ctdb/libctdb/messages.c

   1 /*
   2    core of libctdb
   3
   4    Copyright (C) Rusty Russell 2010
   5
   6    This program is free software; you can redistribute it and/or modify
   7    it under the terms of the GNU General Public License as published by
   8    the Free Software Foundation; either version 3 of the License, or
   9    (at your option) any later version.
  10
  11    This program is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this program; if not, see <http://www.gnu.org/licenses/>.
  18 */
  19
  20 #include "libctdb_private.h"
  21 #include "messages.h"
  22 #include "io_elem.h"
  23 #include <ctdb.h>
  24 #include <tdb.h>
  25 #include <ctdb_protocol.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 #include <errno.h>
  29
  30 /* Remove type-safety macros. */
  31 #undef ctdb_set_message_handler_send
  32 #undef ctdb_set_message_handler_recv
  33 #undef ctdb_remove_message_handler_send
  34
  35 struct message_handler_info {
  36         struct message_handler_info *next, *prev;
  37
  38         uint64_t srvid;
  39         ctdb_message_fn_t handler;
  40         void *handler_data;
  41 };
  42
  43 void deliver_message(struct ctdb_connection *ctdb, struct ctdb_req_header *hdr)
  44 {
  45         struct message_handler_info *i;
  46         struct ctdb_req_message *msg = (struct ctdb_req_message *)hdr;
  47         TDB_DATA data;
  48         bool found;
  49
  50         data.dptr = msg->data;
  51         data.dsize = msg->datalen;
  52
  53         /* Note: we want to call *every* handler: there may be more than one */
  54         for (i = ctdb->message_handlers; i; i = i->next) {
  55                 if (i->srvid == msg->srvid) {
  56                         i->handler(ctdb, msg->srvid, data, i->handler_data);
  57                         found = true;
  58                 }
  59         }
  60         if (!found) {
  61                 DEBUG(ctdb, LOG_WARNING,
  62                       "ctdb_service: messsage for unregistered srvid %llu",
  63                       (unsigned long long)msg->srvid);
  64         }
  65 }
  66
  67 void remove_message_handlers(struct ctdb_connection *ctdb)
  68 {
  69         struct message_handler_info *i;
  70
  71         /* ctdbd should unregister automatically when we close fd, so we don't
  72            need to do that here. */
  73         while ((i = ctdb->message_handlers) != NULL) {
  74                 DLIST_REMOVE(ctdb->message_handlers, i);
  75                 free(i);
  76         }
  77 }
  78
  79 static void free_info(struct ctdb_connection *ctdb, struct ctdb_request *req);
  80
  81 struct ctdb_request *
  82 ctdb_set_message_handler_send(struct ctdb_connection *ctdb, uint64_t srvid,
  83                               ctdb_message_fn_t handler, void *handler_data,
  84                               ctdb_callback_t callback, void *private_data)
  85 {
  86         struct message_handler_info *info;
  87         struct ctdb_request *req;
  88
  89         info = malloc(sizeof(*info));
  90         if (!info) {
  91                 DEBUG(ctdb, LOG_ERR,
  92                       "ctdb_set_message_handler_send: allocating info");
  93                 return NULL;
  94         }
  95
  96         req = new_ctdb_control_request(ctdb, CTDB_CONTROL_REGISTER_SRVID,
  97                                        CTDB_CURRENT_NODE, NULL, 0,
  98                                        callback, private_data);
  99         if (!req) {
 100                 DEBUG(ctdb, LOG_ERR,
 101                       "ctdb_set_message_handler_send: allocating request");
 102                 free(info);
 103                 return NULL;
 104         }
 105         req->extra = info;
 106         req->extra_destructor = free_info;
 107         req->hdr.control->srvid = srvid;
 108
 109         info->srvid = srvid;
 110         info->handler = handler;
 111         info->handler_data = handler_data;
 112
 113         DEBUG(ctdb, LOG_DEBUG,
 114               "ctdb_set_message_handler_send: sending request %u for id %llx",
 115               req->hdr.hdr->reqid, (unsigned long long)srvid);
 116         return req;
 117 }
 118
 119 static void free_info(struct ctdb_connection *ctdb, struct ctdb_request *req)
 120 {
 121         free(req->extra);
 122 }
 123
 124 bool ctdb_set_message_handler_recv(struct ctdb_connection *ctdb,
 125                                    struct ctdb_request *req)
 126 {
 127         struct message_handler_info *info = req->extra;
 128         struct ctdb_reply_control *reply;
 129
 130         reply = unpack_reply_control(req, CTDB_CONTROL_REGISTER_SRVID);
 131         if (!reply) {
 132                 return false;
 133         }
 134         if (reply->status != 0) {
 135                 DEBUG(ctdb, LOG_ERR,
 136                       "ctdb_set_message_handler_recv: status %i",
 137                       reply->status);
 138                 return false;
 139         }
 140
 141         /* Put ourselves in list of handlers. */
 142         DLIST_ADD(ctdb->message_handlers, info);
 143         /* Keep safe from destructor */
 144         req->extra = NULL;
 145         return true;
 146 }
 147
 148 struct ctdb_request *
 149 ctdb_remove_message_handler_send(struct ctdb_connection *ctdb, uint64_t srvid,
 150                                  ctdb_message_fn_t handler, void *hdata,
 151                                  ctdb_callback_t callback, void *cbdata)
 152 {
 153         struct message_handler_info *i;
 154         struct ctdb_request *req;
 155
 156         for (i = ctdb->message_handlers; i; i = i->next) {
 157                 if (i->srvid == srvid
 158                     && i->handler == handler && i->handler_data == hdata) {
 159                         break;
 160                 }
 161         }
 162         if (!i) {
 163                 DEBUG(ctdb, LOG_ALERT,
 164                       "ctdb_remove_message_handler_send: no such handler");
 165                 errno = ENOENT;
 166                 return NULL;
 167         }
 168
 169         req = new_ctdb_control_request(ctdb, CTDB_CONTROL_DEREGISTER_SRVID,
 170                                        CTDB_CURRENT_NODE, NULL, 0,
 171                                        callback, cbdata);
 172         if (!req) {
 173                 DEBUG(ctdb, LOG_ERR,
 174                       "ctdb_remove_message_handler_send: allocating request");
 175                 return NULL;
 176         }
 177         req->hdr.control->srvid = srvid;
 178         req->extra = i;
 179
 180         DEBUG(ctdb, LOG_DEBUG,
 181               "ctdb_set_remove_handler_send: sending request %u for id %llu",
 182               req->hdr.hdr->reqid, (unsigned long long)srvid);
 183         return req;
 184 }
 185
 186 bool ctdb_remove_message_handler_recv(struct ctdb_connection *ctdb,
 187                                       struct ctdb_request *req)
 188 {
 189         struct message_handler_info *handler = req->extra;
 190         struct ctdb_reply_control *reply;
 191
 192         reply = unpack_reply_control(req, CTDB_CONTROL_DEREGISTER_SRVID);
 193         if (!reply) {
 194                 return false;
 195         }
 196         if (reply->status != 0) {
 197                 DEBUG(ctdb, LOG_ERR,
 198                       "ctdb_remove_message_handler_recv: status %i",
 199                       reply->status);
 200                 return false;
 201         }
 202
 203         /* Remove ourselves from list of handlers. */
 204         DLIST_REMOVE(ctdb->message_handlers, handler);
 205         free(handler);
 206         /* Crash if they call this again! */
 207         req->extra = NULL;
 208         return true;
 209 }
 210
 211 bool ctdb_send_message(struct ctdb_connection *ctdb,
 212                       uint32_t pnn, uint64_t srvid,
 213                       TDB_DATA data)
 214 {
 215         struct ctdb_request *req;
 216         struct ctdb_req_message *pkt;
 217
 218         /* We just discard it once it's finished: no reply. */
 219         req = new_ctdb_request(
 220                 ctdb, offsetof(struct ctdb_req_message, data) + data.dsize,
 221                 ctdb_cancel_callback, NULL);
 222         if (!req) {
 223                 DEBUG(ctdb, LOG_ERR, "ctdb_set_message: allocating message");
 224                 return false;
 225         }
 226
 227         io_elem_init_req_header(req->io,
 228                                 CTDB_REQ_MESSAGE, pnn, new_reqid(ctdb));
 229
 230         pkt = req->hdr.message;
 231         pkt->srvid = srvid;
 232         pkt->datalen = data.dsize;
 233         memcpy(pkt->data, data.dptr, data.dsize);
 234         DLIST_ADD_END(ctdb->outq, req, struct ctdb_request);
 235         return true;
 236 }