Re: Error when Glib cross compiled into Mini-OS without the support of "_POSIX_THREADS"

[Antti Kantee <pooka@iki.fi>]

On 25/09/14 12:55, Ian Campbell wrote:
> On Thu, 2014-09-25 at 20:50 +0800, Lele MA wrote:
>>
>>> AFAIK mini-os doesn't supply a POSIX thread API, correct.
>>>
>>> I don't think anything else in the current stubdom infra (e.g. newlib)
>>> supplies one either.
>>>
>>>> If so, can I still use the glib in the Mini-OS without the support of
>>>> "_POSIX_THREADS"?
>>>
>>> That would be a question for the glib maintainers. At a minimum I'd
>>> expect you would need to port glib to the mini-os thread API.
>>>
>>> But, before you go down that route I think you should consider the new
>>> rumpkernels work which is going on.
>>>
>>> rumpkernels run on a mini-os/Xen and provide a BSD derived POSIX like
>>> environment, which I expect will include pthreads. Depending on your
>>> application it may well be very worthwhile to start from that (I think
>>> it most likely would be, but I don't know what you are actually doing).

Yes, there's support for pthreads with rump kernels on Xen (uses 
unmodified NetBSD libpthread).

>> Thank you so much!
>>
>> My ultimate goal is to use libvmi in mini-os. And libvmi needs glib's support. So I needs to cross-compile glib into mini-os firstly.
>>
>> The mini-os kernel is essential for our project,
>
> Note that rumpkernels use mini-os (or at least large parts of it) under
> the hood. I'd strongly recommend you investigate rumpkernels before
> embarking on any direct porting work.

Yes, it uses minios in a sort of "firmware" sense.  You can still access 
the underlying minios from applications running as part of rumprun-xen 
... though generally speaking it's better to access things through one 
API instead of multiple.

The application-side interfaces (POSIX, TCP/IP, etc.) offered by 
rumprun-xen are complete enough that off-the-internet applications have 
a good chance of "just working" without any porting.

>>   so I probably have to port the glib to mini-os thread API. Can you
>> give me some tips on how to port a thread API ?
>
> I've no idea what it actually looks like, sorry. You'll probably need to
> dize into the code.
>
>> I am a newbie to mini-os thread
>> API, any help would appreciated. Thank you!

If you really want to roll your own, you can check how libpthread for 
rumprun-xen is integrated:
https://github.com/rumpkernel/rumprun-xen/blob/92b81fde24beb5dfaec1c2eec3960a61cc6dd5e0/lib/_lwp.c

Note: the above implements the _lwp API of NetBSD, which is what NetBSD 
libpthread uses to control the kernel threads it manages.  The 
integration points to minios should be quite clear, nonetheless: 
create_thread(), block(), wake(), schedule(), ...

   - antti