/* 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 "mod_proxy.h"

#include "apr_dbm.h"

module AP_MODULE_DECLARE_DATA proxy_express_module;

static int proxy_available = 0;

typedef struct {

    const char *dbmfile;

    const char *dbmtype;

    int enabled;

} express_server_conf;

static const char *set_dbmfile(cmd_parms *cmd,

                               void *dconf,

                               const char *arg)

{

    express_server_conf *sconf;

    sconf = ap_get_module_config(cmd->server->module_config, &proxy_express_module);

    if ((sconf->dbmfile = ap_server_root_relative(cmd->pool, arg)) == NULL) {

        return apr_pstrcat(cmd->pool, "ProxyExpressDBMFile: bad path to file: ",

                           arg, NULL);

    }

    return NULL;

}

static const char *set_dbmtype(cmd_parms *cmd,

                               void *dconf,

                               const char *arg)

{

    express_server_conf *sconf;

    sconf = ap_get_module_config(cmd->server->module_config, &proxy_express_module);

    sconf->dbmtype = arg;

    return NULL;

}

static const char *set_enabled(cmd_parms *cmd,

                               void *dconf,

                               int flag)

{

    express_server_conf *sconf;

    sconf = ap_get_module_config(cmd->server->module_config, &proxy_express_module);

    sconf->enabled = flag;

    return NULL;

}

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

{

    express_server_conf *a;

    a = (express_server_conf *)apr_pcalloc(p, sizeof(express_server_conf));

    a->dbmfile = NULL;

    a->dbmtype = "default";

    a->enabled = 0;

    return (void *)a;

}

static void *server_merge(apr_pool_t *p, void *basev, void *overridesv)

{

    express_server_conf *a, *base, *overrides;

    a         = (express_server_conf *)apr_pcalloc(p,

                                                   sizeof(express_server_conf));

    base      = (express_server_conf *)basev;

    overrides = (express_server_conf *)overridesv;

    a->dbmfile = (overrides->dbmfile) ? overrides->dbmfile : base->dbmfile;

    a->dbmtype = (overrides->dbmtype) ? overrides->dbmtype : base->dbmtype;

    a->enabled = (overrides->enabled) ? overrides->enabled : base->enabled;

    return (void *)a;

}

static int post_config(apr_pool_t *p,

                       apr_pool_t *plog,

                       apr_pool_t *ptemp,

                       server_rec *s)

{

    proxy_available = (ap_find_linked_module("mod_proxy.c") != NULL);

    return OK;

}

static int xlate_name(request_rec *r)

{

    int i;

    const char *name;

    char *backend = NULL;

    apr_dbm_t *db;

    apr_status_t rv;

    apr_datum_t key, val;

    struct proxy_alias *ralias;

    proxy_dir_conf *dconf;

    express_server_conf *sconf;

    sconf = ap_get_module_config(r->server->module_config, &proxy_express_module);

    dconf = ap_get_module_config(r->per_dir_config, &proxy_module);

    if (!sconf->enabled) {

        return DECLINED;

    }

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01001) "proxy_express: Enabled");

    if (!sconf->dbmfile || (r->filename && strncmp(r->filename, "proxy:", 6) == 0)) {

        /* it should be go on as an internal proxy request */

        return DECLINED;

    }

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01002)

                  "proxy_express: Opening DBM file: %s (%s)",

                  sconf->dbmfile, sconf->dbmtype);

    rv = apr_dbm_open_ex(&db, sconf->dbmtype, sconf->dbmfile, APR_DBM_READONLY,

                         APR_OS_DEFAULT, r->pool);

    if (rv != APR_SUCCESS) {

        return DECLINED;

    }

    name = ap_get_server_name(r);

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01003)

                  "proxy_express: looking for %s", name);

    key.dptr = (char *)name;

    key.dsize = strlen(key.dptr);

    rv = apr_dbm_fetch(db, key, &val;;

    if (rv == APR_SUCCESS) {

        backend = apr_pstrmemdup(r->pool, val.dptr, val.dsize);

    }

    apr_dbm_close(db);

    if (rv != APR_SUCCESS || !backend) {

        return DECLINED;

    }

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01004)

                  "proxy_express: found %s -> %s", name, backend);

    r->filename = apr_pstrcat(r->pool, "proxy:", backend, r->uri, NULL);

    r->handler = "proxy-server";

    r->proxyreq = PROXYREQ_REVERSE;

    ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01005)

                  "proxy_express: rewritten as: %s", r->filename);

    ralias = (struct proxy_alias *)dconf->raliases->elts;

    /*

     * See if we have already added a ProxyPassReverse entry

     * for this host... If so, don't do it again.

     */

    /*

     * NOTE: dconf is process specific so this will only

     *       work as long as we maintain that this process

     *       or thread is handling the backend

     */

    for (i = 0; i < dconf->raliases->nelts; i++, ralias++) {

        if (strcasecmp(backend, ralias->real) == 0) {

            ralias = NULL;

            break;

        }

    }

    /* Didn't find one... add it */

    if (!ralias) {

        ap_log_rerror(APLOG_MARK, APLOG_DEBUG, 0, r, APLOGNO(01006)

                      "proxy_express: adding PPR entry");

        ralias = apr_array_push(dconf->raliases);

        ralias->fake = "/";

        ralias->real = apr_pstrdup(dconf->raliases->pool, backend);

        ralias->flags = 0;

    }

    return OK;

}

static const command_rec command_table[] = {

    AP_INIT_FLAG("ProxyExpressEnable", set_enabled, NULL, OR_FILEINFO,

                 "Enable the ProxyExpress functionality"),

    AP_INIT_TAKE1("ProxyExpressDBMFile", set_dbmfile, NULL, OR_FILEINFO,

                  "Location of ProxyExpressDBMFile file"),

    AP_INIT_TAKE1("ProxyExpressDBMType", set_dbmtype, NULL, OR_FILEINFO,

                  "Type of ProxyExpressDBMFile file"),

    { NULL }

};

static void register_hooks(apr_pool_t *p)

{

    ap_hook_post_config(post_config, NULL, NULL, APR_HOOK_LAST);

    ap_hook_translate_name(xlate_name, NULL, NULL, APR_HOOK_FIRST);

}

/* the main config structure */

AP_DECLARE_MODULE(proxy_express) =

{

    STANDARD20_MODULE_STUFF,

    NULL,           /* create per-dir config structures */

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

    server_create,  /* create per-server config structures */

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

    command_table,  /* table of config file commands */

    register_hooks  /* register hooks */

};