QUERY: Legal characters in login names?

[fair at dual.UUCP]

Newsgroup: net.unix-wizards,net.bugs.usg
Subject: QUERY: Legal Characters in login names?


Does anyone know if there are any (published or unwritten) guidlines
for the makeup of a login name? Reason for this question: the USG
(Sys III and Sys V) accounting software seems to make the assumption
that only alphabetics or numerics, along with the character `$' (WHY?)
are legal. In fact, the code for acctcon1 (the connect accounting
processor) says something like:

if (isaplha(c) || isdigit(c) || c == '$')
	...
else
	barf		/* new C function */

We just added some login names with the `_' character in them and the
connect processing really did barf (the wtmp file was assumed to be
out of phase). In addition, the whole accounting system continues to
have headaches on 8-character logins.

So, what is the story? What is considered to be a valid login name,
and if the above fragment makes unreasonable assumptions, why are they
made (unanswerable question?).

For those are curious, this system is a UniSoft System III 68000.

	Mats D. Wichmann	Erik E. Fair

	{ucbvax,amd70,zehntel,unisoft,onyx,its}!dual!{fair,mats}
	Dual Systems Corporation, Berkeley, California