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[Qemu-devel] [PATCH v4 07/28] qmp: Clean up how we enforce capability ne
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PATCH v4 07/28] qmp: Clean up how we enforce capability negotiation |
Date: |
Fri, 3 Mar 2017 13:32:27 +0100 |
To enforce capability negotiation before normal operation,
handle_qmp_command() inspects every command before it's handed off to
qmp_dispatch(). This is a bit of a layering violation, and results in
duplicated code.
Before capability negotiation (!cur_mon->in_command_mode), we fail
commands other than "qmp_capabilities". This is what enforces
capability negotiation.
Afterwards, we fail command "qmp_capabilities".
Clean this up as follows.
The obvious place to fail a command is the command itself, so move the
"afterwards" check to qmp_qmp_capabilities().
We do the "before" check in every other command, but that would be
bothersome. Instead, start with an alternate list of commant that
contains only "qmp_capabilities". Switch to the full list in
qmp_qmp_capabilities().
Additionally, replace the generic human-readable error message for
CommandNotFound by one that reminds the user to run qmp_capabilities.
Without that, we'd regress commit 2d5a834.
Signed-off-by: Markus Armbruster <address@hidden>
---
monitor.c | 76 +++++++++++++++++++++++++++++++++++----------------------------
1 file changed, 42 insertions(+), 34 deletions(-)
diff --git a/monitor.c b/monitor.c
index c7f7602..b540096 100644
--- a/monitor.c
+++ b/monitor.c
@@ -165,7 +165,7 @@ typedef struct {
* When command qmp_capabilities succeeds, we go into command
* mode.
*/
- bool in_command_mode; /* are we in command mode? */
+ QmpCommandList *commands;
} MonitorQMP;
/*
@@ -221,7 +221,7 @@ static int mon_refcount;
static mon_cmd_t mon_cmds[];
static mon_cmd_t info_cmds[];
-QmpCommandList qmp_commands;
+QmpCommandList qmp_commands, qmp_cap_negotiation_commands;
Monitor *cur_mon;
@@ -416,7 +416,8 @@ static void monitor_qapi_event_emit(QAPIEvent event, QDict
*qdict)
trace_monitor_protocol_event_emit(event, qdict);
QLIST_FOREACH(mon, &mon_list, entry) {
- if (monitor_is_qmp(mon) && mon->qmp.in_command_mode) {
+ if (monitor_is_qmp(mon)
+ && mon->qmp.commands != &qmp_cap_negotiation_commands) {
monitor_json_emitter(mon, QOBJECT(qdict));
}
}
@@ -565,11 +566,6 @@ static void monitor_qapi_event_init(void)
qmp_event_set_func_emit(monitor_qapi_event_queue);
}
-void qmp_qmp_capabilities(Error **errp)
-{
- cur_mon->qmp.in_command_mode = true;
-}
-
static void handle_hmp_command(Monitor *mon, const char *cmdline);
static void monitor_data_init(Monitor *mon)
@@ -921,7 +917,7 @@ CommandInfoList *qmp_query_commands(Error **errp)
{
CommandInfoList *list = NULL;
- qmp_for_each_command(&qmp_commands, query_commands_cb, &list);
+ qmp_for_each_command(cur_mon->qmp.commands, query_commands_cb, &list);
return list;
}
@@ -1001,6 +997,13 @@ static void qmp_unregister_commands_hack(void)
void monitor_init_qmp_commands(void)
{
+ /*
+ * Two command lists:
+ * - qmp_commands contains all QMP commands
+ * - qmp_cap_negotiation_commands contains just
+ * "qmp_capabilities", to enforce capability negotiation
+ */
+
qmp_init_marshal(&qmp_commands);
qmp_register_command(&qmp_commands, "query-qmp-schema",
@@ -1012,6 +1015,22 @@ void monitor_init_qmp_commands(void)
QCO_NO_OPTIONS);
qmp_unregister_commands_hack();
+
+ QTAILQ_INIT(&qmp_cap_negotiation_commands);
+ qmp_register_command(&qmp_cap_negotiation_commands, "qmp_capabilities",
+ qmp_marshal_qmp_capabilities, QCO_NO_OPTIONS);
+}
+
+void qmp_qmp_capabilities(Error **errp)
+{
+ if (cur_mon->qmp.commands == &qmp_commands) {
+ error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
+ "Capabilities negotiation is already complete, command "
+ "ignored");
+ return;
+ }
+
+ cur_mon->qmp.commands = &qmp_commands;
}
/* set the current CPU defined by the user */
@@ -3681,26 +3700,6 @@ static int monitor_can_read(void *opaque)
return (mon->suspend_cnt == 0) ? 1 : 0;
}
-static bool invalid_qmp_mode(const Monitor *mon, const char *cmd,
- Error **errp)
-{
- bool is_cap = g_str_equal(cmd, "qmp_capabilities");
-
- if (is_cap && mon->qmp.in_command_mode) {
- error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
- "Capabilities negotiation is already complete, command "
- "'%s' ignored", cmd);
- return true;
- }
- if (!is_cap && !mon->qmp.in_command_mode) {
- error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
- "Expecting capabilities negotiation with "
- "'qmp_capabilities' before command '%s'", cmd);
- return true;
- }
- return false;
-}
-
/*
* Input object checking rules
*
@@ -3786,11 +3785,20 @@ static void handle_qmp_command(JSONMessageParser
*parser, GQueue *tokens)
cmd_name = qdict_get_str(qdict, "execute");
trace_handle_qmp_command(mon, cmd_name);
- if (invalid_qmp_mode(mon, cmd_name, &err)) {
- goto err_out;
- }
+ rsp = qmp_dispatch(cur_mon->qmp.commands, req);
- rsp = qmp_dispatch(&qmp_commands, req);
+ qdict = qdict_get_qdict(qobject_to_qdict(rsp), "error");
+ if (qdict) {
+ if (mon->qmp.commands == &qmp_cap_negotiation_commands
+ && !g_strcmp0(qdict_get_try_str(qdict, "class"),
+ QapiErrorClass_lookup[ERROR_CLASS_COMMAND_NOT_FOUND])) {
+ /* Provide a more useful error message */
+ qdict_del(qdict, "desc");
+ qdict_put(qdict, "desc",
+ qstring_from_str("Expecting capabilities negotiation"
+ " with 'qmp_capabilities'"));
+ }
+ }
err_out:
if (err) {
@@ -3888,7 +3896,7 @@ static void monitor_qmp_event(void *opaque, int event)
switch (event) {
case CHR_EVENT_OPENED:
- mon->qmp.in_command_mode = false;
+ mon->qmp.commands = &qmp_cap_negotiation_commands;
data = get_qmp_greeting();
monitor_json_emitter(mon, data);
qobject_decref(data);
--
2.7.4
- Re: [Qemu-devel] [PATCH v4 25/28] qapi: Make input visitors detect unvisited list tails, (continued)
- [Qemu-devel] [PATCH v4 24/28] test-qobject-input-visitor: Cover missing nested struct member, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 28/28] qapi: Improve qobject visitor documentation, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 21/28] test-string-input-visitor: Tear down existing test automatically, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 19/28] qapi: Drop unused non-strict qobject input visitor, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 02/28] libqtest: Work around a "QMP wants a newline" bug, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 22/28] test-string-input-visitor: Improve list coverage, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 14/28] qapi: Improve qobject input visitor error reporting, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 20/28] tests-qobject-input-strict: Merge into test-qobject-input-visitor, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 07/28] qmp: Clean up how we enforce capability negotiation,
Markus Armbruster <=
- [Qemu-devel] [PATCH v4 16/28] qapi: Make string input and opts visitor require non-null input, Markus Armbruster, 2017/03/03
- [Qemu-devel] [PATCH v4 05/28] qapi: Support multiple command registries per program, Markus Armbruster, 2017/03/03