plugin_rest_config.c

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/*
   This file is part of GNUnet.
   Copyright (C) 2012-2018 GNUnet e.V.

   GNUnet is free software: you can redistribute it and/or modify it
   under the terms of the GNU Affero General Public License as published
   by the Free Software Foundation, either version 3 of the License,
   or (at your option) any later version.

   GNUnet is distributed in the hope that it will be useful, but
   WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Affero General Public License for more details.

   You should have received a copy of the GNU Affero General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
#include "platform.h"
#include "gnunet_rest_plugin.h"
#include <gnunet_rest_lib.h>
#include <gnunet_util_lib.h>
#include <jansson.h>

#define GNUNET_REST_API_NS_CONFIG "/config"

struct Plugin {
  const struct GNUNET_CONFIGURATION_Handle *cfg;
};

const struct GNUNET_CONFIGURATION_Handle *cfg;

struct RequestHandle {
  struct GNUNET_REST_RequestHandle *rest_handle;

  GNUNET_REST_ResultProcessor proc;

  void *proc_cls;

  int response_code;

  char *url;
};


static void
cleanup_handle(struct RequestHandle *handle)
{
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Cleaning up\n");
  if (NULL != handle->url)
    GNUNET_free(handle->url);
  GNUNET_free(handle);
}


static void
do_error(void *cls)
{
  struct RequestHandle *handle = cls;
  struct MHD_Response *resp;

  resp = GNUNET_REST_create_response(NULL);
  handle->proc(handle->proc_cls, resp, handle->response_code);
  cleanup_handle(handle);
}


static void
add_sections(void *cls,
             const char *section,
             const char *option,
             const char *value)
{
  json_t *sections_obj = cls;
  json_t *sec_obj;

  sec_obj = json_object_get(sections_obj, section);
  if (NULL != sec_obj)
    {
      json_object_set_new(sec_obj, option, json_string(value));
      return;
    }
  sec_obj = json_object();
  json_object_set_new(sec_obj, option, json_string(value));
  json_object_set_new(sections_obj, section, sec_obj);
}

static void
add_section_contents(void *cls,
                     const char *section,
                     const char *option,
                     const char *value)
{
  json_t *section_obj = cls;

  json_object_set_new(section_obj, option, json_string(value));
}

static void
get_cont(struct GNUNET_REST_RequestHandle *con_handle,
         const char *url,
         void *cls)
{
  struct MHD_Response *resp;
  struct RequestHandle *handle = cls;
  const char *section;
  char *response;
  json_t *result;

  if (strlen(GNUNET_REST_API_NS_CONFIG) > strlen(handle->url))
    {
      handle->response_code = MHD_HTTP_BAD_REQUEST;
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }
  if (strlen(GNUNET_REST_API_NS_CONFIG) == strlen(handle->url))
    {
      result = json_object();
      GNUNET_CONFIGURATION_iterate(cfg, &add_sections, result);
    }
  else
    {
      result = json_object();
      section = &handle->url[strlen(GNUNET_REST_API_NS_CONFIG) + 1];
      GNUNET_CONFIGURATION_iterate_section_values(cfg,
                                                  section,
                                                  &add_section_contents,
                                                  result);
    }
  response = json_dumps(result, 0);
  resp = GNUNET_REST_create_response(response);
  handle->proc(handle->proc_cls, resp, MHD_HTTP_OK);
  cleanup_handle(handle);
  GNUNET_free(response);
  json_decref(result);
}

struct GNUNET_CONFIGURATION_Handle *
set_value(struct GNUNET_CONFIGURATION_Handle *config,
          const char *section,
          const char *option,
          json_t *value)
{
  if (json_is_string(value))
    GNUNET_CONFIGURATION_set_value_string(config, section, option, json_string_value(value));
  else if (json_is_number(value))
    GNUNET_CONFIGURATION_set_value_number(config, section, option, json_integer_value(value));
  else if (json_is_null(value))
    GNUNET_CONFIGURATION_set_value_string(config, section, option, NULL);
  else if (json_is_true(value))
    GNUNET_CONFIGURATION_set_value_string(config, section, option, "yes");
  else if (json_is_false(value))
    GNUNET_CONFIGURATION_set_value_string(config, section, option, "no");
  else
    return NULL;
  return config; // for error handling (0 -> success, 1 -> error)
}

static void
set_cont(struct GNUNET_REST_RequestHandle *con_handle,
         const char *url,
         void *cls)
{
  struct RequestHandle *handle = cls;
  char term_data[handle->rest_handle->data_size + 1];
  struct GNUNET_CONFIGURATION_Handle *out = GNUNET_CONFIGURATION_dup(cfg);

  json_error_t err;
  json_t *data_json;
  const char *section;
  const char *option;
  json_t *sec_obj;
  json_t *value;
  char *cfg_fn;

  // invalid url
  if (strlen(GNUNET_REST_API_NS_CONFIG) > strlen(handle->url))
    {
      handle->response_code = MHD_HTTP_BAD_REQUEST;
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }

  // extract data from handle
  term_data[handle->rest_handle->data_size] = '\0';
  GNUNET_memcpy(term_data,
                handle->rest_handle->data,
                handle->rest_handle->data_size);
  data_json = json_loads(term_data, JSON_DECODE_ANY, &err);

  if (NULL == data_json)
    {
      GNUNET_log(GNUNET_ERROR_TYPE_ERROR,
                 "Unable to parse JSON Object from %s\n",
                 term_data);
      GNUNET_SCHEDULER_add_now(&do_error, handle);
      return;
    }

  // POST /config => {<section> : {<option> : <value>}}
  if (strlen(GNUNET_REST_API_NS_CONFIG) == strlen(handle->url))   // POST /config
    {
      // iterate over sections
      json_object_foreach(data_json, section, sec_obj)
      {
        // iterate over options
        json_object_foreach(sec_obj, option, value)
        {
          out = set_value(out, section, option, value);
          if (NULL == out)
            {
              handle->response_code = MHD_HTTP_BAD_REQUEST;
              GNUNET_SCHEDULER_add_now(&do_error, handle);
              json_decref(data_json);
              return;
            }
        }
      }
    }
  else // POST /config/<section> => {<option> : <value>}
    {
      // extract the "<section>" part from the url
      section = &handle->url[strlen(GNUNET_REST_API_NS_CONFIG) + 1];
      // iterate over options
      json_object_foreach(data_json, option, value)
      {
        out = set_value(out, section, option, value);
        if (NULL == out)
          {
            handle->response_code = MHD_HTTP_BAD_REQUEST;
            GNUNET_SCHEDULER_add_now(&do_error, handle);
            json_decref(data_json);
            return;
          }
      }
    }
  json_decref(data_json);


  // get cfg file path
  cfg_fn = NULL;
  const char *xdg = getenv("XDG_CONFIG_HOME");
  if (NULL != xdg)
    GNUNET_asprintf(&cfg_fn,
                    "%s%s%s",
                    xdg,
                    DIR_SEPARATOR_STR,
                    GNUNET_OS_project_data_get()->config_file);
  else
    cfg_fn = GNUNET_strdup(GNUNET_OS_project_data_get()->user_config_file);

  GNUNET_CONFIGURATION_write(out, cfg_fn);
  cfg = out;
  handle->proc(handle->proc_cls,
               GNUNET_REST_create_response(NULL),
               MHD_HTTP_OK);
  cleanup_handle(handle);
}

static void
options_cont(struct GNUNET_REST_RequestHandle *con_handle,
             const char *url,
             void *cls)
{
  struct MHD_Response *resp;
  struct RequestHandle *handle = cls;

  resp = GNUNET_REST_create_response(NULL);
  MHD_add_response_header(resp,
                          "Access-Control-Allow-Methods",
                          MHD_HTTP_METHOD_GET);
  handle->proc(handle->proc_cls, resp, MHD_HTTP_OK);
  cleanup_handle(handle);
}


static void
rest_config_process_request(struct GNUNET_REST_RequestHandle *conndata_handle,
                            GNUNET_REST_ResultProcessor proc,
                            void *proc_cls)
{
  static const struct GNUNET_REST_RequestHandler handlers[] = {
    { MHD_HTTP_METHOD_GET, GNUNET_REST_API_NS_CONFIG, &get_cont },
    { MHD_HTTP_METHOD_POST, GNUNET_REST_API_NS_CONFIG, &set_cont },
    { MHD_HTTP_METHOD_OPTIONS, GNUNET_REST_API_NS_CONFIG, &options_cont },
    GNUNET_REST_HANDLER_END
  };
  struct RequestHandle *handle = GNUNET_new(struct RequestHandle);
  struct GNUNET_REST_RequestHandlerError err;

  handle->proc_cls = proc_cls;
  handle->proc = proc;
  handle->rest_handle = conndata_handle;
  handle->url = GNUNET_strdup(conndata_handle->url);
  if (handle->url[strlen(handle->url) - 1] == '/')
    handle->url[strlen(handle->url) - 1] = '\0';

  if (GNUNET_NO ==
      GNUNET_REST_handle_request(conndata_handle, handlers, &err, handle))
    {
      handle->response_code = err.error_code;
      GNUNET_SCHEDULER_add_now(&do_error, handle);
    }
}


void *
libgnunet_plugin_rest_config_init(void *cls)
{
  static struct Plugin plugin;

  cfg = cls;
  struct GNUNET_REST_Plugin *api;

  if (NULL != plugin.cfg)
    return NULL; /* can only initialize once! */
  memset(&plugin, 0, sizeof(struct Plugin));
  plugin.cfg = cfg;
  api = GNUNET_new(struct GNUNET_REST_Plugin);
  api->cls = &plugin;
  api->name = GNUNET_REST_API_NS_CONFIG;
  api->process_request = &rest_config_process_request;
  GNUNET_log(GNUNET_ERROR_TYPE_INFO, _("CONFIG REST API initialized\n"));
  return api;
}


void *
libgnunet_plugin_rest_config_done(void *cls)
{
  struct GNUNET_REST_Plugin *api = cls;
  struct Plugin *plugin = api->cls;

  plugin->cfg = NULL;
  GNUNET_free(api);
  GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "CONFIG REST plugin is finished\n");
  return NULL;
}

/* end of plugin_rest_config.c */