BIO_find

NAME

BIO_find_type, BIO_next — BIO chain traversal

Synopsis

#include <openssl/bio.h>
BIO
*	BIO_find_type(BIO *b,int bio_type); 
BIO *	BIO_next(BIO
*b); 
#define BIO_method_type(b)	((b)->method->type) 
#define
BIO_TYPE_NONE	0 
#define BIO_TYPE_MEM	(1|0x0400) 
#define
BIO_TYPE_FILE	(2|0x0400) 
#define BIO_TYPE_FD	(4|0x0400|0x0100) 
#define
BIO_TYPE_SOCKET	(5|0x0400|0x0100) 
#define
BIO_TYPE_NULL	(6|0x0400) 
#define BIO_TYPE_SSL	(7|0x0200) 
#define
BIO_TYPE_MD	(8|0x0200) 
#define BIO_TYPE_BUFFER	(9|0x0200) 
#define
BIO_TYPE_CIPHER	(10|0x0200) 
#define BIO_TYPE_BASE64	(11|0x0200) 
#define
BIO_TYPE_CONNECT	(12|0x0400|0x0100) 
#define
BIO_TYPE_ACCEPT	(13|0x0400|0x0100) 
#define
BIO_TYPE_PROXY_CLIENT	(14|0x0200) 
#define BIO_TYPE_PROXY_SERVER	(15|0x0200) 
#define
BIO_TYPE_NBIO_TEST	(16|0x0200) 
#define BIO_TYPE_NULL_FILTER	(17|0x0200) 
#define
BIO_TYPE_BER	(18|0x0200) 
#define BIO_TYPE_BIO	(19|0x0400) 
#define
BIO_TYPE_DESCRIPTOR	0x0100 
#define BIO_TYPE_FILTER	0x0200 
#define
BIO_TYPE_SOURCE_SINK	0x0400

DESCRIPTION

The BIO_find_type() searches for a BIO of a given type in a chain, starting at BIO b. If type is a specific type (such as BIO_TYPE_MEM) then a search is made for a BIO of that type. If type is a general type (such as BIO_TYPE_SOURCE_SINK) then the next matching BIO of the given general type is searched for. BIO_find_type() returns the next matching BIO or NULL if none is found.

Note: not all the BIO_TYPE_* types above have corresponding BIO implementations.

BIO_next() returns the next BIO in a chain. It can be used to traverse all BIOs in a chain or used in conjunction with BIO_find_type() to find all BIOs of a certain type.

BIO_method_type() returns the type of a BIO.

RETURN VALUES

BIO_find_type() returns a matching BIO or NULL for no match.

BIO_next() returns the next BIO in a chain.

BIO_method_type() returns the type of the BIO b.

NOTES

BIO_next() was added to OpenSSL 0.9.6 to provide a 'clean' way to traverse a BIO chain or find multiple matches using BIO_find_type(). Previous versions had to use:

next = bio->next_bio;

Restrictions

BIO_find_type() in OpenSSL 0.9.5a and earlier could not be safely passed a NULL pointer for the b argument.

EXAMPLE

Traverse a chain looking for digest BIOs:

 BIO *btmp;
 btmp = in_bio;	/* in_bio is chain to search through */
 
 do {
 	btmp = BIO_find_type(btmp, BIO_TYPE_MD);
	if(btmp == NULL) break;	/* Not found */
	/* btmp is a digest BIO, do something with it ...*/
   	...
 
	btmp = BIO_next(btmp);
 } while(btmp);

BIO_find_type

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