source: MondoRescue/branches/3.3/mindi-busybox/networking/inetd.c@ 3621

Last change on this file since 3621 was 3621, checked in by Bruno Cornec, 7 years ago

New 3?3 banch for incorporation of latest busybox 1.25. Changing minor version to handle potential incompatibilities.
File size: 49.3 KB
Line 
1/* vi: set sw=4 ts=4: */
2/* $Slackware: inetd.c 1.79s 2001/02/06 13:18:00 volkerdi Exp $ */
3/* $OpenBSD: inetd.c,v 1.79 2001/01/30 08:30:57 deraadt Exp $ */
4/* $NetBSD: inetd.c,v 1.11 1996/02/22 11:14:41 mycroft Exp $ */
5/* Busybox port by Vladimir Oleynik (C) 2001-2005 <dzo@simtreas.ru> */
6/* IPv6 support, many bug fixes by Denys Vlasenko (c) 2008 */
7/*
8 * Copyright (c) 1983,1991 The Regents of the University of California.
9 * All rights reserved.
10 *
11 * Redistribution and use in source and binary forms, with or without
12 * modification, are permitted provided that the following conditions
13 * are met:
14 * 1. Redistributions of source code must retain the above copyright
15 * notice, this list of conditions and the following disclaimer.
16 * 2. Redistributions in binary form must reproduce the above copyright
17 * notice, this list of conditions and the following disclaimer in the
18 * documentation and/or other materials provided with the distribution.
19 * 3. All advertising materials mentioning features or use of this software
20 * must display the following acknowledgement:
21 * This product includes software developed by the University of
22 * California, Berkeley and its contributors.
23 * 4. Neither the name of the University nor the names of its contributors
24 * may be used to endorse or promote products derived from this software
25 * without specific prior written permission.
26 *
27 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS "AS IS" AND
28 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37 * SUCH DAMAGE.
38 */
39
40/* Inetd - Internet super-server
41 *
42 * This program invokes configured services when a connection
43 * from a peer is established or a datagram arrives.
44 * Connection-oriented services are invoked each time a
45 * connection is made, by creating a process. This process
46 * is passed the connection as file descriptor 0 and is
47 * expected to do a getpeername to find out peer's host
48 * and port.
49 * Datagram oriented services are invoked when a datagram
50 * arrives; a process is created and passed a pending message
51 * on file descriptor 0. peer's address can be obtained
52 * using recvfrom.
53 *
54 * Inetd uses a configuration file which is read at startup
55 * and, possibly, at some later time in response to a hangup signal.
56 * The configuration file is "free format" with fields given in the
57 * order shown below. Continuation lines for an entry must begin with
58 * a space or tab. All fields must be present in each entry.
59 *
60 * service_name must be in /etc/services
61 * socket_type stream/dgram/raw/rdm/seqpacket
62 * protocol must be in /etc/protocols
63 * (usually "tcp" or "udp")
64 * wait/nowait[.max] single-threaded/multi-threaded, max #
65 * user[.group] or user[:group] user/group to run daemon as
66 * server_program full path name
67 * server_program_arguments maximum of MAXARGS (20)
68 *
69 * For RPC services
70 * service_name/version must be in /etc/rpc
71 * socket_type stream/dgram/raw/rdm/seqpacket
72 * rpc/protocol "rpc/tcp" etc
73 * wait/nowait[.max] single-threaded/multi-threaded
74 * user[.group] or user[:group] user to run daemon as
75 * server_program full path name
76 * server_program_arguments maximum of MAXARGS (20)
77 *
78 * For non-RPC services, the "service name" can be of the form
79 * hostaddress:servicename, in which case the hostaddress is used
80 * as the host portion of the address to listen on. If hostaddress
81 * consists of a single '*' character, INADDR_ANY is used.
82 *
83 * A line can also consist of just
84 * hostaddress:
85 * where hostaddress is as in the preceding paragraph. Such a line must
86 * have no further fields; the specified hostaddress is remembered and
87 * used for all further lines that have no hostaddress specified,
88 * until the next such line (or EOF). (This is why * is provided to
89 * allow explicit specification of INADDR_ANY.) A line
90 * *:
91 * is implicitly in effect at the beginning of the file.
92 *
93 * The hostaddress specifier may (and often will) contain dots;
94 * the service name must not.
95 *
96 * For RPC services, host-address specifiers are accepted and will
97 * work to some extent; however, because of limitations in the
98 * portmapper interface, it will not work to try to give more than
99 * one line for any given RPC service, even if the host-address
100 * specifiers are different.
101 *
102 * Comment lines are indicated by a '#' in column 1.
103 */
104
105/* inetd rules for passing file descriptors to children
106 * (http://www.freebsd.org/cgi/man.cgi?query=inetd):
107 *
108 * The wait/nowait entry specifies whether the server that is invoked by
109 * inetd will take over the socket associated with the service access point,
110 * and thus whether inetd should wait for the server to exit before listen-
111 * ing for new service requests. Datagram servers must use "wait", as
112 * they are always invoked with the original datagram socket bound to the
113 * specified service address. These servers must read at least one datagram
114 * from the socket before exiting. If a datagram server connects to its
115 * peer, freeing the socket so inetd can receive further messages on the
116 * socket, it is said to be a "multi-threaded" server; it should read one
117 * datagram from the socket and create a new socket connected to the peer.
118 * It should fork, and the parent should then exit to allow inetd to check
119 * for new service requests to spawn new servers. Datagram servers which
120 * process all incoming datagrams on a socket and eventually time out are
121 * said to be "single-threaded". The comsat(8), biff(1) and talkd(8)
122 * utilities are both examples of the latter type of datagram server. The
123 * tftpd(8) utility is an example of a multi-threaded datagram server.
124 *
125 * Servers using stream sockets generally are multi-threaded and use the
126 * "nowait" entry. Connection requests for these services are accepted by
127 * inetd, and the server is given only the newly-accepted socket connected
128 * to a client of the service. Most stream-based services operate in this
129 * manner. Stream-based servers that use "wait" are started with the lis-
130 * tening service socket, and must accept at least one connection request
131 * before exiting. Such a server would normally accept and process incoming
132 * connection requests until a timeout.
133 */
134
135/* Despite of above doc saying that dgram services must use "wait",
136 * "udp nowait" servers are implemented in busyboxed inetd.
137 * IPv6 addresses are also implemented. However, they may look ugly -
138 * ":::service..." means "address '::' (IPv6 wildcard addr)":"service"...
139 * You have to put "tcp6"/"udp6" in protocol field to select IPv6.
140 */
141
142/* Here's the scoop concerning the user[:group] feature:
143 * 1) group is not specified:
144 * a) user = root: NO setuid() or setgid() is done
145 * b) other: initgroups(name, primary group)
146 * setgid(primary group as found in passwd)
147 * setuid()
148 * 2) group is specified:
149 * a) user = root: setgid(specified group)
150 * NO initgroups()
151 * NO setuid()
152 * b) other: initgroups(name, specified group)
153 * setgid(specified group)
154 * setuid()
155 */
156
157//usage:#define inetd_trivial_usage
158//usage: "[-fe] [-q N] [-R N] [CONFFILE]"
159//usage:#define inetd_full_usage "\n\n"
160//usage: "Listen for network connections and launch programs\n"
161//usage: "\n -f Run in foreground"
162//usage: "\n -e Log to stderr"
163//usage: "\n -q N Socket listen queue (default: 128)"
164//usage: "\n -R N Pause services after N connects/min"
165//usage: "\n (default: 0 - disabled)"
166
167#include <syslog.h>
168#include <sys/resource.h> /* setrlimit */
169#include <sys/socket.h> /* un.h may need this */
170#include <sys/un.h>
171
172#include "libbb.h"
173#include "common_bufsiz.h"
174
175#if ENABLE_FEATURE_INETD_RPC
176# if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
177# error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support"
178# endif
179# include <rpc/rpc.h>
180# include <rpc/pmap_clnt.h>
181#endif
182
183#if !BB_MMU
184/* stream version of chargen is forking but not execing,
185 * can't do that (easily) on NOMMU */
186#undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
187#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
188#endif
189
190#define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
191#define RETRYTIME 60 /* retry after bind or server fail */
192
193// TODO: explain, or get rid of setrlimit games
194
195#ifndef RLIMIT_NOFILE
196#define RLIMIT_NOFILE RLIMIT_OFILE
197#endif
198
199#ifndef OPEN_MAX
200#define OPEN_MAX 64
201#endif
202
203/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
204#define FD_MARGIN 8
205
206#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
207 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
208 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
209 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
210 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
211# define INETD_BUILTINS_ENABLED
212#endif
213
214typedef struct servtab_t {
215 /* The most frequently referenced one: */
216 int se_fd; /* open descriptor */
217 /* NB: 'biggest fields last' saves on code size (~250 bytes) */
218 /* [addr:]service socktype proto wait user[:group] prog [args] */
219 char *se_local_hostname; /* addr to listen on */
220 char *se_service; /* "80" or "www" or "mount/2[-3]" */
221 /* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
222 char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
223#if ENABLE_FEATURE_INETD_RPC
224 int se_rpcprog; /* rpc program number */
225 int se_rpcver_lo; /* rpc program lowest version */
226 int se_rpcver_hi; /* rpc program highest version */
227#define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
228#else
229#define is_rpc_service(sep) 0
230#endif
231 pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
232 /* and waiting for this pid */
233 socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
234 family_t se_family; /* AF_UNIX/INET[6] */
235 /* se_proto_no is used by RPC code only... hmm */
236 smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
237 smallint se_checked; /* looked at during merge */
238 unsigned se_max; /* allowed instances per minute */
239 unsigned se_count; /* number started since se_time */
240 unsigned se_time; /* when we started counting */
241 char *se_user; /* user name to run as */
242 char *se_group; /* group name to run as, can be NULL */
243#ifdef INETD_BUILTINS_ENABLED
244 const struct builtin *se_builtin; /* if built-in, description */
245#endif
246 struct servtab_t *se_next;
247 len_and_sockaddr *se_lsa;
248 char *se_program; /* server program */
249#define MAXARGV 20
250 char *se_argv[MAXARGV + 1]; /* program arguments */
251} servtab_t;
252
253#ifdef INETD_BUILTINS_ENABLED
254/* Echo received data */
255#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
256static void FAST_FUNC echo_stream(int, servtab_t *);
257static void FAST_FUNC echo_dg(int, servtab_t *);
258#endif
259/* Internet /dev/null */
260#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
261static void FAST_FUNC discard_stream(int, servtab_t *);
262static void FAST_FUNC discard_dg(int, servtab_t *);
263#endif
264/* Return 32 bit time since 1900 */
265#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
266static void FAST_FUNC machtime_stream(int, servtab_t *);
267static void FAST_FUNC machtime_dg(int, servtab_t *);
268#endif
269/* Return human-readable time */
270#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
271static void FAST_FUNC daytime_stream(int, servtab_t *);
272static void FAST_FUNC daytime_dg(int, servtab_t *);
273#endif
274/* Familiar character generator */
275#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
276static void FAST_FUNC chargen_stream(int, servtab_t *);
277static void FAST_FUNC chargen_dg(int, servtab_t *);
278#endif
279
280struct builtin {
281 /* NB: not necessarily NUL terminated */
282 char bi_service7[7]; /* internally provided service name */
283 uint8_t bi_fork; /* 1 if stream fn should run in child */
284 void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
285 void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
286};
287
288static const struct builtin builtins[] = {
289#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
290 { "echo", 1, echo_stream, echo_dg },
291#endif
292#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
293 { "discard", 1, discard_stream, discard_dg },
294#endif
295#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
296 { "chargen", 1, chargen_stream, chargen_dg },
297#endif
298#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
299 { "time", 0, machtime_stream, machtime_dg },
300#endif
301#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
302 { "daytime", 0, daytime_stream, daytime_dg },
303#endif
304};
305#endif /* INETD_BUILTINS_ENABLED */
306
307struct globals {
308 rlim_t rlim_ofile_cur;
309 struct rlimit rlim_ofile;
310 servtab_t *serv_list;
311 int global_queuelen;
312 int maxsock; /* max fd# in allsock, -1: unknown */
313 /* whenever maxsock grows, prev_maxsock is set to new maxsock,
314 * but if maxsock is set to -1, prev_maxsock is not changed */
315 int prev_maxsock;
316 unsigned max_concurrency;
317 smallint alarm_armed;
318 uid_t real_uid; /* user ID who ran us */
319 const char *config_filename;
320 parser_t *parser;
321 char *default_local_hostname;
322#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
323 char *end_ring;
324 char *ring_pos;
325 char ring[128];
326#endif
327 fd_set allsock;
328 /* Used in next_line(), and as scratch read buffer */
329 char line[256]; /* _at least_ 256, see LINE_SIZE */
330} FIX_ALIASING;
331#define G (*(struct globals*)bb_common_bufsiz1)
332enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
333#define rlim_ofile_cur (G.rlim_ofile_cur )
334#define rlim_ofile (G.rlim_ofile )
335#define serv_list (G.serv_list )
336#define global_queuelen (G.global_queuelen)
337#define maxsock (G.maxsock )
338#define prev_maxsock (G.prev_maxsock )
339#define max_concurrency (G.max_concurrency)
340#define alarm_armed (G.alarm_armed )
341#define real_uid (G.real_uid )
342#define config_filename (G.config_filename)
343#define parser (G.parser )
344#define default_local_hostname (G.default_local_hostname)
345#define first_ps_byte (G.first_ps_byte )
346#define last_ps_byte (G.last_ps_byte )
347#define end_ring (G.end_ring )
348#define ring_pos (G.ring_pos )
349#define ring (G.ring )
350#define allsock (G.allsock )
351#define line (G.line )
352#define INIT_G() do { \
353 setup_common_bufsiz(); \
354 BUILD_BUG_ON(sizeof(G) > COMMON_BUFSIZE); \
355 rlim_ofile_cur = OPEN_MAX; \
356 global_queuelen = 128; \
357 config_filename = "/etc/inetd.conf"; \
358} while (0)
359
360#if 1
361# define dbg(...) ((void)0)
362#else
363# define dbg(...) \
364do { \
365 int dbg_fd = open("inetd_debug.log", O_WRONLY | O_CREAT | O_APPEND, 0666); \
366 if (dbg_fd >= 0) { \
367 fdprintf(dbg_fd, "%d: ", getpid()); \
368 fdprintf(dbg_fd, __VA_ARGS__); \
369 close(dbg_fd); \
370 } \
371} while (0)
372#endif
373
374static void maybe_close(int fd)
375{
376 if (fd >= 0) {
377 close(fd);
378 dbg("closed fd:%d\n", fd);
379 }
380}
381
382// TODO: move to libbb?
383static len_and_sockaddr *xzalloc_lsa(int family)
384{
385 len_and_sockaddr *lsa;
386 int sz;
387
388 sz = sizeof(struct sockaddr_in);
389 if (family == AF_UNIX)
390 sz = sizeof(struct sockaddr_un);
391#if ENABLE_FEATURE_IPV6
392 if (family == AF_INET6)
393 sz = sizeof(struct sockaddr_in6);
394#endif
395 lsa = xzalloc(LSA_LEN_SIZE + sz);
396 lsa->len = sz;
397 lsa->u.sa.sa_family = family;
398 return lsa;
399}
400
401static void rearm_alarm(void)
402{
403 if (!alarm_armed) {
404 alarm_armed = 1;
405 alarm(RETRYTIME);
406 }
407}
408
409static void block_CHLD_HUP_ALRM(sigset_t *m)
410{
411 sigemptyset(m);
412 sigaddset(m, SIGCHLD);
413 sigaddset(m, SIGHUP);
414 sigaddset(m, SIGALRM);
415 sigprocmask(SIG_BLOCK, m, m); /* old sigmask is stored in m */
416}
417
418static void restore_sigmask(sigset_t *m)
419{
420 sigprocmask(SIG_SETMASK, m, NULL);
421}
422
423#if ENABLE_FEATURE_INETD_RPC
424static void register_rpc(servtab_t *sep)
425{
426 int n;
427 struct sockaddr_in ir_sin;
428 socklen_t size;
429
430 size = sizeof(ir_sin);
431 if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
432 bb_perror_msg("getsockname");
433 return;
434 }
435
436 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
437 pmap_unset(sep->se_rpcprog, n);
438 if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
439 bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
440 sep->se_service, sep->se_proto,
441 sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
442 }
443}
444
445static void unregister_rpc(servtab_t *sep)
446{
447 int n;
448
449 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
450 if (!pmap_unset(sep->se_rpcprog, n))
451 bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
452 }
453}
454#endif /* FEATURE_INETD_RPC */
455
456static void bump_nofile(void)
457{
458 enum { FD_CHUNK = 32 };
459 struct rlimit rl;
460
461 /* Never fails under Linux (except if you pass it bad arguments) */
462 getrlimit(RLIMIT_NOFILE, &rl);
463 rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
464 rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
465 if (rl.rlim_cur <= rlim_ofile_cur) {
466 bb_error_msg("can't extend file limit, max = %d",
467 (int) rl.rlim_cur);
468 return;
469 }
470
471 if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
472 bb_perror_msg("setrlimit");
473 return;
474 }
475
476 rlim_ofile_cur = rl.rlim_cur;
477}
478
479static void remove_fd_from_set(int fd)
480{
481 if (fd >= 0) {
482 FD_CLR(fd, &allsock);
483 dbg("stopped listening on fd:%d\n", fd);
484 maxsock = -1;
485 dbg("maxsock:%d\n", maxsock);
486 }
487}
488
489static void add_fd_to_set(int fd)
490{
491 if (fd >= 0) {
492 FD_SET(fd, &allsock);
493 dbg("started listening on fd:%d\n", fd);
494 if (maxsock >= 0 && fd > maxsock) {
495 prev_maxsock = maxsock = fd;
496 dbg("maxsock:%d\n", maxsock);
497 if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
498 bump_nofile();
499 }
500 }
501}
502
503static void recalculate_maxsock(void)
504{
505 int fd = 0;
506
507 /* We may have no services, in this case maxsock should still be >= 0
508 * (code elsewhere is not happy with maxsock == -1) */
509 maxsock = 0;
510 while (fd <= prev_maxsock) {
511 if (FD_ISSET(fd, &allsock))
512 maxsock = fd;
513 fd++;
514 }
515 dbg("recalculated maxsock:%d\n", maxsock);
516 prev_maxsock = maxsock;
517 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
518 bump_nofile();
519}
520
521static void prepare_socket_fd(servtab_t *sep)
522{
523 int r, fd;
524
525 fd = socket(sep->se_family, sep->se_socktype, 0);
526 if (fd < 0) {
527 bb_perror_msg("socket");
528 return;
529 }
530 setsockopt_reuseaddr(fd);
531
532#if ENABLE_FEATURE_INETD_RPC
533 if (is_rpc_service(sep)) {
534 struct passwd *pwd;
535
536 /* zero out the port for all RPC services; let bind()
537 * find one. */
538 set_nport(&sep->se_lsa->u.sa, 0);
539
540 /* for RPC services, attempt to use a reserved port
541 * if they are going to be running as root. */
542 if (real_uid == 0 && sep->se_family == AF_INET
543 && (pwd = getpwnam(sep->se_user)) != NULL
544 && pwd->pw_uid == 0
545 ) {
546 r = bindresvport(fd, &sep->se_lsa->u.sin);
547 } else {
548 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
549 }
550 if (r == 0) {
551 int saveerrno = errno;
552 /* update lsa with port# */
553 getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
554 errno = saveerrno;
555 }
556 } else
557#endif
558 {
559 if (sep->se_family == AF_UNIX) {
560 struct sockaddr_un *sun;
561 sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
562 unlink(sun->sun_path);
563 }
564 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
565 }
566 if (r < 0) {
567 bb_perror_msg("%s/%s: bind",
568 sep->se_service, sep->se_proto);
569 close(fd);
570 rearm_alarm();
571 return;
572 }
573
574 if (sep->se_socktype == SOCK_STREAM) {
575 listen(fd, global_queuelen);
576 dbg("new sep->se_fd:%d (stream)\n", fd);
577 } else {
578 dbg("new sep->se_fd:%d (!stream)\n", fd);
579 }
580
581 add_fd_to_set(fd);
582 sep->se_fd = fd;
583}
584
585static int reopen_config_file(void)
586{
587 free(default_local_hostname);
588 default_local_hostname = xstrdup("*");
589 if (parser != NULL)
590 config_close(parser);
591 parser = config_open(config_filename);
592 return (parser != NULL);
593}
594
595static void close_config_file(void)
596{
597 if (parser) {
598 config_close(parser);
599 parser = NULL;
600 }
601}
602
603static void free_servtab_strings(servtab_t *cp)
604{
605 int i;
606
607 free(cp->se_local_hostname);
608 free(cp->se_service);
609 free(cp->se_proto);
610 free(cp->se_user);
611 free(cp->se_group);
612 free(cp->se_lsa); /* not a string in fact */
613 free(cp->se_program);
614 for (i = 0; i < MAXARGV; i++)
615 free(cp->se_argv[i]);
616}
617
618static servtab_t *new_servtab(void)
619{
620 servtab_t *newtab = xzalloc(sizeof(servtab_t));
621 newtab->se_fd = -1; /* paranoia */
622 return newtab;
623}
624
625static servtab_t *dup_servtab(servtab_t *sep)
626{
627 servtab_t *newtab;
628 int argc;
629
630 newtab = new_servtab();
631 *newtab = *sep; /* struct copy */
632 /* deep-copying strings */
633 newtab->se_service = xstrdup(newtab->se_service);
634 newtab->se_proto = xstrdup(newtab->se_proto);
635 newtab->se_user = xstrdup(newtab->se_user);
636 newtab->se_group = xstrdup(newtab->se_group);
637 newtab->se_program = xstrdup(newtab->se_program);
638 for (argc = 0; argc <= MAXARGV; argc++)
639 newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
640 /* NB: se_fd, se_hostaddr and se_next are always
641 * overwrittend by callers, so we don't bother resetting them
642 * to NULL/0/-1 etc */
643
644 return newtab;
645}
646
647/* gcc generates much more code if this is inlined */
648static NOINLINE servtab_t *parse_one_line(void)
649{
650 int argc;
651 char *token[6+MAXARGV];
652 char *p, *arg;
653 char *hostdelim;
654 servtab_t *sep;
655 servtab_t *nsep;
656 new:
657 sep = new_servtab();
658 more:
659 argc = config_read(parser, token, 6+MAXARGV, 1, "# \t", PARSE_NORMAL);
660 if (!argc) {
661 free(sep);
662 return NULL;
663 }
664
665 /* [host:]service socktype proto wait user[:group] prog [args] */
666 /* Check for "host:...." line */
667 arg = token[0];
668 hostdelim = strrchr(arg, ':');
669 if (hostdelim) {
670 *hostdelim = '\0';
671 sep->se_local_hostname = xstrdup(arg);
672 arg = hostdelim + 1;
673 if (*arg == '\0' && argc == 1) {
674 /* Line has just "host:", change the
675 * default host for the following lines. */
676 free(default_local_hostname);
677 default_local_hostname = sep->se_local_hostname;
678 /*sep->se_local_hostname = NULL; - redundant */
679 /* (we'll overwrite this field anyway) */
680 goto more;
681 }
682 } else
683 sep->se_local_hostname = xstrdup(default_local_hostname);
684
685 /* service socktype proto wait user[:group] prog [args] */
686 sep->se_service = xstrdup(arg);
687
688 /* socktype proto wait user[:group] prog [args] */
689 if (argc < 6) {
690 parse_err:
691 bb_error_msg("parse error on line %u, line is ignored",
692 parser->lineno);
693 /* Just "goto more" can make sep to carry over e.g.
694 * "rpc"-ness (by having se_rpcver_lo != 0).
695 * We will be more paranoid: */
696 free_servtab_strings(sep);
697 free(sep);
698 goto new;
699 }
700
701 {
702 static const int8_t SOCK_xxx[] ALIGN1 = {
703 -1,
704 SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
705 SOCK_SEQPACKET, SOCK_RAW
706 };
707 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
708 "stream""\0" "dgram""\0" "rdm""\0"
709 "seqpacket""\0" "raw""\0"
710 , token[1])];
711 }
712
713 /* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
714 sep->se_proto = arg = xstrdup(token[2]);
715 if (strcmp(arg, "unix") == 0) {
716 sep->se_family = AF_UNIX;
717 } else {
718 char *six;
719 sep->se_family = AF_INET;
720 six = last_char_is(arg, '6');
721 if (six) {
722#if ENABLE_FEATURE_IPV6
723 *six = '\0';
724 sep->se_family = AF_INET6;
725#else
726 bb_error_msg("%s: no support for IPv6", sep->se_proto);
727 goto parse_err;
728#endif
729 }
730 if (is_prefixed_with(arg, "rpc/")) {
731#if ENABLE_FEATURE_INETD_RPC
732 unsigned n;
733 arg += 4;
734 p = strchr(sep->se_service, '/');
735 if (p == NULL) {
736 bb_error_msg("no rpc version: '%s'", sep->se_service);
737 goto parse_err;
738 }
739 *p++ = '\0';
740 n = bb_strtou(p, &p, 10);
741 if (n > INT_MAX) {
742 bad_ver_spec:
743 bb_error_msg("bad rpc version");
744 goto parse_err;
745 }
746 sep->se_rpcver_lo = sep->se_rpcver_hi = n;
747 if (*p == '-') {
748 p++;
749 n = bb_strtou(p, &p, 10);
750 if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
751 goto bad_ver_spec;
752 sep->se_rpcver_hi = n;
753 }
754 if (*p != '\0')
755 goto bad_ver_spec;
756#else
757 bb_error_msg("no support for rpc services");
758 goto parse_err;
759#endif
760 }
761 /* we don't really need getprotobyname()! */
762 if (strcmp(arg, "tcp") == 0)
763 sep->se_proto_no = IPPROTO_TCP; /* = 6 */
764 if (strcmp(arg, "udp") == 0)
765 sep->se_proto_no = IPPROTO_UDP; /* = 17 */
766 if (six)
767 *six = '6';
768 if (!sep->se_proto_no) /* not tcp/udp?? */
769 goto parse_err;
770 }
771
772 /* [no]wait[.max] user[:group] prog [args] */
773 arg = token[3];
774 sep->se_max = max_concurrency;
775 p = strchr(arg, '.');
776 if (p) {
777 *p++ = '\0';
778 sep->se_max = bb_strtou(p, NULL, 10);
779 if (errno)
780 goto parse_err;
781 }
782 sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
783 if (!sep->se_wait) /* "no" seen */
784 arg += 2;
785 if (strcmp(arg, "wait") != 0)
786 goto parse_err;
787
788 /* user[:group] prog [args] */
789 sep->se_user = xstrdup(token[4]);
790 arg = strchr(sep->se_user, '.');
791 if (arg == NULL)
792 arg = strchr(sep->se_user, ':');
793 if (arg) {
794 *arg++ = '\0';
795 sep->se_group = xstrdup(arg);
796 }
797
798 /* prog [args] */
799 sep->se_program = xstrdup(token[5]);
800#ifdef INETD_BUILTINS_ENABLED
801 if (strcmp(sep->se_program, "internal") == 0
802 && strlen(sep->se_service) <= 7
803 && (sep->se_socktype == SOCK_STREAM
804 || sep->se_socktype == SOCK_DGRAM)
805 ) {
806 unsigned i;
807 for (i = 0; i < ARRAY_SIZE(builtins); i++)
808 if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
809 goto found_bi;
810 bb_error_msg("unknown internal service %s", sep->se_service);
811 goto parse_err;
812 found_bi:
813 sep->se_builtin = &builtins[i];
814 /* stream builtins must be "nowait", dgram must be "wait" */
815 if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
816 goto parse_err;
817 }
818#endif
819 argc = 0;
820 while (argc < MAXARGV && (arg = token[6+argc]) != NULL)
821 sep->se_argv[argc++] = xstrdup(arg);
822 /* Some inetd.conf files have no argv's, not even argv[0].
823 * Fix them up.
824 * (Technically, programs can be execed with argv[0] = NULL,
825 * but many programs do not like that at all) */
826 if (argc == 0)
827 sep->se_argv[0] = xstrdup(sep->se_program);
828
829 /* catch mixups. "<service> stream udp ..." == wtf */
830 if (sep->se_socktype == SOCK_STREAM) {
831 if (sep->se_proto_no == IPPROTO_UDP)
832 goto parse_err;
833 }
834 if (sep->se_socktype == SOCK_DGRAM) {
835 if (sep->se_proto_no == IPPROTO_TCP)
836 goto parse_err;
837 }
838
839 //bb_error_msg(
840 // "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
841 // sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
842 // sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
843
844 /* check if the hostname specifier is a comma separated list
845 * of hostnames. we'll make new entries for each address. */
846 while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
847 nsep = dup_servtab(sep);
848 /* NUL terminate the hostname field of the existing entry,
849 * and make a dup for the new entry. */
850 *hostdelim++ = '\0';
851 nsep->se_local_hostname = xstrdup(hostdelim);
852 nsep->se_next = sep->se_next;
853 sep->se_next = nsep;
854 }
855
856 /* was doing it here: */
857 /* DNS resolution, create copies for each IP address */
858 /* IPv6-ization destroyed it :( */
859
860 return sep;
861}
862
863static servtab_t *insert_in_servlist(servtab_t *cp)
864{
865 servtab_t *sep;
866 sigset_t omask;
867
868 sep = new_servtab();
869 *sep = *cp; /* struct copy */
870 sep->se_fd = -1;
871#if ENABLE_FEATURE_INETD_RPC
872 sep->se_rpcprog = -1;
873#endif
874 block_CHLD_HUP_ALRM(&omask);
875 sep->se_next = serv_list;
876 serv_list = sep;
877 restore_sigmask(&omask);
878 return sep;
879}
880
881static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
882{
883 if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
884 return 0;
885 if (strcmp(old->se_service, new->se_service) != 0)
886 return 0;
887 if (strcmp(old->se_proto, new->se_proto) != 0)
888 return 0;
889 return 1;
890}
891
892static void reread_config_file(int sig UNUSED_PARAM)
893{
894 servtab_t *sep, *cp, **sepp;
895 len_and_sockaddr *lsa;
896 sigset_t omask;
897 unsigned n;
898 uint16_t port;
899 int save_errno = errno;
900
901 if (!reopen_config_file())
902 goto ret;
903 for (sep = serv_list; sep; sep = sep->se_next)
904 sep->se_checked = 0;
905
906 goto first_line;
907 while (1) {
908 if (cp == NULL) {
909 first_line:
910 cp = parse_one_line();
911 if (cp == NULL)
912 break;
913 }
914 for (sep = serv_list; sep; sep = sep->se_next)
915 if (same_serv_addr_proto(sep, cp))
916 goto equal_servtab;
917 /* not an "equal" servtab */
918 sep = insert_in_servlist(cp);
919 goto after_check;
920 equal_servtab:
921 {
922 int i;
923
924 block_CHLD_HUP_ALRM(&omask);
925#if ENABLE_FEATURE_INETD_RPC
926 if (is_rpc_service(sep))
927 unregister_rpc(sep);
928 sep->se_rpcver_lo = cp->se_rpcver_lo;
929 sep->se_rpcver_hi = cp->se_rpcver_hi;
930#endif
931 if (cp->se_wait == 0) {
932 /* New config says "nowait". If old one
933 * was "wait", we currently may be waiting
934 * for a child (and not accepting connects).
935 * Stop waiting, start listening again.
936 * (if it's not true, this op is harmless) */
937 add_fd_to_set(sep->se_fd);
938 }
939 sep->se_wait = cp->se_wait;
940 sep->se_max = cp->se_max;
941 /* string fields need more love - we don't want to leak them */
942#define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
943 SWAP(char*, sep->se_user, cp->se_user);
944 SWAP(char*, sep->se_group, cp->se_group);
945 SWAP(char*, sep->se_program, cp->se_program);
946 for (i = 0; i < MAXARGV; i++)
947 SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
948#undef SWAP
949 restore_sigmask(&omask);
950 free_servtab_strings(cp);
951 }
952 after_check:
953 /* cp->string_fields are consumed by insert_in_servlist()
954 * or freed at this point, cp itself is not yet freed. */
955 sep->se_checked = 1;
956
957 /* create new len_and_sockaddr */
958 switch (sep->se_family) {
959 struct sockaddr_un *sun;
960 case AF_UNIX:
961 lsa = xzalloc_lsa(AF_UNIX);
962 sun = (struct sockaddr_un*)&lsa->u.sa;
963 safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
964 break;
965
966 default: /* case AF_INET, case AF_INET6 */
967 n = bb_strtou(sep->se_service, NULL, 10);
968#if ENABLE_FEATURE_INETD_RPC
969 if (is_rpc_service(sep)) {
970 sep->se_rpcprog = n;
971 if (errno) { /* se_service is not numeric */
972 struct rpcent *rp = getrpcbyname(sep->se_service);
973 if (rp == NULL) {
974 bb_error_msg("%s: unknown rpc service", sep->se_service);
975 goto next_cp;
976 }
977 sep->se_rpcprog = rp->r_number;
978 }
979 if (sep->se_fd == -1)
980 prepare_socket_fd(sep);
981 if (sep->se_fd != -1)
982 register_rpc(sep);
983 goto next_cp;
984 }
985#endif
986 /* what port to listen on? */
987 port = htons(n);
988 if (errno || n > 0xffff) { /* se_service is not numeric */
989 char protoname[4];
990 struct servent *sp;
991 /* can result only in "tcp" or "udp": */
992 safe_strncpy(protoname, sep->se_proto, 4);
993 sp = getservbyname(sep->se_service, protoname);
994 if (sp == NULL) {
995 bb_error_msg("%s/%s: unknown service",
996 sep->se_service, sep->se_proto);
997 goto next_cp;
998 }
999 port = sp->s_port;
1000 }
1001 if (LONE_CHAR(sep->se_local_hostname, '*')) {
1002 lsa = xzalloc_lsa(sep->se_family);
1003 set_nport(&lsa->u.sa, port);
1004 } else {
1005 lsa = host_and_af2sockaddr(sep->se_local_hostname,
1006 ntohs(port), sep->se_family);
1007 if (!lsa) {
1008 bb_error_msg("%s/%s: unknown host '%s'",
1009 sep->se_service, sep->se_proto,
1010 sep->se_local_hostname);
1011 goto next_cp;
1012 }
1013 }
1014 break;
1015 } /* end of "switch (sep->se_family)" */
1016
1017 /* did lsa change? Then close/open */
1018 if (sep->se_lsa == NULL
1019 || lsa->len != sep->se_lsa->len
1020 || memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
1021 ) {
1022 remove_fd_from_set(sep->se_fd);
1023 maybe_close(sep->se_fd);
1024 free(sep->se_lsa);
1025 sep->se_lsa = lsa;
1026 sep->se_fd = -1;
1027 } else {
1028 free(lsa);
1029 }
1030 if (sep->se_fd == -1)
1031 prepare_socket_fd(sep);
1032 next_cp:
1033 sep = cp->se_next;
1034 free(cp);
1035 cp = sep;
1036 } /* end of "while (1) parse lines" */
1037 close_config_file();
1038
1039 /* Purge anything not looked at above - these are stale entries,
1040 * new config file doesnt have them. */
1041 block_CHLD_HUP_ALRM(&omask);
1042 sepp = &serv_list;
1043 while ((sep = *sepp) != NULL) {
1044 if (sep->se_checked) {
1045 sepp = &sep->se_next;
1046 continue;
1047 }
1048 *sepp = sep->se_next;
1049 remove_fd_from_set(sep->se_fd);
1050 maybe_close(sep->se_fd);
1051#if ENABLE_FEATURE_INETD_RPC
1052 if (is_rpc_service(sep))
1053 unregister_rpc(sep);
1054#endif
1055 if (sep->se_family == AF_UNIX)
1056 unlink(sep->se_service);
1057 free_servtab_strings(sep);
1058 free(sep);
1059 }
1060 restore_sigmask(&omask);
1061 ret:
1062 errno = save_errno;
1063}
1064
1065static void reap_child(int sig UNUSED_PARAM)
1066{
1067 pid_t pid;
1068 int status;
1069 servtab_t *sep;
1070 int save_errno = errno;
1071
1072 for (;;) {
1073 pid = wait_any_nohang(&status);
1074 if (pid <= 0)
1075 break;
1076 for (sep = serv_list; sep; sep = sep->se_next) {
1077 if (sep->se_wait != pid)
1078 continue;
1079 /* One of our "wait" services */
1080 if (WIFEXITED(status) && WEXITSTATUS(status))
1081 bb_error_msg("%s: exit status %u",
1082 sep->se_program, WEXITSTATUS(status));
1083 else if (WIFSIGNALED(status))
1084 bb_error_msg("%s: exit signal %u",
1085 sep->se_program, WTERMSIG(status));
1086 sep->se_wait = 1;
1087 add_fd_to_set(sep->se_fd);
1088 break;
1089 }
1090 }
1091 errno = save_errno;
1092}
1093
1094static void retry_network_setup(int sig UNUSED_PARAM)
1095{
1096 int save_errno = errno;
1097 servtab_t *sep;
1098
1099 alarm_armed = 0;
1100 for (sep = serv_list; sep; sep = sep->se_next) {
1101 if (sep->se_fd == -1) {
1102 prepare_socket_fd(sep);
1103#if ENABLE_FEATURE_INETD_RPC
1104 if (sep->se_fd != -1 && is_rpc_service(sep))
1105 register_rpc(sep);
1106#endif
1107 }
1108 }
1109 errno = save_errno;
1110}
1111
1112static void clean_up_and_exit(int sig UNUSED_PARAM)
1113{
1114 servtab_t *sep;
1115
1116 /* XXX signal race walking sep list */
1117 for (sep = serv_list; sep; sep = sep->se_next) {
1118 if (sep->se_fd == -1)
1119 continue;
1120
1121 switch (sep->se_family) {
1122 case AF_UNIX:
1123 unlink(sep->se_service);
1124 break;
1125 default: /* case AF_INET, AF_INET6 */
1126#if ENABLE_FEATURE_INETD_RPC
1127 if (sep->se_wait == 1 && is_rpc_service(sep))
1128 unregister_rpc(sep); /* XXX signal race */
1129#endif
1130 break;
1131 }
1132 if (ENABLE_FEATURE_CLEAN_UP)
1133 close(sep->se_fd);
1134 }
1135 remove_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
1136 exit(EXIT_SUCCESS);
1137}
1138
1139int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1140int inetd_main(int argc UNUSED_PARAM, char **argv)
1141{
1142 struct sigaction sa, saved_pipe_handler;
1143 servtab_t *sep, *sep2;
1144 struct passwd *pwd;
1145 struct group *grp = grp; /* for compiler */
1146 int opt;
1147 pid_t pid;
1148 sigset_t omask;
1149
1150 INIT_G();
1151
1152 real_uid = getuid();
1153 if (real_uid != 0) /* run by non-root user */
1154 config_filename = NULL;
1155
1156 opt_complementary = "R+:q+"; /* -q N, -R N */
1157 opt = getopt32(argv, "R:feq:", &max_concurrency, &global_queuelen);
1158 argv += optind;
1159 //argc -= optind;
1160 if (argv[0])
1161 config_filename = argv[0];
1162 if (config_filename == NULL)
1163 bb_error_msg_and_die("non-root must specify config file");
1164 if (!(opt & 2))
1165 bb_daemonize_or_rexec(0, argv - optind);
1166 else
1167 bb_sanitize_stdio();
1168 if (!(opt & 4)) {
1169 /* LOG_NDELAY: connect to syslog daemon NOW.
1170 * Otherwise, we may open syslog socket
1171 * in vforked child, making opened fds and syslog()
1172 * internal state inconsistent.
1173 * This was observed to leak file descriptors. */
1174 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1175 logmode = LOGMODE_SYSLOG;
1176 }
1177
1178 if (real_uid == 0) {
1179 /* run by root, ensure groups vector gets trashed */
1180 gid_t gid = getgid();
1181 setgroups(1, &gid);
1182 }
1183
1184 write_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
1185
1186 /* never fails under Linux (except if you pass it bad arguments) */
1187 getrlimit(RLIMIT_NOFILE, &rlim_ofile);
1188 rlim_ofile_cur = rlim_ofile.rlim_cur;
1189 if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
1190 rlim_ofile_cur = OPEN_MAX;
1191
1192 memset(&sa, 0, sizeof(sa));
1193 /*sigemptyset(&sa.sa_mask); - memset did it */
1194 sigaddset(&sa.sa_mask, SIGALRM);
1195 sigaddset(&sa.sa_mask, SIGCHLD);
1196 sigaddset(&sa.sa_mask, SIGHUP);
1197//FIXME: explain why no SA_RESTART
1198//FIXME: retry_network_setup is unsafe to run in signal handler (many reasons)!
1199 sa.sa_handler = retry_network_setup;
1200 sigaction_set(SIGALRM, &sa);
1201//FIXME: reread_config_file is unsafe to run in signal handler(many reasons)!
1202 sa.sa_handler = reread_config_file;
1203 sigaction_set(SIGHUP, &sa);
1204//FIXME: reap_child is unsafe to run in signal handler (uses stdio)!
1205 sa.sa_handler = reap_child;
1206 sigaction_set(SIGCHLD, &sa);
1207//FIXME: clean_up_and_exit is unsafe to run in signal handler (uses stdio)!
1208 sa.sa_handler = clean_up_and_exit;
1209 sigaction_set(SIGTERM, &sa);
1210 sa.sa_handler = clean_up_and_exit;
1211 sigaction_set(SIGINT, &sa);
1212 sa.sa_handler = SIG_IGN;
1213 sigaction(SIGPIPE, &sa, &saved_pipe_handler);
1214
1215 reread_config_file(SIGHUP); /* load config from file */
1216
1217 for (;;) {
1218 int ready_fd_cnt;
1219 int ctrl, accepted_fd, new_udp_fd;
1220 fd_set readable;
1221
1222 if (maxsock < 0)
1223 recalculate_maxsock();
1224
1225 readable = allsock; /* struct copy */
1226 /* if there are no fds to wait on, we will block
1227 * until signal wakes us up (maxsock == 0, but readable
1228 * never contains fds 0 and 1...) */
1229 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
1230 if (ready_fd_cnt < 0) {
1231 if (errno != EINTR) {
1232 bb_perror_msg("select");
1233 sleep(1);
1234 }
1235 continue;
1236 }
1237 dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
1238
1239 for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
1240 if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1241 continue;
1242
1243 dbg("ready fd:%d\n", sep->se_fd);
1244 ready_fd_cnt--;
1245 ctrl = sep->se_fd;
1246 accepted_fd = -1;
1247 new_udp_fd = -1;
1248 if (!sep->se_wait) {
1249 if (sep->se_socktype == SOCK_STREAM) {
1250 ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
1251 dbg("accepted_fd:%d\n", accepted_fd);
1252 if (ctrl < 0) {
1253 if (errno != EINTR)
1254 bb_perror_msg("accept (for %s)", sep->se_service);
1255 continue;
1256 }
1257 }
1258 /* "nowait" udp */
1259 if (sep->se_socktype == SOCK_DGRAM
1260 && sep->se_family != AF_UNIX
1261 ) {
1262/* How udp "nowait" works:
1263 * child peeks at (received and buffered by kernel) UDP packet,
1264 * performs connect() on the socket so that it is linked only
1265 * to this peer. But this also affects parent, because descriptors
1266 * are shared after fork() a-la dup(). When parent performs
1267 * select(), it will see this descriptor connected to the peer (!)
1268 * and still readable, will act on it and mess things up
1269 * (can create many copies of same child, etc).
1270 * Parent must create and use new socket instead. */
1271 new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
1272 dbg("new_udp_fd:%d\n", new_udp_fd);
1273 if (new_udp_fd < 0) { /* error: eat packet, forget about it */
1274 udp_err:
1275 recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
1276 continue;
1277 }
1278 setsockopt_reuseaddr(new_udp_fd);
1279 /* TODO: better do bind after fork in parent,
1280 * so that we don't have two wildcard bound sockets
1281 * even for a brief moment? */
1282 if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
1283 dbg("bind(new_udp_fd) failed\n");
1284 close(new_udp_fd);
1285 goto udp_err;
1286 }
1287 dbg("bind(new_udp_fd) succeeded\n");
1288 }
1289 }
1290
1291 block_CHLD_HUP_ALRM(&omask);
1292 pid = 0;
1293#ifdef INETD_BUILTINS_ENABLED
1294 /* do we need to fork? */
1295 if (sep->se_builtin == NULL
1296 || (sep->se_socktype == SOCK_STREAM
1297 && sep->se_builtin->bi_fork))
1298#endif
1299 {
1300 if (sep->se_max != 0) {
1301 if (++sep->se_count == 1)
1302 sep->se_time = monotonic_sec();
1303 else if (sep->se_count >= sep->se_max) {
1304 unsigned now = monotonic_sec();
1305 /* did we accumulate se_max connects too quickly? */
1306 if (now - sep->se_time <= CNT_INTERVAL) {
1307 bb_error_msg("%s/%s: too many connections, pausing",
1308 sep->se_service, sep->se_proto);
1309 remove_fd_from_set(sep->se_fd);
1310 close(sep->se_fd);
1311 sep->se_fd = -1;
1312 sep->se_count = 0;
1313 rearm_alarm(); /* will revive it in RETRYTIME sec */
1314 restore_sigmask(&omask);
1315 maybe_close(new_udp_fd);
1316 maybe_close(accepted_fd);
1317 continue; /* -> check next fd in fd set */
1318 }
1319 sep->se_count = 0;
1320 }
1321 }
1322 /* on NOMMU, streamed chargen
1323 * builtin wouldn't work, but it is
1324 * not allowed on NOMMU (ifdefed out) */
1325#ifdef INETD_BUILTINS_ENABLED
1326 if (BB_MMU && sep->se_builtin)
1327 pid = fork();
1328 else
1329#endif
1330 pid = vfork();
1331
1332 if (pid < 0) { /* fork error */
1333 bb_perror_msg("vfork"+1);
1334 sleep(1);
1335 restore_sigmask(&omask);
1336 maybe_close(new_udp_fd);
1337 maybe_close(accepted_fd);
1338 continue; /* -> check next fd in fd set */
1339 }
1340 if (pid == 0)
1341 pid--; /* -1: "we did fork and we are child" */
1342 }
1343 /* if pid == 0 here, we didn't fork */
1344
1345 if (pid > 0) { /* parent */
1346 if (sep->se_wait) {
1347 /* wait: we passed socket to child,
1348 * will wait for child to terminate */
1349 sep->se_wait = pid;
1350 remove_fd_from_set(sep->se_fd);
1351 }
1352 if (new_udp_fd >= 0) {
1353 /* udp nowait: child connected the socket,
1354 * we created and will use new, unconnected one */
1355 xmove_fd(new_udp_fd, sep->se_fd);
1356 dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
1357 }
1358 restore_sigmask(&omask);
1359 maybe_close(accepted_fd);
1360 continue; /* -> check next fd in fd set */
1361 }
1362
1363 /* we are either child or didn't fork at all */
1364#ifdef INETD_BUILTINS_ENABLED
1365 if (sep->se_builtin) {
1366 if (pid) { /* "pid" is -1: we did fork */
1367 close(sep->se_fd); /* listening socket */
1368 dbg("closed sep->se_fd:%d\n", sep->se_fd);
1369 logmode = LOGMODE_NONE; /* make xwrite etc silent */
1370 }
1371 restore_sigmask(&omask);
1372 if (sep->se_socktype == SOCK_STREAM)
1373 sep->se_builtin->bi_stream_fn(ctrl, sep);
1374 else
1375 sep->se_builtin->bi_dgram_fn(ctrl, sep);
1376 if (pid) /* we did fork */
1377 _exit(EXIT_FAILURE);
1378 maybe_close(accepted_fd);
1379 continue; /* -> check next fd in fd set */
1380 }
1381#endif
1382 /* child */
1383 setsid();
1384 /* "nowait" udp */
1385 if (new_udp_fd >= 0) {
1386 len_and_sockaddr *lsa;
1387 int r;
1388
1389 close(new_udp_fd);
1390 dbg("closed new_udp_fd:%d\n", new_udp_fd);
1391 lsa = xzalloc_lsa(sep->se_family);
1392 /* peek at the packet and remember peer addr */
1393 r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
1394 &lsa->u.sa, &lsa->len);
1395 if (r < 0)
1396 goto do_exit1;
1397 /* make this socket "connected" to peer addr:
1398 * only packets from this peer will be recv'ed,
1399 * and bare write()/send() will work on it */
1400 connect(ctrl, &lsa->u.sa, lsa->len);
1401 dbg("connected ctrl:%d to remote peer\n", ctrl);
1402 free(lsa);
1403 }
1404 /* prepare env and exec program */
1405 pwd = getpwnam(sep->se_user);
1406 if (pwd == NULL) {
1407 bb_error_msg("%s: no such %s", sep->se_user, "user");
1408 goto do_exit1;
1409 }
1410 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1411 bb_error_msg("%s: no such %s", sep->se_group, "group");
1412 goto do_exit1;
1413 }
1414 if (real_uid != 0 && real_uid != pwd->pw_uid) {
1415 /* a user running private inetd */
1416 bb_error_msg("non-root must run services as himself");
1417 goto do_exit1;
1418 }
1419 if (pwd->pw_uid != 0) {
1420 if (sep->se_group)
1421 pwd->pw_gid = grp->gr_gid;
1422 /* initgroups, setgid, setuid: */
1423 change_identity(pwd);
1424 } else if (sep->se_group) {
1425 xsetgid(grp->gr_gid);
1426 setgroups(1, &grp->gr_gid);
1427 }
1428 if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1429 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1430 bb_perror_msg("setrlimit");
1431
1432 /* closelog(); - WRONG. we are after vfork,
1433 * this may confuse syslog() internal state.
1434 * Let's hope libc sets syslog fd to CLOEXEC...
1435 */
1436 xmove_fd(ctrl, STDIN_FILENO);
1437 xdup2(STDIN_FILENO, STDOUT_FILENO);
1438 dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
1439 /* manpages of inetd I managed to find either say
1440 * that stderr is also redirected to the network,
1441 * or do not talk about redirection at all (!) */
1442 if (!sep->se_wait) /* only for usual "tcp nowait" */
1443 xdup2(STDIN_FILENO, STDERR_FILENO);
1444 /* NB: among others, this loop closes listening sockets
1445 * for nowait stream children */
1446 for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
1447 if (sep2->se_fd != ctrl)
1448 maybe_close(sep2->se_fd);
1449 sigaction_set(SIGPIPE, &saved_pipe_handler);
1450 restore_sigmask(&omask);
1451 dbg("execing:'%s'\n", sep->se_program);
1452 BB_EXECVP(sep->se_program, sep->se_argv);
1453 bb_perror_msg("can't execute '%s'", sep->se_program);
1454 do_exit1:
1455 /* eat packet in udp case */
1456 if (sep->se_socktype != SOCK_STREAM)
1457 recv(0, line, LINE_SIZE, MSG_DONTWAIT);
1458 _exit(EXIT_FAILURE);
1459 } /* for (sep = servtab...) */
1460 } /* for (;;) */
1461}
1462
1463#if !BB_MMU
1464static const char *const cat_args[] = { "cat", NULL };
1465#endif
1466
1467/*
1468 * Internet services provided internally by inetd:
1469 */
1470#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1471/* Echo service -- echo data back. */
1472/* ARGSUSED */
1473static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
1474{
1475#if BB_MMU
1476 while (1) {
1477 ssize_t sz = safe_read(s, line, LINE_SIZE);
1478 if (sz <= 0)
1479 break;
1480 xwrite(s, line, sz);
1481 }
1482#else
1483 /* We are after vfork here! */
1484 /* move network socket to stdin/stdout */
1485 xmove_fd(s, STDIN_FILENO);
1486 xdup2(STDIN_FILENO, STDOUT_FILENO);
1487 /* no error messages please... */
1488 close(STDERR_FILENO);
1489 xopen(bb_dev_null, O_WRONLY);
1490 BB_EXECVP("cat", (char**)cat_args);
1491 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1492#endif
1493}
1494static void FAST_FUNC echo_dg(int s, servtab_t *sep)
1495{
1496 enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
1497 char *buf = xmalloc(BUFSIZE); /* too big for stack */
1498 int sz;
1499 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1500
1501 lsa->len = sep->se_lsa->len;
1502 /* dgram builtins are non-forking - DONT BLOCK! */
1503 sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
1504 if (sz > 0)
1505 sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
1506 free(buf);
1507}
1508#endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1509
1510
1511#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1512/* Discard service -- ignore data. */
1513/* ARGSUSED */
1514static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
1515{
1516#if BB_MMU
1517 while (safe_read(s, line, LINE_SIZE) > 0)
1518 continue;
1519#else
1520 /* We are after vfork here! */
1521 /* move network socket to stdin */
1522 xmove_fd(s, STDIN_FILENO);
1523 /* discard output */
1524 close(STDOUT_FILENO);
1525 xopen(bb_dev_null, O_WRONLY);
1526 /* no error messages please... */
1527 xdup2(STDOUT_FILENO, STDERR_FILENO);
1528 BB_EXECVP("cat", (char**)cat_args);
1529 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1530#endif
1531}
1532/* ARGSUSED */
1533static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
1534{
1535 /* dgram builtins are non-forking - DONT BLOCK! */
1536 recv(s, line, LINE_SIZE, MSG_DONTWAIT);
1537}
1538#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1539
1540
1541#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1542#define LINESIZ 72
1543static void init_ring(void)
1544{
1545 int i;
1546
1547 end_ring = ring;
1548 for (i = ' '; i < 127; i++)
1549 *end_ring++ = i;
1550}
1551/* Character generator. MMU arches only. */
1552/* ARGSUSED */
1553static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
1554{
1555 char *rs;
1556 int len;
1557 char text[LINESIZ + 2];
1558
1559 if (!end_ring) {
1560 init_ring();
1561 rs = ring;
1562 }
1563
1564 text[LINESIZ] = '\r';
1565 text[LINESIZ + 1] = '\n';
1566 rs = ring;
1567 for (;;) {
1568 len = end_ring - rs;
1569 if (len >= LINESIZ)
1570 memmove(text, rs, LINESIZ);
1571 else {
1572 memmove(text, rs, len);
1573 memmove(text + len, ring, LINESIZ - len);
1574 }
1575 if (++rs == end_ring)
1576 rs = ring;
1577 xwrite(s, text, sizeof(text));
1578 }
1579}
1580/* ARGSUSED */
1581static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
1582{
1583 int len;
1584 char text[LINESIZ + 2];
1585 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1586
1587 /* Eat UDP packet which started it all */
1588 /* dgram builtins are non-forking - DONT BLOCK! */
1589 lsa->len = sep->se_lsa->len;
1590 if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1591 return;
1592
1593 if (!end_ring) {
1594 init_ring();
1595 ring_pos = ring;
1596 }
1597
1598 len = end_ring - ring_pos;
1599 if (len >= LINESIZ)
1600 memmove(text, ring_pos, LINESIZ);
1601 else {
1602 memmove(text, ring_pos, len);
1603 memmove(text + len, ring, LINESIZ - len);
1604 }
1605 if (++ring_pos == end_ring)
1606 ring_pos = ring;
1607 text[LINESIZ] = '\r';
1608 text[LINESIZ + 1] = '\n';
1609 sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
1610}
1611#endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1612
1613
1614#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1615/*
1616 * Return a machine readable date and time, in the form of the
1617 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
1618 * returns the number of seconds since midnight, Jan 1, 1970,
1619 * we must add 2208988800 seconds to this figure to make up for
1620 * some seventy years Bell Labs was asleep.
1621 */
1622static uint32_t machtime(void)
1623{
1624 struct timeval tv;
1625
1626 gettimeofday(&tv, NULL);
1627 return htonl((uint32_t)(tv.tv_sec + 2208988800));
1628}
1629/* ARGSUSED */
1630static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
1631{
1632 uint32_t result;
1633
1634 result = machtime();
1635 full_write(s, &result, sizeof(result));
1636}
1637static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
1638{
1639 uint32_t result;
1640 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1641
1642 lsa->len = sep->se_lsa->len;
1643 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1644 return;
1645
1646 result = machtime();
1647 sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
1648}
1649#endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1650
1651
1652#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1653/* Return human-readable time of day */
1654/* ARGSUSED */
1655static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
1656{
1657 time_t t;
1658
1659 time(&t);
1660 fdprintf(s, "%.24s\r\n", ctime(&t));
1661}
1662static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
1663{
1664 time_t t;
1665 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1666
1667 lsa->len = sep->se_lsa->len;
1668 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1669 return;
1670
1671 t = time(NULL);
1672 sprintf(line, "%.24s\r\n", ctime(&t));
1673 sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
1674}
1675#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
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