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
;
59 /* Set to true when the dispatcher coroutine should terminate */
60 bool qmp_dispatcher_co_shutdown
;
63 * qmp_dispatcher_co_busy is used for synchronisation between the
64 * monitor thread and the main thread to ensure that the dispatcher
65 * coroutine never gets scheduled a second time when it's already
66 * scheduled (scheduling the same coroutine twice is forbidden).
68 * It is true if the coroutine is active and processing requests.
69 * Additional requests may then be pushed onto mon->qmp_requests,
70 * and @qmp_dispatcher_co_shutdown may be set without further ado.
71 * @qmp_dispatcher_co_busy must not be woken up in this case.
73 * If false, you also have to set @qmp_dispatcher_co_busy to true and
74 * wake up @qmp_dispatcher_co after pushing the new requests.
76 * The coroutine will automatically change this variable back to false
77 * before it yields. Nobody else may set the variable to false.
79 * Access must be atomic for thread safety.
81 bool qmp_dispatcher_co_busy
;
84 * Protects mon_list, monitor_qapi_event_state, coroutine_mon,
87 QemuMutex monitor_lock
;
88 static GHashTable
*monitor_qapi_event_state
;
89 static GHashTable
*coroutine_mon
; /* Maps Coroutine* to Monitor* */
93 static bool monitor_destroyed
;
95 Monitor
*monitor_cur(void)
99 qemu_mutex_lock(&monitor_lock
);
100 mon
= g_hash_table_lookup(coroutine_mon
, qemu_coroutine_self());
101 qemu_mutex_unlock(&monitor_lock
);
107 * Sets a new current monitor and returns the old one.
109 * If a non-NULL monitor is set for a coroutine, another call
110 * resetting it to NULL is required before the coroutine terminates,
111 * otherwise a stale entry would remain in the hash table.
113 Monitor
*monitor_set_cur(Coroutine
*co
, Monitor
*mon
)
115 Monitor
*old_monitor
= monitor_cur();
117 qemu_mutex_lock(&monitor_lock
);
119 g_hash_table_replace(coroutine_mon
, co
, mon
);
121 g_hash_table_remove(coroutine_mon
, co
);
123 qemu_mutex_unlock(&monitor_lock
);
129 * Is the current monitor, if any, a QMP monitor?
131 bool monitor_cur_is_qmp(void)
133 Monitor
*cur_mon
= monitor_cur();
135 return cur_mon
&& monitor_is_qmp(cur_mon
);
139 * Is @mon is using readline?
140 * Note: not all HMP monitors use readline, e.g., gdbserver has a
141 * non-interactive HMP monitor, so readline is not used there.
143 static inline bool monitor_uses_readline(const MonitorHMP
*mon
)
145 return mon
->use_readline
;
148 static inline bool monitor_is_hmp_non_interactive(const Monitor
*mon
)
150 if (monitor_is_qmp(mon
)) {
154 return !monitor_uses_readline(container_of(mon
, MonitorHMP
, common
));
157 static void monitor_flush_locked(Monitor
*mon
);
159 static gboolean
monitor_unblocked(void *do_not_use
, GIOCondition cond
,
162 Monitor
*mon
= opaque
;
164 qemu_mutex_lock(&mon
->mon_lock
);
166 monitor_flush_locked(mon
);
167 qemu_mutex_unlock(&mon
->mon_lock
);
171 /* Caller must hold mon->mon_lock */
172 static void monitor_flush_locked(Monitor
*mon
)
178 if (mon
->skip_flush
) {
182 buf
= mon
->outbuf
->str
;
183 len
= mon
->outbuf
->len
;
185 if (len
&& !mon
->mux_out
) {
186 rc
= qemu_chr_fe_write(&mon
->chr
, (const uint8_t *) buf
, len
);
187 if ((rc
< 0 && errno
!= EAGAIN
) || (rc
== len
)) {
188 /* all flushed or error */
189 g_string_truncate(mon
->outbuf
, 0);
194 g_string_erase(mon
->outbuf
, 0, rc
);
196 if (mon
->out_watch
== 0) {
198 qemu_chr_fe_add_watch(&mon
->chr
, G_IO_OUT
| G_IO_HUP
,
199 monitor_unblocked
, mon
);
204 void monitor_flush(Monitor
*mon
)
206 qemu_mutex_lock(&mon
->mon_lock
);
207 monitor_flush_locked(mon
);
208 qemu_mutex_unlock(&mon
->mon_lock
);
211 /* flush at every end of line */
212 int monitor_puts(Monitor
*mon
, const char *str
)
217 qemu_mutex_lock(&mon
->mon_lock
);
218 for (i
= 0; str
[i
]; i
++) {
221 g_string_append_c(mon
->outbuf
, '\r');
223 g_string_append_c(mon
->outbuf
, c
);
225 monitor_flush_locked(mon
);
228 qemu_mutex_unlock(&mon
->mon_lock
);
233 int monitor_vprintf(Monitor
*mon
, const char *fmt
, va_list ap
)
242 if (monitor_is_qmp(mon
)) {
246 buf
= g_strdup_vprintf(fmt
, ap
);
247 n
= monitor_puts(mon
, buf
);
252 int monitor_printf(Monitor
*mon
, const char *fmt
, ...)
258 ret
= monitor_vprintf(mon
, fmt
, ap
);
264 * Print to current monitor if we have one, else to stderr.
266 int error_vprintf(const char *fmt
, va_list ap
)
268 Monitor
*cur_mon
= monitor_cur();
270 if (cur_mon
&& !monitor_cur_is_qmp()) {
271 return monitor_vprintf(cur_mon
, fmt
, ap
);
273 return vfprintf(stderr
, fmt
, ap
);
276 int error_vprintf_unless_qmp(const char *fmt
, va_list ap
)
278 Monitor
*cur_mon
= monitor_cur();
281 return vfprintf(stderr
, fmt
, ap
);
283 if (!monitor_cur_is_qmp()) {
284 return monitor_vprintf(cur_mon
, fmt
, ap
);
290 static MonitorQAPIEventConf monitor_qapi_event_conf
[QAPI_EVENT__MAX
] = {
291 /* Limit guest-triggerable events to 1 per second */
292 [QAPI_EVENT_RTC_CHANGE
] = { 1000 * SCALE_MS
},
293 [QAPI_EVENT_WATCHDOG
] = { 1000 * SCALE_MS
},
294 [QAPI_EVENT_BALLOON_CHANGE
] = { 1000 * SCALE_MS
},
295 [QAPI_EVENT_QUORUM_REPORT_BAD
] = { 1000 * SCALE_MS
},
296 [QAPI_EVENT_QUORUM_FAILURE
] = { 1000 * SCALE_MS
},
297 [QAPI_EVENT_VSERPORT_CHANGE
] = { 1000 * SCALE_MS
},
298 [QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE
] = { 1000 * SCALE_MS
},
302 * Return the clock to use for recording an event's time.
303 * It's QEMU_CLOCK_REALTIME, except for qtests it's
304 * QEMU_CLOCK_VIRTUAL, to support testing rate limits.
305 * Beware: result is invalid before configure_accelerator().
307 static inline QEMUClockType
monitor_get_event_clock(void)
309 return qtest_enabled() ? QEMU_CLOCK_VIRTUAL
: QEMU_CLOCK_REALTIME
;
313 * Broadcast an event to all monitors.
314 * @qdict is the event object. Its member "event" must match @event.
315 * Caller must hold monitor_lock.
317 static void monitor_qapi_event_emit(QAPIEvent event
, QDict
*qdict
)
322 trace_monitor_protocol_event_emit(event
, qdict
);
323 QTAILQ_FOREACH(mon
, &mon_list
, entry
) {
324 if (!monitor_is_qmp(mon
)) {
328 qmp_mon
= container_of(mon
, MonitorQMP
, common
);
329 if (qmp_mon
->commands
!= &qmp_cap_negotiation_commands
) {
330 qmp_send_response(qmp_mon
, qdict
);
335 static void monitor_qapi_event_handler(void *opaque
);
338 * Queue a new event for emission to Monitor instances,
339 * applying any rate limiting if required.
342 monitor_qapi_event_queue_no_reenter(QAPIEvent event
, QDict
*qdict
)
344 MonitorQAPIEventConf
*evconf
;
345 MonitorQAPIEventState
*evstate
;
347 assert(event
< QAPI_EVENT__MAX
);
348 evconf
= &monitor_qapi_event_conf
[event
];
349 trace_monitor_protocol_event_queue(event
, qdict
, evconf
->rate
);
351 QEMU_LOCK_GUARD(&monitor_lock
);
354 /* Unthrottled event */
355 monitor_qapi_event_emit(event
, qdict
);
357 QDict
*data
= qobject_to(QDict
, qdict_get(qdict
, "data"));
358 MonitorQAPIEventState key
= { .event
= event
, .data
= data
};
360 evstate
= g_hash_table_lookup(monitor_qapi_event_state
, &key
);
361 assert(!evstate
|| timer_pending(evstate
->timer
));
365 * Timer is pending for (at least) evconf->rate ns after
366 * last send. Store event for sending when timer fires,
367 * replacing a prior stored event if any.
369 qobject_unref(evstate
->qdict
);
370 evstate
->qdict
= qobject_ref(qdict
);
373 * Last send was (at least) evconf->rate ns ago.
374 * Send immediately, and arm the timer to call
375 * monitor_qapi_event_handler() in evconf->rate ns. Any
376 * events arriving before then will be delayed until then.
378 int64_t now
= qemu_clock_get_ns(monitor_get_event_clock());
380 monitor_qapi_event_emit(event
, qdict
);
382 evstate
= g_new(MonitorQAPIEventState
, 1);
383 evstate
->event
= event
;
384 evstate
->data
= qobject_ref(data
);
385 evstate
->qdict
= NULL
;
386 evstate
->timer
= timer_new_ns(monitor_get_event_clock(),
387 monitor_qapi_event_handler
,
389 g_hash_table_add(monitor_qapi_event_state
, evstate
);
390 timer_mod_ns(evstate
->timer
, now
+ evconf
->rate
);
395 void qapi_event_emit(QAPIEvent event
, QDict
*qdict
)
398 * monitor_qapi_event_queue_no_reenter() is not reentrant: it
399 * would deadlock on monitor_lock. Work around by queueing
400 * events in thread-local storage.
401 * TODO: remove this, make it re-enter safe.
403 typedef struct MonitorQapiEvent
{
406 QSIMPLEQ_ENTRY(MonitorQapiEvent
) entry
;
408 static __thread
QSIMPLEQ_HEAD(, MonitorQapiEvent
) event_queue
;
409 static __thread
bool reentered
;
410 MonitorQapiEvent
*ev
;
413 QSIMPLEQ_INIT(&event_queue
);
416 ev
= g_new(MonitorQapiEvent
, 1);
417 ev
->qdict
= qobject_ref(qdict
);
419 QSIMPLEQ_INSERT_TAIL(&event_queue
, ev
, entry
);
426 while ((ev
= QSIMPLEQ_FIRST(&event_queue
)) != NULL
) {
427 QSIMPLEQ_REMOVE_HEAD(&event_queue
, entry
);
428 monitor_qapi_event_queue_no_reenter(ev
->event
, ev
->qdict
);
429 qobject_unref(ev
->qdict
);
437 * This function runs evconf->rate ns after sending a throttled
439 * If another event has since been stored, send it.
441 static void monitor_qapi_event_handler(void *opaque
)
443 MonitorQAPIEventState
*evstate
= opaque
;
444 MonitorQAPIEventConf
*evconf
= &monitor_qapi_event_conf
[evstate
->event
];
446 trace_monitor_protocol_event_handler(evstate
->event
, evstate
->qdict
);
447 QEMU_LOCK_GUARD(&monitor_lock
);
449 if (evstate
->qdict
) {
450 int64_t now
= qemu_clock_get_ns(monitor_get_event_clock());
452 monitor_qapi_event_emit(evstate
->event
, evstate
->qdict
);
453 qobject_unref(evstate
->qdict
);
454 evstate
->qdict
= NULL
;
455 timer_mod_ns(evstate
->timer
, now
+ evconf
->rate
);
457 g_hash_table_remove(monitor_qapi_event_state
, evstate
);
458 qobject_unref(evstate
->data
);
459 timer_free(evstate
->timer
);
464 static unsigned int qapi_event_throttle_hash(const void *key
)
466 const MonitorQAPIEventState
*evstate
= key
;
467 unsigned int hash
= evstate
->event
* 255;
469 if (evstate
->event
== QAPI_EVENT_VSERPORT_CHANGE
) {
470 hash
+= g_str_hash(qdict_get_str(evstate
->data
, "id"));
473 if (evstate
->event
== QAPI_EVENT_QUORUM_REPORT_BAD
) {
474 hash
+= g_str_hash(qdict_get_str(evstate
->data
, "node-name"));
477 if (evstate
->event
== QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE
) {
478 hash
+= g_str_hash(qdict_get_str(evstate
->data
, "qom-path"));
484 static gboolean
qapi_event_throttle_equal(const void *a
, const void *b
)
486 const MonitorQAPIEventState
*eva
= a
;
487 const MonitorQAPIEventState
*evb
= b
;
489 if (eva
->event
!= evb
->event
) {
493 if (eva
->event
== QAPI_EVENT_VSERPORT_CHANGE
) {
494 return !strcmp(qdict_get_str(eva
->data
, "id"),
495 qdict_get_str(evb
->data
, "id"));
498 if (eva
->event
== QAPI_EVENT_QUORUM_REPORT_BAD
) {
499 return !strcmp(qdict_get_str(eva
->data
, "node-name"),
500 qdict_get_str(evb
->data
, "node-name"));
503 if (eva
->event
== QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE
) {
504 return !strcmp(qdict_get_str(eva
->data
, "qom-path"),
505 qdict_get_str(evb
->data
, "qom-path"));
511 int monitor_suspend(Monitor
*mon
)
513 if (monitor_is_hmp_non_interactive(mon
)) {
517 qatomic_inc(&mon
->suspend_cnt
);
519 if (mon
->use_io_thread
) {
521 * Kick I/O thread to make sure this takes effect. It'll be
522 * evaluated again in prepare() of the watch object.
524 aio_notify(iothread_get_aio_context(mon_iothread
));
527 trace_monitor_suspend(mon
, 1);
531 static void monitor_accept_input(void *opaque
)
533 Monitor
*mon
= opaque
;
535 qemu_chr_fe_accept_input(&mon
->chr
);
538 void monitor_resume(Monitor
*mon
)
540 if (monitor_is_hmp_non_interactive(mon
)) {
544 if (qatomic_dec_fetch(&mon
->suspend_cnt
) == 0) {
547 if (mon
->use_io_thread
) {
548 ctx
= iothread_get_aio_context(mon_iothread
);
550 ctx
= qemu_get_aio_context();
553 if (!monitor_is_qmp(mon
)) {
554 MonitorHMP
*hmp_mon
= container_of(mon
, MonitorHMP
, common
);
556 readline_show_prompt(hmp_mon
->rs
);
559 aio_bh_schedule_oneshot(ctx
, monitor_accept_input
, mon
);
562 trace_monitor_suspend(mon
, -1);
565 int monitor_can_read(void *opaque
)
567 Monitor
*mon
= opaque
;
569 return !qatomic_mb_read(&mon
->suspend_cnt
);
572 void monitor_list_append(Monitor
*mon
)
574 qemu_mutex_lock(&monitor_lock
);
576 * This prevents inserting new monitors during monitor_cleanup().
577 * A cleaner solution would involve the main thread telling other
578 * threads to terminate, waiting for their termination.
580 if (!monitor_destroyed
) {
581 QTAILQ_INSERT_HEAD(&mon_list
, mon
, entry
);
584 qemu_mutex_unlock(&monitor_lock
);
587 monitor_data_destroy(mon
);
592 static void monitor_iothread_init(void)
594 mon_iothread
= iothread_create("mon_iothread", &error_abort
);
597 void monitor_data_init(Monitor
*mon
, bool is_qmp
, bool skip_flush
,
600 if (use_io_thread
&& !mon_iothread
) {
601 monitor_iothread_init();
603 qemu_mutex_init(&mon
->mon_lock
);
604 mon
->is_qmp
= is_qmp
;
605 mon
->outbuf
= g_string_new(NULL
);
606 mon
->skip_flush
= skip_flush
;
607 mon
->use_io_thread
= use_io_thread
;
610 void monitor_data_destroy(Monitor
*mon
)
612 g_free(mon
->mon_cpu_path
);
613 qemu_chr_fe_deinit(&mon
->chr
, false);
614 if (monitor_is_qmp(mon
)) {
615 monitor_data_destroy_qmp(container_of(mon
, MonitorQMP
, common
));
617 readline_free(container_of(mon
, MonitorHMP
, common
)->rs
);
619 g_string_free(mon
->outbuf
, true);
620 qemu_mutex_destroy(&mon
->mon_lock
);
623 void monitor_cleanup(void)
626 * The dispatcher needs to stop before destroying the monitor and
629 * We need to poll both qemu_aio_context and iohandler_ctx to make
630 * sure that the dispatcher coroutine keeps making progress and
631 * eventually terminates. qemu_aio_context is automatically
632 * polled by calling AIO_WAIT_WHILE on it, but we must poll
633 * iohandler_ctx manually.
635 * Letting the iothread continue while shutting down the dispatcher
636 * means that new requests may still be coming in. This is okay,
637 * we'll just leave them in the queue without sending a response
638 * and monitor_data_destroy() will free them.
640 qmp_dispatcher_co_shutdown
= true;
641 if (!qatomic_xchg(&qmp_dispatcher_co_busy
, true)) {
642 aio_co_wake(qmp_dispatcher_co
);
645 AIO_WAIT_WHILE(qemu_get_aio_context(),
646 (aio_poll(iohandler_get_aio_context(), false),
647 qatomic_mb_read(&qmp_dispatcher_co_busy
)));
650 * We need to explicitly stop the I/O thread (but not destroy it),
651 * clean up the monitor resources, then destroy the I/O thread since
652 * we need to unregister from chardev below in
653 * monitor_data_destroy(), and chardev is not thread-safe yet
656 iothread_stop(mon_iothread
);
659 /* Flush output buffers and destroy monitors */
660 qemu_mutex_lock(&monitor_lock
);
661 monitor_destroyed
= true;
662 while (!QTAILQ_EMPTY(&mon_list
)) {
663 Monitor
*mon
= QTAILQ_FIRST(&mon_list
);
664 QTAILQ_REMOVE(&mon_list
, mon
, entry
);
665 /* Permit QAPI event emission from character frontend release */
666 qemu_mutex_unlock(&monitor_lock
);
668 monitor_data_destroy(mon
);
669 qemu_mutex_lock(&monitor_lock
);
672 qemu_mutex_unlock(&monitor_lock
);
675 iothread_destroy(mon_iothread
);
680 static void monitor_qapi_event_init(void)
682 monitor_qapi_event_state
= g_hash_table_new(qapi_event_throttle_hash
,
683 qapi_event_throttle_equal
);
686 void monitor_init_globals_core(void)
688 monitor_qapi_event_init();
689 qemu_mutex_init(&monitor_lock
);
690 coroutine_mon
= g_hash_table_new(NULL
, NULL
);
693 * The dispatcher BH must run in the main loop thread, since we
694 * have commands assuming that context. It would be nice to get
695 * rid of those assumptions.
697 qmp_dispatcher_co
= qemu_coroutine_create(monitor_qmp_dispatcher_co
, NULL
);
698 qatomic_mb_set(&qmp_dispatcher_co_busy
, true);
699 aio_co_schedule(iohandler_get_aio_context(), qmp_dispatcher_co
);
702 int monitor_init(MonitorOptions
*opts
, bool allow_hmp
, Error
**errp
)
705 Error
*local_err
= NULL
;
707 chr
= qemu_chr_find(opts
->chardev
);
709 error_setg(errp
, "chardev \"%s\" not found", opts
->chardev
);
713 if (!opts
->has_mode
) {
714 opts
->mode
= allow_hmp
? MONITOR_MODE_READLINE
: MONITOR_MODE_CONTROL
;
717 switch (opts
->mode
) {
718 case MONITOR_MODE_CONTROL
:
719 monitor_init_qmp(chr
, opts
->pretty
, &local_err
);
721 case MONITOR_MODE_READLINE
:
723 error_setg(errp
, "Only QMP is supported");
727 error_setg(errp
, "'pretty' is not compatible with HMP monitors");
730 monitor_init_hmp(chr
, true, &local_err
);
733 g_assert_not_reached();
737 error_propagate(errp
, local_err
);
743 int monitor_init_opts(QemuOpts
*opts
, Error
**errp
)
746 MonitorOptions
*options
;
749 v
= opts_visitor_new(opts
);
750 visit_type_MonitorOptions(v
, NULL
, &options
, errp
);
756 ret
= monitor_init(options
, true, errp
);
757 qapi_free_MonitorOptions(options
);
761 QemuOptsList qemu_mon_opts
= {
763 .implied_opt_name
= "chardev",
764 .head
= QTAILQ_HEAD_INITIALIZER(qemu_mon_opts
.head
),
768 .type
= QEMU_OPT_STRING
,
771 .type
= QEMU_OPT_STRING
,
774 .type
= QEMU_OPT_BOOL
,
776 { /* end of list */ }