lib/async_req/async_sock.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    async socket syscalls
   4    Copyright (C) Volker Lendecke 2008
   5
   6      ** NOTE! The following LGPL license applies to the async_sock
   7      ** library. This does NOT imply that all of Samba is released
   8      ** under the LGPL
   9
  10    This library is free software; you can redistribute it and/or
  11    modify it under the terms of the GNU Lesser General Public
  12    License as published by the Free Software Foundation; either
  13    version 3 of the License, or (at your option) any later version.
  14
  15    This library is distributed in the hope that it will be useful,
  16    but WITHOUT ANY WARRANTY; without even the implied warranty of
  17    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  18    Library General Public License for more details.
  19
  20    You should have received a copy of the GNU Lesser General Public License
  21    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  22 */
  23
  24 #include "replace.h"
  25 #include "system/network.h"
  26 #include "system/filesys.h"
  27 #include <talloc.h>
  28 #include <tevent.h>
  29 #include "lib/async_req/async_sock.h"
  30
  31 /* Note: lib/util/ is currently GPL */
  32 #include "lib/util/tevent_unix.h"
  33 #include "lib/util/samba_util.h"
  34
  35 #ifndef TALLOC_FREE
  36 #define TALLOC_FREE(ctx) do { talloc_free(ctx); ctx=NULL; } while(0)
  37 #endif
  38
  39 struct sendto_state {
  40         int fd;
  41         const void *buf;
  42         size_t len;
  43         int flags;
  44         const struct sockaddr_storage *addr;
  45         socklen_t addr_len;
  46         ssize_t sent;
  47 };
  48
  49 static void sendto_handler(struct tevent_context *ev,
  50                                struct tevent_fd *fde,
  51                                uint16_t flags, void *private_data);
  52
  53 struct tevent_req *sendto_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
  54                                int fd, const void *buf, size_t len, int flags,
  55                                const struct sockaddr_storage *addr)
  56 {
  57         struct tevent_req *result;
  58         struct sendto_state *state;
  59         struct tevent_fd *fde;
  60
  61         result = tevent_req_create(mem_ctx, &state, struct sendto_state);
  62         if (result == NULL) {
  63                 return result;
  64         }
  65         state->fd = fd;
  66         state->buf = buf;
  67         state->len = len;
  68         state->flags = flags;
  69         state->addr = addr;
  70
  71         switch (addr->ss_family) {
  72         case AF_INET:
  73                 state->addr_len = sizeof(struct sockaddr_in);
  74                 break;
  75 #if defined(HAVE_IPV6)
  76         case AF_INET6:
  77                 state->addr_len = sizeof(struct sockaddr_in6);
  78                 break;
  79 #endif
  80         case AF_UNIX:
  81                 state->addr_len = sizeof(struct sockaddr_un);
  82                 break;
  83         default:
  84                 state->addr_len = sizeof(struct sockaddr_storage);
  85                 break;
  86         }
  87
  88         fde = tevent_add_fd(ev, state, fd, TEVENT_FD_WRITE, sendto_handler,
  89                             result);
  90         if (fde == NULL) {
  91                 TALLOC_FREE(result);
  92                 return NULL;
  93         }
  94         return result;
  95 }
  96
  97 static void sendto_handler(struct tevent_context *ev,
  98                                struct tevent_fd *fde,
  99                                uint16_t flags, void *private_data)
 100 {
 101         struct tevent_req *req = talloc_get_type_abort(
 102                 private_data, struct tevent_req);
 103         struct sendto_state *state =
 104                 tevent_req_data(req, struct sendto_state);
 105
 106         state->sent = sendto(state->fd, state->buf, state->len, state->flags,
 107                              (const struct sockaddr *)state->addr,
 108                              state->addr_len);
 109         if ((state->sent == -1) && (errno == EINTR)) {
 110                 /* retry */
 111                 return;
 112         }
 113         if (state->sent == -1) {
 114                 tevent_req_error(req, errno);
 115                 return;
 116         }
 117         tevent_req_done(req);
 118 }
 119
 120 ssize_t sendto_recv(struct tevent_req *req, int *perrno)
 121 {
 122         struct sendto_state *state =
 123                 tevent_req_data(req, struct sendto_state);
 124
 125         if (tevent_req_is_unix_error(req, perrno)) {
 126                 return -1;
 127         }
 128         return state->sent;
 129 }
 130
 131 struct recvfrom_state {
 132         int fd;
 133         void *buf;
 134         size_t len;
 135         int flags;
 136         struct sockaddr_storage *addr;
 137         socklen_t *addr_len;
 138         ssize_t received;
 139 };
 140
 141 static void recvfrom_handler(struct tevent_context *ev,
 142                                struct tevent_fd *fde,
 143                                uint16_t flags, void *private_data);
 144
 145 struct tevent_req *recvfrom_send(TALLOC_CTX *mem_ctx,
 146                                  struct tevent_context *ev,
 147                                  int fd, void *buf, size_t len, int flags,
 148                                  struct sockaddr_storage *addr,
 149                                  socklen_t *addr_len)
 150 {
 151         struct tevent_req *result;
 152         struct recvfrom_state *state;
 153         struct tevent_fd *fde;
 154
 155         result = tevent_req_create(mem_ctx, &state, struct recvfrom_state);
 156         if (result == NULL) {
 157                 return result;
 158         }
 159         state->fd = fd;
 160         state->buf = buf;
 161         state->len = len;
 162         state->flags = flags;
 163         state->addr = addr;
 164         state->addr_len = addr_len;
 165
 166         fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ, recvfrom_handler,
 167                             result);
 168         if (fde == NULL) {
 169                 TALLOC_FREE(result);
 170                 return NULL;
 171         }
 172         return result;
 173 }
 174
 175 static void recvfrom_handler(struct tevent_context *ev,
 176                                struct tevent_fd *fde,
 177                                uint16_t flags, void *private_data)
 178 {
 179         struct tevent_req *req = talloc_get_type_abort(
 180                 private_data, struct tevent_req);
 181         struct recvfrom_state *state =
 182                 tevent_req_data(req, struct recvfrom_state);
 183
 184         state->received = recvfrom(state->fd, state->buf, state->len,
 185                                    state->flags, (struct sockaddr *)state->addr,
 186                                    state->addr_len);
 187         if ((state->received == -1) && (errno == EINTR)) {
 188                 /* retry */
 189                 return;
 190         }
 191         if (state->received == 0) {
 192                 tevent_req_error(req, EPIPE);
 193                 return;
 194         }
 195         if (state->received == -1) {
 196                 tevent_req_error(req, errno);
 197                 return;
 198         }
 199         tevent_req_done(req);
 200 }
 201
 202 ssize_t recvfrom_recv(struct tevent_req *req, int *perrno)
 203 {
 204         struct recvfrom_state *state =
 205                 tevent_req_data(req, struct recvfrom_state);
 206
 207         if (tevent_req_is_unix_error(req, perrno)) {
 208                 return -1;
 209         }
 210         return state->received;
 211 }
 212
 213 struct async_connect_state {
 214         int fd;
 215         int result;
 216         int sys_errno;
 217         long old_sockflags;
 218         socklen_t address_len;
 219         struct sockaddr_storage address;
 220 };
 221
 222 static void async_connect_connected(struct tevent_context *ev,
 223                                     struct tevent_fd *fde, uint16_t flags,
 224                                     void *priv);
 225
 226 /**
 227  * @brief async version of connect(2)
 228  * @param[in] mem_ctx   The memory context to hang the result off
 229  * @param[in] ev        The event context to work from
 230  * @param[in] fd        The socket to recv from
 231  * @param[in] address   Where to connect?
 232  * @param[in] address_len Length of *address
 233  * @retval The async request
 234  *
 235  * This function sets the socket into non-blocking state to be able to call
 236  * connect in an async state. This will be reset when the request is finished.
 237  */
 238
 239 struct tevent_req *async_connect_send(TALLOC_CTX *mem_ctx,
 240                                       struct tevent_context *ev,
 241                                       int fd, const struct sockaddr *address,
 242                                       socklen_t address_len)
 243 {
 244         struct tevent_req *result;
 245         struct async_connect_state *state;
 246         struct tevent_fd *fde;
 247
 248         result = tevent_req_create(
 249                 mem_ctx, &state, struct async_connect_state);
 250         if (result == NULL) {
 251                 return NULL;
 252         }
 253
 254         /**
 255          * We have to set the socket to nonblocking for async connect(2). Keep
 256          * the old sockflags around.
 257          */
 258
 259         state->fd = fd;
 260         state->sys_errno = 0;
 261
 262         state->old_sockflags = fcntl(fd, F_GETFL, 0);
 263         if (state->old_sockflags == -1) {
 264                 goto post_errno;
 265         }
 266
 267         state->address_len = address_len;
 268         if (address_len > sizeof(state->address)) {
 269                 errno = EINVAL;
 270                 goto post_errno;
 271         }
 272         memcpy(&state->address, address, address_len);
 273
 274         set_blocking(fd, false);
 275
 276         state->result = connect(fd, address, address_len);
 277         if (state->result == 0) {
 278                 tevent_req_done(result);
 279                 goto done;
 280         }
 281
 282         /**
 283          * A number of error messages show that something good is progressing
 284          * and that we have to wait for readability.
 285          *
 286          * If none of them are present, bail out.
 287          */
 288
 289         if (!(errno == EINPROGRESS || errno == EALREADY ||
 290 #ifdef EISCONN
 291               errno == EISCONN ||
 292 #endif
 293               errno == EAGAIN || errno == EINTR)) {
 294                 state->sys_errno = errno;
 295                 goto post_errno;
 296         }
 297
 298         fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ | TEVENT_FD_WRITE,
 299                            async_connect_connected, result);
 300         if (fde == NULL) {
 301                 state->sys_errno = ENOMEM;
 302                 goto post_errno;
 303         }
 304         return result;
 305
 306  post_errno:
 307         tevent_req_error(result, state->sys_errno);
 308  done:
 309         fcntl(fd, F_SETFL, state->old_sockflags);
 310         return tevent_req_post(result, ev);
 311 }
 312
 313 /**
 314  * fde event handler for connect(2)
 315  * @param[in] ev        The event context that sent us here
 316  * @param[in] fde       The file descriptor event associated with the connect
 317  * @param[in] flags     Indicate read/writeability of the socket
 318  * @param[in] priv      private data, "struct async_req *" in this case
 319  */
 320
 321 static void async_connect_connected(struct tevent_context *ev,
 322                                     struct tevent_fd *fde, uint16_t flags,
 323                                     void *priv)
 324 {
 325         struct tevent_req *req = talloc_get_type_abort(
 326                 priv, struct tevent_req);
 327         struct async_connect_state *state =
 328                 tevent_req_data(req, struct async_connect_state);
 329         int ret;
 330
 331         ret = connect(state->fd, (struct sockaddr *)(void *)&state->address,
 332                       state->address_len);
 333         if (ret == 0) {
 334                 state->sys_errno = 0;
 335                 TALLOC_FREE(fde);
 336                 tevent_req_done(req);
 337                 return;
 338         }
 339         if (errno == EINPROGRESS) {
 340                 /* Try again later, leave the fde around */
 341                 return;
 342         }
 343         state->sys_errno = errno;
 344         TALLOC_FREE(fde);
 345         tevent_req_error(req, errno);
 346         return;
 347 }
 348
 349 int async_connect_recv(struct tevent_req *req, int *perrno)
 350 {
 351         struct async_connect_state *state =
 352                 tevent_req_data(req, struct async_connect_state);
 353         int err;
 354
 355         fcntl(state->fd, F_SETFL, state->old_sockflags);
 356
 357         if (tevent_req_is_unix_error(req, &err)) {
 358                 *perrno = err;
 359                 return -1;
 360         }
 361
 362         if (state->sys_errno == 0) {
 363                 return 0;
 364         }
 365
 366         *perrno = state->sys_errno;
 367         return -1;
 368 }
 369
 370 struct writev_state {
 371         struct tevent_context *ev;
 372         int fd;
 373         struct iovec *iov;
 374         int count;
 375         size_t total_size;
 376         uint16_t flags;
 377         bool err_on_readability;
 378 };
 379
 380 static void writev_trigger(struct tevent_req *req, void *private_data);
 381 static void writev_handler(struct tevent_context *ev, struct tevent_fd *fde,
 382                            uint16_t flags, void *private_data);
 383
 384 struct tevent_req *writev_send(TALLOC_CTX *mem_ctx, struct tevent_context *ev,
 385                                struct tevent_queue *queue, int fd,
 386                                bool err_on_readability,
 387                                struct iovec *iov, int count)
 388 {
 389         struct tevent_req *req;
 390         struct writev_state *state;
 391
 392         req = tevent_req_create(mem_ctx, &state, struct writev_state);
 393         if (req == NULL) {
 394                 return NULL;
 395         }
 396         state->ev = ev;
 397         state->fd = fd;
 398         state->total_size = 0;
 399         state->count = count;
 400         state->iov = (struct iovec *)talloc_memdup(
 401                 state, iov, sizeof(struct iovec) * count);
 402         if (state->iov == NULL) {
 403                 goto fail;
 404         }
 405         state->flags = TEVENT_FD_WRITE|TEVENT_FD_READ;
 406         state->err_on_readability = err_on_readability;
 407
 408         if (queue == NULL) {
 409                 struct tevent_fd *fde;
 410                 fde = tevent_add_fd(state->ev, state, state->fd,
 411                                     state->flags, writev_handler, req);
 412                 if (tevent_req_nomem(fde, req)) {
 413                         return tevent_req_post(req, ev);
 414                 }
 415                 return req;
 416         }
 417
 418         if (!tevent_queue_add(queue, ev, req, writev_trigger, NULL)) {
 419                 goto fail;
 420         }
 421         return req;
 422  fail:
 423         TALLOC_FREE(req);
 424         return NULL;
 425 }
 426
 427 static void writev_trigger(struct tevent_req *req, void *private_data)
 428 {
 429         struct writev_state *state = tevent_req_data(req, struct writev_state);
 430         struct tevent_fd *fde;
 431
 432         fde = tevent_add_fd(state->ev, state, state->fd, state->flags,
 433                             writev_handler, req);
 434         if (fde == NULL) {
 435                 tevent_req_error(req, ENOMEM);
 436         }
 437 }
 438
 439 static void writev_handler(struct tevent_context *ev, struct tevent_fd *fde,
 440                            uint16_t flags, void *private_data)
 441 {
 442         struct tevent_req *req = talloc_get_type_abort(
 443                 private_data, struct tevent_req);
 444         struct writev_state *state =
 445                 tevent_req_data(req, struct writev_state);
 446         size_t to_write, written;
 447         int i;
 448
 449         to_write = 0;
 450
 451         if ((state->flags & TEVENT_FD_READ) && (flags & TEVENT_FD_READ)) {
 452                 int ret, value;
 453
 454                 if (state->err_on_readability) {
 455                         /* Readable and the caller wants an error on read. */
 456                         tevent_req_error(req, EPIPE);
 457                         return;
 458                 }
 459
 460                 /* Might be an error. Check if there are bytes to read */
 461                 ret = ioctl(state->fd, FIONREAD, &value);
 462                 /* FIXME - should we also check
 463                    for ret == 0 and value == 0 here ? */
 464                 if (ret == -1) {
 465                         /* There's an error. */
 466                         tevent_req_error(req, EPIPE);
 467                         return;
 468                 }
 469                 /* A request for TEVENT_FD_READ will succeed from now and
 470                    forevermore until the bytes are read so if there was
 471                    an error we'll wait until we do read, then get it in
 472                    the read callback function. Until then, remove TEVENT_FD_READ
 473                    from the flags we're waiting for. */
 474                 state->flags &= ~TEVENT_FD_READ;
 475                 TEVENT_FD_NOT_READABLE(fde);
 476
 477                 /* If not writable, we're done. */
 478                 if (!(flags & TEVENT_FD_WRITE)) {
 479                         return;
 480                 }
 481         }
 482
 483         for (i=0; i<state->count; i++) {
 484                 to_write += state->iov[i].iov_len;
 485         }
 486
 487         written = writev(state->fd, state->iov, state->count);
 488         if ((written == -1) && (errno == EINTR)) {
 489                 /* retry */
 490                 return;
 491         }
 492         if (written == -1) {
 493                 tevent_req_error(req, errno);
 494                 return;
 495         }
 496         if (written == 0) {
 497                 tevent_req_error(req, EPIPE);
 498                 return;
 499         }
 500         state->total_size += written;
 501
 502         if (written == to_write) {
 503                 tevent_req_done(req);
 504                 return;
 505         }
 506
 507         /*
 508          * We've written less than we were asked to, drop stuff from
 509          * state->iov.
 510          */
 511
 512         while (written > 0) {
 513                 if (written < state->iov[0].iov_len) {
 514                         state->iov[0].iov_base =
 515                                 (char *)state->iov[0].iov_base + written;
 516                         state->iov[0].iov_len -= written;
 517                         break;
 518                 }
 519                 written -= state->iov[0].iov_len;
 520                 state->iov += 1;
 521                 state->count -= 1;
 522         }
 523 }
 524
 525 ssize_t writev_recv(struct tevent_req *req, int *perrno)
 526 {
 527         struct writev_state *state =
 528                 tevent_req_data(req, struct writev_state);
 529
 530         if (tevent_req_is_unix_error(req, perrno)) {
 531                 return -1;
 532         }
 533         return state->total_size;
 534 }
 535
 536 struct read_packet_state {
 537         int fd;
 538         uint8_t *buf;
 539         size_t nread;
 540         ssize_t (*more)(uint8_t *buf, size_t buflen, void *private_data);
 541         void *private_data;
 542 };
 543
 544 static void read_packet_handler(struct tevent_context *ev,
 545                                 struct tevent_fd *fde,
 546                                 uint16_t flags, void *private_data);
 547
 548 struct tevent_req *read_packet_send(TALLOC_CTX *mem_ctx,
 549                                     struct tevent_context *ev,
 550                                     int fd, size_t initial,
 551                                     ssize_t (*more)(uint8_t *buf,
 552                                                     size_t buflen,
 553                                                     void *private_data),
 554                                     void *private_data)
 555 {
 556         struct tevent_req *result;
 557         struct read_packet_state *state;
 558         struct tevent_fd *fde;
 559
 560         result = tevent_req_create(mem_ctx, &state, struct read_packet_state);
 561         if (result == NULL) {
 562                 return NULL;
 563         }
 564         state->fd = fd;
 565         state->nread = 0;
 566         state->more = more;
 567         state->private_data = private_data;
 568
 569         state->buf = talloc_array(state, uint8_t, initial);
 570         if (state->buf == NULL) {
 571                 goto fail;
 572         }
 573
 574         fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ, read_packet_handler,
 575                             result);
 576         if (fde == NULL) {
 577                 goto fail;
 578         }
 579         return result;
 580  fail:
 581         TALLOC_FREE(result);
 582         return NULL;
 583 }
 584
 585 static void read_packet_handler(struct tevent_context *ev,
 586                                 struct tevent_fd *fde,
 587                                 uint16_t flags, void *private_data)
 588 {
 589         struct tevent_req *req = talloc_get_type_abort(
 590                 private_data, struct tevent_req);
 591         struct read_packet_state *state =
 592                 tevent_req_data(req, struct read_packet_state);
 593         size_t total = talloc_get_size(state->buf);
 594         ssize_t nread, more;
 595         uint8_t *tmp;
 596
 597         nread = recv(state->fd, state->buf+state->nread, total-state->nread,
 598                      0);
 599         if ((nread == -1) && (errno == ENOTSOCK)) {
 600                 nread = read(state->fd, state->buf+state->nread,
 601                              total-state->nread);
 602         }
 603         if ((nread == -1) && (errno == EINTR)) {
 604                 /* retry */
 605                 return;
 606         }
 607         if (nread == -1) {
 608                 tevent_req_error(req, errno);
 609                 return;
 610         }
 611         if (nread == 0) {
 612                 tevent_req_error(req, EPIPE);
 613                 return;
 614         }
 615
 616         state->nread += nread;
 617         if (state->nread < total) {
 618                 /* Come back later */
 619                 return;
 620         }
 621
 622         /*
 623          * We got what was initially requested. See if "more" asks for -- more.
 624          */
 625         if (state->more == NULL) {
 626                 /* Nobody to ask, this is a async read_data */
 627                 tevent_req_done(req);
 628                 return;
 629         }
 630
 631         more = state->more(state->buf, total, state->private_data);
 632         if (more == -1) {
 633                 /* We got an invalid packet, tell the caller */
 634                 tevent_req_error(req, EIO);
 635                 return;
 636         }
 637         if (more == 0) {
 638                 /* We're done, full packet received */
 639                 tevent_req_done(req);
 640                 return;
 641         }
 642
 643         if (total + more < total) {
 644                 tevent_req_error(req, EMSGSIZE);
 645                 return;
 646         }
 647
 648         tmp = talloc_realloc(state, state->buf, uint8_t, total+more);
 649         if (tevent_req_nomem(tmp, req)) {
 650                 return;
 651         }
 652         state->buf = tmp;
 653 }
 654
 655 ssize_t read_packet_recv(struct tevent_req *req, TALLOC_CTX *mem_ctx,
 656                          uint8_t **pbuf, int *perrno)
 657 {
 658         struct read_packet_state *state =
 659                 tevent_req_data(req, struct read_packet_state);
 660
 661         if (tevent_req_is_unix_error(req, perrno)) {
 662                 return -1;
 663         }
 664         *pbuf = talloc_move(mem_ctx, &state->buf);
 665         return talloc_get_size(*pbuf);
 666 }
 667
 668 struct wait_for_read_state {
 669         struct tevent_req *req;
 670         struct tevent_fd *fde;
 671 };
 672
 673 static void wait_for_read_done(struct tevent_context *ev,
 674                                struct tevent_fd *fde,
 675                                uint16_t flags,
 676                                void *private_data);
 677
 678 struct tevent_req *wait_for_read_send(TALLOC_CTX *mem_ctx,
 679                                       struct tevent_context *ev,
 680                                       int fd)
 681 {
 682         struct tevent_req *req;
 683         struct wait_for_read_state *state;
 684
 685         req = tevent_req_create(mem_ctx, &state, struct wait_for_read_state);
 686         if (req == NULL) {
 687                 return NULL;
 688         }
 689         state->req = req;
 690         state->fde = tevent_add_fd(ev, state, fd, TEVENT_FD_READ,
 691                                    wait_for_read_done, state);
 692         if (tevent_req_nomem(state->fde, req)) {
 693                 return tevent_req_post(req, ev);
 694         }
 695         return req;
 696 }
 697
 698 static void wait_for_read_done(struct tevent_context *ev,
 699                                struct tevent_fd *fde,
 700                                uint16_t flags,
 701                                void *private_data)
 702 {
 703         struct wait_for_read_state *state = talloc_get_type_abort(
 704                 private_data, struct wait_for_read_state);
 705
 706         if (flags & TEVENT_FD_READ) {
 707                 TALLOC_FREE(state->fde);
 708                 tevent_req_done(state->req);
 709         }
 710 }
 711
 712 bool wait_for_read_recv(struct tevent_req *req, int *perr)
 713 {
 714         int err;
 715
 716         if (tevent_req_is_unix_error(req, &err)) {
 717                 *perr = err;
 718                 return false;
 719         }
 720         return true;
 721 }