Re: Dissociating process from bin's filesystem

Eric W. Biederman (ebiederm@xmission.com)
27 Apr 2002 13:03:11 -0600


Padraig Brady <padraig@antefacto.com> writes:

> I'm think this is not possible at the moment.
>
> The file of the executing process is in use as the backing store for
> one or more live virtual memory areas, so changing it could
> corrupt the processes using those areas. Hence you can't umount.
>
> Now the Mach kernel has a MAP_COPY flag to the mmap system call
> which would do what you want, but this is mucho complex/messy,
> so don't hold your breath for a linux implementation.
>
> A related note on shared libraries is you don't get the
> "text file busy" message if you update them while they're in use,
> like you do for executable files. The reason is MAP_DENYWRITE
> is ignored for security reasons. I think Eric Biederman has
> a workaround though?

I played with it but could find nothing better than.
chmod a-w file
And it wasn't terribly important personally so I dropped it.

Eric

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