/* Licensed to the Apache Software Foundation (ASF) under one or more

 * contributor license agreements.  See the NOTICE file distributed with

 * this work for additional information regarding copyright ownership.

 * The ASF licenses this file to You under the Apache License, Version 2.0

 * (the "License"); you may not use this file except in compliance with

 * the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

#include "ap_config.h"

#include "ap_mmn.h"

#include "httpd.h"

#include "http_config.h"

#include "http_connection.h"

#include "http_core.h"

#include "http_log.h"

#include "apr_buckets.h"

#include "apr_strings.h"

#include "util_filter.h"

#include "scoreboard.h"

module AP_MODULE_DECLARE_DATA echo_module;

typedef struct {

    int bEnabled;

} EchoConfig;

static void *create_echo_server_config(apr_pool_t *p, server_rec *s)

{

    EchoConfig *pConfig = apr_pcalloc(p, sizeof *pConfig);

    pConfig->bEnabled = 0;

    return pConfig;

}

static const char *echo_on(cmd_parms *cmd, void *dummy, int arg)

{

    EchoConfig *pConfig = ap_get_module_config(cmd->server->module_config,

                                               &echo_module);

    pConfig->bEnabled = arg;

    return NULL;

}

static apr_status_t brigade_peek(apr_bucket_brigade *bbIn,

                                 char *buff, apr_size_t bufflen)

{

    apr_bucket *b;

    apr_size_t readbytes = 0;

    if (bufflen--)

        /* compensate for NULL */

        *buff = '\0';

    else

        return APR_EGENERAL;

    if (APR_BRIGADE_EMPTY(bbIn))

        return APR_EGENERAL;

    b = APR_BRIGADE_FIRST(bbIn);

    while ((b != APR_BRIGADE_SENTINEL(bbIn)) && (readbytes < bufflen)) {

        const char *pos;

        const char *str;

        apr_size_t len;

        apr_status_t rv;

        if ((rv = apr_bucket_read(b, &str, &len, APR_NONBLOCK_READ))

                != APR_SUCCESS)

            return rv;

        if ((pos = memchr(str, APR_ASCII_LF, len)) != NULL)

            len = pos - str;

        if (len > bufflen - readbytes)

            len = bufflen - readbytes;

        memcpy (buff + readbytes, str, len);

        readbytes += len;

        buff[readbytes] = '\0';

        b = APR_BUCKET_NEXT(b);

    }

    return APR_SUCCESS;

}

static int update_echo_child_status(ap_sb_handle_t *sbh,

                                    int status, conn_rec *c,

                                    apr_bucket_brigade *last_echoed)

{

    worker_score *ws = ap_get_scoreboard_worker(sbh);

    int old_status = ws->status;

    ws->status = status;

    if (!ap_extended_status)

        return old_status;

    ws->last_used = apr_time_now();

    /* initial pass only, please - in the name of efficiency */

    if (c) {

        apr_cpystrn(ws->client64,

                    ap_get_remote_host(c, c->base_server->lookup_defaults,

                                       REMOTE_NOLOOKUP, NULL),

                    sizeof(ws->client64));

        apr_cpystrn(ws->vhost, c->base_server->server_hostname,

                    sizeof(ws->vhost));

        /* Deliberate trailing space - filling in string on WRITE passes */

        apr_cpystrn(ws->request, "ECHO ", sizeof(ws->request));

    }

    /* each subsequent WRITE pass, let's update what we echoed */

    if (last_echoed) {

        brigade_peek(last_echoed, ws->request + sizeof("ECHO ") - 1,

                     sizeof(ws->request) - sizeof("ECHO ") + 1);

    }

    return old_status;

}

static int process_echo_connection(conn_rec *c)

{

    apr_bucket_brigade *bb;

    apr_bucket *b;

    apr_socket_t *csd = NULL;

    EchoConfig *pConfig = ap_get_module_config(c->base_server->module_config,

                                               &echo_module);

    if (!pConfig->bEnabled) {

        return DECLINED;

    }

    ap_time_process_request(c->sbh, START_PREQUEST);

    update_echo_child_status(c->sbh, SERVER_BUSY_READ, c, NULL);

    bb = apr_brigade_create(c->pool, c->bucket_alloc);

    for ( ; ; ) {

        apr_status_t rv;

        /* Get a single line of input from the client */

        if (((rv = ap_get_brigade(c->input_filters, bb, AP_MODE_GETLINE,

                                  APR_BLOCK_READ, 0)) != APR_SUCCESS)) {

            apr_brigade_cleanup(bb);

            if (!APR_STATUS_IS_EOF(rv) && ! APR_STATUS_IS_TIMEUP(rv))

                ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01611)

                             "ProtocolEcho: Failure reading from %s",

                             c->client_ip);

            break;

        }

        /* Something horribly wrong happened.  Someone didn't block! */

        if (APR_BRIGADE_EMPTY(bb)) {

            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01612)

                         "ProtocolEcho: Error - read empty brigade from %s!",

                         c->client_ip);

            break;

        }

        if (!csd) {

            csd = ap_get_conn_socket(c);

            apr_socket_timeout_set(csd, c->base_server->keep_alive_timeout);

        }

        update_echo_child_status(c->sbh, SERVER_BUSY_WRITE, NULL, bb);

        /* Make sure the data is flushed to the client */

        b = apr_bucket_flush_create(c->bucket_alloc);

        APR_BRIGADE_INSERT_TAIL(bb, b);

        rv = ap_pass_brigade(c->output_filters, bb);

        if (rv != APR_SUCCESS) {

            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01613)

                         "ProtocolEcho: Failure writing to %s",

                         c->client_ip);

            break;

        }

        apr_brigade_cleanup(bb);

        /* Announce our intent to loop */

        update_echo_child_status(c->sbh, SERVER_BUSY_KEEPALIVE, NULL, NULL);

    }

    apr_brigade_destroy(bb);

    ap_time_process_request(c->sbh, STOP_PREQUEST);

    update_echo_child_status(c->sbh, SERVER_CLOSING, c, NULL);

    return OK;

}

static const command_rec echo_cmds[] =

{

    AP_INIT_FLAG("ProtocolEcho", echo_on, NULL, RSRC_CONF,

                 "Run an echo server on this host"),

    { NULL }

};

static void register_hooks(apr_pool_t *p)

{

    ap_hook_process_connection(process_echo_connection, NULL, NULL,

                               APR_HOOK_MIDDLE);

}

AP_DECLARE_MODULE(echo) = {

    STANDARD20_MODULE_STUFF,

    NULL,                       /* create per-directory config structure */

    NULL,                       /* merge per-directory config structures */

    create_echo_server_config,  /* create per-server config structure */

    NULL,                       /* merge per-server config structures */

    echo_cmds,                  /* command apr_table_t */

    register_hooks              /* register hooks */

};