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
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
|
/* vi: set sw=4 ts=4: */
/* $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $ */
/* $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $ */
/* $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $ */
/* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru> */
/* IPv6 support, many bug fixes by Denys Vlasenko (c) 2008 */
/*
* Copyright (c) 1983,1991 The Regents of the University of California.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/* Inetd - Internet super-server
*
* This program invokes configured services when a connection
* from a peer is established or a datagram arrives.
* 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 peer's 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. peer's address can be obtained
* using recvfrom.
*
* 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 begin 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
* (usually "tcp" or "udp")
* wait/nowait[.max] single-threaded/multi-threaded, max #
* user[.group] or user[:group] user/group to run daemon as
* server_program full path name
* server_program_arguments maximum of MAXARGS (20)
*
* For RPC services
* service_name/version must be in /etc/rpc
* socket_type stream/dgram/raw/rdm/seqpacket
* rpc/protocol "rpc/tcp" etc
* wait/nowait[.max] single-threaded/multi-threaded
* user[.group] or user[:group] user to run daemon as
* server_program full path name
* server_program_arguments maximum of MAXARGS (20)
*
* For non-RPC services, the "service name" can be of the form
* hostaddress:servicename, in which case the hostaddress is used
* as the host portion of the address to listen on. If hostaddress
* consists of a single '*' character, INADDR_ANY is used.
*
* A line can also consist of just
* hostaddress:
* where hostaddress is as in the preceding paragraph. Such a line must
* have no further fields; the specified hostaddress is remembered and
* used for all further lines that have no hostaddress specified,
* until the next such line (or EOF). (This is why * is provided to
* allow explicit specification of INADDR_ANY.) A line
* *:
* is implicitly in effect at the beginning of the file.
*
* The hostaddress specifier may (and often will) contain dots;
* the service name must not.
*
* For RPC services, host-address specifiers are accepted and will
* work to some extent; however, because of limitations in the
* portmapper interface, it will not work to try to give more than
* one line for any given RPC service, even if the host-address
* specifiers are different.
*
* Comment lines are indicated by a '#' in column 1.
*/
/* inetd rules for passing file descriptors to children
* (http://www.freebsd.org/cgi/man.cgi?query=inetd):
*
* The wait/nowait entry specifies whether the server that is invoked by
* inetd will take over the socket associated with the service access point,
* and thus whether inetd should wait for the server to exit before listen-
* ing for new service requests. Datagram servers must use "wait", as
* they are always invoked with the original datagram socket bound to the
* specified service address. These servers must read at least one datagram
* from the socket before exiting. If a datagram server connects to its
* peer, freeing the socket so inetd can receive further messages on the
* socket, it is said to be a "multi-threaded" server; it should read one
* datagram from the socket and create a new socket connected to the peer.
* It should fork, and the parent should then exit to allow inetd to check
* for new service requests to spawn new servers. Datagram servers which
* process all incoming datagrams on a socket and eventually time out are
* said to be "single-threaded". The comsat(8), biff(1) and talkd(8)
* utilities are both examples of the latter type of datagram server. The
* tftpd(8) utility is an example of a multi-threaded datagram server.
*
* Servers using stream sockets generally are multi-threaded and use the
* "nowait" entry. Connection requests for these services are accepted by
* inetd, and the server is given only the newly-accepted socket connected
* to a client of the service. Most stream-based services operate in this
* manner. Stream-based servers that use "wait" are started with the lis-
* tening service socket, and must accept at least one connection request
* before exiting. Such a server would normally accept and process incoming
* connection requests until a timeout.
*/
/* Despite of above doc saying that dgram services must use "wait",
* "udp nowait" servers are implemented in busyboxed inetd.
* IPv6 addresses are also implemented. However, they may look ugly -
* ":::service..." means "address '::' (IPv6 wildcard addr)":"service"...
* You have to put "tcp6"/"udp6" in protocol field to select IPv6.
*/
/* Here's the scoop concerning the user[:group] feature:
* 1) group is not specified:
* a) user = root: NO setuid() or setgid() is done
* b) other: initgroups(name, primary group)
* setgid(primary group as found in passwd)
* setuid()
* 2) group is specified:
* a) user = root: setgid(specified group)
* NO initgroups()
* NO setuid()
* b) other: initgroups(name, specified group)
* setgid(specified group)
* setuid()
*/
//config:config INETD
//config: bool "inetd (18 kb)"
//config: default y
//config: select FEATURE_SYSLOG
//config: help
//config: Internet superserver daemon
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_ECHO
//config: bool "Support echo service on port 7"
//config: default y
//config: depends on INETD
//config: help
//config: Internal service which echoes data back.
//config: Activated by configuration lines like these:
//config: echo stream tcp nowait root internal
//config: echo dgram udp wait root internal
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
//config: bool "Support discard service on port 8"
//config: default y
//config: depends on INETD
//config: help
//config: Internal service which discards all input.
//config: Activated by configuration lines like these:
//config: discard stream tcp nowait root internal
//config: discard dgram udp wait root internal
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_TIME
//config: bool "Support time service on port 37"
//config: default y
//config: depends on INETD
//config: help
//config: Internal service which returns big-endian 32-bit number
//config: of seconds passed since 1900-01-01. The number wraps around
//config: on overflow.
//config: Activated by configuration lines like these:
//config: time stream tcp nowait root internal
//config: time dgram udp wait root internal
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
//config: bool "Support daytime service on port 13"
//config: default y
//config: depends on INETD
//config: help
//config: Internal service which returns human-readable time.
//config: Activated by configuration lines like these:
//config: daytime stream tcp nowait root internal
//config: daytime dgram udp wait root internal
//config:
//config:config FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
//config: bool "Support chargen service on port 19"
//config: default y
//config: depends on INETD
//config: help
//config: Internal service which generates endless stream
//config: of all ASCII chars beetween space and char 126.
//config: Activated by configuration lines like these:
//config: chargen stream tcp nowait root internal
//config: chargen dgram udp wait root internal
//config:
//config:config FEATURE_INETD_RPC
//config: bool "Support RPC services"
//config: default n # very rarely used, and needs Sun RPC support in libc
//config: depends on INETD
//config: help
//config: Support Sun-RPC based services
//applet:IF_INETD(APPLET(inetd, BB_DIR_USR_SBIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_INETD) += inetd.o
//usage:#define inetd_trivial_usage
//usage: "[-fe] [-q N] [-R N] [CONFFILE]"
//usage:#define inetd_full_usage "\n\n"
//usage: "Listen for network connections and launch programs\n"
//usage: "\n -f Run in foreground"
//usage: "\n -e Log to stderr"
//usage: "\n -q N Socket listen queue (default 128)"
//usage: "\n -R N Pause services after N connects/min"
//usage: "\n (default 0 - disabled)"
//usage: "\n Default CONFFILE is /etc/inetd.conf"
#include <syslog.h>
#include <sys/resource.h> /* setrlimit */
#include <sys/socket.h> /* un.h may need this */
#include <sys/un.h>
#include "libbb.h"
#include "common_bufsiz.h"
#if ENABLE_FEATURE_INETD_RPC
# if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
# warning "You probably need to build uClibc with UCLIBC_HAS_RPC for NFS support"
/* not #error, since user may be using e.g. libtirpc instead.
* This might work:
* CONFIG_EXTRA_CFLAGS="-I/usr/include/tirpc"
* CONFIG_EXTRA_LDLIBS="tirpc"
*/
# endif
# include <rpc/rpc.h>
# include <rpc/pmap_clnt.h>
#endif
#if !BB_MMU
/* stream version of chargen is forking but not execing,
* can't do that (easily) on NOMMU */
#undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
#endif
#define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
#define RETRYTIME 60 /* retry after bind or server fail */
// TODO: explain, or get rid of setrlimit games
#ifndef RLIMIT_NOFILE
#define RLIMIT_NOFILE RLIMIT_OFILE
#endif
#ifndef OPEN_MAX
#define OPEN_MAX 64
#endif
/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
#define FD_MARGIN 8
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
# define INETD_BUILTINS_ENABLED
#endif
typedef struct servtab_t {
/* The most frequently referenced one: */
int se_fd; /* open descriptor */
/* NB: 'biggest fields last' saves on code size (~250 bytes) */
/* [addr:]service socktype proto wait user[:group] prog [args] */
char *se_local_hostname; /* addr to listen on */
char *se_service; /* "80" or "www" or "mount/2[-3]" */
/* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
#if ENABLE_FEATURE_INETD_RPC
int se_rpcprog; /* rpc program number */
int se_rpcver_lo; /* rpc program lowest version */
int se_rpcver_hi; /* rpc program highest version */
#define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
#else
#define is_rpc_service(sep) 0
#endif
pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
/* and waiting for this pid */
socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
family_t se_family; /* AF_UNIX/INET[6] */
/* se_proto_no is used by RPC code only... hmm */
smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
smallint se_checked; /* looked at during merge */
unsigned se_max; /* allowed instances per minute */
unsigned se_count; /* number started since se_time */
unsigned se_time; /* when we started counting */
char *se_user; /* user name to run as */
char *se_group; /* group name to run as, can be NULL */
#ifdef INETD_BUILTINS_ENABLED
const struct builtin *se_builtin; /* if built-in, description */
#endif
struct servtab_t *se_next;
len_and_sockaddr *se_lsa;
char *se_program; /* server program */
#define MAXARGV 20
char *se_argv[MAXARGV + 1]; /* program arguments */
} servtab_t;
#ifdef INETD_BUILTINS_ENABLED
/* Echo received data */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
static void FAST_FUNC echo_stream(int, servtab_t *);
static void FAST_FUNC echo_dg(int, servtab_t *);
#endif
/* Internet /dev/null */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
static void FAST_FUNC discard_stream(int, servtab_t *);
static void FAST_FUNC discard_dg(int, servtab_t *);
#endif
/* Return 32 bit time since 1900 */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
static void FAST_FUNC machtime_stream(int, servtab_t *);
static void FAST_FUNC machtime_dg(int, servtab_t *);
#endif
/* Return human-readable time */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
static void FAST_FUNC daytime_stream(int, servtab_t *);
static void FAST_FUNC daytime_dg(int, servtab_t *);
#endif
/* Familiar character generator */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
static void FAST_FUNC chargen_stream(int, servtab_t *);
static void FAST_FUNC chargen_dg(int, servtab_t *);
#endif
struct builtin {
/* NB: not necessarily NUL terminated */
char bi_service7[7]; /* internally provided service name */
uint8_t bi_fork; /* 1 if stream fn should run in child */
void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
};
static const struct builtin builtins[] ALIGN_PTR = {
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
{ "echo", 1, echo_stream, echo_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
{ "discard", 1, discard_stream, discard_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
{ "chargen", 1, chargen_stream, chargen_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
{ "time", 0, machtime_stream, machtime_dg },
#endif
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
{ "daytime", 0, daytime_stream, daytime_dg },
#endif
};
#endif /* INETD_BUILTINS_ENABLED */
struct globals {
rlim_t rlim_ofile_cur;
struct rlimit rlim_ofile;
servtab_t *serv_list;
int global_queuelen;
int maxsock; /* max fd# in allsock, -1: unknown */
/* whenever maxsock grows, prev_maxsock is set to new maxsock,
* but if maxsock is set to -1, prev_maxsock is not changed */
int prev_maxsock;
unsigned max_concurrency;
smallint alarm_armed;
uid_t real_uid; /* user ID who ran us */
const char *config_filename;
parser_t *parser;
char *default_local_hostname;
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
char *end_ring;
char *ring_pos;
char ring[128];
#endif
fd_set allsock;
/* Used in next_line(), and as scratch read buffer */
char line[256]; /* _at least_ 256, see LINE_SIZE */
} FIX_ALIASING;
#define G (*(struct globals*)bb_common_bufsiz1)
enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
#define rlim_ofile_cur (G.rlim_ofile_cur )
#define rlim_ofile (G.rlim_ofile )
#define serv_list (G.serv_list )
#define global_queuelen (G.global_queuelen)
#define maxsock (G.maxsock )
#define prev_maxsock (G.prev_maxsock )
#define max_concurrency (G.max_concurrency)
#define alarm_armed (G.alarm_armed )
#define real_uid (G.real_uid )
#define config_filename (G.config_filename)
#define parser (G.parser )
#define default_local_hostname (G.default_local_hostname)
#define first_ps_byte (G.first_ps_byte )
#define last_ps_byte (G.last_ps_byte )
#define end_ring (G.end_ring )
#define ring_pos (G.ring_pos )
#define ring (G.ring )
#define allsock (G.allsock )
#define line (G.line )
#define INIT_G() do { \
setup_common_bufsiz(); \
BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
rlim_ofile_cur = OPEN_MAX; \
global_queuelen = 128; \
config_filename = "/etc/inetd.conf"; \
} while (0)
#if 1
# define dbg(...) ((void)0)
#else
# define dbg(...) \
do { \
int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
if (dbg_fd >= 0) { \
fdprintf(dbg_fd, "%d: ", getpid()); \
fdprintf(dbg_fd, __VA_ARGS__); \
close(dbg_fd); \
} \
} while (0)
#endif
static void maybe_close(int fd)
{
if (fd >= 0) {
close(fd);
dbg("closed fd:%d\n", fd);
}
}
// TODO: move to libbb?
static len_and_sockaddr *xzalloc_lsa(int family)
{
len_and_sockaddr *lsa;
int sz;
sz = sizeof(struct sockaddr_in);
if (family == AF_UNIX)
sz = sizeof(struct sockaddr_un);
#if ENABLE_FEATURE_IPV6
if (family == AF_INET6)
sz = sizeof(struct sockaddr_in6);
#endif
lsa = xzalloc(LSA_LEN_SIZE + sz);
lsa->len = sz;
lsa->u.sa.sa_family = family;
return lsa;
}
static void rearm_alarm(void)
{
if (!alarm_armed) {
alarm_armed = 1;
alarm(RETRYTIME);
}
}
static void block_CHLD_HUP_ALRM(sigset_t *m)
{
sigemptyset(m);
sigaddset(m, SIGCHLD);
sigaddset(m, SIGHUP);
sigaddset(m, SIGALRM);
sigprocmask2(SIG_BLOCK, m); /* old sigmask is stored in m */
}
static void restore_sigmask(sigset_t *m)
{
sigprocmask(SIG_SETMASK, m, NULL);
}
#if ENABLE_FEATURE_INETD_RPC
static void register_rpc(servtab_t *sep)
{
int n;
struct sockaddr_in ir_sin;
if (bb_getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, sizeof(ir_sin)) < 0) {
//TODO: verify that such failure is even possible in Linux kernel
bb_simple_perror_msg("getsockname");
return;
}
for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
pmap_unset(sep->se_rpcprog, n);
if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
sep->se_service, sep->se_proto,
sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
}
}
static void unregister_rpc(servtab_t *sep)
{
int n;
for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
if (!pmap_unset(sep->se_rpcprog, n))
bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
}
}
#endif /* FEATURE_INETD_RPC */
static void bump_nofile(void)
{
enum { FD_CHUNK = 32 };
struct rlimit rl;
/* Never fails under Linux (except if you pass it bad arguments) */
getrlimit(RLIMIT_NOFILE, &rl);
rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
if (rl.rlim_cur <= rlim_ofile_cur) {
bb_error_msg("can't extend file limit, max = %d",
(int) rl.rlim_cur);
return;
}
if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
bb_simple_perror_msg("setrlimit");
return;
}
rlim_ofile_cur = rl.rlim_cur;
}
static void remove_fd_from_set(int fd)
{
if (fd >= 0) {
FD_CLR(fd, &allsock);
dbg("stopped listening on fd:%d\n", fd);
maxsock = -1;
dbg("maxsock:%d\n", maxsock);
}
}
static void add_fd_to_set(int fd)
{
if (fd >= 0) {
FD_SET(fd, &allsock);
dbg("started listening on fd:%d\n", fd);
if (maxsock >= 0 && fd > maxsock) {
prev_maxsock = maxsock = fd;
dbg("maxsock:%d\n", maxsock);
if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
bump_nofile();
}
}
}
static void recalculate_maxsock(void)
{
int fd = 0;
/* We may have no services, in this case maxsock should still be >= 0
* (code elsewhere is not happy with maxsock == -1) */
maxsock = 0;
while (fd <= prev_maxsock) {
if (FD_ISSET(fd, &allsock))
maxsock = fd;
fd++;
}
dbg("recalculated maxsock:%d\n", maxsock);
prev_maxsock = maxsock;
if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
bump_nofile();
}
static void prepare_socket_fd(servtab_t *sep)
{
int r, fd;
fd = socket(sep->se_family, sep->se_socktype, 0);
if (fd < 0) {
bb_simple_perror_msg("socket");
return;
}
setsockopt_reuseaddr(fd);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep)) {
struct passwd *pwd;
/* zero out the port for all RPC services; let bind()
* find one. */
set_nport(&sep->se_lsa->u.sa, 0);
/* for RPC services, attempt to use a reserved port
* if they are going to be running as root. */
if (real_uid == 0 && sep->se_family == AF_INET
&& (pwd = getpwnam(sep->se_user)) != NULL
&& pwd->pw_uid == 0
) {
r = bindresvport(fd, &sep->se_lsa->u.sin);
} else {
r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
}
if (r == 0) {
int saveerrno = errno;
/* update lsa with port# */
getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
errno = saveerrno;
}
} else
#endif
{
if (sep->se_family == AF_UNIX) {
struct sockaddr_un *sun;
sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
unlink(sun->sun_path);
}
r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
}
if (r < 0) {
bb_perror_msg("%s/%s: bind",
sep->se_service, sep->se_proto);
close(fd);
rearm_alarm();
return;
}
if (sep->se_socktype == SOCK_STREAM) {
listen(fd, global_queuelen);
dbg("new sep->se_fd:%d (stream)\n", fd);
} else {
dbg("new sep->se_fd:%d (!stream)\n", fd);
}
add_fd_to_set(fd);
sep->se_fd = fd;
}
static int reopen_config_file(void)
{
free(default_local_hostname);
default_local_hostname = xstrdup("*");
if (parser != NULL)
config_close(parser);
parser = config_open(config_filename);
return (parser != NULL);
}
static void close_config_file(void)
{
if (parser) {
config_close(parser);
parser = NULL;
}
}
static void free_servtab_strings(servtab_t *cp)
{
int i;
free(cp->se_local_hostname);
free(cp->se_service);
free(cp->se_proto);
free(cp->se_user);
free(cp->se_group);
free(cp->se_lsa); /* not a string in fact */
free(cp->se_program);
for (i = 0; i < MAXARGV; i++)
free(cp->se_argv[i]);
}
static servtab_t *new_servtab(void)
{
servtab_t *newtab = xzalloc(sizeof(servtab_t));
newtab->se_fd = -1; /* paranoia */
return newtab;
}
static servtab_t *dup_servtab(servtab_t *sep)
{
servtab_t *newtab;
int argc;
newtab = new_servtab();
*newtab = *sep; /* struct copy */
/* deep-copying strings */
newtab->se_service = xstrdup(newtab->se_service);
newtab->se_proto = xstrdup(newtab->se_proto);
newtab->se_user = xstrdup(newtab->se_user);
newtab->se_group = xstrdup(newtab->se_group);
newtab->se_program = xstrdup(newtab->se_program);
for (argc = 0; argc <= MAXARGV; argc++)
newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
/* NB: se_fd, se_hostaddr and se_next are always
* overwrittend by callers, so we don't bother resetting them
* to NULL/0/-1 etc */
return newtab;
}
/* gcc generates much more code if this is inlined */
static NOINLINE servtab_t *parse_one_line(void)
{
int argc;
char *token[6+MAXARGV];
char *p, *arg;
char *hostdelim;
servtab_t *sep;
servtab_t *nsep;
new:
sep = new_servtab();
more:
argc = config_read(parser, token, 6+MAXARGV, 1, "# \t", PARSE_NORMAL);
if (!argc) {
free(sep);
return NULL;
}
/* [host:]service socktype proto wait user[:group] prog [args] */
/* Check for "host:...." line */
arg = token[0];
hostdelim = strrchr(arg, ':');
if (hostdelim) {
*hostdelim = '\0';
sep->se_local_hostname = xstrdup(arg);
arg = hostdelim + 1;
if (*arg == '\0' && argc == 1) {
/* Line has just "host:", change the
* default host for the following lines. */
free(default_local_hostname);
default_local_hostname = sep->se_local_hostname;
/*sep->se_local_hostname = NULL; - redundant */
/* (we'll overwrite this field anyway) */
goto more;
}
} else
sep->se_local_hostname = xstrdup(default_local_hostname);
/* service socktype proto wait user[:group] prog [args] */
sep->se_service = xstrdup(arg);
/* socktype proto wait user[:group] prog [args] */
if (argc < 6) {
parse_err:
bb_error_msg("parse error on line %u, line is ignored",
parser->lineno);
/* Just "goto more" can make sep to carry over e.g.
* "rpc"-ness (by having se_rpcver_lo != 0).
* We will be more paranoid: */
free_servtab_strings(sep);
free(sep);
goto new;
}
{
static const int8_t SOCK_xxx[] ALIGN1 = {
-1,
SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
SOCK_SEQPACKET, SOCK_RAW
};
sep->se_socktype = SOCK_xxx[1 + index_in_strings(
"stream""\0" "dgram""\0" "rdm""\0"
"seqpacket""\0" "raw""\0"
, token[1])];
}
/* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
sep->se_proto = arg = xstrdup(token[2]);
if (strcmp(arg, "unix") == 0) {
sep->se_family = AF_UNIX;
} else {
char *six;
sep->se_family = AF_INET;
six = last_char_is(arg, '6');
if (six) {
#if ENABLE_FEATURE_IPV6
*six = '\0';
sep->se_family = AF_INET6;
#else
bb_error_msg("%s: no support for IPv6", sep->se_proto);
goto parse_err;
#endif
}
if (is_prefixed_with(arg, "rpc/")) {
#if ENABLE_FEATURE_INETD_RPC
unsigned n;
arg += 4;
p = strchr(sep->se_service, '/');
if (p == NULL) {
bb_error_msg("no rpc version: '%s'", sep->se_service);
goto parse_err;
}
*p++ = '\0';
n = bb_strtou(p, &p, 10);
if (n > INT_MAX) {
bad_ver_spec:
bb_simple_error_msg("bad rpc version");
goto parse_err;
}
sep->se_rpcver_lo = sep->se_rpcver_hi = n;
if (*p == '-') {
p++;
n = bb_strtou(p, &p, 10);
if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
goto bad_ver_spec;
sep->se_rpcver_hi = n;
}
if (*p != '\0')
goto bad_ver_spec;
#else
bb_simple_error_msg("no support for rpc services");
goto parse_err;
#endif
}
/* we don't really need getprotobyname()! */
if (strcmp(arg, "tcp") == 0)
sep->se_proto_no = IPPROTO_TCP; /* = 6 */
if (strcmp(arg, "udp") == 0)
sep->se_proto_no = IPPROTO_UDP; /* = 17 */
if (six)
*six = '6';
if (!sep->se_proto_no) /* not tcp/udp?? */
goto parse_err;
}
/* [no]wait[.max] user[:group] prog [args] */
arg = token[3];
sep->se_max = max_concurrency;
p = strchr(arg, '.');
if (p) {
*p++ = '\0';
sep->se_max = bb_strtou(p, NULL, 10);
if (errno)
goto parse_err;
}
sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
if (!sep->se_wait) /* "no" seen */
arg += 2;
if (strcmp(arg, "wait") != 0)
goto parse_err;
/* user[:group] prog [args] */
sep->se_user = xstrdup(token[4]);
arg = strchr(sep->se_user, '.');
if (arg == NULL)
arg = strchr(sep->se_user, ':');
if (arg) {
*arg++ = '\0';
sep->se_group = xstrdup(arg);
}
/* prog [args] */
sep->se_program = xstrdup(token[5]);
#ifdef INETD_BUILTINS_ENABLED
if (strcmp(sep->se_program, "internal") == 0
&& strlen(sep->se_service) <= 7
&& (sep->se_socktype == SOCK_STREAM
|| sep->se_socktype == SOCK_DGRAM)
) {
unsigned i;
for (i = 0; i < ARRAY_SIZE(builtins); i++)
if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
goto found_bi;
bb_error_msg("unknown internal service %s", sep->se_service);
goto parse_err;
found_bi:
sep->se_builtin = &builtins[i];
/* stream builtins must be "nowait", dgram must be "wait" */
if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
goto parse_err;
}
#endif
argc = 0;
while (argc < MAXARGV && (arg = token[6+argc]) != NULL)
sep->se_argv[argc++] = xstrdup(arg);
/* Some inetd.conf files have no argv's, not even argv[0].
* Fix them up.
* (Technically, programs can be execed with argv[0] = NULL,
* but many programs do not like that at all) */
if (argc == 0)
sep->se_argv[0] = xstrdup(sep->se_program);
/* catch mixups. "<service> stream udp ..." == wtf */
if (sep->se_socktype == SOCK_STREAM) {
if (sep->se_proto_no == IPPROTO_UDP)
goto parse_err;
}
if (sep->se_socktype == SOCK_DGRAM) {
if (sep->se_proto_no == IPPROTO_TCP)
goto parse_err;
}
//bb_error_msg(
// "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
// sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
// sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
/* check if the hostname specifier is a comma separated list
* of hostnames. we'll make new entries for each address. */
while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
nsep = dup_servtab(sep);
/* NUL terminate the hostname field of the existing entry,
* and make a dup for the new entry. */
*hostdelim++ = '\0';
nsep->se_local_hostname = xstrdup(hostdelim);
nsep->se_next = sep->se_next;
sep->se_next = nsep;
}
/* was doing it here: */
/* DNS resolution, create copies for each IP address */
/* IPv6-ization destroyed it :( */
return sep;
}
static servtab_t *insert_in_servlist(servtab_t *cp)
{
servtab_t *sep;
sigset_t omask;
sep = new_servtab();
*sep = *cp; /* struct copy */
sep->se_fd = -1;
#if ENABLE_FEATURE_INETD_RPC
sep->se_rpcprog = -1;
#endif
block_CHLD_HUP_ALRM(&omask);
sep->se_next = serv_list;
serv_list = sep;
restore_sigmask(&omask);
return sep;
}
static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
{
if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
return 0;
if (strcmp(old->se_service, new->se_service) != 0)
return 0;
if (strcmp(old->se_proto, new->se_proto) != 0)
return 0;
return 1;
}
static void reread_config_file(int sig UNUSED_PARAM)
{
servtab_t *sep, *cp, **sepp;
len_and_sockaddr *lsa;
sigset_t omask;
unsigned n;
uint16_t port;
int save_errno = errno;
if (!reopen_config_file())
goto ret;
for (sep = serv_list; sep; sep = sep->se_next)
sep->se_checked = 0;
goto first_line;
while (1) {
if (cp == NULL) {
first_line:
cp = parse_one_line();
if (cp == NULL)
break;
}
for (sep = serv_list; sep; sep = sep->se_next)
if (same_serv_addr_proto(sep, cp))
goto equal_servtab;
/* not an "equal" servtab */
sep = insert_in_servlist(cp);
goto after_check;
equal_servtab:
{
int i;
block_CHLD_HUP_ALRM(&omask);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep))
unregister_rpc(sep);
sep->se_rpcver_lo = cp->se_rpcver_lo;
sep->se_rpcver_hi = cp->se_rpcver_hi;
#endif
if (cp->se_wait == 0) {
/* New config says "nowait". If old one
* was "wait", we currently may be waiting
* for a child (and not accepting connects).
* Stop waiting, start listening again.
* (if it's not true, this op is harmless) */
add_fd_to_set(sep->se_fd);
}
sep->se_wait = cp->se_wait;
sep->se_max = cp->se_max;
/* string fields need more love - we don't want to leak them */
#define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
SWAP(char*, sep->se_user, cp->se_user);
SWAP(char*, sep->se_group, cp->se_group);
SWAP(char*, sep->se_program, cp->se_program);
for (i = 0; i < MAXARGV; i++)
SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
#undef SWAP
restore_sigmask(&omask);
free_servtab_strings(cp);
}
after_check:
/* cp->string_fields are consumed by insert_in_servlist()
* or freed at this point, cp itself is not yet freed. */
sep->se_checked = 1;
/* create new len_and_sockaddr */
switch (sep->se_family) {
struct sockaddr_un *sun;
case AF_UNIX:
lsa = xzalloc_lsa(AF_UNIX);
sun = (struct sockaddr_un*)&lsa->u.sa;
safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
break;
default: /* case AF_INET, case AF_INET6 */
n = bb_strtou(sep->se_service, NULL, 10);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep)) {
sep->se_rpcprog = n;
if (errno) { /* se_service is not numeric */
struct rpcent *rp = getrpcbyname(sep->se_service);
if (rp == NULL) {
bb_error_msg("%s: unknown rpc service", sep->se_service);
goto next_cp;
}
sep->se_rpcprog = rp->r_number;
}
if (sep->se_fd == -1)
prepare_socket_fd(sep);
if (sep->se_fd != -1)
register_rpc(sep);
goto next_cp;
}
#endif
/* what port to listen on? */
port = htons(n);
if (errno || n > 0xffff) { /* se_service is not numeric */
char protoname[4];
struct servent *sp;
/* can result only in "tcp" or "udp": */
safe_strncpy(protoname, sep->se_proto, 4);
sp = getservbyname(sep->se_service, protoname);
if (sp == NULL) {
bb_error_msg("%s/%s: unknown service",
sep->se_service, sep->se_proto);
goto next_cp;
}
port = sp->s_port;
}
if (LONE_CHAR(sep->se_local_hostname, '*')) {
lsa = xzalloc_lsa(sep->se_family);
set_nport(&lsa->u.sa, port);
} else {
lsa = host_and_af2sockaddr(sep->se_local_hostname,
ntohs(port), sep->se_family);
if (!lsa) {
bb_error_msg("%s/%s: unknown host '%s'",
sep->se_service, sep->se_proto,
sep->se_local_hostname);
goto next_cp;
}
}
break;
} /* end of "switch (sep->se_family)" */
/* did lsa change? Then close/open */
if (sep->se_lsa == NULL
|| lsa->len != sep->se_lsa->len
|| memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
) {
remove_fd_from_set(sep->se_fd);
maybe_close(sep->se_fd);
free(sep->se_lsa);
sep->se_lsa = lsa;
sep->se_fd = -1;
} else {
free(lsa);
}
if (sep->se_fd == -1)
prepare_socket_fd(sep);
next_cp:
sep = cp->se_next;
free(cp);
cp = sep;
} /* end of "while (1) parse lines" */
close_config_file();
/* Purge anything not looked at above - these are stale entries,
* new config file doesnt have them. */
block_CHLD_HUP_ALRM(&omask);
sepp = &serv_list;
while ((sep = *sepp) != NULL) {
if (sep->se_checked) {
sepp = &sep->se_next;
continue;
}
*sepp = sep->se_next;
remove_fd_from_set(sep->se_fd);
maybe_close(sep->se_fd);
#if ENABLE_FEATURE_INETD_RPC
if (is_rpc_service(sep))
unregister_rpc(sep);
#endif
if (sep->se_family == AF_UNIX)
unlink(sep->se_service);
free_servtab_strings(sep);
free(sep);
}
restore_sigmask(&omask);
ret:
errno = save_errno;
}
static void reap_child(int sig UNUSED_PARAM)
{
pid_t pid;
int status;
servtab_t *sep;
int save_errno = errno;
for (;;) {
pid = wait_any_nohang(&status);
if (pid <= 0)
break;
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_wait != pid)
continue;
/* One of our "wait" services */
if (WIFEXITED(status) && WEXITSTATUS(status))
bb_error_msg("%s: exit status %u",
sep->se_program, WEXITSTATUS(status));
else if (WIFSIGNALED(status))
bb_error_msg("%s: exit signal %u",
sep->se_program, WTERMSIG(status));
sep->se_wait = 1;
add_fd_to_set(sep->se_fd);
break;
}
}
errno = save_errno;
}
static void retry_network_setup(int sig UNUSED_PARAM)
{
int save_errno = errno;
servtab_t *sep;
alarm_armed = 0;
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_fd == -1) {
prepare_socket_fd(sep);
#if ENABLE_FEATURE_INETD_RPC
if (sep->se_fd != -1 && is_rpc_service(sep))
register_rpc(sep);
#endif
}
}
errno = save_errno;
}
static void clean_up_and_exit(int sig UNUSED_PARAM)
{
servtab_t *sep;
/* XXX signal race walking sep list */
for (sep = serv_list; sep; sep = sep->se_next) {
if (sep->se_fd == -1)
continue;
switch (sep->se_family) {
case AF_UNIX:
unlink(sep->se_service);
break;
default: /* case AF_INET, AF_INET6 */
#if ENABLE_FEATURE_INETD_RPC
if (sep->se_wait == 1 && is_rpc_service(sep))
unregister_rpc(sep); /* XXX signal race */
#endif
break;
}
if (ENABLE_FEATURE_CLEAN_UP)
close(sep->se_fd);
}
remove_pidfile_std_path_and_ext("inetd");
exit_SUCCESS();
}
int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int inetd_main(int argc UNUSED_PARAM, char **argv)
{
struct sigaction sa, saved_pipe_handler;
servtab_t *sep, *sep2;
struct passwd *pwd;
struct group *grp = grp; /* for compiler */
int opt;
pid_t pid;
sigset_t omask;
INIT_G();
real_uid = getuid();
if (real_uid != 0) /* run by non-root user */
config_filename = NULL;
/* -q N, -R N */
opt = getopt32(argv, "R:+feq:+", &max_concurrency, &global_queuelen);
argv += optind;
//argc -= optind;
if (argv[0])
config_filename = argv[0];
if (config_filename == NULL)
bb_simple_error_msg_and_die("non-root must specify config file");
if (!(opt & 2))
bb_daemonize_or_rexec(0, argv - optind);
else
bb_sanitize_stdio();
if (!(opt & 4)) {
/* LOG_NDELAY: connect to syslog daemon NOW.
* Otherwise, we may open syslog socket
* in vforked child, making opened fds and syslog()
* internal state inconsistent.
* This was observed to leak file descriptors. */
openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
logmode = LOGMODE_SYSLOG;
}
if (real_uid == 0) {
/* run by root, ensure groups vector gets trashed */
gid_t gid = getgid();
setgroups(1, &gid);
}
write_pidfile_std_path_and_ext("inetd");
/* never fails under Linux (except if you pass it bad arguments) */
getrlimit(RLIMIT_NOFILE, &rlim_ofile);
rlim_ofile_cur = rlim_ofile.rlim_cur;
if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
rlim_ofile_cur = OPEN_MAX;
memset(&sa, 0, sizeof(sa));
/*sigemptyset(&sa.sa_mask); - memset did it */
sigaddset(&sa.sa_mask, SIGALRM);
sigaddset(&sa.sa_mask, SIGCHLD);
sigaddset(&sa.sa_mask, SIGHUP);
//FIXME: explain why no SA_RESTART
//FIXME: retry_network_setup is unsafe to run in signal handler (many reasons)!
sa.sa_handler = retry_network_setup;
sigaction_set(SIGALRM, &sa);
//FIXME: reread_config_file is unsafe to run in signal handler(many reasons)!
sa.sa_handler = reread_config_file;
sigaction_set(SIGHUP, &sa);
//FIXME: reap_child is unsafe to run in signal handler (uses stdio)!
sa.sa_handler = reap_child;
sigaction_set(SIGCHLD, &sa);
//FIXME: clean_up_and_exit is unsafe to run in signal handler (uses stdio)!
sa.sa_handler = clean_up_and_exit;
sigaction_set(SIGTERM, &sa);
sa.sa_handler = clean_up_and_exit;
sigaction_set(SIGINT, &sa);
sa.sa_handler = SIG_IGN;
sigaction(SIGPIPE, &sa, &saved_pipe_handler);
reread_config_file(SIGHUP); /* load config from file */
for (;;) {
int ready_fd_cnt;
int ctrl, accepted_fd, new_udp_fd;
fd_set readable;
if (maxsock < 0)
recalculate_maxsock();
readable = allsock; /* struct copy */
/* if there are no fds to wait on, we will block
* until signal wakes us up (maxsock == 0, but readable
* never contains fds 0 and 1...) */
ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
if (ready_fd_cnt < 0) {
if (errno != EINTR) {
bb_simple_perror_msg("select");
sleep1();
}
continue;
}
dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
continue;
dbg("ready fd:%d\n", sep->se_fd);
ready_fd_cnt--;
ctrl = sep->se_fd;
accepted_fd = -1;
new_udp_fd = -1;
if (!sep->se_wait) {
if (sep->se_socktype == SOCK_STREAM) {
ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
dbg("accepted_fd:%d\n", accepted_fd);
if (ctrl < 0) {
if (errno != EINTR)
bb_perror_msg("accept (for %s)", sep->se_service);
continue;
}
}
/* "nowait" udp */
if (sep->se_socktype == SOCK_DGRAM
&& sep->se_family != AF_UNIX
) {
/* How udp "nowait" works:
* child peeks at (received and buffered by kernel) UDP packet,
* performs connect() on the socket so that it is linked only
* to this peer. But this also affects parent, because descriptors
* are shared after fork() a-la dup(). When parent performs
* select(), it will see this descriptor connected to the peer (!)
* and still readable, will act on it and mess things up
* (can create many copies of same child, etc).
* Parent must create and use new socket instead. */
new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
dbg("new_udp_fd:%d\n", new_udp_fd);
if (new_udp_fd < 0) { /* error: eat packet, forget about it */
udp_err:
recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
continue;
}
setsockopt_reuseaddr(new_udp_fd);
/* TODO: better do bind after fork in parent,
* so that we don't have two wildcard bound sockets
* even for a brief moment? */
if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
dbg("bind(new_udp_fd) failed\n");
close(new_udp_fd);
goto udp_err;
}
dbg("bind(new_udp_fd) succeeded\n");
}
}
block_CHLD_HUP_ALRM(&omask);
pid = 0;
#ifdef INETD_BUILTINS_ENABLED
/* do we need to fork? */
if (sep->se_builtin == NULL
|| (sep->se_socktype == SOCK_STREAM
&& sep->se_builtin->bi_fork))
#endif
{
if (sep->se_max != 0) {
if (++sep->se_count == 1)
sep->se_time = monotonic_sec();
else if (sep->se_count >= sep->se_max) {
unsigned now = monotonic_sec();
/* did we accumulate se_max connects too quickly? */
if (now - sep->se_time <= CNT_INTERVAL) {
bb_error_msg("%s/%s: too many connections, pausing",
sep->se_service, sep->se_proto);
remove_fd_from_set(sep->se_fd);
close(sep->se_fd);
sep->se_fd = -1;
sep->se_count = 0;
rearm_alarm(); /* will revive it in RETRYTIME sec */
restore_sigmask(&omask);
maybe_close(new_udp_fd);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
sep->se_count = 0;
}
}
/* on NOMMU, streamed chargen
* builtin wouldn't work, but it is
* not allowed on NOMMU (ifdefed out) */
#ifdef INETD_BUILTINS_ENABLED
if (BB_MMU && sep->se_builtin)
pid = fork();
else
#endif
pid = vfork();
if (pid < 0) { /* fork error */
bb_simple_perror_msg("vfork"+1);
sleep1();
restore_sigmask(&omask);
maybe_close(new_udp_fd);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
if (pid == 0)
pid--; /* -1: "we did fork and we are child" */
}
/* if pid == 0 here, we didn't fork */
if (pid > 0) { /* parent */
if (sep->se_wait) {
/* wait: we passed socket to child,
* will wait for child to terminate */
sep->se_wait = pid;
remove_fd_from_set(sep->se_fd);
}
if (new_udp_fd >= 0) {
/* udp nowait: child connected the socket,
* we created and will use new, unconnected one */
xmove_fd(new_udp_fd, sep->se_fd);
dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
}
restore_sigmask(&omask);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
/* we are either child or didn't fork at all */
#ifdef INETD_BUILTINS_ENABLED
if (sep->se_builtin) {
if (pid) { /* "pid" is -1: we did fork */
close(sep->se_fd); /* listening socket */
dbg("closed sep->se_fd:%d\n", sep->se_fd);
logmode = LOGMODE_NONE; /* make xwrite etc silent */
}
restore_sigmask(&omask);
if (sep->se_socktype == SOCK_STREAM)
sep->se_builtin->bi_stream_fn(ctrl, sep);
else
sep->se_builtin->bi_dgram_fn(ctrl, sep);
if (pid) /* we did fork */
_exit(EXIT_FAILURE);
maybe_close(accepted_fd);
continue; /* -> check next fd in fd set */
}
#endif
/* child */
setsid();
/* "nowait" udp */
if (new_udp_fd >= 0) {
len_and_sockaddr *lsa;
int r;
close(new_udp_fd);
dbg("closed new_udp_fd:%d\n", new_udp_fd);
lsa = xzalloc_lsa(sep->se_family);
/* peek at the packet and remember peer addr */
r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
&lsa->u.sa, &lsa->len);
if (r < 0)
goto do_exit1;
/* make this socket "connected" to peer addr:
* only packets from this peer will be recv'ed,
* and bare write()/send() will work on it */
connect(ctrl, &lsa->u.sa, lsa->len);
dbg("connected ctrl:%d to remote peer\n", ctrl);
free(lsa);
}
/* prepare env and exec program */
pwd = getpwnam(sep->se_user);
if (pwd == NULL) {
bb_error_msg("%s: no such %s", sep->se_user, "user");
goto do_exit1;
}
if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
bb_error_msg("%s: no such %s", sep->se_group, "group");
goto do_exit1;
}
if (real_uid != 0 && real_uid != pwd->pw_uid) {
/* a user running private inetd */
bb_simple_error_msg("non-root must run services as himself");
goto do_exit1;
}
if (pwd->pw_uid != real_uid) {
if (sep->se_group)
pwd->pw_gid = grp->gr_gid;
/* initgroups, setgid, setuid: */
change_identity(pwd);
} else if (sep->se_group) {
xsetgid(grp->gr_gid);
setgroups(1, &grp->gr_gid);
}
if (rlim_ofile.rlim_cur != rlim_ofile_cur)
if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
bb_simple_perror_msg("setrlimit");
/* closelog(); - WRONG. we are after vfork,
* this may confuse syslog() internal state.
* Let's hope libc sets syslog fd to CLOEXEC...
*/
xmove_fd(ctrl, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
/* manpages of inetd I managed to find either say
* that stderr is also redirected to the network,
* or do not talk about redirection at all (!) */
if (!sep->se_wait) /* only for usual "tcp nowait" */
xdup2(STDIN_FILENO, STDERR_FILENO);
/* NB: among others, this loop closes listening sockets
* for nowait stream children */
for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
if (sep2->se_fd != ctrl)
maybe_close(sep2->se_fd);
sigaction_set(SIGPIPE, &saved_pipe_handler);
restore_sigmask(&omask);
dbg("execing:'%s'\n", sep->se_program);
BB_EXECVP(sep->se_program, sep->se_argv);
bb_perror_msg("can't execute '%s'", sep->se_program);
do_exit1:
/* eat packet in udp case */
if (sep->se_socktype != SOCK_STREAM)
recv(0, line, LINE_SIZE, MSG_DONTWAIT);
_exit(EXIT_FAILURE);
} /* for (sep = servtab...) */
} /* for (;;) */
}
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
|| ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
# if !BB_MMU
static const char *const cat_args[] = { "cat", NULL };
# endif
#endif
/*
* Internet services provided internally by inetd:
*/
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
/* Echo service -- echo data back. */
/* ARGSUSED */
static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
{
# if BB_MMU
while (1) {
ssize_t sz = safe_read(s, line, LINE_SIZE);
if (sz <= 0)
break;
xwrite(s, line, sz);
}
# else
/* We are after vfork here! */
/* move network socket to stdin/stdout */
xmove_fd(s, STDIN_FILENO);
xdup2(STDIN_FILENO, STDOUT_FILENO);
/* no error messages please... */
close(STDERR_FILENO);
xopen(bb_dev_null, O_WRONLY);
BB_EXECVP("cat", (char**)cat_args);
/* on failure we return to main, which does exit(EXIT_FAILURE) */
# endif
}
static void FAST_FUNC echo_dg(int s, servtab_t *sep)
{
enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
char *buf = xmalloc(BUFSIZE); /* too big for stack */
int sz;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
/* dgram builtins are non-forking - DONT BLOCK! */
sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
if (sz > 0)
sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
free(buf);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
/* Discard service -- ignore data. */
/* ARGSUSED */
static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
{
# if BB_MMU
while (safe_read(s, line, LINE_SIZE) > 0)
continue;
# else
/* We are after vfork here! */
/* move network socket to stdin */
xmove_fd(s, STDIN_FILENO);
/* discard output */
close(STDOUT_FILENO);
xopen(bb_dev_null, O_WRONLY);
/* no error messages please... */
xdup2(STDOUT_FILENO, STDERR_FILENO);
BB_EXECVP("cat", (char**)cat_args);
/* on failure we return to main, which does exit(EXIT_FAILURE) */
# endif
}
/* ARGSUSED */
static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
{
/* dgram builtins are non-forking - DONT BLOCK! */
recv(s, line, LINE_SIZE, MSG_DONTWAIT);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
#define LINESIZ 72
static void init_ring(void)
{
int i;
end_ring = ring;
for (i = ' '; i < 127; i++)
*end_ring++ = i;
}
/* Character generator. MMU arches only. */
/* ARGSUSED */
static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
{
char *rs;
int len;
char text[LINESIZ + 2];
if (!end_ring) {
init_ring();
rs = ring;
}
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
rs = ring;
for (;;) {
len = end_ring - rs;
if (len >= LINESIZ)
memmove(text, rs, LINESIZ);
else {
memmove(text, rs, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++rs == end_ring)
rs = ring;
xwrite(s, text, sizeof(text));
}
}
/* ARGSUSED */
static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
{
int len;
char text[LINESIZ + 2];
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
/* Eat UDP packet which started it all */
/* dgram builtins are non-forking - DONT BLOCK! */
lsa->len = sep->se_lsa->len;
if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
if (!end_ring) {
init_ring();
ring_pos = ring;
}
len = end_ring - ring_pos;
if (len >= LINESIZ)
memmove(text, ring_pos, LINESIZ);
else {
memmove(text, ring_pos, len);
memmove(text + len, ring, LINESIZ - len);
}
if (++ring_pos == end_ring)
ring_pos = ring;
text[LINESIZ] = '\r';
text[LINESIZ + 1] = '\n';
sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_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 NOINLINE uint32_t machtime(void)
{
struct timeval tv;
xgettimeofday(&tv);
return htonl((uint32_t)(tv.tv_sec + 2208988800U));
}
/* ARGSUSED */
static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
{
uint32_t result;
result = machtime();
full_write(s, &result, sizeof(result));
}
static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
{
uint32_t result;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
result = machtime();
sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
/* Return human-readable time of day */
/* ARGSUSED */
static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
{
time_t t;
time(&t);
fdprintf(s, "%.24s\r\n", ctime(&t));
}
static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
{
time_t t;
len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
lsa->len = sep->se_lsa->len;
if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
return;
t = time(NULL);
sprintf(line, "%.24s\r\n", ctime(&t));
sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
}
#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
|