Synology DSM6 - libc.so.6 - File format not recognized

Question

My final goal is to install Nagios on my Synology DiskStation DS1813+ with DSM 6.0.1-7393 Update 1. But I can't even begin compiling the package...

When I try to use gcc on my Synology DiskStation I always get the following error message:

$ gcc hello.c -o hello.o
/lib/libc.so.6: file not recognized: File format not recognized
collect2: ld returned 1 exit status

Here's my shell environment. I have tried it with different LD_LIBRARY_PATH settings, but even omitting it doesn't make a difference.

$ env
TERM=xterm-256color
SHELL=/bin/sh
SSH_CLIENT=192.168.2.110 51079 22
OLDPWD=/var/services/homes/egi
SSH_TTY=/dev/pts/7
LC_ALL=en_US.utf8
USER=egi
LD_LIBRARY_PATH=/opt/lib:
PAGER=more
MAIL=/var/mail/egi
PATH=/opt/sbin:/opt/bin:/sbin:/bin:/usr/sbin:/usr/bin
PWD=/var/services/homes/egi/exer
LANG=en_US.utf8
PS1=[\u@\h \W]$ 
SHLVL=1
HOME=/var/services/homes/egi
TERMINFO=/usr/share/terminfo
LOGNAME=shunyam
SSH_CONNECTION=xxx.xxx.xxx.xxx 51079 yyy.yyy.yyy.yyy 22
PGDATA=/var/services/pgsql
CC=gcc
_=/opt/bin/env

The compiler has been installed with ipkg and its specs look like this:

$ gcc --verbose
Using built-in specs.
Target: i686-linux-gnu
Configured with: ../gcc-4.2.1/configure --build=i386-pc-linux-gnu --host=i686-linux-gnu --target=i686-linux-gnu --prefix=/opt --disable-nls --disable-static --with-as=/home/slug/optware/syno-i686/toolchain/gcc-4.2.1-glibc-2.3.6/i686-linux-gnu/bin/i686-linux-gnu-as --with-ld=/home/slug/optware/syno-i686/toolchain/gcc-4.2.1-glibc-2.3.6/i686-linux-gnu/bin/i686-linux-gnu-ld --enable-languages=c,c++ --disable-multilib
Thread model: posix
gcc version 4.2.1

The library that causes the problem returns this information:

$ /lib/libc.so.6 
GNU C Library (crosstool-NG 1.20.0) stable release version 2.20-2014.11, by Roland McGrath et al.
Copyright (C) 2014 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.
There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A
PARTICULAR PURPOSE.
Compiled by GNU CC version 4.9.3 20150311 (prerelease).
Available extensions:
    crypt add-on version 2.1 by Michael Glad and others
    GNU Libidn by Simon Josefsson
    Native POSIX Threads Library by Ulrich Drepper et al
    BIND-8.2.3-T5B
libc ABIs: UNIQUE IFUNC
For bug reporting instructions, please see:
<http://www.gnu.org/software/libc/bugs.html>.

There is also a linker script at /opt/lib/libc.so:

$ cat /opt/lib/libc.so
/* GNU ld script
   Use the shared library, but some functions are only in
   the static library, so try that secondarily.  */
OUTPUT_FORMAT(elf32-i386)
GROUP ( /lib/libc.so.6 /opt/lib/libc_nonshared.a )

The library can't actually be broken, otherwise nothing would work at all.

Alongside with gcc all other required packages have also been installed with ipkg.

Weirdly enough I seem to be the only person with that issue as I have found no relevant posts on Google. Synology's support told me that they are not supporting installing command command line packages.

When I first installed gcc on this Diskstation about two years ago, everything was working fine. I have noticed this problem a few months ago (probably after a DSM update).

Has anyone also come across this issue or has a clue on how to get it working again? Thanks!

Answer 1

I had this exact same problem. GCC use to work and now with DSM 6.1 it broke. I think it's after they switched to 64-bit with DSM 6.0 I believe. Your question actually gave me the answer so I wanted to share it here. I changed /lib/libc.so.6 to /lib32/libc.so.6 in the file /opt/lib/libc.so.

$ cat /opt/lib/libc.so 
/* GNU ld script
   Use the shared library, but some functions are only in
   the static library, so try that secondarily.  */
OUTPUT_FORMAT(elf32-i386)
GROUP ( /lib32/libc.so.6 /opt/lib/libc_nonshared.a )

After making the change above optware GCC compiled my test file without any environment variables set just like you would expect on a normal Linux system.