qapi/monitor: allow VNC display id in set/expire_password

It is possible to specify more than one VNC server on the command line,
either with an explicit ID or the auto-generated ones à la "default",
"vnc2", "vnc3", ...

It is not possible to change the password on one of these extra VNC
displays though. Fix this by adding a "display" parameter to the
"set_password" and "expire_password" QMP and HMP commands.

For HMP, the display is specified using the "-d" value flag.

For QMP, the schema is updated to explicitly express the supported
variants of the commands with protocol-discriminated unions.

Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
[FE: update "Since: " from 6.2 to 7.0
     make @connected a common member of @SetPasswordOptions]
Signed-off-by: Fabian Ebner <f.ebner@proxmox.com>
Message-Id: <20220225084949.35746-4-f.ebner@proxmox.com>
Acked-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

hmp-commands.hx

@@ -1514,33 +1514,35 @@ ERST
 
     {
         .name       = "set_password",
-        .args_type  = "protocol:s,password:s,connected:s?",
-        .params     = "protocol password action-if-connected",
+        .args_type  = "protocol:s,password:s,display:-ds,connected:s?",
+        .params     = "protocol password [-d display] [action-if-connected]",
         .help       = "set spice/vnc password",
         .cmd        = hmp_set_password,
     },
 
 SRST
-``set_password [ vnc | spice ] password [ action-if-connected ]``
-  Change spice/vnc password.  *action-if-connected* specifies what
-  should happen in case a connection is established: *fail* makes the
-  password change fail.  *disconnect* changes the password and
+``set_password [ vnc | spice ] password [ -d display ] [ action-if-connected ]``
+  Change spice/vnc password.  *display* can be used with 'vnc' to specify
+  which display to set the password on.  *action-if-connected* specifies
+  what should happen in case a connection is established: *fail* makes
+  the password change fail.  *disconnect* changes the password and
   disconnects the client.  *keep* changes the password and keeps the
   connection up.  *keep* is the default.
 ERST
 
     {
         .name       = "expire_password",
-        .args_type  = "protocol:s,time:s",
-        .params     = "protocol time",
+        .args_type  = "protocol:s,time:s,display:-ds",
+        .params     = "protocol time [-d display]",
         .help       = "set spice/vnc password expire-time",
         .cmd        = hmp_expire_password,
     },
 
 SRST
-``expire_password [ vnc | spice ]`` *expire-time*
-  Specify when a password for spice/vnc becomes
-  invalid. *expire-time* accepts:
+``expire_password [ vnc | spice ] expire-time [ -d display ]``
+  Specify when a password for spice/vnc becomes invalid.
+  *display* behaves the same as in ``set_password``.
+  *expire-time* accepts:
 
   ``now``
     Invalidate password instantly.

monitor/hmp-cmds.c

@@ -1396,24 +1396,33 @@ void hmp_set_password(Monitor *mon, const QDict *qdict)
 {
     const char *protocol  = qdict_get_str(qdict, "protocol");
     const char *password  = qdict_get_str(qdict, "password");
+    const char *display = qdict_get_try_str(qdict, "display");
     const char *connected = qdict_get_try_str(qdict, "connected");
     Error *err = NULL;
-    DisplayProtocol proto;
-    SetPasswordAction conn;
 
-    proto = qapi_enum_parse(&DisplayProtocol_lookup, protocol,
-                            DISPLAY_PROTOCOL_VNC, &err);
+    SetPasswordOptions opts = {
+        .password = (char *)password,
+        .has_connected = !!connected,
+    };
+
+    opts.connected = qapi_enum_parse(&SetPasswordAction_lookup, connected,
+                                     SET_PASSWORD_ACTION_KEEP, &err);
     if (err) {
         goto out;
     }
 
-    conn = qapi_enum_parse(&SetPasswordAction_lookup, connected,
-                           SET_PASSWORD_ACTION_KEEP, &err);
+    opts.protocol = qapi_enum_parse(&DisplayProtocol_lookup, protocol,
+                                    DISPLAY_PROTOCOL_VNC, &err);
     if (err) {
         goto out;
     }
 
-    qmp_set_password(proto, password, !!connected, conn, &err);
+    if (opts.protocol == DISPLAY_PROTOCOL_VNC) {
+        opts.u.vnc.has_display = !!display;
+        opts.u.vnc.display = (char *)display;
+    }
+
+    qmp_set_password(&opts, &err);
 
 out:
     hmp_handle_error(mon, err);
@@ -1423,16 +1432,25 @@ void hmp_expire_password(Monitor *mon, const QDict *qdict)
 {
     const char *protocol  = qdict_get_str(qdict, "protocol");
     const char *whenstr = qdict_get_str(qdict, "time");
+    const char *display = qdict_get_try_str(qdict, "display");
     Error *err = NULL;
-    DisplayProtocol proto;
 
-    proto = qapi_enum_parse(&DisplayProtocol_lookup, protocol,
-                            DISPLAY_PROTOCOL_VNC, &err);
+    ExpirePasswordOptions opts = {
+        .time = (char *)whenstr,
+    };
+
+    opts.protocol = qapi_enum_parse(&DisplayProtocol_lookup, protocol,
+                                    DISPLAY_PROTOCOL_VNC, &err);
     if (err) {
         goto out;
     }
 
-    qmp_expire_password(proto, whenstr, &err);
+    if (opts.protocol == DISPLAY_PROTOCOL_VNC) {
+        opts.u.vnc.has_display = !!display;
+        opts.u.vnc.display = (char *)display;
+    }
+
+    qmp_expire_password(&opts, &err);
 
 out:
     hmp_handle_error(mon, err);

monitor/qmp-cmds.c

@@ -168,35 +168,27 @@ void qmp_system_wakeup(Error **errp)
     qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER, errp);
 }
 
-void qmp_set_password(DisplayProtocol protocol, const char *password,
-                      bool has_connected, SetPasswordAction connected,
-                      Error **errp)
+void qmp_set_password(SetPasswordOptions *opts, Error **errp)
 {
-    int disconnect_if_connected = 0;
-    int fail_if_connected = 0;
     int rc;
 
-    if (has_connected) {
-        fail_if_connected = connected == SET_PASSWORD_ACTION_FAIL;
-        disconnect_if_connected = connected == SET_PASSWORD_ACTION_DISCONNECT;
-    }
-
-    if (protocol == DISPLAY_PROTOCOL_SPICE) {
+    if (opts->protocol == DISPLAY_PROTOCOL_SPICE) {
         if (!qemu_using_spice(errp)) {
             return;
         }
-        rc = qemu_spice.set_passwd(password, fail_if_connected,
-                                   disconnect_if_connected);
+        rc = qemu_spice.set_passwd(opts->password,
+                opts->connected == SET_PASSWORD_ACTION_FAIL,
+                opts->connected == SET_PASSWORD_ACTION_DISCONNECT);
     } else {
-        assert(protocol == DISPLAY_PROTOCOL_VNC);
-        if (fail_if_connected || disconnect_if_connected) {
+        assert(opts->protocol == DISPLAY_PROTOCOL_VNC);
+        if (opts->connected != SET_PASSWORD_ACTION_KEEP) {
             /* vnc supports "connected=keep" only */
             error_setg(errp, QERR_INVALID_PARAMETER, "connected");
             return;
         }
         /* Note that setting an empty password will not disable login through
          * this interface. */
-        rc = vnc_display_password(NULL, password);
+        rc = vnc_display_password(opts->u.vnc.display, opts->password);
     }
 
     if (rc != 0) {
@@ -204,11 +196,11 @@ void qmp_set_password(DisplayProtocol protocol, const char *password,
     }
 }
 
-void qmp_expire_password(DisplayProtocol protocol, const char *whenstr,
-                         Error **errp)
+void qmp_expire_password(ExpirePasswordOptions *opts, Error **errp)
 {
     time_t when;
     int rc;
+    const char *whenstr = opts->time;
 
     if (strcmp(whenstr, "now") == 0) {
         when = 0;
@@ -220,14 +212,14 @@ void qmp_expire_password(DisplayProtocol protocol, const char *whenstr,
         when = strtoull(whenstr, NULL, 10);
     }
 
-    if (protocol == DISPLAY_PROTOCOL_SPICE) {
+    if (opts->protocol == DISPLAY_PROTOCOL_SPICE) {
         if (!qemu_using_spice(errp)) {
             return;
         }
         rc = qemu_spice.set_pw_expire(when);
     } else {
-        assert(protocol == DISPLAY_PROTOCOL_VNC);
-        rc = vnc_display_pw_expire(NULL, when);
+        assert(opts->protocol == DISPLAY_PROTOCOL_VNC);
+        rc = vnc_display_pw_expire(opts->u.vnc.display, when);
     }
 
     if (rc != 0) {

qapi/ui.json

@@ -38,20 +38,47 @@
   'data': [ 'keep', 'fail', 'disconnect' ] }
 
 ##
-# @set_password:
+# @SetPasswordOptions:
 #
-# Sets the password of a remote display session.
+# Options for set_password.
 #
 # @protocol: - 'vnc' to modify the VNC server password
 #            - 'spice' to modify the Spice server password
 #
 # @password: the new password
 #
-# @connected: how to handle existing clients when changing the
-#             password.  If nothing is specified, defaults to 'keep'
-#             'fail' to fail the command if clients are connected
-#             'disconnect' to disconnect existing clients
-#             'keep' to maintain existing clients
+# @connected: How to handle existing clients when changing the
+#             password. If nothing is specified, defaults to 'keep'.
+#             For VNC, only 'keep' is currently implemented.
+#
+# Since: 7.0
+#
+##
+{ 'union': 'SetPasswordOptions',
+  'base': { 'protocol': 'DisplayProtocol',
+            'password': 'str',
+            '*connected': 'SetPasswordAction' },
+  'discriminator': 'protocol',
+  'data': { 'vnc': 'SetPasswordOptionsVnc' } }
+
+##
+# @SetPasswordOptionsVnc:
+#
+# Options for set_password specific to the VNC procotol.
+#
+# @display: The id of the display where the password should be changed.
+#           Defaults to the first.
+#
+# Since: 7.0
+#
+##
+{ 'struct': 'SetPasswordOptionsVnc',
+  'data': { '*display': 'str' } }
+
+##
+# @set_password:
+#
+# Set the password of a remote display server.
 #
 # Returns: - Nothing on success
 #          - If Spice is not enabled, DeviceNotFound
@@ -65,17 +92,15 @@
 # <- { "return": {} }
 #
 ##
-{ 'command': 'set_password',
-  'data': { 'protocol': 'DisplayProtocol',
-            'password': 'str',
-            '*connected': 'SetPasswordAction' } }
+{ 'command': 'set_password', 'boxed': true, 'data': 'SetPasswordOptions' }
 
 ##
-# @expire_password:
+# @ExpirePasswordOptions:
 #
-# Expire the password of a remote display server.
+# General options for expire_password.
 #
-# @protocol: the name of the remote display protocol 'vnc' or 'spice'
+# @protocol: - 'vnc' to modify the VNC server expiration
+#            - 'spice' to modify the Spice server expiration
 #
 # @time: when to expire the password.
 #
@@ -84,16 +109,45 @@
 #        - '+INT' where INT is the number of seconds from now (integer)
 #        - 'INT' where INT is the absolute time in seconds
 #
-# Returns: - Nothing on success
-#          - If @protocol is 'spice' and Spice is not active, DeviceNotFound
-#
-# Since: 0.14
-#
 # Notes: Time is relative to the server and currently there is no way to
 #        coordinate server time with client time.  It is not recommended to
 #        use the absolute time version of the @time parameter unless you're
 #        sure you are on the same machine as the QEMU instance.
 #
+# Since: 7.0
+#
+##
+{ 'union': 'ExpirePasswordOptions',
+  'base': { 'protocol': 'DisplayProtocol',
+            'time': 'str' },
+  'discriminator': 'protocol',
+  'data': { 'vnc': 'ExpirePasswordOptionsVnc' } }
+
+##
+# @ExpirePasswordOptionsVnc:
+#
+# Options for expire_password specific to the VNC procotol.
+#
+# @display: The id of the display where the expiration should be changed.
+#           Defaults to the first.
+#
+# Since: 7.0
+#
+##
+
+{ 'struct': 'ExpirePasswordOptionsVnc',
+  'data': { '*display': 'str' } }
+
+##
+# @expire_password:
+#
+# Expire the password of a remote display server.
+#
+# Returns: - Nothing on success
+#          - If @protocol is 'spice' and Spice is not active, DeviceNotFound
+#
+# Since: 0.14
+#
 # Example:
 #
 # -> { "execute": "expire_password", "arguments": { "protocol": "vnc",
@@ -101,9 +155,7 @@
 # <- { "return": {} }
 #
 ##
-{ 'command': 'expire_password',
-  'data': { 'protocol': 'DisplayProtocol',
-            'time': 'str' } }
+{ 'command': 'expire_password', 'boxed': true, 'data': 'ExpirePasswordOptions' }
 
 ##
 # @screendump: