+/*
+ * Copyright (c) 2018, JANET(UK)
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * 3. Neither the name of JANET(UK) nor the names of its contributors
+ * may be used to endorse or promote products derived from this software
+ * without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
+ * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
+ * OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+/* Handlers for monitoring requests */
+
+#include <glib.h>
+
+#include <tr_debug.h>
+#include <mon_internal.h>
+#include <mons_handlers.h>
+
+
+/* Static Prototypes */
+static int dispatch_entry_matches(MONS_DISPATCH_TABLE_ENTRY *e, MON_CMD command, MON_OPT_TYPE opt_type);
+static MONS_HANDLER_FUNC *mons_find_handler(MONS_INSTANCE *mons, MON_CMD cmd, MON_OPT_TYPE opt_type);
+static void request_helper(void *element, void *data);
+
+struct request_helper_data {
+ MON_CMD command;
+ MON_OPT_TYPE opt_type;
+ json_t *payload; /* json object to add responses to */
+ GArray *results;
+};
+
+struct handler_result {
+ MON_OPT_TYPE opt_type; /* what opt type set this? */
+ MON_RC rc; /* what was its result code? */
+ json_t *json_data; /* what data, if any, is it returning? */
+};
+
+/**
+ * Call the appropriate handler for a request
+ *
+ * TODO: report errors from handlers
+ *
+ * @return a MON_RESP structure or null if there was a processing error
+ */
+MON_RESP *mons_handle_request(TALLOC_CTX *mem_ctx, MONS_INSTANCE *mons, MON_REQ *req)
+{
+ MON_RESP *resp = NULL;
+ json_t *payload = NULL;
+ struct request_helper_data cookie = {0};
+ size_t ii = 0;
+
+ tr_debug("mons_handle_request: Handling a request");
+
+ /* Start off by allocating our response with a generic error message */
+ resp = mon_resp_new(mem_ctx,
+ MON_RESP_ERROR,
+ "error processing request",
+ NULL);
+ if (resp == NULL) {
+ /* we can't respond, just return */
+ tr_crit("mons_handle_request: Error allocating response structure.");
+ goto cleanup;
+ }
+
+ /* Now get a JSON object for our return payload */
+ payload = json_object();
+ if (payload == NULL) {
+ tr_crit("mons_handle_request: Error allocating response payload.");
+ goto cleanup; /* This will return the generic error message set earlier */
+ }
+
+ /* Now call handlers */
+ cookie.command = req->command;
+ cookie.results = g_array_new(FALSE, TRUE, sizeof(struct handler_result));
+
+ if (mon_req_opt_count(req) == 0) {
+ /* call every handler that matches the command */
+ cookie.opt_type = OPT_TYPE_ANY;
+ g_ptr_array_foreach(mons->handlers, request_helper, &cookie);
+ } else {
+ /* call only those handlers that match an option */
+ for (ii=0; ii < mon_req_opt_count(req); ii++) {
+ cookie.opt_type = mon_req_opt_index(req, ii)->type;
+ /* Loop over all handlers - we know we can only have one match for each opt type */
+ g_ptr_array_foreach(mons->handlers, request_helper, &cookie);
+ }
+ }
+
+ /* We now have an array of results in cookie.results. If any of these failed, return an error. */
+ tr_debug("mons_handle_request: Examining %d handler results", cookie.results->len);
+ resp->code = MON_RESP_SUCCESS; /* tentatively set this to success */
+ for (ii=0; ii < cookie.results->len; ii++) {
+ struct handler_result *this = &g_array_index(cookie.results, struct handler_result, ii);
+ if (this->rc != MON_SUCCESS) {
+ tr_debug("mons_handle_request: Result %d was an error.", ii);
+ resp->code = MON_RESP_ERROR;
+ }
+
+ /* add the JSON response even if there was an error */
+ if (this->json_data) {
+ tr_debug("mons_handle_request: Result %d returned JSON data.", ii);
+ json_object_set_new(payload, mon_opt_type_to_string(this->opt_type), this->json_data);
+ }
+ }
+
+ if (resp->code == MON_RESP_SUCCESS) {
+ if (mon_resp_set_message(resp, "success") == 0) {
+ /* Failed to set the response message to success - fail ironically, don't send
+ * an inconsistent response. */
+ tr_crit("mons_handle_request: Error setting response message to 'success'.");
+ goto cleanup;
+ }
+ } else {
+ /* Failed - send a response indicating that the overall command succeeded */
+ if (mon_resp_set_message(resp, "request processed but an error occurred") == 0) {
+ tr_crit("mons_handle_request: Error setting response message after a handler error.");
+ goto cleanup;
+ }
+ }
+
+ /* Attach the accumulated payload to the response */
+ if (json_object_size(payload) > 0) {
+ tr_debug("mons_handle_request: Attaching payload to response.");
+ mon_resp_set_payload(resp, payload);
+ }
+
+ tr_debug("mons_handle_request: Successfully processed request.");
+
+cleanup:
+ if (payload)
+ json_decref(payload);
+ if (cookie.results)
+ g_array_free(cookie.results, TRUE);
+ return resp;
+}
+
+/**
+ * Register a handler for a command/option combination
+ *
+ * @param mons
+ * @param cmd
+ * @param opt_type
+ * @param f
+ * @param cookie
+ * @return
+ */
+MON_RC mons_register_handler(MONS_INSTANCE *mons,
+ MON_CMD cmd,
+ MON_OPT_TYPE opt_type,
+ MONS_HANDLER_FUNC *f,
+ void *cookie)
+{
+ MONS_DISPATCH_TABLE_ENTRY *entry = NULL;
+
+ if (mons_find_handler(mons, cmd, opt_type) != NULL) {
+ return MON_ERROR;
+ }
+
+ /* Put these in the mons talloc context so we don't have to muck about with
+ * a free function for the GPtrArray */
+ entry = talloc(mons, MONS_DISPATCH_TABLE_ENTRY);
+ if (entry == NULL) {
+ return MON_NOMEM;
+ }
+ entry->command = cmd;
+ entry->opt_type = opt_type;
+ entry->handler = f;
+ entry->cookie = cookie;
+
+ g_ptr_array_add(mons->handlers, entry);
+ return MON_SUCCESS;
+}
+
+/**
+ * Two table entries match if none of the commands or opt_types are unknown,
+ * if the commands match, and if the opt types either match or at least one is
+ * OPT_TYPE_ANY.
+ *
+ * No comparison of the handler pointer is included.
+ *
+ * @return 1 if the two match, 0 if not
+ */
+static int dispatch_entry_matches(MONS_DISPATCH_TABLE_ENTRY *e,
+ MON_CMD command,
+ MON_OPT_TYPE opt_type)
+{
+ if ((command == MON_CMD_UNKNOWN) || (opt_type == OPT_TYPE_UNKNOWN))
+ return 0; /* request is invalid */
+
+ if ((e->command == MON_CMD_UNKNOWN) || (e->opt_type == OPT_TYPE_UNKNOWN))
+ return 0; /* e1 is invalid */
+
+ if (e->command != command)
+ return 0; /* commands do not match */
+
+ if (e->opt_type == opt_type)
+ return 1; /* exact match */
+
+ if ( (e->opt_type == OPT_TYPE_ANY) || (opt_type == OPT_TYPE_ANY) )
+ return 1; /* one is a wildcard */
+
+ return 0; /* commands matched but opt_types did not */
+}
+
+static MONS_HANDLER_FUNC *mons_find_handler(MONS_INSTANCE *mons, MON_CMD cmd, MON_OPT_TYPE opt_type)
+{
+ guint index;
+
+ for (index=0; index < mons->handlers->len; index++) {
+ if (dispatch_entry_matches(g_ptr_array_index(mons->handlers, index), cmd, opt_type))
+ return g_ptr_array_index(mons->handlers, index);
+ }
+ return NULL;
+}
+
+/**
+ * This calls every request handler that matches a command/opt_type,
+ * gathering their results.
+ *
+ * @param element
+ * @param data
+ */
+static void request_helper(void *element, void *data)
+{
+ MONS_DISPATCH_TABLE_ENTRY *entry = talloc_get_type_abort(element, MONS_DISPATCH_TABLE_ENTRY);
+ struct request_helper_data *helper_data = data;
+ struct handler_result result = {0};
+
+ if (dispatch_entry_matches(entry, helper_data->command, helper_data->opt_type)) {
+ result.rc = entry->handler(entry->cookie, &(result.json_data));
+ result.opt_type = entry->opt_type;
+ g_array_append_val(helper_data->results, result);
+ }
+}
+
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