[alsa-devel] udev rules prefix
Takashi Iwai
tiwai at suse.de
Sun Nov 17 10:07:26 CET 2013
At Sat, 16 Nov 2013 14:00:19 +0000,
Ivailo Monev wrote:
>
> On 11/15/13 10:29, Takashi Iwai wrote:
> > At Fri, 15 Nov 2013 13:16:41 +0000,
> > Ivailo Monev wrote:
> >> On 11/14/13 16:14, Takashi Iwai wrote:
> >>> At Thu, 14 Nov 2013 18:49:02 +0000,
> >>> Ivailo Monev wrote:
> >>>> On 11/14/13 10:51, Takashi Iwai wrote:
> >>>>> At Thu, 14 Nov 2013 13:24:49 +0000,
> >>>>> Ivailo Monev wrote:
> >>>>>> On 11/14/13 09:42, Takashi Iwai wrote:
> >>>>>>> At Thu, 14 Nov 2013 12:08:47 +0000,
> >>>>>>> Ivailo Monev wrote:
> >>>>>>>> On 11/14/13 02:48, David Henningsson wrote:
> >>>>>>>>> On 11/13/2013 09:36 PM, Ivailo wrote:
> >>>>>>>>>> Hello,
> >>>>>>>>>>
> >>>>>>>>>> the default prefix for alsa-utils is /usr however the udev rules directory
> >>>>>>>>>> is /lib/udev/rules.d thus on setups with separate partition for /usr the
> >>>>>>>>>> binaries, from /usr/bin and /usr/sbin, will likely not be available during
> >>>>>>>>>> the boot process and the udev rule will fail to restore the state.
> >>>>>>>>>>
> >>>>>>>>>> I suggest that the udev rules directory follows the prefix or append /usr
> >>>>>>>>>> to it to resolve this.
> >>>>>>>>>>
> >>>>>>>>>> Cheers!
> >>>>>>>>> Hi,
> >>>>>>>>>
> >>>>>>>>> ALSA merely follows what udev dictates, so I think your
> >>>>>>>>> question/suggestion is better redirected on the udev (now systemd)
> >>>>>>>>> mailinglist. Or potentially that of your distro.
> >>>>>>>>>
> >>>>>>>> Actually, you are not following what udev dictates (unless I'm missing
> >>>>>>>> something).
> >>>>>>>> By default, systemd (and more importantly udev) will be installed with
> >>>>>>>> /usr prefix
> >>>>>>>> (which is wrong in it self because it blindly assumes that /usr has been
> >>>>>>>> mounted
> >>>>>>>> via initrd/initramfs where separate /usr partition is in use but let's
> >>>>>>>> not talk about
> >>>>>>>> this here).
> >>>>>>>>
> >>>>>>>>
> >>>>>>>> On 11/14/13 06:45, Takashi Iwai wrote:
> >>>>>>>>> At Wed, 13 Nov 2013 20:36:48 +0000,
> >>>>>>>>> Ivailo wrote:
> >>>>>>>>>> Hello,
> >>>>>>>>>>
> >>>>>>>>>> the default prefix for alsa-utils is /usr however the udev rules directory
> >>>>>>>>>> is /lib/udev/rules.d thus on setups with separate partition for /usr the
> >>>>>>>>>> binaries, from /usr/bin and /usr/sbin, will likely not be available during
> >>>>>>>>>> the boot process and the udev rule will fail to restore the state.
> >>>>>>>>> Not true. /lib must be always present at boot even if /usr isn't
> >>>>>>>>> mounted. That's the reason why /lib/udev was chosen as default in the
> >>>>>>>>> past.
> >>>>>>>>>
> >>>>>>>>>
> >>>>>>>>> Takashi
> >>>>>>>> You got me wrong, I know that /lib should be available on early boot
> >>>>>>>> (unless it's a
> >>>>>>>> symlink, like in Arch Linux) but the point is that since the alsa-utils
> >>>>>>>> binaries are
> >>>>>>>> installed in /usr so should be the udev rules otherwise during boot
> >>>>>>>> without /usr
> >>>>>>>> being mounted you will see error message about /usr/sbin/alsactl.
> >>>>>>> Theoretically yes, but this has been rather less problems than
> >>>>>>> creating a non-existing /usr/lib/udev in the past. That's the very
> >>>>>>> reason of hard-coded /lib/udev. Changing the default behavior is
> >>>>>>> often worse unless you really do it carefully with consideration of
> >>>>>>> compatibility with old systems.
> >>>>>>>
> >>>>>>> So, if you want to change the default, don't hard code again. Make
> >>>>>>> configure to guess the right place. A patch achieving it is welcome.
> >>>>>>>
> >>>>>>>
> >>>>>>> Takashi
> >>>>>> Ok, here is the patch:
> >>>>>>
> >>>>>> From 74faeceb26c4730d6150e726792f6eb1f257b03e Mon Sep 17 00:00:00 2001
> >>>>>> From: Ivailo Monev <xakepa10 at gmail.com>
> >>>>>> Date: Thu, 14 Nov 2013 13:13:43 +0000
> >>>>>> Subject: [PATCH 1/1] detect udevdir via pkg-config
> >>>>>>
> >>>>>> ---
> >>>>>> configure.in | 2 +-
> >>>>>> 1 file changed, 1 insertion(+), 1 deletion(-)
> >>>>>>
> >>>>>> diff --git a/configure.in b/configure.in
> >>>>>> index 3ae3209..74b891e 100644
> >>>>>> --- a/configure.in
> >>>>>> +++ b/configure.in
> >>>>>> @@ -121,7 +121,7 @@ AM_CONDITIONAL(USE_XMLTO, test x"$xmlto" = xyes)
> >>>>>> AC_ARG_WITH(
> >>>>>> [udev-rules-dir],
> >>>>>> AS_HELP_STRING([--with-udev-rules-dir],[Directory where to
> >>>>>> install udev rules to (defaults to /lib/udev/rules.d)]),
> >>>>>> - [udevrulesdir=$withval], [udevrulesdir="/lib/udev/rules.d"])
> >>>>>> + [udevrulesdir=$withval], [udevrulesdir=$($PKG_CONFIG udev
> >>>>>> --variable=udevdir)"/rules.d"])
> >>>>>> AC_SUBST(udevrulesdir)
> >>>>> This pkg-config option isn't always available. Make sure to have a
> >>>>> proper fallback to /lib/udev/rules.d. Also, update the help text,
> >>>>> too.
> >>>>>
> >>>>>
> >>>>> thanks,
> >>>>>
> >>>>> Takashi
> >>>> I'm not an autotools guru but there is PKG_PROG_PKG_CONFIG in
> >>>> configure.in which is supposed to ensure that pkg-config is installed,
> >>>> right? Besides, with_systemdsystemunitdir uses almost the same
> >>>> method as in my patch which I looked at before submitting it.
> >>> udev.pc is no hard requirement for alsa-utils, thus there is no
> >>> guarantee that "pkg-config udev" works as you expected. If it's not
> >>> installed, pkg-config doesn't complain but just gives an empty
> >>> string.
> >>>
> >>>
> >>>> Anyway, here is an updated patch that keeps things more like the
> >>>> other tests in configure.in:
> >>>>
> >>>> From b30824ef1682f3040d53c1495dae308f51a4f380 Mon Sep 17 00:00:00 2001
> >>>> From: Ivailo Monev <xakepa10 at gmail.com>
> >>>> Date: Thu, 14 Nov 2013 18:41:55 +0000
> >>>> Subject: [PATCH 1/1] detect udevdir via pkg-config
> >>>>
> >>>> ---
> >>>> configure.in | 4 ++--
> >>>> 1 file changed, 2 insertions(+), 2 deletions(-)
> >>>>
> >>>> diff --git a/configure.in b/configure.in
> >>>> index 3ae3209..e8e1e82 100644
> >>>> --- a/configure.in
> >>>> +++ b/configure.in
> >>>> @@ -120,8 +120,8 @@ AM_CONDITIONAL(USE_XMLTO, test x"$xmlto" = xyes)
> >>>>
> >>>> AC_ARG_WITH(
> >>>> [udev-rules-dir],
> >>>> - AS_HELP_STRING([--with-udev-rules-dir],[Directory where to
> >>>> install udev rules to (defaults to /lib/udev/rules.d)]),
> >>>> - [udevrulesdir=$withval], [udevrulesdir="/lib/udev/rules.d"])
> >>>> + AS_HELP_STRING([--with-udev-rules-dir=DIR],[Directory where to
> >>>> install udev rules to (default=auto)]),
> >>>> + [udevrulesdir="$withval"], [udevrulesdir=$($PKG_CONFIG udev
> >>>> --variable=udevdir)/rules.d])
> >>>> AC_SUBST(udevrulesdir)
> >>>>
> >>>> dnl Checks for header files.
> >>>> --
> >>>> 1.8.3.4
> >>>>
> >>>> If you are not happy with my patch you can write your own based
> >>>> which uses the pkg-config approach without hesitation, I will not
> >>>> get upset.
> >>>>
> >>>> And still, will you do something about separate /usr or not? Just
> >>>> asking. As stated before, this patch will not solve it but replace
> >>>> the path hard coding with a flexible method.
> >>> It's matter distributors decide. The default value is just some
> >>> value that might work. Users and distros must read the document and
> >>> give the proper configure options.
> >>>
> >>>
> >>> Takashi
> >> Sorry for the late reply.
> >>
> >> So, I get that there is a variation from distribution to distribution.
> >> But what if udevrulesdir respects the default prefix
> >> (AC_PREFIX_DEFAULT)? That way, the issue in my first email will
> >> be solved. Will a patch for it be accepted?
> > It'd break the previously working behavior.
> >
> > Simply fallback to the old value (/lib/udev/) when pkg-config gives an
> > empty string. That should suffice for both cases.
> >
> >
> > Takashi
> From 8bfe323092f08e8326dddbb6c15029845556f468 Mon Sep 17 00:00:00 2001
> From: Ivailo Monev <xakepa10 at gmail.com>
> Date: Fri, 15 Nov 2013 14:05:02 +0000
> Subject: [PATCH] detect udevdir via pkg-config, fallback to
> /lib/udev/rules.d
>
> Signed-off-by: Ivailo Monev <xakepa10 at gmail.com>
Thanks, applied.
(Though, the patch couldn't be applied as is because your mailer broke
spaces or lines, so I had to apply it manually. At the next time,
please fix MUA setup or use an attachment if it's difficult.)
Takashi
> ---
> configure.in | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/configure.in b/configure.in
> index 3ae3209..60da1fa 100644
> --- a/configure.in
> +++ b/configure.in
> @@ -120,8 +120,14 @@ AM_CONDITIONAL(USE_XMLTO, test x"$xmlto" = xyes)
>
> AC_ARG_WITH(
> [udev-rules-dir],
> - AS_HELP_STRING([--with-udev-rules-dir],[Directory where to
> install udev rules to (defaults to /lib/udev/rules.d)]),
> - [udevrulesdir=$withval], [udevrulesdir="/lib/udev/rules.d"])
> + AS_HELP_STRING([--with-udev-rules-dir=DIR],[Directory where to
> install udev rules to (default=auto)]),
> + [udevrulesdir="$withval"],
> + [udevdir=$($PKG_CONFIG udev --variable=udevdir)
> + if test "x$udevdir" = "x"; then
> + udevrulesdir="/lib/udev/rules.d"
> + else
> + udevrulesdir="$udevdir/rules.d"
> + fi])
> AC_SUBST(udevrulesdir)
>
> dnl Checks for header files.
> --
> 1.8.3.4
>
> Cheers!
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> Alsa-devel at alsa-project.org
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