| =pod |
| |
| =head1 NAME |
| |
| OSSL_DECODER, |
| OSSL_DECODER_fetch, |
| OSSL_DECODER_up_ref, |
| OSSL_DECODER_free, |
| OSSL_DECODER_get0_provider, |
| OSSL_DECODER_get0_properties, |
| OSSL_DECODER_is_a, |
| OSSL_DECODER_get0_name, |
| OSSL_DECODER_get0_description, |
| OSSL_DECODER_do_all_provided, |
| OSSL_DECODER_names_do_all, |
| OSSL_DECODER_gettable_params, |
| OSSL_DECODER_get_params |
| - Decoder method routines |
| |
| =head1 SYNOPSIS |
| |
| #include <openssl/decoder.h> |
| |
| typedef struct ossl_decoder_st OSSL_DECODER; |
| |
| OSSL_DECODER *OSSL_DECODER_fetch(OSSL_LIB_CTX *ctx, const char *name, |
| const char *properties); |
| int OSSL_DECODER_up_ref(OSSL_DECODER *decoder); |
| void OSSL_DECODER_free(OSSL_DECODER *decoder); |
| const OSSL_PROVIDER *OSSL_DECODER_get0_provider(const OSSL_DECODER *decoder); |
| const char *OSSL_DECODER_get0_properties(const OSSL_DECODER *decoder); |
| int OSSL_DECODER_is_a(const OSSL_DECODER *decoder, const char *name); |
| const char *OSSL_DECODER_get0_name(const OSSL_DECODER *decoder); |
| const char *OSSL_DECODER_get0_description(const OSSL_DECODER *decoder); |
| void OSSL_DECODER_do_all_provided(OSSL_LIB_CTX *libctx, |
| void (*fn)(OSSL_DECODER *decoder, void *arg), |
| void *arg); |
| int OSSL_DECODER_names_do_all(const OSSL_DECODER *decoder, |
| void (*fn)(const char *name, void *data), |
| void *data); |
| const OSSL_PARAM *OSSL_DECODER_gettable_params(OSSL_DECODER *decoder); |
| int OSSL_DECODER_get_params(OSSL_DECODER_CTX *ctx, const OSSL_PARAM params[]); |
| |
| =head1 DESCRIPTION |
| |
| B<OSSL_DECODER> is a method for decoders, which know how to |
| decode encoded data into an object of some type that the rest |
| of OpenSSL knows how to handle. |
| |
| OSSL_DECODER_fetch() looks for an algorithm within the provider that |
| has been loaded into the B<OSSL_LIB_CTX> given by I<ctx>, having the |
| name given by I<name> and the properties given by I<properties>. |
| The I<name> determines what type of object the fetched decoder |
| method is expected to be able to decode, and the properties are |
| used to determine the expected output type. |
| For known properties and the values they may have, please have a look |
| in L<provider-encoder(7)/Names and properties>. |
| |
| OSSL_DECODER_up_ref() increments the reference count for the given |
| I<decoder>. |
| |
| OSSL_DECODER_free() decrements the reference count for the given |
| I<decoder>, and when the count reaches zero, frees it. |
| |
| OSSL_DECODER_get0_provider() returns the provider of the given |
| I<decoder>. |
| |
| OSSL_DECODER_get0_properties() returns the property definition associated |
| with the given I<decoder>. |
| |
| OSSL_DECODER_is_a() checks if I<decoder> is an implementation |
| of an algorithm that's identifiable with I<name>. |
| |
| OSSL_DECODER_get0_name() returns the name used to fetch the given I<decoder>. |
| |
| OSSL_DECODER_get0_description() returns a description of the I<decoder>, meant |
| for display and human consumption. The description is at the discretion |
| of the I<decoder> implementation. |
| |
| OSSL_DECODER_names_do_all() traverses all names for the given |
| I<decoder>, and calls I<fn> with each name and I<data> as arguments. |
| |
| OSSL_DECODER_do_all_provided() traverses all decoder |
| implementations by all activated providers in the library context |
| I<libctx>, and for each of the implementations, calls I<fn> with the |
| implementation method and I<arg> as arguments. |
| |
| OSSL_DECODER_gettable_params() returns an L<OSSL_PARAM(3)> |
| array of parameter descriptors. |
| |
| OSSL_DECODER_get_params() attempts to get parameters specified |
| with an L<OSSL_PARAM(3)> array I<params>. Parameters that the |
| implementation doesn't recognise should be ignored. |
| |
| =head1 RETURN VALUES |
| |
| OSSL_DECODER_fetch() returns a pointer to an OSSL_DECODER object, |
| or NULL on error. |
| |
| OSSL_DECODER_up_ref() returns 1 on success, or 0 on error. |
| |
| OSSL_DECODER_free() doesn't return any value. |
| |
| OSSL_DECODER_get0_provider() returns a pointer to a provider object, or |
| NULL on error. |
| |
| OSSL_DECODER_get0_properties() returns a pointer to a property |
| definition string, or NULL on error. |
| |
| OSSL_DECODER_is_a() returns 1 if I<decoder> was identifiable, |
| otherwise 0. |
| |
| OSSL_DECODER_get0_name() returns the algorithm name from the provided |
| implementation for the given I<decoder>. Note that the I<decoder> may have |
| multiple synonyms associated with it. In this case the first name from the |
| algorithm definition is returned. Ownership of the returned string is retained |
| by the I<decoder> object and should not be freed by the caller. |
| |
| OSSL_DECODER_get0_description() returns a pointer to a description, or NULL if |
| there isn't one. |
| |
| OSSL_DECODER_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. |
| |
| =head1 NOTES |
| |
| OSSL_DECODER_fetch() may be called implicitly by other fetching |
| functions, using the same library context and properties. |
| Any other API that uses keys will typically do this. |
| |
| =head1 EXAMPLES |
| |
| To list all decoders in a provider to a bio_out: |
| |
| static void collect_decoders(OSSL_DECODER *decoder, void *stack) |
| { |
| STACK_OF(OSSL_DECODER) *decoder_stack = stack; |
| |
| sk_OSSL_DECODER_push(decoder_stack, decoder); |
| OSSL_DECODER_up_ref(decoder); |
| } |
| |
| void print_name(const char *name, void *vdata) |
| { |
| BIO *bio = vdata; |
| |
| BIO_printf(bio, "%s ", name); |
| } |
| |
| |
| STACK_OF(OSSL_DECODER) *decoders; |
| int i; |
| |
| decoders = sk_OSSL_DECODER_new_null(); |
| |
| BIO_printf(bio_out, "DECODERs provided by %s:\n", provider); |
| OSSL_DECODER_do_all_provided(NULL, collect_decoders, |
| decoders); |
| |
| for (i = 0; i < sk_OSSL_DECODER_num(decoders); i++) { |
| OSSL_DECODER *decoder = sk_OSSL_DECODER_value(decoders, i); |
| |
| if (strcmp(OSSL_PROVIDER_get0_name(OSSL_DECODER_get0_provider(decoder)), |
| provider) != 0) |
| continue; |
| |
| if (OSSL_DECODER_names_do_all(decoder, print_name, bio_out)) |
| BIO_printf(bio_out, "\n"); |
| } |
| sk_OSSL_DECODER_pop_free(decoders, OSSL_DECODER_free); |
| |
| =head1 SEE ALSO |
| |
| L<provider(7)>, L<OSSL_DECODER_CTX(3)>, L<OSSL_DECODER_from_bio(3)>, |
| L<OSSL_DECODER_CTX_new_for_pkey(3)>, L<OSSL_LIB_CTX(3)> |
| |
| =head1 HISTORY |
| |
| The functions described here were added in OpenSSL 3.0. |
| |
| =head1 COPYRIGHT |
| |
| Copyright 2020-2022 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<https://www.openssl.org/source/license.html>. |
| |
| =cut |