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, const char *name,
19 const char *propquery, void *data);
20 /* Store a method in a store */
21 int (*put)(OPENSSL_CTX *libctx, void *store, void *method,
22 const char *name, const char *propdef, void *data);
23 /* Construct a new method */
24 void *(*construct)(const char *name, const OSSL_DISPATCH *fns,
25 OSSL_PROVIDER *prov, void *data);
26 /* Destruct a method */
27 void (*destruct)(void *method);
29 typedef struct ossl_method_construct_method OSSL_METHOD_CONSTRUCT_METHOD;
31 void *ossl_method_construct(OPENSSL_CTX *ctx, int operation_id,
32 const char *name, const char *properties,
34 OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data);
39 All libcrypto sub-systems that want to create their own methods based
40 on provider dispatch tables need to do so in exactly the same way.
41 ossl_method_construct() does this while leaving it to the sub-systems
42 to define more precisely how the methods are created, stored, etc.
46 ossl_method_construct() creates a method by asking all available
47 providers for a dispatch table given an C<operation_id>, an algorithm
48 C<name> and a set of C<properties>, and then calling appropriate
49 functions given by the sub-system specific method creator through
50 C<mcm> and the data in C<mcm_data> (which is passed by
51 ossl_method_construct()).
53 This function assumes that the sub-system method creator implements
54 reference counting and acts accordingly (i.e. it will call the
55 sub-system destruct() method to decrement the reference count when
60 A central part of constructing a sub-system specific method is to give
61 ossl_method_construct a set of functions, all in the
62 C<OSSL_METHOD_CONSTRUCT_METHOD> structure, which holds the following
67 =item alloc_tmp_store()
69 Create a temporary method store in the scope of the library context C<ctx>.
70 This store is used to temporarily store methods for easier lookup, for
71 when the provider doesn't want its dispatch table stored in a longer
74 =item dealloc_tmp_store()
76 Remove a temporary store.
80 Look up an already existing method from a store by name.
82 The store may be given with C<store>.
83 B<NULL> is a valid value and means that a sub-system default store
85 This default store should be stored in the library context C<libctx>.
87 The method to be looked up should be identified with the given C<name> and
89 (which is the C<mcm_data> that was passed to ossl_construct_method())
90 and the provided property query C<propquery>.
92 This function is expected to increment the method's reference count.
96 Places the C<method> created by the construct() function (see below)
99 The store may be given with C<store>.
100 B<NULL> is a valid value and means that a sub-system default store
102 This default store should be stored in the library context C<libctx>.
104 The method should be associated with the given C<name> and property definition
105 C<propdef> as well as any identification data given through C<data> (which is
106 the C<mcm_data> that was passed to ossl_construct_method()).
108 This function is expected to increment the C<method>'s reference count.
112 Constructs a sub-system method for the given C<name> and the given
113 dispatch table C<fns>.
115 The associated I<provider object> C<prov> is passed as well, to make
116 it possible for the sub-system constructor to keep a reference, which
118 If such a reference is kept, the I<provider object> reference counter
119 must be incremented, using ossl_provider_upref().
121 This function is expected to set the method's reference count to 1.
125 Decrement the C<method>'s reference count, and destruct it when
126 the reference count reaches zero.
132 ossl_method_construct() returns a constructed method on success, or
137 This functionality was added to OpenSSL 3.0.
141 Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
143 Licensed under the Apache License 2.0 (the "License"). You may not use this
144 file except in compliance with the License. You can obtain a copy in the file
145 LICENSE in the source distribution or at
146 L<https://www.openssl.org/source/license.html>.