operations no longer require two distinct BN_CTX structures. This may put
more "strain" on the current BN_CTX implementation (which has a fixed limit
to the number of variables it will hold), but so far this limit is not
triggered by any of the tests pass and I will be changing BN_CTX in the
near future to avoid this problem anyway.

This also changes the default RSA implementation code to use the BN_CTX in
favour of initialising some of its variables locally in each function.

override key-generation implementations by placing handlers in the methods
for DSA and DH. Also, parameter generation for DSA and DH is possible by
another new handler for each method.

ENGINEs implement it.

static.

write external engines (and thus should require only installed openssl
headers and libs to compile without warnings). So this gets rid of recently
introduced compilation warnings (no longer including internal headers) by
including string.h directly.

OpenSSL header files.

OPENSSL_NO_DYNAMIC_ENGINE and make sure that gets defined unless
shared library support has been specifically requested.

to be prefixed with e_ instead of hw_.  They aren't necessarely hardware
engines.  The files commited here are exact copies of the corresponding
hw_ files found in crypto/engine/.

pointers passed to them whenever necessary. Otherwise it is possible the
caller may have overwritten (or deallocated) the original string data
when a later ENGINE operation tries to use the stored values.

Submitted by: Götz Babin-Ebell <babinebell@trustcenter.de>
Reviewed by: Geoff Thorpe
PR: 98

automatically.

ENGINE_TABLE-based stuff - as described in crypto/engine/README.

Associated miscellaneous changes;
 - the previous cipher/digest hooks that hardwired directly to EVP's
   OBJ_NAME-based storage have been backed out. New cipher/digest support
   has been constructed and will be committed shortly.
 - each implementation defines its own ENGINE_load_<name> function now.
 - the "openssl" ENGINE isn't needed or loaded any more.
 - core (not algorithm or class specific) ENGINE code has been split into
   multiple files to increase readability and decrease linker bloat.
 - ENGINE_cpy() has been removed as it wasn't really a good idea in the
   first place and now, because of registration issues, can't be
   meaningfully defined any more.
 - BN_MOD_EXP[_CRT] support is removed as per the README.
 - a bug in enginetest.c has been fixed.

NB: This commit almost certainly breaks compilation until subsequent
changes are committed.

recently. So comments including file names have been fixed, and copyright
notices brought up to "2001" at the same time.

error strings - the destroy handler functions unload the error strings so
any pending error state referring to them will not attempt to reference
them after the ENGINE has been destroyed.

declare their own error strings so that they can be more easily compiled as
external shared-libraries if desired. Also, each implementation has been
given canonical "dynamic" support at the base of each file and is only
built if the ENGINE_DYNAMIC_SUPPORT symbol is defined.

Also, use "void" prototypes rather than empty prototypes in engine_int.h.

This does not yet;
  (i) remove error strings when unloading,
 (ii) remove the redundant ENGINE_R_*** codes (though ENGINE_F_*** codes
      have gone), or
(iii) provide any instructions on how to build shared-library ENGINEs or
      use them.

All are on their way.

appropriate code if any of them is defined.

This change adds some basic control commands to the existing ENGINEs
(except the software 'openssl' engine). All these engines currently load
shared-libraries for hardware APIs, so they've all been given "SO_PATH"
commands that will configure the chosen ENGINE to load its shared library
from the given path. Eg. by calling;
    ENGINE_ctrl_cmd_string(e, "SO_PATH", <path>, 0).

The nCipher 'chil' ENGINE has also had "FORK_CHECK" and "THREAD_LOCKING"
commands added so these settings could be handled via application-level
configuration rather than in application source code.

Changes to "openssl engine" to test and examine these control commands will
be made shortly. It will also provide the necessary tips to application
programs wanting to support these dynamic control commands.

The existing ENGINEs (including the default 'openssl' software engine) were
static, declared inside the source file for each engine implementation. The
reason this was not going boom was that all the ENGINEs had reference
counts that never hit zero (once linked into the internal list, each would
always have at least 1 lasting structural reference).

To fix this so it will stay standing when an "unload" function is added to
match ENGINE_load_builtin_engines(), the "constructor" functions for each
ENGINE implementation have been changed to dynamically allocate and
construct their own ENGINEs using API functions. The other benefit of this
is that no ENGINE implementation has to include the internal "engine_int.h"
header file any more.

ENGINE handler functions should take the ENGINE structure as a parameter -
this is because ENGINE structures can be copied, and like other
structure/method setups in OpenSSL, it should be possible for init(),
finish(), ctrl(), etc to adjust state inside the ENGINE structures rather
than globally. This commit includes the dependant changes in the ENGINE
implementations.

Incease the number of BIGNUMs in a BN_CTX.

sure they are available in opensslconf.h, by giving them names starting
with "OPENSSL_" to avoid conflicts with other packages and by making
sure e_os2.h will cover all platform-specific cases together with
opensslconf.h.

I've checked fairly well that nothing breaks with this (apart from
external software that will adapt if they have used something like
NO_KRB5), but I can't guarantee it completely, so a review of this
change would be a good thing.

engine structure, and some ANSI C compilers will complain otherwise.

few small constifying changes, and why not throw in a couple of extras
while I'm at it?

At the same time, add VMS support for Rijndael.