how to create a named_pipe in my image

how to create a named_pipe in my image

[Baumann, Michael]

Hi,

I try to create a named pipe (fifo) for my target filesystem. 
I tried it in my <image>.bb file in the do_install() section with "mkfifo <path_to_pipe_in_target_fs>"

Any ideas gratefully received.

Regards 
Michael

Re: how to create a named_pipe in my image

[Baumann, Michael]

To make my question more precise:

mkfifo in the do_install() section works. I can see the named pipe in build/tmp-glibc/work/*/*/*/ but my bitbake hangs in the  do_package_write_ipk and do_package_qa tasks.
Possibly it's because named pipes cannot be packed into an archive? If yes, how can I circumvent this?

Regards
Michael

>-----Original Message-----
>From: yocto-bounces@yoctoproject.org [mailto:yocto-
>bounces@yoctoproject.org] On Behalf Of Baumann, Michael
>Sent: Monday, February 08, 2016 4:07 PM
>To: yocto@yoctoproject.org
>Subject: [yocto] how to create a named_pipe in my image
>
>Hi,
>
>I try to create a named pipe (fifo) for my target filesystem.
>I tried it in my <image>.bb file in the do_install() section with "mkfifo
><path_to_pipe_in_target_fs>"
>
>Any ideas gratefully received.
>
>Regards
>Michael
>--
>_______________________________________________
>yocto mailing list
>yocto@yoctoproject.org
>https://lists.yoctoproject.org/listinfo/yocto

Re: how to create a named_pipe in my image

[Burton, Ross]

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On 8 February 2016 at 16:12, Baumann, Michael <Michael.Baumann@vector.com>
wrote:

> Possibly it's because named pipes cannot be packed into an archive? If
> yes, how can I circumvent this?
>

It would be interesting to see what happens if you change PACKAGE_CLASSES
to use rpm instead of ipkg.  One workaround would be to create the fifo in
a postinst.

Ross

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Re: how to create a named_pipe in my image

[Baumann, Michael]

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Thank you Ross.
Switching to rpm package showed the same behavior.
Is there another workaround than a post install script?

Regards,
Michael

From: Burton, Ross [mailto:ross.burton@intel.com]
Sent: Monday, February 08, 2016 5:15 PM
To: Baumann, Michael
Cc: yocto@yoctoproject.org
Subject: Re: [yocto] how to create a named_pipe in my image


On 8 February 2016 at 16:12, Baumann, Michael <Michael.Baumann@vector.com<mailto:Michael.Baumann@vector.com>> wrote:
Possibly it's because named pipes cannot be packed into an archive? If yes, how can I circumvent this?

It would be interesting to see what happens if you change PACKAGE_CLASSES to use rpm instead of ipkg.  One workaround would be to create the fifo in a postinst.

Ross

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Re: how to create a named_pipe in my image

[Burton, Ross]

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On 8 February 2016 at 16:39, Baumann, Michael <Michael.Baumann@vector.com>
wrote:

> Switching to rpm package showed the same behavior.
>
> Is there another workaround than a post install script?
>
>
So I had a quick look at this.  The fifo certainly ends up in the resulting
ipk at least, but as you say package_qa hangs.  It's probably encountering
a non-file and breaking somewhere.  A really nasty workaround until this is
fixed would be to put in your recipe:

python do_package_qa() {}

(to stub out the package_qa task)

Ross

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Re: how to create a named_pipe in my image

[Burton, Ross]

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On 8 February 2016 at 17:36, Burton, Ross <ross.burton@intel.com> wrote:

> So I had a quick look at this.  The fifo certainly ends up in the
> resulting ipk at least, but as you say package_qa hangs.  It's probably
> encountering a non-file and breaking somewhere.  A really nasty workaround
> until this is fixed would be to put in your recipe:
>

Found the bug - we were trying to open a fifo as a file to see if it was an
ELF binary, and reading an empty fifo blocks...  I've just send a patch to
the list that fixes this.

Ross

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