[Qemu-devel] [PATCH v2] trace: [qmp] Add QAPI/QMP commands to query and control event tracing state

["Lluís Vilanova" <vilanova@ac.upc.edu>]

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

Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
---
 hmp-commands.hx     |   35 -----------------------
 monitor.c           |   61 ----------------------------------------
 qapi-schema.json    |    3 ++
 qmp-commands.hx     |   27 ++++++++++++++++++
 trace/Makefile.objs |    1 +
 trace/commands.json |   44 +++++++++++++++++++++++++++++
 trace/control.c     |   13 ---------
 trace/control.h     |    7 -----
 trace/qmp.c         |   77 +++++++++++++++++++++++++++++++++++++++++++++++++++
 trace/simple.c      |   10 +------
 trace/simple.h      |    3 --
 11 files changed, 154 insertions(+), 127 deletions(-)
 create mode 100644 trace/commands.json
 create mode 100644 trace/qmp.c

diff --git a/hmp-commands.hx b/hmp-commands.hx
index d0943b1..a0d8999 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -269,36 +269,6 @@ Output logs to @var{filename}.
 ETEXI
 
     {
-        .name       = "trace-event",
-        .args_type  = "name:s,option:b",
-        .params     = "name on|off",
-        .help       = "changes status of a specific trace event",
-        .mhandler.cmd = do_trace_event_set_state,
-    },
-
-STEXI
-@item trace-event
-@findex trace-event
-changes status of a trace event
-ETEXI
-
-#if defined(CONFIG_TRACE_SIMPLE)
-    {
-        .name       = "trace-file",
-        .args_type  = "op:s?,arg:F?",
-        .params     = "on|off|flush|set [arg]",
-        .help       = "open, close, or flush trace file, or set a new file name",
-        .mhandler.cmd = do_trace_file,
-    },
-
-STEXI
-@item trace-file on|off|flush
-@findex trace-file
-Open, close, or flush the trace file.  If no argument is given, the status of the trace file is displayed.
-ETEXI
-#endif
-
-    {
         .name       = "log",
         .args_type  = "items:s",
         .params     = "item1[,...]",
@@ -1784,10 +1754,5 @@ show the TPM device
 ETEXI
 
 STEXI
-@item info trace-events
-show available trace events and their state
-ETEXI
-
-STEXI
 @end table
 ETEXI
diff --git a/monitor.c b/monitor.c
index cdbaa60..d856d84 100644
--- a/monitor.c
+++ b/monitor.c
@@ -61,10 +61,6 @@
 #include "qemu/osdep.h"
 #include "cpu.h"
 #include "trace.h"
-#include "trace/control.h"
-#ifdef CONFIG_TRACE_SIMPLE
-#include "trace/simple.h"
-#endif
 #include "exec/memory.h"
 #include "exec/cpu_ldst.h"
 #include "qmp-commands.h"
@@ -882,51 +878,6 @@ static void do_help_cmd(Monitor *mon, const QDict *qdict)
     help_cmd(mon, qdict_get_try_str(qdict, "name"));
 }
 
-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);
-    }
-}
-
-#ifdef CONFIG_TRACE_SIMPLE
-static void do_trace_file(Monitor *mon, const QDict *qdict)
-{
-    const char *op = qdict_get_try_str(qdict, "op");
-    const char *arg = qdict_get_try_str(qdict, "arg");
-
-    if (!op) {
-        st_print_trace_file_status((FILE *)mon, &monitor_fprintf);
-    } else if (!strcmp(op, "on")) {
-        st_set_trace_file_enabled(true);
-    } else if (!strcmp(op, "off")) {
-        st_set_trace_file_enabled(false);
-    } else if (!strcmp(op, "flush")) {
-        st_flush_trace_buffer();
-    } else if (!strcmp(op, "set")) {
-        if (arg) {
-            st_set_trace_file(arg);
-        }
-    } else {
-        monitor_printf(mon, "unexpected argument \"%s\"\n", op);
-        help_cmd(mon, "trace-file");
-    }
-}
-#endif
-
 static void user_monitor_complete(void *opaque, QObject *ret_data)
 {
     MonitorCompletionData *data = (MonitorCompletionData *)opaque; 
@@ -1077,11 +1028,6 @@ static void do_info_cpu_stats(Monitor *mon, const QDict *qdict)
     cpu_dump_statistics(cpu, (FILE *)mon, &monitor_fprintf, 0);
 }
 
-static void do_trace_print_events(Monitor *mon, const QDict *qdict)
-{
-    trace_print_events((FILE *)mon, &monitor_fprintf);
-}
-
 static int client_migrate_info(Monitor *mon, const QDict *qdict,
                                MonitorCompletion cb, void *opaque)
 {
@@ -2898,13 +2844,6 @@ static mon_cmd_t info_cmds[] = {
         .mhandler.cmd = do_info_roms,
     },
     {
-        .name       = "trace-events",
-        .args_type  = "",
-        .params     = "",
-        .help       = "show available trace-events & their state",
-        .mhandler.cmd = do_trace_print_events,
-    },
-    {
         .name       = "tpm",
         .args_type  = "",
         .params     = "",
diff --git a/qapi-schema.json b/qapi-schema.json
index 341f417..0b90f60 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -11,6 +11,9 @@
 # QAPI event definitions
 { 'include': 'qapi/event.json' }
 
+# Tracing commands
+{ 'include': 'trace/commands.json' }
+
 ##
 # LostTickPolicy:
 #
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/commands.json b/trace/commands.json
new file mode 100644
index 0000000..6e6313d
--- /dev/null
+++ b/trace/commands.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/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 <vilanova@ac.upc.edu>
+ *
+ * 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);
+        }
+    }
+}
diff --git a/trace/simple.c b/trace/simple.c
index 11ad030..7a2e44d 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -277,7 +277,7 @@ void trace_record_finish(TraceBufferRecord *rec)
     }
 }
 
-void st_set_trace_file_enabled(bool enable)
+static void st_set_trace_file_enabled(bool enable)
 {
     if (enable == !!trace_fp) {
         return; /* no change */
@@ -322,7 +322,7 @@ void st_set_trace_file_enabled(bool enable)
  * @file        The trace file name or NULL for the default name-<pid> set at
  *              config time
  */
-bool st_set_trace_file(const char *file)
+static bool st_set_trace_file(const char *file)
 {
     st_set_trace_file_enabled(false);
 
@@ -338,12 +338,6 @@ bool st_set_trace_file(const char *file)
     return true;
 }
 
-void st_print_trace_file_status(FILE *stream, int (*stream_printf)(FILE *stream, const char *fmt, ...))
-{
-    stream_printf(stream, "Trace file \"%s\" %s.\n",
-                  trace_file_name, trace_fp ? "on" : "off");
-}
-
 void st_flush_trace_buffer(void)
 {
     flush_trace_file(true);
diff --git a/trace/simple.h b/trace/simple.h
index 6997996..316a479 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -18,9 +18,6 @@
 #include "trace/generated-events.h"
 
 
-void st_print_trace_file_status(FILE *stream, fprintf_function stream_printf);
-void st_set_trace_file_enabled(bool enable);
-bool st_set_trace_file(const char *file);
 bool st_init(const char *file);
 void st_flush_trace_buffer(void);