NT Port of SLAPD and Dynamic module

[Eric Ma <ema@nc.com>]

I work in Network Computer Inc and our development group will use slapd
to build part of our product.  Specifically, we will be using slapd with
our own database backend on both the Solaris and NT platforms.  I
understand there are specific license requirements for the use of
openldap source code and binaries.  And we are implementing changes over
standard OpenLDAP releases so that we will comply with the license
requirements and our product-specific database backend will be separate
from the main SLAPD application so we don't need to release the source
code of our database backend when we ship our product.  Our changes to
the main SLAPD application will, of course, will merged back into the
main OpenLDAP development, wherever appropriate.

At this point, we have identified two main areas for enhancement and
have had initial successes in their implementation.  I understand
independant efforts have been made in these areas by different people
under OpenLDAP, so our work may have overlapped.  My goal at this point
is to synchronize our changes with the main development in OpenLDAP.

I have done an initial NT port of SLAPD using Visial C++ 5.0.  I have
also added dynamic loading of modules for database backends via shared
libraries on Solaris and via DLLs on NT.  The purpose of the latter is
to separate our database backend from the main SLAPD applications so our
database backend is not governed by the OpenLDAP license and we don't
need to release its source code, etc.  I have tried to minimize the
changes to OpenLDAP source and the diffs are listed below:

Changes for NT Port of SLAPD using Visual C++ 5.0:
        errno.h:    defines also EWOULDBLOCK
        signal.h:   defines SIGNAL as (void)
                    gives numeric values to SIGHUP, PIPE, USR1 and USR2
        socket.h:   rearranges some macros to define macro tcp_close as
                    closesocket win32
        string.h:   ifdef's out definitions of strdup, strcasecmp and
                    strncasecmp for win32 because of prior declaration
        syslog.h:   defines openlog and syslog as (void)
        ldap_cdefs.h:  typedef void *caddr_t;
        portable.h: a lot of changes to capabilities settings specific
to
                    win32
        detach.c:   disables detaching from terminal; so slapd always
runs in
                    the foreground
        thr_posix.c:   ldap_pvt_thread_kill becomes no op; pthread
packages
                       does not define pthread_kill
        daemon.c: remaps NT sockets to array of file descriptors, since
NT
                  does not allocate sockets between 0 and FD_SETSIZE,
but 
                  any number potentially larger than FD_SETSIZE
        lock.c:   disables file locking for now
        main.c:   In main, also initializes socket DLL on win32
        socket.c: function to initialize winsock2 (initwinsock)
        
Changes in SLAPD for dynamic module support:
        dlfcn.h:  Unix-style interface for shared library (dlopen, etc)
        attr.c:   exports attr_merge (via LDAP_F) to dynamic module
        backend.c:  in new_backend, add new backend type "ldmod" for
dynamic
                    module
        ch_malloc.c:  exports ch_calloc and ch_strdup to dynamic module
        dn.c:     exports dn_normalize_case to dynamic module
        entry.c:  exports entry_free to dynamic module
        ldmod.c:  implements new backend "ldmod" for dynamic module
        proto-slap.h:  modifies prototypes of various functions by
adding
                       LDAP_F for export to dynamic module
        result.c: exports functions to dynamic module
        dlfcn.c:  wraps win32 dynamic library loading with dlfcn
interface

A few notes also:
1)  In the slapd.conf file, the following lines load a certain dynamic
module.
        database ldmod
        module /full_path_to_dll/mydll.dll  (or .so on solaris)
2)  Certain functions still need to be tagged LDAP_F for full dynamic
    support.
3)  For now, I implemented a null module that does bind and some simple
    searches; it is 
    dynamically loaded as a shared library on Solaris and DLL on win nt.
4)  detach.c should implements a windows service but is a no-op for now.
5)  None of the existing database backends have been ported yet (ldbm,
    shell, etc).
6)  The pthread library being ported by CYGNUS and the hs_regex library
    are being used.
7)  More testing is needed.
8)  openlog and syslog need to be implemented in terms of events to the
    events viewer on win32.
9)  Depending on how signals are used, implement signals on win32.

That's about it.

Your comments are appreciated.

Thanks.

Eric Ma
ema@nc.com