Implement the ability to convert a PROPERTY_LIST to a string

We have the ability to parse a string into a PROPERTY_LIST already. Now
we have the ability to go the other way.

Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/15242)

1 files changed, 44 insertions, 0 deletions

diff --git a/crypto/property/property_string.c b/crypto/property/property_string.c
index 9eb55cb461..06f58496db 100644
--- a/crypto/property/property_string.c
+++ b/crypto/property/property_string.c
@@ -162,6 +162,45 @@ OSSL_PROPERTY_IDX ossl_property_name(OSSL_LIB_CTX *ctx, const char *s,
                                 s);
 }
 
+struct find_str_st {
+    const char *str;
+    OSSL_PROPERTY_IDX idx;
+};
+
+static void find_str_fn(PROPERTY_STRING *prop, void *vfindstr)
+{
+    struct find_str_st *findstr = vfindstr;
+
+    if (prop->idx == findstr->idx)
+        findstr->str = prop->s;
+}
+
+static const char *ossl_property_str(int name, OSSL_LIB_CTX *ctx,
+                                     OSSL_PROPERTY_IDX idx)
+{
+    struct find_str_st findstr;
+    PROPERTY_STRING_DATA *propdata
+        = ossl_lib_ctx_get_data(ctx, OSSL_LIB_CTX_PROPERTY_STRING_INDEX,
+                                &property_string_data_method);
+
+    if (propdata == NULL)
+        return NULL;
+
+    findstr.str = NULL;
+    findstr.idx = idx;
+
+    lh_PROPERTY_STRING_doall_arg(name ? propdata->prop_names
+                                      : propdata->prop_values,
+                                 find_str_fn, &findstr);
+
+    return findstr.str;
+}
+
+const char *ossl_property_name_str(OSSL_LIB_CTX *ctx, OSSL_PROPERTY_IDX idx)
+{
+    return ossl_property_str(1, ctx, idx);
+}
+
 OSSL_PROPERTY_IDX ossl_property_value(OSSL_LIB_CTX *ctx, const char *s,
                                       int create)
 {
@@ -175,3 +214,8 @@ OSSL_PROPERTY_IDX ossl_property_value(OSSL_LIB_CTX *ctx, const char *s,
                                 create ? &propdata->prop_value_idx : NULL,
                                 s);
 }
+
+const char *ossl_property_value_str(OSSL_LIB_CTX *ctx, OSSL_PROPERTY_IDX idx)
+{
+    return ossl_property_str(0, ctx, idx);
+}