[PATCH v6 5/9] Optimize default filtering

[Nikolay Marchuk]

* filter_action.c (default_flags, update_default_flags): Add default flags.
(add_action): Clear default flags.
(filter_syscall): Add default_flags to qual_flg.
(filtering_parse_finish): Init trace action for pathtracing. Don't sort empty
actions' array.
* strace.c (init): Remove default filters.
---
 filter_action.c | 26 ++++++++++++++++++++++++++
 strace.c        |  3 ---
 2 files changed, 26 insertions(+), 3 deletions(-)

diff --git a/filter_action.c b/filter_action.c
index f8bca97..74a2d29 100644
--- a/filter_action.c
+++ b/filter_action.c
@@ -90,6 +90,7 @@ struct filter_action {
 	void *_priv_data;
 };
 
+static int default_flags = DEFAULT_QUAL_FLAGS;
 static struct filter_action *filter_actions;
 static unsigned int nfilter_actions;
 
@@ -117,7 +118,14 @@ filtering_parsing_finish(void)
 	unsigned int maxfilters = 0;
 	unsigned int i;
 
+	/* Init trace action if pathtracing is enabled */
+	if (tracing_paths && (default_flags & QUAL_TRACE)) {
+		parse_qualify_filter("trace=all");
+	}
+
 	/* Sort actions by priority */
+	if (nfilter_actions == 0)
+		return;
 	qsort(filter_actions, nfilter_actions, sizeof(struct filter_action),
 	      &compare_action_priority);
 
@@ -128,6 +136,22 @@ filtering_parsing_finish(void)
 	}
 	variables_buf = xcalloc(maxfilters, sizeof(bool));
 }
+static void
+update_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)
@@ -146,6 +170,7 @@ add_action(const struct filter_action_type *type)
 {
 	struct filter_action *action;
 
+	update_default_flags(type->name);
 	filter_actions = xreallocarray(filter_actions, ++nfilter_actions,
 				       sizeof(struct filter_action));
 	action = &filter_actions[nfilter_actions - 1];
@@ -203,6 +228,7 @@ filter_syscall(struct tcb *tcp)
 {
 	unsigned int i;
 
+	tcp->qual_flg |= default_flags;
 	for (i = 0; i < nfilter_actions; ++i)
 		run_filter_action(tcp, &filter_actions[i]);
 }
diff --git a/strace.c b/strace.c
index 0e82cc5..137559c 100644
--- a/strace.c
+++ b/strace.c
@@ -1645,9 +1645,6 @@ 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