/usr/man/cat.3/RSA_get_ex_data.3(/usr/man/cat.3/RSA_get_ex_data.3)

RSA_get_ex_new_index(3)      OpenSSL      RSA_get_ex_new_index(3)

NAME

     RSA_get_ex_new_index, RSA_set_ex_data, RSA_get_ex_data - add
     application specific data to RSA structures

SYNOPSIS

      #include <openssl/rsa.h>

      int RSA_get_ex_new_index(long argl, void *argp,
                     CRYPTO_EX_new *new_func,
                     CRYPTO_EX_dup *dup_func,
                     CRYPTO_EX_free *free_func);

      int RSA_set_ex_data(RSA *r, int idx, void *arg);

      void *RSA_get_ex_data(RSA *r, int idx);

      typedef int CRYPTO_EX_new(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
                                int idx, long argl, void *argp);
      typedef void CRYPTO_EX_free(void *parent, void *ptr, CRYPTO_EX_DATA *ad,
                                  int idx, long argl, void *argp);
      typedef int CRYPTO_EX_dup(CRYPTO_EX_DATA *to, CRYPTO_EX_DATA *from, void *from_d,
                                int idx, long argl, void *argp);

DESCRIPTION

     Several OpenSSL structures can have application specific
     data attached to them.  This has several potential uses, it
     can be used to cache data associated with a structure (for
     example the hash of some part of the structure) or some
     additional data (for example a handle to the data in an
     external library).

     Since the application data can be anything at all it is
     passed and retrieved as a void * type.

     The RRSSAA_ggeett_eexx_nneeww_iinnddeexx(()) function is initially called to
     "register" some new application specific data. It takes
     three optional function pointers which are called when the
     parent structure (in this case an RSA structure) is
     initially created, when it is copied and when it is freed
     up. If any or all of these function pointer arguments are
     not used they should be set to NULL. The precise manner in
     which these function pointers are called is described in
     more detail below. RRSSAA_ggeett_eexx_nneeww_iinnddeexx(()) also takes
     additional long and pointer parameters which will be passed
     to the supplied functions but which otherwise have no
     special meaning. It returns an index which should be stored
     (typically in a static variable) and passed used in the idx
     parameter in the remaining functions. Each successful call
     to RRSSAA_ggeett_eexx_nneeww_iinnddeexx(()) will return an index greater than
     any previously returned, this is important because the
     optional functions are called in order of increasing index
     value.

1.0.2t               Last change: 2019-09-10                    1

RSA_get_ex_new_index(3)      OpenSSL      RSA_get_ex_new_index(3)

     RRSSAA_sseett_eexx_ddaattaa(()) is used to set application specific data,
     the data is supplied in the arg parameter and its precise
     meaning is up to the application.

     RRSSAA_ggeett_eexx_ddaattaa(()) is used to retrieve application specific
     data. The data is returned to the application, this will be
     the same value as supplied to a previous RRSSAA_sseett_eexx_ddaattaa(())
     call.

     nneeww_ffuunncc(()) is called when a structure is initially allocated
     (for example with RRSSAA_nneeww(()). The parent structure members
     will not have any meaningful values at this point. This
     function will typically be used to allocate any application
     specific structure.

     ffrreeee_ffuunncc(()) is called when a structure is being freed up.
     The dynamic parent structure members should not be accessed
     because they will be freed up when this function is called.

     nneeww_ffuunncc(()) and ffrreeee_ffuunncc(()) take the same parameters. parent
     is a pointer to the parent RSA structure. ptr is a the
     application specific data (this wont be of much use in
     nneeww_ffuunncc(()). ad is a pointer to the CRYPTO_EX_DATA structure
     from the parent RSA structure: the functions
     CCRRYYPPTTOO_ggeett_eexx_ddaattaa(()) and CCRRYYPPTTOO_sseett_eexx_ddaattaa(()) can be called
     to manipulate it. The idx parameter is the index: this will
     be the same value returned by RRSSAA_ggeett_eexx_nneeww_iinnddeexx(()) when
     the functions were initially registered. Finally the argl
     and argp parameters are the values originally passed to the
     same corresponding parameters when RRSSAA_ggeett_eexx_nneeww_iinnddeexx(())
     was called.

     dduupp_ffuunncc(()) is called when a structure is being copied.
     Pointers to the destination and source CRYPTO_EX_DATA
     structures are passed in the to and from parameters
     respectively. The from_d parameter is passed a pointer to
     the source application data when the function is called,
     when the function returns the value is copied to the
     destination: the application can thus modify the data
     pointed to by from_d and have different values in the source
     and destination.  The idx, argl and argp parameters are the
     same as those in nneeww_ffuunncc(()) and ffrreeee_ffuunncc(()).

     RRSSAA_ggeett_eexx_nneeww_iinnddeexx(()) returns a new index or -1 on failure
     (note 0 is a valid index value).

     RRSSAA_sseett_eexx_ddaattaa(()) returns 1 on success or 0 on failure.

     RRSSAA_ggeett_eexx_ddaattaa(()) returns the application data or 0 on
     failure. 0 may also be valid application data but currently
     it can only fail if given an invalid idx parameter.

1.0.2t               Last change: 2019-09-10                    2

RSA_get_ex_new_index(3)      OpenSSL      RSA_get_ex_new_index(3)

     nneeww_ffuunncc(()) and dduupp_ffuunncc(()) should return 0 for failure and 1
     for success.

     On failure an error code can be obtained from
     ERR_get_error(3).

     dduupp_ffuunncc(()) is currently never called.

     The return value of nneeww_ffuunncc(()) is ignored.

     The nneeww_ffuunncc(()) function isn't very useful because no
     meaningful values are present in the parent RSA structure
     when it is called.

     rsa(3), CRYPTO_set_ex_data(3)

     RSA_get_ex_new_index(), RSA_set_ex_data() and
     RSA_get_ex_data() are available since SSLeay 0.9.0.

1.0.2t               Last change: 2019-09-10                    3

See also RSA_get_ex_new_index(3)
See also RSA_set_ex_data(3)