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Commit f66578a7 authored by Li Zefan's avatar Li Zefan Committed by Ingo Molnar
Browse files

tracing/filters: allow user-input to be integer-like string 



Suppose we would like to trace all tasks named '123', but this
will fail:

 # echo 'parent_comm == 123' > events/sched/sched_process_fork/filter
 bash: echo: write error: Invalid argument

Don't guess the type of the filter pred in filter_parse(), but instead
we check it in __filter_add_pred().

[ Impact: extend allowed filter field string values ]

Signed-off-by: default avatarLi Zefan <lizf@cn.fujitsu.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <49ED8DEB.6000700@cn.fujitsu.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent e8082f3f

kernel/trace/trace_events_filter.c

+12 −14
Original line number Diff line number Diff line
@@ -313,6 +313,7 @@ static int __filter_add_pred(struct ftrace_event_call *call, 
{

	struct ftrace_event_field *field;

	filter_pred_fn_t fn;

	unsigned long long val;



	field = find_event_field(call, pred->field_name);

	if (!field)
@@ -322,14 +323,13 @@ static int __filter_add_pred(struct ftrace_event_call *call, 
	pred->offset = field->offset;



	if (is_string_field(field->type)) {

		if (!pred->str_len)

			return -EINVAL;

		fn = filter_pred_string;

		pred->str_len = field->size;

		return filter_add_pred_fn(call, pred, fn);

	} else {

		if (pred->str_len)

		if (strict_strtoull(pred->str_val, 0, &val))

			return -EINVAL;

		pred->val = val;

	}



	switch (field->size) {
@@ -413,12 +413,16 @@ int filter_add_subsystem_pred(struct event_subsystem *system, 
	return 0;

}



/*

 * The filter format can be

 *   - 0, which means remove all filter preds

 *   - [||/&&] <field> ==/!= <val>

 */

int filter_parse(char **pbuf, struct filter_pred *pred)

{

	char *tmp, *tok, *val_str = NULL;

	char *tok, *val_str = NULL;

	int tok_n = 0;



	/* field ==/!= number, or/and field ==/!= number, number */

	while ((tok = strsep(pbuf, " \n"))) {

		if (tok_n == 0) {

			if (!strcmp(tok, "0")) {
@@ -478,19 +482,13 @@ int filter_parse(char **pbuf, struct filter_pred *pred) 
		return -EINVAL;

	}



	strcpy(pred->str_val, val_str);

	pred->str_len = strlen(val_str);



	pred->field_name = kstrdup(pred->field_name, GFP_KERNEL);

	if (!pred->field_name)

		return -ENOMEM;



	pred->str_len = 0;

	pred->val = simple_strtoull(val_str, &tmp, 0);

	if (tmp == val_str) {

		strncpy(pred->str_val, val_str, MAX_FILTER_STR_VAL);

		pred->str_len = strlen(val_str);

		pred->str_val[pred->str_len] = '\0';

	} else if (*tmp != '\0')

		return -EINVAL;



	return 0;

}