5 OSSL_METHOD_CONSTRUCT_METHOD, ossl_method_construct
6 - generic method constructor
10 #include "internal/core.h"
12 struct ossl_method_construct_method_st {
14 void *(*alloc_tmp_store)(OPENSSL_CTX *ctx);
16 void (*dealloc_tmp_store)(void *store);
17 /* Get an already existing method from a store */
18 void *(*get)(OPENSSL_CTX *libctx, void *store,
19 int operation_id, const char *name, const char *propquery,
21 /* Store a method in a store */
22 int (*put)(OPENSSL_CTX *libctx, void *store, void *method,
23 int operation_id, const char *name, const char *propdef,
25 /* Construct a new method */
26 void *(*construct)(const char *name, const OSSL_DISPATCH *fns,
27 OSSL_PROVIDER *prov, void *data);
28 /* Destruct a method */
29 void (*destruct)(void *method);
31 typedef struct ossl_method_construct_method OSSL_METHOD_CONSTRUCT_METHOD;
33 void *ossl_method_construct(OPENSSL_CTX *ctx, int operation_id,
34 const char *name, const char *properties,
36 OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data);
41 All libcrypto sub-systems that want to create their own methods based
42 on provider dispatch tables need to do so in exactly the same way.
43 ossl_method_construct() does this while leaving it to the sub-systems
44 to define more precisely how the methods are created, stored, etc.
46 It's important to keep in mind that a method is identified by three things:
50 =item The operation identity
52 =item The name of the algorithm
54 =item The properties associated with the algorithm implementation
60 ossl_method_construct() creates a method by asking all available
61 providers for a dispatch table given an C<operation_id>, an algorithm
62 C<name> and a set of C<properties>, and then calling the appropriate
63 functions given by the sub-system specific method creator through
64 C<mcm> and the data in C<mcm_data> (which is passed by
65 ossl_method_construct()).
67 This function assumes that the sub-system method creator implements
68 reference counting and acts accordingly (i.e. it will call the
69 sub-system destruct() method to decrement the reference count when
74 A central part of constructing a sub-system specific method is to give
75 ossl_method_construct a set of functions, all in the
76 C<OSSL_METHOD_CONSTRUCT_METHOD> structure, which holds the following
81 =item alloc_tmp_store()
83 Create a temporary method store in the scope of the library context C<ctx>.
84 This store is used to temporarily store methods for easier lookup, for
85 when the provider doesn't want its dispatch table stored in a longer
88 =item dealloc_tmp_store()
90 Remove a temporary store.
94 Look up an already existing method from a store by name.
96 The store may be given with C<store>.
97 B<NULL> is a valid value and means that a sub-system default store
99 This default store should be stored in the library context C<libctx>.
101 The method to be looked up should be identified with the given
102 C<operation_id>, C<name>, the provided property query C<propquery>
103 and data from C<data> (which is the C<mcm_data> that was passed to
104 ossl_construct_method()).
106 This function is expected to increment the method's reference count.
110 Places the C<method> created by the construct() function (see below)
113 The store may be given with C<store>.
114 B<NULL> is a valid value and means that a sub-system default store
116 This default store should be stored in the library context C<libctx>.
118 The method should be associated with the given C<operation_id>,
119 C<name> and property definition C<propdef> as well as any
120 identification data given through C<data> (which is the C<mcm_data>
121 that was passed to ossl_construct_method()).
123 This function is expected to increment the C<method>'s reference count.
127 Constructs a sub-system method for the given C<name> and the given
128 dispatch table C<fns>.
130 The associated I<provider object> C<prov> is passed as well, to make
131 it possible for the sub-system constructor to keep a reference, which
133 If such a reference is kept, the I<provider object> reference counter
134 must be incremented, using ossl_provider_upref().
136 This function is expected to set the method's reference count to 1.
140 Decrement the C<method>'s reference count, and destruct it when
141 the reference count reaches zero.
147 ossl_method_construct() returns a constructed method on success, or
152 This functionality was added to OpenSSL 3.0.
156 Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
158 Licensed under the Apache License 2.0 (the "License"). You may not use this
159 file except in compliance with the License. You can obtain a copy in the file
160 LICENSE in the source distribution or at
161 L<https://www.openssl.org/source/license.html>.