Re: [PATCH v9 3/3] qapi/monitor: allow VNC display id in set/expire_password

[Markus Armbruster <armbru@redhat.com>]

Fabian Ebner <f.ebner@proxmox.com> writes:

> Am 25.02.22 um 12:34 schrieb Markus Armbruster:
>> Fabian Ebner <f.ebner@proxmox.com> writes:
>> 
>>> From: Stefan Reiter <s.reiter@proxmox.com>
>>>
>>> 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>
>> 
>> [...]
>> 
>>> diff --git a/qapi/ui.json b/qapi/ui.json
>>> index e112409211..4a13f883a3 100644
>>> --- a/qapi/ui.json
>>> +++ b/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.
>> 
>> Is this default equivalent to any value?  "The first" suggests it's not.
>> 
>
> The value will be NULL and QTAILQ_FIRST(&vnc_displays) is picked, which
> means the display defaults to the first display. But yeah, the value
> doesn't actually default to the id of the first display, it just behaves
> as if it did.

QAPI lets you give "absent" a meaning different from any value (because
it lets you distinguish "absent" from any value).  I prefer not to make
use of it.  But it's not wrong.  My Acked-by stands.