[Qemu-devel] [PATCH 2/2] QMP: Require 'use_unstable' arg for capabilities negotiation

[Luiz Capitulino]

This helps ensuring two things:

1. An initial warning on client writers playing with current QMP
2. Clients using unstable QMP will break when we declare QMP stable and
   drop that argument

Signed-off-by: Luiz Capitulino <address@hidden>
---
 QMP/README      |    2 +-
 QMP/qmp-shell   |    2 +-
 QMP/qmp.py      |    3 +++
 monitor.c       |    7 ++++++-
 qemu-monitor.hx |   14 ++++++++++----
 5 files changed, 21 insertions(+), 7 deletions(-)

diff --git a/QMP/README b/QMP/README
index 30a283b..14d36ee 100644
--- a/QMP/README
+++ b/QMP/README
@@ -65,7 +65,7 @@ Trying 127.0.0.1...
 Connected to localhost.
 Escape character is '^]'.
 {"QMP": {"version": {"qemu": "0.12.50", "package": ""}, "capabilities": []}}
-{ "execute": "qmp_capabilities" }
+{ "execute": "qmp_capabilities", "arguments": { "use_unstable": true } }
 {"return": {}}
 { "execute": "query-version" }
 {"return": {"qemu": "0.12.50", "package": ""}}
diff --git a/QMP/qmp-shell b/QMP/qmp-shell
index a5b72d1..17033b1 100755
--- a/QMP/qmp-shell
+++ b/QMP/qmp-shell
@@ -42,7 +42,7 @@ def main():
 
     qemu = qmp.QEMUMonitorProtocol(argv[1])
     qemu.connect()
-    qemu.send("qmp_capabilities")
+    qemu.capabilities()
 
     print 'Connected!'
 
diff --git a/QMP/qmp.py b/QMP/qmp.py
index 4062f84..9d6f428 100644
--- a/QMP/qmp.py
+++ b/QMP/qmp.py
@@ -26,6 +26,9 @@ class QEMUMonitorProtocol:
             raise QMPConnectError
         return data['QMP']['capabilities']
 
+    def capabilities(self):
+        self.send_raw('{ "execute": "qmp_capabilities", "arguments": { 
"use_unstable": true } }')
+
     def close(self):
         self.sock.close()
 
diff --git a/monitor.c b/monitor.c
index 55633fd..19ddf1e 100644
--- a/monitor.c
+++ b/monitor.c
@@ -479,7 +479,12 @@ static int do_qmp_capabilities(Monitor *mon, const QDict 
*params,
 {
     /* Will setup QMP capabilities in the future */
     if (monitor_ctrl_mode(mon)) {
-        mon->mc->command_mode = 1;
+        if (qdict_get_bool(params, "use_unstable")) {
+            mon->mc->command_mode = 1;
+        } else {
+            qerror_report(QERR_INVALID_PARAMETER, "use_unstable");
+            return -1;
+        }
     }
 
     return 0;
diff --git a/qemu-monitor.hx b/qemu-monitor.hx
index 2d2a09e..a56e1f5 100644
--- a/qemu-monitor.hx
+++ b/qemu-monitor.hx
@@ -1557,7 +1557,7 @@ EQMP
 
     {
         .name       = "qmp_capabilities",
-        .args_type  = "",
+        .args_type  = "use_unstable:b",
         .params     = "",
         .help       = "enable QMP capabilities",
         .user_print = monitor_user_noop,
@@ -1575,14 +1575,20 @@ qmp_capabilities
 
 Enable QMP capabilities.
 
-Arguments: None.
+Arguments:
+
+- use_unstable: really enable unstable version of QMP (json-bool)
 
 Example:
 
--> { "execute": "qmp_capabilities" }
+-> { "execute": "qmp_capabilities", "arguments": { "use_unstable": true } }
 <- { "return": {} }
 
-Note: This command must be issued before issuing any other command.
+Notes:
+
+(1) This command must be issued before issuing any other command.
+
+(2) Setting "use_unstable" to true is the only way to get anything working.
 
 EQMP
 
-- 
1.7.2.rc0