8 #include <unordered_set>
14 #include "service-listener.h"
15 #include "service-constants.h"
19 * This header defines service_record, a data record maintaining information about a service,
20 * and service_set, a set of interdependent service records. It also defines some associated
21 * types and exceptions.
25 * Services have both a current state and a desired state. The desired state can be
26 * either STARTED or STOPPED. The current state can also be STARTING or STOPPING.
27 * A service can be "pinned" in either the STARTED or STOPPED states to prevent it
28 * from leaving that state until it is unpinned.
30 * The total state is a combination of the two, current and desired:
31 * STOPPED/STOPPED : stopped and will remain stopped
32 * STOPPED/STARTED : stopped (pinned), must be unpinned to start
33 * STARTING/STARTED : starting, but not yet started. Dependencies may also be starting.
34 * STARTING/STOPPED : as above, but the service will be stopped again as soon as it has
36 * STARTED/STARTED : running and will continue running.
37 * STARTED/STOPPED : started (pinned), must be unpinned to stop
38 * STOPPING/STOPPED : stopping and will stop. Dependents may be stopping.
39 * STOPPING/STARTED : as above, but the service will be re-started again once it stops.
41 * A scripted service is in the STARTING/STOPPING states during the script execution.
42 * A process service is in the STOPPING state when it has been signalled to stop, and is
43 * in the STARTING state when waiting for dependencies to start or for the exec() call in
44 * the forked child to complete and return a status.
46 * Acquisition/release:
48 * Each service has a dependent-count ("required_by"). This starts at 0, adds 1 if the
49 * service has explicitly been started (i.e. "start_explicit" is true), and adds 1 for
50 * each dependent service which is not STOPPED (including dependents with a soft dependency).
51 * When required_by transitions to 0, the service is stopped (unless it is pinned). When
52 * require_by transitions from 0, the service is started (unless pinned).
54 * So, in general, the dependent-count determines the desired state (STARTED if the count
55 * is greater than 0, otherwise STOPPED). However, a service can be issued a stop-and-take
56 * down order (via `stop(true)'); this will first stop dependent services, which may restart
57 * and cancel the stop of the former service. Finally, a service can be force-stopped, which
58 * means that its stop process cannot be cancelled (though it may still be put in a desired
59 * state of STARTED, meaning it will start immediately upon stopping).
63 * A service may be "pinned" in either STARTED or STOPPED states (or even both). Once it
64 * reaches a pinned state, a service will not leave that state, though its desired state
65 * may still be set. (Note that pinning prevents, but never causes, state transition).
67 * The priority of the different state deciders is:
70 * - desired state (which is manipulated by require/release operations)
72 * So a forced stop cannot occur until the service is not pinned started, for instance.
74 * Two-phase transition
75 * --------------------
76 * Transition between states occurs in two phases: propagation and execution. In both phases
77 * a linked-list queue is used to keep track of which services need processing; this avoids
78 * recursion (which would be of unknown depth and therefore liable to stack overflow).
80 * In the propagation phase, acquisition/release messages are processed, and desired state may be
81 * altered accordingly. Start and stop requests are also propagated in this phase. The state may
82 * be set to STARTING or STOPPING to reflect the desired state, but will never be set to STARTED
83 * or STOPPED (that happens in the execution phase).
85 * Propagation variables:
86 * prop_acquire: the service has transitioned to an acquired state and must issue an acquire
88 * prop_release: the service has transitioned to a released state and must issue a release on
91 * prop_start: the service should start
92 * prop_stop: the service should stop
94 * Note that "prop_acquire"/"prop_release" form a pair which cannot both be set at the same time
95 * which is enforced via explicit checks. For "prop_start"/"prop_stop" this occurs implicitly.
97 * In the execution phase, actions are taken to achieve the desired state. Actual state may
98 * transition according to the current and desired states. Processes can be sent signals, etc
99 * in order to stop them. A process can restart if it stops, but it does so by raising prop_start
100 * which needs to be processed in a second transition phase. Seeing as starting never causes
101 * another process to stop, the transition-execute-transition cycle always ends at the 2nd
102 * transition stage, at the latest.
105 struct onstart_flags_t {
106 bool rw_ready : 1; // file system should be writable once this service starts
107 bool log_ready : 1; // syslog should be available once this service starts
109 // Not actually "onstart" commands:
110 bool no_sigterm : 1; // do not send SIGTERM
111 bool runs_on_console : 1; // run "in the foreground"
112 bool starts_on_console : 1; // starts in the foreground
113 bool pass_cs_fd : 1; // pass this service a control socket connection via fd
115 onstart_flags_t() noexcept : rw_ready(false), log_ready(false),
116 no_sigterm(false), runs_on_console(false), starts_on_console(false), pass_cs_fd(false)
121 // Exception while loading a service
122 class service_load_exc
125 std::string serviceName;
126 std::string excDescription;
129 service_load_exc(std::string serviceName, std::string &&desc) noexcept
130 : serviceName(serviceName), excDescription(std::move(desc))
135 class service_not_found : public service_load_exc
138 service_not_found(std::string serviceName) noexcept
139 : service_load_exc(serviceName, "Service description not found.")
144 class service_cyclic_dependency : public service_load_exc
147 service_cyclic_dependency(std::string serviceName) noexcept
148 : service_load_exc(serviceName, "Has cyclic dependency.")
153 class service_description_exc : public service_load_exc
156 service_description_exc(std::string serviceName, std::string &&extraInfo) noexcept
157 : service_load_exc(serviceName, std::move(extraInfo))
162 class service_record;
164 class base_process_service;
166 enum class dependency_type
169 SOFT, // dependency starts in parallel, failure/stop does not affect dependent
170 WAITS_FOR, // as for SOFT, but dependent waits until dependency starts/fails before starting
171 MILESTONE // dependency must start successfully, but once started the dependency becomes soft
174 /* Service dependency record */
177 service_record * from;
181 /* Whether the 'from' service is waiting for the 'to' service to start */
183 /* Whether the 'from' service is holding an acquire on the 'to' service */
186 const dependency_type dep_type;
188 service_dep(service_record * from, service_record * to, dependency_type dep_type_p) noexcept
189 : from(from), to(to), waiting_on(false), holding_acq(false), dep_type(dep_type_p)
192 service_record * get_from() noexcept
197 service_record * get_to() noexcept
203 /* preliminary service dependency information */
207 service_record * const to;
208 dependency_type const dep_type;
210 prelim_dep(service_record *to_p, dependency_type dep_type_p) : to(to_p), dep_type(dep_type_p)
216 // Given a string and a list of pairs of (start,end) indices for each argument in that string,
217 // store a null terminator for the argument. Return a `char *` vector containing the beginning
218 // of each argument and a trailing nullptr. (The returned array is invalidated if the string is later modified).
219 static std::vector<const char *> separate_args(std::string &s, std::list<std::pair<unsigned,unsigned>> &arg_indices)
221 std::vector<const char *> r;
222 r.reserve(arg_indices.size() + 1);
224 // First store nul terminator for each part:
225 for (auto index_pair : arg_indices) {
226 if (index_pair.second < s.length()) {
227 s[index_pair.second] = 0;
231 // Now we can get the C string (c_str) and store offsets into it:
232 const char * cstr = s.c_str();
233 for (auto index_pair : arg_indices) {
234 r.push_back(cstr + index_pair.first);
236 r.push_back(nullptr);
240 class service_child_watcher : public eventloop_t::child_proc_watcher_impl<service_child_watcher>
243 base_process_service * service;
244 rearm status_change(eventloop_t &eloop, pid_t child, int status) noexcept;
246 service_child_watcher(base_process_service * sr) noexcept : service(sr) { }
249 // Watcher for the pipe used to receive exec() failure status errno
250 class exec_status_pipe_watcher : public eventloop_t::fd_watcher_impl<exec_status_pipe_watcher>
253 base_process_service * service;
254 rearm fd_event(eventloop_t &eloop, int fd, int flags) noexcept;
256 exec_status_pipe_watcher(base_process_service * sr) noexcept : service(sr) { }
259 // service_record: base class for service record containing static information
260 // and current state of each service.
262 // This abstract base class defines the dependency behaviour of services. The actions to actually bring a
263 // service up or down are specified by subclasses in the virtual methods (see especially bring_up() and
269 using string = std::string;
273 service_type record_type; /* ServiceType::DUMMY, PROCESS, SCRIPTED, INTERNAL */
274 service_state_t service_state = service_state_t::STOPPED; /* service_state_t::STOPPED, STARTING, STARTED, STOPPING */
275 service_state_t desired_state = service_state_t::STOPPED; /* service_state_t::STOPPED / STARTED */
278 string program_name; // storage for program/script and arguments
279 std::vector<const char *> exec_arg_parts; // pointer to each argument/part of the program_name, and nullptr
281 string stop_command; // storage for stop program/script and arguments
282 std::vector<const char *> stop_arg_parts; // pointer to each argument/part of the stop_command, and nullptr
286 onstart_flags_t onstart_flags;
288 string logfile; // log file name, empty string specifies /dev/null
290 bool auto_restart : 1; // whether to restart this (process) if it dies unexpectedly
291 bool smooth_recovery : 1; // whether the service process can restart without bringing down service
293 bool pinned_stopped : 1;
294 bool pinned_started : 1;
295 bool waiting_for_deps : 1; // if STARTING, whether we are waiting for dependencies (inc console) to start
296 // if STOPPING, whether we are waiting for dependents to stop
297 bool waiting_for_execstat : 1; // if we are waiting for exec status after fork()
298 bool start_explicit : 1; // whether we are are explicitly required to be started
300 bool prop_require : 1; // require must be propagated
301 bool prop_release : 1; // release must be propagated
302 bool prop_failure : 1; // failure to start must be propagated
306 bool restarting : 1; // re-starting after unexpected termination
308 int required_by = 0; // number of dependents wanting this service to be started
310 // list of dependencies
311 typedef std::list<service_dep> dep_list;
313 // list of dependents
314 typedef std::list<service_dep *> dpt_list;
316 dep_list depends_on; // services this one depends on
317 dpt_list dependents; // services depending on this one
319 service_set *services; // the set this service belongs to
321 std::unordered_set<service_listener *> listeners;
324 bool force_stop; // true if the service must actually stop. This is the
325 // case if for example the process dies; the service,
326 // and all its dependencies, MUST be stopped.
328 int term_signal = -1; // signal to use for process termination
330 string socket_path; // path to the socket for socket-activation service
331 int socket_perms; // socket permissions ("mode")
332 uid_t socket_uid = -1; // socket user id or -1
333 gid_t socket_gid = -1; // socket group id or -1
335 // Implementation details
337 pid_t pid = -1; // PID of the process. If state is STARTING or STOPPING,
338 // this is PID of the service script; otherwise it is the
339 // PID of the process itself (process service).
340 int exit_status; // Exit status, if the process has exited (pid == -1).
341 int socket_fd = -1; // For socket-activation services, this is the file
342 // descriptor for the socket.
344 // Data for use by service_set
348 lld_node<service_record> console_queue_node;
350 // Propagation and start/stop queues
351 lls_node<service_record> prop_queue_node;
352 lls_node<service_record> stop_queue_node;
357 void emergency_stop() noexcept;
359 // Service has actually stopped (includes having all dependents
360 // reaching STOPPED state).
361 void stopped() noexcept;
363 // Service has successfully started
364 void started() noexcept;
366 // Service failed to start (only called when in STARTING state).
367 // dep_failed: whether failure is recorded due to a dependency failing
368 void failed_to_start(bool dep_failed = false) noexcept;
370 void run_child_proc(const char * const *args, const char *logfile, bool on_console, int wpipefd,
373 // A dependency has reached STARTED state
374 void dependency_started() noexcept;
376 void all_deps_started(bool haveConsole = false) noexcept;
378 // Open the activation socket, return false on failure
379 bool open_socket() noexcept;
381 // Start all dependencies, return true if all have started
382 bool start_check_dependencies() noexcept;
384 // Check whether all dependencies have started (i.e. whether we can start now)
385 bool check_deps_started() noexcept;
387 // Whether a STOPPING service can immediately transition to STARTED.
388 bool can_interrupt_stop() noexcept
390 return waiting_for_deps && ! force_stop;
393 // A dependent has reached STOPPED state
394 void dependent_stopped() noexcept;
396 // check if all dependents have stopped
397 bool stop_check_dependents() noexcept;
399 // issue a stop to all dependents, return true if they are all already stopped
400 bool stop_dependents() noexcept;
402 void require() noexcept;
403 void release() noexcept;
404 void release_dependencies() noexcept;
406 // Check if service is, fundamentally, stopped.
407 bool is_stopped() noexcept
409 return service_state == service_state_t::STOPPED
410 || (service_state == service_state_t::STARTING && waiting_for_deps);
413 void notify_listeners(service_event_t event) noexcept
415 for (auto l : listeners) {
416 l->service_event(this, event);
420 // Queue to run on the console. 'acquired_console()' will be called when the console is available.
421 // Has no effect if the service has already queued for console.
422 void queue_for_console() noexcept;
424 // Release console (console must be currently held by this service)
425 void release_console() noexcept;
427 bool do_auto_restart() noexcept;
429 // Started state reached
430 bool process_started() noexcept;
432 // Called on transition of desired state from stopped to started (or unpinned stop)
433 void do_start() noexcept;
435 // Called on transition of desired state from started to stopped (or unpinned start)
436 void do_stop() noexcept;
438 // Virtual functions, to be implemented by service implementations:
440 // Do any post-dependency startup; return false on failure
441 virtual bool bring_up() noexcept;
443 // All dependents have stopped, and this service should proceed to stop.
444 virtual void bring_down() noexcept;
446 // Whether a STARTING service can immediately transition to STOPPED (as opposed to
447 // having to wait for it reach STARTED and then go through STOPPING).
448 virtual bool can_interrupt_start() noexcept
450 return waiting_for_deps;
453 // Whether a STARTING service can transition to its STARTED state, once all
454 // dependencies have started.
455 virtual bool can_proceed_to_start() noexcept
460 virtual void interrupt_start() noexcept;
464 service_record(service_set *set, string name)
465 : service_state(service_state_t::STOPPED), desired_state(service_state_t::STOPPED),
466 auto_restart(false), smooth_recovery(false),
467 pinned_stopped(false), pinned_started(false), waiting_for_deps(false),
468 waiting_for_execstat(false), start_explicit(false),
469 prop_require(false), prop_release(false), prop_failure(false),
470 prop_start(false), prop_stop(false), restarting(false), force_stop(false)
474 record_type = service_type::DUMMY;
479 service_record(service_set *set, string name, service_type record_type_p,
480 const std::list<prelim_dep> &deplist_p)
481 : service_record(set, name)
485 this->record_type = record_type_p;
487 for (auto & pdep : deplist_p) {
488 auto b = depends_on.emplace(depends_on.end(), this, pdep.to, pdep.dep_type);
489 pdep.to->dependents.push_back(&(*b));
493 service_record(service_set *set, string name, service_type record_type_p, string &&command,
494 std::list<std::pair<unsigned,unsigned>> &command_offsets,
495 const std::list<prelim_dep> &deplist_p)
496 : service_record(set, name, record_type_p, deplist_p)
498 program_name = std::move(command);
499 exec_arg_parts = separate_args(program_name, command_offsets);
502 virtual ~service_record() noexcept
506 // Get the type of this service record
507 service_type get_type() noexcept
512 // begin transition from stopped to started state or vice versa depending on current and desired state
513 void execute_transition() noexcept;
515 void do_propagation() noexcept;
517 // Console is available.
518 void acquired_console() noexcept;
520 // Set the stop command and arguments (may throw std::bad_alloc)
521 void set_stop_command(std::string command, std::list<std::pair<unsigned,unsigned>> &stop_command_offsets)
523 stop_command = command;
524 stop_arg_parts = separate_args(stop_command, stop_command_offsets);
527 // Get the target (aka desired) state.
528 service_state_t get_target_state() noexcept
530 return desired_state;
533 // Set logfile, should be done before service is started
534 void set_log_file(string logfile)
536 this->logfile = logfile;
539 // Set whether this service should automatically restart when it dies
540 void set_auto_restart(bool auto_restart) noexcept
542 this->auto_restart = auto_restart;
545 void set_smooth_recovery(bool smooth_recovery) noexcept
547 this->smooth_recovery = smooth_recovery;
550 // Set "on start" flags (commands)
551 void set_flags(onstart_flags_t flags) noexcept
553 this->onstart_flags = flags;
556 // Set an additional signal (other than SIGTERM) to be used to terminate the process
557 void set_extra_termination_signal(int signo) noexcept
559 this->term_signal = signo;
562 void set_pid_file(string &&pid_file) noexcept
564 this->pid_file = std::move(pid_file);
567 void set_socket_details(string &&socket_path, int socket_perms, uid_t socket_uid, uid_t socket_gid) noexcept
569 this->socket_path = std::move(socket_path);
570 this->socket_perms = socket_perms;
571 this->socket_uid = socket_uid;
572 this->socket_gid = socket_gid;
575 const std::string &get_name() const noexcept { return service_name; }
576 service_state_t get_state() const noexcept { return service_state; }
578 void start(bool activate = true) noexcept; // start the service
579 void stop(bool bring_down = true) noexcept; // stop the service
581 void forced_stop() noexcept; // force-stop this service and all dependents
583 // Pin the service in "started" state (when it reaches the state)
584 void pin_start() noexcept
586 pinned_started = true;
589 // Pin the service in "stopped" state (when it reaches the state)
590 void pin_stop() noexcept
592 pinned_stopped = true;
595 // Remove both "started" and "stopped" pins. If the service is currently pinned
596 // in either state but would naturally be in the opposite state, it will immediately
597 // commence starting/stopping.
598 void unpin() noexcept;
600 bool isDummy() noexcept
602 return record_type == service_type::DUMMY;
605 // Add a listener. A listener must only be added once. May throw std::bad_alloc.
606 void addListener(service_listener * listener)
608 listeners.insert(listener);
611 // Remove a listener.
612 void removeListener(service_listener * listener) noexcept
614 listeners.erase(listener);
618 class base_process_service;
620 // A timer for process restarting. Used to ensure a minimum delay between process restarts (and
621 // also for timing service stop before the SIGKILL hammer is used).
622 class process_restart_timer : public eventloop_t::timer_impl<process_restart_timer>
625 base_process_service * service;
627 process_restart_timer()
631 rearm timer_expiry(eventloop_t &, int expiry_count);
634 class base_process_service : public service_record
636 friend class service_child_watcher;
637 friend class exec_status_pipe_watcher;
638 friend class process_restart_timer;
642 void do_restart() noexcept;
645 service_child_watcher child_listener;
646 exec_status_pipe_watcher child_status_listener;
647 process_restart_timer restart_timer;
648 time_val last_start_time;
650 // Restart interval time and restart count are used to track the number of automatic restarts
651 // over an interval. Too many restarts over an interval will inhibit further restarts.
652 time_val restart_interval_time;
653 int restart_interval_count;
655 time_val restart_interval;
656 int max_restart_interval_count;
657 time_val restart_delay;
659 // Time allowed for service stop, after which SIGKILL is sent. 0 to disable.
660 time_val stop_timeout = {10, 0}; // default of 10 seconds
662 bool waiting_restart_timer : 1;
663 bool stop_timer_armed : 1;
664 bool reserved_child_watch : 1;
665 bool tracking_child : 1; // whether we expect to see child process status
666 bool start_is_interruptible : 1; // whether we can interrupt start
668 // Start the process, return true on success
669 virtual bool bring_up() noexcept override;
670 bool start_ps_process(const std::vector<const char *> &args, bool on_console) noexcept;
672 // Restart the process (due to start failure or unexpected termination). Restarts will be
674 bool restart_ps_process() noexcept;
676 // Perform smooth recovery process
677 void do_smooth_recovery() noexcept;
679 virtual void bring_down() noexcept override;
681 // Called when the process exits. The exit_status is the status value yielded by
682 // the "wait" system call.
683 virtual void handle_exit_status(int exit_status) noexcept = 0;
684 virtual void exec_failed(int errcode) noexcept = 0;
686 virtual bool can_interrupt_start() noexcept override
688 return waiting_restart_timer || service_record::can_interrupt_start();
691 virtual bool can_proceed_to_start() noexcept override
693 return ! waiting_restart_timer;
696 virtual void interrupt_start() noexcept override;
699 void kill_with_fire() noexcept;
701 // Signal the process group of the service process
702 void kill_pg(int signo) noexcept;
705 base_process_service(service_set *sset, string name, service_type record_type_p, string &&command,
706 std::list<std::pair<unsigned,unsigned>> &command_offsets,
707 const std::list<prelim_dep> &deplist_p);
709 ~base_process_service() noexcept
713 void set_restart_interval(timespec interval, int max_restarts) noexcept
715 restart_interval = interval;
716 max_restart_interval_count = max_restarts;
719 void set_restart_delay(timespec delay) noexcept
721 restart_delay = delay;
724 void set_stop_timeout(timespec timeout) noexcept
726 stop_timeout = timeout;
730 class process_service : public base_process_service
732 virtual void handle_exit_status(int exit_status) noexcept override;
733 virtual void exec_failed(int errcode) noexcept override;
734 virtual void bring_down() noexcept override;
737 process_service(service_set *sset, string name, string &&command,
738 std::list<std::pair<unsigned,unsigned>> &command_offsets,
739 std::list<prelim_dep> depends_p)
740 : base_process_service(sset, name, service_type::PROCESS, std::move(command), command_offsets,
745 ~process_service() noexcept
750 class bgproc_service : public base_process_service
752 virtual void handle_exit_status(int exit_status) noexcept override;
753 virtual void exec_failed(int errcode) noexcept override;
755 enum class pid_result_t {
757 FAILED, // failed to read pid or read invalid pid
758 TERMINATED // read pid successfully, but the process already terminated
761 // Read the pid-file, return false on failure
762 pid_result_t read_pid_file(int *exit_status) noexcept;
765 bgproc_service(service_set *sset, string name, string &&command,
766 std::list<std::pair<unsigned,unsigned>> &command_offsets,
767 std::list<prelim_dep> depends_p)
768 : base_process_service(sset, name, service_type::BGPROCESS, std::move(command), command_offsets,
773 ~bgproc_service() noexcept
778 class scripted_service : public base_process_service
780 virtual void handle_exit_status(int exit_status) noexcept override;
781 virtual void exec_failed(int errcode) noexcept override;
782 virtual void bring_down() noexcept override;
785 scripted_service(service_set *sset, string name, string &&command,
786 std::list<std::pair<unsigned,unsigned>> &command_offsets,
787 std::list<prelim_dep> depends_p)
788 : base_process_service(sset, name, service_type::SCRIPTED, std::move(command), command_offsets,
793 ~scripted_service() noexcept
798 inline auto extract_prop_queue(service_record *sr) -> decltype(sr->prop_queue_node) &
800 return sr->prop_queue_node;
803 inline auto extract_stop_queue(service_record *sr) -> decltype(sr->stop_queue_node) &
805 return sr->stop_queue_node;
808 inline auto extract_console_queue(service_record *sr) -> decltype(sr->console_queue_node) &
810 return sr->console_queue_node;
814 * A service_set, as the name suggests, manages a set of services.
816 * Other than the ability to find services by name, the service set manages various queues.
817 * One is the queue for processes wishing to acquire the console. There is also a set of
818 * processes that want to start, and another set of those that want to stop. These latter
819 * two "queues" (not really queues since their order is not important) are used to prevent too
820 * much recursion and to prevent service states from "bouncing" too rapidly.
822 * A service that wishes to start or stop puts itself on the start/stop queue; a service that
823 * needs to propagate changes to dependent services or dependencies puts itself on the
824 * propagation queue. Any operation that potentially manipulates the queues must be followed
825 * by a "process queues" order (processQueues() method).
827 * Note that processQueues always repeatedly processes both queues until they are empty. The
828 * process is finite because starting a service can never cause services to stop, unless they
829 * fail to start, which should cause them to stop semi-permanently.
835 std::list<service_record *> records;
836 bool restart_enabled; // whether automatic restart is enabled (allowed)
838 shutdown_type_t shutdown_type = shutdown_type_t::CONTINUE; // Shutdown type, if stopping
840 // Services waiting for exclusive access to the console
841 dlist<service_record, extract_console_queue> console_queue;
843 // Propagation and start/stop "queues" - list of services waiting for processing
844 slist<service_record, extract_prop_queue> prop_queue;
845 slist<service_record, extract_stop_queue> stop_queue;
851 restart_enabled = true;
854 virtual ~service_set()
856 for (auto * s : records) {
861 // Start the specified service. The service will be marked active.
862 void start_service(service_record *svc)
868 // Stop the specified service. Its active mark will be cleared.
869 void stop_service(service_record *svc)
875 // Locate an existing service record.
876 service_record *find_service(const std::string &name) noexcept;
878 // Load a service description, and dependencies, if there is no existing
879 // record for the given name.
881 // ServiceLoadException (or subclass) on problem with service description
882 // std::bad_alloc on out-of-memory condition
883 virtual service_record *load_service(const char *name)
885 auto r = find_service(name);
887 throw service_not_found(name);
892 // Start the service with the given name. The named service will begin
893 // transition to the 'started' state.
895 // Throws a ServiceLoadException (or subclass) if the service description
896 // cannot be loaded or is invalid;
897 // Throws std::bad_alloc if out of memory.
898 void start_service(const char *name)
901 service_record *record = load_service(name);
902 service_set::start_service(record);
905 void add_service(service_record *svc)
907 records.push_back(svc);
910 void remove_service(service_record *svc)
912 std::remove(records.begin(), records.end(), svc);
915 // Get the list of all loaded services.
916 const std::list<service_record *> &list_services() noexcept
921 // Stop the service with the given name. The named service will begin
922 // transition to the 'stopped' state.
923 void stop_service(const std::string &name) noexcept;
925 // Add a service record to the state propagation queue. The service record will have its
926 // do_propagation() method called when the queue is processed.
927 void add_prop_queue(service_record *service) noexcept
929 if (! prop_queue.is_queued(service)) {
930 prop_queue.insert(service);
934 // Add a service record to the stop queue. The service record will have its
935 // execute_transition() method called when the queue is processed.
936 void add_transition_queue(service_record *service) noexcept
938 if (! stop_queue.is_queued(service)) {
939 stop_queue.insert(service);
943 // Process state propagation and start/stop queues, until they are empty.
944 void process_queues() noexcept
946 while (! stop_queue.is_empty() || ! prop_queue.is_empty()) {
947 while (! prop_queue.is_empty()) {
948 auto next = prop_queue.pop_front();
949 next->do_propagation();
951 while (! stop_queue.is_empty()) {
952 auto next = stop_queue.pop_front();
953 next->execute_transition();
958 // Set the console queue tail (returns previous tail)
959 void append_console_queue(service_record * newTail) noexcept
961 bool was_empty = console_queue.is_empty();
962 console_queue.append(newTail);
964 enable_console_log(false);
968 // Pull and dispatch a waiter from the console queue
969 void pull_console_queue() noexcept
971 if (console_queue.is_empty()) {
972 enable_console_log(true);
975 service_record * front = console_queue.pop_front();
976 front->acquired_console();
980 void unqueue_console(service_record * service) noexcept
982 if (console_queue.is_queued(service)) {
983 console_queue.unlink(service);
987 // Notification from service that it is active (state != STOPPED)
988 // Only to be called on the transition from inactive to active.
989 void service_active(service_record *) noexcept;
991 // Notification from service that it is inactive (STOPPED)
992 // Only to be called on the transition from active to inactive.
993 void service_inactive(service_record *) noexcept;
995 // Find out how many services are active (starting, running or stopping,
997 int count_active_services() noexcept
999 return active_services;
1002 void stop_all_services(shutdown_type_t type = shutdown_type_t::HALT) noexcept
1004 restart_enabled = false;
1005 shutdown_type = type;
1006 for (std::list<service_record *>::iterator i = records.begin(); i != records.end(); ++i) {
1013 void set_auto_restart(bool restart) noexcept
1015 restart_enabled = restart;
1018 bool get_auto_restart() noexcept
1020 return restart_enabled;
1023 shutdown_type_t getShutdownType() noexcept
1025 return shutdown_type;
1029 class dirload_service_set : public service_set
1031 const char *service_dir; // directory containing service descriptions
1034 dirload_service_set(const char *service_dir_p) : service_set(), service_dir(service_dir_p)
1038 service_record *load_service(const char *name) override;