Re: getting dpkg-shlibdeps to work on the Hurd
On Sat, May 18, 2002 at 08:51:11PM -0500, Adam Heath wrote:
> Not all filesystems have sane st_dev and st_inode numbers.
Mmmh, well they should, it's required by POSIX[1]. From looking at the code,
Linux 2.4 behaves a lot better on this than previous versions, and the Hurd
got it right forever (do I dare to add "of course"? No, I don't ;).
I don't know about BSD, though (or other operating systems).
It's a pity that st_dev is so underrated, it is very useful for these
things.
Maybe there is something more reliable but OS specific we can use?
The Hurd has an io_identity call you can use to match up two ports (think
filedescriptor if you are not familiar with ports) and see if they refer to
the same file[2]. If something similar exists in the Linux kernel, it might be
worth to go for st_* on systems where it is safe, fall back to the reliable
OS specific implementation if it exists, and otherwise fall back to realpath,
at the cost that it is really much slower than a simple stat (for the normal
operation, the bottleneck will probably be the database search, but for
things like */copyright I would estimate that realpath becomes noticably
slower.). Actually, it will be trivial to make tests when the code is there,
so we don't need to decide this now at all.
[1]
The draft 7 (which was the last draft before the latest version was
released) has in description of sys/stat.h:
"The st_ino and st_dev fields taken together uniquely identify the file
within the system."
[2] If you wonder if this isn't redundant, then it might interest you that
this call can be made on any I/O object, including a pipe or a socket, and
it will work reliably, while st_* will only work reliably on files.
> > > * Much more complex search algorithm.
> >
> > It's a bit more complex, but it should refactor nicely (eg, what you need in
> > (3) above should be possible to do with the current code, and then the
> > filter has to be added on top of it).
>
> So, now just have to con someone to write the patch. :)
I might have a crunch at the code (assuming dpkg-search isn't written
in python ;). I will have a look at the code and tell you how it goes.
Thanks,
Marcus
--
`Rhubarb is no Egyptian god.' Debian http://www.debian.org brinkmd@debian.org
Marcus Brinkmann GNU http://www.gnu.org marcus@gnu.org
Marcus.Brinkmann@ruhr-uni-bochum.de
http://www.marcus-brinkmann.de
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