/* * table_iterator.c */ /** @defgroup table_iterator table_iterator: The table iterator helper is designed to simplify the task of writing a table handler for the net-snmp agent when the data being accessed is not in an oid sorted form and must be accessed externally. * @ingroup table * Functionally, it is a specialized version of the more * generic table helper but easies the burden of GETNEXT processing by * manually looping through all the data indexes retrieved through * function calls which should be supplied by the module that wishes * help. The module the table_iterator helps should, afterwards, * never be called for the case of "MODE_GETNEXT" and only for the GET * and SET related modes instead. */ #include #if HAVE_STRING_H #include #else #include #endif #include #include #include #include #include #if HAVE_DMALLOC_H #include #endif /* * doesn't work yet, but shouldn't be serialized (for efficiency) */ #undef NOT_SERIALIZED #define TABLE_ITERATOR_LAST_CONTEXT "ti_last_c" /** returns a netsnmp_mib_handler object for the table_iterator helper */ netsnmp_mib_handler * netsnmp_get_table_iterator_handler(netsnmp_iterator_info *iinfo) { netsnmp_mib_handler *me = netsnmp_create_handler(TABLE_ITERATOR_NAME, netsnmp_table_iterator_helper_handler); if (!me || !iinfo) return NULL; me->myvoid = iinfo; return me; } /** registers a table after attaching it to a table_iterator helper */ int netsnmp_register_table_iterator(netsnmp_handler_registration *reginfo, netsnmp_iterator_info *iinfo) { netsnmp_inject_handler(reginfo, netsnmp_get_table_iterator_handler(iinfo)); if (!iinfo) return SNMPERR_GENERR; #ifndef NOT_SERIALIZED netsnmp_inject_handler(reginfo, netsnmp_get_serialize_handler()); #endif return netsnmp_register_table(reginfo, iinfo->table_reginfo); } /** extracts the table_iterator specific data from a request */ NETSNMP_INLINE void * netsnmp_extract_iterator_context(netsnmp_request_info *request) { return netsnmp_request_get_list_data(request, TABLE_ITERATOR_NAME); } /** implements the table_iterator helper */ int netsnmp_table_iterator_helper_handler(netsnmp_mib_handler *handler, netsnmp_handler_registration *reginfo, netsnmp_agent_request_info *reqinfo, netsnmp_request_info *requests) { netsnmp_table_registration_info *tbl_info; oid coloid[MAX_OID_LEN]; size_t coloid_len; int ret; static oid myname[MAX_OID_LEN]; static int myname_len; int oldmode; netsnmp_iterator_info *iinfo; iinfo = (netsnmp_iterator_info *) handler->myvoid; if (!iinfo || !reginfo || !reqinfo) return SNMPERR_GENERR; tbl_info = iinfo->table_reginfo; /* * copy in the table registration oid for later use */ coloid_len = reginfo->rootoid_len + 2; memcpy(coloid, reginfo->rootoid, reginfo->rootoid_len * sizeof(oid)); coloid[reginfo->rootoid_len] = 1; /* table.entry node */ /* * illegally got here if these functions aren't defined */ if (iinfo->get_first_data_point == NULL || iinfo->get_next_data_point == NULL) { snmp_log(LOG_ERR, "table_iterator helper called without data accessor functions\n"); return SNMP_ERR_GENERR; } /* * XXXWWW: deal with SET caching */ #ifdef NOT_SERIALIZED while (requests) /* XXX: currently only serialized */ #endif { /* * XXXWWW: optimize by reversing loops (look through data only once) */ netsnmp_variable_list *results = NULL; netsnmp_variable_list *index_search = NULL; /* WWW: move up? */ netsnmp_variable_list *free_this_index_search = NULL; netsnmp_table_request_info *table_info = netsnmp_extract_table_info(requests); void *callback_loop_context = NULL; void *callback_data_context = NULL; void *callback_data_keep = NULL; if (requests->processed != 0) { #ifdef NOT_SERIALIZED continue; #else return SNMP_ERR_NOERROR; #endif } if (reqinfo->mode != MODE_GET && reqinfo->mode != MODE_GETNEXT && reqinfo->mode != MODE_GETBULK && /* XXX */ reqinfo->mode != MODE_SET_RESERVE1) { goto skip_processing; } if (table_info->colnum > tbl_info->max_column) { requests->processed = 1; #ifdef NOT_SERIALIZED break; #else return SNMP_ERR_NOERROR; #endif } /* * XXX: if loop through everything, these are never free'd * since iterator returns NULL and thus we forget about * these */ index_search = snmp_clone_varbind(table_info->indexes); if (!index_search) { /* * hmmm.... invalid table? */ snmp_log(LOG_WARNING, "invalid index list or failed malloc for table %s\n", reginfo->handlerName); return SNMP_ERR_NOERROR; } free_this_index_search = index_search; /* * below our minimum column? */ if (table_info->colnum < tbl_info->min_column) { results = (iinfo->get_first_data_point) (&callback_loop_context, &callback_data_context, index_search, iinfo); if (iinfo->free_loop_context) { (iinfo->free_loop_context) (callback_loop_context, iinfo); callback_loop_context = NULL; } goto got_results; } /* * XXX: do "only got some indexes" */ /* * find the next legal result to return */ /* * find the first node */ index_search = (iinfo->get_first_data_point) (&callback_loop_context, &callback_data_context, index_search, iinfo); /* * table.entry.column node */ coloid[reginfo->rootoid_len + 1] = table_info->colnum; switch (reqinfo->mode) { case MODE_GETNEXT: case MODE_GETBULK: /* XXXWWW */ /* * loop through all data and find next one */ while (index_search) { /* * compare the node with previous results */ if (netsnmp_check_getnext_reply (requests, coloid, coloid_len, index_search, &results)) { /* * result is our current choice, so keep a pointer to * the data that the lower handler wants us to * remember (possibly freeing the last known "good" * result data pointer) */ if (callback_data_keep && iinfo->free_data_context) { (iinfo->free_data_context) (callback_data_keep, iinfo); callback_data_keep = NULL; } if (iinfo->make_data_context && !callback_data_context) { callback_data_context = (iinfo-> make_data_context) (callback_loop_context, iinfo); } callback_data_keep = callback_data_context; callback_data_context = NULL; } else { if (callback_data_context && iinfo->free_data_context) (iinfo->free_data_context) (callback_data_context, iinfo); callback_data_context = NULL; } /* * get the next node in the data chain */ index_search = (iinfo->get_next_data_point) (&callback_loop_context, &callback_data_context, index_search, iinfo); if (!index_search && !results && tbl_info->max_column > table_info->colnum) { /* * restart loop. XXX: Should cache this better */ table_info->colnum++; coloid[reginfo->rootoid_len + 1] = table_info->colnum; if (free_this_index_search != NULL) snmp_free_varbind(free_this_index_search); index_search = snmp_clone_varbind(table_info->indexes); free_this_index_search = index_search; if (callback_loop_context && iinfo->free_loop_context_at_end) { (iinfo->free_loop_context_at_end)(callback_loop_context, iinfo); callback_loop_context = NULL; } if (iinfo->free_loop_context && callback_loop_context) { (iinfo->free_loop_context) (callback_loop_context, iinfo); callback_loop_context = NULL; } if (callback_data_context && iinfo->free_data_context) { (iinfo->free_data_context) (callback_data_context, iinfo); callback_data_context = NULL; } index_search = (iinfo-> get_first_data_point) (&callback_loop_context, &callback_data_context, index_search, iinfo); } } break; case MODE_GET: case MODE_SET_RESERVE1: /* * loop through all data till exact results are found */ while (index_search) { build_oid_noalloc(myname, MAX_OID_LEN, &myname_len, coloid, coloid_len, index_search); if (snmp_oid_compare(myname, myname_len, requests->requestvb->name, requests->requestvb->name_length) == 0) { /* * found the exact match, so we're done */ if (iinfo->make_data_context && !callback_data_context) { callback_data_context = (iinfo-> make_data_context) (callback_loop_context, iinfo); } callback_data_keep = callback_data_context; callback_data_context = NULL; results = snmp_clone_varbind(index_search); snmp_set_var_objid(results, myname, myname_len); goto got_results; } else { /* * free not-needed data context */ if (callback_data_context && iinfo->free_data_context) { (iinfo->free_data_context) (callback_data_context, iinfo); callback_data_context = NULL; } } /* * get the next node in the data chain */ index_search = (iinfo->get_next_data_point) (&callback_loop_context, &callback_data_context, index_search, iinfo); } break; default: /* * the rest of the set states have been dealt with already */ goto got_results; } /* * XXX: free index_search? */ if (callback_loop_context && iinfo->free_loop_context) { (iinfo->free_loop_context) (callback_loop_context, iinfo); callback_loop_context = NULL; } got_results: /* not milk */ /* * This free_data_context call is required in the event that your * get_next_data_point method allocates new memory, even during the * calls where it eventually returns a NULL */ if (callback_data_context && iinfo->free_data_context) { (iinfo->free_data_context) (callback_data_context, iinfo); callback_data_context = NULL; } if (!results && !MODE_IS_SET(reqinfo->mode)) { /* * no results found. */ /* * XXX: check for at least one entry at the very top */ #ifdef NOT_SERIALIZED break; #else if (callback_loop_context && iinfo->free_loop_context_at_end) { (iinfo->free_loop_context_at_end) (callback_loop_context, iinfo); callback_loop_context = NULL; } if (free_this_index_search != NULL) { snmp_free_varbind(free_this_index_search); } return SNMP_ERR_NOERROR; #endif } skip_processing: /* * OK, here results should be a pointer to the data that we * actually need to GET */ oldmode = reqinfo->mode; if (reqinfo->mode == MODE_GETNEXT || reqinfo->mode == MODE_GETBULK) { /* XXX */ snmp_set_var_objid(requests->requestvb, results->name, results->name_length); reqinfo->mode = MODE_GET; } if (reqinfo->mode == MODE_GET || reqinfo->mode == MODE_GETNEXT || reqinfo->mode == MODE_GETBULK || /* XXX */ reqinfo->mode == MODE_SET_RESERVE1) { /* * first (or only) pass stuff */ /* * let set requsets use previously constructed data */ snmp_free_varbind(results); if (callback_data_keep) netsnmp_request_add_list_data(requests, netsnmp_create_data_list (TABLE_ITERATOR_NAME, callback_data_keep, NULL)); netsnmp_request_add_list_data(requests, netsnmp_create_data_list (TABLE_ITERATOR_LAST_CONTEXT, callback_loop_context, NULL)); } DEBUGMSGTL(("table_iterator", "doing mode: %s\n", se_find_label_in_slist("agent_mode", oldmode))); ret = netsnmp_call_next_handler(handler, reginfo, reqinfo, requests); if (oldmode == MODE_GETNEXT || oldmode == MODE_GETBULK) { /* XXX */ if (requests->requestvb->type == ASN_NULL || requests->requestvb->type == SNMP_NOSUCHINSTANCE) { /* * get next skipped this value for this column, we * need to keep searching forward */ requests->requestvb->type = ASN_PRIV_RETRY; } reqinfo->mode = oldmode; } callback_data_keep = netsnmp_request_get_list_data(requests, TABLE_ITERATOR_NAME); callback_loop_context = netsnmp_request_get_list_data(requests, TABLE_ITERATOR_LAST_CONTEXT); /* * This has to be done to prevent a memory leak. Notice that on * SET_RESERVE1 we're assigning something to * 'free_this_index_search' at the beginning of this handler (right * above the line that says 'below our minimum column?'), * but we're not given a chance to free it below with the other * SET modes, hence our doing it here. */ if (reqinfo->mode == MODE_SET_RESERVE1) { if (free_this_index_search) { snmp_free_varbind(free_this_index_search); free_this_index_search = NULL; } } if (reqinfo->mode == MODE_GET || reqinfo->mode == MODE_GETNEXT || reqinfo->mode == MODE_GETBULK || /* XXX */ reqinfo->mode == MODE_SET_FREE || reqinfo->mode == MODE_SET_UNDO || reqinfo->mode == MODE_SET_COMMIT) { if (callback_data_keep && iinfo->free_data_context) { (iinfo->free_data_context) (callback_data_keep, iinfo); callback_data_keep = NULL; } if (free_this_index_search) { snmp_free_varbind(free_this_index_search); free_this_index_search = NULL; } #ifndef NOT_SERIALIZED if (callback_loop_context && iinfo->free_loop_context_at_end) { (iinfo->free_loop_context_at_end) (callback_loop_context, iinfo); callback_loop_context = NULL; } #endif } #ifdef NOT_SERIALIZED return ret; #else requests = requests->next; #endif } #ifdef NOT_SERIALIZED if (reqinfo->mode == MODE_GET || reqinfo->mode == MODE_GETNEXT || reqinfo->mode == MODE_GETBULK || /* XXX */ reqinfo->mode == MODE_SET_FREE || reqinfo->mode == MODE_SET_UNDO || reqinfo->mode == MODE_SET_COMMIT) { if (callback_loop_context && iinfo->free_loop_context_at_end) { (iinfo->free_loop_context_at_end) (callback_loop_context, iinfo); callback_loop_context = NULL; } } #endif return SNMP_ERR_NOERROR; }