Commit | Line | Data |
---|---|---|
ac6e6727 | 1 | #ifndef lint |
16f092bf | 2 | static char sccsid[] = "@(#)telnetd.c 4.9 82/10/10"; |
ac6e6727 BJ |
3 | #endif |
4 | ||
66b878f6 BJ |
5 | /* |
6 | * Stripped-down telnet server. | |
7 | */ | |
8 | #include <stdio.h> | |
9 | #include <signal.h> | |
10 | #include <errno.h> | |
11 | #include <sgtty.h> | |
12 | #include <wait.h> | |
13 | #include <sys/types.h> | |
14 | #include <sys/socket.h> | |
15 | #include <net/in.h> | |
9f005877 | 16 | #include <netdb.h> |
66b878f6 BJ |
17 | #include "telnet.h" |
18 | ||
19 | #define INFINITY 10000000 | |
20 | #define BELL '\07' | |
66b878f6 BJ |
21 | |
22 | char hisopts[256]; | |
23 | char myopts[256]; | |
24 | ||
25 | char doopt[] = { IAC, DO, '%', 'c', 0 }; | |
26 | char dont[] = { IAC, DONT, '%', 'c', 0 }; | |
27 | char will[] = { IAC, WILL, '%', 'c', 0 }; | |
28 | char wont[] = { IAC, WONT, '%', 'c', 0 }; | |
29 | ||
30 | /* | |
31 | * I/O data buffers, pointers, and counters. | |
32 | */ | |
33 | char ptyibuf[BUFSIZ], *ptyip = ptyibuf; | |
34 | char ptyobuf[BUFSIZ], *pfrontp = ptyobuf, *pbackp = ptyobuf; | |
35 | char netibuf[BUFSIZ], *netip = netibuf; | |
9ef3087d | 36 | char netobuf[BUFSIZ], *nfrontp = netobuf, *nbackp = netobuf; |
66b878f6 BJ |
37 | int pcc, ncc; |
38 | ||
39 | int pty, net; | |
40 | int inter; | |
41 | extern int errno; | |
42 | char line[] = "/dev/ptyp0"; | |
43 | ||
9f005877 | 44 | struct sockaddr_in sin = { AF_INET }; |
75a2ff26 | 45 | int options = SO_ACCEPTCONN|SO_KEEPALIVE; |
66b878f6 BJ |
46 | |
47 | main(argc, argv) | |
48 | char *argv[]; | |
49 | { | |
50 | int s, pid; | |
51 | union wait status; | |
9f005877 | 52 | struct servent *sp; |
66b878f6 | 53 | |
9f005877 SL |
54 | sp = getservbyname("telnet", "tcp"); |
55 | if (sp == 0) { | |
56 | fprintf(stderr, "telnetd: tcp/telnet: unknown service\n"); | |
57 | exit(1); | |
58 | } | |
59 | sin.sin_port = sp->s_port; | |
66b878f6 BJ |
60 | argc--, argv++; |
61 | if (argc > 0 && !strcmp(argv[0], "-d")) | |
9f005877 SL |
62 | options |= SO_DEBUG, argc--, argv++; |
63 | if (argc > 0) { | |
64 | sin.sin_port = atoi(*argv); | |
65 | if (sin.sin_port <= 0) { | |
66 | fprintf(stderr, "telnetd: %s: bad port #\n", *argv); | |
67 | exit(1); | |
68 | } | |
69 | } | |
ac6e6727 | 70 | sin.sin_port = htons(sin.sin_port); |
16f092bf SL |
71 | #ifndef DEBUG |
72 | if (fork()) | |
73 | exit(0); | |
74 | for (s = 0; s < 10; s++) | |
75 | (void) close(s); | |
76 | (void) open("/", 0); | |
77 | (void) dup2(0, 1); | |
78 | (void) dup2(0, 2); | |
79 | { int tt = open("/dev/tty", 2); | |
80 | if (tt > 0) { | |
81 | ioctl(tt, TIOCNOTTY, 0); | |
82 | close(tt); | |
83 | } | |
84 | } | |
85 | #endif | |
66b878f6 BJ |
86 | for (;;) { |
87 | errno = 0; | |
88 | if ((s = socket(SOCK_STREAM, 0, &sin, options)) < 0) { | |
89 | perror("socket"); | |
90 | sleep(5); | |
91 | continue; | |
92 | } | |
93 | if (accept(s, 0) < 0) { | |
94 | perror("accept"); | |
95 | close(s); | |
96 | sleep(1); | |
97 | continue; | |
98 | } | |
99 | if ((pid = fork()) < 0) | |
100 | printf("Out of processes\n"); | |
101 | else if (pid == 0) | |
102 | doit(s); | |
103 | close(s); | |
104 | while (wait3(status, WNOHANG, 0) > 0) | |
105 | continue; | |
106 | } | |
107 | /*NOTREACHED*/ | |
108 | } | |
109 | ||
110 | int cleanup(); | |
111 | ||
112 | /* | |
113 | * Get a pty, scan input lines. | |
114 | */ | |
115 | doit(f) | |
116 | { | |
117 | char *cp = line; | |
118 | int i, p, cc, t; | |
119 | struct sgttyb b; | |
120 | ||
121 | for (i = 0; i < 16; i++) { | |
122 | cp[strlen("/dev/ptyp")] = "0123456789abcdef"[i]; | |
123 | p = open(cp, 2); | |
124 | if (p > 0) | |
125 | goto gotpty; | |
126 | } | |
127 | dup2(f, 1); | |
128 | printf("All network ports in use.\n"); | |
129 | exit(1); | |
130 | gotpty: | |
131 | dup2(f, 0); | |
132 | cp[strlen("/dev/")] = 't'; | |
133 | t = open("/dev/tty", 2); | |
134 | if (t >= 0) { | |
135 | ioctl(t, TIOCNOTTY, 0); | |
136 | close(t); | |
137 | } | |
138 | t = open(cp, 2); | |
139 | if (t < 0) { | |
140 | dup2(f, 2); | |
141 | perror(cp); | |
142 | exit(1); | |
143 | } | |
144 | ioctl(t, TIOCGETP, &b); | |
9ef3087d | 145 | b.sg_flags = CRMOD|XTABS|ANYP; |
66b878f6 | 146 | ioctl(t, TIOCSETP, &b); |
9ef3087d | 147 | ioctl(p, TIOCGETP, &b); |
da96b661 | 148 | b.sg_flags &= ~ECHO; |
9ef3087d | 149 | ioctl(p, TIOCSETP, &b); |
66b878f6 BJ |
150 | if ((i = fork()) < 0) { |
151 | dup2(f, 2); | |
152 | perror("fork"); | |
153 | exit(1); | |
154 | } | |
155 | if (i) | |
156 | telnet(f, p); | |
157 | close(f); | |
158 | close(p); | |
159 | dup2(t, 0); | |
160 | dup2(t, 1); | |
161 | dup2(t, 2); | |
162 | close(t); | |
163 | execl("/bin/login", "telnet-login", 0); | |
164 | perror("/bin/login"); | |
165 | exit(1); | |
166 | } | |
167 | ||
168 | /* | |
169 | * Main loop. Select from pty and network, and | |
170 | * hand data to telnet receiver finite state machine. | |
171 | */ | |
172 | telnet(f, p) | |
173 | { | |
174 | int on = 1; | |
175 | ||
176 | net = f, pty = p; | |
177 | ioctl(f, FIONBIO, &on); | |
178 | ioctl(p, FIONBIO, &on); | |
179 | signal(SIGTSTP, SIG_IGN); | |
180 | sigset(SIGCHLD, cleanup); | |
181 | ||
da96b661 SL |
182 | /* |
183 | * Request to do remote echo. | |
184 | */ | |
185 | dooption(TELOPT_ECHO); | |
186 | myopts[TELOPT_ECHO] = 1; | |
66b878f6 BJ |
187 | for (;;) { |
188 | int ibits = 0, obits = 0; | |
189 | register int c; | |
190 | ||
191 | /* | |
192 | * Never look for input if there's still | |
193 | * stuff in the corresponding output buffer | |
194 | */ | |
195 | if (nfrontp - nbackp) | |
196 | obits |= (1 << f); | |
197 | else | |
198 | ibits |= (1 << p); | |
199 | if (pfrontp - pbackp) | |
200 | obits |= (1 << p); | |
201 | else | |
202 | ibits |= (1 << f); | |
203 | if (ncc < 0 && pcc < 0) | |
204 | break; | |
205 | select(32, &ibits, &obits, INFINITY); | |
206 | if (ibits == 0 && obits == 0) { | |
207 | sleep(5); | |
208 | continue; | |
209 | } | |
210 | ||
211 | /* | |
212 | * Something to read from the network... | |
213 | */ | |
214 | if (ibits & (1 << f)) { | |
215 | ncc = read(f, netibuf, BUFSIZ); | |
216 | if (ncc < 0 && errno == EWOULDBLOCK) | |
217 | ncc = 0; | |
218 | else { | |
219 | if (ncc <= 0) | |
220 | break; | |
221 | netip = netibuf; | |
222 | } | |
223 | } | |
224 | ||
225 | /* | |
226 | * Something to read from the pty... | |
227 | */ | |
228 | if (ibits & (1 << p)) { | |
229 | pcc = read(p, ptyibuf, BUFSIZ); | |
230 | if (pcc < 0 && errno == EWOULDBLOCK) | |
231 | pcc = 0; | |
232 | else { | |
233 | if (pcc <= 0) | |
234 | break; | |
235 | ptyip = ptyibuf; | |
236 | } | |
237 | } | |
238 | ||
239 | while (pcc > 0) { | |
240 | if ((&netobuf[BUFSIZ] - nfrontp) < 2) | |
241 | break; | |
242 | c = *ptyip++ & 0377, pcc--; | |
243 | if (c == IAC) | |
244 | *nfrontp++ = c; | |
245 | *nfrontp++ = c; | |
246 | } | |
247 | if ((obits & (1 << f)) && (nfrontp - nbackp) > 0) | |
248 | netflush(); | |
249 | if (ncc > 0) | |
250 | telrcv(); | |
251 | if ((obits & (1 << p)) && (pfrontp - pbackp) > 0) | |
252 | ptyflush(); | |
253 | } | |
254 | cleanup(); | |
255 | } | |
256 | ||
257 | /* | |
258 | * State for recv fsm | |
259 | */ | |
260 | #define TS_DATA 0 /* base state */ | |
261 | #define TS_IAC 1 /* look for double IAC's */ | |
262 | #define TS_CR 2 /* CR-LF ->'s CR */ | |
263 | #define TS_BEGINNEG 3 /* throw away begin's... */ | |
264 | #define TS_ENDNEG 4 /* ...end's (suboption negotiation) */ | |
265 | #define TS_WILL 5 /* will option negotiation */ | |
266 | #define TS_WONT 6 /* wont " */ | |
267 | #define TS_DO 7 /* do " */ | |
268 | #define TS_DONT 8 /* dont " */ | |
269 | ||
270 | telrcv() | |
271 | { | |
272 | register int c; | |
273 | static int state = TS_DATA; | |
274 | struct sgttyb b; | |
275 | ||
276 | while (ncc > 0) { | |
277 | if ((&ptyobuf[BUFSIZ] - pfrontp) < 2) | |
278 | return; | |
279 | c = *netip++ & 0377, ncc--; | |
280 | switch (state) { | |
281 | ||
282 | case TS_DATA: | |
283 | if (c == IAC) { | |
284 | state = TS_IAC; | |
285 | break; | |
286 | } | |
287 | if (inter > 0) | |
288 | break; | |
289 | *pfrontp++ = c; | |
290 | if (!myopts[TELOPT_BINARY] && c == '\r') | |
291 | state = TS_CR; | |
292 | break; | |
293 | ||
294 | case TS_CR: | |
295 | if (c && c != '\n') | |
296 | *pfrontp++ = c; | |
297 | state = TS_DATA; | |
298 | break; | |
299 | ||
300 | case TS_IAC: | |
301 | switch (c) { | |
302 | ||
303 | /* | |
304 | * Send the process on the pty side an | |
305 | * interrupt. Do this with a NULL or | |
306 | * interrupt char; depending on the tty mode. | |
307 | */ | |
308 | case BREAK: | |
309 | case IP: | |
310 | interrupt(); | |
311 | break; | |
312 | ||
313 | /* | |
314 | * Are You There? | |
315 | */ | |
316 | case AYT: | |
317 | *pfrontp++ = BELL; | |
318 | break; | |
319 | ||
320 | /* | |
321 | * Erase Character and | |
322 | * Erase Line | |
323 | */ | |
324 | case EC: | |
325 | case EL: | |
326 | ptyflush(); /* half-hearted */ | |
327 | ioctl(pty, TIOCGETP, &b); | |
328 | *pfrontp++ = (c == EC) ? | |
329 | b.sg_erase : b.sg_kill; | |
330 | break; | |
331 | ||
332 | /* | |
333 | * Check for urgent data... | |
334 | */ | |
335 | case DM: | |
336 | break; | |
337 | ||
338 | /* | |
339 | * Begin option subnegotiation... | |
340 | */ | |
341 | case SB: | |
342 | state = TS_BEGINNEG; | |
343 | continue; | |
344 | ||
345 | case WILL: | |
346 | case WONT: | |
347 | case DO: | |
348 | case DONT: | |
349 | state = TS_WILL + (c - WILL); | |
350 | continue; | |
351 | ||
352 | case IAC: | |
353 | *pfrontp++ = c; | |
354 | break; | |
355 | } | |
356 | state = TS_DATA; | |
357 | break; | |
358 | ||
359 | case TS_BEGINNEG: | |
360 | if (c == IAC) | |
361 | state = TS_ENDNEG; | |
362 | break; | |
363 | ||
364 | case TS_ENDNEG: | |
365 | state = c == SE ? TS_DATA : TS_BEGINNEG; | |
366 | break; | |
367 | ||
368 | case TS_WILL: | |
369 | if (!hisopts[c]) | |
370 | willoption(c); | |
371 | state = TS_DATA; | |
372 | continue; | |
373 | ||
374 | case TS_WONT: | |
375 | if (hisopts[c]) | |
376 | wontoption(c); | |
377 | state = TS_DATA; | |
378 | continue; | |
379 | ||
380 | case TS_DO: | |
381 | if (!myopts[c]) | |
382 | dooption(c); | |
383 | state = TS_DATA; | |
384 | continue; | |
385 | ||
386 | case TS_DONT: | |
387 | if (myopts[c]) { | |
388 | myopts[c] = 0; | |
389 | sprintf(nfrontp, wont, c); | |
da96b661 | 390 | nfrontp += sizeof (wont) - 2; |
66b878f6 BJ |
391 | } |
392 | state = TS_DATA; | |
393 | continue; | |
394 | ||
395 | default: | |
396 | printf("netser: panic state=%d\n", state); | |
397 | exit(1); | |
398 | } | |
399 | } | |
400 | } | |
401 | ||
402 | willoption(option) | |
403 | int option; | |
404 | { | |
405 | char *fmt; | |
406 | ||
407 | switch (option) { | |
408 | ||
409 | case TELOPT_BINARY: | |
410 | mode(RAW, 0); | |
411 | goto common; | |
412 | ||
413 | case TELOPT_ECHO: | |
414 | mode(0, ECHO|CRMOD); | |
415 | /*FALL THRU*/ | |
416 | ||
417 | case TELOPT_SGA: | |
418 | common: | |
419 | hisopts[option] = 1; | |
420 | fmt = doopt; | |
421 | break; | |
422 | ||
423 | case TELOPT_TM: | |
424 | fmt = dont; | |
425 | break; | |
426 | ||
427 | default: | |
428 | fmt = dont; | |
429 | break; | |
430 | } | |
13646f15 | 431 | sprintf(nfrontp, fmt, option); |
da96b661 | 432 | nfrontp += sizeof (dont) - 2; |
66b878f6 BJ |
433 | } |
434 | ||
435 | wontoption(option) | |
436 | int option; | |
437 | { | |
438 | char *fmt; | |
439 | ||
440 | switch (option) { | |
441 | ||
442 | case TELOPT_ECHO: | |
443 | mode(ECHO|CRMOD, 0); | |
444 | goto common; | |
445 | ||
446 | case TELOPT_BINARY: | |
447 | mode(0, RAW); | |
448 | /*FALL THRU*/ | |
449 | ||
450 | case TELOPT_SGA: | |
451 | common: | |
452 | hisopts[option] = 0; | |
453 | fmt = dont; | |
454 | break; | |
455 | ||
456 | default: | |
457 | fmt = dont; | |
458 | } | |
459 | sprintf(nfrontp, fmt, option); | |
da96b661 | 460 | nfrontp += sizeof (doopt) - 2; |
66b878f6 BJ |
461 | } |
462 | ||
463 | dooption(option) | |
464 | int option; | |
465 | { | |
466 | char *fmt; | |
467 | ||
468 | switch (option) { | |
469 | ||
470 | case TELOPT_TM: | |
471 | fmt = wont; | |
472 | break; | |
473 | ||
474 | case TELOPT_ECHO: | |
475 | mode(ECHO|CRMOD, 0); | |
476 | goto common; | |
477 | ||
478 | case TELOPT_BINARY: | |
479 | mode(RAW, 0); | |
480 | /*FALL THRU*/ | |
481 | ||
482 | case TELOPT_SGA: | |
483 | common: | |
484 | fmt = will; | |
485 | break; | |
486 | ||
487 | default: | |
488 | fmt = wont; | |
489 | break; | |
490 | } | |
491 | sprintf(nfrontp, fmt, option); | |
da96b661 | 492 | nfrontp += sizeof (doopt) - 2; |
66b878f6 BJ |
493 | } |
494 | ||
495 | mode(on, off) | |
496 | int on, off; | |
497 | { | |
498 | struct sgttyb b; | |
499 | ||
500 | ptyflush(); | |
501 | ioctl(pty, TIOCGETP, &b); | |
502 | b.sg_flags |= on; | |
503 | b.sg_flags &= ~off; | |
504 | ioctl(pty, TIOCSETP, &b); | |
505 | } | |
506 | ||
507 | /* | |
508 | * Send interrupt to process on other side of pty. | |
509 | * If it is in raw mode, just write NULL; | |
510 | * otherwise, write intr char. | |
511 | */ | |
512 | interrupt() | |
513 | { | |
514 | struct sgttyb b; | |
515 | struct tchars tchars; | |
516 | ||
517 | ptyflush(); /* half-hearted */ | |
518 | ioctl(pty, TIOCGETP, &b); | |
519 | if (b.sg_flags & RAW) { | |
520 | *pfrontp++ = '\0'; | |
521 | return; | |
522 | } | |
523 | *pfrontp++ = ioctl(pty, TIOCGETC, &tchars) < 0 ? | |
524 | '\177' : tchars.t_intrc; | |
525 | } | |
526 | ||
527 | ptyflush() | |
528 | { | |
529 | int n; | |
530 | ||
531 | if ((n = pfrontp - pbackp) > 0) | |
532 | n = write(pty, pbackp, n); | |
9f005877 SL |
533 | if (n < 0) |
534 | return; | |
66b878f6 BJ |
535 | pbackp += n; |
536 | if (pbackp == pfrontp) | |
537 | pbackp = pfrontp = ptyobuf; | |
538 | } | |
539 | ||
540 | netflush() | |
541 | { | |
542 | int n; | |
543 | ||
544 | if ((n = nfrontp - nbackp) > 0) | |
545 | n = write(net, nbackp, n); | |
9f005877 SL |
546 | if (n < 0) { |
547 | if (errno == EWOULDBLOCK) | |
548 | return; | |
549 | /* should blow this guy away... */ | |
550 | return; | |
551 | } | |
66b878f6 BJ |
552 | nbackp += n; |
553 | if (nbackp == nfrontp) | |
554 | nbackp = nfrontp = netobuf; | |
555 | } | |
556 | ||
557 | cleanup() | |
558 | { | |
559 | int how = 2; | |
560 | ||
561 | rmut(); | |
562 | vhangup(); | |
563 | ioctl(net, SIOCDONE, &how); | |
564 | kill(0, SIGKILL); | |
565 | exit(1); | |
566 | } | |
567 | ||
568 | #include <utmp.h> | |
569 | ||
570 | struct utmp wtmp; | |
571 | char wtmpf[] = "/usr/adm/wtmp"; | |
572 | char utmp[] = "/etc/utmp"; | |
da96b661 SL |
573 | #define SCPYN(a, b) strncpy(a, b, sizeof (a)) |
574 | #define SCMPN(a, b) strncmp(a, b, sizeof (a)) | |
66b878f6 BJ |
575 | |
576 | rmut() | |
577 | { | |
578 | register f; | |
579 | int found = 0; | |
580 | ||
581 | f = open(utmp, 2); | |
582 | if (f >= 0) { | |
da96b661 | 583 | while(read(f, (char *)&wtmp, sizeof (wtmp)) == sizeof (wtmp)) { |
66b878f6 BJ |
584 | if (SCMPN(wtmp.ut_line, line+5) || wtmp.ut_name[0]==0) |
585 | continue; | |
da96b661 | 586 | lseek(f, -(long)sizeof (wtmp), 1); |
66b878f6 BJ |
587 | SCPYN(wtmp.ut_name, ""); |
588 | time(&wtmp.ut_time); | |
da96b661 | 589 | write(f, (char *)&wtmp, sizeof (wtmp)); |
66b878f6 BJ |
590 | found++; |
591 | } | |
592 | close(f); | |
593 | } | |
594 | if (found) { | |
595 | f = open(wtmpf, 1); | |
596 | if (f >= 0) { | |
597 | SCPYN(wtmp.ut_line, line+5); | |
598 | SCPYN(wtmp.ut_name, ""); | |
599 | time(&wtmp.ut_time); | |
600 | lseek(f, (long)0, 2); | |
da96b661 | 601 | write(f, (char *)&wtmp, sizeof (wtmp)); |
66b878f6 BJ |
602 | close(f); |
603 | } | |
604 | } | |
605 | chmod(line, 0666); | |
606 | chown(line, 0, 0); | |
607 | line[strlen("/dev/")] = 'p'; | |
608 | chmod(line, 0666); | |
609 | chown(line, 0, 0); | |
610 | } |