Re: send_sigqueue problem..

[Fawad Lateef <fawadlateef@gmail.com>]

On 11/3/05, ppunnam@kent.edu <ppunnam@kent.edu> wrote:
>
> i am trying to use the linux signaling to signal a user process from
> the kernel..
> i require a reliable(without any signal loss) and fast signaling
> mechanism.
> i tried to use the send_sigqueue to send the signals...here what i did
>
> 1) creted the sigqueue structure using the sigqueue_alloc()..
> 2) called the send_sigqueue() function...
> it worked fine for some time(around 1000 sig) but after that
> sigqueue_alloc failing..may be becuse of not enough memory  available
> to allocate sigqueue..

Its obvious that if you allocate some-thing (like through
sigqueue_alloc) then you have to free that too (like through
sigqueue_free)

> i got few question about this..
>
> 1) does sigqueue structure need to be removed explisitly or it will be
> autometically cleared after the signal delivery (i did't used the
> sigqueue_free() becuse i dont know when the signal is deliverd).

yes, you have to remove the structure explicitly as you allocated it
by your-self ! And I think you can call sigqueue_free just after
calling send_sigqueue because the singals are delivered to the process
with the wake_up call and then you can remove your sigqueue structure
(I might be wrong as I am saying this by just going through the
send_sigqueue function, CMIIW)


> 2)there is any another way i can implement such a signaling mechanism.
>

I saw one simple way in signal.c file. send_sig function which sends
signal by-itself (means allocate sigqueue internally) see
http://lxr.linux.no/source/kernel/signal.c#L1249



--
Fawad Lateef