monitor: Split out monitor/qmp.c

Move QMP infrastructure from monitor/misc.c to monitor/qmp.c. This is
code that can be shared for all targets, so compile it only once.

The amount of function and particularly extern variables in
monitor_int.h is probably a bit larger than it needs to be, but this way
no non-trivial code modifications are needed. The interfaces between QMP
and the monitor core can be cleaned up later.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Message-Id: <20190613153405.24769-11-kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
[monitor_is_qmp() tidied up to make checkpatch.pl happy,
superfluous #include dropped]
Signed-off-by: Markus Armbruster <armbru@redhat.com>

1 files changed, 9 insertions, 392 deletions

diff --git a/monitor/misc.c b/monitor/misc.c
index 3cdbb681fb..824d28d717 100644
--- a/monitor/misc.c
+++ b/monitor/misc.c
@@ -36,7 +36,6 @@
 #include "exec/gdbstub.h"
 #include "net/net.h"
 #include "net/slirp.h"
-#include "chardev/char-io.h"
 #include "chardev/char-mux.h"
 #include "ui/qemu-spice.h"
 #include "sysemu/numa.h"
@@ -58,8 +57,6 @@
 #include "qapi/qmp/qerror.h"
 #include "qapi/qmp/qnum.h"
 #include "qapi/qmp/qstring.h"
-#include "qapi/qmp/qjson.h"
-#include "qapi/qmp/qlist.h"
 #include "qom/object_interfaces.h"
 #include "trace.h"
 #include "trace/control.h"
@@ -81,7 +78,6 @@
 #include "qapi/qapi-introspect.h"
 #include "sysemu/qtest.h"
 #include "sysemu/cpus.h"
-#include "sysemu/iothread.h"
 #include "qemu/cutils.h"
 #include "tcg/tcg.h"
 
@@ -138,52 +134,30 @@ IOThread *mon_iothread;
 /* Bottom half to dispatch the requests received from I/O thread */
 QEMUBH *qmp_dispatcher_bh;
 
-struct QMPRequest {
-    /* Owner of the request */
-    MonitorQMP *mon;
-    /*
-     * Request object to be handled or Error to be reported
-     * (exactly one of them is non-null)
-     */
-    QObject *req;
-    Error *err;
-};
-typedef struct QMPRequest QMPRequest;
-
 /* QMP checker flags */
 #define QMP_ACCEPT_UNKNOWNS 1
 
 /* Protects mon_list, monitor_qapi_event_state, monitor_destroyed.  */
-static QemuMutex monitor_lock;
+QemuMutex monitor_lock;
 static GHashTable *monitor_qapi_event_state;
-static QTAILQ_HEAD(, Monitor) mon_list;
+MonitorList mon_list;
 static bool monitor_destroyed;
 
 /* Protects mon_fdsets */
 static QemuMutex mon_fdsets_lock;
 static QLIST_HEAD(, MonFdset) mon_fdsets;
 
-static int mon_refcount;
+int mon_refcount;
 
 static HMPCommand hmp_cmds[];
 static HMPCommand hmp_info_cmds[];
 
-QmpCommandList qmp_commands, qmp_cap_negotiation_commands;
-
 __thread Monitor *cur_mon;
 
 static void monitor_command_cb(void *opaque, const char *cmdline,
                                void *readline_opaque);
 
 /**
- * Is @mon a QMP monitor?
- */
-static inline bool monitor_is_qmp(const Monitor *mon)
-{
-    return (mon->flags & MONITOR_USE_CONTROL);
-}
-
-/**
  * 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.
@@ -241,28 +215,6 @@ int monitor_read_password(MonitorHMP *mon, ReadLineFunc *readline_func,
     }
 }
 
-static void qmp_request_free(QMPRequest *req)
-{
-    qobject_unref(req->req);
-    error_free(req->err);
-    g_free(req);
-}
-
-/* Caller must hold mon->qmp.qmp_queue_lock */
-static void monitor_qmp_cleanup_req_queue_locked(MonitorQMP *mon)
-{
-    while (!g_queue_is_empty(mon->qmp_requests)) {
-        qmp_request_free(g_queue_pop_head(mon->qmp_requests));
-    }
-}
-
-static void monitor_qmp_cleanup_queues(MonitorQMP *mon)
-{
-    qemu_mutex_lock(&mon->qmp_queue_lock);
-    monitor_qmp_cleanup_req_queue_locked(mon);
-    qemu_mutex_unlock(&mon->qmp_queue_lock);
-}
-
 
 static void monitor_flush_locked(Monitor *mon);
 
@@ -322,7 +274,7 @@ void monitor_flush(Monitor *mon)
 }
 
 /* flush at every end of line */
-static int monitor_puts(Monitor *mon, const char *str)
+int monitor_puts(Monitor *mon, const char *str)
 {
     int i;
     char c;
@@ -372,21 +324,6 @@ int monitor_printf(Monitor *mon, const char *fmt, ...)
     return ret;
 }
 
-static void qmp_send_response(MonitorQMP *mon, const QDict *rsp)
-{
-    const QObject *data = QOBJECT(rsp);
-    QString *json;
-
-    json = mon->common.flags & MONITOR_USE_PRETTY ?
-           qobject_to_json_pretty(data) : qobject_to_json(data);
-    assert(json != NULL);
-
-    qstring_append_chr(json, '\n');
-    monitor_puts(&mon->common, qstring_get_str(json));
-
-    qobject_unref(json);
-}
-
 static MonitorQAPIEventConf monitor_qapi_event_conf[QAPI_EVENT__MAX] = {
     /* Limit guest-triggerable events to 1 per second */
     [QAPI_EVENT_RTC_CHANGE]        = { 1000 * SCALE_MS },
@@ -601,8 +538,8 @@ static void handle_hmp_command(MonitorHMP *mon, const char *cmdline);
 
 static void monitor_iothread_init(void);
 
-static void monitor_data_init(Monitor *mon, int flags, bool skip_flush,
-                              bool use_io_thread)
+void monitor_data_init(Monitor *mon, int flags, bool skip_flush,
+                       bool use_io_thread)
 {
     if (use_io_thread && !mon_iothread) {
         monitor_iothread_init();
@@ -614,14 +551,6 @@ static void monitor_data_init(Monitor *mon, int flags, bool skip_flush,
     mon->flags = flags;
 }
 
-static void monitor_data_destroy_qmp(MonitorQMP *mon)
-{
-    json_message_parser_destroy(&mon->parser);
-    qemu_mutex_destroy(&mon->qmp_queue_lock);
-    monitor_qmp_cleanup_req_queue_locked(mon);
-    g_queue_free(mon->qmp_requests);
-}
-
 static void monitor_data_destroy(Monitor *mon)
 {
     g_free(mon->mon_cpu_path);
@@ -1058,18 +987,6 @@ static void monitor_init_qmp_commands(void)
                          qmp_marshal_qmp_capabilities, QCO_ALLOW_PRECONFIG);
 }
 
-static bool qmp_oob_enabled(MonitorQMP *mon)
-{
-    return mon->capab[QMP_CAPABILITY_OOB];
-}
-
-static void monitor_qmp_caps_reset(MonitorQMP *mon)
-{
-    memset(mon->capab_offered, 0, sizeof(mon->capab_offered));
-    memset(mon->capab, 0, sizeof(mon->capab));
-    mon->capab_offered[QMP_CAPABILITY_OOB] = mon->common.use_io_thread;
-}
-
 /*
  * Accept QMP capabilities in @list for @mon.
  * On success, set mon->qmp.capab[], and return true.
@@ -2245,7 +2162,7 @@ static void monitor_fdset_cleanup(MonFdset *mon_fdset)
     }
 }
 
-static void monitor_fdsets_cleanup(void)
+void monitor_fdsets_cleanup(void)
 {
     MonFdset *mon_fdset;
     MonFdset *mon_fdset_next;
@@ -4023,209 +3940,13 @@ cleanup:
     free_cmdline_args(args, nb_args);
 }
 
-static int monitor_can_read(void *opaque)
+int monitor_can_read(void *opaque)
 {
     Monitor *mon = opaque;
 
     return !atomic_mb_read(&mon->suspend_cnt);
 }
 
-/*
- * Emit QMP response @rsp with ID @id to @mon.
- * Null @rsp can only happen for commands with QCO_NO_SUCCESS_RESP.
- * Nothing is emitted then.
- */
-static void monitor_qmp_respond(MonitorQMP *mon, QDict *rsp)
-{
-    if (rsp) {
-        qmp_send_response(mon, rsp);
-    }
-}
-
-static void monitor_qmp_dispatch(MonitorQMP *mon, QObject *req)
-{
-    Monitor *old_mon;
-    QDict *rsp;
-    QDict *error;
-
-    old_mon = cur_mon;
-    cur_mon = &mon->common;
-
-    rsp = qmp_dispatch(mon->commands, req, qmp_oob_enabled(mon));
-
-    cur_mon = old_mon;
-
-    if (mon->commands == &qmp_cap_negotiation_commands) {
-        error = qdict_get_qdict(rsp, "error");
-        if (error
-            && !g_strcmp0(qdict_get_try_str(error, "class"),
-                    QapiErrorClass_str(ERROR_CLASS_COMMAND_NOT_FOUND))) {
-            /* Provide a more useful error message */
-            qdict_del(error, "desc");
-            qdict_put_str(error, "desc", "Expecting capabilities negotiation"
-                          " with 'qmp_capabilities'");
-        }
-    }
-
-    monitor_qmp_respond(mon, rsp);
-    qobject_unref(rsp);
-}
-
-/*
- * Pop a QMP request from a monitor request queue.
- * Return the request, or NULL all request queues are empty.
- * We are using round-robin fashion to pop the request, to avoid
- * processing commands only on a very busy monitor.  To achieve that,
- * when we process one request on a specific monitor, we put that
- * monitor to the end of mon_list queue.
- *
- * Note: if the function returned with non-NULL, then the caller will
- * be with qmp_mon->qmp_queue_lock held, and the caller is responsible
- * to release it.
- */
-static QMPRequest *monitor_qmp_requests_pop_any_with_lock(void)
-{
-    QMPRequest *req_obj = NULL;
-    Monitor *mon;
-    MonitorQMP *qmp_mon;
-
-    qemu_mutex_lock(&monitor_lock);
-
-    QTAILQ_FOREACH(mon, &mon_list, entry) {
-        if (!monitor_is_qmp(mon)) {
-            continue;
-        }
-
-        qmp_mon = container_of(mon, MonitorQMP, common);
-        qemu_mutex_lock(&qmp_mon->qmp_queue_lock);
-        req_obj = g_queue_pop_head(qmp_mon->qmp_requests);
-        if (req_obj) {
-            /* With the lock of corresponding queue held */
-            break;
-        }
-        qemu_mutex_unlock(&qmp_mon->qmp_queue_lock);
-    }
-
-    if (req_obj) {
-        /*
-         * We found one request on the monitor. Degrade this monitor's
-         * priority to lowest by re-inserting it to end of queue.
-         */
-        QTAILQ_REMOVE(&mon_list, mon, entry);
-        QTAILQ_INSERT_TAIL(&mon_list, mon, entry);
-    }
-
-    qemu_mutex_unlock(&monitor_lock);
-
-    return req_obj;
-}
-
-static void monitor_qmp_bh_dispatcher(void *data)
-{
-    QMPRequest *req_obj = monitor_qmp_requests_pop_any_with_lock();
-    QDict *rsp;
-    bool need_resume;
-    MonitorQMP *mon;
-
-    if (!req_obj) {
-        return;
-    }
-
-    mon = req_obj->mon;
-    /*  qmp_oob_enabled() might change after "qmp_capabilities" */
-    need_resume = !qmp_oob_enabled(mon) ||
-        mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1;
-    qemu_mutex_unlock(&mon->qmp_queue_lock);
-    if (req_obj->req) {
-        QDict *qdict = qobject_to(QDict, req_obj->req);
-        QObject *id = qdict ? qdict_get(qdict, "id") : NULL;
-        trace_monitor_qmp_cmd_in_band(qobject_get_try_str(id) ?: "");
-        monitor_qmp_dispatch(mon, req_obj->req);
-    } else {
-        assert(req_obj->err);
-        rsp = qmp_error_response(req_obj->err);
-        req_obj->err = NULL;
-        monitor_qmp_respond(mon, rsp);
-        qobject_unref(rsp);
-    }
-
-    if (need_resume) {
-        /* Pairs with the monitor_suspend() in handle_qmp_command() */
-        monitor_resume(&mon->common);
-    }
-    qmp_request_free(req_obj);
-
-    /* Reschedule instead of looping so the main loop stays responsive */
-    qemu_bh_schedule(qmp_dispatcher_bh);
-}
-
-static void handle_qmp_command(void *opaque, QObject *req, Error *err)
-{
-    MonitorQMP *mon = opaque;
-    QObject *id = NULL;
-    QDict *qdict;
-    QMPRequest *req_obj;
-
-    assert(!req != !err);
-
-    qdict = qobject_to(QDict, req);
-    if (qdict) {
-        id = qdict_get(qdict, "id");
-    } /* else will fail qmp_dispatch() */
-
-    if (req && trace_event_get_state_backends(TRACE_HANDLE_QMP_COMMAND)) {
-        QString *req_json = qobject_to_json(req);
-        trace_handle_qmp_command(mon, qstring_get_str(req_json));
-        qobject_unref(req_json);
-    }
-
-    if (qdict && qmp_is_oob(qdict)) {
-        /* OOB commands are executed immediately */
-        trace_monitor_qmp_cmd_out_of_band(qobject_get_try_str(id) ?: "");
-        monitor_qmp_dispatch(mon, req);
-        qobject_unref(req);
-        return;
-    }
-
-    req_obj = g_new0(QMPRequest, 1);
-    req_obj->mon = mon;
-    req_obj->req = req;
-    req_obj->err = err;
-
-    /* Protect qmp_requests and fetching its length. */
-    qemu_mutex_lock(&mon->qmp_queue_lock);
-
-    /*
-     * Suspend the monitor when we can't queue more requests after
-     * this one.  Dequeuing in monitor_qmp_bh_dispatcher() will resume
-     * it.  Note that when OOB is disabled, we queue at most one
-     * command, for backward compatibility.
-     */
-    if (!qmp_oob_enabled(mon) ||
-        mon->qmp_requests->length == QMP_REQ_QUEUE_LEN_MAX - 1) {
-        monitor_suspend(&mon->common);
-    }
-
-    /*
-     * Put the request to the end of queue so that requests will be
-     * handled in time order.  Ownership for req_obj, req,
-     * etc. will be delivered to the handler side.
-     */
-    assert(mon->qmp_requests->length < QMP_REQ_QUEUE_LEN_MAX);
-    g_queue_push_tail(mon->qmp_requests, req_obj);
-    qemu_mutex_unlock(&mon->qmp_queue_lock);
-
-    /* Kick the dispatcher routine */
-    qemu_bh_schedule(qmp_dispatcher_bh);
-}
-
-static void monitor_qmp_read(void *opaque, const uint8_t *buf, int size)
-{
-    MonitorQMP *mon = opaque;
-
-    json_message_parser_feed(&mon->parser, (const char *) buf, size);
-}
-
 static void monitor_read(void *opaque, const uint8_t *buf, int size)
 {
     MonitorHMP *mon;
@@ -4312,56 +4033,6 @@ void monitor_resume(Monitor *mon)
     trace_monitor_suspend(mon, -1);
 }
 
-static QDict *qmp_greeting(MonitorQMP *mon)
-{
-    QList *cap_list = qlist_new();
-    QObject *ver = NULL;
-    QMPCapability cap;
-
-    qmp_marshal_query_version(NULL, &ver, NULL);
-
-    for (cap = 0; cap < QMP_CAPABILITY__MAX; cap++) {
-        if (mon->capab_offered[cap]) {
-            qlist_append_str(cap_list, QMPCapability_str(cap));
-        }
-    }
-
-    return qdict_from_jsonf_nofail(
-        "{'QMP': {'version': %p, 'capabilities': %p}}",
-        ver, cap_list);
-}
-
-static void monitor_qmp_event(void *opaque, int event)
-{
-    QDict *data;
-    MonitorQMP *mon = opaque;
-
-    switch (event) {
-    case CHR_EVENT_OPENED:
-        mon->commands = &qmp_cap_negotiation_commands;
-        monitor_qmp_caps_reset(mon);
-        data = qmp_greeting(mon);
-        qmp_send_response(mon, data);
-        qobject_unref(data);
-        mon_refcount++;
-        break;
-    case CHR_EVENT_CLOSED:
-        /*
-         * Note: this is only useful when the output of the chardev
-         * backend is still open.  For example, when the backend is
-         * stdio, it's possible that stdout is still open when stdin
-         * is closed.
-         */
-        monitor_qmp_cleanup_queues(mon);
-        json_message_parser_destroy(&mon->parser);
-        json_message_parser_init(&mon->parser, handle_qmp_command,
-                                 mon, NULL);
-        mon_refcount--;
-        monitor_fdsets_cleanup();
-        break;
-    }
-}
-
 static void monitor_event(void *opaque, int event)
 {
     Monitor *mon = opaque;
@@ -4495,7 +4166,7 @@ int error_vprintf_unless_qmp(const char *fmt, va_list ap)
     return -1;
 }
 
-static void monitor_list_append(Monitor *mon)
+void monitor_list_append(Monitor *mon)
 {
     qemu_mutex_lock(&monitor_lock);
     /*
@@ -4515,60 +4186,6 @@ static void monitor_list_append(Monitor *mon)
     }
 }
 
-static void monitor_qmp_setup_handlers_bh(void *opaque)
-{
-    MonitorQMP *mon = opaque;
-    GMainContext *context;
-
-    assert(mon->common.use_io_thread);
-    context = iothread_get_g_main_context(mon_iothread);
-    assert(context);
-    qemu_chr_fe_set_handlers(&mon->common.chr, monitor_can_read,
-                             monitor_qmp_read, monitor_qmp_event,
-                             NULL, &mon->common, context, true);
-    monitor_list_append(&mon->common);
-}
-
-static void monitor_init_qmp(Chardev *chr, int flags)
-{
-    MonitorQMP *mon = g_new0(MonitorQMP, 1);
-
-    /* Only HMP supports readline */
-    assert(!(flags & MONITOR_USE_READLINE));
-
-    /* Note: we run QMP monitor in I/O thread when @chr supports that */
-    monitor_data_init(&mon->common, flags, false,
-                      qemu_chr_has_feature(chr, QEMU_CHAR_FEATURE_GCONTEXT));
-
-    qemu_mutex_init(&mon->qmp_queue_lock);
-    mon->qmp_requests = g_queue_new();
-
-    qemu_chr_fe_init(&mon->common.chr, chr, &error_abort);
-    qemu_chr_fe_set_echo(&mon->common.chr, true);
-
-    json_message_parser_init(&mon->parser, handle_qmp_command, mon, NULL);
-    if (mon->common.use_io_thread) {
-        /*
-         * Make sure the old iowatch is gone.  It's possible when
-         * e.g. the chardev is in client mode, with wait=on.
-         */
-        remove_fd_in_watch(chr);
-        /*
-         * We can't call qemu_chr_fe_set_handlers() directly here
-         * since chardev might be running in the monitor I/O
-         * thread.  Schedule a bottom half.
-         */
-        aio_bh_schedule_oneshot(iothread_get_aio_context(mon_iothread),
-                                monitor_qmp_setup_handlers_bh, mon);
-        /* The bottom half will add @mon to @mon_list */
-    } else {
-        qemu_chr_fe_set_handlers(&mon->common.chr, monitor_can_read,
-                                 monitor_qmp_read, monitor_qmp_event,
-                                 NULL, &mon->common, NULL, true);
-        monitor_list_append(&mon->common);
-    }
-}
-
 static void monitor_init_hmp(Chardev *chr, int flags)
 {
     MonitorHMP *mon = g_new0(MonitorHMP, 1);