Add a way to report rpc-errors from a plugin

Add plugin_rpc_err(), which works something like clixon_err, but it
saves error information from a plugin for reporting rpc-errors that
need to be returned.

Signed-off-by: Corey Minyard <corey@minyard.net>

apps/backend/backend_client.c

@@ -711,8 +711,14 @@ from_client_edit_config(clixon_handle h,
             }
         }
         if ((ret = candidate_commit(h, NULL, "candidate", myid, 0, cbret)) < 0){ /* Assume validation fail, nofatal */
-            if (netconf_operation_failed(cbret, "application", clixon_err_reason())< 0)
-                goto done;
+	    if (clixon_err_category()) {
+		if (netconf_operation_failed(cbret, "application",
+					     clixon_err_reason()) < 0)
+		    goto done;
+	    } else if (plugin_rpc_err_set()) {
+		if (netconf_gen_rpc_err(cbret) < 0)
+		    goto done;
+	    }
             xmldb_copy(h, "running", "candidate");
             goto ok;
         }

apps/backend/backend_commit.c

@@ -596,6 +596,138 @@ validate_common(clixon_handle       h,
     goto done;
 }
 
+static char *_plugin_rpc_err_ns;
+static char *_plugin_rpc_err_type;
+static char *_plugin_rpc_err_tag;
+static char *_plugin_rpc_err_info;
+static char *_plugin_rpc_err_severity;
+static cbuf *_plugin_rpc_err_message;
+
+/*! Save an RPC error to be reported by clixon.
+ *
+ * @param[in]  h        Clixon
+ * @param[in]  ns       Namespace.  If NULL the netconf base ns will be used
+ * @param[in]  type     Error type: "rpc", "application" or "protocol"
+ * @param[in]  severity Severity: "error" or "warning"
+ * @param[in]  tag      Error tag, like "invalid-value" or "unknown-attribute"
+ * @param[in]  info     bad-attribute or bad-element xml.  If NULL not included.
+ * @param[in]  fmt      Error message format.  May be NULL.
+ * @retval     0        Success
+ * @retval    -1        Error
+ */
+int
+plugin_rpc_err(clixon_handle h, const char *ns,
+	       const char *type, const char *tag, const char *info,
+	       const char *severity,
+	       const char *fmt, ...)
+{
+    char *n_ns = NULL, *n_type = NULL, *n_tag = NULL;
+    char *n_info = NULL, *n_severity = NULL;
+    cbuf *n_message = NULL;
+    int err;
+
+    if (ns) {
+	n_ns = strdup(ns);
+	if (!n_ns)
+	    goto out_nomem;
+    }
+    n_type = strdup(type);
+    if (!n_type)
+	goto out_nomem;
+    n_tag = strdup(tag);
+    if (!n_tag)
+	goto out_nomem;
+    if (ns) {
+	n_ns = strdup(ns);
+	if (!n_ns)
+	    goto out_nomem;
+    }
+    if (info) {
+	n_info = strdup(info);
+	if (!n_info)
+	    goto out_nomem;
+    }
+    n_severity = strdup(severity);
+    if (!n_severity)
+	goto out_nomem;
+    if (fmt) {
+	va_list args;
+	n_message = cbuf_new();
+	if (!n_message)
+	    goto out_nomem;
+	va_start(args, fmt);
+	err = vcprintf(n_message, fmt, args);
+	va_end(args);
+	if (err < 0)
+	    goto out_nomem;
+    }
+    /*
+     * Everything is allocated, we cannot fail from here, so clean up the
+     * old stuff.
+     */
+    if (_plugin_rpc_err_ns)
+	free(_plugin_rpc_err_ns);
+    if (_plugin_rpc_err_type)
+	free(_plugin_rpc_err_type);
+    if (_plugin_rpc_err_tag)
+	free(_plugin_rpc_err_tag);
+    if (_plugin_rpc_err_info)
+	free(_plugin_rpc_err_info);
+    if (_plugin_rpc_err_severity)
+	free(_plugin_rpc_err_severity);
+    if (_plugin_rpc_err_message)
+	cbuf_free(_plugin_rpc_err_message);
+
+    _plugin_rpc_err_ns = n_ns;
+    _plugin_rpc_err_type = n_type;
+    _plugin_rpc_err_tag = n_tag;
+    _plugin_rpc_err_info = n_info;
+    _plugin_rpc_err_severity = n_severity;
+    _plugin_rpc_err_message = n_message;
+    return 0;
+
+ out_nomem:
+    if (n_ns)
+	free(n_ns);
+    if (n_type)
+	free(n_type);
+    if (n_tag)
+	free(n_tag);
+    if (n_info)
+	free(n_info);
+    if (n_severity)
+	free(n_severity);
+    if (n_message)
+	cbuf_free(n_message);
+    return -1;
+}
+
+int
+plugin_rpc_err_set(void)
+{
+    return _plugin_rpc_err_type != NULL;
+}
+
+int
+netconf_gen_rpc_err(cbuf *cbret)
+{
+    char *type = _plugin_rpc_err_type;
+    int ret;
+
+    /* Type marks it as set, clear it before handling. */
+    _plugin_rpc_err_type = NULL;
+    ret = netconf_common_rpc_err(cbret, _plugin_rpc_err_ns,
+				 type,
+				 _plugin_rpc_err_tag,
+				 _plugin_rpc_err_severity,
+				 _plugin_rpc_err_info,
+				 cbuf_get(_plugin_rpc_err_message));
+    free(type);
+
+    return ret;
+}
+
+
 /*! Start a validate transaction
  *
  * @param[in]  h      Clixon handle
@@ -630,9 +762,16 @@ candidate_validate(clixon_handle h,
          * use clixon_err. 
          * TODO: -1 return should be fatal error, not failed validation
          */
-        if (!cbuf_len(cbret) &&
-            netconf_operation_failed(cbret, "application", clixon_err_reason())< 0)
-            goto done;
+        if (!cbuf_len(cbret))
+	    goto done;
+	if (clixon_err_category()) {
+	    if (netconf_operation_failed(cbret, "application",
+					 clixon_err_reason()) < 0)
+		goto done;
+	} else if (plugin_rpc_err_set()) {
+	    if (netconf_gen_rpc_err(cbret) < 0)
+		goto done;
+	}
         goto fail;
     }
     if (ret == 0){
@@ -844,9 +983,16 @@ from_client_commit(clixon_handle h,
     }
     if ((ret = candidate_commit(h, xe, "candidate", myid, 0, cbret)) < 0){ /* Assume validation fail, nofatal */
         clixon_debug(CLIXON_DBG_BACKEND, "Commit candidate failed");
-        if (ret < 0)
-            if (netconf_operation_failed(cbret, "application", clixon_err_reason())< 0)
-                goto done;
+        if (ret < 0) {
+	    if (clixon_err_category()) {
+		if (netconf_operation_failed(cbret, "application",
+					     clixon_err_reason()) < 0)
+		    goto done;
+	    } else if (plugin_rpc_err_set()) {
+		if (netconf_gen_rpc_err(cbret) < 0)
+		    goto done;
+	    }
+	}
         goto ok;
     }
     if (clicon_option_bool(h, "CLICON_AUTOLOCK"))

apps/backend/backend_plugin.c

@@ -629,8 +629,9 @@ plugin_transaction_call_one(clixon_handle       h,
     if (clixon_resource_check(h, &wh, clixon_plugin_name_get(cp), fnname) < 0)
         goto done;
     if (rv < 0) {
-        if (!clixon_err_category()) /* sanity: log if clixon_err() is not called ! */
-            clixon_log(h, LOG_NOTICE, "%s: Plugin '%s' callback does not make clixon_err call on error",
+        if (!plugin_rpc_err_set() && !clixon_err_category())
+	    /* sanity: log if err is not called ! */
+            clixon_log(h, LOG_NOTICE, "%s: Plugin '%s' callback does not make clixon_err or plugin_rpc_err call on error",
                        fnname, clixon_plugin_name_get(cp));
         goto done;
     }

apps/backend/clixon_backend_plugin.h

@@ -133,4 +133,10 @@ int plugin_transaction_end_all(clixon_handle h, transaction_data_t *td);
 int plugin_transaction_abort_one(clixon_plugin_t *cp, clixon_handle h, transaction_data_t *td);
 int plugin_transaction_abort_all(clixon_handle h, transaction_data_t *td);
 
+int plugin_rpc_err(clixon_handle h, const char *ns,
+		   const char *type, const char *tag, const char *info,
+		   const char *severity, const char *fmt, ...);
+int plugin_rpc_err_set(void);
+int netconf_gen_rpc_err(cbuf *cbret);
+
 #endif  /* _CLIXON_BACKEND_PLUGIN_H_ */

lib/clixon/clixon_netconf_lib.h

@@ -161,6 +161,8 @@ int netconf_missing_attribute_xml(cxobj **xret, char *type, char *info, char *me
 int netconf_bad_attribute(cbuf *cb, char *type, char *info, char *message);
 int netconf_bad_attribute_xml(cxobj **xret, char *type, char *info, char *message);
 int netconf_unknown_attribute(cbuf *cb, char *type, char *info, char *message);
+int netconf_common_rpc_err(cbuf *cb, char *ns, char *type, char *tag, char *info,
+			   char *severity, char *message);
 int netconf_missing_element(cbuf *cb, char *type, char *element, char *message);
 int netconf_missing_yang_xml(cxobj **xret, char *path, char *app_tag, char *info, char *message);
 int netconf_missing_element_xml(cxobj **xret, char *type, char *element, char *message);

lib/src/clixon_netconf_lib.c

@@ -487,6 +487,62 @@ netconf_unknown_attribute(cbuf *cb,
     goto done;
 }
 
+/*! Create Netconf rpc-error XML tree with all parameters available.
+ *
+ * An unexpected attribute is present.
+ * @param[out] cb       CLIgen buf. Error XML is written in this buffer
+ * @param[in]  ns       Namespace.  If NULL the netconf base ns will be used
+ * @param[in]  type     Error type: "rpc", "application" or "protocol"
+ * @param[in]  severity Severity: "error" or "warning"
+ * @param[in]  tag      Error tag, like "invalid-value" or "unknown-attribute"
+ * @param[in]  info     bad-attribute or bad-element xml.  If NULL not included.
+ * @param[in]  message  Error message.  May be NULL.
+ * @retval     0        OK
+ * @retval    -1        Error
+ */
+int
+netconf_common_rpc_err(cbuf *cb,
+		       char *ns,
+		       char *type,
+		       char *tag,
+		       char *severity,
+		       char *info,
+		       char *message)
+{
+    int   retval = -1;
+    char *encstr = NULL;
+
+    if (!ns)
+	ns = NETCONF_BASE_NAMESPACE;
+
+    if (cprintf(cb, "<rpc-reply xmlns=\"%s\"><rpc-error>"
+                "<error-type>%s</error-type>"
+                "<error-tag>%s</error-tag>"
+                "<error-severity>%s</error-severity>",
+                ns, type, tag, severity) < 0)
+        goto err;
+    if (info){
+        if (cprintf(cb, "<error-info>%s</error-info>", info) < 0)
+            goto err;
+    }
+    if (message){
+        if (xml_chardata_encode(&encstr, 0, "%s", message) < 0)
+            goto done;
+        if (cprintf(cb, "<error-message>%s</error-message>", encstr) < 0)
+            goto err;
+    }
+    if (cprintf(cb, "</rpc-error></rpc-reply>") < 0)
+        goto err;
+    retval = 0;
+ done:
+    if (encstr)
+        free(encstr);
+    return retval;
+ err:
+    clixon_err(OE_XML, errno, "cprintf");
+    goto done;
+}
+
 /*! Common Netconf element XML tree according to RFC 6241 App A
  *
  * @param[out] xret    Error XML tree. Free with xml_free after use