[v2] trace-cmd record: Write set_ftrace_filter commands separately

Commit Message

Steven Rostedt May 6, 2021, 3:10 p.m. UTC

From: "Steven Rostedt (VMware)" <[e-mail]>

Using tracefs_function_filter() to enable function filters allowed for
more flexibility on the command line for using regex to enable functions,
but it also broke setting commands like "stacktrace" and "traceoff".

If the filter contains ":" then write it directly into the file instead of
going through the tracefs_function_filter interface.

Fixes: f73378a7b ("trace-cmd record: Use tracefs_filter_function() for function filtering")
Signed-off-by: Steven Rostedt (VMware) <[e-mail]>
---

Changes since v1:

 - Open coded the tracefs_instance_file_append(), as that is not part
   of libtracefs 1.1, and I did not want to up the required library
   to 1.2.

 tracecmd/trace-record.c | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

Patch

diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
index fd03a605..3ce35d76 100644
--- a/tracecmd/trace-record.c
+++ b/tracecmd/trace-record.c
@@ -4356,10 +4356,28 @@  enum filter_type {
 	FUNC_NOTRACE,
 };
 
+static int filter_command(struct tracefs_instance *instance, const char *cmd)
+{
+	char *path;
+	int ret;
+	int fd;
+
+	path = tracefs_instance_get_file(instance, "set_ftrace_filter");
+	if (!path)
+		return -1;
+	fd = open(path, O_WRONLY);
+	tracefs_put_tracing_file(path);
+	if (fd < 0)
+		return -1;
+	ret = write(fd, cmd, strlen(cmd));
+	close(fd);
+	return ret;
+}
+
 static int write_func_filter(enum filter_type type, struct buffer_instance *instance,
 			     struct func_list **list)
 {
-	struct func_list *item;
+	struct func_list *item, *cmds = NULL;
 	const char *file;
 	int ret = -1;
 	int (*filter_function)(struct tracefs_instance *instance, const char *filter,
@@ -4387,6 +4405,12 @@  static int write_func_filter(enum filter_type type, struct buffer_instance *inst
 	while (*list) {
 		item = *list;
 		*list = item->next;
+		/* Do commands separately at the end */
+		if (type == FUNC_FILTER && strstr(item->func, ":")) {
+			item->next = cmds;
+			cmds = item;
+			continue;
+		}
 		ret = filter_function(instance->tracefs, item->func, item->mod,
 				      TRACEFS_FL_CONTINUE);
 		if (ret < 0)
@@ -4394,6 +4418,16 @@  static int write_func_filter(enum filter_type type, struct buffer_instance *inst
 		free(item);
 	}
 	ret = filter_function(instance->tracefs, NULL, NULL, 0);
+
+	/* Now add any commands */
+	while (cmds) {
+		item = cmds;
+		cmds = item->next;
+		ret = filter_command(instance->tracefs, item->func);
+		if (ret < 0)
+			goto failed;
+		free(item);
+	}
 	return ret;
  failed:
 	die("Failed to write %s to %s.\n"