Description of problem:
tracer performs a check to see if it can expect additional input from stdin, if so then it tries to read from stdin
https://github.com/FrostyX/tracer/blob/master/tracer/main.py#L42
However, this conditional also triggers if you run tracer via a non-tty ssh method. tracer then hangs on the blocking read until the session is killed.

Version-Release number of selected component (if applicable):
All versions. This part of the codebase has been intact for at least 7 years.

How reproducible:
100%

Steps to Reproduce:
1. Install tracer on a host
2. ssh root@<your host> tracer

Actual results:
The ssh command will continue to wait until killed (or timed out by other means)

Expected results:
tracer runs as normal (with a better mechanism of checking the stdin buffer)

Additional info:
os.isatty(0) also has the same issue