4 * Copyright (c) 2003-2004 Fabrice Bellard
6 * Permission is hereby granted, free of charge, to any person obtaining a copy
7 * of this software and associated documentation files (the "Software"), to deal
8 * in the Software without restriction, including without limitation the rights
9 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
10 * copies of the Software, and to permit persons to whom the Software is
11 * furnished to do so, subject to the following conditions:
13 * The above copyright notice and this permission notice shall be included in
14 * all copies or substantial portions of the Software.
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
25 #include "qemu/osdep.h"
26 #include "monitor-internal.h"
27 #include "qapi/error.h"
28 #include "qapi/opts-visitor.h"
29 #include "qapi/qapi-emit-events.h"
30 #include "qapi/qapi-visit-control.h"
31 #include "qapi/qmp/qdict.h"
32 #include "qemu/error-report.h"
33 #include "qemu/option.h"
34 #include "sysemu/qtest.h"
38 * To prevent flooding clients, events can be throttled. The
39 * throttling is calculated globally, rather than per-Monitor
42 typedef struct MonitorQAPIEventState {
43 QAPIEvent event; /* Throttling state for this event type and... */
44 QDict *data; /* ... data, see qapi_event_throttle_equal() */
45 QEMUTimer *timer; /* Timer for handling delayed events */
46 QDict *qdict; /* Delayed event (if any) */
47 } MonitorQAPIEventState;
50 int64_t rate; /* Minimum time (in ns) between two events */
51 } MonitorQAPIEventConf;
53 /* Shared monitor I/O thread */
54 IOThread *mon_iothread;
56 /* Coroutine to dispatch the requests received from I/O thread */
57 Coroutine *qmp_dispatcher_co;
60 * Set to true when the dispatcher coroutine should terminate. Protected
63 bool qmp_dispatcher_co_shutdown;
66 * Protects mon_list, monitor_qapi_event_state, coroutine_mon,
69 QemuMutex monitor_lock;
70 static GHashTable *monitor_qapi_event_state;
71 static GHashTable *coroutine_mon; /* Maps Coroutine* to Monitor* */
75 static bool monitor_destroyed;
77 Monitor *monitor_cur(void)
81 qemu_mutex_lock(&monitor_lock);
82 mon = g_hash_table_lookup(coroutine_mon, qemu_coroutine_self());
83 qemu_mutex_unlock(&monitor_lock);
89 * Sets a new current monitor and returns the old one.
91 * If a non-NULL monitor is set for a coroutine, another call
92 * resetting it to NULL is required before the coroutine terminates,
93 * otherwise a stale entry would remain in the hash table.
95 Monitor *monitor_set_cur(Coroutine *co, Monitor *mon)
97 Monitor *old_monitor = monitor_cur();
99 qemu_mutex_lock(&monitor_lock);
101 g_hash_table_replace(coroutine_mon, co, mon);
103 g_hash_table_remove(coroutine_mon, co);
105 qemu_mutex_unlock(&monitor_lock);
111 * Is the current monitor, if any, a QMP monitor?
113 bool monitor_cur_is_qmp(void)
115 Monitor *cur_mon = monitor_cur();
117 return cur_mon && monitor_is_qmp(cur_mon);
121 * Is @mon is using readline?
122 * Note: not all HMP monitors use readline, e.g., gdbserver has a
123 * non-interactive HMP monitor, so readline is not used there.
125 static inline bool monitor_uses_readline(const MonitorHMP *mon)
127 return mon->use_readline;
130 static inline bool monitor_is_hmp_non_interactive(const Monitor *mon)
132 if (monitor_is_qmp(mon)) {
136 return !monitor_uses_readline(container_of(mon, MonitorHMP, common));
139 static gboolean monitor_unblocked(void *do_not_use, GIOCondition cond,
142 Monitor *mon = opaque;
144 QEMU_LOCK_GUARD(&mon->mon_lock);
146 monitor_flush_locked(mon);
147 return G_SOURCE_REMOVE;
150 /* Caller must hold mon->mon_lock */
151 void monitor_flush_locked(Monitor *mon)
157 if (mon->skip_flush) {
161 buf = mon->outbuf->str;
162 len = mon->outbuf->len;
164 if (len && !mon->mux_out) {
165 rc = qemu_chr_fe_write(&mon->chr, (const uint8_t *) buf, len);
166 if ((rc < 0 && errno != EAGAIN) || (rc == len)) {
167 /* all flushed or error */
168 g_string_truncate(mon->outbuf, 0);
173 g_string_erase(mon->outbuf, 0, rc);
175 if (mon->out_watch == 0) {
177 qemu_chr_fe_add_watch(&mon->chr, G_IO_OUT | G_IO_HUP,
178 monitor_unblocked, mon);
183 void monitor_flush(Monitor *mon)
185 QEMU_LOCK_GUARD(&mon->mon_lock);
186 monitor_flush_locked(mon);
189 /* flush at every end of line */
190 int monitor_puts_locked(Monitor *mon, const char *str)
195 for (i = 0; str[i]; i++) {
198 g_string_append_c(mon->outbuf, '\r');
200 g_string_append_c(mon->outbuf, c);
202 monitor_flush_locked(mon);
209 int monitor_puts(Monitor *mon, const char *str)
211 QEMU_LOCK_GUARD(&mon->mon_lock);
212 return monitor_puts_locked(mon, str);
215 int monitor_vprintf(Monitor *mon, const char *fmt, va_list ap)
224 if (monitor_is_qmp(mon)) {
228 buf = g_strdup_vprintf(fmt, ap);
229 n = monitor_puts(mon, buf);
234 int monitor_printf(Monitor *mon, const char *fmt, ...)
240 ret = monitor_vprintf(mon, fmt, ap);
245 void monitor_printc(Monitor *mon, int c)
247 monitor_printf(mon, "'");
250 monitor_printf(mon, "\\'");
253 monitor_printf(mon, "\\\\");
256 monitor_printf(mon, "\\n");
259 monitor_printf(mon, "\\r");
262 if (c >= 32 && c <= 126) {
263 monitor_printf(mon, "%c", c);
265 monitor_printf(mon, "\\x%02x", c);
269 monitor_printf(mon, "'");
273 * Print to current monitor if we have one, else to stderr.
275 int error_vprintf(const char *fmt, va_list ap)
277 Monitor *cur_mon = monitor_cur();
279 if (cur_mon && !monitor_cur_is_qmp()) {
280 return monitor_vprintf(cur_mon, fmt, ap);
282 return vfprintf(stderr, fmt, ap);
285 int error_vprintf_unless_qmp(const char *fmt, va_list ap)
287 Monitor *cur_mon = monitor_cur();
290 return vfprintf(stderr, fmt, ap);
292 if (!monitor_cur_is_qmp()) {
293 return monitor_vprintf(cur_mon, fmt, ap);
298 int error_printf_unless_qmp(const char *fmt, ...)
304 ret = error_vprintf_unless_qmp(fmt, ap);
309 static MonitorQAPIEventConf monitor_qapi_event_conf[QAPI_EVENT__MAX] = {
310 /* Limit guest-triggerable events to 1 per second */
311 [QAPI_EVENT_RTC_CHANGE] = { 1000 * SCALE_MS },
312 [QAPI_EVENT_WATCHDOG] = { 1000 * SCALE_MS },
313 [QAPI_EVENT_BALLOON_CHANGE] = { 1000 * SCALE_MS },
314 [QAPI_EVENT_QUORUM_REPORT_BAD] = { 1000 * SCALE_MS },
315 [QAPI_EVENT_QUORUM_FAILURE] = { 1000 * SCALE_MS },
316 [QAPI_EVENT_VSERPORT_CHANGE] = { 1000 * SCALE_MS },
317 [QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE] = { 1000 * SCALE_MS },
318 [QAPI_EVENT_HV_BALLOON_STATUS_REPORT] = { 1000 * SCALE_MS },
322 * Return the clock to use for recording an event's time.
323 * It's QEMU_CLOCK_REALTIME, except for qtests it's
324 * QEMU_CLOCK_VIRTUAL, to support testing rate limits.
325 * Beware: result is invalid before configure_accelerator().
327 static inline QEMUClockType monitor_get_event_clock(void)
329 return qtest_enabled() ? QEMU_CLOCK_VIRTUAL : QEMU_CLOCK_REALTIME;
333 * Broadcast an event to all monitors.
334 * @qdict is the event object. Its member "event" must match @event.
335 * Caller must hold monitor_lock.
337 static void monitor_qapi_event_emit(QAPIEvent event, QDict *qdict)
342 trace_monitor_protocol_event_emit(event, qdict);
343 QTAILQ_FOREACH(mon, &mon_list, entry) {
344 if (!monitor_is_qmp(mon)) {
348 qmp_mon = container_of(mon, MonitorQMP, common);
349 if (qmp_mon->commands != &qmp_cap_negotiation_commands) {
350 qmp_send_response(qmp_mon, qdict);
355 static void monitor_qapi_event_handler(void *opaque);
358 * Queue a new event for emission to Monitor instances,
359 * applying any rate limiting if required.
362 monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict)
364 MonitorQAPIEventConf *evconf;
365 MonitorQAPIEventState *evstate;
367 assert(event < QAPI_EVENT__MAX);
368 evconf = &monitor_qapi_event_conf[event];
369 trace_monitor_protocol_event_queue(event, qdict, evconf->rate);
371 QEMU_LOCK_GUARD(&monitor_lock);
374 /* Unthrottled event */
375 monitor_qapi_event_emit(event, qdict);
377 QDict *data = qobject_to(QDict, qdict_get(qdict, "data"));
378 MonitorQAPIEventState key = { .event = event, .data = data };
380 evstate = g_hash_table_lookup(monitor_qapi_event_state, &key);
381 assert(!evstate || timer_pending(evstate->timer));
385 * Timer is pending for (at least) evconf->rate ns after
386 * last send. Store event for sending when timer fires,
387 * replacing a prior stored event if any.
389 qobject_unref(evstate->qdict);
390 evstate->qdict = qobject_ref(qdict);
393 * Last send was (at least) evconf->rate ns ago.
394 * Send immediately, and arm the timer to call
395 * monitor_qapi_event_handler() in evconf->rate ns. Any
396 * events arriving before then will be delayed until then.
398 int64_t now = qemu_clock_get_ns(monitor_get_event_clock());
400 monitor_qapi_event_emit(event, qdict);
402 evstate = g_new(MonitorQAPIEventState, 1);
403 evstate->event = event;
404 evstate->data = qobject_ref(data);
405 evstate->qdict = NULL;
406 evstate->timer = timer_new_ns(monitor_get_event_clock(),
407 monitor_qapi_event_handler,
409 g_hash_table_add(monitor_qapi_event_state, evstate);
410 timer_mod_ns(evstate->timer, now + evconf->rate);
415 void qapi_event_emit(QAPIEvent event, QDict *qdict)
418 * monitor_qapi_event_queue_no_reenter() is not reentrant: it
419 * would deadlock on monitor_lock. Work around by queueing
420 * events in thread-local storage.
421 * TODO: remove this, make it re-enter safe.
423 typedef struct MonitorQapiEvent {
426 QSIMPLEQ_ENTRY(MonitorQapiEvent) entry;
428 static __thread QSIMPLEQ_HEAD(, MonitorQapiEvent) event_queue;
429 static __thread bool reentered;
430 MonitorQapiEvent *ev;
433 QSIMPLEQ_INIT(&event_queue);
436 ev = g_new(MonitorQapiEvent, 1);
437 ev->qdict = qobject_ref(qdict);
439 QSIMPLEQ_INSERT_TAIL(&event_queue, ev, entry);
446 while ((ev = QSIMPLEQ_FIRST(&event_queue)) != NULL) {
447 QSIMPLEQ_REMOVE_HEAD(&event_queue, entry);
448 monitor_qapi_event_queue_no_reenter(ev->event, ev->qdict);
449 qobject_unref(ev->qdict);
457 * This function runs evconf->rate ns after sending a throttled
459 * If another event has since been stored, send it.
461 static void monitor_qapi_event_handler(void *opaque)
463 MonitorQAPIEventState *evstate = opaque;
464 MonitorQAPIEventConf *evconf = &monitor_qapi_event_conf[evstate->event];
466 trace_monitor_protocol_event_handler(evstate->event, evstate->qdict);
467 QEMU_LOCK_GUARD(&monitor_lock);
469 if (evstate->qdict) {
470 int64_t now = qemu_clock_get_ns(monitor_get_event_clock());
472 monitor_qapi_event_emit(evstate->event, evstate->qdict);
473 qobject_unref(evstate->qdict);
474 evstate->qdict = NULL;
475 timer_mod_ns(evstate->timer, now + evconf->rate);
477 g_hash_table_remove(monitor_qapi_event_state, evstate);
478 qobject_unref(evstate->data);
479 timer_free(evstate->timer);
484 static unsigned int qapi_event_throttle_hash(const void *key)
486 const MonitorQAPIEventState *evstate = key;
487 unsigned int hash = evstate->event * 255;
489 if (evstate->event == QAPI_EVENT_VSERPORT_CHANGE) {
490 hash += g_str_hash(qdict_get_str(evstate->data, "id"));
493 if (evstate->event == QAPI_EVENT_QUORUM_REPORT_BAD) {
494 hash += g_str_hash(qdict_get_str(evstate->data, "node-name"));
497 if (evstate->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) {
498 hash += g_str_hash(qdict_get_str(evstate->data, "qom-path"));
504 static gboolean qapi_event_throttle_equal(const void *a, const void *b)
506 const MonitorQAPIEventState *eva = a;
507 const MonitorQAPIEventState *evb = b;
509 if (eva->event != evb->event) {
513 if (eva->event == QAPI_EVENT_VSERPORT_CHANGE) {
514 return !strcmp(qdict_get_str(eva->data, "id"),
515 qdict_get_str(evb->data, "id"));
518 if (eva->event == QAPI_EVENT_QUORUM_REPORT_BAD) {
519 return !strcmp(qdict_get_str(eva->data, "node-name"),
520 qdict_get_str(evb->data, "node-name"));
523 if (eva->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) {
524 return !strcmp(qdict_get_str(eva->data, "qom-path"),
525 qdict_get_str(evb->data, "qom-path"));
531 int monitor_suspend(Monitor *mon)
533 if (monitor_is_hmp_non_interactive(mon)) {
537 qatomic_inc(&mon->suspend_cnt);
539 if (mon->use_io_thread) {
541 * Kick I/O thread to make sure this takes effect. It'll be
542 * evaluated again in prepare() of the watch object.
544 aio_notify(iothread_get_aio_context(mon_iothread));
547 trace_monitor_suspend(mon, 1);
551 static void monitor_accept_input(void *opaque)
553 Monitor *mon = opaque;
555 qemu_mutex_lock(&mon->mon_lock);
556 if (!monitor_is_qmp(mon) && mon->reset_seen) {
557 MonitorHMP *hmp_mon = container_of(mon, MonitorHMP, common);
559 readline_restart(hmp_mon->rs);
560 qemu_mutex_unlock(&mon->mon_lock);
561 readline_show_prompt(hmp_mon->rs);
563 qemu_mutex_unlock(&mon->mon_lock);
566 qemu_chr_fe_accept_input(&mon->chr);
569 void monitor_resume(Monitor *mon)
571 if (monitor_is_hmp_non_interactive(mon)) {
575 if (qatomic_dec_fetch(&mon->suspend_cnt) == 0) {
578 if (mon->use_io_thread) {
579 ctx = iothread_get_aio_context(mon_iothread);
581 ctx = qemu_get_aio_context();
584 aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon);
587 trace_monitor_suspend(mon, -1);
590 int monitor_can_read(void *opaque)
592 Monitor *mon = opaque;
594 return !qatomic_read(&mon->suspend_cnt);
597 void monitor_list_append(Monitor *mon)
599 qemu_mutex_lock(&monitor_lock);
601 * This prevents inserting new monitors during monitor_cleanup().
602 * A cleaner solution would involve the main thread telling other
603 * threads to terminate, waiting for their termination.
605 if (!monitor_destroyed) {
606 QTAILQ_INSERT_HEAD(&mon_list, mon, entry);
609 qemu_mutex_unlock(&monitor_lock);
612 monitor_data_destroy(mon);
617 static void monitor_iothread_init(void)
619 mon_iothread = iothread_create("mon_iothread", &error_abort);
622 void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush,
625 if (use_io_thread && !mon_iothread) {
626 monitor_iothread_init();
628 qemu_mutex_init(&mon->mon_lock);
629 mon->is_qmp = is_qmp;
630 mon->outbuf = g_string_new(NULL);
631 mon->skip_flush = skip_flush;
632 mon->use_io_thread = use_io_thread;
635 void monitor_data_destroy(Monitor *mon)
637 g_free(mon->mon_cpu_path);
638 qemu_chr_fe_deinit(&mon->chr, false);
639 if (monitor_is_qmp(mon)) {
640 monitor_data_destroy_qmp(container_of(mon, MonitorQMP, common));
642 readline_free(container_of(mon, MonitorHMP, common)->rs);
644 g_string_free(mon->outbuf, true);
645 qemu_mutex_destroy(&mon->mon_lock);
648 void monitor_cleanup(void)
651 * The dispatcher needs to stop before destroying the monitor and
654 * We need to poll both qemu_aio_context and iohandler_ctx to make
655 * sure that the dispatcher coroutine keeps making progress and
656 * eventually terminates. qemu_aio_context is automatically
657 * polled by calling AIO_WAIT_WHILE_UNLOCKED on it, but we must poll
658 * iohandler_ctx manually.
660 * Letting the iothread continue while shutting down the dispatcher
661 * means that new requests may still be coming in. This is okay,
662 * we'll just leave them in the queue without sending a response
663 * and monitor_data_destroy() will free them.
665 WITH_QEMU_LOCK_GUARD(&monitor_lock) {
666 qmp_dispatcher_co_shutdown = true;
668 qmp_dispatcher_co_wake();
670 AIO_WAIT_WHILE_UNLOCKED(NULL,
671 (aio_poll(iohandler_get_aio_context(), false),
672 qatomic_read(&qmp_dispatcher_co)));
675 * We need to explicitly stop the I/O thread (but not destroy it),
676 * clean up the monitor resources, then destroy the I/O thread since
677 * we need to unregister from chardev below in
678 * monitor_data_destroy(), and chardev is not thread-safe yet
681 iothread_stop(mon_iothread);
684 /* Flush output buffers and destroy monitors */
685 qemu_mutex_lock(&monitor_lock);
686 monitor_destroyed = true;
687 while (!QTAILQ_EMPTY(&mon_list)) {
688 Monitor *mon = QTAILQ_FIRST(&mon_list);
689 QTAILQ_REMOVE(&mon_list, mon, entry);
690 /* Permit QAPI event emission from character frontend release */
691 qemu_mutex_unlock(&monitor_lock);
693 monitor_data_destroy(mon);
694 qemu_mutex_lock(&monitor_lock);
697 qemu_mutex_unlock(&monitor_lock);
700 iothread_destroy(mon_iothread);
705 static void monitor_qapi_event_init(void)
707 monitor_qapi_event_state = g_hash_table_new(qapi_event_throttle_hash,
708 qapi_event_throttle_equal);
711 void monitor_init_globals(void)
713 monitor_qapi_event_init();
714 qemu_mutex_init(&monitor_lock);
715 coroutine_mon = g_hash_table_new(NULL, NULL);
718 * The dispatcher BH must run in the main loop thread, since we
719 * have commands assuming that context. It would be nice to get
720 * rid of those assumptions.
722 qmp_dispatcher_co = qemu_coroutine_create(monitor_qmp_dispatcher_co, NULL);
723 aio_co_schedule(iohandler_get_aio_context(), qmp_dispatcher_co);
726 int monitor_init(MonitorOptions *opts, bool allow_hmp, Error **errp)
731 chr = qemu_chr_find(opts->chardev);
733 error_setg(errp, "chardev \"%s\" not found", opts->chardev);
737 if (!opts->has_mode) {
738 opts->mode = allow_hmp ? MONITOR_MODE_READLINE : MONITOR_MODE_CONTROL;
741 switch (opts->mode) {
742 case MONITOR_MODE_CONTROL:
743 monitor_init_qmp(chr, opts->pretty, errp);
745 case MONITOR_MODE_READLINE:
747 error_setg(errp, "Only QMP is supported");
751 error_setg(errp, "'pretty' is not compatible with HMP monitors");
754 monitor_init_hmp(chr, true, errp);
757 g_assert_not_reached();
760 return *errp ? -1 : 0;
763 int monitor_init_opts(QemuOpts *opts, Error **errp)
766 MonitorOptions *options;
769 v = opts_visitor_new(opts);
770 visit_type_MonitorOptions(v, NULL, &options, errp);
776 ret = monitor_init(options, true, errp);
777 qapi_free_MonitorOptions(options);
781 QemuOptsList qemu_mon_opts = {
783 .implied_opt_name = "chardev",
784 .head = QTAILQ_HEAD_INITIALIZER(qemu_mon_opts.head),
788 .type = QEMU_OPT_STRING,
791 .type = QEMU_OPT_STRING,
794 .type = QEMU_OPT_BOOL,
796 { /* end of list */ }