libctdb/sync.c

   1 /*
   2    synchronous wrappers for 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 #include <ctdb.h>
  20 #include <stdbool.h>
  21 #include <poll.h>
  22 #include <errno.h>
  23 #include <stdlib.h>
  24 #include "libctdb_private.h"
  25
  26 /* Remove type-safety macros. */
  27 #undef ctdb_set_message_handler
  28
  29 /* On failure, frees req and returns NULL. */
  30 static struct ctdb_request *synchronous(struct ctdb_connection *ctdb,
  31                                         struct ctdb_request *req,
  32                                         bool *done)
  33 {
  34         struct pollfd fds;
  35
  36         /* Pass through allocation failures. */
  37         if (!req)
  38                 return NULL;
  39
  40         fds.fd = ctdb_get_fd(ctdb);
  41         while (!*done) {
  42                 fds.events = ctdb_which_events(ctdb);
  43                 if (poll(&fds, 1, -1) < 0) {
  44                         /* Signalled is OK, other error is bad. */
  45                         if (errno == EINTR)
  46                                 continue;
  47                         ctdb_cancel(ctdb, req);
  48                         DEBUG(ctdb, LOG_ERR, "ctdb_synchronous: poll failed");
  49                         return NULL;
  50                 }
  51                 if (!ctdb_service(ctdb, fds.revents)) {
  52                         /* It can have failed after it completed request. */
  53                         if (!*done)
  54                                 ctdb_cancel(ctdb, req);
  55                         else
  56                                 ctdb_request_free(req);
  57                         return NULL;
  58                 }
  59         }
  60         return req;
  61 }
  62
  63 static void set(struct ctdb_connection *ctdb,
  64                 struct ctdb_request *req, bool *done)
  65 {
  66         *done = true;
  67 }
  68
  69 bool ctdb_getrecmaster(struct ctdb_connection *ctdb,
  70                        uint32_t destnode, uint32_t *recmaster)
  71 {
  72         struct ctdb_request *req;
  73         bool done = false;
  74         bool ret = false;
  75
  76         req = synchronous(ctdb,
  77                           ctdb_getrecmaster_send(ctdb, destnode, set, &done),
  78                           &done);
  79         if (req != NULL) {
  80                 ret = ctdb_getrecmaster_recv(ctdb, req, recmaster);
  81                 ctdb_request_free(req);
  82         }
  83         return ret;
  84 }
  85
  86 bool ctdb_getrecmode(struct ctdb_connection *ctdb,
  87                        uint32_t destnode, uint32_t *recmode)
  88 {
  89         struct ctdb_request *req;
  90         bool done = false;
  91         bool ret = false;
  92
  93         req = synchronous(ctdb,
  94                           ctdb_getrecmode_send(ctdb, destnode, set, &done),
  95                           &done);
  96         if (req != NULL) {
  97                 ret = ctdb_getrecmode_recv(ctdb, req, recmode);
  98                 ctdb_request_free(req);
  99         }
 100         return ret;
 101 }
 102
 103 struct ctdb_db *ctdb_attachdb(struct ctdb_connection *ctdb,
 104                               const char *name, bool persistent,
 105                               uint32_t tdb_flags)
 106 {
 107         struct ctdb_request *req;
 108         bool done = false;
 109         struct ctdb_db *ret = NULL;
 110
 111         req = synchronous(ctdb,
 112                           ctdb_attachdb_send(ctdb, name, persistent, tdb_flags,
 113                                              set, &done),
 114                           &done);
 115         if (req != NULL) {
 116                 ret = ctdb_attachdb_recv(ctdb, req);
 117                 ctdb_request_free(req);
 118         }
 119         return ret;
 120 }
 121
 122 bool ctdb_getpnn(struct ctdb_connection *ctdb,
 123                  uint32_t destnode, uint32_t *pnn)
 124 {
 125         struct ctdb_request *req;
 126         bool done = false;
 127         bool ret = false;
 128
 129         req = synchronous(ctdb,
 130                           ctdb_getpnn_send(ctdb, destnode, set, &done),
 131                           &done);
 132         if (req != NULL) {
 133                 ret = ctdb_getpnn_recv(ctdb, req, pnn);
 134                 ctdb_request_free(req);
 135         }
 136         return ret;
 137 }
 138
 139 bool ctdb_getnodemap(struct ctdb_connection *ctdb,
 140                  uint32_t destnode, struct ctdb_node_map **nodemap)
 141 {
 142         struct ctdb_request *req;
 143         bool done = false;
 144         bool ret = false;
 145
 146         *nodemap = NULL;
 147
 148         req = synchronous(ctdb,
 149                           ctdb_getnodemap_send(ctdb, destnode, set, &done),
 150                           &done);
 151         if (req != NULL) {
 152                 ret = ctdb_getnodemap_recv(ctdb, req, nodemap);
 153                 ctdb_request_free(req);
 154         }
 155         return ret;
 156 }
 157
 158 bool ctdb_getpublicips(struct ctdb_connection *ctdb,
 159                        uint32_t destnode, struct ctdb_all_public_ips **ips)
 160 {
 161         struct ctdb_request *req;
 162         bool done = false;
 163         bool ret = false;
 164
 165         *ips = NULL;
 166
 167         req = synchronous(ctdb,
 168                           ctdb_getpublicips_send(ctdb, destnode, set, &done),
 169                           &done);
 170         if (req != NULL) {
 171                 ret = ctdb_getpublicips_recv(ctdb, req, ips);
 172                 ctdb_request_free(req);
 173         }
 174         return ret;
 175 }
 176
 177 bool ctdb_set_message_handler(struct ctdb_connection *ctdb, uint64_t srvid,
 178                               ctdb_message_fn_t handler, void *cbdata)
 179 {
 180         struct ctdb_request *req;
 181         bool done = false;
 182         bool ret = false;
 183
 184         req = synchronous(ctdb,
 185                           ctdb_set_message_handler_send(ctdb, srvid, handler,
 186                                                         cbdata, set, &done),
 187                           &done);
 188         if (req != NULL) {
 189                 ret = ctdb_set_message_handler_recv(ctdb, req);
 190                 ctdb_request_free(req);
 191         }
 192         return ret;
 193 }
 194
 195 struct rrl_info {
 196         bool done;
 197         struct ctdb_lock *lock;
 198         TDB_DATA *data;
 199 };
 200
 201 static void rrl_callback(struct ctdb_db *ctdb_db,
 202                          struct ctdb_lock *lock,
 203                          TDB_DATA data,
 204                          struct rrl_info *rrl)
 205 {
 206         rrl->done = true;
 207         rrl->lock = lock;
 208         *rrl->data = data;
 209 }
 210
 211 struct ctdb_lock *ctdb_readrecordlock(struct ctdb_connection *ctdb,
 212                                       struct ctdb_db *ctdb_db, TDB_DATA key,
 213                                       TDB_DATA *data)
 214 {
 215         struct pollfd fds;
 216         struct rrl_info rrl;
 217
 218         rrl.done = false;
 219         rrl.lock = NULL;
 220         rrl.data = data;
 221
 222         /* Immediate failure is easy. */
 223         if (!ctdb_readrecordlock_async(ctdb_db, key, rrl_callback, &rrl))
 224                 return NULL;
 225
 226         /* Immediate success is easy. */
 227         if (!rrl.done) {
 228                 /* Otherwise wait until callback called. */
 229                 fds.fd = ctdb_get_fd(ctdb);
 230                 while (!rrl.done) {
 231                         fds.events = ctdb_which_events(ctdb);
 232                         if (poll(&fds, 1, -1) < 0) {
 233                                 /* Signalled is OK, other error is bad. */
 234                                 if (errno == EINTR)
 235                                         continue;
 236                                 DEBUG(ctdb, LOG_ERR,
 237                                       "ctdb_readrecordlock: poll failed");
 238                                 return NULL;
 239                         }
 240                         if (!ctdb_service(ctdb, fds.revents)) {
 241                                 break;
 242                         }
 243                 }
 244         }
 245         return rrl.lock;
 246 }
 247
 248 bool ctdb_getdbseqnum(struct ctdb_connection *ctdb,
 249                       uint32_t destnode, uint32_t dbid,
 250                       uint64_t *seqnum)
 251 {
 252         struct ctdb_request *req;
 253         bool done = false;
 254         bool ret = false;
 255
 256         req = synchronous(ctdb,
 257                           ctdb_getdbseqnum_send(ctdb, destnode, dbid, set, &done),
 258                           &done);
 259         if (req != NULL) {
 260                 ret = ctdb_getdbseqnum_recv(ctdb, req, seqnum);
 261                 ctdb_request_free(req);
 262         }
 263         return ret;
 264 }