Re: [PATCH v6 3/5] qapi/monitor: allow VNC display id in set/expire_password

[Markus Armbruster <armbru@redhat.com>]

Stefan Reiter <s.reiter@proxmox.com> writes:

> 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.
>
> Suggested-by: Markus Armbruster <armbru@redhat.com>
> Signed-off-by: Stefan Reiter <s.reiter@proxmox.com>
> ---
>  hmp-commands.hx    |  24 +++++-----
>  monitor/hmp-cmds.c |  51 +++++++++++++++------
>  monitor/qmp-cmds.c |  36 ++++++---------
>  qapi/ui.json       | 112 +++++++++++++++++++++++++++++++++++----------
>  4 files changed, 154 insertions(+), 69 deletions(-)
>
> diff --git a/hmp-commands.hx b/hmp-commands.hx
> index cf723c69ac..9fbb207b35 100644
> --- a/hmp-commands.hx
> +++ b/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:-dV,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:-dV",
> +        .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.
> diff --git a/monitor/hmp-cmds.c b/monitor/hmp-cmds.c
> index b8abe69609..daa4a8e106 100644
> --- a/monitor/hmp-cmds.c
> +++ b/monitor/hmp-cmds.c
> @@ -1451,26 +1451,39 @@ 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 = g_strdup(password),
> +        .u.vnc.display = NULL,
> +    };
> +
> +    opts.protocol = qapi_enum_parse(&DisplayProtocol_lookup, protocol,
> +                                    DISPLAY_PROTOCOL_VNC, &err);
>      if (err) {
>          goto out;
>      }
>  
> -    conn = qapi_enum_parse(&SetPasswordAction_lookup, connected,
> -                           SET_PASSWORD_ACTION_KEEP, &err);
> -    if (err) {
> -        goto out;
> +    if (opts.protocol == DISPLAY_PROTOCOL_VNC) {
> +        opts.u.vnc.has_display = !!display;
> +        opts.u.vnc.display = g_strdup(display);
> +    } else if (opts.protocol == DISPLAY_PROTOCOL_SPICE) {
> +        opts.u.spice.has_connected = !!connected;
> +        opts.u.spice.connected =
> +            qapi_enum_parse(&SetPasswordAction_lookup, connected,
> +                            SET_PASSWORD_ACTION_KEEP, &err);
> +        if (err) {
> +            goto out;
> +        }
>      }
>  
> -    qmp_set_password(proto, password, !!connected, conn, &err);
> +    qmp_set_password(&opts, &err);
>  
>  out:
> +    g_free(opts.password);
> +    g_free(opts.u.vnc.display);

Uh-oh...

For DISPLAY_PROTOCOL_SPICE, we execute

           .u.vnc.display = NULL,
           opts.u.spice.has_connected = !!connected;
           opts.u.spice.connected =
               qapi_enum_parse(&SetPasswordAction_lookup, connected,
                               SET_PASSWORD_ACTION_KEEP, &err);
           opts.u.vnc.has_display = !!display;
       g_free(opts.u.vnc.display);

The assignments to opts.u.spice.has_connected and opts.u.spice_connected
clobber opts.u.vnc.display.

The simplest fix is to pass @display directly.  Precedence:
hmp_drive_mirror().

Do the same for @password, of course.

>      hmp_handle_error(mon, err);
>  }
>  
> @@ -1478,18 +1491,30 @@ 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 = g_strdup(whenstr),
> +        .u.vnc.display = NULL,
> +    };
> +
> +    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 = g_strdup(display);
> +    }

Use of -d with spice are silently ignored.  Do we care?  Same for
hmp_set_password() above.

> +
> +    qmp_expire_password(&opts, &err);
>  
>  out:
> +    g_free(opts.time);
> +    g_free(opts.u.vnc.display);

No uh-oh here, since opts.u.vnc is actually the only member of opts.u.
Still, let's pass @time and @display directly for consistency and
robustness.

>      hmp_handle_error(mon, err);
>  }
>  

[...]