Re: Problem building a version update of rng-tools

[Adolf Belka <adolf.belka@ipfire.org>]

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Hi Michael,

On 03/05/2023 17:57, Adolf Belka wrote:
> Hi Michael,
>
> On 03/05/2023 17:39, Michael Tremer wrote:
>> Hello Adolf,
>>
>>> On 3 May 2023, at 14:23, Adolf Belka <adolf.belka(a)ipfire.org> wrote:
>>>
>>> Hi Michael,
>>>
>>> On 03/05/2023 14:58, Adolf Belka wrote:
>>>>
>>>> On 03/05/2023 14:35, Adolf Belka wrote:
>>>>> Hi Michael,
>>>>>
>>>>> On 03/05/2023 14:07, Michael Tremer wrote:
>>>>>> Hello Adolf,
>>>>>>
>>>>>> Normally you should not need to add anything extra for this to work. The compiler should know where to search for libraries.
>>>>>>
>>>>>> If pkg-config is being used, this might be a little bit different.
>>>>> Just before the various packages are checked to exist the configure also checks that pkg-config is existing.
>>>>>>
>>>>>>> On 3 May 2023, at 13:02, Adolf Belka <adolf.belka(a)ipfire.org> wrote:
>>>>>>>
>>>>>>> Hi All,
>>>>>>>
>>>>>>>
>>>>>>> There is a new version for rng-tools so I thought I would do an update but it kept stopping saying that it required libcap and could not find it.
>>>>>>>
>>>>>>> I noted that the libcap libs are in /lib and not in /usr/lib as the other packages that rng-tools looks for have their libs. (openssl, libxml2, curl, jansson)
>>>>>>>
>>>>>>> The new version has a flag for the ./configure called libcap_LIBS which can be used to override pkg-config.
>>>>>>>
>>>>>>> I tried that in various ways such as libcap_LIBS="/lib" or libcap_LIBS="/lib/libcap.so.2.67" and others, but none of them worked. The ./configure still ended up with the message
>>>>>>>
>>>>>>> checking for libcap... no
>>>>>>> configure: error: libcap is required
>>>>>>>
>>>>>>> I then noticed that libcap.pc is in /lib/pkgconfig/ while all the other packages being searched for are in /usr/lib/pkgconfig/
>>>>>>
>>>>>> This should indeed be installed to /usr/lib/pkgconfig.
>>>>>>
>>>>>> I don’t have a problem with simply changing —-prefix=/ to —-prefix=/usr for libcap, because we don’t support a split /usr directory anyways. That should make it easier.
>>>> Looking through the libcap README and Makefile then the .pc files should be getting placed in /usr/lib/pkgconfig but they aren't. Also as $(prefix) is not defined then the prefix should be /usr but again it is not.
>>>
>>> I think I must have misread what the Makefile etc were intending to do.
>>>
>>> I just tried a quick build of libcap with adding prefix=/usr to the make and make install lines and the lib files and the .pc files are now in /usr/lib/ and /usr/lib/pkgconfig/
>>>
>>> The only remaining question I have is if anything else in IPFire would be expecting to see the lib files for libcap in /lib/ instead of /usr/lib/ because then the symlinking of the lib from /lib/ to /usr/lib/ won't be needed any more.
>>
>> No, pkg-config should never search in /lib.
> Okay, that is good to know.
>>
>>> What is libcap used for so I can test out the built iso on a vm machine?
>>
>> It is quite widely used to manage capabilities of a running program. I can give some privileges away and limit itself so that any remote code executing could not cause too much damage for example.
>>
>> /usr/bin/ping is for example linked against libcap. If you can execute it, everything is fine.
> That is a nice easy test then.
>
> The build of libcap with prefix=/usr successfully built but it also placed the capsh, getcap, getpcaps and setcap binaries from /sbin to /usr/sbin so the change was not as easy as I thought. Maybe I should only have the prefix=/usr in the make line and not in the make install line.
>
> Will have another look in the makefile and see how the location for capsh etc are defined.
>
Discovered that I also had to define exec_prefix as blank, then those executable files were placed in /sbin again.


Regards,

Adolf.

> Regards,
> Adolf.
>>
>>> Regards,
>>>
>>> Adolf.
>>>
>>>>> libcap currently keeps the library files in /lib/ but makes a symlink to one of them in /usr/lib/. Libcap doesn't have a configure line. There is a sed command on the Makefile to stop it building static libs and then it goes straight to make and then make install
>>>>>>
>>>>>>> I then manually did a copy of libcap.pc to /usr/lib/pkgconfig/ and then re ran just the rng-tools build and it then successfully found libcap and completed the build. So the problem is definitely to do withy the unusual location for the library files of libcap.
>>>>>>
>>>>>> Do we have any other packages that install .pc files into funny places?
>>>>> The other .pc files that are in /lib/pkgconfig/ are libkeyutils, libproc-2, libpsx and libsysfs
>>>>>>
>>>> The libpsx.pc file is also from libcap.
>>>>>>> So the question I have is what is the best way to deal with this.
>>>>>>>
>>>>>>> Should I add into the libcap lfs a line that copies the libcap.pc to /usr/lib/pkgconfig/ or
>>>>>>>
>>>>>>> is can someone tell me what I am doing wrong with the libcap_LIBS flag for ./configure
>>>>>>>
>>>> I think that rather than trying to adjust libcap to work the way it says it should be anyway, I will add a copy line into the lfs to move the libcap.pc file to /usr/lib/pkgconfig/
>>>>
>>>>
>>>> Regards,
>>>>
>>>> Adolf.
>>>>
>>>>>>>
>>>>>>> Regards,
>>>>>>>
>>>>>>> Adolf.
>>>>>>>
>>>>>>
>>>>>> -Michael
>>
>>