1=pod
2
3=head1 NAME
4
5OSSL_METHOD_STORE, ossl_method_store_new, ossl_method_store_free,
6ossl_method_store_init, ossl_method_store_cleanup,
7ossl_method_store_add, ossl_method_store_fetch,
8ossl_method_store_remove, ossl_method_store_remove_all_provided,
9ossl_method_store_cache_get, ossl_method_store_cache_set,
10ossl_method_store_cache_flush_all
11- implementation method store and query
12
13=head1 SYNOPSIS
14
15 #include "internal/property.h"
16
17 typedef struct ossl_method_store_st OSSL_METHOD_STORE;
18
19 OSSL_METHOD_STORE *ossl_method_store_new(OSSL_LIB_CTX *ctx);
20 void ossl_method_store_free(OSSL_METHOD_STORE *store);
21 int ossl_method_store_init(OSSL_LIB_CTX *ctx);
22 void ossl_method_store_cleanup(OSSL_LIB_CTX *ctx);
23 int ossl_method_store_add(OSSL_METHOD_STORE *store, const OSSL_PROVIDER *prov,
24                           int nid, const char *properties, void *method,
25                           int (*method_up_ref)(void *),
26                           void (*method_destruct)(void *));
27 int ossl_method_store_remove(OSSL_METHOD_STORE *store,
28                              int nid, const void *method);
29 int ossl_method_store_fetch(OSSL_METHOD_STORE *store,
30                             int nid, const char *properties,
31                             void **method, const OSSL_PROVIDER **prov_rw);
32 int ossl_method_store_remove_all_provided(OSSL_METHOD_STORE *store,
33                                           const OSSL_PROVIDER *prov);
34
35 int ossl_method_store_cache_get(OSSL_METHOD_STORE *store, OSSL_PROVIDER *prov,
36                                 int nid, const char *prop_query, void **method);
37 int ossl_method_store_cache_set(OSSL_METHOD_STORE *store, OSSL_PROVIDER *prov,
38                                 int nid, const char *prop_query, void *method,
39                                 int (*method_up_ref)(void *),
40                                 void (*method_destruct)(void *));
41 void ossl_method_store_cache_flush_all(OSSL_METHOD_STORE *store);
42
43=head1 DESCRIPTION
44
45OSSL_METHOD_STORE stores methods that can be queried using properties and a
46numeric identity (nid).
47
48Methods are expected to be library internal structures.
49It's left to the caller to define the exact contents.
50
51Numeric identities are expected to be an algorithm identity for the methods.
52It's left to the caller to define exactly what an algorithm is, and to allocate
53these numeric identities accordingly.
54
55The B<OSSL_METHOD_STORE> also holds an internal query cache, which is accessed
56separately (see L</Cache Functions> below).
57
58=head2 Store Functions
59
60ossl_method_store_init() initialises the method store subsystem in the scope of
61the library context I<ctx>.
62
63ossl_method_store_cleanup() cleans up and shuts down the implementation method
64store subsystem in the scope of the library context I<ctx>.
65
66ossl_method_store_new() create a new empty method store using the supplied
67I<ctx> to allow access to the required underlying property data.
68
69ossl_method_store_free() frees resources allocated to I<store>.
70
71ossl_method_store_add() adds the I<method> constructed from an implementation in
72the provider I<prov> to the I<store> as an instance of an algorithm indicated by
73I<nid> and the property definition I<properties>, unless the I<store> already
74has a method from the same provider with the same I<nid> and I<properties>.
75If the I<method_up_ref> function is given, it's called to increment the
76reference count of the method.
77If the I<method_destruct> function is given, it's called when this function
78fails to add the method to the store, or later on when it is being released from
79the I<store>.
80
81ossl_method_store_remove() removes the I<method> identified by I<nid> from the
82I<store>.
83
84ossl_method_store_fetch() queries I<store> for a method identified by I<nid>
85that matches the property query I<prop_query>.
86I<*prop> may be a pointer to a provider, which will narrow the search
87to methods from that provider.
88The result, if any, is returned in I<*method>, and its provider in I<*prov>.
89
90ossl_method_store_remove_all_provided() removes all methods from I<store>
91that are provided by I<prov>.
92When doing so, it also flushes the corresponding cache entries.
93
94=head2 Cache Functions
95
96ossl_method_store_cache_get() queries the cache associated with the I<store>
97for a method identified by I<nid> that matches the property query
98I<prop_query>.
99Additionally, if I<prov> isn't NULL, it will be used to narrow the search
100to only include methods from that provider.
101The result, if any, is returned in I<method>.
102
103ossl_method_store_cache_set() sets a cache entry identified by I<nid> from the
104provider I<prov>, with the property query I<prop_query> in the I<store>.
105Future calls to ossl_method_store_cache_get() will return the specified I<method>.
106The I<method_up_ref> function is called to increment the
107reference count of the method and the I<method_destruct> function is called
108to decrement it.
109
110ossl_method_store_cache_flush_all() flushes all cached entries associated with
111I<store>.
112
113=head1 NOTES
114
115The I<prop_query> argument to ossl_method_store_cache_get() and
116ossl_method_store_cache_set() is not allowed to be NULL.  Use "" for an
117empty property definition or query.
118
119=head1 RETURN VALUES
120
121ossl_method_store_new() returns a new method store object or NULL on failure.
122
123ossl_method_store_free(), ossl_method_store_add(),
124ossl_method_store_remove(), ossl_method_store_fetch(),
125ossl_method_store_cache_get(), ossl_method_store_cache_set() and
126ossl_method_store_flush_cache() return B<1> on success and B<0> on error.
127
128ossl_method_store_free() and ossl_method_store_cleanup() do not return any value.
129
130=head1 HISTORY
131
132This functionality was added to OpenSSL 3.0.
133
134=head1 COPYRIGHT
135
136Copyright 2019-2022 The OpenSSL Project Authors. All Rights Reserved.
137Copyright (c) 2019, Oracle and/or its affiliates.  All rights reserved.
138
139Licensed under the Apache License 2.0 (the "License").  You may not use this
140file except in compliance with the License.  You can obtain a copy in the file
141LICENSE in the source distribution or at
142L<https://www.openssl.org/source/license.html>.
143
144=cut
145