Re: glibc and Unix98 PTY's

[Zlatko Calusic <Zlatko.Calusic@CARNet.hr>]

Andreas Jaeger <aj@arthur.rhein-neckar.de> writes:

> >>>>> Zlatko Calusic writes:
> 
>  > Ulrich Drepper <drepper@cygnus.com> writes:
> >> Zlatko Calusic <Zlatko.Calusic@CARNet.hr> writes:
> >> 
> >> > Now, the question *is*, can I use glibc 2.0.95 safely?
> >> 
> >> Many people run 2.0.9x libcs as the main libc (myself included) and
> >> have no problems.
> 
>  > Thanks. I was only wondering are there some hidden gotchas.
> 
> No - you just should be careful and have a backup handy.;-)

As always. :)

Even though, messing around with libc make some additional problems,
which I'm aware of, but that doesn't mean I won't get in trouble. :)

> 
> I'm appending a message I've written originally for 2.0.93 and which
> explains some caveats.  You also have to recompile your c++-library
> when upgrading from 2.0.7 to 2.0.95 but egcs has problems due to some
> changes in glibc 2.0.95.  Solutions have been suggested, e.g. on the
> egcs-bugs mailing list.
> 
> Andreas
> 
> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> Upgrading from glibc 2.0.7 to glibc 2.1 shouldn't be a big problem.
> Currently there are still some small problems - and therefore glibc
> 2.1 is still not released.  In this document, I'd like to point out
> some points you should be aware of when upgrading.
> 
> - Besides reading this file you should check the FAQ.  The FAQ
>   gives also hints about some general problems.
> 
> - This version of glibc is a _test_ release of glibc 2.1.  We (glibc
>   developers) tested it and it did work in our environment.  We don't
>   consider it of release quality and therefore encourage users to test
>   it and tell us about problems.  Problems should be reported direclty
>   to the glibc maintainer Ulrich Drepper <drepper@cygnus.com>.

I have some bug reports, even on 2.0.7 version. Should I really send
them directly to Ulrich. Is linux-gcc@vger maybe a better place?

> 
> - The current version contains some patches to make the build process
>   faster.  A lot of people complained that it takes too long to
>   compile glibc and Zack finally managed to make some real
>   improvements[1].  Sadly this broke one special case: Building in the
>   source directory.  We've always advocated to build glibc in an extra
>   build directory:
> >The `best' way to build glibc is to use an extra directory, e.g.:
> >tar xzf libc-970921.tar.gz
> >mkdir build-glibc
> >cd build-glibc
> >../libc-970921/configure ...
>   This is how we build glibc and therefore should always work.  I'd
>   advise everybody to use a build directory to build glibc -
>   independent of the version.

Huh, OK. This one I wouldn't know without you.

> 
> - Good sense dictates that you should only work temporarily as root.
>   Especially for running make or make check you don't need root
>   privilegs.  glibc 2.0.93 contained one testcase (io/ftwtest-sh)
>   which fails if you run `make check' as root.  Thanks to the reports
>   we've got, this test is now only run for non-root users.
> 
> - When upgrading glibc you should always have a backup of libc lying
>   around so that you easily can call programs if the update fails:
> 
> LD_LIBRARY=/libc-backup /libc-backup/ld-linux.so.2 /bin/sh

You mean, LD_LIBRARY_PATH?

How about putting new libc in the same directory (/lib) and then using 
LD_PRELOAD=/lib/libc.so.needed_ver some_executable?

> 
> - There're still some problems when upgrading from glibc 2.0.6/7 to
>   glibc 2.1 test releases.  IMHO the best way is to install everything
>   in a temporary directory and then copy it in single user mode:
> 
> make install install_root=/temporary-dir
> (cd /temporary-dir ; tar -clf - etc lib usr) | (cd / ; tar -xpf -)
> 
>   The problem is that during install some atomar operation are needed
>   but at the moment atomicity isn't guaranteed.:-(

Scary stuff... brrr :)

I prefer "cp -a" for thigs like this (much shorter and less prone to
mistakes than multiple tars).

Later,
-- 
Posted by Zlatko Calusic           E-mail: <Zlatko.Calusic@CARNet.hr>
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	 The 11th COMMANDMENT - Thou shalt not be a smartass!