Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!seismo!mcvax!diku!olamb!kimcm From: kimcm@olamb.UUCP (Kim Chr. Madsen) Newsgroups: comp.unix.questions Subject: Re: Disabling logins under System V Message-ID: <298@olamb.UUCP> Date: Thu, 16-Jul-87 05:44:09 EDT Article-I.D.: olamb.298 Posted: Thu Jul 16 05:44:09 1987 Date-Received: Sat, 18-Jul-87 11:31:28 EDT References: <905@woton.UUCP> <256@axis.fr> Organization: AmbraSoft A/S (Denmark) Lines: 36 In article <256@axis.fr>, philip@axis.fr (Philip Peake) writes: > In article <905@woton.UUCP>, riddle@woton.UUCP (Prentiss Riddle ) writes: > > I am looking for some advice about the preferred way to temporarily > > disable all user logins under System V. What I want is something > > analogous to the BSD "/etc/nologin" file. > The easiest way that I can think of is to use /etc/profile. > Its much less dangerous than playing with /etc/passwd or > /etc/inittab. Except that it will not allways work - user's who are not running the /bin/sh or other shells that don't source the /etc/profile will not be hindered by this approach... The best way to do it is to use the init program to change the state of the system - use "init s" to go to single user-mode mount the /usr and other disks/partions you want to backup - do your backup and return to multiuser state again by calling "init 2". If you don't like this approach because you want to be able to login as a non-root account (or whatever reason) you can maintain two password files and have a shell-script switching between them when you change state to a user defined state (don't use init state 3 - it is used for network in SYSV release 3.0 and later, but use state 4) put the shell script in the directory /etc/rc4.d/ and return to state 2 when you're done with the backup. If you use the latter method remember to kill active user processes (if necessary) with the command /etc/killall - and don't forget to issue a warning to all users so they can log off the system gracefully before you'll have to kill them! Finally if you have the sources for /bin/login you can hack it to check whether /etc/nologin exists and if so prevent further logins. Kim Chr. Madsen.