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;
}