=pod =head1 NAME OSSL_PROVIDER, OSSL_PROVIDER_load, OSSL_PROVIDER_unload, OSSL_PROVIDER_get_param_types, OSSL_PROVIDER_get_params, OSSL_PROVIDER_add_builtin - provider routines =head1 SYNOPSIS #include typedef struct ossl_provider_st OSSL_PROVIDER; OSSL_PROVIDER *OSSL_PROVIDER_load(OPENSSL_CTX *, const char *name); int OSSL_PROVIDER_unload(OSSL_PROVIDER *prov); const OSSL_ITEM *OSSL_PROVIDER_get_param_types(OSSL_PROVIDER *prov); int OSSL_PROVIDER_get_params(OSSL_PROVIDER *prov, const OSSL_PARAM params[]); int OSSL_PROVIDER_add_builtin(OPENSSL_CTX *, const char *name, ossl_provider_init_fn *init_fn); =head1 DESCRIPTION B is a type that holds internal information about implementation providers (see L 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. =head2 Functions OSSL_PROVIDER_add_builtin() is used to add a built in provider to B 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, C. OSSL_PROVIDER_unload() unloads the given provider. For a provider added with OSSL_PROVIDER_add_builtin(), this simply runs its teardown function. OSSL_PROVIDER_get_param_types() is used to get a provider parameter descriptor set as an B array. Each element is a tuple of an B parameter type and a name in form of a C string. See L for more information on B and parameter types. OSSL_PROVIDER_get_params() is used to get provider parameter values. The caller must prepare the B array before calling this function, and the variables acting as buffers for this parameter array should be filled with data when it returns successfully. =head1 RETURN VALUES OSSL_PROVIDER_add() returns 1 on success, or 0 on error. OSSL_PROVIDER_load() returns a pointer to a provider object on success, or B on error. OSSL_PROVIDER_unload() returns 1 on success, or 0 on error. OSSL_PROVIDER_get_param_types() returns a pointer to a constant array of B, or NULL if none is provided. OSSL_PROVIDER_get_params() returns 1 on success, or 0 on error. =head1 EXAMPLES This demonstrates how to load the provider module "foo" and ask for its build number. OSSL_PROVIDER *prov = NULL; const char *build = NULL; size_t built_l = 0; const OSSL_PARAM request[] = { { "build", OSSL_PARAM_UTF8_STRING_PTR, &build, 0, &build_l }, { NULL, 0, NULL, 0, NULL } }; if ((prov = OSSL_PROVIDER_load(NULL, "foo")) != NULL && OSSL_PROVIDER_get_params(prov, request)) printf("Provider 'foo' build %s\n", build); else ERR_print_errors_fp(stderr); =head1 SEE ALSO L, L =head1 HISTORY The type and functions described here were added in OpenSSL 3.0. =head1 COPYRIGHT Copyright 2019 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 L. =cut