SVR4 /bin/sh BUG Summary

[Rick Richardson]

I recently posted the enclosed script which demonstrates a
bug in SVR4's Bourne shell.  With the help of the net,
it appears that the bug is not restricted to just one
architecture.  Failure has been reported on:

	AT&T SVR4 on i386
	HCI SVR4 on i386
	Commodore SVR4 on Amiga
	SVR4 on i860

-Rick

#
#	Demonstrates bug in SVR4 /bin/sh
#	Works OK with /bin/sh on SVR3 and XENIX
#	Works OK with /bin/ksh on SVR4
#
#	Should output the first line of /etc/passwd four times
#	Only does it three times on SVR4 and then hangs
#
#	Seems to be related to changing fd0 in a function
#
read_by_func() {
	exec 3<&0 0<$1
	read x
	echo $x
	exec 0<&3 3<&-
}

exec 3<&0 0</etc/passwd
read x
echo $x
exec 0<&3 3<&-

exec 3<&0 0</etc/passwd
read x
echo $x
exec 0<&3 3<&-

read_by_func /etc/passwd

# Gets stuck here with /bin/sh...
read_by_func /etc/passwd
-- 
Rick Richardson		Email: rick at digibd.com
Senior MTS		Fax: (612) 943-0803
DigiBoard, Inc.		Tel: (612) 943-5383