mirror of
https://github.com/openssl/openssl.git
synced 2024-12-15 06:01:37 +08:00
9a4fd80ee0
The BIO_f_buffer() documentation tells in enough detail how it affects BIO_gets(), but not how it affects BIO_read_ex(). This change remedies that. Fixes #10859 Reviewed-by: Tim Hudson <tjh@openssl.org> (Merged from https://github.com/openssl/openssl/pull/10890)
103 lines
3.5 KiB
Plaintext
103 lines
3.5 KiB
Plaintext
=pod
|
|
|
|
=head1 NAME
|
|
|
|
BIO_get_buffer_num_lines,
|
|
BIO_set_read_buffer_size,
|
|
BIO_set_write_buffer_size,
|
|
BIO_set_buffer_size,
|
|
BIO_set_buffer_read_data,
|
|
BIO_f_buffer
|
|
- buffering BIO
|
|
|
|
=head1 SYNOPSIS
|
|
|
|
#include <openssl/bio.h>
|
|
|
|
const BIO_METHOD *BIO_f_buffer(void);
|
|
|
|
long BIO_get_buffer_num_lines(BIO *b);
|
|
long BIO_set_read_buffer_size(BIO *b, long size);
|
|
long BIO_set_write_buffer_size(BIO *b, long size);
|
|
long BIO_set_buffer_size(BIO *b, long size);
|
|
long BIO_set_buffer_read_data(BIO *b, void *buf, long num);
|
|
|
|
=head1 DESCRIPTION
|
|
|
|
BIO_f_buffer() returns the buffering BIO method.
|
|
|
|
Data written to a buffering BIO is buffered and periodically written
|
|
to the next BIO in the chain. Data read from a buffering BIO comes from
|
|
an internal buffer which is filled from the next BIO in the chain.
|
|
Both BIO_gets() and BIO_puts() are supported.
|
|
|
|
Calling BIO_reset() on a buffering BIO clears any buffered data.
|
|
|
|
BIO_get_buffer_num_lines() returns the number of lines currently buffered.
|
|
|
|
BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size()
|
|
set the read, write or both read and write buffer sizes to B<size>. The initial
|
|
buffer size is DEFAULT_BUFFER_SIZE, currently 4096. Any attempt to reduce the
|
|
buffer size below DEFAULT_BUFFER_SIZE is ignored. Any buffered data is cleared
|
|
when the buffer is resized.
|
|
|
|
BIO_set_buffer_read_data() clears the read buffer and fills it with B<num>
|
|
bytes of B<buf>. If B<num> is larger than the current buffer size the buffer
|
|
is expanded.
|
|
|
|
=head1 NOTES
|
|
|
|
These functions, other than BIO_f_buffer(), are implemented as macros.
|
|
|
|
Buffering BIOs implement BIO_read_ex() and BIO_gets() by using
|
|
BIO_read_ex() operations on the next 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; a BIO_gets() is guaranteed to give
|
|
the caller a whole line, and 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. By prepending a
|
|
buffering BIO to a chain it is therefore possible to provide
|
|
BIO_gets() or exact size BIO_read_ex() functionality if the following
|
|
BIOs do not support it.
|
|
|
|
Do not add more than one BIO_f_buffer() to a BIO chain. The result of
|
|
doing so will force a full read of the size of the internal buffer of
|
|
the top BIO_f_buffer(), which is 4 KiB at a minimum.
|
|
|
|
Data is only written to the next BIO in the chain when the write buffer fills
|
|
or when BIO_flush() is called. It is therefore important to call BIO_flush()
|
|
whenever any pending data should be written such as when removing a buffering
|
|
BIO using BIO_pop(). BIO_flush() may need to be retried if the ultimate
|
|
source/sink BIO is non blocking.
|
|
|
|
=head1 RETURN VALUES
|
|
|
|
BIO_f_buffer() returns the buffering BIO method.
|
|
|
|
BIO_get_buffer_num_lines() returns the number of lines buffered (may be 0).
|
|
|
|
BIO_set_read_buffer_size(), BIO_set_write_buffer_size() and BIO_set_buffer_size()
|
|
return 1 if the buffer was successfully resized or 0 for failure.
|
|
|
|
BIO_set_buffer_read_data() returns 1 if the data was set correctly or 0 if
|
|
there was an error.
|
|
|
|
=head1 SEE ALSO
|
|
|
|
L<bio(7)>,
|
|
L<BIO_reset(3)>,
|
|
L<BIO_flush(3)>,
|
|
L<BIO_pop(3)>,
|
|
L<BIO_ctrl(3)>.
|
|
|
|
=head1 COPYRIGHT
|
|
|
|
Copyright 2000-2016 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
|