X-Git-Url: http://www.project-moonshot.org/gitweb/?p=trust_router.git;a=blobdiff_plain;f=mon%2Fmons_handlers.c;fp=mon%2Fmons_handlers.c;h=24cce1f9479ac5f7b2b3147a0f8a112b2cb9708f;hp=0000000000000000000000000000000000000000;hb=6f65c9cce86719147d0b4dcc9823b25443c2d185;hpb=eaa1a8ceed54fbfadc2638cf383aaa12ab446a57 diff --git a/mon/mons_handlers.c b/mon/mons_handlers.c new file mode 100644 index 0000000..24cce1f --- /dev/null +++ b/mon/mons_handlers.c @@ -0,0 +1,259 @@ +/* + * 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 + +#include +#include +#include + + +/* 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); + } +} +