source3/lib/msg_channel.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    Samba3 message channels
   4    Copyright (C) Volker Lendecke 2012
   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 "includes.h"
  21 #include "msg_channel.h"
  22 #include "ctdb_conn.h"
  23 #include "lib/util/tevent_unix.h"
  24
  25 struct msg_channel {
  26         struct ctdb_msg_channel *ctdb_channel;
  27         struct messaging_context *msg;
  28         uint32_t msg_type;
  29
  30         struct tevent_req *pending_req;
  31         struct tevent_context *ev;
  32
  33         struct messaging_rec **msgs;
  34 };
  35
  36 struct msg_channel_init_state {
  37         struct msg_channel *channel;
  38 };
  39
  40 static void msg_channel_init_got_ctdb(struct tevent_req *subreq);
  41 static void msg_channel_init_got_msg(struct messaging_context *msg,
  42                                void *priv, uint32_t msg_type,
  43                                struct server_id server_id, DATA_BLOB *data);
  44 static int msg_channel_destructor(struct msg_channel *s);
  45
  46 struct tevent_req *msg_channel_init_send(TALLOC_CTX *mem_ctx,
  47                                     struct tevent_context *ev,
  48                                     struct messaging_context *msg,
  49                                     uint32_t msg_type)
  50 {
  51         struct tevent_req *req, *subreq;
  52         struct msg_channel_init_state *state;
  53         struct server_id pid;
  54
  55         req = tevent_req_create(mem_ctx, &state,
  56                                 struct msg_channel_init_state);
  57         if (req == NULL) {
  58                 return NULL;
  59         }
  60
  61         state->channel = talloc_zero(state, struct msg_channel);
  62         if (tevent_req_nomem(state->channel, req)) {
  63                 return tevent_req_post(req, ev);
  64         }
  65         state->channel->msg = msg;
  66         state->channel->msg_type = msg_type;
  67
  68         pid = messaging_server_id(msg);
  69         subreq = ctdb_msg_channel_init_send(state, ev, lp_ctdbd_socket(),
  70                                             pid.pid);
  71         if (tevent_req_nomem(subreq, req)) {
  72                 return tevent_req_post(req, ev);
  73         }
  74         tevent_req_set_callback(subreq, msg_channel_init_got_ctdb, req);
  75         return req;
  76 }
  77
  78 static void msg_channel_init_got_ctdb(struct tevent_req *subreq)
  79 {
  80         struct tevent_req *req = tevent_req_callback_data(
  81                 subreq, struct tevent_req);
  82         struct msg_channel_init_state *state = tevent_req_data(
  83                 req, struct msg_channel_init_state);
  84         struct msg_channel *s = state->channel;
  85         NTSTATUS status;
  86         int ret;
  87
  88         ret = ctdb_msg_channel_init_recv(subreq, s, &s->ctdb_channel);
  89         TALLOC_FREE(subreq);
  90
  91         if (ret == ENOSYS) {
  92                 s->ctdb_channel = NULL;
  93                 ret = 0;
  94         }
  95
  96         if (tevent_req_error(req, ret)) {
  97                 return;
  98         }
  99         status = messaging_register(s->msg, s, s->msg_type,
 100                                     msg_channel_init_got_msg);
 101         if (!NT_STATUS_IS_OK(status)) {
 102                 tevent_req_error(req, map_errno_from_nt_status(status));
 103                 return;
 104         }
 105         talloc_set_destructor(s, msg_channel_destructor);
 106         tevent_req_done(req);
 107 }
 108
 109 static int msg_channel_destructor(struct msg_channel *s)
 110 {
 111         messaging_deregister(s->msg, s->msg_type, s);
 112         return 0;
 113 }
 114
 115 int msg_channel_init_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 116                           struct msg_channel **pchannel)
 117 {
 118         struct msg_channel_init_state *state = tevent_req_data(
 119                 req, struct msg_channel_init_state);
 120         int err;
 121
 122         if (tevent_req_is_unix_error(req, &err)) {
 123                 return err;
 124         }
 125         *pchannel = talloc_move(mem_ctx, &state->channel);
 126         return 0;
 127 }
 128
 129 int msg_channel_init(TALLOC_CTX *mem_ctx, struct messaging_context *msg,
 130                      uint32_t msgtype, struct msg_channel **pchannel)
 131 {
 132         TALLOC_CTX *frame = talloc_stackframe();
 133         struct tevent_context *ev;
 134         struct tevent_req *req;
 135         int err = ENOMEM;
 136         bool ok;
 137
 138         ev = tevent_context_init(frame);
 139         if (ev == NULL) {
 140                 goto fail;
 141         }
 142         req = msg_channel_init_send(frame, ev, msg, msgtype);
 143         if (req == NULL) {
 144                 goto fail;
 145         }
 146         ok = tevent_req_poll(req, ev);
 147         if (!ok) {
 148                 err = errno;
 149                 goto fail;
 150         }
 151         err = msg_channel_init_recv(req, mem_ctx, pchannel);
 152 fail:
 153         TALLOC_FREE(frame);
 154         return err;
 155 }
 156
 157 struct msg_read_state {
 158         struct tevent_context *ev;
 159         struct msg_channel *channel;
 160         struct messaging_rec *rec;
 161 };
 162
 163 static void msg_channel_init_got_msg(struct messaging_context *msg,
 164                                      void *priv, uint32_t msg_type,
 165                                      struct server_id server_id,
 166                                      DATA_BLOB *data)
 167 {
 168         struct msg_channel *s = talloc_get_type_abort(
 169                 priv, struct msg_channel);
 170         struct messaging_rec *rec;
 171         struct messaging_rec **msgs;
 172         size_t num_msgs;
 173
 174         rec = talloc(s, struct messaging_rec);
 175         if (rec == NULL) {
 176                 goto fail;
 177         }
 178         rec->msg_version = 1;
 179         rec->msg_type = msg_type;
 180         rec->dest = server_id;
 181         rec->src = messaging_server_id(msg);
 182         rec->buf.data = (uint8_t *)talloc_memdup(rec, data->data,
 183                                                  data->length);
 184         if (rec->buf.data == NULL) {
 185                 goto fail;
 186         }
 187         rec->buf.length = data->length;
 188
 189         if (s->pending_req != NULL) {
 190                 struct tevent_req *req = s->pending_req;
 191                 struct msg_read_state *state = tevent_req_data(
 192                         req, struct msg_read_state);
 193
 194                 s->pending_req = NULL;
 195
 196                 state->rec = talloc_move(state, &rec);
 197                 tevent_req_defer_callback(req, s->ev);
 198                 tevent_req_done(req);
 199                 return;
 200         }
 201
 202         num_msgs = talloc_array_length(s->msgs);
 203         msgs = talloc_realloc(s, s->msgs, struct messaging_rec *, num_msgs+1);
 204         if (msgs == NULL) {
 205                 goto fail;
 206         }
 207         s->msgs = msgs;
 208         s->msgs[num_msgs] = talloc_move(s->msgs, &rec);
 209
 210         return;
 211 fail:
 212         TALLOC_FREE(rec);
 213 }
 214
 215 static void msg_read_got_ctdb(struct tevent_req *subreq);
 216
 217 struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
 218                                  struct tevent_context *ev,
 219                                  struct msg_channel *channel)
 220 {
 221         struct tevent_req *req;
 222         struct msg_read_state *state;
 223         void *msg_tdb_event;
 224         size_t num_msgs;
 225
 226         req = tevent_req_create(mem_ctx, &state, struct msg_read_state);
 227         if (req == NULL) {
 228                 return NULL;
 229         }
 230         state->ev = ev;
 231         state->channel = channel;
 232
 233         if (channel->pending_req != NULL) {
 234                 tevent_req_error(req, EBUSY);
 235                 return tevent_req_post(req, ev);
 236         }
 237
 238         num_msgs = talloc_array_length(channel->msgs);
 239         if (num_msgs != 0) {
 240                 state->rec = talloc_move(state, &channel->msgs[0]);
 241                 memmove(channel->msgs, channel->msgs+1,
 242                         sizeof(struct messaging_rec *) * (num_msgs-1));
 243                 channel->msgs = talloc_realloc(
 244                         channel, channel->msgs, struct messaging_rec *,
 245                         num_msgs - 1);
 246                 tevent_req_done(req);
 247                 return tevent_req_post(req, ev);
 248         }
 249
 250         channel->pending_req = req;
 251         channel->ev = ev;
 252
 253         msg_tdb_event = messaging_tdb_event(state, channel->msg, ev);
 254         if (tevent_req_nomem(msg_tdb_event, req)) {
 255                 return tevent_req_post(req, ev);
 256
 257         }
 258         if (channel->ctdb_channel != NULL) {
 259                 struct tevent_req *subreq;
 260
 261                 subreq = ctdb_msg_read_send(state, ev,
 262                                             channel->ctdb_channel);
 263                 if (tevent_req_nomem(subreq, req)) {
 264                         return tevent_req_post(req, ev);
 265                 }
 266                 tevent_req_set_callback(subreq, msg_read_got_ctdb, req);
 267         }
 268         return req;
 269 }
 270
 271 static void msg_read_got_ctdb(struct tevent_req *subreq)
 272 {
 273         struct tevent_req *req = tevent_req_callback_data(
 274                 subreq, struct tevent_req);
 275         struct msg_read_state *state = tevent_req_data(
 276                 req, struct msg_read_state);
 277         DATA_BLOB blob;
 278         enum ndr_err_code ndr_err;
 279         int ret;
 280
 281         ret = ctdb_msg_read_recv(subreq, talloc_tos(),
 282                                  &blob.data, &blob.length);
 283         TALLOC_FREE(subreq);
 284         if (tevent_req_error(req, ret)) {
 285                 return;
 286         }
 287
 288         state->rec = talloc(state, struct messaging_rec);
 289         if (tevent_req_nomem(state->rec, req)) {
 290                 return;
 291         }
 292
 293         ndr_err = ndr_pull_struct_blob(
 294                 &blob, state->rec, state->rec,
 295                 (ndr_pull_flags_fn_t)ndr_pull_messaging_rec);
 296
 297         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 298                 DEBUG(1, ("ndr_pull_struct_blob failed: %s\n",
 299                           ndr_errstr(ndr_err)));
 300                 tevent_req_error(req, ndr_map_error2errno(ndr_err));
 301                 return;
 302         }
 303         if (DEBUGLEVEL >= 10) {
 304                 NDR_PRINT_DEBUG(messaging_rec, state->rec);
 305         }
 306         if (state->rec->msg_type == state->channel->msg_type) {
 307                 tevent_req_done(req);
 308                 return;
 309         }
 310         /*
 311          * Got some unexpected msg type, wait for the next one
 312          */
 313         subreq = ctdb_msg_read_send(state, state->ev,
 314                                     state->channel->ctdb_channel);
 315         if (tevent_req_nomem(subreq, req)) {
 316                 return;
 317         }
 318         tevent_req_set_callback(subreq, msg_read_got_ctdb, req);
 319 }
 320
 321 int msg_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 322                   struct messaging_rec **prec)
 323 {
 324         struct msg_read_state *state = tevent_req_data(
 325                 req, struct msg_read_state);
 326         int err;
 327
 328         if (tevent_req_is_unix_error(req, &err)) {
 329                 return err;
 330         }
 331         *prec = talloc_move(mem_ctx, &state->rec);
 332         tevent_req_received(req);
 333         return 0;
 334 }