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[Qemu-devel] [PULL 05/26] qmp: Clean up how we enforce capability negoti
From: |
Markus Armbruster |
Subject: |
[Qemu-devel] [PULL 05/26] qmp: Clean up how we enforce capability negotiation |
Date: |
Tue, 28 Feb 2017 20:06:15 +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 without all the other commands, by
registering only qmp_qmp_capabilities(). Register the others 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>
Reviewed-by: Eric Blake <address@hidden>
Message-Id: <address@hidden>
---
monitor.c | 70 ++++++++++++++++++++++++++++++++++++---------------------------
1 file changed, 40 insertions(+), 30 deletions(-)
diff --git a/monitor.c b/monitor.c
index 1cc2274..e522b6f 100644
--- a/monitor.c
+++ b/monitor.c
@@ -563,11 +563,6 @@ 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)
@@ -995,7 +990,7 @@ static void qmp_unregister_commands_hack(void)
#endif
}
-void monitor_init_qmp_commands(void)
+static void monitor_init_real_qmp_commands(void)
{
qmp_init_marshal();
@@ -1009,6 +1004,32 @@ void monitor_init_qmp_commands(void)
qmp_unregister_commands_hack();
}
+void monitor_init_qmp_commands(void)
+{
+ /*
+ * Start with just qmp_capabilities, to enforce capability
+ * negotiation. qmp_capabilities will register the other
+ * commands. See also the error message replacement hack in
+ * handle_qmp_command().
+ */
+ qmp_register_command("qmp_capabilities",
+ qmp_marshal_qmp_capabilities, QCO_NO_OPTIONS);
+}
+
+void qmp_qmp_capabilities(Error **errp)
+{
+ if (cur_mon->qmp.in_command_mode) {
+ error_set(errp, ERROR_CLASS_COMMAND_NOT_FOUND,
+ "Capabilities negotiation is already complete, command "
+ "ignored");
+ return;
+ }
+
+ cur_mon->qmp.in_command_mode = true;
+ qmp_unregister_command("qmp_capabilities");
+ monitor_init_real_qmp_commands();
+}
+
/* set the current CPU defined by the user */
int monitor_set_cpu(int cpu_index)
{
@@ -3676,26 +3697,6 @@ 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
*
@@ -3781,12 +3782,21 @@ 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(req);
+ qdict = qdict_get_qdict(qobject_to_qdict(rsp), "error");
+ if (qdict) {
+ if (!mon->qmp.in_command_mode
+ && !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) {
qdict = qdict_new();
--
2.7.4
- [Qemu-devel] [PULL 00/26] QAPI patches for 2017-02-28, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 03/26] qmp-test: New, covering basic QMP protocol, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 04/26] qmp: Dumb down how we run QMP command registration, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 11/26] qapi: Make QObject input visitor set *list reliably, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 06/26] qmp: Drop duplicated QMP command object checks, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 01/26] qga: Fix crash on non-dictionary QMP argument, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 07/26] qmp: Eliminate silly QERR_QMP_* macros, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 09/26] qapi: Improve a QObject input visitor error message, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 05/26] qmp: Clean up how we enforce capability negotiation,
Markus Armbruster <=
- [Qemu-devel] [PULL 13/26] qapi: Drop string input visitor method optional(), Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 25/26] qapi: Fix object input visit beyond end of list, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 22/26] test-qobject-input-visitor: Cover missing nested struct member, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 19/26] test-string-input-visitor: Tear down existing test automatically, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 15/26] qom: Make object_property_set_qobject()'s input visitor strict, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 20/26] test-string-input-visitor: Improve list coverage, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 26/26] qapi: Improve qobject visitor documentation, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 18/26] tests-qobject-input-strict: Merge into test-qobject-input-visitor, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 23/26] qapi: Make input visitors detect unvisited list tails, Markus Armbruster, 2017/02/28
- [Qemu-devel] [PULL 02/26] libqtest: Work around a "QMP wants a newline" bug, Markus Armbruster, 2017/02/28