Commit 9aed4e15 authored by Beau Belgrave's avatar Beau Belgrave Committed by Steven Rostedt (Google)
Browse files

user_events: Handle matching arguments from dyn_events 

Ensures that when dynamic events requests a match with arguments that
they match what is in the user_event.

Link: https://lkml.kernel.org/r/20220118204326.2169-4-beaub@linux.microsoft.com



Acked-by: default avatarMasami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: default avatarBeau Belgrave <beaub@linux.microsoft.com>
Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent aa3b2b4c

kernel/trace/trace_events_user.c

+76 −1
Original line number Diff line number Diff line
@@ -39,6 +39,7 @@ 
#define MAX_EVENT_DESC 512

#define EVENT_NAME(user_event) ((user_event)->tracepoint.name)

#define MAX_FIELD_ARRAY_SIZE 1024

#define MAX_FIELD_ARG_NAME 256



static char *register_page_data;
@@ -700,13 +701,87 @@ static int user_event_free(struct dyn_event *ev) 
	return destroy_user_event(user);

}



static bool user_field_match(struct ftrace_event_field *field, int argc,

			     const char **argv, int *iout)

{

	char *field_name, *arg_name;

	int len, pos, i = *iout;

	bool colon = false, match = false;



	if (i >= argc)

		return false;



	len = MAX_FIELD_ARG_NAME;

	field_name = kmalloc(len, GFP_KERNEL);

	arg_name = kmalloc(len, GFP_KERNEL);



	if (!arg_name || !field_name)

		goto out;



	pos = 0;



	for (; i < argc; ++i) {

		if (i != *iout)

			pos += snprintf(arg_name + pos, len - pos, " ");



		pos += snprintf(arg_name + pos, len - pos, argv[i]);



		if (strchr(argv[i], ';')) {

			++i;

			colon = true;

			break;

		}

	}



	pos = 0;



	pos += snprintf(field_name + pos, len - pos, field->type);

	pos += snprintf(field_name + pos, len - pos, " ");

	pos += snprintf(field_name + pos, len - pos, field->name);



	if (colon)

		pos += snprintf(field_name + pos, len - pos, ";");



	*iout = i;



	match = strcmp(arg_name, field_name) == 0;

out:

	kfree(arg_name);

	kfree(field_name);



	return match;

}



static bool user_fields_match(struct user_event *user, int argc,

			      const char **argv)

{

	struct ftrace_event_field *field, *next;

	struct list_head *head = &user->fields;

	int i = 0;



	list_for_each_entry_safe_reverse(field, next, head, link)

		if (!user_field_match(field, argc, argv, &i))

			return false;



	if (i != argc)

		return false;



	return true;

}



static bool user_event_match(const char *system, const char *event,

			     int argc, const char **argv, struct dyn_event *ev)

{

	struct user_event *user = container_of(ev, struct user_event, devent);

	bool match;



	return strcmp(EVENT_NAME(user), event) == 0 &&

	match = strcmp(EVENT_NAME(user), event) == 0 &&

		(!system || strcmp(system, USER_EVENTS_SYSTEM) == 0);



	if (match && argc > 0)

		match = user_fields_match(user, argc, argv);



	return match;

}



static struct dyn_event_operations user_event_dops = {