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.
264 typedef std::string string;
267 service_type record_type; /* ServiceType::DUMMY, PROCESS, SCRIPTED, INTERNAL */
268 service_state_t service_state = service_state_t::STOPPED; /* service_state_t::STOPPED, STARTING, STARTED, STOPPING */
269 service_state_t desired_state = service_state_t::STOPPED; /* service_state_t::STOPPED / STARTED */
271 string program_name; // storage for program/script and arguments
272 std::vector<const char *> exec_arg_parts; // pointer to each argument/part of the program_name, and nullptr
274 string stop_command; // storage for stop program/script and arguments
275 std::vector<const char *> stop_arg_parts; // pointer to each argument/part of the stop_command, and nullptr
279 onstart_flags_t onstart_flags;
281 string logfile; // log file name, empty string specifies /dev/null
283 bool auto_restart : 1; // whether to restart this (process) if it dies unexpectedly
284 bool smooth_recovery : 1; // whether the service process can restart without bringing down service
286 bool pinned_stopped : 1;
287 bool pinned_started : 1;
288 bool waiting_for_deps : 1; // if STARTING, whether we are waiting for dependencies (inc console) to start
289 // if STOPPING, whether we are waiting for dependents to stop
290 bool waiting_for_execstat : 1; // if we are waiting for exec status after fork()
291 bool start_explicit : 1; // whether we are are explicitly required to be started
293 bool prop_require : 1; // require must be propagated
294 bool prop_release : 1; // release must be propagated
295 bool prop_failure : 1; // failure to start must be propagated
299 bool restarting : 1; // re-starting after unexpected termination
301 int required_by = 0; // number of dependents wanting this service to be started
303 // list of dependencies
304 typedef std::list<service_dep> dep_list;
306 // list of dependents
307 typedef std::list<service_dep *> dpt_list;
309 dep_list depends_on; // services this one depends on
310 dpt_list dependents; // services depending on this one
312 service_set *services; // the set this service belongs to
314 std::unordered_set<service_listener *> listeners;
317 bool force_stop; // true if the service must actually stop. This is the
318 // case if for example the process dies; the service,
319 // and all its dependencies, MUST be stopped.
321 int term_signal = -1; // signal to use for process termination
323 string socket_path; // path to the socket for socket-activation service
324 int socket_perms; // socket permissions ("mode")
325 uid_t socket_uid = -1; // socket user id or -1
326 gid_t socket_gid = -1; // socket group id or -1
328 // Implementation details
330 pid_t pid = -1; // PID of the process. If state is STARTING or STOPPING,
331 // this is PID of the service script; otherwise it is the
332 // PID of the process itself (process service).
333 int exit_status; // Exit status, if the process has exited (pid == -1).
334 int socket_fd = -1; // For socket-activation services, this is the file
335 // descriptor for the socket.
337 // Data for use by service_set
341 lld_node<service_record> console_queue_node;
343 // Propagation and start/stop queues
344 lls_node<service_record> prop_queue_node;
345 lls_node<service_record> stop_queue_node;
350 void emergency_stop() noexcept;
352 // All dependents have stopped, and this service should proceed to stop.
353 virtual void bring_down() noexcept;
355 // Service has actually stopped (includes having all dependents
356 // reaching STOPPED state).
357 void stopped() noexcept;
359 // Service has successfully started
360 void started() noexcept;
362 // Service failed to start (only called when in STARTING state).
363 // dep_failed: whether failure is recorded due to a dependency failing
364 void failed_to_start(bool dep_failed = false) noexcept;
366 void run_child_proc(const char * const *args, const char *logfile, bool on_console, int wpipefd,
369 // A dependency has reached STARTED state
370 void dependency_started() noexcept;
372 void all_deps_started(bool haveConsole = false) noexcept;
374 // Do any post-dependency startup; return false on failure
375 virtual bool start_ps_process() noexcept;
377 // Open the activation socket, return false on failure
378 bool open_socket() noexcept;
380 // Start all dependencies, return true if all have started
381 bool start_check_dependencies() noexcept;
383 // Check whether all dependencies have started (i.e. whether we can start now)
384 bool check_deps_started() noexcept;
386 // Whether a STARTING service can immediately transition to STOPPED (as opposed to
387 // having to wait for it reach STARTED and then go through STOPPING).
388 virtual bool can_interrupt_start() noexcept
390 return waiting_for_deps;
393 // Whether a STARTING service can transition to its STARTED state, once all
394 // dependencies have started.
395 virtual bool can_proceed_to_start() noexcept
400 virtual void interrupt_start() noexcept;
402 // Whether a STOPPING service can immediately transition to STARTED.
403 bool can_interrupt_stop() noexcept
405 return waiting_for_deps && ! force_stop;
408 // A dependent has reached STOPPED state
409 void dependent_stopped() noexcept;
411 // check if all dependents have stopped
412 bool stop_check_dependents() noexcept;
414 // issue a stop to all dependents, return true if they are all already stopped
415 bool stop_dependents() noexcept;
417 void require() noexcept;
418 void release() noexcept;
419 void release_dependencies() noexcept;
421 // Check if service is, fundamentally, stopped.
422 bool is_stopped() noexcept
424 return service_state == service_state_t::STOPPED
425 || (service_state == service_state_t::STARTING && waiting_for_deps);
428 void notify_listeners(service_event_t event) noexcept
430 for (auto l : listeners) {
431 l->service_event(this, event);
435 // Queue to run on the console. 'acquired_console()' will be called when the console is available.
436 // Has no effect if the service has already queued for console.
437 void queue_for_console() noexcept;
439 // Release console (console must be currently held by this service)
440 void release_console() noexcept;
442 bool do_auto_restart() noexcept;
444 // Started state reached
445 bool process_started() noexcept;
447 // Called on transition of desired state from stopped to started (or unpinned stop)
448 void do_start() noexcept;
450 // Called on transition of desired state from started to stopped (or unpinned start)
451 void do_stop() noexcept;
455 service_record(service_set *set, string name)
456 : service_state(service_state_t::STOPPED), desired_state(service_state_t::STOPPED),
457 auto_restart(false), smooth_recovery(false),
458 pinned_stopped(false), pinned_started(false), waiting_for_deps(false),
459 waiting_for_execstat(false), start_explicit(false),
460 prop_require(false), prop_release(false), prop_failure(false),
461 prop_start(false), prop_stop(false), restarting(false), force_stop(false)
465 record_type = service_type::DUMMY;
470 service_record(service_set *set, string name, service_type record_type_p,
471 const std::list<prelim_dep> &deplist_p)
472 : service_record(set, name)
476 this->record_type = record_type_p;
478 for (auto & pdep : deplist_p) {
479 auto b = depends_on.emplace(depends_on.end(), this, pdep.to, pdep.dep_type);
480 pdep.to->dependents.push_back(&(*b));
484 service_record(service_set *set, string name, service_type record_type_p, string &&command,
485 std::list<std::pair<unsigned,unsigned>> &command_offsets,
486 const std::list<prelim_dep> &deplist_p)
487 : service_record(set, name, record_type_p, deplist_p)
489 program_name = std::move(command);
490 exec_arg_parts = separate_args(program_name, command_offsets);
493 virtual ~service_record() noexcept
497 // begin transition from stopped to started state or vice versa depending on current and desired state
498 void execute_transition() noexcept;
500 void do_propagation() noexcept;
502 // Console is available.
503 void acquired_console() noexcept;
505 // Set the stop command and arguments (may throw std::bad_alloc)
506 void set_stop_command(std::string command, std::list<std::pair<unsigned,unsigned>> &stop_command_offsets)
508 stop_command = command;
509 stop_arg_parts = separate_args(stop_command, stop_command_offsets);
512 // Get the target (aka desired) state.
513 service_state_t get_target_state() noexcept
515 return desired_state;
518 // Set logfile, should be done before service is started
519 void set_log_file(string logfile)
521 this->logfile = logfile;
524 // Set whether this service should automatically restart when it dies
525 void set_auto_restart(bool auto_restart) noexcept
527 this->auto_restart = auto_restart;
530 void set_smooth_recovery(bool smooth_recovery) noexcept
532 this->smooth_recovery = smooth_recovery;
535 // Set "on start" flags (commands)
536 void set_flags(onstart_flags_t flags) noexcept
538 this->onstart_flags = flags;
541 // Set an additional signal (other than SIGTERM) to be used to terminate the process
542 void set_extra_termination_signal(int signo) noexcept
544 this->term_signal = signo;
547 void set_pid_file(string &&pid_file) noexcept
549 this->pid_file = std::move(pid_file);
552 void set_socket_details(string &&socket_path, int socket_perms, uid_t socket_uid, uid_t socket_gid) noexcept
554 this->socket_path = std::move(socket_path);
555 this->socket_perms = socket_perms;
556 this->socket_uid = socket_uid;
557 this->socket_gid = socket_gid;
560 const std::string &get_service_name() const noexcept { return service_name; }
561 service_state_t get_state() const noexcept { return service_state; }
563 void start(bool activate = true) noexcept; // start the service
564 void stop(bool bring_down = true) noexcept; // stop the service
566 void forced_stop() noexcept; // force-stop this service and all dependents
568 // Pin the service in "started" state (when it reaches the state)
569 void pin_start() noexcept
571 pinned_started = true;
574 // Pin the service in "stopped" state (when it reaches the state)
575 void pin_stop() noexcept
577 pinned_stopped = true;
580 // Remove both "started" and "stopped" pins. If the service is currently pinned
581 // in either state but would naturally be in the opposite state, it will immediately
582 // commence starting/stopping.
583 void unpin() noexcept;
585 bool isDummy() noexcept
587 return record_type == service_type::DUMMY;
590 // Add a listener. A listener must only be added once. May throw std::bad_alloc.
591 void addListener(service_listener * listener)
593 listeners.insert(listener);
596 // Remove a listener.
597 void removeListener(service_listener * listener) noexcept
599 listeners.erase(listener);
603 class base_process_service;
605 // A timer for process restarting. Used to ensure a minimum delay between process restarts (and
606 // also for timing service stop before the SIGKILL hammer is used).
607 class process_restart_timer : public eventloop_t::timer_impl<process_restart_timer>
610 base_process_service * service;
612 process_restart_timer()
616 rearm timer_expiry(eventloop_t &, int expiry_count);
619 class base_process_service : public service_record
621 friend class service_child_watcher;
622 friend class exec_status_pipe_watcher;
623 friend class process_restart_timer;
627 void do_restart() noexcept;
630 service_child_watcher child_listener;
631 exec_status_pipe_watcher child_status_listener;
632 process_restart_timer restart_timer;
633 time_val last_start_time;
635 // Restart interval time and restart count are used to track the number of automatic restarts
636 // over an interval. Too many restarts over an interval will inhibit further restarts.
637 time_val restart_interval_time;
638 int restart_interval_count;
640 time_val restart_interval;
641 int max_restart_interval_count;
642 time_val restart_delay;
644 // Time allowed for service stop, after which SIGKILL is sent. 0 to disable.
645 time_val stop_timeout = {10, 0}; // default of 10 seconds
647 bool waiting_restart_timer : 1;
648 bool stop_timer_armed : 1;
649 bool reserved_child_watch : 1;
650 bool tracking_child : 1; // whether we expect to see child process status
651 bool start_is_interruptible : 1; // whether we can interrupt start
653 // Start the process, return true on success
654 virtual bool start_ps_process() noexcept override;
655 bool start_ps_process(const std::vector<const char *> &args, bool on_console) noexcept;
657 // Restart the process (due to start failure or unexpected termination). Restarts will be
659 bool restart_ps_process() noexcept;
661 // Perform smooth recovery process
662 void do_smooth_recovery() noexcept;
664 virtual void bring_down() noexcept override;
666 // Called when the process exits. The exit_status is the status value yielded by
667 // the "wait" system call.
668 virtual void handle_exit_status(int exit_status) noexcept = 0;
669 virtual void exec_failed(int errcode) noexcept = 0;
671 virtual bool can_interrupt_start() noexcept override
673 return waiting_restart_timer || service_record::can_interrupt_start();
676 virtual bool can_proceed_to_start() noexcept override
678 return ! waiting_restart_timer;
681 virtual void interrupt_start() noexcept override;
684 void kill_with_fire() noexcept;
686 // Signal the process group of the service process
687 void kill_pg(int signo) noexcept;
690 base_process_service(service_set *sset, string name, service_type record_type_p, string &&command,
691 std::list<std::pair<unsigned,unsigned>> &command_offsets,
692 const std::list<prelim_dep> &deplist_p);
694 ~base_process_service() noexcept
698 void set_restart_interval(timespec interval, int max_restarts) noexcept
700 restart_interval = interval;
701 max_restart_interval_count = max_restarts;
704 void set_restart_delay(timespec delay) noexcept
706 restart_delay = delay;
709 void set_stop_timeout(timespec timeout) noexcept
711 stop_timeout = timeout;
715 class process_service : public base_process_service
717 virtual void handle_exit_status(int exit_status) noexcept override;
718 virtual void exec_failed(int errcode) noexcept override;
719 virtual void bring_down() noexcept override;
722 process_service(service_set *sset, string name, string &&command,
723 std::list<std::pair<unsigned,unsigned>> &command_offsets,
724 std::list<prelim_dep> depends_p)
725 : base_process_service(sset, name, service_type::PROCESS, std::move(command), command_offsets,
730 ~process_service() noexcept
735 class bgproc_service : public base_process_service
737 virtual void handle_exit_status(int exit_status) noexcept override;
738 virtual void exec_failed(int errcode) noexcept override;
740 enum class pid_result_t {
742 FAILED, // failed to read pid or read invalid pid
743 TERMINATED // read pid successfully, but the process already terminated
746 // Read the pid-file, return false on failure
747 pid_result_t read_pid_file(int *exit_status) noexcept;
750 bgproc_service(service_set *sset, string name, string &&command,
751 std::list<std::pair<unsigned,unsigned>> &command_offsets,
752 std::list<prelim_dep> depends_p)
753 : base_process_service(sset, name, service_type::BGPROCESS, std::move(command), command_offsets,
758 ~bgproc_service() noexcept
763 class scripted_service : public base_process_service
765 virtual void handle_exit_status(int exit_status) noexcept override;
766 virtual void exec_failed(int errcode) noexcept override;
767 virtual void bring_down() noexcept override;
770 scripted_service(service_set *sset, string name, string &&command,
771 std::list<std::pair<unsigned,unsigned>> &command_offsets,
772 std::list<prelim_dep> depends_p)
773 : base_process_service(sset, name, service_type::SCRIPTED, std::move(command), command_offsets,
778 ~scripted_service() noexcept
783 inline auto extract_prop_queue(service_record *sr) -> decltype(sr->prop_queue_node) &
785 return sr->prop_queue_node;
788 inline auto extract_stop_queue(service_record *sr) -> decltype(sr->stop_queue_node) &
790 return sr->stop_queue_node;
793 inline auto extract_console_queue(service_record *sr) -> decltype(sr->console_queue_node) &
795 return sr->console_queue_node;
799 * A service_set, as the name suggests, manages a set of services.
801 * Other than the ability to find services by name, the service set manages various queues.
802 * One is the queue for processes wishing to acquire the console. There is also a set of
803 * processes that want to start, and another set of those that want to stop. These latter
804 * two "queues" (not really queues since their order is not important) are used to prevent too
805 * much recursion and to prevent service states from "bouncing" too rapidly.
807 * A service that wishes to start or stop puts itself on the start/stop queue; a service that
808 * needs to propagate changes to dependent services or dependencies puts itself on the
809 * propagation queue. Any operation that potentially manipulates the queues must be followed
810 * by a "process queues" order (processQueues() method).
812 * Note that processQueues always repeatedly processes both queues until they are empty. The
813 * process is finite because starting a service can never cause services to stop, unless they
814 * fail to start, which should cause them to stop semi-permanently.
820 std::list<service_record *> records;
821 bool restart_enabled; // whether automatic restart is enabled (allowed)
823 shutdown_type_t shutdown_type = shutdown_type_t::CONTINUE; // Shutdown type, if stopping
825 // Services waiting for exclusive access to the console
826 dlist<service_record, extract_console_queue> console_queue;
828 // Propagation and start/stop "queues" - list of services waiting for processing
829 slist<service_record, extract_prop_queue> prop_queue;
830 slist<service_record, extract_stop_queue> stop_queue;
836 restart_enabled = true;
839 virtual ~service_set()
841 for (auto * s : records) {
846 // Start the specified service. The service will be marked active.
847 void start_service(service_record *svc)
853 // Stop the specified service. Its active mark will be cleared.
854 void stop_service(service_record *svc)
860 // Locate an existing service record.
861 service_record *find_service(const std::string &name) noexcept;
863 // Load a service description, and dependencies, if there is no existing
864 // record for the given name.
866 // ServiceLoadException (or subclass) on problem with service description
867 // std::bad_alloc on out-of-memory condition
868 virtual service_record *load_service(const char *name)
870 auto r = find_service(name);
872 throw service_not_found(name);
877 // Start the service with the given name. The named service will begin
878 // transition to the 'started' state.
880 // Throws a ServiceLoadException (or subclass) if the service description
881 // cannot be loaded or is invalid;
882 // Throws std::bad_alloc if out of memory.
883 void start_service(const char *name)
886 service_record *record = load_service(name);
887 service_set::start_service(record);
890 void add_service(service_record *svc)
892 records.push_back(svc);
895 void remove_service(service_record *svc)
897 std::remove(records.begin(), records.end(), svc);
900 // Get the list of all loaded services.
901 const std::list<service_record *> &list_services() noexcept
906 // Stop the service with the given name. The named service will begin
907 // transition to the 'stopped' state.
908 void stop_service(const std::string &name) noexcept;
910 // Add a service record to the state propagation queue. The service record will have its
911 // do_propagation() method called when the queue is processed.
912 void add_prop_queue(service_record *service) noexcept
914 if (! prop_queue.is_queued(service)) {
915 prop_queue.insert(service);
919 // Add a service record to the stop queue. The service record will have its
920 // execute_transition() method called when the queue is processed.
921 void add_transition_queue(service_record *service) noexcept
923 if (! stop_queue.is_queued(service)) {
924 stop_queue.insert(service);
928 // Process state propagation and start/stop queues, until they are empty.
929 void process_queues() noexcept
931 while (! stop_queue.is_empty() || ! prop_queue.is_empty()) {
932 while (! prop_queue.is_empty()) {
933 auto next = prop_queue.pop_front();
934 next->do_propagation();
936 while (! stop_queue.is_empty()) {
937 auto next = stop_queue.pop_front();
938 next->execute_transition();
943 // Set the console queue tail (returns previous tail)
944 void append_console_queue(service_record * newTail) noexcept
946 bool was_empty = console_queue.is_empty();
947 console_queue.append(newTail);
949 enable_console_log(false);
953 // Pull and dispatch a waiter from the console queue
954 void pull_console_queue() noexcept
956 if (console_queue.is_empty()) {
957 enable_console_log(true);
960 service_record * front = console_queue.pop_front();
961 front->acquired_console();
965 void unqueue_console(service_record * service) noexcept
967 if (console_queue.is_queued(service)) {
968 console_queue.unlink(service);
972 // Notification from service that it is active (state != STOPPED)
973 // Only to be called on the transition from inactive to active.
974 void service_active(service_record *) noexcept;
976 // Notification from service that it is inactive (STOPPED)
977 // Only to be called on the transition from active to inactive.
978 void service_inactive(service_record *) noexcept;
980 // Find out how many services are active (starting, running or stopping,
982 int count_active_services() noexcept
984 return active_services;
987 void stop_all_services(shutdown_type_t type = shutdown_type_t::HALT) noexcept
989 restart_enabled = false;
990 shutdown_type = type;
991 for (std::list<service_record *>::iterator i = records.begin(); i != records.end(); ++i) {
998 void set_auto_restart(bool restart) noexcept
1000 restart_enabled = restart;
1003 bool get_auto_restart() noexcept
1005 return restart_enabled;
1008 shutdown_type_t getShutdownType() noexcept
1010 return shutdown_type;
1014 class dirload_service_set : public service_set
1016 const char *service_dir; // directory containing service descriptions
1019 dirload_service_set(const char *service_dir_p) : service_set(), service_dir(service_dir_p)
1023 service_record *load_service(const char *name) override;