io.c 14.7 KB
Newer Older
Niels Möller's avatar
Niels Möller committed
1 2
/* io.c
 *
3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23
 *
 *
 * $Id$ */

/* lsh, an implementation of the ssh protocol
 *
 * Copyright (C) 1998 Niels Mller
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
Niels Möller's avatar
Niels Möller committed
24 25
 */

Niels Möller's avatar
Niels Möller committed
26 27 28
#include <assert.h>
#include <string.h>

Niels Möller's avatar
Niels Möller committed
29
#include <unistd.h>
30 31

#ifdef HAVE_POLL
Niels Möller's avatar
Niels Möller committed
32
#include <poll.h>
33 34 35 36
#else
#include "poll.h"
#endif

Niels Möller's avatar
Niels Möller committed
37 38 39 40
#include <errno.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/socket.h>
Niels Möller's avatar
Niels Möller committed
41
#include <arpa/inet.h>
42
#include <signal.h>
Niels Möller's avatar
Niels Möller committed
43

Niels Möller's avatar
Niels Möller committed
44 45 46 47 48
#include "io.h"
#include "werror.h"
#include "write_buffer.h"
#include "xalloc.h"

49 50 51 52 53 54
#define CLASS_DEFINE
#include "io.h.x"
#undef CLASS_DEFINE

#include "io.c.x"

Niels Möller's avatar
Niels Möller committed
55 56 57 58 59
/* If there's nothing to do for this amount of time (ms), do
 * spontaneous gc. */

#define IDLE_TIME 100

Niels Möller's avatar
Niels Möller committed
60 61 62 63 64
int io_iter(struct io_backend *b)
{
  unsigned long nfds; /* FIXME: Should be nfds_t if that type is defined */
  struct pollfd *fds;

Niels Möller's avatar
Niels Möller committed
65 66
  /* FIXME: Callouts not implemented */
  /* int timeout; */
Niels Möller's avatar
Niels Möller committed
67 68 69 70 71 72 73 74 75
  int res;

  nfds = 0;
  
  {
    /* Prepare fd:s. This fase calls the prepare-methods, also closes
     * and unlinks any fd:s that should be closed, and also counts how
     * many fd:s there are. */
    
Niels Möller's avatar
Niels Möller committed
76
    struct lsh_fd **fd_p;
Niels Möller's avatar
Niels Möller committed
77 78
    struct lsh_fd *fd;
    
Niels Möller's avatar
Niels Möller committed
79
    for(fd_p = &b->files; (fd = *fd_p); )
Niels Möller's avatar
Niels Möller committed
80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105
      {
	if (!fd->close_now && fd->prepare)
	  PREPARE_FD(fd);
	
	if (fd->close_now)
	  {
	    if (fd->fd < 0)
	      /* Unlink the file object, but don't close any underlying file. */
	      ;
	    else
	      {
		/* Used by write fd:s to make sure that writing to its
		 * buffer fails. */
		if (fd->really_close)
		  REALLY_CLOSE_FD(fd);
		
		/* FIXME: The value returned from the close callback could be used
		 * to choose an exit code. */
		if (fd->close_callback && fd->close_reason)
		  (void) CLOSE_CALLBACK(fd->close_callback, fd->close_reason);
		
		debug("Closing fd %d.\n", fd->fd);
		
		close(fd->fd);
	      }
	    /* Unlink this fd */
Niels Möller's avatar
Niels Möller committed
106
	    *fd_p = fd->next;
Niels Möller's avatar
Niels Möller committed
107 108 109
	    continue;
	  }
	nfds++;
Niels Möller's avatar
Niels Möller committed
110
	fd_p = &fd->next;
Niels Möller's avatar
Niels Möller committed
111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153
      }
	
  }

  if (!nfds)
    /* Nothing more to do.
     *
     * NOTE: There might be some callouts left, but we won't wait for them. */
    return 0;
  
  fds = alloca(sizeof(struct pollfd) * nfds);

  /* Fill out fds-array */
  {
    struct lsh_fd *fd;
    int i;
    int all_events = 0;
    
    for (fd = b->files, i = 0; fd; fd = fd->next, i++)
      {
	assert(i < nfds);

	fds[i].fd = fd->fd;
	fds[i].events = 0;

	if (fd->want_read)
	  fds[i].events |= POLLIN;

	if (fd->want_write)
	  fds[i].events |= POLLOUT;

	all_events |= fds[i].events;
      }
    assert(i == nfds);

    if (!all_events)
      {
	/* Nothing happens */
	/* NOTE: There might be some callouts left, but we don't wait */
	return 0;
      }
  }

Niels Möller's avatar
Niels Möller committed
154
  res = poll(fds, nfds, IDLE_TIME);
Niels Möller's avatar
Niels Möller committed
155

Niels Möller's avatar
Niels Möller committed
156 157 158 159 160 161
  if (!res)
    {
      gc_maybe(&b->super, 0);
      res = poll(fds, nfds, -1);
    }
  
Niels Möller's avatar
Niels Möller committed
162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204
  if (!res)
    {
      /* Callouts are not implemented */
      fatal("Unexpected timeout\n");
    }
  if (res < 0)
    switch(errno)
      {
      case EAGAIN:
      case EINTR:
	return 1;
      default:
	fatal("io_iter: poll failed: %s", strerror(errno));
      }
  
  {
    /* Do io. Note that the callback functions may add new fds to the
     * head of the list, or set the close_now flag on any fd. */

    struct lsh_fd *fd;
    int i;
    
    for(fd = b->files, i=0; fd; fd = fd->next, i++)
      {
	assert(i<nfds);
	
	if (fd->close_now)
	  continue;

	if (fds[i].revents & POLLOUT)
	  WRITE_FD(fd);

	if (fd->close_now)
	  continue;

	if (fds[i].revents & POLLIN)
	  READ_FD(fd);
      }
    assert(i == nfds);
  }

  return 1;
}
Niels Möller's avatar
Niels Möller committed
205

206 207 208 209 210 211 212 213
/* CLASS:
   (class
     (name fd_read)
     (super abstract_read)
       (vars
         (fd simple int)))
*/

Niels Möller's avatar
Niels Möller committed
214
static int do_read(struct abstract_read **r, UINT32 length, UINT8 *buffer)
Niels Möller's avatar
Niels Möller committed
215
{
216
  CAST(fd_read, closure, *r);
217

218 219 220 221
  while(1)
    {
      int res = read(closure->fd, buffer, length);
      if (!res)
Niels Möller's avatar
Niels Möller committed
222 223 224 225
	{
	  debug("Read EOF on fd %d.\n", closure->fd);
	  return A_EOF;
	}
226 227
      if (res > 0)
	return res;
228

229 230 231
      switch(errno)
	{
	case EINTR:
232 233
	  continue;  /* FIXME: Is it really worth looping here,
		      * instead of in the select loop? */
234 235
	case EWOULDBLOCK:  /* aka EAGAIN */
	  return 0;
Niels Möller's avatar
Niels Möller committed
236 237 238
	case EPIPE:
	  werror("io.c: read() returned EPIPE! Treating it as EOF.\n");
	  return A_EOF;
239
	default:
Niels Möller's avatar
Niels Möller committed
240 241 242 243
	  werror("io.c: do_read: read() failed (errno %d), %s\n",
		 errno, strerror(errno));
	  debug("  fd = %d, buffer = %p, length = %ud\n",
		closure->fd, buffer, length);
244 245 246 247
	  return A_FAIL;
	}
    }
}
Niels Möller's avatar
Niels Möller committed
248

Niels Möller's avatar
Niels Möller committed
249
static void read_callback(struct lsh_fd *fd)
250
{
251
  CAST(io_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
252
  int res;
253

Niels Möller's avatar
Niels Möller committed
254 255
  struct fd_read r =
  { { STACK_HEADER, do_read }, fd->fd };
256

Niels Möller's avatar
Niels Möller committed
257 258 259
  /* The handler function may install a new handler */
  res = READ_HANDLER(self->handler,
		     &r.super);
260

Niels Möller's avatar
Niels Möller committed
261 262
  /* NOTE: These flags are not mutually exclusive. All combination
   * must be handled correctly. */
263
  
Niels Möller's avatar
Niels Möller committed
264 265
  /* NOTE: (i) If LSH_DIE is set, LSH_CLOSE is ignored. (ii) If the fd
   * is read_only, LSH_CLOSE is the same as LSH_DIE. */
266

Niels Möller's avatar
Niels Möller committed
267 268
  /* This condition must be taken care of earlier. */
  assert(!(res & LSH_CHANNEL_FINISHED));
269

Niels Möller's avatar
Niels Möller committed
270 271
  /* Not implemented */
  assert(!(res & LSH_KILL_OTHERS));
272

Niels Möller's avatar
Niels Möller committed
273
  if (res & LSH_HOLD)
274
    {
Niels Möller's avatar
Niels Möller committed
275 276 277
      /* This flag should not be combined with anything else */
      assert(res == LSH_HOLD);
      fd->want_read = 0;
278
    }
Niels Möller's avatar
Niels Möller committed
279
  if (res & LSH_DIE)
Niels Möller's avatar
Niels Möller committed
280
    {
Niels Möller's avatar
Niels Möller committed
281 282 283 284 285 286
      if (self->buffer)
	write_buffer_close(self->buffer);
		  
      fd->close_reason = LSH_FAILUREP(res)
	? CLOSE_PROTOCOL_FAILURE : 0;
      fd->close_now = 1;
287
    }
Niels Möller's avatar
Niels Möller committed
288
  else if (res & LSH_CLOSE)
289
    {
Niels Möller's avatar
Niels Möller committed
290 291 292 293 294 295 296 297 298 299 300 301 302
      if (self->buffer)
	{
	  write_buffer_close(self->buffer);
	  /* Don't attempt to read any further. */
	  /* FIXME: Is it safe to free the handler here? */
	  self->super.want_read = 0;
	  self->handler = NULL;
	}
      else
	fd->close_now = 1;
		  
      fd->close_reason
	= LSH_FAILUREP(res) ? CLOSE_PROTOCOL_FAILURE : CLOSE_EOF;
303
    }
Niels Möller's avatar
Niels Möller committed
304
}
305

Niels Möller's avatar
Niels Möller committed
306 307
static void write_callback(struct lsh_fd *fd)
{
308
  CAST(io_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342
  UINT32 size;
  int res;
  
  size = MIN(self->buffer->end - self->buffer->start,
	     self->buffer->block_size);
  assert(size);
  
  res = write(fd->fd,
	      self->buffer->buffer + self->buffer->start,
	      size);
  if (!res)
    fatal("Closed?");
  if (res < 0)
    switch(errno)
      {
      case EINTR:
      case EAGAIN:
	break;
      case EPIPE:
	werror("Broken pipe\n");
	fd->close_reason = CLOSE_WRITE_FAILED;
	fd->close_now = 1;
	break;
      default:
	werror("io.c: write failed, %s\n", strerror(errno));

	fd->close_reason = CLOSE_WRITE_FAILED;
	fd->close_now = 1;
	
	break;
      }
  else
    self->buffer->start += res;
}  
343

Niels Möller's avatar
Niels Möller committed
344 345
static void listen_callback(struct lsh_fd *fd)
{
346
  CAST(listen_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
347 348 349 350
  struct sockaddr_in peer;
  size_t addr_len = sizeof(peer);
  int res;
  int conn;
351

Niels Möller's avatar
Niels Möller committed
352
  /* FIXME: Do something with the peer address? */
353

Niels Möller's avatar
Niels Möller committed
354 355 356
  conn = accept(fd->fd,
		(struct sockaddr *) &peer, &addr_len);
  if (conn < 0)
357
    {
Niels Möller's avatar
Niels Möller committed
358 359
      werror("io.c: accept() failed, %s", strerror(errno));
      return;
360
    }
Niels Möller's avatar
Niels Möller committed
361 362
  res = FD_CALLBACK(self->callback, conn);
  if (LSH_ACTIONP(res))
363
    {
Niels Möller's avatar
Niels Möller committed
364 365 366 367 368
      werror("Strange: Accepted a connection, "
	     "but failed before writing anything.\n");
      fd->close_now = 1;
      fd->close_reason = LSH_FAILUREP(res) ? CLOSE_PROTOCOL_FAILURE
	: CLOSE_EOF;
369
    }
Niels Möller's avatar
Niels Möller committed
370
}
371

Niels Möller's avatar
Niels Möller committed
372 373
static void connect_callback(struct lsh_fd *fd)
{
374
  CAST(connect_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
375 376 377
  int res;
  
  res = FD_CALLBACK(self->callback, fd->fd);
378

Niels Möller's avatar
Niels Möller committed
379
  if (LSH_ACTIONP(res))
380
    {
Niels Möller's avatar
Niels Möller committed
381 382
      werror("Strange: Connected, "
	     "but failed before writing anything.\n");
383 384
    }
  else
Niels Möller's avatar
Niels Möller committed
385 386 387
    {
      /* To avoid actually closing the fd */
      fd->fd = -1;
388
    }
Niels Möller's avatar
Niels Möller committed
389
  fd->close_now = 1;
390 391
}

392
/* FIXME: Prehaps this function should return a suitable exit code? */
393 394
void io_run(struct io_backend *b)
{
Niels Möller's avatar
Niels Möller committed
395 396 397 398 399 400 401 402 403
  struct sigaction pipe;

  pipe.sa_handler = SIG_IGN;
  sigemptyset(&pipe.sa_mask);
  pipe.sa_flags = 0;
  pipe.sa_restorer = NULL;
  
  if (sigaction(SIGPIPE, &pipe, NULL) < 0)
    fatal("Failed to ignore SIGPIPE.\n");
404
  
405 406
  while(io_iter(b))
    ;
407 408
}

409 410
void init_backend(struct io_backend *b)
{
Niels Möller's avatar
Niels Möller committed
411 412 413 414
  b->files = NULL;
#if 0
  b->callouts = 0;
#endif
415 416
}

Niels Möller's avatar
Niels Möller committed
417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439
/* Initializes a file structure, and adds it to the backend's list. */
static void init_file(struct io_backend *b, struct lsh_fd *f, int fd)
{
  /* assert(fd); */
  f->fd = fd;
  f->close_reason = -1; /* Invalid reason */
  f->close_callback = NULL;

  f->prepare = NULL;

  f->want_read = 0;
  f->read = NULL;

  f->want_write = 0;
  f->write = NULL;

  f->close_now = 0;
  f->really_close = NULL;

  f->next = b->files;
  b->files = f;
}
    
440 441 442
/*
 * Fill in ADDR from HOST, SERVICE and PROTOCOL.
 * Supplying a null pointer for HOST means use INADDR_ANY.
443
 * Otherwise HOST is an numbers-and-dots ip-number or a dns name.
444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504
 *
 * PROTOCOL can be tcp or udp.
 *
 * Supplying a null pointer for SERVICE, means use port 0, i.e. no port.
 * 
 * Returns zero on errors, 1 if everything is ok.
 */
int
get_inaddr(struct sockaddr_in	* addr,
	   const char		* host,
	   const char		* service,
	   const char		* protocol)
{
  memset(addr, 0, sizeof *addr);
  addr->sin_family = AF_INET;

  /*
   *  Set host part of ADDR
   */
  if (host == NULL)
    addr->sin_addr.s_addr = INADDR_ANY;
  else
    {
      /* First check for numerical ip-number */
      addr->sin_addr.s_addr = inet_addr(host);
      if (addr->sin_addr.s_addr == (unsigned long)-1)
	{
	  struct hostent * hp;
	  
	  hp = gethostbyname(host);
	  if (hp == NULL)
	    return 0;
	  memcpy(&addr->sin_addr, hp->h_addr, hp->h_length);
	  addr->sin_family = hp->h_addrtype;
	}
    }

  /*
   *  Set port part of ADDR
   */
  if (service == NULL)
    addr->sin_port = htons(0);
  else
    {
      char		* end;
      long		  portno;

      portno = strtol(service, &end, 10);
      if (portno > 0  &&  portno <= 65535
	  &&  end != service  &&  *end == '\0')
	{
	  addr->sin_port = htons(portno);
	}
      else
	{
	  struct servent	* serv;

	  serv = getservbyname(service, "tcp");
	  if (serv == NULL)
	    return 0;
	  addr->sin_port = serv->s_port;
Niels Möller's avatar
Niels Möller committed
505 506
	}
    }
507 508

  return 1;
Niels Möller's avatar
Niels Möller committed
509 510 511 512 513 514 515 516
}

void io_set_nonblocking(int fd)
{
  if (fcntl(fd, F_SETFL, O_NONBLOCK) < 0)
    fatal("io_set_nonblocking: fcntl() failed, %s", strerror(errno));
}

517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532
void io_set_close_on_exec(int fd)
{
  if (fcntl(fd, F_SETFD, 1) < 0)
    fatal("Can't set close-on-exec flag for fd %d: %s\n",
	  fd, strerror(errno));
}

/* ALL file descripters handled by the backend should use non-blocking mode,
 * and have the close-on-exec flag set. */

void io_init_fd(int fd)
{
  io_set_nonblocking(fd);
  io_set_close_on_exec(fd);
}

533 534 535 536 537
/* Some code is taken from bellman's tcputils. */
struct connect_fd *io_connect(struct io_backend *b,
			      struct sockaddr_in *remote,
			      struct sockaddr_in *local,
			      struct fd_callback *f)
Niels Möller's avatar
Niels Möller committed
538
{
539
  int s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
Niels Möller's avatar
Niels Möller committed
540
  
541 542
  if (s<0)
    return NULL;
Niels Möller's avatar
Niels Möller committed
543

544 545
  debug("io.c: connecting using fd %d\n", s);
  
546
  io_init_fd(s);
Niels Möller's avatar
Niels Möller committed
547

548 549 550 551 552 553 554
  if (local  &&  bind(s, (struct sockaddr *)local, sizeof *local) < 0)
    {
      int saved_errno = errno;
      close(s);
      errno = saved_errno;
      return NULL;
    }
Niels Möller's avatar
Niels Möller committed
555

556 557 558 559 560 561 562 563 564
  if ( (connect(s, (struct sockaddr *)remote, sizeof *remote) < 0)
       && (errno != EINPROGRESS) )       
    {
      int saved_errno = errno;
      close(s);
      errno = saved_errno;
      return NULL;
    }

565 566 567 568
  {
    NEW(connect_fd, fd);

    init_file(b, &fd->super, s);
Niels Möller's avatar
Niels Möller committed
569

570 571 572 573 574 575
    fd->super.want_write = 1;
    fd->super.write = connect_callback;
    fd->callback = f;
    
    return fd;
  }
Niels Möller's avatar
Niels Möller committed
576 577
}

578 579 580 581 582
struct listen_fd *io_listen(struct io_backend *b,
			    struct sockaddr_in *local,
			    struct fd_callback *callback)
{
  int s = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
Niels Möller's avatar
Niels Möller committed
583
  
584 585 586
  if (s<0)
    return NULL;

587 588
  debug("io.c: listening on fd %d\n", s);
  
589
  io_init_fd(s);
590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607

  {
    int yes = 1;
    setsockopt(s, SOL_SOCKET, SO_REUSEADDR, (char*)&yes, sizeof yes);
  }

  if (bind(s, (struct sockaddr *)local, sizeof *local) < 0)
    {
      close(s);
      return NULL;
    }

  if (listen(s, 256) < 0) 
    {
      close(s);
      return NULL;
    }

608 609
  {
    NEW(listen_fd, fd);
610

611 612 613 614 615 616 617 618
    init_file(b, &fd->super, s);
    
    fd->super.want_read = 1;
    fd->super.read = listen_callback;
    fd->callback = callback;
    
    return fd;
  }
619 620
}

Niels Möller's avatar
Niels Möller committed
621 622
static void really_close(struct lsh_fd *fd)
{
623
  CAST(io_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
624 625 626 627 628 629 630 631

  assert(self->buffer);

  write_buffer_close(self->buffer);
}

static void prepare_write(struct lsh_fd *fd)
{
632
  CAST(io_fd, self, fd);
Niels Möller's avatar
Niels Möller committed
633 634 635 636 637 638 639 640

  assert(self->buffer);

  if (! (fd->want_write = write_buffer_pre_write(self->buffer))
      && self->buffer->closed)
    fd->close_now = 1;
}
  
Niels Möller's avatar
Niels Möller committed
641 642
struct abstract_write *io_read_write(struct io_backend *b,
				     int fd,
Niels Möller's avatar
Niels Möller committed
643
				     struct read_handler *handler,
Niels Möller's avatar
Niels Möller committed
644
				     UINT32 block_size,
645
				     struct close_callback *close_callback)
646
{
647
  NEW(io_fd, f);
648
  struct write_buffer *buffer = write_buffer_alloc(block_size);
Niels Möller's avatar
Niels Möller committed
649

650 651
  debug("io.c: Preparing fd %d for reading and writing\n", fd);
  
652 653
  io_init_fd(fd);
  
Niels Möller's avatar
Niels Möller committed
654
  init_file(b, &f->super, fd);
655
  
656
  /* Reading */
Niels Möller's avatar
Niels Möller committed
657 658 659
  f->super.read = read_callback;
  f->super.want_read = !!handler;
  f->handler = handler;
660 661

  /* Writing */
Niels Möller's avatar
Niels Möller committed
662 663
  f->super.prepare = prepare_write;
  f->super.write = write_callback;
Niels Möller's avatar
Niels Möller committed
664
  f->buffer = buffer;
665

Niels Möller's avatar
Niels Möller committed
666 667 668
  /* Closing */
  f->super.really_close = really_close;
  f->super.close_callback = close_callback;
669

670
  return &buffer->super;
671
}
672 673 674

struct io_fd *io_read(struct io_backend *b,
		      int fd,
Niels Möller's avatar
Niels Möller committed
675
		      struct read_handler *handler,
676 677
		      struct close_callback *close_callback)
{
678
  NEW(io_fd, f);
679

680 681
  debug("io.c: Preparing fd %d for reading\n", fd);
  
682 683
  io_init_fd(fd);

Niels Möller's avatar
Niels Möller committed
684
  init_file(b, &f->super, fd);
685

Niels Möller's avatar
Niels Möller committed
686 687 688 689
  /* Reading */
  f->super.want_read = !!handler;
  f->super.read = read_callback;
  f->handler = handler;
690

Niels Möller's avatar
Niels Möller committed
691
  f->super.close_callback = close_callback;
692 693 694 695

  return f;
}

696 697 698 699
struct io_fd *io_write(struct io_backend *b,
		       int fd,
		       UINT32 block_size,
		       struct close_callback *close_callback)
700
{
701
  NEW(io_fd, f);
702 703
  struct write_buffer *buffer = write_buffer_alloc(block_size);

704 705
  debug("io.c: Preparing fd %d for writing\n", fd);
  
706 707
  io_init_fd(fd);
  
Niels Möller's avatar
Niels Möller committed
708
  init_file(b, &f->super, fd);
709 710

  /* Writing */
Niels Möller's avatar
Niels Möller committed
711 712
  f->super.prepare = prepare_write;
  f->super.write = write_callback;
713
  f->buffer = buffer;
Niels Möller's avatar
Niels Möller committed
714 715
  
  f->super.close_callback = close_callback;
716

717
  return f;
718
}
Niels Möller's avatar
Niels Möller committed
719 720 721 722

/* Marks a file for closing, at the end of the current iteration.
 * FIXME: Could be generalized for other fd:s than read-write fds. */

723
void close_fd(struct lsh_fd *fd, int reason)
Niels Möller's avatar
Niels Möller committed
724
{
725
  debug("Marking fd %d for closing.\n", fd->fd);
726
  fd->close_reason = reason;
Niels Möller's avatar
Niels Möller committed
727 728
  fd->close_now = 1;
}