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 void msg_channel_trigger(struct tevent_context *ev,
  45                                 struct tevent_immediate *im,
  46                                 void *priv);
  47 static int msg_channel_init_destructor(struct msg_channel *s);
  48
  49 struct tevent_req *msg_channel_init_send(TALLOC_CTX *mem_ctx,
  50                                     struct tevent_context *ev,
  51                                     struct messaging_context *msg,
  52                                     uint32_t msg_type)
  53 {
  54         struct tevent_req *req, *subreq;
  55         struct msg_channel_init_state *state;
  56         struct server_id pid;
  57
  58         req = tevent_req_create(mem_ctx, &state,
  59                                 struct msg_channel_init_state);
  60         if (req == NULL) {
  61                 return NULL;
  62         }
  63
  64         state->channel = talloc_zero(state, struct msg_channel);
  65         if (tevent_req_nomem(state->channel, req)) {
  66                 return tevent_req_post(req, ev);
  67         }
  68         state->channel->msg = msg;
  69         state->channel->msg_type = msg_type;
  70
  71         pid = messaging_server_id(msg);
  72         subreq = ctdb_msg_channel_init_send(state, ev, lp_ctdbd_socket(),
  73                                             pid.pid);
  74         if (tevent_req_nomem(subreq, req)) {
  75                 return tevent_req_post(req, ev);
  76         }
  77         tevent_req_set_callback(subreq, msg_channel_init_got_ctdb, req);
  78         return req;
  79 }
  80
  81 static void msg_channel_init_got_ctdb(struct tevent_req *subreq)
  82 {
  83         struct tevent_req *req = tevent_req_callback_data(
  84                 subreq, struct tevent_req);
  85         struct msg_channel_init_state *state = tevent_req_data(
  86                 req, struct msg_channel_init_state);
  87         struct msg_channel *s = state->channel;
  88         NTSTATUS status;
  89         int ret;
  90
  91         ret = ctdb_msg_channel_init_recv(subreq, s, &s->ctdb_channel);
  92         TALLOC_FREE(subreq);
  93
  94         if (ret == ENOSYS) {
  95                 s->ctdb_channel = NULL;
  96                 ret = 0;
  97         }
  98
  99         if (tevent_req_error(req, ret)) {
 100                 return;
 101         }
 102         status = messaging_register(s->msg, s, s->msg_type,
 103                                     msg_channel_init_got_msg);
 104         if (!NT_STATUS_IS_OK(status)) {
 105                 tevent_req_error(req, map_errno_from_nt_status(status));
 106                 return;
 107         }
 108         talloc_set_destructor(s, msg_channel_init_destructor);
 109         tevent_req_done(req);
 110 }
 111
 112 static int msg_channel_init_destructor(struct msg_channel *s)
 113 {
 114         messaging_deregister(s->msg, s->msg_type, s);
 115         return 0;
 116 }
 117
 118 int msg_channel_init_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 119                           struct msg_channel **pchannel)
 120 {
 121         struct msg_channel_init_state *state = tevent_req_data(
 122                 req, struct msg_channel_init_state);
 123         int err;
 124
 125         if (tevent_req_is_unix_error(req, &err)) {
 126                 return err;
 127         }
 128         *pchannel = talloc_move(mem_ctx, &state->channel);
 129         return 0;
 130 }
 131
 132 int msg_channel_init(TALLOC_CTX *mem_ctx, struct messaging_context *msg,
 133                      uint32_t msgtype, struct msg_channel **pchannel)
 134 {
 135         TALLOC_CTX *frame = talloc_stackframe();
 136         struct tevent_context *ev;
 137         struct tevent_req *req;
 138         int err = ENOMEM;
 139         bool ok;
 140
 141         ev = tevent_context_init(frame);
 142         if (ev == NULL) {
 143                 goto fail;
 144         }
 145         req = msg_channel_init_send(frame, ev, msg, msgtype);
 146         if (req == NULL) {
 147                 goto fail;
 148         }
 149         ok = tevent_req_poll(req, ev);
 150         if (!ok) {
 151                 err = errno;
 152                 goto fail;
 153         }
 154         err = msg_channel_init_recv(req, mem_ctx, pchannel);
 155 fail:
 156         TALLOC_FREE(frame);
 157         return err;
 158 }
 159
 160 static void msg_channel_init_got_msg(struct messaging_context *msg,
 161                                      void *priv, uint32_t msg_type,
 162                                      struct server_id server_id,
 163                                      DATA_BLOB *data)
 164 {
 165         struct msg_channel *s = talloc_get_type_abort(
 166                 priv, struct msg_channel);
 167         struct messaging_rec *rec;
 168         struct messaging_rec **msgs;
 169         size_t num_msgs;
 170         struct tevent_immediate *im;
 171
 172         rec = talloc(s, struct messaging_rec);
 173         if (rec == NULL) {
 174                 goto fail;
 175         }
 176         rec->msg_version = 1;
 177         rec->msg_type = msg_type;
 178         rec->dest = server_id;
 179         rec->src = messaging_server_id(msg);
 180         rec->buf.data = (uint8_t *)talloc_memdup(rec, data->data,
 181                                                  data->length);
 182         if (rec->buf.data == NULL) {
 183                 goto fail;
 184         }
 185         rec->buf.length = data->length;
 186
 187         num_msgs = talloc_array_length(s->msgs);
 188         msgs = talloc_realloc(s, s->msgs, struct messaging_rec *, num_msgs+1);
 189         if (msgs == NULL) {
 190                 goto fail;
 191         }
 192         s->msgs = msgs;
 193         s->msgs[num_msgs] = talloc_move(s->msgs, &rec);
 194
 195         if (s->pending_req == NULL) {
 196                 return;
 197         }
 198
 199         im = tevent_create_immediate(s->ev);
 200         if (im == NULL) {
 201                 goto fail;
 202         }
 203         tevent_schedule_immediate(im, s->ev, msg_channel_trigger, s);
 204         return;
 205 fail:
 206         TALLOC_FREE(rec);
 207 }
 208
 209 struct msg_read_state {
 210         struct tevent_context *ev;
 211         struct tevent_req *req;
 212         struct msg_channel *channel;
 213         struct messaging_rec *rec;
 214 };
 215
 216 static int msg_read_state_destructor(struct msg_read_state *s);
 217 static void msg_read_got_ctdb(struct tevent_req *subreq);
 218
 219 struct tevent_req *msg_read_send(TALLOC_CTX *mem_ctx,
 220                                  struct tevent_context *ev,
 221                                  struct msg_channel *channel)
 222 {
 223         struct tevent_req *req;
 224         struct tevent_immediate *im;
 225         struct msg_read_state *state;
 226         void *msg_tdb_event;
 227         size_t num_msgs;
 228
 229         req = tevent_req_create(mem_ctx, &state, struct msg_read_state);
 230         if (req == NULL) {
 231                 return NULL;
 232         }
 233         state->ev = ev;
 234         state->req = req;
 235         state->channel = channel;
 236
 237         if (channel->pending_req != NULL) {
 238                 tevent_req_error(req, EBUSY);
 239                 return tevent_req_post(req, ev);
 240         }
 241         channel->pending_req = req;
 242         channel->ev = ev;
 243         talloc_set_destructor(state, msg_read_state_destructor);
 244
 245         num_msgs = talloc_array_length(channel->msgs);
 246         if (num_msgs != 0) {
 247                 im = tevent_create_immediate(channel->ev);
 248                 if (tevent_req_nomem(im, req)) {
 249                         return tevent_req_post(req, ev);
 250                 }
 251                 tevent_schedule_immediate(im, channel->ev, msg_channel_trigger,
 252                                           channel);
 253                 return req;
 254         }
 255
 256         msg_tdb_event = messaging_tdb_event(state, channel->msg, ev);
 257         if (tevent_req_nomem(msg_tdb_event, req)) {
 258                 return tevent_req_post(req, ev);
 259
 260         }
 261         if (channel->ctdb_channel != NULL) {
 262                 struct tevent_req *subreq;
 263
 264                 subreq = ctdb_msg_read_send(state, ev,
 265                                             channel->ctdb_channel);
 266                 if (tevent_req_nomem(subreq, req)) {
 267                         return tevent_req_post(req, ev);
 268                 }
 269                 tevent_req_set_callback(subreq, msg_read_got_ctdb, req);
 270         }
 271         return req;
 272 }
 273
 274 static int msg_read_state_destructor(struct msg_read_state *s)
 275 {
 276         assert(s->channel->pending_req == s->req);
 277         s->channel->pending_req = NULL;
 278         return 0;
 279 }
 280
 281 static void msg_channel_trigger(struct tevent_context *ev,
 282                                struct tevent_immediate *im,
 283                                void *priv)
 284 {
 285         struct msg_channel *channel;
 286         struct tevent_req *req;
 287         struct msg_read_state *state;
 288         size_t num_msgs;
 289
 290         channel = talloc_get_type_abort(priv, struct msg_channel);
 291         req = channel->pending_req;
 292         state = tevent_req_data(req, struct msg_read_state);
 293
 294         talloc_set_destructor(state, NULL);
 295         msg_read_state_destructor(state);
 296
 297         num_msgs = talloc_array_length(channel->msgs);
 298         assert(num_msgs > 0);
 299
 300         state->rec = talloc_move(state, &channel->msgs[0]);
 301
 302         memmove(channel->msgs, channel->msgs+1,
 303                 sizeof(struct messaging_rec) * (num_msgs-1));
 304         channel->msgs = talloc_realloc(
 305                 channel, channel->msgs, struct messaging_rec *, num_msgs - 1);
 306
 307         tevent_req_done(req);
 308 }
 309
 310 static void msg_read_got_ctdb(struct tevent_req *subreq)
 311 {
 312         struct tevent_req *req = tevent_req_callback_data(
 313                 subreq, struct tevent_req);
 314         struct msg_read_state *state = tevent_req_data(
 315                 req, struct msg_read_state);
 316         DATA_BLOB blob;
 317         enum ndr_err_code ndr_err;
 318         int ret;
 319
 320         ret = ctdb_msg_read_recv(subreq, talloc_tos(),
 321                                  &blob.data, &blob.length);
 322         TALLOC_FREE(subreq);
 323         if (tevent_req_error(req, ret)) {
 324                 return;
 325         }
 326
 327         state->rec = talloc(state, struct messaging_rec);
 328         if (tevent_req_nomem(state->rec, req)) {
 329                 return;
 330         }
 331
 332         ndr_err = ndr_push_struct_blob(
 333                 &blob, state->rec, state->rec,
 334                 (ndr_push_flags_fn_t)ndr_push_messaging_rec);
 335
 336         if (!NDR_ERR_CODE_IS_SUCCESS(ndr_err)) {
 337                 DEBUG(0, ("ndr_push_struct_blob failed: %s\n",
 338                           ndr_errstr(ndr_err)));
 339                 tevent_req_error(req, ndr_map_error2errno(ndr_err));
 340                 return;
 341         }
 342         if (state->rec->msg_type == state->channel->msg_type) {
 343                 tevent_req_done(req);
 344                 return;
 345         }
 346         /*
 347          * Got some unexpected msg type, wait for the next one
 348          */
 349         subreq = ctdb_msg_read_send(state, state->ev,
 350                                     state->channel->ctdb_channel);
 351         if (tevent_req_nomem(subreq, req)) {
 352                 return;
 353         }
 354         tevent_req_set_callback(subreq, msg_read_got_ctdb, req);
 355 }
 356
 357 int msg_read_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 358                   struct messaging_rec **prec)
 359 {
 360         struct msg_read_state *state = tevent_req_data(
 361                 req, struct msg_read_state);
 362         int err;
 363
 364         if (tevent_req_is_unix_error(req, &err)) {
 365                 return err;
 366         }
 367         *prec = talloc_move(mem_ctx, &state->rec);
 368         return 0;
 369 }