Re: [Dazuko-help] Problem with dazukofs.ign

[Lino Sanfilippo]

Ľuboš Matejíček wrote:
> Yesterday I played with dazukofs and work with dazukofs.ign surprised.
>
> For unix system is typical that, if any processes share filescriptor
> (don't depend how process get it) all copies of fd have the same behavior.
>
> For example if one process open a file and process forks, than parent
> and child share filedescriptor - there si no diffence whether any
> operation do parent or child. But - when process open file
> /dev/dazukofs.ign and forked, only parents events were excluded from
> scanning.
>   

Being ignored is not a property of a file (and thus its not inherited).
It is a part of dazukofs policy that the thread that opened the file
is automatically registered.  You could see it as a convenient method
for writing data ("ignore process XY") to a device (dazukofs).
You would not expect a fork() to trigger writing data to a an open device
automatically, would you?

> Next surprised gone, when I played with threads. Because I found, that
> if open file dazukofs.ign, this don't affects any other thread in the
> same process. I found, that all threads have to open this file.It is
> not very unix behaviour.
>   

Dazukofs ignores threads and not processes. Again its part of the
policy and has nothing to do with unix behaviour.
> Next thing what is not the best is need to seek after reading
> dazukofs.ctrl. It complicates writing  scanning  threads. I think that
> the most simple model, would be if every thread read dazukofs.ctrl and
> scaned the result without need to synchronize. But because of the lseek
> we need to synchronize threads.
>           Lubos
>   

Youre right, this is something that could be improved.
But until then: what about pread()?

Regards,
Lino Sanfilippo

Geschäftsführender Gesellschafter: Tjark Auerbach
Sitz der Gesellschaft: Tettnang
Handelsregister: Amtsgericht Ulm, HRB 630992
ALLGEMEINE GESCHÄFTSBEDINGUNGEN
Es gelten unsere Allgemeinen Geschäftsbedingungen
(AGB). Sie finden sie in der jeweils gültigen Fassung
im Internet unter http://www.avira.de/agb
***************************************************