[PATCH 1/3] tracing/filters: allow user-input to be integer-like string

[Li Zefan <lizf@cn.fujitsu.com>]

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().

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
---
 kernel/trace/trace_events_filter.c |   26 +++++++++++++-------------
 1 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 9f8ecca..a63f965 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -229,6 +229,7 @@ static int is_string_field(const char *type)
 int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
 {
 	struct ftrace_event_field *field;
+	unsigned long long val;
 
 	field = find_event_field(call, pred->field_name);
 	if (!field)
@@ -237,14 +238,14 @@ int filter_add_pred(struct ftrace_event_call *call, struct filter_pred *pred)
 	pred->offset = field->offset;
 
 	if (is_string_field(field->type)) {
-		if (!pred->str_val)
-			return -EINVAL;
 		pred->fn = filter_pred_string;
 		pred->str_len = field->size;
 		return __filter_add_pred(call, pred);
 	} else {
-		if (pred->str_val)
+		if (strict_strtoull(pred->str_val, 0, &val))
 			return -EINVAL;
+		pred->val = val;
+		kfree(pred->str_val);
 	}
 
 	switch (field->size) {
@@ -351,12 +352,16 @@ oom:
 	return -ENOMEM;
 }
 
+/*
+ * 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")) {
@@ -419,15 +424,10 @@ int filter_parse(char **pbuf, struct filter_pred *pred)
 	if (!pred->field_name)
 		return -ENOMEM;
 
-	pred->val = simple_strtoull(val_str, &tmp, 0);
-	if (tmp == val_str) {
-		pred->str_val = kstrdup(val_str, GFP_KERNEL);
-		if (!pred->str_val)
-			return -ENOMEM;
-	} else if (*tmp != '\0')
-		return -EINVAL;
+	pred->str_val = kstrdup(val_str, GFP_KERNEL);
+	if (!pred->str_val)
+		return -ENOMEM;
 
 	return 0;
 }
 
-
-- 
1.5.4.rc3