xref: /original-bsd/usr.sbin/inetd/inetd.c (revision 4c3b28fe)
1 /*
2  * Copyright (c) 1983 Regents of the University of California.
3  * All rights reserved.
4  *
5  * Redistribution and use in source and binary forms are permitted
6  * provided that the above copyright notice and this paragraph are
7  * duplicated in all such forms and that any documentation,
8  * advertising materials, and other materials related to such
9  * distribution and use acknowledge that the software was developed
10  * by the University of California, Berkeley.  The name of the
11  * University may not be used to endorse or promote products derived
12  * from this software without specific prior written permission.
13  * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
14  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
15  * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
16  */
17 
18 #ifndef lint
19 char copyright[] =
20 "@(#) Copyright (c) 1983 Regents of the University of California.\n\
21  All rights reserved.\n";
22 #endif /* not lint */
23 
24 #ifndef lint
25 static char sccsid[] = "@(#)inetd.c	5.20 (Berkeley) 04/04/90";
26 #endif /* not lint */
27 
28 /*
29  * Inetd - Internet super-server
30  *
31  * This program invokes all internet services as needed.
32  * connection-oriented services are invoked each time a
33  * connection is made, by creating a process.  This process
34  * is passed the connection as file descriptor 0 and is
35  * expected to do a getpeername to find out the source host
36  * and port.
37  *
38  * Datagram oriented services are invoked when a datagram
39  * arrives; a process is created and passed a pending message
40  * on file descriptor 0.  Datagram servers may either connect
41  * to their peer, freeing up the original socket for inetd
42  * to receive further messages on, or ``take over the socket'',
43  * processing all arriving datagrams and, eventually, timing
44  * out.	 The first type of server is said to be ``multi-threaded'';
45  * the second type of server ``single-threaded''.
46  *
47  * Inetd uses a configuration file which is read at startup
48  * and, possibly, at some later time in response to a hangup signal.
49  * The configuration file is ``free format'' with fields given in the
50  * order shown below.  Continuation lines for an entry must being with
51  * a space or tab.  All fields must be present in each entry.
52  *
53  *	service name			must be in /etc/services
54  *	socket type			stream/dgram/raw/rdm/seqpacket
55  *	protocol			must be in /etc/protocols
56  *	wait/nowait			single-threaded/multi-threaded
57  *	user				user to run daemon as
58  *	server program			full path name
59  *	server program arguments	maximum of MAXARGS (20)
60  *
61  * Comment lines are indicated by a `#' in column 1.
62  */
63 #include <sys/param.h>
64 #include <sys/stat.h>
65 #include <sys/ioctl.h>
66 #include <sys/socket.h>
67 #include <sys/file.h>
68 #include <sys/wait.h>
69 #include <sys/time.h>
70 #include <sys/resource.h>
71 
72 #include <netinet/in.h>
73 #include <arpa/inet.h>
74 
75 #include <errno.h>
76 #include <signal.h>
77 #include <netdb.h>
78 #include <syslog.h>
79 #include <pwd.h>
80 #include <stdio.h>
81 #include <strings.h>
82 #include "pathnames.h"
83 
84 #define	TOOMANY		40		/* don't start more than TOOMANY */
85 #define	CNT_INTVL	60		/* servers in CNT_INTVL sec. */
86 #define	RETRYTIME	(60*10)		/* retry after bind or server fail */
87 
88 #define	SIGBLOCK	(sigmask(SIGCHLD)|sigmask(SIGHUP)|sigmask(SIGALRM))
89 
90 extern	int errno;
91 
92 void	config(), reapchild(), retry();
93 char	*index();
94 char	*malloc();
95 
96 int	debug = 0;
97 int	nsock, maxsock;
98 fd_set	allsock;
99 int	options;
100 int	timingout;
101 struct	servent *sp;
102 
103 struct	servtab {
104 	char	*se_service;		/* name of service */
105 	int	se_socktype;		/* type of socket to use */
106 	char	*se_proto;		/* protocol used */
107 	short	se_wait;		/* single threaded server */
108 	short	se_checked;		/* looked at during merge */
109 	char	*se_user;		/* user name to run as */
110 	struct	biltin *se_bi;		/* if built-in, description */
111 	char	*se_server;		/* server program */
112 #define	MAXARGV 20
113 	char	*se_argv[MAXARGV+1];	/* program arguments */
114 	int	se_fd;			/* open descriptor */
115 	struct	sockaddr_in se_ctrladdr;/* bound address */
116 	int	se_count;		/* number started since se_time */
117 	struct	timeval se_time;	/* start of se_count */
118 	struct	servtab *se_next;
119 } *servtab;
120 
121 int echo_stream(), discard_stream(), machtime_stream();
122 int daytime_stream(), chargen_stream();
123 int echo_dg(), discard_dg(), machtime_dg(), daytime_dg(), chargen_dg();
124 
125 struct biltin {
126 	char	*bi_service;		/* internally provided service name */
127 	int	bi_socktype;		/* type of socket supported */
128 	short	bi_fork;		/* 1 if should fork before call */
129 	short	bi_wait;		/* 1 if should wait for child */
130 	int	(*bi_fn)();		/* function which performs it */
131 } biltins[] = {
132 	/* Echo received data */
133 	"echo",		SOCK_STREAM,	1, 0,	echo_stream,
134 	"echo",		SOCK_DGRAM,	0, 0,	echo_dg,
135 
136 	/* Internet /dev/null */
137 	"discard",	SOCK_STREAM,	1, 0,	discard_stream,
138 	"discard",	SOCK_DGRAM,	0, 0,	discard_dg,
139 
140 	/* Return 32 bit time since 1970 */
141 	"time",		SOCK_STREAM,	0, 0,	machtime_stream,
142 	"time",		SOCK_DGRAM,	0, 0,	machtime_dg,
143 
144 	/* Return human-readable time */
145 	"daytime",	SOCK_STREAM,	0, 0,	daytime_stream,
146 	"daytime",	SOCK_DGRAM,	0, 0,	daytime_dg,
147 
148 	/* Familiar character generator */
149 	"chargen",	SOCK_STREAM,	1, 0,	chargen_stream,
150 	"chargen",	SOCK_DGRAM,	0, 0,	chargen_dg,
151 	0
152 };
153 
154 #define NUMINT	(sizeof(intab) / sizeof(struct inent))
155 char	*CONFIG = _PATH_INETDCONF;
156 char	**Argv;
157 char 	*LastArg;
158 
159 main(argc, argv, envp)
160 	int argc;
161 	char *argv[], *envp[];
162 {
163 	extern char *optarg;
164 	extern int optind;
165 	register struct servtab *sep;
166 	register struct passwd *pwd;
167 	register int tmpint;
168 	struct sigvec sv;
169 	int ch, pid, dofork;
170 	char buf[50];
171 
172 	Argv = argv;
173 	if (envp == 0 || *envp == 0)
174 		envp = argv;
175 	while (*envp)
176 		envp++;
177 	LastArg = envp[-1] + strlen(envp[-1]);
178 
179 	while ((ch = getopt(argc, argv, "d")) != EOF)
180 		switch(ch) {
181 		case 'd':
182 			debug = 1;
183 			options |= SO_DEBUG;
184 			break;
185 		case '?':
186 		default:
187 			fprintf(stderr, "usage: inetd [-d]");
188 			exit(1);
189 		}
190 	argc -= optind;
191 	argv += optind;
192 
193 	if (argc > 0)
194 		CONFIG = argv[0];
195 	if (debug == 0) {
196 		if (fork())
197 			exit(0);
198 		for (tmpint = 0; tmpint < 10; tmpint++)
199 			(void) close(tmpint);
200 		(void) open("/", O_RDONLY);
201 		(void) dup2(0, 1);
202 		(void) dup2(0, 2);
203 		tmpint = open(_PATH_TTY, O_RDWR);
204 		if (tmpint > 0) {
205 			ioctl(tmpint, TIOCNOTTY, (char *)0);
206 			close(tmpint);
207 		}
208 		(void) setpgrp(0, 0);
209 		(void) signal(SIGTSTP, SIG_IGN);
210 		(void) signal(SIGTTIN, SIG_IGN);
211 		(void) signal(SIGTTOU, SIG_IGN);
212 	}
213 	openlog("inetd", LOG_PID | LOG_NOWAIT, LOG_DAEMON);
214 	bzero((char *)&sv, sizeof(sv));
215 	sv.sv_mask = SIGBLOCK;
216 	sv.sv_handler = retry;
217 	sigvec(SIGALRM, &sv, (struct sigvec *)0);
218 	config();
219 	sv.sv_handler = config;
220 	sigvec(SIGHUP, &sv, (struct sigvec *)0);
221 	sv.sv_handler = reapchild;
222 	sigvec(SIGCHLD, &sv, (struct sigvec *)0);
223 
224 	{
225 		/* space for daemons to overwrite environment for ps */
226 #define	DUMMYSIZE	100
227 		char dummy[DUMMYSIZE];
228 
229 		(void)memset(dummy, 'x', sizeof(DUMMYSIZE) - 1);
230 		dummy[DUMMYSIZE - 1] = '\0';
231 		(void)setenv("inetd_dummy", dummy, 1);
232 	}
233 
234 	for (;;) {
235 	    int n, ctrl;
236 	    fd_set readable;
237 
238 	    if (nsock == 0) {
239 		(void) sigblock(SIGBLOCK);
240 		while (nsock == 0)
241 		    sigpause(0L);
242 		(void) sigsetmask(0L);
243 	    }
244 	    readable = allsock;
245 	    if ((n = select(maxsock + 1, &readable, (fd_set *)0,
246 		(fd_set *)0, (struct timeval *)0)) <= 0) {
247 		    if (n < 0 && errno != EINTR)
248 			syslog(LOG_WARNING, "select: %m\n");
249 		    sleep(1);
250 		    continue;
251 	    }
252 	    for (sep = servtab; n && sep; sep = sep->se_next)
253 	    if (FD_ISSET(sep->se_fd, &readable)) {
254 		n--;
255 		if (debug)
256 			fprintf(stderr, "someone wants %s\n", sep->se_service);
257 		if (!sep->se_wait && sep->se_socktype == SOCK_STREAM) {
258 			ctrl = accept(sep->se_fd, (struct sockaddr *)0,
259 			    (int *)0);
260 			if (debug)
261 				fprintf(stderr, "accept, ctrl %d\n", ctrl);
262 			if (ctrl < 0) {
263 				if (errno == EINTR)
264 					continue;
265 				syslog(LOG_WARNING, "accept: %m");
266 				continue;
267 			}
268 		} else
269 			ctrl = sep->se_fd;
270 		(void) sigblock(SIGBLOCK);
271 		pid = 0;
272 		dofork = (sep->se_bi == 0 || sep->se_bi->bi_fork);
273 		if (dofork) {
274 			if (sep->se_count++ == 0)
275 			    (void)gettimeofday(&sep->se_time,
276 			        (struct timezone *)0);
277 			else if (sep->se_count >= TOOMANY) {
278 				struct timeval now;
279 
280 				(void)gettimeofday(&now, (struct timezone *)0);
281 				if (now.tv_sec - sep->se_time.tv_sec >
282 				    CNT_INTVL) {
283 					sep->se_time = now;
284 					sep->se_count = 1;
285 				} else {
286 					syslog(LOG_ERR,
287 			"%s/%s server failing (looping), service terminated\n",
288 					    sep->se_service, sep->se_proto);
289 					FD_CLR(sep->se_fd, &allsock);
290 					(void) close(sep->se_fd);
291 					sep->se_fd = -1;
292 					sep->se_count = 0;
293 					nsock--;
294 					sigsetmask(0L);
295 					if (!timingout) {
296 						timingout = 1;
297 						alarm(RETRYTIME);
298 					}
299 					continue;
300 				}
301 			}
302 			pid = fork();
303 		}
304 		if (pid < 0) {
305 			if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
306 				close(ctrl);
307 			sigsetmask(0L);
308 			sleep(1);
309 			continue;
310 		}
311 		if (pid && sep->se_wait) {
312 			sep->se_wait = pid;
313 			FD_CLR(sep->se_fd, &allsock);
314 			nsock--;
315 		}
316 		sigsetmask(0L);
317 		if (pid == 0) {
318 			if (debug) {
319 				if (dofork &&
320 				    (tmpint = open(_PATH_TTY, O_RDWR)) > 0) {
321 					ioctl(tmpint, TIOCNOTTY, 0);
322 					close(tmpint);
323 				}
324 				(void) setpgrp(0, 0);
325 				(void) signal(SIGTSTP, SIG_IGN);
326 				(void) signal(SIGTTIN, SIG_IGN);
327 				(void) signal(SIGTTOU, SIG_IGN);
328 			}
329 			if (dofork)
330 				for (tmpint = getdtablesize(); --tmpint > 2; )
331 					if (tmpint != ctrl)
332 						close(tmpint);
333 			if (sep->se_bi)
334 				(*sep->se_bi->bi_fn)(ctrl, sep);
335 			else {
336 				dup2(ctrl, 0);
337 				close(ctrl);
338 				dup2(0, 1);
339 				dup2(0, 2);
340 				if ((pwd = getpwnam(sep->se_user)) == NULL) {
341 					syslog(LOG_ERR,
342 						"getpwnam: %s: No such user",
343 						sep->se_user);
344 					if (sep->se_socktype != SOCK_STREAM)
345 						recv(0, buf, sizeof (buf), 0);
346 					_exit(1);
347 				}
348 				if (pwd->pw_uid) {
349 					(void) setgid((gid_t)pwd->pw_gid);
350 					initgroups(pwd->pw_name, pwd->pw_gid);
351 					(void) setuid((uid_t)pwd->pw_uid);
352 				}
353 				if (debug)
354 					fprintf(stderr, "%d execl %s\n",
355 					    getpid(), sep->se_server);
356 				execv(sep->se_server, sep->se_argv);
357 				if (sep->se_socktype != SOCK_STREAM)
358 					recv(0, buf, sizeof (buf), 0);
359 				syslog(LOG_ERR, "execv %s: %m", sep->se_server);
360 				_exit(1);
361 			}
362 		}
363 		if (!sep->se_wait && sep->se_socktype == SOCK_STREAM)
364 			close(ctrl);
365 	    }
366 	}
367 }
368 
369 void
370 reapchild()
371 {
372 	union wait status;
373 	int pid;
374 	register struct servtab *sep;
375 
376 	for (;;) {
377 		pid = wait3(&status, WNOHANG, (struct rusage *)0);
378 		if (pid <= 0)
379 			break;
380 		if (debug)
381 			fprintf(stderr, "%d reaped\n", pid);
382 		for (sep = servtab; sep; sep = sep->se_next)
383 			if (sep->se_wait == pid) {
384 				if (status.w_status)
385 					syslog(LOG_WARNING,
386 					    "%s: exit status 0x%x",
387 					    sep->se_server, status);
388 				if (debug)
389 					fprintf(stderr, "restored %s, fd %d\n",
390 					    sep->se_service, sep->se_fd);
391 				FD_SET(sep->se_fd, &allsock);
392 				nsock++;
393 				sep->se_wait = 1;
394 			}
395 	}
396 }
397 
398 void
399 config()
400 {
401 	register struct servtab *sep, *cp, **sepp;
402 	struct servtab *getconfigent(), *enter();
403 	long omask;
404 
405 	if (!setconfig()) {
406 		syslog(LOG_ERR, "%s: %m", CONFIG);
407 		return;
408 	}
409 	for (sep = servtab; sep; sep = sep->se_next)
410 		sep->se_checked = 0;
411 	while (cp = getconfigent()) {
412 		for (sep = servtab; sep; sep = sep->se_next)
413 			if (strcmp(sep->se_service, cp->se_service) == 0 &&
414 			    strcmp(sep->se_proto, cp->se_proto) == 0)
415 				break;
416 		if (sep != 0) {
417 			int i;
418 
419 			omask = sigblock(SIGBLOCK);
420 			/*
421 			 * sep->se_wait may be holding the pid of a daemon
422 			 * that we're waiting for.  If so, don't overwrite
423 			 * it unless the config file explicitly says don't
424 			 * wait.
425 			 */
426 			if (cp->se_bi == 0 &&
427 			    (sep->se_wait == 1 || cp->se_wait == 0))
428 				sep->se_wait = cp->se_wait;
429 #define SWAP(a, b) { char *c = a; a = b; b = c; }
430 			if (cp->se_user)
431 				SWAP(sep->se_user, cp->se_user);
432 			if (cp->se_server)
433 				SWAP(sep->se_server, cp->se_server);
434 			for (i = 0; i < MAXARGV; i++)
435 				SWAP(sep->se_argv[i], cp->se_argv[i]);
436 			sigsetmask(omask);
437 			freeconfig(cp);
438 			if (debug)
439 				print_service("REDO", sep);
440 		} else {
441 			sep = enter(cp);
442 			if (debug)
443 				print_service("ADD ", sep);
444 		}
445 		sep->se_checked = 1;
446 		sp = getservbyname(sep->se_service, sep->se_proto);
447 		if (sp == 0) {
448 			syslog(LOG_ERR, "%s/%s: unknown service",
449 			    sep->se_service, sep->se_proto);
450 			continue;
451 		}
452 		if (sp->s_port != sep->se_ctrladdr.sin_port) {
453 			sep->se_ctrladdr.sin_port = sp->s_port;
454 			if (sep->se_fd != -1)
455 				(void) close(sep->se_fd);
456 			sep->se_fd = -1;
457 		}
458 		if (sep->se_fd == -1)
459 			setup(sep);
460 	}
461 	endconfig();
462 	/*
463 	 * Purge anything not looked at above.
464 	 */
465 	omask = sigblock(SIGBLOCK);
466 	sepp = &servtab;
467 	while (sep = *sepp) {
468 		if (sep->se_checked) {
469 			sepp = &sep->se_next;
470 			continue;
471 		}
472 		*sepp = sep->se_next;
473 		if (sep->se_fd != -1) {
474 			FD_CLR(sep->se_fd, &allsock);
475 			nsock--;
476 			(void) close(sep->se_fd);
477 		}
478 		if (debug)
479 			print_service("FREE", sep);
480 		freeconfig(sep);
481 		free((char *)sep);
482 	}
483 	(void) sigsetmask(omask);
484 }
485 
486 void
487 retry()
488 {
489 	register struct servtab *sep;
490 
491 	timingout = 0;
492 	for (sep = servtab; sep; sep = sep->se_next)
493 		if (sep->se_fd == -1)
494 			setup(sep);
495 }
496 
497 setup(sep)
498 	register struct servtab *sep;
499 {
500 	int on = 1;
501 
502 	if ((sep->se_fd = socket(AF_INET, sep->se_socktype, 0)) < 0) {
503 		syslog(LOG_ERR, "%s/%s: socket: %m",
504 		    sep->se_service, sep->se_proto);
505 		return;
506 	}
507 #define	turnon(fd, opt) \
508 setsockopt(fd, SOL_SOCKET, opt, (char *)&on, sizeof (on))
509 	if (strcmp(sep->se_proto, "tcp") == 0 && (options & SO_DEBUG) &&
510 	    turnon(sep->se_fd, SO_DEBUG) < 0)
511 		syslog(LOG_ERR, "setsockopt (SO_DEBUG): %m");
512 	if (turnon(sep->se_fd, SO_REUSEADDR) < 0)
513 		syslog(LOG_ERR, "setsockopt (SO_REUSEADDR): %m");
514 #undef turnon
515 	if (bind(sep->se_fd, &sep->se_ctrladdr,
516 	    sizeof (sep->se_ctrladdr)) < 0) {
517 		syslog(LOG_ERR, "%s/%s: bind: %m",
518 		    sep->se_service, sep->se_proto);
519 		(void) close(sep->se_fd);
520 		sep->se_fd = -1;
521 		if (!timingout) {
522 			timingout = 1;
523 			alarm(RETRYTIME);
524 		}
525 		return;
526 	}
527 	if (sep->se_socktype == SOCK_STREAM)
528 		listen(sep->se_fd, 10);
529 	FD_SET(sep->se_fd, &allsock);
530 	nsock++;
531 	if (sep->se_fd > maxsock)
532 		maxsock = sep->se_fd;
533 }
534 
535 struct servtab *
536 enter(cp)
537 	struct servtab *cp;
538 {
539 	register struct servtab *sep;
540 	long omask;
541 
542 	sep = (struct servtab *)malloc(sizeof (*sep));
543 	if (sep == (struct servtab *)0) {
544 		syslog(LOG_ERR, "Out of memory.");
545 		exit(-1);
546 	}
547 	*sep = *cp;
548 	sep->se_fd = -1;
549 	omask = sigblock(SIGBLOCK);
550 	sep->se_next = servtab;
551 	servtab = sep;
552 	sigsetmask(omask);
553 	return (sep);
554 }
555 
556 FILE	*fconfig = NULL;
557 struct	servtab serv;
558 char	line[256];
559 char	*skip(), *nextline();
560 
561 setconfig()
562 {
563 
564 	if (fconfig != NULL) {
565 		fseek(fconfig, 0L, L_SET);
566 		return (1);
567 	}
568 	fconfig = fopen(CONFIG, "r");
569 	return (fconfig != NULL);
570 }
571 
572 endconfig()
573 {
574 	if (fconfig) {
575 		(void) fclose(fconfig);
576 		fconfig = NULL;
577 	}
578 }
579 
580 struct servtab *
581 getconfigent()
582 {
583 	register struct servtab *sep = &serv;
584 	int argc;
585 	char *cp, *arg, *strdup();
586 
587 more:
588 	while ((cp = nextline(fconfig)) && *cp == '#')
589 		;
590 	if (cp == NULL)
591 		return ((struct servtab *)0);
592 	sep->se_service = strdup(skip(&cp));
593 	arg = skip(&cp);
594 	if (strcmp(arg, "stream") == 0)
595 		sep->se_socktype = SOCK_STREAM;
596 	else if (strcmp(arg, "dgram") == 0)
597 		sep->se_socktype = SOCK_DGRAM;
598 	else if (strcmp(arg, "rdm") == 0)
599 		sep->se_socktype = SOCK_RDM;
600 	else if (strcmp(arg, "seqpacket") == 0)
601 		sep->se_socktype = SOCK_SEQPACKET;
602 	else if (strcmp(arg, "raw") == 0)
603 		sep->se_socktype = SOCK_RAW;
604 	else
605 		sep->se_socktype = -1;
606 	sep->se_proto = strdup(skip(&cp));
607 	arg = skip(&cp);
608 	sep->se_wait = strcmp(arg, "wait") == 0;
609 	sep->se_user = strdup(skip(&cp));
610 	sep->se_server = strdup(skip(&cp));
611 	if (strcmp(sep->se_server, "internal") == 0) {
612 		register struct biltin *bi;
613 
614 		for (bi = biltins; bi->bi_service; bi++)
615 			if (bi->bi_socktype == sep->se_socktype &&
616 			    strcmp(bi->bi_service, sep->se_service) == 0)
617 				break;
618 		if (bi->bi_service == 0) {
619 			syslog(LOG_ERR, "internal service %s unknown\n",
620 				sep->se_service);
621 			goto more;
622 		}
623 		sep->se_bi = bi;
624 		sep->se_wait = bi->bi_wait;
625 	} else
626 		sep->se_bi = NULL;
627 	argc = 0;
628 	for (arg = skip(&cp); cp; arg = skip(&cp))
629 		if (argc < MAXARGV)
630 			sep->se_argv[argc++] = strdup(arg);
631 	while (argc <= MAXARGV)
632 		sep->se_argv[argc++] = NULL;
633 	return (sep);
634 }
635 
636 freeconfig(cp)
637 	register struct servtab *cp;
638 {
639 	int i;
640 
641 	if (cp->se_service)
642 		free(cp->se_service);
643 	if (cp->se_proto)
644 		free(cp->se_proto);
645 	if (cp->se_user)
646 		free(cp->se_user);
647 	if (cp->se_server)
648 		free(cp->se_server);
649 	for (i = 0; i < MAXARGV; i++)
650 		if (cp->se_argv[i])
651 			free(cp->se_argv[i]);
652 }
653 
654 char *
655 skip(cpp)
656 	char **cpp;
657 {
658 	register char *cp = *cpp;
659 	char *start;
660 
661 again:
662 	while (*cp == ' ' || *cp == '\t')
663 		cp++;
664 	if (*cp == '\0') {
665 		char c;
666 
667 		c = getc(fconfig);
668 		(void) ungetc(c, fconfig);
669 		if (c == ' ' || c == '\t')
670 			if (cp = nextline(fconfig))
671 				goto again;
672 		*cpp = (char *)0;
673 		return ((char *)0);
674 	}
675 	start = cp;
676 	while (*cp && *cp != ' ' && *cp != '\t')
677 		cp++;
678 	if (*cp != '\0')
679 		*cp++ = '\0';
680 	*cpp = cp;
681 	return (start);
682 }
683 
684 char *
685 nextline(fd)
686 	FILE *fd;
687 {
688 	char *cp;
689 
690 	if (fgets(line, sizeof (line), fd) == NULL)
691 		return ((char *)0);
692 	cp = index(line, '\n');
693 	if (cp)
694 		*cp = '\0';
695 	return (line);
696 }
697 
698 char *
699 strdup(cp)
700 	char *cp;
701 {
702 	char *new;
703 
704 	if (cp == NULL)
705 		cp = "";
706 	new = malloc((unsigned)(strlen(cp) + 1));
707 	if (new == (char *)0) {
708 		syslog(LOG_ERR, "Out of memory.");
709 		exit(-1);
710 	}
711 	(void)strcpy(new, cp);
712 	return (new);
713 }
714 
715 setproctitle(a, s)
716 	char *a;
717 	int s;
718 {
719 	int size;
720 	register char *cp;
721 	struct sockaddr_in sin;
722 	char buf[80];
723 
724 	cp = Argv[0];
725 	size = sizeof(sin);
726 	if (getpeername(s, &sin, &size) == 0)
727 		(void) sprintf(buf, "-%s [%s]", a, inet_ntoa(sin.sin_addr));
728 	else
729 		(void) sprintf(buf, "-%s", a);
730 	strncpy(cp, buf, LastArg - cp);
731 	cp += strlen(cp);
732 	while (cp < LastArg)
733 		*cp++ = ' ';
734 }
735 
736 /*
737  * Internet services provided internally by inetd:
738  */
739 #define	BUFSIZE	4096
740 
741 /* ARGSUSED */
742 echo_stream(s, sep)		/* Echo service -- echo data back */
743 	int s;
744 	struct servtab *sep;
745 {
746 	char buffer[BUFSIZE];
747 	int i;
748 
749 	setproctitle(sep->se_service, s);
750 	while ((i = read(s, buffer, sizeof(buffer))) > 0 &&
751 	    write(s, buffer, i) > 0)
752 		;
753 	exit(0);
754 }
755 
756 /* ARGSUSED */
757 echo_dg(s, sep)			/* Echo service -- echo data back */
758 	int s;
759 	struct servtab *sep;
760 {
761 	char buffer[BUFSIZE];
762 	int i, size;
763 	struct sockaddr sa;
764 
765 	size = sizeof(sa);
766 	if ((i = recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size)) < 0)
767 		return;
768 	(void) sendto(s, buffer, i, 0, &sa, sizeof(sa));
769 }
770 
771 /* ARGSUSED */
772 discard_stream(s, sep)		/* Discard service -- ignore data */
773 	int s;
774 	struct servtab *sep;
775 {
776 	char buffer[BUFSIZE];
777 
778 	setproctitle(sep->se_service, s);
779 	while (1) {
780 		while (read(s, buffer, sizeof(buffer)) > 0)
781 			;
782 		if (errno != EINTR)
783 			break;
784 	}
785 	exit(0);
786 }
787 
788 /* ARGSUSED */
789 discard_dg(s, sep)		/* Discard service -- ignore data */
790 	int s;
791 	struct servtab *sep;
792 {
793 	char buffer[BUFSIZE];
794 
795 	(void) read(s, buffer, sizeof(buffer));
796 }
797 
798 #include <ctype.h>
799 #define LINESIZ 72
800 char ring[128];
801 char *endring;
802 
803 initring()
804 {
805 	register int i;
806 
807 	endring = ring;
808 
809 	for (i = 0; i <= 128; ++i)
810 		if (isprint(i))
811 			*endring++ = i;
812 }
813 
814 /* ARGSUSED */
815 chargen_stream(s, sep)		/* Character generator */
816 	int s;
817 	struct servtab *sep;
818 {
819 	register char *rs;
820 	int len;
821 	char text[LINESIZ+2];
822 
823 	setproctitle(sep->se_service, s);
824 
825 	if (!endring) {
826 		initring();
827 		rs = ring;
828 	}
829 
830 	text[LINESIZ] = '\r';
831 	text[LINESIZ + 1] = '\n';
832 	for (rs = ring;;) {
833 		if ((len = endring - rs) >= LINESIZ)
834 			bcopy(rs, text, LINESIZ);
835 		else {
836 			bcopy(rs, text, len);
837 			bcopy(ring, text + len, LINESIZ - len);
838 		}
839 		if (++rs == endring)
840 			rs = ring;
841 		if (write(s, text, sizeof(text)) != sizeof(text))
842 			break;
843 	}
844 	exit(0);
845 }
846 
847 /* ARGSUSED */
848 chargen_dg(s, sep)		/* Character generator */
849 	int s;
850 	struct servtab *sep;
851 {
852 	struct sockaddr sa;
853 	static char *rs;
854 	int len, size;
855 	char text[LINESIZ+2];
856 
857 	if (endring == 0) {
858 		initring();
859 		rs = ring;
860 	}
861 
862 	size = sizeof(sa);
863 	if (recvfrom(s, text, sizeof(text), 0, &sa, &size) < 0)
864 		return;
865 
866 	if ((len = endring - rs) >= LINESIZ)
867 		bcopy(rs, text, LINESIZ);
868 	else {
869 		bcopy(rs, text, len);
870 		bcopy(ring, text + len, LINESIZ - len);
871 	}
872 	if (++rs == endring)
873 		rs = ring;
874 	text[LINESIZ] = '\r';
875 	text[LINESIZ + 1] = '\n';
876 	(void) sendto(s, text, sizeof(text), 0, &sa, sizeof(sa));
877 }
878 
879 /*
880  * Return a machine readable date and time, in the form of the
881  * number of seconds since midnight, Jan 1, 1900.  Since gettimeofday
882  * returns the number of seconds since midnight, Jan 1, 1970,
883  * we must add 2208988800 seconds to this figure to make up for
884  * some seventy years Bell Labs was asleep.
885  */
886 
887 long
888 machtime()
889 {
890 	struct timeval tv;
891 
892 	if (gettimeofday(&tv, (struct timezone *)0) < 0) {
893 		fprintf(stderr, "Unable to get time of day\n");
894 		return (0L);
895 	}
896 	return (htonl((long)tv.tv_sec + 2208988800));
897 }
898 
899 /* ARGSUSED */
900 machtime_stream(s, sep)
901 	int s;
902 	struct servtab *sep;
903 {
904 	long result;
905 
906 	result = machtime();
907 	(void) write(s, (char *) &result, sizeof(result));
908 }
909 
910 /* ARGSUSED */
911 machtime_dg(s, sep)
912 	int s;
913 	struct servtab *sep;
914 {
915 	long result;
916 	struct sockaddr sa;
917 	int size;
918 
919 	size = sizeof(sa);
920 	if (recvfrom(s, (char *)&result, sizeof(result), 0, &sa, &size) < 0)
921 		return;
922 	result = machtime();
923 	(void) sendto(s, (char *) &result, sizeof(result), 0, &sa, sizeof(sa));
924 }
925 
926 /* ARGSUSED */
927 daytime_stream(s, sep)		/* Return human-readable time of day */
928 	int s;
929 	struct servtab *sep;
930 {
931 	char buffer[256];
932 	time_t time(), clock;
933 	char *ctime();
934 
935 	clock = time((time_t *) 0);
936 
937 	(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
938 	(void) write(s, buffer, strlen(buffer));
939 }
940 
941 /* ARGSUSED */
942 daytime_dg(s, sep)		/* Return human-readable time of day */
943 	int s;
944 	struct servtab *sep;
945 {
946 	char buffer[256];
947 	time_t time(), clock;
948 	struct sockaddr sa;
949 	int size;
950 	char *ctime();
951 
952 	clock = time((time_t *) 0);
953 
954 	size = sizeof(sa);
955 	if (recvfrom(s, buffer, sizeof(buffer), 0, &sa, &size) < 0)
956 		return;
957 	(void) sprintf(buffer, "%.24s\r\n", ctime(&clock));
958 	(void) sendto(s, buffer, strlen(buffer), 0, &sa, sizeof(sa));
959 }
960 
961 /*
962  * print_service:
963  *	Dump relevant information to stderr
964  */
965 print_service(action, sep)
966 	char *action;
967 	struct servtab *sep;
968 {
969 	fprintf(stderr,
970 	    "%s: %s proto=%s, wait=%d, user=%s builtin=%x server=%s\n",
971 	    action, sep->se_service, sep->se_proto,
972 	    sep->se_wait, sep->se_user, (int)sep->se_bi, sep->se_server);
973 }
974