summaryrefslogtreecommitdiffstats
path: root/main.c
blob: e7292cc8673569914bf89d6606456dfcbb1dfd81 (plain)
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
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
/*
 * usbmuxd -- daemon for communication with iPhone/iPod via USB
 * 
 * Copyright (c) 2009 Nikias Bassen. All Rights Reserved.
 * Based upon iTunnel source code, Copyright (c) 2008 Jing Su.
 *  http://www.cs.toronto.edu/~jingsu/itunnel/
 *
 * 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., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA 
 */
#include <stddef.h>
#include <stdio.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <stdarg.h>
#include <syslog.h>
#include <fcntl.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <sys/stat.h>
#include <arpa/inet.h>
#include <unistd.h>
#include <signal.h>
#include <pthread.h>
#include <stdint.h>
#include <usb.h>
#include <pwd.h>

#include "usbmuxd-proto.h"
#include "sock_stuff.h"

#include "usbmux.h"

#define DEFAULT_TIMEOUT 4000
#define DEFAULT_CHILDREN_CAPACITY 10
#define DEBUG_LEVEL 0

#define LOCKFILE "/var/run/usbmuxd.lock"

#define THREAD (unsigned int)pthread_self()

static int quit_flag = 0;
static int fsock = -1;
static int verbose = DEBUG_LEVEL;
static int foreground = 0;
static int exit_on_no_devices = 0;

struct device_info {
	uint32_t device_id;
	usbmux_device_t phone;
	int use_count;
	pthread_t bulk_reader;
	pthread_mutex_t mutex;
	/* mutex for mutual exclusion of calling the usbmux_send function
	 * TODO: I don't know if we need really need this? */
	pthread_mutex_t writer_mutex;
};

struct client_data {
	volatile int dead;
	int socket;
	int tag;
	pthread_t thread;
	pthread_t handler;
	pthread_t reader;
	int reader_quit;
	int reader_dead;
	int handler_dead;
	int connected;
	usbmux_client_t muxclient;
	struct device_info *dev;
};

static struct device_info **devices = NULL;
static int device_count = 0;
static pthread_mutex_t usbmux_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_mutex_t usb_mutex = PTHREAD_MUTEX_INITIALIZER;

/**
 * logs a message to syslog when running as daemon or to stdout/stderr when
 * running in foreground.
 * @param prio The logging priority.
 * @param format The message to be printed.
 */
static void logmsg(int prio, const char *format, ...)
{
	va_list args;
	va_start(args, format);

	if (!foreground) {
		// daemon. log using syslog.
		vsyslog(prio, format, args);
	} else {
		// running in foreground. log to stdout/stderr.
		char msgbuf[256];
		FILE *lfp = stdout;
		switch (prio) {
		case LOG_EMERG:
		case LOG_ALERT:
		case LOG_CRIT:
		case LOG_ERR:
		case LOG_WARNING:
			lfp = stderr;
			break;
		default:
			lfp = stdout;
		}
		strcpy(msgbuf, "usbmuxd: ");
		vsnprintf(msgbuf + 9, 244, format, args);
		strcat(msgbuf, "\n");
		fputs(msgbuf, lfp);
	}

	va_end(args);
}

#ifdef DEBUG
/**
 * for debugging purposes.
 */
static void print_buffer(FILE * fp, const char *data, const int length)
{
	int i;
	int j;
	unsigned char c;

	for (i = 0; i < length; i += 16) {
		if (verbose >= 4)
			fprintf(fp, "%04x: ", i);
		for (j = 0; j < 16; j++) {
			if (i + j >= length) {
				if (verbose >= 4)
					fprintf(fp, "   ");
				continue;
			}
			if (verbose >= 4)
				fprintf(fp, "%02hhx ", *(data + i + j));
		}
		if (verbose >= 4)
			fprintf(fp, "  | ");
		for (j = 0; j < 16; j++) {
			if (i + j >= length)
				break;
			c = *(data + i + j);
			if ((c < 32) || (c > 127)) {
				if (verbose >= 4)
					fprintf(fp, ".");
				continue;
			}
			if (verbose >= 4)
				fprintf(fp, "%c", c);
		}
		if (verbose >= 4)
			fprintf(fp, "\n");
	}
	if (verbose >= 4)
		fprintf(fp, "\n");
}
#endif

/**
 * Read incoming usbmuxd packet. If the packet is larger than
 * the size specified by len, the data will be truncated.
 *
 * @param fd the file descriptor to read from.
 * @param data pointer to a buffer to store the read data to.
 * @param len the length of the data to be read. The buffer
 *        pointed to by data should be at least len bytes in size.
 *
 * @return 
 */
static int usbmuxd_get_request(int fd, void **data, size_t len)
{
	uint32_t pktlen;
	int recv_len;

	if (peek_buf(fd, &pktlen, sizeof(pktlen)) < (int) sizeof(pktlen)) {
		return -errno;
	}

	if (len == 0) {
		// allocate buffer space
		*data = malloc(pktlen);
	} else if (len < pktlen) {
		// target buffer is to small to hold this packet! fix it!
		if (verbose >= 2)
			logmsg(LOG_WARNING,
				   "%s: WARNING -- packet (%d) is larger than target buffer (%d)! Truncating.",
				   __func__, pktlen, len);
		pktlen = len;
	}

	recv_len = recv_buf(fd, *data, pktlen);
	if ((recv_len > 0) && ((uint32_t) recv_len < pktlen)) {
		if (verbose >= 2)
			logmsg(LOG_WARNING,
				   "%s: Uh-oh, we got less than the packet's size, %d instead of %d...",
				   __func__, recv_len, pktlen);
	}
#ifdef DEBUG
	if (*data && (recv_len > 0) && verbose >= 4) {
		fprintf(stderr, "%s: received:\n", __func__);
		print_buffer(stderr, *data, recv_len);
	}
#endif

	return recv_len;
}

/**
 * Send a usbmuxd result packet with given tag and result_code.
 *
 * @param fd the file descriptor to write to.
 * @param tag the tag value that identifies where this message belongs to.
 * @param result_code the error value (0 = Success, most likely errno values otherwise)
 *
 * @return the return value returned by send_buf (normally the number of bytes sent)
 */
static int usbmuxd_send_result(int fd, uint32_t tag, uint32_t result_code)
{
	struct usbmuxd_result res;
	int ret;

	res.header.length = sizeof(res);
	res.header.reserved = 0;
	res.header.type = USBMUXD_RESULT;
	res.header.tag = tag;
	res.result = result_code;

	if (verbose >= 4)
		logmsg(LOG_NOTICE, "%s: tag=%d result=%d", __func__,
			   res.header.tag, res.result);

	ret = send_buf(fd, &res, sizeof(res));
	fsync(fd);					// let's get it sent
	return ret;
}

/**
 * this thread reads from the usb connection and writes the 
 * data to the connected client.
 *
 * @param arg pointer to a client_data structure.
 *
 * @return NULL in any case
 */
static void *usbmuxd_client_reader_thread(void *arg)
{
	struct client_data *cdata;

	char rbuffer[512];
	uint32_t rbuffersize = 512;
	uint32_t rlen;
	int err;
	char *cursor;
	ssize_t len;
	int result;

	if (!arg) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s: invalid client_data supplied!", __func__);
		cdata->reader_dead = 1;
		return NULL;
	}

	cdata = (struct client_data *) arg;

	cdata->reader_dead = 0;

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%d:%d]: started", __func__,
			   cdata->dev->device_id, cdata->dev->use_count);

	while (!quit_flag && !cdata->reader_quit) {
		result = check_fd(cdata->socket, FD_WRITE, DEFAULT_TIMEOUT);
		if (result <= 0) {
			if (result < 0) {
				if (verbose >= 2)
					logmsg(LOG_ERR, "%s: select error: %s", __func__,
						   strerror(errno));
			}
			continue;
		}

		rlen = 0;
		err =
			usbmux_recv_timeout(cdata->muxclient, rbuffer, rbuffersize,
								&rlen, DEFAULT_TIMEOUT);
		if (err != 0) {
			if (verbose >= 2)
				logmsg(LOG_ERR,
					   "%s[%d:%d]: encountered USB read error: %d",
					   __func__, cdata->dev->device_id,
					   cdata->dev->use_count, err);
			break;
		}

		cursor = rbuffer;
		while (rlen > 0) {
			len = send_buf(cdata->socket, cursor, rlen);
			if (len <= 0) {
				logmsg(LOG_ERR, "%s: Error: send returned %d", __func__,
					   len);
				err = 1;
				break;
			}
			// calculate remainder
			rlen -= len;
			// advance cursor
			cursor += len;
		}
		if (err != 0) {
			logmsg(LOG_ERR, "%s: Error when writing to client...",
				   __func__);
			break;
		}
		fsync(cdata->socket);
	}

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%d:%d]: terminated", __func__,
			   cdata->dev->device_id, cdata->dev->use_count);

	cdata->reader_dead = 1;

	return NULL;
}

/**
 * This function handles the connecting procedure to a previously
 * set up usbmux client.
 * Sends a usbmuxd result packet denoting success or failure.
 * A successful result is mandatory for later communication.
 *
 * @param cdata pointer to a previously initialized client_data structure
 *
 * @return
 */
static int usbmuxd_handleConnectResult(struct client_data *cdata)
{
	int result;
	char buffer[512];
	char err_type[64];
	int err_code;
	ssize_t maxlen = 512;
	uint32_t rlen;
	int err;

	if (!cdata) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s: Invalid client_data provided!", __func__);
		return -EINVAL;
	}

	result = check_fd(cdata->socket, FD_WRITE, DEFAULT_TIMEOUT);
	if (result <= 0) {
		if (result < 0) {
			if (verbose >= 2)
				logmsg(LOG_ERR, "%s: select error: %s", __func__,
					   strerror(errno));
			return result;
		}
	} else {
		result = 0;
		err =
			usbmux_recv_timeout(cdata->muxclient, buffer, maxlen, &rlen,
								100);
		if (err < 0) {
			if (verbose >= 2)
				logmsg(LOG_ERR, "%s: encountered USB read error: %d",
					   __func__, err);
			usbmuxd_send_result(cdata->socket, cdata->tag, -err);
			return err;
		} else {
			if (rlen > 0) {
				if ((buffer[0] == 1) && (rlen > 20)
					&& !memcmp(buffer + 1, "handleConnectResult:", 20)) {
					// hm... we got an error message!
					buffer[rlen] = 0;
					if (verbose >= 1)
						logmsg(LOG_ERR, "%s: %s\n", __func__, buffer + 22);

					if (sscanf
						(buffer + 22, "%s - %d\n", err_type, &err_code)
						== 2) {
						usbmuxd_send_result(cdata->socket, cdata->tag,
											err_code);
						return -err_code;
					} else {
						usbmuxd_send_result(cdata->socket, cdata->tag,
											ENODATA);
						return -ENODATA;
					}
				} else {
					// send success result
					usbmuxd_send_result(cdata->socket, cdata->tag, 0);
					// and the server greeting message
					send_buf(cdata->socket, buffer, rlen);
				}
			} else {
				// no server greeting? this seems to be ok. send success.
				usbmuxd_send_result(cdata->socket, cdata->tag, 0);
			}
		}
		//fsync(cdata->socket);
	}
	return result;
}

/**
 * This thread handles the communication between the connected iPhone/iPod
 * and the client that created the connection.
 */
static void *usbmuxd_client_handler_thread(void *arg)
{
	struct client_data *cdata;
	int result;
	char *cursor;
	char buffer[65536];
	ssize_t len;
	ssize_t maxlen = sizeof(buffer);
	uint32_t wlen;
	int err;

	if (!arg) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s: invalid client_data provided!", __func__);
		return NULL;
	}

	cdata = (struct client_data *) arg;

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%d:%d]: started", __func__,
			   cdata->dev->device_id, cdata->dev->use_count);

	if (usbmuxd_handleConnectResult(cdata)) {
		if (verbose >= 3)
			logmsg(LOG_ERR, "handleConnectResult: Error");
		goto leave;
	} else {
		if (verbose >= 3)
			logmsg(LOG_NOTICE, "handleConnectResult: Success");
	}

	// starting mux reader thread
	cdata->reader_quit = 0;
	cdata->reader_dead = 0;
	if (pthread_create
		(&cdata->reader, NULL, usbmuxd_client_reader_thread, cdata) != 0) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s: could not start client_reader thread",
				   __func__);
		cdata->reader = 0;
	}

	while (!quit_flag && !cdata->reader_dead) {
		result = check_fd(cdata->socket, FD_READ, DEFAULT_TIMEOUT);
		if (result <= 0) {
			if (result < 0) {
				if (verbose >= 3)
					logmsg(LOG_ERR, "%s: Error: checkfd: %s", __func__,
						   strerror(errno));
			}
			continue;
		}
		// check_fd told us there's data available, so read from client
		// and push to USB device.
		len = recv(cdata->socket, buffer, maxlen, 0);
		if (len == 0) {
			break;
		}
		if (len < 0) {
			if (verbose >= 2)
				logmsg(LOG_ERR, "%s[%d:%d]: Error: recv: %s", __func__,
					   cdata->dev->device_id, cdata->dev->use_count,
					   strerror(errno));
			break;
		}

		cursor = buffer;

		pthread_mutex_lock(&cdata->dev->writer_mutex);
		do {
			wlen = 0;
			err = usbmux_send(cdata->muxclient, cursor, len, &wlen);
			if (err == -ETIMEDOUT) {
				// some kind of timeout... just be patient and retry.
			} else if (err < 0) {
				if (verbose >= 2)
					logmsg(LOG_ERR, "%s[%d:%d]: USB write error: %d",
						   __func__, cdata->dev->device_id,
						   cdata->dev->use_count, err);
				len = -1;
				break;
			}
			// calculate remainder.
			len -= wlen;
			// advance cursor appropiately.
			cursor += wlen;
		}
		while ((len > 0) && !quit_flag);
		pthread_mutex_unlock(&cdata->dev->writer_mutex);
		if (len < 0) {
			break;
		}
	}

  leave:
	// cleanup
	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%d:%d]: terminating", __func__,
			   cdata->dev->device_id, cdata->dev->use_count);
	if (cdata->reader != 0) {
		cdata->reader_quit = 1;
		pthread_join(cdata->reader, NULL);
	}

	cdata->handler_dead = 1;

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%d:%d]: terminated", __func__,
			   cdata->dev->device_id, cdata->dev->use_count);
	return NULL;
}

/**
 * Thread performing usb_bulk_read from the connected device.
 * One thread per device. Lives as long as the device is in use.
 */
static void *usbmuxd_bulk_reader_thread(void *arg)
{
	struct device_info *cur_dev;
	int err;

	if (!arg) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s: Invalid client_data provided", __func__);
		return NULL;
	}

	cur_dev = (struct device_info *) arg;

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s: started", __func__);

	while (!quit_flag && cur_dev) {

		pthread_mutex_lock(&cur_dev->mutex);
		if (cur_dev->use_count <= 0) {
			pthread_mutex_unlock(&cur_dev->mutex);
			break;
		}
		pthread_mutex_unlock(&cur_dev->mutex);

		if ((err = usbmux_pullbulk(cur_dev->phone)) < 0) {
			if (verbose >= 1)
				logmsg(LOG_ERR, "%s: error %d when reading from device",
					   __func__, err);
			break;
		}
	}

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s: terminated", __func__);

	return NULL;
}

/**
 * This thread is started when a new connection is accepted.
 * It performs the handshake, then waits for the connect packet and
 * on success it starts the usbmuxd_client_handler thread.
 */
static void *usbmuxd_client_init_thread(void *arg)
{
	struct client_data *cdata;
	struct usbmuxd_scan_request *s_req = NULL;
	struct usbmuxd_device_info_record dev_info_rec;
	struct usbmuxd_connect_request *c_req = NULL;

	struct usb_bus *bus;
	struct usb_device *dev;

	int recv_len;
	int found = 0;
	int res;
	int i;

	usbmux_device_t phone = NULL;
	struct device_info *cur_dev = NULL;

	if (!arg) {
		if (verbose >= 1)
			logmsg(LOG_ERR, "%s[%x]: invalid client_data provided!",
				   __func__, THREAD);
		return NULL;
	}

	cdata = (struct client_data *) arg;
	cdata->dead = 0;

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%x]: started (fd=%d)", __func__, THREAD,
			   cdata->socket);

	if ((recv_len =
		 usbmuxd_get_request(cdata->socket, (void **) &s_req, 0)) <= 0) {
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s[%x]: No scan packet received, error %s",
				   __func__, THREAD, strerror(errno));
		goto leave;
	}

	if ((recv_len == sizeof(struct usbmuxd_scan_request))
		&& (s_req->header.length == sizeof(struct usbmuxd_scan_request))
		&& (s_req->header.reserved == 0)
		&& (s_req->header.type == USBMUXD_SCAN)) {
		// send success response
		if (verbose >= 3)
			logmsg(LOG_NOTICE, "%s[%x]: Got scan packet!", __func__,
				   THREAD);
		usbmuxd_send_result(cdata->socket, s_req->header.tag, 0);
	} else if ((recv_len == sizeof(struct usbmuxd_connect_request))
			   && (s_req->header.type == USBMUXD_CONNECT)) {
		c_req = (struct usbmuxd_connect_request *) s_req;
		s_req = NULL;
		goto connect;
	} else {
		// send error response and exit
		if (verbose >= 2)
			logmsg(LOG_ERR, "%s[%x]: Invalid scan packet received.",
				   __func__, THREAD);
		// TODO is this required?!
		usbmuxd_send_result(cdata->socket, s_req->header.tag, EINVAL);
		goto leave;
	}

	pthread_mutex_lock(&usb_mutex);
	// gather data about all iPhones/iPods attached

	if (verbose >= 5)
		logmsg(LOG_DEBUG, "%s[%x]: usb init", __func__, THREAD);
	usb_init();
	if (verbose >= 5)
		logmsg(LOG_DEBUG, "%s[%x]: usb find busses", __func__, THREAD);
	usb_find_busses();
	if (verbose >= 5)
		logmsg(LOG_DEBUG, "%s[%x]: usb find devices", __func__, THREAD);
	usb_find_devices();

	if (verbose >= 2)
		logmsg(LOG_NOTICE, "%s[%x]: Looking for attached devices...",
			   __func__, THREAD);

	for (bus = usb_get_busses(); bus; bus = bus->next) {
		for (dev = bus->devices; dev; dev = dev->next) {
			if (dev->descriptor.idVendor == 0x05ac
				&& dev->descriptor.idProduct >= 0x1290
				&& dev->descriptor.idProduct <= 0x1293) {
				if (verbose >= 1)
					logmsg(LOG_NOTICE,
						   "%s[%x]: Found device on bus %d, id %d",
						   __func__, THREAD, bus->location, dev->devnum);
				found++;

				// construct packet
				memset(&dev_info_rec, 0, sizeof(dev_info_rec));
				dev_info_rec.header.length = sizeof(dev_info_rec);
				dev_info_rec.header.type = USBMUXD_DEVICE_INFO;
				dev_info_rec.device.device_id = dev->devnum;
				dev_info_rec.device.product_id = dev->descriptor.idProduct;
				if (dev->descriptor.iSerialNumber) {
					usb_dev_handle *udev;
					//pthread_mutex_lock(&usbmux_mutex);
					udev = usb_open(dev);
					if (udev) {
						usb_get_string_simple(udev,
											  dev->descriptor.
											  iSerialNumber,
											  dev_info_rec.device.
											  serial_number,
											  sizeof(dev_info_rec.device.
													 serial_number) + 1);
						usb_close(udev);
					}
					//pthread_mutex_unlock(&usbmux_mutex);
				}
#ifdef DEBUG
				if (verbose >= 4)
					print_buffer(stderr, (char *) &dev_info_rec,
								 sizeof(dev_info_rec));
#endif

				// send it
				if (send_buf
					(cdata->socket, &dev_info_rec,
					 sizeof(dev_info_rec)) <= 0) {
					if (verbose >= 3)
						logmsg(LOG_ERR,
							   "%s[%x]: Error: Could not send device info: %s",
							   __func__, THREAD, strerror(errno));
					found--;
				}
			}
		}
	}
	pthread_mutex_unlock(&usb_mutex);

	if (found <= 0) {
		if (verbose >= 1)
			logmsg(LOG_NOTICE,
				   "%s[%x]: No attached iPhone/iPod devices found.",
				   __func__, THREAD);
		goto leave;
	}

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%x]: Waiting for connect request", __func__,
			   THREAD);

	// now wait for connect request
	//memset(&c_req, 0, sizeof(c_req));
	if ((recv_len =
		 usbmuxd_get_request(cdata->socket, (void **) &c_req, 0)) <= 0) {
		if (verbose >= 3)
			logmsg(LOG_NOTICE,
				   "%s[%x]: Did not receive any connect request.",
				   __func__, THREAD);
		goto leave;
	}

  connect:

	if (c_req->header.type != USBMUXD_CONNECT) {
		if (verbose >= 2)
			logmsg(LOG_ERR,
				   "%s[%x]: Unexpected packet of type %d received.",
				   __func__, THREAD, c_req->header.type);
		goto leave;
	}

	if (verbose >= 3)
		logmsg(LOG_NOTICE,
			   "%s[%x]: Setting up connection to usb device #%d on port %d",
			   __func__, THREAD, c_req->device_id,
			   ntohs(c_req->tcp_dport));

	// find the device, and open usb connection
	pthread_mutex_lock(&usbmux_mutex);
	phone = NULL;
	cur_dev = NULL;
	// first check if we already have an open connection
	if (devices) {
		for (i = 0; i < device_count; i++) {
			if (devices[i]) {
				if (devices[i]->device_id == c_req->device_id) {
					devices[i]->use_count++;
					cur_dev = devices[i];
					phone = cur_dev->phone;
					break;
				}
			}
		}
	}
	if (!phone) {
		// if not found, make a new connection
		if (verbose >= 2)
			logmsg(LOG_NOTICE,
				   "%s[%x]: creating new usb connection, device_id=%d",
				   __func__, THREAD, c_req->device_id);

		pthread_mutex_lock(&usb_mutex);
		if (usbmux_get_specific_device(0, c_req->device_id, &phone) < 0) {
			pthread_mutex_unlock(&usb_mutex);
			pthread_mutex_unlock(&usbmux_mutex);
			if (verbose >= 1)
				logmsg(LOG_ERR, "%s[%x]: device_id %d could not be opened",
					   __func__, THREAD, c_req->device_id);
			usbmuxd_send_result(cdata->socket, c_req->header.tag, ENODEV);
			goto leave;
		}
		pthread_mutex_unlock(&usb_mutex);

		// create device object
		if (verbose >= 3)
			logmsg(LOG_DEBUG, "%s[%x]: add to device list", __func__,
				   THREAD);
		cur_dev =
			(struct device_info *) malloc(sizeof(struct device_info));
		memset(cur_dev, 0, sizeof(struct device_info));
		cur_dev->use_count = 1;
		cur_dev->device_id = c_req->device_id;
		cur_dev->phone = phone;
		cur_dev->bulk_reader = 0;
		pthread_mutex_init(&cur_dev->mutex, NULL);
		pthread_mutex_init(&cur_dev->writer_mutex, NULL);

		if (verbose >= 3)
			logmsg(LOG_DEBUG, "%s[%x]: device_count = %d", __func__,
				   THREAD, device_count);

		// add to list of devices
		devices =
			(struct device_info **) realloc(devices,
											sizeof(struct device_info *) *
											(device_count + 1));
		if (devices) {
			devices[device_count] = cur_dev;
			device_count++;
		}
	} else {
		if (verbose >= 2)
			logmsg(LOG_NOTICE,
				   "%s[%x]: reusing usb connection, device_id=%d",
				   __func__, THREAD, c_req->device_id);
	}
	pthread_mutex_unlock(&usbmux_mutex);

	// setup connection to iPhone/iPod
//    pthread_mutex_lock(&usbmux_mutex);
	res =
		usbmux_new_client(cur_dev->phone, 0, ntohs(c_req->tcp_dport),
						  &(cdata->muxclient));
//    pthread_mutex_unlock(&usbmux_mutex);

	if (res != 0) {
		usbmuxd_send_result(cdata->socket, c_req->header.tag, res);
		if (verbose >= 1)
			logmsg(LOG_ERR,
				   "%s[%x]: mux_new_client returned %d, aborting.",
				   __func__, THREAD, res);
		goto leave;
	}
	// start bulk reader thread (once per device)
	pthread_mutex_lock(&cur_dev->mutex);
	if (cur_dev->bulk_reader == 0) {
		pthread_create(&cur_dev->bulk_reader, NULL,
					   usbmuxd_bulk_reader_thread, cur_dev);
	}
	pthread_mutex_unlock(&cur_dev->mutex);

	// start connection handler thread
	cdata->handler_dead = 0;
	cdata->tag = c_req->header.tag;
	cdata->dev = cur_dev;
	if (pthread_create
		(&cdata->handler, NULL, usbmuxd_client_handler_thread, cdata) != 0)
	{
		if (verbose >= 1)
			logmsg(LOG_ERR,
				   "%s[%x]: could not create usbmuxd_client_handler_thread!",
				   __func__, THREAD);
		cdata->handler = 0;
		goto leave;
	}
	// wait for handler thread to finish its work
	if (cdata->handler != 0) {
		pthread_join(cdata->handler, NULL);
	}

	if (verbose >= 2)
		logmsg(LOG_NOTICE, "%s[%x]: closing connection", __func__, THREAD);

	// time to clean up
	if (cdata && cdata->muxclient) {	// should be non-NULL
		usbmux_free_client(cdata->muxclient);
	}

  leave:
	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%x]: terminating", __func__, THREAD);

	if (s_req) {
		free(s_req);
	}
	if (c_req) {
		free(c_req);
	}
	// this has to be freed only if it's not in use anymore as it closes
	// the USB connection
	pthread_mutex_lock(&usbmux_mutex);
	if (cur_dev) {
		pthread_mutex_lock(&cur_dev->mutex);
		if (cur_dev->use_count > 1) {
			if (verbose >= 2)
				logmsg(LOG_NOTICE,
					   "%s[%x]: decreasing device use count (from %d to %d)",
					   __func__, THREAD, cur_dev->use_count,
					   cur_dev->use_count - 1);
			cur_dev->use_count--;
			pthread_mutex_unlock(&cur_dev->mutex);
		} else {
			if (verbose >= 2)
				logmsg(LOG_NOTICE,
					   "%s[%x]: last client disconnected, cleaning up",
					   __func__, THREAD);
			cur_dev->use_count = 0;
			pthread_mutex_unlock(&cur_dev->mutex);
			if (cur_dev->bulk_reader != 0) {
				if (verbose >= 3)
					logmsg(LOG_NOTICE, "%s[%x]: joining bulk_reader...",
						   __func__, THREAD);
				pthread_join(cur_dev->bulk_reader, NULL);
			}
			pthread_mutex_lock(&usb_mutex);
			usbmux_free_device(cur_dev->phone);
			pthread_mutex_unlock(&usb_mutex);
			pthread_mutex_destroy(&cur_dev->writer_mutex);
			pthread_mutex_destroy(&cur_dev->mutex);
			free(cur_dev);
			cur_dev = NULL;
			if (device_count > 1) {
				struct device_info **newlist;
				int j;

				newlist =
					(struct device_info **)
					malloc(sizeof(struct device_info *)
						   * device_count - 1);
				for (i = 0; i < device_count; i++) {
					if (devices[i] != NULL) {
						newlist[j++] = devices[i];
					}
				}
				free(devices);
				devices = newlist;
				device_count--;
			} else {
				free(devices);
				devices = NULL;
				device_count = 0;
			}
		}
	}
	pthread_mutex_unlock(&usbmux_mutex);

	cdata->dead = 1;
	close(cdata->socket);

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "%s[%x]: terminated", __func__, THREAD);

	return NULL;
}

/**
 * make this program run detached from the current console
 */
static int daemonize()
{
	pid_t pid;
	pid_t sid;

	// already a daemon
	if (getppid() == 1)
		return 0;

	pid = fork();
	if (pid < 0) {
		exit(EXIT_FAILURE);
	}

	if (pid > 0) {
		// exit parent process
		exit(EXIT_SUCCESS);
	}
	// At this point we are executing as the child process

	// Change the file mode mask
	umask(0);

	// Create a new SID for the child process
	sid = setsid();
	if (sid < 0) {
		return -1;
	}
	// Change the current working directory.
	if ((chdir("/")) < 0) {
		return -2;
	}
	// Redirect standard files to /dev/null
	freopen("/dev/null", "r", stdin);
	freopen("/dev/null", "w", stdout);
	freopen("/dev/null", "w", stderr);

	return 0;
}

/**
 * signal handler function for cleaning up properly
 */
static void clean_exit(int sig)
{
	if (sig == SIGINT) {
		if (verbose >= 1)
			fprintf(stderr, "CTRL+C pressed\n");
	}
	quit_flag = 1;
}

static void usage()
{
	printf("usage: usbmuxd [options]\n");
	printf("\t-h|--help        print this message.\n");
	printf("\t-v|--verbose     be verbose\n");
	printf("\t-f|--foreground  do not daemonize\n");
	printf("\n");
}

static void parse_opts(int argc, char **argv)
{
	static struct option longopts[] = {
		{"help", 0, NULL, 'h'},
		{"foreground", 0, NULL, 'f'},
		{"verbose", 0, NULL, 'v'},
		{"exit-on-no-devices", 0, NULL, 'e'},
		{NULL, 0, NULL, 0}
	};
	int c;

	while (1) {
		c = getopt_long(argc, argv, "hfve", longopts, (int *) 0);
		if (c == -1) {
			break;
		}

		switch (c) {
		case 'h':
			usage();
			exit(0);
		case 'f':
			foreground = 1;
			break;
		case 'v':
			sock_stuff_set_verbose(++verbose);
			break;
		case 'e':
			exit_on_no_devices = 1;
			break;
		default:
			usage();
			exit(2);
		}
	}
}

/**
 * checks for attached devices
 *
 * @return number of devices found
 */
static int devices_attached()
{
	struct usb_bus *bus;
	struct usb_device *dev;
	int res = 0;

	usb_init();
	usb_find_busses();
	usb_find_devices();

	for (bus = usb_get_busses(); bus; bus = bus->next) {
		for (dev = bus->devices; dev; dev = dev->next) {
			if (dev->descriptor.idVendor == 0x05ac
				&& dev->descriptor.idProduct >= 0x1290
				&& dev->descriptor.idProduct <= 0x1293) {
				res++;
			}
		}
	}

	return res;
}

/**
 * main function. Initializes all stuff and then loops waiting in accept.
 */
int main(int argc, char **argv)
{
	struct sockaddr_un c_addr;
	socklen_t len = sizeof(struct sockaddr_un);
	struct client_data *cdata = NULL;
	struct client_data **children = NULL;
	int children_capacity = DEFAULT_CHILDREN_CAPACITY;
	int i;
	int result = 0;
	int cnt = 0;
	FILE *lfd = NULL;
	struct flock lock;

	parse_opts(argc, argv);

	argc -= optind;
	argv += optind;

	if (!foreground) {
		openlog("usbmuxd", LOG_PID, 0);
	}

	if (verbose >= 2)
		logmsg(LOG_NOTICE, "starting");

	// signal(SIGHUP, reload_conf); // none yet
	signal(SIGINT, clean_exit);
	signal(SIGQUIT, clean_exit);
	signal(SIGTERM, clean_exit);
	signal(SIGPIPE, SIG_IGN);

	// check for other running instance
	lfd = fopen(LOCKFILE, "r");
	if (lfd) {
		lock.l_type = 0;
		lock.l_whence = SEEK_SET;
		lock.l_start = 0;
		lock.l_len = 0;
		fcntl(fileno(lfd), F_GETLK, &lock);
		fclose(lfd);
		if (lock.l_type != F_UNLCK) {
			logmsg(LOG_NOTICE,
				   "another instance is already running. exiting.");
			return -1;
		}
	}

	if (exit_on_no_devices) {
		if (devices_attached() <= 0) {
			logmsg(LOG_NOTICE, "no devices attached. exiting.");
			return 0;
		}
	}

	fsock = create_unix_socket(USBMUXD_SOCKET_FILE);
	if (fsock < 0) {
		logmsg(LOG_ERR, "Could not create socket, exiting");
		if (!foreground) {
			closelog();
		}
		return -1;
	}

	chmod(USBMUXD_SOCKET_FILE, 0666);

	if (verbose >= 3)
		usbmux_set_debug(1);

	if (!foreground) {
		if (daemonize() < 0) {
			fprintf(stderr, "usbmuxd: FATAL: Could not daemonize!\n");
			syslog(LOG_ERR, "FATAL: Could not daemonize!");
			closelog();
			exit(EXIT_FAILURE);
		}
	}
	// now open the lockfile and place the lock
	lfd = fopen(LOCKFILE, "w");
	if (lfd) {
		lock.l_type = F_WRLCK;
		lock.l_whence = SEEK_SET;
		lock.l_start = 0;
		lock.l_len = 0;
		if (fcntl(fileno(lfd), F_SETLK, &lock) == -1) {
			logmsg(LOG_ERR, "ERROR: lockfile locking failed!");
		}
	}
	// drop elevated privileges
	if (getuid() == 0 || geteuid() == 0) {
		struct passwd *pw = getpwnam("nobody");
		if (pw) {
			setuid(pw->pw_uid);
		} else {
			logmsg(LOG_ERR,
				   "ERROR: Dropping privileges failed, check if user 'nobody' exists! Will now terminate.");
			exit(EXIT_FAILURE);
		}

		// security check
		if (setuid(0) != -1) {
			logmsg(LOG_ERR, "ERROR: Failed to drop privileges properly!");
			exit(EXIT_FAILURE);
		}
		if (verbose >= 2)
			logmsg(LOG_NOTICE, "Successfully dropped privileges");
	}
	// Reserve space for 10 clients which should be enough. If not, the
	// buffer gets enlarged later.
	children =
		(struct client_data **) malloc(sizeof(struct client_data *) *
									   children_capacity);
	if (!children) {
		logmsg(LOG_ERR,
			   "Out of memory when allocating memory for child threads. Terminating.");
		if (!foreground) {
			closelog();
		}
		exit(EXIT_FAILURE);
	}
	memset(children, 0, sizeof(struct client_data *) * children_capacity);

	if (verbose >= 2)
		logmsg(LOG_NOTICE, "waiting for connection");
	while (!quit_flag) {
		// Check the file descriptor before accepting a connection.
		// If no connection attempt is made, just repeat...
		result = check_fd(fsock, FD_READ, 1000);
		if (result <= 0) {
			if (result == 0) {
				// cleanup
				for (i = 0; i < children_capacity; i++) {
					if (children[i]) {
						if (children[i]->dead != 0) {
							pthread_join(children[i]->thread, NULL);
							if (verbose >= 3)
								logmsg(LOG_NOTICE,
									   "reclaimed client thread (fd=%d)",
									   children[i]->socket);
							free(children[i]);
							children[i] = NULL;
							cnt++;
						} else {
							cnt = 0;
						}
					} else {
						cnt++;
					}
				}

				if ((children_capacity > DEFAULT_CHILDREN_CAPACITY)
					&& ((children_capacity - cnt) <=
						DEFAULT_CHILDREN_CAPACITY)) {
					children_capacity = DEFAULT_CHILDREN_CAPACITY;
					children =
						realloc(children,
								sizeof(struct client_data *) *
								children_capacity);
				}
				continue;
			} else {
				if (verbose >= 3)
					logmsg(LOG_ERR, "usbmuxd: select error: %s",
						   strerror(errno));
				continue;
			}
		}

		cdata = (struct client_data *) malloc(sizeof(struct client_data));
		memset(cdata, 0, sizeof(struct client_data));
		if (!cdata) {
			quit_flag = 1;
			logmsg(LOG_ERR, "Error: Out of memory! Terminating.");
			break;
		}

		cdata->socket = accept(fsock, (struct sockaddr *) &c_addr, &len);
		if (cdata->socket < 0) {
			free(cdata);
			if (errno == EINTR) {
				continue;
			} else {
				if (verbose >= 3)
					logmsg(LOG_ERR, "Error in accept: %s",
						   strerror(errno));
				continue;
			}
		}

		if (verbose >= 1)
			logmsg(LOG_NOTICE, "new client connected (fd=%d)",
				   cdata->socket);

		// create client thread:
		if (pthread_create
			(&cdata->thread, NULL, usbmuxd_client_init_thread, cdata) == 0)
		{
			for (i = 0; i < children_capacity; i++) {
				if (children[i] == NULL)
					break;
			}
			if (i == children_capacity) {
				// enlarge buffer
				children_capacity++;
				children =
					realloc(children,
							sizeof(struct client_data *) *
							children_capacity);
				if (!children) {
					logmsg(LOG_ERR,
						   "Out of memory when enlarging child thread buffer");
				}
			}
			children[i] = cdata;
		} else {
			logmsg(LOG_ERR, "Failed to create client_init_thread.");
			close(cdata->socket);
			free(cdata);
			cdata = NULL;
		}
	}

	if (verbose >= 3)
		logmsg(LOG_NOTICE, "terminating");

	// preparing for shutdown: wait for child threads to terminate (if any)
	if (verbose >= 2)
		logmsg(LOG_NOTICE, "waiting for child threads to terminate...");
	for (i = 0; i < children_capacity; i++) {
		if (children[i] != NULL) {
			pthread_join(children[i]->thread, NULL);
			free(children[i]);
		}
	}

	// delete the children set.
	free(children);
	children = NULL;


	if (fsock >= 0) {
		close(fsock);
	}

	unlink(USBMUXD_SOCKET_FILE);

	// unlock lock file and close it.
	if (lfd) {
		lock.l_type = F_UNLCK;
		fcntl(fileno(lfd), F_SETLK, &lock);
		fclose(lfd);
	}

	if (verbose >= 1)
		logmsg(LOG_NOTICE, "usbmuxd: terminated");
	if (!foreground) {
		closelog();
	}

	return 0;
}