diff options
author | Shane Lontis <shane.lontis@oracle.com> | 2021-03-09 17:25:26 +1000 |
---|---|---|
committer | Shane Lontis <shane.lontis@oracle.com> | 2021-03-11 07:57:31 +1000 |
commit | a30823c80f8c1f4ac22fb358cab65ce4e81a5046 (patch) | |
tree | 4932e6285f6fc31b31097ce448c510d5f45530e8 /doc/man3 | |
parent | c8511e89804749e82d1212fba1dc06c86a266ee4 (diff) |
Add new filter BIO BIO_f_readbuffer()
This allows BIO_tell() and BIO_seek() to work for BIO's that do
not support these methods. The main use case for this is file/fd BIO's
that use stdin.
This works for stdin taken from input redirection (command < file),
and stdin via pipe (cat file | command).
Reviewed-by: Tomas Mraz <tomas@openssl.org>
Reviewed-by: Matt Caswell <matt@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/14407)
Diffstat (limited to 'doc/man3')
-rw-r--r-- | doc/man3/BIO_f_readbuffer.pod | 61 |
1 files changed, 61 insertions, 0 deletions
diff --git a/doc/man3/BIO_f_readbuffer.pod b/doc/man3/BIO_f_readbuffer.pod new file mode 100644 index 0000000000..35e708f9ad --- /dev/null +++ b/doc/man3/BIO_f_readbuffer.pod @@ -0,0 +1,61 @@ +=pod + +=head1 NAME + +BIO_f_readbuffer +- read only buffering BIO that supports BIO_tell() and BIO_seek() + +=head1 SYNOPSIS + + #include <openssl/bio.h> + + const BIO_METHOD *BIO_f_readbuffer(void); + +=head1 DESCRIPTION + +BIO_f_readbuffer() returns the read buffering BIO method. + +This BIO filter can be inserted on top of BIO's that do not support BIO_tell() +or BIO_seek() (e.g. A file BIO that uses stdin). + +Data read from a read buffering BIO comes from an internal buffer which is +filled from the next BIO in the chain. + +BIO_gets() is supported for read buffering BIOs. +Writing data to a read buffering BIO is not supported. + +Calling BIO_reset() on a read buffering BIO does not clear any buffered data. + +=head1 NOTES + +Read buffering BIOs implement BIO_read_ex() by using BIO_read_ex() operations +on the next BIO (e.g. a file BIO) in the chain and storing the result in an +internal buffer, from which bytes are given back to the caller as appropriate +for the call. BIO_read_ex() is guaranteed to give the caller the number of bytes +it asks for, unless there's an error or end of communication is reached in the +next BIO. The internal buffer can grow to cache the entire contents of the next +BIO in the chain. BIO_seek() uses the internal buffer, so that it can only seek +into data that is already read. + +=head1 RETURN VALUES + +BIO_f_readbuffer() returns the read buffering BIO method. + +=head1 SEE ALSO + +L<bio(7)>, +L<BIO_read(3)>, +L<BIO_gets(3)>, +L<BIO_reset(3)>, +L<BIO_ctrl(3)>. + +=head1 COPYRIGHT + +Copyright 2021 The OpenSSL Project Authors. All Rights Reserved. + +Licensed under the Apache License 2.0 (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 |