On Thu, Jun 13, 2002 at 01:26:42PM +0200, Bodo Moeller via RT wrote: > [[EMAIL PROTECTED] - Thu Jun 6 18:39:34 2002]: > > It appears the openssl guys goofed in 0.97beta. The prototype for the > > d2i_RSAPrivateKey function in 0.9.6c, which I use, is like this: > > > > d2i_RSAPrivateKey(RSA **a, unsigned char **pp, long length); > > > > ie., without a const on the second parameter. The const should have > > been done like this (I think): > > const unsigned char * const *pp > > ...which would be entirely backwards-compatible with old versions of > > openssl. > > Could you explain why you think this would improve compatibility > (compared with 'const unsigned char **pp', which is how 'pp' should > be declared in 0.9.7-beta1, although the exact definition is > hidden behind macros)?
Any variable that could be passed to a function taking "unsigned char **" could also be passed to a function taking "const unsigned char * const *". Thus, using the above declaration would make openssl's api 100% source-compatible with previous versions, while promising an increased level of constness. Using "const unsigned char **", however, is not 100% api-compatible, because you can't safely pass an "unsigned char **" to it, for complicated reasons explained in the URL I sent earlier. > In fact the second 'const' would be wrong because the pointer that > 'pp' points to is updated to reflect how much of the encoded data > has been processed by the d2i_... function. I.e., it is not > at all constant. Now, you caught me there. The change I proposed earlier (adding an additional "const") would fix API compatibility, but promises a level of constness that you're not actually providing. Unfortunately, I don't know a way around it: the problem is that the beta1 level of constness looks right, but doesn't _actually_ promise the constness that it looks like it does, due to the crazy hackery described in the URL I sent earlier. It also makes the API incompatible with older versions. I can't pass the address of "unsigned char *p" to the new function. On the other hand, I can't pass the address of "const unsigned char *p" to the old-style function. Neither situation is desirable... but it looks like you might have to just use two different functions with two different APIs, unfortunately. I don't know another way out. Have fun, Avery ______________________________________________________________________ OpenSSL Project http://www.openssl.org Development Mailing List [EMAIL PROTECTED] Automated List Manager [EMAIL PROTECTED]
