/*      $OpenBSD: control.c,v 1.18 2023/03/08 04:43:13 guenther Exp $   */

/*
 * Copyright (c) 2010 Martin Hedenfalk <martin@bzero.se>
 * Copyright (c) 2003, 2004 Henning Brauer <henning@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/queue.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/tree.h>

#include <net/if.h>

#include <errno.h>
#include <event.h>
#include <fcntl.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>

#include "ldapd.h"
#include "log.h"

#define CONTROL_BACKLOG 5

struct ctl_connlist ctl_conns = TAILQ_HEAD_INITIALIZER(ctl_conns);

struct ctl_conn *control_connbyfd(int);
void             control_close(int, struct control_sock *);
static void      control_imsgev(struct imsgev *iev, int code, struct imsg *imsg);
static void      control_needfd(struct imsgev *iev);

void
control_init(struct control_sock *cs)
{
        struct sockaddr_un       sun;
        int                      fd;
        mode_t                   old_umask, mode;

        if (cs->cs_name == NULL)
                return;

        if ((fd = socket(AF_UNIX, SOCK_STREAM | SOCK_NONBLOCK, 0)) == -1)
                fatal("control_init: socket");

        memset(&sun, 0, sizeof(sun));
        sun.sun_family = AF_UNIX;
        if (strlcpy(sun.sun_path, cs->cs_name,
            sizeof(sun.sun_path)) >= sizeof(sun.sun_path))
                fatalx("control_init: name too long");

        if (connect(fd, (struct sockaddr *)&sun, sizeof(sun)) == 0)
                fatalx("control socket already listening");

        if (unlink(cs->cs_name) == -1 && errno != ENOENT)
                fatal("control_init: unlink");

        if (cs->cs_restricted) {
                old_umask = umask(S_IXUSR|S_IXGRP|S_IXOTH);
                mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH;
        } else {
                old_umask = umask(S_IXUSR|S_IXGRP|S_IWOTH|S_IROTH|S_IXOTH);
                mode = S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP;
        }

        if (bind(fd, (struct sockaddr *)&sun, sizeof(sun)) == -1) {
                (void)umask(old_umask);
                fatal("control_init: bind");
        }
        (void)umask(old_umask);

        if (chmod(cs->cs_name, mode) == -1) {
                (void)unlink(cs->cs_name);
                fatal("control_init: chmod");
        }

        cs->cs_fd = fd;
}

void
control_listen(struct control_sock *cs)
{
        if (cs->cs_name == NULL)
                return;

        if (listen(cs->cs_fd, CONTROL_BACKLOG) == -1)
                fatal("control_listen: listen");

        event_set(&cs->cs_ev, cs->cs_fd, EV_READ,
            control_accept, cs);
        event_add(&cs->cs_ev, NULL);
        evtimer_set(&cs->cs_evt, control_accept, cs);
}

void
control_cleanup(struct control_sock *cs)
{
        if (cs->cs_name == NULL)
                return;
        event_del(&cs->cs_ev);
        event_del(&cs->cs_evt);
}

void
control_accept(int listenfd, short event, void *arg)
{
        struct control_sock     *cs = arg;
        int                      connfd;
        socklen_t                len;
        struct sockaddr_un       sun;
        struct ctl_conn         *c;

        event_add(&cs->cs_ev, NULL);
        if ((event & EV_TIMEOUT))
                return;

        len = sizeof(sun);
        if ((connfd = accept_reserve(listenfd,
            (struct sockaddr *)&sun, &len, FD_RESERVE)) == -1) {
                /*
                 * Pause accept if we are out of file descriptors, or
                 * libevent will haunt us here too.
                 */
                if (errno == ENFILE || errno == EMFILE) {
                        struct timeval evtpause = { 1, 0 };

                        event_del(&cs->cs_ev);
                        evtimer_add(&cs->cs_evt, &evtpause);
                } else if (errno != EWOULDBLOCK && errno != EINTR)
                        log_warn("control_accept");
                return;
        }

        if ((c = calloc(1, sizeof(*c))) == NULL) {
                log_warn("control_accept");
                close(connfd);
                return;
        }

        log_debug("accepted control fd %d", connfd);
        TAILQ_INSERT_TAIL(&ctl_conns, c, entry);
        imsgev_init(&c->iev, connfd, cs, control_imsgev, control_needfd);
}

struct ctl_conn *
control_connbyfd(int fd)
{
        struct ctl_conn *c;

        TAILQ_FOREACH(c, &ctl_conns, entry) {
                if (c->iev.ibuf.fd == fd)
                        break;
        }

        return (c);
}

void
control_close(int fd, struct control_sock *cs)
{
        struct ctl_conn *c;

        if ((c = control_connbyfd(fd)) == NULL) {
                log_warnx("control_close: fd %d: not found", fd);
                return;
        }

        log_debug("close control fd %d", c->iev.ibuf.fd);
        TAILQ_REMOVE(&ctl_conns, c, entry);
        imsgev_clear(&c->iev);

        /* Some file descriptors are available again. */
        if (evtimer_pending(&cs->cs_evt, NULL)) {
                evtimer_del(&cs->cs_evt);
                event_add(&cs->cs_ev, NULL);
        }

        free(c);
}

static int
send_stats(struct imsgev *iev)
{
        struct namespace        *ns;
        const struct btree_stat *st;
        struct ns_stat           nss;

        imsgev_compose(iev, IMSG_CTL_STATS, 0, iev->ibuf.pid, -1,
            &stats, sizeof(stats));

        TAILQ_FOREACH(ns, &conf->namespaces, next) {
                if (namespace_has_referrals(ns))
                        continue;
                memset(&nss, 0, sizeof(nss));
                strlcpy(nss.suffix, ns->suffix, sizeof(nss.suffix));
                if ((st = btree_stat(ns->data_db)) != NULL)
                        bcopy(st, &nss.data_stat, sizeof(nss.data_stat));

                if ((st = btree_stat(ns->indx_db)) != NULL)
                        bcopy(st, &nss.indx_stat, sizeof(nss.indx_stat));

                imsgev_compose(iev, IMSG_CTL_NSSTATS, 0, iev->ibuf.pid, -1,
                    &nss, sizeof(nss));
        }

        imsgev_compose(iev, IMSG_CTL_END, 0, iev->ibuf.pid, -1, NULL, 0);

        return 0;
}

static void
control_imsgev(struct imsgev *iev, int code, struct imsg *imsg)
{
        struct control_sock     *cs;
        struct ctl_conn         *c;
        int                      fd, verbose;

        cs = iev->data;
        fd = iev->ibuf.fd;

        if ((c = control_connbyfd(fd)) == NULL) {
                log_warnx("%s: fd %d: not found", __func__, fd);
                return;
        }

        if (code != IMSGEV_IMSG) {
                control_close(fd, cs);
                return;
        }

        log_debug("%s: got imsg %d on fd %d", __func__, imsg->hdr.type, fd);
        switch (imsg->hdr.type) {
        case IMSG_CTL_STATS:
                if (send_stats(iev) == -1) {
                        log_debug("%s: failed to send statistics", __func__);
                        control_close(fd, cs);
                }
                break;
        case IMSG_CTL_LOG_VERBOSE:
                if (imsg->hdr.len != IMSG_HEADER_SIZE + sizeof(verbose))
                        break;

                bcopy(imsg->data, &verbose, sizeof(verbose));
                imsgev_compose(iev_ldapd, IMSG_CTL_LOG_VERBOSE, 0, 0, -1,
                    &verbose, sizeof(verbose));

                log_setverbose(verbose);
                break;
        default:
                log_warnx("%s: unexpected imsg %d", __func__, imsg->hdr.type);
                break;
        }
}

void
control_needfd(struct imsgev *iev)
{
        fatal("should never need an fd for control messages");
}

int
control_close_any(struct control_sock *cs)
{
        struct ctl_conn         *c;

        c = TAILQ_FIRST(&ctl_conns);
        if (c != NULL) {
                log_warn("closing oldest control connection");
                control_close(c->iev.ibuf.fd, cs);
                return (0);
        }
        log_warn("no control connections to close");
        return (-1);
}