RFC: FreeBSD DB Port Reform

[Matthias Andree]

Hi,

I am planning to reform the way the BerkeleyDB 3, 4 and 4.1 ports are
currently laid out, to reduce the mess that a BDB dependent port leaves
in Makefile and files/patch-*.

This will involve changes to all BerkeleyDB dependent ports!

I have a web site on this topic with preview tarballs of the new ports,
http://mandree.home.pages.de/freebsd-db-reform/

Here is the lynx dump of the web site:

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                      The FreeBSD BerkeleyDB Port Reform


    [1]Matthias Andree

   Revision: $Id: index.html,v 0.1 2003/11/06 11:24:33 emma Exp emma $

                                 Introduction

   The current databases/db* ports are a mess. They use nonstandard
   library names that require porters to ship a lot of FreeBSD
   files/patch-* patches to make the port compile with the non-canonical
   layout.

   I believe the layout has historical reasons in a.out. ELF, with its
   SONAME feature, allows for a more elegant and standard-conforming
   layout that allows us to drop FreeBSD specific patches from the ports.

                            Background information

     * Any ELF shared object (library), seen as .so file, bears an
       "SONAME" tag that can be made visible with "readelf -d FILENAME"
       and that needs not match the file name (it often does, see below).
     * Any ELF executable that links against shared object bears a
       corresponding "NEEDED" tag. A link time, here is recorded the
       SONAME of the .so file linked against, not the file name. Example:
       Linking a program with -L/usr/local/BerkeleyDB.4.1 -ldb will
       insert a "NEEDED: libdb-4.1.so.1" trait into the program. The
       program will, at run time, automatically choose
       /usr/local/lib/libdb-4.1.so.1. This NEEDED information is also
       visible in "readelf -d FILENAME".
     * An ELF executable MAY have one or more "RPATH" tag that specifies
       exactly one shared object search path element. It allows to
       specify the link path in an executable, and saves the end user the
       hassle of editing ld.so.conf or LD_LIBRARY_PATH for non-default
       library paths. This is, you guessed it, visible in "readelf -d
       FILENAME".

                                  Action Plan

    1. Remove db2 port (move it into the Attic). According to INDEX, not
       a single port depends on it.
    2. bsd.ports.mk should be extended to support WITH_BDB_VER,
       USE_BDB_VER or WANT_BDB_VER or something that presets a set of
       variables, for instance BDB_VERSION, BDB_INCLUDES, BDB_LIBNAME,
       BDB_LIBPATH and LIB_DEPENDS, to lift shared code out of the
       individual ports into bsd.ports.mk.
    3. for db3, db4 and db41, the following changes are made:
         1. all programs move into $PREFIX/BerkeleyDB.N.M/bin/db_*
         2. programs will no longer be renamed to db41_* db4_* or db3_*.
         3. all libraries maintain their official SleepyCat names,
            libdb-3.3, libdb-4.0, libdb-4.1, and will not be renamed to
            libdb3, libdb4 or libdb41 - this removes the need for a good
            deal or REINPLACE_CMD or patches.
         4. all libraries move into $PREFIX/BerkeleyDB.N.M/lib, because
            BerkeleyDB installs not only libdb-N.M* but also libdb-N* and
            libdb* (where * is .so.N, .so or .a), which cannot work in
            the same path.
         5. a relative symbolic link from $PREFIX/lib/libdb-N.M.so.M to
            ../BerkeleyDB.N.M/lib/libdb-N.M.so.M (the SONAME, see above)
            is maintained.
         6. documentation moves into $PREFIX/share/doc/BerkeleyDB.N.M and
            is symlinked from $PREFIX/BerkeleyDB.N.M/docs
         7. All BerkeleyDB distributions will be compiled with
            --with-uniquename, so that the same application can link two
            different DB versions without conflicts. It's not too common,
            but can happen indirectly through other libraries. See
            http://www.sleepycat.com/docs/ref/install/multiple.html for
            rationale.
            NOTE: This changes the ABI (but not the API), which means all
            applications will have to be recompiled and relinked.
    4. Dependent ports will have to be updated and recompiled, this will
       need the help of original maintainers.
    5. db2 references will be removed, the WITH_BDB_VER stuff will be
       updated to the new port directory layout, will be unified across
       all ports (so no WITH_BDB4 games as some Ruby ports do) so that it
       can move into Mk/bsd.ports.mk

                                  Advantages

     * no more makefile file patching for the arcane layout. -ldb with
       proper LDFLAGS will "just work".
     * ports that use the official library names such as -ldb-3.3,
       ldb-4.0, ldb-4.1, will also "just work".
     * ports that have --with-db switches and expect a standard
       BerkeleyDB.N.M directory under /usr/local will also "just work".
     * Fewer FreeBSD-specific patches in the ports tree will be needed.

                                 Disadvantages

   All ports that depend on DB will have to be updated once.

                                    Preview

   [2]Port tarballs for preview are here. Comments are solicited.

References

   1. mailto:matthias.andree at gmx.de?subject=FreeBSD+BDB+reform
   2. http://mandree.home.pages.de/freebsd-db-reform/ports/

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-- 
Matthias Andree

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