| /* |
| * Copyright 2014 Google, Inc |
| * |
| * 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 <assert.h> |
| #include <dirent.h> |
| #include <errno.h> |
| #include <fcntl.h> |
| #include <inttypes.h> |
| #include <signal.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <sys/stat.h> |
| #include <sys/types.h> |
| #include <unistd.h> |
| |
| #include <chrono> |
| #include <map> |
| #include <memory> |
| #include <mutex> |
| #include <set> |
| #include <string> |
| #include <thread> |
| |
| #include <android-base/file.h> |
| #include <android-base/logging.h> |
| #include <android-base/properties.h> |
| #include <android-base/stringprintf.h> |
| #include <android-base/strings.h> |
| #include <cutils/android_filesystem_config.h> |
| #include <processgroup/processgroup.h> |
| #include <task_profiles.h> |
| |
| using android::base::GetBoolProperty; |
| using android::base::StartsWith; |
| using android::base::StringPrintf; |
| using android::base::WriteStringToFile; |
| |
| using namespace std::chrono_literals; |
| |
| #define PROCESSGROUP_CGROUP_PROCS_FILE "/cgroup.procs" |
| |
| bool CgroupGetControllerPath(const std::string& cgroup_name, std::string* path) { |
| auto controller = CgroupMap::GetInstance().FindController(cgroup_name); |
| |
| if (!controller.HasValue()) { |
| return false; |
| } |
| |
| if (path) { |
| *path = controller.path(); |
| } |
| |
| return true; |
| } |
| |
| static bool CgroupGetMemcgAppsPath(std::string* path) { |
| CgroupController controller = CgroupMap::GetInstance().FindController("memory"); |
| |
| if (!controller.HasValue()) { |
| return false; |
| } |
| |
| if (path) { |
| *path = controller.path(); |
| if (controller.version() == 1) { |
| *path += "/apps"; |
| } |
| } |
| |
| return true; |
| } |
| |
| bool CgroupGetControllerFromPath(const std::string& path, std::string* cgroup_name) { |
| auto controller = CgroupMap::GetInstance().FindControllerByPath(path); |
| |
| if (!controller.HasValue()) { |
| return false; |
| } |
| |
| if (cgroup_name) { |
| *cgroup_name = controller.name(); |
| } |
| |
| return true; |
| } |
| |
| bool CgroupGetAttributePath(const std::string& attr_name, std::string* path) { |
| const TaskProfiles& tp = TaskProfiles::GetInstance(); |
| const IProfileAttribute* attr = tp.GetAttribute(attr_name); |
| |
| if (attr == nullptr) { |
| return false; |
| } |
| |
| if (path) { |
| *path = StringPrintf("%s/%s", attr->controller()->path(), attr->file_name().c_str()); |
| } |
| |
| return true; |
| } |
| |
| bool CgroupGetAttributePathForTask(const std::string& attr_name, int tid, std::string* path) { |
| const TaskProfiles& tp = TaskProfiles::GetInstance(); |
| const IProfileAttribute* attr = tp.GetAttribute(attr_name); |
| |
| if (attr == nullptr) { |
| return false; |
| } |
| |
| if (!attr->GetPathForTask(tid, path)) { |
| PLOG(ERROR) << "Failed to find cgroup for tid " << tid; |
| return false; |
| } |
| |
| return true; |
| } |
| |
| bool UsePerAppMemcg() { |
| bool low_ram_device = GetBoolProperty("ro.config.low_ram", false); |
| return GetBoolProperty("ro.config.per_app_memcg", low_ram_device); |
| } |
| |
| static bool isMemoryCgroupSupported() { |
| static bool memcg_supported = CgroupMap::GetInstance().FindController("memory").IsUsable(); |
| |
| return memcg_supported; |
| } |
| |
| void DropTaskProfilesResourceCaching() { |
| TaskProfiles::GetInstance().DropResourceCaching(ProfileAction::RCT_TASK); |
| TaskProfiles::GetInstance().DropResourceCaching(ProfileAction::RCT_PROCESS); |
| } |
| |
| bool SetProcessProfiles(uid_t uid, pid_t pid, const std::vector<std::string>& profiles) { |
| return TaskProfiles::GetInstance().SetProcessProfiles(uid, pid, profiles, false); |
| } |
| |
| bool SetProcessProfilesCached(uid_t uid, pid_t pid, const std::vector<std::string>& profiles) { |
| return TaskProfiles::GetInstance().SetProcessProfiles(uid, pid, profiles, true); |
| } |
| |
| bool SetTaskProfiles(int tid, const std::vector<std::string>& profiles, bool use_fd_cache) { |
| return TaskProfiles::GetInstance().SetTaskProfiles(tid, profiles, use_fd_cache); |
| } |
| |
| // C wrapper for SetProcessProfiles. |
| // No need to have this in the header file because this function is specifically for crosvm. Crosvm |
| // which is written in Rust has its own declaration of this foreign function and doesn't rely on the |
| // header. See |
| // https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/3574427/5/src/linux/android.rs#12 |
| extern "C" bool android_set_process_profiles(uid_t uid, pid_t pid, size_t num_profiles, |
| const char* profiles[]) { |
| std::vector<std::string> profiles_(num_profiles); |
| for (size_t i = 0; i < num_profiles; i++) { |
| profiles_.emplace_back(profiles[i]); |
| } |
| return SetProcessProfiles(uid, pid, profiles_); |
| } |
| |
| static std::string ConvertUidToPath(const char* cgroup, uid_t uid) { |
| return StringPrintf("%s/uid_%d", cgroup, uid); |
| } |
| |
| static std::string ConvertUidPidToPath(const char* cgroup, uid_t uid, int pid) { |
| return StringPrintf("%s/uid_%d/pid_%d", cgroup, uid, pid); |
| } |
| |
| static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid, unsigned int retries) { |
| int ret = 0; |
| auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, pid); |
| auto uid_path = ConvertUidToPath(cgroup, uid); |
| |
| if (retries == 0) { |
| retries = 1; |
| } |
| |
| while (retries--) { |
| ret = rmdir(uid_pid_path.c_str()); |
| if (!ret || errno != EBUSY) break; |
| std::this_thread::sleep_for(5ms); |
| } |
| |
| return ret; |
| } |
| |
| static bool RemoveUidProcessGroups(const std::string& uid_path) { |
| std::unique_ptr<DIR, decltype(&closedir)> uid(opendir(uid_path.c_str()), closedir); |
| bool empty = true; |
| if (uid != NULL) { |
| dirent* dir; |
| while ((dir = readdir(uid.get())) != nullptr) { |
| if (dir->d_type != DT_DIR) { |
| continue; |
| } |
| |
| if (!StartsWith(dir->d_name, "pid_")) { |
| continue; |
| } |
| |
| auto path = StringPrintf("%s/%s", uid_path.c_str(), dir->d_name); |
| LOG(VERBOSE) << "Removing " << path; |
| if (rmdir(path.c_str()) == -1) { |
| if (errno != EBUSY) { |
| PLOG(WARNING) << "Failed to remove " << path; |
| } |
| empty = false; |
| } |
| } |
| } |
| return empty; |
| } |
| |
| void removeAllProcessGroups() { |
| LOG(VERBOSE) << "removeAllProcessGroups()"; |
| |
| std::vector<std::string> cgroups; |
| std::string path, memcg_apps_path; |
| |
| if (CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &path)) { |
| cgroups.push_back(path); |
| } |
| if (CgroupGetMemcgAppsPath(&memcg_apps_path) && memcg_apps_path != path) { |
| cgroups.push_back(memcg_apps_path); |
| } |
| |
| for (std::string cgroup_root_path : cgroups) { |
| std::unique_ptr<DIR, decltype(&closedir)> root(opendir(cgroup_root_path.c_str()), closedir); |
| if (root == NULL) { |
| PLOG(ERROR) << __func__ << " failed to open " << cgroup_root_path; |
| } else { |
| dirent* dir; |
| while ((dir = readdir(root.get())) != nullptr) { |
| if (dir->d_type != DT_DIR) { |
| continue; |
| } |
| |
| if (!StartsWith(dir->d_name, "uid_")) { |
| continue; |
| } |
| |
| auto path = StringPrintf("%s/%s", cgroup_root_path.c_str(), dir->d_name); |
| if (!RemoveUidProcessGroups(path)) { |
| LOG(VERBOSE) << "Skip removing " << path; |
| continue; |
| } |
| LOG(VERBOSE) << "Removing " << path; |
| if (rmdir(path.c_str()) == -1 && errno != EBUSY) { |
| PLOG(WARNING) << "Failed to remove " << path; |
| } |
| } |
| } |
| } |
| } |
| |
| /** |
| * Process groups are primarily created by the Zygote, meaning that uid/pid groups are created by |
| * the user root. Ownership for the newly created cgroup and all of its files must thus be |
| * transferred for the user/group passed as uid/gid before system_server can properly access them. |
| */ |
| static bool MkdirAndChown(const std::string& path, mode_t mode, uid_t uid, gid_t gid) { |
| if (mkdir(path.c_str(), mode) == -1) { |
| if (errno == EEXIST) { |
| // Directory already exists and permissions have been set at the time it was created |
| return true; |
| } |
| return false; |
| } |
| |
| auto dir = std::unique_ptr<DIR, decltype(&closedir)>(opendir(path.c_str()), closedir); |
| |
| if (dir == NULL) { |
| PLOG(ERROR) << "opendir failed for " << path; |
| goto err; |
| } |
| |
| struct dirent* dir_entry; |
| while ((dir_entry = readdir(dir.get()))) { |
| if (!strcmp("..", dir_entry->d_name)) { |
| continue; |
| } |
| |
| std::string file_path = path + "/" + dir_entry->d_name; |
| |
| if (lchown(file_path.c_str(), uid, gid) < 0) { |
| PLOG(ERROR) << "lchown failed for " << file_path; |
| goto err; |
| } |
| |
| if (fchmodat(AT_FDCWD, file_path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) { |
| PLOG(ERROR) << "fchmodat failed for " << file_path; |
| goto err; |
| } |
| } |
| |
| return true; |
| err: |
| int saved_errno = errno; |
| rmdir(path.c_str()); |
| errno = saved_errno; |
| |
| return false; |
| } |
| |
| // Returns number of processes killed on success |
| // Returns 0 if there are no processes in the process cgroup left to kill |
| // Returns -1 on error |
| static int DoKillProcessGroupOnce(const char* cgroup, uid_t uid, int initialPid, int signal) { |
| auto path = ConvertUidPidToPath(cgroup, uid, initialPid) + PROCESSGROUP_CGROUP_PROCS_FILE; |
| std::unique_ptr<FILE, decltype(&fclose)> fd(fopen(path.c_str(), "re"), fclose); |
| if (!fd) { |
| if (errno == ENOENT) { |
| // This happens when process is already dead |
| return 0; |
| } |
| PLOG(WARNING) << __func__ << " failed to open process cgroup uid " << uid << " pid " |
| << initialPid; |
| return -1; |
| } |
| |
| // We separate all of the pids in the cgroup into those pids that are also the leaders of |
| // process groups (stored in the pgids set) and those that are not (stored in the pids set). |
| std::set<pid_t> pgids; |
| pgids.emplace(initialPid); |
| std::set<pid_t> pids; |
| |
| pid_t pid; |
| int processes = 0; |
| while (fscanf(fd.get(), "%d\n", &pid) == 1 && pid >= 0) { |
| processes++; |
| if (pid == 0) { |
| // Should never happen... but if it does, trying to kill this |
| // will boomerang right back and kill us! Let's not let that happen. |
| LOG(WARNING) << "Yikes, we've been told to kill pid 0! How about we don't do that?"; |
| continue; |
| } |
| pid_t pgid = getpgid(pid); |
| if (pgid == -1) PLOG(ERROR) << "getpgid(" << pid << ") failed"; |
| if (pgid == pid) { |
| pgids.emplace(pid); |
| } else { |
| pids.emplace(pid); |
| } |
| } |
| |
| // Erase all pids that will be killed when we kill the process groups. |
| for (auto it = pids.begin(); it != pids.end();) { |
| pid_t pgid = getpgid(*it); |
| if (pgids.count(pgid) == 1) { |
| it = pids.erase(it); |
| } else { |
| ++it; |
| } |
| } |
| |
| // Kill all process groups. |
| for (const auto pgid : pgids) { |
| LOG(VERBOSE) << "Killing process group " << -pgid << " in uid " << uid |
| << " as part of process cgroup " << initialPid; |
| |
| if (kill(-pgid, signal) == -1 && errno != ESRCH) { |
| PLOG(WARNING) << "kill(" << -pgid << ", " << signal << ") failed"; |
| } |
| } |
| |
| // Kill remaining pids. |
| for (const auto pid : pids) { |
| LOG(VERBOSE) << "Killing pid " << pid << " in uid " << uid << " as part of process cgroup " |
| << initialPid; |
| |
| if (kill(pid, signal) == -1 && errno != ESRCH) { |
| PLOG(WARNING) << "kill(" << pid << ", " << signal << ") failed"; |
| } |
| } |
| |
| return feof(fd.get()) ? processes : -1; |
| } |
| |
| static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries, |
| int* max_processes) { |
| std::string hierarchy_root_path; |
| CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &hierarchy_root_path); |
| const char* cgroup = hierarchy_root_path.c_str(); |
| |
| std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now(); |
| |
| if (max_processes != nullptr) { |
| *max_processes = 0; |
| } |
| |
| int retry = retries; |
| int processes; |
| while ((processes = DoKillProcessGroupOnce(cgroup, uid, initialPid, signal)) > 0) { |
| if (max_processes != nullptr && processes > *max_processes) { |
| *max_processes = processes; |
| } |
| LOG(VERBOSE) << "Killed " << processes << " processes for processgroup " << initialPid; |
| if (retry > 0) { |
| std::this_thread::sleep_for(5ms); |
| --retry; |
| } else { |
| break; |
| } |
| } |
| |
| if (processes < 0) { |
| PLOG(ERROR) << "Error encountered killing process cgroup uid " << uid << " pid " |
| << initialPid; |
| return -1; |
| } |
| |
| std::chrono::steady_clock::time_point end = std::chrono::steady_clock::now(); |
| auto ms = std::chrono::duration_cast<std::chrono::milliseconds>(end - start).count(); |
| |
| // We only calculate the number of 'processes' when killing the processes. |
| // In the retries == 0 case, we only kill the processes once and therefore |
| // will not have waited then recalculated how many processes are remaining |
| // after the first signals have been sent. |
| // Logging anything regarding the number of 'processes' here does not make sense. |
| |
| if (processes == 0) { |
| if (retries > 0) { |
| LOG(INFO) << "Successfully killed process cgroup uid " << uid << " pid " << initialPid |
| << " in " << static_cast<int>(ms) << "ms"; |
| } |
| |
| int err = RemoveProcessGroup(cgroup, uid, initialPid, retries); |
| |
| if (isMemoryCgroupSupported() && UsePerAppMemcg()) { |
| std::string memcg_apps_path; |
| if (CgroupGetMemcgAppsPath(&memcg_apps_path) && |
| RemoveProcessGroup(memcg_apps_path.c_str(), uid, initialPid, retries) < 0) { |
| return -1; |
| } |
| } |
| |
| return err; |
| } else { |
| if (retries > 0) { |
| LOG(ERROR) << "Failed to kill process cgroup uid " << uid << " pid " << initialPid |
| << " in " << static_cast<int>(ms) << "ms, " << processes |
| << " processes remain"; |
| } |
| return -1; |
| } |
| } |
| |
| int killProcessGroup(uid_t uid, int initialPid, int signal, int* max_processes) { |
| return KillProcessGroup(uid, initialPid, signal, 40 /*retries*/, max_processes); |
| } |
| |
| int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_processes) { |
| return KillProcessGroup(uid, initialPid, signal, 0 /*retries*/, max_processes); |
| } |
| |
| static int createProcessGroupInternal(uid_t uid, int initialPid, std::string cgroup, |
| bool activate_controllers) { |
| auto uid_path = ConvertUidToPath(cgroup.c_str(), uid); |
| |
| struct stat cgroup_stat; |
| mode_t cgroup_mode = 0750; |
| uid_t cgroup_uid = AID_SYSTEM; |
| gid_t cgroup_gid = AID_SYSTEM; |
| int ret = 0; |
| |
| if (stat(cgroup.c_str(), &cgroup_stat) < 0) { |
| PLOG(ERROR) << "Failed to get stats for " << cgroup; |
| } else { |
| cgroup_mode = cgroup_stat.st_mode; |
| cgroup_uid = cgroup_stat.st_uid; |
| cgroup_gid = cgroup_stat.st_gid; |
| } |
| |
| if (!MkdirAndChown(uid_path, cgroup_mode, cgroup_uid, cgroup_gid)) { |
| PLOG(ERROR) << "Failed to make and chown " << uid_path; |
| return -errno; |
| } |
| if (activate_controllers) { |
| ret = CgroupMap::GetInstance().ActivateControllers(uid_path); |
| if (ret) { |
| LOG(ERROR) << "Failed to activate controllers in " << uid_path; |
| return ret; |
| } |
| } |
| |
| auto uid_pid_path = ConvertUidPidToPath(cgroup.c_str(), uid, initialPid); |
| |
| if (!MkdirAndChown(uid_pid_path, cgroup_mode, cgroup_uid, cgroup_gid)) { |
| PLOG(ERROR) << "Failed to make and chown " << uid_pid_path; |
| return -errno; |
| } |
| |
| auto uid_pid_procs_file = uid_pid_path + PROCESSGROUP_CGROUP_PROCS_FILE; |
| |
| if (!WriteStringToFile(std::to_string(initialPid), uid_pid_procs_file)) { |
| ret = -errno; |
| PLOG(ERROR) << "Failed to write '" << initialPid << "' to " << uid_pid_procs_file; |
| } |
| |
| return ret; |
| } |
| |
| int createProcessGroup(uid_t uid, int initialPid, bool memControl) { |
| std::string cgroup; |
| |
| if (memControl && !UsePerAppMemcg()) { |
| PLOG(ERROR) << "service memory controls are used without per-process memory cgroup support"; |
| return -EINVAL; |
| } |
| |
| if (std::string memcg_apps_path; |
| isMemoryCgroupSupported() && UsePerAppMemcg() && CgroupGetMemcgAppsPath(&memcg_apps_path)) { |
| // Note by bvanassche: passing 'false' as fourth argument below implies that the v1 |
| // hierarchy is used. It is not clear to me whether the above conditions guarantee that the |
| // v1 hierarchy is used. |
| int ret = createProcessGroupInternal(uid, initialPid, memcg_apps_path, false); |
| if (ret != 0) { |
| return ret; |
| } |
| } |
| |
| CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &cgroup); |
| return createProcessGroupInternal(uid, initialPid, cgroup, true); |
| } |
| |
| static bool SetProcessGroupValue(int tid, const std::string& attr_name, int64_t value) { |
| if (!isMemoryCgroupSupported()) { |
| PLOG(ERROR) << "Memcg is not mounted."; |
| return false; |
| } |
| |
| std::string path; |
| if (!CgroupGetAttributePathForTask(attr_name, tid, &path)) { |
| PLOG(ERROR) << "Failed to find attribute '" << attr_name << "'"; |
| return false; |
| } |
| |
| if (!WriteStringToFile(std::to_string(value), path)) { |
| PLOG(ERROR) << "Failed to write '" << value << "' to " << path; |
| return false; |
| } |
| return true; |
| } |
| |
| bool setProcessGroupSwappiness(uid_t, int pid, int swappiness) { |
| return SetProcessGroupValue(pid, "MemSwappiness", swappiness); |
| } |
| |
| bool setProcessGroupSoftLimit(uid_t, int pid, int64_t soft_limit_in_bytes) { |
| return SetProcessGroupValue(pid, "MemSoftLimit", soft_limit_in_bytes); |
| } |
| |
| bool setProcessGroupLimit(uid_t, int pid, int64_t limit_in_bytes) { |
| return SetProcessGroupValue(pid, "MemLimit", limit_in_bytes); |
| } |
| |
| bool getAttributePathForTask(const std::string& attr_name, int tid, std::string* path) { |
| return CgroupGetAttributePathForTask(attr_name, tid, path); |
| } |