mirror of
https://github.com/openssl/openssl.git
synced 2024-12-16 21:43:42 +08:00
67 lines
2.1 KiB
Plaintext
67 lines
2.1 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BIO_new_CMS - CMS streaming filter BIO
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/cms.h>
|
|
|
|
BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
BIO_new_CMS() returns a streaming filter BIO chain based on B<cms>. The output
|
|
of the filter is written to B<out>. Any data written to the chain is
|
|
automatically translated to a BER format CMS structure of the appropriate type.
|
|
|
|
=head1 NOTES
|
|
|
|
The chain returned by this function behaves like a standard filter BIO. It
|
|
supports non blocking I/O. Content is processed and streamed on the fly and not
|
|
all held in memory at once: so it is possible to encode very large structures.
|
|
After all content has been written through the chain BIO_flush() must be called
|
|
to finalise the structure.
|
|
|
|
The B<CMS_STREAM> flag must be included in the corresponding B<flags>
|
|
parameter of the B<cms> creation function.
|
|
|
|
If an application wishes to write additional data to B<out> BIOs should be
|
|
removed from the chain using BIO_pop() and freed with BIO_free() until B<out>
|
|
is reached. If no additional data needs to be written BIO_free_all() can be
|
|
called to free up the whole chain.
|
|
|
|
Any content written through the filter is used verbatim: no canonical
|
|
translation is performed.
|
|
|
|
It is possible to chain multiple BIOs to, for example, create a triple wrapped
|
|
signed, enveloped, signed structure. In this case it is the applications
|
|
responsibility to set the inner content type of any outer CMS_ContentInfo
|
|
structures.
|
|
|
|
Large numbers of small writes through the chain should be avoided as this will
|
|
produce an output consisting of lots of OCTET STRING structures. Prepending
|
|
a BIO_f_buffer() buffering BIO will prevent this.
|
|
|
|
=head1 BUGS
|
|
|
|
There is currently no corresponding inverse BIO: i.e. one which can decode
|
|
a CMS structure on the fly.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
BIO_new_CMS() returns a BIO chain when successful or NULL if an error
|
|
occurred. The error can be obtained from ERR_get_error(3).
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<ERR_get_error(3)|ERR_get_error(3)>, L<CMS_sign(3)|CMS_sign(3)>,
|
|
L<CMS_encrypt(3)|CMS_encrypt(3)>
|
|
|
|
=head1 HISTORY
|
|
|
|
BIO_new_CMS() was added to OpenSSL 1.0.0
|
|
|
|
=cut
|