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Merge branch 'Teaman-ND' into Teaman-RT
[tomato.git] / release / src / router / busybox / networking / inetd.c
blobfb00c6cd71e8df10d42ba7ee643c5d8078672d96
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 #include <syslog.h>
158 #include <sys/un.h>
159
160 #include "libbb.h"
161
162 #if ENABLE_FEATURE_INETD_RPC
163 #include <rpc/rpc.h>
164 #include <rpc/pmap_clnt.h>
165 #endif
166
167 #if !BB_MMU
168 /* stream version of chargen is forking but not execing,
169 * can't do that (easily) on NOMMU */
170 #undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
171 #define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
172 #endif
173
174 #define _PATH_INETDPID "/var/run/inetd.pid"
175
176 #define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
177 #define RETRYTIME 60 /* retry after bind or server fail */
178
179 // TODO: explain, or get rid of setrlimit games
180
181 #ifndef RLIMIT_NOFILE
182 #define RLIMIT_NOFILE RLIMIT_OFILE
183 #endif
184
185 #ifndef OPEN_MAX
186 #define OPEN_MAX 64
187 #endif
188
189 /* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
190 #define FD_MARGIN 8
191
192 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
193 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
194 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
195 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
196 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
197 # define INETD_BUILTINS_ENABLED
198 #endif
199
200 typedef struct servtab_t {
201 /* The most frequently referenced one: */
202 int se_fd; /* open descriptor */
203 /* NB: 'biggest fields last' saves on code size (~250 bytes) */
204 /* [addr:]service socktype proto wait user[:group] prog [args] */
205 char *se_local_hostname; /* addr to listen on */
206 char *se_service; /* "80" or "www" or "mount/2[-3]" */
207 /* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
208 char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
209 #if ENABLE_FEATURE_INETD_RPC
210 int se_rpcprog; /* rpc program number */
211 int se_rpcver_lo; /* rpc program lowest version */
212 int se_rpcver_hi; /* rpc program highest version */
213 #define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
214 #else
215 #define is_rpc_service(sep) 0
216 #endif
217 pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
218 /* and waiting for this pid */
219 socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
220 family_t se_family; /* AF_UNIX/INET[6] */
221 /* se_proto_no is used by RPC code only... hmm */
222 smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
223 smallint se_checked; /* looked at during merge */
224 unsigned se_max; /* allowed instances per minute */
225 unsigned se_count; /* number started since se_time */
226 unsigned se_time; /* when we started counting */
227 char *se_user; /* user name to run as */
228 char *se_group; /* group name to run as, can be NULL */
229 #ifdef INETD_BUILTINS_ENABLED
230 const struct builtin *se_builtin; /* if built-in, description */
231 #endif
232 struct servtab_t *se_next;
233 len_and_sockaddr *se_lsa;
234 char *se_program; /* server program */
235 #define MAXARGV 20
236 char *se_argv[MAXARGV + 1]; /* program arguments */
237 } servtab_t;
238
239 #ifdef INETD_BUILTINS_ENABLED
240 /* Echo received data */
241 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
242 static void FAST_FUNC echo_stream(int, servtab_t *);
243 static void FAST_FUNC echo_dg(int, servtab_t *);
244 #endif
245 /* Internet /dev/null */
246 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
247 static void FAST_FUNC discard_stream(int, servtab_t *);
248 static void FAST_FUNC discard_dg(int, servtab_t *);
249 #endif
250 /* Return 32 bit time since 1900 */
251 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
252 static void FAST_FUNC machtime_stream(int, servtab_t *);
253 static void FAST_FUNC machtime_dg(int, servtab_t *);
254 #endif
255 /* Return human-readable time */
256 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
257 static void FAST_FUNC daytime_stream(int, servtab_t *);
258 static void FAST_FUNC daytime_dg(int, servtab_t *);
259 #endif
260 /* Familiar character generator */
261 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
262 static void FAST_FUNC chargen_stream(int, servtab_t *);
263 static void FAST_FUNC chargen_dg(int, servtab_t *);
264 #endif
265
266 struct builtin {
267 /* NB: not necessarily NUL terminated */
268 char bi_service7[7]; /* internally provided service name */
269 uint8_t bi_fork; /* 1 if stream fn should run in child */
270 void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
271 void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
272 };
273
274 static const struct builtin builtins[] = {
275 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
276 { "echo", 1, echo_stream, echo_dg },
277 #endif
278 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
279 { "discard", 1, discard_stream, discard_dg },
280 #endif
281 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
282 { "chargen", 1, chargen_stream, chargen_dg },
283 #endif
284 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
285 { "time", 0, machtime_stream, machtime_dg },
286 #endif
287 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
288 { "daytime", 0, daytime_stream, daytime_dg },
289 #endif
290 };
291 #endif /* INETD_BUILTINS_ENABLED */
292
293 struct globals {
294 rlim_t rlim_ofile_cur;
295 struct rlimit rlim_ofile;
296 servtab_t *serv_list;
297 int global_queuelen;
298 int maxsock; /* max fd# in allsock, -1: unknown */
299 /* whenever maxsock grows, prev_maxsock is set to new maxsock,
300 * but if maxsock is set to -1, prev_maxsock is not changed */
301 int prev_maxsock;
302 unsigned max_concurrency;
303 smallint alarm_armed;
304 uid_t real_uid; /* user ID who ran us */
305 const char *config_filename;
306 parser_t *parser;
307 char *default_local_hostname;
308 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
309 char *end_ring;
310 char *ring_pos;
311 char ring[128];
312 #endif
313 fd_set allsock;
314 /* Used in next_line(), and as scratch read buffer */
315 char line[256]; /* _at least_ 256, see LINE_SIZE */
316 } FIX_ALIASING;
317 #define G (*(struct globals*)&bb_common_bufsiz1)
318 enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
319 struct BUG_G_too_big {
320 char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
321 };
322 #define rlim_ofile_cur (G.rlim_ofile_cur )
323 #define rlim_ofile (G.rlim_ofile )
324 #define serv_list (G.serv_list )
325 #define global_queuelen (G.global_queuelen)
326 #define maxsock (G.maxsock )
327 #define prev_maxsock (G.prev_maxsock )
328 #define max_concurrency (G.max_concurrency)
329 #define alarm_armed (G.alarm_armed )
330 #define real_uid (G.real_uid )
331 #define config_filename (G.config_filename)
332 #define parser (G.parser )
333 #define default_local_hostname (G.default_local_hostname)
334 #define first_ps_byte (G.first_ps_byte )
335 #define last_ps_byte (G.last_ps_byte )
336 #define end_ring (G.end_ring )
337 #define ring_pos (G.ring_pos )
338 #define ring (G.ring )
339 #define allsock (G.allsock )
340 #define line (G.line )
341 #define INIT_G() do { \
342 rlim_ofile_cur = OPEN_MAX; \
343 global_queuelen = 128; \
344 config_filename = "/etc/inetd.conf"; \
345 } while (0)
346
347 static void maybe_close(int fd)
348 {
349 if (fd >= 0)
350 close(fd);
351 }
352
353 // TODO: move to libbb?
354 static len_and_sockaddr *xzalloc_lsa(int family)
355 {
356 len_and_sockaddr *lsa;
357 int sz;
358
359 sz = sizeof(struct sockaddr_in);
360 if (family == AF_UNIX)
361 sz = sizeof(struct sockaddr_un);
362 #if ENABLE_FEATURE_IPV6
363 if (family == AF_INET6)
364 sz = sizeof(struct sockaddr_in6);
365 #endif
366 lsa = xzalloc(LSA_LEN_SIZE + sz);
367 lsa->len = sz;
368 lsa->u.sa.sa_family = family;
369 return lsa;
370 }
371
372 static void rearm_alarm(void)
373 {
374 if (!alarm_armed) {
375 alarm_armed = 1;
376 alarm(RETRYTIME);
377 }
378 }
379
380 static void block_CHLD_HUP_ALRM(sigset_t *m)
381 {
382 sigemptyset(m);
383 sigaddset(m, SIGCHLD);
384 sigaddset(m, SIGHUP);
385 sigaddset(m, SIGALRM);
386 sigprocmask(SIG_BLOCK, m, m); /* old sigmask is stored in m */
387 }
388
389 static void restore_sigmask(sigset_t *m)
390 {
391 sigprocmask(SIG_SETMASK, m, NULL);
392 }
393
394 #if ENABLE_FEATURE_INETD_RPC
395 static void register_rpc(servtab_t *sep)
396 {
397 int n;
398 struct sockaddr_in ir_sin;
399 socklen_t size;
400
401 size = sizeof(ir_sin);
402 if (getsockname(sep->se_fd, (struct sockaddr *) &ir_sin, &size) < 0) {
403 bb_perror_msg("getsockname");
404 return;
405 }
406
407 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
408 pmap_unset(sep->se_rpcprog, n);
409 if (!pmap_set(sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port)))
410 bb_perror_msg("%s %s: pmap_set(%u,%u,%u,%u)",
411 sep->se_service, sep->se_proto,
412 sep->se_rpcprog, n, sep->se_proto_no, ntohs(ir_sin.sin_port));
413 }
414 }
415
416 static void unregister_rpc(servtab_t *sep)
417 {
418 int n;
419
420 for (n = sep->se_rpcver_lo; n <= sep->se_rpcver_hi; n++) {
421 if (!pmap_unset(sep->se_rpcprog, n))
422 bb_perror_msg("pmap_unset(%u,%u)", sep->se_rpcprog, n);
423 }
424 }
425 #endif /* FEATURE_INETD_RPC */
426
427 static void bump_nofile(void)
428 {
429 enum { FD_CHUNK = 32 };
430 struct rlimit rl;
431
432 /* Never fails under Linux (except if you pass it bad arguments) */
433 getrlimit(RLIMIT_NOFILE, &rl);
434 rl.rlim_cur = MIN(rl.rlim_max, rl.rlim_cur + FD_CHUNK);
435 rl.rlim_cur = MIN(FD_SETSIZE, rl.rlim_cur + FD_CHUNK);
436 if (rl.rlim_cur <= rlim_ofile_cur) {
437 bb_error_msg("can't extend file limit, max = %d",
438 (int) rl.rlim_cur);
439 return;
440 }
441
442 if (setrlimit(RLIMIT_NOFILE, &rl) < 0) {
443 bb_perror_msg("setrlimit");
444 return;
445 }
446
447 rlim_ofile_cur = rl.rlim_cur;
448 }
449
450 static void remove_fd_from_set(int fd)
451 {
452 if (fd >= 0) {
453 FD_CLR(fd, &allsock);
454 maxsock = -1;
455 }
456 }
457
458 static void add_fd_to_set(int fd)
459 {
460 if (fd >= 0) {
461 FD_SET(fd, &allsock);
462 if (maxsock >= 0 && fd > maxsock) {
463 prev_maxsock = maxsock = fd;
464 if ((rlim_t)fd > rlim_ofile_cur - FD_MARGIN)
465 bump_nofile();
466 }
467 }
468 }
469
470 static void recalculate_maxsock(void)
471 {
472 int fd = 0;
473
474 /* We may have no services, in this case maxsock should still be >= 0
475 * (code elsewhere is not happy with maxsock == -1) */
476 maxsock = 0;
477 while (fd <= prev_maxsock) {
478 if (FD_ISSET(fd, &allsock))
479 maxsock = fd;
480 fd++;
481 }
482 prev_maxsock = maxsock;
483 if ((rlim_t)maxsock > rlim_ofile_cur - FD_MARGIN)
484 bump_nofile();
485 }
486
487 static void prepare_socket_fd(servtab_t *sep)
488 {
489 int r, fd;
490
491 fd = socket(sep->se_family, sep->se_socktype, 0);
492 if (fd < 0) {
493 bb_perror_msg("socket");
494 return;
495 }
496 setsockopt_reuseaddr(fd);
497
498 #if ENABLE_FEATURE_INETD_RPC
499 if (is_rpc_service(sep)) {
500 struct passwd *pwd;
501
502 /* zero out the port for all RPC services; let bind()
503 * find one. */
504 set_nport(sep->se_lsa, 0);
505
506 /* for RPC services, attempt to use a reserved port
507 * if they are going to be running as root. */
508 if (real_uid == 0 && sep->se_family == AF_INET
509 && (pwd = getpwnam(sep->se_user)) != NULL
510 && pwd->pw_uid == 0
511 ) {
512 r = bindresvport(fd, &sep->se_lsa->u.sin);
513 } else {
514 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
515 }
516 if (r == 0) {
517 int saveerrno = errno;
518 /* update lsa with port# */
519 getsockname(fd, &sep->se_lsa->u.sa, &sep->se_lsa->len);
520 errno = saveerrno;
521 }
522 } else
523 #endif
524 {
525 if (sep->se_family == AF_UNIX) {
526 struct sockaddr_un *sun;
527 sun = (struct sockaddr_un*)&(sep->se_lsa->u.sa);
528 unlink(sun->sun_path);
529 }
530 r = bind(fd, &sep->se_lsa->u.sa, sep->se_lsa->len);
531 }
532 if (r < 0) {
533 bb_perror_msg("%s/%s: bind",
534 sep->se_service, sep->se_proto);
535 close(fd);
536 rearm_alarm();
537 return;
538 }
539 if (sep->se_socktype == SOCK_STREAM)
540 listen(fd, global_queuelen);
541
542 add_fd_to_set(fd);
543 sep->se_fd = fd;
544 }
545
546 static int reopen_config_file(void)
547 {
548 free(default_local_hostname);
549 default_local_hostname = xstrdup("*");
550 if (parser != NULL)
551 config_close(parser);
552 parser = config_open(config_filename);
553 return (parser != NULL);
554 }
555
556 static void close_config_file(void)
557 {
558 if (parser) {
559 config_close(parser);
560 parser = NULL;
561 }
562 }
563
564 static void free_servtab_strings(servtab_t *cp)
565 {
566 int i;
567
568 free(cp->se_local_hostname);
569 free(cp->se_service);
570 free(cp->se_proto);
571 free(cp->se_user);
572 free(cp->se_group);
573 free(cp->se_lsa); /* not a string in fact */
574 free(cp->se_program);
575 for (i = 0; i < MAXARGV; i++)
576 free(cp->se_argv[i]);
577 }
578
579 static servtab_t *new_servtab(void)
580 {
581 servtab_t *newtab = xzalloc(sizeof(servtab_t));
582 newtab->se_fd = -1; /* paranoia */
583 return newtab;
584 }
585
586 static servtab_t *dup_servtab(servtab_t *sep)
587 {
588 servtab_t *newtab;
589 int argc;
590
591 newtab = new_servtab();
592 *newtab = *sep; /* struct copy */
593 /* deep-copying strings */
594 newtab->se_service = xstrdup(newtab->se_service);
595 newtab->se_proto = xstrdup(newtab->se_proto);
596 newtab->se_user = xstrdup(newtab->se_user);
597 newtab->se_group = xstrdup(newtab->se_group);
598 newtab->se_program = xstrdup(newtab->se_program);
599 for (argc = 0; argc <= MAXARGV; argc++)
600 newtab->se_argv[argc] = xstrdup(newtab->se_argv[argc]);
601 /* NB: se_fd, se_hostaddr and se_next are always
602 * overwrittend by callers, so we don't bother resetting them
603 * to NULL/0/-1 etc */
604
605 return newtab;
606 }
607
608 /* gcc generates much more code if this is inlined */
609 static servtab_t *parse_one_line(void)
610 {
611 int argc;
612 char *token[6+MAXARGV];
613 char *p, *arg;
614 char *hostdelim;
615 servtab_t *sep;
616 servtab_t *nsep;
617 new:
618 sep = new_servtab();
619 more:
620 argc = config_read(parser, token, 6+MAXARGV, 1, "# \t", PARSE_NORMAL);
621 if (!argc) {
622 free(sep);
623 return NULL;
624 }
625
626 /* [host:]service socktype proto wait user[:group] prog [args] */
627 /* Check for "host:...." line */
628 arg = token[0];
629 hostdelim = strrchr(arg, ':');
630 if (hostdelim) {
631 *hostdelim = '\0';
632 sep->se_local_hostname = xstrdup(arg);
633 arg = hostdelim + 1;
634 if (*arg == '\0' && argc == 1) {
635 /* Line has just "host:", change the
636 * default host for the following lines. */
637 free(default_local_hostname);
638 default_local_hostname = sep->se_local_hostname;
639 goto more;
640 }
641 } else
642 sep->se_local_hostname = xstrdup(default_local_hostname);
643
644 /* service socktype proto wait user[:group] prog [args] */
645 sep->se_service = xstrdup(arg);
646
647 /* socktype proto wait user[:group] prog [args] */
648 if (argc < 6) {
649 parse_err:
650 bb_error_msg("parse error on line %u, line is ignored",
651 parser->lineno);
652 free_servtab_strings(sep);
653 /* Just "goto more" can make sep to carry over e.g.
654 * "rpc"-ness (by having se_rpcver_lo != 0).
655 * We will be more paranoid: */
656 free(sep);
657 goto new;
658 }
659
660 {
661 static const int8_t SOCK_xxx[] ALIGN1 = {
662 -1,
663 SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
664 SOCK_SEQPACKET, SOCK_RAW
665 };
666 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
667 "stream""\0" "dgram""\0" "rdm""\0"
668 "seqpacket""\0" "raw""\0"
669 , token[1])];
670 }
671
672 /* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
673 sep->se_proto = arg = xstrdup(token[2]);
674 if (strcmp(arg, "unix") == 0) {
675 sep->se_family = AF_UNIX;
676 } else {
677 char *six;
678 sep->se_family = AF_INET;
679 six = last_char_is(arg, '6');
680 if (six) {
681 #if ENABLE_FEATURE_IPV6
682 *six = '\0';
683 sep->se_family = AF_INET6;
684 #else
685 bb_error_msg("%s: no support for IPv6", sep->se_proto);
686 goto parse_err;
687 #endif
688 }
689 if (strncmp(arg, "rpc/", 4) == 0) {
690 #if ENABLE_FEATURE_INETD_RPC
691 unsigned n;
692 arg += 4;
693 p = strchr(sep->se_service, '/');
694 if (p == NULL) {
695 bb_error_msg("no rpc version: '%s'", sep->se_service);
696 goto parse_err;
697 }
698 *p++ = '\0';
699 n = bb_strtou(p, &p, 10);
700 if (n > INT_MAX) {
701 bad_ver_spec:
702 bb_error_msg("bad rpc version");
703 goto parse_err;
704 }
705 sep->se_rpcver_lo = sep->se_rpcver_hi = n;
706 if (*p == '-') {
707 p++;
708 n = bb_strtou(p, &p, 10);
709 if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
710 goto bad_ver_spec;
711 sep->se_rpcver_hi = n;
712 }
713 if (*p != '\0')
714 goto bad_ver_spec;
715 #else
716 bb_error_msg("no support for rpc services");
717 goto parse_err;
718 #endif
719 }
720 /* we don't really need getprotobyname()! */
721 if (strcmp(arg, "tcp") == 0)
722 sep->se_proto_no = IPPROTO_TCP; /* = 6 */
723 if (strcmp(arg, "udp") == 0)
724 sep->se_proto_no = IPPROTO_UDP; /* = 17 */
725 if (six)
726 *six = '6';
727 if (!sep->se_proto_no) /* not tcp/udp?? */
728 goto parse_err;
729 }
730
731 /* [no]wait[.max] user[:group] prog [args] */
732 arg = token[3];
733 sep->se_max = max_concurrency;
734 p = strchr(arg, '.');
735 if (p) {
736 *p++ = '\0';
737 sep->se_max = bb_strtou(p, NULL, 10);
738 if (errno)
739 goto parse_err;
740 }
741 sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
742 if (!sep->se_wait) /* "no" seen */
743 arg += 2;
744 if (strcmp(arg, "wait") != 0)
745 goto parse_err;
746
747 /* user[:group] prog [args] */
748 sep->se_user = xstrdup(token[4]);
749 arg = strchr(sep->se_user, '.');
750 if (arg == NULL)
751 arg = strchr(sep->se_user, ':');
752 if (arg) {
753 *arg++ = '\0';
754 sep->se_group = xstrdup(arg);
755 }
756
757 /* prog [args] */
758 sep->se_program = xstrdup(token[5]);
759 #ifdef INETD_BUILTINS_ENABLED
760 if (strcmp(sep->se_program, "internal") == 0
761 && strlen(sep->se_service) <= 7
762 && (sep->se_socktype == SOCK_STREAM
763 || sep->se_socktype == SOCK_DGRAM)
764 ) {
765 unsigned i;
766 for (i = 0; i < ARRAY_SIZE(builtins); i++)
767 if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
768 goto found_bi;
769 bb_error_msg("unknown internal service %s", sep->se_service);
770 goto parse_err;
771 found_bi:
772 sep->se_builtin = &builtins[i];
773 /* stream builtins must be "nowait", dgram must be "wait" */
774 if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
775 goto parse_err;
776 }
777 #endif
778 argc = 0;
779 while ((arg = token[6+argc]) != NULL && argc < MAXARGV)
780 sep->se_argv[argc++] = xstrdup(arg);
781 /* Some inetd.conf files have no argv's, not even argv[0].
782 * Fix them up.
783 * (Technically, programs can be execed with argv[0] = NULL,
784 * but many programs do not like that at all) */
785 if (argc == 0)
786 sep->se_argv[0] = xstrdup(sep->se_program);
787
788 /* catch mixups. "<service> stream udp ..." == wtf */
789 if (sep->se_socktype == SOCK_STREAM) {
790 if (sep->se_proto_no == IPPROTO_UDP)
791 goto parse_err;
792 }
793 if (sep->se_socktype == SOCK_DGRAM) {
794 if (sep->se_proto_no == IPPROTO_TCP)
795 goto parse_err;
796 }
797
798 // bb_info_msg(
799 // "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
800 // sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
801 // sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
802
803 /* check if the hostname specifier is a comma separated list
804 * of hostnames. we'll make new entries for each address. */
805 while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
806 nsep = dup_servtab(sep);
807 /* NUL terminate the hostname field of the existing entry,
808 * and make a dup for the new entry. */
809 *hostdelim++ = '\0';
810 nsep->se_local_hostname = xstrdup(hostdelim);
811 nsep->se_next = sep->se_next;
812 sep->se_next = nsep;
813 }
814
815 /* was doing it here: */
816 /* DNS resolution, create copies for each IP address */
817 /* IPv6-ization destroyed it :( */
818
819 return sep;
820 }
821
822 static servtab_t *insert_in_servlist(servtab_t *cp)
823 {
824 servtab_t *sep;
825 sigset_t omask;
826
827 sep = new_servtab();
828 *sep = *cp; /* struct copy */
829 sep->se_fd = -1;
830 #if ENABLE_FEATURE_INETD_RPC
831 sep->se_rpcprog = -1;
832 #endif
833 block_CHLD_HUP_ALRM(&omask);
834 sep->se_next = serv_list;
835 serv_list = sep;
836 restore_sigmask(&omask);
837 return sep;
838 }
839
840 static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
841 {
842 if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
843 return 0;
844 if (strcmp(old->se_service, new->se_service) != 0)
845 return 0;
846 if (strcmp(old->se_proto, new->se_proto) != 0)
847 return 0;
848 return 1;
849 }
850
851 static void reread_config_file(int sig UNUSED_PARAM)
852 {
853 servtab_t *sep, *cp, **sepp;
854 len_and_sockaddr *lsa;
855 sigset_t omask;
856 unsigned n;
857 uint16_t port;
858 int save_errno = errno;
859
860 if (!reopen_config_file())
861 goto ret;
862 for (sep = serv_list; sep; sep = sep->se_next)
863 sep->se_checked = 0;
864
865 goto first_line;
866 while (1) {
867 if (cp == NULL) {
868 first_line:
869 cp = parse_one_line();
870 if (cp == NULL)
871 break;
872 }
873 for (sep = serv_list; sep; sep = sep->se_next)
874 if (same_serv_addr_proto(sep, cp))
875 goto equal_servtab;
876 /* not an "equal" servtab */
877 sep = insert_in_servlist(cp);
878 goto after_check;
879 equal_servtab:
880 {
881 int i;
882
883 block_CHLD_HUP_ALRM(&omask);
884 #if ENABLE_FEATURE_INETD_RPC
885 if (is_rpc_service(sep))
886 unregister_rpc(sep);
887 sep->se_rpcver_lo = cp->se_rpcver_lo;
888 sep->se_rpcver_hi = cp->se_rpcver_hi;
889 #endif
890 if (cp->se_wait == 0) {
891 /* New config says "nowait". If old one
892 * was "wait", we currently may be waiting
893 * for a child (and not accepting connects).
894 * Stop waiting, start listening again.
895 * (if it's not true, this op is harmless) */
896 add_fd_to_set(sep->se_fd);
897 }
898 sep->se_wait = cp->se_wait;
899 sep->se_max = cp->se_max;
900 /* string fields need more love - we don't want to leak them */
901 #define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
902 SWAP(char*, sep->se_user, cp->se_user);
903 SWAP(char*, sep->se_group, cp->se_group);
904 SWAP(char*, sep->se_program, cp->se_program);
905 for (i = 0; i < MAXARGV; i++)
906 SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
907 #undef SWAP
908 restore_sigmask(&omask);
909 free_servtab_strings(cp);
910 }
911 after_check:
912 /* cp->string_fields are consumed by insert_in_servlist()
913 * or freed at this point, cp itself is not yet freed. */
914 sep->se_checked = 1;
915
916 /* create new len_and_sockaddr */
917 switch (sep->se_family) {
918 struct sockaddr_un *sun;
919 case AF_UNIX:
920 lsa = xzalloc_lsa(AF_UNIX);
921 sun = (struct sockaddr_un*)&lsa->u.sa;
922 safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
923 break;
924
925 default: /* case AF_INET, case AF_INET6 */
926 n = bb_strtou(sep->se_service, NULL, 10);
927 #if ENABLE_FEATURE_INETD_RPC
928 if (is_rpc_service(sep)) {
929 sep->se_rpcprog = n;
930 if (errno) { /* se_service is not numeric */
931 struct rpcent *rp = getrpcbyname(sep->se_service);
932 if (rp == NULL) {
933 bb_error_msg("%s: unknown rpc service", sep->se_service);
934 goto next_cp;
935 }
936 sep->se_rpcprog = rp->r_number;
937 }
938 if (sep->se_fd == -1)
939 prepare_socket_fd(sep);
940 if (sep->se_fd != -1)
941 register_rpc(sep);
942 goto next_cp;
943 }
944 #endif
945 /* what port to listen on? */
946 port = htons(n);
947 if (errno || n > 0xffff) { /* se_service is not numeric */
948 char protoname[4];
949 struct servent *sp;
950 /* can result only in "tcp" or "udp": */
951 safe_strncpy(protoname, sep->se_proto, 4);
952 sp = getservbyname(sep->se_service, protoname);
953 if (sp == NULL) {
954 bb_error_msg("%s/%s: unknown service",
955 sep->se_service, sep->se_proto);
956 goto next_cp;
957 }
958 port = sp->s_port;
959 }
960 if (LONE_CHAR(sep->se_local_hostname, '*')) {
961 lsa = xzalloc_lsa(sep->se_family);
962 set_nport(lsa, port);
963 } else {
964 lsa = host_and_af2sockaddr(sep->se_local_hostname,
965 ntohs(port), sep->se_family);
966 if (!lsa) {
967 bb_error_msg("%s/%s: unknown host '%s'",
968 sep->se_service, sep->se_proto,
969 sep->se_local_hostname);
970 goto next_cp;
971 }
972 }
973 break;
974 } /* end of "switch (sep->se_family)" */
975
976 /* did lsa change? Then close/open */
977 if (sep->se_lsa == NULL
978 || lsa->len != sep->se_lsa->len
979 || memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
980 ) {
981 remove_fd_from_set(sep->se_fd);
982 maybe_close(sep->se_fd);
983 free(sep->se_lsa);
984 sep->se_lsa = lsa;
985 sep->se_fd = -1;
986 } else {
987 free(lsa);
988 }
989 if (sep->se_fd == -1)
990 prepare_socket_fd(sep);
991 next_cp:
992 sep = cp->se_next;
993 free(cp);
994 cp = sep;
995 } /* end of "while (1) parse lines" */
996 close_config_file();
997
998 /* Purge anything not looked at above - these are stale entries,
999 * new config file doesnt have them. */
1000 block_CHLD_HUP_ALRM(&omask);
1001 sepp = &serv_list;
1002 while ((sep = *sepp)) {
1003 if (sep->se_checked) {
1004 sepp = &sep->se_next;
1005 continue;
1006 }
1007 *sepp = sep->se_next;
1008 remove_fd_from_set(sep->se_fd);
1009 maybe_close(sep->se_fd);
1010 #if ENABLE_FEATURE_INETD_RPC
1011 if (is_rpc_service(sep))
1012 unregister_rpc(sep);
1013 #endif
1014 if (sep->se_family == AF_UNIX)
1015 unlink(sep->se_service);
1016 free_servtab_strings(sep);
1017 free(sep);
1018 }
1019 restore_sigmask(&omask);
1020 ret:
1021 errno = save_errno;
1022 }
1023
1024 static void reap_child(int sig UNUSED_PARAM)
1025 {
1026 pid_t pid;
1027 int status;
1028 servtab_t *sep;
1029 int save_errno = errno;
1030
1031 for (;;) {
1032 pid = wait_any_nohang(&status);
1033 if (pid <= 0)
1034 break;
1035 for (sep = serv_list; sep; sep = sep->se_next) {
1036 if (sep->se_wait != pid)
1037 continue;
1038 /* One of our "wait" services */
1039 if (WIFEXITED(status) && WEXITSTATUS(status))
1040 bb_error_msg("%s: exit status %u",
1041 sep->se_program, WEXITSTATUS(status));
1042 else if (WIFSIGNALED(status))
1043 bb_error_msg("%s: exit signal %u",
1044 sep->se_program, WTERMSIG(status));
1045 sep->se_wait = 1;
1046 add_fd_to_set(sep->se_fd);
1047 break;
1048 }
1049 }
1050 errno = save_errno;
1051 }
1052
1053 static void retry_network_setup(int sig UNUSED_PARAM)
1054 {
1055 int save_errno = errno;
1056 servtab_t *sep;
1057
1058 alarm_armed = 0;
1059 for (sep = serv_list; sep; sep = sep->se_next) {
1060 if (sep->se_fd == -1) {
1061 prepare_socket_fd(sep);
1062 #if ENABLE_FEATURE_INETD_RPC
1063 if (sep->se_fd != -1 && is_rpc_service(sep))
1064 register_rpc(sep);
1065 #endif
1066 }
1067 }
1068 errno = save_errno;
1069 }
1070
1071 static void clean_up_and_exit(int sig UNUSED_PARAM)
1072 {
1073 servtab_t *sep;
1074
1075 /* XXX signal race walking sep list */
1076 for (sep = serv_list; sep; sep = sep->se_next) {
1077 if (sep->se_fd == -1)
1078 continue;
1079
1080 switch (sep->se_family) {
1081 case AF_UNIX:
1082 unlink(sep->se_service);
1083 break;
1084 default: /* case AF_INET, AF_INET6 */
1085 #if ENABLE_FEATURE_INETD_RPC
1086 if (sep->se_wait == 1 && is_rpc_service(sep))
1087 unregister_rpc(sep); /* XXX signal race */
1088 #endif
1089 break;
1090 }
1091 if (ENABLE_FEATURE_CLEAN_UP)
1092 close(sep->se_fd);
1093 }
1094 remove_pidfile(_PATH_INETDPID);
1095 exit(EXIT_SUCCESS);
1096 }
1097
1098 int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1099 int inetd_main(int argc UNUSED_PARAM, char **argv)
1100 {
1101 struct sigaction sa, saved_pipe_handler;
1102 servtab_t *sep, *sep2;
1103 struct passwd *pwd;
1104 struct group *grp = grp; /* for compiler */
1105 int opt;
1106 pid_t pid;
1107 sigset_t omask;
1108
1109 INIT_G();
1110
1111 real_uid = getuid();
1112 if (real_uid != 0) /* run by non-root user */
1113 config_filename = NULL;
1114
1115 opt_complementary = "R+:q+"; /* -q N, -R N */
1116 opt = getopt32(argv, "R:feq:", &max_concurrency, &global_queuelen);
1117 argv += optind;
1118 //argc -= optind;
1119 if (argv[0])
1120 config_filename = argv[0];
1121 if (config_filename == NULL)
1122 bb_error_msg_and_die("non-root must specify config file");
1123 if (!(opt & 2))
1124 bb_daemonize_or_rexec(0, argv - optind);
1125 else
1126 bb_sanitize_stdio();
1127 if (!(opt & 4)) {
1128 /* LOG_NDELAY: connect to syslog daemon NOW.
1129 * Otherwise, we may open syslog socket
1130 * in vforked child, making opened fds and syslog()
1131 * internal state inconsistent.
1132 * This was observed to leak file descriptors. */
1133 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1134 logmode = LOGMODE_SYSLOG;
1135 }
1136
1137 if (real_uid == 0) {
1138 /* run by root, ensure groups vector gets trashed */
1139 gid_t gid = getgid();
1140 setgroups(1, &gid);
1141 }
1142
1143 write_pidfile(_PATH_INETDPID);
1144
1145 /* never fails under Linux (except if you pass it bad arguments) */
1146 getrlimit(RLIMIT_NOFILE, &rlim_ofile);
1147 rlim_ofile_cur = rlim_ofile.rlim_cur;
1148 if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
1149 rlim_ofile_cur = OPEN_MAX;
1150
1151 memset(&sa, 0, sizeof(sa));
1152 /*sigemptyset(&sa.sa_mask); - memset did it */
1153 sigaddset(&sa.sa_mask, SIGALRM);
1154 sigaddset(&sa.sa_mask, SIGCHLD);
1155 sigaddset(&sa.sa_mask, SIGHUP);
1156 sa.sa_handler = retry_network_setup;
1157 sigaction_set(SIGALRM, &sa);
1158 sa.sa_handler = reread_config_file;
1159 sigaction_set(SIGHUP, &sa);
1160 sa.sa_handler = reap_child;
1161 sigaction_set(SIGCHLD, &sa);
1162 sa.sa_handler = clean_up_and_exit;
1163 sigaction_set(SIGTERM, &sa);
1164 sa.sa_handler = clean_up_and_exit;
1165 sigaction_set(SIGINT, &sa);
1166 sa.sa_handler = SIG_IGN;
1167 sigaction(SIGPIPE, &sa, &saved_pipe_handler);
1168
1169 reread_config_file(SIGHUP); /* load config from file */
1170
1171 for (;;) {
1172 int ready_fd_cnt;
1173 int ctrl, accepted_fd, new_udp_fd;
1174 fd_set readable;
1175
1176 if (maxsock < 0)
1177 recalculate_maxsock();
1178
1179 readable = allsock; /* struct copy */
1180 /* if there are no fds to wait on, we will block
1181 * until signal wakes us up (maxsock == 0, but readable
1182 * never contains fds 0 and 1...) */
1183 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
1184 if (ready_fd_cnt < 0) {
1185 if (errno != EINTR) {
1186 bb_perror_msg("select");
1187 sleep(1);
1188 }
1189 continue;
1190 }
1191
1192 for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
1193 if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1194 continue;
1195
1196 ready_fd_cnt--;
1197 ctrl = sep->se_fd;
1198 accepted_fd = -1;
1199 new_udp_fd = -1;
1200 if (!sep->se_wait) {
1201 if (sep->se_socktype == SOCK_STREAM) {
1202 ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
1203 if (ctrl < 0) {
1204 if (errno != EINTR)
1205 bb_perror_msg("accept (for %s)", sep->se_service);
1206 continue;
1207 }
1208 }
1209 /* "nowait" udp */
1210 if (sep->se_socktype == SOCK_DGRAM
1211 && sep->se_family != AF_UNIX
1212 ) {
1213 /* How udp "nowait" works:
1214 * child peeks at (received and buffered by kernel) UDP packet,
1215 * performs connect() on the socket so that it is linked only
1216 * to this peer. But this also affects parent, because descriptors
1217 * are shared after fork() a-la dup(). When parent performs
1218 * select(), it will see this descriptor connected to the peer (!)
1219 * and still readable, will act on it and mess things up
1220 * (can create many copies of same child, etc).
1221 * Parent must create and use new socket instead. */
1222 new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
1223 if (new_udp_fd < 0) { /* error: eat packet, forget about it */
1224 udp_err:
1225 recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
1226 continue;
1227 }
1228 setsockopt_reuseaddr(new_udp_fd);
1229 /* TODO: better do bind after vfork in parent,
1230 * so that we don't have two wildcard bound sockets
1231 * even for a brief moment? */
1232 if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
1233 close(new_udp_fd);
1234 goto udp_err;
1235 }
1236 }
1237 }
1238
1239 block_CHLD_HUP_ALRM(&omask);
1240 pid = 0;
1241 #ifdef INETD_BUILTINS_ENABLED
1242 /* do we need to fork? */
1243 if (sep->se_builtin == NULL
1244 || (sep->se_socktype == SOCK_STREAM
1245 && sep->se_builtin->bi_fork))
1246 #endif
1247 {
1248 if (sep->se_max != 0) {
1249 if (++sep->se_count == 1)
1250 sep->se_time = monotonic_sec();
1251 else if (sep->se_count >= sep->se_max) {
1252 unsigned now = monotonic_sec();
1253 /* did we accumulate se_max connects too quickly? */
1254 if (now - sep->se_time <= CNT_INTERVAL) {
1255 bb_error_msg("%s/%s: too many connections, pausing",
1256 sep->se_service, sep->se_proto);
1257 remove_fd_from_set(sep->se_fd);
1258 close(sep->se_fd);
1259 sep->se_fd = -1;
1260 sep->se_count = 0;
1261 rearm_alarm(); /* will revive it in RETRYTIME sec */
1262 restore_sigmask(&omask);
1263 maybe_close(accepted_fd);
1264 continue; /* -> check next fd in fd set */
1265 }
1266 sep->se_count = 0;
1267 }
1268 }
1269 /* on NOMMU, streamed chargen
1270 * builtin wouldn't work, but it is
1271 * not allowed on NOMMU (ifdefed out) */
1272 #ifdef INETD_BUILTINS_ENABLED
1273 if (BB_MMU && sep->se_builtin)
1274 pid = fork();
1275 else
1276 #endif
1277 pid = vfork();
1278
1279 if (pid < 0) { /* fork error */
1280 bb_perror_msg("vfork"+1);
1281 sleep(1);
1282 restore_sigmask(&omask);
1283 maybe_close(accepted_fd);
1284 continue; /* -> check next fd in fd set */
1285 }
1286 if (pid == 0)
1287 pid--; /* -1: "we did fork and we are child" */
1288 }
1289 /* if pid == 0 here, we never forked */
1290
1291 if (pid > 0) { /* parent */
1292 if (sep->se_wait) {
1293 /* tcp wait: we passed listening socket to child,
1294 * will wait for child to terminate */
1295 sep->se_wait = pid;
1296 remove_fd_from_set(sep->se_fd);
1297 }
1298 if (new_udp_fd >= 0) {
1299 /* udp nowait: child connected the socket,
1300 * we created and will use new, unconnected one */
1301 xmove_fd(new_udp_fd, sep->se_fd);
1302 }
1303 restore_sigmask(&omask);
1304 maybe_close(accepted_fd);
1305 continue; /* -> check next fd in fd set */
1306 }
1307
1308 /* we are either child or didn't vfork at all */
1309 #ifdef INETD_BUILTINS_ENABLED
1310 if (sep->se_builtin) {
1311 if (pid) { /* "pid" is -1: we did vfork */
1312 close(sep->se_fd); /* listening socket */
1313 logmode = LOGMODE_NONE; /* make xwrite etc silent */
1314 }
1315 restore_sigmask(&omask);
1316 if (sep->se_socktype == SOCK_STREAM)
1317 sep->se_builtin->bi_stream_fn(ctrl, sep);
1318 else
1319 sep->se_builtin->bi_dgram_fn(ctrl, sep);
1320 if (pid) /* we did vfork */
1321 _exit(EXIT_FAILURE);
1322 maybe_close(accepted_fd);
1323 continue; /* -> check next fd in fd set */
1324 }
1325 #endif
1326 /* child */
1327 setsid();
1328 /* "nowait" udp */
1329 if (new_udp_fd >= 0) {
1330 len_and_sockaddr *lsa = xzalloc_lsa(sep->se_family);
1331 /* peek at the packet and remember peer addr */
1332 int r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
1333 &lsa->u.sa, &lsa->len);
1334 if (r < 0)
1335 goto do_exit1;
1336 /* make this socket "connected" to peer addr:
1337 * only packets from this peer will be recv'ed,
1338 * and bare write()/send() will work on it */
1339 connect(ctrl, &lsa->u.sa, lsa->len);
1340 free(lsa);
1341 }
1342 /* prepare env and exec program */
1343 pwd = getpwnam(sep->se_user);
1344 if (pwd == NULL) {
1345 bb_error_msg("%s: no such %s", sep->se_user, "user");
1346 goto do_exit1;
1347 }
1348 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1349 bb_error_msg("%s: no such %s", sep->se_group, "group");
1350 goto do_exit1;
1351 }
1352 if (real_uid != 0 && real_uid != pwd->pw_uid) {
1353 /* a user running private inetd */
1354 bb_error_msg("non-root must run services as himself");
1355 goto do_exit1;
1356 }
1357 if (pwd->pw_uid) {
1358 if (sep->se_group)
1359 pwd->pw_gid = grp->gr_gid;
1360 /* initgroups, setgid, setuid: */
1361 change_identity(pwd);
1362 } else if (sep->se_group) {
1363 xsetgid(grp->gr_gid);
1364 setgroups(1, &grp->gr_gid);
1365 }
1366 if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1367 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1368 bb_perror_msg("setrlimit");
1369
1370 /* closelog(); - WRONG. we are after vfork,
1371 * this may confuse syslog() internal state.
1372 * Let's hope libc sets syslog fd to CLOEXEC...
1373 */
1374 xmove_fd(ctrl, STDIN_FILENO);
1375 xdup2(STDIN_FILENO, STDOUT_FILENO);
1376 /* manpages of inetd I managed to find either say
1377 * that stderr is also redirected to the network,
1378 * or do not talk about redirection at all (!) */
1379 if (!sep->se_wait) /* only for usual "tcp nowait" */
1380 xdup2(STDIN_FILENO, STDERR_FILENO);
1381 /* NB: among others, this loop closes listening sockets
1382 * for nowait stream children */
1383 for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
1384 if (sep2->se_fd != ctrl)
1385 maybe_close(sep2->se_fd);
1386 sigaction_set(SIGPIPE, &saved_pipe_handler);
1387 restore_sigmask(&omask);
1388 BB_EXECVP(sep->se_program, sep->se_argv);
1389 bb_perror_msg("can't execute '%s'", sep->se_program);
1390 do_exit1:
1391 /* eat packet in udp case */
1392 if (sep->se_socktype != SOCK_STREAM)
1393 recv(0, line, LINE_SIZE, MSG_DONTWAIT);
1394 _exit(EXIT_FAILURE);
1395 } /* for (sep = servtab...) */
1396 } /* for (;;) */
1397 }
1398
1399 #if !BB_MMU
1400 static const char *const cat_args[] = { "cat", NULL };
1401 #endif
1402
1403 /*
1404 * Internet services provided internally by inetd:
1405 */
1406 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1407 /* Echo service -- echo data back. */
1408 /* ARGSUSED */
1409 static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
1410 {
1411 #if BB_MMU
1412 while (1) {
1413 ssize_t sz = safe_read(s, line, LINE_SIZE);
1414 if (sz <= 0)
1415 break;
1416 xwrite(s, line, sz);
1417 }
1418 #else
1419 /* We are after vfork here! */
1420 /* move network socket to stdin/stdout */
1421 xmove_fd(s, STDIN_FILENO);
1422 xdup2(STDIN_FILENO, STDOUT_FILENO);
1423 /* no error messages please... */
1424 close(STDERR_FILENO);
1425 xopen(bb_dev_null, O_WRONLY);
1426 BB_EXECVP("cat", (char**)cat_args);
1427 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1428 #endif
1429 }
1430 static void FAST_FUNC echo_dg(int s, servtab_t *sep)
1431 {
1432 enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
1433 char *buf = xmalloc(BUFSIZE); /* too big for stack */
1434 int sz;
1435 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1436
1437 lsa->len = sep->se_lsa->len;
1438 /* dgram builtins are non-forking - DONT BLOCK! */
1439 sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
1440 if (sz > 0)
1441 sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
1442 free(buf);
1443 }
1444 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1445
1446
1447 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1448 /* Discard service -- ignore data. */
1449 /* ARGSUSED */
1450 static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
1451 {
1452 #if BB_MMU
1453 while (safe_read(s, line, LINE_SIZE) > 0)
1454 continue;
1455 #else
1456 /* We are after vfork here! */
1457 /* move network socket to stdin */
1458 xmove_fd(s, STDIN_FILENO);
1459 /* discard output */
1460 close(STDOUT_FILENO);
1461 xopen(bb_dev_null, O_WRONLY);
1462 /* no error messages please... */
1463 xdup2(STDOUT_FILENO, STDERR_FILENO);
1464 BB_EXECVP("cat", (char**)cat_args);
1465 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1466 #endif
1467 }
1468 /* ARGSUSED */
1469 static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
1470 {
1471 /* dgram builtins are non-forking - DONT BLOCK! */
1472 recv(s, line, LINE_SIZE, MSG_DONTWAIT);
1473 }
1474 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1475
1476
1477 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1478 #define LINESIZ 72
1479 static void init_ring(void)
1480 {
1481 int i;
1482
1483 end_ring = ring;
1484 for (i = ' '; i < 127; i++)
1485 *end_ring++ = i;
1486 }
1487 /* Character generator. MMU arches only. */
1488 /* ARGSUSED */
1489 static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
1490 {
1491 char *rs;
1492 int len;
1493 char text[LINESIZ + 2];
1494
1495 if (!end_ring) {
1496 init_ring();
1497 rs = ring;
1498 }
1499
1500 text[LINESIZ] = '\r';
1501 text[LINESIZ + 1] = '\n';
1502 rs = ring;
1503 for (;;) {
1504 len = end_ring - rs;
1505 if (len >= LINESIZ)
1506 memmove(text, rs, LINESIZ);
1507 else {
1508 memmove(text, rs, len);
1509 memmove(text + len, ring, LINESIZ - len);
1510 }
1511 if (++rs == end_ring)
1512 rs = ring;
1513 xwrite(s, text, sizeof(text));
1514 }
1515 }
1516 /* ARGSUSED */
1517 static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
1518 {
1519 int len;
1520 char text[LINESIZ + 2];
1521 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1522
1523 /* Eat UDP packet which started it all */
1524 /* dgram builtins are non-forking - DONT BLOCK! */
1525 lsa->len = sep->se_lsa->len;
1526 if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1527 return;
1528
1529 if (!end_ring) {
1530 init_ring();
1531 ring_pos = ring;
1532 }
1533
1534 len = end_ring - ring_pos;
1535 if (len >= LINESIZ)
1536 memmove(text, ring_pos, LINESIZ);
1537 else {
1538 memmove(text, ring_pos, len);
1539 memmove(text + len, ring, LINESIZ - len);
1540 }
1541 if (++ring_pos == end_ring)
1542 ring_pos = ring;
1543 text[LINESIZ] = '\r';
1544 text[LINESIZ + 1] = '\n';
1545 sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
1546 }
1547 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1548
1549
1550 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1551 /*
1552 * Return a machine readable date and time, in the form of the
1553 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
1554 * returns the number of seconds since midnight, Jan 1, 1970,
1555 * we must add 2208988800 seconds to this figure to make up for
1556 * some seventy years Bell Labs was asleep.
1557 */
1558 static uint32_t machtime(void)
1559 {
1560 struct timeval tv;
1561
1562 gettimeofday(&tv, NULL);
1563 return htonl((uint32_t)(tv.tv_sec + 2208988800));
1564 }
1565 /* ARGSUSED */
1566 static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
1567 {
1568 uint32_t result;
1569
1570 result = machtime();
1571 full_write(s, &result, sizeof(result));
1572 }
1573 static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
1574 {
1575 uint32_t result;
1576 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1577
1578 lsa->len = sep->se_lsa->len;
1579 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1580 return;
1581
1582 result = machtime();
1583 sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
1584 }
1585 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1586
1587
1588 #if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1589 /* Return human-readable time of day */
1590 /* ARGSUSED */
1591 static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
1592 {
1593 time_t t;
1594
1595 t = time(NULL);
1596 fdprintf(s, "%.24s\r\n", ctime(&t));
1597 }
1598 static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
1599 {
1600 time_t t;
1601 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1602
1603 lsa->len = sep->se_lsa->len;
1604 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1605 return;
1606
1607 t = time(NULL);
1608 sprintf(line, "%.24s\r\n", ctime(&t));
1609 sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
1610 }
1611 #endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
Tomato firmware and modifications.