qapi: convert add_client

Also fixes a few issues while there:

 1. The fd returned by monitor_get_fd() leaks in most error conditions
 2. monitor_get_fd() return value is not checked. Best case we get
    an error that is not correctly reported, worse case one of the
    functions using the fd (with value of -1) will explode
 3. A few error conditions aren't reported
 4. We now "use up" @fdname always.  Before, it was left alone for
    invalid @protocol

Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>

monitor.c

@@ -944,45 +944,6 @@ static void do_trace_print_events(Monitor *mon)
     trace_print_events((FILE *)mon, &monitor_fprintf);
 }
 
-static int add_graphics_client(Monitor *mon, const QDict *qdict, QObject **ret_data)
-{
-    const char *protocol  = qdict_get_str(qdict, "protocol");
-    const char *fdname = qdict_get_str(qdict, "fdname");
-    CharDriverState *s;
-
-    if (strcmp(protocol, "spice") == 0) {
-        int fd = monitor_get_fd(mon, fdname, NULL);
-        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;
-        }
-        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, NULL);
-        int skipauth = qdict_get_try_bool(qdict, "skipauth", 0);
-	vnc_display_add_client(NULL, fd, skipauth);
-	return 0;
-#endif
-    } else if ((s = qemu_chr_find(protocol)) != NULL) {
-	int fd = monitor_get_fd(mon, fdname, NULL);
-	if (qemu_chr_add_client(s, fd) < 0) {
-	    qerror_report(QERR_ADD_CLIENT_FAILED);
-	    return -1;
-	}
-	return 0;
-    }
-
-    qerror_report(QERR_INVALID_PARAMETER, "protocol");
-    return -1;
-}
-
 static int client_migrate_info(Monitor *mon, const QDict *qdict,
                                MonitorCompletion cb, void *opaque)
 {

qapi-schema.json

@@ -32,6 +32,31 @@
             'DeviceNotActive', 'DeviceNotFound', 'KVMMissingCap',
             'MigrationExpected' ] }
 
+##
+# @add_client
+#
+# Allow client connections for VNC, Spice and socket based
+# character devices to be passed in to QEMU via SCM_RIGHTS.
+#
+# @protocol: protocol name. Valid names are "vnc", "spice" or the
+#            name of a character device (eg. from -chardev id=XXXX)
+#
+# @fdname: file descriptor name previously passed via 'getfd' command
+#
+# @skipauth: #optional whether to skip authentication. Only applies
+#            to "vnc" and "spice" protocols
+#
+# @tls: #optional whether to perform TLS. Only applies to the "spice"
+#       protocol
+#
+# Returns: nothing on success.
+#
+# Since: 0.14.0
+##
+{ 'command': 'add_client',
+  'data': { 'protocol': 'str', 'fdname': 'str', '*skipauth': 'bool',
+            '*tls': 'bool' } }
+
 ##
 # @NameInfo:
 #

qmp-commands.hx

@@ -1231,10 +1231,7 @@ EQMP
     {
         .name       = "add_client",
         .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,
+        .mhandler.cmd_new = qmp_marshal_input_add_client,
     },
 
 SQMP

qmp.c

@@ -479,3 +479,46 @@ CpuDefinitionInfoList *qmp_query_cpu_definitions(Error **errp)
     return arch_query_cpu_definitions(errp);
 }
 
+void qmp_add_client(const char *protocol, const char *fdname,
+                    bool has_skipauth, bool skipauth, bool has_tls, bool tls,
+                    Error **errp)
+{
+    CharDriverState *s;
+    int fd;
+
+    fd = monitor_get_fd(cur_mon, fdname, errp);
+    if (fd < 0) {
+        return;
+    }
+
+    if (strcmp(protocol, "spice") == 0) {
+        if (!using_spice) {
+            error_set(errp, QERR_DEVICE_NOT_ACTIVE, "spice");
+            close(fd);
+            return;
+        }
+        skipauth = has_skipauth ? skipauth : false;
+        tls = has_tls ? tls : false;
+        if (qemu_spice_display_add_client(fd, skipauth, tls) < 0) {
+            error_setg(errp, "spice failed to add client");
+            close(fd);
+        }
+        return;
+#ifdef CONFIG_VNC
+    } else if (strcmp(protocol, "vnc") == 0) {
+        skipauth = has_skipauth ? skipauth : false;
+        vnc_display_add_client(NULL, fd, skipauth);
+        return;
+#endif
+    } else if ((s = qemu_chr_find(protocol)) != NULL) {
+        if (qemu_chr_add_client(s, fd) < 0) {
+            error_setg(errp, "failed to add client");
+            close(fd);
+            return;
+        }
+        return;
+    }
+
+    error_setg(errp, "protocol '%s' is invalid", protocol);
+    close(fd);
+}