#include <stdio.h>
#include <ctype.h>
#include <string.h>
#include <stdbool.h>
#include <errno.h>
#include <unistd.h>
#include <arpa/inet.h>
#include <inttypes.h>
#include <sys/types.h>
#include <dirent.h>

#include "utils.h"
#include "config-parser.h"
#include "server-config-options.h"
#include "config.h"

static void handle_dns_reply(struct server_config *scfg, enum scfg_keys type,
			     struct saddr *saddr)
{
	switch (type) {
	case SCFG_KEY_LOCAL:
		list_add(&saddr->list, &scfg->locals);
		break;
	case SCFG_KEY_REMOTE:
		list_add(&saddr->list, &scfg->remotes);
		break;
	case SCFG_KEY_RCON:
		list_add(&saddr->list, &scfg->rcons);
		break;
	default:
		error("invalid DNS reply type");
		break;
	}
}

static void scfg_dns_cb(struct dns_async *dns, enum scfg_keys type)
{
	struct server_config *scfg;
	struct sockaddr_in *in4;
	struct sockaddr_in6 *in6;
	struct saddr *saddr;
	struct addrinfo *results = NULL, *ai;
	int r;

	assert_return(dns);

	scfg = dns->priv;
	debug(DBG_DNS, "called, dns: %p, name: %s", dns, dns->name);

	r = gai_error(&dns->gcb);
	if (r == EAI_INPROGRESS) {
		/* This shouldn't happen, assume we'll get called again */
		error("called with request in progress");
		return;
	} else if (r == EAI_CANCELED) {
		/* The server must be in the process of going away */
		goto out;
	} else if (r < 0) {
		error("DNS lookup of %s:%s failed: %s", dns->name, dns->port,
		      gai_strerror(r));
		goto out;
	}

	results = dns->gcb.ar_result;

	for (ai = results; ai; ai = ai->ai_next) {
		saddr = zmalloc(sizeof(*saddr));
		if (!saddr) {
			error("DNS lookup of %s:%s failed: %m", dns->name,
			      dns->port);
			goto out;
		}

		switch (ai->ai_family) {
		case AF_INET:
			in4 = (struct sockaddr_in *)ai->ai_addr;
			saddr_set_ipv4(saddr, in4->sin_addr.s_addr,
				       in4->sin_port);
			break;

		case AF_INET6:
			in6 = (struct sockaddr_in6 *)ai->ai_addr;
			saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
			break;

		default:
			error("getaddrinfo(%s:%s): unknown address family (%i)",
			      dns->name, dns->port, ai->ai_family);
			xfree(saddr);
			continue;
		}

		handle_dns_reply(scfg, type, saddr);
	}

out:
	freeaddrinfo(results);
	list_del(&dns->list);
	if (dns->notification_cb)
		dns->notification_cb(scfg, true);
	xfree(dns);
}

static void scfg_dns_local_cb(struct dns_async *dns)
{
	scfg_dns_cb(dns, SCFG_KEY_LOCAL);
}

static void scfg_dns_remote_cb(struct dns_async *dns)
{
	scfg_dns_cb(dns, SCFG_KEY_REMOTE);
}

static void scfg_dns_rcon_cb(struct dns_async *dns)
{
	scfg_dns_cb(dns, SCFG_KEY_RCON);
}

static bool handle_dns(struct server_config *scfg, enum scfg_keys type,
		       struct cfg_value *value,
		       notification_cb_t notification_cb)
{
	struct saddr *saddr, *tmp;
	struct dns_async *dns;

	assert_return(scfg && type && value, false);

	switch (value->type) {
	case CFG_VAL_TYPE_ADDRS:
		debug(DBG_DNS, "%i: got immediate addrs", type);

		list_for_each_entry_safe(saddr, tmp, &value->saddrs, list) {
			list_del(&saddr->list);
			handle_dns_reply(scfg, type, saddr);
		}
		return true;

	case CFG_VAL_TYPE_ASYNC_ADDRS:
		debug(DBG_DNS, "doing async lookup of DNS record: %p",
		      value->dns_async);

		dns = value->dns_async;
		switch (type) {
		case SCFG_KEY_LOCAL:
			dns->cb = scfg_dns_local_cb;
			break;
		case SCFG_KEY_REMOTE:
			dns->cb = scfg_dns_remote_cb;
			break;
		case SCFG_KEY_RCON:
			dns->cb = scfg_dns_rcon_cb;
			break;
		default:
			error("invalid DNS lookup type");
			return false;
		}

		if (!!notification_cb) {
			error("async DNS lookup received but not requested");
			xfree(dns);
			return false;
		}

		dns->priv = scfg;
		dns->notification_cb = notification_cb;
		list_add(&dns->list, &scfg->dnslookups);
		dns->notification_cb(scfg, false);
		return true;

	default:
		return false;
	}
}

static inline char tohex(uint8_t val)
{
	static const char hex[] = "0123456789abcdef";

	return hex[val & 0x0f];
}

/*
 * Creates an escaped D-Bus object path for a given systemd service
 *
 * Escaping rules are documented here:
 * https://dbus.freedesktop.org/doc/dbus-specification.html
 *
 * Essentially, everyting but a-z, A-Z, 0-9 is replaced by _xx where xx is
 * the hexadecimal value of the character.
 *
 * Example: minecraft@world1.service -> minecraft_40world1_2eservice
 */
static char *systemd_object_path(const char *service)
{
	char *r;
	char *d;
	const char *s;

	assert_return(service && !empty_str(service), NULL);

	r = zmalloc(STRLEN(SYSTEMD_DBUS_PATH_PREFIX) + strlen(service) * 3 + 1);
	if (!r)
		return NULL;

	memcpy(r, SYSTEMD_DBUS_PATH_PREFIX, STRLEN(SYSTEMD_DBUS_PATH_PREFIX));
	d = r + STRLEN(SYSTEMD_DBUS_PATH_PREFIX);

	for (s = service; *s; s++) {
		if ((*s >= 'a' && *s <= 'z') || (*s >= 'A' && *s <= 'Z') ||
		    (*s >= '0' && *s <= '9')) {
			*(d++) = *s;
			continue;
		}

		*(d++) = '_';
		*(d++) = tohex(*s >> 4);
		*(d++) = tohex(*s);
	}

	*d = '\0';
	return r;
}

/* FIXME: Add a strict argument */
bool scfg_validate(struct server_config *scfg)
{
	struct saddr *saddr;
	uint16_t port;

	if (!scfg) {
		error("invalid arguments");
		return false;
	}

	if (!scfg->filename) {
		error("filename not set");
		return false;
	}

	if (!list_empty(&scfg->dnslookups)) {
		error("%s: pending DNS requests",
		      scfg->filename);
		return false;
	}

	if (scfg->stop_method == SERVER_STOP_METHOD_RCON &&
	    list_empty(&scfg->rcons)) {
		error("%s: rcon stop method missing rcon address",
		      scfg->filename);
		return false;
	}

	if (scfg->stop_method == SERVER_STOP_METHOD_RCON &&
	    !scfg->rcon_password) {
		error("%s: rcon stop method missing rcon password",
		      scfg->filename);
		return false;
	}

	if ((scfg->start_method == SERVER_START_METHOD_SYSTEMD ||
	     scfg->stop_method == SERVER_STOP_METHOD_SYSTEMD)) {
		if (!scfg->systemd_service || !scfg->systemd_obj) {
			error("%s: systemd start/stop method missing "
			      "systemd service", scfg->filename);
			return false;
		} else {
			if (scfg->systemd_service || scfg->systemd_obj) {
				error("%s: systemd service set but not used",
				      scfg->filename);
				return false;
			}
		}
	}

	if (scfg->idle_timeout > 0 &&
	    scfg->stop_method == SERVER_STOP_METHOD_UNDEFINED) {
		error("%s: idle_timeout set but missing stop method",
		      scfg->filename);
		return false;
	}

	switch (scfg->type) {
	case SERVER_TYPE_ANNOUNCE:
		if (scfg->announce_port == 0) {
			error("%s: missing announce port", scfg->filename);
			return false;
		}

		if (scfg->start_method != SERVER_START_METHOD_UNDEFINED) {
			error("%s: can't set start_method for announce server",
			      scfg->filename);
			return false;
		}

		if (scfg->start_exec) {
			error("%s: can't set start_exec for announce server",
			      scfg->filename);
			return false;
		}

		if (!list_empty(&scfg->locals)) {
			error("%s: can't set local addresses for announce server",
			      scfg->filename);
			return false;
		}

		if (!list_empty(&scfg->remotes)) {
			error("%s: can't set remote addresses for announce server",
			      scfg->filename);
			return false;
		}

		break;

	case SERVER_TYPE_PROXY:
		if (scfg->announce_port == 0) {
			error("%s: can't set announce port for proxy server",
			      scfg->filename);
			return false;
		}

		if (list_empty(&scfg->locals)) {
			error("%s: missing local addresses for proxy server",
			      scfg->filename);
			return false;
		}

		if (list_empty(&scfg->remotes)) {
			error("%s: missing remote addresses for proxy server",
			      scfg->filename);
			return false;
		}

		list_for_each_entry(saddr, &scfg->locals, list) {
			port = saddr_port(saddr);

			if (port == 0) {
				error("%s: invalid local port", scfg->filename);
				return false;
			}

			if (scfg->announce_port == 0)
				scfg->announce_port = port;
			else if (scfg->announce_port != port) {
				error("%s: multiple local ports", scfg->filename);
				return false;
			}
		}

		if (scfg->announce_port == 0) {
			error("%s: can't determine which port to announce",
			      scfg->filename);
			return false;
		}

		break;

	default:
		error("%s: can't determine server type", scfg->filename);
		return false;
	}

	return true;
}

#define INVALID(fmt, ...) \
do { \
	verbose("%s: " fmt, scfg->filename __VA_OPT__(,) __VA_ARGS__); \
	valid = false; \
} while(0)

bool scfg_parse(struct server_config *scfg, char *buf,
		notification_cb_t notification_cb)
{
	unsigned lineno;
	char *pos;
	bool valid = true;

	assert_return(scfg && buf, false);

	pos = buf;

	if (!config_parse_header(SERVER_CFG_HEADER, &pos, &lineno)) {
		INVALID("missing/invalid header");
		goto out;
	}

	while (true) {
		int key;
		const char *keyname;
		struct cfg_value value;

		if (!config_parse_line(scfg->filename, &pos, scfg_key_map, &key,
				       &keyname, &value, !!notification_cb, &lineno))
			break;

		/* FIXME: Improve error reporting */
		if (key == SCFG_KEY_INVALID) {
			INVALID("invalid line in config file");
			continue;
		}

		debug(DBG_CFG, "%s: key %s", scfg->filename, keyname);

		switch (key) {
		case SCFG_KEY_TYPE:
			if (scfg->type != SERVER_TYPE_UNDEFINED)
				INVALID("type defined multiple times");
			else if (streq(value.str, "proxy"))
				scfg->type = SERVER_TYPE_PROXY;
			else if (streq(value.str, "announce"))
				scfg->type = SERVER_TYPE_ANNOUNCE;
			else
				INVALID("unknown type: %s", value.str);
			break;

		case SCFG_KEY_NAME:
			if (scfg->pretty_name)
				INVALID("name defined multiple times");
			else if (empty_str(value.str))
				INVALID("name is an empty string");
			else if (!(scfg->pretty_name = xstrdup(value.str)))
				INVALID("strdup: %m");
			break;

		case SCFG_KEY_PORT:
			if (scfg->announce_port != 0)
				INVALID("port defined multiple times");
			else
				scfg->announce_port = value.uint16;
			break;

		case SCFG_KEY_LOCAL:
			if (!handle_dns(scfg, SCFG_KEY_LOCAL, &value,
					notification_cb))
				INVALID("handle_dns failed");
			break;

		case SCFG_KEY_REMOTE:
			if (!handle_dns(scfg, SCFG_KEY_REMOTE, &value,
					notification_cb))
				INVALID("handle_dns failed");
			break;

		case SCFG_KEY_IDLE_TIMEOUT:
			if (scfg->idle_timeout != 0)
				INVALID("idle_timeout already set");
			else
				scfg->idle_timeout = value.uint16;
			break;

		case SCFG_KEY_STOP_METHOD:
			if (scfg->stop_method != SERVER_STOP_METHOD_UNDEFINED)
				INVALID("stop method defined multiple times");
			else if (streq(value.str, "exec"))
				scfg->stop_method = SERVER_STOP_METHOD_EXEC;
			else if (streq(value.str, "rcon"))
				scfg->stop_method = SERVER_STOP_METHOD_RCON;
			else if (streq(value.str, "systemd"))
				scfg->stop_method = SERVER_STOP_METHOD_SYSTEMD;
			else
				INVALID("unknown stop method: %s", value.str);
			break;

		case SCFG_KEY_START_METHOD:
			if (scfg->start_method != SERVER_START_METHOD_UNDEFINED)
				INVALID("start method defined multiple times");
			else if (streq(value.str, "exec"))
				scfg->start_method = SERVER_START_METHOD_EXEC;
			else if (streq(value.str, "systemd"))
				scfg->start_method = SERVER_START_METHOD_SYSTEMD;
			else
				INVALID("unknown start method: %s", value.str);
			break;

		case SCFG_KEY_STOP_EXEC:
			if (scfg->stop_exec)
				INVALID("stop exec defined multiple times");
			else if (!(scfg->stop_exec = xstrdup(value.str)))
				INVALID("strdup: %m");
			break;

		case SCFG_KEY_START_EXEC:
			if (scfg->start_exec)
				INVALID("start exec defined multiple times");
			else if (!(scfg->start_exec = xstrdup(value.str)))
				INVALID("strdup: %m");
			break;

		case SCFG_KEY_RCON:
			if (!handle_dns(scfg, SCFG_KEY_RCON, &value,
					notification_cb))
				INVALID("handle_dns failed");
			break;

		case SCFG_KEY_RCON_PASSWORD:
			if (scfg->rcon_password)
				INVALID("rcon_password defined multiple times");
			else if (!(scfg->rcon_password = xstrdup(value.str)))
				INVALID("strdup: %m");
			break;

		case SCFG_KEY_SYSTEMD_SERVICE:
			if (scfg->systemd_service)
				INVALID("systemd_service defined multiple times");
			else {
				const char *suffix;
				char *tmp;

				suffix = strrchr(value.str, '.');
				if (!suffix || !streq(suffix, ".service")) {
					tmp = zmalloc(strlen(value.str) +
						      STRLEN(".service") + 1);
					if (tmp)
						sprintf(tmp, "%s.service",
							value.str);
				} else
					tmp = xstrdup(value.str);

				if (!tmp) {
					INVALID("malloc/strdup: %m");
					break;
				}

				scfg->systemd_service = tmp;
				scfg->systemd_obj = 
					systemd_object_path(scfg->systemd_service);
				if (!scfg->systemd_obj)
					INVALID("object_path: %m");
			}

			break;

		case SCFG_KEY_INVALID:
		default:
			INVALID("invalid line");
			break;
		}
	}

out:
	return valid;
}

void scfg_delete(struct server_config *scfg)
{
	struct saddr *saddr, *tmp;
	struct dns_async *dns;

	xfree(scfg->filename);
	xfree(scfg->pretty_name);
	xfree(scfg->stop_exec);
	xfree(scfg->start_exec);
	/* FIXME: use free_password */
	xfree(scfg->rcon_password);
	xfree(scfg->systemd_service);
	xfree(scfg->systemd_obj);

	list_for_each_entry_safe(saddr, tmp, &scfg->remotes, list) {
		list_del(&saddr->list);
		xfree(saddr);
	}

	list_for_each_entry_safe(saddr, tmp, &scfg->rcons, list) {
		list_del(&saddr->list);
		xfree(saddr);
	}

	list_for_each_entry_safe(saddr, tmp, &scfg->locals, list) {
		list_del(&saddr->list);
		xfree(saddr);
	}

	list_for_each_entry(dns, &scfg->dnslookups, list)
		gai_cancel(&dns->gcb);
}

bool scfg_init(struct server_config *scfg, const char *filename)
{
	assert_return(scfg, false);

	if (filename) {
		scfg->filename = xstrdup(filename);
		if (!scfg->filename) {
			error("strdup: %m");
			return false;
		}
	}
	scfg->type = SERVER_TYPE_UNDEFINED;
	scfg->pretty_name = NULL;
	scfg->announce_port = 0;
	scfg->idle_timeout = 0;
	scfg->stop_method = SERVER_STOP_METHOD_UNDEFINED;
	scfg->start_method = SERVER_START_METHOD_UNDEFINED;
	scfg->stop_exec = NULL;
	scfg->start_exec = NULL;
	scfg->rcon_password = NULL;
	scfg->systemd_service = NULL;
	scfg->systemd_obj = NULL;
	INIT_LIST_HEAD(&scfg->remotes);
	INIT_LIST_HEAD(&scfg->locals);
	INIT_LIST_HEAD(&scfg->rcons);
	INIT_LIST_HEAD(&scfg->dnslookups);
	return true;
}

static void eat_whitespace_and_comments(char **pos, unsigned *lineno)
{
	assert_return(pos && *pos && lineno);

	while (true) {
		while (**pos == ' ' ||
		       **pos == '\f' ||
		       **pos == '\r' ||
		       **pos == '\t' ||
		       **pos == '\v')
			(*pos)++;

		if (**pos == '\n') {
			(*lineno)++;
			(*pos)++;
			continue;
		}

		if (**pos != '#')
			return;

		while (**pos != '\n' && **pos != '\0')
			(*pos)++;
	}
}

static char *get_line(char **pos, unsigned *lineno)
{
	char *begin, *end;

	assert_return(pos && *pos && lineno, NULL);

	(*lineno)++;

	eat_whitespace_and_comments(pos, lineno);

	begin = *pos;

	if (*begin == '\0')
		return NULL;

	end = begin;
	while (*end != '\n' && *end != '\0')
		end++;

	if (*end == '\0')
		*pos = end;
	else
		*pos = end + 1;

	while (isspace(*end)) {
		*end = '\0';
		end--;
	}

	return begin;
}

static bool dnslookup(const char *name, uint16_t port, struct cfg_value *rvalue,
		      unsigned *naddrs, bool async)
{
	struct sockaddr_in *in4;
	struct sockaddr_in6 *in6;
	struct dns_async tmp;
	struct dns_async *dns;
	int mode = async ? GAI_NOWAIT : GAI_WAIT;
	struct addrinfo *results = NULL, *ai;
	struct saddr *saddr = NULL;
	bool rv = false;
	int r;

	assert_return(!empty_str(name) && strlen(name) < sizeof(dns->name) &&
			      port > 0 && rvalue,
		      false);

	if (async) {
		rvalue->type = CFG_VAL_TYPE_ASYNC_ADDRS;
		rvalue->dns_async = NULL;
		dns = zmalloc(sizeof(*dns));
		if (!dns) {
			error("async DNS lookup of %s failed: %m", name);
			goto out;
		}
		debug(DBG_DNS, "doing async DNS lookup of %s: %p", name, dns);
	} else {
		memset(&tmp, 0, sizeof(tmp));
		dns = &tmp;
		debug(DBG_DNS, "doing sync DNS lookup of %s", name);
	}

	sprintf(dns->name, "%s", name);
	sprintf(dns->port, "%" PRIu16, port);

	dns->req.ai_family = AF_UNSPEC;
	dns->req.ai_socktype = SOCK_STREAM;
	dns->req.ai_protocol = 0;
	dns->req.ai_flags = AI_NUMERICSERV;

	dns->sev.sigev_notify = SIGEV_SIGNAL;
	dns->sev.sigev_signo = SIGUSR1;
	dns->sev.sigev_value.sival_ptr = dns;

	dns->gcb.ar_name = dns->name;
	dns->gcb.ar_service = dns->port;
	dns->gcb.ar_request = &dns->req;

	struct gaicb *gcbs[] = { &dns->gcb };

	r = getaddrinfo_a(mode, gcbs, ARRAY_SIZE(gcbs), &dns->sev);
	if (r != 0) {
		error("getaddrinfo(%s:%" PRIu16 "): %s", name, port,
		      gai_strerror(r));
		goto out;
	}

	if (async) {
		rvalue->dns_async = dns;
		rv = true;
		goto out;
	}

	results = dns->gcb.ar_result;

	/* FIXME: parts can be shared with the async cb? */
	for (ai = results; ai; ai = ai->ai_next) {
		saddr = zmalloc(sizeof(*saddr));
		if (!saddr) {
			error("sync DNS lookup of %s failed: %m", name);
			goto out;
		}

		switch (ai->ai_family) {
		case AF_INET:
			in4 = (struct sockaddr_in *)ai->ai_addr;
			saddr_set_ipv4(saddr, in4->sin_addr.s_addr,
				       in4->sin_port);
			debug(DBG_CFG, "addrstr: %s", saddr->addrstr);
			list_add(&saddr->list, &rvalue->saddrs);
			(*naddrs)++;
			break;

		case AF_INET6:
			in6 = (struct sockaddr_in6 *)ai->ai_addr;
			saddr_set_ipv6(saddr, &in6->sin6_addr, in6->sin6_port);
			debug(DBG_CFG, "addrstr: %s", saddr->addrstr);
			list_add(&saddr->list, &rvalue->saddrs);
			(*naddrs)++;
			break;

		default:
			error("getaddrinfo(%s:%s): unknown address family (%i)",
			      dns->name, dns->port, ai->ai_family);
			xfree(saddr);
			break;
		}
	}

	rv = true;

out:
	freeaddrinfo(results);
	return rv;
}

bool strtosockaddrs(const char *str, struct cfg_value *rvalue, bool async)
{
	struct saddr *saddr;
	uint16_t port;
	char *tmp;
	struct list_head *list;
	unsigned naddrs = 0;

	assert_return(!empty_str(str) && rvalue, false);

	rvalue->type = CFG_VAL_TYPE_ADDRS;
	list = &rvalue->saddrs;
	INIT_LIST_HEAD(list);

	if (*str == '[') {
		/* IPv6, [a:b:c...h]:p or [*]:p */
		debug(DBG_CFG, "attempting to parse IPv6 addr (%s)", str);

		str++;
		tmp = strchr(str, ']');
		if (!tmp)
			goto error;
		*tmp = '\0';

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		/* early list_add to make sure saddr is free():d on error */
		list_add(&saddr->list, list);

		if (streq(str, "*"))
			saddr->in6.sin6_addr = in6addr_any;
		else if (inet_pton(AF_INET6, str, &saddr->in6.sin6_addr) <= 0)
			goto error;

		tmp++;
		if (*tmp != ':')
			goto error;

		tmp++;
		if (strtou16_strict(tmp, &port) < 0)
			goto error;

		saddr_set_ipv6(saddr, NULL, htons(port));
		naddrs++;

	} else if (*str == '*') {
		/* IPv4, *:p */
		debug(DBG_CFG, "attempting to parse IPv4 addr (%s)", str);

		str++;
		if (*str != ':')
			goto error;

		str++;
		if (strtou16_strict(str, &port) < 0)
			goto error;

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
		list_add(&saddr->list, list);
		naddrs++;

	} else if ((tmp = strchr(str, ':'))) {
		/* IPv4, a.b.c.d:p or IPv4/6 hostname:p */
		debug(DBG_CFG, "attempting to parse IPv4 addr or hostname (%s)",
		      str);

		*tmp = '\0';
		tmp++;
		if (strtou16_strict(tmp, &port) < 0)
			goto error;

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		if (inet_pton(AF_INET, str, &saddr->in4.sin_addr) > 0) {
			debug(DBG_CFG, "got an IPv4:port (%s:%" PRIu16 ")", str,
			      port);
			saddr_set_ipv4(saddr, saddr->in4.sin_addr.s_addr,
				       htons(port));
			list_add(&saddr->list, list);
			naddrs++;
			goto success;
		}

		xfree(saddr);
		debug(DBG_CFG, "maybe got a hostname:port (%s:%" PRIu16 ")",
		      str, port);
		if (!dnslookup(str, port, rvalue, &naddrs, async))
			goto error;

	} else if (strtou16_strict(tmp, &port) == 0) {
		/* Port */
		debug(DBG_CFG, "attempting to parse a port number (%s)", str);

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv6(saddr, &in6addr_any, htons(port));
		list_add(&saddr->list, list);
		naddrs++;

		saddr = zmalloc(sizeof(*saddr));
		if (!saddr)
			goto error;

		saddr_set_ipv4(saddr, INADDR_ANY, htons(port));
		list_add(&saddr->list, list);
		naddrs++;

	} else {
		/* Unknown */
		goto error;
	}

success:
	switch (rvalue->type) {
	case CFG_VAL_TYPE_ADDRS:
		if (list_empty(list) || naddrs == 0) {
			error("empty address list");
			return false;
		}

		debug(DBG_CFG, "parsed to %u addresses", naddrs);
		return true;

	case CFG_VAL_TYPE_ASYNC_ADDRS:
		debug(DBG_CFG, "looking up address asynchronously");
		return true;

	default:
		error("invalid rvalue type");
		rvalue->type = CFG_VAL_TYPE_INVALID;
		break;
	}

error:
	if (rvalue->type == CFG_VAL_TYPE_ADDRS && !list_empty(list)) {
		struct saddr *tmp;

		list_for_each_entry_safe(saddr, tmp, list, list) {
			list_del(&saddr->list);
			xfree(saddr);
		}
	}
	return false;
}

/* Returns true if there's data left to parse in buf */
bool config_parse_line(const char *filename, char **buf,
		       struct cfg_key_value_map *kvmap, int *rkey,
		       const char **rkeyname, struct cfg_value *rvalue,
		       bool async_dns, unsigned *lineno)
{
	char *line, *pos, *key, *value;
	size_t linelen;
	int i;

	assert_return(buf && *buf && kvmap && rkey && rkeyname && rvalue && lineno,
		      false);

	line = get_line(buf, lineno);
	if (!line)
		return false;

	debug(DBG_CFG, "%s: parsing cfg line %u: %s", filename, *lineno, line);

	linelen = strlen(line);
	key = line;

	pos = memchr(line, '=', linelen);
	if (!pos)
		goto error;

	value = pos + 1;
	*pos = '\0';

	while (isspace(*(--pos)))
	       *pos = '\0';

	while (isspace(*value))
		value++;

	if (*value == '\0')
		goto error;

	for (i = 0; kvmap[i].key_name; i++) {
		if (streq(kvmap[i].key_name, key))
			break;
	}

	if (!kvmap[i].key_name)
		goto error;

	switch (kvmap[i].value_type) {
	case CFG_VAL_TYPE_STRING:
		rvalue->type = CFG_VAL_TYPE_STRING;
		rvalue->str = value;
		break;

	case CFG_VAL_TYPE_UINT16: {
		uint16_t v;

		if (strtou16_strict(value, &v) < 0)
			goto error;

		rvalue->type = CFG_VAL_TYPE_UINT16;
		rvalue->uint16 = v;
		break;
	}

	case CFG_VAL_TYPE_ASYNC_ADDRS:
		error("CFG_VAL_TYPE_ASYNC_ADDRS is a return value");
		_fallthrough_;

	case CFG_VAL_TYPE_ADDRS:
		if (!strtosockaddrs(value, rvalue, async_dns))
			goto error;

		switch (rvalue->type) {
		case CFG_VAL_TYPE_ADDRS:
			if (list_empty(&rvalue->saddrs)) {
				error("empty address list");
				goto error;
			}
			break;

		case CFG_VAL_TYPE_ASYNC_ADDRS:
			if (!async_dns) {
				error("unexpected async dns result");
				goto error;
			}

			if (!rvalue->dns_async) {
				error("dns_async not set");
				goto error;
			}
			break;

		default:
			error("invalid type returned from strtosockaddrs");
			goto error;
		}
		break;

	case CFG_VAL_TYPE_BOOL:
		if (strcaseeq(value, "yes") || strcaseeq(value, "true")) {
			rvalue->type = CFG_VAL_TYPE_BOOL;
			rvalue->boolean = true;
		} else if (strcaseeq(value, "no") ||
			   strcaseeq(value, "false")) {
			rvalue->type = CFG_VAL_TYPE_BOOL;
			rvalue->boolean = false;
		} else {
			error("invalid boolean value (%s)", value);
			goto error;
		}
		break;

	case CFG_VAL_TYPE_INVALID:
		_fallthrough_;
	default:
		goto error;
	}

	/* sanity check */
	if ((rvalue->type != kvmap[i].value_type) &&
	    ((kvmap[i].value_type != CFG_VAL_TYPE_ASYNC_ADDRS) &&
	     (rvalue->type != CFG_VAL_TYPE_ADDRS))) {
		error("rvalue->type != kvmap->type");
		goto error;
	}

	*rkey = kvmap[i].key_value;
	*rkeyname = kvmap[i].key_name;
	return true;

error:
	error("%s: invalid config line: %u:%s", filename, *lineno, line);
	rvalue->type = CFG_VAL_TYPE_INVALID;
	*rkey = 0;
	*rkeyname = NULL;
	return true;
}

bool config_parse_header(const char *title, char **buf, unsigned *lineno)
{
	char *line;

	assert_return(!empty_str(title) && buf && *buf && lineno, false);

	*lineno = 0;

	line = get_line(buf, lineno);
	if (line) {
		char titlehdr[strlen(title) + 3];

		sprintf(titlehdr, "[%s]", title);
		if (streq(line, titlehdr))
			return true;
	}

	return false;
}

bool is_valid_server_config_filename(struct dirent *dent, const char *filename)
{
	const char *suffix;

	assert_return(!(dent && filename) && !(!dent && !filename), false);

	/* Maybe accept DT_LNK? */
	if (dent) {
		switch (dent->d_type) {
		case DT_UNKNOWN:
			_fallthrough_;
		case DT_REG:
			break;
		default:
			return false;
		}
		filename = dent->d_name;
	}

	if (empty_str(filename))
		return false;
	if (filename[0] == '.')
		return false;
	if ((suffix = strrchr(filename, '.')) == NULL)
		return false;
	if (!streq(suffix, "." SERVER_CONFIG_FILE_SUFFIX))
		return false;

	return true;
}