Centos 7.1 – 32 bit program on 64 bit OS

32bit-64bitcentos7

I have successfully installed a piece of 32 bit software on a 64 bit VPS running CentOS 7.1. I had to install the 32 bit library before it would install but now when I try to launch it I am getting this error:

[root@001 bin]# bash ./nre
./nre: ./nre: cannot execute binary file

If I look up the file requirements I I get:

[root@001 bin]# file nre
nre: ELF 32-bit LSB executable, Intel 80386, version 1 (SYSV), statically linked (uses shared libs), stripped

All of my reading points to the error likely being a 32 binary issue but since I already have the library installed I am a little confused as to why I am receiving this error. How do I go about diagnosing if I am indeed missing a library and if I am, which one?

Alright, using the strings -a command I think I was able to produce a list of dependancies. Is there an easy way to determine what I am missing?

/lib/ld-linux.so.2
libnre.so
__gmon_start__
_Jv_RegisterClasses
_init
_ZN11NreLauncher11getInstanceEv
_fini
_ZN11NreLauncher3nreEPKciPPc
libdl.so.2
libstdc++.so.6
__gxx_personality_v0
libm.so.6
libgcc_s.so.1
libpthread.so.0
libc.so.6
_IO_stdin_used
umask
stderr
getuid
fwrite
geteuid
__libc_start_main
_edata
__bss_start
_end
CXXABI_1.3
GLIBC_2.0
PTRh
QVhp

Best Answer

It may be that you are trying to use Bash to execute a binary file.

Instead, try simply running the following:

./nre

1. Installation

Your MySQL installation could have come from different sources. It could be an rpm that came with the distribution or a Sun/Oracle rpm or it could have been built from sources.

 rpm -q --whatprovides $(which mysql)

should tell you the name of the package like

MySQL-client-...
mysql-5.0...
mysql-community-server-client
mysql-5.1...
no package provides /usr/bin/mysql.

On CentOS the first two options are most likely. MySQL-client-5.0 is a Sun/Oracle RPM and mysql-5.0 could have come from the distribution. Use rpm -q --info <package_name> to get extended information and verify that the Vendor: line confirms the hypothesis.

Here is a typical Vendor line:

Name        : MySQL-shared-community       Relocations: (not relocatable)
Version     : 5.0.96                       Vendor: Oracle and/or its affiliates

1.1 MySQL from Sun/Oracle RPMs

If your mysql installation comes from Sun/Oracle, go to MySQL Community server download page, select among Generally Available (GA) releases the one that has mysql 5.0 version and 32-bit architecture, choose MySQL-shared-community package, download and install it with rpm -i. This package provides exactly the /usr/lib/libmysqlclient.so.15 library.

1.2 mysql from CentOS

In CentOS5 libmysqlclient belongs to the mysql package.

yum install mysql.i386

should do the trick.

In CentOS6 it was moved to a separate mysql-libs package.

2. Testing

After installing the library, check if dynamic library dependencies are resolved correctly:

ldd <your_binary> | grep libmysqlclient

should return something like

libmysqlclient.so.15 => /usr/lib/mysql/libmysqlclient.so.15

If you want to know what provides a 32-bit version of a specific 64-bit library, you could use rpm -q --whatprovides /path/to/your/lib64/library to determine the name of the package. Then replace x86_64 with i686 in the name to get the name of the 32-bit counterpart. Use yum search to verify if the package is provided by the repositories you have subscribed to.

Windows – Reasons to Keep 32-bit Microsoft Windows Desktop OSes

32-bit can be slightly faster in certain use cases -- the smaller addresses means sightly more compact code, which means greater cache efficiency. In the benchmarks I've seen, that efficiency tends to be be overshadowed by 64-bit's greater computational efficiency in heavy-computation environments. But 32-bit does in fact occasionally win on some benchmarks. YMMV. The age of your software matters, as newer builds take advantage of 64-bit stuff that older builds do not.
More compact code means less disk space. Just go download the ISOs for your favorite OS in 64 and 32 -bit flavors to see the difference. It's not trivial. It's also quite a lot more once you uncompress the binaries. As pointed out by OrangeDog: Much of this space consumption comes from the fact that 64-bit OSes ship 32-bit libraries in addition to the 64-bit ones.
You still get better compatibility with legacy components and software with 32-bit. This is particularly visible in systems that dynamically compile on the host machine but pull in 3rd-party binary libraries at the same time. Microsoft's .NET framework is a great example of this: while the programs are theoretically architecture-independent, anytime you link to a native binary you tie to one arch or the other. Many developers don't even know this is happening, and ship production components that will fail to run on 64-bit systems without some tweaking to explicitly instruct .NET to run in 32-bit mode. Most people don't know how to do this.
As pointed out by Daniel B: Windows .NET development on 64-bit machines leaves you open to a frustrating inconsistency where under certain circumstances exceptions are masked by the OS.
Legacy hardware. You can't run a 32-bit driver on a 64-bit kernel.

None of this adds up to a show-stopper for most people. Still, you have to decide how these factors affect your environment.

Best Answer

Related Solutions

Linux – Install 32-bit MySQL client library on a 64-bit CentOS

1. Installation

1.1 MySQL from Sun/Oracle RPMs

1.2 mysql from CentOS

2. Testing

Windows – Reasons to Keep 32-bit Microsoft Windows Desktop OSes

Related Topic