[PATCH v16 1/8] perf config: Collect configs to handle config variables

[Taeung Song]

Collecting configs into list because of two reason.

First of all, if there are same variables both user
and system config file, they all will be printed
when 'list' command work. But if config variables are
duplicated, user config variables should only be printed
because it has priority.

Lastly, list into which configs is collected
will be required to keep and handle config variables
and values in the near furture. For example,
getting or setting functionality.

And change show_config() function.
Old show_config() worked depending on perf_config().
New show_config() work using collected configs list.

Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Taeung Song <treeze.taeung@xxxxxxxxx>
---
 tools/perf/builtin-config.c | 150 ++++++++++++++++++++++++++++++++++++++++++--
 tools/perf/util/cache.h     |  13 ++++
 2 files changed, 158 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index c42448e..c43234e 100644
--- a/tools/perf/builtin-config.c
+++ b/tools/perf/builtin-config.c
@@ -32,13 +32,148 @@ static struct option config_options[] = {
 	OPT_END()
 };
 
-static int show_config(const char *key, const char *value,
-		       void *cb __maybe_unused)
+static struct config_section *find_section(struct list_head *sections,
+					   const char *section_name)
 {
+	struct config_section *section;
+
+	list_for_each_entry(section, sections, list)
+		if (!strcmp(section->name, section_name))
+			return section;
+
+	return NULL;
+}
+
+static struct config_element *find_element(const char *name,
+					   struct config_section *section)
+{
+	struct config_element *element;
+
+	list_for_each_entry(element, &section->element_head, list)
+		if (!strcmp(element->name, name))
+			return element;
+
+	return NULL;
+}
+
+static void find_config(struct list_head *sections,
+			struct config_section **section,
+			struct config_element **element,
+			const char *section_name, const char *name)
+{
+	*section = find_section(sections, section_name);
+
+	if (*section != NULL)
+		*element = find_element(name, *section);
+	else
+		*element = NULL;
+}
+
+static struct config_section *init_section(const char *section_name)
+{
+	struct config_section *section;
+
+	section = zalloc(sizeof(*section));
+	if (!section)
+		return NULL;
+
+	INIT_LIST_HEAD(&section->element_head);
+	section->name = strdup(section_name);
+	if (!section->name) {
+		pr_err("%s: strdup failed\n", __func__);
+		free(section);
+		return NULL;
+	}
+
+	return section;
+}
+
+static int add_element(struct list_head *head,
+			      const char *name, const char *value)
+{
+	struct config_element *element;
+
+	element = zalloc(sizeof(*element));
+	if (!element)
+		return -1;
+
+	element->name = strdup(name);
+	if (!element->name) {
+		pr_err("%s: strdup failed\n", __func__);
+		free(element);
+		return -1;
+	}
 	if (value)
-		printf("%s=%s\n", key, value);
+		element->value = (char *)value;
 	else
-		printf("%s\n", key);
+		element->value = NULL;
+
+	list_add_tail(&element->list, head);
+	return 0;
+}
+
+static int collect_current_config(const char *var, const char *value,
+				  void *spec_sections)
+{
+	int ret = -1;
+	char *ptr, *key;
+	char *section_name, *name;
+	struct config_section *section = NULL;
+	struct config_element *element = NULL;
+	struct list_head *sections = (struct list_head *)spec_sections;
+
+	key = ptr = strdup(var);
+	if (!key) {
+		pr_err("%s: strdup failed\n", __func__);
+		return -1;
+	}
+
+	section_name = strsep(&ptr, ".");
+	name = ptr;
+	if (name == NULL || value == NULL)
+		goto out_err;
+
+	find_config(sections, &section, &element, section_name, name);
+
+	if (!section) {
+		section = init_section(section_name);
+		if (!section)
+			goto out_err;
+		list_add_tail(&section->list, sections);
+	}
+
+	value = strdup(value);
+	if (!value) {
+		pr_err("%s: strdup failed\n", __func__);
+		goto out_err;
+	}
+
+	if (!element)
+		add_element(&section->element_head, name, value);
+	else {
+		free(element->value);
+		element->value = (char *)value;
+	}
+
+	ret = 0;
+out_err:
+	free(key);
+	return ret;
+}
+
+static int show_config(struct list_head *sections)
+{
+	struct config_section *section;
+	struct config_element *element;
+
+	if (list_empty(sections))
+		return -1;
+	list_for_each_entry(section, sections, list) {
+		list_for_each_entry(element, &section->element_head, list) {
+			printf("%s.%s=%s\n", section->name,
+				       element->name, element->value);
+		}
+	}
 
 	return 0;
 }
@@ -46,6 +181,7 @@ static int show_config(const char *key, const char *value,
 int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
 {
 	int ret = 0;
+	struct list_head sections;
 	char *user_config = mkpath("%s/.perfconfig", getenv("HOME"));
 
 	argc = parse_options(argc, argv, config_options, config_usage,
@@ -58,18 +194,22 @@ int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
 		return -1;
 	}
 
+	INIT_LIST_HEAD(&sections);
+
 	if (use_system_config)
 		config_exclusive_filename = perf_etc_perfconfig();
 	else if (use_user_config)
 		config_exclusive_filename = user_config;
 
+	perf_config(collect_current_config, &sections);
+
 	switch (actions) {
 	case ACTION_LIST:
 		if (argc) {
 			pr_err("Error: takes no arguments\n");
 			parse_options_usage(config_usage, config_options, "l", 1);
 		} else {
-			ret = perf_config(show_config, NULL);
+			ret = show_config(&sections);
 			if (ret < 0) {
 				const char * config_filename = config_exclusive_filename;
 				if (!config_exclusive_filename)
diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
index 3ca453f..92cd739 100644
--- a/tools/perf/util/cache.h
+++ b/tools/perf/util/cache.h
@@ -1,6 +1,7 @@
 #ifndef __PERF_CACHE_H
 #define __PERF_CACHE_H
 
+#include <linux/list.h>
 #include <stdbool.h>
 #include "util.h"
 #include "strbuf.h"
@@ -23,6 +24,18 @@
 #define PERF_TRACEFS_ENVIRONMENT "PERF_TRACEFS_DIR"
 #define PERF_PAGER_ENVIRONMENT "PERF_PAGER"
 
+struct config_element {
+	char *name;
+	char *value;
+	struct list_head list;
+};
+
+struct config_section {
+	char *name;
+	struct list_head element_head;
+	struct list_head list;
+};
+
 extern const char *config_exclusive_filename;
 
 typedef int (*config_fn_t)(const char *, const char *, void *);
-- 
2.5.0