source: MondoRescue/branches/3.2/mindi-busybox/networking/inetd.c@ 3232

Last change on this file since 3232 was 3232, checked in by Bruno Cornec, 10 years ago
  • Update mindi-busybox to 1.21.1
File size: 49.2 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
174#if ENABLE_FEATURE_INETD_RPC
175# if defined(__UCLIBC__) && ! defined(__UCLIBC_HAS_RPC__)
176# error "You need to build uClibc with UCLIBC_HAS_RPC for NFS support"
177# endif
178# include <rpc/rpc.h>
179# include <rpc/pmap_clnt.h>
180#endif
181
182#if !BB_MMU
183/* stream version of chargen is forking but not execing,
184 * can't do that (easily) on NOMMU */
185#undef ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
186#define ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN 0
187#endif
188
189#define CNT_INTERVAL 60 /* servers in CNT_INTERVAL sec. */
190#define RETRYTIME 60 /* retry after bind or server fail */
191
192// TODO: explain, or get rid of setrlimit games
193
194#ifndef RLIMIT_NOFILE
195#define RLIMIT_NOFILE RLIMIT_OFILE
196#endif
197
198#ifndef OPEN_MAX
199#define OPEN_MAX 64
200#endif
201
202/* Reserve some descriptors, 3 stdio + at least: 1 log, 1 conf. file */
203#define FD_MARGIN 8
204
205#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD \
206 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO \
207 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN \
208 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME \
209 || ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
210# define INETD_BUILTINS_ENABLED
211#endif
212
213typedef struct servtab_t {
214 /* The most frequently referenced one: */
215 int se_fd; /* open descriptor */
216 /* NB: 'biggest fields last' saves on code size (~250 bytes) */
217 /* [addr:]service socktype proto wait user[:group] prog [args] */
218 char *se_local_hostname; /* addr to listen on */
219 char *se_service; /* "80" or "www" or "mount/2[-3]" */
220 /* socktype is in se_socktype */ /* "stream" "dgram" "raw" "rdm" "seqpacket" */
221 char *se_proto; /* "unix" or "[rpc/]tcp[6]" */
222#if ENABLE_FEATURE_INETD_RPC
223 int se_rpcprog; /* rpc program number */
224 int se_rpcver_lo; /* rpc program lowest version */
225 int se_rpcver_hi; /* rpc program highest version */
226#define is_rpc_service(sep) ((sep)->se_rpcver_lo != 0)
227#else
228#define is_rpc_service(sep) 0
229#endif
230 pid_t se_wait; /* 0:"nowait", 1:"wait", >1:"wait" */
231 /* and waiting for this pid */
232 socktype_t se_socktype; /* SOCK_STREAM/DGRAM/RDM/... */
233 family_t se_family; /* AF_UNIX/INET[6] */
234 /* se_proto_no is used by RPC code only... hmm */
235 smallint se_proto_no; /* IPPROTO_TCP/UDP, n/a for AF_UNIX */
236 smallint se_checked; /* looked at during merge */
237 unsigned se_max; /* allowed instances per minute */
238 unsigned se_count; /* number started since se_time */
239 unsigned se_time; /* when we started counting */
240 char *se_user; /* user name to run as */
241 char *se_group; /* group name to run as, can be NULL */
242#ifdef INETD_BUILTINS_ENABLED
243 const struct builtin *se_builtin; /* if built-in, description */
244#endif
245 struct servtab_t *se_next;
246 len_and_sockaddr *se_lsa;
247 char *se_program; /* server program */
248#define MAXARGV 20
249 char *se_argv[MAXARGV + 1]; /* program arguments */
250} servtab_t;
251
252#ifdef INETD_BUILTINS_ENABLED
253/* Echo received data */
254#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
255static void FAST_FUNC echo_stream(int, servtab_t *);
256static void FAST_FUNC echo_dg(int, servtab_t *);
257#endif
258/* Internet /dev/null */
259#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
260static void FAST_FUNC discard_stream(int, servtab_t *);
261static void FAST_FUNC discard_dg(int, servtab_t *);
262#endif
263/* Return 32 bit time since 1900 */
264#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
265static void FAST_FUNC machtime_stream(int, servtab_t *);
266static void FAST_FUNC machtime_dg(int, servtab_t *);
267#endif
268/* Return human-readable time */
269#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
270static void FAST_FUNC daytime_stream(int, servtab_t *);
271static void FAST_FUNC daytime_dg(int, servtab_t *);
272#endif
273/* Familiar character generator */
274#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
275static void FAST_FUNC chargen_stream(int, servtab_t *);
276static void FAST_FUNC chargen_dg(int, servtab_t *);
277#endif
278
279struct builtin {
280 /* NB: not necessarily NUL terminated */
281 char bi_service7[7]; /* internally provided service name */
282 uint8_t bi_fork; /* 1 if stream fn should run in child */
283 void (*bi_stream_fn)(int, servtab_t *) FAST_FUNC;
284 void (*bi_dgram_fn)(int, servtab_t *) FAST_FUNC;
285};
286
287static const struct builtin builtins[] = {
288#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
289 { "echo", 1, echo_stream, echo_dg },
290#endif
291#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
292 { "discard", 1, discard_stream, discard_dg },
293#endif
294#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
295 { "chargen", 1, chargen_stream, chargen_dg },
296#endif
297#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
298 { "time", 0, machtime_stream, machtime_dg },
299#endif
300#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
301 { "daytime", 0, daytime_stream, daytime_dg },
302#endif
303};
304#endif /* INETD_BUILTINS_ENABLED */
305
306struct globals {
307 rlim_t rlim_ofile_cur;
308 struct rlimit rlim_ofile;
309 servtab_t *serv_list;
310 int global_queuelen;
311 int maxsock; /* max fd# in allsock, -1: unknown */
312 /* whenever maxsock grows, prev_maxsock is set to new maxsock,
313 * but if maxsock is set to -1, prev_maxsock is not changed */
314 int prev_maxsock;
315 unsigned max_concurrency;
316 smallint alarm_armed;
317 uid_t real_uid; /* user ID who ran us */
318 const char *config_filename;
319 parser_t *parser;
320 char *default_local_hostname;
321#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
322 char *end_ring;
323 char *ring_pos;
324 char ring[128];
325#endif
326 fd_set allsock;
327 /* Used in next_line(), and as scratch read buffer */
328 char line[256]; /* _at least_ 256, see LINE_SIZE */
329} FIX_ALIASING;
330#define G (*(struct globals*)&bb_common_bufsiz1)
331enum { LINE_SIZE = COMMON_BUFSIZE - offsetof(struct globals, line) };
332struct BUG_G_too_big {
333 char BUG_G_too_big[sizeof(G) <= COMMON_BUFSIZE ? 1 : -1];
334};
335#define rlim_ofile_cur (G.rlim_ofile_cur )
336#define rlim_ofile (G.rlim_ofile )
337#define serv_list (G.serv_list )
338#define global_queuelen (G.global_queuelen)
339#define maxsock (G.maxsock )
340#define prev_maxsock (G.prev_maxsock )
341#define max_concurrency (G.max_concurrency)
342#define alarm_armed (G.alarm_armed )
343#define real_uid (G.real_uid )
344#define config_filename (G.config_filename)
345#define parser (G.parser )
346#define default_local_hostname (G.default_local_hostname)
347#define first_ps_byte (G.first_ps_byte )
348#define last_ps_byte (G.last_ps_byte )
349#define end_ring (G.end_ring )
350#define ring_pos (G.ring_pos )
351#define ring (G.ring )
352#define allsock (G.allsock )
353#define line (G.line )
354#define INIT_G() do { \
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 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 goto more;
679 }
680 } else
681 sep->se_local_hostname = xstrdup(default_local_hostname);
682
683 /* service socktype proto wait user[:group] prog [args] */
684 sep->se_service = xstrdup(arg);
685
686 /* socktype proto wait user[:group] prog [args] */
687 if (argc < 6) {
688 parse_err:
689 bb_error_msg("parse error on line %u, line is ignored",
690 parser->lineno);
691 free_servtab_strings(sep);
692 /* Just "goto more" can make sep to carry over e.g.
693 * "rpc"-ness (by having se_rpcver_lo != 0).
694 * We will be more paranoid: */
695 free(sep);
696 goto new;
697 }
698
699 {
700 static const int8_t SOCK_xxx[] ALIGN1 = {
701 -1,
702 SOCK_STREAM, SOCK_DGRAM, SOCK_RDM,
703 SOCK_SEQPACKET, SOCK_RAW
704 };
705 sep->se_socktype = SOCK_xxx[1 + index_in_strings(
706 "stream""\0" "dgram""\0" "rdm""\0"
707 "seqpacket""\0" "raw""\0"
708 , token[1])];
709 }
710
711 /* {unix,[rpc/]{tcp,udp}[6]} wait user[:group] prog [args] */
712 sep->se_proto = arg = xstrdup(token[2]);
713 if (strcmp(arg, "unix") == 0) {
714 sep->se_family = AF_UNIX;
715 } else {
716 char *six;
717 sep->se_family = AF_INET;
718 six = last_char_is(arg, '6');
719 if (six) {
720#if ENABLE_FEATURE_IPV6
721 *six = '\0';
722 sep->se_family = AF_INET6;
723#else
724 bb_error_msg("%s: no support for IPv6", sep->se_proto);
725 goto parse_err;
726#endif
727 }
728 if (strncmp(arg, "rpc/", 4) == 0) {
729#if ENABLE_FEATURE_INETD_RPC
730 unsigned n;
731 arg += 4;
732 p = strchr(sep->se_service, '/');
733 if (p == NULL) {
734 bb_error_msg("no rpc version: '%s'", sep->se_service);
735 goto parse_err;
736 }
737 *p++ = '\0';
738 n = bb_strtou(p, &p, 10);
739 if (n > INT_MAX) {
740 bad_ver_spec:
741 bb_error_msg("bad rpc version");
742 goto parse_err;
743 }
744 sep->se_rpcver_lo = sep->se_rpcver_hi = n;
745 if (*p == '-') {
746 p++;
747 n = bb_strtou(p, &p, 10);
748 if (n > INT_MAX || (int)n < sep->se_rpcver_lo)
749 goto bad_ver_spec;
750 sep->se_rpcver_hi = n;
751 }
752 if (*p != '\0')
753 goto bad_ver_spec;
754#else
755 bb_error_msg("no support for rpc services");
756 goto parse_err;
757#endif
758 }
759 /* we don't really need getprotobyname()! */
760 if (strcmp(arg, "tcp") == 0)
761 sep->se_proto_no = IPPROTO_TCP; /* = 6 */
762 if (strcmp(arg, "udp") == 0)
763 sep->se_proto_no = IPPROTO_UDP; /* = 17 */
764 if (six)
765 *six = '6';
766 if (!sep->se_proto_no) /* not tcp/udp?? */
767 goto parse_err;
768 }
769
770 /* [no]wait[.max] user[:group] prog [args] */
771 arg = token[3];
772 sep->se_max = max_concurrency;
773 p = strchr(arg, '.');
774 if (p) {
775 *p++ = '\0';
776 sep->se_max = bb_strtou(p, NULL, 10);
777 if (errno)
778 goto parse_err;
779 }
780 sep->se_wait = (arg[0] != 'n' || arg[1] != 'o');
781 if (!sep->se_wait) /* "no" seen */
782 arg += 2;
783 if (strcmp(arg, "wait") != 0)
784 goto parse_err;
785
786 /* user[:group] prog [args] */
787 sep->se_user = xstrdup(token[4]);
788 arg = strchr(sep->se_user, '.');
789 if (arg == NULL)
790 arg = strchr(sep->se_user, ':');
791 if (arg) {
792 *arg++ = '\0';
793 sep->se_group = xstrdup(arg);
794 }
795
796 /* prog [args] */
797 sep->se_program = xstrdup(token[5]);
798#ifdef INETD_BUILTINS_ENABLED
799 if (strcmp(sep->se_program, "internal") == 0
800 && strlen(sep->se_service) <= 7
801 && (sep->se_socktype == SOCK_STREAM
802 || sep->se_socktype == SOCK_DGRAM)
803 ) {
804 unsigned i;
805 for (i = 0; i < ARRAY_SIZE(builtins); i++)
806 if (strncmp(builtins[i].bi_service7, sep->se_service, 7) == 0)
807 goto found_bi;
808 bb_error_msg("unknown internal service %s", sep->se_service);
809 goto parse_err;
810 found_bi:
811 sep->se_builtin = &builtins[i];
812 /* stream builtins must be "nowait", dgram must be "wait" */
813 if (sep->se_wait != (sep->se_socktype == SOCK_DGRAM))
814 goto parse_err;
815 }
816#endif
817 argc = 0;
818 while ((arg = token[6+argc]) != NULL && argc < MAXARGV)
819 sep->se_argv[argc++] = xstrdup(arg);
820 /* Some inetd.conf files have no argv's, not even argv[0].
821 * Fix them up.
822 * (Technically, programs can be execed with argv[0] = NULL,
823 * but many programs do not like that at all) */
824 if (argc == 0)
825 sep->se_argv[0] = xstrdup(sep->se_program);
826
827 /* catch mixups. "<service> stream udp ..." == wtf */
828 if (sep->se_socktype == SOCK_STREAM) {
829 if (sep->se_proto_no == IPPROTO_UDP)
830 goto parse_err;
831 }
832 if (sep->se_socktype == SOCK_DGRAM) {
833 if (sep->se_proto_no == IPPROTO_TCP)
834 goto parse_err;
835 }
836
837// bb_info_msg(
838// "ENTRY[%s][%s][%s][%d][%d][%d][%d][%d][%s][%s][%s]",
839// sep->se_local_hostname, sep->se_service, sep->se_proto, sep->se_wait, sep->se_proto_no,
840// sep->se_max, sep->se_count, sep->se_time, sep->se_user, sep->se_group, sep->se_program);
841
842 /* check if the hostname specifier is a comma separated list
843 * of hostnames. we'll make new entries for each address. */
844 while ((hostdelim = strrchr(sep->se_local_hostname, ',')) != NULL) {
845 nsep = dup_servtab(sep);
846 /* NUL terminate the hostname field of the existing entry,
847 * and make a dup for the new entry. */
848 *hostdelim++ = '\0';
849 nsep->se_local_hostname = xstrdup(hostdelim);
850 nsep->se_next = sep->se_next;
851 sep->se_next = nsep;
852 }
853
854 /* was doing it here: */
855 /* DNS resolution, create copies for each IP address */
856 /* IPv6-ization destroyed it :( */
857
858 return sep;
859}
860
861static servtab_t *insert_in_servlist(servtab_t *cp)
862{
863 servtab_t *sep;
864 sigset_t omask;
865
866 sep = new_servtab();
867 *sep = *cp; /* struct copy */
868 sep->se_fd = -1;
869#if ENABLE_FEATURE_INETD_RPC
870 sep->se_rpcprog = -1;
871#endif
872 block_CHLD_HUP_ALRM(&omask);
873 sep->se_next = serv_list;
874 serv_list = sep;
875 restore_sigmask(&omask);
876 return sep;
877}
878
879static int same_serv_addr_proto(servtab_t *old, servtab_t *new)
880{
881 if (strcmp(old->se_local_hostname, new->se_local_hostname) != 0)
882 return 0;
883 if (strcmp(old->se_service, new->se_service) != 0)
884 return 0;
885 if (strcmp(old->se_proto, new->se_proto) != 0)
886 return 0;
887 return 1;
888}
889
890static void reread_config_file(int sig UNUSED_PARAM)
891{
892 servtab_t *sep, *cp, **sepp;
893 len_and_sockaddr *lsa;
894 sigset_t omask;
895 unsigned n;
896 uint16_t port;
897 int save_errno = errno;
898
899 if (!reopen_config_file())
900 goto ret;
901 for (sep = serv_list; sep; sep = sep->se_next)
902 sep->se_checked = 0;
903
904 goto first_line;
905 while (1) {
906 if (cp == NULL) {
907 first_line:
908 cp = parse_one_line();
909 if (cp == NULL)
910 break;
911 }
912 for (sep = serv_list; sep; sep = sep->se_next)
913 if (same_serv_addr_proto(sep, cp))
914 goto equal_servtab;
915 /* not an "equal" servtab */
916 sep = insert_in_servlist(cp);
917 goto after_check;
918 equal_servtab:
919 {
920 int i;
921
922 block_CHLD_HUP_ALRM(&omask);
923#if ENABLE_FEATURE_INETD_RPC
924 if (is_rpc_service(sep))
925 unregister_rpc(sep);
926 sep->se_rpcver_lo = cp->se_rpcver_lo;
927 sep->se_rpcver_hi = cp->se_rpcver_hi;
928#endif
929 if (cp->se_wait == 0) {
930 /* New config says "nowait". If old one
931 * was "wait", we currently may be waiting
932 * for a child (and not accepting connects).
933 * Stop waiting, start listening again.
934 * (if it's not true, this op is harmless) */
935 add_fd_to_set(sep->se_fd);
936 }
937 sep->se_wait = cp->se_wait;
938 sep->se_max = cp->se_max;
939 /* string fields need more love - we don't want to leak them */
940#define SWAP(type, a, b) do { type c = (type)a; a = (type)b; b = (type)c; } while (0)
941 SWAP(char*, sep->se_user, cp->se_user);
942 SWAP(char*, sep->se_group, cp->se_group);
943 SWAP(char*, sep->se_program, cp->se_program);
944 for (i = 0; i < MAXARGV; i++)
945 SWAP(char*, sep->se_argv[i], cp->se_argv[i]);
946#undef SWAP
947 restore_sigmask(&omask);
948 free_servtab_strings(cp);
949 }
950 after_check:
951 /* cp->string_fields are consumed by insert_in_servlist()
952 * or freed at this point, cp itself is not yet freed. */
953 sep->se_checked = 1;
954
955 /* create new len_and_sockaddr */
956 switch (sep->se_family) {
957 struct sockaddr_un *sun;
958 case AF_UNIX:
959 lsa = xzalloc_lsa(AF_UNIX);
960 sun = (struct sockaddr_un*)&lsa->u.sa;
961 safe_strncpy(sun->sun_path, sep->se_service, sizeof(sun->sun_path));
962 break;
963
964 default: /* case AF_INET, case AF_INET6 */
965 n = bb_strtou(sep->se_service, NULL, 10);
966#if ENABLE_FEATURE_INETD_RPC
967 if (is_rpc_service(sep)) {
968 sep->se_rpcprog = n;
969 if (errno) { /* se_service is not numeric */
970 struct rpcent *rp = getrpcbyname(sep->se_service);
971 if (rp == NULL) {
972 bb_error_msg("%s: unknown rpc service", sep->se_service);
973 goto next_cp;
974 }
975 sep->se_rpcprog = rp->r_number;
976 }
977 if (sep->se_fd == -1)
978 prepare_socket_fd(sep);
979 if (sep->se_fd != -1)
980 register_rpc(sep);
981 goto next_cp;
982 }
983#endif
984 /* what port to listen on? */
985 port = htons(n);
986 if (errno || n > 0xffff) { /* se_service is not numeric */
987 char protoname[4];
988 struct servent *sp;
989 /* can result only in "tcp" or "udp": */
990 safe_strncpy(protoname, sep->se_proto, 4);
991 sp = getservbyname(sep->se_service, protoname);
992 if (sp == NULL) {
993 bb_error_msg("%s/%s: unknown service",
994 sep->se_service, sep->se_proto);
995 goto next_cp;
996 }
997 port = sp->s_port;
998 }
999 if (LONE_CHAR(sep->se_local_hostname, '*')) {
1000 lsa = xzalloc_lsa(sep->se_family);
1001 set_nport(&lsa->u.sa, port);
1002 } else {
1003 lsa = host_and_af2sockaddr(sep->se_local_hostname,
1004 ntohs(port), sep->se_family);
1005 if (!lsa) {
1006 bb_error_msg("%s/%s: unknown host '%s'",
1007 sep->se_service, sep->se_proto,
1008 sep->se_local_hostname);
1009 goto next_cp;
1010 }
1011 }
1012 break;
1013 } /* end of "switch (sep->se_family)" */
1014
1015 /* did lsa change? Then close/open */
1016 if (sep->se_lsa == NULL
1017 || lsa->len != sep->se_lsa->len
1018 || memcmp(&lsa->u.sa, &sep->se_lsa->u.sa, lsa->len) != 0
1019 ) {
1020 remove_fd_from_set(sep->se_fd);
1021 maybe_close(sep->se_fd);
1022 free(sep->se_lsa);
1023 sep->se_lsa = lsa;
1024 sep->se_fd = -1;
1025 } else {
1026 free(lsa);
1027 }
1028 if (sep->se_fd == -1)
1029 prepare_socket_fd(sep);
1030 next_cp:
1031 sep = cp->se_next;
1032 free(cp);
1033 cp = sep;
1034 } /* end of "while (1) parse lines" */
1035 close_config_file();
1036
1037 /* Purge anything not looked at above - these are stale entries,
1038 * new config file doesnt have them. */
1039 block_CHLD_HUP_ALRM(&omask);
1040 sepp = &serv_list;
1041 while ((sep = *sepp) != NULL) {
1042 if (sep->se_checked) {
1043 sepp = &sep->se_next;
1044 continue;
1045 }
1046 *sepp = sep->se_next;
1047 remove_fd_from_set(sep->se_fd);
1048 maybe_close(sep->se_fd);
1049#if ENABLE_FEATURE_INETD_RPC
1050 if (is_rpc_service(sep))
1051 unregister_rpc(sep);
1052#endif
1053 if (sep->se_family == AF_UNIX)
1054 unlink(sep->se_service);
1055 free_servtab_strings(sep);
1056 free(sep);
1057 }
1058 restore_sigmask(&omask);
1059 ret:
1060 errno = save_errno;
1061}
1062
1063static void reap_child(int sig UNUSED_PARAM)
1064{
1065 pid_t pid;
1066 int status;
1067 servtab_t *sep;
1068 int save_errno = errno;
1069
1070 for (;;) {
1071 pid = wait_any_nohang(&status);
1072 if (pid <= 0)
1073 break;
1074 for (sep = serv_list; sep; sep = sep->se_next) {
1075 if (sep->se_wait != pid)
1076 continue;
1077 /* One of our "wait" services */
1078 if (WIFEXITED(status) && WEXITSTATUS(status))
1079 bb_error_msg("%s: exit status %u",
1080 sep->se_program, WEXITSTATUS(status));
1081 else if (WIFSIGNALED(status))
1082 bb_error_msg("%s: exit signal %u",
1083 sep->se_program, WTERMSIG(status));
1084 sep->se_wait = 1;
1085 add_fd_to_set(sep->se_fd);
1086 break;
1087 }
1088 }
1089 errno = save_errno;
1090}
1091
1092static void retry_network_setup(int sig UNUSED_PARAM)
1093{
1094 int save_errno = errno;
1095 servtab_t *sep;
1096
1097 alarm_armed = 0;
1098 for (sep = serv_list; sep; sep = sep->se_next) {
1099 if (sep->se_fd == -1) {
1100 prepare_socket_fd(sep);
1101#if ENABLE_FEATURE_INETD_RPC
1102 if (sep->se_fd != -1 && is_rpc_service(sep))
1103 register_rpc(sep);
1104#endif
1105 }
1106 }
1107 errno = save_errno;
1108}
1109
1110static void clean_up_and_exit(int sig UNUSED_PARAM)
1111{
1112 servtab_t *sep;
1113
1114 /* XXX signal race walking sep list */
1115 for (sep = serv_list; sep; sep = sep->se_next) {
1116 if (sep->se_fd == -1)
1117 continue;
1118
1119 switch (sep->se_family) {
1120 case AF_UNIX:
1121 unlink(sep->se_service);
1122 break;
1123 default: /* case AF_INET, AF_INET6 */
1124#if ENABLE_FEATURE_INETD_RPC
1125 if (sep->se_wait == 1 && is_rpc_service(sep))
1126 unregister_rpc(sep); /* XXX signal race */
1127#endif
1128 break;
1129 }
1130 if (ENABLE_FEATURE_CLEAN_UP)
1131 close(sep->se_fd);
1132 }
1133 remove_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
1134 exit(EXIT_SUCCESS);
1135}
1136
1137int inetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
1138int inetd_main(int argc UNUSED_PARAM, char **argv)
1139{
1140 struct sigaction sa, saved_pipe_handler;
1141 servtab_t *sep, *sep2;
1142 struct passwd *pwd;
1143 struct group *grp = grp; /* for compiler */
1144 int opt;
1145 pid_t pid;
1146 sigset_t omask;
1147
1148 INIT_G();
1149
1150 real_uid = getuid();
1151 if (real_uid != 0) /* run by non-root user */
1152 config_filename = NULL;
1153
1154 opt_complementary = "R+:q+"; /* -q N, -R N */
1155 opt = getopt32(argv, "R:feq:", &max_concurrency, &global_queuelen);
1156 argv += optind;
1157 //argc -= optind;
1158 if (argv[0])
1159 config_filename = argv[0];
1160 if (config_filename == NULL)
1161 bb_error_msg_and_die("non-root must specify config file");
1162 if (!(opt & 2))
1163 bb_daemonize_or_rexec(0, argv - optind);
1164 else
1165 bb_sanitize_stdio();
1166 if (!(opt & 4)) {
1167 /* LOG_NDELAY: connect to syslog daemon NOW.
1168 * Otherwise, we may open syslog socket
1169 * in vforked child, making opened fds and syslog()
1170 * internal state inconsistent.
1171 * This was observed to leak file descriptors. */
1172 openlog(applet_name, LOG_PID | LOG_NDELAY, LOG_DAEMON);
1173 logmode = LOGMODE_SYSLOG;
1174 }
1175
1176 if (real_uid == 0) {
1177 /* run by root, ensure groups vector gets trashed */
1178 gid_t gid = getgid();
1179 setgroups(1, &gid);
1180 }
1181
1182 write_pidfile(CONFIG_PID_FILE_PATH "/inetd.pid");
1183
1184 /* never fails under Linux (except if you pass it bad arguments) */
1185 getrlimit(RLIMIT_NOFILE, &rlim_ofile);
1186 rlim_ofile_cur = rlim_ofile.rlim_cur;
1187 if (rlim_ofile_cur == RLIM_INFINITY) /* ! */
1188 rlim_ofile_cur = OPEN_MAX;
1189
1190 memset(&sa, 0, sizeof(sa));
1191 /*sigemptyset(&sa.sa_mask); - memset did it */
1192 sigaddset(&sa.sa_mask, SIGALRM);
1193 sigaddset(&sa.sa_mask, SIGCHLD);
1194 sigaddset(&sa.sa_mask, SIGHUP);
1195//FIXME: explain why no SA_RESTART
1196//FIXME: retry_network_setup is unsafe to run in signal handler (many reasons)!
1197 sa.sa_handler = retry_network_setup;
1198 sigaction_set(SIGALRM, &sa);
1199//FIXME: reread_config_file is unsafe to run in signal handler(many reasons)!
1200 sa.sa_handler = reread_config_file;
1201 sigaction_set(SIGHUP, &sa);
1202//FIXME: reap_child is unsafe to run in signal handler (uses stdio)!
1203 sa.sa_handler = reap_child;
1204 sigaction_set(SIGCHLD, &sa);
1205//FIXME: clean_up_and_exit is unsafe to run in signal handler (uses stdio)!
1206 sa.sa_handler = clean_up_and_exit;
1207 sigaction_set(SIGTERM, &sa);
1208 sa.sa_handler = clean_up_and_exit;
1209 sigaction_set(SIGINT, &sa);
1210 sa.sa_handler = SIG_IGN;
1211 sigaction(SIGPIPE, &sa, &saved_pipe_handler);
1212
1213 reread_config_file(SIGHUP); /* load config from file */
1214
1215 for (;;) {
1216 int ready_fd_cnt;
1217 int ctrl, accepted_fd, new_udp_fd;
1218 fd_set readable;
1219
1220 if (maxsock < 0)
1221 recalculate_maxsock();
1222
1223 readable = allsock; /* struct copy */
1224 /* if there are no fds to wait on, we will block
1225 * until signal wakes us up (maxsock == 0, but readable
1226 * never contains fds 0 and 1...) */
1227 ready_fd_cnt = select(maxsock + 1, &readable, NULL, NULL, NULL);
1228 if (ready_fd_cnt < 0) {
1229 if (errno != EINTR) {
1230 bb_perror_msg("select");
1231 sleep(1);
1232 }
1233 continue;
1234 }
1235 dbg("ready_fd_cnt:%d\n", ready_fd_cnt);
1236
1237 for (sep = serv_list; ready_fd_cnt && sep; sep = sep->se_next) {
1238 if (sep->se_fd == -1 || !FD_ISSET(sep->se_fd, &readable))
1239 continue;
1240
1241 dbg("ready fd:%d\n", sep->se_fd);
1242 ready_fd_cnt--;
1243 ctrl = sep->se_fd;
1244 accepted_fd = -1;
1245 new_udp_fd = -1;
1246 if (!sep->se_wait) {
1247 if (sep->se_socktype == SOCK_STREAM) {
1248 ctrl = accepted_fd = accept(sep->se_fd, NULL, NULL);
1249 dbg("accepted_fd:%d\n", accepted_fd);
1250 if (ctrl < 0) {
1251 if (errno != EINTR)
1252 bb_perror_msg("accept (for %s)", sep->se_service);
1253 continue;
1254 }
1255 }
1256 /* "nowait" udp */
1257 if (sep->se_socktype == SOCK_DGRAM
1258 && sep->se_family != AF_UNIX
1259 ) {
1260/* How udp "nowait" works:
1261 * child peeks at (received and buffered by kernel) UDP packet,
1262 * performs connect() on the socket so that it is linked only
1263 * to this peer. But this also affects parent, because descriptors
1264 * are shared after fork() a-la dup(). When parent performs
1265 * select(), it will see this descriptor connected to the peer (!)
1266 * and still readable, will act on it and mess things up
1267 * (can create many copies of same child, etc).
1268 * Parent must create and use new socket instead. */
1269 new_udp_fd = socket(sep->se_family, SOCK_DGRAM, 0);
1270 dbg("new_udp_fd:%d\n", new_udp_fd);
1271 if (new_udp_fd < 0) { /* error: eat packet, forget about it */
1272 udp_err:
1273 recv(sep->se_fd, line, LINE_SIZE, MSG_DONTWAIT);
1274 continue;
1275 }
1276 setsockopt_reuseaddr(new_udp_fd);
1277 /* TODO: better do bind after fork in parent,
1278 * so that we don't have two wildcard bound sockets
1279 * even for a brief moment? */
1280 if (bind(new_udp_fd, &sep->se_lsa->u.sa, sep->se_lsa->len) < 0) {
1281 dbg("bind(new_udp_fd) failed\n");
1282 close(new_udp_fd);
1283 goto udp_err;
1284 }
1285 dbg("bind(new_udp_fd) succeeded\n");
1286 }
1287 }
1288
1289 block_CHLD_HUP_ALRM(&omask);
1290 pid = 0;
1291#ifdef INETD_BUILTINS_ENABLED
1292 /* do we need to fork? */
1293 if (sep->se_builtin == NULL
1294 || (sep->se_socktype == SOCK_STREAM
1295 && sep->se_builtin->bi_fork))
1296#endif
1297 {
1298 if (sep->se_max != 0) {
1299 if (++sep->se_count == 1)
1300 sep->se_time = monotonic_sec();
1301 else if (sep->se_count >= sep->se_max) {
1302 unsigned now = monotonic_sec();
1303 /* did we accumulate se_max connects too quickly? */
1304 if (now - sep->se_time <= CNT_INTERVAL) {
1305 bb_error_msg("%s/%s: too many connections, pausing",
1306 sep->se_service, sep->se_proto);
1307 remove_fd_from_set(sep->se_fd);
1308 close(sep->se_fd);
1309 sep->se_fd = -1;
1310 sep->se_count = 0;
1311 rearm_alarm(); /* will revive it in RETRYTIME sec */
1312 restore_sigmask(&omask);
1313 maybe_close(new_udp_fd);
1314 maybe_close(accepted_fd);
1315 continue; /* -> check next fd in fd set */
1316 }
1317 sep->se_count = 0;
1318 }
1319 }
1320 /* on NOMMU, streamed chargen
1321 * builtin wouldn't work, but it is
1322 * not allowed on NOMMU (ifdefed out) */
1323#ifdef INETD_BUILTINS_ENABLED
1324 if (BB_MMU && sep->se_builtin)
1325 pid = fork();
1326 else
1327#endif
1328 pid = vfork();
1329
1330 if (pid < 0) { /* fork error */
1331 bb_perror_msg("vfork"+1);
1332 sleep(1);
1333 restore_sigmask(&omask);
1334 maybe_close(new_udp_fd);
1335 maybe_close(accepted_fd);
1336 continue; /* -> check next fd in fd set */
1337 }
1338 if (pid == 0)
1339 pid--; /* -1: "we did fork and we are child" */
1340 }
1341 /* if pid == 0 here, we didn't fork */
1342
1343 if (pid > 0) { /* parent */
1344 if (sep->se_wait) {
1345 /* wait: we passed socket to child,
1346 * will wait for child to terminate */
1347 sep->se_wait = pid;
1348 remove_fd_from_set(sep->se_fd);
1349 }
1350 if (new_udp_fd >= 0) {
1351 /* udp nowait: child connected the socket,
1352 * we created and will use new, unconnected one */
1353 xmove_fd(new_udp_fd, sep->se_fd);
1354 dbg("moved new_udp_fd:%d to sep->se_fd:%d\n", new_udp_fd, sep->se_fd);
1355 }
1356 restore_sigmask(&omask);
1357 maybe_close(accepted_fd);
1358 continue; /* -> check next fd in fd set */
1359 }
1360
1361 /* we are either child or didn't fork at all */
1362#ifdef INETD_BUILTINS_ENABLED
1363 if (sep->se_builtin) {
1364 if (pid) { /* "pid" is -1: we did fork */
1365 close(sep->se_fd); /* listening socket */
1366 dbg("closed sep->se_fd:%d\n", sep->se_fd);
1367 logmode = LOGMODE_NONE; /* make xwrite etc silent */
1368 }
1369 restore_sigmask(&omask);
1370 if (sep->se_socktype == SOCK_STREAM)
1371 sep->se_builtin->bi_stream_fn(ctrl, sep);
1372 else
1373 sep->se_builtin->bi_dgram_fn(ctrl, sep);
1374 if (pid) /* we did fork */
1375 _exit(EXIT_FAILURE);
1376 maybe_close(accepted_fd);
1377 continue; /* -> check next fd in fd set */
1378 }
1379#endif
1380 /* child */
1381 setsid();
1382 /* "nowait" udp */
1383 if (new_udp_fd >= 0) {
1384 len_and_sockaddr *lsa;
1385 int r;
1386
1387 close(new_udp_fd);
1388 dbg("closed new_udp_fd:%d\n", new_udp_fd);
1389 lsa = xzalloc_lsa(sep->se_family);
1390 /* peek at the packet and remember peer addr */
1391 r = recvfrom(ctrl, NULL, 0, MSG_PEEK|MSG_DONTWAIT,
1392 &lsa->u.sa, &lsa->len);
1393 if (r < 0)
1394 goto do_exit1;
1395 /* make this socket "connected" to peer addr:
1396 * only packets from this peer will be recv'ed,
1397 * and bare write()/send() will work on it */
1398 connect(ctrl, &lsa->u.sa, lsa->len);
1399 dbg("connected ctrl:%d to remote peer\n", ctrl);
1400 free(lsa);
1401 }
1402 /* prepare env and exec program */
1403 pwd = getpwnam(sep->se_user);
1404 if (pwd == NULL) {
1405 bb_error_msg("%s: no such %s", sep->se_user, "user");
1406 goto do_exit1;
1407 }
1408 if (sep->se_group && (grp = getgrnam(sep->se_group)) == NULL) {
1409 bb_error_msg("%s: no such %s", sep->se_group, "group");
1410 goto do_exit1;
1411 }
1412 if (real_uid != 0 && real_uid != pwd->pw_uid) {
1413 /* a user running private inetd */
1414 bb_error_msg("non-root must run services as himself");
1415 goto do_exit1;
1416 }
1417 if (pwd->pw_uid != 0) {
1418 if (sep->se_group)
1419 pwd->pw_gid = grp->gr_gid;
1420 /* initgroups, setgid, setuid: */
1421 change_identity(pwd);
1422 } else if (sep->se_group) {
1423 xsetgid(grp->gr_gid);
1424 setgroups(1, &grp->gr_gid);
1425 }
1426 if (rlim_ofile.rlim_cur != rlim_ofile_cur)
1427 if (setrlimit(RLIMIT_NOFILE, &rlim_ofile) < 0)
1428 bb_perror_msg("setrlimit");
1429
1430 /* closelog(); - WRONG. we are after vfork,
1431 * this may confuse syslog() internal state.
1432 * Let's hope libc sets syslog fd to CLOEXEC...
1433 */
1434 xmove_fd(ctrl, STDIN_FILENO);
1435 xdup2(STDIN_FILENO, STDOUT_FILENO);
1436 dbg("moved ctrl:%d to fd 0,1[,2]\n", ctrl);
1437 /* manpages of inetd I managed to find either say
1438 * that stderr is also redirected to the network,
1439 * or do not talk about redirection at all (!) */
1440 if (!sep->se_wait) /* only for usual "tcp nowait" */
1441 xdup2(STDIN_FILENO, STDERR_FILENO);
1442 /* NB: among others, this loop closes listening sockets
1443 * for nowait stream children */
1444 for (sep2 = serv_list; sep2; sep2 = sep2->se_next)
1445 if (sep2->se_fd != ctrl)
1446 maybe_close(sep2->se_fd);
1447 sigaction_set(SIGPIPE, &saved_pipe_handler);
1448 restore_sigmask(&omask);
1449 dbg("execing:'%s'\n", sep->se_program);
1450 BB_EXECVP(sep->se_program, sep->se_argv);
1451 bb_perror_msg("can't execute '%s'", sep->se_program);
1452 do_exit1:
1453 /* eat packet in udp case */
1454 if (sep->se_socktype != SOCK_STREAM)
1455 recv(0, line, LINE_SIZE, MSG_DONTWAIT);
1456 _exit(EXIT_FAILURE);
1457 } /* for (sep = servtab...) */
1458 } /* for (;;) */
1459}
1460
1461#if !BB_MMU
1462static const char *const cat_args[] = { "cat", NULL };
1463#endif
1464
1465/*
1466 * Internet services provided internally by inetd:
1467 */
1468#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_ECHO
1469/* Echo service -- echo data back. */
1470/* ARGSUSED */
1471static void FAST_FUNC echo_stream(int s, servtab_t *sep UNUSED_PARAM)
1472{
1473#if BB_MMU
1474 while (1) {
1475 ssize_t sz = safe_read(s, line, LINE_SIZE);
1476 if (sz <= 0)
1477 break;
1478 xwrite(s, line, sz);
1479 }
1480#else
1481 /* We are after vfork here! */
1482 /* move network socket to stdin/stdout */
1483 xmove_fd(s, STDIN_FILENO);
1484 xdup2(STDIN_FILENO, STDOUT_FILENO);
1485 /* no error messages please... */
1486 close(STDERR_FILENO);
1487 xopen(bb_dev_null, O_WRONLY);
1488 BB_EXECVP("cat", (char**)cat_args);
1489 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1490#endif
1491}
1492static void FAST_FUNC echo_dg(int s, servtab_t *sep)
1493{
1494 enum { BUFSIZE = 12*1024 }; /* for jumbo sized packets! :) */
1495 char *buf = xmalloc(BUFSIZE); /* too big for stack */
1496 int sz;
1497 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1498
1499 lsa->len = sep->se_lsa->len;
1500 /* dgram builtins are non-forking - DONT BLOCK! */
1501 sz = recvfrom(s, buf, BUFSIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len);
1502 if (sz > 0)
1503 sendto(s, buf, sz, 0, &lsa->u.sa, lsa->len);
1504 free(buf);
1505}
1506#endif /* FEATURE_INETD_SUPPORT_BUILTIN_ECHO */
1507
1508
1509#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DISCARD
1510/* Discard service -- ignore data. */
1511/* ARGSUSED */
1512static void FAST_FUNC discard_stream(int s, servtab_t *sep UNUSED_PARAM)
1513{
1514#if BB_MMU
1515 while (safe_read(s, line, LINE_SIZE) > 0)
1516 continue;
1517#else
1518 /* We are after vfork here! */
1519 /* move network socket to stdin */
1520 xmove_fd(s, STDIN_FILENO);
1521 /* discard output */
1522 close(STDOUT_FILENO);
1523 xopen(bb_dev_null, O_WRONLY);
1524 /* no error messages please... */
1525 xdup2(STDOUT_FILENO, STDERR_FILENO);
1526 BB_EXECVP("cat", (char**)cat_args);
1527 /* on failure we return to main, which does exit(EXIT_FAILURE) */
1528#endif
1529}
1530/* ARGSUSED */
1531static void FAST_FUNC discard_dg(int s, servtab_t *sep UNUSED_PARAM)
1532{
1533 /* dgram builtins are non-forking - DONT BLOCK! */
1534 recv(s, line, LINE_SIZE, MSG_DONTWAIT);
1535}
1536#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DISCARD */
1537
1538
1539#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN
1540#define LINESIZ 72
1541static void init_ring(void)
1542{
1543 int i;
1544
1545 end_ring = ring;
1546 for (i = ' '; i < 127; i++)
1547 *end_ring++ = i;
1548}
1549/* Character generator. MMU arches only. */
1550/* ARGSUSED */
1551static void FAST_FUNC chargen_stream(int s, servtab_t *sep UNUSED_PARAM)
1552{
1553 char *rs;
1554 int len;
1555 char text[LINESIZ + 2];
1556
1557 if (!end_ring) {
1558 init_ring();
1559 rs = ring;
1560 }
1561
1562 text[LINESIZ] = '\r';
1563 text[LINESIZ + 1] = '\n';
1564 rs = ring;
1565 for (;;) {
1566 len = end_ring - rs;
1567 if (len >= LINESIZ)
1568 memmove(text, rs, LINESIZ);
1569 else {
1570 memmove(text, rs, len);
1571 memmove(text + len, ring, LINESIZ - len);
1572 }
1573 if (++rs == end_ring)
1574 rs = ring;
1575 xwrite(s, text, sizeof(text));
1576 }
1577}
1578/* ARGSUSED */
1579static void FAST_FUNC chargen_dg(int s, servtab_t *sep)
1580{
1581 int len;
1582 char text[LINESIZ + 2];
1583 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1584
1585 /* Eat UDP packet which started it all */
1586 /* dgram builtins are non-forking - DONT BLOCK! */
1587 lsa->len = sep->se_lsa->len;
1588 if (recvfrom(s, text, sizeof(text), MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1589 return;
1590
1591 if (!end_ring) {
1592 init_ring();
1593 ring_pos = ring;
1594 }
1595
1596 len = end_ring - ring_pos;
1597 if (len >= LINESIZ)
1598 memmove(text, ring_pos, LINESIZ);
1599 else {
1600 memmove(text, ring_pos, len);
1601 memmove(text + len, ring, LINESIZ - len);
1602 }
1603 if (++ring_pos == end_ring)
1604 ring_pos = ring;
1605 text[LINESIZ] = '\r';
1606 text[LINESIZ + 1] = '\n';
1607 sendto(s, text, sizeof(text), 0, &lsa->u.sa, lsa->len);
1608}
1609#endif /* FEATURE_INETD_SUPPORT_BUILTIN_CHARGEN */
1610
1611
1612#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_TIME
1613/*
1614 * Return a machine readable date and time, in the form of the
1615 * number of seconds since midnight, Jan 1, 1900. Since gettimeofday
1616 * returns the number of seconds since midnight, Jan 1, 1970,
1617 * we must add 2208988800 seconds to this figure to make up for
1618 * some seventy years Bell Labs was asleep.
1619 */
1620static uint32_t machtime(void)
1621{
1622 struct timeval tv;
1623
1624 gettimeofday(&tv, NULL);
1625 return htonl((uint32_t)(tv.tv_sec + 2208988800));
1626}
1627/* ARGSUSED */
1628static void FAST_FUNC machtime_stream(int s, servtab_t *sep UNUSED_PARAM)
1629{
1630 uint32_t result;
1631
1632 result = machtime();
1633 full_write(s, &result, sizeof(result));
1634}
1635static void FAST_FUNC machtime_dg(int s, servtab_t *sep)
1636{
1637 uint32_t result;
1638 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1639
1640 lsa->len = sep->se_lsa->len;
1641 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1642 return;
1643
1644 result = machtime();
1645 sendto(s, &result, sizeof(result), 0, &lsa->u.sa, lsa->len);
1646}
1647#endif /* FEATURE_INETD_SUPPORT_BUILTIN_TIME */
1648
1649
1650#if ENABLE_FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME
1651/* Return human-readable time of day */
1652/* ARGSUSED */
1653static void FAST_FUNC daytime_stream(int s, servtab_t *sep UNUSED_PARAM)
1654{
1655 time_t t;
1656
1657 t = time(NULL);
1658 fdprintf(s, "%.24s\r\n", ctime(&t));
1659}
1660static void FAST_FUNC daytime_dg(int s, servtab_t *sep)
1661{
1662 time_t t;
1663 len_and_sockaddr *lsa = alloca(LSA_LEN_SIZE + sep->se_lsa->len);
1664
1665 lsa->len = sep->se_lsa->len;
1666 if (recvfrom(s, line, LINE_SIZE, MSG_DONTWAIT, &lsa->u.sa, &lsa->len) < 0)
1667 return;
1668
1669 t = time(NULL);
1670 sprintf(line, "%.24s\r\n", ctime(&t));
1671 sendto(s, line, strlen(line), 0, &lsa->u.sa, lsa->len);
1672}
1673#endif /* FEATURE_INETD_SUPPORT_BUILTIN_DAYTIME */
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