This is a small patch (against master) to allow an application using libpq with GSSAPI authentication to specify where to fetch the credential cache from -- it effectively consists of a new field in PQconninfoOptions to store this data and (where the user has specified a ccache location) a call into the gss_krb5_ccache_name function in the GSSAPI library.
The pgAdmin team would love to have this feature. It would greatly simplify management of multiple connections from different users.
It's my first go at submitting a patch -- it works as far as I can tell, but I suspect there will probably still be stuff to fix before it's ready to use!
As far as I'm concerned this is working (the code compiles successfully following "./configure --with-gssapi --enable-cassert", and seems to work for specifying the ccache location without any noticeable errors).
I hope there shouldn't be anything platform-specific here (I've been working on Ubuntu Linux but the only interactions with external applications are via the GSSAPI library, which was already in use).
The dispsize value for ccache_name is 64 in this code (which seems to be what's used with other file-path-like parameters in the existing code) but I'm happy to have this corrected if it needs a different value -- as far as I can tell this is just for display purposes rather than anything critical in terms of actually storing the value?
If no ccache_name is specified in the connection string then it defaults to NULL, which means the gss_krb5_ccache_name call is not made and the current behaviour (of letting the GSSAPI library work out the location of the ccache) is not changed.
