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[Qemu-devel] [PULL 29/36] qmp: support out-of-band (oob) execution
From: |
Eric Blake |
Subject: |
[Qemu-devel] [PULL 29/36] qmp: support out-of-band (oob) execution |
Date: |
Mon, 12 Mar 2018 13:36:20 -0500 |
From: Peter Xu <address@hidden>
Having "allow-oob":true for a command does not mean that this command
will always be run in out-of-band mode. The out-of-band quick path will
only be executed if we specify the extra "run-oob" flag when sending the
QMP request:
{ "execute": "command-that-allows-oob",
"arguments": { ... },
"control": { "run-oob": true } }
The "control" key is introduced to store this extra flag. "control"
field is used to store arguments that are shared by all the commands,
rather than command specific arguments. Let "run-oob" be the first.
Note that in the patch I exported qmp_dispatch_check_obj() to be used to
check the request earlier, and at the same time allowed "id" field to be
there since actually we always allow that.
Reviewed-by: Stefan Hajnoczi <address@hidden>
Signed-off-by: Peter Xu <address@hidden>
Message-Id: <address@hidden>
Reviewed-by: Eric Blake <address@hidden>
[eblake: rebase to qobject_to(), spelling fix]
Signed-off-by: Eric Blake <address@hidden>
---
include/qapi/qmp/dispatch.h | 2 ++
monitor.c | 84 ++++++++++++++++++++++++++++++++++++++++-----
qapi/qmp-dispatch.c | 33 +++++++++++++++++-
trace-events | 2 ++
4 files changed, 111 insertions(+), 10 deletions(-)
diff --git a/include/qapi/qmp/dispatch.h b/include/qapi/qmp/dispatch.h
index 26eb13ff417..ffb4652f716 100644
--- a/include/qapi/qmp/dispatch.h
+++ b/include/qapi/qmp/dispatch.h
@@ -48,6 +48,8 @@ bool qmp_command_is_enabled(const QmpCommand *cmd);
const char *qmp_command_name(const QmpCommand *cmd);
bool qmp_has_success_response(const QmpCommand *cmd);
QObject *qmp_build_error_object(Error *err);
+QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp);
+bool qmp_is_oob(QDict *dict);
typedef void (*qmp_cmd_callback_fn)(QmpCommand *cmd, void *opaque);
diff --git a/monitor.c b/monitor.c
index d28457d60d7..3b7a4a5c3a7 100644
--- a/monitor.c
+++ b/monitor.c
@@ -1110,6 +1110,44 @@ static void qmp_caps_apply(Monitor *mon,
QMPCapabilityList *list)
}
}
+/*
+ * Return true if check successful, or false otherwise. When false is
+ * returned, detailed error will be in errp if provided.
+ */
+static bool qmp_cmd_oob_check(Monitor *mon, QDict *req, Error **errp)
+{
+ const char *command;
+ QmpCommand *cmd;
+
+ command = qdict_get_try_str(req, "execute");
+ if (!command) {
+ error_setg(errp, "Command field 'execute' missing");
+ return false;
+ }
+
+ cmd = qmp_find_command(mon->qmp.commands, command);
+ if (!cmd) {
+ error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
+ "The command %s has not been found", command);
+ return false;
+ }
+
+ if (qmp_is_oob(req)) {
+ if (!qmp_oob_enabled(mon)) {
+ error_setg(errp, "Please enable Out-Of-Band first "
+ "for the session during capabilities negotiation");
+ return false;
+ }
+ if (!(cmd->options & QCO_ALLOW_OOB)) {
+ error_setg(errp, "The command %s does not support OOB",
+ command);
+ return false;
+ }
+ }
+
+ return true;
+}
+
void qmp_qmp_capabilities(bool has_enable, QMPCapabilityList *enable,
Error **errp)
{
@@ -4001,6 +4039,7 @@ static void monitor_qmp_bh_dispatcher(void *data)
QMPRequest *req_obj = monitor_qmp_requests_pop_one();
if (req_obj) {
+ trace_monitor_qmp_cmd_in_band(qobject_get_try_str(req_obj->id) ?: "");
monitor_qmp_dispatch_one(req_obj);
/* Reschedule instead of looping so the main loop stays responsive */
qemu_bh_schedule(mon_global.qmp_dispatcher_bh);
@@ -4024,17 +4063,31 @@ static void handle_qmp_command(JSONMessageParser
*parser, GQueue *tokens)
error_setg(&err, QERR_JSON_PARSING);
}
if (err) {
- monitor_qmp_respond(mon, NULL, err, NULL);
- qobject_decref(req);
- return;
+ goto err;
}
- qdict = qobject_to(QDict, req);
- if (qdict) {
- id = qdict_get(qdict, "id");
- qobject_incref(id);
- qdict_del(qdict, "id");
- } /* else will fail qmp_dispatch() */
+ /* Check against the request in general layout */
+ qdict = qmp_dispatch_check_obj(req, &err);
+ if (!qdict) {
+ goto err;
+ }
+
+ /* Check against OOB specific */
+ if (!qmp_cmd_oob_check(mon, qdict, &err)) {
+ goto err;
+ }
+
+ id = qdict_get(qdict, "id");
+
+ /* When OOB is enabled, the "id" field is mandatory. */
+ if (qmp_oob_enabled(mon) && !id) {
+ error_setg(&err, "Out-Of-Band capability requires that "
+ "every command contains an 'id' field");
+ goto err;
+ }
+
+ qobject_incref(id);
+ qdict_del(qdict, "id");
req_obj = g_new0(QMPRequest, 1);
req_obj->mon = mon;
@@ -4042,6 +4095,14 @@ static void handle_qmp_command(JSONMessageParser
*parser, GQueue *tokens)
req_obj->req = req;
req_obj->need_resume = false;
+ if (qmp_is_oob(qdict)) {
+ /* Out-Of-Band (OOB) requests are executed directly in parser. */
+ trace_monitor_qmp_cmd_out_of_band(qobject_get_try_str(req_obj->id)
+ ?: "");
+ monitor_qmp_dispatch_one(req_obj);
+ return;
+ }
+
/* Protect qmp_requests and fetching its length. */
qemu_mutex_lock(&mon->qmp.qmp_queue_lock);
@@ -4078,6 +4139,11 @@ static void handle_qmp_command(JSONMessageParser
*parser, GQueue *tokens)
/* Kick the dispatcher routine */
qemu_bh_schedule(mon_global.qmp_dispatcher_bh);
+ return;
+
+err:
+ monitor_qmp_respond(mon, NULL, err, NULL);
+ qobject_decref(req);
}
static void monitor_qmp_read(void *opaque, const uint8_t *buf, int size)
diff --git a/qapi/qmp-dispatch.c b/qapi/qmp-dispatch.c
index af537f3d7d2..dd059072651 100644
--- a/qapi/qmp-dispatch.c
+++ b/qapi/qmp-dispatch.c
@@ -17,8 +17,9 @@
#include "qapi/qmp/json-parser.h"
#include "qapi/qmp/qdict.h"
#include "qapi/qmp/qjson.h"
+#include "qapi/qmp/qbool.h"
-static QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
+QDict *qmp_dispatch_check_obj(const QObject *request, Error **errp)
{
const QDictEntry *ent;
const char *arg_name;
@@ -50,6 +51,14 @@ static QDict *qmp_dispatch_check_obj(const QObject *request,
Error **errp)
"QMP input member 'arguments' must be an object");
return NULL;
}
+ } else if (!strcmp(arg_name, "id")) {
+ continue;
+ } else if (!strcmp(arg_name, "control")) {
+ if (qobject_type(arg_obj) != QTYPE_QDICT) {
+ error_setg(errp,
+ "QMP input member 'control' must be a dict");
+ return NULL;
+ }
} else {
error_setg(errp, "QMP input member '%s' is unexpected",
arg_name);
@@ -120,6 +129,28 @@ QObject *qmp_build_error_object(Error *err)
error_get_pretty(err));
}
+/*
+ * Detect whether a request should be run out-of-band, by quickly
+ * peeking at whether we have: { "control": { "run-oob": true } }. By
+ * default commands are run in-band.
+ */
+bool qmp_is_oob(QDict *dict)
+{
+ QBool *bool_obj;
+
+ dict = qdict_get_qdict(dict, "control");
+ if (!dict) {
+ return false;
+ }
+
+ bool_obj = qobject_to(QBool, qdict_get(dict, "run-oob"));
+ if (!bool_obj) {
+ return false;
+ }
+
+ return qbool_get_bool(bool_obj);
+}
+
QObject *qmp_dispatch(QmpCommandList *cmds, QObject *request)
{
Error *err = NULL;
diff --git a/trace-events b/trace-events
index fe10c3b487c..bd036da278d 100644
--- a/trace-events
+++ b/trace-events
@@ -48,6 +48,8 @@ monitor_protocol_event_queue(uint32_t event, void *qdict,
uint64_t rate) "event=
handle_hmp_command(void *mon, const char *cmdline) "mon %p cmdline: %s"
handle_qmp_command(void *mon, const char *req) "mon %p req: %s"
monitor_suspend(void *ptr, int cnt) "mon %p: %d"
+monitor_qmp_cmd_in_band(const char *id) "%s"
+monitor_qmp_cmd_out_of_band(const char *id) "%s"
# dma-helpers.c
dma_blk_io(void *dbs, void *bs, int64_t offset, bool to_dev) "dbs=%p bs=%p
offset=%" PRId64 " to_dev=%d"
--
2.14.3
- [Qemu-devel] [PULL 10/36] block: Handle null backing link, (continued)
- [Qemu-devel] [PULL 10/36] block: Handle null backing link, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 13/36] qobject: introduce qstring_get_try_str(), Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 26/36] qmp: add new event "command-dropped", Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 19/36] monitor: let mon_list be tail queue, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 01/36] qapi2texi: minor python code simplification, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 12/36] docs: update QMP documents for OOB commands, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 14/36] qobject: introduce qobject_get_try_str(), Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 22/36] monitor: introduce monitor_qmp_respond(), Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 20/36] monitor: allow using IO thread for parsing, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 24/36] monitor: let suspend/resume work even with QMPs, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 29/36] qmp: support out-of-band (oob) execution,
Eric Blake <=
- [Qemu-devel] [PULL 32/36] qmp: add command "x-oob-test", Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 34/36] tests: qmp-test: add oob test, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 28/36] qapi: introduce new cmd option "allow-oob", Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 21/36] qmp: introduce QMPCapability, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 30/36] qmp: isolate responses into io thread, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 15/36] qobject: let object_property_get_str() use new API, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 23/36] monitor: let suspend_cnt be thread safe, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 27/36] monitor: send event when command queue full, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 25/36] monitor: separate QMP parser and dispatcher, Eric Blake, 2018/03/12
- [Qemu-devel] [PULL 31/36] monitor: enable IO thread for (qmp & !mux) typed, Eric Blake, 2018/03/12