Some feature requests for guest consoles

[Andy Smith <andy@xxxxxxxxxxxxxx>]

Hi,

Mike H <mikeh@xxxxxxxxx> made a feature request in:

    https://lists.xenproject.org/archives/html/xen-users/2022-03/msg00009.html

for the Xen guest console as connected to with "xl console" to
correctly support the terminal size rather than always being 80x20.

Additionally I wondered about some other features:

- Ability to remap the "magic sysrq" key combination which is
  ctrl-o, and possibly disable it while leaving "xl sysrq" and
  /proc/sysrq-trigger in the guest generally working.

  Reason: guest administrators are often inexperienced with the
  details of Xen. ctrl-o is a bad choice because it's actually the
  "save buffer" shortcut in the popular editor nano. On more than
  one occasion I have had guest administrators be editing a file
  with nano on their console, they go to save it with ctrl-o which
  appears to do nothing (because Xen is waiting for the sysrq
  command that follows), so they do ctrl-o again which is taken as
  being command 'o' - immediate power off! I have had an emergency
  support ticket about this because "my guest randomly crashed while
  I was editing a file".

  I would therefore like to remap "magic sysrq" to something more
  obscure, or failing that disable it in guests as we/they will use
  "xl sysrq" instead.

A couple of other things which may already be possible but I don't
know how, so if anyone's done it maybe they could give hints:

- Systematically and automatically log all guest console activity to
  individual files without interfering with the ability to use "xl
  console"

- Somehow plumb the xenconsole pty to a web terminal like xterm.js

Thanks!
Andy