Am Donnerstag, 21. November 2002 11:41 schrieb Olaf Kirch:
On Thu, Nov 21, 2002 at 10:21:01AM +0100, Emmerich Eggler wrote:
file" ? Does the . belong to the username or is it the username-group delimiter?
Chown is a userland program that does (stupidly) check this, but the kernel doesn't care about chown-syntax.
User names are purely a user land feature too. The kernel doesn't care about user names.
Can you elaborate on this? I just added a user called "me.too" on a SuSE 8.1 by editing /etc/passwd and /etc/shadow and su'ed to this user. I'd say, it still works and works as expected ;-)
Of course, you can add almost anything to /etc/passwd, as long your user name doesn't contain a colon. But what is "works as expected"? Did you run a comprehensive test suite over all 5000 packages or so that come with SuSE Linux? If so, please talk to our Q&A department, I'm sure they'll be very interested :)
*grin* No, I didn't, of course.
There are certain conventions in the Unix world, and while it's hard to justify them in detail it's a good idea to adhere to them nevertheless.
I agree: but we're on thin ice here. We can hardly know all the established conventions and therefor follow them. Again: my position is: if a dot is a valid character for a username, I should be able to use it. If it is wrong, the system __itself__ should consider this account as invalid (not any of the userland programs, where other programs and the kernel happily accept such names). Actually, we could have found a desing flaw of UNIX like systems. ;-)
You can add a user name of ";-)" to /etc/passwd and that may even work for a surprising number of applications - but there will be the odd application that was coded with the assumption that if it's not alphanumerics, it's not a user name.
sic (design flaw). Bye Emmerich
Olaf
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