/*-
 * SPDX-License-Identifier: BSD-2-Clause
 *
 * Copyright (c) 2009-2010 The FreeBSD Foundation
 *
 * This software was developed by Pawel Jakub Dawidek under sponsorship from
 * the FreeBSD Foundation.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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 <sys/types.h>
#include <sys/wait.h>

#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "hast.h"
#include "hastd.h"
#include "hast_checksum.h"
#include "hast_compression.h"
#include "hast_proto.h"
#include "hooks.h"
#include "nv.h"
#include "pjdlog.h"
#include "proto.h"
#include "subr.h"

#include "control.h"

void
child_cleanup(struct hast_resource *res)
{

        proto_close(res->hr_ctrl);
        res->hr_ctrl = NULL;
        if (res->hr_event != NULL) {
                proto_close(res->hr_event);
                res->hr_event = NULL;
        }
        if (res->hr_conn != NULL) {
                proto_close(res->hr_conn);
                res->hr_conn = NULL;
        }
        res->hr_workerpid = 0;
}

static void
control_set_role_common(struct hastd_config *cfg, struct nv *nvout,
    uint8_t role, struct hast_resource *res, const char *name, unsigned int no)
{
        int oldrole;

        /* Name is always needed. */
        if (name != NULL)
                nv_add_string(nvout, name, "resource%u", no);

        if (res == NULL) {
                PJDLOG_ASSERT(cfg != NULL);
                PJDLOG_ASSERT(name != NULL);

                TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
                        if (strcmp(res->hr_name, name) == 0)
                                break;
                }
                if (res == NULL) {
                        nv_add_int16(nvout, EHAST_NOENTRY, "error%u", no);
                        return;
                }
        }
        PJDLOG_ASSERT(res != NULL);

        /* Send previous role back. */
        nv_add_string(nvout, role2str(res->hr_role), "role%u", no);

        /* Nothing changed, return here. */
        if (role == res->hr_role)
                return;

        pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role));
        pjdlog_info("Role changed to %s.", role2str(role));

        /* Change role to the new one. */
        oldrole = res->hr_role;
        res->hr_role = role;
        pjdlog_prefix_set("[%s] (%s) ", res->hr_name, role2str(res->hr_role));

        /*
         * If previous role was primary or secondary we have to kill process
         * doing that work.
         */
        if (res->hr_workerpid != 0) {
                if (kill(res->hr_workerpid, SIGTERM) == -1) {
                        pjdlog_errno(LOG_WARNING,
                            "Unable to kill worker process %u",
                            (unsigned int)res->hr_workerpid);
                } else if (waitpid(res->hr_workerpid, NULL, 0) !=
                    res->hr_workerpid) {
                        pjdlog_errno(LOG_WARNING,
                            "Error while waiting for worker process %u",
                            (unsigned int)res->hr_workerpid);
                } else {
                        pjdlog_debug(1, "Worker process %u stopped.",
                            (unsigned int)res->hr_workerpid);
                }
                child_cleanup(res);
        }

        /* Start worker process if we are changing to primary. */
        if (role == HAST_ROLE_PRIMARY)
                hastd_primary(res);
        pjdlog_prefix_set("%s", "");
        hook_exec(res->hr_exec, "role", res->hr_name, role2str(oldrole),
            role2str(res->hr_role), NULL);
}

void
control_set_role(struct hast_resource *res, uint8_t role)
{

        control_set_role_common(NULL, NULL, role, res, NULL, 0);
}

static void
control_status_worker(struct hast_resource *res, struct nv *nvout,
    unsigned int no)
{
        struct nv *cnvin, *cnvout;
        const char *str;
        int error;

        cnvin = NULL;

        /*
         * Prepare and send command to worker process.
         */
        cnvout = nv_alloc();
        nv_add_uint8(cnvout, CONTROL_STATUS, "cmd");
        error = nv_error(cnvout);
        if (error != 0) {
                pjdlog_common(LOG_ERR, 0, error,
                    "Unable to prepare control header");
                goto end;
        }
        if (hast_proto_send(res, res->hr_ctrl, cnvout, NULL, 0) == -1) {
                error = errno;
                pjdlog_errno(LOG_ERR, "Unable to send control header");
                goto end;
        }

        /*
         * Receive response.
         */
        if (hast_proto_recv_hdr(res->hr_ctrl, &cnvin) == -1) {
                error = errno;
                pjdlog_errno(LOG_ERR, "Unable to receive control header");
                goto end;
        }

        error = nv_get_int16(cnvin, "error");
        if (error != 0)
                goto end;

        if ((str = nv_get_string(cnvin, "status")) == NULL) {
                error = ENOENT;
                pjdlog_errno(LOG_ERR, "Field 'status' is missing.");
                goto end;
        }
        nv_add_string(nvout, str, "status%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "dirty"), "dirty%u", no);
        nv_add_uint32(nvout, nv_get_uint32(cnvin, "extentsize"),
            "extentsize%u", no);
        nv_add_uint32(nvout, nv_get_uint32(cnvin, "keepdirty"),
            "keepdirty%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_read"),
            "stat_read%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_write"),
            "stat_write%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_delete"),
            "stat_delete%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_flush"),
            "stat_flush%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_activemap_update"),
            "stat_activemap_update%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_read_error"),
            "stat_read_error%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_write_error"),
            "stat_write_error%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_delete_error"),
            "stat_delete_error%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "stat_flush_error"),
            "stat_flush_error%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "idle_queue_size"),
            "idle_queue_size%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "local_queue_size"),
            "local_queue_size%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "send_queue_size"),
            "send_queue_size%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "recv_queue_size"),
            "recv_queue_size%u", no);
        nv_add_uint64(nvout, nv_get_uint64(cnvin, "done_queue_size"),
            "done_queue_size%u", no);
end:
        if (cnvin != NULL)
                nv_free(cnvin);
        if (cnvout != NULL)
                nv_free(cnvout);
        if (error != 0)
                nv_add_int16(nvout, error, "error");
}

static void
control_status(struct hastd_config *cfg, struct nv *nvout,
    struct hast_resource *res, const char *name, unsigned int no)
{

        PJDLOG_ASSERT(cfg != NULL);
        PJDLOG_ASSERT(nvout != NULL);
        PJDLOG_ASSERT(name != NULL);

        /* Name is always needed. */
        nv_add_string(nvout, name, "resource%u", no);

        if (res == NULL) {
                TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
                        if (strcmp(res->hr_name, name) == 0)
                                break;
                }
                if (res == NULL) {
                        nv_add_int16(nvout, EHAST_NOENTRY, "error%u", no);
                        return;
                }
        }
        PJDLOG_ASSERT(res != NULL);
        nv_add_string(nvout, res->hr_provname, "provname%u", no);
        nv_add_string(nvout, res->hr_localpath, "localpath%u", no);
        nv_add_string(nvout, res->hr_remoteaddr, "remoteaddr%u", no);
        if (res->hr_sourceaddr[0] != '\0')
                nv_add_string(nvout, res->hr_sourceaddr, "sourceaddr%u", no);
        switch (res->hr_replication) {
        case HAST_REPLICATION_FULLSYNC:
                nv_add_string(nvout, "fullsync", "replication%u", no);
                break;
        case HAST_REPLICATION_MEMSYNC:
                nv_add_string(nvout, "memsync", "replication%u", no);
                break;
        case HAST_REPLICATION_ASYNC:
                nv_add_string(nvout, "async", "replication%u", no);
                break;
        default:
                nv_add_string(nvout, "unknown", "replication%u", no);
                break;
        }
        nv_add_string(nvout, checksum_name(res->hr_checksum),
            "checksum%u", no);
        nv_add_string(nvout, compression_name(res->hr_compression),
            "compression%u", no);
        nv_add_string(nvout, role2str(res->hr_role), "role%u", no);
        nv_add_int32(nvout, res->hr_workerpid, "workerpid%u", no);

        switch (res->hr_role) {
        case HAST_ROLE_PRIMARY:
                PJDLOG_ASSERT(res->hr_workerpid != 0);
                /* FALLTHROUGH */
        case HAST_ROLE_SECONDARY:
                if (res->hr_workerpid != 0)
                        break;
                /* FALLTHROUGH */
        default:
                return;
        }

        /*
         * If we are here, it means that we have a worker process, which we
         * want to ask some questions.
         */
        control_status_worker(res, nvout, no);
}

void
control_handle(struct hastd_config *cfg)
{
        struct proto_conn *conn;
        struct nv *nvin, *nvout;
        unsigned int ii;
        const char *str;
        uint8_t cmd, role;
        int error;

        if (proto_accept(cfg->hc_controlconn, &conn) == -1) {
                pjdlog_errno(LOG_ERR, "Unable to accept control connection");
                return;
        }

        cfg->hc_controlin = conn;
        nvin = nvout = NULL;
        role = HAST_ROLE_UNDEF;

        if (hast_proto_recv_hdr(conn, &nvin) == -1) {
                pjdlog_errno(LOG_ERR, "Unable to receive control header");
                nvin = NULL;
                goto close;
        }

        /* Obtain command code. 0 means that nv_get_uint8() failed. */
        cmd = nv_get_uint8(nvin, "cmd");
        if (cmd == 0) {
                pjdlog_error("Control header is missing 'cmd' field.");
                goto close;
        }

        /* Allocate outgoing nv structure. */
        nvout = nv_alloc();
        if (nvout == NULL) {
                pjdlog_error("Unable to allocate header for control response.");
                goto close;
        }

        error = 0;

        str = nv_get_string(nvin, "resource0");
        if (str == NULL) {
                pjdlog_error("Control header is missing 'resource0' field.");
                error = EHAST_INVALID;
                goto fail;
        }
        if (cmd == HASTCTL_CMD_SETROLE) {
                role = nv_get_uint8(nvin, "role");
                switch (role) {
                case HAST_ROLE_INIT:
                case HAST_ROLE_PRIMARY:
                case HAST_ROLE_SECONDARY:
                        break;
                default:
                        pjdlog_error("Invalid role received (%hhu).", role);
                        error = EHAST_INVALID;
                        goto fail;
                }
        }
        if (strcmp(str, "all") == 0) {
                struct hast_resource *res;

                /* All configured resources. */

                ii = 0;
                TAILQ_FOREACH(res, &cfg->hc_resources, hr_next) {
                        switch (cmd) {
                        case HASTCTL_CMD_SETROLE:
                                control_set_role_common(cfg, nvout, role, res,
                                    res->hr_name, ii++);
                                break;
                        case HASTCTL_CMD_STATUS:
                                control_status(cfg, nvout, res, res->hr_name,
                                    ii++);
                                break;
                        default:
                                pjdlog_error("Invalid command received (%hhu).",
                                    cmd);
                                error = EHAST_UNIMPLEMENTED;
                                goto fail;
                        }
                }
        } else {
                /* Only selected resources. */

                for (ii = 0; ; ii++) {
                        str = nv_get_string(nvin, "resource%u", ii);
                        if (str == NULL)
                                break;
                        switch (cmd) {
                        case HASTCTL_CMD_SETROLE:
                                control_set_role_common(cfg, nvout, role, NULL,
                                    str, ii);
                                break;
                        case HASTCTL_CMD_STATUS:
                                control_status(cfg, nvout, NULL, str, ii);
                                break;
                        default:
                                pjdlog_error("Invalid command received (%hhu).",
                                    cmd);
                                error = EHAST_UNIMPLEMENTED;
                                goto fail;
                        }
                }
        }
        if (nv_error(nvout) != 0)
                goto close;
fail:
        if (error != 0)
                nv_add_int16(nvout, error, "error");

        if (hast_proto_send(NULL, conn, nvout, NULL, 0) == -1)
                pjdlog_errno(LOG_ERR, "Unable to send control response");
close:
        if (nvin != NULL)
                nv_free(nvin);
        if (nvout != NULL)
                nv_free(nvout);
        proto_close(conn);
        cfg->hc_controlin = NULL;
}

/*
 * Thread handles control requests from the parent.
 */
void *
ctrl_thread(void *arg)
{
        struct hast_resource *res = arg;
        struct nv *nvin, *nvout;
        uint8_t cmd;

        for (;;) {
                if (hast_proto_recv_hdr(res->hr_ctrl, &nvin) == -1) {
                        if (sigexit_received)
                                pthread_exit(NULL);
                        pjdlog_errno(LOG_ERR,
                            "Unable to receive control message");
                        kill(getpid(), SIGTERM);
                        pthread_exit(NULL);
                }
                cmd = nv_get_uint8(nvin, "cmd");
                if (cmd == 0) {
                        pjdlog_error("Control message is missing 'cmd' field.");
                        nv_free(nvin);
                        continue;
                }
                nvout = nv_alloc();
                switch (cmd) {
                case CONTROL_STATUS:
                        if (res->hr_remotein != NULL &&
                            res->hr_remoteout != NULL) {
                                nv_add_string(nvout, "complete", "status");
                        } else {
                                nv_add_string(nvout, "degraded", "status");
                        }
                        nv_add_uint32(nvout, (uint32_t)res->hr_extentsize,
                            "extentsize");
                        if (res->hr_role == HAST_ROLE_PRIMARY) {
                                nv_add_uint32(nvout,
                                    (uint32_t)res->hr_keepdirty, "keepdirty");
                                nv_add_uint64(nvout,
                                    (uint64_t)(activemap_ndirty(res->hr_amp) *
                                    res->hr_extentsize), "dirty");
                        } else {
                                nv_add_uint32(nvout, (uint32_t)0, "keepdirty");
                                nv_add_uint64(nvout, (uint64_t)0, "dirty");
                        }
                        nv_add_uint64(nvout, res->hr_stat_read, "stat_read");
                        nv_add_uint64(nvout, res->hr_stat_write, "stat_write");
                        nv_add_uint64(nvout, res->hr_stat_delete,
                            "stat_delete");
                        nv_add_uint64(nvout, res->hr_stat_flush, "stat_flush");
                        nv_add_uint64(nvout, res->hr_stat_activemap_update,
                            "stat_activemap_update");
                        nv_add_uint64(nvout, res->hr_stat_read_error,
                            "stat_read_error");
                        nv_add_uint64(nvout, res->hr_stat_write_error +
                            res->hr_stat_activemap_write_error,
                            "stat_write_error");
                        nv_add_uint64(nvout, res->hr_stat_delete_error,
                            "stat_delete_error");
                        nv_add_uint64(nvout, res->hr_stat_flush_error +
                            res->hr_stat_activemap_flush_error,
                            "stat_flush_error");
                        res->output_status_aux(nvout);
                        nv_add_int16(nvout, 0, "error");
                        break;
                case CONTROL_RELOAD:
                        /*
                         * When parent receives SIGHUP and discovers that
                         * something related to us has changes, it sends reload
                         * message to us.
                         */
                        PJDLOG_ASSERT(res->hr_role == HAST_ROLE_PRIMARY);
                        primary_config_reload(res, nvin);
                        nv_add_int16(nvout, 0, "error");
                        break;
                default:
                        nv_add_int16(nvout, EINVAL, "error");
                        break;
                }
                nv_free(nvin);
                if (nv_error(nvout) != 0) {
                        pjdlog_error("Unable to create answer on control message.");
                        nv_free(nvout);
                        continue;
                }
                if (hast_proto_send(NULL, res->hr_ctrl, nvout, NULL, 0) == -1) {
                        pjdlog_errno(LOG_ERR,
                            "Unable to send reply to control message");
                }
                nv_free(nvout);
        }
        /* NOTREACHED */
        return (NULL);
}