1 files changed, 134 insertions, 3 deletions

diff --git a/tools/perf/builtin-config.c b/tools/perf/builtin-config.c
index e4207a23b52c..8c0d93b7c2f0 100644
--- a/tools/perf/builtin-config.c
+++ b/tools/perf/builtin-config.c
@@ -17,7 +17,7 @@
 static bool use_system_config, use_user_config;
 
 static const char * const config_usage[] = {
-	"perf config [<file-option>] [options]",
+	"perf config [<file-option>] [options] [section.name[=value] ...]",
 	NULL
 };
 
@@ -33,6 +33,73 @@ static struct option config_options[] = {
 	OPT_END()
 };
 
+static int set_config(struct perf_config_set *set, const char *file_name,
+		      const char *var, const char *value)
+{
+	struct perf_config_section *section = NULL;
+	struct perf_config_item *item = NULL;
+	const char *first_line = "# this file is auto-generated.";
+	FILE *fp;
+
+	if (set == NULL)
+		return -1;
+
+	fp = fopen(file_name, "w");
+	if (!fp)
+		return -1;
+
+	perf_config_set__collect(set, file_name, var, value);
+	fprintf(fp, "%s\n", first_line);
+
+	/* overwrite configvariables */
+	perf_config_items__for_each_entry(&set->sections, section) {
+		if (!use_system_config && section->from_system_config)
+			continue;
+		fprintf(fp, "[%s]\n", section->name);
+
+		perf_config_items__for_each_entry(&section->items, item) {
+			if (!use_system_config && section->from_system_config)
+				continue;
+			if (item->value)
+				fprintf(fp, "\t%s = %s\n",
+					item->name, item->value);
+		}
+	}
+	fclose(fp);
+
+	return 0;
+}
+
+static int show_spec_config(struct perf_config_set *set, const char *var)
+{
+	struct perf_config_section *section;
+	struct perf_config_item *item;
+
+	if (set == NULL)
+		return -1;
+
+	perf_config_items__for_each_entry(&set->sections, section) {
+		if (prefixcmp(var, section->name) != 0)
+			continue;
+
+		perf_config_items__for_each_entry(&section->items, item) {
+			const char *name = var + strlen(section->name) + 1;
+
+			if (strcmp(name, item->name) == 0) {
+				char *value = item->value;
+
+				if (value) {
+					printf("%s=%s\n", var, value);
+					return 0;
+				}
+			}
+
+		}
+	}
+
+	return 0;
+}
+
 static int show_config(struct perf_config_set *set)
 {
 	struct perf_config_section *section;
@@ -52,9 +119,44 @@ static int show_config(struct perf_config_set *set)
 	return 0;
 }
 
+static int parse_config_arg(char *arg, char **var, char **value)
+{
+	const char *last_dot = strchr(arg, '.');
+
+	/*
+	 * Since "var" actually contains the section name and the real
+	 * config variable name separated by a dot, we have to know where the dot is.
+	 */
+	if (last_dot == NULL || last_dot == arg) {
+		pr_err("The config variable does not contain a section name: %s\n", arg);
+		return -1;
+	}
+	if (!last_dot[1]) {
+		pr_err("The config variable does not contain a variable name: %s\n", arg);
+		return -1;
+	}
+
+	*value = strchr(arg, '=');
+	if (*value == NULL)
+		*var = arg;
+	else if (!strcmp(*value, "=")) {
+		pr_err("The config variable does not contain a value: %s\n", arg);
+		return -1;
+	} else {
+		*value = *value + 1; /* excluding a first character '=' */
+		*var = strsep(&arg, "=");
+		if (*var[0] == '\0') {
+			pr_err("invalid config variable: %s\n", arg);
+			return -1;
+		}
+	}
+
+	return 0;
+}
+
 int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
 {
-	int ret = 0;
+	int i, ret = 0;
 	struct perf_config_set *set;
 	char *user_config = mkpath("%s/.perfconfig", getenv("HOME"));
 
@@ -100,7 +202,36 @@ int cmd_config(int argc, const char **argv, const char *prefix __maybe_unused)
 		}
 		break;
 	default:
-		usage_with_options(config_usage, config_options);
+		if (argc) {
+			for (i = 0; argv[i]; i++) {
+				char *var, *value;
+				char *arg = strdup(argv[i]);
+
+				if (!arg) {
+					pr_err("%s: strdup failed\n", __func__);
+					ret = -1;
+					break;
+				}
+
+				if (parse_config_arg(arg, &var, &value) < 0) {
+					free(arg);
+					ret = -1;
+					break;
+				}
+
+				if (value == NULL)
+					ret = show_spec_config(set, var);
+				else {
+					const char *config_filename = config_exclusive_filename;
+
+					if (!config_exclusive_filename)
+						config_filename = user_config;
+					ret = set_config(set, config_filename, var, value);
+				}
+				free(arg);
+			}
+		} else
+			usage_with_options(config_usage, config_options);
 	}
 
 	perf_config_set__delete(set);