/*	$OpenBSD: lka.c,v 1.58 2009/06/05 20:43:57 pyr Exp $	*/

/*
 * Copyright (c) 2008 Pierre-Yves Ritschard <pyr@openbsd.org>
 * Copyright (c) 2008 Gilles Chehade <gilles@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */

#include <sys/types.h>
#include <sys/queue.h>
#include <sys/tree.h>
#include <sys/param.h>
#include <sys/socket.h>
#include <sys/wait.h>

#include <netinet/in.h>
#include <arpa/inet.h>

#include <ctype.h>
#include <errno.h>
#include <event.h>
#include <netdb.h>
#include <pwd.h>
#include <regex.h>
#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include <keynote.h>

#include "smtpd.h"

__dead void	lka_shutdown(void);
void		lka_sig_handler(int, short, void *);
void		lka_dispatch_parent(int, short, void *);
void		lka_dispatch_mfa(int, short, void *);
void		lka_dispatch_smtp(int, short, void *);
void		lka_dispatch_queue(int, short, void *);
void		lka_dispatch_runner(int, short, void *);
void		lka_dispatch_mta(int, short, void *);
void		lka_setup_events(struct smtpd *);
void		lka_disable_events(struct smtpd *);
int		lka_verify_mail(struct smtpd *, struct path *);
int		lka_resolve_mail(struct smtpd *, struct rule *, struct path *);
int		lka_forward_file(struct passwd *);
size_t		lka_expand(char *, size_t, struct path *);
int		aliases_exist(struct smtpd *, char *);
int		aliases_get(struct smtpd *, struct aliaseslist *, char *);
int		lka_resolve_alias(struct smtpd *, struct path *, struct alias *);
int		lka_parse_include(char *);
int		lka_check_source(struct smtpd *, struct map *, struct sockaddr_storage *);
int		lka_match_mask(struct sockaddr_storage *, struct netaddr *);
int		aliases_virtual_get(struct smtpd *, struct aliaseslist *, struct path *);
int		aliases_virtual_exist(struct smtpd *, struct path *);
int		lka_resolve_path(struct smtpd *, struct path *);
void		lka_expand_rcpt(struct smtpd *, struct aliaseslist *, struct lkasession *);
int		lka_expand_rcpt_iteration(struct smtpd *, struct aliaseslist *, struct lkasession *);
void		lka_rcpt_action(struct smtpd *, struct path *);
void		lka_clear_aliaseslist(struct aliaseslist *);
int		lka_encode_credentials(char *, size_t, char *);
struct rule    *ruleset_match(struct smtpd *, struct path *, struct sockaddr_storage *);

void
lka_sig_handler(int sig, short event, void *p)
{
	int status;
	pid_t pid;

	switch (sig) {
	case SIGINT:
	case SIGTERM:
		lka_shutdown();
		break;
	case SIGCHLD:
		do {
			pid = waitpid(-1, &status, WNOHANG);
		} while (pid > 0 || (pid == -1 && errno == EINTR));
		break;
	default:
		fatalx("lka_sig_handler: unexpected signal");
	}
}

void
lka_dispatch_parent(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_PARENT];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_parent: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		case IMSG_CONF_START:
			if ((env->sc_rules_reload = calloc(1, sizeof(*env->sc_rules))) == NULL)
				fatal("mfa_dispatch_parent: calloc");
			if ((env->sc_maps_reload = calloc(1, sizeof(*env->sc_maps))) == NULL)
				fatal("mfa_dispatch_parent: calloc");
			TAILQ_INIT(env->sc_rules_reload);
			TAILQ_INIT(env->sc_maps_reload);
			break;
		case IMSG_CONF_RULE: {
			struct rule *rule = imsg.data;

			IMSG_SIZE_CHECK(rule);

			rule = calloc(1, sizeof(*rule));
			if (rule == NULL)
				fatal("mfa_dispatch_parent: calloc");
			*rule = *(struct rule *)imsg.data;

			TAILQ_INIT(&rule->r_conditions);
			TAILQ_INSERT_TAIL(env->sc_rules_reload, rule, r_entry);
			break;
		}
		case IMSG_CONF_CONDITION: {
			struct rule *r = TAILQ_LAST(env->sc_rules_reload, rulelist);
			struct cond *cond = imsg.data;

			IMSG_SIZE_CHECK(cond);

			cond = calloc(1, sizeof(*cond));
			if (cond == NULL)
				fatal("mfa_dispatch_parent: calloc");
			*cond = *(struct cond *)imsg.data;

			TAILQ_INSERT_TAIL(&r->r_conditions, cond, c_entry);
			break;
		}
		case IMSG_CONF_MAP: {
			struct map *m = imsg.data;

			IMSG_SIZE_CHECK(m);

			m = calloc(1, sizeof(*m));
			if (m == NULL)
				fatal("mfa_dispatch_parent: calloc");
			*m = *(struct map *)imsg.data;

			TAILQ_INIT(&m->m_contents);
			TAILQ_INSERT_TAIL(env->sc_maps_reload, m, m_entry);
			break;
		}
		case IMSG_CONF_RULE_SOURCE: {
			struct rule *rule = TAILQ_LAST(env->sc_rules_reload, rulelist);
			char *sourcemap = imsg.data;
			void *temp = env->sc_maps;

			/* map lookup must be done in the reloaded conf */
			env->sc_maps = env->sc_maps_reload;
			rule->r_sources = map_findbyname(env, sourcemap);
			if (rule->r_sources == NULL)
				fatalx("maps inconsistency");
			env->sc_maps = temp;
			break;
		}
		case IMSG_CONF_MAP_CONTENT: {
			struct map *m = TAILQ_LAST(env->sc_maps_reload, maplist);
			struct mapel *mapel = imsg.data;
			
			IMSG_SIZE_CHECK(mapel);
			
			mapel = calloc(1, sizeof(*mapel));
			if (mapel == NULL)
				fatal("mfa_dispatch_parent: calloc");
			*mapel = *(struct mapel *)imsg.data;

			TAILQ_INSERT_TAIL(&m->m_contents, mapel, me_entry);
			break;
		}
		case IMSG_CONF_END: {			
			/* switch and destroy old ruleset */
			if (env->sc_rules)
				purge_config(env, PURGE_RULES);
			if (env->sc_maps)
				purge_config(env, PURGE_MAPS);
			env->sc_rules = env->sc_rules_reload;
			env->sc_maps = env->sc_maps_reload;
			break;
		}
		case IMSG_PARENT_FORWARD_OPEN: {
			int fd;
			struct forward_req	*fwreq = imsg.data;
			struct lkasession	key;
			struct lkasession	*lkasession;

			IMSG_SIZE_CHECK(fwreq);

			key.id = fwreq->id;
			lkasession = SPLAY_FIND(lkatree, &env->lka_sessions, &key);
			if (lkasession == NULL)
				fatal("lka_dispatch_parent: lka session is gone");
			fd = imsg_get_fd(ibuf);
			--lkasession->pending;

			if (fd == -1) {
				if (! fwreq->status) {
					lkasession->ss.code = 530;
					lkasession->flags |= F_ERROR;
				}
				else {
					struct alias *alias;
					struct message message;

					alias = calloc(1, sizeof(struct alias));
					if (alias == NULL)
						fatal("lka_dispatch_parent: calloc");

					alias_parse(alias, fwreq->pw_name);

					message = lkasession->message;

					bzero(&message.recipient, sizeof(struct path));
					strlcpy(message.recipient.domain, lkasession->path.domain,
					    sizeof(message.recipient.domain));

					lka_resolve_alias(env, &message.recipient, alias);
					lka_rcpt_action(env, &message.recipient);

					if (lka_expand(message.recipient.rule.r_value.path,
						sizeof(message.recipient.rule.r_value.path),
						&message.recipient) >=
					    sizeof(message.recipient.rule.r_value.path)) {
						log_debug("expansion failed...");
					}

					imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
					    IMSG_QUEUE_SUBMIT_ENVELOPE, 0, 0, -1,
					    &message, sizeof(struct message));

					if (! lkasession->pending)
						imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
						    IMSG_QUEUE_COMMIT_ENVELOPES, 0, 0, -1,
						    &message, sizeof(struct message));
					break;
				}
			}
			else {
				if (! forwards_get(fd, &lkasession->aliaseslist)) {
					lkasession->ss.code = 530;
					lkasession->flags |= F_ERROR;
				}
				close(fd);
			}
			lka_expand_rcpt(env, &lkasession->aliaseslist, lkasession);
			break;
		}
		default:
			log_warnx("lka_dispatch_parent: got imsg %d",
			    imsg.hdr.type);
			fatalx("lka_dispatch_parent: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_dispatch_mfa(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_MFA];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_mfa: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		case IMSG_LKA_MAIL: {
			struct submit_status	 *ss = imsg.data;

			IMSG_SIZE_CHECK(ss);

			ss->code = 530;

			if (ss->u.path.user[0] == '\0' && ss->u.path.domain[0] == '\0')
				ss->code = 250;
			else
				if (lka_verify_mail(env, &ss->u.path))
					ss->code = 250;

			imsg_compose_event(ibuf, IMSG_LKA_MAIL, 0, 0, -1,
				ss, sizeof(*ss));

			break;
		}
		case IMSG_LKA_RCPT: {
			struct submit_status	*ss = imsg.data;
			struct message		message;
			struct lkasession	*lkasession;
			struct forward_req	 fwreq;
			int ret;

			IMSG_SIZE_CHECK(ss);

			ss->code = 530;
			
			if (IS_RELAY(ss->u.path.rule.r_action)) {
				ss->code = 250;
				message = ss->msg;
				message.recipient = ss->u.path;
				imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
				    IMSG_QUEUE_SUBMIT_ENVELOPE, 0, 0, -1,
				    &message, sizeof(struct message));
				imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
				    IMSG_QUEUE_COMMIT_ENVELOPES, 0, 0, -1,
				    &message, sizeof(struct message));
				break;
			}

			if (! lka_resolve_path(env, &ss->u.path)) {
				imsg_compose_event(ibuf, IMSG_LKA_RCPT, 0, 0, -1,
				    ss, sizeof(*ss));
				break;
			}

			ss->code = 250;

			lkasession = calloc(1, sizeof(struct lkasession));
			if (lkasession == NULL)
				fatal("lka_dispatch_mfa: calloc");
			lkasession->id = queue_generate_id();
			lkasession->path = ss->u.path;
			lkasession->message = ss->msg;
			lkasession->ss = *ss;

			TAILQ_INIT(&lkasession->aliaseslist);

			SPLAY_INSERT(lkatree, &env->lka_sessions, lkasession);

			ret = 0;
			if (lkasession->path.flags & F_PATH_ACCOUNT) {
				fwreq.id = lkasession->id;
				(void)strlcpy(fwreq.pw_name, ss->u.path.pw_name, sizeof(fwreq.pw_name));
				imsg_compose_event(env->sc_ibufs[PROC_PARENT], IMSG_PARENT_FORWARD_OPEN, 0, 0, -1,
				    &fwreq, sizeof(fwreq));
				++lkasession->pending;
				break;
			}
			else if (lkasession->path.flags & F_PATH_ALIAS) {
				ret = aliases_get(env, &lkasession->aliaseslist, lkasession->path.user);
			}
			else if (lkasession->path.flags & F_PATH_VIRTUAL) {
				ret = aliases_virtual_get(env, &lkasession->aliaseslist, &lkasession->path);
			}
			else
				fatal("lka_dispatch_mfa: path with illegal flag");

			if (ret == 0) {
				/* No aliases ... */
				ss->code = 530;
				imsg_compose_event(ibuf, IMSG_LKA_RCPT, 0, 0,
				    -1, ss, sizeof(*ss));
				break;
			}

			lka_expand_rcpt(env, &lkasession->aliaseslist, lkasession);

			break;
		}
		default:
			log_warnx("lka_dispatch_mfa: got imsg %d",
			    imsg.hdr.type);
			fatalx("lka_dispatch_mfa: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_dispatch_mta(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_MTA];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_mta: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		case IMSG_LKA_SECRET: {
			struct secret	*query = imsg.data;
			char		*secret = NULL;
			char		*map = "secrets";

			IMSG_SIZE_CHECK(query);

			secret = map_dblookup(env, map, query->host);

			log_debug("secret for %s %s", query->host,
			    secret ? "found" : "not found");
			
			query->secret[0] = '\0';

			if (secret == NULL) {
				log_warnx("failed to lookup %s in the %s map",
				    query->host, map);
			} else if (! lka_encode_credentials(query->secret,
			    sizeof(query->secret), secret)) {
				log_warnx("parse error for %s in the %s map",
				    query->host, map);
			}

			imsg_compose_event(ibuf, IMSG_LKA_SECRET, 0, 0, -1, query,
			    sizeof(*query));
			free(secret);
			break;
		}

		case IMSG_DNS_A:
		case IMSG_DNS_MX: {
			struct dns	*query = imsg.data;

			IMSG_SIZE_CHECK(query);
			dns_async(env, ibuf, imsg.hdr.type, query);
			break;
		}

		default:
			log_warnx("lka_dispatch_mta: got imsg %d",
			    imsg.hdr.type);
			fatalx("lka_dispatch_mta: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_dispatch_smtp(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_SMTP];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_smtp: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		case IMSG_DNS_PTR: {
			struct dns	*query = imsg.data;

			IMSG_SIZE_CHECK(query);
			dns_async(env, ibuf, IMSG_DNS_PTR, query);
			break;
		}
		default:
			log_warnx("lka_dispatch_smtp: got imsg %d",
			    imsg.hdr.type);
			fatalx("lka_dispatch_smtp: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_dispatch_queue(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_QUEUE];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_queue: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		default:
			log_warnx("lka_dispatch_queue: got imsg %d",
			   imsg.hdr.type);
			fatalx("lka_dispatch_queue: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_dispatch_runner(int sig, short event, void *p)
{
	struct smtpd		*env = p;
	struct imsgbuf		*ibuf;
	struct imsg		 imsg;
	ssize_t			 n;

	ibuf = env->sc_ibufs[PROC_RUNNER];

	if (event & EV_READ) {
		if ((n = imsg_read(ibuf)) == -1)
			fatal("imsg_read_error");
		if (n == 0) {
			/* this pipe is dead, so remove the event handler */
			event_del(&ibuf->ev);
			event_loopexit(NULL);
			return;
		}
	}

	if (event & EV_WRITE) {
		if (msgbuf_write(&ibuf->w) == -1)
			fatal("msgbuf_write");
	}

	for (;;) {
		if ((n = imsg_get(ibuf, &imsg)) == -1)
			fatalx("lka_dispatch_runner: imsg_get error");
		if (n == 0)
			break;

		switch (imsg.hdr.type) {
		default:
			log_warnx("lka_dispatch_runner: got imsg %d",
			    imsg.hdr.type);
			fatalx("lka_dispatch_runner: unexpected imsg");
		}
		imsg_free(&imsg);
	}
	imsg_event_add(ibuf);
}

void
lka_shutdown(void)
{
	log_info("lookup agent exiting");
	_exit(0);
}

void
lka_setup_events(struct smtpd *env)
{
}

void
lka_disable_events(struct smtpd *env)
{
}

pid_t
lka(struct smtpd *env)
{
	pid_t		 pid;
	struct passwd	*pw;

	struct event	 ev_sigint;
	struct event	 ev_sigterm;
	struct event	 ev_sigchld;

	struct peer peers[] = {
		{ PROC_PARENT,	lka_dispatch_parent },
		{ PROC_MFA,	lka_dispatch_mfa },
		{ PROC_QUEUE,	lka_dispatch_queue },
		{ PROC_SMTP,	lka_dispatch_smtp },
		{ PROC_RUNNER,	lka_dispatch_runner },
		{ PROC_MTA,	lka_dispatch_mta }
	};

	switch (pid = fork()) {
	case -1:
		fatal("lka: cannot fork");
	case 0:
		break;
	default:
		return (pid);
	}

	purge_config(env, PURGE_EVERYTHING);

	pw = env->sc_pw;

	smtpd_process = PROC_LKA;
	setproctitle("%s", env->sc_title[smtpd_process]);

#ifndef DEBUG
	if (setgroups(1, &pw->pw_gid) ||
	    setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) ||
	    setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid))
		fatal("lka: cannot drop privileges");
#endif

	event_init();
	SPLAY_INIT(&env->lka_sessions);

	signal_set(&ev_sigint, SIGINT, lka_sig_handler, env);
	signal_set(&ev_sigterm, SIGTERM, lka_sig_handler, env);
	signal_set(&ev_sigchld, SIGCHLD, lka_sig_handler, env);
	signal_add(&ev_sigint, NULL);
	signal_add(&ev_sigterm, NULL);
	signal_add(&ev_sigchld, NULL);
	signal(SIGPIPE, SIG_IGN);
	signal(SIGHUP, SIG_IGN);

	config_pipes(env, peers, nitems(peers));
	config_peers(env, peers, nitems(peers));

	lka_setup_events(env);
	event_dispatch();
	lka_shutdown();

	return (0);
}

int
lka_verify_mail(struct smtpd *env, struct path *path)
{
	struct rule *r;

	r = ruleset_match(env, path, NULL);
	if (r == NULL) {
		path->rule.r_action = A_RELAY;
		return 1;
	}

	path->rule = *r;
	if (r->r_action == A_MBOX ||
	    r->r_action == A_MAILDIR ||
	    r->r_action == A_EXT) {
		lka_resolve_mail(env, r, path);
		return 1;
	}

	return 1;
}

int
lka_resolve_mail(struct smtpd *env, struct rule *rule, struct path *path)
{
	char username[MAXLOGNAME];
	struct passwd *pw;
	char *p;

	(void)strlcpy(username, path->user, sizeof(username));

	for (p = &username[0]; *p != '\0' && *p != '+'; ++p)
		*p = tolower((int)*p);
	*p = '\0';

	if (aliases_virtual_exist(env, path))
		path->flags |= F_PATH_VIRTUAL;
	else if (aliases_exist(env, username))
		path->flags |= F_PATH_ALIAS;
	else {
		pw = getpwnam(username);
		if (pw == NULL)
			return 0;
		(void)strlcpy(path->pw_name, pw->pw_name,
		    sizeof(path->pw_name));
		if (lka_expand(path->rule.r_value.path,
		    sizeof(path->rule.r_value.path), path) >=
		    sizeof(path->rule.r_value.path))
			return 0;
	}

	return 1;
}

size_t
lka_expand(char *buf, size_t len, struct path *path)
{
	char *p, *pbuf;
	struct rule r;
	size_t ret;
	struct passwd *pw;

	bzero(r.r_value.path, MAXPATHLEN);
	pbuf = r.r_value.path;

	ret = 0;
	for (p = path->rule.r_value.path; *p != '\0'; ++p) {
		if (p == path->rule.r_value.path && *p == '~') {
			if (*(p + 1) == '/' || *(p + 1) == '\0') {
				pw = getpwnam(path->pw_name);
				if (pw == NULL)
					continue;

				ret += strlcat(pbuf, pw->pw_dir, len);
				if (ret >= len)
					return ret;
				pbuf += strlen(pw->pw_dir);
				continue;
			}

			if (*(p + 1) != '/') {
				char username[MAXLOGNAME];
				char *delim;

				ret = strlcpy(username, p + 1,
				    sizeof(username));
				delim = strchr(username, '/');
				if (delim == NULL && ret >= sizeof(username)) {
					continue;
				}

				if (delim != NULL) {
					*delim = '\0';
				}

				pw = getpwnam(username);
				if (pw == NULL)
					continue;

				ret += strlcat(pbuf, pw->pw_dir, len);
				if (ret >= len)
					return ret;
				pbuf += strlen(pw->pw_dir);
				p += strlen(username);
				continue;
			}
		}
		if (strncmp(p, "%a", 2) == 0) {
			ret += strlcat(pbuf, path->user, len);
			if (ret >= len)
				return ret;
			pbuf += strlen(path->user);
			++p;
			continue;
		}
		if (strncmp(p, "%u", 2) == 0) {
			ret += strlcat(pbuf, path->pw_name, len);
			if (ret >= len)
				return ret;
			pbuf += strlen(path->pw_name);
			++p;
			continue;
		}
		if (strncmp(p, "%d", 2) == 0) {
			ret += strlcat(pbuf, path->domain, len);
			if (ret >= len)
				return ret;
			pbuf += strlen(path->domain);
			++p;
			continue;
		}
		if (*p == '%' && isdigit((int)*(p+1)) && *(p+2) == 'a') {
			size_t idx;

			idx = *(p+1) - '0';
			if (idx < strlen(path->user))
				*pbuf++ = path->user[idx];
			p+=2;
			++ret;
			continue;
		}
		if (*p == '%' && isdigit((int)*(p+1)) && *(p+2) == 'u') {
			size_t idx;

			idx = *(p+1) - '0';
			if (idx < strlen(path->pw_name))
				*pbuf++ = path->pw_name[idx];
			p+=2;
			++ret;
			continue;
		}
		if (*p == '%' && isdigit((int)*(p+1)) && *(p+2) == 'd') {
			size_t idx;

			idx = *(p+1) - '0';
			if (idx < strlen(path->domain))
				*pbuf++ = path->domain[idx];
			p+=2;
			++ret;
			continue;
		}

		*pbuf++ = *p;
		++ret;
	}

	memcpy(path->rule.r_value.path, r.r_value.path, ret);

	return ret;
}

int
lka_resolve_alias(struct smtpd *env, struct path *path, struct alias *alias)
{
	switch (alias->type) {
	case ALIAS_USERNAME:
		log_debug("USERNAME: %s", alias->u.username);
		if (strlcpy(path->pw_name, alias->u.username,
			sizeof(path->pw_name)) >= sizeof(path->pw_name))
			return 0;
		if (path->user[0] == '\0') {
			if (strlcpy(path->user, alias->u.username,
				sizeof(path->user)) >= sizeof(path->user))
				return 0;
		}
		if (path->domain[0] == '\0') {
			if (strlcpy(path->domain, env->sc_hostname,
				sizeof(path->domain)) >= sizeof(path->domain))
				return 0;
		}
		break;

	case ALIAS_FILENAME:
		log_debug("FILENAME: %s", alias->u.filename);
		path->rule.r_action = A_FILENAME;
		strlcpy(path->u.filename, alias->u.filename,
		    sizeof(path->u.filename));
		break;

	case ALIAS_FILTER:
		log_debug("FILTER: %s", alias->u.filter);
		path->rule.r_action = A_EXT;
		strlcpy(path->rule.r_value.command, alias->u.filter + 2,
		    sizeof(path->rule.r_value.command));
		path->rule.r_value.command[strlen(path->rule.r_value.command) - 1] = '\0';
		break;

	case ALIAS_ADDRESS:
		log_debug("ADDRESS: %s@%s", alias->u.path.user, alias->u.path.domain);
		*path = alias->u.path;
		break;
	case ALIAS_INCLUDE:
		fatalx("lka_resolve_alias: unexpected type");
		break;
	}
	return 1;
}

void
lka_expand_rcpt(struct smtpd *env, struct aliaseslist *aliases, struct lkasession *lkasession)
{
	int	ret;
	struct alias	*alias;
	struct message	message;

	ret = 0;
	while (! (lkasession->flags & F_ERROR) &&
	    ! lkasession->pending && lkasession->iterations < 5) {
		++lkasession->iterations;
		ret = lka_expand_rcpt_iteration(env, &lkasession->aliaseslist, lkasession);
		if (ret == -1) {
			lkasession->ss.code = 530;
			lkasession->flags |= F_ERROR;
		}

		if (lkasession->pending || ret <= 0)
			break;
	}

	if (lkasession->pending)
		return;

	if (lkasession->flags & F_ERROR) {
		lka_clear_aliaseslist(&lkasession->aliaseslist);
		imsg_compose_event(env->sc_ibufs[PROC_MFA], IMSG_LKA_RCPT, 0, 0,
		    -1, &lkasession->ss, sizeof(struct submit_status));
	}
	else if (TAILQ_FIRST(&lkasession->aliaseslist) == NULL) {
		message = lkasession->message;
		message.recipient = lkasession->path;
		imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
		    IMSG_QUEUE_SUBMIT_ENVELOPE, 0, 0, -1,
		    &message, sizeof(struct message));
		imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
		    IMSG_QUEUE_COMMIT_ENVELOPES, 0, 0, -1,
		    &message, sizeof(struct message));
	}
	else {
		log_debug("a list of aliases is available");
		message = lkasession->message;
		while ((alias = TAILQ_FIRST(&lkasession->aliaseslist)) != NULL) {
			bzero(&message.recipient, sizeof(struct path));
			
			lka_resolve_alias(env, &message.recipient, alias);
			lka_rcpt_action(env, &message.recipient);
			
			imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
			    IMSG_QUEUE_SUBMIT_ENVELOPE, 0, 0, -1,
			    &message, sizeof(struct message));
			
			TAILQ_REMOVE(&lkasession->aliaseslist, alias, entry);
			free(alias);
		}
		imsg_compose_event(env->sc_ibufs[PROC_QUEUE],
		    IMSG_QUEUE_COMMIT_ENVELOPES, 0, 0, -1, &message,
		    sizeof(struct message));
	}
	SPLAY_REMOVE(lkatree, &env->lka_sessions, lkasession);
	free(lkasession);
}

int
lka_expand_rcpt_iteration(struct smtpd *env, struct aliaseslist *aliases, struct lkasession *lkasession)
{
	u_int8_t done = 1;
	struct alias *rmalias = NULL;
	struct alias *alias;
	struct forward_req fwreq;

	rmalias = NULL;
	TAILQ_FOREACH(alias, aliases, entry) {
		if (rmalias) {
			TAILQ_REMOVE(aliases, rmalias, entry);
			free(rmalias);
			rmalias = NULL;
		}
		
		if (alias->type == ALIAS_ADDRESS) {
			if (aliases_virtual_get(env, aliases, &alias->u.path)) {
				rmalias = alias;
				done = 0;
			}
		}
		
		else if (alias->type == ALIAS_USERNAME) {
			if (aliases_get(env, aliases, alias->u.username)) {
				done = 0;
				rmalias = alias;
			}
			else {
				done = 0;
				fwreq.id = lkasession->id;
				(void)strlcpy(fwreq.pw_name, alias->u.username, sizeof(fwreq.pw_name));
				imsg_compose_event(env->sc_ibufs[PROC_PARENT], IMSG_PARENT_FORWARD_OPEN, 0, 0, -1,
				    &fwreq, sizeof(fwreq));
				++lkasession->pending;
				rmalias = alias;
			}
		}
	}
	if (rmalias) {
		TAILQ_REMOVE(aliases, rmalias, entry);
		free(rmalias);
		rmalias = NULL;
	}

	if (!done && lkasession->iterations == 5)
		return -1;

	if (TAILQ_FIRST(aliases) == NULL)
		return 0;

	return 1;
}

int
lka_resolve_path(struct smtpd *env, struct path *path)
{
	char username[MAXLOGNAME];
	struct passwd *pw;
	char *p;

	(void)strlcpy(username, path->user, sizeof(username));

	for (p = &username[0]; *p != '\0' && *p != '+'; ++p)
		*p = tolower((int)*p);
	*p = '\0';

	if (aliases_virtual_exist(env, path))
		path->flags |= F_PATH_VIRTUAL;
	else if (aliases_exist(env, username))
		path->flags |= F_PATH_ALIAS;
	else {
		path->flags |= F_PATH_ACCOUNT;
		pw = getpwnam(username);
		if (pw == NULL)
			return 0;
		(void)strlcpy(path->pw_name, pw->pw_name,
		    sizeof(path->pw_name));
		if (lka_expand(path->rule.r_value.path,
		    sizeof(path->rule.r_value.path), path) >=
		    sizeof(path->rule.r_value.path))
			return 0;
	}

	return 1;
}

void
lka_rcpt_action(struct smtpd *env, struct path *path)
{
	struct rule *r;

	if (path->domain[0] == '\0')
		(void)strlcpy(path->domain, env->sc_hostname,
		    sizeof (path->domain));

	r = ruleset_match(env, path, NULL);
	if (r == NULL) {
		path->rule.r_action = A_RELAY;
		return;
	}

	path->rule = *r;
}

int
lkasession_cmp(struct lkasession *s1, struct lkasession *s2)
{
	/*
	 * do not return u_int64_t's
	 */
	if (s1->id < s2->id)
		return (-1);

	if (s1->id > s2->id)
		return (1);

	return (0);
}

void
lka_clear_aliaseslist(struct aliaseslist *aliaseslist)
{
	struct alias *alias;

	while ((alias = TAILQ_FIRST(aliaseslist)) != NULL) {
		TAILQ_REMOVE(aliaseslist, alias, entry);
		free(alias);
	}
}

int
lka_encode_credentials(char *dst, size_t size, char *user)
{
	char	*pass, *buf;
	int	 buflen;

	if ((pass = strchr(user, ':')) == NULL)
		return 0;
	*pass++ = '\0';

	if ((buflen = asprintf(&buf, "%c%s%c%s", '\0', user, '\0', pass)) == -1)
		fatal(NULL);

	if (kn_encode_base64(buf, buflen, dst, size) == -1) {
		free(buf);
		return 0;
	}

	free(buf);
	return 1;
}

SPLAY_GENERATE(lkatree, lkasession, nodes, lkasession_cmp);