/*      $OpenBSD: dispatcher.c,v 1.7 2022/02/18 16:57:36 millert Exp $  */

/*
 * Copyright (c) 2014 Gilles Chehade <gilles@poolp.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 <pwd.h>
#include <signal.h>
#include <unistd.h>

#include "smtpd.h"
#include "log.h"

void mda_imsg(struct mproc *, struct imsg *);
void mta_imsg(struct mproc *, struct imsg *);
void smtp_imsg(struct mproc *, struct imsg *);

static void dispatcher_shutdown(void);

void
dispatcher_imsg(struct mproc *p, struct imsg *imsg)
{
        struct msg      m;
        int             v;

        if (imsg == NULL)
                dispatcher_shutdown();

        switch (imsg->hdr.type) {

        case IMSG_GETADDRINFO:
        case IMSG_GETADDRINFO_END:
        case IMSG_GETNAMEINFO:
        case IMSG_RES_QUERY:
                resolver_dispatch_result(p, imsg);
                return;

        case IMSG_CONF_START:
                return;
        case IMSG_CONF_END:
                smtp_configure();
                return;
        case IMSG_CTL_VERBOSE:
                m_msg(&m, imsg);
                m_get_int(&m, &v);
                m_end(&m);
                log_trace_verbose(v);
                return;
        case IMSG_CTL_PROFILE:
                m_msg(&m, imsg);
                m_get_int(&m, &v);
                m_end(&m);
                profiling = v;
                return;

        /* smtp imsg */
        case IMSG_SMTP_CHECK_SENDER:
        case IMSG_SMTP_EXPAND_RCPT:
        case IMSG_SMTP_LOOKUP_HELO:
        case IMSG_SMTP_AUTHENTICATE:
        case IMSG_SMTP_MESSAGE_COMMIT:
        case IMSG_SMTP_MESSAGE_CREATE:
        case IMSG_SMTP_MESSAGE_OPEN:
        case IMSG_FILTER_SMTP_PROTOCOL:
        case IMSG_FILTER_SMTP_DATA_BEGIN:
        case IMSG_QUEUE_ENVELOPE_SUBMIT:
        case IMSG_QUEUE_ENVELOPE_COMMIT:
        case IMSG_QUEUE_SMTP_SESSION:
        case IMSG_CTL_SMTP_SESSION:
        case IMSG_CTL_PAUSE_SMTP:
        case IMSG_CTL_RESUME_SMTP:
                smtp_imsg(p, imsg);
                return;

        /* mta imsg */
        case IMSG_QUEUE_TRANSFER:
        case IMSG_MTA_OPEN_MESSAGE:
        case IMSG_MTA_LOOKUP_CREDENTIALS:
        case IMSG_MTA_LOOKUP_SMARTHOST:
        case IMSG_MTA_LOOKUP_SOURCE:
        case IMSG_MTA_LOOKUP_HELO:
        case IMSG_MTA_DNS_HOST:
        case IMSG_MTA_DNS_HOST_END:
        case IMSG_MTA_DNS_MX_PREFERENCE:
        case IMSG_CTL_RESUME_ROUTE:
        case IMSG_CTL_MTA_SHOW_HOSTS:
        case IMSG_CTL_MTA_SHOW_RELAYS:
        case IMSG_CTL_MTA_SHOW_ROUTES:
        case IMSG_CTL_MTA_SHOW_HOSTSTATS:
        case IMSG_CTL_MTA_BLOCK:
        case IMSG_CTL_MTA_UNBLOCK:
        case IMSG_CTL_MTA_SHOW_BLOCK:
                mta_imsg(p, imsg);
                return;

        /* mda imsg */
        case IMSG_MDA_LOOKUP_USERINFO:
        case IMSG_QUEUE_DELIVER:
        case IMSG_MDA_OPEN_MESSAGE:
        case IMSG_MDA_FORK:
        case IMSG_MDA_DONE:
                mda_imsg(p, imsg);
                return;
        default:
                break;
        }

        fatalx("session_imsg: unexpected %s imsg", imsg_to_str(imsg->hdr.type));
}

static void
dispatcher_shutdown(void)
{
        log_debug("debug: dispatcher agent exiting");
        _exit(0);
}

int
dispatcher(void)
{
        struct passwd   *pw;

        ca_engine_init();

        mda_postfork();
        mta_postfork();
        smtp_postfork();

        /* do not purge listeners and pki, they are purged
         * in smtp_configure()
         */
        purge_config(PURGE_TABLES|PURGE_RULES);

        if ((pw = getpwnam(SMTPD_USER)) == NULL)
                fatalx("unknown user " SMTPD_USER);

        if (chroot(PATH_CHROOT) == -1)
                fatal("dispatcher: chroot");
        if (chdir("/") == -1)
                fatal("dispatcher: chdir(\"/\")");

        config_process(PROC_DISPATCHER);

        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("dispatcher: cannot drop privileges");

        imsg_callback = dispatcher_imsg;
        event_init();

        mda_postprivdrop();
        mta_postprivdrop();
        smtp_postprivdrop();

        signal(SIGINT, SIG_IGN);
        signal(SIGTERM, SIG_IGN);
        signal(SIGPIPE, SIG_IGN);
        signal(SIGHUP, SIG_IGN);

        config_peer(PROC_PARENT);
        config_peer(PROC_QUEUE);
        config_peer(PROC_LKA);
        config_peer(PROC_CONTROL);
        config_peer(PROC_CA);

        if (pledge("stdio inet unix recvfd sendfd", NULL) == -1)
                fatal("pledge");

        event_dispatch();
        fatalx("exited event loop");

        return (0);
}