1/* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements.  See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License.  You may obtain a copy of the License at
7 *
8 *     http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "ap_config.h"
18#include "ap_mmn.h"
19#include "httpd.h"
20#include "http_config.h"
21#include "http_connection.h"
22#include "http_core.h"
23#include "http_log.h"
24
25#include "apr_buckets.h"
26#include "apr_strings.h"
27#include "util_filter.h"
28#include "scoreboard.h"
29
30module AP_MODULE_DECLARE_DATA echo_module;
31
32typedef struct {
33    int bEnabled;
34} EchoConfig;
35
36static void *create_echo_server_config(apr_pool_t *p, server_rec *s)
37{
38    EchoConfig *pConfig = apr_pcalloc(p, sizeof *pConfig);
39
40    pConfig->bEnabled = 0;
41
42    return pConfig;
43}
44
45static const char *echo_on(cmd_parms *cmd, void *dummy, int arg)
46{
47    EchoConfig *pConfig = ap_get_module_config(cmd->server->module_config,
48                                               &echo_module);
49    pConfig->bEnabled = arg;
50
51    return NULL;
52}
53
54static apr_status_t brigade_peek(apr_bucket_brigade *bbIn,
55                                 char *buff, apr_size_t bufflen)
56{
57    apr_bucket *b;
58    apr_size_t readbytes = 0;
59
60    if (bufflen--)
61        /* compensate for NULL */
62        *buff = '\0';
63    else
64        return APR_EGENERAL;
65
66    if (APR_BRIGADE_EMPTY(bbIn))
67        return APR_EGENERAL;
68
69    b = APR_BRIGADE_FIRST(bbIn);
70
71    while ((b != APR_BRIGADE_SENTINEL(bbIn)) && (readbytes < bufflen)) {
72        const char *pos;
73        const char *str;
74        apr_size_t len;
75        apr_status_t rv;
76
77        if ((rv = apr_bucket_read(b, &str, &len, APR_NONBLOCK_READ))
78                != APR_SUCCESS)
79            return rv;
80
81        if ((pos = memchr(str, APR_ASCII_LF, len)) != NULL)
82            len = pos - str;
83        if (len > bufflen - readbytes)
84            len = bufflen - readbytes;
85        memcpy (buff + readbytes, str, len);
86        readbytes += len;
87        buff[readbytes] = '\0';
88
89        b = APR_BUCKET_NEXT(b);
90    }
91    return APR_SUCCESS;
92}
93
94
95static int update_echo_child_status(ap_sb_handle_t *sbh,
96                                    int status, conn_rec *c,
97                                    apr_bucket_brigade *last_echoed)
98{
99    worker_score *ws = ap_get_scoreboard_worker(sbh);
100    int old_status = ws->status;
101
102    ws->status = status;
103
104    if (!ap_extended_status)
105        return old_status;
106
107    ws->last_used = apr_time_now();
108
109    /* initial pass only, please - in the name of efficiency */
110    if (c) {
111        apr_cpystrn(ws->client,
112                    ap_get_remote_host(c, c->base_server->lookup_defaults,
113                                       REMOTE_NOLOOKUP, NULL),
114                    sizeof(ws->client));
115        apr_cpystrn(ws->vhost, c->base_server->server_hostname,
116                    sizeof(ws->vhost));
117        /* Deliberate trailing space - filling in string on WRITE passes */
118        apr_cpystrn(ws->request, "ECHO ", sizeof(ws->request));
119    }
120
121    /* each subsequent WRITE pass, let's update what we echoed */
122    if (last_echoed) {
123        brigade_peek(last_echoed, ws->request + sizeof("ECHO ") - 1,
124                     sizeof(ws->request) - sizeof("ECHO ") + 1);
125    }
126
127    return old_status;
128}
129
130static int process_echo_connection(conn_rec *c)
131{
132    apr_bucket_brigade *bb;
133    apr_bucket *b;
134    apr_socket_t *csd = NULL;
135    EchoConfig *pConfig = ap_get_module_config(c->base_server->module_config,
136                                               &echo_module);
137
138    if (!pConfig->bEnabled) {
139        return DECLINED;
140    }
141
142    ap_time_process_request(c->sbh, START_PREQUEST);
143    update_echo_child_status(c->sbh, SERVER_BUSY_READ, c, NULL);
144
145    bb = apr_brigade_create(c->pool, c->bucket_alloc);
146
147    for ( ; ; ) {
148        apr_status_t rv;
149
150        /* Get a single line of input from the client */
151        if (((rv = ap_get_brigade(c->input_filters, bb, AP_MODE_GETLINE,
152                                  APR_BLOCK_READ, 0)) != APR_SUCCESS)) {
153            apr_brigade_cleanup(bb);
154            if (!APR_STATUS_IS_EOF(rv) && ! APR_STATUS_IS_TIMEUP(rv))
155                ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01611)
156                             "ProtocolEcho: Failure reading from %s",
157                             c->client_ip);
158            break;
159        }
160
161        /* Something horribly wrong happened.  Someone didn't block! */
162        if (APR_BRIGADE_EMPTY(bb)) {
163            apr_brigade_cleanup(bb);
164            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01612)
165                         "ProtocolEcho: Error - read empty brigade from %s!",
166                         c->client_ip);
167            break;
168        }
169
170        if (!csd) {
171            csd = ap_get_conn_socket(c);
172            apr_socket_timeout_set(csd, c->base_server->keep_alive_timeout);
173        }
174
175        update_echo_child_status(c->sbh, SERVER_BUSY_WRITE, NULL, bb);
176
177        /* Make sure the data is flushed to the client */
178        b = apr_bucket_flush_create(c->bucket_alloc);
179        APR_BRIGADE_INSERT_TAIL(bb, b);
180        rv = ap_pass_brigade(c->output_filters, bb);
181        if (rv != APR_SUCCESS) {
182            ap_log_error(APLOG_MARK, APLOG_INFO, rv, c->base_server, APLOGNO(01613)
183                         "ProtocolEcho: Failure writing to %s",
184                         c->client_ip);
185            break;
186        }
187        apr_brigade_cleanup(bb);
188
189        /* Announce our intent to loop */
190        update_echo_child_status(c->sbh, SERVER_BUSY_KEEPALIVE, NULL, NULL);
191    }
192    apr_brigade_destroy(bb);
193    ap_time_process_request(c->sbh, STOP_PREQUEST);
194    update_echo_child_status(c->sbh, SERVER_CLOSING, c, NULL);
195    return OK;
196}
197
198static const command_rec echo_cmds[] =
199{
200    AP_INIT_FLAG("ProtocolEcho", echo_on, NULL, RSRC_CONF,
201                 "Run an echo server on this host"),
202    { NULL }
203};
204
205static void register_hooks(apr_pool_t *p)
206{
207    ap_hook_process_connection(process_echo_connection, NULL, NULL,
208                               APR_HOOK_MIDDLE);
209}
210
211AP_DECLARE_MODULE(echo) = {
212    STANDARD20_MODULE_STUFF,
213    NULL,                       /* create per-directory config structure */
214    NULL,                       /* merge per-directory config structures */
215    create_echo_server_config,  /* create per-server config structure */
216    NULL,                       /* merge per-server config structures */
217    echo_cmds,                  /* command apr_table_t */
218    register_hooks              /* register hooks */
219};
220