root/tools/perf/builtin-config.c
// SPDX-License-Identifier: GPL-2.0
/*
 * builtin-config.c
 *
 * Copyright (C) 2015, Taeung Song <treeze.taeung@gmail.com>
 *
 */
#include "builtin.h"

#include "util/cache.h"
#include <subcmd/parse-options.h>
#include "util/debug.h"
#include "util/config.h"
#include <linux/string.h>
#include <limits.h>
#include <stdio.h>
#include <stdlib.h>

static bool use_system_config, use_user_config;

static const char * const config_usage[] = {
        "perf config [<file-option>] [options] [section.name[=value] ...]",
        NULL
};

enum actions {
        ACTION_LIST = 1
} actions;

static struct option config_options[] = {
        OPT_SET_UINT('l', "list", &actions,
                     "show current config variables", ACTION_LIST),
        OPT_BOOLEAN(0, "system", &use_system_config, "use system config file"),
        OPT_BOOLEAN(0, "user", &use_user_config, "use user config file"),
        OPT_END()
};

static int set_config(struct perf_config_set *set, const char *file_name)
{
        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;

        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 && item->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 (!strstarts(var, section->name))
                        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;
        struct perf_config_item *item;

        if (set == NULL)
                return -1;

        perf_config_set__for_each_entry(set, section, item) {
                char *value = item->value;

                if (value)
                        printf("%s.%s=%s\n", section->name,
                               item->name, value);
        }

        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 perf_config__set_variable(const char *var, const char *value)
{
        char path[PATH_MAX];
        char *user_config = mkpath(path, sizeof(path), "%s/.perfconfig", getenv("HOME"));
        const char *config_filename;
        struct perf_config_set *set;
        int ret = -1;

        if (use_system_config)
                config_exclusive_filename = perf_etc_perfconfig();
        else if (use_user_config)
                config_exclusive_filename = user_config;

        if (!config_exclusive_filename)
                config_filename = user_config;
        else
                config_filename = config_exclusive_filename;

        set = perf_config_set__new();
        if (!set)
                goto out_err;

        if (perf_config_set__collect(set, config_filename, var, value) < 0) {
                pr_err("Failed to add '%s=%s'\n", var, value);
                goto out_err;
        }

        if (set_config(set, config_filename) < 0) {
                pr_err("Failed to set the configs on %s\n", config_filename);
                goto out_err;
        }

        ret = 0;
out_err:
        perf_config_set__delete(set);
        return ret;
}

int cmd_config(int argc, const char **argv)
{
        int i, ret = -1;
        struct perf_config_set *set;
        char path[PATH_MAX];
        char *user_config = mkpath(path, sizeof(path), "%s/.perfconfig", getenv("HOME"));
        const char *config_filename;
        bool changed = false;

        argc = parse_options(argc, argv, config_options, config_usage,
                             PARSE_OPT_STOP_AT_NON_OPTION);

        if (use_system_config && use_user_config) {
                pr_err("Error: only one config file at a time\n");
                parse_options_usage(config_usage, config_options, "user", 0);
                parse_options_usage(NULL, config_options, "system", 0);
                return -1;
        }

        if (use_system_config)
                config_exclusive_filename = perf_etc_perfconfig();
        else if (use_user_config)
                config_exclusive_filename = user_config;

        if (!config_exclusive_filename)
                config_filename = user_config;
        else
                config_filename = config_exclusive_filename;

        /*
         * At only 'config' sub-command, individually use the config set
         * because of reinitializing with options config file location.
         */
        set = perf_config_set__new();
        if (!set)
                goto out_err;

        switch (actions) {
        case ACTION_LIST:
                if (argc) {
                        pr_err("Error: takes no arguments\n");
                        parse_options_usage(config_usage, config_options, "l", 1);
                } else {
do_action_list:
                        if (show_config(set) < 0) {
                                pr_err("Nothing configured, "
                                       "please check your %s \n", config_filename);
                                goto out_err;
                        }
                }
                break;
        default:
                if (!argc)
                        goto do_action_list;

                for (i = 0; argv[i]; i++) {
                        char *var, *value;
                        char *arg = strdup(argv[i]);

                        if (!arg) {
                                pr_err("%s: strdup failed\n", __func__);
                                goto out_err;
                        }

                        if (parse_config_arg(arg, &var, &value) < 0) {
                                free(arg);
                                goto out_err;
                        }

                        if (value == NULL) {
                                if (show_spec_config(set, var) < 0) {
                                        pr_err("%s is not configured: %s\n",
                                               var, config_filename);
                                        free(arg);
                                        goto out_err;
                                }
                        } else {
                                if (perf_config_set__collect(set, config_filename,
                                                             var, value) < 0) {
                                        pr_err("Failed to add '%s=%s'\n",
                                               var, value);
                                        free(arg);
                                        goto out_err;
                                }
                                changed = true;
                        }
                        free(arg);
                }

                if (!changed)
                        break;

                if (set_config(set, config_filename) < 0) {
                        pr_err("Failed to set the configs on %s\n",
                               config_filename);
                        goto out_err;
                }
        }

        ret = 0;
out_err:
        perf_config_set__delete(set);
        return ret;
}