Add internal function ossl_algorithm_do_all()

This function is used to traverse all the implementations provided by
one provider, or all implementation for a specific operation across
all loaded providers, or both, and execute a given function for each
occurence.

This will be used by ossl_method_construct(), but also by information
processing functions.

Reviewed-by: Paul Dale <paul.dale@oracle.com>
(Merged from https://github.com/openssl/openssl/pull/9356)

crypto/build.info

@@ -59,7 +59,8 @@ IF[{- !$disabled{asm} && $config{processor} ne '386' -}]
 ENDIF
 
 # The Core
-$CORE_COMMON=provider_core.c provider_predefined.c core_fetch.c core_namemap.c
+$CORE_COMMON=provider_core.c provider_predefined.c \
+        core_fetch.c core_algorithm.c core_namemap.c
 
 SOURCE[../libcrypto]=$CORE_COMMON provider_conf.c
 SOURCE[../providers/fips]=$CORE_COMMON

crypto/core_algorithm.c

@@ -0,0 +1,75 @@
+/*
+ * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+ *
+ * Licensed under the Apache License 2.0 (the "License").  You may not use
+ * this file except in compliance with the License.  You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
+ */
+
+#include <openssl/core.h>
+#include <openssl/core_numbers.h>
+#include "internal/core.h"
+#include "internal/property.h"
+#include "internal/provider.h"
+
+struct algorithm_data_st {
+    OPENSSL_CTX *libctx;
+    int operation_id;            /* May be zero for finding them all */
+    void (*fn)(OSSL_PROVIDER *, const OSSL_ALGORITHM *, int no_store,
+               void *data);
+    void *data;
+};
+
+static int algorithm_do_this(OSSL_PROVIDER *provider, void *cbdata)
+{
+    struct algorithm_data_st *data = cbdata;
+    int no_store = 0;    /* Assume caching is ok */
+    int first_operation = 1;
+    int last_operation = OSSL_OP__HIGHEST;
+    int cur_operation;
+    int ok = 0;
+
+    if (data->operation_id != 0)
+        first_operation = last_operation = data->operation_id;
+
+    for (cur_operation = first_operation;
+         cur_operation <= last_operation;
+         cur_operation++) {
+        const OSSL_ALGORITHM *map =
+            ossl_provider_query_operation(provider, data->operation_id,
+                                          &no_store);
+
+        if (map == NULL)
+            break;
+
+        ok = 1;                  /* As long as we've found *something* */
+        while (map->algorithm_name != NULL) {
+            const OSSL_ALGORITHM *thismap = map++;
+
+            data->fn(provider, thismap, no_store, data->data);
+        }
+    }
+
+    return ok;
+}
+
+void ossl_algorithm_do_all(OPENSSL_CTX *libctx, int operation_id,
+                           OSSL_PROVIDER *provider,
+                           void (*fn)(OSSL_PROVIDER *provider,
+                                      const OSSL_ALGORITHM *algo,
+                                      int no_store, void *data),
+                           void *data)
+{
+    struct algorithm_data_st cbdata;
+
+    cbdata.libctx = libctx;
+    cbdata.operation_id = operation_id;
+    cbdata.fn = fn;
+    cbdata.data = data;
+
+    if (provider == NULL)
+        ossl_provider_forall_loaded(libctx, algorithm_do_this, &cbdata);
+    else
+        algorithm_do_this(provider, &cbdata);
+}

doc/internal/man3/ossl_algorithm_do_all.pod

@@ -0,0 +1,63 @@
+=pod
+
+=head1 NAME
+
+ossl_algorithm_do_all - generic algorithm implementation iterator
+
+=head1 SYNOPSIS
+
+ void ossl_algorithm_do_all(OPENSSL_CTX *libctx, int operation_id,
+                            OSSL_PROVIDER *provider,
+                            void (*fn)(OSSL_PROVIDER *provider,
+                                       const OSSL_ALGORITHM *algo,
+                                       int no_store, void *data),
+                            void *data)
+
+=head1 DESCRIPTION
+
+ossl_algorithm_do_all() looks up every algorithm it can find, given a
+library context I<libctx>, an operation identity I<operation_id> and a
+provider I<provider>.
+I<libctx> may be NULL to signify that the default library context should
+be used.
+I<operation_id> may be zero to signify that all kinds of operations
+will be looked up.
+I<provider> may be NULL to signify that all loaded providers will be
+queried.
+
+For each implementation found, the function I<fn> is called with the
+I<provider> for the implementation, the algorithm descriptor I<algo>,
+the flag I<no_store> indicating whether the algorithm descriptor may
+be remembered or not, and the caller I<data> that was passed to
+ossl_algorithm_do_all().
+
+=head1 RETURN VALUES
+
+ossl_algorithm_do_all() doesn't return any value.
+
+=head1 NOTES
+
+The function described here are mainly useful for discovery, and
+possibly display of what has been discovered, for example an
+application that wants to display the loaded providers and what they
+may offer, but also for constructors, such as
+L<ossl_construct_method(3)>.
+
+=head1 SEE ALSO
+
+L<ossl_construct_method(3)>, L<EVP_MAC_do_all(3)>
+
+=head1 HISTORY
+
+This functionality was added to OpenSSL 3.0.
+
+=head1 COPYRIGHT
+
+Copyright 2019 The OpenSSL Project Authors. All Rights Reserved.
+
+Licensed under the Apache License 2.0 (the "License").  You may not use this
+file except in compliance with the License.  You can obtain a copy in the file
+LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
+
+=cut

include/internal/core.h

@@ -51,4 +51,11 @@ void *ossl_method_construct(OPENSSL_CTX *ctx, int operation_id,
                             int force_cache,
                             OSSL_METHOD_CONSTRUCT_METHOD *mcm, void *mcm_data);
 
+void ossl_algorithm_do_all(OPENSSL_CTX *libctx, int operation_id,
+                           OSSL_PROVIDER *provider,
+                           void (*fn)(OSSL_PROVIDER *provider,
+                                      const OSSL_ALGORITHM *algo,
+                                      int no_store, void *data),
+                           void *data);
+
 #endif

include/openssl/core_numbers.h

@@ -324,6 +324,9 @@ OSSL_CORE_MAKE_FUNC(void *, OP_keyexch_dupctx, (void *ctx))
 OSSL_CORE_MAKE_FUNC(int, OP_keyexch_set_params, (void *ctx,
                                                  OSSL_PARAM params[]))
 
+/* Highest known operation number */
+# define OSSL_OP__HIGHEST                            3
+
 # ifdef __cplusplus
 }
 # endif