/*
 * Copyright (c) 2011-2012 The DragonFly Project.  All rights reserved.
 *
 * This code is derived from software contributed to The DragonFly Project
 * by Matthew Dillon <dillon@dragonflybsd.org>
 * by Venkatesh Srinivas <vsrinivas@dragonflybsd.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name of The DragonFly Project nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific, prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include "hammer2.h"

#include <sys/xdiskioctl.h>
#include <machine/atomic.h>

struct hammer2_media_config {
        hammer2_volconf_t       copy_run;
        hammer2_volconf_t       copy_pend;
        pthread_t               thread;
        int                     thread_started;
        pthread_cond_t          cond;
        int                     ctl;
        int                     fd;
        int                     pipefd[2];      /* signal stop */
        dmsg_iocom_t            iocom;
        pthread_t               iocom_thread;
        enum { H2MC_STOPPED, H2MC_CONNECT, H2MC_RUNNING } state;
};

typedef struct hammer2_media_config hammer2_media_config_t;

#define H2CONFCTL_STOP          0x00000001
#define H2CONFCTL_UPDATE        0x00000002

struct diskcon {
        TAILQ_ENTRY(diskcon) entry;
        char    *disk;
};

struct service_node_opaque {
        char    cl_label[64];
        char    fs_label[64];
        dmsg_media_block_t block;
        int     attached;
        int     servicing;
        int     servicefd;
};

struct autoconn {
        TAILQ_ENTRY(autoconn) entry;
        char    *host;
        int     stage;
        int     stopme;
        int     pipefd[2];      /* {read,write} */
        enum { AUTOCONN_INACTIVE, AUTOCONN_ACTIVE } state;
        pthread_t thread;
};

#define WS " \r\n"

static TAILQ_HEAD(, diskcon) diskconq = TAILQ_HEAD_INITIALIZER(diskconq);
static pthread_mutex_t diskmtx;
static pthread_mutex_t confmtx;

static void *service_thread(void *data);
static void *udev_thread(void *data);
static void *autoconn_thread(void *data);
static void master_reconnect(const char *mntpt);
static void disk_reconnect(const char *disk);
static void disk_disconnect(void *handle);
static void udev_check_disks(void);
static void hammer2_usrmsg_handler(dmsg_msg_t *msg, int unmanaged);
static void *hammer2_volconf_thread(void *info);
static void hammer2_volconf_signal(dmsg_iocom_t *iocom);
static void hammer2_volconf_start(hammer2_media_config_t *conf,
                        const char *hostname);
static void hammer2_volconf_stop(hammer2_media_config_t *conf);


static void xdisk_connect(void);

/*
 * Start-up the master listener daemon for the machine.  This daemon runs
 * a UDP discovery protocol, a TCP rendezvous, and scans certain files
 * and directories for work.
 *
 * --
 *
 * The only purpose for the UDP discovery protocol is to determine what
 * other IPs on the LAN are running the hammer2 service daemon.  DNS is not
 * required to operate, but hostnames (if assigned) must be unique.  If
 * no hostname is assigned the host's IP is used as the name.  This name
 * is broadcast along with the mtime of the originator's private key.
 *
 * Receiving hammer2 service daemons which are able to match the label against
 * /etc/hammer2/remote/<label>.pub will initiate a persistent connection
 * to the target.  Removal of the file will cause a disconnection.  A failed
 * public key negotiation stops further connection attempts until either the
 * file is updated or the remote mtime is updated.
 *
 * Generally speaking this results in a web of connections, typically a
 * combination of point-to-point for the more important links and relayed
 * (spanning tree) for less important or filtered links.
 *
 * --
 *
 * The TCP listener serves as a rendezvous point in the cluster, accepting
 * connections, performing registrations and authentications, maintaining
 * the spanning tree, and keeping track of message state so disconnects can
 * be handled properly.
 *
 * Once authenticated only low-level messaging protocols (which includes
 * tracking persistent messages) are handled by this daemon.  This daemon
 * does not run the higher level quorum or locking protocols.
 *
 * --
 *
 * The file /etc/hammer2/autoconn, if it exists, contains a list of targets
 * to connect to (which do not have to be on the local lan).  This list will
 * be retried until a connection can be established.  The file is not usually
 * needed for linkages local to the LAN.
 */
int
cmd_service(void)
{
        struct sockaddr_in lsin;
        int on;
        int lfd;

        /*
         * Acquire socket and set options
         */
        if ((lfd = socket(AF_INET, SOCK_STREAM, 0)) < 0) {
                fprintf(stderr, "master_listen: socket(): %s\n",
                        strerror(errno));
                return 1;
        }
        on = 1;
        setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR, &on, sizeof(on));

        /*
         * Setup listen port and try to bind.  If the bind fails we assume
         * that a master listener process is already running and silently
         * fail.
         */
        bzero(&lsin, sizeof(lsin));
        lsin.sin_family = AF_INET;
        lsin.sin_addr.s_addr = INADDR_ANY;
        lsin.sin_port = htons(DMSG_LISTEN_PORT);
        if (bind(lfd, (struct sockaddr *)&lsin, sizeof(lsin)) < 0) {
                close(lfd);
                if (QuietOpt == 0) {
                        fprintf(stderr,
                                "master listen: daemon already running\n");
                }
                return 0;
        }
        if (QuietOpt == 0)
                fprintf(stderr, "master listen: startup\n");
        listen(lfd, 50);

        /*
         * Fork and disconnect the controlling terminal and parent process,
         * executing the specified function as a pthread.
         *
         * Returns to the original process which can then continue running.
         * In debug mode this call will create the pthread without forking
         * and set NormalExit to 0, instead of fork.
         */
        hammer2_demon(service_thread, (void *)(intptr_t)lfd);
        if (NormalExit)
                close(lfd);
        return 0;
}

/*
 * Master listen/accept thread.  Accept connections on the master socket,
 * starting a pthread for each one.
 */
static
void *
service_thread(void *data)
{
        struct sockaddr_in asin;
        socklen_t alen;
        pthread_t thread;
        dmsg_master_service_info_t *info;
        int lfd = (int)(intptr_t)data;
        int fd;
        int i;
        int count;
        int opt;
        struct statfs *mntbuf = NULL;
        struct statvfs *mntvbuf = NULL;

        /*
         * Nobody waits for us
         */
        setproctitle("hammer2 master listen");
        pthread_detach(pthread_self());

        /*
         * Start up a thread to handle block device monitoring for
         * export to the cluster.
         */
        pthread_create(&thread, NULL, udev_thread, NULL);

        /*
         * Start up a thread to tie /dev/xdisk into the cluster
         * controller.
         */
        xdisk_connect();

        /*
         * Start thread to manage /etc/hammer2/autoconn
         */
        pthread_create(&thread, NULL, autoconn_thread, NULL);

        /*
         * Scan existing hammer2 mounts and reconnect to them using
         * HAMMER2IOC_RECLUSTER.
         */
        count = getmntvinfo(&mntbuf, &mntvbuf, MNT_NOWAIT);
        for (i = 0; i < count; ++i) {
                if (strcmp(mntbuf[i].f_fstypename, "hammer2") == 0)
                        master_reconnect(mntbuf[i].f_mntonname);
        }

        /*
         * Accept connections and create pthreads to handle them after
         * validating the IP.
         */
        for (;;) {
                alen = sizeof(asin);
                fd = accept(lfd, (struct sockaddr *)&asin, &alen);
                if (fd < 0) {
                        if (errno == EINTR)
                                continue;
                        break;
                }
                opt = 1;
                setsockopt(fd, IPPROTO_TCP, TCP_NODELAY, &opt, sizeof opt);
                fprintf(stderr, "service_thread: accept fd %d\n", fd);
                info = malloc(sizeof(*info));
                bzero(info, sizeof(*info));
                info->fd = fd;
                info->detachme = 1;
                info->usrmsg_callback = hammer2_usrmsg_handler;
                info->label = strdup("client");
                pthread_create(&thread, NULL, dmsg_master_service, info);
        }
        return (NULL);
}

/*
 * Handle/Monitor the dmsg stream.  If unmanaged is set we are responsible
 * for responding for the message, otherwise if it is not set libdmsg has
 * already done some preprocessing and will respond to the message for us
 * when we return.
 *
 * We primarily monitor for VOLCONFs
 */
static
void
hammer2_usrmsg_handler(dmsg_msg_t *msg, int unmanaged)
{
        dmsg_state_t *state;
        hammer2_media_config_t *conf;
        dmsg_lnk_hammer2_volconf_t *msgconf;
        int i;

        /*
         * Only process messages which are part of a LNK_CONN stream
         */
        state = msg->state;
        if (state == NULL ||
            (state->rxcmd & DMSGF_BASECMDMASK) != DMSG_LNK_CONN) {
                hammer2_shell_parse(msg, unmanaged);
                return;
        }

        switch(msg->tcmd) {
        case DMSG_LNK_CONN | DMSGF_CREATE | DMSGF_DELETE:
        case DMSG_LNK_CONN | DMSGF_DELETE:
        case DMSG_LNK_ERROR | DMSGF_DELETE:
                /*
                 * Deleting connection, clean out all volume configs
                 */
                if (state->media == NULL || state->media->usrhandle == NULL)
                        break;
                conf = state->media->usrhandle;
                fprintf(stderr, "Shutting down media spans\n");
                for (i = 0; i < HAMMER2_COPYID_COUNT; ++i) {
                        if (conf[i].thread) {
                                conf[i].ctl = H2CONFCTL_STOP;
                                pthread_cond_signal(&conf[i].cond);
                        }
                }
                for (i = 0; i < HAMMER2_COPYID_COUNT; ++i) {
                        if (conf[i].thread) {
                                pthread_join(conf[i].thread, NULL);
                                conf->thread_started = 0;
                                pthread_cond_destroy(&conf[i].cond);
                        }
                }
                state->media->usrhandle = NULL;
                free(conf);
                break;
        case DMSG_LNK_HAMMER2_VOLCONF:
                /*
                 * One-way volume-configuration message is transmitted
                 * over the open LNK_CONN transaction.
                 */
                fprintf(stderr, "RECEIVED VOLCONF\n");

                if ((conf = state->media->usrhandle) == NULL) {
                        conf = malloc(sizeof(*conf) * HAMMER2_COPYID_COUNT);
                        bzero(conf, sizeof(*conf) * HAMMER2_COPYID_COUNT);
                        state->media->usrhandle = conf;
                }
                msgconf = H2_LNK_VOLCONF(msg);

                if (msgconf->index < 0 ||
                    msgconf->index >= HAMMER2_COPYID_COUNT) {
                        fprintf(stderr,
                                "VOLCONF: ILLEGAL INDEX %d\n",
                                msgconf->index);
                        break;
                }
                if (msgconf->copy.path[sizeof(msgconf->copy.path) - 1] != 0 ||
                    msgconf->copy.path[0] == 0) {
                        fprintf(stderr,
                                "VOLCONF: ILLEGAL PATH %d\n",
                                msgconf->index);
                        break;
                }
                conf += msgconf->index;
                pthread_mutex_lock(&confmtx);
                conf->copy_pend = msgconf->copy;
                conf->ctl |= H2CONFCTL_UPDATE;
                pthread_mutex_unlock(&confmtx);
                if (conf->thread_started == 0) {
                        fprintf(stderr, "VOLCONF THREAD STARTED\n");
                        pthread_cond_init(&conf->cond, NULL);
                        pthread_create(&conf->thread, NULL,
                                       hammer2_volconf_thread, (void *)conf);
                        conf->thread_started = 1;
                }
                pthread_cond_signal(&conf->cond);
                break;
        default:
                if (unmanaged)
                        dmsg_msg_reply(msg, DMSG_ERR_NOSUPP);
                break;
        }
}

static void *
hammer2_volconf_thread(void *info)
{
        hammer2_media_config_t *conf = info;

        setproctitle("hammer2 volconf");

        pthread_mutex_lock(&confmtx);
        while ((conf->ctl & H2CONFCTL_STOP) == 0) {
                if (conf->ctl & H2CONFCTL_UPDATE) {
                        fprintf(stderr, "VOLCONF UPDATE\n");
                        conf->ctl &= ~H2CONFCTL_UPDATE;
                        if (bcmp(&conf->copy_run, &conf->copy_pend,
                                 sizeof(conf->copy_run)) == 0) {
                                fprintf(stderr, "VOLCONF: no changes\n");
                                continue;
                        }
                        /*
                         * XXX TODO - auto reconnect on lookup failure or
                         *              connect failure or stream failure.
                         */

                        pthread_mutex_unlock(&confmtx);
                        hammer2_volconf_stop(conf);
                        conf->copy_run = conf->copy_pend;
                        if (conf->copy_run.copyid != 0 &&
                            strncmp((char*)conf->copy_run.path, "span:", 5) == 0) {
                                hammer2_volconf_start(conf,
                                                      (char*)conf->copy_run.path + 5);
                        }
                        pthread_mutex_lock(&confmtx);
                        fprintf(stderr, "VOLCONF UPDATE DONE state %d\n", conf->state);
                }
                if (conf->state == H2MC_CONNECT) {
                        hammer2_volconf_start(conf, (char*)conf->copy_run.path + 5);
                        pthread_mutex_unlock(&confmtx);
                        sleep(5);
                        pthread_mutex_lock(&confmtx);
                } else {
                        pthread_cond_wait(&conf->cond, &confmtx);
                }
        }
        pthread_mutex_unlock(&confmtx);
        hammer2_volconf_stop(conf);
        return(NULL);
}

static
void
hammer2_volconf_start(hammer2_media_config_t *conf, const char *hostname)
{
        dmsg_master_service_info_t *info;

        switch(conf->state) {
        case H2MC_STOPPED:
        case H2MC_CONNECT:
                conf->fd = dmsg_connect(hostname);
                if (conf->fd < 0) {
                        fprintf(stderr, "Unable to connect to %s\n", hostname);
                        conf->state = H2MC_CONNECT;
                } else if (pipe(conf->pipefd) < 0) {
                        close(conf->fd);
                        fprintf(stderr, "pipe() failed during volconf\n");
                        conf->state = H2MC_CONNECT;
                } else {
                        fprintf(stderr, "VOLCONF CONNECT\n");
                        info = malloc(sizeof(*info));
                        bzero(info, sizeof(*info));
                        info->fd = conf->fd;
                        info->altfd = conf->pipefd[0];
                        info->altmsg_callback = hammer2_volconf_signal;
                        info->usrmsg_callback = hammer2_usrmsg_handler;
                        info->detachme = 0;
                        conf->state = H2MC_RUNNING;
                        pthread_create(&conf->iocom_thread, NULL,
                                       dmsg_master_service, info);
                }
                break;
        case H2MC_RUNNING:
                break;
        }
}

static
void
hammer2_volconf_stop(hammer2_media_config_t *conf)
{
        switch(conf->state) {
        case H2MC_STOPPED:
                break;
        case H2MC_CONNECT:
                conf->state = H2MC_STOPPED;
                break;
        case H2MC_RUNNING:
                close(conf->pipefd[1]);
                conf->pipefd[1] = -1;
                pthread_join(conf->iocom_thread, NULL);
                conf->state = H2MC_STOPPED;
                break;
        }
}

static
void
hammer2_volconf_signal(dmsg_iocom_t *iocom)
{
        atomic_set_int(&iocom->flags, DMSG_IOCOMF_EOF);
}

/*
 * Monitor block devices.  Currently polls every ~10 seconds or so.
 */
static
void *
udev_thread(void *data __unused)
{
        int     fd;
        int     seq = 0;

        pthread_detach(pthread_self());
        setproctitle("hammer2 udev_thread");

        if ((fd = open(UDEV_DEVICE_PATH, O_RDWR)) < 0) {
                fprintf(stderr, "udev_thread: unable to open \"%s\"\n",
                        UDEV_DEVICE_PATH);
                pthread_exit(NULL);
        }
        udev_check_disks();
        while (ioctl(fd, UDEVWAIT, &seq) == 0) {
                udev_check_disks();
                sleep(1);
        }
        return (NULL);
}

static void *autoconn_connect_thread(void *data);
static void autoconn_disconnect_signal(dmsg_iocom_t *iocom);

static
void *
autoconn_thread(void *data __unused)
{
        TAILQ_HEAD(, autoconn) autolist;
        struct autoconn *ac;
        struct autoconn *next;
        pthread_t thread;
        struct stat st;
        time_t  t;
        time_t  lmod;
        int     found_last;
        FILE    *fp;
        char    buf[256];

        TAILQ_INIT(&autolist);
        found_last = 0;
        lmod = 0;

        pthread_detach(pthread_self());
        setproctitle("hammer2 autoconn_thread");
        for (;;) {
                /*
                 * Polling interval
                 */
                sleep(5);

                /*
                 * Poll the file.  Loop up if the synchronized state (lmod)
                 * has not changed.
                 */
                if (stat(HAMMER2_DEFAULT_DIR "/autoconn", &st) == 0) {
                        if (lmod == st.st_mtime)
                                continue;
                        fp = fopen(HAMMER2_DEFAULT_DIR "/autoconn", "r");
                        if (fp == NULL)
                                continue;
                } else {
                        if (lmod == 0)
                                continue;
                        fp = NULL;
                }

                /*
                 * Wait at least 5 seconds after the file is created or
                 * removed.
                 *
                 * Do not update the synchronized state.
                 */
                if (fp == NULL && found_last) {
                        found_last = 0;
                        continue;
                } else if (fp && found_last == 0) {
                        fclose(fp);
                        found_last = 1;
                        continue;
                }

                /*
                 * Don't scan the file until the time progresses past the
                 * file's mtime, so we can validate that the file was not
                 * further modified during our scan.
                 *
                 * Do not update the synchronized state.
                 */
                time(&t);
                if (fp) {
                        if (t == st.st_mtime) {
                                fclose(fp);
                                continue;
                        }
                        t = st.st_mtime;
                } else {
                        t = 0;
                }

                /*
                 * Set staging to disconnect, then scan the file.
                 */
                TAILQ_FOREACH(ac, &autolist, entry)
                        ac->stage = 0;
                while (fp && fgets(buf, sizeof(buf), fp) != NULL) {
                        char *host;

                        if ((host = strtok(buf, " \t\r\n")) == NULL ||
                            host[0] == '#') {
                                continue;
                        }
                        TAILQ_FOREACH(ac, &autolist, entry) {
                                if (strcmp(host, ac->host) == 0)
                                        break;
                        }
                        if (ac == NULL) {
                                ac = malloc(sizeof(*ac));
                                bzero(ac, sizeof(*ac));
                                ac->host = strdup(host);
                                ac->state = AUTOCONN_INACTIVE;
                                TAILQ_INSERT_TAIL(&autolist, ac, entry);
                        }
                        ac->stage = 1;
                }

                /*
                 * Ignore the scan (and retry again) if the file was
                 * modified during the scan.
                 *
                 * Do not update the synchronized state.
                 */
                if (fp) {
                        if (fstat(fileno(fp), &st) < 0) {
                                fclose(fp);
                                continue;
                        }
                        fclose(fp);
                        if (t != st.st_mtime)
                                continue;
                }

                /*
                 * Update the synchronized state and reconfigure the
                 * connect list as needed.
                 */
                lmod = t;
                next = TAILQ_FIRST(&autolist);
                while ((ac = next) != NULL) {
                        next = TAILQ_NEXT(ac, entry);

                        /*
                         * Staging, initiate
                         */
                        if (ac->stage && ac->state == AUTOCONN_INACTIVE) {
                                if (pipe(ac->pipefd) == 0) {
                                        ac->stopme = 0;
                                        ac->state = AUTOCONN_ACTIVE;
                                        pthread_create(&thread, NULL,
                                                       autoconn_connect_thread,
                                                       ac);
                                }
                        }

                        /*
                         * Unstaging, stop active connection.
                         *
                         * We write to the pipe which causes the iocom_core
                         * to call autoconn_disconnect_signal().
                         */
                        if (ac->stage == 0 &&
                            ac->state == AUTOCONN_ACTIVE) {
                                if (ac->stopme == 0) {
                                        char dummy = 0;
                                        ac->stopme = 1;
                                        write(ac->pipefd[1], &dummy, 1);
                                }
                        }

                        /*
                         * Unstaging, delete inactive connection.
                         */
                        if (ac->stage == 0 &&
                            ac->state == AUTOCONN_INACTIVE) {
                                TAILQ_REMOVE(&autolist, ac, entry);
                                free(ac->host);
                                free(ac);
                                continue;
                        }
                }
                sleep(5);
        }
        return(NULL);
}

static
void *
autoconn_connect_thread(void *data)
{
        dmsg_master_service_info_t *info;
        struct autoconn *ac;
        void *res;
        int fd;

        ac = data;
        pthread_detach(pthread_self());
        setproctitle("hammer2 dmsg");

        while (ac->stopme == 0) {
                fd = dmsg_connect(ac->host);
                if (fd < 0) {
                        if (DMsgDebugOpt > 2) {
                                fprintf(stderr,
                                        "autoconn: Connect failure: %s\n",
                                        ac->host);
                        }
                        sleep(5);
                        continue;
                }
                fprintf(stderr, "autoconn: Connect %s\n", ac->host);

                info = malloc(sizeof(*info));
                bzero(info, sizeof(*info));
                info->fd = fd;
                info->altfd = ac->pipefd[0];
                info->altmsg_callback = autoconn_disconnect_signal;
                info->usrmsg_callback = hammer2_usrmsg_handler;
                info->detachme = 0;
                info->noclosealt = 1;
                pthread_create(&ac->thread, NULL, dmsg_master_service, info);
                pthread_join(ac->thread, &res);
        }
        close(ac->pipefd[0]);
        ac->state = AUTOCONN_INACTIVE;
        /* auto structure can be ripped out here */
        return(NULL);
}

static
void
autoconn_disconnect_signal(dmsg_iocom_t *iocom)
{
        fprintf(stderr, "autoconn: Shutting down socket\n");
        atomic_set_int(&iocom->flags, DMSG_IOCOMF_EOF);
}

/*
 * Retrieve the list of disk attachments and attempt to export
 * them.
 */
static
void
udev_check_disks(void)
{
        char tmpbuf[1024];
        char *buf = NULL;
        char *disk;
        int error;
        size_t n;

        for (;;) {
                n = 0;
                error = sysctlbyname("kern.disks", NULL, &n, NULL, 0);
                if (error < 0 || n == 0)
                        break;
                if (n >= sizeof(tmpbuf))
                        buf = malloc(n + 1);
                else
                        buf = tmpbuf;
                error = sysctlbyname("kern.disks", buf, &n, NULL, 0);
                if (error == 0) {
                        buf[n] = 0;
                        break;
                }
                if (buf != tmpbuf) {
                        free(buf);
                        buf = NULL;
                }
                if (errno != ENOMEM)
                        break;
        }
        if (buf) {
                fprintf(stderr, "DISKS: %s\n", buf);
                for (disk = strtok(buf, WS); disk; disk = strtok(NULL, WS)) {
                        disk_reconnect(disk);
                }
                if (buf != tmpbuf)
                        free(buf);
        }
}

/*
 * Normally the mount program supplies a cluster communications
 * descriptor to the hammer2 vfs on mount, but if you kill the service
 * daemon and restart it that link will be lost.
 *
 * This procedure attempts to [re]connect to existing mounts when
 * the service daemon is started up before going into its accept
 * loop.
 *
 * NOTE: A hammer2 mount point can only accomodate one connection at a time
 *       so this will disconnect any existing connection during the
 *       reconnect.
 */
static
void
master_reconnect(const char *mntpt)
{
        struct hammer2_ioc_recluster recls;
        dmsg_master_service_info_t *info;
        pthread_t thread;
        int fd;
        int pipefds[2];

        fd = open(mntpt, O_RDONLY);
        if (fd < 0) {
                fprintf(stderr, "reconnect %s: no access to mount\n", mntpt);
                return;
        }
        if (pipe(pipefds) < 0) {
                fprintf(stderr, "reconnect %s: pipe() failed\n", mntpt);
                close(fd);
                return;
        }
        bzero(&recls, sizeof(recls));
        recls.fd = pipefds[0];
        if (ioctl(fd, HAMMER2IOC_RECLUSTER, &recls) < 0) {
                fprintf(stderr, "reconnect %s: ioctl failed\n", mntpt);
                close(pipefds[0]);
                close(pipefds[1]);
                close(fd);
                return;
        }
        close(pipefds[0]);
        close(fd);

        info = malloc(sizeof(*info));
        bzero(info, sizeof(*info));
        info->fd = pipefds[1];
        info->detachme = 1;
        info->usrmsg_callback = hammer2_usrmsg_handler;
        info->label = strdup("hammer2");
        pthread_create(&thread, NULL, dmsg_master_service, info);
}

/*
 * Reconnect a physical disk service to the mesh.
 */
static
void
disk_reconnect(const char *disk)
{
        struct disk_ioc_recluster recls;
        struct diskcon *dc;
        dmsg_master_service_info_t *info;
        pthread_t thread;
        int fd;
        int pipefds[2];
        char *path;

        /*
         * Urm, this will auto-create mdX+1, just ignore for now.
         * This mechanic needs to be fixed.  It might actually be nice
         * to be able to export md disks.
         */
        if (strncmp(disk, "md", 2) == 0)
                return;
        if (strncmp(disk, "xa", 2) == 0)
                return;

        /*
         * Check if already connected
         */
        pthread_mutex_lock(&diskmtx);
        TAILQ_FOREACH(dc, &diskconq, entry) {
                if (strcmp(dc->disk, disk) == 0)
                        break;
        }
        pthread_mutex_unlock(&diskmtx);
        if (dc)
                return;

        /*
         * Not already connected, create a connection to the kernel
         * disk driver.
         */
        asprintf(&path, "/dev/%s", disk);
        fd = open(path, O_RDONLY);
        if (fd < 0) {
                fprintf(stderr, "reconnect %s: no access to disk\n", disk);
                free(path);
                return;
        }
        free(path);
        if (pipe(pipefds) < 0) {
                fprintf(stderr, "reconnect %s: pipe() failed\n", disk);
                close(fd);
                return;
        }
        bzero(&recls, sizeof(recls));
        recls.fd = pipefds[0];
        if (ioctl(fd, DIOCRECLUSTER, &recls) < 0) {
                fprintf(stderr, "reconnect %s: ioctl failed\n", disk);
                close(pipefds[0]);
                close(pipefds[1]);
                close(fd);
                return;
        }
        close(pipefds[0]);
        close(fd);

        dc = malloc(sizeof(*dc));
        dc->disk = strdup(disk);
        pthread_mutex_lock(&diskmtx);
        TAILQ_INSERT_TAIL(&diskconq, dc, entry);
        pthread_mutex_unlock(&diskmtx);

        info = malloc(sizeof(*info));
        bzero(info, sizeof(*info));
        info->fd = pipefds[1];
        info->detachme = 1;
        info->usrmsg_callback = hammer2_usrmsg_handler;
        info->exit_callback = disk_disconnect;
        info->handle = dc;
        info->label = strdup(dc->disk);
        pthread_create(&thread, NULL, dmsg_master_service, info);
}

static
void
disk_disconnect(void *handle)
{
        struct diskcon *dc = handle;

        fprintf(stderr, "DISK_DISCONNECT %s\n", dc->disk);

        pthread_mutex_lock(&diskmtx);
        TAILQ_REMOVE(&diskconq, dc, entry);
        pthread_mutex_unlock(&diskmtx);
        free(dc->disk);
        free(dc);
}

/*
 * Connect our cluster controller to /dev/xdisk.  xdisk will pick up
 * SPAN messages that we route to it, makes remote block devices
 * available to the host, and can issue dmsg transactions based on
 * device requests.
 */
static
void
xdisk_connect(void)
{
        dmsg_master_service_info_t *info;
        struct xdisk_attach_ioctl xaioc;
        pthread_t thread;
        int pipefds[2];
        int xfd;
        int error;

        /*
         * Is /dev/xdisk available?
         */
        xfd = open("/dev/xdisk", O_RDWR, 0600);
        if (xfd < 0) {
                fprintf(stderr, "xdisk_connect: Unable to open /dev/xdisk\n");
                return;
        }

        if (pipe(pipefds) < 0) {
                fprintf(stderr, "xdisk_connect: pipe() failed\n");
                return;
        }

        /*
         * Pipe between cluster controller (this user process).
         */
        info = malloc(sizeof(*info));
        bzero(info, sizeof(*info));
        info->fd = pipefds[1];
        info->detachme = 1;
        info->usrmsg_callback = hammer2_usrmsg_handler;
        info->exit_callback = NULL;
        pthread_create(&thread, NULL, dmsg_master_service, info);

        /*
         * And the xdisk device.
         */
        bzero(&xaioc, sizeof(xaioc));
        xaioc.fd = pipefds[0];
        error = ioctl(xfd, XDISKIOCATTACH, &xaioc);
        close(pipefds[0]);
        close(xfd);

        if (error < 0) {
                fprintf(stderr,
                        "xdisk_connect: cannot attach %s\n",
                        strerror(errno));
                return;
        }
}

/*
 * Execute the specified function as a detached independent process/daemon,
 * unless we are in debug mode.  If we are in debug mode the function is
 * executed as a pthread in the current process.
 */
void
hammer2_demon(void *(*func)(void *), void *arg)
{
        pthread_t thread;
        pid_t pid;
        int ttyfd;

        /*
         * Do not disconnect in debug mode
         */
        if (DebugOpt) {
                pthread_create(&thread, NULL, func, arg);
                NormalExit = 0;
                return;
        }

        /*
         * Otherwise disconnect us.  Double-fork to get rid of the ppid
         * association and disconnect the TTY.
         */
        if ((pid = fork()) < 0) {
                fprintf(stderr, "hammer2: fork(): %s\n", strerror(errno));
                exit(1);
        }
        if (pid > 0) {
                while (waitpid(pid, NULL, 0) != pid)
                        ;
                return;         /* parent returns */
        }

        /*
         * Get rid of the TTY/session before double-forking to finish off
         * the ppid.
         */
        ttyfd = open("/dev/null", O_RDWR);
        if (ttyfd >= 0) {
                if (ttyfd != 0)
                        dup2(ttyfd, 0);
                if (ttyfd != 1)
                        dup2(ttyfd, 1);
                if (ttyfd != 2)
                        dup2(ttyfd, 2);
                if (ttyfd > 2)
                        close(ttyfd);
        }

        ttyfd = open("/dev/tty", O_RDWR);
        if (ttyfd >= 0) {
                ioctl(ttyfd, TIOCNOTTY, 0);
                close(ttyfd);
        }
        setsid();

        /*
         * Second fork to disconnect ppid (the original parent waits for
         * us to exit).
         */
        if ((pid = fork()) < 0) {
                _exit(2);
        }
        if (pid > 0)
                _exit(0);

        /*
         * The double child
         */
        setsid();
        pthread_create(&thread, NULL, func, arg);
        pthread_exit(NULL);
        _exit(2);       /* NOT REACHED */
}