Re: Q's about IBM TSM (was Re: HEADSUP: ibcs2 and svr4 comp at headed for history)

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On Wed, 30 Jun 2004 14:15, Thyer, Matthew wrote:
> Ideally this would need some kernel support to handle updating of the file
> whenever file systems are manually mounted and unmounted.  Remember that
> Linux's etc/mtab file is to record what is currently mounted.  A simple
> translation of FreeBSD's /etc/fstab at module load time or system boot time
> is not really adequate.

Ahh I see..
I guess it would be not significantly more complicated to ask the kernel what 
is mounted and gin up a fake mtab to feed in via LD_PRELOAD.

ie I don't think any magic kernel support would be needed (although that idea 
does have some appeal as then you wouldn't need LD_PRELOAD magic and it would 
work on static binaries).

> -----Original Message-----
> From: owner-freebsd-current_at_freebsd.org
> [mailto:owner-freebsd-current_at_freebsd.org]On Behalf Of Daniel O'Connor
> Sent: Wednesday, 30 June 2004 12:11 PM
> To: freebsd-current_at_freebsd.org
> Cc: Carl Makin; Paul Mather; Paul Seniura
> Subject: Re: Q's about IBM TSM (was Re: HEADSUP: ibcs2 and svr4 compat
> headed for history)
>
> On Wed, 30 Jun 2004 01:11, Paul Mather wrote:
> > I'm using the Linux 5.1.5.15 TSM client on a FreeBSD 5.2.1-RELEASE-p8
> > system.  (See previous message in this thread.)  It was a bit finicky to
> > get going.  I found I had better luck using emulators/linux_base-8 than
> > emulators/linux_base, though I did get it running under both.  One
> > hurdle for most people is that the client aborts with an out of memory
> > error during file activities.  I discovered that this is caused by
> > having an empty or missing /compat/linux/etc/mtab file.  Creating a
> > proper mtab file solves these problems.  One way to do this is via
> > something like the following:
> >
> > 	sed 's/ufs/ext2/' < /etc/fstab > /compat/linux/etc/mtab
> >
> > That way, the Linux TSM "sees" your UFS partitions and will
> > backup/restore to them.
>
> I wonder if it could work with an LD_PRELOAD or some other linker
> trickery..
>
> ie replace open()/read()/write() with something that looks for /etc/mtab
> and instead opens /etc/fstab and translates it on the fly..
>
> I don't use TSM though so I couldn't test it :)
>
> (BTW linux_devtools can be used to make something like this, I wrote one
> for the TeamSpeak port to hide an unimplemented sound ioctl)

- -- 
Daniel O'Connor software and network engineer
for Genesis Software - http://www.gsoft.com.au
"The nice thing about standards is that there
are so many of them to choose from."
  -- Andrew Tanenbaum
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