On Thu, Jan 24, 2013 at 6:56 PM, Carlo E. Prelz <[email protected]> wrote:
> The biggest reason why your process does not die is most probably
> because you use system (which starts a shell). The signal reaches the
> shell but not gdb.
I don't think there is a signal at all because system just blocks
until the process dies and the timeout exception is raised *after* the
process has terminated and control comes back into the Ruby
interpreter. Proof:
Test script:
$ cat k.sh
#!/usr/bin/bash
echo "PID $$"
for i in {0..30}; do
trap "echo signal $i" $i
done
read -p ENTER # block
Demo to show signal output via pressing Ctrl-C:
$ ./k.sh
PID 2296
ENTERsignal 2
signal 2
signal 2
signal 2
signal 0
Now with Timeout:
$ time ruby -r timeout -e 'Timeout.timeout(2) { system "./k.sh" }'
PID 3552
ENTER
signal 0
-e:1:in `system': execution expired (Timeout::Error)
from -e:1:in `block in <main>'
from -e:1:in `<main>'
real 0m18.096s
user 0m0.046s
sys 0m0.201s
As you can see from real time I waited much longer than the timeout of
2 seconds before I pressed enter.
> So, instead of system, you should use Process::spawn. But even then,
> read carefully the doc: if you pass a command line (like in your
> example), you will still have a shell process in the middle. To avoid
> that, you must pass the parts of the command in an array. Every time I
> do this, I have to spend a decent amount of time finding how to
> correctly split the command.
That's generally good advice but I believe in this case not important
for the issue (see above).
> Anyway, you may try with something like:
>
> pid=Process::spawn(array)
>
> begin
> Timeout::timeout(5) do
> Process::waitpid(pid)
> end
> rescue Timeout::Error
> Process::kill(pid,'KILL')
> Process::waitpid(pid)
> end
That looks like a good solution.
Kind regards
robert
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