libmapper/mapper.c - openbmc/phosphor-objmgr - Gitiles

 /**
  * Copyright © 2016 IBM Corporation
  *
  * 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.
  */
 #include "config.h"
 #include <stdlib.h>
 #include <string.h>
 #include <stdio.h>
 #include <errno.h>
 #include <unistd.h>
 #include <sys/timerfd.h>
 #include <systemd/sd-bus.h>
 #include <systemd/sd-event.h>
 #include "mapper.h"

 static const char *async_wait_introspection_match =
 	"type='signal',"
 	"sender='xyz.openbmc_project.ObjectMapper',"
 	"interface='xyz.openbmc_project.ObjectMapper.Private',"
 	"member='IntrospectionComplete'";

 static const char *async_wait_interfaces_added_match =
 	"type='signal',"
 	"interface='org.freedesktop.DBus.ObjectManager',"
 	"member='InterfacesAdded'";

 static const char *async_wait_interfaces_removed_match =
 	"type='signal',"
 	"interface='org.freedesktop.DBus.ObjectManager',"
 	"member='InterfacesRemoved'";

 static const int mapper_busy_retries = 5;
 static const uint64_t mapper_busy_delay_interval_usec = 1000000;

 struct mapper_async_wait
 {
 	char *intf;
 	char **objs;
 	void (*callback)(int, void *);
 	void *userdata;
 	sd_event *loop;
 	sd_bus *conn;
 	sd_bus_slot *introspection_slot;
 	sd_bus_slot *intf_slot;
 	int *status;
 	int count;
 	int finished;
 	int r;
 	bool added;
 };

 struct async_wait_callback_data
 {
 	mapper_async_wait *wait;
 	const char *path;
 	sd_event_source *event_source;
 	int retry;
 };

 static int async_wait_match_introspection_complete(sd_bus_message *, void *,
 		sd_bus_error *);
 static int async_wait_check_done(mapper_async_wait *);
 static void async_wait_done(int r, mapper_async_wait *);
 static int async_wait_get_objects(mapper_async_wait *);
 static int async_wait_getobject_callback(sd_bus_message *,
 		void *, sd_bus_error *);

 static int sarraylen(char *array[])
 {
 	int count = 0;
 	char **p = array;

 	while(*p != NULL) {
 		++count;
 		++p;
 	}

 	return count;
 }

 static void sarrayfree(char *array[])
 {
 	char **p = array;
 	while(*p != NULL) {
 		free(*p);
 		++p;
 	}
 	free(array);
 }

 static char **sarraydup(char *array[])
 {
 	int count = sarraylen(array);
 	int i;
 	char **ret = NULL;

 	ret = malloc(sizeof(*ret) * count);
 	if(!ret)
 		return NULL;

 	for(i=0; i<count; ++i) {
 		ret[i] = strdup(array[i]);
 		if(!ret[i])
 			goto error;
 	}

 	return ret;

 error:
 	sarrayfree(ret);
 	return NULL;
 }

 static int async_wait_timeout_callback(sd_event_source *s,
 		uint64_t usec, void *userdata)
 {
 	int r;
 	struct async_wait_callback_data *data = userdata;
 	mapper_async_wait *wait = data->wait;

 	sd_event_source_unref(data->event_source);
 	r = sd_bus_call_method_async(
 			wait->conn,
 			NULL,
 			MAPPER_BUSNAME,
 			MAPPER_PATH,
 			MAPPER_INTERFACE,
 			"GetObject",
 			async_wait_getobject_callback,
 			data,
 			"sas",
 			data->path,
 			0,
 			NULL);
 	if(r < 0) {
 		async_wait_done(r, wait);
 		free(data);
 	}

 	return 0;
 }

 static int get_interface(sd_bus_message *m,
 		mapper_async_wait *wait, char* interface)
 {
 	int r = 0;
 	char* tmp_intf = NULL;

 	for(int i = 0; i<wait->count; ++i) {
 		sd_bus_error error = SD_BUS_ERROR_NULL;
 		r = sd_bus_call_method(
 				wait->conn,
 				MAPPER_BUSNAME,
 				MAPPER_PATH,
 				MAPPER_INTERFACE,
 				"GetSubTreePaths",
 				&error,
 				&m,
 				"sias",
 				wait->objs[i],
 				0, 1,
 				wait->intf);
 		if (r < 0) {
 			fprintf(stderr, "Error invoking method: %s\n",
 					strerror(-r));
 			return r;
 		}

 		r = sd_bus_message_read(m, "as", 1, &tmp_intf);
 		if (r < 0) {
 			// Ignore the errno when the intf does not exist (ENXIO)
 			if (r == -ENXIO) {
 				r = 0;
 				continue;
 			}
 		} else
 			break;
 	}

 	if (tmp_intf)
 		strcpy(interface, tmp_intf);

 	return r;
 }

 static int async_wait_getobject_callback(sd_bus_message *m,
 		void *userdata,
 		sd_bus_error *e)
 {
 	int i, r;
 	struct async_wait_callback_data *data = userdata;
 	mapper_async_wait *wait = data->wait;
 	uint64_t now;

 	if(wait->finished)
 		goto exit;

 	r = sd_bus_message_get_errno(m);

 	if (!r && !wait->added) {
 		// Dbus object exists, need to check if it has the requested interface
 		char intf[256];
 		intf[0] = '\0';
 		r = get_interface(m, wait, intf);
 		if ((r < 0) || (strlen(intf) != 0))
 			goto exit;
 		else
 			r = 0;
 	}

 	if(r == ENOENT) {
 		if (wait->added)
 			goto exit;
 		else
 			r = 0;
 	}

 	if(r == EBUSY && data->retry < mapper_busy_retries) {
 		r = sd_event_now(wait->loop,
 				CLOCK_MONOTONIC,
 				&now);
 		if(r < 0) {
 			async_wait_done(r, wait);
 			goto exit;
 		}

 		++data->retry;
 		r = sd_event_add_time(wait->loop,
 				&data->event_source,
 				CLOCK_MONOTONIC,
 				now + mapper_busy_delay_interval_usec,
 				0,
 				async_wait_timeout_callback,
 				data);
 		if(r < 0) {
 			async_wait_done(r, wait);
 			goto exit;
 		}

 		return 0;
 	}

 	if(r) {
 		async_wait_done(-r, wait);
 		goto exit;
 	}

 	for(i=0; i<wait->count; ++i) {
 		if(!strcmp(data->path, wait->objs[i])) {
 			wait->status[i] = 1;
 		}
 	}

 	if(async_wait_check_done(wait))
 		async_wait_done(0, wait);

 exit:
 	free(data);
 	return 0;
 }

 static int async_wait_get_objects(mapper_async_wait *wait)
 {
 	int i, r;
 	struct async_wait_callback_data *data = NULL;

 	for(i=0; i<wait->count; ++i) {
 		if(wait->status[i])
 			continue;
 		data = malloc(sizeof(*data));
 		data->wait = wait;
 		data->path = wait->objs[i];
 		data->retry = 0;
 		data->event_source = NULL;
 		r = sd_bus_call_method_async(
 				wait->conn,
 				NULL,
 				MAPPER_BUSNAME,
 				MAPPER_PATH,
 				MAPPER_INTERFACE,
 				"GetObject",
 				async_wait_getobject_callback,
 				data,
 				"sas",
 				wait->objs[i],
 				0,
 				NULL);
 		if(r < 0) {
 			free(data);
 			fprintf(stderr, "Error invoking method: %s\n",
 					strerror(-r));
 			return r;
 		}
 	}

 	return 0;
 }

 static int async_wait_match_introspection_complete(sd_bus_message *m, void *w,
 		sd_bus_error *e)
 {
 	int r;

 	mapper_async_wait *wait = w;
 	if(wait->finished)
 		return 0;

 	r = async_wait_get_objects(wait);
 	if(r < 0)
 		async_wait_done(r, wait);

 	return 0;
 }

 static void async_wait_done(int r, mapper_async_wait *w)
 {
 	if(w->finished)
 		return;

 	w->finished = 1;
 	sd_bus_slot_unref(w->introspection_slot);
 	sd_bus_slot_unref(w->intf_slot);

 	if(w->callback)
 		w->callback(r, w->userdata);
 }

 static int async_wait_check_done(mapper_async_wait *w)
 {
 	int i;

 	if(w->finished)
 		return 1;

 	for(i=0; i<w->count; ++i)
 		if(!w->status[i])
 			return 0;

 	return 1;
 }

 void mapper_wait_async_free(mapper_async_wait *w)
 {
 	free(w->status);
 	sarrayfree(w->objs);
 	free(w);
 }

 int mapper_wait_async(sd_bus *conn,
 		sd_event *loop,
 		const char *intf,
 		char *objs[],
 		void (*callback)(int, void *),
 		void *userdata,
 		mapper_async_wait **w,
 		bool added)
 {
 	int r;
 	mapper_async_wait *wait = NULL;

 	wait = malloc(sizeof(*wait));
 	if(!wait)
 		return -ENOMEM;

 	memset(wait, 0, sizeof(*wait));
 	wait->conn = conn;
 	wait->loop = loop;
 	wait->callback = callback;
 	wait->userdata = userdata;
 	wait->count = sarraylen(objs);
 	if(!wait->count)
 		return 0;
 	wait->added = added;
 	if (intf != NULL)
 		wait->intf = strdup(intf);
 	else
 		wait->intf = NULL;

 	wait->objs = sarraydup(objs);
 	if(!wait->objs) {
 		r = -ENOMEM;
 		goto free_wait;
 	}

 	wait->status = malloc(sizeof(*wait->status) * wait->count);
 	if(!wait->status) {
 		r = -ENOMEM;
 		goto free_objs;
 	}
 	memset(wait->status, 0, sizeof(*wait->status) * wait->count);

 	if (wait->added) {
 		r = sd_bus_add_match(conn,
 				&wait->introspection_slot,
 				async_wait_introspection_match,
 				async_wait_match_introspection_complete,
 				wait);
 		if(r < 0) {
 			fprintf(stderr, "Error adding match rule: %s\n",
 					strerror(-r));
 			goto free_status;
 		}

 		r = sd_bus_add_match(conn,
 				&wait->intf_slot,
 				async_wait_interfaces_added_match,
 				async_wait_match_introspection_complete,
 				wait);
 		if(r < 0) {
 			fprintf(stderr, "Error adding match rule: %s\n",
 					strerror(-r));
 			goto unref_name_slot;
 		}
 	} else {
 		r = sd_bus_add_match(conn,
 				&wait->intf_slot,
 				async_wait_interfaces_removed_match,
 				async_wait_match_introspection_complete,
 				wait);
 		if(r < 0) {
 			fprintf(stderr, "Error adding match rule: %s\n",
 					strerror(-r));
 			goto unref_name_slot;
 		}
 	}

 	r = async_wait_get_objects(wait);
 	if(r < 0) {
 		fprintf(stderr, "Error calling method: %s\n",
 				strerror(-r));
 		goto unref_intf_slot;
 	}

 	*w = wait;

 	return 0;

 unref_intf_slot:
 	sd_bus_slot_unref(wait->intf_slot);
 unref_name_slot:
 	sd_bus_slot_unref(wait->introspection_slot);
 free_status:
 	free(wait->status);
 free_objs:
 	sarrayfree(wait->objs);
 free_wait:
 	free(wait);

 	return r;
 }

 int mapper_get_object(sd_bus *conn, const char *obj, sd_bus_message **reply)
 {
 	sd_bus_error error = SD_BUS_ERROR_NULL;
 	sd_bus_message *request = NULL;
 	int r, retry = 0;

 	r = sd_bus_message_new_method_call(
 			conn,
 			&request,
 			MAPPER_BUSNAME,
 			MAPPER_PATH,
 			MAPPER_INTERFACE,
 			"GetObject");
 	if (r < 0)
 		goto exit;

 	r = sd_bus_message_append(request, "s", obj);
 	if (r < 0)
 		goto exit;
 	r = sd_bus_message_append(request, "as", 0, NULL);
 	if (r < 0)
 		goto exit;

 	while(retry < mapper_busy_retries) {
 		sd_bus_error_free(&error);
 		r = sd_bus_call(conn, request, 0, &error, reply);
 		if (r < 0 && sd_bus_error_get_errno(&error) == EBUSY) {
 			++retry;

 			if(retry != mapper_busy_retries)
 				usleep(mapper_busy_delay_interval_usec);
 			continue;
 		}
 		break;
 	}

 	if (r < 0)
 		goto exit;

 exit:
 	sd_bus_error_free(&error);
 	sd_bus_message_unref(request);

 	return r;
 }

 int mapper_get_service(sd_bus *conn, const char *obj, char **service)
 {
 	sd_bus_message *reply = NULL;
 	const char *tmp;
 	int r;

 	r = mapper_get_object(conn, obj, &reply);
 	if (r < 0)
 		goto exit;

 	r = sd_bus_message_enter_container(reply, 0, NULL);
 	if (r < 0)
 		goto exit;

 	r = sd_bus_message_enter_container(reply, 0, NULL);
 	if (r < 0)
 		goto exit;

 	r = sd_bus_message_read(reply, "s", &tmp);
 	if (r < 0)
 		goto exit;

 	*service = strdup(tmp);

 exit:
 	sd_bus_message_unref(reply);

 	return r;
 }
	/**
	* Copyright © 2016 IBM Corporation
	*
	* 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.
	*/
	#include "config.h"
	#include <stdlib.h>
	#include <string.h>
	#include <stdio.h>
	#include <errno.h>
	#include <unistd.h>
	#include <sys/timerfd.h>
	#include <systemd/sd-bus.h>
	#include <systemd/sd-event.h>
	#include "mapper.h"

	static const char *async_wait_introspection_match =
	"type='signal',"
	"sender='xyz.openbmc_project.ObjectMapper',"
	"interface='xyz.openbmc_project.ObjectMapper.Private',"
	"member='IntrospectionComplete'";

	static const char *async_wait_interfaces_added_match =
	"type='signal',"
	"interface='org.freedesktop.DBus.ObjectManager',"
	"member='InterfacesAdded'";

	static const char *async_wait_interfaces_removed_match =
	"type='signal',"
	"interface='org.freedesktop.DBus.ObjectManager',"
	"member='InterfacesRemoved'";

	static const int mapper_busy_retries = 5;
	static const uint64_t mapper_busy_delay_interval_usec = 1000000;

	struct mapper_async_wait
	{
	char *intf;
	char **objs;
	void (callback)(int, void );
	void *userdata;
	sd_event *loop;
	sd_bus *conn;
	sd_bus_slot *introspection_slot;
	sd_bus_slot *intf_slot;
	int *status;
	int count;
	int finished;
	int r;
	bool added;
	};

	struct async_wait_callback_data
	{
	mapper_async_wait *wait;
	const char *path;
	sd_event_source *event_source;
	int retry;
	};

	static int async_wait_match_introspection_complete(sd_bus_message , void ,
	sd_bus_error *);
	static int async_wait_check_done(mapper_async_wait *);
	static void async_wait_done(int r, mapper_async_wait *);
	static int async_wait_get_objects(mapper_async_wait *);
	static int async_wait_getobject_callback(sd_bus_message *,
	void , sd_bus_error );

	static int sarraylen(char *array[])
	{
	int count = 0;
	char **p = array;

	while(*p != NULL) {
	++count;
	++p;
	}

	return count;
	}

	static void sarrayfree(char *array[])
	{
	char **p = array;
	while(*p != NULL) {
	free(*p);
	++p;
	}
	free(array);
	}

	static char *sarraydup(char array[])
	{
	int count = sarraylen(array);
	int i;
	char **ret = NULL;

	ret = malloc(sizeof(ret) count);
	if(!ret)
	return NULL;

	for(i=0; i<count; ++i) {
	ret[i] = strdup(array[i]);
	if(!ret[i])
	goto error;
	}

	return ret;

	error:
	sarrayfree(ret);
	return NULL;
	}

	static int async_wait_timeout_callback(sd_event_source *s,
	uint64_t usec, void *userdata)
	{
	int r;
	struct async_wait_callback_data *data = userdata;
	mapper_async_wait *wait = data->wait;

	sd_event_source_unref(data->event_source);
	r = sd_bus_call_method_async(
	wait->conn,
	NULL,
	MAPPER_BUSNAME,
	MAPPER_PATH,
	MAPPER_INTERFACE,
	"GetObject",
	async_wait_getobject_callback,
	data,
	"sas",
	data->path,
	0,
	NULL);
	if(r < 0) {
	async_wait_done(r, wait);
	free(data);
	}

	return 0;
	}

	static int get_interface(sd_bus_message *m,
	mapper_async_wait wait, char interface)
	{
	int r = 0;
	char* tmp_intf = NULL;

	for(int i = 0; i<wait->count; ++i) {
	sd_bus_error error = SD_BUS_ERROR_NULL;
	r = sd_bus_call_method(
	wait->conn,
	MAPPER_BUSNAME,
	MAPPER_PATH,
	MAPPER_INTERFACE,
	"GetSubTreePaths",
	&error,
	&m,
	"sias",
	wait->objs[i],
	0, 1,
	wait->intf);
	if (r < 0) {
	fprintf(stderr, "Error invoking method: %s\n",
	strerror(-r));
	return r;
	}

	r = sd_bus_message_read(m, "as", 1, &tmp_intf);
	if (r < 0) {
	// Ignore the errno when the intf does not exist (ENXIO)
	if (r == -ENXIO) {
	r = 0;
	continue;
	}
	} else
	break;
	}

	if (tmp_intf)
	strcpy(interface, tmp_intf);

	return r;
	}

	static int async_wait_getobject_callback(sd_bus_message *m,
	void *userdata,
	sd_bus_error *e)
	{
	int i, r;
	struct async_wait_callback_data *data = userdata;
	mapper_async_wait *wait = data->wait;
	uint64_t now;

	if(wait->finished)
	goto exit;

	r = sd_bus_message_get_errno(m);

	if (!r && !wait->added) {
	// Dbus object exists, need to check if it has the requested interface
	char intf[256];
	intf[0] = '\0';
	r = get_interface(m, wait, intf);
	if ((r < 0) \|\| (strlen(intf) != 0))
	goto exit;
	else
	r = 0;
	}

	if(r == ENOENT) {
	if (wait->added)
	goto exit;
	else
	r = 0;
	}

	if(r == EBUSY && data->retry < mapper_busy_retries) {
	r = sd_event_now(wait->loop,
	CLOCK_MONOTONIC,
	&now);
	if(r < 0) {
	async_wait_done(r, wait);
	goto exit;
	}

	++data->retry;
	r = sd_event_add_time(wait->loop,
	&data->event_source,
	CLOCK_MONOTONIC,
	now + mapper_busy_delay_interval_usec,
	0,
	async_wait_timeout_callback,
	data);
	if(r < 0) {
	async_wait_done(r, wait);
	goto exit;
	}

	return 0;
	}

	if(r) {
	async_wait_done(-r, wait);
	goto exit;
	}

	for(i=0; i<wait->count; ++i) {
	if(!strcmp(data->path, wait->objs[i])) {
	wait->status[i] = 1;
	}
	}

	if(async_wait_check_done(wait))
	async_wait_done(0, wait);

	exit:
	free(data);
	return 0;
	}

	static int async_wait_get_objects(mapper_async_wait *wait)
	{
	int i, r;
	struct async_wait_callback_data *data = NULL;

	for(i=0; i<wait->count; ++i) {
	if(wait->status[i])
	continue;
	data = malloc(sizeof(*data));
	data->wait = wait;
	data->path = wait->objs[i];
	data->retry = 0;
	data->event_source = NULL;
	r = sd_bus_call_method_async(
	wait->conn,
	NULL,
	MAPPER_BUSNAME,
	MAPPER_PATH,
	MAPPER_INTERFACE,
	"GetObject",
	async_wait_getobject_callback,
	data,
	"sas",
	wait->objs[i],
	0,
	NULL);
	if(r < 0) {
	free(data);
	fprintf(stderr, "Error invoking method: %s\n",
	strerror(-r));
	return r;
	}
	}

	return 0;
	}

	static int async_wait_match_introspection_complete(sd_bus_message m, void w,
	sd_bus_error *e)
	{
	int r;

	mapper_async_wait *wait = w;
	if(wait->finished)
	return 0;

	r = async_wait_get_objects(wait);
	if(r < 0)
	async_wait_done(r, wait);

	return 0;
	}

	static void async_wait_done(int r, mapper_async_wait *w)
	{
	if(w->finished)
	return;

	w->finished = 1;
	sd_bus_slot_unref(w->introspection_slot);
	sd_bus_slot_unref(w->intf_slot);

	if(w->callback)
	w->callback(r, w->userdata);
	}

	static int async_wait_check_done(mapper_async_wait *w)
	{
	int i;

	if(w->finished)
	return 1;

	for(i=0; i<w->count; ++i)
	if(!w->status[i])
	return 0;

	return 1;
	}

	void mapper_wait_async_free(mapper_async_wait *w)
	{
	free(w->status);
	sarrayfree(w->objs);
	free(w);
	}

	int mapper_wait_async(sd_bus *conn,
	sd_event *loop,
	const char *intf,
	char *objs[],
	void (callback)(int, void ),
	void *userdata,
	mapper_async_wait **w,
	bool added)
	{
	int r;
	mapper_async_wait *wait = NULL;

	wait = malloc(sizeof(*wait));
	if(!wait)
	return -ENOMEM;

	memset(wait, 0, sizeof(*wait));
	wait->conn = conn;
	wait->loop = loop;
	wait->callback = callback;
	wait->userdata = userdata;
	wait->count = sarraylen(objs);
	if(!wait->count)
	return 0;
	wait->added = added;
	if (intf != NULL)
	wait->intf = strdup(intf);
	else
	wait->intf = NULL;

	wait->objs = sarraydup(objs);
	if(!wait->objs) {
	r = -ENOMEM;
	goto free_wait;
	}

	wait->status = malloc(sizeof(wait->status) wait->count);
	if(!wait->status) {
	r = -ENOMEM;
	goto free_objs;
	}
	memset(wait->status, 0, sizeof(wait->status) wait->count);

	if (wait->added) {
	r = sd_bus_add_match(conn,
	&wait->introspection_slot,
	async_wait_introspection_match,
	async_wait_match_introspection_complete,
	wait);
	if(r < 0) {
	fprintf(stderr, "Error adding match rule: %s\n",
	strerror(-r));
	goto free_status;
	}

	r = sd_bus_add_match(conn,
	&wait->intf_slot,
	async_wait_interfaces_added_match,
	async_wait_match_introspection_complete,
	wait);
	if(r < 0) {
	fprintf(stderr, "Error adding match rule: %s\n",
	strerror(-r));
	goto unref_name_slot;
	}
	} else {
	r = sd_bus_add_match(conn,
	&wait->intf_slot,
	async_wait_interfaces_removed_match,
	async_wait_match_introspection_complete,
	wait);
	if(r < 0) {
	fprintf(stderr, "Error adding match rule: %s\n",
	strerror(-r));
	goto unref_name_slot;
	}
	}

	r = async_wait_get_objects(wait);
	if(r < 0) {
	fprintf(stderr, "Error calling method: %s\n",
	strerror(-r));
	goto unref_intf_slot;
	}

	*w = wait;

	return 0;

	unref_intf_slot:
	sd_bus_slot_unref(wait->intf_slot);
	unref_name_slot:
	sd_bus_slot_unref(wait->introspection_slot);
	free_status:
	free(wait->status);
	free_objs:
	sarrayfree(wait->objs);
	free_wait:
	free(wait);

	return r;
	}

	int mapper_get_object(sd_bus conn, const char obj, sd_bus_message **reply)
	{
	sd_bus_error error = SD_BUS_ERROR_NULL;
	sd_bus_message *request = NULL;
	int r, retry = 0;

	r = sd_bus_message_new_method_call(
	conn,
	&request,
	MAPPER_BUSNAME,
	MAPPER_PATH,
	MAPPER_INTERFACE,
	"GetObject");
	if (r < 0)
	goto exit;

	r = sd_bus_message_append(request, "s", obj);
	if (r < 0)
	goto exit;
	r = sd_bus_message_append(request, "as", 0, NULL);
	if (r < 0)
	goto exit;

	while(retry < mapper_busy_retries) {
	sd_bus_error_free(&error);
	r = sd_bus_call(conn, request, 0, &error, reply);
	if (r < 0 && sd_bus_error_get_errno(&error) == EBUSY) {
	++retry;

	if(retry != mapper_busy_retries)
	usleep(mapper_busy_delay_interval_usec);
	continue;
	}
	break;
	}

	if (r < 0)
	goto exit;

	exit:
	sd_bus_error_free(&error);
	sd_bus_message_unref(request);

	return r;
	}

	int mapper_get_service(sd_bus conn, const char obj, char **service)
	{
	sd_bus_message *reply = NULL;
	const char *tmp;
	int r;

	r = mapper_get_object(conn, obj, &reply);
	if (r < 0)
	goto exit;

	r = sd_bus_message_enter_container(reply, 0, NULL);
	if (r < 0)
	goto exit;

	r = sd_bus_message_enter_container(reply, 0, NULL);
	if (r < 0)
	goto exit;

	r = sd_bus_message_read(reply, "s", &tmp);
	if (r < 0)
	goto exit;

	*service = strdup(tmp);

	exit:
	sd_bus_message_unref(reply);

	return r;
	}