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 "httpd.h"
18#include "http_log.h"
19#include "http_request.h"
20#include "http_config.h"
21#include "http_protocol.h"
22
23#include "apr_strings.h"
24#include "apr_time.h"
25
26#include "ap_socache.h"
27
28#include "distcache/dc_client.h"
29
30#if !defined(DISTCACHE_CLIENT_API) || (DISTCACHE_CLIENT_API < 0x0001)
31#error "You must compile with a more recent version of the distcache-base package"
32#endif
33
34struct ap_socache_instance_t {
35    /* Configured target server: */
36    const char *target;
37    /* distcache client context: */
38    DC_CTX *dc;
39};
40
41static const char *socache_dc_create(ap_socache_instance_t **context,
42                                     const char *arg,
43                                     apr_pool_t *tmp, apr_pool_t *p)
44{
45    struct ap_socache_instance_t *ctx;
46
47    ctx = *context = apr_palloc(p, sizeof *ctx);
48
49    ctx->target = apr_pstrdup(p, arg);
50
51    return NULL;
52}
53
54static apr_status_t socache_dc_init(ap_socache_instance_t *ctx,
55                                    const char *namespace,
56                                    const struct ap_socache_hints *hints,
57                                    server_rec *s, apr_pool_t *p)
58{
59#if 0
60    /* If a "persistent connection" mode of operation is preferred, you *must*
61     * also use the PIDCHECK flag to ensure fork()'d processes don't interlace
62     * comms on the same connection as each other. */
63#define SESSION_CTX_FLAGS        SESSION_CTX_FLAG_PERSISTENT | \
64                                 SESSION_CTX_FLAG_PERSISTENT_PIDCHECK | \
65                                 SESSION_CTX_FLAG_PERSISTENT_RETRY | \
66                                 SESSION_CTX_FLAG_PERSISTENT_LATE
67#else
68    /* This mode of operation will open a temporary connection to the 'target'
69     * for each cache operation - this makes it safe against fork()
70     * automatically. This mode is preferred when running a local proxy (over
71     * unix domain sockets) because overhead is negligable and it reduces the
72     * performance/stability danger of file-descriptor bloatage. */
73#define SESSION_CTX_FLAGS        0
74#endif
75    ctx->dc = DC_CTX_new(ctx->target, SESSION_CTX_FLAGS);
76    if (!ctx->dc) {
77        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00738) "distributed scache failed to obtain context");
78        return APR_EGENERAL;
79    }
80    ap_log_error(APLOG_MARK, APLOG_INFO, 0, s, APLOGNO(00739) "distributed scache context initialised");
81
82    return APR_SUCCESS;
83}
84
85static void socache_dc_destroy(ap_socache_instance_t *ctx, server_rec *s)
86{
87    if (ctx && ctx->dc) {
88        DC_CTX_free(ctx->dc);
89        ctx->dc = NULL;
90    }
91}
92
93static apr_status_t socache_dc_store(ap_socache_instance_t *ctx, server_rec *s,
94                                     const unsigned char *id, unsigned int idlen,
95                                     apr_time_t expiry,
96                                     unsigned char *der, unsigned int der_len,
97                                     apr_pool_t *p)
98{
99    /* !@#$%^ - why do we deal with *absolute* time anyway???
100     * Uhm - because most things expire things at a specific time?
101     * Were the API were thought out expiry - r->request_time is a good approximation
102     */
103    expiry -= apr_time_now();
104    /* Send the serialised session to the distributed cache context */
105    if (!DC_CTX_add_session(ctx->dc, id, idlen, der, der_len,
106                            apr_time_msec(expiry))) {
107        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00740) "distributed scache 'store' failed");
108        return APR_EGENERAL;
109    }
110    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00741) "distributed scache 'store' successful");
111    return APR_SUCCESS;
112}
113
114static apr_status_t socache_dc_retrieve(ap_socache_instance_t *ctx, server_rec *s,
115                                        const unsigned char *id, unsigned int idlen,
116                                        unsigned char *dest, unsigned int *destlen,
117                                        apr_pool_t *p)
118{
119    unsigned int data_len;
120
121    /* Retrieve any corresponding session from the distributed cache context */
122    if (!DC_CTX_get_session(ctx->dc, id, idlen, dest, *destlen, &data_len)) {
123        ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00742) "distributed scache 'retrieve' MISS");
124        return APR_NOTFOUND;
125    }
126    if (data_len > *destlen) {
127        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00743) "distributed scache 'retrieve' OVERFLOW");
128        return APR_ENOSPC;
129    }
130    *destlen = data_len;
131    ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00744) "distributed scache 'retrieve' HIT");
132    return APR_SUCCESS;
133}
134
135static apr_status_t socache_dc_remove(ap_socache_instance_t *ctx,
136                                      server_rec *s, const unsigned char *id,
137                                      unsigned int idlen, apr_pool_t *p)
138{
139    /* Remove any corresponding session from the distributed cache context */
140    if (!DC_CTX_remove_session(ctx->dc, id, idlen)) {
141        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00745) "distributed scache 'remove' MISS");
142        return APR_NOTFOUND;
143    }
144    else {
145        ap_log_error(APLOG_MARK, APLOG_ERR, 0, s, APLOGNO(00746) "distributed scache 'remove' HIT");
146        return APR_SUCCESS;
147    }
148}
149
150static void socache_dc_status(ap_socache_instance_t *ctx, request_rec *r, int flags)
151{
152    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(00747)
153                  "distributed scache 'socache_dc_status'");
154    ap_rprintf(r, "cache type: <b>DC (Distributed Cache)</b>, "
155               " target: <b>%s</b><br>", ctx->target);
156}
157
158static apr_status_t socache_dc_iterate(ap_socache_instance_t *instance,
159                                       server_rec *s, void *userctx,
160                                       ap_socache_iterator_t *iterator,
161                                       apr_pool_t *pool)
162{
163    return APR_ENOTIMPL;
164}
165
166static const ap_socache_provider_t socache_dc = {
167    "distcache",
168    0,
169    socache_dc_create,
170    socache_dc_init,
171    socache_dc_destroy,
172    socache_dc_store,
173    socache_dc_retrieve,
174    socache_dc_remove,
175    socache_dc_status,
176    socache_dc_iterate
177};
178
179static void register_hooks(apr_pool_t *p)
180{
181    ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP, "dc",
182                         AP_SOCACHE_PROVIDER_VERSION,
183                         &socache_dc);
184}
185
186AP_DECLARE_MODULE(socache_dc) = {
187    STANDARD20_MODULE_STUFF,
188    NULL, NULL, NULL, NULL, NULL,
189    register_hooks
190};
191
192