[Qemu-devel] [PATCH 6/9] log: log QMP commands and replies

["Denis V. Lunev" <den@openvz.org>]

From: Pavel Butsykin <pbutsykin@virtuozzo.com>

This log would be very welcome for long-term diagnostics of the system
in the production. This log is at least necessary to understand what
has been happened on the system and to identify issues at higher-level
subsystems (libvirt, etc).

These messages will be quite useful to understand how things are going.

Signed-off-by: Pavel Butsykin <pbutsykin@virtuozzo.com>
Signed-off-by: Denis V. Lunev <den@openvz.org>
CC: Stefan Hajnoczi <stefanha@redhat.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Luiz Capitulino <lcapitulino@redhat.com>
CC: Markus Armbruster <armbru@redhat.com>
CC: Eric Blake <eblake@redhat.com>
---
 include/qemu/log.h |  1 +
 monitor.c          | 13 +++++++++++++
 util/log.c         |  2 ++
 3 files changed, 16 insertions(+)

diff --git a/include/qemu/log.h b/include/qemu/log.h
index a05c7dc..55bceae 100644
--- a/include/qemu/log.h
+++ b/include/qemu/log.h
@@ -42,6 +42,7 @@ static inline bool qemu_log_separate(void)
 #define CPU_LOG_TB_NOCHAIN (1 << 13)
 #define CPU_LOG_PAGE       (1 << 14)
 #define LOG_TRACE          (1 << 15)
+#define LOG_QMP            (1 << 16)
 
 /* Returns true if a bit is set in the current loglevel mask
  */
diff --git a/monitor.c b/monitor.c
index e99ca8c..eec4e58 100644
--- a/monitor.c
+++ b/monitor.c
@@ -437,6 +437,12 @@ static void monitor_protocol_emitter(Monitor *mon, QObject *data,
     }
 
     monitor_json_emitter(mon, QOBJECT(qmp));
+    if (qemu_loglevel_mask(LOG_QMP)) {
+        QString *output_json = qobject_to_json(QOBJECT(qmp));
+        qemu_log_mask(LOG_QMP, "QMP reply: %s\n", output_json->string);
+        QDECREF(output_json);
+    }
+
     QDECREF(qmp);
 }
 
@@ -3867,6 +3873,11 @@ static void handle_qmp_command(JSONMessageParser *parser, GQueue *tokens)
         goto err_out;
     }
 
+    if (qemu_loglevel_mask(LOG_QMP)) {
+        QString *output_json = qobject_to_json(obj);
+        qemu_log_mask(LOG_QMP, "QMP command: %s\n", output_json->string);
+        QDECREF(output_json);
+    }
     input = qmp_check_input_obj(obj, &local_err);
     if (!input) {
         qobject_decref(obj);
@@ -3988,12 +3999,14 @@ static void monitor_qmp_event(void *opaque, int event)
         monitor_json_emitter(mon, data);
         qobject_decref(data);
         mon_refcount++;
+        qemu_log_mask(LOG_QMP, "QMP: new connection established\n");
         break;
     case CHR_EVENT_CLOSED:
         json_message_parser_destroy(&mon->qmp.parser);
         json_message_parser_init(&mon->qmp.parser, handle_qmp_command);
         mon_refcount--;
         monitor_fdsets_cleanup();
+        qemu_log_mask(LOG_QMP, "QMP: connection closed\n");
         break;
     }
 }
diff --git a/util/log.c b/util/log.c
index 65d46e2..5fc517b 100644
--- a/util/log.c
+++ b/util/log.c
@@ -131,6 +131,8 @@ const QEMULogItem qemu_log_items[] = {
     { CPU_LOG_TB_NOCHAIN, "nochain",
       "do not chain compiled TBs so that \"exec\" and \"cpu\" show\n"
       "complete traces" },
+    { LOG_QMP, "qmp",
+      "log the QMP commands and events" },
     { 0, NULL, NULL },
 };
 
-- 
2.5.0