/*
* 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 "qapi/qmp/qstring.h"
#include "qemu/error-report.h"
#include "qemu/option.h"
#include "sysemu/qtest.h"
#include "sysemu/sysemu.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(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)
{
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;
}
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_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;
}
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 = qstring_new();
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);
}
qobject_unref(mon->outbuf);
qemu_mutex_destroy(&mon->mon_lock);
}
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);
}
/*
* 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.
*/
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)));
/* 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) {
warn_report("'pretty' is deprecated for HMP monitors, it has no "
"effect and will be removed in future versions");
}
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 */ }
},
};
