[Qemu-devel] [PATCH v6 08/14] trace-state: separate trace event control and query routines from the simple backend

[Lluís]

Move the 'st_print_trace_events' and 'st_change_trace_event_state' into
backend-agnostic 'trace_print_events' and 'trace_event_set_state' (respectively)
in the "trace/control.c" file.

Uses "QEMU_WEAK" to provide a default implementation that signals it as not
implemented.

Backends can provide their own implementation if supported.

Signed-off-by: Lluís Vilanova <address@hidden>
---
 Makefile.objs   |    1 +
 hmp-commands.hx |    2 +-
 monitor.c       |   11 ++++++-----
 trace/control.c |   11 +++++++++++
 trace/control.h |   17 ++++++++++++-----
 trace/simple.c  |   16 ++++++++--------
 trace/simple.h  |    2 --
 7 files changed, 39 insertions(+), 21 deletions(-)

diff --git a/Makefile.objs b/Makefile.objs
index 3530bcf..8950086 100644
--- a/Makefile.objs
+++ b/Makefile.objs
@@ -378,6 +378,7 @@ trace-obj-$(CONFIG_TRACE_SYSTEMTAP) += trace-dtrace.o
 ifneq ($(TRACE_BACKEND),dtrace)
 trace-obj-y = trace.o
 endif
+trace-obj-y += trace/control.o
 
 trace-nested-$(CONFIG_TRACE_SIMPLE) += simple.o
 trace-obj-$(CONFIG_TRACE_SIMPLE) += qemu-timer-common.o
diff --git a/hmp-commands.hx b/hmp-commands.hx
index ad4174f..d77e75f 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -186,7 +186,7 @@ ETEXI
         .args_type  = "name:s,option:b",
         .params     = "name on|off",
         .help       = "changes status of a specific trace event",
-        .mhandler.cmd = do_change_trace_event_state,
+        .mhandler.cmd = do_trace_event_set_state,
     },
 
 STEXI
diff --git a/monitor.c b/monitor.c
index 9c6e99c..74cb6a2 100644
--- a/monitor.c
+++ b/monitor.c
@@ -60,6 +60,7 @@
 #ifdef CONFIG_TRACE_SIMPLE
 #include "trace.h"
 #endif
+#include "trace/control.h"
 #include "ui/qemu-spice.h"
 
 //#define DEBUG
@@ -593,11 +594,11 @@ static void do_help_cmd(Monitor *mon, const QDict *qdict)
 }
 
 #ifdef CONFIG_TRACE_SIMPLE
-static void do_change_trace_event_state(Monitor *mon, const QDict *qdict)
+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");
-    int ret = st_change_trace_event_state(tp_name, new_state);
+    int ret = trace_event_set_state(tp_name, new_state);
 
     if (!ret) {
         monitor_printf(mon, "unknown event name \"%s\"\n", tp_name);
@@ -1002,9 +1003,9 @@ static void do_info_trace(Monitor *mon)
     st_print_trace((FILE *)mon, &monitor_fprintf);
 }
 
-static void do_info_trace_events(Monitor *mon)
+static void do_trace_print_events(Monitor *mon)
 {
-    st_print_trace_events((FILE *)mon, &monitor_fprintf);
+    trace_print_events((FILE *)mon, &monitor_fprintf);
 }
 #endif
 
@@ -3148,7 +3149,7 @@ static const mon_cmd_t info_cmds[] = {
         .args_type  = "",
         .params     = "",
         .help       = "show available trace-events & their state",
-        .mhandler.info = do_info_trace_events,
+        .mhandler.info = do_trace_print_events,
     },
 #endif
     {
diff --git a/trace/control.c b/trace/control.c
index cb14f4b..b27ba30 100644
--- a/trace/control.c
+++ b/trace/control.c
@@ -11,6 +11,17 @@
 
 #include "trace/control.h"
 
+void trace_print_events (FILE *stream, fprintf_function stream_printf)
+{
+    fprintf(stderr, "qemu: warning: cannot print the trace events with the 
current backend\n");
+    stream_printf(stream, "error: operation not supported with the current 
backend\n");
+}
+
+bool trace_event_set_state (const char *name, bool state)
+{
+    fprintf(stderr, "qemu: warning: cannot set the state of a trace event with 
the current backend\n");
+    return false;
+}
 
 bool trace_config_init (void)
 {
diff --git a/trace/control.h b/trace/control.h
index 8b52d5e..d1e277b 100644
--- a/trace/control.h
+++ b/trace/control.h
@@ -7,15 +7,22 @@
  * the COPYING file in the top-level directory.
  */
 
-#ifndef TRACE_CONFIG_H
-#define TRACE_CONFIG_H
-
-#include <stdbool.h>
+#ifndef TRACE_CONTROL_H
+#define TRACE_CONTROL_H
 
+#include "qemu-common.h"
 #include "compiler.h"
 
 /* Backends can re-implement routines marked as QEMU_WEAK */
 
+/** Print the state of all events. */
+void trace_print_events (FILE *stream, fprintf_function stream_printf) 
QEMU_WEAK;
+/** Set the state of an event.
+ *
+ * @return Whether the state changed.
+ */
+bool trace_event_set_state (const char *name, bool state) QEMU_WEAK;
+
 /** Whether any cmdline trace option is avilable. */
 bool trace_config_init (void) QEMU_WEAK;
 /** Configure output trace file.
@@ -24,4 +31,4 @@ bool trace_config_init (void) QEMU_WEAK;
  */
 bool trace_config_init_file (const char *file) QEMU_WEAK;
 
-#endif  /* TRACE_CONFIG_H */
+#endif  /* TRACE_CONTROL_H */
diff --git a/trace/simple.c b/trace/simple.c
index f3891c1..aa6403e 100644
--- a/trace/simple.c
+++ b/trace/simple.c
@@ -303,7 +303,12 @@ void st_print_trace(FILE *stream, int 
(*stream_printf)(FILE *stream, const char
     }
 }
 
-void st_print_trace_events(FILE *stream, int (*stream_printf)(FILE *stream, 
const char *fmt, ...))
+void st_flush_trace_buffer(void)
+{
+    flush_trace_file(true);
+}
+
+void trace_print_events (FILE *stream, fprintf_function stream_printf)
 {
     unsigned int i;
 
@@ -313,24 +318,19 @@ void st_print_trace_events(FILE *stream, int 
(*stream_printf)(FILE *stream, cons
     }
 }
 
-bool st_change_trace_event_state(const char *name, bool enabled)
+bool trace_event_set_state (const char *name, bool state)
 {
     unsigned int i;
 
     for (i = 0; i < NR_TRACE_EVENTS; i++) {
         if (!strcmp(trace_list[i].tp_name, name)) {
-            trace_list[i].state = enabled;
+            trace_list[i].state = state;
             return true;
         }
     }
     return false;
 }
 
-void st_flush_trace_buffer(void)
-{
-    flush_trace_file(true);
-}
-
 bool trace_config_init (void)
 {
     pthread_t thread;
diff --git a/trace/simple.h b/trace/simple.h
index 08b9a52..466e75b 100644
--- a/trace/simple.h
+++ b/trace/simple.h
@@ -30,8 +30,6 @@ void trace4(TraceEventID event, uint64_t x1, uint64_t x2, 
uint64_t x3, uint64_t
 void trace5(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, 
uint64_t x4, uint64_t x5);
 void trace6(TraceEventID event, uint64_t x1, uint64_t x2, uint64_t x3, 
uint64_t x4, uint64_t x5, uint64_t x6);
 void st_print_trace(FILE *stream, fprintf_function stream_printf);
-void st_print_trace_events(FILE *stream, fprintf_function stream_printf);
-bool st_change_trace_event_state(const char *tname, bool tstate);
 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);