2000-09-07 00:22:31 +00:00
|
|
|
=pod
|
|
|
|
|
|
|
|
|
|
=head1 NAME
|
|
|
|
|
|
2016-06-06 04:43:05 +00:00
|
|
|
BIO_push, BIO_pop, BIO_set_next - add and remove BIOs from a chain
|
2000-09-07 00:22:31 +00:00
|
|
|
|
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
|
|
|
|
|
|
#include <openssl/bio.h>
|
|
|
|
|
|
2016-07-19 13:27:53 +00:00
|
|
|
BIO *BIO_push(BIO *b, BIO *append);
|
2016-03-29 13:25:23 +00:00
|
|
|
BIO *BIO_pop(BIO *b);
|
|
|
|
|
void BIO_set_next(BIO *b, BIO *next);
|
2000-09-07 00:22:31 +00:00
|
|
|
|
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
|
|
|
|
|
|
The BIO_push() function appends the BIO B<append> to B<b>, it returns
|
|
|
|
|
B<b>.
|
|
|
|
|
|
|
|
|
|
BIO_pop() removes the BIO B<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.
|
|
|
|
|
|
2016-03-29 13:25:23 +00:00
|
|
|
BIO_set_next() replaces the existing next BIO in a chain with the BIO pointed to
|
|
|
|
|
by B<next>. The new chain may include some of the same BIOs from the old chain
|
|
|
|
|
or it may be completely different.
|
|
|
|
|
|
2000-09-07 00:22:31 +00:00
|
|
|
=head1 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.
|
|
|
|
|
|
2019-02-26 05:11:10 +00:00
|
|
|
=head1 RETURN VALUES
|
|
|
|
|
|
|
|
|
|
BIO_push() returns the end of the chain, B<b>.
|
|
|
|
|
|
|
|
|
|
BIO_pop() returns the next BIO in the chain, or NULL if there is no next
|
|
|
|
|
BIO.
|
|
|
|
|
|
2000-09-07 00:22:31 +00:00
|
|
|
=head1 EXAMPLES
|
|
|
|
|
|
|
|
|
|
For these examples suppose B<md1> and B<md2> are digest BIOs, B<b64> is
|
|
|
|
|
a base64 BIO and B<f> is a file BIO.
|
|
|
|
|
|
|
|
|
|
If the call:
|
|
|
|
|
|
|
|
|
|
BIO_push(b64, f);
|
|
|
|
|
|
2014-06-29 12:38:55 +00:00
|
|
|
is made then the new chain will be B<b64-f>. After making the calls
|
2000-09-07 00:22:31 +00:00
|
|
|
|
|
|
|
|
BIO_push(md2, b64);
|
|
|
|
|
BIO_push(md1, md2);
|
|
|
|
|
|
|
|
|
|
the new chain is B<md1-md2-b64-f>. Data written to B<md1> will be digested
|
|
|
|
|
by B<md1> and B<md2>, B<base64> encoded and written to B<f>.
|
|
|
|
|
|
|
|
|
|
It should be noted that reading causes data to pass in the reverse
|
|
|
|
|
direction, that is data is read from B<f>, base64 B<decoded> and digested
|
|
|
|
|
by B<md1> and B<md2>. If the call:
|
|
|
|
|
|
|
|
|
|
BIO_pop(md2);
|
|
|
|
|
|
|
|
|
|
The call will return B<b64> and the new chain will be B<md1-b64-f> data can
|
|
|
|
|
be written to B<md1> as before.
|
|
|
|
|
|
|
|
|
|
=head1 SEE ALSO
|
|
|
|
|
|
2016-03-29 13:25:23 +00:00
|
|
|
L<bio>
|
|
|
|
|
|
|
|
|
|
=head1 HISTORY
|
|
|
|
|
|
2017-07-15 13:39:45 +00:00
|
|
|
The BIO_set_next() function was added in OpenSSL 1.1.0.
|
2016-03-29 13:25:23 +00:00
|
|
|
|
2016-05-18 15:44:05 +00:00
|
|
|
=head1 COPYRIGHT
|
|
|
|
|
|
|
|
|
|
Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
|
|
|
|
|
|
|
|
|
|
Licensed under the OpenSSL license (the "License"). You may not use
|
|
|
|
|
this file except in compliance with the License. You can obtain a copy
|
|
|
|
|
in the file LICENSE in the source distribution or at
|
|
|
|
|
L<https://www.openssl.org/source/license.html>.
|
|
|
|
|
|
|
|
|
|
=cut
|
