[OE-core] [PATCH] util-linux: make alternatives for rev and ionice work with busybox

[Niko Mauno]

On 11/9/18 7:36 PM, Niko Mauno wrote:
> On 11/9/18 2:24 AM, Burton, Ross wrote:
>> On Thu, 8 Nov 2018 at 10:58, Pascal Bach <pascal.bach at siemens.com> wrote:
>>> Busybox can provide ionice and rev. They are both installed to /bin
>>> The corresponding util-linux variant is installed to /usr/bin
>>>
>>> This causes the following error during the do_rootfs task:
>>>
>>>> update-alternatives: renaming ionice link from /bin/ionice to 
>>>> /usr/bin/ionice
>>>> mv: cannot stat '/bin/ionice': No such file or directory
>>>
>>> Moving the util-linux binaries to /bin avoids this error.
>>
>> Isn't it simpler to just set ALTERNATIVE_LINK_NAME[ionice] =
>> "${base_bindir}/ionice" (so the system knows to use the same symlink
>> for this and busybox) instead of actually moving the binary too?
>>
>> Ross
>>
> 
> Case being that busybox has ionice and rev under /bin/ whereas 
> util-linux under /usr/bin/, I wonder would the prudent course of action 
> at this point rather be to revert the 'ionice' and 'rev' specific bits 
> that were introduced (along 'cal') in 
> http://git.yoctoproject.org/cgit/cgit.cgi/poky/commit/meta/recipes-core/util-linux/util-linux.inc?id=78db831a7b0c2361a266eb37c7cbf2e368d2280a 
> 
> 
> -Niko

I believe I've pinpointed this issue to https://git.yoctoproject.org/cgit/cgit.cgi/opkg-utils/commit/?id=fcb26339000021eb9bb711aa264247aebcfdd4ae which added link relocation support to update-alternatives script (it used to error outright in case the new symlink source differed from old one, which deviated from Debian's update-alternatives behaviour). However in the added implementation, handling of case where target rootfs root directory did not match host rootfs root directory (such as in Yocto do_rootfs context) the 'mv' call tried to relocate the symlink on host rootfs rather than target rootfs resulting in 'cannot stat' error.

I submitted a patch a moment ago to opkg-utils upstream, as well as oe-core patch to opkg-utils recipe (just in case the former takes time to propagate to Yocto):
https://lists.yoctoproject.org/pipermail/yocto/2018-November/043249.html
http://lists.openembedded.org/pipermail/openembedded-core/2018-November/275959.html

-Niko