Re: [owl-users] CentOS packages

From: Solar Designer <solar_at_private>
Date: Thu, 1 Oct 2009 17:44:42 +0400
On Wed, Sep 30, 2009 at 11:00:13PM +0400, croco_at_private wrote:
> I tried all this, and finally installed all the stuff successfully.  After
> that (and after configuring the Apache conf files) I got the following:
> 
> varan101!root:~# apachectl start
> *** glibc detected *** free(): invalid pointer: 0x800c0ae8 ***
> /usr/sbin/apachectl: line 102:  5692 Aborted                 $HTTPD
> $OPTIONS -k $ARGV

Ouch.  This made me curious enough that I went ahead and installed the
packages myself.  While at it, I learned an even easier way to resolve
the dependencies.  With rpmdb-CentOS installed on Owl (and nothing else
installed yet), I get:

bash-3.1# rpm -Uvh httpd-2.0.52-41.ent.4.centos4.i386.rpm
error: Failed dependencies:
        /etc/mime.types is needed by httpd-2.0.52-41.ent.4.centos4
        apr >= 0.9.4-24.2 is needed by httpd-2.0.52-41.ent.4.centos4
        httpd-suexec is needed by httpd-2.0.52-41.ent.4.centos4
        libapr-0.so.0 is needed by httpd-2.0.52-41.ent.4.centos4
        libaprutil-0.so.0 is needed by httpd-2.0.52-41.ent.4.centos4
        libdb-4.2.so is needed by httpd-2.0.52-41.ent.4.centos4
        libexpat.so.0 is needed by httpd-2.0.52-41.ent.4.centos4
        libgssapi_krb5.so.2 is needed by httpd-2.0.52-41.ent.4.centos4
        libk5crypto.so.3 is needed by httpd-2.0.52-41.ent.4.centos4
        libkrb5.so.3 is needed by httpd-2.0.52-41.ent.4.centos4
        liblber-2.2.so.7 is needed by httpd-2.0.52-41.ent.4.centos4
        libldap-2.2.so.7 is needed by httpd-2.0.52-41.ent.4.centos4
    Suggested resolutions:
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/apr-0.9.4-24.9.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/apr-util-0.9.4-22.el4.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/db4-4.2.52-7.3.el4.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/expat-1.95.7-4.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/httpd-suexec-2.0.52-41.ent.4.centos4.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/krb5-libs-1.3.4-62.el4.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/mailcap-2.1.17-1.noarch.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/openldap-2.2.13-12.el4.i386.rpm

Notice the "Suggested resolutions" part, which did not appear without
rpmdb-CentOS.  Downloading and adding those packages to the line, I get:

rpm -Uvh httpd-2.0.52-41.ent.4.centos4.i386.rpm apr-0.9.4-24.9.i386.rpm apr-util-0.9.4-22.el4.i386.rpm expat-1.95.7-4.i386.rpm httpd-suexec-2.0.52-41.ent.4.centos4.i386.rpm krb5-libs-1.3.4-62.el4.i386.rpm mailcap-2.1.17-1.noarch.rpm openldap-2.2.13-12.el4.i386.rpm 

which prints:

error: Failed dependencies:
        libdb-4.2.so is needed by httpd-2.0.52-41.ent.4.centos4
        libdb-4.2.so is needed by apr-util-0.9.4-22.el4
        cyrus-sasl is needed by openldap-2.2.13-12.el4
        cyrus-sasl-md5 is needed by openldap-2.2.13-12.el4
        libsasl2.so.2 is needed by openldap-2.2.13-12.el4
    Suggested resolutions:
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/cyrus-sasl-2.1.19-14.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/cyrus-sasl-md5-2.1.19-14.i386.rpm
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/db4-4.2.52-7.3.el4.i386.rpm

So I download these three, and add cyrus-sasl and cyrus-sasl-md5 to the
line (not yet db4 because Owl-current already has newer db4, so it needs
special handling).  This reduces the "complaints" to just:

error: Failed dependencies:
        libdb-4.2.so is needed by httpd-2.0.52-41.ent.4.centos4
        libdb-4.2.so is needed by apr-util-0.9.4-22.el4
    Suggested resolutions:
        /home/buildcentos/CENTOS/en/4.0/i386/CentOS/RPMS/db4-4.2.52-7.3.el4.i386.rpm

Time to deal with db4.  I install it with:

bash-3.1# rpm -ivh --force db4-4.2.52-7.3.el4.i386.rpm 
warning: db4-4.2.52-7.3.el4.i386.rpm: V3 DSA signature: NOKEY, key ID 443e1821
Preparing...                ########################################### [100%]
   1:db4                    ########################################### [100%]

Please note that at this point we have two versions of db4 installed -
Owl-current's newer version and CentOS' older one.  This is not a
downgrade, just two versions of db4 at once.  That's one of the rare
cases/exceptions where rpm's "-i" option is desirable.

Also note that I did not bother installing the CentOS GnuPG key; if this
were not a test environment only, the key would better be installed.

Finally, with the older version of db4 in place, the rest installs:

bash-3.1# rpm -Uvh httpd-2.0.52-41.ent.4.centos4.i386.rpm apr-0.9.4-24.9.i386.rpm apr-util-0.9.4-22.el4.i386.rpm expat-1.95.7-4.i386.rpm httpd-suexec-2.0.52-41.ent.4.centos4.i386.rpm krb5-libs-1.3.4-62.el4.i386.rpm mailcap-2.1.17-1.noarch.rpm openldap-2.2.13-12.el4.i386.rpm cyrus-sasl-2.1.19-14.i386.rpm cyrus-sasl-md5-2.1.19-14.i386.rpm 
warning: httpd-2.0.52-41.ent.4.centos4.i386.rpm: V3 DSA signature: NOKEY, key ID 443e1821
Preparing...                ########################################### [100%]
   1:krb5-libs              ########################################### [ 10%]
   2:expat                  ########################################### [ 20%]
   3:apr                    ########################################### [ 30%]
   4:mailcap                ########################################### [ 40%]
   5:cyrus-sasl             ########################################### [ 50%]
   6:openldap               ########################################### [ 60%]
   7:apr-util               ########################################### [ 70%]
   8:httpd                  ########################################### [ 80%]
   9:httpd-suexec           ########################################### [ 90%]
  10:cyrus-sasl-md5         ########################################### [100%]

Now to reproduce "your" problem:

bash-3.1# service httpd start
Starting httpd: httpd: Could not determine the server's fully qualified domain name, using 127.0.0.1 for ServerName
*** glibc detected *** free(): invalid pointer: 0xb942c6d8 ***
/etc/rc.d/init.d/functions: line 34: 30087 Aborted                 start-stop-daemon $FLAGS --startas /bin/nice -- -n "$NICE" "$WHICH" $*

Oops.  Really nasty.  Here's a guess: they have a bug in the CentOS 4
package(s), likely also present in the RHEL4 packages, but they are not
running into it because their slightly older glibc (2.3.4'ish) does not
check for this kind of errors yet (vs. our 2.3.6'ish).  Let's disable
killing of the process ("1" means "Generate an error message, but do not
kill the program"):

bash-3.1# MALLOC_CHECK_=1 service httpd start

Lots of "*** glibc detected *** free(): invalid pointer" messages on
httpd startup, but it does start up now. :-)  Going to the server with a
web browser, I get an empty directory listing with:

Apache/2.0.52 (CentOS) Server at xxx.xxx.xxx.xxx Port 80

at the bottom.  So Apache seems to work despite of those errors.
Perhaps that's how it actually works on CentOS 4 and RHEL4 (I might
report this to Red Hat, although reporting it in this way is weird).

Now to stop it:

bash-3.1# service httpd stop
Stopping httpd: /etc/rc.d/init.d/functions: line 147: kill: d: invalid signal specification

Oops.  In /etc/rc.d/init.d/httpd, they have:

	killproc -d 10 $httpd

Editing the file to remove "-d 10" makes the above command work just
fine.  We'll need to consider adding support for "-d" into the function
on Owl, at least "dummy support" (ignore the option).

To summarize: it is not very hard to identify, download, and install all
of the needed packages, and even to get CentOS' httpd to work on Owl,
but it does require knowledge/skills (note: that's not knowledge of
specific Red Hat package names, with the only exception being rpmdb-*).
Perhaps even more importantly, I would feel uncomfortable running httpd
with now-known dynamic memory (de)allocation issues and with plenty of
libraries that are irrelevant for my intended use.  Thus, I'd use a
custom build of Apache, perhaps installing it under /opt/apache/VERSION
and pointing /opt/apache/current to there (this is Openwall's convention
for local builds/installs that can be moved between similar systems).

> As far as I understand, such a thing, happening to a well-tested stable
> package, should mean a shared libraries incompatibility.

Sort of, but not exactly.

> At this point I
> decided not to follow this way any further; fortunately all the things
> happened within a OpenVZ container so that I could just shut down the VPS
> and create another one from scratch.  It would be too complicated to
> reinstall the real machine, and it is tricky to restore the status quo
> after lots of packages were installed and some of them even downgraded the
> existing ones.

Why "downgraded"?  Please see my explanation regarding db4 above.  It's
not a downgrade.

I agree that this behavior of CentOS' httpd is a reason to abandon it.

> Errr... I continue to think it is a wastage of time to try making foreign
> packages work under Owl.

This might not be worth the time, but it is not exactly a waste of time.
Having the option to install certain "foreign" packages is of some use.
For example, when a client asks us to install Emacs on an Owl system
where they have an account, we simply do:

bash-3.1# rpm -Uvh emacs-*
warning: emacs-common-21.3-19.EL.4.i386.rpm: V3 DSA signature: NOKEY, key ID 443e1821
Preparing...                ########################################### [100%]
   1:emacs-common           ########################################### [ 50%]
   2:emacs-nox              ########################################### [100%]

(OK, need to have the GnuPG key when doing it for real, or better yet
pre-check the package files against a previously-checked copy.)

So emacs-nox from CentOS 4 just installs on Owl, with no dependencies at
all.  Then it just works (run "emacs-nox" as a user on the system).  We
find this quite useful.

> I should have spent this day compiling Apache
> from the sources instead -- I think it could give me better results.

Yes, but neither approach should be taking a day - more like an hour, at
least now that you're aware of rpmdb-CentOS.

> > Thank you for your testing, which happened to remind us of the db4
> > version issue.
> 
> I don't think this 'issue' worth the time you're going to spend fixing it.

You may be right.  We might end up mentioning it in Owl/doc/REDHAT,
along with the trivial workaround (above).

Anyhow, we have identified a few issues due to your testing, and we have
already improved the wiki content a little bit.  Thanks!  I wish others
provided this sort of feedback (and criticism) as well (and did so on
owl-users as well; we're in fact receiving more feedback in private).

Alexander

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Received on Thu Oct 01 2009 - 06:44:42 PDT

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