qemu

monitor.c (22383B)

---

 /*
  * 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_mutex_lock(&mon->mon_lock);
     mon->out_watch = 0;
     monitor_flush_locked(mon);
     qemu_mutex_unlock(&mon->mon_lock);
     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_mutex_lock(&mon->mon_lock);
     monitor_flush_locked(mon);
     qemu_mutex_unlock(&mon->mon_lock);
 }
 
 /* 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;
 }
 
 /*
  * 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 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(qemu_get_aio_context(),
                    (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_core(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)
 {
     Chardev *chr;
     Error *local_err = NULL;
 
     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, &local_err);
         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, &local_err);
         break;
     default:
         g_assert_not_reached();
     }
 
     if (local_err) {
         error_propagate(errp, local_err);
         return -1;
     }
     return 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 */ }
     },
 };