// SPDX-License-Identifier: GPL-2.0
/*
 * config.c
 *
 * Helper functions for parsing config items.
 * Originally copied from GIT source.
 *
 * Copyright (C) Linus Torvalds, 2005
 * Copyright (C) Johannes Schindelin, 2005
 *
 */
#include <errno.h>
#include <sys/param.h>
#include "cache.h"
#include "callchain.h"
#include "header.h"
#include <subcmd/exec-cmd.h>
#include "util/event.h"  /* proc_map_timeout */
#include "util/hist.h"  /* perf_hist_config */
#include "util/stat.h"  /* perf_stat__set_big_num */
#include "util/evsel.h"  /* evsel__hw_names, evsel__use_bpf_counters */
#include "util/addr2line.h"  /* addr2line_timeout_ms */
#include "srcline.h"
#include "build-id.h"
#include "debug.h"
#include "config.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <unistd.h>
#include <linux/string.h>
#include <linux/zalloc.h>
#include <linux/ctype.h>

#define MAXNAME (256)

#define DEBUG_CACHE_DIR ".debug"

#define METRIC_ONLY_LEN 20

static struct stats walltime_nsecs_stats;

struct perf_stat_config stat_config = {
        .aggr_mode              = AGGR_GLOBAL,
        .aggr_level             = MAX_CACHE_LVL + 1,
        .scale                  = true,
        .unit_width             = 4, /* strlen("unit") */
        .run_count              = 1,
        .metric_only_len        = METRIC_ONLY_LEN,
        .walltime_nsecs_stats   = &walltime_nsecs_stats,
        .big_num                = true,
        .ctl_fd                 = -1,
        .ctl_fd_ack             = -1,
        .iostat_run             = false,
};

char buildid_dir[MAXPATHLEN]; /* root dir for buildid, binary cache */

static FILE *config_file;
static const char *config_file_name;
static int config_linenr;
static int config_file_eof;
static struct perf_config_set *config_set;

const char *config_exclusive_filename;

static int get_next_char(void)
{
        int c;
        FILE *f;

        c = '\n';
        if ((f = config_file) != NULL) {
                c = fgetc(f);
                if (c == '\r') {
                        /* DOS like systems */
                        c = fgetc(f);
                        if (c != '\n') {
                                ungetc(c, f);
                                c = '\r';
                        }
                }
                if (c == '\n')
                        config_linenr++;
                if (c == EOF) {
                        config_file_eof = 1;
                        c = '\n';
                }
        }
        return c;
}

static char *parse_value(void)
{
        static char value[1024];
        int quote = 0, comment = 0, space = 0;
        size_t len = 0;

        for (;;) {
                int c = get_next_char();

                if (len >= sizeof(value) - 1)
                        return NULL;
                if (c == '\n') {
                        if (quote)
                                return NULL;
                        value[len] = 0;
                        return value;
                }
                if (comment)
                        continue;
                if (isspace(c) && !quote) {
                        space = 1;
                        continue;
                }
                if (!quote) {
                        if (c == ';' || c == '#') {
                                comment = 1;
                                continue;
                        }
                }
                if (space) {
                        if (len)
                                value[len++] = ' ';
                        space = 0;
                }
                if (c == '\\') {
                        c = get_next_char();
                        switch (c) {
                        case '\n':
                                continue;
                        case 't':
                                c = '\t';
                                break;
                        case 'b':
                                c = '\b';
                                break;
                        case 'n':
                                c = '\n';
                                break;
                        /* Some characters escape as themselves */
                        case '\\': case '"':
                                break;
                        /* Reject unknown escape sequences */
                        default:
                                return NULL;
                        }
                        value[len++] = c;
                        continue;
                }
                if (c == '"') {
                        quote = 1-quote;
                        continue;
                }
                value[len++] = c;
        }
}

static inline int iskeychar(int c)
{
        return isalnum(c) || c == '-' || c == '_';
}

static int get_value(config_fn_t fn, void *data, char *name, unsigned int len)
{
        int c;
        char *value;

        /* Get the full name */
        for (;;) {
                c = get_next_char();
                if (config_file_eof)
                        break;
                if (!iskeychar(c))
                        break;
                name[len++] = c;
                if (len >= MAXNAME)
                        return -1;
        }
        name[len] = 0;
        while (c == ' ' || c == '\t')
                c = get_next_char();

        value = NULL;
        if (c != '\n') {
                if (c != '=')
                        return -1;
                value = parse_value();
                if (!value)
                        return -1;
        }
        return fn(name, value, data);
}

static int get_extended_base_var(char *name, int baselen, int c)
{
        do {
                if (c == '\n')
                        return -1;
                c = get_next_char();
        } while (isspace(c));

        /* We require the format to be '[base "extension"]' */
        if (c != '"')
                return -1;
        name[baselen++] = '.';

        for (;;) {
                int ch = get_next_char();

                if (ch == '\n')
                        return -1;
                if (ch == '"')
                        break;
                if (ch == '\\') {
                        ch = get_next_char();
                        if (ch == '\n')
                                return -1;
                }
                name[baselen++] = ch;
                if (baselen > MAXNAME / 2)
                        return -1;
        }

        /* Final ']' */
        if (get_next_char() != ']')
                return -1;
        return baselen;
}

static int get_base_var(char *name)
{
        int baselen = 0;

        for (;;) {
                int c = get_next_char();
                if (config_file_eof)
                        return -1;
                if (c == ']')
                        return baselen;
                if (isspace(c))
                        return get_extended_base_var(name, baselen, c);
                if (!iskeychar(c) && c != '.')
                        return -1;
                if (baselen > MAXNAME / 2)
                        return -1;
                name[baselen++] = tolower(c);
        }
}

static int perf_parse_file(config_fn_t fn, void *data)
{
        int comment = 0;
        int baselen = 0;
        static char var[MAXNAME];

        /* U+FEFF Byte Order Mark in UTF8 */
        static const unsigned char *utf8_bom = (unsigned char *) "\xef\xbb\xbf";
        const unsigned char *bomptr = utf8_bom;

        for (;;) {
                int line, c = get_next_char();

                if (bomptr && *bomptr) {
                        /* We are at the file beginning; skip UTF8-encoded BOM
                         * if present. Sane editors won't put this in on their
                         * own, but e.g. Windows Notepad will do it happily. */
                        if ((unsigned char) c == *bomptr) {
                                bomptr++;
                                continue;
                        } else {
                                /* Do not tolerate partial BOM. */
                                if (bomptr != utf8_bom)
                                        break;
                                /* No BOM at file beginning. Cool. */
                                bomptr = NULL;
                        }
                }
                if (c == '\n') {
                        if (config_file_eof)
                                return 0;
                        comment = 0;
                        continue;
                }
                if (comment || isspace(c))
                        continue;
                if (c == '#' || c == ';') {
                        comment = 1;
                        continue;
                }
                if (c == '[') {
                        baselen = get_base_var(var);
                        if (baselen <= 0)
                                break;
                        var[baselen++] = '.';
                        var[baselen] = 0;
                        continue;
                }
                if (!isalpha(c))
                        break;
                var[baselen] = tolower(c);

                /*
                 * The get_value function might or might not reach the '\n',
                 * so saving the current line number for error reporting.
                 */
                line = config_linenr;
                if (get_value(fn, data, var, baselen+1) < 0) {
                        config_linenr = line;
                        break;
                }
        }
        pr_err("bad config file line %d in %s\n", config_linenr, config_file_name);
        return -1;
}

static int parse_unit_factor(const char *end, unsigned long *val)
{
        if (!*end)
                return 1;
        else if (!strcasecmp(end, "k")) {
                *val *= 1024;
                return 1;
        }
        else if (!strcasecmp(end, "m")) {
                *val *= 1024 * 1024;
                return 1;
        }
        else if (!strcasecmp(end, "g")) {
                *val *= 1024 * 1024 * 1024;
                return 1;
        }
        return 0;
}

static int perf_parse_llong(const char *value, long long *ret)
{
        if (value && *value) {
                char *end;
                long long val = strtoll(value, &end, 0);
                unsigned long factor = 1;

                if (!parse_unit_factor(end, &factor))
                        return 0;
                *ret = val * factor;
                return 1;
        }
        return 0;
}

static int perf_parse_long(const char *value, long *ret)
{
        if (value && *value) {
                char *end;
                long val = strtol(value, &end, 0);
                unsigned long factor = 1;
                if (!parse_unit_factor(end, &factor))
                        return 0;
                *ret = val * factor;
                return 1;
        }
        return 0;
}

static void bad_config(const char *name)
{
        if (config_file_name)
                pr_warning("bad config value for '%s' in %s, ignoring...\n", name, config_file_name);
        else
                pr_warning("bad config value for '%s', ignoring...\n", name);
}

int perf_config_u64(u64 *dest, const char *name, const char *value)
{
        long long ret = 0;

        if (!perf_parse_llong(value, &ret)) {
                bad_config(name);
                return -1;
        }

        *dest = ret;
        return 0;
}

int perf_config_int(int *dest, const char *name, const char *value)
{
        long ret = 0;
        if (!perf_parse_long(value, &ret)) {
                bad_config(name);
                return -1;
        }
        *dest = ret;
        return 0;
}

int perf_config_u8(u8 *dest, const char *name, const char *value)
{
        long ret = 0;

        if (!perf_parse_long(value, &ret)) {
                bad_config(name);
                return -1;
        }
        *dest = ret;
        return 0;
}

static int perf_config_bool_or_int(const char *name, const char *value, int *is_bool)
{
        int ret;

        *is_bool = 1;
        if (!value)
                return 1;
        if (!*value)
                return 0;
        if (!strcasecmp(value, "true") || !strcasecmp(value, "yes") || !strcasecmp(value, "on"))
                return 1;
        if (!strcasecmp(value, "false") || !strcasecmp(value, "no") || !strcasecmp(value, "off"))
                return 0;
        *is_bool = 0;
        return perf_config_int(&ret, name, value) < 0 ? -1 : ret;
}

int perf_config_bool(const char *name, const char *value)
{
        int discard;
        return !!perf_config_bool_or_int(name, value, &discard);
}

static const char *perf_config_dirname(const char *name, const char *value)
{
        if (!name)
                return NULL;
        return value;
}

static int perf_buildid_config(const char *var, const char *value)
{
        /* same dir for all commands */
        if (!strcmp(var, "buildid.dir")) {
                const char *dir = perf_config_dirname(var, value);

                if (!dir) {
                        pr_err("Invalid buildid directory!\n");
                        return -1;
                }
                strncpy(buildid_dir, dir, MAXPATHLEN-1);
                buildid_dir[MAXPATHLEN-1] = '\0';
        }

        return 0;
}

static int perf_default_core_config(const char *var, const char *value)
{
        if (!strcmp(var, "core.proc-map-timeout"))
                proc_map_timeout = strtoul(value, NULL, 10);

        if (!strcmp(var, "core.addr2line-timeout"))
                addr2line_timeout_ms = strtoul(value, NULL, 10);

        /* Add other config variables here. */
        return 0;
}

static int perf_ui_config(const char *var, const char *value)
{
        /* Add other config variables here. */
        if (!strcmp(var, "ui.show-headers"))
                symbol_conf.show_hist_headers = perf_config_bool(var, value);

        return 0;
}

void perf_stat__set_big_num(int set)
{
        stat_config.big_num = (set != 0);
}

static void perf_stat__set_no_csv_summary(int set)
{
        stat_config.no_csv_summary = (set != 0);
}

static int perf_stat_config(const char *var, const char *value)
{
        if (!strcmp(var, "stat.big-num"))
                perf_stat__set_big_num(perf_config_bool(var, value));

        if (!strcmp(var, "stat.no-csv-summary"))
                perf_stat__set_no_csv_summary(perf_config_bool(var, value));

        if (!strcmp(var, "stat.bpf-counter-events"))
                evsel__bpf_counter_events = strdup(value);

        /* Add other config variables here. */
        return 0;
}

int perf_default_config(const char *var, const char *value,
                        void *dummy __maybe_unused)
{
        if (strstarts(var, "core."))
                return perf_default_core_config(var, value);

        if (strstarts(var, "hist."))
                return perf_hist_config(var, value);

        if (strstarts(var, "ui."))
                return perf_ui_config(var, value);

        if (strstarts(var, "call-graph."))
                return perf_callchain_config(var, value);

        if (strstarts(var, "buildid."))
                return perf_buildid_config(var, value);

        if (strstarts(var, "stat."))
                return perf_stat_config(var, value);

        if (strstarts(var, "addr2line."))
                return addr2line_configure(var, value, dummy);

        /* Add other config variables here. */
        return 0;
}

static int perf_config_from_file(config_fn_t fn, const char *filename, void *data)
{
        int ret;
        FILE *f = fopen(filename, "r");

        ret = -1;
        if (f) {
                config_file = f;
                config_file_name = filename;
                config_linenr = 1;
                config_file_eof = 0;
                ret = perf_parse_file(fn, data);
                fclose(f);
                config_file_name = NULL;
        }
        return ret;
}

const char *perf_etc_perfconfig(void)
{
        static const char *system_wide;
        if (!system_wide)
                system_wide = system_path(ETC_PERFCONFIG);
        return system_wide;
}

static int perf_env_bool(const char *k, int def)
{
        const char *v = getenv(k);
        return v ? perf_config_bool(k, v) : def;
}

int perf_config_system(void)
{
        return !perf_env_bool("PERF_CONFIG_NOSYSTEM", 0);
}

int perf_config_global(void)
{
        return !perf_env_bool("PERF_CONFIG_NOGLOBAL", 0);
}

static char *home_perfconfig(void)
{
        const char *home = NULL;
        char *config;
        struct stat st;
        char path[PATH_MAX];

        home = getenv("HOME");

        /*
         * Skip reading user config if:
         *   - there is no place to read it from (HOME)
         *   - we are asked not to (PERF_CONFIG_NOGLOBAL=1)
         */
        if (!home || !*home || !perf_config_global())
                return NULL;

        config = strdup(mkpath(path, sizeof(path), "%s/.perfconfig", home));
        if (config == NULL) {
                pr_warning("Not enough memory to process %s/.perfconfig, ignoring it.\n", home);
                return NULL;
        }

        if (stat(config, &st) < 0)
                goto out_free;

        if (st.st_uid && (st.st_uid != geteuid())) {
                pr_warning("File %s not owned by current user or root, ignoring it.\n", config);
                goto out_free;
        }

        if (st.st_size)
                return config;

out_free:
        free(config);
        return NULL;
}

const char *perf_home_perfconfig(void)
{
        static const char *config;
        static bool failed;

        if (failed || config)
                return config;

        config = home_perfconfig();
        if (!config)
                failed = true;

        return config;
}

static struct perf_config_section *find_section(struct list_head *sections,
                                                const char *section_name)
{
        struct perf_config_section *section;

        list_for_each_entry(section, sections, node)
                if (!strcmp(section->name, section_name))
                        return section;

        return NULL;
}

static struct perf_config_item *find_config_item(const char *name,
                                                 struct perf_config_section *section)
{
        struct perf_config_item *item;

        list_for_each_entry(item, &section->items, node)
                if (!strcmp(item->name, name))
                        return item;

        return NULL;
}

static struct perf_config_section *add_section(struct list_head *sections,
                                               const char *section_name)
{
        struct perf_config_section *section = zalloc(sizeof(*section));

        if (!section)
                return NULL;

        INIT_LIST_HEAD(&section->items);
        section->name = strdup(section_name);
        if (!section->name) {
                pr_debug("%s: strdup failed\n", __func__);
                free(section);
                return NULL;
        }

        list_add_tail(&section->node, sections);
        return section;
}

static struct perf_config_item *add_config_item(struct perf_config_section *section,
                                                const char *name)
{
        struct perf_config_item *item = zalloc(sizeof(*item));

        if (!item)
                return NULL;

        item->name = strdup(name);
        if (!item->name) {
                pr_debug("%s: strdup failed\n", __func__);
                free(item);
                return NULL;
        }

        list_add_tail(&item->node, &section->items);
        return item;
}

static int set_value(struct perf_config_item *item, const char *value)
{
        char *val = strdup(value);

        if (!val)
                return -1;

        zfree(&item->value);
        item->value = val;
        return 0;
}

static int collect_config(const char *var, const char *value,
                          void *perf_config_set)
{
        int ret = -1;
        char *ptr, *key;
        char *section_name, *name;
        struct perf_config_section *section = NULL;
        struct perf_config_item *item = NULL;
        struct perf_config_set *set = perf_config_set;
        struct list_head *sections;

        if (set == NULL)
                return -1;

        sections = &set->sections;
        key = ptr = strdup(var);
        if (!key) {
                pr_debug("%s: strdup failed\n", __func__);
                return -1;
        }

        section_name = strsep(&ptr, ".");
        name = ptr;
        if (name == NULL || value == NULL)
                goto out_free;

        section = find_section(sections, section_name);
        if (!section) {
                section = add_section(sections, section_name);
                if (!section)
                        goto out_free;
        }

        item = find_config_item(name, section);
        if (!item) {
                item = add_config_item(section, name);
                if (!item)
                        goto out_free;
        }

        /* perf_config_set can contain both user and system config items.
         * So we should know where each value is from.
         * The classification would be needed when a particular config file
         * is overwritten by setting feature i.e. set_config().
         */
        if (strcmp(config_file_name, perf_etc_perfconfig()) == 0) {
                section->from_system_config = true;
                item->from_system_config = true;
        } else {
                section->from_system_config = false;
                item->from_system_config = false;
        }

        ret = set_value(item, value);

out_free:
        free(key);
        return ret;
}

int perf_config_set__collect(struct perf_config_set *set, const char *file_name,
                             const char *var, const char *value)
{
        config_file_name = file_name;
        return collect_config(var, value, set);
}

static int perf_config_set__init(struct perf_config_set *set)
{
        int ret = -1;

        /* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
        if (config_exclusive_filename)
                return perf_config_from_file(collect_config, config_exclusive_filename, set);
        if (perf_config_system() && !access(perf_etc_perfconfig(), R_OK)) {
                if (perf_config_from_file(collect_config, perf_etc_perfconfig(), set) < 0)
                        goto out;
        }
        if (perf_config_global() && perf_home_perfconfig()) {
                if (perf_config_from_file(collect_config, perf_home_perfconfig(), set) < 0)
                        goto out;
        }

out:
        return ret;
}

struct perf_config_set *perf_config_set__new(void)
{
        struct perf_config_set *set = zalloc(sizeof(*set));

        if (set) {
                INIT_LIST_HEAD(&set->sections);
                perf_config_set__init(set);
        }

        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)
                config_set = perf_config_set__new();

        return config_set == NULL;
}

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;

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

                if (value) {
                        scnprintf(key, sizeof(key), "%s.%s",
                                  section->name, item->name);
                        ret = fn(key, value, data);
                        if (ret < 0) {
                                pr_err("Error in the given config file: wrong config key-value pair %s=%s\n",
                                       key, value);
                                /*
                                 * Can't be just a 'break', as perf_config_set__for_each_entry()
                                 * expands to two nested for() loops.
                                 */
                                goto out;
                        }
                }
        }
out:
        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);
        config_set = NULL;
}

static void perf_config_item__delete(struct perf_config_item *item)
{
        zfree(&item->name);
        zfree(&item->value);
        free(item);
}

static void perf_config_section__purge(struct perf_config_section *section)
{
        struct perf_config_item *item, *tmp;

        list_for_each_entry_safe(item, tmp, &section->items, node) {
                list_del_init(&item->node);
                perf_config_item__delete(item);
        }
}

static void perf_config_section__delete(struct perf_config_section *section)
{
        perf_config_section__purge(section);
        zfree(&section->name);
        free(section);
}

static void perf_config_set__purge(struct perf_config_set *set)
{
        struct perf_config_section *section, *tmp;

        list_for_each_entry_safe(section, tmp, &set->sections, node) {
                list_del_init(&section->node);
                perf_config_section__delete(section);
        }
}

void perf_config_set__delete(struct perf_config_set *set)
{
        if (set == NULL)
                return;

        perf_config_set__purge(set);
        free(set);
}

/*
 * Call this to report error for your variable that should not
 * get a boolean value (i.e. "[my] var" means "true").
 */
int config_error_nonbool(const char *var)
{
        pr_err("Missing value for '%s'", var);
        return -1;
}

void set_buildid_dir(const char *dir)
{
        if (dir)
                scnprintf(buildid_dir, MAXPATHLEN, "%s", dir);

        /* default to $HOME/.debug */
        if (buildid_dir[0] == '\0') {
                char *home = getenv("HOME");

                if (home) {
                        snprintf(buildid_dir, MAXPATHLEN, "%s/%s",
                                 home, DEBUG_CACHE_DIR);
                } else {
                        strncpy(buildid_dir, DEBUG_CACHE_DIR, MAXPATHLEN-1);
                }
                buildid_dir[MAXPATHLEN-1] = '\0';
        }
        /* for communicating with external commands */
        setenv("PERF_BUILDID_DIR", buildid_dir, 1);
}

struct perf_config_scan_data {
        const char *name;
        const char *fmt;
        const char *value;
        va_list args;
        int ret;
};

static int perf_config_scan_cb(const char *var, const char *value, void *data)
{
        struct perf_config_scan_data *d = data;

        if (!strcmp(var, d->name))
                d->ret = vsscanf(value, d->fmt, d->args);

        return 0;
}

int perf_config_scan(const char *name, const char *fmt, ...)
{
        struct perf_config_scan_data d = {
                .name = name,
                .fmt = fmt,
        };

        va_start(d.args, fmt);
        perf_config(perf_config_scan_cb, &d);
        va_end(d.args);

        return d.ret;
}

static int perf_config_get_cb(const char *var, const char *value, void *data)
{
        struct perf_config_scan_data *d = data;

        if (!strcmp(var, d->name))
                d->value = value;

        return 0;
}

const char *perf_config_get(const char *name)
{
        struct perf_config_scan_data d = {
                .name = name,
                .value = NULL,
        };

        perf_config(perf_config_get_cb, &d);
        return d.value;
}