Implement OSSL_PROVIDER_get0_default_search_path, add docs and tests.

Reviewed-by: Todd Short <todd.short@me.com>
Reviewed-by: Tomas Mraz <tomas@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/19752)

3 files changed, 82 insertions, 0 deletions

diff --git a/test/build.info b/test/build.info
index fb6a4551db..0722eff32d 100644
--- a/test/build.info
+++ b/test/build.info
@@ -979,6 +979,11 @@ IF[{- !$disabled{tests} -}]
   INCLUDE[provider_pkey_test]=../include ../apps/include
   DEPEND[provider_pkey_test]=../libcrypto libtestutil.a
 
+  PROGRAMS{noinst}=provider_default_search_path_test
+  SOURCE[provider_default_search_path_test]=provider_default_search_path_test.c
+  INCLUDE[provider_default_search_path_test]=../include ../apps/include
+  DEPEND[provider_default_search_path_test]=../libcrypto libtestutil.a
+
   PROGRAMS{noinst}=params_test
   SOURCE[params_test]=params_test.c
   INCLUDE[params_test]=.. ../include ../apps/include
diff --git a/test/provider_default_search_path_test.c b/test/provider_default_search_path_test.c
new file mode 100644
index 0000000000..684a508765
--- /dev/null
+++ b/test/provider_default_search_path_test.c
@@ -0,0 +1,59 @@
+/*
+ * Copyright 2020-2022 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 <stddef.h>
+#include <openssl/provider.h>
+#include "testutil.h"
+
+static int test_default_libctx(void)
+{
+    OSSL_LIB_CTX *ctx = NULL;
+    char *path = "./some/path";
+    const char *retrieved_path = NULL;
+    int ok;
+
+    ok = TEST_true(OSSL_PROVIDER_set_default_search_path(ctx, path))
+        && TEST_ptr(retrieved_path = OSSL_PROVIDER_get0_default_search_path(ctx))
+        && TEST_str_eq(path, retrieved_path);
+
+    return ok;
+}
+
+static int test_explicit_libctx(void)
+{
+    OSSL_LIB_CTX *ctx = NULL;
+    char *def_libctx_path = "./some/path";
+    char *path = "./another/location";
+    const char *retrieved_defctx_path = NULL;
+    const char *retrieved_path = NULL;
+    int ok;
+
+         /* Set search path for default context, then create a new context and set
+            another path for it. Finally, get both paths and make sure they are
+            still what we set and are separate. */
+    ok = TEST_true(OSSL_PROVIDER_set_default_search_path(NULL, def_libctx_path))
+        && TEST_ptr(ctx = OSSL_LIB_CTX_new())
+        && TEST_true(OSSL_PROVIDER_set_default_search_path(ctx, path))
+        && TEST_ptr(retrieved_defctx_path = OSSL_PROVIDER_get0_default_search_path(NULL))
+        && TEST_str_eq(def_libctx_path, retrieved_defctx_path)
+        && TEST_ptr(retrieved_path = OSSL_PROVIDER_get0_default_search_path(ctx))
+        && TEST_str_eq(path, retrieved_path)
+        && TEST_str_ne(retrieved_path, retrieved_defctx_path);
+
+    OSSL_LIB_CTX_free(ctx);
+    return ok;
+}
+
+int setup_tests(void)
+{
+    ADD_TEST(test_default_libctx);
+    ADD_TEST(test_explicit_libctx);
+    return 1;
+}
+
diff --git a/test/recipes/04-test_provider_default_search_path.t b/test/recipes/04-test_provider_default_search_path.t
new file mode 100644
index 0000000000..29797e62a0
--- /dev/null
+++ b/test/recipes/04-test_provider_default_search_path.t
@@ -0,0 +1,18 @@
+#! /usr/bin/env perl
+# Copyright 2019-2022 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
+
+use strict;
+use File::Spec;
+use OpenSSL::Test::Simple;
+
+# We must ensure that OPENSSL_CONF points at an empty file.  Otherwise, we
+# risk that the configuration file contains statements that load providers,
+# which defeats the purpose of this test.  The NUL device is good enough.
+$ENV{OPENSSL_CONF} = File::Spec->devnull();
+
+simple_test("test_provider_default_search_path", "provider_default_search_path_test");