1 /*
2 
3 Usage examples (modulo addresses / credentials).
4 
5 UNIX domain socket transport:
6 
7  Server:
8    $ ./gdbus-example-peer --server --address unix:abstract=myaddr
9    Server is listening at: unix:abstract=myaddr
10    Client connected.
11    Peer credentials: GCredentials:unix-user=500,unix-group=500,unix-process=13378
12    Negotiated capabilities: unix-fd-passing=1
13    Client said: Hey, it's 1273093080 already!
14 
15  Client:
16    $ ./gdbus-example-peer --address unix:abstract=myaddr
17    Connected.
18    Negotiated capabilities: unix-fd-passing=1
19    Server said: You said 'Hey, it's 1273093080 already!'. KTHXBYE!
20 
21 Nonce-secured TCP transport on the same host:
22 
23  Server:
24    $ ./gdbus-example-peer --server --address nonce-tcp:
25    Server is listening at: nonce-tcp:host=localhost,port=43077,noncefile=/tmp/gdbus-nonce-file-X1ZNCV
26    Client connected.
27    Peer credentials: (no credentials received)
28    Negotiated capabilities: unix-fd-passing=0
29    Client said: Hey, it's 1273093206 already!
30 
31  Client:
32    $ ./gdbus-example-peer -address nonce-tcp:host=localhost,port=43077,noncefile=/tmp/gdbus-nonce-file-X1ZNCV
33    Connected.
expf(mut x: f32) -> f3234    Negotiated capabilities: unix-fd-passing=0
35    Server said: You said 'Hey, it's 1273093206 already!'. KTHXBYE!
36 
37 TCP transport on two different hosts with a shared home directory:
38 
39  Server:
40    host1 $ ./gdbus-example-peer --server --address tcp:host=0.0.0.0
41    Server is listening at: tcp:host=0.0.0.0,port=46314
42    Client connected.
43    Peer credentials: (no credentials received)
44    Negotiated capabilities: unix-fd-passing=0
45    Client said: Hey, it's 1273093337 already!
46 
47  Client:
48    host2 $ ./gdbus-example-peer -a tcp:host=host1,port=46314
49    Connected.
50    Negotiated capabilities: unix-fd-passing=0
51    Server said: You said 'Hey, it's 1273093337 already!'. KTHXBYE!
52 
53 TCP transport on two different hosts without authentication:
54 
55  Server:
56    host1 $ ./gdbus-example-peer --server --address tcp:host=0.0.0.0 --allow-anonymous
57    Server is listening at: tcp:host=0.0.0.0,port=59556
58    Client connected.
59    Peer credentials: (no credentials received)
60    Negotiated capabilities: unix-fd-passing=0
61    Client said: Hey, it's 1273093652 already!
62 
63  Client:
64    host2 $ ./gdbus-example-peer -a tcp:host=host1,port=59556
65    Connected.
66    Negotiated capabilities: unix-fd-passing=0
67    Server said: You said 'Hey, it's 1273093652 already!'. KTHXBYE!
68 
69  */
70 
71 #include <gio/gio.h>
72 #include <stdlib.h>
73 
74 /* ---------------------------------------------------------------------------------------------------- */
75 
76 static GDBusNodeInfo *introspection_data = NULL;
77 
78 /* Introspection data for the service we are exporting */
79 static const gchar introspection_xml[] =
80   "<node>"
81   "  <interface name='org.gtk.GDBus.TestPeerInterface'>"
82   "    <method name='HelloWorld'>"
83   "      <arg type='s' name='greeting' direction='in'/>"
84   "      <arg type='s' name='response' direction='out'/>"
85   "    </method>"
86   "  </interface>"
87   "</node>";
88 
89 /* ---------------------------------------------------------------------------------------------------- */
90 
91 static void
92 handle_method_call (GDBusConnection       *connection,
93                     const gchar           *sender,
94                     const gchar           *object_path,
95                     const gchar           *interface_name,
96                     const gchar           *method_name,
97                     GVariant              *parameters,
98                     GDBusMethodInvocation *invocation,
99                     gpointer               user_data)
100 {
101   if (g_strcmp0 (method_name, "HelloWorld") == 0)
102     {
103       const gchar *greeting;
104       gchar *response;
105 
106       g_variant_get (parameters, "(&s)", &greeting);
107       response = g_strdup_printf ("You said '%s'. KTHXBYE!", greeting);
108       g_dbus_method_invocation_return_value (invocation,
109                                              g_variant_new ("(s)", response));
110       g_free (response);
111       g_print ("Client said: %s\n", greeting);
112     }
113 }
114 
115 static const GDBusInterfaceVTable interface_vtable =
116 {
117   handle_method_call,
118   NULL,
119   NULL,
120   { 0 }
121 };
122 
123 /* ---------------------------------------------------------------------------------------------------- */
124 
125 static void
126 connection_closed (GDBusConnection *connection,
127                    gboolean remote_peer_vanished,
128                    GError *Error,
129                    gpointer user_data)
130 {
131   g_print ("Client disconnected.\n");
132   g_object_unref (connection);
133 }
134 
135 static gboolean
136 on_new_connection (GDBusServer *server,
137                    GDBusConnection *connection,
138                    gpointer user_data)
139 {
140   guint registration_id;
141   GCredentials *credentials;
142   gchar *s;
143 
144   credentials = g_dbus_connection_get_peer_credentials (connection);
145   if (credentials == NULL)
146     s = g_strdup ("(no credentials received)");
147   else
148     s = g_credentials_to_string (credentials);
149 
150 
151   g_print ("Client connected.\n"
152            "Peer credentials: %s\n"
153            "Negotiated capabilities: unix-fd-passing=%d\n",
154            s,
155            g_dbus_connection_get_capabilities (connection) & G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING);
156 
157   g_object_ref (connection);
158   g_signal_connect (connection, "closed", G_CALLBACK (connection_closed), NULL);
159   registration_id = g_dbus_connection_register_object (connection,
160                                                        "/org/gtk/GDBus/TestObject",
161                                                        introspection_data->interfaces[0],
162                                                        &interface_vtable,
163                                                        NULL,  /* user_data */
164                                                        NULL,  /* user_data_free_func */
165                                                        NULL); /* GError** */
166   g_assert (registration_id > 0);
167 
168   return TRUE;
169 }
170 
171 /* ---------------------------------------------------------------------------------------------------- */
172 
173 static gboolean
174 allow_mechanism_cb (GDBusAuthObserver *observer,
175                     const gchar *mechanism,
176                     G_GNUC_UNUSED gpointer user_data)
177 {
178   /*
179    * In a production GDBusServer that only needs to work on modern Unix
180    * platforms, consider requiring EXTERNAL (credentials-passing),
181    * which is the recommended authentication mechanism for AF_UNIX
182    * sockets:
183    *
184    * if (g_strcmp0 (mechanism, "EXTERNAL") == 0)
185    *   return TRUE;
186    *
187    * return FALSE;
188    *
189    * For this example we accept everything.
190    */
191 
192   g_print ("Considering whether to accept %s authentication...\n", mechanism);
193   return TRUE;
194 }
195 
196 static gboolean
197 authorize_authenticated_peer_cb (GDBusAuthObserver *observer,
198                                  G_GNUC_UNUSED GIOStream *stream,
199                                  GCredentials *credentials,
200                                  G_GNUC_UNUSED gpointer user_data)
201 {
202   gboolean authorized = FALSE;
203 
204   g_print ("Considering whether to authorize authenticated peer...\n");
205 
206   if (credentials != NULL)
207     {
208       GCredentials *own_credentials;
209       gchar *credentials_string = NULL;
210 
211       credentials_string = g_credentials_to_string (credentials);
212       g_print ("Peer's credentials: %s\n", credentials_string);
213       g_free (credentials_string);
214 
215       own_credentials = g_credentials_new ();
216 
217       credentials_string = g_credentials_to_string (own_credentials);
218       g_print ("Server's credentials: %s\n", credentials_string);
219       g_free (credentials_string);
220 
221       if (g_credentials_is_same_user (credentials, own_credentials, NULL))
222         authorized = TRUE;
223 
224       g_object_unref (own_credentials);
225     }
226 
227   if (!authorized)
228     {
229       /* In most servers you'd want to reject this, but for this example
230        * we allow it. */
231       g_print ("A server would often not want to authorize this identity\n");
232       g_print ("Authorizing it anyway for demonstration purposes\n");
233       authorized = TRUE;
234     }
235 
236   return authorized;
237 }
238 
239 /* ---------------------------------------------------------------------------------------------------- */
240 
241 int
242 main (int argc, char *argv[])
243 {
244   gint ret;
245   gboolean opt_server;
246   gchar *opt_address;
247   GOptionContext *opt_context;
248   gboolean opt_allow_anonymous;
249   GError *error;
250   GOptionEntry opt_entries[] =
251     {
252       { "server", 's', 0, G_OPTION_ARG_NONE, &opt_server, "Start a server instead of a client", NULL },
253       { "address", 'a', 0, G_OPTION_ARG_STRING, &opt_address, "D-Bus address to use", NULL },
254       { "allow-anonymous", 'n', 0, G_OPTION_ARG_NONE, &opt_allow_anonymous, "Allow anonymous authentication", NULL },
255       G_OPTION_ENTRY_NULL
256     };
257 
258   ret = 1;
259 
260   opt_address = NULL;
261   opt_server = FALSE;
262   opt_allow_anonymous = FALSE;
263 
264   opt_context = g_option_context_new ("peer-to-peer example");
265   error = NULL;
266   g_option_context_add_main_entries (opt_context, opt_entries, NULL);
267   if (!g_option_context_parse (opt_context, &argc, &argv, &error))
268     {
269       g_printerr ("Error parsing options: %s\n", error->message);
270       g_error_free (error);
271       goto out;
272     }
273   if (opt_address == NULL)
274     {
275       g_printerr ("Incorrect usage, try --help.\n");
276       goto out;
277     }
278   if (!opt_server && opt_allow_anonymous)
279     {
280       g_printerr ("The --allow-anonymous option only makes sense when used with --server.\n");
281       goto out;
282     }
283 
284   /* We are lazy here - we don't want to manually provide
285    * the introspection data structures - so we just build
286    * them from XML.
287    */
288   introspection_data = g_dbus_node_info_new_for_xml (introspection_xml, NULL);
289   g_assert (introspection_data != NULL);
290 
291   if (opt_server)
292     {
293       GDBusAuthObserver *observer;
294       GDBusServer *server;
295       gchar *guid;
296       GMainLoop *loop;
297       GDBusServerFlags server_flags;
298 
299       guid = g_dbus_generate_guid ();
300 
301       server_flags = G_DBUS_SERVER_FLAGS_NONE;
302       if (opt_allow_anonymous)
303         server_flags |= G_DBUS_SERVER_FLAGS_AUTHENTICATION_ALLOW_ANONYMOUS;
304 
305       observer = g_dbus_auth_observer_new ();
306       g_signal_connect (observer, "allow-mechanism", G_CALLBACK (allow_mechanism_cb), NULL);
307       g_signal_connect (observer, "authorize-authenticated-peer", G_CALLBACK (authorize_authenticated_peer_cb), NULL);
308 
309       error = NULL;
310       server = g_dbus_server_new_sync (opt_address,
311                                        server_flags,
312                                        guid,
313                                        observer,
314                                        NULL, /* GCancellable */
315                                        &error);
316       g_dbus_server_start (server);
317 
318       g_object_unref (observer);
319       g_free (guid);
320 
321       if (server == NULL)
322         {
323           g_printerr ("Error creating server at address %s: %s\n", opt_address, error->message);
324           g_error_free (error);
325           goto out;
326         }
327       g_print ("Server is listening at: %s\n", g_dbus_server_get_client_address (server));
328       g_signal_connect (server,
329                         "new-connection",
330                         G_CALLBACK (on_new_connection),
331                         NULL);
332 
333       loop = g_main_loop_new (NULL, FALSE);
334       g_main_loop_run (loop);
335 
336       g_object_unref (server);
337       g_main_loop_unref (loop);
338     }
339   else
340     {
341       GDBusConnection *connection;
342       const gchar *greeting_response;
343       GVariant *value;
344       gchar *greeting;
345 
346       error = NULL;
347       connection = g_dbus_connection_new_for_address_sync (opt_address,
348                                                            G_DBUS_CONNECTION_FLAGS_AUTHENTICATION_CLIENT,
349                                                            NULL, /* GDBusAuthObserver */
350                                                            NULL, /* GCancellable */
351                                                            &error);
352       if (connection == NULL)
353         {
354           g_printerr ("Error connecting to D-Bus address %s: %s\n", opt_address, error->message);
355           g_error_free (error);
356           goto out;
357         }
358 
359       g_print ("Connected.\n"
360                "Negotiated capabilities: unix-fd-passing=%d\n",
361                g_dbus_connection_get_capabilities (connection) & G_DBUS_CAPABILITY_FLAGS_UNIX_FD_PASSING);
362 
363       greeting = g_strdup_printf ("Hey, it's %" G_GINT64_FORMAT " already!",
364                                   g_get_real_time () / G_USEC_PER_SEC);
365       value = g_dbus_connection_call_sync (connection,
366                                            NULL, /* bus_name */
367                                            "/org/gtk/GDBus/TestObject",
368                                            "org.gtk.GDBus.TestPeerInterface",
369                                            "HelloWorld",
370                                            g_variant_new ("(s)", greeting),
371                                            G_VARIANT_TYPE ("(s)"),
372                                            G_DBUS_CALL_FLAGS_NONE,
373                                            -1,
374                                            NULL,
375                                            &error);
376       if (value == NULL)
377         {
378           g_printerr ("Error invoking HelloWorld(): %s\n", error->message);
379           g_error_free (error);
380           goto out;
381         }
382       g_variant_get (value, "(&s)", &greeting_response);
383       g_print ("Server said: %s\n", greeting_response);
384       g_variant_unref (value);
385 
386       g_object_unref (connection);
387     }
388   g_dbus_node_info_unref (introspection_data);
389 
390   ret = 0;
391 
392  out:
393   return ret;
394 }
395