/*
This file is part of GNUnet.
Copyright (C) 2012-2015 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 .
*/
/**
* @author Martin Schanzenbach
* @author Philippe Buschmann
* @file namestore/plugin_rest_namestore.c
* @brief GNUnet Namestore REST plugin
*/
#include "platform.h"
#include "gnunet_rest_plugin.h"
#include "gnunet_gns_service.h"
#include "gnunet_namestore_service.h"
#include "gnunet_identity_service.h"
#include "gnunet_rest_lib.h"
#include "gnunet_json_lib.h"
#include "microhttpd.h"
#include
#define GNUNET_REST_API_NS_NAMESTORE "/namestore"
#define GNUNET_REST_SUBSYSTEM_NAMESTORE "namestore"
#define GNUNET_REST_JSON_NAMESTORE_RECORD_TYPE "record_type"
#define GNUNET_REST_JSON_NAMESTORE_VALUE "value"
#define GNUNET_REST_JSON_NAMESTORE_EXPIRATION "expiration"
#define GNUNET_REST_JSON_NAMESTORE_EXPIRED "expired"
#define GNUNET_REST_ERROR_UNKNOWN "Unknown Error"
#define GNUNET_REST_NAMESTORE_RD_COUNT 1
//TODO define other variables
/**
* The configuration handle
*/
const struct GNUNET_CONFIGURATION_Handle *cfg;
/**
* HTTP methods allows for this plugin
*/
static char* allow_methods;
/**
* @brief struct returned by the initialization function of the plugin
*/
struct Plugin
{
const struct GNUNET_CONFIGURATION_Handle *cfg;
};
//TODO add specific structs
/**
* The default namestore ego
*/
struct EgoEntry
{
/**
* Ego Identifier
*/
const char *identifier;
/**
* Public key string
*/
char *keystring;
/**
* The Ego
*/
struct GNUNET_IDENTITY_Ego *ego;
};
struct RequestHandle
{
//TODO add specific entries
/**
* Records to store
*/
char *label_name;
/**
* Records to store
*/
struct GNUNET_GNSRECORD_Data *rd;
/**
* NAMESTORE Operation
*/
struct GNUNET_NAMESTORE_QueueEntry *add_qe;
/**
* Response object
*/
json_t *resp_object;
/**
* Handle to NAMESTORE
*/
struct GNUNET_NAMESTORE_Handle *ns_handle;
/**
* Handle to NAMESTORE it
*/
struct GNUNET_NAMESTORE_ZoneIterator *list_it;
/**
* Private key for the zone
*/
struct GNUNET_CRYPTO_EcdsaPrivateKey zone_pkey;
/**
* IDENTITY Operation
*/
struct EgoEntry *ego_entry;
/**
* IDENTITY Operation
*/
struct GNUNET_IDENTITY_Operation *op;
/**
* Handle to Identity service.
*/
struct GNUNET_IDENTITY_Handle *identity_handle;
/**
* Rest connection
*/
struct GNUNET_REST_RequestHandle *rest_handle;
/**
* Desired timeout for the lookup (default is no timeout).
*/
struct GNUNET_TIME_Relative timeout;
/**
* ID of a task associated with the resolution process.
*/
struct GNUNET_SCHEDULER_Task *timeout_task;
/**
* The plugin result processor
*/
GNUNET_REST_ResultProcessor proc;
/**
* The closure of the result processor
*/
void *proc_cls;
/**
* The url
*/
char *url;
/**
* Error response message
*/
char *emsg;
/**
* Reponse code
*/
int response_code;
};
//TODO add specific cleanup
/**
* Cleanup lookup handle
* @param handle Handle to clean up
*/
static void
cleanup_handle (void *cls)
{
struct RequestHandle *handle = cls;
size_t index;
json_t *json_ego;
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Cleaning up\n");
if (NULL != handle->timeout_task)
{
GNUNET_SCHEDULER_cancel (handle->timeout_task);
handle->timeout_task = NULL;
}
if (NULL != handle->label_name)
GNUNET_free(handle->label_name);
if (NULL != handle->url)
GNUNET_free(handle->url);
if (NULL != handle->emsg)
GNUNET_free(handle->emsg);
if (NULL != handle->rd)
{
if (NULL != handle->rd->data)
GNUNET_free((void*)handle->rd->data);
GNUNET_free(handle->rd);
}
if (NULL != handle->timeout_task)
GNUNET_SCHEDULER_cancel(handle->timeout_task);
if (NULL != handle->list_it)
GNUNET_NAMESTORE_zone_iteration_stop(handle->list_it);
if (NULL != handle->add_qe)
GNUNET_NAMESTORE_cancel(handle->add_qe);
if (NULL != handle->identity_handle)
GNUNET_IDENTITY_disconnect(handle->identity_handle);
if (NULL != handle->ns_handle)
{
GNUNET_NAMESTORE_disconnect(handle->ns_handle);
}
if (NULL != handle->ego_entry)
{
if (NULL != handle->ego_entry->keystring)
GNUNET_free(handle->ego_entry->keystring);
GNUNET_free(handle->ego_entry);
}
if(NULL != handle->resp_object)
{
json_array_foreach(handle->resp_object, index, json_ego )
{
json_decref (json_ego);
}
json_decref(handle->resp_object);
}
GNUNET_free (handle);
}
/**
* Task run on errors. Reports an error and cleans up everything.
*
* @param cls the `struct RequestHandle`
*/
static void
do_error (void *cls)
{
struct RequestHandle *handle = cls;
struct MHD_Response *resp;
json_t *json_error = json_object();
char *response;
if (NULL == handle->emsg)
handle->emsg = GNUNET_strdup(GNUNET_REST_ERROR_UNKNOWN);
json_object_set_new(json_error,"error", json_string(handle->emsg));
if (0 == handle->response_code)
handle->response_code = MHD_HTTP_OK;
response = json_dumps (json_error, 0);
resp = GNUNET_REST_create_response (response);
handle->proc (handle->proc_cls, resp, handle->response_code);
json_decref(json_error);
GNUNET_free(response);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}
/**
* Does internal server error when iteration failed.
*/
static void
namestore_iteration_error (void *cls)
{
struct RequestHandle *handle = cls;
struct MHD_Response *resp = GNUNET_REST_create_response (NULL);
handle->response_code = MHD_HTTP_INTERNAL_SERVER_ERROR;
handle->proc (handle->proc_cls, resp, handle->response_code);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}
/**
* Create json representation of a GNSRECORD
*
* @param rd the GNSRECORD_Data
*/
static json_t *
gnsrecord_to_json (const struct GNUNET_GNSRECORD_Data *rd)
{
const char *typename;
char *string_val;
const char *exp_str;
json_t *record_obj;
typename = GNUNET_GNSRECORD_number_to_typename (rd->record_type);
string_val = GNUNET_GNSRECORD_value_to_string (rd->record_type,
rd->data,
rd->data_size);
if (NULL == string_val)
{
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Record of type %d malformed, skipping\n",
(int) rd->record_type);
return NULL;
}
record_obj = json_object();
json_object_set_new (record_obj,
GNUNET_REST_JSON_NAMESTORE_RECORD_TYPE,
json_string (typename));
json_object_set_new (record_obj,
GNUNET_REST_JSON_NAMESTORE_VALUE,
json_string (string_val));
//GNUNET_free (string_val);
if (GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION & rd->flags)
{
struct GNUNET_TIME_Relative time_rel;
time_rel.rel_value_us = rd->expiration_time;
exp_str = GNUNET_STRINGS_relative_time_to_string (time_rel, 1);
}
else
{
struct GNUNET_TIME_Absolute time_abs;
time_abs.abs_value_us = rd->expiration_time;
exp_str = GNUNET_STRINGS_absolute_time_to_string (time_abs);
}
json_object_set_new (record_obj,
GNUNET_REST_JSON_NAMESTORE_EXPIRATION,
json_string (exp_str));
json_object_set_new (record_obj, "expired",
json_boolean (GNUNET_YES == GNUNET_GNSRECORD_is_expired (rd)));
return record_obj;
}
static void
create_finished (void *cls, int32_t success, const char *emsg)
{
struct RequestHandle *handle = cls;
struct MHD_Response *resp;
handle->add_qe = NULL;
if (GNUNET_YES != success)
{
handle->emsg = GNUNET_strdup("Error storing records");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
resp = GNUNET_REST_create_response (NULL);
handle->proc (handle->proc_cls, resp, MHD_HTTP_NO_CONTENT);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}
/**
* Iteration over all results finished, build final
* response.
*
* @param cls the `struct RequestHandle`
*/
static void
namestore_list_finished (void *cls)
{
struct RequestHandle *handle = cls;
char *result_str;
struct MHD_Response *resp;
handle->list_it = NULL;
GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "HEY\n");
if (NULL == handle->resp_object)
{
GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "OH\n");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
result_str = json_dumps (handle->resp_object, 0);
GNUNET_log(GNUNET_ERROR_TYPE_DEBUG, "Result %s\n", result_str);
resp = GNUNET_REST_create_response (result_str);
handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
GNUNET_free_non_null (result_str);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
}
/**
* Create a response with requested records
*
* @param handle the RequestHandle
*/
static void
namestore_list_iteration (void *cls,
const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone_key,
const char *rname,
unsigned int rd_len,
const struct GNUNET_GNSRECORD_Data *rd)
{
struct RequestHandle *handle = cls;
json_t *record_obj;
if (NULL == handle->resp_object)
handle->resp_object = json_array();
char *result_str = json_dumps (handle->resp_object, 0);
GNUNET_log(GNUNET_ERROR_TYPE_ERROR, "%s\n", result_str);
GNUNET_free(result_str);
/*if ( (NULL != handle->ego_entry->identifier) &&
(0 != strcmp (handle->ego_entry->identifier,
rname)) )
{
GNUNET_log (GNUNET_ERROR_TYPE_ERROR,
"%s does not match %s\n", rname,
handle->ego_entry->identifier);
GNUNET_NAMESTORE_zone_iterator_next (handle->list_it, 1);
return;
}*/
for (unsigned int i = 0; i < rd_len; i++)
{
if ( (GNUNET_GNSRECORD_TYPE_NICK == rd[i].record_type) &&
(0 != strcmp (rname, GNUNET_GNS_EMPTY_LABEL_AT)) )
continue;
record_obj = gnsrecord_to_json (&rd[i]);
if(NULL == record_obj)
continue;
json_array_append (handle->resp_object,
record_obj);
json_decref (record_obj);
}
GNUNET_NAMESTORE_zone_iterator_next (handle->list_it, 1);
}
/**
* Handle namestore GET request
*
* @param con_handle the connection handle
* @param url the url
* @param cls the RequestHandle
*/
void
namestore_get (struct GNUNET_REST_RequestHandle *con_handle,
const char* url,
void *cls)
{
struct RequestHandle *handle = cls;
if (strlen (GNUNET_REST_API_NS_NAMESTORE) != strlen (handle->url))
{
handle->emsg = GNUNET_strdup("Wrong URL");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
handle->list_it = GNUNET_NAMESTORE_zone_iteration_start (handle->ns_handle,
&handle->zone_pkey,
&namestore_iteration_error,
handle,
&namestore_list_iteration,
handle,
&namestore_list_finished,
handle);
}
/*
//TODO filter input
static int
json_to_gnsrecord (struct RequestHandle *handle)
{
struct GNUNET_TIME_Relative etime_rel;
struct GNUNET_TIME_Absolute etime_abs;
void *rdata;
size_t rdata_size;
handle->rd = GNUNET_new_array(GNUNET_REST_NAMESTORE_RD_COUNT,
struct GNUNET_GNSRECORD_Data);
memset (handle->rd, 0, sizeof(struct GNUNET_GNSRECORD_Data));
handle->rd->record_type = GNUNET_GNSRECORD_typename_to_number (
handle->json_data->type);
if (UINT32_MAX == (*handle->rd).record_type)
{
handle->emsg = GNUNET_strdup("Unsupported type");
return GNUNET_SYSERR;
}
if (GNUNET_OK
!= GNUNET_GNSRECORD_string_to_value ((*handle->rd).record_type,
handle->json_data->value, &rdata,
&rdata_size))
{
handle->emsg = GNUNET_strdup("Value invalid for record type");
return GNUNET_SYSERR;
}
(*handle->rd).data = rdata;
(*handle->rd).data_size = rdata_size;
//TODO other flags
if (0 == handle->json_data->is_public)
{
handle->rd->flags |= GNUNET_GNSRECORD_RF_PRIVATE;
}
/**TODO
* if (1 == handle->is_shadow)
rde->flags |= GNUNET_GNSRECORD_RF_SHADOW_RECORD;
if (1 != handle->is_public)
rde->flags |= GNUNET_GNSRECORD_RF_PRIVATE;
*
if (0 == strcmp (handle->json_data->expiration_time, "never"))
{
(*handle->rd).expiration_time = GNUNET_TIME_UNIT_FOREVER_ABS.abs_value_us;
}
else if (GNUNET_OK
== GNUNET_STRINGS_fancy_time_to_relative (
handle->json_data->expiration_time, &etime_rel))
{
(*handle->rd).expiration_time = etime_rel.rel_value_us;
(*handle->rd).flags |= GNUNET_GNSRECORD_RF_RELATIVE_EXPIRATION;
}
else if (GNUNET_OK
== GNUNET_STRINGS_fancy_time_to_absolute (
handle->json_data->expiration_time, &etime_abs))
{
(*handle->rd).expiration_time = etime_abs.abs_value_us;
}
else
{
handle->emsg = GNUNET_strdup("Value invalid for record type");
return GNUNET_SYSERR;
}
return GNUNET_OK;
}
*/
/**
* We're storing a new record; this requires
* that no record already exists
*
* @param cls closure, unused
* @param zone_key private key of the zone
* @param rec_name name that is being mapped (at most 255 characters long)
* @param rd_count number of entries in @a rd array
* @param rd array of records with data to store
*/
static void
create_new_record_cont (void *cls,
const struct GNUNET_CRYPTO_EcdsaPrivateKey *zone_key,
const char *rec_name,
unsigned int rd_count,
const struct GNUNET_GNSRECORD_Data *rd)
{
struct RequestHandle *handle = cls;
handle->add_qe = NULL;
if (0 != strcmp (rec_name, handle->label_name))
{
GNUNET_break (0);
do_error (handle);
return;
}
if (0 != rd_count)
{
handle->proc (handle->proc_cls,
GNUNET_REST_create_response (NULL),
MHD_HTTP_CONFLICT);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
return;
}
handle->add_qe = GNUNET_NAMESTORE_records_store (handle->ns_handle,
&handle->zone_pkey,
handle->label_name,
GNUNET_REST_NAMESTORE_RD_COUNT,
handle->rd,
&create_finished,
handle);
}
/**
* Handle namestore POST request
*
* @param con_handle the connection handle
* @param url the url
* @param cls the RequestHandle
*/
void
namestore_add (struct GNUNET_REST_RequestHandle *con_handle,
const char* url,
void *cls)
{
struct RequestHandle *handle = cls;
struct GNUNET_GNSRECORD_Data *gns_record;
json_t *data_js;
json_t *name_json;
json_error_t err;
char term_data[handle->rest_handle->data_size + 1];
struct GNUNET_JSON_Specification gnsspec[] = {
GNUNET_JSON_spec_gnsrecord_data(&gns_record),
GNUNET_JSON_spec_end ()
};
if (strlen (GNUNET_REST_API_NS_NAMESTORE) != strlen (handle->url))
{
handle->emsg = GNUNET_strdup("Wrong URL");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
if (0 >= handle->rest_handle->data_size)
{
handle->emsg = GNUNET_strdup("No data");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
term_data[handle->rest_handle->data_size] = '\0';
GNUNET_memcpy(term_data, handle->rest_handle->data,
handle->rest_handle->data_size);
data_js = json_loads (term_data, JSON_DECODE_ANY, &err);
GNUNET_assert (GNUNET_OK == GNUNET_JSON_parse (data_js, gnsspec, NULL, NULL));
name_json = json_object_get(data_js, "label");
if (!json_is_string(name_json))
{
handle->emsg = GNUNET_strdup("Missing name");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
handle->label_name = GNUNET_strdup(json_string_value(name_json));
if(NULL == handle->label_name)
{
handle->emsg = GNUNET_strdup("Missing name");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
json_decref (data_js);
handle->rd = gns_record;
handle->add_qe = GNUNET_NAMESTORE_records_lookup (handle->ns_handle,
&handle->zone_pkey,
handle->label_name,
&do_error,
handle,
&create_new_record_cont,
handle);
}
/**
* Handle namestore DELETE request
*
* @param con_handle the connection handle
* @param url the url
* @param cls the RequestHandle
*/
void
namestore_delete (struct GNUNET_REST_RequestHandle *con_handle,
const char* url,
void *cls)
{
struct RequestHandle *handle = cls;
//TODO add behaviour and response
handle->emsg = GNUNET_strdup ("Not implemented yet");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
/**
* Respond to OPTIONS request
*
* @param con_handle the connection handle
* @param url the url
* @param cls the RequestHandle
*/
static void
options_cont (struct GNUNET_REST_RequestHandle *con_handle,
const char* url,
void *cls)
{
struct MHD_Response *resp;
struct RequestHandle *handle = cls;
//independent of path return all options
resp = GNUNET_REST_create_response (NULL);
MHD_add_response_header (resp,
"Access-Control-Allow-Methods",
allow_methods);
handle->proc (handle->proc_cls, resp, MHD_HTTP_OK);
GNUNET_SCHEDULER_add_now (&cleanup_handle, handle);
return;
}
/**
* Handle rest request
*
* @param handle the request handle
*/
static void
init_cont (struct RequestHandle *handle)
{
//TODO specify parameter of init_cont if necessary
struct GNUNET_REST_RequestHandlerError err;
static const struct GNUNET_REST_RequestHandler handlers[] = {
{MHD_HTTP_METHOD_GET, GNUNET_REST_API_NS_NAMESTORE, &namestore_get},
{MHD_HTTP_METHOD_POST, GNUNET_REST_API_NS_NAMESTORE, &namestore_add},
{MHD_HTTP_METHOD_DELETE, GNUNET_REST_API_NS_NAMESTORE, &namestore_delete},
{MHD_HTTP_METHOD_OPTIONS, GNUNET_REST_API_NS_NAMESTORE, &options_cont},
GNUNET_REST_HANDLER_END
};
if (GNUNET_NO == GNUNET_REST_handle_request (handle->rest_handle,
handlers,
&err,
handle))
{
handle->response_code = err.error_code;
GNUNET_SCHEDULER_add_now (&do_error, handle);
}
}
/**
*
*/
static void
default_ego_cb (void *cls,
struct GNUNET_IDENTITY_Ego *ego,
void **ctx,
const char *name)
{
struct RequestHandle *handle = cls;
struct EgoEntry *ego_entry;
struct GNUNET_CRYPTO_EcdsaPublicKey pk;
handle->op = NULL;
if (NULL == ego)
{
handle->emsg = GNUNET_strdup ("No default ego configured in identity service");
GNUNET_SCHEDULER_add_now (&do_error, handle);
return;
}
ego_entry = GNUNET_new(struct EgoEntry);
GNUNET_IDENTITY_ego_get_public_key (ego, &pk);
ego_entry->keystring = GNUNET_CRYPTO_ecdsa_public_key_to_string (&pk);
ego_entry->identifier = name;
ego_entry->ego = ego;
handle->ego_entry = ego_entry;
handle->zone_pkey = *GNUNET_IDENTITY_ego_get_private_key (ego);
init_cont (handle);
}
/**
* Connect to identity callback
*/
static void
id_connect_cb (void *cls,
struct GNUNET_IDENTITY_Ego *ego,
void **ctx,
const char *name)
{
struct RequestHandle *handle = cls;
if (NULL == ego)
{
handle->op = GNUNET_IDENTITY_get (handle->identity_handle,
GNUNET_REST_SUBSYSTEM_NAMESTORE,
&default_ego_cb,
handle);
}
}
/**
* Function processing the REST call
*
* @param method HTTP method
* @param url URL of the HTTP request
* @param data body of the HTTP request (optional)
* @param data_size length of the body
* @param proc callback function for the result
* @param proc_cls closure for callback function
* @return GNUNET_OK if request accepted
*/
static void
rest_process_request(struct GNUNET_REST_RequestHandle *rest_handle,
GNUNET_REST_ResultProcessor proc,
void *proc_cls)
{
struct RequestHandle *handle = GNUNET_new (struct RequestHandle);
handle->response_code = 0;
handle->timeout = GNUNET_TIME_UNIT_FOREVER_REL;
handle->proc_cls = proc_cls;
handle->proc = proc;
handle->rest_handle = rest_handle;
handle->url = GNUNET_strdup (rest_handle->url);
if (handle->url[strlen (handle->url)-1] == '/')
handle->url[strlen (handle->url)-1] = '\0';
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connecting...\n");
handle->identity_handle = GNUNET_IDENTITY_connect (cfg, &id_connect_cb, handle);
handle->ns_handle = GNUNET_NAMESTORE_connect (cfg);
handle->timeout_task =
GNUNET_SCHEDULER_add_delayed (handle->timeout,
&do_error,
handle);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Connected\n");
}
/**
* Entry point for the plugin.
*
* @param cls Config info
* @return NULL on error, otherwise the plugin context
*/
void *
libgnunet_plugin_rest_namestore_init (void *cls)
{
static struct Plugin plugin;
struct GNUNET_REST_Plugin *api;
cfg = cls;
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_NAMESTORE;
api->process_request = &rest_process_request;
GNUNET_asprintf (&allow_methods,
"%s, %s, %s, %s, %s",
MHD_HTTP_METHOD_GET,
MHD_HTTP_METHOD_POST,
MHD_HTTP_METHOD_PUT,
MHD_HTTP_METHOD_DELETE,
MHD_HTTP_METHOD_OPTIONS);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
_("Namestore REST API initialized\n"));
return api;
}
/**
* Exit point from the plugin.
*
* @param cls the plugin context (as returned by "init")
* @return always NULL
*/
void *
libgnunet_plugin_rest_namestore_done (void *cls)
{
struct GNUNET_REST_Plugin *api = cls;
struct Plugin *plugin = api->cls;
plugin->cfg = NULL;
GNUNET_free_non_null (allow_methods);
GNUNET_free (api);
GNUNET_log (GNUNET_ERROR_TYPE_DEBUG,
"Namestore REST plugin is finished\n");
return NULL;
}
/* end of plugin_rest_namestore.c */