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)

3 files changed, 176 insertions, 0 deletions

diff --git a/crypto/property/property_local.h b/crypto/property/property_local.h
index c744a5d3c3..8cc3a51270 100644
--- a/crypto/property/property_local.h
+++ b/crypto/property/property_local.h
@@ -16,8 +16,10 @@ typedef int OSSL_PROPERTY_IDX;
 /* Property string functions */
 OSSL_PROPERTY_IDX ossl_property_name(OSSL_LIB_CTX *ctx, const char *s,
                                      int create);
+const char *ossl_property_name_str(OSSL_LIB_CTX *ctx, OSSL_PROPERTY_IDX idx);
 OSSL_PROPERTY_IDX ossl_property_value(OSSL_LIB_CTX *ctx, const char *s,
                                       int create);
+const char *ossl_property_value_str(OSSL_LIB_CTX *ctx, OSSL_PROPERTY_IDX idx);
 
 /* Property list functions */
 void ossl_property_free(OSSL_PROPERTY_LIST *p);
diff --git a/crypto/property/property_parse.c b/crypto/property/property_parse.c
index dfae76518f..aab8cbe8a4 100644
--- a/crypto/property/property_parse.c
+++ b/crypto/property/property_parse.c
@@ -616,3 +616,133 @@ int ossl_property_parse_init(OSSL_LIB_CTX *ctx)
 err:
     return 0;
 }
+
+static void put_char(char ch, char **buf, size_t *remain, size_t *needed)
+{
+    if (*remain == 0) {
+        ++*needed;
+        return;
+    }
+    if(*remain == 1)
+        **buf = '\0';
+    else
+        **buf = ch;
+    ++*buf;
+    ++*needed;
+    --*remain;
+}
+
+static void put_str(const char *str, char **buf, size_t *remain, size_t *needed)
+{
+    size_t olen, len;
+
+    len = olen = strlen(str);
+    *needed += len;
+
+    if (*remain == 0)
+        return;
+
+    if(*remain < len + 1)
+        len = *remain - 1;
+
+    if(len > 0) {
+        strncpy(*buf, str, len);
+        *buf += len;
+        *remain -= len;
+    }
+
+    if(len < olen && *remain == 1) {
+        **buf = '\0';
+        ++*buf;
+        --*remain;
+    }
+}
+
+static void put_num(int val, char **buf, size_t *remain, size_t *needed)
+{
+    int tmpval = val;
+    size_t len = 1;
+
+    for (; tmpval > 9; len++, tmpval /= 10);
+
+    *needed += len;
+
+    if (*remain == 0)
+        return;
+
+    BIO_snprintf(*buf, *remain, "%d", val);
+    if (*remain < len) {
+        *buf += *remain;
+        *remain = 0;
+    } else {
+        *buf += len;
+        *remain -= len;
+    }
+}
+
+size_t ossl_property_list_to_string(OSSL_LIB_CTX *ctx,
+                                    const OSSL_PROPERTY_LIST *list, char *buf,
+                                    size_t bufsize)
+{
+    int i;
+    const PROPERTY_DEFINITION *prop = NULL;
+    size_t needed = 0;
+    const char *val;
+
+    if (list == NULL) {
+        if (bufsize > 0)
+            *buf = '\0';
+        return 1;
+    }
+    if (list->n != 0)
+        prop = &list->properties[list->n - 1];
+    for (i = 0; i < list->n; i++, prop--) {
+        /* Skip invalid names */
+        if (prop->name_idx == 0)
+            continue;
+
+        if (needed > 0)
+            put_char(',', &buf, &bufsize, &needed);
+
+        if (prop->optional)
+            put_char('?', &buf, &bufsize, &needed);
+        else if (prop->oper == PROPERTY_OVERRIDE)
+            put_char('-', &buf, &bufsize, &needed);
+
+        val = ossl_property_name_str(ctx, prop->name_idx);
+        if (val == NULL)
+            return 0;
+        put_str(val, &buf, &bufsize, &needed);
+
+        switch (prop->oper) {
+            case PROPERTY_OPER_NE:
+                put_char('!', &buf, &bufsize, &needed);
+                /* fall through */
+            case PROPERTY_OPER_EQ:
+                put_char('=', &buf, &bufsize, &needed);
+                /* put value */
+                switch (prop->type) {
+                case PROPERTY_TYPE_STRING:
+                    val = ossl_property_value_str(ctx, prop->v.str_val);
+                    if (val == NULL)
+                        return 0;
+                    put_str(val, &buf, &bufsize, &needed);
+                    break;
+
+                case PROPERTY_TYPE_NUMBER:
+                    put_num(prop->v.int_val, &buf, &bufsize, &needed);
+                    break;
+
+                default:
+                    return 0;
+                }
+                break;
+            default:
+                /* do nothing */
+                break;
+        }
+    }
+
+    put_char('\0', &buf, &bufsize, &needed);
+    return needed;
+}
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);
+}