mod_socache_shmcb.c

                     *buf_len = buf_req + APR_ALIGN_DEFAULT(buf_req / 2);
                     *buf = apr_palloc(pool, *buf_len);
                     id = *buf;
                }

                dest = *buf + APR_ALIGN_DEFAULT(idx->id_len + 1);

                /* Copy out the data, because it's potentially cyclic */
                shmcb_cyclic_cton_memcpy(header->subcache_data_size, id,
                                         SHMCB_DATA(header, subcache),
                                         idx->data_pos, idx->id_len);
                id[idx->id_len] = '\0';

                shmcb_cyclic_cton_memcpy(header->subcache_data_size, dest,
                                         SHMCB_DATA(header, subcache),
                                         data_offset, dest_len);
                dest[dest_len] = '\0';

                rv = iterator(instance, s, userctx, id, idx->id_len,
                              dest, dest_len, pool);
                ap_log_error(APLOG_MARK, APLOG_DEBUG, rv, s, APLOGNO(00855)
                             "shmcb entry iterated");
                if (rv != APR_SUCCESS)
                    return rv;
            }
            else {
                /* Already stale, quietly remove and treat as not-found */
                idx->removed = 1;
                header->stat_expiries++;
                ap_log_error(APLOG_MARK, APLOG_DEBUG, 0, s, APLOGNO(00856)
                             "shmcb_subcache_iterate discarding expired entry");
            }
        }
        /* Increment */
        loop++;
        pos = SHMCB_CYCLIC_INCREMENT(pos, 1, header->index_num);
    }

    return APR_SUCCESS;
}

static const ap_socache_provider_t socache_shmcb = {
    "shmcb",
    AP_SOCACHE_FLAG_NOTMPSAFE,
    socache_shmcb_create,
    socache_shmcb_init,
    socache_shmcb_destroy,
    socache_shmcb_store,
    socache_shmcb_retrieve,
    socache_shmcb_remove,
    socache_shmcb_status,
    socache_shmcb_iterate
};

static void register_hooks(apr_pool_t *p)
{
    ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP, "shmcb",
                         AP_SOCACHE_PROVIDER_VERSION,
                         &socache_shmcb);

    /* Also register shmcb under the default provider name. */
    ap_register_provider(p, AP_SOCACHE_PROVIDER_GROUP,
                         AP_SOCACHE_DEFAULT_PROVIDER,
                         AP_SOCACHE_PROVIDER_VERSION,
                         &socache_shmcb);
}

AP_DECLARE_MODULE(socache_shmcb) = {
    STANDARD20_MODULE_STUFF,
    NULL, NULL, NULL, NULL, NULL,
    register_hooks
};