diff options
Diffstat (limited to 'monitor/monitor.c')
| -rw-r--r-- | monitor/monitor.c | 633 |
1 files changed, 633 insertions, 0 deletions
diff --git a/monitor/monitor.c b/monitor/monitor.c new file mode 100644 index 0000000000..db3d5ece99 --- /dev/null +++ b/monitor/monitor.c @@ -0,0 +1,633 @@ +/* + * 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/qapi-emit-events.h" +#include "qapi/qmp/qdict.h" +#include "qapi/qmp/qstring.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; + +/* Bottom half to dispatch the requests received from I/O thread */ +QEMUBH *qmp_dispatcher_bh; + +/* Protects mon_list, monitor_qapi_event_state, monitor_destroyed. */ +QemuMutex monitor_lock; +static GHashTable *monitor_qapi_event_state; + +MonitorList mon_list; +int mon_refcount; +static bool monitor_destroyed; + +__thread Monitor *cur_mon; + +/** + * Is the current monitor, if any, a QMP monitor? + */ +bool monitor_cur_is_qmp(void) +{ + 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 Monitor *mon) +{ + return mon->flags & MONITOR_USE_READLINE; +} + +static inline bool monitor_is_hmp_non_interactive(const Monitor *mon) +{ + return !monitor_is_qmp(mon) && !monitor_uses_readline(mon); +} + +static void monitor_flush_locked(Monitor *mon); + +static gboolean monitor_unblocked(GIOChannel *chan, 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 = qstring_get_str(mon->outbuf); + len = qstring_get_length(mon->outbuf); + + 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 */ + qobject_unref(mon->outbuf); + mon->outbuf = qstring_new(); + return; + } + if (rc > 0) { + /* partial write */ + QString *tmp = qstring_from_str(buf + rc); + qobject_unref(mon->outbuf); + mon->outbuf = tmp; + } + 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') { + qstring_append_chr(mon->outbuf, '\r'); + } + qstring_append_chr(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) +{ + 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) +{ + if (!cur_mon) { + return vfprintf(stderr, fmt, ap); + } + if (!monitor_cur_is_qmp()) { + return monitor_vprintf(cur_mon, fmt, ap); + } + return -1; +} + + +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 }, +}; + +/* + * 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_mutex_lock(&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); + } + } + + qemu_mutex_unlock(&monitor_lock); +} + +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_mutex_lock(&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); + } + + qemu_mutex_unlock(&monitor_lock); +} + +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")); + } + + 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")); + } + + return TRUE; +} + +int monitor_suspend(Monitor *mon) +{ + if (monitor_is_hmp_non_interactive(mon)) { + return -ENOTTY; + } + + atomic_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 (atomic_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 !atomic_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, int flags, bool skip_flush, + bool use_io_thread) +{ + if (use_io_thread && !mon_iothread) { + monitor_iothread_init(); + } + qemu_mutex_init(&mon->mon_lock); + mon->outbuf = qstring_new(); + mon->skip_flush = skip_flush; + mon->use_io_thread = use_io_thread; + mon->flags = flags; +} + +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); + } + qobject_unref(mon->outbuf); + qemu_mutex_destroy(&mon->mon_lock); +} + +void monitor_init(Chardev *chr, int flags) +{ + if (flags & MONITOR_USE_CONTROL) { + monitor_init_qmp(chr, flags); + } else { + monitor_init_hmp(chr, flags); + } +} + +void monitor_cleanup(void) +{ + /* + * 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); + + /* QEMUBHs needs to be deleted before destroying the I/O thread */ + qemu_bh_delete(qmp_dispatcher_bh); + qmp_dispatcher_bh = NULL; + 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); + + /* + * 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_bh = aio_bh_new(iohandler_get_aio_context(), + monitor_qmp_bh_dispatcher, + NULL); +} + +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 */ } + }, +}; |