[Barrelfish-users] Newlib libc ported

Timothy Roscoe troscoe at inf.ethz.ch
Mon Dec 19 17:43:39 CET 2011

Dear Zeus, 

This looks really useful - can you tell me what licence Newlib uses?

 -- Mothy

At Mon, 19 Dec 2011 17:06:24 +0100, Zeus Gómez Marmolejo <zeus.gomez at bsc.es> wrote:
> Dear Barrelfish developers,
> I would like to keep updated with our progress here at BSC. We have
> successfully ported the Redhat Newlib to Barrelfish as a libc replacement.
> To do so, some code in the posixcompat has been rewritten to not call in
> turn to the libc. This way, calls to write(), read() or sbrk() have been
> lightly modified to implement the functionality present in the existing
> libc. The objective has been to not touch the newlib.
> Right now, all programs link with newlib, being able to boot all system
> with this library. Also, in case the old library is needed, I've added a
> variable in the Config for Hake to be able to select which libc library to
> compile. Both of them are working. To do so, I had to separate includes
> that were system dependent and others that were libc dependent.
> This newlib has been included in the Barrelfish tree but can be used also
> with the independent gcc cross-compiler that we also developed here. This
> gives full C++ support with the GNU libstdc++ and exception support.
> Some technical details that I had to cope... Now all libraries (vfs,
> posixcompat, newlib, lwip, nfs...) are always linked in. Because newlib
> always needs posixcompat as it has the "system calls" implementation. Due
> to this, vfs, nfs and lwip have to be linked too as the implementation of
> read() write() have calls to vfs and nfs. In some executables, vfs is not
> needed but its linked in anyway. There was an issue with this, as
> vfs_init() was always called as it's present in the init section of the
> ELF. Some early executables in the boot process fail in the vfs_init() call
> as the ramfs is still not available. To solve this, we have placed the
> vfs_init() call at the start of the programs that use vfs, as most of them
> don't use it.
> If you wish I can send you the patch to be included in the tree...
> Kind regards,
> --
> Zeus Gómez Marmolejo
> Barcelona Supercomputing Center
> PhD student
> http://www.bsc.es

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