doc/man3/OSSL_PROVIDER.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 OSSL_PROVIDER, OSSL_PROVIDER_load, OSSL_PROVIDER_unload,
   6 OSSL_PROVIDER_get_param_types, OSSL_PROVIDER_get_params,
   7 OSSL_PROVIDER_add_builtin, OSSL_PROVIDER_name - provider routines
   8
   9 =head1 SYNOPSIS
  10
  11  #include <openssl/provider.h>
  12
  13  typedef struct ossl_provider_st OSSL_PROVIDER;
  14
  15  OSSL_PROVIDER *OSSL_PROVIDER_load(OPENSSL_CTX *, const char *name);
  16  int OSSL_PROVIDER_unload(OSSL_PROVIDER *prov);
  17
  18  const OSSL_ITEM *OSSL_PROVIDER_get_param_types(OSSL_PROVIDER *prov);
  19  int OSSL_PROVIDER_get_params(OSSL_PROVIDER *prov, OSSL_PARAM params[]);
  20
  21  int OSSL_PROVIDER_add_builtin(OPENSSL_CTX *, const char *name,
  22                                ossl_provider_init_fn *init_fn);
  23
  24  const char *OSSL_PROVIDER_name(const OSSL_PROVIDER *prov);
  25
  26 =head1 DESCRIPTION
  27
  28 B<OSSL_PROVIDER> is a type that holds internal information about
  29 implementation providers (see L<provider(7)> for information on what a
  30 provider is).
  31 A provider can be built in to the application or the OpenSSL
  32 libraries, or can be a loadable module.
  33 The functions described here handle both forms.
  34
  35 =head2 Functions
  36
  37 OSSL_PROVIDER_add_builtin() is used to add a built in provider to
  38 B<OSSL_PROVIDER> store in the given library context, by associating a
  39 provider name with a provider initialization function.
  40 This name can then be used with OSSL_PROVIDER_load().
  41
  42 OSSL_PROVIDER_load() loads and initializes a provider.
  43 This may simply initialize a provider that was previously added with
  44 OSSL_PROVIDER_add_builtin() and run its given initialization function,
  45 or load a provider module with the given name and run its provider
  46 entry point, C<OSSL_provider_init>.
  47
  48 OSSL_PROVIDER_unload() unloads the given provider.
  49 For a provider added with OSSL_PROVIDER_add_builtin(), this simply
  50 runs its teardown function.
  51
  52 OSSL_PROVIDER_get_param_types() is used to get a provider parameter
  53 descriptor set as an B<OSSL_ITEM> array.
  54 Each element is a tuple of an B<OSSL_PARAM> parameter type and a name
  55 in form of a C string.
  56 See L<openssl-core.h(7)> for more information on B<OSSL_ITEM> and
  57 parameter types.
  58
  59 OSSL_PROVIDER_get_params() is used to get provider parameter values.
  60 The caller must prepare the B<OSSL_PARAM> array before calling this
  61 function, and the variables acting as buffers for this parameter array
  62 should be filled with data when it returns successfully.
  63
  64 OSSL_PROVIDER_name() returns the name of the given provider.
  65
  66 =head1 RETURN VALUES
  67
  68 OSSL_PROVIDER_add() returns 1 on success, or 0 on error.
  69
  70 OSSL_PROVIDER_load() returns a pointer to a provider object on
  71 success, or B<NULL> on error.
  72
  73 OSSL_PROVIDER_unload() returns 1 on success, or 0 on error.
  74
  75 OSSL_PROVIDER_get_param_types() returns a pointer to a constant array
  76 of B<OSSL_ITEM>, or NULL if none is provided.
  77
  78 OSSL_PROVIDER_get_params() returns 1 on success, or 0 on error.
  79
  80 =head1 EXAMPLES
  81
  82 This demonstrates how to load the provider module "foo" and ask for
  83 its build number.
  84
  85  OSSL_PROVIDER *prov = NULL;
  86  const char *build = NULL;
  87  size_t built_l = 0;
  88  OSSL_PARAM request[] = {
  89      { "build", OSSL_PARAM_UTF8_STRING_PTR, &build, 0, &build_l },
  90      { NULL, 0, NULL, 0, NULL }
  91  };
  92
  93  if ((prov = OSSL_PROVIDER_load(NULL, "foo")) != NULL
  94      && OSSL_PROVIDER_get_params(prov, request))
  95      printf("Provider 'foo' build %s\n", build);
  96  else
  97      ERR_print_errors_fp(stderr);
  98
  99 =head1 SEE ALSO
 100
 101 L<openssl-core.h(7)>, L<provider(7)>
 102
 103 =head1 HISTORY
 104
 105 The type and functions described here were added in OpenSSL 3.0.
 106
 107 =head1 COPYRIGHT
 108
 109 Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
 110
 111 Licensed under the Apache License 2.0 (the "License").  You may not use
 112 this file except in compliance with the License.  You can obtain a copy
 113 in the file LICENSE in the source distribution or at
 114 L<https://www.openssl.org/source/license.html>.
 115
 116 =cut