etc/issue : undocumented, etc/dialups : undocumented etc..

[Ken Keirnan]

In article <538 at balaena.UUCP> wezel at balaena (Jos C. van Wezel) writes:
>
>Skimming tru my sysV manuals I came across the file /etc/issue, in the
>man pages for getty. However it is only mentioned, no description.
>I remember seeing somewhere it differentiated between several projects,
>and then echoed a specific line when getty started. No reasonable file
>format did the trick however, so I'd like to ask if anyone knows what
>format to use or else what the file is for.
>In my bin/login (I'm on a 3B2, V3.1) after an od I found the path:
>/etc/dialups. Now this isn't even in the manuals. Again where is it used
>for, and what is the format. Maybe it's a relic, but there no means for
>me to check that out.
>I'd be obliged with an answer.

Jos,  the printing of the contents of an "/etc/issue" file prior to
outputing the log on message is a compile time option for the "getty"
program.  Some vendors supply getty with the code compiled in, some (most?)
don't.  Speak with your System V vendor about this one.

Many recent versions of the System V "login" program support the (undocumented)
dialup password mechanism.  Two files are required for implementation of
this feature: "/etc/dialups" and "/etc/d_passwd".  The first file,
/etc/dialups, should contain a list of tty path names associated with
dial in lines (one per line in the form: /dev/ttyxx).  The second file,
/etc/d_passwd, consists of entries similar to those in /etc/passwd, but
the first field is the shell name (you can have different passwords for
each login shell), the second field is the password, and anything else
is comment:

		/bin/sh:<encrypted_password>:optional comments
		/bin/rsh:<encrypted_password>:optional comments

Note that even without the comments, the second colon is *required* for
login to parse the line correctly.  Since there is no handy dialup password
changing program, the easiest way to create passwords is to change the
password for an ordinary user login to the one for the dialup password,
then edit the encrypted password into the second field in /etc/d_passwd.

If you want all login shells (whatever their name) to use the same dialup
password, the only line required in d_passwd is one for the default shell
(usually /bin/sh) used by login.  Any other shell not found in d_passwd
will then use this default entry.

One more important note.  If you have incoming UUCP traffic, you probably
*won't* want a dialup password fouling up the works so make sure to
include a line in /etc/d_passwd as follows:

		/usr/lib/uucp/uucico::

One last caution.  There is a bug in some versions of login that support
dialup passwords that causes login to prompt for the dialup password even
when there isn't one.  In this case, typing just a carriage return in
response to the prompt will work, *but*, it will still cause UUCP to fail
when logging in.  Be sure to test for this bug.  If you have source for
login, it is an easy fix:  at the bottom of the dialpass() routine,
change:

	fclose(fp);
	return(gpass("Dialup Password:", defpass));

to:

	fclose(fp);
	if (defpass[0] == '\0')
		return(0);
	return(gpass("Dialup Password:", defpass));


Ken Keirnan
-- 

Ken Keirnan - Pacific Bell - {att,bellcore,sun,ames,pyramid}!pacbell!pbhyf!kjk
  San Ramon, California	                    kjk at pbhyf.PacBell.COM