Re: [Xenomai] xenomai-3.0-rc5 : binding named semaphores from external process

[Philippe Gerum <rpm@xenomai.org>]

On 07/30/2015 04:28 PM, Frederik Bayart wrote:
>> On 07/29/2015 08:27 PM, Philippe Gerum wrote:
>>>
>>> Please merge the commit on top of -rc6 I mentioned this morning, which
>>> fixes the spurious wake up:
>>>
>>> http://git.xenomai.org/xenomai-3.git/commit/?h=next&id=081cbb8b150f30a019245dfb0e2f0b92cc7f2dfd
>>>
>>
>> Actually, I did not mention it, that's why we don't seem to be on the
>> same page, sorry for this. We should resume the discussion from the
>> situation obtained with this commit on top of -rc6.
> 
> I have build a new rc6 kernel & libraries with the new kernel/cobalt/posix/sem.c
> The rt_sem_p problem is now solved, the first process is not interrupted anymore.
> 
> I still doesn't see the fuse file system like you do.  I'm looking to other problems (select/connect/send/recv on UNIX domain sockets) so I hope that this is not the cause.
> 
> I found already that 'select' on  socket(PF_UNIX, SOCK_STREAM, 0)  causes Interrupted system call (errno 4).
> If I replace 'select' with '__real_select' the problem seems to be solved, and the select timeout works.
> But the select doesn't seem to react on connect. I'm looking at the problem.
> 
> Maybe I will see more if I build with --enable-debug.
> 
> This is the fuse data of the system :
> 
> $ sudo ./stest  --dump-config|grep REGISTRY
> based on Xenomai/cobalt v3.0-rc6 -- 
> CONFIG_XENO_REGISTRY=1
> CONFIG_XENO_REGISTRY_ROOT="/var/run/xenomai"
> 
> Is this what I'm supposed to see ?
>

Yes.

> I configured CONFIG_FUSE_FS=m in the kernel, module fuse is loaded.
> The fuse packages are installed :
> ii  fuse            2.9.3-15+b1  amd64    Filesystem in Userspace
> ii  gvfs-fuse        1.22.2-1    amd64    userspace virtual filesystem - fuse server
> ii  libfuse-dev      2.9.3-15+b1  amd64    Filesystem in Userspace (development)
> ii  libfuse2:amd64  2.9.3-15+b1  amd64    Filesystem in Userspace (library)
> 
> $ xeno-config --info
> Xenomai version: Xenomai/cobalt v3.0-rc6 -- 
> Linux dev-x10sae 3.18.12-x86-64-xeno-3.0.rc6.1 #1 SMP PREEMPT Thu Jul 30 12:38:10 CEST 2015 x86_64 GNU/Linux
> Kernel parameters: BOOT_IMAGE=/boot/vmlinuz-3.18.12-x86-64-xeno-3.0.rc6.1 root=UUID=fc8ecefa-fc73-487f-a045-cffa99c38a11 ro quiet console=tty0 console=ttyS0,115200n8
> I-pipe release #1 detected
> Cobalt core 3.0-rc6 detected
> Compiler: gcc version 4.9.2 (Debian 4.9.2-10) 
> Build args: --prefix=/usr --includedir=/usr/include/xenomai --mandir=/usr/share/man --with-testdir=/usr/lib/xenomai/testsuite --with-core=cobalt --enable-smp --enable-pshared --enable-registry --build x86_64-linux-gnu build_alias=x86_64-linux-gnu
> 
> 
> If I run the 2 stest processes, this is what I see :
> $ find /var/run/xenomai/
> /var/run/xenomai/
> /var/run/xenomai/root
> /var/run/xenomai/root/foo
> /var/run/xenomai/root/foo/20678
> /var/run/xenomai/root/foo/20667
> /var/run/xenomai/root/foo/system
> 
> $ mount | grep fuse
> fusectl on /sys/fs/fuse/connections type fusectl (rw,relatime)
> sysregd on /run/xenomai/root/foo/system type fuse.sysregd (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions)
> stest on /run/xenomai/root/foo/20667 type fuse.stest (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions)
> stest on /run/xenomai/root/foo/20678 type fuse.stest (rw,nosuid,nodev,relatime,user_id=0,group_id=0,default_permissions)

I suspect a permission issue, since you attempt to traverse the mount
points apparently with regular user privileges. Any luck with "sudo find
..." ?

Alternatively, passing --shared-registry to your app would enable public
access to the registry of your application.

-- 
Philippe.