🚀 go-pugleaf

Index:	ksh/sh/name.c

Description:
	When using a non-default input field separator (such as ':'),
	trailing empty data fields cause ksh to underflow an input
	stack, and thus fail to correctly null-terminate the string
	before assigning it to the variable being read.

	This bug is present in both ksh (Version 02/21/85) and ksh-i
	(Version 06/03/86a) as distributed by the AT&T toolchest.

Repeat-By:
	Execute this shell file:

IFS=:$IFS
while read f1 f2 f3
do	echo f1=\""$f1"\" f2=\""$f2"\" f3=\""$f3"\"
done <<E-O-F
rec1.f1:rec1.f2:rec1.f3
rec2.f1:rec2.f2::
rec3.f1:rec3.f2::
E-O-F

# correct behavior:
#
#	$ sh g
#	f1="rec1.f1" f2="rec1.f2" f3="rec1.f3"
#	f1="rec2.f1" f2="rec2.f2" f3=":"
#	f1="rec3.f1" f2="rec3.f2" f3=":"
#	$
#
# incorrect behavior (note field 3):
#
#	$ ENV= ksh g
#	f1="rec1.f1" f2="rec1.f2" f3="rec1.f3"
#	f1="rec2.f1" f2="rec2.f2" f3=":ec2.f2"
#	f1="rec3.f1" f2="rec3.f2" f3=":ec3.f2"
#	$

Fix:
	In readvar() in name.c, where the top of the stack is being
	decremented past any trailing separators, make sure it doesn't
	go past the bottom of the stack.