[Qemu-devel] [PATCH v3] trace: [qmp] Add QAPI/QMP commands to query and control event tracing state

[Lluís Vilanova]

Also removes old "trace-event", "trace-file" and "info trace-events" HMP
commands.

Signed-off-by: Lluís Vilanova <address@hidden>
---
 monitor.c           |   24 +++++++---------
 qapi-schema.json    |    3 ++
 qapi/trace.json     |   44 +++++++++++++++++++++++++++++
 qmp-commands.hx     |   27 ++++++++++++++++++
 trace/Makefile.objs |    1 +
 trace/control.c     |   13 ---------
 trace/control.h     |    7 -----
 trace/qmp.c         |   77 +++++++++++++++++++++++++++++++++++++++++++++++++++
 8 files changed, 162 insertions(+), 34 deletions(-)
 create mode 100644 qapi/trace.json
 create mode 100644 trace/qmp.c

diff --git a/monitor.c b/monitor.c
index cdbaa60..0f605f5 100644
--- a/monitor.c
+++ b/monitor.c
@@ -887,19 +887,8 @@ static void do_trace_event_set_state(Monitor *mon, const 
QDict *qdict)
     const char *tp_name = qdict_get_str(qdict, "name");
     bool new_state = qdict_get_bool(qdict, "option");
 
-    bool found = false;
-    TraceEvent *ev = NULL;
-    while ((ev = trace_event_pattern(tp_name, ev)) != NULL) {
-        found = true;
-        if (!trace_event_get_state_static(ev)) {
-            monitor_printf(mon, "event \"%s\" is not traceable\n", tp_name);
-        } else {
-            trace_event_set_state_dynamic(ev, new_state);
-        }
-    }
-    if (!trace_event_is_pattern(tp_name) && !found) {
-        monitor_printf(mon, "unknown event name \"%s\"\n", tp_name);
-    }
+    /* TODO: should propagate QMP errors to HMP */
+    qmp_trace_event_set_state(tp_name, new_state, true, true, NULL);
 }
 
 #ifdef CONFIG_TRACE_SIMPLE
@@ -1079,7 +1068,14 @@ static void do_info_cpu_stats(Monitor *mon, const QDict 
*qdict)
 
 static void do_trace_print_events(Monitor *mon, const QDict *qdict)
 {
-    trace_print_events((FILE *)mon, &monitor_fprintf);
+    TraceEventStateList *events = qmp_trace_event_get_state("*", NULL);
+    TraceEventStateList *event;
+    for (event = events; event != NULL; event = event->next) {
+        monitor_printf(mon, "%s : state %u\n",
+                       event->value->name,
+                       event->value->sstatic && event->value->sdynamic);
+    }
+    qapi_free_TraceEventStateList(events);
 }
 
 static int client_migrate_info(Monitor *mon, const QDict *qdict,
diff --git a/qapi-schema.json b/qapi-schema.json
index 341f417..42b90df 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -11,6 +11,9 @@
 # QAPI event definitions
 { 'include': 'qapi/event.json' }
 
+# Tracing commands
+{ 'include': 'qapi/trace.json' }
+
 ##
 # LostTickPolicy:
 #
diff --git a/qapi/trace.json b/qapi/trace.json
new file mode 100644
index 0000000..6e6313d
--- /dev/null
+++ b/qapi/trace.json
@@ -0,0 +1,44 @@
+# -*- mode: python -*-
+
+##
+# @TraceEventState:
+#
+# State of a tracing event.
+#
+# @name: Event name.
+# @sstatic: Static tracing state.
+# @sdynamic: Dynamic tracing state.
+#
+# Since 2.2
+##
+{ 'type': 'TraceEventState',
+  'data': {'name': 'str', 'sstatic': 'bool', 'sdynamic': 'bool'} }
+
+##
+# @trace-event-get-state:
+#
+# Query the state of events.
+#
+# @name: Event name pattern.
+#
+# Returns: @TraceEventState of the matched events
+#
+# Since 2.2
+##
+{ 'command': 'trace-event-get-state',
+  'data': {'name': 'str'},
+  'returns': ['TraceEventState'] }
+
+##
+# @trace-event-set-state:
+#
+# Set the dynamic state of events.
+#
+# @name: Event name pattern.
+# @state: Dynamic tracing state.
+# @keepgoing: #optional Apply changes even if not all events can be changed.
+#
+# Since 2.2
+##
+{ 'command': 'trace-event-set-state',
+  'data': {'name': 'str', 'state': 'bool', '*keepgoing': 'bool'} }
diff --git a/qmp-commands.hx b/qmp-commands.hx
index 4be4765..443dd16 100644
--- a/qmp-commands.hx
+++ b/qmp-commands.hx
@@ -3753,5 +3753,32 @@ Example:
 
 -> { "execute": "rtc-reset-reinjection" }
 <- { "return": {} }
+EQMP
+
+    {
+        .name       = "trace-event-get-state",
+        .args_type  = "name:s",
+        .mhandler.cmd_new = qmp_marshal_input_trace_event_get_state,
+    },
+
+SQMP
+trace-event-get-state
+---------------------
+
+Query the state of events.
+
+EQMP
+
+    {
+        .name       = "trace-event-set-state",
+        .args_type  = "name:s,state:b,keepgoing:b?",
+        .mhandler.cmd_new = qmp_marshal_input_trace_event_set_state,
+    },
+
+SQMP
+trace-event-set-state
+---------------------
+
+Set the state of events.
 
 EQMP
diff --git a/trace/Makefile.objs b/trace/Makefile.objs
index 387f191..01b3718 100644
--- a/trace/Makefile.objs
+++ b/trace/Makefile.objs
@@ -145,3 +145,4 @@ util-obj-$(CONFIG_TRACE_FTRACE) += ftrace.o
 util-obj-$(CONFIG_TRACE_UST) += generated-ust.o
 util-obj-y += control.o
 util-obj-y += generated-tracers.o
+util-obj-y += qmp.o
diff --git a/trace/control.c b/trace/control.c
index 9631a40..0d30801 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -85,19 +85,6 @@ TraceEvent *trace_event_pattern(const char *pat, TraceEvent 
*ev)
     return NULL;
 }
 
-void trace_print_events(FILE *stream, fprintf_function stream_printf)
-{
-    TraceEventID i;
-
-    for (i = 0; i < trace_event_count(); i++) {
-        TraceEvent *ev = trace_event_id(i);
-        stream_printf(stream, "%s [Event ID %u] : state %u\n",
-                      trace_event_get_name(ev), i,
-                      trace_event_get_state_static(ev) &&
-                      trace_event_get_state_dynamic(ev));
-    }
-}
-
 static void trace_init_events(const char *fname)
 {
     Location loc;
diff --git a/trace/control.h b/trace/control.h
index e1ec033..da9bb6b 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -149,13 +149,6 @@ static void trace_event_set_state_dynamic(TraceEvent *ev, 
bool state);
 
 
 /**
- * trace_print_events:
- *
- * Print the state of all events.
- */
-void trace_print_events(FILE *stream, fprintf_function stream_printf);
-
-/**
  * trace_init_backends:
  * @events: Name of file with events to be enabled at startup; may be NULL.
  *          Corresponds to commandline option "-trace events=...".
diff --git a/trace/qmp.c b/trace/qmp.c
new file mode 100644
index 0000000..d22d8fa
--- /dev/null
+++ b/trace/qmp.c
@@ -0,0 +1,77 @@
+/*
+ * QMP commands for tracing events.
+ *
+ * Copyright (C) 2014 Lluís Vilanova <address@hidden>
+ *
+ * This work is licensed under the terms of the GNU GPL, version 2 or later.
+ * See the COPYING file in the top-level directory.
+ */
+
+#include "qemu/typedefs.h"
+#include "qmp-commands.h"
+#include "trace/control.h"
+
+
+TraceEventStateList *qmp_trace_event_get_state(const char *name, Error **errp)
+{
+    TraceEventStateList dummy = {};
+    TraceEventStateList *prev = &dummy;
+
+    bool found = false;
+    TraceEvent *ev = NULL;
+    while ((ev = trace_event_pattern(name, ev)) != NULL) {
+        found = true;
+        TraceEventStateList *elem = g_malloc0(sizeof(*elem));
+        elem->value = g_malloc0(sizeof(*elem->value));
+        elem->value->name = g_strdup(trace_event_get_name(ev));
+        elem->value->sstatic = trace_event_get_state_static(ev);
+        elem->value->sdynamic = trace_event_get_state_dynamic(ev);
+        prev->next = elem;
+        prev = elem;
+    }
+    if (!found && !trace_event_is_pattern(name)) {
+        error_setg(errp, "unknown event \"%s\"\n", name);
+    }
+
+    return dummy.next;
+}
+
+void qmp_trace_event_set_state(const char *name, bool state, bool 
has_keepgoing,
+                               bool keepgoing, Error **errp)
+{
+    bool error = false;
+    bool found = false;
+    TraceEvent *ev = NULL;
+
+    /* Check all selected events are dynamic */
+    while ((ev = trace_event_pattern(name, ev)) != NULL) {
+        found = true;
+        if (!trace_event_get_state_static(ev)) {
+            error_setg(errp, "cannot set dynamic tracing state for \"%s\"\n",
+                       trace_event_get_name(ev));
+            if (!(has_keepgoing && keepgoing)) {
+                error = true;
+            }
+            break;
+        }
+    }
+    if (error) {
+        return;
+    }
+    if (!found && !trace_event_is_pattern(name)) {
+        error_setg(errp, "unknown event \"%s\"\n", name);
+        return;
+    }
+
+    if (error) {
+        return;
+    }
+
+    /* Apply changes */
+    ev = NULL;
+    while ((ev = trace_event_pattern(name, ev)) != NULL) {
+        if (trace_event_get_state_static(ev)) {
+            trace_event_set_state_dynamic(ev, state);
+        }
+    }
+}