From: Tim Uckun <timuckun@...>
Date: 2010-10-04T10:24:57+09:00
Subject: Re: having problems with open4 and stuck forked processes

On Sat, Sep 25, 2010 at 9:05 PM, Robert Klemme
<shortcutter@googlemail.com> wrote:
> On 25.09.2010 00:25, Tim Uckun wrote:
>>>
>>> It would be safer to use select() on the data coming from the child to
>>> wait for the process to terminate (when you read end-of-file)
>>
>> But what if the process hangs?
>>
>> Wouldn't I need to use timeout to check for that anyway?
>
> Select can be called with a timeout which guarantees that the call returns
> in time regardless whether there is any data available.
>


Hey guys I want to revist this issue because I can't seem to find any
documentation on how to do this.

What I want to do seem simple enough. I want to shell out to a process
which sometimes gets stuck. It won't return at all. It just sits there
taking up 100% of the CPU (one of the cores anyway).  I just want to
make sure that if the process does not end in a reasonable amount of
time I want to kill it.

So far I have tried wrapping it in a timeout block but that doesn't
always trigger for some reason. I have plenty of error handling and
have an ensure block which says to kill the process if it exists but
nothing I do seems to work. Sooner or later I get a stuck process that
hangs around forever till I kill it by hand.

Surely there is a simple way to do this.

Here is the code I have so far.

http://gist.github.com/609119