[uCsimm] RE: [UCLINUX] BIIIIG conceptual problem with ucLinux

From: Vadim Lebedev (vlebedev@aplio.fr)
Date: Thu Feb 03 2000 - 13:50:22 EST


Hi Fabien,

This problem will show up on all version of ucLinux....

However, thinking about it little bit more, it seems that the problem
is not so critical...

when a task A does 'vfork' under ucLinux, it remains blocked until
the child does 'exec'... So even if the achild access the parent's address
space this access is really not simultaneous with the parrent.
If the access is only limited to errno variable it is acctually no big deal
at
all, because the vfork will return success to the parent the parent will
simply
ignore the error code stored in the errno....

Of course the child task code should be really simple after vfork,
        exec, and _exit in case of failure

Still the idea to reserve C-Runtime specific area in the ucLinux task
structure
seems attractive to me.

Vadim

-----Original Message-----
From: fabien.klein@conexant.com [mailto:fabien.klein@conexant.com]
Sent: jeudi 3 février 2000 19:17
To: Vadim Lebedev
Subject: Re: [UCLINUX] BIIIIG conceptual problem with ucLinux

Salut Vadim

Est ce que c'est un probleme specifique a arm-uclinux ?
Ca voudrait dire que toutes les applications users (shells and co) seraient
inutilisables a l heure actuelle ?
J etais justement stuck avec ce probleme en essayant de lancer init qui fait
de
nombreuses combinaisons vfork -execxx...

As tu deja experimente les eventuels work-around (combinaison vfork-execv ou
la
2eme methode ??)

Fabien

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