diffcore-order: fix leaking buffer when parsing orderfiles

[alt-git.git] / config.c

/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 * Copyright (C) Johannes Schindelin, 2005
 *
 */

#include "git-compat-util.h"
#include "abspath.h"
#include "advice.h"
#include "date.h"
#include "branch.h"
#include "config.h"
#include "parse.h"
#include "convert.h"
#include "environment.h"
#include "gettext.h"
#include "ident.h"
#include "repository.h"
#include "lockfile.h"
#include "mailmap.h"
#include "attr.h"
#include "exec-cmd.h"
#include "strbuf.h"
#include "quote.h"
#include "hashmap.h"
#include "string-list.h"
#include "object-name.h"
#include "object-store-ll.h"
#include "pager.h"
#include "path.h"
#include "utf8.h"
#include "color.h"
#include "refs.h"
#include "setup.h"
#include "strvec.h"
#include "trace2.h"
#include "wildmatch.h"
#include "ws.h"
#include "write-or-die.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;
        size_t total_len;
        struct strbuf value;
        struct strbuf var;
        unsigned subsection_case_sensitive : 1;

        int (*do_fgetc)(struct config_source *c);
        int (*do_ungetc)(int c, struct config_source *conf);
        long (*do_ftell)(struct config_source *c);
};
#define CONFIG_SOURCE_INIT { 0 }

static int pack_compression_seen;
static int zlib_compression_seen;

/*
 * Config that comes from trusted scopes, namely:
 * - CONFIG_SCOPE_SYSTEM (e.g. /etc/gitconfig)
 * - CONFIG_SCOPE_GLOBAL (e.g. $HOME/.gitconfig, $XDG_CONFIG_HOME/git)
 * - CONFIG_SCOPE_COMMAND (e.g. "-c" option, environment variables)
 *
 * This is declared here for code cleanliness, but unlike the other
 * static variables, this does not hold config parser state.
 */
static struct config_set protected_config;

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;
}

struct config_include_data {
        int depth;
        config_fn_t fn;
        void *data;
        const struct config_options *opts;
        const struct git_config_source *config_source;
        struct repository *repo;

        /*
         * All remote URLs discovered when reading all config files.
         */
        struct string_list *remote_urls;
};
#define CONFIG_INCLUDE_INIT { 0 }

static int git_config_include(const char *var, const char *value,
                              const struct config_context *ctx, void *data);

#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"
"This might be due to circular includes.");
static int handle_path_include(const struct key_value_info *kvi,
                               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 = interpolate_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 (!kvi || !kvi->path) {
                        ret = error(_("relative config includes must come from files"));
                        goto cleanup;
                }

                slash = find_last_dir_sep(kvi->path);
                if (slash)
                        strbuf_add(&buf, kvi->path, slash - kvi->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,
                            !kvi ? "<unknown>" :
                            kvi->filename ? kvi->filename :
                            "the command line");
                ret = git_config_from_file_with_options(git_config_include, path, inc,
                                                        kvi->scope, NULL);
                inc->depth--;
        }
cleanup:
        strbuf_release(&buf);
        free(expanded);
        return ret;
}

static void add_trailing_starstar_for_dir(struct strbuf *pat)
{
        if (pat->len && is_dir_sep(pat->buf[pat->len - 1]))
                strbuf_addstr(pat, "**");
}

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

        expanded = interpolate_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 (!kvi || !kvi->path)
                        return error(_("relative config include "
                                       "conditionals must come from files"));

                strbuf_realpath(&path, kvi->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_insertstr(pat, 0, "**/");

        add_trailing_starstar_for_dir(pat);

        strbuf_release(&path);
        return prefix;
}

static int include_by_gitdir(const struct key_value_info *kvi,
                             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(kvi, &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,
                         WM_PATHNAME | (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_by_branch(struct config_include_data *data,
                             const char *cond, size_t cond_len)
{
        int flags;
        int ret;
        struct strbuf pattern = STRBUF_INIT;
        const char *refname = (!data->repo || !data->repo->gitdir) ?
                NULL : refs_resolve_ref_unsafe(get_main_ref_store(data->repo),
                                               "HEAD", 0, NULL, &flags);
        const char *shortname;

        if (!refname || !(flags & REF_ISSYMREF) ||
                        !skip_prefix(refname, "refs/heads/", &shortname))
                return 0;

        strbuf_add(&pattern, cond, cond_len);
        add_trailing_starstar_for_dir(&pattern);
        ret = !wildmatch(pattern.buf, shortname, WM_PATHNAME);
        strbuf_release(&pattern);
        return ret;
}

static int add_remote_url(const char *var, const char *value,
                          const struct config_context *ctx UNUSED, void *data)
{
        struct string_list *remote_urls = data;
        const char *remote_name;
        size_t remote_name_len;
        const char *key;

        if (!parse_config_key(var, "remote", &remote_name, &remote_name_len,
                              &key) &&
            remote_name &&
            !strcmp(key, "url"))
                string_list_append(remote_urls, value);
        return 0;
}

static void populate_remote_urls(struct config_include_data *inc)
{
        struct config_options opts;

        opts = *inc->opts;
        opts.unconditional_remote_url = 1;

        inc->remote_urls = xmalloc(sizeof(*inc->remote_urls));
        string_list_init_dup(inc->remote_urls);
        config_with_options(add_remote_url, inc->remote_urls,
                            inc->config_source, inc->repo, &opts);
}

static int forbid_remote_url(const char *var, const char *value UNUSED,
                             const struct config_context *ctx UNUSED,
                             void *data UNUSED)
{
        const char *remote_name;
        size_t remote_name_len;
        const char *key;

        if (!parse_config_key(var, "remote", &remote_name, &remote_name_len,
                              &key) &&
            remote_name &&
            !strcmp(key, "url"))
                die(_("remote URLs cannot be configured in file directly or indirectly included by includeIf.hasconfig:remote.*.url"));
        return 0;
}

static int at_least_one_url_matches_glob(const char *glob, int glob_len,
                                         struct string_list *remote_urls)
{
        struct strbuf pattern = STRBUF_INIT;
        struct string_list_item *url_item;
        int found = 0;

        strbuf_add(&pattern, glob, glob_len);
        for_each_string_list_item(url_item, remote_urls) {
                if (!wildmatch(pattern.buf, url_item->string, WM_PATHNAME)) {
                        found = 1;
                        break;
                }
        }
        strbuf_release(&pattern);
        return found;
}

static int include_by_remote_url(struct config_include_data *inc,
                const char *cond, size_t cond_len)
{
        if (inc->opts->unconditional_remote_url)
                return 1;
        if (!inc->remote_urls)
                populate_remote_urls(inc);
        return at_least_one_url_matches_glob(cond, cond_len,
                                             inc->remote_urls);
}

static int include_condition_is_true(const struct key_value_info *kvi,
                                     struct config_include_data *inc,
                                     const char *cond, size_t cond_len)
{
        const struct config_options *opts = inc->opts;

        if (skip_prefix_mem(cond, cond_len, "gitdir:", &cond, &cond_len))
                return include_by_gitdir(kvi, opts, cond, cond_len, 0);
        else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
                return include_by_gitdir(kvi, opts, cond, cond_len, 1);
        else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
                return include_by_branch(inc, cond, cond_len);
        else if (skip_prefix_mem(cond, cond_len, "hasconfig:remote.*.url:", &cond,
                                   &cond_len))
                return include_by_remote_url(inc, cond, cond_len);

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

static int git_config_include(const char *var, const char *value,
                              const struct config_context *ctx,
                              void *data)
{
        struct config_include_data *inc = data;
        const char *cond, *key;
        size_t 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, ctx, inc->data);
        if (ret < 0)
                return ret;

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

        if (!parse_config_key(var, "includeif", &cond, &cond_len, &key) &&
            cond && include_condition_is_true(ctx->kvi, inc, cond, cond_len) &&
            !strcmp(key, "path")) {
                config_fn_t old_fn = inc->fn;

                if (inc->opts->unconditional_remote_url)
                        inc->fn = forbid_remote_url;
                ret = handle_path_include(ctx->kvi, value, inc);
                inc->fn = old_fn;
        }

        return ret;
}

static void git_config_push_split_parameter(const char *key, const char *value)
{
        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, key);
        strbuf_addch(&env, '=');
        if (value)
                sq_quote_buf(&env, value);
        setenv(CONFIG_DATA_ENVIRONMENT, env.buf, 1);
        strbuf_release(&env);
}

void git_config_push_parameter(const char *text)
{
        const char *value;

        /*
         * When we see:
         *
         *   section.subsection=with=equals.key=value
         *
         * we cannot tell if it means:
         *
         *   [section "subsection=with=equals"]
         *   key = value
         *
         * or:
         *
         *   [section]
         *   subsection = with=equals.key=value
         *
         * We parse left-to-right for the first "=", meaning we'll prefer to
         * keep the value intact over the subsection. This is historical, but
         * also sensible since values are more likely to contain odd or
         * untrusted input than a section name.
         *
         * A missing equals is explicitly allowed (as a bool-only entry).
         */
        value = strchr(text, '=');
        if (value) {
                char *key = xmemdupz(text, value - text);
                git_config_push_split_parameter(key, value + 1);
                free(key);
        } else {
                git_config_push_split_parameter(text, NULL);
        }
}

void git_config_push_env(const char *spec)
{
        char *key;
        const char *env_name;
        const char *env_value;

        env_name = strrchr(spec, '=');
        if (!env_name)
                die(_("invalid config format: %s"), spec);
        key = xmemdupz(spec, env_name - spec);
        env_name++;
        if (!*env_name)
                die(_("missing environment variable name for configuration '%.*s'"),
                    (int)(env_name - spec - 1), spec);

        env_value = getenv(env_name);
        if (!env_value)
                die(_("missing environment variable '%s' for configuration '%.*s'"),
                    env_name, (int)(env_name - spec - 1), spec);

        git_config_push_split_parameter(key, env_value);
        free(key);
}

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 size_t which will hold the length of the
 *           section + subsection part, can be NULL
 */
int git_config_parse_key(const char *key, char **store_key, size_t *baselen_)
{
        size_t i, baselen;
        int dot;
        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) {
                error(_("key does not contain a section: %s"), key);
                return -CONFIG_NO_SECTION_OR_NAME;
        }

        if (!last_dot[1]) {
                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.
         */
        *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))) {
                                error(_("invalid key: %s"), key);
                                goto out_free_ret_1;
                        }
                        c = tolower(c);
                } else if (c == '\n') {
                        error(_("invalid key (newline): %s"), key);
                        goto out_free_ret_1;
                }
                (*store_key)[i] = c;
        }

        return 0;

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

static int config_parse_pair(const char *key, const char *value,
                             struct key_value_info *kvi,
                             config_fn_t fn, void *data)
{
        char *canonical_name;
        int ret;
        struct config_context ctx = {
                .kvi = kvi,
        };

        if (!strlen(key))
                return error(_("empty config key"));
        if (git_config_parse_key(key, &canonical_name, NULL))
                return -1;

        ret = (fn(canonical_name, value, &ctx, data) < 0) ? -1 : 0;
        free(canonical_name);
        return ret;
}


/* for values read from `git_config_from_parameters()` */
void kvi_from_param(struct key_value_info *out)
{
        out->filename = NULL;
        out->linenr = -1;
        out->origin_type = CONFIG_ORIGIN_CMDLINE;
        out->scope = CONFIG_SCOPE_COMMAND;
        out->path = NULL;
}

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

        kvi_from_param(&kvi);

        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);
        }

        ret = config_parse_pair(pair[0]->buf, value, &kvi, fn, data);
        strbuf_list_free(pair);
        return ret;
}

static int parse_config_env_list(char *env, struct key_value_info *kvi,
                                 config_fn_t fn, void *data)
{
        char *cur = env;
        while (cur && *cur) {
                const char *key = sq_dequote_step(cur, &cur);
                if (!key)
                        return error(_("bogus format in %s"),
                                     CONFIG_DATA_ENVIRONMENT);

                if (!cur || isspace(*cur)) {
                        /* old-style 'key=value' */
                        if (git_config_parse_parameter(key, fn, data) < 0)
                                return -1;
                }
                else if (*cur == '=') {
                        /* new-style 'key'='value' */
                        const char *value;

                        cur++;
                        if (*cur == '\'') {
                                /* quoted value */
                                value = sq_dequote_step(cur, &cur);
                                if (!value || (cur && !isspace(*cur))) {
                                        return error(_("bogus format in %s"),
                                                     CONFIG_DATA_ENVIRONMENT);
                                }
                        } else if (!*cur || isspace(*cur)) {
                                /* implicit bool: 'key'= */
                                value = NULL;
                        } else {
                                return error(_("bogus format in %s"),
                                             CONFIG_DATA_ENVIRONMENT);
                        }

                        if (config_parse_pair(key, value, kvi, fn, data) < 0)
                                return -1;
                }
                else {
                        /* unknown format */
                        return error(_("bogus format in %s"),
                                     CONFIG_DATA_ENVIRONMENT);
                }

                if (cur) {
                        while (isspace(*cur))
                                cur++;
                }
        }
        return 0;
}

int git_config_from_parameters(config_fn_t fn, void *data)
{
        const char *env;
        struct strbuf envvar = STRBUF_INIT;
        struct strvec to_free = STRVEC_INIT;
        int ret = 0;
        char *envw = NULL;
        struct key_value_info kvi = KVI_INIT;

        kvi_from_param(&kvi);
        env = getenv(CONFIG_COUNT_ENVIRONMENT);
        if (env) {
                unsigned long count;
                char *endp;
                int i;

                count = strtoul(env, &endp, 10);
                if (*endp) {
                        ret = error(_("bogus count in %s"), CONFIG_COUNT_ENVIRONMENT);
                        goto out;
                }
                if (count > INT_MAX) {
                        ret = error(_("too many entries in %s"), CONFIG_COUNT_ENVIRONMENT);
                        goto out;
                }

                for (i = 0; i < count; i++) {
                        const char *key, *value;

                        strbuf_addf(&envvar, "GIT_CONFIG_KEY_%d", i);
                        key = getenv_safe(&to_free, envvar.buf);
                        if (!key) {
                                ret = error(_("missing config key %s"), envvar.buf);
                                goto out;
                        }
                        strbuf_reset(&envvar);

                        strbuf_addf(&envvar, "GIT_CONFIG_VALUE_%d", i);
                        value = getenv_safe(&to_free, envvar.buf);
                        if (!value) {
                                ret = error(_("missing config value %s"), envvar.buf);
                                goto out;
                        }
                        strbuf_reset(&envvar);

                        if (config_parse_pair(key, value, &kvi, fn, data) < 0) {
                                ret = -1;
                                goto out;
                        }
                }
        }

        env = getenv(CONFIG_DATA_ENVIRONMENT);
        if (env) {
                /* sq_dequote will write over it */
                envw = xstrdup(env);
                if (parse_config_env_list(envw, &kvi, fn, data) < 0) {
                        ret = -1;
                        goto out;
                }
        }

out:
        strbuf_release(&envvar);
        strvec_clear(&to_free);
        free(envw);
        return ret;
}

static int get_next_char(struct config_source *cs)
{
        int c = cs->do_fgetc(cs);

        if (c == '\r') {
                /* DOS like systems */
                c = cs->do_fgetc(cs);
                if (c != '\n') {
                        if (c != EOF)
                                cs->do_ungetc(c, cs);
                        c = '\r';
                }
        }

        if (c != EOF && ++cs->total_len > INT_MAX) {
                /*
                 * This is an absurdly long config file; refuse to parse
                 * further in order to protect downstream code from integer
                 * overflows. Note that we can't return an error specifically,
                 * but we can mark EOF and put trash in the return value,
                 * which will trigger a parse error.
                 */
                cs->eof = 1;
                return 0;
        }

        if (c == '\n')
                cs->linenr++;
        if (c == EOF) {
                cs->eof = 1;
                cs->linenr++;
                c = '\n';
        }
        return c;
}

static char *parse_value(struct config_source *cs)
{
        int quote = 0, comment = 0;
        size_t trim_len = 0;

        strbuf_reset(&cs->value);
        for (;;) {
                int c = get_next_char(cs);
                if (c == '\n') {
                        if (quote) {
                                cs->linenr--;
                                return NULL;
                        }
                        if (trim_len)
                                strbuf_setlen(&cs->value, trim_len);
                        return cs->value.buf;
                }
                if (comment)
                        continue;
                if (isspace(c) && !quote) {
                        if (!trim_len)
                                trim_len = cs->value.len;
                        if (cs->value.len)
                                strbuf_addch(&cs->value, c);
                        continue;
                }
                if (!quote) {
                        if (c == ';' || c == '#') {
                                comment = 1;
                                continue;
                        }
                }
                if (trim_len)
                        trim_len = 0;
                if (c == '\\') {
                        c = get_next_char(cs);
                        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(&cs->value, c);
                        continue;
                }
                if (c == '"') {
                        quote = 1 - quote;
                        continue;
                }
                strbuf_addch(&cs->value, c);
        }
}

static int get_value(struct config_source *cs, struct key_value_info *kvi,
                     config_fn_t fn, void *data, struct strbuf *name)
{
        int c;
        char *value;
        int ret;
        struct config_context ctx = {
                .kvi = kvi,
        };

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

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

        value = NULL;
        if (c != '\n') {
                if (c != '=')
                        return -1;
                value = parse_value(cs);
                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.
         */
        cs->linenr--;
        kvi->linenr = cs->linenr;
        ret = fn(name->buf, value, &ctx, data);
        if (ret >= 0)
                cs->linenr++;
        return ret;
}

static int get_extended_base_var(struct config_source *cs, struct strbuf *name,
                                 int c)
{
        cs->subsection_case_sensitive = 0;
        do {
                if (c == '\n')
                        goto error_incomplete_line;
                c = get_next_char(cs);
        } while (isspace(c));

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

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

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

static int get_base_var(struct config_source *cs, struct strbuf *name)
{
        cs->subsection_case_sensitive = 1;
        for (;;) {
                int c = get_next_char(cs);
                if (cs->eof)
                        return -1;
                if (c == ']')
                        return 0;
                if (isspace(c))
                        return get_extended_base_var(cs, 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(struct config_source *cs, 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 = cs->do_ftell(cs);
        /*
         * 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, cs, data->opts->event_fn_data) < 0)
                return -1;

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

        return 0;
}

static void kvi_from_source(struct config_source *cs,
                            enum config_scope scope,
                            struct key_value_info *out)
{
        out->filename = strintern(cs->name);
        out->origin_type = cs->origin_type;
        out->linenr = cs->linenr;
        out->scope = scope;
        out->path = cs->path;
}

static int git_parse_source(struct config_source *cs, config_fn_t fn,
                            struct key_value_info *kvi, void *data,
                            const struct config_options *opts)
{
        int comment = 0;
        size_t baselen = 0;
        struct strbuf *var = &cs->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(cs);
                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 (cs->eof) {
                                if (do_event(cs, CONFIG_EVENT_EOF, &event_data) < 0)
                                        return -1;
                                return 0;
                        }
                        if (do_event(cs, CONFIG_EVENT_WHITESPACE, &event_data) < 0)
                                return -1;
                        comment = 0;
                        continue;
                }
                if (comment)
                        continue;
                if (isspace(c)) {
                        if (do_event(cs, CONFIG_EVENT_WHITESPACE, &event_data) < 0)
                                        return -1;
                        continue;
                }
                if (c == '#' || c == ';') {
                        if (do_event(cs, CONFIG_EVENT_COMMENT, &event_data) < 0)
                                        return -1;
                        comment = 1;
                        continue;
                }
                if (c == '[') {
                        if (do_event(cs, CONFIG_EVENT_SECTION, &event_data) < 0)
                                        return -1;

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

                if (do_event(cs, 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(cs, kvi, fn, data, var) < 0)
                        break;
        }

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

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

        switch (opts && opts->error_action ?
                opts->error_action :
                cs->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;
}

NORETURN
static void die_bad_number(const char *name, const char *value,
                           const struct key_value_info *kvi)
{
        const char *error_type = (errno == ERANGE) ?
                N_("out of range") : N_("invalid unit");
        const char *bad_numeric = N_("bad numeric config value '%s' for '%s': %s");

        if (!kvi)
                BUG("kvi should not be NULL");

        if (!value)
                value = "";

        if (!kvi->filename)
                die(_(bad_numeric), value, name, _(error_type));

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

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

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

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

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

double git_config_double(const char *name, const char *value,
                         const struct key_value_info *kvi)
{
        double ret;
        if (!git_parse_double(value, &ret))
                die_bad_number(name, value, kvi);
        return ret;
}

static const struct fsync_component_name {
        const char *name;
        enum fsync_component component_bits;
} fsync_component_names[] = {
        { "loose-object", FSYNC_COMPONENT_LOOSE_OBJECT },
        { "pack", FSYNC_COMPONENT_PACK },
        { "pack-metadata", FSYNC_COMPONENT_PACK_METADATA },
        { "commit-graph", FSYNC_COMPONENT_COMMIT_GRAPH },
        { "index", FSYNC_COMPONENT_INDEX },
        { "objects", FSYNC_COMPONENTS_OBJECTS },
        { "reference", FSYNC_COMPONENT_REFERENCE },
        { "derived-metadata", FSYNC_COMPONENTS_DERIVED_METADATA },
        { "committed", FSYNC_COMPONENTS_COMMITTED },
        { "added", FSYNC_COMPONENTS_ADDED },
        { "all", FSYNC_COMPONENTS_ALL },
};

static enum fsync_component parse_fsync_components(const char *var, const char *string)
{
        enum fsync_component current = FSYNC_COMPONENTS_PLATFORM_DEFAULT;
        enum fsync_component positive = 0, negative = 0;

        while (string) {
                int i;
                size_t len;
                const char *ep;
                int negated = 0;
                int found = 0;

                string = string + strspn(string, ", \t\n\r");
                ep = strchrnul(string, ',');
                len = ep - string;
                if (!strcmp(string, "none")) {
                        current = FSYNC_COMPONENT_NONE;
                        goto next_name;
                }

                if (*string == '-') {
                        negated = 1;
                        string++;
                        len--;
                        if (!len)
                                warning(_("invalid value for variable %s"), var);
                }

                if (!len)
                        break;

                for (i = 0; i < ARRAY_SIZE(fsync_component_names); ++i) {
                        const struct fsync_component_name *n = &fsync_component_names[i];

                        if (strncmp(n->name, string, len))
                                continue;

                        found = 1;
                        if (negated)
                                negative |= n->component_bits;
                        else
                                positive |= n->component_bits;
                }

                if (!found) {
                        char *component = xstrndup(string, len);
                        warning(_("ignoring unknown core.fsync component '%s'"), component);
                        free(component);
                }

next_name:
                string = ep;
        }

        return (current & ~negative) | positive;
}

int git_config_bool_or_int(const char *name, const char *value,
                           const struct key_value_info *kvi, 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, kvi);
}

int git_config_bool(const char *name, const char *value)
{
        int v = git_parse_maybe_bool(value);
        if (v < 0)
                die(_("bad boolean config value '%s' for '%s'"), value, name);
        return v;
}

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

int git_config_pathname(char **dest, const char *var, const char *value)
{
        if (!value)
                return config_error_nonbool(var);
        *dest = interpolate_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,
                                   const struct config_context *ctx, void *cb)
{
        /* 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 (!value)
                        return config_error_nonbool(var);
                if (!strcasecmp(value, "default"))
                        check_stat = 1;
                else if (!strcasecmp(value, "minimal"))
                        check_stat = 0;
                else
                        return error(_("invalid value for '%s': '%s'"),
                                     var, value);
        }

        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")) {
                FREE_AND_NULL(git_attributes_file);
                return git_config_pathname(&git_attributes_file, var, value);
        }

        if (!strcmp(var, "core.hookspath")) {
                FREE_AND_NULL(git_hooks_path);
                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 if (!git_parse_maybe_bool_text(value))
                        default_abbrev = GIT_MAX_HEXSZ;
                else {
                        int abbrev = git_config_int(var, value, ctx->kvi);
                        if (abbrev < minimum_abbrev)
                                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, ctx->kvi);
                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, ctx->kvi);
                if (level == -1)
                        level = Z_DEFAULT_COMPRESSION;
                else if (level < 0 || level > Z_BEST_COMPRESSION)
                        die(_("bad zlib compression level %d"), level);
                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, ctx->kvi);

                /* 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, ctx->kvi);
                return 0;
        }

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

        if (!strcmp(var, "core.deltabasecachelimit")) {
                delta_base_cache_limit = git_config_ulong(var, value, ctx->kvi);
                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")) {
                FREE_AND_NULL(check_roundtrip_encoding);
                return git_config_string(&check_roundtrip_encoding, var, value);
        }

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

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

        if (!strcmp(var, "core.commentchar") ||
            !strcmp(var, "core.commentstring")) {
                if (!value)
                        return config_error_nonbool(var);
                else if (!strcasecmp(value, "auto"))
                        auto_comment_line_char = 1;
                else if (value[0]) {
                        if (strchr(value, '\n'))
                                return error(_("%s cannot contain newline"), var);
                        comment_line_str = value;
                        FREE_AND_NULL(comment_line_str_to_free);
                        auto_comment_line_char = 0;
                } else
                        return error(_("%s must have at least one character"), var);
                return 0;
        }

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

        if (!strcmp(var, "core.excludesfile")) {
                FREE_AND_NULL(excludes_file);
                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.fsync")) {
                if (!value)
                        return config_error_nonbool(var);
                fsync_components = parse_fsync_components(var, value);
                return 0;
        }

        if (!strcmp(var, "core.fsyncmethod")) {
                if (!value)
                        return config_error_nonbool(var);
                if (!strcmp(value, "fsync"))
                        fsync_method = FSYNC_METHOD_FSYNC;
                else if (!strcmp(value, "writeout-only"))
                        fsync_method = FSYNC_METHOD_WRITEOUT_ONLY;
                else if (!strcmp(value, "batch"))
                        fsync_method = FSYNC_METHOD_BATCH;
                else
                        warning(_("ignoring unknown core.fsyncMethod value '%s'"), value);

        }

        if (!strcmp(var, "core.fsyncobjectfiles")) {
                if (fsync_object_files < 0)
                        warning(_("core.fsyncObjectFiles is deprecated; use core.fsync instead"));
                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 (!value)
                        return config_error_nonbool(var);
                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.sparsecheckoutcone")) {
                core_sparse_checkout_cone = 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.maxtreedepth")) {
                max_allowed_tree_depth = git_config_int(var, value, ctx->kvi);
                return 0;
        }

        /* Add other config variables here and to Documentation/config.txt. */
        return platform_core_config(var, value, ctx, cb);
}

static int git_default_sparse_config(const char *var, const char *value)
{
        if (!strcmp(var, "sparse.expectfilesoutsideofpatterns")) {
                sparse_expect_files_outside_of_patterns = git_config_bool(var, value);
                return 0;
        }

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

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

        if (!strcmp(var, "i18n.logoutputencoding")) {
                FREE_AND_NULL(git_log_output_encoding);
                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 && !strcmp(value, "always")) {
                        git_branch_track = BRANCH_TRACK_ALWAYS;
                        return 0;
                } else if (value && !strcmp(value, "inherit")) {
                        git_branch_track = BRANCH_TRACK_INHERIT;
                        return 0;
                } else if (value && !strcmp(value, "simple")) {
                        git_branch_track = BRANCH_TRACK_SIMPLE;
                        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")) {
                FREE_AND_NULL(git_mailmap_file);
                return git_config_pathname(&git_mailmap_file, var, value);
        }

        if (!strcmp(var, "mailmap.blob")) {
                FREE_AND_NULL(git_mailmap_blob);
                return git_config_string(&git_mailmap_blob, var, value);
        }

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

static int git_default_attr_config(const char *var, const char *value)
{
        if (!strcmp(var, "attr.tree")) {
                FREE_AND_NULL(git_attr_tree);
                return git_config_string(&git_attr_tree, var, value);
        }

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

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

        if (starts_with(var, "user.") ||
            starts_with(var, "author.") ||
            starts_with(var, "committer."))
                return git_ident_config(var, value, ctx, cb);

        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, "attr."))
                return git_default_attr_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, ctx->kvi);
                return 0;
        }

        if (!strcmp(var, "pack.compression")) {
                int level = git_config_int(var, value, ctx->kvi);
                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;
        }

        if (starts_with(var, "sparse."))
                return git_default_sparse_config(var, value);

        /* 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, enum config_scope scope,
                          const struct config_options *opts)
{
        struct key_value_info kvi = KVI_INIT;
        int ret;

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

        ret = git_parse_source(top, fn, &kvi, data, opts);

        strbuf_release(&top->value);
        strbuf_release(&top->var);

        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, enum config_scope scope,
                               const struct config_options *opts)
{
        struct config_source top = CONFIG_SOURCE_INIT;
        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, scope, opts);
        funlockfile(f);
        return ret;
}

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

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

        if (!filename)
                BUG("filename cannot be NULL");
        f = fopen_or_warn(filename, "r");
        if (f) {
                ret = do_config_from_file(fn, CONFIG_ORIGIN_FILE, filename,
                                          filename, f, data, scope, 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,
                                                 CONFIG_SCOPE_UNKNOWN, 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, enum config_scope scope,
                        const struct config_options *opts)
{
        struct config_source top = CONFIG_SOURCE_INIT;

        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, scope, opts);
}

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

        buf = repo_read_object_file(repo, 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, scope, NULL);
        free(buf);

        return ret;
}

static int git_config_from_blob_ref(config_fn_t fn,
                                    struct repository *repo,
                                    const char *name,
                                    void *data,
                                    enum config_scope scope)
{
        struct object_id oid;

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

char *git_system_config(void)
{
        char *system_config = xstrdup_or_null(getenv("GIT_CONFIG_SYSTEM"));
        if (!system_config)
                system_config = system_path(ETC_GITCONFIG);
        normalize_path_copy(system_config, system_config);
        return system_config;
}

char *git_global_config(void)
{
        char *user_config, *xdg_config;

        git_global_config_paths(&user_config, &xdg_config);
        if (!user_config) {
                free(xdg_config);
                return NULL;
        }

        if (access_or_warn(user_config, R_OK, 0) && xdg_config &&
            !access_or_warn(xdg_config, R_OK, 0)) {
                free(user_config);
                return xdg_config;
        } else {
                free(xdg_config);
                return user_config;
        }
}

void git_global_config_paths(char **user_out, char **xdg_out)
{
        char *user_config = xstrdup_or_null(getenv("GIT_CONFIG_GLOBAL"));
        char *xdg_config = NULL;

        if (!user_config) {
                user_config = interpolate_path("~/.gitconfig", 0);
                xdg_config = xdg_config_home("config");
        }

        *user_out = user_config;
        *xdg_out = xdg_config;
}

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

static int do_git_config_sequence(const struct config_options *opts,
                                  const struct repository *repo,
                                  config_fn_t fn, void *data)
{
        int ret = 0;
        char *system_config = git_system_config();
        char *xdg_config = NULL;
        char *user_config = NULL;
        char *repo_config;
        char *worktree_config;

        /*
         * Ensure that either:
         * - the git_dir and commondir are both set, or
         * - the git_dir and commondir are both NULL
         */
        if (!opts->git_dir != !opts->commondir)
                BUG("only one of commondir and git_dir is non-NULL");

        if (opts->commondir) {
                repo_config = mkpathdup("%s/config", opts->commondir);
                worktree_config = mkpathdup("%s/config.worktree", opts->git_dir);
        } else {
                repo_config = NULL;
                worktree_config = NULL;
        }

        if (git_config_system() && system_config &&
            !access_or_die(system_config, R_OK,
                           opts->system_gently ? ACCESS_EACCES_OK : 0))
                ret += git_config_from_file_with_options(fn, system_config,
                                                         data, CONFIG_SCOPE_SYSTEM,
                                                         NULL);

        git_global_config_paths(&user_config, &xdg_config);

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

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

        if (!opts->ignore_repo && repo_config &&
            !access_or_die(repo_config, R_OK, 0))
                ret += git_config_from_file_with_options(fn, repo_config, data,
                                                         CONFIG_SCOPE_LOCAL, NULL);

        if (!opts->ignore_worktree && worktree_config &&
            repo && repo->repository_format_worktree_config &&
            !access_or_die(worktree_config, R_OK, 0)) {
                        ret += git_config_from_file_with_options(fn, worktree_config, data,
                                                                 CONFIG_SCOPE_WORKTREE,
                                                                 NULL);
        }

        if (!opts->ignore_cmdline && git_config_from_parameters(fn, data) < 0)
                die(_("unable to parse command-line config"));

        free(system_config);
        free(xdg_config);
        free(user_config);
        free(repo_config);
        free(worktree_config);
        return ret;
}

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

        if (opts->respect_includes) {
                inc.fn = fn;
                inc.data = data;
                inc.opts = opts;
                inc.repo = repo;
                inc.config_source = config_source;
                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) {
                ret = git_config_from_stdin(fn, data, config_source->scope);
        } else if (config_source && config_source->file) {
                ret = git_config_from_file_with_options(fn, config_source->file,
                                                        data, config_source->scope,
                                                        NULL);
        } else if (config_source && config_source->blob) {
                ret = git_config_from_blob_ref(fn, repo, config_source->blob,
                                               data, config_source->scope);
        } else {
                ret = do_git_config_sequence(opts, repo, fn, data);
        }

        if (inc.remote_urls) {
                string_list_clear(inc.remote_urls, 0);
                FREE_AND_NULL(inc.remote_urls);
        }
        return ret;
}

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

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

                ctx.kvi = values->items[value_index].util;
                if (fn(entry->key, values->items[value_index].string, &ctx, data) < 0)
                        git_die_config_linenr(entry->key,
                                              ctx.kvi->filename,
                                              ctx.kvi->linenr);
        }
}

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, NULL, &opts);

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

/*
 * Read config but only enumerate system and global settings.
 * Omit any repo-local, worktree-local, or command-line settings.
 */
void read_very_early_config(config_fn_t cb, void *data)
{
        struct config_options opts = { 0 };

        opts.respect_includes = 1;
        opts.ignore_repo = 1;
        opts.ignore_worktree = 1;
        opts.ignore_cmdline = 1;
        opts.system_gently = 1;

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

RESULT_MUST_BE_USED
static int configset_find_element(struct config_set *set, const char *key,
                                  struct config_set_element **dest)
{
        struct config_set_element k;
        struct config_set_element *found_entry;
        char *normalized_key;
        int ret;

        /*
         * `key` may come from the user, so normalize it before using it
         * for querying entries from the hashmap.
         */
        ret = git_config_parse_key(key, &normalized_key, NULL);
        if (ret)
                return ret;

        hashmap_entry_init(&k.ent, strhash(normalized_key));
        k.key = normalized_key;
        found_entry = hashmap_get_entry(&set->config_hash, &k, ent, NULL);
        free(normalized_key);
        *dest = found_entry;
        return 0;
}

static int configset_add_value(const struct key_value_info *kvi_p,
                               struct config_set *set, 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));
        int ret;

        ret = configset_find_element(set, key, &e);
        if (ret)
                return ret;
        /*
         * 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->ent, strhash(key));
                e->key = xstrdup(key);
                string_list_init_dup(&e->value_list);
                hashmap_add(&set->config_hash, &e->ent);
        }
        si = string_list_append_nodup(&e->value_list, xstrdup_or_null(value));

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

        *kv_info = *kvi_p;
        si->util = kv_info;

        return 0;
}

static int config_set_element_cmp(const void *cmp_data UNUSED,
                                  const struct hashmap_entry *eptr,
                                  const struct hashmap_entry *entry_or_key,
                                  const void *keydata UNUSED)
{
        const struct config_set_element *e1, *e2;

        e1 = container_of(eptr, const struct config_set_element, ent);
        e2 = container_of(entry_or_key, const struct config_set_element, ent);

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

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

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

        hashmap_for_each_entry(&set->config_hash, &iter, entry,
                                ent /* member name */) {
                free(entry->key);
                string_list_clear(&entry->value_list, 1);
        }
        hashmap_clear_and_free(&set->config_hash, struct config_set_element, ent);
        set->hash_initialized = 0;
        free(set->list.items);
        set->list.nr = 0;
        set->list.alloc = 0;
        set->list.items = NULL;
}

static int config_set_callback(const char *key, const char *value,
                               const struct config_context *ctx,
                               void *cb)
{
        struct config_set *set = cb;
        configset_add_value(ctx->kvi, set, key, value);
        return 0;
}

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

int git_configset_get_value(struct config_set *set, const char *key,
                            const char **value, struct key_value_info *kvi)
{
        const struct string_list *values = NULL;
        int ret;
        struct string_list_item item;
        /*
         * 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.
         */
        if ((ret = git_configset_get_value_multi(set, key, &values)))
                return ret;

        assert(values->nr > 0);
        item = values->items[values->nr - 1];
        *value = item.string;
        if (kvi)
                *kvi = *((struct key_value_info *)item.util);
        return 0;
}

int git_configset_get_value_multi(struct config_set *set, const char *key,
                                  const struct string_list **dest)
{
        struct config_set_element *e;
        int ret;

        if ((ret = configset_find_element(set, key, &e)))
                return ret;
        else if (!e)
                return 1;
        *dest = &e->value_list;

        return 0;
}

static int check_multi_string(struct string_list_item *item, void *util)
{
        return item->string ? 0 : config_error_nonbool(util);
}

int git_configset_get_string_multi(struct config_set *cs, const char *key,
                                   const struct string_list **dest)
{
        int ret;

        if ((ret = git_configset_get_value_multi(cs, key, dest)))
                return ret;
        if ((ret = for_each_string_list((struct string_list *)*dest,
                                        check_multi_string, (void *)key)))
                return ret;

        return 0;
}

int git_configset_get(struct config_set *set, const char *key)
{
        struct config_set_element *e;
        int ret;

        if ((ret = configset_find_element(set, key, &e)))
                return ret;
        else if (!e)
                return 1;
        return 0;
}

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

static int git_configset_get_string_tmp(struct config_set *set, const char *key,
                                        const char **dest)
{
        const char *value;
        if (!git_configset_get_value(set, key, &value, NULL)) {
                if (!value)
                        return config_error_nonbool(key);
                *dest = value;
                return 0;
        } else {
                return 1;
        }
}

int git_configset_get_int(struct config_set *set, const char *key, int *dest)
{
        const char *value;
        struct key_value_info kvi;

        if (!git_configset_get_value(set, key, &value, &kvi)) {
                *dest = git_config_int(key, value, &kvi);
                return 0;
        } else
                return 1;
}

int git_configset_get_ulong(struct config_set *set, const char *key, unsigned long *dest)
{
        const char *value;
        struct key_value_info kvi;

        if (!git_configset_get_value(set, key, &value, &kvi)) {
                *dest = git_config_ulong(key, value, &kvi);
                return 0;
        } else
                return 1;
}

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

int git_configset_get_bool_or_int(struct config_set *set, const char *key,
                                int *is_bool, int *dest)
{
        const char *value;
        struct key_value_info kvi;

        if (!git_configset_get_value(set, key, &value, &kvi)) {
                *dest = git_config_bool_or_int(key, value, &kvi, is_bool);
                return 0;
        } else
                return 1;
}

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

int git_configset_get_pathname(struct config_set *set, const char *key, char **dest)
{
        const char *value;
        if (!git_configset_get_value(set, key, &value, NULL))
                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 = { 0 };

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

        if (!repo->config)
                CALLOC_ARRAY(repo->config, 1);
        else
                git_configset_clear(repo->config);

        git_configset_init(repo->config);
        if (config_with_options(config_set_callback, repo->config, NULL,
                                repo, &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);
}

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

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, NULL);
}

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

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

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

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

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

/* Read values into protected_config. */
static void read_protected_config(void)
{
        struct config_options opts = {
                .respect_includes = 1,
                .ignore_repo = 1,
                .ignore_worktree = 1,
                .system_gently = 1,
        };

        git_configset_init(&protected_config);
        config_with_options(config_set_callback, &protected_config, NULL,
                            NULL, &opts);
}

void git_protected_config(config_fn_t fn, void *data)
{
        if (!protected_config.hash_initialized)
                read_protected_config();
        configset_iter(&protected_config, fn, data);
}

int repo_config_get_expiry(struct repository *r, const char *key, char **output)
{
        int ret = repo_config_get_string(r, key, output);

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

int repo_config_get_expiry_in_days(struct repository *r, const char *key,
                                   timestamp_t *expiry, timestamp_t now)
{
        const char *expiry_string;
        intmax_t days;
        timestamp_t when;

        if (repo_config_get_string_tmp(r, 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 repo_config_get_split_index(struct repository *r)
{
        int val;

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

        return -1; /* default value */
}

int repo_config_get_max_percent_split_change(struct repository *r)
{
        int val = -1;

        if (!repo_config_get_int(r, "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 repo_config_get_index_threads(struct repository *r, int *dest)
{
        int is_bool, val;

        val = git_env_ulong("GIT_TEST_INDEX_THREADS", 0);
        if (val) {
                *dest = val;
                return 0;
        }

        if (!repo_config_get_bool_or_int(r, "index.threads", &is_bool, &val)) {
                if (is_bool)
                        *dest = val ? 0 : 1;
                else
                        *dest = val;
                return 0;
        }

        return 1;
}

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);
}

void git_die_config(struct repository *r, const char *key, const char *err, ...)
{
        const struct string_list *values;
        struct key_value_info *kv_info;
        report_fn error_fn = get_error_routine();

        if (err) {
                va_list params;
                va_start(params, err);
                error_fn(err, params);
                va_end(params);
        }
        if (repo_config_get_value_multi(r, key, &values))
                BUG("for key '%s' we must have a value to report on", 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 {
        size_t baselen;
        char *key;
        int do_not_match;
        const char *fixed_value;
        regex_t *value_pattern;
        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;
};
#define CONFIG_STORE_INIT { 0 }

static void config_store_data_clear(struct config_store_data *store)
{
        free(store->key);
        if (store->value_pattern != NULL &&
            store->value_pattern != CONFIG_REGEX_NONE) {
                regfree(store->value_pattern);
                free(store->value_pattern);
        }
        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->fixed_value && value)
                return !strcmp(store->fixed_value, value);
        if (!store->value_pattern)
                return 1; /* always matches */
        if (store->value_pattern == CONFIG_REGEX_NONE)
                return 0; /* never matches */

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

static int store_aux_event(enum config_event_t type, size_t begin, size_t end,
                           struct config_source *cs, 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) {
                int (*cmpfn)(const char *, const char *, size_t);

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

                if (cs->subsection_case_sensitive)
                        cmpfn = strncasecmp;
                else
                        cmpfn = strncmp;

                /* Is this the section we were looking for? */
                store->is_keys_section =
                        store->parsed[store->parsed_nr].is_keys_section =
                        cs->var.len - 1 == store->baselen &&
                        !cmpfn(cs->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,
                     const struct config_context *ctx UNUSED, 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;
        size_t 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_addch(&sb, '[');
                strbuf_add(&sb, key, store->baselen);
                strbuf_addstr(&sb, "]\n");
        }

        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 char *comment,
                          const struct config_store_data *store)
{
        int i;
        ssize_t ret;
        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", 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;
                }

        if (comment)
                strbuf_addf(&sb, "%s%s\n", quote, comment);
        else
                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,
                                 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 the 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 repo_config_set_in_file_gently(struct repository *r, const char *config_filename,
                                   const char *key, const char *comment, const char *value)
{
        return repo_config_set_multivar_in_file_gently(r, config_filename, key, value, NULL, comment, 0);
}

void repo_config_set_in_file(struct repository *r, const char *config_filename,
                             const char *key, const char *value)
{
        repo_config_set_multivar_in_file(r, config_filename, key, value, NULL, 0);
}

int repo_config_set_gently(struct repository *r, const char *key, const char *value)
{
        return repo_config_set_multivar_gently(r, key, value, NULL, 0);
}

int repo_config_set_worktree_gently(struct repository *r,
                                    const char *key, const char *value)
{
        /* Only use worktree-specific config if it is already enabled. */
        if (r->repository_format_worktree_config) {
                char *file = repo_git_path(r, "config.worktree");
                int ret = repo_config_set_multivar_in_file_gently(
                                        r, file, key, value, NULL, NULL, 0);
                free(file);
                return ret;
        }
        return repo_config_set_multivar_gently(r, key, value, NULL, 0);
}

void repo_config_set(struct repository *r, const char *key, const char *value)
{
        repo_config_set_multivar(r, key, value, NULL, 0);

        trace2_cmd_set_config(key, value);
}

char *git_config_prepare_comment_string(const char *comment)
{
        size_t leading_blanks;
        char *prepared;

        if (!comment)
                return NULL;

        if (strchr(comment, '\n'))
                die(_("no multi-line comment allowed: '%s'"), comment);

        /*
         * If it begins with one or more leading whitespace characters
         * followed by '#", the comment string is used as-is.
         *
         * If it begins with '#', a SP is inserted between the comment
         * and the value the comment is about.
         *
         * Otherwise, the value is followed by a SP followed by '#'
         * followed by SP and then the comment string comes.
         */

        leading_blanks = strspn(comment, " \t");
        if (leading_blanks && comment[leading_blanks] == '#')
                prepared = xstrdup(comment); /* use it as-is */
        else if (comment[0] == '#')
                prepared = xstrfmt(" %s", comment);
        else
                prepared = xstrfmt(" # %s", comment);

        return prepared;
}

static void validate_comment_string(const char *comment)
{
        size_t leading_blanks;

        if (!comment)
                return;
        /*
         * The front-end must have massaged the comment string
         * properly before calling us.
         */
        if (strchr(comment, '\n'))
                BUG("multi-line comments are not permitted: '%s'", comment);

        leading_blanks = strspn(comment, " \t");
        if (!leading_blanks || comment[leading_blanks] != '#')
                BUG("comment must begin with one or more SP followed by '#': '%s'",
                    comment);
}

/*
 * If value==NULL, unset in (remove from) config,
 * if value_pattern!=NULL, disregard key/value pairs where value does not match.
 * if value_pattern==CONFIG_REGEX_NONE, do not match any existing values
 *     (only add a new one)
 * if flags contains the CONFIG_FLAGS_MULTI_REPLACE flag, all matching
 *     key/values are removed before a single new pair is written. If the
 *     flag is not present, then replace only the first match.
 *
 * 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 repo_config_set_multivar_in_file_gently(struct repository *r,
                                            const char *config_filename,
                                            const char *key, const char *value,
                                            const char *value_pattern,
                                            const char *comment,
                                            unsigned flags)
{
        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 = CONFIG_STORE_INIT;

        validate_comment_string(comment);

        /* 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 = (flags & CONFIG_FLAGS_MULTI_REPLACE) != 0;

        if (!config_filename)
                config_filename = filename_buf = repo_git_path(r, "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) {
                        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, comment, &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_pattern)
                        store.value_pattern = NULL;
                else if (value_pattern == CONFIG_REGEX_NONE)
                        store.value_pattern = CONFIG_REGEX_NONE;
                else if (flags & CONFIG_FLAGS_FIXED_VALUE)
                        store.fixed_value = value_pattern;
                else {
                        if (value_pattern[0] == '!') {
                                store.do_not_match = 1;
                                value_pattern++;
                        } else
                                store.do_not_match = 0;

                        store.value_pattern = (regex_t*)xmalloc(sizeof(regex_t));
                        if (regcomp(store.value_pattern, value_pattern,
                                        REG_EXTENDED)) {
                                error(_("invalid pattern: %s"), value_pattern);
                                FREE_AND_NULL(store.value_pattern);
                                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, CONFIG_SCOPE_UNKNOWN,
                                                      &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 && !store.multi_replace)) {
                        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'%s"),
                                        config_filename, mmap_os_err());
                        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,
                                                             &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) {
                        if (!store.section_seen) {
                                if (write_section(fd, key, &store) < 0)
                                        goto write_err_out;
                        }
                        if (write_pair(fd, key, value, comment, &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 */
        repo_config_clear(r);

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 repo_config_set_multivar_in_file(struct repository *r,
                                      const char *config_filename,
                                      const char *key, const char *value,
                                      const char *value_pattern, unsigned flags)
{
        if (!repo_config_set_multivar_in_file_gently(r, config_filename, key, value,
                                                     value_pattern, NULL, flags))
                return;
        if (value)
                die(_("could not set '%s' to '%s'"), key, value);
        else
                die(_("could not unset '%s'"), key);
}

int repo_config_set_multivar_gently(struct repository *r, const char *key,
                                    const char *value,
                                    const char *value_pattern, unsigned flags)
{
        char *file = repo_git_path(r, "config");
        int res = repo_config_set_multivar_in_file_gently(r, file,
                                                          key, value,
                                                          value_pattern,
                                                          NULL, flags);
        free(file);
        return res;
}

void repo_config_set_multivar(struct repository *r,
                              const char *key, const char *value,
                              const char *value_pattern, unsigned flags)
{
        char *file = repo_git_path(r, "config");
        repo_config_set_multivar_in_file(r, file, key, value,
                                         value_pattern, flags);
        free(file);
}

static size_t section_name_match (const char *buf, const char *name)
{
        size_t i = 0, j = 0;
        int 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;
}

#define GIT_CONFIG_MAX_LINE_LEN (512 * 1024)

/* if new_name == NULL, the section is removed instead */
static int repo_config_copy_or_rename_section_in_file(
        struct repository *r,
        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;
        struct strbuf buf = STRBUF_INIT;
        FILE *config_file = NULL;
        struct stat st;
        struct strbuf copystr = STRBUF_INIT;
        struct config_store_data store;
        uint32_t line_nr = 0;

        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 = repo_git_path(r, "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 (!strbuf_getwholeline(&buf, config_file, '\n')) {
                size_t i, length;
                int is_section = 0;
                char *output = buf.buf;

                line_nr++;

                if (buf.len >= GIT_CONFIG_MAX_LINE_LEN) {
                        ret = error(_("refusing to work with overly long line "
                                      "in '%s' on line %"PRIuMAX),
                                    config_filename, (uintmax_t)line_nr);
                        goto out;
                }

                for (i = 0; buf.buf[i] && isspace(buf.buf[i]); i++)
                        ; /* do nothing */
                if (buf.buf[i] == '[') {
                        /* it's a section */
                        size_t 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.buf[i], old_name);
                        if (offset > 0) {
                                ret++;
                                if (!new_name) {
                                        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 {
                                        strbuf_release(&copystr);
                                        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);
        strbuf_release(&buf);
        strbuf_release(&copystr);
        return ret;
}

int repo_config_rename_section_in_file(struct repository *r, const char *config_filename,
                                       const char *old_name, const char *new_name)
{
        return repo_config_copy_or_rename_section_in_file(r, config_filename,
                                         old_name, new_name, 0);
}

int repo_config_rename_section(struct repository *r, const char *old_name, const char *new_name)
{
        return repo_config_rename_section_in_file(r, NULL, old_name, new_name);
}

int repo_config_copy_section_in_file(struct repository *r, const char *config_filename,
                                     const char *old_name, const char *new_name)
{
        return repo_config_copy_or_rename_section_in_file(r, config_filename,
                                         old_name, new_name, 1);
}

int repo_config_copy_section(struct repository *r, const char *old_name, const char *new_name)
{
        return repo_config_copy_section_in_file(r, 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, size_t *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 *config_origin_type_name(enum config_origin_type type)
{
        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 *config_scope_name(enum config_scope scope)
{
        switch (scope) {
        case CONFIG_SCOPE_SYSTEM:
                return "system";
        case CONFIG_SCOPE_GLOBAL:
                return "global";
        case CONFIG_SCOPE_LOCAL:
                return "local";
        case CONFIG_SCOPE_WORKTREE:
                return "worktree";
        case CONFIG_SCOPE_COMMAND:
                return "command";
        case CONFIG_SCOPE_SUBMODULE:
                return "submodule";
        default:
                return "unknown";
        }
}

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;
}