Add SPICE support to add_client monitor command

With the acceptance of some new APIs to libspice-server.so it
is possible to add support for SPICE to the 'add_client'
monitor command, bringing parity with VNC. Since SPICE can
use TLS or plain connections, the command also gains a new
'tls' parameter to specify whether TLS should be attempted
on the injected client sockets.

This new feature is only enabled if building against a
libspice-server >= 0.10.1

* qmp-commands.hx: Add 'tls' parameter & missing doc for
  'skipauth' parameter
* monitor.c: Wire up SPICE for 'add_client' command
* ui/qemu-spice.h, ui/spice-core.c: Add qemu_spice_display_add_client
  API to wire up from monitor

[1] http://cgit.freedesktop.org/spice/spice/commit/server/spice.h?id=d55b68b6b44f2499278fa860fb47ff22f5011faa
    http://cgit.freedesktop.org/spice/spice/commit/server/spice.h?id=bd07dde530d9504e1cfe7ed5837fc00c26f36716

Changes in v3:
 - Added 'optional' flag to new parameters documented
 - Added no-op impl of qemu_spice_display_add_client when
   SPICE is disabled during build

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

monitor.c

@@ -823,13 +823,18 @@ static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_d
     CharDriverState *s;
 
     if (strcmp(protocol, "spice") == 0) {
+        int fd = monitor_get_fd(mon, fdname);
+        int skipauth = qdict_get_try_bool(qdict, "skipauth", 0);
+        int tls = qdict_get_try_bool(qdict, "tls", 0);
         if (!using_spice) {
             /* correct one? spice isn't a device ,,, */
             qerror_report(QERR_DEVICE_NOT_ACTIVE, "spice");
             return -1;
         }
-	qerror_report(QERR_ADD_CLIENT_FAILED);
-	return -1;
+        if (qemu_spice_display_add_client(fd, skipauth, tls) < 0) {
+            close(fd);
+        }
+        return 0;
 #ifdef CONFIG_VNC
     } else if (strcmp(protocol, "vnc") == 0) {
 	int fd = monitor_get_fd(mon, fdname);

qmp-commands.hx

@@ -910,8 +910,8 @@ EQMP
 
     {
         .name       = "add_client",
-        .args_type  = "protocol:s,fdname:s,skipauth:b?",
-        .params     = "protocol fdname skipauth",
+        .args_type  = "protocol:s,fdname:s,skipauth:b?,tls:b?",
+        .params     = "protocol fdname skipauth tls",
         .help       = "add a graphics client",
         .user_print = monitor_user_noop,
         .mhandler.cmd_new = add_graphics_client,
@@ -927,6 +927,8 @@ Arguments:
 
 - "protocol": protocol name (json-string)
 - "fdname": file descriptor name (json-string)
+- "skipauth": whether to skip authentication (json-bool, optional)
+- "tls": whether to perform TLS (json-bool, optional)
 
 Example:
 

ui/qemu-spice.h

@@ -33,6 +33,7 @@ void qemu_spice_init(void);
 void qemu_spice_input_init(void);
 void qemu_spice_audio_init(void);
 void qemu_spice_display_init(DisplayState *ds);
+int qemu_spice_display_add_client(int csock, int skipauth, int tls);
 int qemu_spice_add_interface(SpiceBaseInstance *sin);
 int qemu_spice_set_passwd(const char *passwd,
                           bool fail_if_connected, bool disconnect_if_connected);
@@ -68,6 +69,12 @@ static inline int qemu_spice_migrate_info(const char *h, int p, int t,
     return -1;
 }
 
+static inline int qemu_spice_display_add_client(int csock, int skipauth,
+                                                int tls)
+{
+    return -1;
+}
+
 #endif /* CONFIG_SPICE */
 
 #endif /* QEMU_SPICE_H */

ui/spice-core.c

@@ -747,6 +747,19 @@ int qemu_spice_set_pw_expire(time_t expires)
     return qemu_spice_set_ticket(false, false);
 }
 
+int qemu_spice_display_add_client(int csock, int skipauth, int tls)
+{
+#if SPICE_SERVER_VERSION >= 0x000a01
+    if (tls) {
+        return spice_server_add_ssl_client(spice_server, csock, skipauth);
+    } else {
+        return spice_server_add_client(spice_server, csock, skipauth);
+    }
+#else
+    return -1;
+#endif
+}
+
 static void spice_register_config(void)
 {
     qemu_add_opts(&qemu_spice_opts);