bio_new_cms(3ssl) [linux man page]

BIO_new_CMS(3SSL)						      OpenSSL							 BIO_new_CMS(3SSL)

NAME

	BIO_new_CMS - CMS streaming filter BIO

SYNOPSIS

	#include <openssl/cms.h>

	BIO *BIO_new_CMS(BIO *out, CMS_ContentInfo *cms);

DESCRIPTION

       BIO_new_CMS() returns a streaming filter BIO chain based on cms. The output of the filter is written to out. Any data written to the chain
       is automatically translated to a BER format CMS structure of the appropriate type.

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 CMS_STREAM flag must be included in the corresponding flags parameter of the cms creation function.

       If an application wishes to write additional data to out BIOs should be removed from the chain using BIO_pop() and freed with BIO_free()
       until 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.

BUGS

       There is currently no corresponding inverse BIO: i.e. one which can decode a CMS structure on the fly.

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).

SEE ALSO

       ERR_get_error(3), CMS_sign(3), CMS_encrypt(3)

HISTORY

       BIO_new_CMS() was added to OpenSSL 1.0.0

1.0.0e								    2009-09-30							 BIO_new_CMS(3SSL)

BIO_push(3SSL)                                                        OpenSSL                                                       BIO_push(3SSL)

NAME

       BIO_push, BIO_pop - add and remove BIOs from a chain.

SYNOPSIS

        #include <openssl/bio.h>

        BIO *  BIO_push(BIO *b,BIO *append);
        BIO *  BIO_pop(BIO *b);

DESCRIPTION

       The BIO_push() function appends the BIO append to b, it returns b.

       BIO_pop() removes the BIO b from a chain and returns the next BIO in the chain, or NULL if there is no next BIO. The removed BIO then
       becomes a single BIO with no association with the original chain, it can thus be freed or attached to a different chain.

NOTES

       The names of these functions are perhaps a little misleading. BIO_push() joins two BIO chains whereas BIO_pop() deletes a single BIO from a
       chain, the deleted BIO does not need to be at the end of a chain.

       The process of calling BIO_push() and BIO_pop() on a BIO may have additional consequences (a control call is made to the affected BIOs) any
       effects will be noted in the descriptions of individual BIOs.

EXAMPLES

       For these examples suppose md1 and md2 are digest BIOs, b64 is a base64 BIO and f is a file BIO.

       If the call:

        BIO_push(b64, f);

       is made then the new chain will be b64-chain. After making the calls

        BIO_push(md2, b64);
        BIO_push(md1, md2);

       the new chain is md1-md2-b64-f. Data written to md1 will be digested by md1 and md2, base64 encoded and written to f.

       It should be noted that reading causes data to pass in the reverse direction, that is data is read from f, base64 decoded and digested by
       md1 and md2. If the call:

        BIO_pop(md2);

       The call will return b64 and the new chain will be md1-b64-f data can be written to md1 as before.

RETURN VALUES

       BIO_push() returns the end of the chain, b.

       BIO_pop() returns the next BIO in the chain, or NULL if there is no next BIO.

SEE ALSO

       TBA

1.0.1e                                                              2013-02-11                                                      BIO_push(3SSL)