About having a static /dev

About having a static /dev

[Antonio Ospite]

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Hi,

For my machine (a780) I'd like to have a static /dev whatever image I
build, I tried setting:
IMAGE_DEV_MANAGER = ""
IMAGE_DEVICE_TABLES = "files/device_table-minimal.txt \
                       files/device_table-ezx.txt"

But this is still not enough:
 1. the 'devices' script from initscripts keeps rewriting /dev at each
    boot, and with a layout different than one would expect by having
    IMAGE_DEVICE_TABLES set, see also
    http://bugs.openembedded.org/show_bug.cgi?id=3593

 2. If I install any package which depends on udev then udev is brought
    in and the static layout is gone at the next boot.

Any suggestion about how to get to a clean solution which can be reused
by others? I can fix 1. somehow, but for 2. I still don't have any idea.

Thanks,
   Antonio

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?
A: Top-posting.
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Re: About having a static /dev

[Phil Blundell]

On Thu, 2010-04-22 at 13:43 +0200, Antonio Ospite wrote:
>  2. If I install any package which depends on udev then udev is brought
>     in and the static layout is gone at the next boot.

I think your best option is probably to make udev be a DISTRO_FEATURE
and not set it for your own distribution.

If you genuinely want udev to be selected (for your particular DISTRO)
on a per-MACHINE basis then you'll have to invent some way to nobble its
startup script so that it just doesn't do anything on machines where it
isn't wanted.

p.

Re: About having a static /dev

[Antonio Ospite]

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On Thu, 22 Apr 2010 12:55:43 +0100
Phil Blundell <philb@gnu.org> wrote:

> On Thu, 2010-04-22 at 13:43 +0200, Antonio Ospite wrote:
> >  2. If I install any package which depends on udev then udev is brought
> >     in and the static layout is gone at the next boot.
> 
> I think your best option is probably to make udev be a DISTRO_FEATURE
> and not set it for your own distribution.
> 
> If you genuinely want udev to be selected (for your particular DISTRO)
> on a per-MACHINE basis then you'll have to invent some way to nobble its
> startup script so that it just doesn't do anything on machines where it
> isn't wanted.
>

A per-MACHINE way would be better IMHO, I am thinking about
adding a check on something like /dev/.staticdev (suggested in [1]) to
both udev init script and to the 'device' script from initscripts, and
make the image class add the /dev/.staticdev file when
IMAGE_DEV_MANAGER == "" (or maybe == "static" or "none"?)

Does this sound reasonable?

Thanks,
   Antonio

[1] http://bugs.openembedded.org/show_bug.cgi?id=3593

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

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Re: About having a static /dev

[Dr. Michael Lauer]

Am 22.04.2010 um 14:46 schrieb Antonio Ospite:

> On Thu, 22 Apr 2010 12:55:43 +0100
> Phil Blundell <philb@gnu.org> wrote:
> 
>> On Thu, 2010-04-22 at 13:43 +0200, Antonio Ospite wrote:
>>> 2. If I install any package which depends on udev then udev is brought
>>>    in and the static layout is gone at the next boot.
>> 
>> I think your best option is probably to make udev be a DISTRO_FEATURE
>> and not set it for your own distribution.
>> 
>> If you genuinely want udev to be selected (for your particular DISTRO)
>> on a per-MACHINE basis then you'll have to invent some way to nobble its
>> startup script so that it just doesn't do anything on machines where it
>> isn't wanted.
>> 
> 
> A per-MACHINE way would be better IMHO, I am thinking about
> adding a check on something like /dev/.staticdev (suggested in [1]) to
> both udev init script and to the 'device' script from initscripts, and
> make the image class add the /dev/.staticdev file when
> IMAGE_DEV_MANAGER == "" (or maybe == "static" or "none"?)
> 
> Does this sound reasonable?

Please also handle the case where we neither want an IMAGE_DEV_MANAGER
nor static device population, since we use devtmpfs.

:M:

Re: About having a static /dev

[Phil Blundell]

On Thu, 2010-04-22 at 14:46 +0200, Antonio Ospite wrote:
> A per-MACHINE way would be better IMHO, I am thinking about
> adding a check on something like /dev/.staticdev (suggested in [1]) to
> both udev init script and to the 'device' script from initscripts, and
> make the image class add the /dev/.staticdev file when
> IMAGE_DEV_MANAGER == "" (or maybe == "static" or "none"?)
> 
> Does this sound reasonable?

Yes, that sounds reasonable enough.  Or you could check for /dev being
mounted on tmpfs rather than persistent storage; you'd probably need
some check along those lines anyway to catch the devtmpfs case.

It would still be nice to have udev be a DISTRO_FEATURE as well, since
it'd suck a bit to have all that stuff installed in flash if it's never
going to be used.  But your proposal sounds basically fine to me.

p.

Re: About having a static /dev

[Koen Kooi]

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On 22-04-10 14:46, Antonio Ospite wrote:
> On Thu, 22 Apr 2010 12:55:43 +0100
> Phil Blundell <philb@gnu.org> wrote:
> 
>> On Thu, 2010-04-22 at 13:43 +0200, Antonio Ospite wrote:
>>>  2. If I install any package which depends on udev then udev is brought
>>>     in and the static layout is gone at the next boot.
>>
>> I think your best option is probably to make udev be a DISTRO_FEATURE
>> and not set it for your own distribution.
>>
>> If you genuinely want udev to be selected (for your particular DISTRO)
>> on a per-MACHINE basis then you'll have to invent some way to nobble its
>> startup script so that it just doesn't do anything on machines where it
>> isn't wanted.
>>
> 
> A per-MACHINE way would be better IMHO

That would break the case where you want static devs for one image (e.g.
initramfs, rescue fs), but other options (e.g. udev, devtempfs, mdev,
something else) for other images on the same machine.

regards,

Koen
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Re: About having a static /dev

[Koen Kooi]

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On 22-04-10 13:43, Antonio Ospite wrote:
> For my machine (a780) I'd like to have a static /dev whatever image I
> build, I tried setting:
> IMAGE_DEV_MANAGER = ""
> IMAGE_DEVICE_TABLES = "files/device_table-minimal.txt \
>                        files/device_table-ezx.txt"
> 
> But this is still not enough:
>  1. the 'devices' script from initscripts keeps rewriting /dev at each
>     boot, and with a layout different than one would expect by having
>     IMAGE_DEVICE_TABLES set, see also
>     http://bugs.openembedded.org/show_bug.cgi?id=3593

The right answer would be to have image.bbclass create /etc/device_table
from the IMAGE_DEVICE_TABLES vars during do_rootfs.

And of course mark /etc/device_table as CONFFILES in the initscripts
recipe to keep the changes on package upgrades.

regards,

Koen
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[PATCH] image.bbclass: create /etc/device_table from IMAGE_DEVICE_TABLES

[Antonio Ospite]

Right now when the 'devices' script from initscripts is called the
layout specified in IMAGE_DEVICES_TABLES is lost.

With this change the default behaviour when no IMAGE_DEVICE_TABLES is
specified is to always use files/device_table-minimal.txt

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
---
Hi Koen et al.,

This looks to be enough in my preliminary tests.
As for the default behaviour change, I guess it is acceptable and
files/device_table-minimal.txt can always be changed in a later commit, maybe
to resemble more the very /etc/device_table from initscripts.

This patch fixes http://bugs.openembedded.org/show_bug.cgi?id=3593 and I
consider it an orthogonal problem to having static /dev, so this can be
reviewed alone.

Note that I used /etc instead of ${sysconfdir} on purpose as /etc is already
hardcoded in several places in image.bbclass.

Thanks,
   Antonio Ospite
   http://ao2.it

 classes/image.bbclass                  |    4 ++++
 recipes/initscripts/initscripts_1.0.bb |    4 +++-
 2 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/classes/image.bbclass b/classes/image.bbclass
index 8e202f0..0fcbc44 100644
--- a/classes/image.bbclass
+++ b/classes/image.bbclass
@@ -119,8 +119,12 @@ fakeroot do_rootfs () {
 	mkdir -p ${IMAGE_ROOTFS}
 	mkdir -p ${DEPLOY_DIR_IMAGE}
 
+	mkdir -p ${IMAGE_ROOTFS}/etc
+
 	if [ "${USE_DEVFS}" != "1" ]; then
+		rm -rf ${IMAGE_ROOTFS}/etc/device_table
 		for devtable in ${@get_devtable_list(d)}; do
+			cat $devtable >> ${IMAGE_ROOTFS}/etc/device_table
 			makedevs -r ${IMAGE_ROOTFS} -D $devtable
 		done
 	fi
diff --git a/recipes/initscripts/initscripts_1.0.bb b/recipes/initscripts/initscripts_1.0.bb
index 2c0689f..43cf347 100644
--- a/recipes/initscripts/initscripts_1.0.bb
+++ b/recipes/initscripts/initscripts_1.0.bb
@@ -4,7 +4,7 @@ PRIORITY = "required"
 DEPENDS = "makedevs"
 RDEPENDS = "makedevs"
 LICENSE = "GPL"
-PR = "r117"
+PR = "r118"
 
 SRC_URI = "file://functions \
            file://halt \
@@ -35,6 +35,8 @@ SRC_URI = "file://functions \
 
 SRC_URI_append_arm = " file://alignment.sh"
 
+CONFFILES_${PN} += "${sysconfdir}/device_table" 
+
 KERNEL_VERSION = ""
 
 do_install () {
-- 
1.7.0.5

Re: [PATCH] image.bbclass: create /etc/device_table from IMAGE_DEVICE_TABLES

[Koen Kooi]

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On 26-04-10 17:36, Antonio Ospite wrote:
> Right now when the 'devices' script from initscripts is called the
> layout specified in IMAGE_DEVICES_TABLES is lost.
> 
> With this change the default behaviour when no IMAGE_DEVICE_TABLES is
> specified is to always use files/device_table-minimal.txt
> 
> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>

Acked-By: Koen Kooi <koen@openembedded.org>

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Re: [PATCH] image.bbclass: create /etc/device_table from IMAGE_DEVICE_TABLES

[Antonio Ospite]

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On Mon, 26 Apr 2010 18:34:06 +0200
Koen Kooi <k.kooi@student.utwente.nl> wrote:

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> Hash: SHA1
> 
> On 26-04-10 17:36, Antonio Ospite wrote:
> > Right now when the 'devices' script from initscripts is called the
> > layout specified in IMAGE_DEVICES_TABLES is lost.
> > 
> > With this change the default behaviour when no IMAGE_DEVICE_TABLES is
> > specified is to always use files/device_table-minimal.txt
> > 
> > Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
> 
> Acked-By: Koen Kooi <koen@openembedded.org>

Koen, would you push this if there are no objections?

Thanks,
   Antonio

-- 
Antonio Ospite
http://ao2.it

PGP public key ID: 0x4553B001

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing in e-mail?

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Re: [PATCH] image.bbclass: create /etc/device_table from IMAGE_DEVICE_TABLES

[Koen Kooi]

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Done, thanks for the patch!

On 28-04-10 18:14, Antonio Ospite wrote:
> On Mon, 26 Apr 2010 18:34:06 +0200
> Koen Kooi <k.kooi@student.utwente.nl> wrote:
> 
>> -----BEGIN PGP SIGNED MESSAGE-----
>> Hash: SHA1
>>
>> On 26-04-10 17:36, Antonio Ospite wrote:
>>> Right now when the 'devices' script from initscripts is called the
>>> layout specified in IMAGE_DEVICES_TABLES is lost.
>>>
>>> With this change the default behaviour when no IMAGE_DEVICE_TABLES is
>>> specified is to always use files/device_table-minimal.txt
>>>
>>> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
>>
>> Acked-By: Koen Kooi <koen@openembedded.org>
> 
> Koen, would you push this if there are no objections?
> 
> Thanks,
>    Antonio
> 
> 
> 
> 
> _______________________________________________
> Openembedded-devel mailing list
> Openembedded-devel@lists.openembedded.org
> http://lists.linuxtogo.org/cgi-bin/mailman/listinfo/openembedded-devel

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