tracing/filters: Use a different op for glob match

"==" will always do a full match, and "~" will do a glob match.

In the future, we may add "=~" for regex match.

Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <4AD69528.3050309@cn.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 29 insertions, 32 deletions

diff --git a/kernel/trace/trace.h b/kernel/trace/trace.h
index 628614532d16..ffe53ddbe67a 100644
--- a/kernel/trace/trace.h
+++ b/kernel/trace/trace.h
@@ -702,7 +702,7 @@ typedef int (*filter_pred_fn_t) (struct filter_pred *pred, void *event,
 typedef int (*regex_match_func)(char *str, struct regex *r, int len);
 
 enum regex_type {
-        MATCH_FULL,
+        MATCH_FULL = 0,
         MATCH_FRONT_ONLY,
         MATCH_MIDDLE_ONLY,
         MATCH_END_ONLY,
diff --git a/kernel/trace/trace_events_filter.c b/kernel/trace/trace_events_filter.c
index 9c4f9a0dae2b..273845fce393 100644
--- a/kernel/trace/trace_events_filter.c
+++ b/kernel/trace/trace_events_filter.c
@@ -29,6 +29,7 @@ enum filter_op_ids
 {
         OP_OR,
         OP_AND,
+        OP_GLOB,
         OP_NE,
         OP_EQ,
         OP_LT,
@@ -46,16 +47,17 @@ struct filter_op {
 };
 
 static struct filter_op filter_ops[] = {
-        { OP_OR, "||", 1 },
-        { OP_AND, "&&", 2 },
-        { OP_NE, "!=", 4 },
-        { OP_EQ, "==", 4 },
-        { OP_LT, "<", 5 },
-        { OP_LE, "<=", 5 },
-        { OP_GT, ">", 5 },
-        { OP_GE, ">=", 5 },
-        { OP_NONE, "OP_NONE", 0 },
-        { OP_OPEN_PAREN, "(", 0 },
+        { OP_OR,        "||",           1 },
+        { OP_AND,       "&&",           2 },
+        { OP_GLOB,      "~",            4 },
+        { OP_NE,        "!=",           4 },
+        { OP_EQ,        "==",           4 },
+        { OP_LT,        "<",            5 },
+        { OP_LE,        "<=",           5 },
+        { OP_GT,        ">",            5 },
+        { OP_GE,        ">=",           5 },
+        { OP_NONE,      "OP_NONE",      0 },
+        { OP_OPEN_PAREN, "(",           0 },
 };
 
 enum {
@@ -329,22 +331,18 @@ enum regex_type filter_parse_regex(char *buff, int len, char **search, int *not)
         return type;
 }
 
-static int filter_build_regex(struct filter_pred *pred)
+static void filter_build_regex(struct filter_pred *pred)
 {
         struct regex *r = &pred->regex;
-        char *search, *dup;
-        enum regex_type type;
-        int not;
-
-        type = filter_parse_regex(r->pattern, r->len, &search, &not);
-        dup = kstrdup(search, GFP_KERNEL);
-        if (!dup)
-                return -ENOMEM;
-
-        strcpy(r->pattern, dup);
-        kfree(dup);
-
-        r->len = strlen(r->pattern);
+        char *search;
+        enum regex_type type = MATCH_FULL;
+        int not = 0;
+
+        if (pred->op == OP_GLOB) {
+                type = filter_parse_regex(r->pattern, r->len, &search, &not);
+                r->len = strlen(search);
+                memmove(r->pattern, search, r->len+1);
+        }
 
         switch (type) {
         case MATCH_FULL:
@@ -362,8 +360,6 @@ static int filter_build_regex(struct filter_pred *pred)
         }
 
         pred->not ^= not;
-
-        return 0;
 }
 
 /* return 1 if event matches, 0 otherwise (discard) */
@@ -676,7 +672,10 @@ static bool is_string_field(struct ftrace_event_field *field)
 
 static int is_legal_op(struct ftrace_event_field *field, int op)
 {
-        if (is_string_field(field) && (op != OP_EQ && op != OP_NE))
+        if (is_string_field(field) &&
+            (op != OP_EQ && op != OP_NE && op != OP_GLOB))
+                return 0;
+        if (!is_string_field(field) && op == OP_GLOB)
                 return 0;
 
         return 1;
@@ -761,15 +760,13 @@ static int filter_add_pred(struct filter_parse_state *ps,
         }
 
         if (is_string_field(field)) {
-                ret = filter_build_regex(pred);
-                if (ret)
-                        return ret;
+                filter_build_regex(pred);
 
                 if (field->filter_type == FILTER_STATIC_STRING) {
                         fn = filter_pred_string;
                         pred->regex.field_len = field->size;
                 } else if (field->filter_type == FILTER_DYN_STRING)
-                                fn = filter_pred_strloc;
+                        fn = filter_pred_strloc;
                 else {
                         fn = filter_pred_pchar;
                         pred->regex.field_len = strlen(pred->regex.pattern);