[Pkg-xen-devel] About hotplug/udev

[Ralph Passgang]

Am Montag, 20. Februar 2006 15:55 schrieb Julien Danjou:
> Hello,
>
> The current dependancy on hotplug|udev (>= 0.59) seems bad.
> As far as I remember, last week, when I tried to install Ralph packages,
> I got an error from hotplug/udev and I had to use udev from
> backports.org

on sarge? sarge's udev is too old (that's why I added this dependency at all). 
If you want to use udev on sarge in combination with xen then you have to use 
a backported udev in any case.

if you would compile xen from sources (not from our package) then you will 
only have the udev etc-scripts installed if your udev is newer (or equals) 
than 0.059, otherwise the hotplug etc scripts are installed. 

upstream always only installs hotplug etc scripts OR udev etc scripts and on 
sarge (without backported udev) always only hotplug. on more recent debian 
distributions udev is fine and should be useable without an issue.

you can take a look in upstream yourself, for example in upstreams install.sh 
there are the following lines:

[ -x "$(which udevinfo)" ] && \
  UDEV_VERSION=$(udevinfo -V | sed -e 's/^[^0-9]* \([0-9]\{1,\}\)[^0-9]\{0,
\}/\
1/')

if [ -n "$UDEV_VERSION" ] && [ $UDEV_VERSION -ge 059 ]; then
  cp -f $src/etc/udev/rules.d/*.rules $dst/etc/udev/rules.d/
else
  cp -f $src/etc/hotplug/*.agent $dst/etc/hotplug/
fi

> Anyone know which version of udev/hotplug we will have to depends on ?
> Maybe we could simply rely on a recent udev dependancy, because afaik
> udev now provides hotplug.

were you forced to remove udev to install my xen3 packages? if so, then we 
should change the dependcy to "hotplug | udev" again, because it's not a 
problem to have sarge's udev version installed, but in this case hotplug is 
used by xen and udev ignored. 

We could add a udev version check into xendomains or the xend init-script, so 
that sarge users will be informed that their udev version is to old and 
hotplug will be used.

but that rembers me of something that we should discuss too:

we have "hotplug" as build-dependcy. by doing this we can be sure to have the 
hotplug etc scripts installed by the normal make all/dist call. But because 
we want to have also udev support I added the "make udev-install" line in the 
rules file. But is it really clever to go this way? Wouldn't it be better to 
not build-depend on hotplug (I guess for compiling it's not needed in any 
way) and then call "make hotplug-install" & "make udev-install"?

We wouldn't have a unneeded (and for some udev users maybe frustrating) 
build-dependency + we could be sure to install hotplug and udev etc files 
anyway. 

--Ralph