symlinks of glibc shared libs to musl libc.so

symlinks of glibc shared libs to musl libc.so

[sylvain.bertrand]

Hi,

I have some binaries which are dependent on glibc shared libs (except libgcc_s) and the glibc dynamic loader.
For instance: libdl, libpthreads... 

Do symlinks on libc.so based on glibc sonames give me a chance to make them work? (in
theory yes, since the symbols are there).

regards,

-- 
Sylvain

Re: symlinks of glibc shared libs to musl libc.so

[Rich Felker]

On Mon, Jul 10, 2017 at 01:36:40AM +0000, sylvain.bertrand@gmail.com wrote:
> Hi,
> 
> I have some binaries which are dependent on glibc shared libs (except libgcc_s) and the glibc dynamic loader.
> For instance: libdl, libpthreads... 
> 
> Do symlinks on libc.so based on glibc sonames give me a chance to make them work? (in
> theory yes, since the symbols are there).

Are you asking about trying to run glibc-linked binaries with musl
libc.so? For that usage, if it works, there is no need to make
symlinks for other standard posix library names like libdl.so or
libpthread.so or libm.so. They inherently always resolve to libc, and
will not actually be loaded from a file when requested.

Rich

Re: symlinks of glibc shared libs to musl libc.so

[sylvain.bertrand]

On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
> On Mon, Jul 10, 2017 at 01:36:40AM +0000, sylvain.bertrand@gmail.com wrote:
> > Hi,
> > 
> > I have some binaries which are dependent on glibc shared libs (except libgcc_s) and the glibc dynamic loader.
> > For instance: libdl, libpthreads... 
> > 
> > Do symlinks on libc.so based on glibc sonames give me a chance to make them work? (in
> > theory yes, since the symbols are there).
> 
> Are you asking about trying to run glibc-linked binaries with musl
> libc.so?

Exactly!

From you experience and feedbacks, do you think I have a chance with the proper
glibc symlinks?

-- 
Sylvain

Re: symlinks of glibc shared libs to musl libc.so

[sylvain.bertrand]

On Mon, Jul 10, 2017 at 10:06:44AM +0000, sylvain.bertrand@gmail.com wrote:
> On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
> > On Mon, Jul 10, 2017 at 01:36:40AM +0000, sylvain.bertrand@gmail.com wrote:
> > > Hi,
> > > 
> > > I have some binaries which are dependent on glibc shared libs (except libgcc_s) and the glibc dynamic loader.
> > > For instance: libdl, libpthreads... 
> > > 
> > > Do symlinks on libc.so based on glibc sonames give me a chance to make them work? (in
> > > theory yes, since the symbols are there).
> > 
> > Are you asking about trying to run glibc-linked binaries with musl
> > libc.so?
> 
> Exactly!
> 
> From you experience and feedbacks, do you think I have a chance with the proper
> glibc symlinks?

No answer, does it mean there are too many glibc specific symbols?

-- 
Sylvain

Re: symlinks of glibc shared libs to musl libc.so

[Rich Felker]

On Tue, Jul 11, 2017 at 10:43:21AM +0000, sylvain.bertrand@gmail.com wrote:
> On Mon, Jul 10, 2017 at 10:06:44AM +0000, sylvain.bertrand@gmail.com wrote:
> > On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
> > > On Mon, Jul 10, 2017 at 01:36:40AM +0000, sylvain.bertrand@gmail.com wrote:
> > > > Hi,
> > > > 
> > > > I have some binaries which are dependent on glibc shared libs (except libgcc_s) and the glibc dynamic loader.
> > > > For instance: libdl, libpthreads... 
> > > > 
> > > > Do symlinks on libc.so based on glibc sonames give me a chance to make them work? (in
> > > > theory yes, since the symbols are there).
> > > 
> > > Are you asking about trying to run glibc-linked binaries with musl
> > > libc.so?
> > 
> > Exactly!
> > 
> > From you experience and feedbacks, do you think I have a chance with the proper
> > glibc symlinks?
> 
> No answer, does it mean there are too many glibc specific symbols?

You're going to need to clarify exactly what you mean by "proper glibc
symlinks". As I understood it, and as I told you in the part of my
reply you didn't quote, what you were talking about doing with
symlinks makes no sense, but maybe I misunderstood. Please describe in
detail what you want to achieve and what setup you're proposing/asking
if it will work.

Rich

Re: symlinks of glibc shared libs to musl libc.so

[sylvain.bertrand]

On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
> Are you asking about trying to run glibc-linked binaries with musl
> libc.so?

Yes. Any feedbacks of those who tried?

-- 
Sylvain

Re: symlinks of glibc shared libs to musl libc.so

[William Pitcock]

Hi,

On Tue, Jul 11, 2017 at 12:53 PM,  <sylvain.bertrand@gmail.com> wrote:
> On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
>> Are you asking about trying to run glibc-linked binaries with musl
>> libc.so?
>
> Yes. Any feedbacks of those who tried?

You might want to look at gcompat, which is a compatibility layer
being incubated as part of the Adelie Linux distribution (as well as
carried by Alpine).  It can run many glibc binaries through a custom
ELF interpreter that invokes the musl ELF interpreter with an
additional preload containing many glibc compatibility symbols.

https://code.foxkit.us/adelie/gcompat/tree/master

On Alpine, you could do "apk add gcompat@testing" or similar to get
it, assuming the testing repo is enabled.

William

Re: symlinks of glibc shared libs to musl libc.so

[sylvain.bertrand]

On Wed, Jul 12, 2017 at 02:03:34AM -0500, William Pitcock wrote:
> Hi,
> 
> On Tue, Jul 11, 2017 at 12:53 PM,  <sylvain.bertrand@gmail.com> wrote:
> > On Sun, Jul 09, 2017 at 10:02:21PM -0400, Rich Felker wrote:
> >> Are you asking about trying to run glibc-linked binaries with musl
> >> libc.so?
> >
> > Yes. Any feedbacks of those who tried?
> 
> You might want to look at gcompat, which is a compatibility layer
> being incubated as part of the Adelie Linux distribution (as well as
> carried by Alpine).  It can run many glibc binaries through a custom
> ELF interpreter that invokes the musl ELF interpreter with an
> additional preload containing many glibc compatibility symbols.
> 
> https://code.foxkit.us/adelie/gcompat/tree/master
> 
> On Alpine, you could do "apk add gcompat@testing" or similar to get
> it, assuming the testing repo is enabled.

Ok. Then, there is an on-going project to try to reach some binary
compatibility. This is exactly what I wanted to know. Only reasonable source
level compatibily for now.

Thanks and regards,

-- 
Sylvain