[PATCH 3/3] libtracefs: Implement tracefs_kprobe_clear_probe()

[Steven Rostedt <rostedt@goodmis.org>]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

Add the function tracefs_kprobe_clear_probe() that will remove a single
kprobe. If the @force parameter is set, it will disable that probe in all
instances (including the top level instance) before removing it.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
---
 include/tracefs.h     |  1 +
 src/tracefs-kprobes.c | 36 ++++++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+)

diff --git a/include/tracefs.h b/include/tracefs.h
index 54c461e85a2b..447821e65ce2 100644
--- a/include/tracefs.h
+++ b/include/tracefs.h
@@ -213,4 +213,5 @@ void tracefs_trace_pipe_stop(struct tracefs_instance *instance);
 int tracefs_kprobe_raw(const char *system, const char *event,
 		       const char *addr, const char *format);
 int tracefs_kprobe_clear(bool force);
+int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force);
 #endif /* _TRACE_FS_H */
diff --git a/src/tracefs-kprobes.c b/src/tracefs-kprobes.c
index 48a4f090f041..27d4c2181404 100644
--- a/src/tracefs-kprobes.c
+++ b/src/tracefs-kprobes.c
@@ -204,3 +204,39 @@ int tracefs_kprobe_clear(bool force)
 	free_instance_list(list);
 	return ret;
 }
+
+int tracefs_kprobe_clear_probe(const char *system, const char *event, bool force)
+{
+	struct instance_list *list = NULL;
+	struct instance_list **plist = &list;
+	char *content;
+	int ret;
+
+	if (!system)
+		system = "kprobes";
+
+	ret = asprintf(&content, "-:%s/%s", system, event);
+	if (ret < 0)
+		return -1;
+
+	/*
+	 * Since we know we are disabling a specific event, try
+	 * to disable it first before clearing it.
+	 */
+	if (force) {
+		ret = tracefs_instances_walk(build_instances, &plist);
+		if (ret < 0)
+			goto out;
+
+		ret = disable_events(system, event, list);
+		if (ret < 0)
+			goto out;
+	}
+
+	ret = tracefs_instance_file_append(NULL, KPROBE_EVENTS, content);
+ out:
+	free(content);
+	free_instance_list(list);
+
+	return ret < 0 ? -1 : 0;
+}
-- 
2.30.2