"Fossies" - the Fresh Open Source Software Archive

Member "openssl-1.0.2q/doc/crypto/BIO_find_type.pod" (20 Nov 2018, 2648 Bytes) of package /linux/misc/openssl-1.0.2q.tar.gz:

Caution: As a special service "Fossies" has tried to format the requested pod source page into HTML format but links to other pod pages may be missing or even errorneous. Alternatively you can here view or download the uninterpreted pod source code. A member file download can also be achieved by clicking within a package contents listing on the according byte size field. See also the last Fossies "Diffs" side-by-side code changes report for "BIO_find_type.pod": 1.1.0g_vs_1.1.1-pre2.


BIO_find_type, BIO_next, BIO_method_type - BIO chain traversal


 #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


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.


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.


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;


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


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);