Index: openssl/doc/crypto/BIO_new_CMS.pod |
=================================================================== |
--- openssl/doc/crypto/BIO_new_CMS.pod (revision 0) |
+++ openssl/doc/crypto/BIO_new_CMS.pod (revision 0) |
@@ -0,0 +1,66 @@ |
+=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 |