git/config.c

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

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

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

static int 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;
	struct git_config_source *config_source;

	/*
	 * 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, 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 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 (!cf || !cf->path) {
			ret = error(_("relative config includes must come from files"));
			goto cleanup;
		}

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

	if (!access_or_die(path, R_OK, 0)) {
		if (++inc->depth > MAX_INCLUDE_DEPTH)
			die(_(include_depth_advice), MAX_INCLUDE_DEPTH, path,
			    !cf ? "<unknown>" :
			    cf->name ? cf->name :
			    "the command line");
		ret = git_config_from_file(git_config_include, path, inc);
		inc->depth--;
	}
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(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 (!cf || !cf->path)
			return error(_("relative config include "
				       "conditionals must come from files"));

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

	add_trailing_starstar_for_dir(pat);

	strbuf_release(&path);
	return prefix;
}

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

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

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

again:
	if (prefix < 0)
		goto done;

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

	ret = !wildmatch(pattern.buf + prefix, text.buf + prefix,
			 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(const char *cond, size_t cond_len)
{
	int flags;
	int ret;
	struct strbuf pattern = STRBUF_INIT;
	const char *refname = !the_repository->gitdir ?
		NULL : resolve_ref_unsafe("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, 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;

	struct config_source *store_cf = cf;
	struct key_value_info *store_kvi = current_config_kvi;
	enum config_scope store_scope = current_parsing_scope;

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

	cf = NULL;
	current_config_kvi = NULL;
	current_parsing_scope = 0;

	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, &opts);

	cf = store_cf;
	current_config_kvi = store_kvi;
	current_parsing_scope = store_scope;
}

static int forbid_remote_url(const char *var, const char *value, void *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"))
		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(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(opts, cond, cond_len, 0);
	else if (skip_prefix_mem(cond, cond_len, "gitdir/i:", &cond, &cond_len))
		return include_by_gitdir(opts, cond, cond_len, 1);
	else if (skip_prefix_mem(cond, cond_len, "onbranch:", &cond, &cond_len))
		return include_by_branch(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, 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, inc->data);
	if (ret < 0)
		return ret;

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

	if (!parse_config_key(var, "includeif", &cond, &cond_len, &key) &&
	    cond && include_condition_is_true(inc, 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(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,
			  config_fn_t fn, void *data)
{
	char *canonical_name;
	int ret;

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

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

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

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

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

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

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

static int parse_config_env_list(char *env, 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, 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 config_source source;

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

	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, 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, fn, data) < 0) {
			ret = -1;
			goto out;
		}
	}

out:
	strbuf_release(&envvar);
	strvec_clear(&to_free);
	free(envw);
	cf = source.prev;
	return ret;
}

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

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

	if (c != EOF && ++cf->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.
		 */
		cf->eof = 1;
		return 0;
	}

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

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

	strbuf_reset(&cf->value);
	for (;;) {
		int c = get_next_char();
		if (c == '\n') {
			if (quote) {
				cf->linenr--;
				return NULL;
			}
			return cf->value.buf;
		}
		if (comment)
			continue;
		if (isspace(c) && !quote) {
			if (cf->value.len)
				space++;
			continue;
		}
		if (!quote) {
			if (c == ';' || c == '#') {
				comment = 1;
				continue;
			}
		}
		for (; space; space--)
			strbuf_addch(&cf->value, ' ');
		if (c == '\\') {
			c = get_next_char();
			switch (c) {
			case '\n':
				continue;
			case 't':
				c = '\t';
				break;
			case 'b':
				c = '\b';
				break;
			case 'n':
				c = '\n';
				break;
			/* Some characters escape as themselves */
			case '\\': case '"':
				break;
			/* Reject unknown escape sequences */
			default:
				return NULL;
			}
			strbuf_addch(&cf->value, c);
			continue;
		}
		if (c == '"') {
			quote = 1-quote;
			continue;
		}
		strbuf_addch(&cf->value, c);
	}
}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	return 0;
}

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

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

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

	for (;;) {
		int c;

		c = get_next_char();
		if (bomptr && *bomptr) {
			/* We are at the file beginning; skip UTF8-encoded BOM
			 * if present. Sane editors won't put this in on their
			 * own, but e.g. Windows Notepad will do it happily. */
			if (c == (*bomptr & 0377)) {
				bomptr++;
				continue;
			} else {
				/* Do not tolerate partial BOM. */
				if (bomptr != utf8_bom)
					break;
				/* No BOM at file beginning. Cool. */
				bomptr = NULL;
			}
		}
		if (c == '\n') {
			if (cf->eof) {
				if (do_event(CONFIG_EVENT_EOF, &event_data) < 0)
					return -1;
				return 0;
			}
			if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
				return -1;
			comment = 0;
			continue;
		}
		if (comment)
			continue;
		if (isspace(c)) {
			if (do_event(CONFIG_EVENT_WHITESPACE, &event_data) < 0)
					return -1;
			continue;
		}
		if (c == '#' || c == ';') {
			if (do_event(CONFIG_EVENT_COMMENT, &event_data) < 0)
					return -1;
			comment = 1;
			continue;
		}
		if (c == '[') {
			if (do_event(CONFIG_EVENT_SECTION, &event_data) < 0)
					return -1;

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

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

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

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

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

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

	free(error_msg);
	return error_return;
}

static uintmax_t get_unit_factor(const char *end)
{
	if (!*end)
		return 1;
	else if (!strcasecmp(end, "k"))
		return 1024;
	else if (!strcasecmp(end, "m"))
		return 1024 * 1024;
	else if (!strcasecmp(end, "g"))
		return 1024 * 1024 * 1024;
	return 0;
}

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

		errno = 0;
		val = strtoimax(value, &end, 0);
		if (errno == ERANGE)
			return 0;
		factor = get_unit_factor(end);
		if (!factor) {
			errno = EINVAL;
			return 0;
		}
		uval = val < 0 ? -val : val;
		if (unsigned_mult_overflows(factor, uval) ||
		    factor * uval > max) {
			errno = ERANGE;
			return 0;
		}
		val *= factor;
		*ret = val;
		return 1;
	}
	errno = EINVAL;
	return 0;
}

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

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

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

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

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

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

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

	if (!value)
		value = "";

	if (!(cf && cf->name))
		die(_(bad_numeric), value, name, _(error_type));

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

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

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

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

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

static int git_parse_maybe_bool_text(const char *value)
{
	if (!value)
		return 1;
	if (!*value)
		return 0;
	if (!strcasecmp(value, "true")
	    || !strcasecmp(value, "yes")
	    || !strcasecmp(value, "on"))
		return 1;
	if (!strcasecmp(value, "false")
	    || !strcasecmp(value, "no")
	    || !strcasecmp(value, "off"))
		return 0;
	return -1;
}

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

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

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

int git_config_pathname(const char **dest, const char *var, const char *value)
{
	if (!value)
		return config_error_nonbool(var);
	*dest = 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, 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 (!strcasecmp(value, "default"))
			check_stat = 1;
		else if (!strcasecmp(value, "minimal"))
			check_stat = 0;
	}

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

	/* Add other config variables here and to Documentation/config.txt. */
	return platform_core_config(var, value, 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"))
		return git_config_string(&git_commit_encoding, var, value);

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

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

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

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

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

	if (starts_with(var, "user.") ||
	    starts_with(var, "author.") ||
	    starts_with(var, "committer."))
		return git_ident_config(var, value, 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, "advice.") || starts_with(var, "color.advice"))
		return git_default_advice_config(var, value);

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

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

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

	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,
			  const struct config_options *opts)
{
	int ret;

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

	ret = git_parse_source(fn, data, opts);

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

	return ret;
}

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

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

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

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

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

	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, opts);
		fclose(f);
	}
	return ret;
}

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

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

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

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

int git_config_from_blob_oid(config_fn_t fn,
			      const char *name,
			      struct repository *repo,
			      const struct object_id *oid,
			      void *data)
{
	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, NULL);
	free(buf);

	return ret;
}

static int git_config_from_blob_ref(config_fn_t fn,
				    struct repository *repo,
				    const char *name,
				    void *data)
{
	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);
}

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;
}

void git_global_config(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;
}

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

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

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

static int do_git_config_sequence(const struct config_options *opts,
				  config_fn_t fn, void *data)
{
	int ret = 0;
	char *system_config = git_system_config();
	char *xdg_config = NULL;
	char *user_config = NULL;
	char *repo_config;
	enum config_scope prev_parsing_scope = current_parsing_scope;

	if (opts->commondir)
		repo_config = mkpathdup("%s/config", opts->commondir);
	else if (opts->git_dir)
		BUG("git_dir without commondir");
	else
		repo_config = NULL;

	current_parsing_scope = CONFIG_SCOPE_SYSTEM;
	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(fn, system_config, data);

	current_parsing_scope = CONFIG_SCOPE_GLOBAL;
	git_global_config(&user_config, &xdg_config);

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

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

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

	current_parsing_scope = CONFIG_SCOPE_WORKTREE;
	if (!opts->ignore_worktree && repository_format_worktree_config) {
		char *path = git_pathdup("config.worktree");
		if (!access_or_die(path, R_OK, 0))
			ret += git_config_from_file(fn, path, data);
		free(path);
	}

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

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

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

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

	if (config_source)
		current_parsing_scope = config_source->scope;

	/*
	 * 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);
	} else if (config_source && config_source->file) {
		ret = git_config_from_file(fn, config_source->file, data);
	} else if (config_source && config_source->blob) {
		struct repository *repo = config_source->repo ?
			config_source->repo : the_repository;
		ret = git_config_from_blob_ref(fn, repo, config_source->blob,
						data);
	} else {
		ret = do_git_config_sequence(opts, 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 *cs, config_fn_t fn, void *data)
{
	int i, value_index;
	struct string_list *values;
	struct config_set_element *entry;
	struct configset_list *list = &cs->list;

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

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

		if (fn(entry->key, values->items[value_index].string, data) < 0)