/*-
 * Copyright (c) 2005 Michael Bushkov <bushman@rsu.ru>
 * All rights reserved.
 *
 * 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 AUTHOR 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 AUTHOR 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.
 *
 * $FreeBSD: src/usr.sbin/nscd/mp_rs_query.c,v 1.4 2008/10/12 00:44:27 delphij Exp $
 */

#include <sys/socket.h>
#include <sys/time.h>
#include <sys/types.h>
#include <sys/event.h>
#include <assert.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>

#include "cachelib.h"
#include "config.h"
#include "debug.h"
#include "log.h"
#include "query.h"
#include "mp_rs_query.h"
#include "mp_ws_query.h"
#include "singletons.h"

static int on_mp_read_session_close_notification(struct query_state *);
static void on_mp_read_session_destroy(struct query_state *);
static int on_mp_read_session_mapper(struct query_state *);
/* int on_mp_read_session_request_read1(struct query_state *); */
static int on_mp_read_session_request_read2(struct query_state *);
static int on_mp_read_session_request_process(struct query_state *);
static int on_mp_read_session_response_write1(struct query_state *);
static int on_mp_read_session_read_request_process(struct query_state *);
static int on_mp_read_session_read_response_write1(struct query_state *);
static int on_mp_read_session_read_response_write2(struct query_state *);

/*
 * This function is used as the query_state's destroy_func to make the
 * proper cleanup in case of errors.
 */
static void
on_mp_read_session_destroy(struct query_state *qstate)
{
        TRACE_IN(on_mp_read_session_destroy);
        finalize_comm_element(&qstate->request);
        finalize_comm_element(&qstate->response);

        if (qstate->mdata != NULL) {
                configuration_lock_entry(qstate->config_entry, CELT_MULTIPART);
                close_cache_mp_read_session(
                        (cache_mp_read_session)qstate->mdata);
                configuration_unlock_entry(qstate->config_entry,
                        CELT_MULTIPART);
        }
        TRACE_OUT(on_mp_read_session_destroy);
}

/*
 * The functions below are used to process multipart read session initiation
 * requests.
 * - on_mp_read_session_request_read1 and on_mp_read_session_request_read2 read
 *   the request itself
 * - on_mp_read_session_request_process processes it
 * - on_mp_read_session_response_write1 sends the response
 */
int
on_mp_read_session_request_read1(struct query_state *qstate)
{
        struct cache_mp_read_session_request    *c_mp_rs_request;
        ssize_t result;

        TRACE_IN(on_mp_read_session_request_read1);
        if (qstate->kevent_watermark == 0)
                qstate->kevent_watermark = sizeof(size_t);
        else {
                init_comm_element(&qstate->request,
                        CET_MP_READ_SESSION_REQUEST);
                c_mp_rs_request = get_cache_mp_read_session_request(
                        &qstate->request);

                result = qstate->read_func(qstate,
                        &c_mp_rs_request->entry_length, sizeof(size_t));

                if (result != sizeof(size_t)) {
                        TRACE_OUT(on_mp_read_session_request_read1);
                        return (-1);
                }

                if (BUFSIZE_INVALID(c_mp_rs_request->entry_length)) {
                        TRACE_OUT(on_mp_read_session_request_read1);
                        return (-1);
                }

                c_mp_rs_request->entry = (char *)calloc(1,
                        c_mp_rs_request->entry_length + 1);
                assert(c_mp_rs_request->entry != NULL);

                qstate->kevent_watermark = c_mp_rs_request->entry_length;
                qstate->process_func = on_mp_read_session_request_read2;
        }
        TRACE_OUT(on_mp_read_session_request_read1);
        return (0);
}

static int
on_mp_read_session_request_read2(struct query_state *qstate)
{
        struct cache_mp_read_session_request    *c_mp_rs_request;
        ssize_t result;

        TRACE_IN(on_mp_read_session_request_read2);
        c_mp_rs_request = get_cache_mp_read_session_request(&qstate->request);

        result = qstate->read_func(qstate, c_mp_rs_request->entry,
                c_mp_rs_request->entry_length);

        if (result != qstate->kevent_watermark) {
                LOG_ERR_3("on_mp_read_session_request_read2",
                        "read failed");
                TRACE_OUT(on_mp_read_session_request_read2);
                return (-1);
        }

        qstate->kevent_watermark = 0;
        qstate->process_func = on_mp_read_session_request_process;
        TRACE_OUT(on_mp_read_session_request_read2);
        return (0);
}

static int
on_mp_read_session_request_process(struct query_state *qstate)
{
        struct cache_mp_read_session_request    *c_mp_rs_request;
        struct cache_mp_read_session_response   *c_mp_rs_response;
        cache_mp_read_session   rs;
        cache_entry     c_entry;
        char    *dec_cache_entry_name;

        char *buffer;
        size_t buffer_size;
        cache_mp_write_session ws;
        struct agent    *lookup_agent;
        struct multipart_agent *mp_agent;
        void *mdata;
        int res;

        TRACE_IN(on_mp_read_session_request_process);
        init_comm_element(&qstate->response, CET_MP_READ_SESSION_RESPONSE);
        c_mp_rs_response = get_cache_mp_read_session_response(
                &qstate->response);
        c_mp_rs_request = get_cache_mp_read_session_request(&qstate->request);

        qstate->config_entry = configuration_find_entry(
                s_configuration, c_mp_rs_request->entry);
        if (qstate->config_entry == NULL) {
                c_mp_rs_response->error_code = ENOENT;

                LOG_ERR_2("read_session_request",
                        "can't find configuration entry '%s'."
                        " aborting request", c_mp_rs_request->entry);
                goto fin;
        }

        if (qstate->config_entry->enabled == 0) {
                c_mp_rs_response->error_code = EACCES;

                LOG_ERR_2("read_session_request",
                        "configuration entry '%s' is disabled",
                        c_mp_rs_request->entry);
                goto fin;
        }

        if (qstate->config_entry->perform_actual_lookups != 0)
                dec_cache_entry_name = strdup(
                        qstate->config_entry->mp_cache_params.entry_name);
        else {
#ifdef NS_NSCD_EID_CHECKING
                if (check_query_eids(qstate) != 0) {
                        c_mp_rs_response->error_code = EPERM;
                        goto fin;
                }
#endif

                asprintf(&dec_cache_entry_name, "%s%s", qstate->eid_str,
                        qstate->config_entry->mp_cache_params.entry_name);
        }

        assert(dec_cache_entry_name != NULL);

        configuration_lock_rdlock(s_configuration);
        c_entry = find_cache_entry(s_cache, dec_cache_entry_name);
        configuration_unlock(s_configuration);

        if ((c_entry == INVALID_CACHE) &&
           (qstate->config_entry->perform_actual_lookups != 0))
                c_entry = register_new_mp_cache_entry(qstate,
                        dec_cache_entry_name);

        free(dec_cache_entry_name);

        if (c_entry != INVALID_CACHE_ENTRY) {
                configuration_lock_entry(qstate->config_entry, CELT_MULTIPART);
                rs = open_cache_mp_read_session(c_entry);
                configuration_unlock_entry(qstate->config_entry,
                        CELT_MULTIPART);

                if ((rs == INVALID_CACHE_MP_READ_SESSION) &&
                   (qstate->config_entry->perform_actual_lookups != 0)) {
                        lookup_agent = find_agent(s_agent_table,
                                c_mp_rs_request->entry, MULTIPART_AGENT);

                        if ((lookup_agent != NULL) &&
                        (lookup_agent->type == MULTIPART_AGENT)) {
                                mp_agent = (struct multipart_agent *)
                                        lookup_agent;
                                mdata = mp_agent->mp_init_func();

                                /*
                                 * Multipart agents read the whole snapshot
                                 * of the data at one time.
                                 */
                                configuration_lock_entry(qstate->config_entry,
                                        CELT_MULTIPART);
                                ws = open_cache_mp_write_session(c_entry);
                                configuration_unlock_entry(qstate->config_entry,
                                        CELT_MULTIPART);
                                if (ws != NULL) {
                                    do {
                                        buffer = NULL;
                                        res = mp_agent->mp_lookup_func(&buffer,
                                                &buffer_size,
                                                mdata);

                                        if ((res & NS_TERMINATE) &&
                                           (buffer != NULL)) {
                                                configuration_lock_entry(
                                                        qstate->config_entry,
                                                        CELT_MULTIPART);
                                                if (cache_mp_write(ws, buffer,
                                                    buffer_size) != 0) {
                                                        abandon_cache_mp_write_session(ws);
                                                        ws = NULL;
                                                }
                                                configuration_unlock_entry(
                                                        qstate->config_entry,
                                                        CELT_MULTIPART);

                                                free(buffer);
                                                buffer = NULL;
                                        } else {
                                                configuration_lock_entry(
                                                        qstate->config_entry,
                                                        CELT_MULTIPART);
                                                close_cache_mp_write_session(ws);
                                                configuration_unlock_entry(
                                                        qstate->config_entry,
                                                        CELT_MULTIPART);

                                                free(buffer);
                                                buffer = NULL;
                                        }
                                    } while ((res & NS_TERMINATE) &&
                                            (ws != NULL));
                                }

                                configuration_lock_entry(qstate->config_entry,
                                        CELT_MULTIPART);
                                rs = open_cache_mp_read_session(c_entry);
                                configuration_unlock_entry(qstate->config_entry,
                                        CELT_MULTIPART);
                        }
                }

                if (rs == INVALID_CACHE_MP_READ_SESSION)
                        c_mp_rs_response->error_code = -1;
                else {
                    qstate->mdata = rs;
                    qstate->destroy_func = on_mp_read_session_destroy;

                    configuration_lock_entry(qstate->config_entry,
                        CELT_MULTIPART);
                    if ((qstate->config_entry->mp_query_timeout.tv_sec != 0) ||
                    (qstate->config_entry->mp_query_timeout.tv_usec != 0))
                        memcpy(&qstate->timeout,
                            &qstate->config_entry->mp_query_timeout,
                            sizeof(struct timeval));
                    configuration_unlock_entry(qstate->config_entry,
                        CELT_MULTIPART);
                }
        } else
                c_mp_rs_response->error_code = -1;

fin:
        qstate->process_func = on_mp_read_session_response_write1;
        qstate->kevent_watermark = sizeof(int);
        qstate->kevent_filter = EVFILT_WRITE;

        TRACE_OUT(on_mp_read_session_request_process);
        return (0);
}

static int
on_mp_read_session_response_write1(struct query_state *qstate)
{
        struct cache_mp_read_session_response   *c_mp_rs_response;
        ssize_t result;

        TRACE_IN(on_mp_read_session_response_write1);
        c_mp_rs_response = get_cache_mp_read_session_response(
                &qstate->response);
        result = qstate->write_func(qstate, &c_mp_rs_response->error_code,
                sizeof(int));

        if (result != sizeof(int)) {
                LOG_ERR_3("on_mp_read_session_response_write1",
                        "write failed");
                TRACE_OUT(on_mp_read_session_response_write1);
                return (-1);
        }

        if (c_mp_rs_response->error_code == 0) {
                qstate->kevent_watermark = sizeof(int);
                qstate->process_func = on_mp_read_session_mapper;
                qstate->kevent_filter = EVFILT_READ;
        } else {
                qstate->kevent_watermark = 0;
                qstate->process_func = NULL;
        }
        TRACE_OUT(on_mp_read_session_response_write1);
        return (0);
}

/*
 * Mapper function is used to avoid multiple connections for each session
 * write or read requests. After processing the request, it does not close
 * the connection, but waits for the next request.
 */
static int
on_mp_read_session_mapper(struct query_state *qstate)
{
        ssize_t result;
        int elem_type;

        TRACE_IN(on_mp_read_session_mapper);
        if (qstate->kevent_watermark == 0) {
                qstate->kevent_watermark = sizeof(int);
        } else {
                result = qstate->read_func(qstate, &elem_type, sizeof(int));
                if (result != sizeof(int)) {
                        LOG_ERR_3("on_mp_read_session_mapper",
                                "read failed");
                        TRACE_OUT(on_mp_read_session_mapper);
                        return (-1);
                }

                switch (elem_type) {
                case CET_MP_READ_SESSION_READ_REQUEST:
                        qstate->kevent_watermark = 0;
                        qstate->process_func =
                                on_mp_read_session_read_request_process;
                        break;
                case CET_MP_READ_SESSION_CLOSE_NOTIFICATION:
                        qstate->kevent_watermark = 0;
                        qstate->process_func =
                                on_mp_read_session_close_notification;
                        break;
                default:
                        qstate->kevent_watermark = 0;
                        qstate->process_func = NULL;
                        LOG_ERR_3("on_mp_read_session_mapper",
                                "unknown element type");
                        TRACE_OUT(on_mp_read_session_mapper);
                        return (-1);
                }
        }
        TRACE_OUT(on_mp_read_session_mapper);
        return (0);
}

/*
 * The functions below are used to process multipart read sessions read
 * requests. User doesn't have to pass any kind of data, besides the
 * request identificator itself. So we don't need any XXX_read functions and
 * start with the XXX_process function.
 * - on_mp_read_session_read_request_process processes it
 * - on_mp_read_session_read_response_write1 and
 *   on_mp_read_session_read_response_write2 sends the response
 */
static int
on_mp_read_session_read_request_process(struct query_state *qstate)
{
        struct cache_mp_read_session_read_response      *read_response;

        TRACE_IN(on_mp_read_session_response_process);
        init_comm_element(&qstate->response, CET_MP_READ_SESSION_READ_RESPONSE);
        read_response = get_cache_mp_read_session_read_response(
                &qstate->response);

        configuration_lock_entry(qstate->config_entry, CELT_MULTIPART);
        read_response->error_code = cache_mp_read(
                (cache_mp_read_session)qstate->mdata, NULL,
                &read_response->data_size);

        if (read_response->error_code == 0) {
                read_response->data = (char *)malloc(read_response->data_size);
                assert(read_response != NULL);
                read_response->error_code = cache_mp_read(
                        (cache_mp_read_session)qstate->mdata,
                        read_response->data,
                        &read_response->data_size);
        }
        configuration_unlock_entry(qstate->config_entry, CELT_MULTIPART);

        if (read_response->error_code == 0)
                qstate->kevent_watermark = sizeof(size_t) + sizeof(int);
        else
                qstate->kevent_watermark = sizeof(int);
        qstate->process_func = on_mp_read_session_read_response_write1;
        qstate->kevent_filter = EVFILT_WRITE;

        TRACE_OUT(on_mp_read_session_response_process);
        return (0);
}

static int
on_mp_read_session_read_response_write1(struct query_state *qstate)
{
        struct cache_mp_read_session_read_response      *read_response;
        ssize_t result;

        TRACE_IN(on_mp_read_session_read_response_write1);
        read_response = get_cache_mp_read_session_read_response(
                &qstate->response);

        result = qstate->write_func(qstate, &read_response->error_code,
                sizeof(int));
        if (read_response->error_code == 0) {
                result += qstate->write_func(qstate, &read_response->data_size,
                        sizeof(size_t));
                if (result != qstate->kevent_watermark) {
                        TRACE_OUT(on_mp_read_session_read_response_write1);
                        LOG_ERR_3("on_mp_read_session_read_response_write1",
                                "write failed");
                        return (-1);
                }

                qstate->kevent_watermark = read_response->data_size;
                qstate->process_func = on_mp_read_session_read_response_write2;
        } else {
                if (result != qstate->kevent_watermark) {
                        LOG_ERR_3("on_mp_read_session_read_response_write1",
                                "write failed");
                        TRACE_OUT(on_mp_read_session_read_response_write1);
                        return (-1);
                }

                qstate->kevent_watermark = 0;
                qstate->process_func = NULL;
        }

        TRACE_OUT(on_mp_read_session_read_response_write1);
        return (0);
}

static int
on_mp_read_session_read_response_write2(struct query_state *qstate)
{
        struct cache_mp_read_session_read_response *read_response;
        ssize_t result;

        TRACE_IN(on_mp_read_session_read_response_write2);
        read_response = get_cache_mp_read_session_read_response(
                &qstate->response);
        result = qstate->write_func(qstate, read_response->data,
                read_response->data_size);
        if (result != qstate->kevent_watermark) {
                LOG_ERR_3("on_mp_read_session_read_response_write2",
                        "write failed");
                TRACE_OUT(on_mp_read_session_read_response_write2);
                return (-1);
        }

        finalize_comm_element(&qstate->request);
        finalize_comm_element(&qstate->response);

        qstate->kevent_watermark = sizeof(int);
        qstate->process_func = on_mp_read_session_mapper;
        qstate->kevent_filter = EVFILT_READ;

        TRACE_OUT(on_mp_read_session_read_response_write2);
        return (0);
}

/*
 * Handles session close notification by calling close_cache_mp_read_session
 * function.
 */
static int
on_mp_read_session_close_notification(struct query_state *qstate)
{

        TRACE_IN(on_mp_read_session_close_notification);
        configuration_lock_entry(qstate->config_entry, CELT_MULTIPART);
        close_cache_mp_read_session((cache_mp_read_session)qstate->mdata);
        configuration_unlock_entry(qstate->config_entry, CELT_MULTIPART);
        qstate->mdata = NULL;
        qstate->kevent_watermark = 0;
        qstate->process_func = NULL;
        TRACE_OUT(on_mp_read_session_close_notification);
        return (0);
}