bph@buengc.BU.EDU (Blair P. Houghton) (09/05/89)
When opening a new login window (pseudo-terminal in an X window running a shell enabled to run the login(1) program), as in xterm -ls -e login & (xterm(1X) from X11R2) the new window comes up and immediately does the login(1). Only, login(1) creates an entirely new set of environment variables, effectively ignoring the imported environment, and DISPLAY in particular. One can also no longer determine the DISPLAY variable by using tty(1) to look at whether one is at ttyv0 or ttyv1 (the display-consoles), because the terminal is a pty with the name of whichever was the next available pseudo-terminal, and any pty can get set to either of the two displays on these two-head GPX workstations. The question is, although I know the window is on this screen, and the X server knows the window is on this screen, how can I get the shell (csh(1)) to know which screen this window is on, in order to set DISPLAY (in $HOME/.login, for the benefit of this process' children), other than by prompting for that information from the user? /etc/gettytab(5) has this information in it so that getty(8) knows where to send the display-consoles, but it's tied again to knowing that you're using either ttyv0 or ttyv1, so that route is moot. Any assistance will be appreciated. Flame if you must: you know I would. :-) --Blair "Shell Script 101 has been cancelled for the fall semester due to the fact that the instructor is stumped on this one."
dce@Solbourne.COM (David Elliott) (09/06/89)
In article <4045@buengc.BU.EDU> bph@buengc.bu.edu (Blair P. Houghton) writes: >Only, login(1) creates an entirely new set of environment variables, >effectively ignoring the imported environment, and DISPLAY in particular. Yep, this is a real pain. I've seen a lot of solutions, but most end up asking the user or assuming no more than one rlogin. The only one I really like is one in which you can query xterm for the value of DISPLAY, but there are problems in doing this, so I use the following solution: 1. Instead of using the normal rlogin, I have in my path ~/.rlogin, which contains the same type of links as /usr/hosts (that is, links for each hostname and nickname to an rlogin program) and a command called rlogin, which is the following shell script: #!/bin/sh case "$DISPLAY" in "") ;; *) rm -f $HOME/.xdisplay echo "$DISPLAY" > $HOME/.xdisplay ;; esac case "$0" in *rlogin) ;; *) set "`basename $0`" ${1+"$@"} ;; esac exec /usr/ucb/rlogin ${1+"$@"} This results in creating a file called ~/.xdisplay which contains the value of DISPLAY. 2. In my .login, I have the following block of code: if ("$TERM" == "xterm") then if ($?DISPLAY) then : else setenv DISPLAY `getdisplay` endif switch ("$DISPLAY") case selene\:*: alias bitmap bitmap -nodashed -geometry '1024x850+20+20' breaksw ... That is, if my terminal type is xterm, then I want to get the DISPLAY variable if it isn't set already (i.e., I rlogin'ed instead of creating a new xterm directly on the client machine). The last bit is where I set up aliases and variables for specific servers. 3. In my personal bin directory, I have getdisplay: #!/bin/sh PATH=/bin:/usr/bin if [ -f "$HOME/.xdisplay" ] then DISPLAY=`cat $HOME/.xdisplay` rm -f $HOME/.xdisplay else DISPLAY="unknown:0" fi echo "$DISPLAY" In other words, if there's a .xdisplay file, use it to set DISPLAY. Note that .xdisplay is removed after it is used to avoid the possibility of rlogins clashing (it's better to have no DISPLAY than to have it be wrong). This solution has stood me well over the last few months. It's not perfect, especially since the way we have our network setup, half the machines I can login to can't find my home directory, but until there exists an rlogin-type function that can send across required variables, this should do fine. -- David Elliott dce@Solbourne.COM ...!{uunet,boulder,nbires,sun}!stan!dce "We don't do this because we love you or like you...we don't even know you!"
rlk@THINK.COM (Robert L. Krawitz) (09/07/89)
Passing DISPLAY across an rlogin isn't very hard; it simply requires overloading TERM. I use this script (which I call xdsp) to pass it across: #!/bin/sh TERM=xtu.$XDISPLAY export TERM exec rsh $* The following code in my .login picks it up: if (($TERM =~ xt?.*) || ($TERM =~ xt.*)) then setenv DISPLAY `echo $TERM | sed 's/xt[^.]*\.//'` set term = xterm setenv TERM xterm endif Under X10 I didn't need the sed; I could do everything with the shell. Under X11 I need the sed to handle the foo:0.0 syntax. ames >>>>>>>>> | Robert Krawitz <rlk@think.com> 245 First St. bloom-beacon > |think!rlk Cambridge, MA 02142 harvard >>>>>> . Thinking Machines Corp. (617)876-1111