How do I solve this issue with gethostbyname_r and DBI or DBD::MySQL on FreeBSD?

Question

I have some old perl code which recently stopped working on a FreeBSD box. The code which fails looks (in simplest form) like this:

#!/usr/local/bin/perl -w

use strict;
use DBI;

my $datasource = "DBI:mysql:dbname:hostname.domain.com";
my $user = "username";
my $pass = "password";

DBI->connect($datasource, $user, $pass);

This fails with the following error:

/libexec/ld-elf.so.1: /usr/local/lib/mysql/libmysqlclient.so.15: Undefined symbol "gethostbyname_r"

If I change the datasource to reference "localhost" the code succeeds.

I've reinstalled mysql-client, DBI, and DBD-mysql from ports; no effect.

Other applications on this server (PHP, command line tools) are able to access mysql databases by hostname without trouble.

Suggestions for how to resolve this?

EDITED TO ADD: I notice that my box has both libmysqlclient.so.15 and libmysqlclient_r.so.15. Could the problem be that DBD::mysql is trying to use libmysqlclient when it should be using libmysqlclient_r? And if so, how to resolve?

Answer 1

A shot in the dark:

gethostbyname**_r** indicates that Perl uses the "reentrant" (also called threaded/multi-threaded) version of the resolver code. Seems something is wrong with that.

When compiling the dependencies from the ports tree you often can switch multi-threadedness on or off. You can change you previous choice with make config from each ports application directory.

If you installed binary packages probably there is a version mismatch somewhere in there.

Answer 2

'gethostbyname_r' is a GNU extension, and isn't part of the POSIX standard. Nevertheless, on my Freebsd 7 box, my libc includes it:

nm /usr/lib/libc.a | grep gethostbyname_r
00000eb0 T gethostbyname_r

Does your libc contains this symbol?

Answer 3

Your version of libmysqlclient is out of date for your operating system version. Since it's in /usr/local, I assume it's compiled from source rather than installed. You can probably fix it by recompiling, but you might want to see if there is a supported version of mysql that can be installed through your OSes package manager.

Answer 4

Try re-installing DBD-mysql from ports after temporarily moving /usr/local/lib/mysql/libmysqlclient.so.15 and /usr/local/lib/mysql/libmysqlclient.a out of the way (rename it or something). This might force DBD-mysql to link with the libmysqlclient_r.

Answer 5

As a workaround, try adding hostname.domain.com to /etc/hosts, or explicitly looking up the IP address in your Perl code and using that instead.

Answer 6

Did you ever get this issue resolved? I have re-installed mysql and the perl libraries.. No dice. :(

Answer 7

# ldd libmysqlclient.so.15
libmysqlclient.so.15:
        libcrypt.so.3 => /lib/libcrypt.so.3 (0x281bf000)
        libm.so.4 => /lib/libm.so.4 (0x281d7000)
        libz.so.3 => /lib/libz.so.3 (0x281ed000)

FreeBSD 6.4-p3, mysql-client installed from ports, reinstall not help with problem ;(

no libc in ldd output ;(

but mysql compiled correctly:

# ldd mysql
mysql:
        libreadline.so.6 => /lib/libreadline.so.6 (0x28089000)
        libncursesw.so.6 => /lib/libncursesw.so.6 (0x280b9000)
        libmysqlclient.so.15 => /usr/local/lib/mysql/libmysqlclient.so.15 (0x28102000)
        libcrypt.so.3 => /lib/libcrypt.so.3 (0x2815c000)
        libz.so.3 => /lib/libz.so.3 (0x28174000)
        libstdc++.so.5 => /usr/lib/libstdc++.so.5 (0x28185000)
        libm.so.4 => /lib/libm.so.4 (0x28250000)
        libc.so.6 => /lib/libc.so.6 (0x28266000)
        libncurses.so.6 => /lib/libncurses.so.6 (0x2834d000)