[PATCH v4 4/6] Optimize default filtering

[Nikolay Marchuk]

* filter_action.c (default_flags, clear_default_flags): Add default flags.
(add_action): Clear default flags.
(filter_syscall): Add default_flags to qual_flg.
* strace.c (init): Remove default filters.
---
 filter_action.c | 21 +++++++++++++++++++++
 strace.c        |  3 ---
 2 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/filter_action.c b/filter_action.c
index 3bd3d0c..4c944fc 100644
--- a/filter_action.c
+++ b/filter_action.c
@@ -87,6 +87,7 @@ struct filter_action {
 	void* _priv_data;
 };
 
+static int default_flags = DEFAULT_QUAL_FLAGS;
 static struct filter_action *filter_actions;
 static unsigned int nfilter_actions;
 
@@ -110,6 +111,8 @@ compare_action_priority(const void *a, const void *b)
 void
 filtering_parsing_finish(void)
 {
+	if (nfilter_actions == 0)
+		return;
 	qsort(filter_actions, nfilter_actions, sizeof(struct filter_action),
 	      &compare_action_priority);
 	/* Allocate variables_buf sufficient for any action */
@@ -122,6 +125,22 @@ filtering_parsing_finish(void)
 	variables_buf = xcalloc(maxfilters, sizeof(bool));
 }
 
+static void
+clear_default_flags(const char *name)
+{
+	if ((default_flags & QUAL_TRACE) && !strcmp(name, "trace")) {
+		default_flags &= ~QUAL_TRACE;
+		return;
+	} else if ((default_flags & QUAL_ABBREV) && !strcmp(name, "abbrev")) {
+		default_flags &= ~QUAL_ABBREV;
+		return;
+	} else if ((default_flags & QUAL_VERBOSE) && !strcmp(name, "verbose")) {
+		default_flags &= ~QUAL_VERBOSE;
+		return;
+	}
+
+}
+
 static const struct filter_action_type *
 lookup_filter_action_type(const char *str)
 {
@@ -138,6 +157,7 @@ lookup_filter_action_type(const char *str)
 static struct filter_action *
 add_action(const struct filter_action_type *type)
 {
+	clear_default_flags(type->name);
 	filter_actions = xreallocarray(filter_actions, ++nfilter_actions,
 	                               sizeof(struct filter_action));
 	struct filter_action *action = &filter_actions[nfilter_actions - 1];
@@ -195,6 +215,7 @@ set_qualify_mode(struct filter_action *action)
 void
 filter_syscall(struct tcb *tcp)
 {
+	tcp->qual_flg |= default_flags;
 	unsigned int i;
 	for (i = 0; i < nfilter_actions; i++) {
 		run_filter_action(tcp, &filter_actions[i]);
diff --git a/strace.c b/strace.c
index 6ad367a..b8c027a 100644
--- a/strace.c
+++ b/strace.c
@@ -1637,9 +1637,6 @@ init(int argc, char *argv[])
 	shared_log = stderr;
 	set_sortby(DEFAULT_SORTBY);
 	set_personality(DEFAULT_PERSONALITY);
-	parse_qualify_filter("trace=all");
-	parse_qualify_filter("abbrev=all");
-	parse_qualify_filter("verbose=all");
 #if DEFAULT_QUAL_FLAGS != (QUAL_TRACE | QUAL_ABBREV | QUAL_VERBOSE)
 # error Bug in DEFAULT_QUAL_FLAGS
 #endif
-- 
2.1.4