dhesi@bsu-cs.UUCP (Rahul Dhesi) (08/25/87)
Summary: Torture-testing the "screen" program, which allows multiple virtual terminals to be created, I found that it is possible to get spurious entries in /etc/utmp. Software: 4.3BSD straight from Berkeley, obtained around September 1986. Hardware: VAX-11/785. Symptoms: After a user logs out from a new login session that was running under control of "screen", the user's name is still in /etc/utmp and the "who" command will show the user still logged in. Repeat-By: 1. Invoke "screen". 2. Execute /bin/login by typing "/bin/login". 3. Log normally at the login prompt. 4. Log out normally. 5. Use the "who" or "w" command and observe that you are shown logged in twice. Comments: It's a bit disconcerting to be able to create an entry in /etc/utmp that doesn't seem to get removed. This confuses my timeout program, because it examines /etc/utmp to look for idle users. -- Rahul Dhesi UUCP: {ihnp4,seismo}!{iuvax,pur-ee}!bsu-cs!dhesi
net@tub.UUCP (08/26/87)
> Symptoms: > After a user logs out from a new login session that was running under > control of "screen", the user's name is still in /etc/utmp and > the "who" command will show the user still logged in. You didn't install "screen" with set-uid and owner root as explained in the README-file, the Makefile, and the BUGS-section of the manual page. If "screen" isn't granted write access to /etc/utmp it cannot remove the utmp-entry inserted by /bin/login. You can reproduce this ``bug in screen'' even without the help of "screen": Just run /bin/login on a random pseudo-tty without the help of friendly set-uid programs like "rlogind" or "screen" that clean up after you. -- Oliver Laumann, Technical University of Berlin, Germany. ...!pyramid!tub!net or net@TUB.BITNET "I have yet to see anything posted by Dhesi that was correct." --Doug Gwyn
dhesi@bsu-cs.UUCP (Rahul Dhesi) (09/01/87)
In article <49100001@tub.UUCP> net@tub.UUCP writes about my report that "screen" can leave behind ghosts in /etc/utmp: >You didn't install "screen" with set-uid and owner root as explained >in the README-file, the Makefile, and the BUGS-section of the manual page. > Oliver Laumann, Technical University of Berlin, Germany. > ...!pyramid!tub!net or net@TUB.BITNET But I did. -- Rahul Dhesi UUCP: {ihnp4,seismo}!{iuvax,pur-ee}!bsu-cs!dhesi