Two fixes here:

Two fixes here:
1. If fgets fails, don't go into an infinite cpu-intensive loop.  Instead,
check to see if the terminal still exists, and sleep(1) otherwise.
2. When we check to see if the terminal still exists, make sure we're not
mislead by EINTR.  This could have been a security issue, but fortunately
the current implementation of tcgetattr doesn't EINTR.

PR: bin/60758
Approved by: rwatson (mentor)