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From:   Daniel Bristot de Oliveira <bristot@kernel.org>
To:     Steven Rostedt <rostedt@goodmis.org>
Cc:     Daniel Bristot de Oliveira <bristot@kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        linux-trace-devel@vger.kernel.org, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: [PATCH 5/7] rtla/trace: Add trace events helpers
Date:   Fri, 18 Feb 2022 12:09:17 +0100
Message-Id: <fc83e3162dd01df0b1635099fbf1f5b08b069834.1645182327.git.bristot@kernel.org>
In-Reply-To: <cover.1645182327.git.bristot@kernel.org>
References: <cover.1645182327.git.bristot@kernel.org>
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Add a set of helper functions to allow the rtla tools to enable
additional tracepoints in the trace instance.

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
---
 tools/tracing/rtla/src/trace.c | 105 +++++++++++++++++++++++++++++++++
 tools/tracing/rtla/src/trace.h |  15 +++++
 2 files changed, 120 insertions(+)

diff --git a/tools/tracing/rtla/src/trace.c b/tools/tracing/rtla/src/trace.c
index 83de259abcc1..1a3e346c6b17 100644
--- a/tools/tracing/rtla/src/trace.c
+++ b/tools/tracing/rtla/src/trace.c
@@ -190,3 +190,108 @@ int trace_instance_start(struct trace_instance *trace)
 {
 	return tracefs_trace_on(trace->inst);
 }
+
+/*
+ * free_trace_events - free a list of trace events
+ */
+static void free_trace_events(struct trace_events *events)
+{
+	struct trace_events *tevent = events;
+	struct trace_events *free_event;
+
+	while (tevent) {
+		free_event = tevent;
+
+		tevent = tevent->next;
+
+		free(free_event->system);
+		free(free_event);
+	}
+}
+
+/*
+ * alloc_trace_event - alloc and parse a single trace event
+ */
+struct trace_events *alloc_trace_event(const char *event_string)
+{
+	struct trace_events *tevent;
+
+	tevent = calloc(1, sizeof(*tevent));
+	if (!tevent)
+		return NULL;
+
+	tevent->system = strdup(event_string);
+	if (!tevent->system) {
+		free(tevent);
+		return NULL;
+	}
+
+	tevent->event = strstr(tevent->system, ":");
+	if (tevent->event) {
+		*tevent->event = '\0';
+		tevent->event = &tevent->event[1];
+	}
+
+	return tevent;
+}
+
+/*
+ * disable_trace_events - disable all trace events
+ */
+void disable_trace_events(struct trace_instance *instance,
+			  struct trace_events *events)
+{
+	struct trace_events *tevent = events;
+
+	if (!events)
+		return;
+
+	while (tevent) {
+		if (tevent->enabled)
+			tracefs_event_disable(instance->inst, tevent->system, tevent->event);
+
+		tevent->enabled = 0;
+		tevent = tevent->next;
+	}
+}
+
+/*
+ * enable_trace_events - enable all events
+ */
+int enable_trace_events(struct trace_instance *instance,
+			struct trace_events *events)
+{
+	struct trace_events *tevent = events;
+	int retval;
+
+	while (tevent) {
+		retval = tracefs_event_enable(instance->inst, tevent->system, tevent->event);
+		if (retval < 0) {
+			if (tevent->event)
+				err_msg("Error enabling event %s:%s\n",
+					tevent->system, tevent->event);
+			else
+				err_msg("Error enabling events %s:*\n",
+					tevent->system);
+			return 1;
+		}
+
+		tevent->enabled = 1;
+		tevent = tevent->next;
+	}
+
+	return 0;
+}
+
+/*
+ * destroy_trace_events - disable and free all trace events
+ */
+void destroy_trace_events(struct trace_instance *instance,
+			  struct trace_events *events)
+{
+	if (!events)
+		return;
+
+	disable_trace_events(instance, events);
+	free_trace_events(events);
+}
diff --git a/tools/tracing/rtla/src/trace.h b/tools/tracing/rtla/src/trace.h
index 0ea1df0ad9a7..762a04667c51 100644
--- a/tools/tracing/rtla/src/trace.h
+++ b/tools/tracing/rtla/src/trace.h
@@ -2,6 +2,13 @@
 #include <tracefs.h>
 #include <stddef.h>
 
+struct trace_events {
+	struct trace_events *next;
+	char *system;
+	char *event;
+	int enabled;
+};
+
 struct trace_instance {
 	struct tracefs_instance		*inst;
 	struct tep_handle		*tep;
@@ -25,3 +32,11 @@ void destroy_instance(struct tracefs_instance *inst);
 int save_trace_to_file(struct tracefs_instance *inst, const char *filename);
 int collect_registered_events(struct tep_event *tep, struct tep_record *record,
 			      int cpu, void *context);
+
+struct trace_events *alloc_trace_event(const char *event_string);
+void disable_trace_events(struct trace_instance *instance,
+			  struct trace_events *events);
+void destroy_trace_events(struct trace_instance *instance,
+			  struct trace_events *events);
+int enable_trace_events(struct trace_instance *instance,
+			  struct trace_events *events);
-- 
2.34.1