path: root/plugins/afm-main-plugin/utils-sbus.c

/*
 Copyright 2015 IoT.bzh

 author: José Bollo <jose.bollo@iot.bzh>

 Licensed 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.
*/
#define _GNU_SOURCE

#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <string.h>
#include <poll.h>
#include <assert.h>

#include <dbus/dbus.h>

#include "utils-sbus.h"

/*
 * errors messages generated by sbus
 */
static const char invalid_request_string[] = "invalid request";
static const char out_of_memory_string[] = "out of memory";

/*
 * structure for handled messages
 */
struct sbusmsg {
	DBusMessage *message;       /* message of the message */
	DBusConnection *connection; /* connection of the message */
};

/*
 * structure for services
 */
struct sbus_service {
	struct sbus_service *next;	/* link to the next service */
	char *destination;		/* destination for the service */
	char *path;		/* path for the service */
	char *iface;		/* iface for the service */
	char *member;		/* member for the service */
	void (*oncall) (struct sbusmsg *, const char *, void *);
				/* callback */
	void *closure;		/* closure for the callbacks */
};

/*
 * structure for signals
 */
struct sbus_signal {
	struct sbus_signal *next;	/* link to the next signal */
	char *sender;		/* expected sender of the signal */
	char *path;		/* expected path of the signal */
	char *iface;		/* expected iface of the signal */
	char *member;		/* expected member of the signal */
	void (*onsignal) (const struct sbusmsg *, const char *, void *);
				/* callback */
	void *closure;		/* closure for the callbacks */
};

/*
 * structure for asynchronous requests (resp-onse w-aiter)
 */
struct srespw {
	struct srespw *next;	/* next asynchronous */
	dbus_uint32_t serial;	/* serial dbus number */
	void *closure;		/* closure for the callbacks */
	void (*onresp) (int, const char *, void *);
				/* callback */
};

/*
 * structure for synchronous calls
 */
struct respsync {
	int replied;	/* boolean flag indicating reply */
	int status;     /* received status */
	char *value;	/* copy of the returned value */
};

/*
 * structure for handling either client or server sbus on dbus
 */
struct sbus {
	int refcount;			/* referenced how many time */
	DBusConnection *connection;	/* connection to DBU */
	const struct sbus_itf *itf;	/* interface to the main loop */
	void *itfclo;
	struct sbus_service *services;	/* first service */
	struct sbus_signal *signals;	/* first signal */
	struct srespw *waiters;		/* first response waiter */
	
};

static struct sbus system_sbus;
static struct sbus session_sbus;

/*********************** STATIC COMMON METHODS *****************/

/*
 * Frees the ressources attached to a message
 */
static inline void free_sbusmsg(struct sbusmsg *smsg)
{
	dbus_message_unref(smsg->message);
	dbus_connection_unref(smsg->connection);
	free(smsg);
}

/*
 * Replies the error "out of memory".
 * This function is intended to be used in services when an
 * allocation fails. Thus, it set errno to ENOMEM and
 * returns -1.
 */
static inline int reply_out_of_memory(struct sbusmsg *smsg)
{
	sbus_reply_error(smsg, out_of_memory_string);
	errno = ENOMEM;
	return -1;
}

/*
 * Checks if the incoming 'message' matches the interface
 * linked to 'sbus'.
 *
 * Returns 1 if it matches or 0 wether it does not matches.
 */
/*
static int matchitf(struct sbus *sbus, DBusMessage * message)
{
	const char *itf = dbus_message_get_interface(message);
	return itf != NULL && !strcmp(itf, sbus->name);
}
*/

/*
 * Callback function for synchronous calls.
 * This function fills the respsync structure pointed by 'data'
 * with the copy of the answer.
 */
static void sync_of_replies(int status, const char *value, struct respsync *s)
{
	s->status = status;
	s->value = status ? NULL : strdup(value ? value : "");
	s->replied = 1;
}

/*
 * Creates and returns the rule for 'signal'.
 */
static char *rule_of_signal(struct sbus_signal *signal)
{
	char *rule;
	return asprintf(&rule,
			"type='signal%s%s%s%s%s%s%s%s'",
			signal->sender ? "',sender='" : "",
				signal->sender ? signal->sender : "",
			signal->path   ? "',path='" : "",
				signal->path   ? signal->path : "",
			signal->iface  ? "',interface='" : "",
				signal->iface  ? signal->iface : "",
			signal->member  ? "',member='" : "",
				signal->member  ? signal->member : ""
		) < 0 ? NULL : rule;
}

/*********************** STATIC DBUS MESSAGE HANDLING *****************/

/*
 * Handles incomming responses 'message' on 'sbus'. Response are
 * either expected if 'iserror' == 0 or errors if 'iserror' != 0.
 *
 * Returns DBUS_HANDLER_RESULT_HANDLED or DBUS_HANDLER_RESULT_NOT_YET_HANDLED
 * as defined by the dbus function 'dbus_connection_add_filter'.
 */
static DBusHandlerResult incoming_resp(
		struct sbus *sbus,
		DBusMessage * message,
		int iserror)
{
	int status;
	const char *str;
	struct srespw *jrw, **prv;
	dbus_uint32_t serial;

	/* search for the waiter */
	serial = dbus_message_get_reply_serial(message);
	prv = &sbus->waiters;
	while ((jrw = *prv) != NULL) {
		if (jrw->serial == serial)
			goto found;
		prv = &jrw->next;
	}
	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

	/* treat it */
 found:
	*prv = jrw->next;
	if (jrw->onresp) {
		/* retrieve the string value */
		if (dbus_message_get_args
		    (message, NULL, DBUS_TYPE_STRING, &str, DBUS_TYPE_INVALID))
			status = 0;
		else {
			status = -1;
			str = NULL;
		}
		/* call now */
		jrw->onresp(iserror ? -1 : status, str, jrw->closure);
	}
	free(jrw);
	return DBUS_HANDLER_RESULT_HANDLED;
}

/*
 * Handles incomming on 'sbus' method calls for 'message'.
 *
 * Returns DBUS_HANDLER_RESULT_HANDLED or DBUS_HANDLER_RESULT_NOT_YET_HANDLED
 * as defined by the dbus function 'dbus_connection_add_filter'.
 */
static DBusHandlerResult incoming_call(
		struct sbus *sbus,
		DBusMessage * message)
{
	struct sbus_service *service;
	struct sbusmsg *smsg;
	const char *str;

	/* search for the service */
	service = sbus->services;
	while (service != NULL) {
		if ((service->destination == NULL || !strcmp(service->destination, dbus_message_get_destination(message)))
		 && (service->path == NULL || !strcmp(service->path, dbus_message_get_path(message)))
		 && (service->iface == NULL || !strcmp(service->iface, dbus_message_get_interface(message)))
		 && (service->member == NULL || !strcmp(service->member, dbus_message_get_member(message))))
			goto found;
		service = service->next;
	}
	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;

 found:
	/* creates and init the smsg structure */
	smsg = malloc(sizeof *smsg);
	if (smsg == NULL)
		return DBUS_HANDLER_RESULT_NEED_MEMORY;
	smsg->message = dbus_message_ref(message);
	smsg->connection = dbus_connection_ref(sbus->connection);

	/* retrieve the string parameter of the message */
	if (!dbus_message_get_args
	    (message, NULL, DBUS_TYPE_STRING, &str, DBUS_TYPE_INVALID))
		goto invalid_request;

	/* handling strings only */
	service->oncall(smsg, str, service->closure);
	return DBUS_HANDLER_RESULT_HANDLED;

invalid_request:
	sbus_reply_error(smsg, invalid_request_string);
	return DBUS_HANDLER_RESULT_HANDLED;
}

/*
 * Handles incomming on 'sbus' signal propagated with 'message'.
 *
 * This is a design choice to ignore invalid signals.
 *
 * Returns DBUS_HANDLER_RESULT_HANDLED or DBUS_HANDLER_RESULT_NOT_YET_HANDLED
 * as defined by the dbus function 'dbus_connection_add_filter'.
 */
static DBusHandlerResult incoming_signal(
		struct sbus *sbus,
		DBusMessage * message)
{
	DBusHandlerResult result;
	struct sbus_signal *signal;
	struct sbusmsg smsg;
	const char *str;

	/* retrieve the string value */
	result = DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
	if (!dbus_message_get_args(message, NULL,
				DBUS_TYPE_STRING, &str, DBUS_TYPE_INVALID))
		goto end;

	/* search a handler */
	smsg.message = message;
	smsg.connection = NULL;
	signal = sbus->signals;
	while (signal != NULL) {
		if ((signal->path == NULL || !strcmp(signal->path, dbus_message_get_path(message)))
		 && (signal->iface == NULL || !strcmp(signal->iface, dbus_message_get_interface(message)))
		 && (signal->member == NULL || !strcmp(signal->member, dbus_message_get_member(message)))) {
			signal->onsignal(&smsg, str, signal->closure);
			result = DBUS_HANDLER_RESULT_HANDLED;
		}
		signal = signal->next;
	}
 end:
	return result;
}

/*
 * Filters incomming messages as defined by the dbus function
 * 'dbus_connection_add_filter'.
 * Returns DBUS_HANDLER_RESULT_HANDLED or DBUS_HANDLER_RESULT_NOT_YET_HANDLED.
 */
static DBusHandlerResult incoming(
		DBusConnection * connection,
		DBusMessage * message,
		struct sbus *sbus)
{
	switch (dbus_message_get_type(message)) {
	case DBUS_MESSAGE_TYPE_METHOD_CALL:
		return incoming_call(sbus, message);
	case DBUS_MESSAGE_TYPE_METHOD_RETURN:
		return incoming_resp(sbus, message, 0);
	case DBUS_MESSAGE_TYPE_ERROR:
		return incoming_resp(sbus, message, 1);
	case DBUS_MESSAGE_TYPE_SIGNAL:
		return incoming_signal(sbus, message);
	}
	return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
}

/*********************** STATIC DBUS WATCH/POLLING INTERFACE **********/

struct swatch {
	DBusConnection *connection;
	DBusWatch *watch;
	void *hndl;
};

static void on_hangup(struct swatch *s)
{
	dbus_watch_handle(s->watch, DBUS_WATCH_HANGUP);
	while (dbus_connection_dispatch(s->connection) == DBUS_DISPATCH_DATA_REMAINS);
}

static void on_readable(struct swatch *s)
{
	dbus_watch_handle(s->watch, DBUS_WATCH_READABLE);
	while (dbus_connection_dispatch(s->connection) == DBUS_DISPATCH_DATA_REMAINS);
}

static void on_writable(struct swatch *s)
{
	dbus_watch_handle(s->watch, DBUS_WATCH_WRITABLE);
	while (dbus_connection_dispatch(s->connection) == DBUS_DISPATCH_DATA_REMAINS);
}

/*
 * DBUS Callback for removing a 'watch'.
 * See function 'dbus_connection_set_watch_functions'
 */
static void watchdel(DBusWatch *watch, struct sbus *sbus)
{
	struct swatch *s = dbus_watch_get_data(watch);
	sbus->itf->close(s->hndl);
	free(s);
}

/*
 * DBUS Callback for changing a 'watch'.
 * See function 'dbus_connection_set_watch_functions'
 */
static void watchtoggle(DBusWatch *watch, struct sbus *sbus)
{
	struct swatch *s = dbus_watch_get_data(watch);
	int enabled = (int)dbus_watch_get_enabled(watch);
	unsigned int flags = dbus_watch_get_flags(watch);
	if (flags & DBUS_WATCH_READABLE)
		sbus->itf->on_readable(s->hndl, enabled ? (void*)on_readable : NULL);
	if (flags & DBUS_WATCH_WRITABLE)
		sbus->itf->on_writable(s->hndl, enabled ? (void*)on_writable : NULL);
}


/*
 * DBUS Callback for adding a 'watch'.
 * See function 'dbus_connection_set_watch_functions'
 */
static dbus_bool_t watchadd(DBusWatch *watch, struct sbus *sbus)
{
	int fd;
	struct swatch *s;

	s = malloc(sizeof *s);
	if (s == NULL)
		goto error;
	fd = dbus_watch_get_unix_fd(watch);
	s->hndl = sbus->itf->open(fd, s, sbus->itfclo);
	if (s->hndl == NULL)
		goto error2;
	s->watch = watch;
	s->connection = sbus->connection;
	dbus_watch_set_data(watch, s, NULL);
	sbus->itf->on_hangup(s->hndl, (void*)on_hangup);
	watchtoggle(watch, sbus);
	return TRUE;
 error2:
	free(s);
 error:
	return FALSE;
}

/*
 * Creates a 'sbus' bound the 'path' and it derived names and linked
 * either to the DBUS SYSTEM when 'session' is nul or to the DBUS SESSION
 * if 'session' is not nul.
 *
 * The parameter 'path' is intended to be the path of a DBUS single object.
 * Single means that it exists only one instance of the object on the
 * given bus. That path implies 2 derived DBUS names:
 *   1. the destination name of the program that handles the object
 *   2. the interface name of the object
 * These names are derived by removing the heading slash (/) and
 * by replacing all occurences of slashes by dots.
 * For example, passing path = /a/b/c means that the object /a/b/c is
 * handled by the destination a.b.c and replies to the interface a.b.c
 *
 * Returns the created sbus or NULL in case of error.
 */
static struct sbus *get_sbus(const struct sbus_itf *itf, void *itfclo, struct sbus *sbus)
{
	/* create the sbus object */
	if (sbus->refcount > 0) {
		if (itf != sbus->itf)
			goto error;
		goto success;
	}

	/* connect and init */
	sbus->connection = dbus_bus_get(sbus == &session_sbus ? DBUS_BUS_SESSION
						: DBUS_BUS_SYSTEM, NULL);
	if (sbus->connection == NULL)
		goto error;

	sbus->itf = itf;
	sbus->itfclo = itfclo;
	if (!dbus_connection_add_filter(sbus->connection, (void*)incoming, sbus, NULL)
	 || !dbus_connection_set_watch_functions(sbus->connection, (void*)watchadd,
					(void*)watchdel, (void*)watchtoggle, sbus, NULL)) 
		goto error2;

 success:
	sbus->refcount++;
	return sbus;

 error2:
	dbus_connection_unref(sbus->connection);
	sbus->connection = NULL;
 error:
	return NULL;
}

/********************* MAIN FUNCTIONS *****************************************/

/*
 * Creates a 'sbus' bound to DBUS system using 'path' and returns it.
 * See 'create_sbus'
 */
struct sbus *sbus_system(const struct sbus_itf *itf, void *itfclo)
{
	return get_sbus(itf, itfclo, &system_sbus);
}

/*
 * Creates a 'sbus' bound to DBUS session using 'path' and returns it.
 * See 'create_sbus'
 */
struct sbus *sbus_session(const struct sbus_itf *itf, void *itfclo)
{
	return get_sbus(itf, itfclo, &session_sbus);
}

/*
 * Adds one reference to 'sbus'.
 */
void sbus_addref(struct sbus *sbus)
{
	sbus->refcount++;
}

/*
 * Removes one reference to 'sbus'. Destroys 'sbus' and it related
 * data if the count of references decrease to zero.
 */
void sbus_unref(struct sbus *sbus)
{
	struct srespw *w;
	if (!--sbus->refcount) {
		while (sbus->services != NULL)
			sbus_remove_service(sbus, sbus->services);
		while (sbus->signals != NULL)
			sbus_remove_signal(sbus, sbus->signals);
		if (sbus->connection != NULL) {
			dbus_connection_unref(sbus->connection);
			sbus->connection = NULL;
		}
		while ((w = sbus->waiters)) {
			sbus->waiters = w->next;
			if (w->onresp)
				w->onresp(-1, "cancelled", w->closure);
			free(w);
		}
	}
}

/*
 * Sends from 'sbus' the signal of 'member' handling the string 'content'.
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_send_signal(struct sbus *sbus, const char *sender, const char *path, const char *iface, const char *member, const char *content)
{
	int rc = -1;
	DBusMessage *message;

	message = dbus_message_new_signal(path, iface, member);
	if (message == NULL)
		goto error;

	if (sender != NULL && !dbus_message_set_sender(message, sender))
		goto error2;

	if (!dbus_message_append_args(message, DBUS_TYPE_STRING, &content,
					 DBUS_TYPE_INVALID))
		goto error2;

	if (dbus_connection_send(sbus->connection, message, NULL))
		rc = 0;

	dbus_message_unref(message);
	return rc;

 error2:
	dbus_message_unref(message);

 error:
	errno = ENOMEM;
	return -1;
}

/*
 * Asynchronous call to 'method' of 'sbus' passing the string 'query'.
 * On response, the function 'onresp' is called with the returned string
 * value and the closure 'closure'.
 * The function 'onresp' is invoked with 3 parameters:
 *   1. int: 0 if no error or -1 if error.
 *   2. const char *: the returned string (might be NULL if error)
 *   3. void *: the closure 'closure'
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_call(
		struct sbus *sbus,
		const char *destination,
		const char *path,
		const char *iface,
		const char *method,
		const char *query,
		void (*onresp) (int, const char *, void *),
		void *closure)
{
	DBusMessage *msg;
	struct srespw *resp;

	/* allocates the response structure */
	resp = malloc(sizeof *resp);
	if (resp == NULL) {
		errno = ENOMEM;
		goto error;
	}

	/* creates the message */
	msg = dbus_message_new_method_call(destination, path, iface, method);
	if (msg == NULL) {
		errno = ENOMEM;
		goto error2;
	}

	/* fill it */
	if (!dbus_message_append_args
	    (msg, DBUS_TYPE_STRING, &query, DBUS_TYPE_INVALID)) {
		errno = ENOMEM;
		goto error3;
	}

	/* send it */
	if (!dbus_connection_send(sbus->connection, msg, &resp->serial)) {
		/* TODO: which error? */
		goto error3;
	}

	/* release the message that is not more used */
	dbus_message_unref(msg);

	/* fulfill the response structure */
	resp->closure = closure;
	resp->onresp = onresp;

	/* links the response to list of reponse waiters */
	resp->next = sbus->waiters;
	sbus->waiters = resp;
	return 0;

 error3:
	dbus_message_unref(msg);
 error2:
	free(resp);
 error:
	return -1;
}

/*
 * Synchronous call to 'method' of 'sbus' passing the string 'query'.
 * The returned string response is returned.
 *
 * Returns the string response or NULL in case of error.
 */
char *sbus_call_sync(
		struct sbus *sbus,
		const char *destination,
		const char *path,
		const char *iface,
		const char *method,
		const char *query)
{
	struct respsync synchro;
	synchro.value = NULL;
	synchro.replied = sbus_call(sbus, destination, path,
				    iface, method, query,
				    (void*)sync_of_replies, &synchro);
	while (!synchro.replied)
		if (sbus->itf->wait(-1, sbus->itfclo) != 0)
			return NULL;
	return synchro.value;
}


/*
 * Records for 'sbus' the string signal handler 'onsig' with closure 'closure'
 * for the signal of 'member'.
 * The callback handler is called with 2 arguments:
 *   1. char *: the string parameter associated to the signal
 *   2. void *: the closure closure.
 *
 * Returns 0 in case of success or -1 otherwise.
 */
struct sbus_signal *sbus_add_signal(
		struct sbus *sbus,
		const char *sender,
		const char *path,
		const char *iface,
		const char *member,
		void (*onsignal) (const struct sbusmsg *, const char *, void *),
		void *closure)
{
	char *rule;
	struct sbus_signal *signal;

	/* allocation */
	signal = calloc(1, sizeof *signal);
	if (signal == NULL)
		goto error;
	if (sender != NULL) {
		signal->sender = strdup(sender);
		if (!signal->sender)
			goto error2;
	}
	if (path != NULL) {
		signal->path = strdup(path);
		if (!signal->path)
			goto error2;
	}
	if (iface != NULL) {
		signal->iface = strdup(iface);
		if (!signal->iface)
			goto error2;
	}
	if (member != NULL) {
		signal->member = strdup(member);
		if (!signal->member)
			goto error2;
	}

	/* record the signal */
	rule = rule_of_signal(signal);
	if (rule == NULL)
		goto error2;
	dbus_bus_add_match(sbus->connection, rule, NULL);
	free(rule);

	/* record the signal */
	signal->onsignal = onsignal;
	signal->closure = closure;
	signal->next = sbus->signals;
	sbus->signals = signal;

	return signal;

 error2:
	free(signal->sender);
	free(signal->path);
	free(signal->iface);
	free(signal->member);
	free(signal);
 error:
	errno = ENOMEM;
	return NULL;
}

/*
 * Removes the 'signal' handler from 'sbus'
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_remove_signal(struct sbus *sbus, struct sbus_signal *signal)
{
	char *rule;
	struct sbus_signal **it;

	it = &sbus->signals;
	while (*it != NULL) {
		if (*it == signal)
			goto found;
		it = &(*it)->next;
	}
	errno = EINVAL;
	return -1;

found:
	rule = rule_of_signal(signal);
	if (rule != NULL) {
		dbus_bus_remove_match(sbus->connection, rule, NULL);
		free(rule);
	}
	*it = signal->next;
	free(signal->sender);
	free(signal->path);
	free(signal->iface);
	free(signal->member);
	free(signal);
	return 0;
}

/*
 * Start to serve: activate services declared for 'sbus'.
 * This function, in fact, declares 'sbus' as the receiver
 * for calls to the destination derived from the path set at
 * 'sbus' creation.
 * It also allows 'sbus' to emit signals of that origin.
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_add_name(struct sbus *sbus, const char *name)
{
	int status = dbus_bus_request_name(sbus->connection, name,
					DBUS_NAME_FLAG_DO_NOT_QUEUE, NULL);
	switch (status) {
	case DBUS_REQUEST_NAME_REPLY_PRIMARY_OWNER:
	case DBUS_REQUEST_NAME_REPLY_ALREADY_OWNER:
		return 0;
	case DBUS_REQUEST_NAME_REPLY_EXISTS:
	case DBUS_REQUEST_NAME_REPLY_IN_QUEUE:
	default:
		errno = EADDRINUSE;
		return -1;
	}
}

/*
 * Adds to 'sbus' a service handling calls to the 'method' using
 * the callback 'oncall' and the closure value 'closure'.
 *
 * The callback 'oncall' is invoked for handling incoming method
 * calls. It receives 3 parameters:
 *   1. struct sbusmsg *: a handler to data to be used for replying
 *   2. const char *: the received string
 *   3. void *: the closure 'closure' set by this function
 *
 * Returns 0 in case of success or -1 in case of error.
 */
struct sbus_service *sbus_add_service(
		struct sbus *sbus,
		const char *destination,
		const char *path,
		const char *iface,
		const char *member,
		void (*oncall) (struct sbusmsg *, const char *, void *),
		void *closure)
{
	struct sbus_service *service;

	/* allocation */
	service = calloc(1, sizeof *service);
	if (service == NULL)
		goto error;
	if (destination != NULL) {
		service->destination = strdup(destination);
		if (!service->destination)
			goto error2;
	}
	if (path != NULL) {
		service->path = strdup(path);
		if (!service->path)
			goto error2;
	}
	if (iface != NULL) {
		service->iface = strdup(iface);
		if (!service->iface)
			goto error2;
	}
	if (member != NULL) {
		service->member = strdup(member);
		if (!service->member)
			goto error2;
	}

	/* record the service */
	service->oncall = oncall;
	service->closure = closure;
	service->next = sbus->services;
	sbus->services = service;

	return service;

 error2:
	free(service->destination);
	free(service->path);
	free(service->iface);
	free(service->member);
	free(service);
 error:
	errno = ENOMEM;
	return NULL;
}

/*
 * Removes the 'service' handler from 'sbus'
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_remove_service(struct sbus *sbus, struct sbus_service *service)
{
	struct sbus_service **it;

	it = &sbus->services;
	while (*it != NULL) {
		if (*it == service)
			goto found;
		it = &(*it)->next;
	}
	errno = EINVAL;
	return -1;

found:
	*it = service->next;
	free(service->destination);
	free(service->path);
	free(service->iface);
	free(service->member);
	free(service);
	return 0;
}

const char *sbus_sender(const struct sbusmsg *smsg)
{
	return dbus_message_get_sender(smsg->message);
}

const char *sbus_destination(const struct sbusmsg *smsg)
{
	return dbus_message_get_destination(smsg->message);
}

const char *sbus_path(const struct sbusmsg *smsg)
{
	return dbus_message_get_path(smsg->message);
}

const char *sbus_interface(const struct sbusmsg *smsg)
{
	return dbus_message_get_interface(smsg->message);
}

const char *sbus_member(const struct sbusmsg *smsg)
{
	return dbus_message_get_member(smsg->message);
}

/*
 * Replies an error of string 'error' to the request handled by 'smsg'.
 * Also destroys the request 'smsg' that must not be used later.
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_reply_error(struct sbusmsg *smsg, const char *error)
{
	int rc = -1;
	DBusMessage *message;

	message = dbus_message_new_error(smsg->message, DBUS_ERROR_FAILED,
								error);
	if (message == NULL)
		errno = ENOMEM;
	else {
		if (dbus_connection_send(smsg->connection, message, NULL))
			rc = 0;
		dbus_message_unref(message);
	}
	free_sbusmsg(smsg);
	return rc;
}

/*
 * Replies normally the string 'reply' to the request handled by 'smsg'.
 * Also destroys the request 'smsg' that must not be used later.
 *
 * Returns 0 in case of success or -1 in case of error.
 */
int sbus_reply(struct sbusmsg *smsg, const char *reply)
{
	int rc = -1;
	DBusMessage *message;

	message = dbus_message_new_method_return(smsg->message);
	if (message == NULL)
		return reply_out_of_memory(smsg);

	if (!dbus_message_append_args
	    (message, DBUS_TYPE_STRING, &reply, DBUS_TYPE_INVALID)) {
		dbus_message_unref(message);
		return reply_out_of_memory(smsg);
	}

	if (dbus_connection_send(smsg->connection, message, NULL))
		rc = 0;
	dbus_message_unref(message);
	free_sbusmsg(smsg);
	return rc;
}

/****************** FEW LITTLE TESTS *****************************************/

#if defined(SERVER)||defined(CLIENT)
#include <stdio.h>
#include <unistd.h>
#include "utils-upoll.h"

static int mwait(int timeout, void *closure)
{
	upoll_wait(timeout);
	return 0;
}

static const struct sbus_itf uitf = {
	.wait = (void*)mwait,
	.open = (void*)upoll_open,
	.on_readable = (void*)upoll_on_readable,
	.on_writable = (void*)upoll_on_writable,
	.on_hangup = (void*)upoll_on_hangup,
	.close = (void*)upoll_close
};

static const char name[] = "org.toto";
static const char path[] = "/org/toto";
static const char iface[] = "org.toto";
static struct sbus *sbus;

#ifdef SERVER
void ping(struct sbusmsg *smsg, const char *request, void *unused)
{
	printf("ping(%s) -> %s\n", request, request);
	sbus_reply(smsg, request);
}

void incr(struct sbusmsg *smsg, const char *request, void *unused)
{
	static int counter = 0;
	char res[150];
	sprintf(res, "%d", ++counter);
	printf("incr(%s) -> %s\n", request, res);
	sbus_reply(smsg, res);
	sbus_send_signal(sbus, name, path, iface, "incremented", res);
}

int main()
{
	int s1, s2, s3;
	sbus = sbus_session(&uitf, NULL);
	s3 = !sbus_add_name(sbus, name);
	s1 = !!sbus_add_service(sbus, name, path, iface, "ping", ping, NULL);
	s2 = !!sbus_add_service(sbus, name, path, iface, "incr", incr, NULL);
	printf("started %d %d %d\n", s1, s2, s3);
	while (1) upoll_wait(-1);
}
#endif

#ifdef CLIENT
void onresp(int status, const char *response, void *closure)
{
	printf("resp: %d, %s, %s\n", status, (const char *)closure, response);
}

void signaled(const struct sbusmsg *req, const char *data, void *closure)
{
	printf("signaled with {%s}/%s\n", data, (const char*)closure);
}

int main()
{
	int i = 10;
	sbus = sbus_session(&uitf, NULL);
	sbus_add_signal(sbus, name, path, iface, "incremented", signaled, "signal");
	while (i--) {
		sbus_call(sbus, name, path, iface, "ping", "{'toto':[1,2,3,4,true,'toto']}", onresp, "ping");
		sbus_call(sbus, name, path, iface, "incr", "{'doit':'for-me'}", onresp, "incr");
		upoll_wait(1);
	}
	printf("[[[%s]]]\n", sbus_call_sync(sbus, name, path, iface, "ping", "formidable!"));
	while (1) upoll_wait(-1);
}
#endif
#endif