aboutsummaryrefslogtreecommitdiffstats
path: root/src/interface.c
blob: 7dbcd2dc331a3f88948015525a46e5903d69c068 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
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
106
107
108
109
110
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
154
155
156
157
158
159
160
161
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
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
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
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
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
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
/* the Music Player Daemon (MPD)
 * Copyright (C) 2003-2007 by Warren Dukes (warren.dukes@gmail.com)
 * This project's homepage is: http://www.musicpd.org
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */

#include "interface.h"
#include "command.h"
#include "conf.h"
#include "list.h"
#include "log.h"
#include "listen.h"
#include "playlist.h"
#include "permission.h"
#include "sllist.h"
#include "utils.h"
#include "ioops.h"
#include "os_compat.h"

#define GREETING				"OK MPD " PROTOCOL_VERSION "\n"

#define INTERFACE_MAX_BUFFER_LENGTH			(40960)
#define INTERFACE_LIST_MODE_BEGIN			"command_list_begin"
#define INTERFACE_LIST_OK_MODE_BEGIN			"command_list_ok_begin"
#define INTERFACE_LIST_MODE_END				"command_list_end"
#define INTERFACE_DEFAULT_OUT_BUFFER_SIZE		(4096)
#define INTERFACE_TIMEOUT_DEFAULT			(60)
#define INTERFACE_MAX_CONNECTIONS_DEFAULT		(10)
#define INTERFACE_MAX_COMMAND_LIST_DEFAULT		(2048*1024)
#define INTERFACE_MAX_OUTPUT_BUFFER_SIZE_DEFAULT	(8192*1024)

/* set this to zero to indicate we have no possible interfaces */
static int interface_max_connections;	/*INTERFACE_MAX_CONNECTIONS_DEFAULT; */
static int interface_timeout = INTERFACE_TIMEOUT_DEFAULT;
static size_t interface_max_command_list_size =
    INTERFACE_MAX_COMMAND_LIST_DEFAULT;
static size_t interface_max_output_buffer_size =
    INTERFACE_MAX_OUTPUT_BUFFER_SIZE_DEFAULT;

/* maybe make conf option for this, or... 32 might be good enough */
static long int interface_list_cache_size = 32;

/* shared globally between all interfaces: */
static struct strnode *list_cache;
static struct strnode *list_cache_head;
static struct strnode *list_cache_tail;

typedef struct _Interface {
	char buffer[INTERFACE_MAX_BUFFER_LENGTH];
	int bufferLength;
	int bufferPos;
	int fd;	/* file descriptor */
	int permission;
	time_t lastTime;
	struct strnode *cmd_list;	/* for when in list mode */
	struct strnode *cmd_list_tail;	/* for when in list mode */
	int cmd_list_OK;	/* print OK after each command execution */
	int cmd_list_size;	/* mem cmd_list consumes */
	int cmd_list_dup;	/* has the cmd_list been copied to private space? */
	struct sllnode *deferred_send;	/* for output if client is slow */
	int deferred_bytes;	/* mem deferred_send consumes */
	int expired;	/* set whether this interface should be closed on next
			   check of old interfaces */
	int num;	/* interface number */

	char *send_buf;
	int send_buf_used;	/* bytes used this instance */
	int send_buf_size;	/* bytes usable this instance */
	int send_buf_alloc;	/* bytes actually allocated */
} Interface;

static Interface *interfaces;

static void flushInterfaceBuffer(Interface * interface);

static void printInterfaceOutBuffer(Interface * interface);

#ifdef SO_SNDBUF
static int get_default_snd_buf_size(Interface * interface)
{
	int new_size;
	socklen_t sockOptLen = sizeof(int);

	if (getsockopt(interface->fd, SOL_SOCKET, SO_SNDBUF,
		       (char *)&new_size, &sockOptLen) < 0) {
		DEBUG("problem getting sockets send buffer size\n");
		return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
	}
	if (new_size > 0)
		return new_size;
	DEBUG("sockets send buffer size is not positive\n");
	return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
}
#else /* !SO_SNDBUF */
static int get_default_snd_buf_size(Interface * interface)
{
	return INTERFACE_DEFAULT_OUT_BUFFER_SIZE;
}
#endif /* !SO_SNDBUF */

static void set_send_buf_size(Interface * interface)
{
	int new_size = get_default_snd_buf_size(interface);
	if (interface->send_buf_size != new_size) {
		interface->send_buf_size = new_size;
		/* don't resize to get smaller, only bigger */
		if (interface->send_buf_alloc < new_size) {
			if (interface->send_buf)
				free(interface->send_buf);
			interface->send_buf = xmalloc(new_size);
			interface->send_buf_alloc = new_size;
		}
	}
}

static void openInterface(Interface * interface, int fd)
{
	int flags;

	assert(interface->fd < 0);

	interface->cmd_list_size = 0;
	interface->cmd_list_dup = 0;
	interface->cmd_list_OK = -1;
	interface->bufferLength = 0;
	interface->bufferPos = 0;
	interface->fd = fd;
	while ((flags = fcntl(fd, F_GETFL)) < 0 && errno == EINTR) ;
	while (fcntl(fd, F_SETFL, flags | O_NONBLOCK) < 0 && errno == EINTR) ;
	interface->lastTime = time(NULL);
	interface->cmd_list = NULL;
	interface->cmd_list_tail = NULL;
	interface->deferred_send = NULL;
	interface->expired = 0;
	interface->deferred_bytes = 0;
	interface->send_buf_used = 0;

	interface->permission = getDefaultPermissions();
	set_send_buf_size(interface);

	xwrite(fd, GREETING, strlen(GREETING));
}

static void free_cmd_list(struct strnode *list)
{
	struct strnode *tmp = list;

	while (tmp) {
		struct strnode *next = tmp->next;
		if (tmp >= list_cache_head && tmp <= list_cache_tail) {
			/* inside list_cache[] array */
			tmp->data = NULL;
			tmp->next = NULL;
		} else
			free(tmp);
		tmp = next;
	}
}

static void cmd_list_clone(Interface * interface)
{
	struct strnode *new = dup_strlist(interface->cmd_list);
	free_cmd_list(interface->cmd_list);
	interface->cmd_list = new;
	interface->cmd_list_dup = 1;

	/* new tail */
	while (new && new->next)
		new = new->next;
	interface->cmd_list_tail = new;
}

static void new_cmd_list_ptr(Interface * interface, char *s, const int size)
{
	int i;
	struct strnode *new;

	if (!interface->cmd_list_dup) {
		for (i = interface_list_cache_size - 1; i >= 0; --i) {
			if (list_cache[i].data)
				continue;
			new = &(list_cache[i]);
			new->data = s;
			/* implied in free_cmd_list() and init: */
			/* last->next->next = NULL; */
			goto out;
		}
	}

	/* allocate from the heap */
	new = interface->cmd_list_dup ? new_strnode_dup(s, size)
	                              : new_strnode(s);
out:
	if (interface->cmd_list) {
		interface->cmd_list_tail->next = new;
		interface->cmd_list_tail = new;
	} else
		interface->cmd_list = interface->cmd_list_tail = new;
}

static void closeInterface(Interface * interface)
{
	struct sllnode *buf;
	if (interface->fd < 0)
		return;
	xclose(interface->fd);
	interface->fd = -1;

	if (interface->cmd_list) {
		free_cmd_list(interface->cmd_list);
		interface->cmd_list = NULL;
	}

	if ((buf = interface->deferred_send)) {
		do {
			struct sllnode *prev = buf;
			buf = buf->next;
			free(prev);
		} while (buf);
		interface->deferred_send = NULL;
	}

	SECURE("interface %i: closed\n", interface->num);
}

void openAInterface(int fd, struct sockaddr *addr)
{
	int i;

	for (i = 0; i < interface_max_connections
	     && interfaces[i].fd >= 0; i++) /* nothing */ ;

	if (i == interface_max_connections) {
		ERROR("Max Connections Reached!\n");
		xclose(fd);
	} else {
		const char *hostname;
		switch (addr->sa_family) {
		case AF_INET:
			hostname = (const char *)inet_ntoa(((struct sockaddr_in *)
			                                    addr)->sin_addr);
			if (!hostname)
				hostname = "error getting ipv4 address";
			break;
#ifdef HAVE_IPV6
		case AF_INET6:
			{
				static char host[INET6_ADDRSTRLEN + 1];
				memset(host, 0, INET6_ADDRSTRLEN + 1);
				if (inet_ntop(AF_INET6, (void *)
					      &(((struct sockaddr_in6 *)addr)->
						sin6_addr), host,
					      INET6_ADDRSTRLEN)) {
					hostname = (const char *)host;
				} else {
					hostname = "error getting ipv6 address";
				}
			}
			break;
#endif
		case AF_UNIX:
			hostname = "local connection";
			break;
		default:
			hostname = "unknown";
		}
		SECURE("interface %i: opened from %s\n", i, hostname);
		openInterface(&(interfaces[i]), fd);
	}
}

static int processLineOfInput(Interface * interface)
{
	int ret = 1;
	char *line = interface->buffer + interface->bufferPos;

	if (interface->cmd_list_OK >= 0) {
		if (strcmp(line, INTERFACE_LIST_MODE_END) == 0) {
			DEBUG("interface %i: process command "
			      "list\n", interface->num);
			ret = processListOfCommands(interface->fd,
						    &(interface->permission),
						    &(interface->expired),
						    interface->cmd_list_OK,
						    interface->cmd_list);
			DEBUG("interface %i: process command "
			      "list returned %i\n", interface->num, ret);
			if (ret == 0)
				commandSuccess(interface->fd);
			else if (ret == COMMAND_RETURN_CLOSE
				 || interface->expired)
				closeInterface(interface);

			printInterfaceOutBuffer(interface);
			free_cmd_list(interface->cmd_list);
			interface->cmd_list = NULL;
			interface->cmd_list_OK = -1;
		} else {
			size_t len = strlen(line) + 1;
			interface->cmd_list_size += len;
			if (interface->cmd_list_size >
			    interface_max_command_list_size) {
				ERROR("interface %i: command "
				      "list size (%i) is "
				      "larger than the max "
				      "(%li)\n",
				      interface->num,
				      interface->cmd_list_size,
				      (long)interface_max_command_list_size);
				closeInterface(interface);
				ret = COMMAND_RETURN_CLOSE;
			} else
				new_cmd_list_ptr(interface, line, len);
		}
	} else {
		if (strcmp(line, INTERFACE_LIST_MODE_BEGIN) == 0) {
			interface->cmd_list_OK = 0;
			ret = 1;
		} else if (strcmp(line, INTERFACE_LIST_OK_MODE_BEGIN) == 0) {
			interface->cmd_list_OK = 1;
			ret = 1;
		} else {
			DEBUG("interface %i: process command \"%s\"\n",
			      interface->num, line);
			ret = processCommand(interface->fd,
					     &(interface->permission), line);
			DEBUG("interface %i: command returned %i\n",
			      interface->num, ret);
			if (ret == 0)
				commandSuccess(interface->fd);
			else if (ret == COMMAND_RETURN_CLOSE
				 || interface->expired) {
				closeInterface(interface);
			}
			printInterfaceOutBuffer(interface);
		}
	}

	return ret;
}

static int processBytesRead(Interface * interface, int bytesRead)
{
	int ret = 0;
	char *buf_tail = &(interface->buffer[interface->bufferLength - 1]);

	while (bytesRead > 0) {
		interface->bufferLength++;
		bytesRead--;
		buf_tail++;
		if (*buf_tail == '\n') {
			*buf_tail = '\0';
			if (interface->bufferLength - interface->bufferPos > 1) {
				if (*(buf_tail - 1) == '\r')
					*(buf_tail - 1) = '\0';
			}
			ret = processLineOfInput(interface);
			if (interface->expired)
				return ret;
			interface->bufferPos = interface->bufferLength;
		}
		if (interface->bufferLength == INTERFACE_MAX_BUFFER_LENGTH) {
			if (interface->bufferPos == 0) {
				ERROR("interface %i: buffer overflow\n",
				      interface->num);
				closeInterface(interface);
				return 1;
			}
			if (interface->cmd_list_OK >= 0 &&
			    interface->cmd_list &&
			    !interface->cmd_list_dup)
				cmd_list_clone(interface);
			interface->bufferLength -= interface->bufferPos;
			memmove(interface->buffer,
				interface->buffer + interface->bufferPos,
				interface->bufferLength);
			interface->bufferPos = 0;
		}
		if (ret == COMMAND_RETURN_KILL || ret == COMMAND_RETURN_CLOSE) {
			return ret;
		}

	}

	return ret;
}

static int interfaceReadInput(Interface * interface)
{
	int bytesRead;

	bytesRead = read(interface->fd,
			 interface->buffer + interface->bufferLength,
			 INTERFACE_MAX_BUFFER_LENGTH - interface->bufferLength);

	if (bytesRead > 0)
		return processBytesRead(interface, bytesRead);
	else if (bytesRead == 0 || (bytesRead < 0 && errno != EINTR)) {
		closeInterface(interface);
	} else
		return 0;

	return 1;
}

static void addInterfacesReadyToReadAndListenSocketToFdSet(fd_set * fds,
							   int *fdmax)
{
	int i;

	FD_ZERO(fds);
	addListenSocketsToFdSet(fds, fdmax);

	for (i = 0; i < interface_max_connections; i++) {
		if (interfaces[i].fd >= 0 && !interfaces[i].expired
		    && !interfaces[i].deferred_send) {
			FD_SET(interfaces[i].fd, fds);
			if (*fdmax < interfaces[i].fd)
				*fdmax = interfaces[i].fd;
		}
	}
}

static void addInterfacesForBufferFlushToFdSet(fd_set * fds, int *fdmax)
{
	int i;

	FD_ZERO(fds);

	for (i = 0; i < interface_max_connections; i++) {
		if (interfaces[i].fd >= 0 && !interfaces[i].expired
		    && interfaces[i].deferred_send) {
			FD_SET(interfaces[i].fd, fds);
			if (*fdmax < interfaces[i].fd)
				*fdmax = interfaces[i].fd;
		}
	}
}

static void closeNextErroredInterface(void)
{
	fd_set fds;
	struct timeval tv;
	int i;

	tv.tv_sec = 0;
	tv.tv_usec = 0;

	for (i = 0; i < interface_max_connections; i++) {
		if (interfaces[i].fd >= 0) {
			FD_ZERO(&fds);
			FD_SET(interfaces[i].fd, &fds);
			if (select(FD_SETSIZE, &fds, NULL, NULL, &tv) < 0) {
				closeInterface(&interfaces[i]);
				return;
			}
		}
	}
}

int doIOForInterfaces(void)
{
	fd_set rfds;
	fd_set wfds;
	fd_set efds;
	struct timeval tv;
	int i;
	int selret;
	int fdmax;

	tv.tv_sec = 1;
	tv.tv_usec = 0;

	while (1) {
		fdmax = 0;

		FD_ZERO( &efds );
		addInterfacesReadyToReadAndListenSocketToFdSet(&rfds, &fdmax);
		addInterfacesForBufferFlushToFdSet(&wfds, &fdmax);

		registered_IO_add_fds(&fdmax, &rfds, &wfds, &efds);

		selret = select(fdmax + 1, &rfds, &wfds, &efds, &tv);

		if (selret < 0 && errno == EINTR)
			break;

		registered_IO_consume_fds(&selret, &rfds, &wfds, &efds);

		if (selret == 0)
			break;

		if (selret < 0) {
			closeNextErroredInterface();
			continue;
		}

		getConnections(&rfds);

		for (i = 0; i < interface_max_connections; i++) {
			if (interfaces[i].fd >= 0
			    && FD_ISSET(interfaces[i].fd, &rfds)) {
				if (COMMAND_RETURN_KILL ==
				    interfaceReadInput(&(interfaces[i]))) {
					return COMMAND_RETURN_KILL;
				}
				interfaces[i].lastTime = time(NULL);
			}
			if (interfaces[i].fd >= 0
			    && FD_ISSET(interfaces[i].fd, &wfds)) {
				flushInterfaceBuffer(&interfaces[i]);
				interfaces[i].lastTime = time(NULL);
			}
		}

		tv.tv_sec = 0;
		tv.tv_usec = 0;
	}

	return 1;
}

void initInterfaces(void)
{
	int i;
	char *test;
	ConfigParam *param;

	param = getConfigParam(CONF_CONN_TIMEOUT);

	if (param) {
		interface_timeout = strtol(param->value, &test, 10);
		if (*test != '\0' || interface_timeout <= 0) {
			FATAL("connection timeout \"%s\" is not a positive "
			      "integer, line %i\n", CONF_CONN_TIMEOUT,
			      param->line);
		}
	}

	param = getConfigParam(CONF_MAX_CONN);

	if (param) {
		interface_max_connections = strtol(param->value, &test, 10);
		if (*test != '\0' || interface_max_connections <= 0) {
			FATAL("max connections \"%s\" is not a positive integer"
			      ", line %i\n", param->value, param->line);
		}
	} else
		interface_max_connections = INTERFACE_MAX_CONNECTIONS_DEFAULT;

	param = getConfigParam(CONF_MAX_COMMAND_LIST_SIZE);

	if (param) {
		interface_max_command_list_size = strtol(param->value,
							 &test, 10);
		if (*test != '\0' || interface_max_command_list_size <= 0) {
			FATAL("max command list size \"%s\" is not a positive "
			      "integer, line %i\n", param->value, param->line);
		}
		interface_max_command_list_size *= 1024;
	}

	param = getConfigParam(CONF_MAX_OUTPUT_BUFFER_SIZE);

	if (param) {
		interface_max_output_buffer_size = strtol(param->value,
		                                          &test, 10);
		if (*test != '\0' || interface_max_output_buffer_size <= 0) {
			FATAL("max output buffer size \"%s\" is not a positive "
			      "integer, line %i\n", param->value, param->line);
		}
		interface_max_output_buffer_size *= 1024;
	}

	interfaces = xmalloc(sizeof(Interface) * interface_max_connections);

	list_cache = xcalloc(interface_list_cache_size, sizeof(struct strnode));
	list_cache_head = &(list_cache[0]);
	list_cache_tail = &(list_cache[interface_list_cache_size - 1]);

	for (i = 0; i < interface_max_connections; i++) {
		interfaces[i].fd = -1;
		interfaces[i].send_buf = NULL;
		interfaces[i].send_buf_size = 0;
		interfaces[i].send_buf_alloc = 0;
		interfaces[i].num = i;
	}
}

static void closeAllInterfaces(void)
{
	int i;

	for (i = 0; i < interface_max_connections; i++) {
		if (interfaces[i].fd > 0)
			closeInterface(&(interfaces[i]));
		if (interfaces[i].send_buf)
			free(interfaces[i].send_buf);
	}
	free(list_cache);
}

void freeAllInterfaces(void)
{
	closeAllInterfaces();

	free(interfaces);

	interface_max_connections = 0;
}

void closeOldInterfaces(void)
{
	int i;

	for (i = 0; i < interface_max_connections; i++) {
		if (interfaces[i].fd > 0) {
			if (interfaces[i].expired) {
				DEBUG("interface %i: expired\n", i);
				closeInterface(&(interfaces[i]));
			} else if (time(NULL) - interfaces[i].lastTime >
				   interface_timeout) {
				DEBUG("interface %i: timeout\n", i);
				closeInterface(&(interfaces[i]));
			}
		}
	}
}

static void flushInterfaceBuffer(Interface * interface)
{
	struct sllnode *buf;
	int ret = 0;

	buf = interface->deferred_send;
	while (buf) {
		ret = write(interface->fd, buf->data, buf->size);
		if (ret < 0)
			break;
		else if (ret < buf->size) {
			interface->deferred_bytes -= ret;
			buf->data = (char *)buf->data + ret;
			buf->size -= ret;
		} else {
			struct sllnode *tmp = buf;
			interface->deferred_bytes -= (buf->size +
						      sizeof(struct sllnode));
			buf = buf->next;
			free(tmp);
			interface->deferred_send = buf;
		}
		interface->lastTime = time(NULL);
	}

	if (!interface->deferred_send) {
		DEBUG("interface %i: buffer empty %i\n", interface->num,
		      interface->deferred_bytes);
		assert(interface->deferred_bytes == 0);
	} else if (ret < 0 && errno != EAGAIN && errno != EINTR) {
		/* cause interface to close */
		DEBUG("interface %i: problems flushing buffer\n",
		      interface->num);
		buf = interface->deferred_send;
		do {
			struct sllnode *prev = buf;
			buf = buf->next;
			free(prev);
		} while (buf);
		interface->deferred_send = NULL;
		interface->deferred_bytes = 0;
		interface->expired = 1;
	}
}

int interfacePrintWithFD(int fd, char *buffer, int buflen)
{
	static int i;
	int copylen;
	Interface *interface;

	assert(fd > 0);

	if (i >= interface_max_connections ||
	    interfaces[i].fd < 0 || interfaces[i].fd != fd) {
		for (i = 0; i < interface_max_connections; i++) {
			if (interfaces[i].fd == fd)
				break;
		}
		if (i == interface_max_connections)
			return -1;
	}

	/* if fd isn't found or interfaces is going to be closed, do nothing */
	if (interfaces[i].expired)
		return 0;

	interface = interfaces + i;

	while (buflen > 0 && !interface->expired) {
		int left = interface->send_buf_size - interface->send_buf_used;
		copylen = buflen > left ? left : buflen;
		memcpy(interface->send_buf + interface->send_buf_used, buffer,
		       copylen);
		buflen -= copylen;
		interface->send_buf_used += copylen;
		buffer += copylen;
		if (interface->send_buf_used >= interface->send_buf_size)
			printInterfaceOutBuffer(interface);
	}

	return 0;
}

static void printInterfaceOutBuffer(Interface * interface)
{
	int ret;
	struct sllnode *buf;

	if (interface->fd < 0 || interface->expired ||
	    !interface->send_buf_used)
		return;

	if ((buf = interface->deferred_send)) {
		interface->deferred_bytes += sizeof(struct sllnode)
		                             + interface->send_buf_used;
		if (interface->deferred_bytes >
		    interface_max_output_buffer_size) {
			ERROR("interface %i: output buffer size (%li) is "
			      "larger than the max (%li)\n",
			      interface->num,
			      (long)interface->deferred_bytes,
			      (long)interface_max_output_buffer_size);
			/* cause interface to close */
			interface->expired = 1;
			do {
				struct sllnode *prev = buf;
				buf = buf->next;
				free(prev);
			} while (buf);
			interface->deferred_send = NULL;
			interface->deferred_bytes = 0;
		} else {
			while (buf->next)
				buf = buf->next;
			buf->next = new_sllnode(interface->send_buf,
						interface->send_buf_used);
		}
	} else {
		if ((ret = write(interface->fd, interface->send_buf,
				 interface->send_buf_used)) < 0) {
			if (errno == EAGAIN || errno == EINTR) {
				interface->deferred_send =
				    new_sllnode(interface->send_buf,
						interface->send_buf_used);
			} else {
				DEBUG("interface %i: problems writing\n",
				      interface->num);
				interface->expired = 1;
				return;
			}
		} else if (ret < interface->send_buf_used) {
			interface->deferred_send =
			    new_sllnode(interface->send_buf + ret,
					interface->send_buf_used - ret);
		}
		if (interface->deferred_send) {
			DEBUG("interface %i: buffer created\n", interface->num);
			interface->deferred_bytes =
			    interface->deferred_send->size
			    + sizeof(struct sllnode);
		}
	}

	interface->send_buf_used = 0;
}