Pthreads library broken in DSM3/1337 on ARM ?

[nelek]

I've already posted a similar question, but I'd like to get some feedback from the modders community if they are experiencing the same issue, or if its just me.

It seems that no matter what I try, I cannot get to compile any packages that make use of the pthread library on my ARM based Synology NAS. I have a 410j running DSM3/1337. Configure scripts of linux software that makes use of pthreads don't detect my phtreads library, although I've installed all header files which are detected properly and libpthread.so.0 is present in /lib.

Sofar I've tried the following :

1) replacing the config.guess and config.sub files from these packages with more up to date variants;
2) feeding --libdir=/lib to the configure script;
3) Exporting the environment variables for the correct library directories before compiling;
4) When comparing with DSM3-1337 on powerpc, we noticed that several aliases were missing in /opt/lib, so I went ahead and created symlinks for them :
/opt/lib/libpthread-0.10.so -> /lib/libpthread.so.0
/opt/lib/ libpthread.so.0 -> /lib/libpthread.so.0

These packages compile fine on DSM3/ppc and on several x86 2.6 Linux based distributions (Ubuntu 10.10, Debian Etch)

Either I'm missing something trivial and inobvious, or something is seriously busted on DSM3 on ARM. Anyone have thoughts on where to look further to solve this issue? Or have an idea for a working workaround?

Thanks!

[nelek]

Researching this a bit further, it seems like something is seriously busted with the pthread libraries provided by ipkg. The problem can easily be reproduced by doing the following :

Make a test.c file containing :

Code: Select all

int main(int argc, char **argv)
{
return 0;
}


then typing :

Code: Select all

gcc test.c -o test.exe -lpthread

to compile the source file which should result in the following errors :

Code: Select all

/opt/lib/gcc/arm-none-linux-gnueabi/4.2.3/../../../../arm-none-linux-gnueabi/lib/libpthread.so: undefined reference to `__default_sa_restorer_v2@GLIBC_PRIVATE'
/opt/lib/gcc/arm-none-linux-gnueabi/4.2.3/../../../../arm-none-linux-gnueabi/lib/libpthread.so: undefined reference to `__default_rt_sa_restorer_v2@GLIBC_PRIVATE'
/opt/lib/gcc/arm-none-linux-gnueabi/4.2.3/../../../../arm-none-linux-gnueabi/lib/libpthread.so: undefined reference to `__default_rt_sa_restorer_v1@GLIBC_PRIVATE'
/opt/lib/gcc/arm-none-linux-gnueabi/4.2.3/../../../../arm-none-linux-gnueabi/lib/libpthread.so: undefined reference to `__default_sa_restorer_v1@GLIBC_PRIVATE'


Workaround

1) backup the pthread libraries found in /opt/arm-none-linux-gnueabi/lib/ :

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mkdir /opt/arm-none-linux-gnueabi/lib_disabled
mv /opt/arm-none-linux-gnueabi/lib/libpthread* /opt/arm-none-linux-gnueabi/lib_disabled


2) Copy the pthread libraries found in /opt/lib

Code: Select all

cp /lib/libpthread.so.0 /opt/arm-none-linux-gnueabi/lib/
cd /opt/arm-none-linux-gnueabi/lib/
ln -s libpthread.so.0 libpthread.so
ln -s libpthread.so.0 libpthread-2.5.so


Crude workaround, but it works. Packages can now properly detect pthreads.

[mbeddow]

Many thanks for figuring this out, and for troubling to post the solution that nobody else could apparently help you with.

Your posting here is especially valuable, because anyone trying to Google a solution will hit a very large number of posts stemming from the same error messages on some Solaris boxes, but the cause and remedy there are totally different from what the ipkg-based platforms require.

Your workaround finally makes it possible to compile Apache2.2 from source (including the htpasswd utility that isn't in the DSM3 version of Apache)

If anybody wants to try Apache 2.2 compilation, there's one more step to avoid the build failing with lpthread resolution errors. You need to add -lpthread to the linker parameters, because the Apache configure script as shipped doesn't put it there.

[trvrnrth]

Just a quick note to add another word of thanks, this solved my problems compiling libtorrent-rasterbar at the weekend.

[kvicho]

Just a small note and BIG thanks!! I was trying to compile Bacula backup on my DS 409 and it kept failing until I found your article. Well done and thanks again.

[jsolomon]

I spent hours before I found this article which solved my problems. I was stuck at step 3, as I didn't know I had to export the variables. Thanks!

[Zakhar]

Many thanks for this solution.

As libpthread.so.0 in the /opt/armel..../lib is a symbolic link to the real library, I just replaced it to a link towards the working library under /lib