (!gid_pwd) {
+ PLOG(ERROR) << "Unable to decode GID for '" << gid << "'";
+ return false;
+ }
+ }
+ }
+
+ if (uid_pwd && lchown(path.c_str(), uid_pwd->pw_uid, gid_pwd ? gid_pwd->pw_uid : -1) < 0) {
+ PLOG(ERROR) << "lchown() failed for " << path;
+ return false;
+ }
+
+ /* chown may have cleared S_ISUID and S_ISGID, chmod again */
+ if (mode & (S_ISUID | S_ISGID)) {
+ if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
+ PLOG(ERROR) << "fchmodat() failed for " << path;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+static bool ReadDescriptors(std::map<std::string, CgroupDescriptor>* descriptors) {
+ std::vector<CgroupDescriptor> result;
+ std::string json_doc;
+
+ if (!android::base::ReadFileToString(CGROUPS_DESC_FILE, &json_doc)) {
+ LOG(ERROR) << "Failed to read task profiles from " << CGROUPS_DESC_FILE;
+ return false;
+ }
+
+ Json::Reader reader;
+ Json::Value root;
+ if (!reader.parse(json_doc, root)) {
+ LOG(ERROR) << "Failed to parse cgroups description: " << reader.getFormattedErrorMessages();
+ return false;
+ }
+
+ Json::Value cgroups = root["Cgroups"];
+ for (Json::Value::ArrayIndex i = 0; i < cgroups.size(); ++i) {
+ std::string name = cgroups[i]["Controller"].asString();
+ descriptors->emplace(std::make_pair(
+ name,
+ CgroupDescriptor(1, name, cgroups[i]["Path"].asString(), cgroups[i]["Mode"].asInt(),
+ cgroups[i]["UID"].asString(), cgroups[i]["GID"].asString())));
+ }
+
+ Json::Value cgroups2 = root["Cgroups2"];
+ descriptors->emplace(std::make_pair(
+ CGROUPV2_CONTROLLER_NAME,
+ CgroupDescriptor(2, CGROUPV2_CONTROLLER_NAME, cgroups2["Path"].asString(),
+ cgroups2["Mode"].asInt(), cgroups2["UID"].asString(),
+ cgroups2["GID"].asString())));
+
+ return true;
+}
+
+static bool SetupCgroup(const CgroupDescriptor& descriptor) {
+ const CgroupController* controller = descriptor.controller();
+
+ // mkdir <path> [mode] [owner] [group]
+ if (!Mkdir(controller->path(), descriptor.mode(), descriptor.uid(), descriptor.gid())) {
+ PLOG(ERROR) << "Failed to create directory for " << controller->name() << " cgroup";
+ return false;
+ }
+
+ int result;
+ if (controller->version() == 2) {
+ result = mount("none", controller->path(), "cgroup2", MS_NODEV | MS_NOEXEC | MS_NOSUID,
+ nullptr);
+ } else {
+ // Unfortunately historically cpuset controller was mounted using a mount command
+ // different from all other controllers. This results in controller attributes not
+ // to be prepended with controller name. For example this way instead of
+ // /dev/cpuset/cpuset.cpus the attribute becomes /dev/cpuset/cpus which is what
+ // the system currently expects.
+ if (!strcmp(controller->name(), "cpuset")) {
+ // mount cpuset none /dev/cpuset nodev noexec nosuid
+ result = mount("none", controller->path(), controller->name(),
+ MS_NODEV | MS_NOEXEC | MS_NOSUID, nullptr);
+ } else {
+ // mount cgroup none <path> nodev noexec nosuid <controller>
+ result = mount("none", controller->path(), "cgroup", MS_NODEV | MS_NOEXEC | MS_NOSUID,
+ controller->name());
+ }
+ }
+
+ if (result < 0) {
+ PLOG(ERROR) << "Failed to mount " << controller->name() << " cgroup";
+ return false;
+ }
+
+ return true;
+}
+
+static bool WriteRcFile(const std::map<std::string, CgroupDescriptor>& descriptors) {
+ std::string cgroup_rc_path = StringPrintf("%s/%s", CGROUPS_RC_DIR, CgroupMap::CGROUPS_RC_FILE);
+ unique_fd fd(TEMP_FAILURE_RETRY(open(cgroup_rc_path.c_str(),
+ O_CREAT | O_WRONLY | O_TRUNC | O_CLOEXEC,
+ S_IRUSR | S_IRGRP | S_IROTH)));
+ if (fd < 0) {
+ PLOG(ERROR) << "open() failed for " << cgroup_rc_path;
+ return false;
+ }
+
+ CgroupFile fl;
+ fl.version_ = CgroupFile::FILE_CURR_VERSION;
+ fl.controller_count_ = descriptors.size();
+ int ret = TEMP_FAILURE_RETRY(write(fd, &fl, sizeof(fl)));
+ if (ret < 0) {
+ PLOG(ERROR) << "write() failed for " << cgroup_rc_path;
+ return false;
+ }
+
+ for (const auto& [name, descriptor] : descriptors) {
+ ret = TEMP_FAILURE_RETRY(write(fd, descriptor.controller(), sizeof(CgroupController)));
+ if (ret < 0) {
+ PLOG(ERROR) << "write() failed for " << cgroup_rc_path;
+ return false;
+ }
+ }
+
+ return true;
+}
+
+CgroupController::CgroupController(uint32_t version, const std::string& name,
+ const std::string& path) {
+ version_ = version;
+ 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';
+}
+
+std::string CgroupController::GetTasksFilePath(const std::string& path) const {
+ std::string tasks_path = path_;
+
+ if (!path.empty()) {
+ tasks_path += "/" + path;
+ }
+ return (version_ == 1) ? tasks_path + CGROUP_TASKS_FILE : tasks_path + CGROUP_TASKS_FILE_V2;
+}
+
+std::string CgroupController::GetProcsFilePath(const std::string& path, uid_t uid,
+ pid_t pid) const {
+ std::string proc_path(path_);
+ proc_path.append("/").append(path);
+ proc_path = regex_replace(proc_path, std::regex("<uid>"), std::to_string(uid));
+ proc_path = regex_replace(proc_path, std::regex("<pid>"), std::to_string(pid));
+
+ return proc_path.append(CGROUP_PROCS_FILE);
+}
+
+bool CgroupController::GetTaskGroup(int tid, std::string* group) const {
+ std::string file_name = StringPrintf("/proc/%d/cgroup", tid);
+ std::string content;
+ if (!android::base::ReadFileToString(file_name, &content)) {
+ LOG(ERROR) << "Failed to read " << file_name;
+ return false;
+ }
+
+ // if group is null and tid exists return early because
+ // user is not interested in cgroup membership
+ if (group == nullptr) {
+ return true;
+ }
+
+ std::string cg_tag = StringPrintf(":%s:", name_);
+ size_t start_pos = content.find(cg_tag);
+ if (start_pos == std::string::npos) {
+ return false;
+ }
+
+ start_pos += cg_tag.length() + 1; // skip '/'
+ size_t end_pos = content.find('\n', start_pos);
+ if (end_pos == std::string::npos) {
+ *group = content.substr(start_pos, std::string::npos);
+ } else {
+ *group = content.substr(start_pos, end_pos - start_pos);
+ }
+
+ return true;
+}
+
+CgroupDescriptor::CgroupDescriptor(uint32_t version, const std::string& name,
+ const std::string& path, mode_t mode, const std::string& uid,
+ const std::string& gid)
+ : controller_(version, name, path), mode_(mode), uid_(uid), gid_(gid) {}
+
+CgroupMap::CgroupMap() : cg_file_data_(nullptr), cg_file_size_(0) {
+ if (!LoadRcFile()) {
+ PLOG(ERROR) << "CgroupMap::LoadRcFile called for [" << getpid() << "] failed";
+ }
+}
+
+CgroupMap::~CgroupMap() {
+ if (cg_file_data_) {
+ munmap(cg_file_data_, cg_file_size_);
+ cg_file_data_ = nullptr;
+ cg_file_size_ = 0;
+ }
+}
+
+CgroupMap& CgroupMap::GetInstance() {
+ static CgroupMap instance;
+ return instance;
+}
+
+bool CgroupMap::LoadRcFile() {
+ struct stat sb;
+
+ if (cg_file_data_) {
+ // Data already initialized
+ return true;
+ }
+
+ std::string cgroup_rc_path = StringPrintf("%s/%s", CGROUPS_RC_DIR, CGROUPS_RC_FILE);
+ unique_fd fd(TEMP_FAILURE_RETRY(open(cgroup_rc_path.c_str(), O_RDONLY | O_CLOEXEC)));
+ if (fd < 0) {
+ PLOG(ERROR) << "open() failed for " << cgroup_rc_path;
+ return false;
+ }
+
+ if (fstat(fd, &sb) < 0) {
+ PLOG(ERROR) << "fstat() failed for " << cgroup_rc_path;
+ return false;
+ }
+
+ cg_file_size_ = sb.st_size;
+ if (cg_file_size_ < sizeof(CgroupFile)) {
+ PLOG(ERROR) << "Invalid file format " << cgroup_rc_path;
+ return false;
+ }
+
+ cg_file_data_ = (CgroupFile*)mmap(nullptr, cg_file_size_, PROT_READ, MAP_SHARED, fd, 0);
+ if (cg_file_data_ == MAP_FAILED) {
+ PLOG(ERROR) << "Failed to mmap " << cgroup_rc_path;
+ return false;
+ }
+
+ if (cg_file_data_->version_ != CgroupFile::FILE_CURR_VERSION) {
+ PLOG(ERROR) << cgroup_rc_path << " file version mismatch";
+ return false;
+ }
+
+ return true;
+}
+
+void CgroupMap::Print() {
+ LOG(INFO) << "File version = " << cg_file_data_->version_;
+ LOG(INFO) << "File controller count = " << cg_file_data_->controller_count_;
+
+ LOG(INFO) << "Mounted cgroups:";
+ CgroupController* controller = (CgroupController*)(cg_file_data_ + 1);
+ for (int i = 0; i < cg_file_data_->controller_count_; i++, controller++) {
+ LOG(INFO) << "\t" << controller->name() << " ver " << controller->version() << " path "
+ << controller->path();
+ }
+}
+
+bool CgroupMap::SetupCgroups() {
+ std::map<std::string, CgroupDescriptor> descriptors;
+
+ // load cgroups.json file
+ if (!ReadDescriptors(&descriptors)) {
+ PLOG(ERROR) << "Failed to load cgroup description file";
+ return false;
+ }
+
+ // setup cgroups
+ for (const auto& [name, descriptor] : descriptors) {
+ if (!SetupCgroup(descriptor)) {
+ // issue a warning and proceed with the next cgroup
+ // TODO: mark the descriptor as invalid and skip it in WriteRcFile()
+ LOG(WARNING) << "Failed to setup " << name << " cgroup";
+ }
+ }
+
+ // mkdir <CGROUPS_RC_DIR> 0711 system system
+ if (!Mkdir(CGROUPS_RC_DIR, 0711, "system", "system")) {
+ PLOG(ERROR) << "Failed to create directory for <CGROUPS_RC_FILE> file";
+ return false;
+ }
+
+ // Generate <CGROUPS_RC_FILE> file which can be directly mmapped into
+ // process memory. This optimizes performance, memory usage
+ // and limits infrormation shared with unprivileged processes
+ // to the minimum subset of information from cgroups.json
+ if (!WriteRcFile(descriptors)) {
+ LOG(ERROR) << "Failed to write " << CGROUPS_RC_FILE << " file";
+ return false;
+ }
+
+ std::string cgroup_rc_path = StringPrintf("%s/%s", CGROUPS_RC_DIR, CGROUPS_RC_FILE);
+ // chmod 0644 <cgroup_rc_path>
+ if (fchmodat(AT_FDCWD, cgroup_rc_path.c_str(), 0644, AT_SYMLINK_NOFOLLOW) < 0) {
+ LOG(ERROR) << "fchmodat() failed";
+ return false;
+ }
+
+ return true;
+}
+
+const CgroupController* CgroupMap::FindController(const std::string& name) const {
+ if (!cg_file_data_) {
+ return nullptr;
+ }
+
+ // skip the file header to get to the first controller
+ CgroupController* controller = (CgroupController*)(cg_file_data_ + 1);
+ for (int i = 0; i < cg_file_data_->controller_count_; i++, controller++) {
+ if (name == controller->name()) {
+ return controller;
+ }
+ }
+
+ return nullptr;
+}