1 files changed, 125 insertions, 0 deletions
diff --git a/tracecmd/trace-clear.c b/tracecmd/trace-clear.c
new file mode 100644
index 00000000..999e80fe
--- /dev/null
+++ b/tracecmd/trace-clear.c
@@ -0,0 +1,125 @@
+// SPDX-License-Identifier: LGPL-2.1
+/*
+ * Copyright (C) 2008, 2009, 2010 Red Hat Inc, Steven Rostedt <srostedt@redhat.com>
+ *
+ * Updates:
+ * Copyright (C) 2020, VMware, Tzvetomir Stoyanov <tz.stoyanov@gmail.com>
+ *
+ */
+#include <stdlib.h>
+#include <unistd.h>
+#include <getopt.h>
+
+#include "tracefs.h"
+#include "trace-local.h"
+
+struct instances_list {
+	struct instances_list *next;
+	struct tracefs_instance *instance;
+};
+
+static int add_new_instance(struct instances_list **list, char *name)
+{
+	struct instances_list *new;
+
+	if (!tracefs_instance_exists(name))
+		return -1;
+	new = calloc(1, sizeof(*new));
+	if (!new)
+		return -1;
+	new->instance = tracefs_instance_create(name);
+	if (!new->instance) {
+		free(new);
+		return -1;
+	}
+
+	new->next = *list;
+	*list = new;
+	return 0;
+}
+
+static int add_instance_walk(const char *name, void *data)
+{
+	return add_new_instance((struct instances_list **)data, (char *)name);
+}
+
+static void clear_list(struct instances_list *list)
+{
+	struct instances_list *del;
+
+	while (list) {
+		del = list;
+		list = list->next;
+		tracefs_instance_free(del->instance);
+		free(del);
+	}
+}
+
+static void clear_instance_trace(struct tracefs_instance *instance)
+{
+	FILE *fp;
+	char *path;
+
+	/* reset the trace */
+	path = tracefs_instance_get_file(instance, "trace");
+	fp = fopen(path, "w");
+	if (!fp)
+		die("writing to '%s'", path);
+	tracefs_put_tracing_file(path);
+	fwrite("0", 1, 1, fp);
+	fclose(fp);
+}
+
+static void clear_trace(struct instances_list *instances)
+{
+	if (instances) {
+		while (instances) {
+			clear_instance_trace(instances->instance);
+			instances = instances->next;
+		}
+	} else
+		clear_instance_trace(NULL);
+}
+
+void trace_clear(int argc, char **argv)
+{
+	struct instances_list *instances = NULL;
+	bool all = false;
+	int c;
+
+	for (;;) {
+		int option_index = 0;
+		static struct option long_options[] = {
+			{"all", no_argument, NULL, 'a'},
+			{"help", no_argument, NULL, '?'},
+			{NULL, 0, NULL, 0}
+		};
+
+		c = getopt_long (argc-1, argv+1, "+haB:",
+				 long_options, &option_index);
+		if (c == -1)
+			break;
+		switch (c) {
+		case 'B':
+			if (add_new_instance(&instances, optarg))
+				die("Failed to allocate instance %s", optarg);
+			break;
+		case 'a':
+			all = true;
+			if (tracefs_instances_walk(add_instance_walk, &instances))
+				die("Failed to add all instances");
+			break;
+		case 'h':
+		case '?':
+		default:
+			usage(argv);
+			break;
+		}
+	}
+
+	clear_trace(instances);
+	if (all)
+		clear_trace(NULL);
+	clear_list(instances);
+	exit(0);
+}