]> git.meshlink.io Git - catta/blobdiff - avahi-client/client.c
* avahi-utils: replace python avahi-browse with a version written in C.
[catta] / avahi-client / client.c
index 36434036aeca2e062b3b44a1cb4d631ffca7bd5d..ce4cfa0df4eb03d38e46b687198cd89e484fba82 100644 (file)
-#include <avahi-client/client.h>
-#include <avahi-common/dbus.h>
-#include <glib.h>
+/* $Id$ */
 
-#define DBUS_API_SUBJECT_TO_CHANGE
-#include <dbus/dbus.h>
+/***
+  This file is part of avahi.
+  avahi is free software; you can redistribute it and/or modify it
+  under the terms of the GNU Lesser General Public License as
+  published by the Free Software Foundation; either version 2.1 of the
+  License, or (at your option) any later version.
+  avahi 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 Lesser General
+  Public License for more details.
+  You should have received a copy of the GNU Lesser General Public
+  License along with avahi; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
+  USA.
+***/
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif
 
 #include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+
+#include <dbus/dbus.h>
+
+#include <avahi-common/dbus.h>
+#include <avahi-common/llist.h>
+#include <avahi-common/error.h>
+#include <avahi-common/dbus.h>
+#include <avahi-common/malloc.h>
+#include <avahi-common/dbus-watch-glue.h>
+
+#include "client.h"
+#include "internal.h"
+
+int avahi_client_set_errno (AvahiClient *client, int error) {
+    assert(client);
+
+    return client->error = error;
+}
+
+int avahi_client_set_dbus_error(AvahiClient *client, DBusError *error) {
+    assert(client);
+    assert(error);
+
+    return avahi_client_set_errno(client, avahi_error_dbus_to_number(error->name));
+}
+
+static void client_set_state (AvahiClient *client, AvahiServerState state) {
+    assert(client);
+
+    if (client->state == state)
+        return;
+
+    client->state = state;
+
+    switch (client->state) {
+        case AVAHI_CLIENT_DISCONNECTED:
+            if (client->bus) {
+                dbus_connection_disconnect(client->bus);
+                dbus_connection_unref(client->bus);
+                client->bus = NULL;
+            }
+            
+            /* Fall through */
+            
+        case AVAHI_CLIENT_S_COLLISION:
+        case AVAHI_CLIENT_S_REGISTERING:
+
+            /* Clear cached strings */
+            avahi_free(client->host_name);
+            avahi_free(client->host_name_fqdn);
+            avahi_free(client->domain_name);
+
+            client->host_name =  NULL;
+            client->host_name_fqdn = NULL;
+            client->domain_name = NULL;
+            break;
+
+        case AVAHI_CLIENT_S_RUNNING:
+            break;
+            
+    }
+    
+    if (client->callback)
+        client->callback (client, state, client->userdata);
+}
+
+static DBusHandlerResult filter_func(DBusConnection *bus, DBusMessage *message, void *userdata) {
+    AvahiClient *client = userdata;
+    DBusError error;
+
+    assert(bus);
+    assert(message);
+    
+    dbus_error_init (&error);
+
+/*     fprintf(stderr, "dbus: interface=%s, path=%s, member=%s\n", */
+/*             dbus_message_get_interface (message), */
+/*             dbus_message_get_path (message), */
+/*             dbus_message_get_member (message)); */
+
+    if (client->state == AVAHI_CLIENT_DISCONNECTED)
+        goto fail;
+
+    if (dbus_message_is_signal(message, DBUS_INTERFACE_LOCAL, "Disconnected")) {
+
+        /* The DBUS server died or kicked us */
+        client_set_state(client, AVAHI_CLIENT_DISCONNECTED);
+
+    } if (dbus_message_is_signal(message, DBUS_INTERFACE_DBUS, "NameOwnerChanged")) {
+        char *name, *old, *new;
+        
+        if (!dbus_message_get_args(
+                  message, &error,
+                  DBUS_TYPE_STRING, &name,
+                  DBUS_TYPE_STRING, &old,
+                  DBUS_TYPE_STRING, &new,
+                  DBUS_TYPE_INVALID) || dbus_error_is_set (&error)) {
+
+            fprintf(stderr, "WARNING: Failed to parse NameOwnerChanged signal: %s\n", error.message);
+            goto fail;
+        }
+
+        if (strcmp(name, AVAHI_DBUS_NAME) == 0)
+
+            /* Regardless if the server lost or acquired its name or
+             * if the name was transfered: our services are no longer
+             * available, so we disconnect ourselves */
+            
+            client_set_state(client, AVAHI_CLIENT_DISCONNECTED);
+
+    } else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_SERVER, "StateChanged")) {
+        int32_t state;
+        char *e = NULL;
+        int c;
+        
+        if (!dbus_message_get_args(
+                  message, &error,
+                  DBUS_TYPE_INT32, &state,
+                  DBUS_TYPE_STRING, &e,
+                  DBUS_TYPE_INVALID) || dbus_error_is_set (&error)) {
+            fprintf(stderr, "WARNING: Failed to parse Server.StateChanged signal: %s\n", error.message);
+            goto fail;
+        }
+
+        if ((c = avahi_error_dbus_to_number(e)) != AVAHI_OK)
+            avahi_client_set_errno(client, c);
+        
+        client_set_state(client, (AvahiClientState) state);
+
+    } else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_ENTRY_GROUP, "StateChanged")) {
+        const char *path;
+        AvahiEntryGroup *g;
+        path = dbus_message_get_path(message);
+
+        for (g = client->groups; g; g = g->groups_next)
+            if (strcmp(g->path, path) == 0)
+                break;
+        
+        if (g) {
+            int32_t state;
+            char *e;
+            int c;
+            
+            if (!dbus_message_get_args(
+                      message, &error,
+                      DBUS_TYPE_INT32, &state,
+                      DBUS_TYPE_STRING, &e,
+                      DBUS_TYPE_INVALID) ||
+                dbus_error_is_set(&error)) {
+                fprintf(stderr, "WARNING: Failed to parse EntryGroup.StateChanged signal: %s\n", error.message);
+                goto fail;
+            }
+
+            if ((c = avahi_error_dbus_to_number(e)) != AVAHI_OK)
+                avahi_client_set_errno(client, c);
+            
+            avahi_entry_group_set_state(g, state);
+        }
+        
+    } else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_DOMAIN_BROWSER, "ItemNew"))
+        return avahi_domain_browser_event(client, AVAHI_BROWSER_NEW, message);
+    else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_DOMAIN_BROWSER, "ItemRemove")) 
+        return avahi_domain_browser_event(client, AVAHI_BROWSER_REMOVE, message);
+    else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_DOMAIN_BROWSER, "CacheExhausted")) 
+        return avahi_domain_browser_event(client, AVAHI_BROWSER_CACHE_EXHAUSTED, message);
+    else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_DOMAIN_BROWSER, "AllForNow")) 
+        return avahi_domain_browser_event(client, AVAHI_BROWSER_ALL_FOR_NOW, message);
+    else if (dbus_message_is_signal (message, AVAHI_DBUS_INTERFACE_DOMAIN_BROWSER, "Failure")) 
+        return avahi_domain_browser_event(client, AVAHI_BROWSER_FAILURE, message);
+
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_TYPE_BROWSER, "ItemNew")) 
+        return avahi_service_type_browser_event (client, AVAHI_BROWSER_NEW, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_TYPE_BROWSER, "ItemRemove")) 
+        return avahi_service_type_browser_event (client, AVAHI_BROWSER_REMOVE, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_TYPE_BROWSER, "CacheExhausted")) 
+        return avahi_service_type_browser_event (client, AVAHI_BROWSER_CACHE_EXHAUSTED, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_TYPE_BROWSER, "AllForNow")) 
+        return avahi_service_type_browser_event (client, AVAHI_BROWSER_ALL_FOR_NOW, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_TYPE_BROWSER, "Failure")) 
+        return avahi_service_type_browser_event (client, AVAHI_BROWSER_FAILURE, message);
+
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_BROWSER, "ItemNew")) 
+        return avahi_service_browser_event (client, AVAHI_BROWSER_NEW, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_BROWSER, "ItemRemove")) 
+        return avahi_service_browser_event (client, AVAHI_BROWSER_REMOVE, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_BROWSER, "CacheExhausted")) 
+        return avahi_service_browser_event (client, AVAHI_BROWSER_CACHE_EXHAUSTED, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_BROWSER, "AllForNow")) 
+        return avahi_service_browser_event (client, AVAHI_BROWSER_ALL_FOR_NOW, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_BROWSER, "Failure")) 
+        return avahi_service_browser_event (client, AVAHI_BROWSER_FAILURE, message);
+
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_RESOLVER, "Found")) 
+        return avahi_service_resolver_event (client, AVAHI_RESOLVER_FOUND, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_SERVICE_RESOLVER, "Failure")) 
+        return avahi_service_resolver_event (client, AVAHI_RESOLVER_FAILURE, message);
 
-AvahiClient *
-avahi_client_new ()
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_HOST_NAME_RESOLVER, "Found")) 
+        return avahi_host_name_resolver_event (client, AVAHI_RESOLVER_FOUND, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_HOST_NAME_RESOLVER, "Failure")) 
+        return avahi_host_name_resolver_event (client, AVAHI_RESOLVER_FAILURE, message);
+
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_ADDRESS_RESOLVER, "Found")) 
+        return avahi_address_resolver_event (client, AVAHI_RESOLVER_FOUND, message);
+    else if (dbus_message_is_signal(message, AVAHI_DBUS_INTERFACE_ADDRESS_RESOLVER, "Failure")) 
+        return avahi_address_resolver_event (client, AVAHI_RESOLVER_FAILURE, message);
+    
+    return DBUS_HANDLER_RESULT_HANDLED;
+
+fail:
+
+    dbus_error_free (&error);
+    return DBUS_HANDLER_RESULT_NOT_YET_HANDLED;
+}
+
+static int get_server_state(AvahiClient *client, int *ret_error) {
+    DBusMessage *message = NULL, *reply = NULL;
+    DBusError error;
+    int32_t state;
+    int e = AVAHI_ERR_NO_MEMORY;
+    
+    assert(client);
+
+    dbus_error_init(&error);
+
+    if (!(message = dbus_message_new_method_call(AVAHI_DBUS_NAME, AVAHI_DBUS_PATH_SERVER, AVAHI_DBUS_INTERFACE_SERVER, "GetState")))
+        goto fail;
+
+    reply = dbus_connection_send_with_reply_and_block (client->bus, message, -1, &error);
+
+    if (!reply || dbus_error_is_set (&error))
+        goto fail;
+
+    if (!dbus_message_get_args(reply, &error, DBUS_TYPE_INT32, &state, DBUS_TYPE_INVALID) ||
+        dbus_error_is_set (&error))
+        goto fail;
+
+    client_set_state(client, (AvahiServerState) state);
+
+    dbus_message_unref(message);
+    dbus_message_unref(reply);
+    
+    return AVAHI_OK;
+
+fail:
+    if (dbus_error_is_set(&error)) {
+        e = avahi_error_dbus_to_number (error.name);
+        dbus_error_free(&error);
+    } 
+    
+    if (ret_error)
+        *ret_error = e;
+
+    if (message)
+        dbus_message_unref(message);
+    if (reply)
+        dbus_message_unref(reply);
+    
+    return e;
+}
+
+static int check_version(AvahiClient *client, int *ret_error) {
+    DBusMessage *message = NULL, *reply  = NULL;
+    DBusError error;
+    char *version;
+    int e = AVAHI_ERR_NO_MEMORY;
+    
+    assert(client);
+
+    dbus_error_init(&error);
+
+    if (!(message = dbus_message_new_method_call(AVAHI_DBUS_NAME, AVAHI_DBUS_PATH_SERVER, AVAHI_DBUS_INTERFACE_SERVER, "GetVersionString")))
+        goto fail;
+
+    reply = dbus_connection_send_with_reply_and_block (client->bus, message, -1, &error);
+
+    if (!reply || dbus_error_is_set (&error))
+        goto fail;
+
+    if (!dbus_message_get_args (reply, &error, DBUS_TYPE_STRING, &version, DBUS_TYPE_INVALID) ||
+        dbus_error_is_set (&error))
+        goto fail;
+
+    if (strcmp(version, PACKAGE_STRING) != 0) {
+        e = AVAHI_ERR_VERSION_MISMATCH;
+        goto fail;
+    }
+
+    dbus_message_unref(message);
+    dbus_message_unref(reply);
+               
+    return AVAHI_OK;
+
+fail:
+    if (dbus_error_is_set(&error)) {
+        e = avahi_error_dbus_to_number (error.name);
+        dbus_error_free(&error);
+    } 
+
+    if (ret_error)
+        *ret_error = e;
+
+    if (message)
+        dbus_message_unref(message);
+    if (reply)
+        dbus_message_unref(reply);
+    
+    return e;
+}
+
+
+/* This function acts like dbus_bus_get but creates a private
+ * connection instead */
+static DBusConnection*
+avahi_dbus_bus_get (DBusError *error)
 {
-    AvahiClient *tmp;
+    DBusConnection *conn;
+    const char *env_addr;
+
+    env_addr = getenv ("DBUS_SYSTEM_BUS_ADDRESS");
+
+    if (env_addr == NULL || (*env_addr == 0))
+    {
+        env_addr = DBUS_SYSTEM_BUS_DEFAULT_ADDRESS;
+    }
+
+    conn = dbus_connection_open_private (env_addr, error);
+
+    if (!conn)
+        return NULL;
+
+    dbus_connection_set_exit_on_disconnect (conn, FALSE);
+
+    if (!dbus_bus_register (conn, error))
+    {
+        dbus_connection_close (conn);
+        dbus_connection_unref (conn);
+
+        return NULL;
+    }
+
+    return conn;
+}
+
+AvahiClient *avahi_client_new(const AvahiPoll *poll_api, AvahiClientCallback callback, void *userdata, int *ret_error) {
+    AvahiClient *client = NULL;
+    DBusError error;
+
+    dbus_error_init (&error);
+
+    if (!(client = avahi_new(AvahiClient, 1))) {
+        if (ret_error)
+            *ret_error = AVAHI_ERR_NO_MEMORY;
+        goto fail;
+    }
+
+    client->poll_api = poll_api;
+    client->error = AVAHI_OK;
+    client->callback = callback;
+    client->userdata = userdata;
+    client->state = AVAHI_CLIENT_DISCONNECTED;
+
+    client->host_name = NULL;
+    client->host_name_fqdn = NULL;
+    client->domain_name = NULL;
+    client->version_string = NULL;
+    client->local_service_cookie_valid = 0;
+    
+    AVAHI_LLIST_HEAD_INIT(AvahiEntryGroup, client->groups);
+    AVAHI_LLIST_HEAD_INIT(AvahiDomainBrowser, client->domain_browsers);
+    AVAHI_LLIST_HEAD_INIT(AvahiServiceBrowser, client->service_browsers);
+    AVAHI_LLIST_HEAD_INIT(AvahiServiceTypeBrowser, client->service_type_browsers);
+    AVAHI_LLIST_HEAD_INIT(AvahiServiceResolver, client->service_resolvers);
+    AVAHI_LLIST_HEAD_INIT(AvahiHostNameResolver, client->host_name_resolvers);
+    AVAHI_LLIST_HEAD_INIT(AvahiAddressResolver, client->address_resolvers);
+
+    if (!(client->bus = avahi_dbus_bus_get(&error)) ||
+        dbus_error_is_set (&error))
+        goto fail;
+
+    if (avahi_dbus_connection_glue(client->bus, poll_api) < 0) {
+        if (ret_error)
+            *ret_error = AVAHI_ERR_NO_MEMORY; /* Not optimal */
+        goto fail;
+    }
+
+    if (!dbus_connection_add_filter (client->bus, filter_func, client, NULL)) {
+        if (ret_error)
+            *ret_error = AVAHI_ERR_NO_MEMORY; 
+        goto fail;
+    }
+        
+    dbus_bus_add_match(
+        client->bus,
+        "type='signal', "
+        "interface='" AVAHI_DBUS_INTERFACE_SERVER "', "
+        "sender='" AVAHI_DBUS_NAME "', "
+        "path='" AVAHI_DBUS_PATH_SERVER "'",
+        &error);
+
+    if (dbus_error_is_set (&error))
+        goto fail;
+
+    dbus_bus_add_match (
+        client->bus,
+        "type='signal', "
+        "interface='" DBUS_INTERFACE_DBUS "', "
+        "sender='" DBUS_SERVICE_DBUS "', "
+        "path='" DBUS_PATH_DBUS "'",
+        &error);
+
+    if (dbus_error_is_set (&error))
+        goto fail;
+
+        dbus_bus_add_match (
+        client->bus,
+        "type='signal', "
+        "interface='" DBUS_INTERFACE_LOCAL "'",
+        &error);
+
+    if (dbus_error_is_set (&error))
+        goto fail;
+
+    if (!(dbus_bus_name_has_owner(client->bus, AVAHI_DBUS_NAME, &error)) ||
+        dbus_error_is_set(&error)) {
+
+        /* We free the error so its not set, that way the fail target
+         * will return the NO_DAEMON error rather than a DBUS error */
+        dbus_error_free (&error);
+
+        if (ret_error)
+            *ret_error = AVAHI_ERR_NO_DAEMON;
+        
+        goto fail;
+    }
+
+    if (check_version(client, ret_error) < 0)
+        goto fail;
+
+    if (get_server_state(client, ret_error) < 0)
+        goto fail;
+
+    return client;
+
+fail:
+
+    if (client)
+        avahi_client_free(client);
+
+    if (dbus_error_is_set(&error)) {
+
+        if (ret_error)
+            *ret_error = avahi_error_dbus_to_number(error.name);
+        
+        dbus_error_free(&error);
+    }
+        
+    return NULL;
+}
+
+void avahi_client_free(AvahiClient *client) {
+    assert(client);
+
+    while (client->groups)
+        avahi_entry_group_free(client->groups);
+
+    while (client->domain_browsers)
+        avahi_domain_browser_free(client->domain_browsers);
+
+    while (client->service_browsers)
+        avahi_service_browser_free(client->service_browsers);
+
+    while (client->service_type_browsers)
+        avahi_service_type_browser_free(client->service_type_browsers);
+
+    while (client->service_resolvers)
+        avahi_service_resolver_free(client->service_resolvers);
+
+    if (client->bus) {
+        dbus_connection_disconnect(client->bus);
+        dbus_connection_unref(client->bus);
+    }
+
+    avahi_free(client->version_string);
+    avahi_free(client->host_name);
+    avahi_free(client->host_name_fqdn);
+    avahi_free(client->domain_name);
+    
+    avahi_free(client);
+}
+
+static char* avahi_client_get_string_reply_and_block (AvahiClient *client, const char *method, const char *param) {
+    DBusMessage *message = NULL, *reply = NULL;
+    DBusError error;
+    char *ret, *n;
+
+    assert(client);
+    assert(method);
+
+    dbus_error_init (&error);
+
+    if (!(message = dbus_message_new_method_call (AVAHI_DBUS_NAME, AVAHI_DBUS_PATH_SERVER, AVAHI_DBUS_INTERFACE_SERVER, method))) {
+        avahi_client_set_errno(client, AVAHI_ERR_NO_MEMORY);
+        goto fail;
+    }
+
+    if (param) {
+        if (!dbus_message_append_args (message, DBUS_TYPE_STRING, &param, DBUS_TYPE_INVALID)) {
+            avahi_client_set_errno (client, AVAHI_ERR_NO_MEMORY);
+            goto fail;
+        }
+    }
+    
+    reply = dbus_connection_send_with_reply_and_block (client->bus, message, -1, &error);
+
+    if (!reply || dbus_error_is_set (&error))
+        goto fail;
+
+    if (!dbus_message_get_args (reply, &error, DBUS_TYPE_STRING, &ret, DBUS_TYPE_INVALID) ||
+        dbus_error_is_set (&error))
+        goto fail;
+    
+    if (!(n = avahi_strdup(ret))) {
+        avahi_client_set_errno(client, AVAHI_ERR_NO_MEMORY);
+        goto fail;
+    }
+
+    dbus_message_unref(message);
+    dbus_message_unref(reply);
+    
+    return n;
+
+fail:
+
+    if (message)
+        dbus_message_unref(message);
+    if (reply)
+        dbus_message_unref(reply);
+    
+    if (dbus_error_is_set(&error)) {
+        avahi_client_set_dbus_error(client, &error);
+        dbus_error_free(&error);
+    }
+
+    return NULL;
+}
+
+const char* avahi_client_get_version_string (AvahiClient *client) {
+    assert(client);
+
+    if (client->state == AVAHI_CLIENT_DISCONNECTED) {
+        avahi_client_set_errno(client, AVAHI_ERR_BAD_STATE);
+        return NULL;
+    }
+
+    if (!client->version_string)
+        client->version_string = avahi_client_get_string_reply_and_block(client, "GetVersionString", NULL);
+
+    return client->version_string;
+}
+
+const char* avahi_client_get_domain_name (AvahiClient *client) {
+    assert(client);
+
+    if (client->state == AVAHI_CLIENT_DISCONNECTED) {
+        avahi_client_set_errno(client, AVAHI_ERR_BAD_STATE);
+        return NULL;
+    }
+
+    if (!client->domain_name)
+        client->domain_name = avahi_client_get_string_reply_and_block(client, "GetDomainName", NULL);
+    
+    return client->domain_name;
+}
+
+const char* avahi_client_get_host_name (AvahiClient *client) {
+    assert(client);
+    
+    if (client->state == AVAHI_CLIENT_DISCONNECTED) {
+        avahi_client_set_errno(client, AVAHI_ERR_BAD_STATE);
+        return NULL;
+    }
+
+    if (!client->host_name)
+        client->host_name = avahi_client_get_string_reply_and_block(client, "GetHostName", NULL);
+    
+    return client->host_name;
+}
+
+const char* avahi_client_get_host_name_fqdn (AvahiClient *client) {
+    assert(client);
+
+    if (client->state == AVAHI_CLIENT_DISCONNECTED) {
+        avahi_client_set_errno(client, AVAHI_ERR_BAD_STATE);
+        return NULL;
+    }
+    
+    if (!client->host_name_fqdn)
+        client->host_name_fqdn = avahi_client_get_string_reply_and_block(client, "GetHostNameFqdn", NULL);
+
+    return client->host_name_fqdn;
+}
+
+AvahiClientState avahi_client_get_state(AvahiClient *client) {
+    assert(client);
+
+    return client->state;
+}
+
+int avahi_client_errno(AvahiClient *client) {
+    assert(client);
+    
+    return client->error;
+}
+
+/* Just for internal use */
+int avahi_client_simple_method_call(AvahiClient *client, const char *path, const char *interface, const char *method) {
+    DBusMessage *message = NULL, *reply = NULL;
+    DBusError error;
+    int r = AVAHI_OK;
+    
+    dbus_error_init(&error);
+
+    assert(client);
+    assert(path);
+    assert(interface);
+    assert(method);
+    
+    if (!(message = dbus_message_new_method_call(AVAHI_DBUS_NAME, path, interface, method))) {
+        r = avahi_client_set_errno(client, AVAHI_ERR_NO_MEMORY);
+        goto fail;
+    }
+        
+    if (!(reply = dbus_connection_send_with_reply_and_block(client->bus, message, -1, &error)) ||
+        dbus_error_is_set (&error)) {
+        r = avahi_client_set_errno(client, AVAHI_ERR_DBUS_ERROR);
+        goto fail;
+    }
+    
+    if (!dbus_message_get_args(reply, &error, DBUS_TYPE_INVALID) ||
+        dbus_error_is_set (&error)) {
+        r = avahi_client_set_errno(client, AVAHI_ERR_DBUS_ERROR);
+        goto fail;
+    }
+
+    dbus_message_unref(message);
+    dbus_message_unref(reply);
+
+    return AVAHI_OK;
+    
+fail:
+    if (dbus_error_is_set(&error)) {
+        r = avahi_client_set_dbus_error(client, &error);
+        dbus_error_free(&error);
+    }
+
+    if (message)
+        dbus_message_unref(message);
+
+    if (reply)
+        dbus_message_unref(reply);
+
+    return r;
+}
+
+uint32_t avahi_client_get_local_service_cookie(AvahiClient *client) {
+    DBusMessage *message = NULL, *reply = NULL;
+    DBusError error;
+    assert(client);
+
+    if (client->state == AVAHI_CLIENT_DISCONNECTED) {
+        avahi_client_set_errno(client, AVAHI_ERR_BAD_STATE);
+        return AVAHI_SERVICE_COOKIE_INVALID;
+    }
+
+    if (client->local_service_cookie_valid)
+        return client->local_service_cookie;
+
+    dbus_error_init (&error);
+
+    if (!(message = dbus_message_new_method_call(AVAHI_DBUS_NAME, AVAHI_DBUS_PATH_SERVER, AVAHI_DBUS_INTERFACE_SERVER, "GetLocalServiceCookie"))) {
+        avahi_client_set_errno(client, AVAHI_ERR_NO_MEMORY);
+        goto fail;
+    }
+
+    reply = dbus_connection_send_with_reply_and_block (client->bus, message, -1, &error);
+
+    if (!reply || dbus_error_is_set (&error))
+        goto fail;
+
+    if (!dbus_message_get_args (reply, &error, DBUS_TYPE_UINT32, &client->local_service_cookie, DBUS_TYPE_INVALID) ||
+        dbus_error_is_set (&error))
+        goto fail;
+    
+    dbus_message_unref(message);
+    dbus_message_unref(reply);
+
+    client->local_service_cookie_valid = 1;
+    return client->local_service_cookie;
+
+fail:
 
-    tmp = malloc (sizeof (AvahiClient));
+    if (message)
+        dbus_message_unref(message);
+    if (reply)
+        dbus_message_unref(reply);
+    
+    if (dbus_error_is_set(&error)) {
+        avahi_client_set_dbus_error(client, &error);
+        dbus_error_free(&error);
+    }
 
-    return tmp;
+    return AVAHI_SERVICE_COOKIE_INVALID;
 }