> From: owner-openssl-us...@openssl.org On Behalf Of Jeffrey Walton > Sent: Monday, 11 February, 2013 01:12
> I'm trying to memory map a file. Does OpenSSL BIO's allow this? > > I seem to be failing on BIO_read_filename with a `ret` of 0. The docs > state I should expect `ret` of 1. When I look for the problem, I'm > getting an error code of 0 (`err`, success). > (BIO_read_filename = BIO_ctrl _SET_FILENAME on a mem-BIO) That doesn't make sense. OpenSSL doesn't map a file itself; that isn't portable. If you *already* have a file mapped into memory by e.g. mmap in Unix and something different in Windows, you can create a *readonly* mem-BIO on that memory with BIO_new_mem_buf. I don't think you can do this for write; writing to a mem-BIO must be able to re-allocate the underlying buffer when it thinks necessary, and that can't work for a file mapped to a fixed area of memory. BIO_ctrl of an option inapplicable to mem-BIO returns 0 but doesn't set anything in the error queue. Yes, this isn't too helpful. > I ask because the doc's appear to be incorrect on the return type of > BIO_read_filename. When I try and use an `int`, I get a size warning > (long instead of int). So I suspect the docs may be wrong. > http://www.openssl.org/docs/crypto/BIO_s_file.html. > I suspect at some point in the distant past BIO_read_filename was a separate routine and did return int. When it was combined into the more general BIO_ctrl/file_ctrl mechanism, that handles many options some of which need to return long, and the manpage probably wasn't updated. ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager majord...@openssl.org
