Re: [PATCH] dhcp: Update to 4.2.3-P2

[Andrei Gherzan <andrei@gherzan.ro>]

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On 02/08/2012 07:00 PM, Phil Blundell wrote:
> On Wed, 2012-02-08 at 14:30 -0200, Otavio Salvador wrote:
>> On Wed, Feb 8, 2012 at 14:10, Phil Blundell<philb@gnu.org>  wrote:
>>          This isn't just a straightforward update, you seem to be
>>          moving dhclient
>>          from ${base_sbindir} to ${sbindir}.  If that's a good thing
>>          (which
>>          doesn't seem totally obvious to me) then it ought at least to
>>          be
>>          mentioned in the commit message.
>>
>>
>> He is doing that because it links against libcrypt that is at
>> ${libdir}. But it clearly needs to be in another commit or, at least,
>> explicit in the changlog.
> Yeah, I guessed it was probably something like that.  But this seems
> like a bad solution since anybody who has /usr separate probably does
> want dhclient during bootup.  In particular, if you have /usr on NFS
> then you might be hosed if dhclient is in /usr/bin.
>
> It seems like the right way to fix this is one of:
>
> a) move libcrypto to ${base_libdir}, or
> b) stop dhclient from linking against libcrypto, or
> c) make it link against the static rather than shared library
>
> Do we know why dhclient has grown this dependency on libcrypto in the
> first place?  Or, as an alternative data point, is there a particular
> reason why this upgrade is required (i.e. could we just stick with the
> old version)?
>
There is no "grown dependency on libcrypto" in this version. It used to 
be in last version we had as well but as this is a warning, i guess it 
was ignored as other QA warning are present in a core-image-minimal 
build for example.
Here is the log from a build where it used to be dhcp 4.2.0 (last 
version in yocto):

    dhcp-4.2.0: dhcp: {build
    path}/tmp/work/armv7a-vfp-neon-poky-linux-gnueabi/dhcp-4.2.0-r5/packages-split/dhcp-client/sbin/dhclient
    links to something under exec_prefix
    dhcp-4.2.0: ldd reports: <----->libcrypto.so.1.0.0 => {build
    path}/tmp/sysroots/vexpressa9/usr/lib/libcrypto.so.1.0.0 (0xdead1000)


So this is not a new thing. In 4.2.3 this library check and linkage is 
removed - from 4.2.1 rel notes:

    - ./configure on longer searches for -lcrypto to explicitly link against.
       This fixes a bug where 'dhclient' would have shared library dependencies
       on '/usr/lib'.  [ISC-Bugs #21967]


While integrating the new version of dhcp, the compile stage used to fail:

    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/sysroots/imx53qsb/usr/lib//libdns.a(openssldh_link.o):
    In function `openssldh_fromdns':
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:344:
    undefined reference to `DH_new'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:387:
    undefined reference to `BN_bin2bn'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:435:
    undefined reference to `DH_free'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:425:
    undefined reference to `BN_bin2bn'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:430:
    undefined reference to `DH_free'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:409:
    undefined reference to `BN_bin2bn'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:410:
    undefined reference to `BN_cmp'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:411:
    undefined reference to `BN_free'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:438:
    undefined reference to `BN_bin2bn'
    |
    /home/agherzan/work/wrs/yocto-adige/2012-02-08-12-18-imx53/tmp-eglibc-eglibc/work/armv7a-vfp-neon-oe-linux-gnueabi/bind-9.8.1-r2/bind-9.8.1/lib/export/dns/../../../lib/dns/openssldh_link.c:441:
    undefined reference to `BN_num_bits'


so i had to add this -lcrypto check back in configure.

At that point i didn't realize that this change could create problems 
with lcrypto.

omapip needs libdns.a and libisc.a from bind, which needs lcypto. Client 
needs omapip. So this is the way things are linked around. This is why 
in the end omapip needs lcrypto.
For example libdna.a contains openssl_link.o - openssl_link.c. In 
dst__openssl_init function we have references to:
CRYPTO_num_locks
OPENSSL_config

All these from lcrypto.


To sum it up:
1. lcrypto / dhclient is not a new problem
2. -lcryto was present in LIBS in the last yocto version of dhcp
3. Your "commit message" observations are correct. I will be a little 
more careful about this.
4. My opinion on this would be to

@g

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