On 08/06/2012 01:20 PM, Michał Górny wrote:
Ok, a few comments from me.
On Mon, 06 Aug 2012 13:00:08 +0300
Samuli Suominen <ssuomi...@gentoo.org> wrote:
--- systemd.eclass 2012-08-06 12:49:20.532528219 +0300
+++ /tmp/systemd.eclass 2012-08-06 12:57:28.333542735 +0300
First of all, I'm not really convinced systemd.eclass is a good place
for this.
The main reason for introducing a separate systemd.eclass was to have
a single place to control installing systemd unit files. The rule is
quite simple here: you install systemd unit files, you inherit
the eclass.
Most importantly, this allows us to easily find out which packages
install such files and perform global operations on them. For example,
if a particular user had systemd locations in INSTALL_MASK and changed
his mind, he can easily update his system by rebuilding all packages
inheriting systemd.eclass.
If all packages installing udev rules start inheriting it, the above
will no longer be correct. Also, the opposite way -- rebuilding
packages installing udev rules -- won't be that easy.
That's not my call but I believe that putting those functions in
separate udev.eclass could be the best course of action, for the reason
stated above -- we can easily find out what installs them, and rebuild
it all at once.
OK, we can make it udev.eclass and then we can add the virtual/pkgconfig
and sys-fs/udev dependency of it.
@@ -25,6 +25,8 @@
# }
# @CODE
+inherit toolchain-funcs
+
case ${EAPI:-0} in
0|1|2|3|4) ;;
*) die "${ECLASS}.eclass API in EAPI ${EAPI} not yet
established." @@ -34,6 +36,31 @@
DEPEND="!<sys-apps/systemd-29-r4
!=sys-apps/systemd-37-r1"
+# @FUNCTION: _systemd_get_udevdir
+# @INTERNAL
+# @DESCRIPTION:
+# Get unprefixed udevdir.
+_systemd_get_udevdir() {
+ if $($(tc-getPKG_CONFIG) --exists udev); then
+ echo -n "$($(tc-getPKG_CONFIG) --variable=udevdir
udev)"
Secondly, I believe you shouldn't do such a thing *without* depending
on udev. Even though there is fallback here, there is another problem:
you are introducing a *potential inconsistency* between built packages,
depending on contents of udev.pc. Thus, I believe the package should
depend on the package providing it so that the dependency tree is
complete.
OK, I can agree with udev.eclass as I stated before already.
Also, I'm not so sure if this will work correctly for Prefix.
I'm sure that is easily checked and we will get feedback quickly.
+ else
+ echo -n /lib/udev
+ fi
+}
And finally, I believe we shouldn't even be making the install location
variable.
It's the upstream way to determine the path and is used treewide by
upstream configure scripts etc. for various packages already.
> Right now, the Gentoo location for udev rules is /lib/udev,
and I believe William will agree with me on this. We hadn't decided on
moving them, and thus all udev and systemd versions in the tree *will*
support /lib/udev (I still need to commit patched systemd).
If we decide to move rules to /usr/lib/udev, I believe we will move
them all at once. And then all users will have to use a newer
(or patched) udev supporting the new location (or both). In order to
enforce that, the eclass would have to block old udev versions (like
the systemd.eclass blocks old systemd versions).
The udevdir is whatever udev.pc determines it to be, and currently in
~arch it's set to /usr/lib/udev
Therefore the Gentoo udevdir is also /usr/lib/udev for ~arch
As in, packages in tree are using it already, independent of getting
this helper function to tree or not.
Making the install location dynamic is just asking for trouble.
Consider the following: user installs new udev, rebuilds package, then
downgrades udev. Package rules no longer work. That's what we would
like to avoid.
Downgrading is never a good idea when you don't know what you are doing.
+
+# @FUNCTION: systemd_get_udevdir
+# @DESCRIPTION:
+# Output the path for the udev directory (not including ${D}).
+# This function always succeeds, even if udev is not installed.
+# Dependencies need to include sys-fs/udev or otherwise
+# the fallback return value is /lib/udev.
+systemd_get_udevdir() {
+ has "${EAPI:-0}" 0 1 2 && ! use prefix && EPREFIX=
+ debug-print-function ${FUNCNAME} "${@}"
+
+ echo -n "${EPREFIX}$(_systemd_get_udevdir)"
+}
+
# @FUNCTION: _systemd_get_unitdir
# @INTERNAL
# @DESCRIPTION:
As a final note, please note that this is mostly my opinion as systemd
maintainer. I believe William has a final word on udev itself.
Summarizing:
- Will call this udev.eclass and add the dependencies for udev and
pkg-config
- Gentoo's udevdir is already set to /usr/lib/udev by
>=sys-fs/udev-187-r1 in Portage, and is widely queried by upstream
configure scripts
We should leave it like it is now, and get this helper function ASAP in
tree to get things consistent again
- Samuli
