1=pod 2 3=head1 NAME 4 5BIO_new_CMS - CMS streaming filter BIO 6 7=head1 SYNOPSIS 8 9 #include <openssl/cms.h> 10 11 BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms); 12 13=head1 DESCRIPTION 14 15BIO_new_CMS() returns a streaming filter BIO chain based on B<cms>. The output 16of the filter is written to B<out>. Any data written to the chain is 17automatically translated to a BER format CMS structure of the appropriate type. 18 19=head1 NOTES 20 21The chain returned by this function behaves like a standard filter BIO. It 22supports non blocking I/O. Content is processed and streamed on the fly and not 23all held in memory at once: so it is possible to encode very large structures. 24After all content has been written through the chain BIO_flush() must be called 25to finalise the structure. 26 27The B<CMS_STREAM> flag must be included in the corresponding B<flags> 28parameter of the B<cms> creation function. 29 30If an application wishes to write additional data to B<out> BIOs should be 31removed from the chain using BIO_pop() and freed with BIO_free() until B<out> 32is reached. If no additional data needs to be written BIO_free_all() can be 33called to free up the whole chain. 34 35Any content written through the filter is used verbatim: no canonical 36translation is performed. 37 38It is possible to chain multiple BIOs to, for example, create a triple wrapped 39signed, enveloped, signed structure. In this case it is the applications 40responsibility to set the inner content type of any outer CMS_ContentInfo 41structures. 42 43Large numbers of small writes through the chain should be avoided as this will 44produce an output consisting of lots of OCTET STRING structures. Prepending 45a BIO_f_buffer() buffering BIO will prevent this. 46 47=head1 BUGS 48 49There is currently no corresponding inverse BIO: i.e. one which can decode 50a CMS structure on the fly. 51 52=head1 RETURN VALUES 53 54BIO_new_CMS() returns a BIO chain when successful or NULL if an error 55occurred. The error can be obtained from ERR_get_error(3). 56 57=head1 SEE ALSO 58 59L<ERR_get_error(3)>, L<CMS_sign(3)>, 60L<CMS_encrypt(3)> 61 62=head1 HISTORY 63 64BIO_new_CMS() was added to OpenSSL 1.0.0 65 66=head1 COPYRIGHT 67 68Copyright 2008-2016 The OpenSSL Project Authors. All Rights Reserved. 69 70Licensed under the OpenSSL license (the "License"). You may not use 71this file except in compliance with the License. You can obtain a copy 72in the file LICENSE in the source distribution or at 73L<https://www.openssl.org/source/license.html>. 74 75=cut 76