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, void *data);
19 /* Store a method in a store */
20 int (*put)(OPENSSL_CTX *libctx, void *store, void *method,
21 const OSSL_PROVIDER *prov, int operation_id, const char *name,
22 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,
33 OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data);
38 All libcrypto sub-systems that want to create their own methods based
39 on provider dispatch tables need to do so in exactly the same way.
40 ossl_method_construct() does this while leaving it to the sub-systems
41 to define more precisely how the methods are created, stored, etc.
43 It's important to keep in mind that a method is identified by three things:
47 =item The operation identity
49 =item The name of the algorithm
51 =item The properties associated with the algorithm implementation
57 ossl_method_construct() creates a method by asking all available
58 providers for a dispatch table given an I<operation_id>, and then
59 calling the appropriate functions given by the sub-system specific
60 method creator through I<mcm> and the data in I<mcm_data> (which is
61 passed by ossl_method_construct()).
63 This function assumes that the sub-system method creator implements
64 reference counting and acts accordingly (i.e. it will call the
65 sub-system destruct() method to decrement the reference count when
70 A central part of constructing a sub-system specific method is to give
71 ossl_method_construct a set of functions, all in the
72 B<OSSL_METHOD_CONSTRUCT_METHOD> structure, which holds the following
77 =item alloc_tmp_store()
79 Create a temporary method store in the scope of the library context I<ctx>.
80 This store is used to temporarily store methods for easier lookup, for
81 when the provider doesn't want its dispatch table stored in a longer
84 =item dealloc_tmp_store()
86 Remove a temporary store.
90 Look up an already existing method from a store by name.
92 The store may be given with I<store>.
93 NULL is a valid value and means that a sub-system default store
95 This default store should be stored in the library context I<libctx>.
97 The method to be looked up should be identified with data found in I<data>
98 (which is the I<mcm_data> that was passed to ossl_construct_method()).
99 In other words, the ossl_method_construct() caller is entirely responsible
100 for ensuring the necesssary data is made available.
102 This function is expected to increment the method's reference count.
106 Places the I<method> created by the construct() function (see below)
109 The store may be given with I<store>.
110 NULL is a valid value and means that a sub-system default store
112 This default store should be stored in the library context I<libctx>.
114 The method should be associated with the given I<operation_id>,
115 I<name> and property definition I<propdef> as well as any
116 identification data given through I<data> (which is the I<mcm_data>
117 that was passed to ossl_construct_method()).
119 This function is expected to increment the I<method>'s reference count.
123 Constructs a sub-system method for the given I<name> and the given
124 dispatch table I<fns>.
126 The associated provider object I<prov> is passed as well, to make
127 it possible for the sub-system constructor to keep a reference, which
129 If such a reference is kept, the I<provider object> reference counter
130 must be incremented, using ossl_provider_up_ref().
132 This function is expected to set the method's reference count to 1.
136 Decrement the I<method>'s reference count, and destruct it when
137 the reference count reaches zero.
143 ossl_method_construct() returns a constructed method on success, or
148 This functionality was added to OpenSSL 3.0.
152 Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
154 Licensed under the Apache License 2.0 (the "License"). You may not use this
155 file except in compliance with the License. You can obtain a copy in the file
156 LICENSE in the source distribution or at
157 L<https://www.openssl.org/source/license.html>.