summaryrefslogtreecommitdiff
path: root/networking/inetd.c
blob: 4440a2d303c352416b6c3a41be6841a0a561e584 (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
/*
 * Copyright (c) 1983,1991 The Regents of the University of California.
 * All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * David A. Holland.
 *
 * Busybox port by Vladimir Oleynik (C) 2001-2003 <dzo@simtreas.ru>
 *
 * 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
 *
 */

/*
 * Inetd - Internet super-server
 *
 * This program invokes all internet services as needed.
 * connection-oriented services are invoked each time a
 * connection is made, by creating a process.  This process
 * is passed the connection as file descriptor 0 and is
 * expected to do a getpeername to find out the source host
 * and port.
 *
 * Datagram oriented services are invoked when a datagram
 * arrives; a process is created and passed a pending message
 * on file descriptor 0.  Datagram servers may either connect
 * to their peer, freeing up the original socket for inetd
 * to receive further messages on, or ``take over the socket'',
 * processing all arriving datagrams and, eventually, timing
 * out.  The first type of server is said to be ``multi-threaded'';
 * the second type of server ``single-threaded''.
 *
 * Inetd uses a configuration file which is read at startup
 * and, possibly, at some later time in response to a hangup signal.
 * The configuration file is ``free format'' with fields given in the
 * order shown below.  Continuation lines for an entry must being with
 * a space or tab.  All fields must be present in each entry.
 *
 *      service name                    must be in /etc/services
 *      socket type                     stream/dgram/raw/rdm/seqpacket
 *      protocol                        must be in /etc/protocols
 *      wait/nowait[.max]               single-threaded/multi-threaded, max #
 *      user[.group]                    user/group to run daemon as
 *      server program                  full path name
 *      server program arguments        maximum of MAXARGS (20)
 *
 * RPC services unsupported
 *
 * Comment lines are indicated by a `#' in column 1.
 */

/*
 * Here's the scoop concerning the user.group feature:
 *
 * 1) No group listed.
 *
 *      a) for root:    NO setuid() or setgid() is done
 *
 *      b) nonroot:     setuid()
 *                      setgid(primary group as found in passwd)
 *                      initgroups(name, primary group)
 *
 * 2) set-group-option on.
 *
 *      a) for root:    NO setuid()
 *                      setgid(specified group)
 *                      setgroups(1, specified group)
 *
 *      b) nonroot:     setuid()
 *                      setgid(specified group)
 *                      initgroups(name, specified group)
 *
 * All supplementary groups are discarded at startup in case inetd was
 * run manually.
 */

#define __USE_BSD_SIGNAL

#include "busybox.h"


#ifndef __linux__
#ifndef RLIMIT_NOFILE
#define RLIMIT_NOFILE   RLIMIT_OFILE
#endif
#endif

#include <sys/file.h>
#include <sys/ioctl.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <sys/un.h>
#include <sys/wait.h>

#include <netinet/in.h>
#include <netinet/ip.h>
#include <arpa/inet.h>

#include <errno.h>
#include <signal.h>
#include <netdb.h>
#include <syslog.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <getopt.h>
#include <unistd.h>
#include <stdarg.h>
#include <time.h>

#ifndef OPEN_MAX
#define OPEN_MAX	64
#endif

#define _PATH_INETDCONF "/etc/inetd.conf"
#define _PATH_INETDPID  "/var/run/inetd.pid"

#define TOOMANY		40		/* don't start more than TOOMANY */
#define CNT_INTVL	60		/* servers in CNT_INTVL sec. */
#define RETRYTIME	(60*10)	/* retry after bind or server fail */
#define MAXARGV		20

#define se_ctrladdr		se_un.se_un_ctrladdr
#define se_ctrladdr_in	se_un.se_un_ctrladdr_in
#define se_ctrladdr_un	se_un.se_un_ctrladdr_un

/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
#define FD_MARGIN	(8)

/* Check unsupporting builtin */
#if defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO || \
	defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD || \
	defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME || \
	defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME || \
	defined CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
# define INETD_FEATURE_ENABLED
#endif

typedef struct servtab_s {
	char    *se_service;            /* name of service */
	int     se_socktype;            /* type of socket to use */
	int     se_family;              /* address family */
	char    *se_proto;              /* protocol used */
	short   se_wait;                /* single threaded server */
	short   se_checked;             /* looked at during merge */
	char    *se_user;               /* user name to run as */
	char    *se_group;              /* group name to run as */
#ifdef INETD_FEATURE_ENABLED
	const struct  biltin *se_bi;    /* if built-in, description */
#endif
	char    *se_server;             /* server program */
	char    *se_argv[MAXARGV+1];    /* program arguments */
	int     se_fd;                  /* open descriptor */
	union {
		struct  sockaddr se_un_ctrladdr;
		struct  sockaddr_in se_un_ctrladdr_in;
		struct  sockaddr_un se_un_ctrladdr_un;
	} se_un;                        /* bound address */
	int     se_ctrladdr_size;
	int     se_max;                 /* max # of instances of this service */
	int     se_count;               /* number started since se_time */
	struct  timeval se_time;        /* start of se_count */
	struct  servtab_s *se_next;
} servtab_t;

static servtab_t *servtab;

#ifdef INETD_FEATURE_ENABLED
struct biltin {
	const char *bi_service;         /* internally provided service name */
	int bi_socktype;                /* type of socket supported */
	short bi_fork;          /* 1 if should fork before call */
	short bi_wait;          /* 1 if should wait for child */
	void (*bi_fn)(int, servtab_t *); /* fn which performs it */
};

    /* Echo received data */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
static void echo_stream(int, servtab_t *);
static void echo_dg(int, servtab_t *);
#endif
    /* Internet /dev/null */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
static void discard_stream(int, servtab_t *);
static void discard_dg(int, servtab_t *);
#endif
	/* Return 32 bit time since 1900 */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
static void machtime_stream(int, servtab_t *);
static void machtime_dg(int, servtab_t *);
#endif
	/* Return human-readable time */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
static void daytime_stream(int, servtab_t *);
static void daytime_dg(int, servtab_t *);
#endif
	/* Familiar character generator */
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
static void chargen_stream(int, servtab_t *);
static void chargen_dg(int, servtab_t *);
#endif

static const struct biltin biltins[] = {
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
	/* Echo received data */
	{ "echo",               SOCK_STREAM,    1, 0,   echo_stream, },
	{ "echo",               SOCK_DGRAM,     0, 0,   echo_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
	/* Internet /dev/null */
	{ "discard",    SOCK_STREAM,    1, 0,   discard_stream, },
	{ "discard",    SOCK_DGRAM,     0, 0,   discard_dg, },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
	/* Return 32 bit time since 1900 */
	{ "time",               SOCK_STREAM,    0, 0,   machtime_stream, },
	{ "time",               SOCK_DGRAM,     0, 0,   machtime_dg,     },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
	/* Return human-readable time */
	{ "daytime",    SOCK_STREAM,    0, 0,   daytime_stream, },
	{ "daytime",    SOCK_DGRAM,     0, 0,   daytime_dg,     },
#endif
#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
	/* Familiar character generator */
	{ "chargen",    SOCK_STREAM,    1, 0,   chargen_stream, },
	{ "chargen",    SOCK_DGRAM,     0, 0,   chargen_dg,     },
#endif
	{ NULL, 0, 0, 0, NULL }
};
#endif  /* INETD_FEATURE_ENABLED */

#ifdef RLIMIT_NOFILE
static struct rlimit   rlim_ofile;
#endif

/* Length of socket listen queue. Should be per-service probably. */
static int      global_queuelen = 128;

static FILE *fconfig;
static sigset_t	blockmask;
static sigset_t	emptymask;
static fd_set	allsock;
static int	nsock;
static int	maxsock;
static int	timingout;
static int	rlim_ofile_cur = OPEN_MAX;
static const char *CONFIG = _PATH_INETDCONF;

static void
syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
	__attribute__ ((noreturn, format (printf, 2, 3)));

static void
syslog_err_and_discard_dg(int se_socktype, const char *msg, ...)
{
	char buf[50];
	va_list p;

	va_start(p, msg);
	vsyslog(LOG_ERR, msg, p);
	if (se_socktype != SOCK_STREAM)
		recv(0, buf, sizeof (buf), 0);
	_exit(1);
}

static char * inetd_strdup(const char *s)
{
	char *ms = strdup(s);

	if(ms == NULL)
		syslog_err_and_discard_dg(SOCK_STREAM, "strdup: %m");
	return ms;
}


static servtab_t *getconfigent(void)
{
	static servtab_t serv;
	servtab_t *sep = &serv;
	int argc;
	char *cp = NULL;
	char *cp_ptr;
	char *cp_ptr_ptr = NULL;

more:
	free(cp);
	cp = bb_get_chomped_line_from_file(fconfig);
	if (feof(fconfig)) {
		free(cp);
		return (NULL);
	}
	if ((cp == NULL) || (*cp == '#')) {
		goto more;
	}
	/* make bind 0.0.0.0 and other zero default */
	memset((char *)sep, 0, sizeof *sep);

	cp_ptr = strtok_r(cp, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* Error */
		goto more;
	}
	sep->se_service = inetd_strdup(cp_ptr);

	cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* Error */
		goto more;
	}
	if (strcmp(cp_ptr, "stream") == 0)
		sep->se_socktype = SOCK_STREAM;
	else if (strcmp(cp_ptr, "dgram") == 0)
		sep->se_socktype = SOCK_DGRAM;
	else if (strcmp(cp_ptr, "rdm") == 0)
		sep->se_socktype = SOCK_RDM;
	else if (strcmp(cp_ptr, "seqpacket") == 0)
		sep->se_socktype = SOCK_SEQPACKET;
	else if (strcmp(cp_ptr, "raw") == 0)
		sep->se_socktype = SOCK_RAW;
	else
		sep->se_socktype = -1;

	cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* error */
		goto more;
	}
	if (strcmp(cp_ptr, "unix") == 0) {
		sep->se_family = AF_UNIX;
	} else {
		if (strncmp(cp_ptr, "rpc/", 4) == 0) {
			syslog(LOG_ERR, "%s: rpc services not supported",
			    sep->se_service);
			goto more;
		}
		sep->se_family = AF_INET;
	}
	sep->se_proto = inetd_strdup(cp_ptr);

	cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* error */
		goto more;
	}
	{
		char *s = strchr(cp_ptr, '.');
		if (s) {
			*s++ = '\0';
			sep->se_max = atoi(s);
		} else
			sep->se_max = TOOMANY;
	}
	sep->se_wait = strcmp(cp_ptr, "wait") == 0;

	cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* error */
		goto more;
	}

	sep->se_user = inetd_strdup(cp_ptr);
	{
		char *cp_ptr2 = strchr(sep->se_user, '.');

		if (cp_ptr2) {
			*cp_ptr2++ = '\0';
		}
		sep->se_group = cp_ptr2;
	}

	cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr);
	if (cp_ptr == NULL) {
		/* error */
		goto more;
	}
	if (strcmp(cp_ptr, "internal") == 0) {
#ifdef INETD_FEATURE_ENABLED
		const struct biltin *bi;

		for (bi = biltins; bi->bi_service; bi++) {
			if ((bi->bi_socktype == sep->se_socktype) &&
			    (strcmp(bi->bi_service, sep->se_service) == 0)) {
				break;
			}
		}
		if (bi->bi_service == 0) {
			syslog(LOG_ERR, "internal service %s unknown", sep->se_service);
			goto more;
		}
		sep->se_bi = bi;
		sep->se_wait = bi->bi_wait;
#else
		syslog(LOG_ERR, "internal service %s unknown", cp_ptr);
		goto more;
#endif
	}
#ifdef INETD_FEATURE_ENABLED
	else {
		sep->se_bi = NULL;
	}
#endif
	sep->se_server = inetd_strdup(cp_ptr);

	argc = 0;
	while ((cp_ptr = strtok_r(NULL, " \t", &cp_ptr_ptr)) != NULL) {
		if (argc < MAXARGV) {
			sep->se_argv[argc++] = inetd_strdup(cp_ptr);
		}
	}
	free(cp);

	return (sep);
}

static void freeconfig(servtab_t *cp)
{
	int i;

	free(cp->se_service);
	free(cp->se_proto);
	free(cp->se_user);
	/* Note: se_group is part of the newstr'ed se_user */
	free(cp->se_server);
	for (i = 0; i < MAXARGV; i++)
		free(cp->se_argv[i]);
}

#ifdef INETD_FEATURE_ENABLED
static char **Argv;
static char *LastArg;

static void setproctitle(char *a, int s)
{
	size_t size;
	char *cp;
	struct sockaddr_in sn;
	char buf[80];

	cp = Argv[0];
	size = sizeof(sn);
	if (getpeername(s, (struct sockaddr *)&sn, &size) == 0)
		(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sn.sin_addr));
	else
		(void) sprintf(buf, "-%s", a);
	strncpy(cp, buf, LastArg - cp);
	cp += strlen(cp);
	while (cp < LastArg)
		*cp++ = ' ';
}
#endif  /* INETD_FEATURE_ENABLED */


static void setup(servtab_t *sep)
{
	int on = 1;

	if ((sep->se_fd = socket(sep->se_family, sep->se_socktype, 0)) < 0) {
		syslog(LOG_ERR, "%s/%s: socket: %m",
		    sep->se_service, sep->se_proto);
		return;
	}
	if (setsockopt(sep->se_fd, SOL_SOCKET, SO_REUSEADDR, (void *)&on,
			    sizeof(on)) < 0)
		syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
	if (bind(sep->se_fd, &sep->se_ctrladdr, sep->se_ctrladdr_size) < 0) {
		syslog(LOG_ERR, "%s/%s: bind: %m",
		    sep->se_service, sep->se_proto);
		(void) close(sep->se_fd);
		sep->se_fd = -1;
		if (!timingout) {
			timingout = 1;
			alarm(RETRYTIME);
		}
		return;
	}
	if (sep->se_socktype == SOCK_STREAM)
		listen(sep->se_fd, global_queuelen);

	FD_SET(sep->se_fd, &allsock);
	nsock++;
	if (sep->se_fd > maxsock) {
		maxsock = sep->se_fd;
		if (maxsock > rlim_ofile_cur - FD_MARGIN) {
#ifdef RLIMIT_NOFILE
# define FD_CHUNK        32
			struct rlimit rl;

			if (getrlimit(RLIMIT_NOFILE, &rl) < 0) {
				syslog(LOG_ERR, "getrlimit: %m");
				return;
			}
			rl.rlim_cur = rl.rlim_max < (rl.rlim_cur + FD_CHUNK) ? rl.rlim_max : (rl.rlim_cur + FD_CHUNK);
			if (rl.rlim_cur <= rlim_ofile_cur) {
				syslog(LOG_ERR,
# if _FILE_OFFSET_BITS == 64
					"bump_nofile: cannot extend file limit, max = %lld",
# else
					"bump_nofile: cannot extend file limit, max = %ld",
# endif
					rl.rlim_cur);
				return;
			}

			if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
				syslog(LOG_ERR, "setrlimit: %m");
				return;
			}

			rlim_ofile_cur = rl.rlim_cur;
			return;
#else
			syslog(LOG_ERR, "bump_nofile: cannot extend file limit");
			return;
#endif	/* RLIMIT_NOFILE */
		}
	}
}

static void config(int signum)
{
	servtab_t *sep, *cp, **sepp;
	sigset_t oldmask;
	unsigned n;

	(void)signum;

	if (fconfig != NULL) {
		fseek(fconfig, 0L, L_SET);
	} else {
		fconfig = fopen(CONFIG, "r");
		if (fconfig == NULL) {
			syslog(LOG_ERR, "%s: %m", CONFIG);
			return;
		}
	}

	for (sep = servtab; sep; sep = sep->se_next)
		sep->se_checked = 0;
	while ((cp = getconfigent()) != NULL) {
		for (sep = servtab; sep; sep = sep->se_next)
			if (strcmp(sep->se_service, cp->se_service) == 0 &&
			    strcmp(sep->se_proto, cp->se_proto) == 0)
				break;
		if (sep != 0) {
			int i;

#define SWAP(type, a, b) {type c=(type)a; (type)a=(type)b; (type)b=(type)c;}

			sigprocmask(SIG_BLOCK, &emptymask, &oldmask);
			/*
			 * sep->se_wait may be holding the pid of a daemon
			 * that we're waiting for.  If so, don't overwrite
			 * it unless the config file explicitly says don't
			 * wait.
			 */
			if (
#ifdef INETD_FEATURE_ENABLED
			    cp->se_bi == 0 &&
#endif
			    (sep->se_wait == 1 || cp->se_wait == 0))
				sep->se_wait = cp->se_wait;
			if (cp->se_max != sep->se_max)
				SWAP(int, cp->se_max, sep->se_max);
			if (cp->se_user)
				SWAP(char *, sep->se_user, cp->se_user);
			if (cp->se_group)
				SWAP(char *, sep->se_group, cp->se_group);
			if (cp->se_server)
				SWAP(char *, sep->se_server, cp->se_server);
			for (i = 0; i < MAXARGV; i++)
				SWAP(char *, sep->se_argv[i], cp->se_argv[i]);
#undef SWAP
			sigprocmask(SIG_SETMASK, &oldmask, NULL);
			// This freeconfig() is probably a bug, since it will try and free()
			// each of the argv[] values, which are really just pointers
			// into the middle of a single line buffer for the config file.
			//freeconfig(cp);	// BUG?
		} else {
			sep = (servtab_t *)xmalloc(sizeof (*sep));
			*sep = *cp;
			sep->se_fd = -1;
			sigprocmask(SIG_BLOCK, &blockmask, &oldmask);
			sep->se_next = servtab;
			servtab = sep;
			sigprocmask(SIG_SETMASK, &oldmask, NULL);
		}
		sep->se_checked = 1;

		switch (sep->se_family) {
		case AF_UNIX:
			if (sep->se_fd != -1)
				break;
			(void)unlink(sep->se_service);
			n = strlen(sep->se_service);
			if (n > sizeof(sep->se_ctrladdr_un.sun_path) - 1)
				n = sizeof(sep->se_ctrladdr_un.sun_path) - 1;
			strncpy(sep->se_ctrladdr_un.sun_path, sep->se_service, n);
			sep->se_ctrladdr_un.sun_family = AF_UNIX;
			sep->se_ctrladdr_size = n +
					sizeof sep->se_ctrladdr_un.sun_family;
			setup(sep);
			break;
		case AF_INET:
			sep->se_ctrladdr_in.sin_family = AF_INET;
			sep->se_ctrladdr_size = sizeof sep->se_ctrladdr_in;
			{
				u_short port = bb_lookup_port(sep->se_service, sep->se_proto, 0);

				if (port == 0) {
					syslog(LOG_ERR,
					    "%s/%s: unknown service",
					    sep->se_service, sep->se_proto);
					continue;
				}
				if (port != sep->se_ctrladdr_in.sin_port) {
					sep->se_ctrladdr_in.sin_port = port;
					if (sep->se_fd != -1) {
						FD_CLR(sep->se_fd, &allsock);
						nsock--;
						(void) close(sep->se_fd);
					}
					sep->se_fd = -1;
				}
				if (sep->se_fd == -1)
					setup(sep);
			}
		}
	}
	if (fconfig) {
		(void) fclose(fconfig);
		fconfig = NULL;
	}
	/*
	 * Purge anything not looked at above.
	 */
	sigprocmask(SIG_SETMASK, &blockmask, &oldmask);
	sepp = &servtab;
	while ((sep = *sepp) != NULL) {
		if (sep->se_checked) {
			sepp = &sep->se_next;
			continue;
		}
		*sepp = sep->se_next;
		if (sep->se_fd != -1) {
			FD_CLR(sep->se_fd, &allsock);
			nsock--;
			(void) close(sep->se_fd);
		}
		if (sep->se_family == AF_UNIX)
			(void)unlink(sep->se_service);
		freeconfig(sep);
		free((char *)sep);
	}
	sigprocmask(SIG_SETMASK, &oldmask, NULL);
}



static void reapchild(int signum)
{
	int status;
	int pid;
	servtab_t *sep;

	(void)signum;
	for (;;) {
		pid = wait3(&status, WNOHANG, (struct rusage *)0);
		if (pid <= 0)
			break;
		for (sep = servtab; sep; sep = sep->se_next)
			if (sep->se_wait == pid) {
				if (WIFEXITED(status) && WEXITSTATUS(status))
					syslog(LOG_WARNING,
					    "%s: exit status 0x%x",
					    sep->se_server, WEXITSTATUS(status));
				else if (WIFSIGNALED(status))
					syslog(LOG_WARNING,
					    "%s: exit signal 0x%x",
					    sep->se_server, WTERMSIG(status));
				sep->se_wait = 1;
				FD_SET(sep->se_fd, &allsock);
				nsock++;
			}
	}
}

static void retry(int signum)
{
	servtab_t *sep;

	(void)signum;
	timingout = 0;
	for (sep = servtab; sep; sep = sep->se_next) {
		if (sep->se_fd == -1) {
			switch (sep->se_family) {
			case AF_UNIX:
			case AF_INET:
				setup(sep);
				break;
			}
		}
	}
}

static void goaway(int signum)
{
	servtab_t *sep;

	(void)signum;
	for (sep = servtab; sep; sep = sep->se_next)
		if (sep->se_fd != -1 && sep->se_family == AF_UNIX)
			(void)unlink(sep->se_service);
	(void)unlink(_PATH_INETDPID);
	exit(0);
}



extern int inetd_main(int argc, char *argv[])
{
	servtab_t *sep;
	struct group *grp = NULL;
	struct sigaction sa;
	int pid;
	unsigned long opt;
	char *sq;
	gid_t gid;

#ifdef INETD_FEATURE_ENABLED
	extern char **environ;
#endif

	gid = getgid();
	setgroups(1, &gid);

#ifdef INETD_FEATURE_ENABLED
	Argv = argv;
	if (environ == 0 || *environ == 0)
		environ = argv;
	while (*environ)
		environ++;
	LastArg = environ[-1] + strlen(environ[-1]);
#endif

#if defined(__uClinux__)
	opt = bb_getopt_ulflags(argc, argv, "q:f", &sq);
	if (!(opt & 2)) {
	    daemon(0, 0);
	    /* reexec for vfork() do continue parent */
	    vfork_daemon_rexec(argc, argv, "-f");
	}
#else
	opt = bb_getopt_ulflags(argc, argv, "q:", &sq);
	daemon(0, 0);
#endif /* uClinux */

	if(opt & 1) {
			global_queuelen = atoi(optarg);
			if (global_queuelen < 8) global_queuelen=8;
		}
	argc -= optind;
	argv += optind;

	if (argc > 0)
		CONFIG = argv[0];

	openlog(bb_applet_name, LOG_PID | LOG_NOWAIT, LOG_DAEMON);
	{
		FILE *fp;

		if ((fp = fopen(_PATH_INETDPID, "w")) != NULL) {
			fprintf(fp, "%u\n", getpid());
			(void)fclose(fp);
		}
	}

#ifdef RLIMIT_NOFILE
	if (getrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
		syslog(LOG_ERR, "getrlimit: %m");
	} else {
		rlim_ofile_cur = rlim_ofile.rlim_cur;
		if (rlim_ofile_cur == RLIM_INFINITY)    /* ! */
			rlim_ofile_cur = OPEN_MAX;
	}
#endif

	config(0);

	sigemptyset(&emptymask);
	sigemptyset(&blockmask);
	sigaddset(&blockmask, SIGCHLD);
	sigaddset(&blockmask, SIGHUP);
	sigaddset(&blockmask, SIGALRM);

	memset(&sa, 0, sizeof(sa));
	sa.sa_mask = blockmask;
	sa.sa_handler = retry;
	sigaction(SIGALRM, &sa, NULL);
	sa.sa_handler = config;
	sigaction(SIGHUP, &sa, NULL);
	sa.sa_handler = reapchild;
	sigaction(SIGCHLD, &sa, NULL);
	sa.sa_handler = goaway;
	sigaction(SIGTERM, &sa, NULL);
	sa.sa_handler = goaway;
	sigaction(SIGINT, &sa,  NULL);
	sa.sa_handler = SIG_IGN;
	sigaction(SIGPIPE, &sa, NULL);

	{
		/* space for daemons to overwrite environment for ps */
#define DUMMYSIZE       100
		char dummy[DUMMYSIZE];

		(void)memset(dummy, 'x', DUMMYSIZE - 1);
		dummy[DUMMYSIZE - 1] = '\0';

		(void)setenv("inetd_dummy", dummy, 1);
	}

	for (;;) {
		fd_set readable;
		int	ctrl;
		int n;

		if (nsock == 0) {
			sigprocmask(SIG_BLOCK, &blockmask, NULL);
			while (nsock == 0) {
				sigsuspend(&emptymask);
			}
			sigprocmask(SIG_SETMASK, &emptymask, NULL);
		}
		readable = allsock;
		n = select(maxsock + 1, &readable, (fd_set *)0, (fd_set *)0, (struct timeval *)0);
		if (n <= 0) {
			if (n < 0 && errno != EINTR) {
				syslog(LOG_WARNING, "select: %m");
			}
			sleep(1);
			continue;
	    }
		for (sep = servtab; n && sep; sep = sep->se_next) {
			if (sep->se_fd != -1 && FD_ISSET(sep->se_fd, &readable)) {
				n--;
				if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
					/* Fixed AGC */
					fcntl(sep->se_fd, F_SETFL, O_NDELAY);
					/* --------- */
					ctrl = accept(sep->se_fd, NULL, NULL);
					fcntl(sep->se_fd, F_SETFL, 0);
					if (ctrl < 0) {
						if (errno == EINTR || errno == EWOULDBLOCK) {
							continue;
						}
						syslog(LOG_WARNING, "accept (for %s): %m",
						sep->se_service);
						continue;
					}
				} else {
					ctrl = sep->se_fd;
				}
				sigprocmask(SIG_BLOCK, &blockmask, NULL);
				pid = 0;
#ifdef INETD_FEATURE_ENABLED
				if (sep->se_bi == 0 || sep->se_bi->bi_fork)
#endif
				{
					if (sep->se_count++ == 0) {
						gettimeofday(&sep->se_time, (struct timezone *)0);
					}
					else if (sep->se_count >= sep->se_max) {
						struct timeval now;

						gettimeofday(&now, (struct timezone *)0);
						if (now.tv_sec - sep->se_time.tv_sec > CNT_INTVL) {
							sep->se_time = now;
							sep->se_count = 1;
						} else {
							syslog(LOG_ERR,
								"%s/%s server failing (looping), service terminated",
								sep->se_service, sep->se_proto);
							FD_CLR(sep->se_fd, &allsock);
							close(sep->se_fd);
							sep->se_fd = -1;
							sep->se_count = 0;
							nsock--;
							sigprocmask(SIG_SETMASK, &emptymask, NULL);
							if (!timingout) {
								timingout = 1;
								alarm(RETRYTIME);
							}
							continue;
						}
					}
					pid = fork();
					if (pid < 0) {
						syslog(LOG_ERR, "fork: %m");
						if (sep->se_socktype == SOCK_STREAM) {
							close(ctrl);
						}
						sigprocmask(SIG_SETMASK, &emptymask, NULL);
						sleep(1);
						continue;
					}
					if (pid && sep->se_wait) {
						sep->se_wait = pid;
						FD_CLR(sep->se_fd, &allsock);
						nsock--;
					}
				}
				sigprocmask(SIG_SETMASK, &emptymask, NULL);
				if (pid == 0) {
#ifdef INETD_FEATURE_ENABLED
					if (sep->se_bi) {
						(*sep->se_bi->bi_fn)(ctrl, sep);
					} else
#endif
					{
						struct passwd *pwd = getpwnam(sep->se_user);
						if (pwd == NULL) {
							syslog_err_and_discard_dg(
								sep->se_socktype,
								"getpwnam: %s: No such user",
								sep->se_user);
						}
						if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
							syslog_err_and_discard_dg(sep->se_socktype,
								"getgrnam: %s: No such group", sep->se_group);
						}
						/*
						 * Ok. There are four cases here:
						 *   1. nonroot user, no group specified
						 *   2. nonroot user, some group specified
						 *   3. root user, no group specified
						 *   4. root user, some group specified
						 * In cases 2 and 4 we setgid to the specified
						 * group. In cases 1 and 2 we run initgroups
						 * to run with the groups of the given user.
						 * In case 4 we do setgroups to run with the
						 * given group. In case 3 we do nothing.
						 */
						if (pwd->pw_uid) {
							if (sep->se_group) {
								pwd->pw_gid = grp->gr_gid;
							}
							setgid((gid_t)pwd->pw_gid);
							initgroups(pwd->pw_name, pwd->pw_gid);
							setuid((uid_t)pwd->pw_uid);
						} else if (sep->se_group) {
							setgid((gid_t)grp->gr_gid);
							setgroups(1, &grp->gr_gid);
						}
						dup2(ctrl, 0);
						close(ctrl);
						dup2(0, 1);
						dup2(0, 2);
#ifdef RLIMIT_NOFILE
						if (rlim_ofile.rlim_cur != rlim_ofile_cur) {
							if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0) {
								syslog(LOG_ERR,"setrlimit: %m");
							}
						}
#endif
						for (ctrl = rlim_ofile_cur-1; --ctrl > 2; ) {
							(void)close(ctrl);
						}
						memset(&sa, 0, sizeof(sa));
						sa.sa_handler = SIG_DFL;
						sigaction(SIGPIPE, &sa, NULL);

						execv(sep->se_server, sep->se_argv);
						syslog_err_and_discard_dg(sep->se_socktype, "execv %s: %m", sep->se_server);
					}
				}
				if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
					close(ctrl);
				}
			}
		}
	}
}


/*
 * Internet services provided internally by inetd:
 */
#define BUFSIZE 4096

#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO
/* Echo service -- echo data back */
static void echo_stream(int s, servtab_t *sep)
{
	char buffer[BUFSIZE];
	int i;

	setproctitle(sep->se_service, s);
	while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
	    write(s, buffer, i) > 0)
		;
	exit(0);
}

/* Echo service -- echo data back */
static void echo_dg(int s, servtab_t *sep)
{
	char buffer[BUFSIZE];
	int i;
	size_t size;
	struct sockaddr sa;

	(void)sep;

	size = sizeof(sa);
	if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
		return;
	(void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_ECHO */


#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD
/* Discard service -- ignore data */
static void discard_stream(int s, servtab_t *sep)
{
	char buffer[BUFSIZE];

	setproctitle(sep->se_service, s);
	while ((errno = 0, read(s, buffer, sizeof(buffer)) > 0) ||
			errno == EINTR)
		;
	exit(0);
}

/* Discard service -- ignore data */
static void discard_dg(int s, servtab_t *sep)
{
	char buffer[BUFSIZE];
	(void)sep;
	read(s, buffer, sizeof(buffer));
}
#endif  /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DISCARD */


#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN
#include <ctype.h>
#define LINESIZ 72
static char ring[128];
static char *endring;

static void initring(void)
{
	int i;

	endring = ring;

	for (i = 0; i <= 128; ++i)
		if (isprint(i))
			*endring++ = i;
}

/* Character generator */
static void chargen_stream(int s, servtab_t *sep)
{
	char *rs;
	int len;
	char text[LINESIZ+2];

	setproctitle(sep->se_service, s);

	if (!endring) {
		initring();
		rs = ring;
	}

	text[LINESIZ] = '\r';
	text[LINESIZ + 1] = '\n';
	for (rs = ring;;) {
		if ((len = endring - rs) >= LINESIZ)
			memcpy(rs, text, LINESIZ);
		else {
			memcpy(rs, text, len);
			memcpy(ring, text + len, LINESIZ - len);
		}
		if (++rs == endring)
			rs = ring;
		if (write(s, text, sizeof(text)) != sizeof(text))
			break;
	}
	exit(0);
}

/* Character generator */
static void chargen_dg(int s, servtab_t *sep)
{
	struct sockaddr sa;
	static char *rs;
	size_t len, size;
	char text[LINESIZ+2];

	(void)sep;

	if (endring == 0) {
		initring();
		rs = ring;
	}

	size = sizeof(sa);
	if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
		return;

	if ((len = endring - rs) >= LINESIZ)
		memcpy(rs, text, LINESIZ);
	else {
		memcpy(rs, text, len);
		memcpy(ring, text + len, LINESIZ - len);
	}
	if (++rs == endring)
		rs = ring;
	text[LINESIZ] = '\r';
	text[LINESIZ + 1] = '\n';
	(void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_CHARGEN */


#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME
/*
 * Return a machine readable date and time, in the form of the
 * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
 * returns the number of seconds since midnight, Jan 1, 1970,
 * we must add 2208988800 seconds to this figure to make up for
 * some seventy years Bell Labs was asleep.
 */

static long machtime(void)
{
	struct timeval tv;

	if (gettimeofday(&tv, (struct timezone *)0) < 0) {
		fprintf(stderr, "Unable to get time of day\n");
		return (0L);
	}
	return (htonl((long)tv.tv_sec + 2208988800UL));
}

static void machtime_stream(int s, servtab_t *sep)
{
	long result;
	(void)sep;

	result = machtime();
	write(s, (char *) &result, sizeof(result));
}

static void machtime_dg(int s, servtab_t *sep)
{
	long result;
	struct sockaddr sa;
	size_t size;
	(void)sep;

	size = sizeof(sa);
	if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
		return;
	result = machtime();
	(void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_TIME */


#ifdef CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME
/* Return human-readable time of day */
static int human_readable_time_sprintf(char *buffer)
{
	time_t clocc = time(NULL);

	return sprintf(buffer, "%.24s\r\n", ctime(&clocc));
}

static void daytime_stream(int s, servtab_t *sep)
{
	char buffer[256];
	size_t st = human_readable_time_sprintf(buffer);

	(void)sep;

	write(s, buffer, st);
}

/* Return human-readable time of day */
static void daytime_dg(int s, servtab_t *sep)
{
	char buffer[256];
	struct sockaddr sa;
	size_t size;

	(void)sep;

	size = sizeof(sa);
	if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
		return;
	size = human_readable_time_sprintf(buffer);
	sendto(s, buffer, size, 0, &sa, sizeof(sa));
}
#endif /* CONFIG_FEATURE_INETD_SUPPORT_BILTIN_DAYTIME */