Provided by: libssl-doc_3.0.8-1ubuntu1_all bug

NAME

       OSSL_STORE_LOADER, OSSL_STORE_LOADER_fetch, OSSL_STORE_LOADER_up_ref,
       OSSL_STORE_LOADER_free, OSSL_STORE_LOADER_get0_provider,
       OSSL_STORE_LOADER_get0_properties, OSSL_STORE_LOADER_is_a,
       OSSL_STORE_LOADER_get0_description, OSSL_STORE_LOADER_do_all_provided,
       OSSL_STORE_LOADER_names_do_all, OSSL_STORE_LOADER_CTX, OSSL_STORE_LOADER_new,
       OSSL_STORE_LOADER_get0_engine, OSSL_STORE_LOADER_get0_scheme, OSSL_STORE_LOADER_set_open,
       OSSL_STORE_LOADER_set_open_ex, OSSL_STORE_LOADER_set_attach, OSSL_STORE_LOADER_set_ctrl,
       OSSL_STORE_LOADER_set_expect, OSSL_STORE_LOADER_set_find, OSSL_STORE_LOADER_set_load,
       OSSL_STORE_LOADER_set_eof, OSSL_STORE_LOADER_set_error, OSSL_STORE_LOADER_set_close,
       OSSL_STORE_register_loader, OSSL_STORE_unregister_loader, OSSL_STORE_open_fn,
       OSSL_STORE_open_ex_fn, OSSL_STORE_attach_fn, OSSL_STORE_ctrl_fn, OSSL_STORE_expect_fn,
       OSSL_STORE_find_fn, OSSL_STORE_load_fn, OSSL_STORE_eof_fn, OSSL_STORE_error_fn,
       OSSL_STORE_close_fn - Types and functions to manipulate, register and unregister STORE
       loaders for different URI schemes

SYNOPSIS

        #include <openssl/store.h>

        typedef struct ossl_store_loader_st OSSL_STORE_LOADER;

        OSSL_STORE_LOADER *OSSL_STORE_LOADER_fetch(OSSL_LIB_CTX *libctx,
                                                   const char *scheme,
                                                   const char *properties);
        int OSSL_STORE_LOADER_up_ref(OSSL_STORE_LOADER *loader);
        void OSSL_STORE_LOADER_free(OSSL_STORE_LOADER *loader);
        const OSSL_PROVIDER *OSSL_STORE_LOADER_get0_provider(const OSSL_STORE_LOADER *
                                                        loader);
        const char *OSSL_STORE_LOADER_get0_properties(const OSSL_STORE_LOADER *loader);
        const char *OSSL_STORE_LOADER_get0_description(const OSSL_STORE_LOADER *loader);
        int OSSL_STORE_LOADER_is_a(const OSSL_STORE_LOADER *loader,
                                   const char *scheme);
        void OSSL_STORE_LOADER_do_all_provided(OSSL_LIB_CTX *libctx,
                                               void (*user_fn)(OSSL_STORE_LOADER *loader,
                                                          void *arg),
                                               void *user_arg);
        int OSSL_STORE_LOADER_names_do_all(const OSSL_STORE_LOADER *loader,
                                           void (*fn)(const char *name, void *data),
                                           void *data);

       The following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely
       by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7):

        OSSL_STORE_LOADER *OSSL_STORE_LOADER_new(ENGINE *e, const char *scheme);
        const ENGINE *OSSL_STORE_LOADER_get0_engine(const OSSL_STORE_LOADER
                                                    *store_loader);
        const char *OSSL_STORE_LOADER_get0_scheme(const OSSL_STORE_LOADER
                                                  *store_loader);

        /* struct ossl_store_loader_ctx_st is defined differently by each loader */
        typedef struct ossl_store_loader_ctx_st OSSL_STORE_LOADER_CTX;

        typedef OSSL_STORE_LOADER_CTX *(*OSSL_STORE_open_fn)(
            const char *uri, const UI_METHOD *ui_method, void *ui_data);
        int OSSL_STORE_LOADER_set_open(OSSL_STORE_LOADER *store_loader,
                                       OSSL_STORE_open_fn store_open_function);
        typedef OSSL_STORE_LOADER_CTX *(*OSSL_STORE_open_ex_fn)(
            const char *uri, const UI_METHOD *ui_method, void *ui_data);
        int OSSL_STORE_LOADER_set_open_ex
            (OSSL_STORE_LOADER *store_loader,
             OSSL_STORE_open_ex_fn store_open_ex_function);
        typedef OSSL_STORE_LOADER_CTX *(*OSSL_STORE_attach_fn)
            (const OSSL_STORE_LOADER *loader, BIO *bio,
             OSSL_LIB_CTX *libctx, const char *propq,
             const UI_METHOD *ui_method, void *ui_data);
        int OSSL_STORE_LOADER_set_attach(OSSL_STORE_LOADER *loader,
                                         OSSL_STORE_attach_fn attach_function);
        typedef int (*OSSL_STORE_ctrl_fn)(OSSL_STORE_LOADER_CTX *ctx, int cmd,
                                          va_list args);
        int OSSL_STORE_LOADER_set_ctrl(OSSL_STORE_LOADER *store_loader,
                                       OSSL_STORE_ctrl_fn store_ctrl_function);
        typedef int (*OSSL_STORE_expect_fn)(OSSL_STORE_LOADER_CTX *ctx, int expected);
        int OSSL_STORE_LOADER_set_expect(OSSL_STORE_LOADER *loader,
                                         OSSL_STORE_expect_fn expect_function);
        typedef int (*OSSL_STORE_find_fn)(OSSL_STORE_LOADER_CTX *ctx,
                                          OSSL_STORE_SEARCH *criteria);
        int OSSL_STORE_LOADER_set_find(OSSL_STORE_LOADER *loader,
                                       OSSL_STORE_find_fn find_function);
        typedef OSSL_STORE_INFO *(*OSSL_STORE_load_fn)(OSSL_STORE_LOADER_CTX *ctx,
                                                       UI_METHOD *ui_method,
                                                       void *ui_data);
        int OSSL_STORE_LOADER_set_load(OSSL_STORE_LOADER *store_loader,
                                       OSSL_STORE_load_fn store_load_function);
        typedef int (*OSSL_STORE_eof_fn)(OSSL_STORE_LOADER_CTX *ctx);
        int OSSL_STORE_LOADER_set_eof(OSSL_STORE_LOADER *store_loader,
                                      OSSL_STORE_eof_fn store_eof_function);
        typedef int (*OSSL_STORE_error_fn)(OSSL_STORE_LOADER_CTX *ctx);
        int OSSL_STORE_LOADER_set_error(OSSL_STORE_LOADER *store_loader,
                                        OSSL_STORE_error_fn store_error_function);
        typedef int (*OSSL_STORE_close_fn)(OSSL_STORE_LOADER_CTX *ctx);
        int OSSL_STORE_LOADER_set_close(OSSL_STORE_LOADER *store_loader,
                                        OSSL_STORE_close_fn store_close_function);
        void OSSL_STORE_LOADER_free(OSSL_STORE_LOADER *store_loader);

        int OSSL_STORE_register_loader(OSSL_STORE_LOADER *loader);
        OSSL_STORE_LOADER *OSSL_STORE_unregister_loader(const char *scheme);

DESCRIPTION

       OSSL_STORE_LOADER is a method for OSSL_STORE loaders, which implement OSSL_STORE_open(),
       OSSL_STORE_open_ex(), OSSL_STORE_load(), OSSL_STORE_eof(), OSSL_STORE_error() and
       OSSL_STORE_close() for specific storage schemes.

       OSSL_STORE_LOADER_fetch() looks for an implementation for a storage scheme within the
       providers that has been loaded into the OSSL_LIB_CTX given by libctx, and with the
       properties given by properties.

       OSSL_STORE_LOADER_up_ref() increments the reference count for the given loader.

       OSSL_STORE_LOADER_free() decrements the reference count for the given loader, and when the
       count reaches zero, frees it.

       OSSL_STORE_LOADER_get0_provider() returns the provider of the given loader.

       OSSL_STORE_LOADER_get0_properties() returns the property definition associated with the
       given loader.

       OSSL_STORE_LOADER_is_a() checks if loader is an implementation of an algorithm that's
       identifiable with scheme.

       OSSL_STORE_LOADER_get0_description() returns a description of the loader, meant for
       display and human consumption.  The description is at the discretion of the loader
       implementation.

       OSSL_STORE_LOADER_do_all_provided() traverses all store implementations by all activated
       providers in the library context libctx, and for each of the implementations, calls
       user_fn with the implementation method and user_arg as arguments.

       OSSL_STORE_LOADER_names_do_all() traverses all names for the given loader, and calls fn
       with each name and data.

   Legacy Types and Functions (deprecated)
       These functions help applications and engines to create loaders for schemes they support.
       These are all deprecated and discouraged in favour of provider implementations, see
       provider-storemgmt(7).

       OSSL_STORE_LOADER_CTX is a type template, to be defined by each loader using "struct
       ossl_store_loader_ctx_st { ... }".

       OSSL_STORE_open_fn, OSSL_STORE_open_ex_fn, OSSL_STORE_ctrl_fn, OSSL_STORE_expect_fn,
       OSSL_STORE_find_fn, OSSL_STORE_load_fn, OSSL_STORE_eof_fn, and OSSL_STORE_close_fn are the
       function pointer types used within a STORE loader.  The functions pointed at define the
       functionality of the given loader.

       OSSL_STORE_open_fn and OSSL_STORE_open_ex_fn
           OSSL_STORE_open_ex_fn takes a URI and is expected to interpret it in the best manner
           possible according to the scheme the loader implements.  It also takes a UI_METHOD and
           associated data, to be used any time something needs to be prompted for, as well as a
           library context libctx with an associated property query propq, to be used when
           fetching necessary algorithms to perform the loads.  Furthermore, this function is
           expected to initialize what needs to be initialized, to create a private data store
           (OSSL_STORE_LOADER_CTX, see above), and to return it.  If something goes wrong, this
           function is expected to return NULL.

           OSSL_STORE_open_fn does the same thing as OSSL_STORE_open_ex_fn but uses NULL for the
           library context libctx and property query propq.

       OSSL_STORE_attach_fn
           This function takes a BIO, otherwise works like OSSL_STORE_open_ex_fn.

       OSSL_STORE_ctrl_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer, a command number cmd and a
           va_list args and is used to manipulate loader specific parameters.

           Loader specific command numbers must begin at OSSL_STORE_C_CUSTOM_START.  Any number
           below that is reserved for future globally known command numbers.

           This function is expected to return 1 on success, 0 on error.

       OSSL_STORE_expect_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and a OSSL_STORE_INFO identity
           expected, and is used to tell the loader what object type is expected.  expected may
           be zero to signify that no specific object type is expected.

           This function is expected to return 1 on success, 0 on error.

       OSSL_STORE_find_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and a OSSL_STORE_SEARCH search
           criterion, and is used to tell the loader what to search for.

           When called with the loader context being NULL, this function is expected to return 1
           if the loader supports the criterion, otherwise 0.

           When called with the loader context being something other than NULL, this function is
           expected to return 1 on success, 0 on error.

       OSSL_STORE_load_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and a UI_METHOD with associated
           data.  It's expected to load the next available data, mold it into a data structure
           that can be wrapped in a OSSL_STORE_INFO using one of the OSSL_STORE_INFO(3)
           functions.  If no more data is available or an error occurs, this function is expected
           to return NULL.  The OSSL_STORE_eof_fn and OSSL_STORE_error_fn functions must indicate
           if it was in fact the end of data or if an error occurred.

           Note that this function retrieves one data item only.

       OSSL_STORE_eof_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and is expected to return 1 to
           indicate that the end of available data has been reached.  It is otherwise expected to
           return 0.

       OSSL_STORE_error_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and is expected to return 1 to
           indicate that an error occurred in a previous call to the OSSL_STORE_load_fn function.
           It is otherwise expected to return 0.

       OSSL_STORE_close_fn
           This function takes a OSSL_STORE_LOADER_CTX pointer and is expected to close or shut
           down what needs to be closed, and finally free the contents of the
           OSSL_STORE_LOADER_CTX pointer.  It returns 1 on success and 0 on error.

       OSSL_STORE_LOADER_new() creates a new OSSL_STORE_LOADER.  It takes an ENGINE e and a
       string scheme.  scheme must always be set.  Both e and scheme are used as is and must
       therefore be alive as long as the created loader is.

       OSSL_STORE_LOADER_get0_engine() returns the engine of the store_loader.
       OSSL_STORE_LOADER_get0_scheme() returns the scheme of the store_loader.

       OSSL_STORE_LOADER_set_open() sets the opener function for the store_loader.

       OSSL_STORE_LOADER_set_open_ex() sets the opener with library context function for the
       store_loader.

       OSSL_STORE_LOADER_set_attach() sets the attacher function for the store_loader.

       OSSL_STORE_LOADER_set_ctrl() sets the control function for the store_loader.

       OSSL_STORE_LOADER_set_expect() sets the expect function for the store_loader.

       OSSL_STORE_LOADER_set_load() sets the loader function for the store_loader.

       OSSL_STORE_LOADER_set_eof() sets the end of file checker function for the store_loader.

       OSSL_STORE_LOADER_set_close() sets the closing function for the store_loader.

       OSSL_STORE_LOADER_free() frees the given store_loader.

       OSSL_STORE_register_loader() register the given store_loader and thereby makes it
       available for use with OSSL_STORE_open(), OSSL_STORE_open_ex(), OSSL_STORE_load(),
       OSSL_STORE_eof() and OSSL_STORE_close().

       OSSL_STORE_unregister_loader() unregister the store loader for the given scheme.

RETURN VALUES

       OSSL_STORE_LOADER_fetch() returns a pointer to an OSSL_STORE_LOADER object, or NULL on
       error.

       OSSL_STORE_LOADER_up_ref() returns 1 on success, or 0 on error.

       OSSL_STORE_LOADER_names_do_all() returns 1 if the callback was called for all names. A
       return value of 0 means that the callback was not called for any names.

       OSSL_STORE_LOADER_free() doesn't return any value.

       OSSL_STORE_LOADER_get0_provider() returns a pointer to a provider object, or NULL on
       error.

       OSSL_STORE_LOADER_get0_properties() returns a pointer to a property definition string, or
       NULL on error.

       OSSL_STORE_LOADER_is_a() returns 1 if loader was identifiable, otherwise 0.

       OSSL_STORE_LOADER_get0_description() returns a pointer to a decription, or NULL if there
       isn't one.

       The functions with the types OSSL_STORE_open_fn, OSSL_STORE_open_ex_fn,
       OSSL_STORE_ctrl_fn, OSSL_STORE_expect_fn, OSSL_STORE_load_fn, OSSL_STORE_eof_fn and
       OSSL_STORE_close_fn have the same return values as OSSL_STORE_open(),
       OSSL_STORE_open_ex(), OSSL_STORE_ctrl(), OSSL_STORE_expect(), OSSL_STORE_load(),
       OSSL_STORE_eof() and OSSL_STORE_close(), respectively.

       OSSL_STORE_LOADER_new() returns a pointer to a OSSL_STORE_LOADER on success, or NULL on
       failure.

       OSSL_STORE_LOADER_set_open(), OSSL_STORE_LOADER_set_open_ex(),
       OSSL_STORE_LOADER_set_ctrl(), OSSL_STORE_LOADER_set_load(), OSSL_STORE_LOADER_set_eof()
       and OSSL_STORE_LOADER_set_close() return 1 on success, or 0 on failure.

       OSSL_STORE_register_loader() returns 1 on success, or 0 on failure.

       OSSL_STORE_unregister_loader() returns the unregistered loader on success, or NULL on
       failure.

SEE ALSO

       ossl_store(7), OSSL_STORE_open(3), OSSL_LIB_CTX(3), provider-storemgmt(7)

HISTORY

       OSSL_STORE_LOADER_fetch(), OSSL_STORE_LOADER_up_ref(), OSSL_STORE_LOADER_free(),
       OSSL_STORE_LOADER_get0_provider(), OSSL_STORE_LOADER_get0_properties(),
       OSSL_STORE_LOADER_is_a(), OSSL_STORE_LOADER_do_all_provided() and
       OSSL_STORE_LOADER_names_do_all() were added in OpenSSL 3.0.

       OSSL_STORE_open_ex_fn() was added in OpenSSL 3.0.

       OSSL_STORE_LOADER, OSSL_STORE_LOADER_CTX, OSSL_STORE_LOADER_new(),
       OSSL_STORE_LOADER_set0_scheme(), OSSL_STORE_LOADER_get0_scheme(),
       OSSL_STORE_LOADER_get0_engine(), OSSL_STORE_LOADER_set_expect(),
       OSSL_STORE_LOADER_set_find(), OSSL_STORE_LOADER_set_attach(),
       OSSL_STORE_LOADER_set_open_ex(), OSSL_STORE_LOADER_set_open(),
       OSSL_STORE_LOADER_set_ctrl(), OSSL_STORE_LOADER_set_load(), OSSL_STORE_LOADER_set_eof(),
       OSSL_STORE_LOADER_set_close(), OSSL_STORE_LOADER_free(), OSSL_STORE_register_loader(),
       OSSL_STORE_LOADER_set_error(), OSSL_STORE_unregister_loader(), OSSL_STORE_open_fn(),
       OSSL_STORE_ctrl_fn(), OSSL_STORE_load_fn(), OSSL_STORE_eof_fn() and OSSL_STORE_close_fn()
       were added in OpenSSL 1.1.1, and became deprecated in OpenSSL 3.0.

COPYRIGHT

       Copyright 2016-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.