perf config: Add config set interface

Add interface to load config set from custom file by using
perf_config_set__load_file function.

It will be used in perf daemon command to process custom config file.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Budankov <abudankov@huawei.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lore.kernel.org/lkml/20210102220441.794923-3-jolsa@kernel.orgSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/util/config.c

@@ -738,6 +738,18 @@ struct perf_config_set *perf_config_set__new(void)
 	return set;
 }
 
+struct perf_config_set *perf_config_set__load_file(const char *file)
+{
+	struct perf_config_set *set = zalloc(sizeof(*set));
+
+	if (set) {
+		INIT_LIST_HEAD(&set->sections);
+		perf_config_from_file(collect_config, file, set);
+	}
+
+	return set;
+}
+
 static int perf_config__init(void)
 {
 	if (config_set == NULL)
@@ -746,17 +758,15 @@ static int perf_config__init(void)
 	return config_set == NULL;
 }
 
-int perf_config(config_fn_t fn, void *data)
+int perf_config_set(struct perf_config_set *set,
+		    config_fn_t fn, void *data)
 {
 	int ret = 0;
 	char key[BUFSIZ];
 	struct perf_config_section *section;
 	struct perf_config_item *item;
 
-	if (config_set == NULL && perf_config__init())
-		return -1;
-
-	perf_config_set__for_each_entry(config_set, section, item) {
+	perf_config_set__for_each_entry(set, section, item) {
 		char *value = item->value;
 
 		if (value) {
@@ -778,6 +788,14 @@ int perf_config(config_fn_t fn, void *data)
 	return ret;
 }
 
+int perf_config(config_fn_t fn, void *data)
+{
+	if (config_set == NULL && perf_config__init())
+		return -1;
+
+	return perf_config_set(config_set, fn, data);
+}
+
 void perf_config__exit(void)
 {
 	perf_config_set__delete(config_set);

tools/perf/util/config.h

@@ -29,6 +29,8 @@ typedef int (*config_fn_t)(const char *, const char *, void *);
 
 int perf_default_config(const char *, const char *, void *);
 int perf_config(config_fn_t fn, void *);
+int perf_config_set(struct perf_config_set *set,
+		    config_fn_t fn, void *data);
 int perf_config_int(int *dest, const char *, const char *);
 int perf_config_u8(u8 *dest, const char *name, const char *value);
 int perf_config_u64(u64 *dest, const char *, const char *);
@@ -37,6 +39,7 @@ int config_error_nonbool(const char *);
 const char *perf_etc_perfconfig(void);
 
 struct perf_config_set *perf_config_set__new(void);
+struct perf_config_set *perf_config_set__load_file(const char *file);
 void perf_config_set__delete(struct perf_config_set *set);
 int perf_config_set__collect(struct perf_config_set *set, const char *file_name,
 			     const char *var, const char *value);