279 lines
7.4 KiB
Groff
279 lines
7.4 KiB
Groff
.\" $OpenBSD: BIO_new.3,v 1.28 2023/07/26 20:01:04 tb Exp $
|
|
.\" full merge up to:
|
|
.\" OpenSSL man3/BIO_new.pod fb46be03 Feb 26 11:51:31 2016 +0000
|
|
.\" OpenSSL man7/bio.pod 631c37be Dec 12 16:56:50 2017 +0100
|
|
.\" partial merge up to:
|
|
.\" OpenSSL man3/BIO_new.pod e9b77246 Jan 20 19:58:49 2017 +0100
|
|
.\"
|
|
.\" This file was written by Dr. Stephen Henson <steve@openssl.org>.
|
|
.\" Copyright (c) 2000, 2015, 2016 The OpenSSL Project. All rights reserved.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\"
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\"
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in
|
|
.\" the documentation and/or other materials provided with the
|
|
.\" distribution.
|
|
.\"
|
|
.\" 3. All advertising materials mentioning features or use of this
|
|
.\" software must display the following acknowledgment:
|
|
.\" "This product includes software developed by the OpenSSL Project
|
|
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
|
|
.\"
|
|
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
|
|
.\" endorse or promote products derived from this software without
|
|
.\" prior written permission. For written permission, please contact
|
|
.\" openssl-core@openssl.org.
|
|
.\"
|
|
.\" 5. Products derived from this software may not be called "OpenSSL"
|
|
.\" nor may "OpenSSL" appear in their names without prior written
|
|
.\" permission of the OpenSSL Project.
|
|
.\"
|
|
.\" 6. Redistributions of any form whatsoever must retain the following
|
|
.\" acknowledgment:
|
|
.\" "This product includes software developed by the OpenSSL Project
|
|
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
|
|
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
|
|
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
|
|
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
|
|
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
|
|
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
|
|
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
|
|
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
|
|
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
|
|
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd $Mdocdate: July 26 2023 $
|
|
.Dt BIO_NEW 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm BIO_new ,
|
|
.Nm BIO_up_ref ,
|
|
.Nm BIO_set ,
|
|
.Nm BIO_free ,
|
|
.Nm BIO_vfree ,
|
|
.Nm BIO_free_all
|
|
.Nd construct and destruct I/O abstraction objects
|
|
.Sh SYNOPSIS
|
|
.In openssl/bio.h
|
|
.Ft BIO *
|
|
.Fo BIO_new
|
|
.Fa "const BIO_METHOD *type"
|
|
.Fc
|
|
.Ft int
|
|
.Fo BIO_up_ref
|
|
.Fa "BIO *a"
|
|
.Fc
|
|
.Ft int
|
|
.Fo BIO_set
|
|
.Fa "BIO *a"
|
|
.Fa "const BIO_METHOD *type"
|
|
.Fc
|
|
.Ft int
|
|
.Fo BIO_free
|
|
.Fa "BIO *a"
|
|
.Fc
|
|
.Ft void
|
|
.Fo BIO_vfree
|
|
.Fa "BIO *a"
|
|
.Fc
|
|
.Ft void
|
|
.Fo BIO_free_all
|
|
.Fa "BIO *a"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
A
|
|
.Vt BIO
|
|
is an I/O abstraction object, hiding many of the underlying I/O
|
|
details from an application.
|
|
If an application uses BIOs for its I/O, it can transparently handle
|
|
SSL connections, unencrypted network connections, and file I/O.
|
|
.Pp
|
|
The
|
|
.Fn BIO_new
|
|
function constructs a new
|
|
.Vt BIO
|
|
using the method
|
|
.Fa type
|
|
and sets its reference count to 1.
|
|
There are two groups of BIO types, source/sink BIOs and filter BIOs.
|
|
.Pp
|
|
Source/sink BIOs provide input or consume output.
|
|
Examples include socket BIOs and file BIOs.
|
|
.Pp
|
|
Filter BIOs take data from one BIO and pass it through to another,
|
|
or to the application, forming a chain of BIOs.
|
|
The data may be left unmodified (for example by a message digest BIO)
|
|
or translated (for example by an encryption BIO).
|
|
The effect of a filter BIO may change according to the I/O operation
|
|
it is performing: for example an encryption BIO encrypts data
|
|
if it is written to and decrypts data if it is read from.
|
|
.Pp
|
|
Some BIOs (such as memory BIOs) can be used immediately after calling
|
|
.Fn BIO_new .
|
|
Others (such as file BIOs) need some additional initialization, and
|
|
utility functions exists to construct and initialize such BIOs.
|
|
.Pp
|
|
Normally the
|
|
.Fa type
|
|
argument is supplied by a function which returns a pointer to a
|
|
.Vt BIO_METHOD .
|
|
There is a naming convention for such functions:
|
|
the methods for source/sink BIOs are called
|
|
.Fn BIO_s_*
|
|
and those for filter BIOs
|
|
.Fn BIO_f_* .
|
|
.Pp
|
|
.Fn BIO_up_ref
|
|
increments the reference count of
|
|
.Fa a
|
|
by 1.
|
|
.Pp
|
|
.Fn BIO_set
|
|
is a deprecated function to initialize an unused
|
|
.Vt BIO
|
|
structure located in static memory or on the stack,
|
|
to set its method to
|
|
.Fa type ,
|
|
and to set its reference count to 1.
|
|
It must not be called on
|
|
.Vt BIO
|
|
objects created with
|
|
.Fn BIO_new ,
|
|
nor on objects that were already used.
|
|
.Pp
|
|
.Fn BIO_free
|
|
and
|
|
.Fn BIO_vfree
|
|
decrement the reference count of
|
|
.Fa a
|
|
by 1, and if the reference count reaches 0, they destruct the single
|
|
.Vt BIO
|
|
.Fa a ,
|
|
which may also have some effect on the
|
|
underlying I/O structure, for example it may close the file being
|
|
referred to under certain circumstances.
|
|
If
|
|
.Fa a
|
|
is a
|
|
.Dv NULL
|
|
pointer, no action occurs.
|
|
If
|
|
.Fn BIO_free
|
|
is called on a BIO chain, it destructs at most one BIO,
|
|
resulting in a memory leak.
|
|
.Pp
|
|
.Fn BIO_free_all
|
|
calls
|
|
.Fn BIO_free
|
|
on
|
|
.Fa a
|
|
and on all following
|
|
.Vt BIO
|
|
objects in the chain.
|
|
As soon as the reference count of a
|
|
.Vt BIO
|
|
is still non-zero after calling
|
|
.Fn BIO_free
|
|
on it, the function
|
|
.Fn BIO_free_all
|
|
returns right away and refrains from freeing the remaining
|
|
.Vt BIO
|
|
objects in the chain.
|
|
It does not halt if an error occurs
|
|
destructing an individual BIO in the chain.
|
|
If
|
|
.Fa a
|
|
is a
|
|
.Dv NULL
|
|
pointer, no action occurs.
|
|
Calling
|
|
.Fn BIO_free_all
|
|
on a single BIO has the same effect as
|
|
.Fn BIO_vfree .
|
|
.Pp
|
|
Common I/O functions are documented in
|
|
.Xr BIO_read 3 .
|
|
Forming chains is explained in
|
|
.Xr BIO_push 3 ;
|
|
inspecting them is explained in
|
|
.Xr BIO_find_type 3 .
|
|
For more details about the different kinds of BIOs, see the individual
|
|
.Vt BIO_METHOD
|
|
manual pages.
|
|
.Sh RETURN VALUES
|
|
.Fn BIO_new
|
|
returns a newly constructed
|
|
.Vt BIO
|
|
object or
|
|
.Dv NULL
|
|
on failure.
|
|
.Pp
|
|
.Fn BIO_up_ref ,
|
|
.Fn BIO_set ,
|
|
and
|
|
.Fn BIO_free
|
|
return 1 for success or 0 for failure.
|
|
.Sh EXAMPLES
|
|
Create a memory BIO:
|
|
.Pp
|
|
.Dl BIO *mem = BIO_new(BIO_s_mem());
|
|
.Sh SEE ALSO
|
|
.Xr BIO_accept 3 ,
|
|
.Xr BIO_ctrl 3 ,
|
|
.Xr BIO_dump 3 ,
|
|
.Xr BIO_dup_chain 3 ,
|
|
.Xr BIO_f_base64 3 ,
|
|
.Xr BIO_f_buffer 3 ,
|
|
.Xr BIO_f_cipher 3 ,
|
|
.Xr BIO_f_md 3 ,
|
|
.Xr BIO_f_null 3 ,
|
|
.Xr BIO_f_ssl 3 ,
|
|
.Xr BIO_find_type 3 ,
|
|
.Xr BIO_get_ex_new_index 3 ,
|
|
.Xr BIO_meth_new 3 ,
|
|
.Xr BIO_new_CMS 3 ,
|
|
.Xr BIO_printf 3 ,
|
|
.Xr BIO_push 3 ,
|
|
.Xr BIO_read 3 ,
|
|
.Xr BIO_s_accept 3 ,
|
|
.Xr BIO_s_bio 3 ,
|
|
.Xr BIO_s_connect 3 ,
|
|
.Xr BIO_s_datagram 3 ,
|
|
.Xr BIO_s_fd 3 ,
|
|
.Xr BIO_s_file 3 ,
|
|
.Xr BIO_s_mem 3 ,
|
|
.Xr BIO_s_null 3 ,
|
|
.Xr BIO_s_socket 3 ,
|
|
.Xr BIO_set_callback 3 ,
|
|
.Xr BIO_set_data 3 ,
|
|
.Xr BIO_should_retry 3 ,
|
|
.Xr BUF_MEM_new 3 ,
|
|
.Xr crypto 3
|
|
.Sh HISTORY
|
|
.Fn BIO_new ,
|
|
.Fn BIO_set ,
|
|
and
|
|
.Fn BIO_free
|
|
first appeared in SSLeay 0.6.0.
|
|
.Fn BIO_free_all
|
|
first appeared in SSLeay 0.6.6.
|
|
All these functions have been available since
|
|
.Ox 2.4 .
|
|
.Pp
|
|
.Fn BIO_vfree
|
|
first appeared in OpenSSL 0.9.6 and has been available since
|
|
.Ox 2.9 .
|
|
.Pp
|
|
.Fn BIO_up_ref
|
|
first appeared in OpenSSL 1.1.0 and has been available since
|
|
.Ox 6.3 .
|