Slightly OT: Where are keycodes defined for emacs -nw in X-Windows?

[Alan Mackenzie<none@example.invalid>]

Emacs 21.1.

In X-windows (running on GNU/Linux) I start emacs with "emacs -nw".  If I
type up and [C-up], followed by C-h l `view-lossage', I see this:

up     produces    ESC O A
[C-up] produces    ESC [ 2 4 ~

However, my Emacs isn't set up to handle the [C-up] event-sequence.  It
would seem I need to enhance my function-key-map somehow.

Searching the info pages brought me to the page "Terminal Specific" in
the Elisp manual.  Checking the environment variable TERM brought me to
the initalisation file ...../lisp/term/xterm.el.  In this file, only a
small number (21) of function keys are defined, none of them with
modifiers (i.e. C- M- S- ....).

Two questions:

Where on X is the file which defines the relevant keytable, and what's
the name of the function in X which loads such a table (analogues of
/etc/default.keytab and loadkeys for the Linux console)?

Is there a better file already in existence than the above xterm.el, one
that copes with _all_ keys with _all_ combinations of modifiers? 

Thanks in advance!

-- 
Alan Mackenzie (Munich, Germany)
Email: aacm@muuc.dee; to decode, wherever there is a repeated letter
(like "aa"), remove half of them (leaving, say, "a").