NAME
    OSSL_PROVIDER_set_default_search_path,
    OSSL_PROVIDER_get0_default_search_path, OSSL_PROVIDER,
    OSSL_PROVIDER_load, OSSL_PROVIDER_try_load, OSSL_PROVIDER_unload,
    OSSL_PROVIDER_load_ex, OSSL_PROVIDER_try_load_ex,
    OSSL_PROVIDER_available, OSSL_PROVIDER_do_all,
    OSSL_PROVIDER_gettable_params, OSSL_PROVIDER_get_params,
    OSSL_PROVIDER_query_operation, OSSL_PROVIDER_unquery_operation,
    OSSL_PROVIDER_get0_provider_ctx, OSSL_PROVIDER_get0_dispatch,
    OSSL_PROVIDER_add_builtin, OSSL_PROVIDER_get0_name,
    OSSL_PROVIDER_get_capabilities, OSSL_PROVIDER_add_conf_parameter,
    OSSL_PROVIDER_get_conf_parameters, OSSL_PROVIDER_conf_get_bool,
    OSSL_PROVIDER_self_test - provider routines

SYNOPSIS
     #include <openssl/provider.h>

     typedef struct ossl_provider_st OSSL_PROVIDER;

     int OSSL_PROVIDER_set_default_search_path(OSSL_LIB_CTX *libctx,
                                               const char *path);
     const char *OSSL_PROVIDER_get0_default_search_path(OSSL_LIB_CTX *libctx);

     OSSL_PROVIDER *OSSL_PROVIDER_load(OSSL_LIB_CTX *libctx, const char *name);
     OSSL_PROVIDER *OSSL_PROVIDER_load_ex(OSSL_LIB_CTX *, const char *name,
                                          OSSL_PARAM *params);
     OSSL_PROVIDER *OSSL_PROVIDER_try_load(OSSL_LIB_CTX *libctx, const char *name,
                                           int retain_fallbacks);
     OSSL_PROVIDER *OSSL_PROVIDER_try_load_ex(OSSL_LIB_CTX *, const char *name,
                                              OSSL_PARAM *params,
                                              int retain_fallbacks);
     int OSSL_PROVIDER_unload(OSSL_PROVIDER *prov);
     int OSSL_PROVIDER_available(OSSL_LIB_CTX *libctx, const char *name);
     int OSSL_PROVIDER_do_all(OSSL_LIB_CTX *ctx,
                              int (*cb)(OSSL_PROVIDER *provider, void *cbdata),
                              void *cbdata);

     const OSSL_PARAM *OSSL_PROVIDER_gettable_params(OSSL_PROVIDER *prov);
     int OSSL_PROVIDER_get_params(OSSL_PROVIDER *prov, OSSL_PARAM params[]);

     const OSSL_ALGORITHM *OSSL_PROVIDER_query_operation(const OSSL_PROVIDER *prov,
                                                         int operation_id,
                                                         int *no_cache);
     void OSSL_PROVIDER_unquery_operation(const OSSL_PROVIDER *prov,
                                          int operation_id,
                                          const OSSL_ALGORITHM *algs);
     void *OSSL_PROVIDER_get0_provider_ctx(const OSSL_PROVIDER *prov);
     const OSSL_DISPATCH *OSSL_PROVIDER_get0_dispatch(const OSSL_PROVIDER *prov);

     int OSSL_PROVIDER_add_builtin(OSSL_LIB_CTX *libctx, const char *name,
                                   ossl_provider_init_fn *init_fn);

     const char *OSSL_PROVIDER_get0_name(const OSSL_PROVIDER *prov);

     int OSSL_PROVIDER_get_capabilities(const OSSL_PROVIDER *prov,
                                        const char *capability,
                                        OSSL_CALLBACK *cb,
                                        void *arg);
     int OSSL_PROVIDER_add_conf_parameter(OSSL_PROVIDER *prov, const char *name,
                                          const char *value);
     int OSSL_PROVIDER_get_conf_parameters(OSSL_PROVIDER *prov,
                                           OSSL_PARAM params[]);
     int OSSL_PROVIDER_conf_get_bool(const OSSL_PROVIDER *prov,
                                     const char *name, int defval);
     int OSSL_PROVIDER_self_test(const OSSL_PROVIDER *prov);

DESCRIPTION
    OSSL_PROVIDER is a type that holds internal information about
    implementation providers (see provider(7) for information on what a
    provider is). A provider can be built in to the application or the
    OpenSSL libraries, or can be a loadable module. The functions described
    here handle both forms.

    Some of these functions operate within a library context, please see
    OSSL_LIB_CTX(3) for further details.

  Functions
    OSSL_PROVIDER_set_default_search_path() specifies the default search
    *path* that is to be used for looking for providers in the specified
    *libctx*. If left unspecified, an environment variable and a fall back
    default value will be used instead.

    OSSL_PROVIDER_get0_default_search_path() retrieves the default search
    *path* that is to be used for looking for providers in the specified
    *libctx*. If successful returns the path or empty string; the path is
    valid until the context is released or
    OSSL_PROVIDER_set_default_search_path() is called.

    OSSL_PROVIDER_add_builtin() is used to add a built in provider to
    OSSL_PROVIDER store in the given library context, by associating a
    provider name with a provider initialization function. This name can
    then be used with OSSL_PROVIDER_load().

    OSSL_PROVIDER_load() loads and initializes a provider. This may simply
    initialize a provider that was previously added with
    OSSL_PROVIDER_add_builtin() and run its given initialization function,
    or load a provider module with the given name and run its provider entry
    point, "OSSL_provider_init". The *name* can be a path to a provider
    module, in that case the provider name as returned by
    OSSL_PROVIDER_get0_name() will be the path. Interpretation of relative
    paths is platform dependent and they are relative to the configured
    "MODULESDIR" directory or the path set in the environment variable
    OPENSSL_MODULES if set.

    OSSL_PROVIDER_try_load() functions like OSSL_PROVIDER_load(), except
    that it does not disable the fallback providers if the provider cannot
    be loaded and initialized or if *retain_fallbacks* is nonzero. If the
    provider loads successfully and *retain_fallbacks* is zero, the fallback
    providers are disabled.

    OSSL_PROVIDER_load_ex() and OSSL_PROVIDER_try_load_ex() are the variants
    of the previous functions accepting an "OSSL_PARAM" array of the
    parameters that are passed as the configuration of the loaded provider.
    The parameters of any type but "OSSL_PARAM_UTF8_STRING" are silently
    ignored. If the parameters are provided, they replace all the ones
    specified in the configuration file.

    OSSL_PROVIDER_unload() unloads the given provider. For a provider added
    with OSSL_PROVIDER_add_builtin(), this simply runs its teardown
    function.

    OSSL_PROVIDER_available() checks if a named provider is available for
    use.

    OSSL_PROVIDER_do_all() iterates over all loaded providers, calling *cb*
    for each one, with the current provider in *provider* and the *cbdata*
    that comes from the caller. If no other provider has been loaded before
    calling this function, the default provider is still available as
    fallback. See OSSL_PROVIDER-default(7) for more information on this
    fallback behaviour.

    OSSL_PROVIDER_gettable_params() is used to get a provider parameter
    descriptor set as a constant OSSL_PARAM(3) array.

    OSSL_PROVIDER_get_params() is used to get provider parameter values. The
    caller must prepare the OSSL_PARAM(3) array before calling this
    function, and the variables acting as buffers for this parameter array
    should be filled with data when it returns successfully.

    OSSL_PROVIDER_add_conf_parameter() sets the provider configuration
    parameter *name* to *value*. Provider configuration parameters are
    managed by the OpenSSL core and normally set in the configuration file,
    but can also be set early in the main program before a provider is in
    use by multiple threads. Parameters that only affect provider
    initialisation must, for now, be set in the configuration file, only
    parameters that are also queried later have any affect when set via this
    interface. Only text parameters can be given, and it's up to the
    provider to interpret them.

    OSSL_PROVIDER_get_conf_parameters() retrieves global configuration
    parameters associated with *prov*. These configuration parameters are
    stored for each provider by the OpenSSL core, not the provider itself,
    parameters managed by the provider are queried via
    OSSL_PROVIDER_get_params() described above. The parameters are returned
    by reference, not as copies, and so the elements of the *param* array
    must have OSSL_PARAM_UTF8_PTR as their data_type.

    OSSL_PROVIDER_conf_get_bool() parses the global configuration parameter
    *name* associated with provider *prov* as a boolean value, returning a
    default value *defval* when unable to retrieve or parse the parameter.
    Parameter values equal (case-insensitively) to 1, "on", "yes", or "true"
    yield a true (nonzero) result. Parameter values equal
    (case-insensitively) to 0, "off", "no", or "false" yield a false (zero)
    result.

    OSSL_PROVIDER_self_test() is used to run a provider's self tests on
    demand. If the self tests fail then the provider will fail to provide
    any further services and algorithms. OSSL_SELF_TEST_set_callback(3) may
    be called beforehand in order to display diagnostics for the running
    self tests.

    OSSL_PROVIDER_query_operation() calls the provider's *query_operation*
    function (see provider(7)), if the provider has one. It returns an array
    of *OSSL_ALGORITHM* for the given *operation_id* terminated by an all
    NULL OSSL_ALGORITHM entry. This is considered a low-level function that
    most applications should not need to call.

    OSSL_PROVIDER_unquery_operation() calls the provider's
    *unquery_operation* function (see provider(7)), if the provider has one.
    This is considered a low-level function that most applications should
    not need to call.

    OSSL_PROVIDER_get0_provider_ctx() returns the provider context for the
    given provider. The provider context is an opaque handle set by the
    provider itself and is passed back to the provider by libcrypto in
    various function calls.

    OSSL_PROVIDER_get0_dispatch() returns the provider's dispatch table as
    it was returned in the *out* parameter from the provider's init
    function. See provider-base(7).

    If it is permissible to cache references to this array then **no_store*
    is set to 0 or 1 otherwise. If the array is not cacheable then it is
    assumed to have a short lifetime.

    OSSL_PROVIDER_get0_name() returns the name of the given provider.

    OSSL_PROVIDER_get_capabilities() provides information about the
    capabilities supported by the provider specified in *prov* with the
    capability name *capability*. For each capability of that name supported
    by the provider it will call the callback *cb* and supply a set of
    OSSL_PARAM(3)s describing the capability. It will also pass back the
    argument *arg*. For more details about capabilities and what they can be
    used for please see "CAPABILITIES" in provider-base(7).

RETURN VALUES
    OSSL_PROVIDER_set_default_search_path(), OSSL_PROVIDER_add(),
    OSSL_PROVIDER_unload(), OSSL_PROVIDER_get_params(),
    OSSL_PROVIDER_add_conf_parameter(), OSSL_PROVIDER_get_conf_parameters()
    and OSSL_PROVIDER_get_capabilities() return 1 on success, or 0 on error.

    OSSL_PROVIDER_get0_default_search_path() returns a pointer to a path on
    success, or NULL on error or if the path has not previously been set.

    OSSL_PROVIDER_load() and OSSL_PROVIDER_try_load() return a pointer to a
    provider object on success, or NULL on error.

    OSSL_PROVIDER_do_all() returns 1 if the callback *cb* returns 1 for
    every provider it is called with, or 0 if any provider callback
    invocation returns 0; callback processing stops at the first callback
    invocation on a provider that returns 0.

    OSSL_PROVIDER_available() returns 1 if the named provider is available,
    otherwise 0.

    OSSL_PROVIDER_gettable_params() returns a pointer to an array of
    constant OSSL_PARAM(3), or NULL if none is provided.

    OSSL_PROVIDER_get_params() and returns 1 on success, or 0 on error.

    OSSL_PROVIDER_query_operation() returns an array of OSSL_ALGORITHM or
    NULL on error.

    OSSL_PROVIDER_self_test() returns 1 if the self tests pass, or 0 on
    error.

EXAMPLES
    This demonstrates how to load the provider module "foo" and ask for its
    build information.

     #include <openssl/params.h>
     #include <openssl/provider.h>
     #include <openssl/err.h>

     OSSL_PROVIDER *prov = NULL;
     const char *build = NULL;
     OSSL_PARAM request[] = {
         { "buildinfo", OSSL_PARAM_UTF8_PTR, &build, 0, 0 },
         { NULL, 0, NULL, 0, 0 }
     };

     if ((prov = OSSL_PROVIDER_load(NULL, "foo")) != NULL
         && OSSL_PROVIDER_get_params(prov, request))
         printf("Provider 'foo' buildinfo: %s\n", build);
     else
         ERR_print_errors_fp(stderr);

SEE ALSO
    openssl-core.h(7), OSSL_LIB_CTX(3), provider(7)

HISTORY
    The type and functions described here were added in OpenSSL 3.0.

    The *OSSL_PROVIDER_load_ex* and *OSSL_PROVIDER_try_load_ex* functions
    were added in OpenSSL 3.2.

    The *OSSL_PROVIDER_add_conf_parameter*,
    *OSSL_PROVIDER_get_conf_parameters*, and *OSSL_PROVIDER_conf_get_bool*
    functions were added in OpenSSL 3.5.

COPYRIGHT
    Copyright 2019-2025 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>.

