Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!csd4.milw.wisc.edu!leah!itsgw!steinmetz!ge-dab!tardis!barry
From: barry@tardis.DAB.GE.COM (Barry Fishman)
Newsgroups: comp.windows.x
Subject: Re: A "fix" for wall.
Summary: Patch to remove host field from utmp entry for local xterms
Keywords: X11 xterm wall
Message-ID: <1937@ge-dab.GE.COM>
Date: 2 Apr 89 02:22:33 GMT
References: <8903300011.AA29356@Larry.McRCIM.McGill.EDU>
Sender: news@ge-dab.GE.COM
Reply-To: barry@tardis.dab.ge.com (Barry Fishman)
Organization: GE Simulation & Control Systems Dept., Daytona Beach, FL
Lines: 53

Phil Dykstra in <8903290045.aa18749@SPARK.BRL.MIL> noted:
> If you look
> in Sun's /usr/include/utmp.h you find a define for nonuser() used to
> determine if a pty entry in utmp corresponded to a "real" user or not
> (i.e. someone who should get a wall message).  If the host field is
> non-zero it assumes an rlogin and writes to that window.  SunView
> doesn't write in the host field for local windows so this works fine
> there.  X puts the display name in that field, and thus get a copy
> of the message.
   [Followed by a contributed nonuser() macro]

Creating a utmp entry with a blank host field seems to work well in our
mixed computer environment.  Sun console windows still get console messages
from wall anyway.  However, I did not find a reference to nonuser() in
xterm/main.c so I assume a direct patch to main.c is needed.

We have been using the following patch based on a previously posted
patch to X10R4 (unfortunately I can not find the original) since X11R1.
This change can not handle the recent use of ":0.0" style display
references or hosts with names beginning with "unix", but I would rather
present something that I have been using without problems for a long time,
than something put together just before posting.

The '(strncmp("unix" ...) != 0)' should probably be replaced with Phil's
'(!nonuser())' to give a cleaner solution.

*** clients/xterm/main.c-	Sat Jan  7 13:37:16 1989
--- clients/xterm/main.c	Fri Jan 13 21:11:20 1989
***************
*** 1735,1743 ****
  					       sizeof(utmp.ut_line));
  				(void) strncpy(utmp.ut_name, pw->pw_name,
  					       sizeof(utmp.ut_name));
! 				(void) strncpy(utmp.ut_host, 
  					       XDisplayString (screen->display),
  					       sizeof(utmp.ut_host));
  				time(&utmp.ut_time);
  				lseek(i, (long)(tslot * sizeof(struct utmp)), 0);
  				write(i, (char *)&utmp, sizeof(struct utmp));
--- 1739,1752 ----
  					       sizeof(utmp.ut_line));
  				(void) strncpy(utmp.ut_name, pw->pw_name,
  					       sizeof(utmp.ut_name));
! 				if (strncmp("unix", 
! 				   XDisplayString (screen->display), 4) != 0)
! 				{
! 				   (void) strncpy(utmp.ut_host, 
  					       XDisplayString (screen->display),
  					       sizeof(utmp.ut_host));
+ 				}
  				time(&utmp.ut_time);
  				lseek(i, (long)(tslot * sizeof(struct utmp)), 0);
  				write(i, (char *)&utmp, sizeof(struct utmp));