Revert^3 "libprocessgroup: uid/pid hierarchy for cgroup v2" (088924af) · Commits · e / os / android_system_core

libprocessgroup/processgroup.cpp

+32 −89

Original line number	Diff line number	Diff line
		@@ -131,25 +131,13 @@ 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;
		}
		static int RemoveProcessGroup(const char* cgroup, uid_t uid, int pid) {
		int ret;

		while (retries--) {
		auto uid_pid_path = ConvertUidPidToPath(cgroup, uid, pid);
		ret = rmdir(uid_pid_path.c_str());
		if (!ret \|\| errno != EBUSY) break;
		std::this_thread::sleep_for(5ms);
		}

		// With the exception of boot or shutdown, system uid_ folders are always populated. Spinning
		// here would needlessly delay most pid removals. Additionally, once empty a uid_ cgroup won't
		// have processes hanging on it (we've already spun for all its pid_), so there's no need to
		// spin anyway.
		auto uid_path = ConvertUidToPath(cgroup, uid);
		rmdir(uid_path.c_str());

		return ret;
		@@ -188,7 +176,7 @@ void removeAllProcessGroups() {
		std::vector<std::string> cgroups;
		std::string path;

		if (CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &path)) {
		if (CgroupGetControllerPath("cpuacct", &path)) {
		cgroups.push_back(path);
		}
		if (CgroupGetControllerPath("memory", &path)) {
		@@ -224,51 +212,21 @@ void removeAllProcessGroups() {
		}
		}

		/**
		* 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 && errno != EEXIST) {
		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:
		if (chown(path.c_str(), uid, gid) == -1) {
		int saved_errno = errno;
		rmdir(path.c_str());
		errno = saved_errno;

		return false;
		}

		return true;
		}

		// 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
		@@ -344,9 +302,17 @@ static int DoKillProcessGroupOnce(const char* cgroup, uid_t uid, int initialPid,

		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::string cpuacct_path;
		std::string memory_path;

		CgroupGetControllerPath("cpuacct", &cpuacct_path);
		CgroupGetControllerPath("memory", &memory_path);
		memory_path += "/apps";

		const char* cgroup =
		(!access(ConvertUidPidToPath(cpuacct_path.c_str(), uid, initialPid).c_str(), F_OK))
		? cpuacct_path.c_str()
		: memory_path.c_str();

		std::chrono::steady_clock::time_point start = std::chrono::steady_clock::now();

		@@ -389,17 +355,7 @@ static int KillProcessGroup(uid_t uid, int initialPid, int signal, int retries,
		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 memory_path;
		CgroupGetControllerPath("memory", &memory_path);
		memory_path += "/apps";
		if (RemoveProcessGroup(memory_path.c_str(), uid, initialPid, retries)) return -1;
		}

		return err;
		return RemoveProcessGroup(cgroup, uid, initialPid);
		} else {
		if (retries > 0) {
		LOG(ERROR) << "Failed to kill process cgroup uid " << uid << " pid " << initialPid
		@@ -418,7 +374,15 @@ int killProcessGroupOnce(uid_t uid, int initialPid, int signal, int* max_process
		return KillProcessGroup(uid, initialPid, signal, 0 /retries/, max_processes);
		}

		static int createProcessGroupInternal(uid_t uid, int initialPid, std::string cgroup) {
		int createProcessGroup(uid_t uid, int initialPid, bool memControl) {
		std::string cgroup;
		if (isMemoryCgroupSupported() && (memControl \|\| UsePerAppMemcg())) {
		CgroupGetControllerPath("memory", &cgroup);
		cgroup += "/apps";
		} else {
		CgroupGetControllerPath("cpuacct", &cgroup);
		}

		auto uid_path = ConvertUidToPath(cgroup.c_str(), uid);

		if (!MkdirAndChown(uid_path, 0750, AID_SYSTEM, AID_SYSTEM)) {
		@@ -444,27 +408,6 @@ static int createProcessGroupInternal(uid_t uid, int initialPid, std::string cgr
		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 (isMemoryCgroupSupported() && UsePerAppMemcg()) {
		CgroupGetControllerPath("memory", &cgroup);
		cgroup += "/apps";
		int ret = createProcessGroupInternal(uid, initialPid, cgroup);
		if (ret != 0) {
		return ret;
		}
		}

		CgroupGetControllerPath(CGROUPV2_CONTROLLER_NAME, &cgroup);
		return createProcessGroupInternal(uid, initialPid, cgroup);
		}

		static bool SetProcessGroupValue(int tid, const std::string& attr_name, int64_t value) {
		if (!isMemoryCgroupSupported()) {
		PLOG(ERROR) << "Memcg is not mounted.";

libprocessgroup/profiles/cgroups.json

+5 −0

Original line number	Diff line number	Diff line
		@@ -14,6 +14,11 @@
		"UID": "system",
		"GID": "system"
		},
		{
		"Controller": "cpuacct",
		"Path": "/acct",
		"Mode": "0555"
		},
		{
		"Controller": "cpuset",
		"Path": "/dev/cpuset",

libprocessgroup/profiles/cgroups.recovery.json

+7 −0

Original line number	Diff line number	Diff line
		{
		"Cgroups": [
		{
		"Controller": "cpuacct",
		"Path": "/acct",
		"Mode": "0555"
		}
		]
		}