"Fixing" private key/generating public key from incomplete private

[Dmitry Eremin-Solenikov]

Hello,

I'm looking for a way to 'fixup' the private key. For example. I load
the DSA key from PKCS#8 keyfile. It contains (in terms of gcrypt
s-exp) domain parameters (p, q, g), secret exponent (x) but no
public exponent (y). I found gcrypt_pubkey_get_sexp, but it
(currently) only works for ECC.

It there a good way to solve my problem? I was thinking about
adding an special mode to gcry_pk_genkey or about adding a
special API resembling gcrypt_pubkey_get_sexp() but working
with such (incomplete) private keys instead of contexts.

What do you think?

-- 
With best wishes
Dmitry