source3/lib/async_sock.c

   1 /*
   2    Unix SMB/CIFS implementation.
   3    async socket syscalls
   4    Copyright (C) Volker Lendecke 2008
   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
  22 /**
  23  * Discriminator for async_syscall_state
  24  */
  25 enum async_syscall_type {
  26         ASYNC_SYSCALL_SEND,
  27         ASYNC_SYSCALL_SENDALL,
  28         ASYNC_SYSCALL_RECV,
  29         ASYNC_SYSCALL_RECVALL,
  30         ASYNC_SYSCALL_CONNECT
  31 };
  32
  33 /**
  34  * Holder for syscall arguments and the result
  35  */
  36
  37 struct async_syscall_state {
  38         enum async_syscall_type syscall_type;
  39         struct fd_event *fde;
  40
  41         union {
  42                 struct param_send {
  43                         int fd;
  44                         const void *buffer;
  45                         size_t length;
  46                         int flags;
  47                 } param_send;
  48                 struct param_sendall {
  49                         int fd;
  50                         const void *buffer;
  51                         size_t length;
  52                         int flags;
  53                         size_t sent;
  54                 } param_sendall;
  55                 struct param_recv {
  56                         int fd;
  57                         void *buffer;
  58                         size_t length;
  59                         int flags;
  60                 } param_recv;
  61                 struct param_recvall {
  62                         int fd;
  63                         void *buffer;
  64                         size_t length;
  65                         int flags;
  66                         size_t received;
  67                 } param_recvall;
  68                 struct param_connect {
  69                         /**
  70                          * connect needs to be done on a nonblocking
  71                          * socket. Keep the old flags around
  72                          */
  73                         long old_sockflags;
  74                         int fd;
  75                         const struct sockaddr *address;
  76                         socklen_t address_len;
  77                 } param_connect;
  78         } param;
  79
  80         union {
  81                 ssize_t result_ssize_t;
  82                 size_t result_size_t;
  83                 int result_int;
  84         } result;
  85         int sys_errno;
  86 };
  87
  88 /**
  89  * @brief Create a new async syscall req
  90  * @param[in] mem_ctx   The memory context to hang the result off
  91  * @param[in] ev        The event context to work from
  92  * @param[in] type      Which syscall will this be
  93  * @param[in] pstate    Where to put the newly created private_data state
  94  * @retval The new request
  95  *
  96  * This is a helper function to prepare a new struct async_req with an
  97  * associated struct async_syscall_state. The async_syscall_state will be put
  98  * into the async_req as private_data.
  99  */
 100
 101 static struct async_req *async_syscall_new(TALLOC_CTX *mem_ctx,
 102                                            struct event_context *ev,
 103                                            enum async_syscall_type type,
 104                                            struct async_syscall_state **pstate)
 105 {
 106         struct async_req *result;
 107         struct async_syscall_state *state;
 108
 109         if (!async_req_setup(mem_ctx, &result, &state,
 110                              struct async_syscall_state)) {
 111                 return NULL;
 112         }
 113         state->syscall_type = type;
 114
 115         result->private_data = state;
 116
 117         *pstate = state;
 118
 119         return result;
 120 }
 121
 122 /**
 123  * @brief Create a new async syscall req based on a fd
 124  * @param[in] mem_ctx   The memory context to hang the result off
 125  * @param[in] ev        The event context to work from
 126  * @param[in] type      Which syscall will this be
 127  * @param[in] fd        The file descriptor we work on
 128  * @param[in] fde_flags EVENT_FD_READ/WRITE -- what are we interested in?
 129  * @param[in] fde_cb    The callback function for the file descriptor event
 130  * @param[in] pstate    Where to put the newly created private_data state
 131  * @retval The new request
 132  *
 133  * This is a helper function to prepare a new struct async_req with an
 134  * associated struct async_syscall_state and an associated file descriptor
 135  * event.
 136  */
 137
 138 static struct async_req *async_fde_syscall_new(
 139         TALLOC_CTX *mem_ctx,
 140         struct event_context *ev,
 141         enum async_syscall_type type,
 142         int fd,
 143         uint16_t fde_flags,
 144         void (*fde_cb)(struct event_context *ev,
 145                        struct fd_event *fde, uint16_t flags,
 146                        void *priv),
 147         struct async_syscall_state **pstate)
 148 {
 149         struct async_req *result;
 150         struct async_syscall_state *state;
 151
 152         result = async_syscall_new(mem_ctx, ev, type, &state);
 153         if (result == NULL) {
 154                 return NULL;
 155         }
 156
 157         state->fde = event_add_fd(ev, state, fd, fde_flags, fde_cb, result);
 158         if (state->fde == NULL) {
 159                 TALLOC_FREE(result);
 160                 return NULL;
 161         }
 162         *pstate = state;
 163         return result;
 164 }
 165
 166 /**
 167  * Retrieve a ssize_t typed result from an async syscall
 168  * @param[in] req       The syscall that has just finished
 169  * @param[out] perrno   Where to put the syscall's errno
 170  * @retval The return value from the asynchronously called syscall
 171  */
 172
 173 ssize_t async_syscall_result_ssize_t(struct async_req *req, int *perrno)
 174 {
 175         struct async_syscall_state *state = talloc_get_type_abort(
 176                 req->private_data, struct async_syscall_state);
 177
 178         *perrno = state->sys_errno;
 179         return state->result.result_ssize_t;
 180 }
 181
 182 /**
 183  * Retrieve a size_t typed result from an async syscall
 184  * @param[in] req       The syscall that has just finished
 185  * @param[out] perrno   Where to put the syscall's errno
 186  * @retval The return value from the asynchronously called syscall
 187  */
 188
 189 size_t async_syscall_result_size_t(struct async_req *req, int *perrno)
 190 {
 191         struct async_syscall_state *state = talloc_get_type_abort(
 192                 req->private_data, struct async_syscall_state);
 193
 194         *perrno = state->sys_errno;
 195         return state->result.result_size_t;
 196 }
 197
 198 /**
 199  * Retrieve a int typed result from an async syscall
 200  * @param[in] req       The syscall that has just finished
 201  * @param[out] perrno   Where to put the syscall's errno
 202  * @retval The return value from the asynchronously called syscall
 203  */
 204
 205 int async_syscall_result_int(struct async_req *req, int *perrno)
 206 {
 207         struct async_syscall_state *state = talloc_get_type_abort(
 208                 req->private_data, struct async_syscall_state);
 209
 210         *perrno = state->sys_errno;
 211         return state->result.result_int;
 212 }
 213
 214 /**
 215  * fde event handler for the "send" syscall
 216  * @param[in] ev        The event context that sent us here
 217  * @param[in] fde       The file descriptor event associated with the send
 218  * @param[in] flags     Can only be EVENT_FD_WRITE here
 219  * @param[in] priv      private data, "struct async_req *" in this case
 220  */
 221
 222 static void async_send_callback(struct event_context *ev,
 223                                 struct fd_event *fde, uint16_t flags,
 224                                 void *priv)
 225 {
 226         struct async_req *req = talloc_get_type_abort(
 227                 priv, struct async_req);
 228         struct async_syscall_state *state = talloc_get_type_abort(
 229                 req->private_data, struct async_syscall_state);
 230         struct param_send *p = &state->param.param_send;
 231
 232         if (state->syscall_type != ASYNC_SYSCALL_SEND) {
 233                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 234                 return;
 235         }
 236
 237         state->result.result_ssize_t = send(p->fd, p->buffer, p->length,
 238                                             p->flags);
 239         state->sys_errno = errno;
 240
 241         TALLOC_FREE(state->fde);
 242
 243         async_req_done(req);
 244 }
 245
 246 /**
 247  * Async version of send(2)
 248  * @param[in] mem_ctx   The memory context to hang the result off
 249  * @param[in] ev        The event context to work from
 250  * @param[in] fd        The socket to send to
 251  * @param[in] buffer    The buffer to send
 252  * @param[in] length    How many bytes to send
 253  * @param[in] flags     flags passed to send(2)
 254  *
 255  * This function is a direct counterpart of send(2)
 256  */
 257
 258 struct async_req *async_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 259                              int fd, const void *buffer, size_t length,
 260                              int flags)
 261 {
 262         struct async_req *result;
 263         struct async_syscall_state *state;
 264
 265         result = async_fde_syscall_new(
 266                 mem_ctx, ev, ASYNC_SYSCALL_SEND,
 267                 fd, EVENT_FD_WRITE, async_send_callback,
 268                 &state);
 269         if (result == NULL) {
 270                 return NULL;
 271         }
 272
 273         state->param.param_send.fd = fd;
 274         state->param.param_send.buffer = buffer;
 275         state->param.param_send.length = length;
 276         state->param.param_send.flags = flags;
 277
 278         return result;
 279 }
 280
 281 /**
 282  * fde event handler for the "sendall" syscall group
 283  * @param[in] ev        The event context that sent us here
 284  * @param[in] fde       The file descriptor event associated with the send
 285  * @param[in] flags     Can only be EVENT_FD_WRITE here
 286  * @param[in] priv      private data, "struct async_req *" in this case
 287  */
 288
 289 static void async_sendall_callback(struct event_context *ev,
 290                                    struct fd_event *fde, uint16_t flags,
 291                                    void *priv)
 292 {
 293         struct async_req *req = talloc_get_type_abort(
 294                 priv, struct async_req);
 295         struct async_syscall_state *state = talloc_get_type_abort(
 296                 req->private_data, struct async_syscall_state);
 297         struct param_sendall *p = &state->param.param_sendall;
 298
 299         if (state->syscall_type != ASYNC_SYSCALL_SENDALL) {
 300                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 301                 return;
 302         }
 303
 304         state->result.result_ssize_t = send(p->fd, (char *)p->buffer + p->sent,
 305                                             p->length - p->sent, p->flags);
 306         state->sys_errno = errno;
 307
 308         if (state->result.result_ssize_t == -1) {
 309                 async_req_error(req, map_nt_error_from_unix(state->sys_errno));
 310                 return;
 311         }
 312
 313         if (state->result.result_ssize_t == 0) {
 314                 async_req_error(req, NT_STATUS_END_OF_FILE);
 315                 return;
 316         }
 317
 318         p->sent += state->result.result_ssize_t;
 319         if (p->sent > p->length) {
 320                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 321                 return;
 322         }
 323
 324         if (p->sent == p->length) {
 325                 TALLOC_FREE(state->fde);
 326                 async_req_done(req);
 327         }
 328 }
 329
 330 /**
 331  * @brief Send all bytes to a socket
 332  * @param[in] mem_ctx   The memory context to hang the result off
 333  * @param[in] ev        The event context to work from
 334  * @param[in] fd        The socket to send to
 335  * @param[in] buffer    The buffer to send
 336  * @param[in] length    How many bytes to send
 337  * @param[in] flags     flags passed to send(2)
 338  *
 339  * async_sendall calls send(2) as long as it is necessary to send all of the
 340  * "length" bytes
 341  */
 342
 343 struct async_req *sendall_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 344                                int fd, const void *buffer, size_t length,
 345                                int flags)
 346 {
 347         struct async_req *result;
 348         struct async_syscall_state *state;
 349
 350         result = async_fde_syscall_new(
 351                 mem_ctx, ev, ASYNC_SYSCALL_SENDALL,
 352                 fd, EVENT_FD_WRITE, async_sendall_callback,
 353                 &state);
 354         if (result == NULL) {
 355                 return NULL;
 356         }
 357
 358         state->param.param_sendall.fd = fd;
 359         state->param.param_sendall.buffer = buffer;
 360         state->param.param_sendall.length = length;
 361         state->param.param_sendall.flags = flags;
 362         state->param.param_sendall.sent = 0;
 363
 364         return result;
 365 }
 366
 367 NTSTATUS sendall_recv(struct async_req *req)
 368 {
 369         return async_req_simple_recv(req);
 370 }
 371
 372 /**
 373  * fde event handler for the "recv" syscall
 374  * @param[in] ev        The event context that sent us here
 375  * @param[in] fde       The file descriptor event associated with the recv
 376  * @param[in] flags     Can only be EVENT_FD_READ here
 377  * @param[in] priv      private data, "struct async_req *" in this case
 378  */
 379
 380 static void async_recv_callback(struct event_context *ev,
 381                                 struct fd_event *fde, uint16_t flags,
 382                                 void *priv)
 383 {
 384         struct async_req *req = talloc_get_type_abort(
 385                 priv, struct async_req);
 386         struct async_syscall_state *state = talloc_get_type_abort(
 387                 req->private_data, struct async_syscall_state);
 388         struct param_recv *p = &state->param.param_recv;
 389
 390         if (state->syscall_type != ASYNC_SYSCALL_RECV) {
 391                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 392                 return;
 393         }
 394
 395         state->result.result_ssize_t = recv(p->fd, p->buffer, p->length,
 396                                             p->flags);
 397         state->sys_errno = errno;
 398
 399         TALLOC_FREE(state->fde);
 400
 401         async_req_done(req);
 402 }
 403
 404 /**
 405  * Async version of recv(2)
 406  * @param[in] mem_ctx   The memory context to hang the result off
 407  * @param[in] ev        The event context to work from
 408  * @param[in] fd        The socket to recv from
 409  * @param[in] buffer    The buffer to recv into
 410  * @param[in] length    How many bytes to recv
 411  * @param[in] flags     flags passed to recv(2)
 412  *
 413  * This function is a direct counterpart of recv(2)
 414  */
 415
 416 struct async_req *async_recv(TALLOC_CTX *mem_ctx, struct event_context *ev,
 417                              int fd, void *buffer, size_t length,
 418                              int flags)
 419 {
 420         struct async_req *result;
 421         struct async_syscall_state *state;
 422
 423         result = async_fde_syscall_new(
 424                 mem_ctx, ev, ASYNC_SYSCALL_RECV,
 425                 fd, EVENT_FD_READ, async_recv_callback,
 426                 &state);
 427
 428         if (result == NULL) {
 429                 return NULL;
 430         }
 431
 432         state->param.param_recv.fd = fd;
 433         state->param.param_recv.buffer = buffer;
 434         state->param.param_recv.length = length;
 435         state->param.param_recv.flags = flags;
 436
 437         return result;
 438 }
 439
 440 /**
 441  * fde event handler for the "recvall" syscall group
 442  * @param[in] ev        The event context that sent us here
 443  * @param[in] fde       The file descriptor event associated with the recv
 444  * @param[in] flags     Can only be EVENT_FD_READ here
 445  * @param[in] priv      private data, "struct async_req *" in this case
 446  */
 447
 448 static void async_recvall_callback(struct event_context *ev,
 449                                    struct fd_event *fde, uint16_t flags,
 450                                    void *priv)
 451 {
 452         struct async_req *req = talloc_get_type_abort(
 453                 priv, struct async_req);
 454         struct async_syscall_state *state = talloc_get_type_abort(
 455                 req->private_data, struct async_syscall_state);
 456         struct param_recvall *p = &state->param.param_recvall;
 457
 458         if (state->syscall_type != ASYNC_SYSCALL_RECVALL) {
 459                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 460                 return;
 461         }
 462
 463         state->result.result_ssize_t = recv(p->fd,
 464                                             (char *)p->buffer + p->received,
 465                                             p->length - p->received, p->flags);
 466         state->sys_errno = errno;
 467
 468         if (state->result.result_ssize_t == -1) {
 469                 async_req_error(req, map_nt_error_from_unix(state->sys_errno));
 470                 return;
 471         }
 472
 473         if (state->result.result_ssize_t == 0) {
 474                 async_req_error(req, NT_STATUS_END_OF_FILE);
 475                 return;
 476         }
 477
 478         p->received += state->result.result_ssize_t;
 479         if (p->received > p->length) {
 480                 async_req_error(req, NT_STATUS_INTERNAL_ERROR);
 481                 return;
 482         }
 483
 484         if (p->received == p->length) {
 485                 TALLOC_FREE(state->fde);
 486                 async_req_done(req);
 487         }
 488 }
 489
 490 /**
 491  * Receive a specified number of bytes from a socket
 492  * @param[in] mem_ctx   The memory context to hang the result off
 493  * @param[in] ev        The event context to work from
 494  * @param[in] fd        The socket to recv from
 495  * @param[in] buffer    The buffer to recv into
 496  * @param[in] length    How many bytes to recv
 497  * @param[in] flags     flags passed to recv(2)
 498  *
 499  * async_recvall will call recv(2) until "length" bytes are received
 500  */
 501
 502 struct async_req *recvall_send(TALLOC_CTX *mem_ctx, struct event_context *ev,
 503                                int fd, void *buffer, size_t length,
 504                                int flags)
 505 {
 506         struct async_req *result;
 507         struct async_syscall_state *state;
 508
 509         result = async_fde_syscall_new(
 510                 mem_ctx, ev, ASYNC_SYSCALL_RECVALL,
 511                 fd, EVENT_FD_READ, async_recvall_callback,
 512                 &state);
 513         if (result == NULL) {
 514                 return NULL;
 515         }
 516
 517         state->param.param_recvall.fd = fd;
 518         state->param.param_recvall.buffer = buffer;
 519         state->param.param_recvall.length = length;
 520         state->param.param_recvall.flags = flags;
 521         state->param.param_recvall.received = 0;
 522
 523         return result;
 524 }
 525
 526 NTSTATUS recvall_recv(struct async_req *req)
 527 {
 528         return async_req_simple_recv(req);
 529 }
 530
 531 struct async_connect_state {
 532         int fd;
 533         int result;
 534         int sys_errno;
 535         long old_sockflags;
 536 };
 537
 538 static void async_connect_connected(struct event_context *ev,
 539                                     struct fd_event *fde, uint16_t flags,
 540                                     void *priv);
 541
 542 /**
 543  * @brief async version of connect(2)
 544  * @param[in] mem_ctx   The memory context to hang the result off
 545  * @param[in] ev        The event context to work from
 546  * @param[in] fd        The socket to recv from
 547  * @param[in] address   Where to connect?
 548  * @param[in] address_len Length of *address
 549  * @retval The async request
 550  *
 551  * This function sets the socket into non-blocking state to be able to call
 552  * connect in an async state. This will be reset when the request is finished.
 553  */
 554
 555 struct async_req *async_connect_send(TALLOC_CTX *mem_ctx,
 556                                      struct event_context *ev,
 557                                      int fd, const struct sockaddr *address,
 558                                      socklen_t address_len)
 559 {
 560         struct async_req *result;
 561         struct async_connect_state *state;
 562         struct fd_event *fde;
 563         NTSTATUS status;
 564
 565         if (!async_req_setup(mem_ctx, &result, &state,
 566                              struct async_connect_state)) {
 567                 return NULL;
 568         }
 569
 570         /**
 571          * We have to set the socket to nonblocking for async connect(2). Keep
 572          * the old sockflags around.
 573          */
 574
 575         state->fd = fd;
 576         state->sys_errno = 0;
 577
 578         state->old_sockflags = sys_fcntl_long(fd, F_GETFL, 0);
 579         if (state->old_sockflags == -1) {
 580                 goto post_errno;
 581         }
 582
 583         set_blocking(fd, false);
 584
 585         state->result = connect(fd, address, address_len);
 586         if (state->result == 0) {
 587                 state->sys_errno = 0;
 588                 status = NT_STATUS_OK;
 589                 goto post_status;
 590         }
 591
 592         /**
 593          * A number of error messages show that something good is progressing
 594          * and that we have to wait for readability.
 595          *
 596          * If none of them are present, bail out.
 597          */
 598
 599         if (!(errno == EINPROGRESS || errno == EALREADY ||
 600 #ifdef EISCONN
 601               errno == EISCONN ||
 602 #endif
 603               errno == EAGAIN || errno == EINTR)) {
 604                 goto post_errno;
 605         }
 606
 607         fde = event_add_fd(ev, state, fd, EVENT_FD_READ | EVENT_FD_WRITE,
 608                            async_connect_connected, result);
 609         if (fde == NULL) {
 610                 status = NT_STATUS_NO_MEMORY;
 611                 goto post_status;
 612         }
 613         return result;
 614
 615  post_errno:
 616         state->sys_errno = errno;
 617         status = map_nt_error_from_unix(state->sys_errno);
 618  post_status:
 619         sys_fcntl_long(fd, F_SETFL, state->old_sockflags);
 620         if (!async_post_status(result, ev, status)) {
 621                 goto fail;
 622         }
 623         return result;
 624  fail:
 625         TALLOC_FREE(result);
 626         return NULL;
 627 }
 628
 629 /**
 630  * fde event handler for connect(2)
 631  * @param[in] ev        The event context that sent us here
 632  * @param[in] fde       The file descriptor event associated with the connect
 633  * @param[in] flags     Indicate read/writeability of the socket
 634  * @param[in] priv      private data, "struct async_req *" in this case
 635  */
 636
 637 static void async_connect_connected(struct event_context *ev,
 638                                     struct fd_event *fde, uint16_t flags,
 639                                     void *priv)
 640 {
 641         struct async_req *req = talloc_get_type_abort(
 642                 priv, struct async_req);
 643         struct async_connect_state *state = talloc_get_type_abort(
 644                 req->private_data, struct async_connect_state);
 645
 646         TALLOC_FREE(fde);
 647
 648         /*
 649          * Stevens, Network Programming says that if there's a
 650          * successful connect, the socket is only writable. Upon an
 651          * error, it's both readable and writable.
 652          */
 653         if ((flags & (EVENT_FD_READ|EVENT_FD_WRITE))
 654             == (EVENT_FD_READ|EVENT_FD_WRITE)) {
 655                 int sockerr;
 656                 socklen_t err_len = sizeof(sockerr);
 657
 658                 if (getsockopt(state->fd, SOL_SOCKET, SO_ERROR,
 659                                (void *)&sockerr, &err_len) == 0) {
 660                         errno = sockerr;
 661                 }
 662
 663                 state->sys_errno = errno;
 664
 665                 DEBUG(10, ("connect returned %s\n", strerror(errno)));
 666
 667                 sys_fcntl_long(state->fd, F_SETFL, state->old_sockflags);
 668                 async_req_error(req, map_nt_error_from_unix(state->sys_errno));
 669                 return;
 670         }
 671
 672         state->sys_errno = 0;
 673         async_req_done(req);
 674 }
 675
 676 NTSTATUS async_connect_recv(struct async_req *req, int *perrno)
 677 {
 678         struct async_connect_state *state = talloc_get_type_abort(
 679                 req->private_data, struct async_connect_state);
 680         NTSTATUS status;
 681
 682         sys_fcntl_long(state->fd, F_SETFL, state->old_sockflags);
 683
 684         *perrno = state->sys_errno;
 685
 686         if (async_req_is_error(req, &status)) {
 687                 return status;
 688         }
 689         if (state->sys_errno == 0) {
 690                 return NT_STATUS_OK;
 691         }
 692         return map_nt_error_from_unix(state->sys_errno);
 693 }