[PATCH v4 2/5] perf config: Add '--system' and '--global' options to be able to select which config file to be used

[Taeung Song <treeze.taeung@gmail.com>]

Which config file is used is decided in only perf_config().
And a perf-confg command depend on perf_config()
getting config file path. So add '--system' and '--global' options
to select which config file to be used without perf_config().
If file-options isn't used, default config file path is
$HOME/.perfconfig.

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
---
 tools/perf/Documentation/perf-config.txt | 14 +++++++++++++-
 tools/perf/builtin-config.c              | 21 ++++++++++++++++++---
 tools/perf/util/cache.h                  |  2 ++
 tools/perf/util/config.c                 |  4 ++--
 4 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-config.txt b/tools/perf/Documentation/perf-config.txt
index 1a339ea..f1e50b3 100644
--- a/tools/perf/Documentation/perf-config.txt
+++ b/tools/perf/Documentation/perf-config.txt
@@ -8,7 +8,7 @@ perf-config - Get and set variables in a configuration file.
 SYNOPSIS
 --------
 [verse]
-'perf config' -l | --list
+'perf config' [<file-option>] -l | --list
 
 DESCRIPTION
 -----------
@@ -21,6 +21,14 @@ OPTIONS
 --list::
 	Show current config variables with key and value into each sections.
 
+--global::
+	For writing and reading options: write to global
+	'$HOME/.perfconfig' file or read it.
+
+--system::
+	For writing and reading options: write to system-wide
+	'$(sysconfdir)/perfconfig' or read it.
+
 CONFIGURATION FILE
 ------------------
 
@@ -33,6 +41,10 @@ store a system-wide default configuration.
 The variables are divided into sections. In each section, the variables
 can are composed of a key and value.
 
+When reading or writing, the values are read from the system and  global
+configuration files by default, and options '--system' and '--global'
+can be used to tell the command to read from or write to only that location.
+
 Syntax
 ~~~~~~
 
diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index f0541b8..27609bd 100644
--- a/tools/perf/builtin-config.c
+++ b/tools/perf/builtin-config.c
@@ -14,6 +14,8 @@
 #include "util/debug.h"
 
 static int actions;
+static bool use_system_config, use_global_config;
+static const char *config_file_name;
 
 static const char * const config_usage[] = {
 	"perf config [options]",
@@ -23,6 +25,9 @@ static const char * const config_usage[] = {
 #define ACTION_LIST (1<<0)
 
 static const struct option config_options[] = {
+	OPT_GROUP("Config file location"),
+	OPT_BOOLEAN(0, "system", &use_system_config, "use system config file"),
+	OPT_BOOLEAN(0, "global", &use_global_config, "use global config file"),
 	OPT_GROUP("Action"),
 	OPT_BIT('l', "list", &actions,
 		"show current config variables", ACTION_LIST),
@@ -53,16 +58,26 @@ int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
 	else
 		has_option = false;
 
+	if (use_system_config && use_global_config) {
+		pr_err("Error: only one config file at a time\n");
+		usage_with_options(config_usage, config_options);
+		return -1;
+	} else if (use_global_config || (!use_system_config && !use_global_config))
+		config_file_name = mkpath("%s/.perfconfig", getenv("HOME"));
+	else if (use_system_config)
+		config_file_name = perf_etc_perfconfig();
+
 	switch (actions) {
 	case ACTION_LIST:
 		if (argc == 0)
-			ret = perf_config(show_config, NULL);
+			ret = perf_config_from_file(show_config, config_file_name, NULL);
 		else
 			goto out_err;
 		goto out;
 	default:
-		if (!has_option && argc == 0) {
-			ret = perf_config(show_config, NULL);
+		if ((!has_option || use_global_config || use_system_config)
+		    && argc == 0) {
+			ret = perf_config_from_file(show_config, config_file_name, NULL);
 			goto out;
 		} else
 			goto out_err;
diff --git a/tools/perf/util/cache.h b/tools/perf/util/cache.h
index c861373..bad3e4e 100644
--- a/tools/perf/util/cache.h
+++ b/tools/perf/util/cache.h
@@ -22,11 +22,13 @@
 typedef int (*config_fn_t)(const char *, const char *, void *);
 extern int perf_default_config(const char *, const char *, void *);
 extern int perf_config(config_fn_t fn, void *);
+extern int perf_config_from_file(config_fn_t fn, const char *filename, void *data);
 extern int perf_config_int(const char *, const char *);
 extern u64 perf_config_u64(const char *, const char *);
 extern int perf_config_bool(const char *, const char *);
 extern int config_error_nonbool(const char *);
 extern const char *perf_config_dirname(const char *, const char *);
+extern const char *perf_etc_perfconfig(void);
 
 /* pager.c */
 extern void setup_pager(void);
diff --git a/tools/perf/util/config.c b/tools/perf/util/config.c
index e18f653..1a9862f 100644
--- a/tools/perf/util/config.c
+++ b/tools/perf/util/config.c
@@ -412,7 +412,7 @@ int perf_default_config(const char *var, const char *value,
 	return 0;
 }
 
-static int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
+int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
 {
 	int ret;
 	FILE *f = fopen(filename, "r");
@@ -430,7 +430,7 @@ static int perf_config_from_file(config_fn_t fn, const char *filename, void *dat
 	return ret;
 }
 
-static const char *perf_etc_perfconfig(void)
+const char *perf_etc_perfconfig(void)
 {
 	static const char *system_wide;
 	if (!system_wide)
-- 
1.9.1