The problem has nothing to do with reaching the end of the file. As you can see, you can keep reading from a terminal after reaching the end of the file.

>perl -e"for my $x (1..2) { print qq{$x: $_} while <STDIN>; }"
a
1: a
b
1: b
c
1: c
^Z
d
2: d
e
2: e
f
2: f
^Z
[download]

The problem is much simpler. If STDIN was redirected away from the console, then it can't be used to read from the console. The solutions provided are alternate means of accessing the console.