/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 * Copyright (C) Johannes Schindelin, 2005
 *
 */
#include "cache.h"
#include "config.h"
#include "repository.h"
#include "lockfile.h"
#include "exec-cmd.h"
#include "strbuf.h"
#include "quote.h"
#include "hashmap.h"
#include "string-list.h"
#include "object-store.h"
#include "utf8.h"
#include "dir.h"
#include "color.h"

struct config_source {
        struct config_source *prev;
        union {
                FILE *file;
                struct config_buf {
                        const char *buf;
                        size_t len;
                        size_t pos;
                } buf;
        } u;
        enum config_origin_type origin_type;
        const char *name;
        const char *path;
        enum config_error_action default_error_action;
        int linenr;
        int eof;
        struct strbuf value;
        struct strbuf var;

        int (*do_fgetc)(struct config_source *c);
        int (*do_ungetc)(int c, struct config_source *conf);
        long (*do_ftell)(struct config_source *c);
};

/*
 * These variables record the "current" config source, which
 * can be accessed by parsing callbacks.
 *
 * The "cf" variable will be non-NULL only when we are actually parsing a real
 * config source (file, blob, cmdline, etc).
 *
 * The "current_config_kvi" variable will be non-NULL only when we are feeding
 * cached config from a configset into a callback.
 *
 * They should generally never be non-NULL at the same time. If they are both
 * NULL, then we aren't parsing anything (and depending on the function looking
 * at the variables, it's either a bug for it to be called in the first place,
 * or it's a function which can be reused for non-config purposes, and should
 * fall back to some sane behavior).
 */
static struct config_source *cf;
static struct key_value_info *current_config_kvi;

/*
 * Similar to the variables above, this gives access to the "scope" of the
 * current value (repo, global, etc). For cached values, it can be found via
 * the current_config_kvi as above. During parsing, the current value can be
 * found in this variable. It's not part of "cf" because it transcends a single
 * file (i.e., a file included from .git/config is still in "repo" scope).
 */
static enum config_scope current_parsing_scope;

static int core_compression_seen;
static int pack_compression_seen;
static int zlib_compression_seen;

static int config_file_fgetc(struct config_source *conf)
{
        return getc_unlocked(conf->u.file);
}

static int config_file_ungetc(int c, struct config_source *conf)
{
        return ungetc(c, conf->u.file);
}

static long config_file_ftell(struct config_source *conf)
{
        return ftell(conf->u.file);
}


static int config_buf_fgetc(struct config_source *conf)
{
        if (conf->u.buf.pos < conf->u.buf.len)
                return conf->u.buf.buf[conf->u.buf.pos++];

        return EOF;
}

static int config_buf_ungetc(int c, struct config_source *conf)
{
        if (conf->u.buf.pos > 0) {
                conf->u.buf.pos--;
                if (conf->u.buf.buf[conf->u.buf.pos] != c)
                        BUG("config_buf can only ungetc the same character");
                return c;
        }

        return EOF;
}

static long config_buf_ftell(struct config_source *conf)
{
        return conf->u.buf.pos;
}

#define MAX_INCLUDE_DEPTH 10
static const char include_depth_advice[] = N_(
"exceeded maximum include depth (%d) while including\n"
"       %s\n"
"from\n"
"       %s\n"
"Do you have circular includes?");
static int handle_path_include(const char *path, struct config_include_data *inc)
{
        int ret = 0;
        struct strbuf buf = STRBUF_INIT;
        char *expanded;

        if (!path)
                return config_error_nonbool("include.path");

        expanded = expand_user_path(path, 0);
        if (!expanded)
                return error(_("could not expand include path '%s'"), path);
        path = expanded;

        /*
         * Use an absolute path as-is, but interpret relative paths
         * based on the including config file.
         */
        if (!is_absolute_path(path)) {
                char *slash;

                if (!cf || !cf->path)
                        return error(_("relative config includes must come from files"));

                slash = find_last_dir_sep(cf->path);
                if (slash)
                        strbuf_add(&buf, cf->path, slash - cf->path + 1);
                strbuf_addstr(&buf, path);
                path = buf.buf;
        }

        if (!access_or_die(path, R_OK, 0)) {
                if (++inc->depth > MAX_INCLUDE_DEPTH)
                        die(_(include_depth_advice), MAX_INCLUDE_DEPTH, path,
                            !cf ? "<unknown>" :
                            cf->name ? cf->name :
                            "the command line");
                ret = git_config_from_file(git_config_include, path, inc);
                inc->depth--;
        }
        strbuf_release(&buf);
        free(expanded);
        return ret;
}

static int prepare_include_condition_pattern(struct strbuf *pat)
{
        struct strbuf path = STRBUF_INIT;
        char *expanded;
        int prefix = 0;

        expanded = expand_user_path(pat->buf, 1);
        if (expanded) {
                strbuf_reset(pat);
                strbuf_addstr(pat, expanded);
                free(expanded);
        }

        if (pat->buf[0] == '.' && is_dir_sep(pat->buf[1])) {
                const char *slash;

                if (!cf || !cf->path)
                        return error(_("relative config include "
                                       "conditionals must come from files"));

                strbuf_realpath(&path, cf->path, 1);
                slash = find_last_dir_sep(path.buf);
                if (!slash)
                        BUG("how is this possible?");
                strbuf_splice(pat, 0, 1, path.buf, slash - path.buf);
                prefix = slash - path.buf + 1 /* slash */;
        } else if (!is_absolute_path(pat->buf))
                strbuf_insert(pat, 0, "**/", 3);

        if (pat->len && is_dir_sep(pat->buf[pat->len - 1]))
                strbuf_addstr(pat, "**");

        strbuf_release(&path);
        return prefix;
}

static int include_by_gitdir(const struct config_options *opts,
                             const char *cond, size_t cond_len, int icase)
{
        struct strbuf text = STRBUF_INIT;
        struct strbuf pattern = STRBUF_INIT;
        int ret = 0, prefix;
        const char *git_dir;
        int already_tried_absolute = 0;

        if (opts->git_dir)
                git_dir = opts->git_dir;
        else
                goto done;

        strbuf_realpath(&text, git_dir, 1);
        strbuf_add(&pattern, cond, cond_len);
        prefix = prepare_include_condition_pattern(&pattern);

again:
        if (prefix < 0)
                goto done;

        if (prefix > 0) {
                /*
                 * perform literal matching on the prefix part so that
                 * any wildcard character in it can't create side effects.
                 */
                if (text.len < prefix)
                        goto done;
                if (!icase && strncmp(pattern.buf, text.buf, prefix))
                        goto done;
                if (icase && strncasecmp(pattern.buf, text.buf, prefix))
                        goto done;
        }

        ret = !wildmatch(pattern.buf + prefix, text.buf + prefix,
                         icase ? WM_CASEFOLD : 0);

        if (!ret && !already_tried_absolute) {
                /*
                 * We've tried e.g. matching gitdir:~/work, but if
                 * ~/work is a symlink to /mnt/storage/work
                 * strbuf_realpath() will expand it, so the rule won't
                 * match. Let's match against a
                 * strbuf_add_absolute_path() version of the path,
                 * which'll do the right thing
                 */
                strbuf_reset(&text);
                strbuf_add_absolute_path(&text, git_dir);
                already_tried_absolute = 1;
                goto again;
        }
done:
        strbuf_release(&pattern);
        strbuf_release(&text);
        return ret;
}

static int include_condition_is_true(const struct config_options *opts,
                                     const char *cond, size_t cond_len)
{

        if (skip_prefix_mem(cond, cond_len, "gitdir:", &cond, &cond_len))
                return include_by_gitdir(opts, cond, cond_len, 0);
        else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
                return include_by_gitdir(opts, cond, cond_len, 1);

        /* unknown conditionals are always false */
        return 0;
}

int git_config_include(const char *var, const char *value, void *data)
{
        struct config_include_data *inc = data;
        const char *cond, *key;
        int cond_len;
        int ret;

        /*
         * Pass along all values, including "include" directives; this makes it
         * possible to query information on the includes themselves.
         */
        ret = inc->fn(var, value, inc->data);
        if (ret < 0)
                return ret;

        if (!strcmp(var, "include.path"))
                ret = handle_path_include(value, inc);

        if (!parse_config_key(var, "includeif", &cond, &cond_len, &key) &&
            (cond && include_condition_is_true(inc->opts, cond, cond_len)) &&
            !strcmp(key, "path"))
                ret = handle_path_include(value, inc);

        return ret;
}

void git_config_push_parameter(const char *text)
{
        struct strbuf env = STRBUF_INIT;
        const char *old = getenv(CONFIG_DATA_ENVIRONMENT);
        if (old && *old) {
                strbuf_addstr(&env, old);
                strbuf_addch(&env, ' ');
        }
        sq_quote_buf(&env, text);
        setenv(CONFIG_DATA_ENVIRONMENT, env.buf, 1);
        strbuf_release(&env);
}

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

/*
 * Auxiliary function to sanity-check and split the key into the section
 * identifier and variable name.
 *
 * Returns 0 on success, -1 when there is an invalid character in the key and
 * -2 if there is no section name in the key.
 *
 * store_key - pointer to char* which will hold a copy of the key with
 *             lowercase section and variable name
 * baselen - pointer to int which will hold the length of the
 *           section + subsection part, can be NULL
 */
static int git_config_parse_key_1(const char *key, char **store_key, int *baselen_, int quiet)
{
        int i, dot, baselen;
        const char *last_dot = strrchr(key, '.');

        /*
         * Since "key" actually contains the section name and the real
         * key name separated by a dot, we have to know where the dot is.
         */

        if (last_dot == NULL || last_dot == key) {
                if (!quiet)
                        error(_("key does not contain a section: %s"), key);
                return -CONFIG_NO_SECTION_OR_NAME;
        }

        if (!last_dot[1]) {
                if (!quiet)
                        error(_("key does not contain variable name: %s"), key);
                return -CONFIG_NO_SECTION_OR_NAME;
        }

        baselen = last_dot - key;
        if (baselen_)
                *baselen_ = baselen;

        /*
         * Validate the key and while at it, lower case it for matching.
         */
        if (store_key)
                *store_key = xmallocz(strlen(key));

        dot = 0;
        for (i = 0; key[i]; i++) {
                unsigned char c = key[i];
                if (c == '.')
                        dot = 1;
                /* Leave the extended basename untouched.. */
                if (!dot || i > baselen) {
                        if (!iskeychar(c) ||
                            (i == baselen + 1 && !isalpha(c))) {
                                if (!quiet)
                                        error(_("invalid key: %s"), key);
                                goto out_free_ret_1;
                        }
                        c = tolower(c);
                } else if (c == '\n') {
                        if (!quiet)
                                error(_("invalid key (newline): %s"), key);
                        goto out_free_ret_1;
                }
                if (store_key)
                        (*store_key)[i] = c;
        }

        return 0;

out_free_ret_1:
        if (store_key) {
                FREE_AND_NULL(*store_key);
        }
        return -CONFIG_INVALID_KEY;
}

int git_config_parse_key(const char *key, char **store_key, int *baselen)
{
        return git_config_parse_key_1(key, store_key, baselen, 0);
}

int git_config_key_is_valid(const char *key)
{
        return !git_config_parse_key_1(key, NULL, NULL, 1);
}

int git_config_parse_parameter(const char *text,
                               config_fn_t fn, void *data)
{
        const char *value;
        char *canonical_name;
        struct strbuf **pair;
        int ret;

        pair = strbuf_split_str(text, '=', 2);
        if (!pair[0])
                return error(_("bogus config parameter: %s"), text);

        if (pair[0]->len && pair[0]->buf[pair[0]->len - 1] == '=') {
                strbuf_setlen(pair[0], pair[0]->len - 1);
                value = pair[1] ? pair[1]->buf : "";
        } else {
                value = NULL;
        }

        strbuf_trim(pair[0]);
        if (!pair[0]->len) {
                strbuf_list_free(pair);
                return error(_("bogus config parameter: %s"), text);
        }

        if (git_config_parse_key(pair[0]->buf, &canonical_name, NULL)) {
                ret = -1;
        } else {
                ret = (fn(canonical_name, value, data) < 0) ? -1 : 0;
                free(canonical_name);
        }
        strbuf_list_free(pair);
        return ret;
}

int git_config_from_parameters(config_fn_t fn, void *data)
{
        const char *env = getenv(CONFIG_DATA_ENVIRONMENT);
        int ret = 0;
        char *envw;
        const char **argv = NULL;
        int nr = 0, alloc = 0;
        int i;
        struct config_source source;

        if (!env)
                return 0;

        memset(&source, 0, sizeof(source));
        source.prev = cf;
        source.origin_type = CONFIG_ORIGIN_CMDLINE;
        cf = &source;

        /* sq_dequote will write over it */
        envw = xstrdup(env);

        if (sq_dequote_to_argv(envw, &argv, &nr, &alloc) < 0) {
                ret = error(_("bogus format in %s"), CONFIG_DATA_ENVIRONMENT);
                goto out;
        }

        for (i = 0; i < nr; i++) {
                if (git_config_parse_parameter(argv[i], fn, data) < 0) {
                        ret = -1;
                        goto out;
                }
        }

out:
        free(argv);
        free(envw);
        cf = source.prev;
        return ret;
}

static int get_next_char(void)
{
        int c = cf->do_fgetc(cf);

        if (c == '\r') {
                /* DOS like systems */
                c = cf->do_fgetc(cf);
                if (c != '\n') {
                        if (c != EOF)
                                cf->do_ungetc(c, cf);
                        c = '\r';
                }
        }
        if (c == '\n')
                cf->linenr++;
        if (c == EOF) {
                cf->eof = 1;
                cf->linenr++;
                c = '\n';
        }
        return c;
}

static char *parse_value(void)
{
        int quote = 0, comment = 0, space = 0;

        strbuf_reset(&cf->value);
        for (;;) {
                int c = get_next_char();
                if (c == '\n') {
                        if (quote) {
                                cf->linenr--;
                                return NULL;
                        }
                        return cf->value.buf;
                }
                if (comment)
                        continue;
                if (isspace(c) && !quote) {
                        if (cf->value.len)
                                space++;
                        continue;
                }
                if (!quote) {
                        if (c == ';' || c == '#') {
                                comment = 1;
                                continue;
                        }
                }
                for (; space; space--)
                        strbuf_addch(&cf->value, ' ');
                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;
                        }
                        strbuf_addch(&cf->value, c);
                        continue;
                }
                if (c == '"') {
                        quote = 1-quote;
                        continue;
                }
                strbuf_addch(&cf->value, c);
        }
}

static int get_value(config_fn_t fn, void *data, struct strbuf *name)
{
        int c;
        char *value;
        int ret;

        /* Get the full name */
        for (;;) {
                c = get_next_char();
                if (cf->eof)
                        break;
                if (!iskeychar(c))
                        break;
                strbuf_addch(name, tolower(c));
        }

        while (c == ' ' || c == '\t')
                c = get_next_char();

        value = NULL;
        if (c != '\n') {
                if (c != '=')
                        return -1;
                value = parse_value();
                if (!value)
                        return -1;
        }
        /*
         * We already consumed the \n, but we need linenr to point to
         * the line we just parsed during the call to fn to get
         * accurate line number in error messages.
         */
        cf->linenr--;
        ret = fn(name->buf, value, data);
        if (ret >= 0)
                cf->linenr++;
        return ret;
}

static int get_extended_base_var(struct strbuf *name, int c)
{
        do {
                if (c == '\n')
                        goto error_incomplete_line;
                c = get_next_char();
        } while (isspace(c));

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

        for (;;) {
                int c = get_next_char();
                if (c == '\n')
                        goto error_incomplete_line;
                if (c == '"')
                        break;
                if (c == '\\') {
                        c = get_next_char();
                        if (c == '\n')
                                goto error_incomplete_line;
                }
                strbuf_addch(name, c);
        }

        /* Final ']' */
        if (get_next_char() != ']')
                return -1;
        return 0;
error_incomplete_line:
        cf->linenr--;
        return -1;
}

static int get_base_var(struct strbuf *name)
{
        for (;;) {
                int c = get_next_char();
                if (cf->eof)
                        return -1;
                if (c == ']')
                        return 0;
                if (isspace(c))
                        return get_extended_base_var(name, c);
                if (!iskeychar(c) && c != '.')
                        return -1;
                strbuf_addch(name, tolower(c));
        }
}

struct parse_event_data {
        enum config_event_t previous_type;
        size_t previous_offset;
        const struct config_options *opts;
};

static int do_event(enum config_event_t type, struct parse_event_data *data)
{
        size_t offset;

        if (!data->opts || !data->opts->event_fn)
                return 0;

        if (type == CONFIG_EVENT_WHITESPACE &&
            data->previous_type == type)
                return 0;

        offset = cf->do_ftell(cf);
        /*
         * At EOF, the parser always "inserts" an extra '\n', therefore
         * the end offset of the event is the current file position, otherwise
         * we will already have advanced to the next event.
         */
        if (type != CONFIG_EVENT_EOF)
                offset--;

        if (data->previous_type != CONFIG_EVENT_EOF &&
            data->opts->event_fn(data->previous_type, data->previous_offset,
                                 offset, data->opts->event_fn_data) < 0)
                return -1;

        data->previous_type = type;
        data->previous_offset = offset;

        return 0;
}

static int git_parse_source(config_fn_t fn, void *data,
                            const struct config_options *opts)
{
        int comment = 0;
        int baselen = 0;
        struct strbuf *var = &cf->var;
        int error_return = 0;
        char *error_msg = NULL;

        /* U+FEFF Byte Order Mark in UTF8 */
        const char *bomptr = utf8_bom;

        /* For the parser event callback */
        struct parse_event_data event_data = {
                CONFIG_EVENT_EOF, 0, opts
        };

        for (;;) {
                int c;

                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 (c == (*bomptr & 0377)) {
                                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 (cf->eof) {
                                if (do_event(CONFIG_EVENT_EOF, &event_data) < 0)
                                        return -1;
                                return 0;
                        }
                        if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
                                return -1;
                        comment = 0;
                        continue;
                }
                if (comment)
                        continue;
                if (isspace(c)) {
                        if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
                                        return -1;
                        continue;
                }
                if (c == '#' || c == ';') {
                        if (do_event(CONFIG_EVENT_COMMENT, &event_data) < 0)
                                        return -1;
                        comment = 1;
                        continue;
                }
                if (c == '[') {
                        if (do_event(CONFIG_EVENT_SECTION, &event_data) < 0)
                                        return -1;

                        /* Reset prior to determining a new stem */
                        strbuf_reset(var);
                        if (get_base_var(var) < 0 || var->len < 1)
                                break;
                        strbuf_addch(var, '.');
                        baselen = var->len;
                        continue;
                }
                if (!isalpha(c))
                        break;

                if (do_event(CONFIG_EVENT_ENTRY, &event_data) < 0)
                        return -1;

                /*
                 * Truncate the var name back to the section header
                 * stem prior to grabbing the suffix part of the name
                 * and the value.
                 */
                strbuf_setlen(var, baselen);
                strbuf_addch(var, tolower(c));
                if (get_value(fn, data, var) < 0)
                        break;
        }

        if (do_event(CONFIG_EVENT_ERROR, &event_data) < 0)
                return -1;

        switch (cf->origin_type) {
        case CONFIG_ORIGIN_BLOB:
                error_msg = xstrfmt(_("bad config line %d in blob %s"),
                                      cf->linenr, cf->name);
                break;
        case CONFIG_ORIGIN_FILE:
                error_msg = xstrfmt(_("bad config line %d in file %s"),
                                      cf->linenr, cf->name);
                break;
        case CONFIG_ORIGIN_STDIN:
                error_msg = xstrfmt(_("bad config line %d in standard input"),
                                      cf->linenr);
                break;
        case CONFIG_ORIGIN_SUBMODULE_BLOB:
                error_msg = xstrfmt(_("bad config line %d in submodule-blob %s"),
                                       cf->linenr, cf->name);
                break;
        case CONFIG_ORIGIN_CMDLINE:
                error_msg = xstrfmt(_("bad config line %d in command line %s"),
                                       cf->linenr, cf->name);
                break;
        default:
                error_msg = xstrfmt(_("bad config line %d in %s"),
                                      cf->linenr, cf->name);
        }

        switch (opts && opts->error_action ?
                opts->error_action :
                cf->default_error_action) {
        case CONFIG_ERROR_DIE:
                die("%s", error_msg);
                break;
        case CONFIG_ERROR_ERROR:
                error_return = error("%s", error_msg);
                break;
        case CONFIG_ERROR_SILENT:
                error_return = -1;
                break;
        case CONFIG_ERROR_UNSET:
                BUG("config error action unset");
        }

        free(error_msg);
        return error_return;
}

static int parse_unit_factor(const char *end, uintmax_t *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 git_parse_signed(const char *value, intmax_t *ret, intmax_t max)
{
        if (value && *value) {
                char *end;
                intmax_t val;
                uintmax_t uval;
                uintmax_t factor = 1;

                errno = 0;
                val = strtoimax(value, &end, 0);
                if (errno == ERANGE)
                        return 0;
                if (!parse_unit_factor(end, &factor)) {
                        errno = EINVAL;
                        return 0;
                }
                uval = labs(val);
                uval *= factor;
                if (uval > max || labs(val) > uval) {
                        errno = ERANGE;
                        return 0;
                }
                val *= factor;
                *ret = val;
                return 1;
        }
        errno = EINVAL;
        return 0;
}

static int git_parse_unsigned(const char *value, uintmax_t *ret, uintmax_t max)
{
        if (value && *value) {
                char *end;
                uintmax_t val;
                uintmax_t oldval;

                errno = 0;
                val = strtoumax(value, &end, 0);
                if (errno == ERANGE)
                        return 0;
                oldval = val;
                if (!parse_unit_factor(end, &val)) {
                        errno = EINVAL;
                        return 0;
                }
                if (val > max || oldval > val) {
                        errno = ERANGE;
                        return 0;
                }
                *ret = val;
                return 1;
        }
        errno = EINVAL;
        return 0;
}

static int git_parse_int(const char *value, int *ret)
{
        intmax_t tmp;
        if (!git_parse_signed(value, &tmp, maximum_signed_value_of_type(int)))
                return 0;
        *ret = tmp;
        return 1;
}

static int git_parse_int64(const char *value, int64_t *ret)
{
        intmax_t tmp;
        if (!git_parse_signed(value, &tmp, maximum_signed_value_of_type(int64_t)))
                return 0;
        *ret = tmp;
        return 1;
}

int git_parse_ulong(const char *value, unsigned long *ret)
{
        uintmax_t tmp;
        if (!git_parse_unsigned(value, &tmp, maximum_unsigned_value_of_type(long)))
                return 0;
        *ret = tmp;
        return 1;
}

int git_parse_ssize_t(const char *value, ssize_t *ret)
{
        intmax_t tmp;
        if (!git_parse_signed(value, &tmp, maximum_signed_value_of_type(ssize_t)))
                return 0;
        *ret = tmp;
        return 1;
}

NORETURN
static void die_bad_number(const char *name, const char *value)
{
        const char * error_type = (errno == ERANGE)? _("out of range"):_("invalid unit");

        if (!value)
                value = "";

        if (!(cf && cf->name))
                die(_("bad numeric config value '%s' for '%s': %s"),
                    value, name, error_type);

        switch (cf->origin_type) {
        case CONFIG_ORIGIN_BLOB:
                die(_("bad numeric config value '%s' for '%s' in blob %s: %s"),
                    value, name, cf->name, error_type);
        case CONFIG_ORIGIN_FILE:
                die(_("bad numeric config value '%s' for '%s' in file %s: %s"),
                    value, name, cf->name, error_type);
        case CONFIG_ORIGIN_STDIN:
                die(_("bad numeric config value '%s' for '%s' in standard input: %s"),
                    value, name, error_type);
        case CONFIG_ORIGIN_SUBMODULE_BLOB:
                die(_("bad numeric config value '%s' for '%s' in submodule-blob %s: %s"),
                    value, name, cf->name, error_type);
        case CONFIG_ORIGIN_CMDLINE:
                die(_("bad numeric config value '%s' for '%s' in command line %s: %s"),
                    value, name, cf->name, error_type);
        default:
                die(_("bad numeric config value '%s' for '%s' in %s: %s"),
                    value, name, cf->name, error_type);
        }
}

int git_config_int(const char *name, const char *value)
{
        int ret;
        if (!git_parse_int(value, &ret))
                die_bad_number(name, value);
        return ret;
}

int64_t git_config_int64(const char *name, const char *value)
{
        int64_t ret;
        if (!git_parse_int64(value, &ret))
                die_bad_number(name, value);
        return ret;
}

unsigned long git_config_ulong(const char *name, const char *value)
{
        unsigned long ret;
        if (!git_parse_ulong(value, &ret))
                die_bad_number(name, value);
        return ret;
}

ssize_t git_config_ssize_t(const char *name, const char *value)
{
        ssize_t ret;
        if (!git_parse_ssize_t(value, &ret))
                die_bad_number(name, value);
        return ret;
}

static int git_parse_maybe_bool_text(const char *value)
{
        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;
        return -1;
}

int git_parse_maybe_bool(const char *value)
{
        int v = git_parse_maybe_bool_text(value);
        if (0 <= v)
                return v;
        if (git_parse_int(value, &v))
                return !!v;
        return -1;
}

int git_config_bool_or_int(const char *name, const char *value, int *is_bool)
{
        int v = git_parse_maybe_bool_text(value);
        if (0 <= v) {
                *is_bool = 1;
                return v;
        }
        *is_bool = 0;
        return git_config_int(name, value);
}

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

int git_config_string(const char **dest, const char *var, const char *value)
{
        if (!value)
                return config_error_nonbool(var);
        *dest = xstrdup(value);
        return 0;
}

int git_config_pathname(const char **dest, const char *var, const char *value)
{
        if (!value)
                return config_error_nonbool(var);
        *dest = expand_user_path(value, 0);
        if (!*dest)
                die(_("failed to expand user dir in: '%s'"), value);
        return 0;
}

int git_config_expiry_date(timestamp_t *timestamp, const char *var, const char *value)
{
        if (!value)
                return config_error_nonbool(var);
        if (parse_expiry_date(value, timestamp))
                return error(_("'%s' for '%s' is not a valid timestamp"),
                             value, var);
        return 0;
}

int git_config_color(char *dest, const char *var, const char *value)
{
        if (!value)
                return config_error_nonbool(var);
        if (color_parse(value, dest) < 0)
                return -1;
        return 0;
}

static int git_default_core_config(const char *var, const char *value)
{
        /* This needs a better name */
        if (!strcmp(var, "core.filemode")) {
                trust_executable_bit = git_config_bool(var, value);
                return 0;
        }
        if (!strcmp(var, "core.trustctime")) {
                trust_ctime = git_config_bool(var, value);
                return 0;
        }
        if (!strcmp(var, "core.checkstat")) {
                if (!strcasecmp(value, "default"))
                        check_stat = 1;
                else if (!strcasecmp(value, "minimal"))
                        check_stat = 0;
        }

        if (!strcmp(var, "core.quotepath")) {
                quote_path_fully = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.symlinks")) {
                has_symlinks = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.ignorecase")) {
                ignore_case = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.attributesfile"))
                return git_config_pathname(&git_attributes_file, var, value);

        if (!strcmp(var, "core.hookspath"))
                return git_config_pathname(&git_hooks_path, var, value);

        if (!strcmp(var, "core.bare")) {
                is_bare_repository_cfg = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.ignorestat")) {
                assume_unchanged = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.prefersymlinkrefs")) {
                prefer_symlink_refs = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.logallrefupdates")) {
                if (value && !strcasecmp(value, "always"))
                        log_all_ref_updates = LOG_REFS_ALWAYS;
                else if (git_config_bool(var, value))
                        log_all_ref_updates = LOG_REFS_NORMAL;
                else
                        log_all_ref_updates = LOG_REFS_NONE;
                return 0;
        }

        if (!strcmp(var, "core.warnambiguousrefs")) {
                warn_ambiguous_refs = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.abbrev")) {
                if (!value)
                        return config_error_nonbool(var);
                if (!strcasecmp(value, "auto"))
                        default_abbrev = -1;
                else {
                        int abbrev = git_config_int(var, value);
                        if (abbrev < minimum_abbrev || abbrev > 40)
                                return error(_("abbrev length out of range: %d"), abbrev);
                        default_abbrev = abbrev;
                }
                return 0;
        }

        if (!strcmp(var, "core.disambiguate"))
                return set_disambiguate_hint_config(var, value);

        if (!strcmp(var, "core.loosecompression")) {
                int level = git_config_int(var, value);
                if (level == -1)
                        level = Z_DEFAULT_COMPRESSION;
                else if (level < 0 || level > Z_BEST_COMPRESSION)
                        die(_("bad zlib compression level %d"), level);
                zlib_compression_level = level;
                zlib_compression_seen = 1;
                return 0;
        }

        if (!strcmp(var, "core.compression")) {
                int level = git_config_int(var, value);
                if (level == -1)
                        level = Z_DEFAULT_COMPRESSION;
                else if (level < 0 || level > Z_BEST_COMPRESSION)
                        die(_("bad zlib compression level %d"), level);
                core_compression_level = level;
                core_compression_seen = 1;
                if (!zlib_compression_seen)
                        zlib_compression_level = level;
                if (!pack_compression_seen)
                        pack_compression_level = level;
                return 0;
        }

        if (!strcmp(var, "core.packedgitwindowsize")) {
                int pgsz_x2 = getpagesize() * 2;
                packed_git_window_size = git_config_ulong(var, value);

                /* This value must be multiple of (pagesize * 2) */
                packed_git_window_size /= pgsz_x2;
                if (packed_git_window_size < 1)
                        packed_git_window_size = 1;
                packed_git_window_size *= pgsz_x2;
                return 0;
        }

        if (!strcmp(var, "core.bigfilethreshold")) {
                big_file_threshold = git_config_ulong(var, value);
                return 0;
        }

        if (!strcmp(var, "core.packedgitlimit")) {
                packed_git_limit = git_config_ulong(var, value);
                return 0;
        }

        if (!strcmp(var, "core.deltabasecachelimit")) {
                delta_base_cache_limit = git_config_ulong(var, value);
                return 0;
        }

        if (!strcmp(var, "core.autocrlf")) {
                if (value && !strcasecmp(value, "input")) {
                        auto_crlf = AUTO_CRLF_INPUT;
                        return 0;
                }
                auto_crlf = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.safecrlf")) {
                int eol_rndtrp_die;
                if (value && !strcasecmp(value, "warn")) {
                        global_conv_flags_eol = CONV_EOL_RNDTRP_WARN;
                        return 0;
                }
                eol_rndtrp_die = git_config_bool(var, value);
                global_conv_flags_eol = eol_rndtrp_die ?
                        CONV_EOL_RNDTRP_DIE : 0;
                return 0;
        }

        if (!strcmp(var, "core.eol")) {
                if (value && !strcasecmp(value, "lf"))
                        core_eol = EOL_LF;
                else if (value && !strcasecmp(value, "crlf"))
                        core_eol = EOL_CRLF;
                else if (value && !strcasecmp(value, "native"))
                        core_eol = EOL_NATIVE;
                else
                        core_eol = EOL_UNSET;
                return 0;
        }

        if (!strcmp(var, "core.checkroundtripencoding")) {
                check_roundtrip_encoding = xstrdup(value);
                return 0;
        }

        if (!strcmp(var, "core.notesref")) {
                notes_ref_name = xstrdup(value);
                return 0;
        }

        if (!strcmp(var, "core.editor"))
                return git_config_string(&editor_program, var, value);

        if (!strcmp(var, "core.commentchar")) {
                if (!value)
                        return config_error_nonbool(var);
                else if (!strcasecmp(value, "auto"))
                        auto_comment_line_char = 1;
                else if (value[0] && !value[1]) {
                        comment_line_char = value[0];
                        auto_comment_line_char = 0;
                } else
                        return error(_("core.commentChar should only be one character"));
                return 0;
        }

        if (!strcmp(var, "core.askpass"))
                return git_config_string(&askpass_program, var, value);

        if (!strcmp(var, "core.excludesfile"))
                return git_config_pathname(&excludes_file, var, value);

        if (!strcmp(var, "core.whitespace")) {
                if (!value)
                        return config_error_nonbool(var);
                whitespace_rule_cfg = parse_whitespace_rule(value);
                return 0;
        }

        if (!strcmp(var, "core.fsyncobjectfiles")) {
                fsync_object_files = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.preloadindex")) {
                core_preload_index = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.createobject")) {
                if (!strcmp(value, "rename"))
                        object_creation_mode = OBJECT_CREATION_USES_RENAMES;
                else if (!strcmp(value, "link"))
                        object_creation_mode = OBJECT_CREATION_USES_HARDLINKS;
                else
                        die(_("invalid mode for object creation: %s"), value);
                return 0;
        }

        if (!strcmp(var, "core.sparsecheckout")) {
                core_apply_sparse_checkout = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.precomposeunicode")) {
                precomposed_unicode = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.protecthfs")) {
                protect_hfs = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.protectntfs")) {
                protect_ntfs = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.hidedotfiles")) {
                if (value && !strcasecmp(value, "dotgitonly"))
                        hide_dotfiles = HIDE_DOTFILES_DOTGITONLY;
                else
                        hide_dotfiles = git_config_bool(var, value);
                return 0;
        }

        if (!strcmp(var, "core.partialclonefilter")) {
                return git_config_string(&core_partial_clone_filter_default,
                                         var, value);
        }

        if (!strcmp(var, "core.usereplacerefs")) {
                read_replace_refs = git_config_bool(var, value);
                return 0;
        }

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

static int git_default_i18n_config(const char *var, const char *value)
{
        if (!strcmp(var, "i18n.commitencoding"))
                return git_config_string(&git_commit_encoding, var, value);

        if (!strcmp(var, "i18n.logoutputencoding"))
                return git_config_string(&git_log_output_encoding, var, value);

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

static int git_default_branch_config(const char *var, const char *value)
{
        if (!strcmp(var, "branch.autosetupmerge")) {
                if (value && !strcasecmp(value, "always")) {
                        git_branch_track = BRANCH_TRACK_ALWAYS;
                        return 0;
                }
                git_branch_track = git_config_bool(var, value);
                return 0;
        }
        if (!strcmp(var, "branch.autosetuprebase")) {
                if (!value)
                        return config_error_nonbool(var);
                else if (!strcmp(value, "never"))
                        autorebase = AUTOREBASE_NEVER;
                else if (!strcmp(value, "local"))
                        autorebase = AUTOREBASE_LOCAL;
                else if (!strcmp(value, "remote"))
                        autorebase = AUTOREBASE_REMOTE;
                else if (!strcmp(value, "always"))
                        autorebase = AUTOREBASE_ALWAYS;
                else
                        return error(_("malformed value for %s"), var);
                return 0;
        }

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

static int git_default_push_config(const char *var, const char *value)
{
        if (!strcmp(var, "push.default")) {
                if (!value)
                        return config_error_nonbool(var);
                else if (!strcmp(value, "nothing"))
                        push_default = PUSH_DEFAULT_NOTHING;
                else if (!strcmp(value, "matching"))
                        push_default = PUSH_DEFAULT_MATCHING;
                else if (!strcmp(value, "simple"))
                        push_default = PUSH_DEFAULT_SIMPLE;
                else if (!strcmp(value, "upstream"))
                        push_default = PUSH_DEFAULT_UPSTREAM;
                else if (!strcmp(value, "tracking")) /* deprecated */
                        push_default = PUSH_DEFAULT_UPSTREAM;
                else if (!strcmp(value, "current"))
                        push_default = PUSH_DEFAULT_CURRENT;
                else {
                        error(_("malformed value for %s: %s"), var, value);
                        return error(_("must be one of nothing, matching, simple, "
                                       "upstream or current"));
                }
                return 0;
        }

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

static int git_default_mailmap_config(const char *var, const char *value)
{
        if (!strcmp(var, "mailmap.file"))
                return git_config_pathname(&git_mailmap_file, var, value);
        if (!strcmp(var, "mailmap.blob"))
                return git_config_string(&git_mailmap_blob, var, value);

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

int git_default_config(const char *var, const char *value, void *dummy)
{
        if (starts_with(var, "core."))
                return git_default_core_config(var, value);

        if (starts_with(var, "user."))
                return git_ident_config(var, value, dummy);

        if (starts_with(var, "i18n."))
                return git_default_i18n_config(var, value);

        if (starts_with(var, "branch."))
                return git_default_branch_config(var, value);

        if (starts_with(var, "push."))
                return git_default_push_config(var, value);

        if (starts_with(var, "mailmap."))
                return git_default_mailmap_config(var, value);

        if (starts_with(var, "advice.") || starts_with(var, "color.advice"))
                return git_default_advice_config(var, value);

        if (!strcmp(var, "pager.color") || !strcmp(var, "color.pager")) {
                pager_use_color = git_config_bool(var,value);
                return 0;
        }

        if (!strcmp(var, "pack.packsizelimit")) {
                pack_size_limit_cfg = git_config_ulong(var, value);
                return 0;
        }

        if (!strcmp(var, "pack.compression")) {
                int level = git_config_int(var, value);
                if (level == -1)
                        level = Z_DEFAULT_COMPRESSION;
                else if (level < 0 || level > Z_BEST_COMPRESSION)
                        die(_("bad pack compression level %d"), level);
                pack_compression_level = level;
                pack_compression_seen = 1;
                return 0;
        }

        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
}

/*
 * All source specific fields in the union, die_on_error, name and the callbacks
 * fgetc, ungetc, ftell of top need to be initialized before calling
 * this function.
 */
static int do_config_from(struct config_source *top, config_fn_t fn, void *data,
                          const struct config_options *opts)
{
        int ret;

        /* push config-file parsing state stack */
        top->prev = cf;
        top->linenr = 1;
        top->eof = 0;
        strbuf_init(&top->value, 1024);
        strbuf_init(&top->var, 1024);
        cf = top;

        ret = git_parse_source(fn, data, opts);

        /* pop config-file parsing state stack */
        strbuf_release(&top->value);
        strbuf_release(&top->var);
        cf = top->prev;

        return ret;
}

static int do_config_from_file(config_fn_t fn,
                const enum config_origin_type origin_type,
                const char *name, const char *path, FILE *f,
                void *data, const struct config_options *opts)
{
        struct config_source top;
        int ret;

        top.u.file = f;
        top.origin_type = origin_type;
        top.name = name;
        top.path = path;
        top.default_error_action = CONFIG_ERROR_DIE;
        top.do_fgetc = config_file_fgetc;
        top.do_ungetc = config_file_ungetc;
        top.do_ftell = config_file_ftell;

        flockfile(f);
        ret = do_config_from(&top, fn, data, opts);
        funlockfile(f);
        return ret;
}

static int git_config_from_stdin(config_fn_t fn, void *data)
{
        return do_config_from_file(fn, CONFIG_ORIGIN_STDIN, "", NULL, stdin,
                                   data, NULL);
}

int git_config_from_file_with_options(config_fn_t fn, const char *filename,
                                      void *data,
                                      const struct config_options *opts)
{
        int ret = -1;
        FILE *f;

        f = fopen_or_warn(filename, "r");
        if (f) {
                ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename,
                                          filename, f, data, opts);
                fclose(f);
        }
        return ret;
}

int git_config_from_file(config_fn_t fn, const char *filename, void *data)
{
        return git_config_from_file_with_options(fn, filename, data, NULL);
}

int git_config_from_mem(config_fn_t fn,
                        const enum config_origin_type origin_type,
                        const char *name, const char *buf, size_t len,
                        void *data, const struct config_options *opts)
{
        struct config_source top;

        top.u.buf.buf = buf;
        top.u.buf.len = len;
        top.u.buf.pos = 0;
        top.origin_type = origin_type;
        top.name = name;
        top.path = NULL;
        top.default_error_action = CONFIG_ERROR_ERROR;
        top.do_fgetc = config_buf_fgetc;
        top.do_ungetc = config_buf_ungetc;
        top.do_ftell = config_buf_ftell;

        return do_config_from(&top, fn, data, opts);
}

int git_config_from_blob_oid(config_fn_t fn,
                              const char *name,
                              const struct object_id *oid,
                              void *data)
{
        enum object_type type;
        char *buf;
        unsigned long size;
        int ret;

        buf = read_object_file(oid, &type, &size);
        if (!buf)
                return error(_("unable to load config blob object '%s'"), name);
        if (type != OBJ_BLOB) {
                free(buf);
                return error(_("reference '%s' does not point to a blob"), name);
        }

        ret = git_config_from_mem(fn, CONFIG_ORIGIN_BLOB, name, buf, size,
                                  data, NULL);
        free(buf);

        return ret;
}

static int git_config_from_blob_ref(config_fn_t fn,
                                    const char *name,
                                    void *data)
{
        struct object_id oid;

        if (get_oid(name, &oid) < 0)
                return error(_("unable to resolve config blob '%s'"), name);
        return git_config_from_blob_oid(fn, name, &oid, data);
}

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

/*
 * Parse environment variable 'k' as a boolean (in various
 * possible spellings); if missing, use the default value 'def'.
 */
int git_env_bool(const char *k, int def)
{
        const char *v = getenv(k);
        return v ? git_config_bool(k, v) : def;
}

/*
 * Parse environment variable 'k' as ulong with possibly a unit
 * suffix; if missing, use the default value 'val'.
 */
unsigned long git_env_ulong(const char *k, unsigned long val)
{
        const char *v = getenv(k);
        if (v && !git_parse_ulong(v, &val))
                die(_("failed to parse %s"), k);
        return val;
}

int git_config_system(void)
{
        return !git_env_bool("GIT_CONFIG_NOSYSTEM", 0);
}

static int do_git_config_sequence(const struct config_options *opts,
                                  config_fn_t fn, void *data)
{
        int ret = 0;
        char *xdg_config = xdg_config_home("config");
        char *user_config = expand_user_path("~/.gitconfig", 0);
        char *repo_config;

        if (opts->commondir)
                repo_config = mkpathdup("%s/config", opts->commondir);
        else
                repo_config = NULL;

        current_parsing_scope = CONFIG_SCOPE_SYSTEM;
        if (git_config_system() && !access_or_die(git_etc_gitconfig(), R_OK, 0))
                ret += git_config_from_file(fn, git_etc_gitconfig(),
                                            data);

        current_parsing_scope = CONFIG_SCOPE_GLOBAL;
        if (xdg_config && !access_or_die(xdg_config, R_OK, ACCESS_EACCES_OK))
                ret += git_config_from_file(fn, xdg_config, data);

        if (user_config && !access_or_die(user_config, R_OK, ACCESS_EACCES_OK))
                ret += git_config_from_file(fn, user_config, data);

        current_parsing_scope = CONFIG_SCOPE_REPO;
        if (repo_config && !access_or_die(repo_config, R_OK, 0))
                ret += git_config_from_file(fn, repo_config, data);

        current_parsing_scope = CONFIG_SCOPE_CMDLINE;
        if (git_config_from_parameters(fn, data) < 0)
                die(_("unable to parse command-line config"));

        current_parsing_scope = CONFIG_SCOPE_UNKNOWN;
        free(xdg_config);
        free(user_config);
        free(repo_config);
        return ret;
}

int config_with_options(config_fn_t fn, void *data,
                        struct git_config_source *config_source,
                        const struct config_options *opts)
{
        struct config_include_data inc = CONFIG_INCLUDE_INIT;

        if (opts->respect_includes) {
                inc.fn = fn;
                inc.data = data;
                inc.opts = opts;
                fn = git_config_include;
                data = &inc;
        }

        /*
         * If we have a specific filename, use it. Otherwise, follow the
         * regular lookup sequence.
         */
        if (config_source && config_source->use_stdin)
                return git_config_from_stdin(fn, data);
        else if (config_source && config_source->file)
                return git_config_from_file(fn, config_source->file, data);
        else if (config_source && config_source->blob)
                return git_config_from_blob_ref(fn, config_source->blob, data);

        return do_git_config_sequence(opts, fn, data);
}

static void configset_iter(struct config_set *cs, config_fn_t fn, void *data)
{
        int i, value_index;
        struct string_list *values;
        struct config_set_element *entry;
        struct configset_list *list = &cs->list;

        for (i = 0; i < list->nr; i++) {
                entry = list->items[i].e;
                value_index = list->items[i].value_index;
                values = &entry->value_list;

                current_config_kvi = values->items[value_index].util;

                if (fn(entry->key, values->items[value_index].string, data) < 0)
                        git_die_config_linenr(entry->key,
                                              current_config_kvi->filename,
                                              current_config_kvi->linenr);

                current_config_kvi = NULL;
        }
}

void read_early_config(config_fn_t cb, void *data)
{
        struct config_options opts = {0};
        struct strbuf commondir = STRBUF_INIT;
        struct strbuf gitdir = STRBUF_INIT;

        opts.respect_includes = 1;

        if (have_git_dir()) {
                opts.commondir = get_git_common_dir();
                opts.git_dir = get_git_dir();
        /*
         * When setup_git_directory() was not yet asked to discover the
         * GIT_DIR, we ask discover_git_directory() to figure out whether there
         * is any repository config we should use (but unlike
         * setup_git_directory_gently(), no global state is changed, most
         * notably, the current working directory is still the same after the
         * call).
         */
        } else if (!discover_git_directory(&commondir, &gitdir)) {
                opts.commondir = commondir.buf;
                opts.git_dir = gitdir.buf;
        }

        config_with_options(cb, data, NULL, &opts);

        strbuf_release(&commondir);
        strbuf_release(&gitdir);
}

static struct config_set_element *configset_find_element(struct config_set *cs, const char *key)
{
        struct config_set_element k;
        struct config_set_element *found_entry;
        char *normalized_key;
        /*
         * `key` may come from the user, so normalize it before using it
         * for querying entries from the hashmap.
         */
        if (git_config_parse_key(key, &normalized_key, NULL))
                return NULL;

        hashmap_entry_init(&k, strhash(normalized_key));
        k.key = normalized_key;
        found_entry = hashmap_get(&cs->config_hash, &k, NULL);
        free(normalized_key);
        return found_entry;
}

static int configset_add_value(struct config_set *cs, const char *key, const char *value)
{
        struct config_set_element *e;
        struct string_list_item *si;
        struct configset_list_item *l_item;
        struct key_value_info *kv_info = xmalloc(sizeof(*kv_info));

        e = configset_find_element(cs, key);
        /*
         * Since the keys are being fed by git_config*() callback mechanism, they
         * are already normalized. So simply add them without any further munging.
         */
        if (!e) {
                e = xmalloc(sizeof(*e));
                hashmap_entry_init(e, strhash(key));
                e->key = xstrdup(key);
                string_list_init(&e->value_list, 1);
                hashmap_add(&cs->config_hash, e);
        }
        si = string_list_append_nodup(&e->value_list, xstrdup_or_null(value));

        ALLOC_GROW(cs->list.items, cs->list.nr + 1, cs->list.alloc);
        l_item = &cs->list.items[cs->list.nr++];
        l_item->e = e;
        l_item->value_index = e->value_list.nr - 1;

        if (!cf)
                BUG("configset_add_value has no source");
        if (cf->name) {
                kv_info->filename = strintern(cf->name);
                kv_info->linenr = cf->linenr;
                kv_info->origin_type = cf->origin_type;
        } else {
                /* for values read from `git_config_from_parameters()` */
                kv_info->filename = NULL;
                kv_info->linenr = -1;
                kv_info->origin_type = CONFIG_ORIGIN_CMDLINE;
        }
        kv_info->scope = current_parsing_scope;
        si->util = kv_info;

        return 0;
}

static int config_set_element_cmp(const void *unused_cmp_data,
                                  const void *entry,
                                  const void *entry_or_key,
                                  const void *unused_keydata)
{
        const struct config_set_element *e1 = entry;
        const struct config_set_element *e2 = entry_or_key;

        return strcmp(e1->key, e2->key);
}

void git_configset_init(struct config_set *cs)
{
        hashmap_init(&cs->config_hash, config_set_element_cmp, NULL, 0);
        cs->hash_initialized = 1;
        cs->list.nr = 0;
        cs->list.alloc = 0;
        cs->list.items = NULL;
}

void git_configset_clear(struct config_set *cs)
{
        struct config_set_element *entry;
        struct hashmap_iter iter;
        if (!cs->hash_initialized)
                return;

        hashmap_iter_init(&cs->config_hash, &iter);
        while ((entry = hashmap_iter_next(&iter))) {
                free(entry->key);
                string_list_clear(&entry->value_list, 1);
        }
        hashmap_free(&cs->config_hash, 1);
        cs->hash_initialized = 0;
        free(cs->list.items);
        cs->list.nr = 0;
        cs->list.alloc = 0;
        cs->list.items = NULL;
}

static int config_set_callback(const char *key, const char *value, void *cb)
{
        struct config_set *cs = cb;
        configset_add_value(cs, key, value);
        return 0;
}

int git_configset_add_file(struct config_set *cs, const char *filename)
{
        return git_config_from_file(config_set_callback, filename, cs);
}

int git_configset_get_value(struct config_set *cs, const char *key, const char **value)
{
        const struct string_list *values = NULL;
        /*
         * Follows "last one wins" semantic, i.e., if there are multiple matches for the
         * queried key in the files of the configset, the value returned will be the last
         * value in the value list for that key.
         */
        values = git_configset_get_value_multi(cs, key);

        if (!values)
                return 1;
        assert(values->nr > 0);
        *value = values->items[values->nr - 1].string;
        return 0;
}

const struct string_list *git_configset_get_value_multi(struct config_set *cs, const char *key)
{
        struct config_set_element *e = configset_find_element(cs, key);
        return e ? &e->value_list : NULL;
}

int git_configset_get_string_const(struct config_set *cs, const char *key, const char **dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value))
                return git_config_string(dest, key, value);
        else
                return 1;
}

int git_configset_get_string(struct config_set *cs, const char *key, char **dest)
{
        return git_configset_get_string_const(cs, key, (const char **)dest);
}

int git_configset_get_int(struct config_set *cs, const char *key, int *dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value)) {
                *dest = git_config_int(key, value);
                return 0;
        } else
                return 1;
}

int git_configset_get_ulong(struct config_set *cs, const char *key, unsigned long *dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value)) {
                *dest = git_config_ulong(key, value);
                return 0;
        } else
                return 1;
}

int git_configset_get_bool(struct config_set *cs, const char *key, int *dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value)) {
                *dest = git_config_bool(key, value);
                return 0;
        } else
                return 1;
}

int git_configset_get_bool_or_int(struct config_set *cs, const char *key,
                                int *is_bool, int *dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value)) {
                *dest = git_config_bool_or_int(key, value, is_bool);
                return 0;
        } else
                return 1;
}

int git_configset_get_maybe_bool(struct config_set *cs, const char *key, int *dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value)) {
                *dest = git_parse_maybe_bool(value);
                if (*dest == -1)
                        return -1;
                return 0;
        } else
                return 1;
}

int git_configset_get_pathname(struct config_set *cs, const char *key, const char **dest)
{
        const char *value;
        if (!git_configset_get_value(cs, key, &value))
                return git_config_pathname(dest, key, value);
        else
                return 1;
}

/* Functions use to read configuration from a repository */
static void repo_read_config(struct repository *repo)
{
        struct config_options opts;

        opts.respect_includes = 1;
        opts.commondir = repo->commondir;
        opts.git_dir = repo->gitdir;

        if (!repo->config)
                repo->config = xcalloc(1, sizeof(struct config_set));
        else
                git_configset_clear(repo->config);

        git_configset_init(repo->config);

        if (config_with_options(config_set_callback, repo->config, NULL, &opts) < 0)
                /*
                 * config_with_options() normally returns only
                 * zero, as most errors are fatal, and
                 * non-fatal potential errors are guarded by "if"
                 * statements that are entered only when no error is
                 * possible.
                 *
                 * If we ever encounter a non-fatal error, it means
                 * something went really wrong and we should stop
                 * immediately.
                 */
                die(_("unknown error occurred while reading the configuration files"));
}

static void git_config_check_init(struct repository *repo)
{
        if (repo->config && repo->config->hash_initialized)
                return;
        repo_read_config(repo);
}

static void repo_config_clear(struct repository *repo)
{
        if (!repo->config || !repo->config->hash_initialized)
                return;
        git_configset_clear(repo->config);
}

void repo_config(struct repository *repo, config_fn_t fn, void *data)
{
        git_config_check_init(repo);
        configset_iter(repo->config, fn, data);
}

int repo_config_get_value(struct repository *repo,
                          const char *key, const char **value)
{
        git_config_check_init(repo);
        return git_configset_get_value(repo->config, key, value);
}

const struct string_list *repo_config_get_value_multi(struct repository *repo,
                                                      const char *key)
{
        git_config_check_init(repo);
        return git_configset_get_value_multi(repo->config, key);
}

int repo_config_get_string_const(struct repository *repo,
                                 const char *key, const char **dest)
{
        int ret;
        git_config_check_init(repo);
        ret = git_configset_get_string_const(repo->config, key, dest);
        if (ret < 0)
                git_die_config(key, NULL);
        return ret;
}

int repo_config_get_string(struct repository *repo,
                           const char *key, char **dest)
{
        git_config_check_init(repo);
        return repo_config_get_string_const(repo, key, (const char **)dest);
}

int repo_config_get_int(struct repository *repo,
                        const char *key, int *dest)
{
        git_config_check_init(repo);
        return git_configset_get_int(repo->config, key, dest);
}

int repo_config_get_ulong(struct repository *repo,
                          const char *key, unsigned long *dest)
{
        git_config_check_init(repo);
        return git_configset_get_ulong(repo->config, key, dest);
}

int repo_config_get_bool(struct repository *repo,
                         const char *key, int *dest)
{
        git_config_check_init(repo);
        return git_configset_get_bool(repo->config, key, dest);
}

int repo_config_get_bool_or_int(struct repository *repo,
                                const char *key, int *is_bool, int *dest)
{
        git_config_check_init(repo);
        return git_configset_get_bool_or_int(repo->config, key, is_bool, dest);
}

int repo_config_get_maybe_bool(struct repository *repo,
                               const char *key, int *dest)
{
        git_config_check_init(repo);
        return git_configset_get_maybe_bool(repo->config, key, dest);
}

int repo_config_get_pathname(struct repository *repo,
                             const char *key, const char **dest)
{
        int ret;
        git_config_check_init(repo);
        ret = git_configset_get_pathname(repo->config, key, dest);
        if (ret < 0)
                git_die_config(key, NULL);
        return ret;
}

/* Functions used historically to read configuration from 'the_repository' */
void git_config(config_fn_t fn, void *data)
{
        repo_config(the_repository, fn, data);
}

void git_config_clear(void)
{
        repo_config_clear(the_repository);
}

int git_config_get_value(const char *key, const char **value)
{
        return repo_config_get_value(the_repository, key, value);
}

const struct string_list *git_config_get_value_multi(const char *key)
{
        return repo_config_get_value_multi(the_repository, key);
}

int git_config_get_string_const(const char *key, const char **dest)
{
        return repo_config_get_string_const(the_repository, key, dest);
}

int git_config_get_string(const char *key, char **dest)
{
        return repo_config_get_string(the_repository, key, dest);
}

int git_config_get_int(const char *key, int *dest)
{
        return repo_config_get_int(the_repository, key, dest);
}

int git_config_get_ulong(const char *key, unsigned long *dest)
{
        return repo_config_get_ulong(the_repository, key, dest);
}

int git_config_get_bool(const char *key, int *dest)
{
        return repo_config_get_bool(the_repository, key, dest);
}

int git_config_get_bool_or_int(const char *key, int *is_bool, int *dest)
{
        return repo_config_get_bool_or_int(the_repository, key, is_bool, dest);
}

int git_config_get_maybe_bool(const char *key, int *dest)
{
        return repo_config_get_maybe_bool(the_repository, key, dest);
}

int git_config_get_pathname(const char *key, const char **dest)
{
        return repo_config_get_pathname(the_repository, key, dest);
}

int git_config_get_expiry(const char *key, const char **output)
{
        int ret = git_config_get_string_const(key, output);
        if (ret)
                return ret;
        if (strcmp(*output, "now")) {
                timestamp_t now = approxidate("now");
                if (approxidate(*output) >= now)
                        git_die_config(key, _("Invalid %s: '%s'"), key, *output);
        }
        return ret;
}

int git_config_get_expiry_in_days(const char *key, timestamp_t *expiry, timestamp_t now)
{
        char *expiry_string;
        intmax_t days;
        timestamp_t when;

        if (git_config_get_string(key, &expiry_string))
                return 1; /* no such thing */

        if (git_parse_signed(expiry_string, &days, maximum_signed_value_of_type(int))) {
                const int scale = 86400;
                *expiry = now - days * scale;
                return 0;
        }

        if (!parse_expiry_date(expiry_string, &when)) {
                *expiry = when;
                return 0;
        }
        return -1; /* thing exists but cannot be parsed */
}

int git_config_get_untracked_cache(void)
{
        int val = -1;
        const char *v;

        /* Hack for test programs like test-dump-untracked-cache */
        if (ignore_untracked_cache_config)
                return -1;

        if (!git_config_get_maybe_bool("core.untrackedcache", &val))
                return val;

        if (!git_config_get_value("core.untrackedcache", &v)) {
                if (!strcasecmp(v, "keep"))
                        return -1;

                error(_("unknown core.untrackedCache value '%s'; "
                        "using 'keep' default value"), v);
                return -1;
        }

        return -1; /* default value */
}

int git_config_get_split_index(void)
{
        int val;

        if (!git_config_get_maybe_bool("core.splitindex", &val))
                return val;

        return -1; /* default value */
}

int git_config_get_max_percent_split_change(void)
{
        int val = -1;

        if (!git_config_get_int("splitindex.maxpercentchange", &val)) {
                if (0 <= val && val <= 100)
                        return val;

                return error(_("splitIndex.maxPercentChange value '%d' "
                               "should be between 0 and 100"), val);
        }

        return -1; /* default value */
}

int git_config_get_fsmonitor(void)
{
        if (git_config_get_pathname("core.fsmonitor", &core_fsmonitor))
                core_fsmonitor = getenv("GIT_FSMONITOR_TEST");

        if (core_fsmonitor && !*core_fsmonitor)
                core_fsmonitor = NULL;

        if (core_fsmonitor)
                return 1;

        return 0;
}

NORETURN
void git_die_config_linenr(const char *key, const char *filename, int linenr)
{
        if (!filename)
                die(_("unable to parse '%s' from command-line config"), key);
        else
                die(_("bad config variable '%s' in file '%s' at line %d"),
                    key, filename, linenr);
}

NORETURN __attribute__((format(printf, 2, 3)))
void git_die_config(const char *key, const char *err, ...)
{
        const struct string_list *values;
        struct key_value_info *kv_info;

        if (err) {
                va_list params;
                va_start(params, err);
                vreportf("error: ", err, params);
                va_end(params);
        }
        values = git_config_get_value_multi(key);
        kv_info = values->items[values->nr - 1].util;
        git_die_config_linenr(key, kv_info->filename, kv_info->linenr);
}

/*
 * Find all the stuff for git_config_set() below.
 */

struct config_store_data {
        int baselen;
        char *key;
        int do_not_match;
        regex_t *value_regex;
        int multi_replace;
        struct {
                size_t begin, end;
                enum config_event_t type;
                int is_keys_section;
        } *parsed;
        unsigned int parsed_nr, parsed_alloc, *seen, seen_nr, seen_alloc;
        unsigned int key_seen:1, section_seen:1, is_keys_section:1;
};

static void config_store_data_clear(struct config_store_data *store)
{
        free(store->key);
        if (store->value_regex != NULL &&
            store->value_regex != CONFIG_REGEX_NONE) {
                regfree(store->value_regex);
                free(store->value_regex);
        }
        free(store->parsed);
        free(store->seen);
        memset(store, 0, sizeof(*store));
}

static int matches(const char *key, const char *value,
                   const struct config_store_data *store)
{
        if (strcmp(key, store->key))
                return 0; /* not ours */
        if (!store->value_regex)
                return 1; /* always matches */
        if (store->value_regex == CONFIG_REGEX_NONE)
                return 0; /* never matches */

        return store->do_not_match ^
                (value && !regexec(store->value_regex, value, 0, NULL, 0));
}

static int store_aux_event(enum config_event_t type,
                           size_t begin, size_t end, void *data)
{
        struct config_store_data *store = data;

        ALLOC_GROW(store->parsed, store->parsed_nr + 1, store->parsed_alloc);
        store->parsed[store->parsed_nr].begin = begin;
        store->parsed[store->parsed_nr].end = end;
        store->parsed[store->parsed_nr].type = type;

        if (type == CONFIG_EVENT_SECTION) {
                if (cf->var.len < 2 || cf->var.buf[cf->var.len - 1] != '.')
                        return error(_("invalid section name '%s'"), cf->var.buf);

                /* Is this the section we were looking for? */
                store->is_keys_section =
                        store->parsed[store->parsed_nr].is_keys_section =
                        cf->var.len - 1 == store->baselen &&
                        !strncasecmp(cf->var.buf, store->key, store->baselen);
                if (store->is_keys_section) {
                        store->section_seen = 1;
                        ALLOC_GROW(store->seen, store->seen_nr + 1,
                                   store->seen_alloc);
                        store->seen[store->seen_nr] = store->parsed_nr;
                }
        }

        store->parsed_nr++;

        return 0;
}

static int store_aux(const char *key, const char *value, void *cb)
{
        struct config_store_data *store = cb;

        if (store->key_seen) {
                if (matches(key, value, store)) {
                        if (store->seen_nr == 1 && store->multi_replace == 0) {
                                warning(_("%s has multiple values"), key);
                        }

                        ALLOC_GROW(store->seen, store->seen_nr + 1,
                                   store->seen_alloc);

                        store->seen[store->seen_nr] = store->parsed_nr;
                        store->seen_nr++;
                }
        } else if (store->is_keys_section) {
                /*
                 * Do not increment matches yet: this may not be a match, but we
                 * are in the desired section.
                 */
                ALLOC_GROW(store->seen, store->seen_nr + 1, store->seen_alloc);
                store->seen[store->seen_nr] = store->parsed_nr;
                store->section_seen = 1;

                if (matches(key, value, store)) {
                        store->seen_nr++;
                        store->key_seen = 1;
                }
        }

        return 0;
}

static int write_error(const char *filename)
{
        error(_("failed to write new configuration file %s"), filename);

        /* Same error code as "failed to rename". */
        return 4;
}

static struct strbuf store_create_section(const char *key,
                                          const struct config_store_data *store)
{
        const char *dot;
        int i;
        struct strbuf sb = STRBUF_INIT;

        dot = memchr(key, '.', store->baselen);
        if (dot) {
                strbuf_addf(&sb, "[%.*s \"", (int)(dot - key), key);
                for (i = dot - key + 1; i < store->baselen; i++) {
                        if (key[i] == '"' || key[i] == '\\')
                                strbuf_addch(&sb, '\\');
                        strbuf_addch(&sb, key[i]);
                }
                strbuf_addstr(&sb, "\"]\n");
        } else {
                strbuf_addf(&sb, "[%.*s]\n", store->baselen, key);
        }

        return sb;
}

static ssize_t write_section(int fd, const char *key,
                             const struct config_store_data *store)
{
        struct strbuf sb = store_create_section(key, store);
        ssize_t ret;

        ret = write_in_full(fd, sb.buf, sb.len);
        strbuf_release(&sb);

        return ret;
}

static ssize_t write_pair(int fd, const char *key, const char *value,
                          const struct config_store_data *store)
{
        int i;
        ssize_t ret;
        int length = strlen(key + store->baselen + 1);
        const char *quote = "";
        struct strbuf sb = STRBUF_INIT;

        /*
         * Check to see if the value needs to be surrounded with a dq pair.
         * Note that problematic characters are always backslash-quoted; this
         * check is about not losing leading or trailing SP and strings that
         * follow beginning-of-comment characters (i.e. ';' and '#') by the
         * configuration parser.
         */
        if (value[0] == ' ')
                quote = "\"";
        for (i = 0; value[i]; i++)
                if (value[i] == ';' || value[i] == '#')
                        quote = "\"";
        if (i && value[i - 1] == ' ')
                quote = "\"";

        strbuf_addf(&sb, "\t%.*s = %s",
                    length, key + store->baselen + 1, quote);

        for (i = 0; value[i]; i++)
                switch (value[i]) {
                case '\n':
                        strbuf_addstr(&sb, "\\n");
                        break;
                case '\t':
                        strbuf_addstr(&sb, "\\t");
                        break;
                case '"':
                case '\\':
                        strbuf_addch(&sb, '\\');
                        /* fallthrough */
                default:
                        strbuf_addch(&sb, value[i]);
                        break;
                }
        strbuf_addf(&sb, "%s\n", quote);

        ret = write_in_full(fd, sb.buf, sb.len);
        strbuf_release(&sb);

        return ret;
}

/*
 * If we are about to unset the last key(s) in a section, and if there are
 * no comments surrounding (or included in) the section, we will want to
 * extend begin/end to remove the entire section.
 *
 * Note: the parameter `seen_ptr` points to the index into the store.seen
 * array.  * This index may be incremented if a section has more than one
 * entry (which all are to be removed).
 */
static void maybe_remove_section(struct config_store_data *store,
                                 const char *contents,
                                 size_t *begin_offset, size_t *end_offset,
                                 int *seen_ptr)
{
        size_t begin;
        int i, seen, section_seen = 0;

        /*
         * First, ensure that this is the first key, and that there are no
         * comments before the entry nor before the section header.
         */
        seen = *seen_ptr;
        for (i = store->seen[seen]; i > 0; i--) {
                enum config_event_t type = store->parsed[i - 1].type;

                if (type == CONFIG_EVENT_COMMENT)
                        /* There is a comment before this entry or section */
                        return;
                if (type == CONFIG_EVENT_ENTRY) {
                        if (!section_seen)
                                /* This is not the section's first entry. */
                                return;
                        /* We encountered no comment before the section. */
                        break;
                }
                if (type == CONFIG_EVENT_SECTION) {
                        if (!store->parsed[i - 1].is_keys_section)
                                break;
                        section_seen = 1;
                }
        }
        begin = store->parsed[i].begin;

        /*
         * Next, make sure that we are removing he last key(s) in the section,
         * and that there are no comments that are possibly about the current
         * section.
         */
        for (i = store->seen[seen] + 1; i < store->parsed_nr; i++) {
                enum config_event_t type = store->parsed[i].type;

                if (type == CONFIG_EVENT_COMMENT)
                        return;
                if (type == CONFIG_EVENT_SECTION) {
                        if (store->parsed[i].is_keys_section)
                                continue;
                        break;
                }
                if (type == CONFIG_EVENT_ENTRY) {
                        if (++seen < store->seen_nr &&
                            i == store->seen[seen])
                                /* We want to remove this entry, too */
                                continue;
                        /* There is another entry in this section. */
                        return;
                }
        }

        /*
         * We are really removing the last entry/entries from this section, and
         * there are no enclosed or surrounding comments. Remove the entire,
         * now-empty section.
         */
        *seen_ptr = seen;
        *begin_offset = begin;
        if (i < store->parsed_nr)
                *end_offset = store->parsed[i].begin;
        else
                *end_offset = store->parsed[store->parsed_nr - 1].end;
}

int git_config_set_in_file_gently(const char *config_filename,
                                  const char *key, const char *value)
{
        return git_config_set_multivar_in_file_gently(config_filename, key, value, NULL, 0);
}

void git_config_set_in_file(const char *config_filename,
                            const char *key, const char *value)
{
        git_config_set_multivar_in_file(config_filename, key, value, NULL, 0);
}

int git_config_set_gently(const char *key, const char *value)
{
        return git_config_set_multivar_gently(key, value, NULL, 0);
}

void git_config_set(const char *key, const char *value)
{
        git_config_set_multivar(key, value, NULL, 0);
}

/*
 * If value==NULL, unset in (remove from) config,
 * if value_regex!=NULL, disregard key/value pairs where value does not match.
 * if value_regex==CONFIG_REGEX_NONE, do not match any existing values
 *     (only add a new one)
 * if multi_replace==0, nothing, or only one matching key/value is replaced,
 *     else all matching key/values (regardless how many) are removed,
 *     before the new pair is written.
 *
 * Returns 0 on success.
 *
 * This function does this:
 *
 * - it locks the config file by creating ".git/config.lock"
 *
 * - it then parses the config using store_aux() as validator to find
 *   the position on the key/value pair to replace. If it is to be unset,
 *   it must be found exactly once.
 *
 * - the config file is mmap()ed and the part before the match (if any) is
 *   written to the lock file, then the changed part and the rest.
 *
 * - the config file is removed and the lock file rename()d to it.
 *
 */
int git_config_set_multivar_in_file_gently(const char *config_filename,
                                           const char *key, const char *value,
                                           const char *value_regex,
                                           int multi_replace)
{
        int fd = -1, in_fd = -1;
        int ret;
        struct lock_file lock = LOCK_INIT;
        char *filename_buf = NULL;
        char *contents = NULL;
        size_t contents_sz;
        struct config_store_data store;

        memset(&store, 0, sizeof(store));

        /* parse-key returns negative; flip the sign to feed exit(3) */
        ret = 0 - git_config_parse_key(key, &store.key, &store.baselen);
        if (ret)
                goto out_free;

        store.multi_replace = multi_replace;

        if (!config_filename)
                config_filename = filename_buf = git_pathdup("config");

        /*
         * The lock serves a purpose in addition to locking: the new
         * contents of .git/config will be written into it.
         */
        fd = hold_lock_file_for_update(&lock, config_filename, 0);
        if (fd < 0) {
                error_errno(_("could not lock config file %s"), config_filename);
                ret = CONFIG_NO_LOCK;
                goto out_free;
        }

        /*
         * If .git/config does not exist yet, write a minimal version.
         */
        in_fd = open(config_filename, O_RDONLY);
        if ( in_fd < 0 ) {
                if ( ENOENT != errno ) {
                        error_errno(_("opening %s"), config_filename);
                        ret = CONFIG_INVALID_FILE; /* same as "invalid config file" */
                        goto out_free;
                }
                /* if nothing to unset, error out */
                if (value == NULL) {
                        ret = CONFIG_NOTHING_SET;
                        goto out_free;
                }

                free(store.key);
                store.key = xstrdup(key);
                if (write_section(fd, key, &store) < 0 ||
                    write_pair(fd, key, value, &store) < 0)
                        goto write_err_out;
        } else {
                struct stat st;
                size_t copy_begin, copy_end;
                int i, new_line = 0;
                struct config_options opts;

                if (value_regex == NULL)
                        store.value_regex = NULL;
                else if (value_regex == CONFIG_REGEX_NONE)
                        store.value_regex = CONFIG_REGEX_NONE;
                else {
                        if (value_regex[0] == '!') {
                                store.do_not_match = 1;
                                value_regex++;
                        } else
                                store.do_not_match = 0;

                        store.value_regex = (regex_t*)xmalloc(sizeof(regex_t));
                        if (regcomp(store.value_regex, value_regex,
                                        REG_EXTENDED)) {
                                error(_("invalid pattern: %s"), value_regex);
                                FREE_AND_NULL(store.value_regex);
                                ret = CONFIG_INVALID_PATTERN;
                                goto out_free;
                        }
                }

                ALLOC_GROW(store.parsed, 1, store.parsed_alloc);
                store.parsed[0].end = 0;

                memset(&opts, 0, sizeof(opts));
                opts.event_fn = store_aux_event;
                opts.event_fn_data = &store;

                /*
                 * After this, store.parsed will contain offsets of all the
                 * parsed elements, and store.seen will contain a list of
                 * matches, as indices into store.parsed.
                 *
                 * As a side effect, we make sure to transform only a valid
                 * existing config file.
                 */
                if (git_config_from_file_with_options(store_aux,
                                                      config_filename,
                                                      &store, &opts)) {
                        error(_("invalid config file %s"), config_filename);
                        ret = CONFIG_INVALID_FILE;
                        goto out_free;
                }

                /* if nothing to unset, or too many matches, error out */
                if ((store.seen_nr == 0 && value == NULL) ||
                    (store.seen_nr > 1 && multi_replace == 0)) {
                        ret = CONFIG_NOTHING_SET;
                        goto out_free;
                }

                if (fstat(in_fd, &st) == -1) {
                        error_errno(_("fstat on %s failed"), config_filename);
                        ret = CONFIG_INVALID_FILE;
                        goto out_free;
                }

                contents_sz = xsize_t(st.st_size);
                contents = xmmap_gently(NULL, contents_sz, PROT_READ,
                                        MAP_PRIVATE, in_fd, 0);
                if (contents == MAP_FAILED) {
                        if (errno == ENODEV && S_ISDIR(st.st_mode))
                                errno = EISDIR;
                        error_errno(_("unable to mmap '%s'"), config_filename);
                        ret = CONFIG_INVALID_FILE;
                        contents = NULL;
                        goto out_free;
                }
                close(in_fd);
                in_fd = -1;

                if (chmod(get_lock_file_path(&lock), st.st_mode & 07777) < 0) {
                        error_errno(_("chmod on %s failed"), get_lock_file_path(&lock));
                        ret = CONFIG_NO_WRITE;
                        goto out_free;
                }

                if (store.seen_nr == 0) {
                        if (!store.seen_alloc) {
                                /* Did not see key nor section */
                                ALLOC_GROW(store.seen, 1, store.seen_alloc);
                                store.seen[0] = store.parsed_nr
                                        - !!store.parsed_nr;
                        }
                        store.seen_nr = 1;
                }

                for (i = 0, copy_begin = 0; i < store.seen_nr; i++) {
                        size_t replace_end;
                        int j = store.seen[i];

                        new_line = 0;
                        if (!store.key_seen) {
                                copy_end = store.parsed[j].end;
                                /* include '\n' when copying section header */
                                if (copy_end > 0 && copy_end < contents_sz &&
                                    contents[copy_end - 1] != '\n' &&
                                    contents[copy_end] == '\n')
                                        copy_end++;
                                replace_end = copy_end;
                        } else {
                                replace_end = store.parsed[j].end;
                                copy_end = store.parsed[j].begin;
                                if (!value)
                                        maybe_remove_section(&store, contents,
                                                             &copy_end,
                                                             &replace_end, &i);
                                /*
                                 * Swallow preceding white-space on the same
                                 * line.
                                 */
                                while (copy_end > 0 ) {
                                        char c = contents[copy_end - 1];

                                        if (isspace(c) && c != '\n')
                                                copy_end--;
                                        else
                                                break;
                                }
                        }

                        if (copy_end > 0 && contents[copy_end-1] != '\n')
                                new_line = 1;

                        /* write the first part of the config */
                        if (copy_end > copy_begin) {
                                if (write_in_full(fd, contents + copy_begin,
                                                  copy_end - copy_begin) < 0)
                                        goto write_err_out;
                                if (new_line &&
                                    write_str_in_full(fd, "\n") < 0)
                                        goto write_err_out;
                        }
                        copy_begin = replace_end;
                }

                /* write the pair (value == NULL means unset) */
                if (value != NULL) {
                        if (!store.section_seen) {
                                if (write_section(fd, key, &store) < 0)
                                        goto write_err_out;
                        }
                        if (write_pair(fd, key, value, &store) < 0)
                                goto write_err_out;
                }

                /* write the rest of the config */
                if (copy_begin < contents_sz)
                        if (write_in_full(fd, contents + copy_begin,
                                          contents_sz - copy_begin) < 0)
                                goto write_err_out;

                munmap(contents, contents_sz);
                contents = NULL;
        }

        if (commit_lock_file(&lock) < 0) {
                error_errno(_("could not write config file %s"), config_filename);
                ret = CONFIG_NO_WRITE;
                goto out_free;
        }

        ret = 0;

        /* Invalidate the config cache */
        git_config_clear();

out_free:
        rollback_lock_file(&lock);
        free(filename_buf);
        if (contents)
                munmap(contents, contents_sz);
        if (in_fd >= 0)
                close(in_fd);
        config_store_data_clear(&store);
        return ret;

write_err_out:
        ret = write_error(get_lock_file_path(&lock));
        goto out_free;

}

void git_config_set_multivar_in_file(const char *config_filename,
                                     const char *key, const char *value,
                                     const char *value_regex, int multi_replace)
{
        if (!git_config_set_multivar_in_file_gently(config_filename, key, value,
                                                    value_regex, multi_replace))
                return;
        if (value)
                die(_("could not set '%s' to '%s'"), key, value);
        else
                die(_("could not unset '%s'"), key);
}

int git_config_set_multivar_gently(const char *key, const char *value,
                                   const char *value_regex, int multi_replace)
{
        return git_config_set_multivar_in_file_gently(NULL, key, value, value_regex,
                                                      multi_replace);
}

void git_config_set_multivar(const char *key, const char *value,
                             const char *value_regex, int multi_replace)
{
        git_config_set_multivar_in_file(NULL, key, value, value_regex,
                                        multi_replace);
}

static int section_name_match (const char *buf, const char *name)
{
        int i = 0, j = 0, dot = 0;
        if (buf[i] != '[')
                return 0;
        for (i = 1; buf[i] && buf[i] != ']'; i++) {
                if (!dot && isspace(buf[i])) {
                        dot = 1;
                        if (name[j++] != '.')
                                break;
                        for (i++; isspace(buf[i]); i++)
                                ; /* do nothing */
                        if (buf[i] != '"')
                                break;
                        continue;
                }
                if (buf[i] == '\\' && dot)
                        i++;
                else if (buf[i] == '"' && dot) {
                        for (i++; isspace(buf[i]); i++)
                                ; /* do_nothing */
                        break;
                }
                if (buf[i] != name[j++])
                        break;
        }
        if (buf[i] == ']' && name[j] == 0) {
                /*
                 * We match, now just find the right length offset by
                 * gobbling up any whitespace after it, as well
                 */
                i++;
                for (; buf[i] && isspace(buf[i]); i++)
                        ; /* do nothing */
                return i;
        }
        return 0;
}

static int section_name_is_ok(const char *name)
{
        /* Empty section names are bogus. */
        if (!*name)
                return 0;

        /*
         * Before a dot, we must be alphanumeric or dash. After the first dot,
         * anything goes, so we can stop checking.
         */
        for (; *name && *name != '.'; name++)
                if (*name != '-' && !isalnum(*name))
                        return 0;
        return 1;
}

/* if new_name == NULL, the section is removed instead */
static int git_config_copy_or_rename_section_in_file(const char *config_filename,
                                      const char *old_name,
                                      const char *new_name, int copy)
{
        int ret = 0, remove = 0;
        char *filename_buf = NULL;
        struct lock_file lock = LOCK_INIT;
        int out_fd;
        char buf[1024];
        FILE *config_file = NULL;
        struct stat st;
        struct strbuf copystr = STRBUF_INIT;
        struct config_store_data store;

        memset(&store, 0, sizeof(store));

        if (new_name && !section_name_is_ok(new_name)) {
                ret = error(_("invalid section name: %s"), new_name);
                goto out_no_rollback;
        }

        if (!config_filename)
                config_filename = filename_buf = git_pathdup("config");

        out_fd = hold_lock_file_for_update(&lock, config_filename, 0);
        if (out_fd < 0) {
                ret = error(_("could not lock config file %s"), config_filename);
                goto out;
        }

        if (!(config_file = fopen(config_filename, "rb"))) {
                ret = warn_on_fopen_errors(config_filename);
                if (ret)
                        goto out;
                /* no config file means nothing to rename, no error */
                goto commit_and_out;
        }

        if (fstat(fileno(config_file), &st) == -1) {
                ret = error_errno(_("fstat on %s failed"), config_filename);
                goto out;
        }

        if (chmod(get_lock_file_path(&lock), st.st_mode & 07777) < 0) {
                ret = error_errno(_("chmod on %s failed"),
                                  get_lock_file_path(&lock));
                goto out;
        }

        while (fgets(buf, sizeof(buf), config_file)) {
                int i;
                int length;
                int is_section = 0;
                char *output = buf;
                for (i = 0; buf[i] && isspace(buf[i]); i++)
                        ; /* do nothing */
                if (buf[i] == '[') {
                        /* it's a section */
                        int offset;
                        is_section = 1;

                        /*
                         * When encountering a new section under -c we
                         * need to flush out any section we're already
                         * coping and begin anew. There might be
                         * multiple [branch "$name"] sections.
                         */
                        if (copystr.len > 0) {
                                if (write_in_full(out_fd, copystr.buf, copystr.len) < 0) {
                                        ret = write_error(get_lock_file_path(&lock));
                                        goto out;
                                }
                                strbuf_reset(&copystr);
                        }

                        offset = section_name_match(&buf[i], old_name);
                        if (offset > 0) {
                                ret++;
                                if (new_name == NULL) {
                                        remove = 1;
                                        continue;
                                }
                                store.baselen = strlen(new_name);
                                if (!copy) {
                                        if (write_section(out_fd, new_name, &store) < 0) {
                                                ret = write_error(get_lock_file_path(&lock));
                                                goto out;
                                        }
                                        /*
                                         * We wrote out the new section, with
                                         * a newline, now skip the old
                                         * section's length
                                         */
                                        output += offset + i;
                                        if (strlen(output) > 0) {
                                                /*
                                                 * More content means there's
                                                 * a declaration to put on the
                                                 * next line; indent with a
                                                 * tab
                                                 */
                                                output -= 1;
                                                output[0] = '\t';
                                        }
                                } else {
                                        copystr = store_create_section(new_name, &store);
                                }
                        }
                        remove = 0;
                }
                if (remove)
                        continue;
                length = strlen(output);

                if (!is_section && copystr.len > 0) {
                        strbuf_add(&copystr, output, length);
                }

                if (write_in_full(out_fd, output, length) < 0) {
                        ret = write_error(get_lock_file_path(&lock));
                        goto out;
                }
        }

        /*
         * Copy a trailing section at the end of the config, won't be
         * flushed by the usual "flush because we have a new section
         * logic in the loop above.
         */
        if (copystr.len > 0) {
                if (write_in_full(out_fd, copystr.buf, copystr.len) < 0) {
                        ret = write_error(get_lock_file_path(&lock));
                        goto out;
                }
                strbuf_reset(&copystr);
        }

        fclose(config_file);
        config_file = NULL;
commit_and_out:
        if (commit_lock_file(&lock) < 0)
                ret = error_errno(_("could not write config file %s"),
                                  config_filename);
out:
        if (config_file)
                fclose(config_file);
        rollback_lock_file(&lock);
out_no_rollback:
        free(filename_buf);
        config_store_data_clear(&store);
        return ret;
}

int git_config_rename_section_in_file(const char *config_filename,
                                      const char *old_name, const char *new_name)
{
        return git_config_copy_or_rename_section_in_file(config_filename,
                                         old_name, new_name, 0);
}

int git_config_rename_section(const char *old_name, const char *new_name)
{
        return git_config_rename_section_in_file(NULL, old_name, new_name);
}

int git_config_copy_section_in_file(const char *config_filename,
                                      const char *old_name, const char *new_name)
{
        return git_config_copy_or_rename_section_in_file(config_filename,
                                         old_name, new_name, 1);
}

int git_config_copy_section(const char *old_name, const char *new_name)
{
        return git_config_copy_section_in_file(NULL, old_name, new_name);
}

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

int parse_config_key(const char *var,
                     const char *section,
                     const char **subsection, int *subsection_len,
                     const char **key)
{
        const char *dot;

        /* Does it start with "section." ? */
        if (!skip_prefix(var, section, &var) || *var != '.')
                return -1;

        /*
         * Find the key; we don't know yet if we have a subsection, but we must
         * parse backwards from the end, since the subsection may have dots in
         * it, too.
         */
        dot = strrchr(var, '.');
        *key = dot + 1;

        /* Did we have a subsection at all? */
        if (dot == var) {
                if (subsection) {
                        *subsection = NULL;
                        *subsection_len = 0;
                }
        }
        else {
                if (!subsection)
                        return -1;
                *subsection = var + 1;
                *subsection_len = dot - *subsection;
        }

        return 0;
}

const char *current_config_origin_type(void)
{
        int type;
        if (current_config_kvi)
                type = current_config_kvi->origin_type;
        else if(cf)
                type = cf->origin_type;
        else
                BUG("current_config_origin_type called outside config callback");

        switch (type) {
        case CONFIG_ORIGIN_BLOB:
                return "blob";
        case CONFIG_ORIGIN_FILE:
                return "file";
        case CONFIG_ORIGIN_STDIN:
                return "standard input";
        case CONFIG_ORIGIN_SUBMODULE_BLOB:
                return "submodule-blob";
        case CONFIG_ORIGIN_CMDLINE:
                return "command line";
        default:
                BUG("unknown config origin type");
        }
}

const char *current_config_name(void)
{
        const char *name;
        if (current_config_kvi)
                name = current_config_kvi->filename;
        else if (cf)
                name = cf->name;
        else
                BUG("current_config_name called outside config callback");
        return name ? name : "";
}

enum config_scope current_config_scope(void)
{
        if (current_config_kvi)
                return current_config_kvi->scope;
        else
                return current_parsing_scope;
}

int lookup_config(const char **mapping, int nr_mapping, const char *var)
{
        int i;

        for (i = 0; i < nr_mapping; i++) {
                const char *name = mapping[i];

                if (name && !strcasecmp(var, name))
                        return i;
        }
        return -1;
}