/* 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 "apr.h"

#include "apr_strings.h"

#if APR_HAVE_STDLIB_H

#include <stdlib.h>

#endif

#include "ap_config.h"

#include "httpd.h"

#include "http_config.h"

#include "http_request.h"

#include "http_log.h"

typedef struct {

    apr_table_t *vars;

    apr_table_t *unsetenv;

} env_dir_config_rec;

module AP_MODULE_DECLARE_DATA env_module;

static void *create_env_dir_config(apr_pool_t *p, char *dummy)

{

    env_dir_config_rec *conf = apr_palloc(p, sizeof(*conf));

    conf->vars = apr_table_make(p, 10);

    conf->unsetenv = apr_table_make(p, 10);

    return conf;

}

static void *merge_env_dir_configs(apr_pool_t *p, void *basev, void *addv)

{

    env_dir_config_rec *base = basev;

    env_dir_config_rec *add = addv;

    env_dir_config_rec *res = apr_palloc(p, sizeof(*res));

    const apr_table_entry_t *elts;

    const apr_array_header_t *arr;

    int i;

    /*

     * res->vars = copy_table( p, base->vars );

     * foreach $unsetenv ( @add->unsetenv )

     *     table_unset( res->vars, $unsetenv );

     * foreach $element ( @add->vars )

     *     table_set( res->vars, $element.key, $element.val );

     *

     * add->unsetenv already removed the vars from add->vars,

     * if they preceded the UnsetEnv directive.

     */

    res->vars = apr_table_copy(p, base->vars);

    res->unsetenv = NULL;

    arr = apr_table_elts(add->unsetenv);

    if (arr) {

        elts = (const apr_table_entry_t *)arr->elts;

        for (i = 0; i < arr->nelts; ++i) {

            apr_table_unset(res->vars, elts[i].key);

        }

    }

    arr = apr_table_elts(add->vars);

    if (arr) {

        elts = (const apr_table_entry_t *)arr->elts;

        for (i = 0; i < arr->nelts; ++i) {

            apr_table_setn(res->vars, elts[i].key, elts[i].val);

        }

    }

    return res;

}

static const char *add_env_module_vars_passed(cmd_parms *cmd, void *sconf_,

                                              const char *arg)

{

    env_dir_config_rec *sconf = sconf_;

    apr_table_t *vars = sconf->vars;

    const char *env_var;

    env_var = getenv(arg);

    if (env_var != NULL) {

        apr_table_setn(vars, arg, apr_pstrdup(cmd->pool, env_var));

    }

    else {

        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(01506)

                     "PassEnv variable %s was undefined", arg);

    }

    return NULL;

}

static const char *add_env_module_vars_set(cmd_parms *cmd, void *sconf_,

                                           const char *name, const char *value)

{

    env_dir_config_rec *sconf = sconf_;

    if (ap_strchr_c(name, '=')) {

        char *env, *plast;

        env = apr_strtok(apr_pstrdup(cmd->temp_pool, name), "=", &plast);

        ap_log_error(APLOG_MARK, APLOG_WARNING, 0, cmd->server, APLOGNO(10032)

                     "Spurious usage of '=' in an environment variable name. "

                     "'%s %s %s' expected instead?", cmd->cmd->name, env, plast);

    }

    /* name is mandatory, value is optional.  no value means

     * set the variable to an empty string

     */

    apr_table_setn(sconf->vars, name, value ? value : "");

    return NULL;

}

static const char *add_env_module_vars_unset(cmd_parms *cmd, void *sconf_,

                                             const char *arg)

{

    env_dir_config_rec *sconf = sconf_;

    /* Always UnsetEnv FOO in the same context as {Set,Pass}Env FOO

     * only if this UnsetEnv follows the {Set,Pass}Env.  The merge

     * will only apply unsetenv to the parent env (main server).

     */

    apr_table_set(sconf->unsetenv, arg, NULL);

    apr_table_unset(sconf->vars, arg);

    return NULL;

}

static const command_rec env_module_cmds[] =

{

AP_INIT_ITERATE("PassEnv", add_env_module_vars_passed, NULL,

     OR_FILEINFO, "a list of environment variables to pass to CGI."),

AP_INIT_TAKE12("SetEnv", add_env_module_vars_set, NULL,

     OR_FILEINFO, "an environment variable name and optional value to pass to CGI."),

AP_INIT_ITERATE("UnsetEnv", add_env_module_vars_unset, NULL,

     OR_FILEINFO, "a list of variables to remove from the CGI environment."),

    {NULL},

};

static int fixup_env_module(request_rec *r)

{

    env_dir_config_rec *sconf = ap_get_module_config(r->per_dir_config,

                                                     &env_module);

    if (apr_is_empty_table(sconf->vars)) {

        return DECLINED;

    }

    r->subprocess_env = apr_table_overlay(r->pool, r->subprocess_env,

            sconf->vars);

    return OK;

}

static void register_hooks(apr_pool_t *p)

{

    ap_hook_fixups(fixup_env_module, NULL, NULL, APR_HOOK_MIDDLE);

}

AP_DECLARE_MODULE(env) =

{

    STANDARD20_MODULE_STUFF,

    create_env_dir_config,      /* dir config creater */

    merge_env_dir_configs,      /* dir merger --- default is to override */

    NULL,                       /* server config */

    NULL,                       /* merge server configs */

    env_module_cmds,            /* command apr_table_t */

    register_hooks              /* register hooks */

};