Date: Sun, 2 Jan 2000 22:44:44 -0800 (PST) From: Doug White <dwhite@resnet.uoregon.edu> To: Marcel Moolenaar <marcel@scc.nl> Cc: current@freebsd.org Subject: Re: SUBMIT: compat.linux.pathmunge Message-ID: <Pine.BSF.4.21.0001022236430.51360-100000@resnet.uoregon.edu> In-Reply-To: <386FA009.15B46B3F@scc.nl>
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I'm bringing this back up to -current to kick around some more. We may want to move it to -emulators. On Sun, 2 Jan 2000, Marcel Moolenaar wrote: > > This isn't intended as a 'final solution' :-) The problem is *very* > > difficult since you're asking the syscall to intuit what the user/program > > intends to do with the file. > Hmmm.. What we want is a way to tell the Linuxulator on a process/binary > level whether we want /compat/linux overlaying or not. Indeed, backup > clients will pick up /compat/linux as an ordinary directory without > overlaying and that is exactly what we want. In most cases we do want > the overlaying. Having process/binary granularity would be more useful, but is hard to implement in an inobrusive way, as we're discovering below. :) Binary granulatirty could be an issue for shells. > > If you could tag dynamic loader open()s you could have a selective > > translator for just that, but when it's hunting for /etc/host.conf, which > > one do you give it? Is it a call from resolv+ looking for it's > > configuration, or a backup client putting it on tape? > > What about brandelf? When a static ELF binary is branded as `Linux', we > have overlaying; when it's branded as 'LinuxBSD' (or what's in a name) > it's a Linux binary that don't want/need overlaying. Dynamic ELF > binaries are more tricky, but can make to work by setting > LD_LIBRARY_PATH in a wrapper. Yuck. brandelf is an agreed-on standard (or is supposed to be) and it wouldn't be appropriate to abuse it. I'd be more apt to run the target app in a wrapper that makes a 'shut off translation for this pid' type syscall then execve()s the app. Kinda like nohup. > > I don't have any ideas at this point. I'd be willing to add some features > > to this patch (i.e. specify arbitrary root) but I don't want to sit on it > > until linuxmode grows a psychic user mind reader. :) > > :-) It isn't as easy as it looks, eh? Doug White | FreeBSD: The Power to Serve dwhite@resnet.uoregon.edu | www.FreeBSD.org To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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