/* * QEMU monitor * * Copyright (c) 2003-2004 Fabrice Bellard * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ #include "qemu/osdep.h" #include "monitor-internal.h" #include "qapi/error.h" #include "qapi/opts-visitor.h" #include "qapi/qapi-emit-events.h" #include "qapi/qapi-visit-control.h" #include "qapi/qmp/qdict.h" #include "qemu/error-report.h" #include "qemu/option.h" #include "sysemu/qtest.h" #include "trace.h" /* * To prevent flooding clients, events can be throttled. The * throttling is calculated globally, rather than per-Monitor * instance. */ typedef struct MonitorQAPIEventState { QAPIEvent event; /* Throttling state for this event type and... */ QDict *data; /* ... data, see qapi_event_throttle_equal() */ QEMUTimer *timer; /* Timer for handling delayed events */ QDict *qdict; /* Delayed event (if any) */ } MonitorQAPIEventState; typedef struct { int64_t rate; /* Minimum time (in ns) between two events */ } MonitorQAPIEventConf; /* Shared monitor I/O thread */ IOThread *mon_iothread; /* Coroutine to dispatch the requests received from I/O thread */ Coroutine *qmp_dispatcher_co; /* Set to true when the dispatcher coroutine should terminate */ bool qmp_dispatcher_co_shutdown; /* * qmp_dispatcher_co_busy is used for synchronisation between the * monitor thread and the main thread to ensure that the dispatcher * coroutine never gets scheduled a second time when it's already * scheduled (scheduling the same coroutine twice is forbidden). * * It is true if the coroutine is active and processing requests. * Additional requests may then be pushed onto mon->qmp_requests, * and @qmp_dispatcher_co_shutdown may be set without further ado. * @qmp_dispatcher_co_busy must not be woken up in this case. * * If false, you also have to set @qmp_dispatcher_co_busy to true and * wake up @qmp_dispatcher_co after pushing the new requests. * * The coroutine will automatically change this variable back to false * before it yields. Nobody else may set the variable to false. * * Access must be atomic for thread safety. */ bool qmp_dispatcher_co_busy; /* * Protects mon_list, monitor_qapi_event_state, coroutine_mon, * monitor_destroyed. */ QemuMutex monitor_lock; static GHashTable *monitor_qapi_event_state; static GHashTable *coroutine_mon; /* Maps Coroutine* to Monitor* */ MonitorList mon_list; int mon_refcount; static bool monitor_destroyed; Monitor *monitor_cur(void) { Monitor *mon; qemu_mutex_lock(&monitor_lock); mon = g_hash_table_lookup(coroutine_mon, qemu_coroutine_self()); qemu_mutex_unlock(&monitor_lock); return mon; } /** * Sets a new current monitor and returns the old one. * * If a non-NULL monitor is set for a coroutine, another call * resetting it to NULL is required before the coroutine terminates, * otherwise a stale entry would remain in the hash table. */ Monitor *monitor_set_cur(Coroutine *co, Monitor *mon) { Monitor *old_monitor = monitor_cur(); qemu_mutex_lock(&monitor_lock); if (mon) { g_hash_table_replace(coroutine_mon, co, mon); } else { g_hash_table_remove(coroutine_mon, co); } qemu_mutex_unlock(&monitor_lock); return old_monitor; } /** * Is the current monitor, if any, a QMP monitor? */ bool monitor_cur_is_qmp(void) { Monitor *cur_mon = monitor_cur(); return cur_mon && monitor_is_qmp(cur_mon); } /** * Is @mon is using readline? * Note: not all HMP monitors use readline, e.g., gdbserver has a * non-interactive HMP monitor, so readline is not used there. */ static inline bool monitor_uses_readline(const MonitorHMP *mon) { return mon->use_readline; } static inline bool monitor_is_hmp_non_interactive(const Monitor *mon) { if (monitor_is_qmp(mon)) { return false; } return !monitor_uses_readline(container_of(mon, MonitorHMP, common)); } static void monitor_flush_locked(Monitor *mon); static gboolean monitor_unblocked(void *do_not_use, GIOCondition cond, void *opaque) { Monitor *mon = opaque; QEMU_LOCK_GUARD(&mon->mon_lock); mon->out_watch = 0; monitor_flush_locked(mon); return FALSE; } /* Caller must hold mon->mon_lock */ static void monitor_flush_locked(Monitor *mon) { int rc; size_t len; const char *buf; if (mon->skip_flush) { return; } buf = mon->outbuf->str; len = mon->outbuf->len; if (len && !mon->mux_out) { rc = qemu_chr_fe_write(&mon->chr, (const uint8_t *) buf, len); if ((rc < 0 && errno != EAGAIN) || (rc == len)) { /* all flushed or error */ g_string_truncate(mon->outbuf, 0); return; } if (rc > 0) { /* partial write */ g_string_erase(mon->outbuf, 0, rc); } if (mon->out_watch == 0) { mon->out_watch = qemu_chr_fe_add_watch(&mon->chr, G_IO_OUT | G_IO_HUP, monitor_unblocked, mon); } } } void monitor_flush(Monitor *mon) { QEMU_LOCK_GUARD(&mon->mon_lock); monitor_flush_locked(mon); } /* flush at every end of line */ int monitor_puts(Monitor *mon, const char *str) { int i; char c; qemu_mutex_lock(&mon->mon_lock); for (i = 0; str[i]; i++) { c = str[i]; if (c == '\n') { g_string_append_c(mon->outbuf, '\r'); } g_string_append_c(mon->outbuf, c); if (c == '\n') { monitor_flush_locked(mon); } } qemu_mutex_unlock(&mon->mon_lock); return i; } int monitor_vprintf(Monitor *mon, const char *fmt, va_list ap) { char *buf; int n; if (!mon) { return -1; } if (monitor_is_qmp(mon)) { return -1; } buf = g_strdup_vprintf(fmt, ap); n = monitor_puts(mon, buf); g_free(buf); return n; } int monitor_printf(Monitor *mon, const char *fmt, ...) { int ret; va_list ap; va_start(ap, fmt); ret = monitor_vprintf(mon, fmt, ap); va_end(ap); return ret; } void monitor_printc(Monitor *mon, int c) { monitor_printf(mon, "'"); switch(c) { case '\'': monitor_printf(mon, "\\'"); break; case '\\': monitor_printf(mon, "\\\\"); break; case '\n': monitor_printf(mon, "\\n"); break; case '\r': monitor_printf(mon, "\\r"); break; default: if (c >= 32 && c <= 126) { monitor_printf(mon, "%c", c); } else { monitor_printf(mon, "\\x%02x", c); } break; } monitor_printf(mon, "'"); } /* * Print to current monitor if we have one, else to stderr. */ int error_vprintf(const char *fmt, va_list ap) { Monitor *cur_mon = monitor_cur(); if (cur_mon && !monitor_cur_is_qmp()) { return monitor_vprintf(cur_mon, fmt, ap); } return vfprintf(stderr, fmt, ap); } int error_vprintf_unless_qmp(const char *fmt, va_list ap) { Monitor *cur_mon = monitor_cur(); if (!cur_mon) { return vfprintf(stderr, fmt, ap); } if (!monitor_cur_is_qmp()) { return monitor_vprintf(cur_mon, fmt, ap); } return -1; } int error_printf_unless_qmp(const char *fmt, ...) { va_list ap; int ret; va_start(ap, fmt); ret = error_vprintf_unless_qmp(fmt, ap); va_end(ap); return ret; } static MonitorQAPIEventConf monitor_qapi_event_conf[QAPI_EVENT__MAX] = { /* Limit guest-triggerable events to 1 per second */ [QAPI_EVENT_RTC_CHANGE] = { 1000 * SCALE_MS }, [QAPI_EVENT_WATCHDOG] = { 1000 * SCALE_MS }, [QAPI_EVENT_BALLOON_CHANGE] = { 1000 * SCALE_MS }, [QAPI_EVENT_QUORUM_REPORT_BAD] = { 1000 * SCALE_MS }, [QAPI_EVENT_QUORUM_FAILURE] = { 1000 * SCALE_MS }, [QAPI_EVENT_VSERPORT_CHANGE] = { 1000 * SCALE_MS }, [QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE] = { 1000 * SCALE_MS }, }; /* * Return the clock to use for recording an event's time. * It's QEMU_CLOCK_REALTIME, except for qtests it's * QEMU_CLOCK_VIRTUAL, to support testing rate limits. * Beware: result is invalid before configure_accelerator(). */ static inline QEMUClockType monitor_get_event_clock(void) { return qtest_enabled() ? QEMU_CLOCK_VIRTUAL : QEMU_CLOCK_REALTIME; } /* * Broadcast an event to all monitors. * @qdict is the event object. Its member "event" must match @event. * Caller must hold monitor_lock. */ static void monitor_qapi_event_emit(QAPIEvent event, QDict *qdict) { Monitor *mon; MonitorQMP *qmp_mon; trace_monitor_protocol_event_emit(event, qdict); QTAILQ_FOREACH(mon, &mon_list, entry) { if (!monitor_is_qmp(mon)) { continue; } qmp_mon = container_of(mon, MonitorQMP, common); if (qmp_mon->commands != &qmp_cap_negotiation_commands) { qmp_send_response(qmp_mon, qdict); } } } static void monitor_qapi_event_handler(void *opaque); /* * Queue a new event for emission to Monitor instances, * applying any rate limiting if required. */ static void monitor_qapi_event_queue_no_reenter(QAPIEvent event, QDict *qdict) { MonitorQAPIEventConf *evconf; MonitorQAPIEventState *evstate; assert(event < QAPI_EVENT__MAX); evconf = &monitor_qapi_event_conf[event]; trace_monitor_protocol_event_queue(event, qdict, evconf->rate); QEMU_LOCK_GUARD(&monitor_lock); if (!evconf->rate) { /* Unthrottled event */ monitor_qapi_event_emit(event, qdict); } else { QDict *data = qobject_to(QDict, qdict_get(qdict, "data")); MonitorQAPIEventState key = { .event = event, .data = data }; evstate = g_hash_table_lookup(monitor_qapi_event_state, &key); assert(!evstate || timer_pending(evstate->timer)); if (evstate) { /* * Timer is pending for (at least) evconf->rate ns after * last send. Store event for sending when timer fires, * replacing a prior stored event if any. */ qobject_unref(evstate->qdict); evstate->qdict = qobject_ref(qdict); } else { /* * Last send was (at least) evconf->rate ns ago. * Send immediately, and arm the timer to call * monitor_qapi_event_handler() in evconf->rate ns. Any * events arriving before then will be delayed until then. */ int64_t now = qemu_clock_get_ns(monitor_get_event_clock()); monitor_qapi_event_emit(event, qdict); evstate = g_new(MonitorQAPIEventState, 1); evstate->event = event; evstate->data = qobject_ref(data); evstate->qdict = NULL; evstate->timer = timer_new_ns(monitor_get_event_clock(), monitor_qapi_event_handler, evstate); g_hash_table_add(monitor_qapi_event_state, evstate); timer_mod_ns(evstate->timer, now + evconf->rate); } } } void qapi_event_emit(QAPIEvent event, QDict *qdict) { /* * monitor_qapi_event_queue_no_reenter() is not reentrant: it * would deadlock on monitor_lock. Work around by queueing * events in thread-local storage. * TODO: remove this, make it re-enter safe. */ typedef struct MonitorQapiEvent { QAPIEvent event; QDict *qdict; QSIMPLEQ_ENTRY(MonitorQapiEvent) entry; } MonitorQapiEvent; static __thread QSIMPLEQ_HEAD(, MonitorQapiEvent) event_queue; static __thread bool reentered; MonitorQapiEvent *ev; if (!reentered) { QSIMPLEQ_INIT(&event_queue); } ev = g_new(MonitorQapiEvent, 1); ev->qdict = qobject_ref(qdict); ev->event = event; QSIMPLEQ_INSERT_TAIL(&event_queue, ev, entry); if (reentered) { return; } reentered = true; while ((ev = QSIMPLEQ_FIRST(&event_queue)) != NULL) { QSIMPLEQ_REMOVE_HEAD(&event_queue, entry); monitor_qapi_event_queue_no_reenter(ev->event, ev->qdict); qobject_unref(ev->qdict); g_free(ev); } reentered = false; } /* * This function runs evconf->rate ns after sending a throttled * event. * If another event has since been stored, send it. */ static void monitor_qapi_event_handler(void *opaque) { MonitorQAPIEventState *evstate = opaque; MonitorQAPIEventConf *evconf = &monitor_qapi_event_conf[evstate->event]; trace_monitor_protocol_event_handler(evstate->event, evstate->qdict); QEMU_LOCK_GUARD(&monitor_lock); if (evstate->qdict) { int64_t now = qemu_clock_get_ns(monitor_get_event_clock()); monitor_qapi_event_emit(evstate->event, evstate->qdict); qobject_unref(evstate->qdict); evstate->qdict = NULL; timer_mod_ns(evstate->timer, now + evconf->rate); } else { g_hash_table_remove(monitor_qapi_event_state, evstate); qobject_unref(evstate->data); timer_free(evstate->timer); g_free(evstate); } } static unsigned int qapi_event_throttle_hash(const void *key) { const MonitorQAPIEventState *evstate = key; unsigned int hash = evstate->event * 255; if (evstate->event == QAPI_EVENT_VSERPORT_CHANGE) { hash += g_str_hash(qdict_get_str(evstate->data, "id")); } if (evstate->event == QAPI_EVENT_QUORUM_REPORT_BAD) { hash += g_str_hash(qdict_get_str(evstate->data, "node-name")); } if (evstate->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) { hash += g_str_hash(qdict_get_str(evstate->data, "qom-path")); } return hash; } static gboolean qapi_event_throttle_equal(const void *a, const void *b) { const MonitorQAPIEventState *eva = a; const MonitorQAPIEventState *evb = b; if (eva->event != evb->event) { return FALSE; } if (eva->event == QAPI_EVENT_VSERPORT_CHANGE) { return !strcmp(qdict_get_str(eva->data, "id"), qdict_get_str(evb->data, "id")); } if (eva->event == QAPI_EVENT_QUORUM_REPORT_BAD) { return !strcmp(qdict_get_str(eva->data, "node-name"), qdict_get_str(evb->data, "node-name")); } if (eva->event == QAPI_EVENT_MEMORY_DEVICE_SIZE_CHANGE) { return !strcmp(qdict_get_str(eva->data, "qom-path"), qdict_get_str(evb->data, "qom-path")); } return TRUE; } int monitor_suspend(Monitor *mon) { if (monitor_is_hmp_non_interactive(mon)) { return -ENOTTY; } qatomic_inc(&mon->suspend_cnt); if (mon->use_io_thread) { /* * Kick I/O thread to make sure this takes effect. It'll be * evaluated again in prepare() of the watch object. */ aio_notify(iothread_get_aio_context(mon_iothread)); } trace_monitor_suspend(mon, 1); return 0; } static void monitor_accept_input(void *opaque) { Monitor *mon = opaque; qemu_chr_fe_accept_input(&mon->chr); } void monitor_resume(Monitor *mon) { if (monitor_is_hmp_non_interactive(mon)) { return; } if (qatomic_dec_fetch(&mon->suspend_cnt) == 0) { AioContext *ctx; if (mon->use_io_thread) { ctx = iothread_get_aio_context(mon_iothread); } else { ctx = qemu_get_aio_context(); } if (!monitor_is_qmp(mon)) { MonitorHMP *hmp_mon = container_of(mon, MonitorHMP, common); assert(hmp_mon->rs); readline_show_prompt(hmp_mon->rs); } aio_bh_schedule_oneshot(ctx, monitor_accept_input, mon); } trace_monitor_suspend(mon, -1); } int monitor_can_read(void *opaque) { Monitor *mon = opaque; return !qatomic_mb_read(&mon->suspend_cnt); } void monitor_list_append(Monitor *mon) { qemu_mutex_lock(&monitor_lock); /* * This prevents inserting new monitors during monitor_cleanup(). * A cleaner solution would involve the main thread telling other * threads to terminate, waiting for their termination. */ if (!monitor_destroyed) { QTAILQ_INSERT_HEAD(&mon_list, mon, entry); mon = NULL; } qemu_mutex_unlock(&monitor_lock); if (mon) { monitor_data_destroy(mon); g_free(mon); } } static void monitor_iothread_init(void) { mon_iothread = iothread_create("mon_iothread", &error_abort); } void monitor_data_init(Monitor *mon, bool is_qmp, bool skip_flush, bool use_io_thread) { if (use_io_thread && !mon_iothread) { monitor_iothread_init(); } qemu_mutex_init(&mon->mon_lock); mon->is_qmp = is_qmp; mon->outbuf = g_string_new(NULL); mon->skip_flush = skip_flush; mon->use_io_thread = use_io_thread; } void monitor_data_destroy(Monitor *mon) { g_free(mon->mon_cpu_path); qemu_chr_fe_deinit(&mon->chr, false); if (monitor_is_qmp(mon)) { monitor_data_destroy_qmp(container_of(mon, MonitorQMP, common)); } else { readline_free(container_of(mon, MonitorHMP, common)->rs); } g_string_free(mon->outbuf, true); qemu_mutex_destroy(&mon->mon_lock); } void monitor_cleanup(void) { /* * The dispatcher needs to stop before destroying the monitor and * the I/O thread. * * We need to poll both qemu_aio_context and iohandler_ctx to make * sure that the dispatcher coroutine keeps making progress and * eventually terminates. qemu_aio_context is automatically * polled by calling AIO_WAIT_WHILE_UNLOCKED on it, but we must poll * iohandler_ctx manually. * * Letting the iothread continue while shutting down the dispatcher * means that new requests may still be coming in. This is okay, * we'll just leave them in the queue without sending a response * and monitor_data_destroy() will free them. */ qmp_dispatcher_co_shutdown = true; if (!qatomic_xchg(&qmp_dispatcher_co_busy, true)) { aio_co_wake(qmp_dispatcher_co); } AIO_WAIT_WHILE_UNLOCKED(NULL, (aio_poll(iohandler_get_aio_context(), false), qatomic_mb_read(&qmp_dispatcher_co_busy))); /* * We need to explicitly stop the I/O thread (but not destroy it), * clean up the monitor resources, then destroy the I/O thread since * we need to unregister from chardev below in * monitor_data_destroy(), and chardev is not thread-safe yet */ if (mon_iothread) { iothread_stop(mon_iothread); } /* Flush output buffers and destroy monitors */ qemu_mutex_lock(&monitor_lock); monitor_destroyed = true; while (!QTAILQ_EMPTY(&mon_list)) { Monitor *mon = QTAILQ_FIRST(&mon_list); QTAILQ_REMOVE(&mon_list, mon, entry); /* Permit QAPI event emission from character frontend release */ qemu_mutex_unlock(&monitor_lock); monitor_flush(mon); monitor_data_destroy(mon); qemu_mutex_lock(&monitor_lock); g_free(mon); } qemu_mutex_unlock(&monitor_lock); if (mon_iothread) { iothread_destroy(mon_iothread); mon_iothread = NULL; } } static void monitor_qapi_event_init(void) { monitor_qapi_event_state = g_hash_table_new(qapi_event_throttle_hash, qapi_event_throttle_equal); } void monitor_init_globals(void) { monitor_qapi_event_init(); qemu_mutex_init(&monitor_lock); coroutine_mon = g_hash_table_new(NULL, NULL); /* * The dispatcher BH must run in the main loop thread, since we * have commands assuming that context. It would be nice to get * rid of those assumptions. */ qmp_dispatcher_co = qemu_coroutine_create(monitor_qmp_dispatcher_co, NULL); qatomic_mb_set(&qmp_dispatcher_co_busy, true); aio_co_schedule(iohandler_get_aio_context(), qmp_dispatcher_co); } int monitor_init(MonitorOptions *opts, bool allow_hmp, Error **errp) { ERRP_GUARD(); Chardev *chr; chr = qemu_chr_find(opts->chardev); if (chr == NULL) { error_setg(errp, "chardev \"%s\" not found", opts->chardev); return -1; } if (!opts->has_mode) { opts->mode = allow_hmp ? MONITOR_MODE_READLINE : MONITOR_MODE_CONTROL; } switch (opts->mode) { case MONITOR_MODE_CONTROL: monitor_init_qmp(chr, opts->pretty, errp); break; case MONITOR_MODE_READLINE: if (!allow_hmp) { error_setg(errp, "Only QMP is supported"); return -1; } if (opts->pretty) { error_setg(errp, "'pretty' is not compatible with HMP monitors"); return -1; } monitor_init_hmp(chr, true, errp); break; default: g_assert_not_reached(); } return *errp ? -1 : 0; } int monitor_init_opts(QemuOpts *opts, Error **errp) { Visitor *v; MonitorOptions *options; int ret; v = opts_visitor_new(opts); visit_type_MonitorOptions(v, NULL, &options, errp); visit_free(v); if (!options) { return -1; } ret = monitor_init(options, true, errp); qapi_free_MonitorOptions(options); return ret; } QemuOptsList qemu_mon_opts = { .name = "mon", .implied_opt_name = "chardev", .head = QTAILQ_HEAD_INITIALIZER(qemu_mon_opts.head), .desc = { { .name = "mode", .type = QEMU_OPT_STRING, },{ .name = "chardev", .type = QEMU_OPT_STRING, },{ .name = "pretty", .type = QEMU_OPT_BOOL, }, { /* end of list */ } }, };