cmdtool wont run under xdm on X terminal under SunOS 4.1

[Leonard Sitongia]

I've been using an NCD X-19 terminal with xdm from MIT X11R4 displaying
cmdtool from OpenWindows 2.0 served from a Sun-4/280 running SunOS 4.0.3 for 
some time.  It is simply exec'd from the .openwin-menu.

After I upgraded the Sun to SunOS 4.1, I have been unable to run the
cmdtool on the Sun to display directly on the X terminal.  If I exec a
cmdtool which rlogins to the same Sun (in other words the same cmdtool
which fails but in this case does a rlogin to the same system that the 
cmdtool is running on), it suceeds (using two ttyp?'s, though).

The failing cmdtool appears normal, in that it opens ok, and echos input,
but will not execute it.

In any case, when the cmdtool is started up, the xdm-errors reports:

ttysw-TIOCSPGRP: Interrupted system call

The only discernible difference is from tracing the two cmdtools.

In the case of the cmdtool which is rlogin'd, here is how it reads (I typed
in the letter "a"):

select (256, 0xf7fff5f0, 0xf7fff5d0, 0xf7fff5b0, 0xf7746894) = 0
gettimeofday (0x197d4, 0) = 0
write (3, "".., 168) = 168
ioctl (3, 0x4004667f, 0xf7fff2dc) = 0
gettimeofday (0xf7fff4b0, 0) = 0
setitimer (0, 0xf7fff420, 0) = 0
select (256, 0xf7fff5f0, 0xf7fff5d0, 0xf7fff5b0, 0) = 1
ioctl (3, 0x4004667f, 0xf7ffef4c) = 0
read (3, "".., 32) = 32
ioctl (3, 0x4004667f, 0xf7ffefe4) = 0
write (3, "".., 92) = 92
ioctl (3, 0x4004667f, 0xf7fff2dc) = 0
select (256, 0xf7fff5f0, 0xf7fff5d0, 0xf7fff5b0, 0) = 1
write (4, "a", 1) = 1
ioctl (3, 0x4004667f, 0xf7fff2dc) = 0
select (256, 0xf7fff5f0, 0xf7fff5d0, 0xf7fff5b0, 0) = 2
readv (4, 0xf774bd70, 2) = 2
gettimeofday (0xa9a0, 0) = 0
ioctl (3, 0x4004667f, 0xf7ffef4c) = 0
read (3, "".., 32) = 32
ioctl (3, 0x4004667f, 0xf7ffefe4) = 0
write (3, "".., 76) = 76
ioctl (3, 0x4004667f, 0xf7fff2dc) = 0
gettimeofday (0xf7fff4b0, 0) = 0
setitimer (0, 0xf7fff420, 0) = 0
select (256, 0xf7fff5f0, 0xf7fff5d0, 0xf7fff5b0, 0xf7746894) =

But the cmdtool which is simply exec'd is doing this (again, I typed 
in "a"):

select (256, 0xf7fff5f8, 0xf7fff5d8, 0xf7fff5b8, 0) = 1
ioctl (3, 0x4004667f, 0xf7ffef54) = 0
read (3, "".., 32) = 32
write (3, "".., 96) = 96
read (3, 0xf7ffdba4, 32) = -1 EWOULDBLOCK (Operation would block)
select (4, 0xf7ffda70, 0, 0, 0) = 1
read (3, "".., 32) = 32
read (3, "".., 28) = 28
read (3, "".., 168) = 168
read (3, "".., 2688) = 1820
read (3, "".., 868) = 868
ioctl (3, 0x4004667f, 0xf7ffefec) = 0
write (3, "".., 188) = 188
ioctl (3, 0x4004667f, 0xf7fff2e4) = 0
read (3, "".., 32) = 32
ioctl (3, 0x4004667f, 0xf7fff1fc) = 0
ioctl (3, 0x4004667f, 0xf7fff2e4) = 0
select (256, 0xf7fff5f8, 0xf7fff5d8, 0xf7fff5b8, 0) =

Can someone give me some insight into what is going wrong?

Thanks.
--
-Leonard E. Sitongia           sitongia at ncar.ucar.edu
System Manager                 (303) 497-1509
High Altitude Observatory      P.O. Box 3000 Boulder CO  80307