Re: Possible solution for the alsa-oss fopen problem.

[James Courtier-Dutton <James@superbug.demon.co.uk>]

Florian Schmidt wrote:
> On Wed, 09 Jun 2004 12:10:45 +0100
> James Courtier-Dutton <James@superbug.demon.co.uk> wrote:
> 
> 
>>I have found out that the artsdsp /dev/oss redirector supports fopen and 
>>friends.
>>I looked at the artsdsp, (find it inside arts-1.2.2.tar.bz2)
>>It uses a function called fopencookie()
>>
>>Extract from /arts-1.2.2/artsc/stdioemu.c below.
>>
>>Would this be useable in the alsa-oss redirector?
> 
> 
> This fopencookie seems to be a libc thing to implement custom streams.. See
> 
> http://wwwwbs.cs.tu-berlin.de/user-taipan/kraxel/gnuinfo/libc/Streams_and_Cookies.html
> 
> Might be exctly the thing which is needed to intercept fopen() and friends AND handle the intercepted calls gracefully..
> 
> I have a question though: If this works for alsa-oss, then the libc problem with the internal symbols of open() and friends is solved. But i wonder if there are any other libs which are as "evil" in this regard as libc is. The basic problem persists: If a lib uses internal symbols for open() and friends and an app uses that lib to access /dev/dsp, etc., then we're screwed again..
> 
> On the other hand: How many libs besides libc do stuff like this? And how many apps use such a lib? I would guess: very very few.. If this is the case, i suppose it will work well (tm)
> 
> Florian Schmidt
> 

Does anyone have a small test app that uses fopen and friends, so that I 
could test them if I add fopencookie() to aoss.

Hopefully, the test app should use the fopen and friends calls in the 
same way that know "problem" apps use.

If there is not a test app out there, can someone please tell me more 
details about the problem, so that I could build a test app myself.

I need to know which fcalls lead to a failure, so that if I get those 
fcalls working, these "problem" apps will be guaranteed to work.

Cheers
James



-------------------------------------------------------
This SF.Net email is sponsored by: GNOME Foundation
Hackers Unite!  GUADEC: The world's #1 Open Source Desktop Event.
GNOME Users and Developers European Conference, 28-30th June in Norway
http://2004/guadec.org