Using public headers to write ABI vscripts

[Alexander Bokovoy]

On Fri, Aug 31, 2012 at 9:06 AM, Andrew Bartlett <abartlet at samba.org> wrote:
> On Fri, 2012-08-31 at 08:31 +0300, Alexander Bokovoy wrote:
>> Hi Andrew,
>>
>> On Wed, Aug 29, 2012 at 7:54 AM, Andrew Bartlett <abartlet at samba.org> wrote:
>> > I've been working on a patch to use the mksyms.awk approach to get a
>> > list of public headers and symbols from our public headers files, and
>> > use that instead of just the regular-expression abi_match.
>> >
>> > https://git.samba.org/?p=abartlet/samba.git/.git;a=shortlog;h=refs/heads/abi-public-headers
>> >
>> > It would be great to get this in to 4.0, but I'm having some waf
>> > challenges I'll need to get past.  The challenge relates to the grouping
>> > from the build ordering, because we need a vscript for libreplace (very
>> > early) but vscripts can depend on pild-generated headers.  We may need
>> > to rely on pure dependencies rather than also the groups.
>> >
>> > This came up because I had to bump the ldb ABI (it needed a bump for the
>> > behaviour change, but it spiked my interest) when adding a private,
>> > internal symbol.
>> I'm also working in this area though my needs are bit different at the moment.
>>
>> https://git.samba.org/?p=ab/samba.git/.git;a=shortlog;h=refs/heads/stableabi
>> has number of patches that attempt to introduce API namespaces.
>>
>> I need stable mapping between API namespace and version node name
>> associated with it that spans across multiple releases (instead of
>> SAMBA_<VERSION> default symbol changing every release without actual
>> semantical and ABI change) for certain important private libraries.
>
> I'm a bit confused.  In what sense is a library that is being linked
> from outside our build process still private?
libpdb is required to link against if you are passdb module. FreeIPA
provides its ipasam module and it needs to link against libpdb to be
useful in smbd.It is consumed purely by smbd and thus still considered
private but the source code lives outside samba source tree and thus
public.

> I don't like the idea of public users of our private libraries.  If we
> wish to declare a library open for public use, shouldn't it just be
> given a version number and be declared as public?
libpdb includes all sorts of things, not only API that is used by the
modules. For example, all statically compiled pdb modules are compiled
into libpdb.

-- 
/ Alexander Bokovoy