NAME
BIO_get_new_index,
BIO_meth_new, BIO_meth_free,
BIO_meth_get_write,
BIO_meth_set_write,
BIO_meth_get_read,
BIO_meth_set_read,
BIO_meth_get_puts,
BIO_meth_set_puts,
BIO_meth_get_gets,
BIO_meth_set_gets,
BIO_meth_get_ctrl,
BIO_meth_set_ctrl,
BIO_meth_get_create,
BIO_meth_set_create,
BIO_meth_get_destroy,
BIO_meth_set_destroy,
BIO_meth_get_callback_ctrl,
BIO_meth_set_callback_ctrl —
manipulate BIO_METHOD
structures
SYNOPSIS
#include
<openssl/bio.h>
int
BIO_get_new_index(void);
BIO_METHOD *
BIO_meth_new(int type,
const char *name);
void
BIO_meth_free(BIO_METHOD
*biom);
int
(*BIO_meth_get_write(const BIO_METHOD
*biom))(BIO
*, const char *,
int);
int
BIO_meth_set_write(BIO_METHOD
*biom, int (*write)(BIO *, const char *,
int));
int
(*BIO_meth_get_read(const BIO_METHOD
*biom))(BIO
*, char *,
int);
int
BIO_meth_set_read(BIO_METHOD
*biom, int (*read)(BIO *, char *, int));
int
(*BIO_meth_get_puts(const BIO_METHOD
*biom))(BIO
*, const char
*);
int
BIO_meth_set_puts(BIO_METHOD
*biom, int (*puts)(BIO *, const char *));
int
(*BIO_meth_get_gets(const BIO_METHOD
*biom))(BIO
*, char *,
int);
int
BIO_meth_set_gets(BIO_METHOD
*biom, int (*gets)(BIO *, char *, int));
long
(*BIO_meth_get_ctrl(const BIO_METHOD
*biom))(BIO
*, int,
long,
void *);
int
BIO_meth_set_ctrl(BIO_METHOD
*biom, long (*ctrl)(BIO *, int, long, void
*));
int
(*BIO_meth_get_create(const BIO_METHOD
*biom))(BIO
*);
int
BIO_meth_set_create(BIO_METHOD
*biom, int (*create)(BIO *));
int
(*BIO_meth_get_destroy(const BIO_METHOD
*biom))(BIO
*);
int
BIO_meth_set_destroy(BIO_METHOD
*biom, int (*destroy)(BIO *));
long
(*BIO_meth_get_callback_ctrl(const BIO_METHOD
*biom))(BIO *, int,
BIO_info_cb *);
int
BIO_meth_set_callback_ctrl(BIO_METHOD
*biom, long (*callback_ctrl)(BIO *, int, BIO_info_cb
*));
DESCRIPTION
The BIO_METHOD structure stores function pointers implementing a BIO type. See BIO_new(3) for more information about BIO objects.
BIO_meth_new()
creates a new BIO_METHOD structure. It requires a
unique integer type; use
BIO_get_new_index()
to get the value for type. Currently, the user can
only create up to 127 different BIO types, and type is
limited to the range 129–255. The name pointer
is stored in the structure and will not be freed by
BIO_meth_free().
The standard BIO types are listed in
<openssl/bio.h>. Some
examples include BIO_TYPE_BUFFER and
BIO_TYPE_CIPHER. The type of
filter BIOs should have the BIO_TYPE_FILTER bit set.
Source/sink BIOs should have the
BIO_TYPE_SOURCE_SINK bit set. File descriptor based
BIOs (e.g. socket, fd, connect, accept etc.) should additionally have the
BIO_TYPE_DESCRIPTOR bit set. See
BIO_find_type(3) for more information.
BIO_meth_free()
is an alias for free(3).
BIO_meth_get_write(),
BIO_meth_set_write(),
BIO_meth_get_read(),
and
BIO_meth_set_read()
get and set the functions write and
read used for writing and reading arbitrary length
data to and from the BIO. These functions are called
from BIO_write(3) and
BIO_read(3), respectively. The parameters and return values of
write and read have the same
meaning as for
BIO_write(3) and
BIO_read(3).
BIO_meth_get_puts()
and
BIO_meth_set_puts()
get and set the function puts used for writing a
NUL-terminated string to the BIO. This function is
called from
BIO_puts(3). The parameters and the return value of
puts have the same meaning as for
BIO_puts(3).
BIO_meth_get_gets()
and
BIO_meth_set_gets()
get and set the function gets used for reading a line
of data from the BIO. This function is called from
BIO_gets(3). The parameters and the return value of
gets have the same meaning as for
BIO_gets(3).
BIO_meth_get_ctrl()
and
BIO_meth_set_ctrl()
get and set the function ctrl used for processing
control messages in the BIO. This function is called
from BIO_ctrl(3). The parameters and return value of
ctrl have the same meaning as for
BIO_ctrl(3).
BIO_meth_get_create()
and
BIO_meth_set_create()
get and set a function create used while initializing
a new instance of the BIO. This function is called
from BIO_new(3). The
BIO_new(3) function allocates the memory for the new
BIO, and a pointer to this newly allocated structure
is passed as the parameter to create.
BIO_meth_get_destroy()
and
BIO_meth_set_destroy()
get and set a function destroy used while destroying
an instance of a BIO. This function is called from
BIO_free(3). A pointer to the BIO to be
destroyed is passed as the parameter. The destroy
function is intended to perform clean-up specific to the
BIO type. The memory for the
BIO itself must not be freed by this function.
BIO_meth_get_callback_ctrl()
and
BIO_meth_set_callback_ctrl()
get and set the function callback_ctrl used for
processing callback control messages in the BIO. This
function is called from
BIO_callback_ctrl(3). The parameters and return value of
callback_ctrl have the same meaning as for
BIO_callback_ctrl(3).
RETURN VALUES
BIO_get_new_index() returns the new BIO
type value or -1 if an error occurs.
BIO_meth_new() returns the new
BIO_METHOD structure or NULL
if an error occurs.
The BIO_meth_set_*() functions return 1 on
success or 0 on error. Currently, they cannot fail.
The BIO_meth_get_*() functions return
function pointers.
SEE ALSO
HISTORY
These functions first appeared in OpenSSL 1.1.0 and have been available since OpenBSD 6.3.