=pod =head1 NAME ossl_provider_find, ossl_provider_new, ossl_provider_upref, ossl_provider_free, ossl_provider_add_module_location, ossl_provider_set_fallback, ossl_provider_activate, ossl_provider_ctx, ossl_provider_forall_loaded, ossl_provider_name, ossl_provider_dso, ossl_provider_module_name, ossl_provider_module_path, ossl_provider_teardown, ossl_provider_get_param_types, ossl_provider_get_params, ossl_provider_query_operation - internal provider routines =head1 SYNOPSIS #include "internal/provider.h" OSSL_PROVIDER *ossl_provider_find(OPENSSL_CTX *libctx, const char *name); OSSL_PROVIDER *ossl_provider_new(OPENSSL_CTX *libctx, const char *name, ossl_provider_init_fn *init_function); int ossl_provider_upref(OSSL_PROVIDER *prov); void ossl_provider_free(OSSL_PROVIDER *prov); /* Setters */ int ossl_provider_add_module_location(OSSL_PROVIDER *prov, const char *loc); int ossl_provider_set_fallback(OSSL_PROVIDER *prov); /* Load and initialize the Provider */ int ossl_provider_activate(OSSL_PROVIDER *prov); /* Return pointer to the provider's context */ void *ossl_provider_ctx(const OSSL_PROVIDER *prov); /* Iterate over all loaded providers */ int ossl_provider_forall_loaded(OPENSSL_CTX *, int (*cb)(OSSL_PROVIDER *provider, void *cbdata), void *cbdata); /* Getters for other library functions */ const char *ossl_provider_name(OSSL_PROVIDER *prov); const DSO *ossl_provider_dso(OSSL_PROVIDER *prov); const char *ossl_provider_module_name(OSSL_PROVIDER *prov); const char *ossl_provider_module_path(OSSL_PROVIDER *prov); /* Thin wrappers around calls to the provider */ void ossl_provider_teardown(const OSSL_PROVIDER *prov); const OSSL_ITEM *ossl_provider_get_param_types(const OSSL_PROVIDER *prov); int ossl_provider_get_params(const OSSL_PROVIDER *prov, OSSL_PARAM params[]); const OSSL_ALGORITHM *ossl_provider_query_operation(const OSSL_PROVIDER *prov, int operation_id, int *no_cache); =head1 DESCRIPTION C is a type that holds all the necessary information to handle a provider, regardless of if it's built in to the application or the OpenSSL libraries, or if it's a loadable provider module. Instances of this type are commonly refered to as Is. A I is always stored in a set of Is in the library context. Is are reference counted. Is are initially inactive, i.e. they are only recorded in the store, but are not used. They are activated with the first call to ossl_provider_activate(), and are inactivated when ossl_provider_free() has been called as many times as ossl_provider_activate() has. =head2 Functions ossl_provider_find() finds an existing I in the I store by C. The I it finds gets its reference count incremented. ossl_provider_new() creates a new I and stores it in the I store, unless there already is one there with the same name. The reference counter of a newly created I will always be 2; one for being added to the store, and one for the returned reference. To indicate a built-in provider, the C argument must point at the provider initialization function for that provider. ossl_provider_free() decrements a I's reference counter; if it drops below 2, the I is assumed to have fallen out of use and will be inactivated (its teardown function is called); if it drops down to zero, the I is assumed to have been taken out of the store, and the associated module will be unloaded if one was loaded, and the I will be freed. ossl_provider_add_module_location() adds a location to look for a provider module. ossl_provider_set_fallback() marks an available provider as fallback. Note that after this call, the I pointer that was used can simply be dropped, but not freed. ossl_provider_activate() "activates" the provider for the given I. What "activates" means depends on what type of I it is: =over 4 =item * If an initialization function was given with ossl_provider_new(), that function will get called. =item * If no intialization function was given with ossl_provider_new(), a loadable module with the C that was given to ossl_provider_new() will be located and loaded, then the symbol C will be located in that module, and called. =back ossl_provider_ctx() returns a context created by the provider. Outside of the provider, it's completely opaque, but it needs to be passed back to some of the provider functions. ossl_provider_forall_loaded() iterates over all the currently "activated" providers, and calls C for each of them. If no providers have been "activated" yet, it tries to activate all available fallback providers and tries another iteration. ossl_provider_name() returns the name that was given with ossl_provider_new(). ossl_provider_dso() returns a reference to the module, for providers that come in the form of loadable modules. ossl_provider_module_name() returns the file name of the module, for providers that come in the form of loadable modules. ossl_provider_module_path() returns the full path of the module file, for providers that come in the form of loadable modules. ossl_provider_teardown() calls the provider's C function, if the provider has one. ossl_provider_get_param_types() calls the provider's C function, if the provider has one. It should return an array of C to describe all the parameters that the provider has for the I. ossl_provider_get_params() calls the provider's parameter request responder. It should treat the given C array as described in L. ossl_provider_query_operation() calls the provider's C function, if the provider has one. It should return an array of C for the given C. =head1 NOTES Locating a provider module happens as follows: =over 4 =item 1. Look in each directory given by ossl_provider_add_module_location(). =item 2. Look in the directory given by the environment variable B. =item 3. Look in the directory given by the OpenSSL built in macro B. =back =head1 RETURN VALUES ossl_provider_find() and ossl_provider_new() return a pointer to a I (C) on success, or B on error. ossl_provider_upref() returns the value of the reference counter after it has been incremented. ossl_provider_free() doesn't return any value. ossl_provider_add_module_location(), ossl_provider_set_fallback() and ossl_provider_activate() return 1 on success, or 0 on error. ossl_provider_name(), ossl_provider_dso(), ossl_provider_module_name(), and ossl_provider_module_path() return a pointer to their respective data if it's available, otherwise B is returned. ossl_provider_teardown() doesnt't return any value. ossl_provider_get_param_types() returns a pointer to an C array if this function is available in the provider, otherwise B. ossl_provider_get_params() returns 1 on success, or 0 on error. If this function isn't available in the provider, 0 is returned. =head1 SEE ALSO L, L =head1 HISTORY The functions described here were all 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