Dear Maintainer,

I have noticed after misconfiguring a genmon plugin that if the started
application tries to read from /dev/tty (for instance, svn asking a password),
not only genmon freezes, but the whole session may block as well.

I have reproduced the problem with those steps:
1) Create a new user
2) Log in as this user, run startxfce4, use the default panel parameters
3) Create a shell script which does nothing (I used #!/bin/sh \n exit 0)
4) Add a generic monitor to the panel, configure it so it starts the shell
script
5) Log out
6) Add "cat /dev/tty" to the shell script
7) Run startxfce4 again

On my system, the background and the Xfce panels start to appear, but then
everything freezes (the mouse still moves and Ctrl-Alt-Fx still works, tough)

I think that in my case it also caused lightdm to abort the session start (i.e.
after entering the username/password and clicking Login, the screen goes blank
for some seconds and the prompt reappears), but I haven’t tried to reproduce
it with my testcase so it may be an unrelated problem.