source: MondoRescue/branches/stable/mindi-busybox/networking/telnet.c@ 821

Last change on this file since 821 was 821, checked in by Bruno Cornec, 18 years ago

Addition of busybox 1.2.1 as a mindi-busybox new package
This should avoid delivering binary files in mindi not built there (Fedora and Debian are quite serious about that)
File size: 13.1 KB
Line 
1/* vi: set sw=4 ts=4: */
2/*
3 * telnet implementation for busybox
4 *
5 * Author: Tomi Ollila <too@iki.fi>
6 * Copyright (C) 1994-2000 by Tomi Ollila
7 *
8 * Created: Thu Apr 7 13:29:41 1994 too
9 * Last modified: Fri Jun 9 14:34:24 2000 too
10 *
11 * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
12 *
13 * HISTORY
14 * Revision 3.1 1994/04/17 11:31:54 too
15 * initial revision
16 * Modified 2000/06/13 for inclusion into BusyBox by Erik Andersen <andersen@codepoet.org>
17 * Modified 2001/05/07 to add ability to pass TTYPE to remote host by Jim McQuillan
18 * <jam@ltsp.org>
19 * Modified 2004/02/11 to add ability to pass the USER variable to remote host
20 * by Fernando Silveira <swrh@gmx.net>
21 *
22 */
23
24#include <termios.h>
25#include <unistd.h>
26#include <errno.h>
27#include <stdlib.h>
28#include <stdarg.h>
29#include <string.h>
30#include <signal.h>
31#include <arpa/telnet.h>
32#include <sys/types.h>
33#include <sys/socket.h>
34#include <netinet/in.h>
35#include "busybox.h"
36
37#if 0
38enum { DOTRACE = 1 };
39#endif
40
41#ifdef DOTRACE
42#include <arpa/inet.h> /* for inet_ntoa()... */
43#define TRACE(x, y) do { if (x) printf y; } while (0)
44#else
45#define TRACE(x, y)
46#endif
47
48#define DATABUFSIZE 128
49#define IACBUFSIZE 128
50
51enum {
52 CHM_TRY = 0,
53 CHM_ON = 1,
54 CHM_OFF = 2,
55
56 UF_ECHO = 0x01,
57 UF_SGA = 0x02,
58
59 TS_0 = 1,
60 TS_IAC = 2,
61 TS_OPT = 3,
62 TS_SUB1 = 4,
63 TS_SUB2 = 5,
64};
65
66#define WriteCS(fd, str) write(fd, str, sizeof str -1)
67
68typedef unsigned char byte;
69
70/* use globals to reduce size ??? */ /* test this hypothesis later */
71static struct Globalvars {
72 int netfd; /* console fd:s are 0 and 1 (and 2) */
73 /* same buffer used both for network and console read/write */
74 char buf[DATABUFSIZE]; /* allocating so static size is smaller */
75 byte telstate; /* telnet negotiation state from network input */
76 byte telwish; /* DO, DONT, WILL, WONT */
77 byte charmode;
78 byte telflags;
79 byte gotsig;
80 byte do_termios;
81 /* buffer to handle telnet negotiations */
82 char iacbuf[IACBUFSIZE];
83 short iaclen; /* could even use byte */
84 struct termios termios_def;
85 struct termios termios_raw;
86} G;
87
88#define xUSE_GLOBALVAR_PTR /* xUSE... -> don't use :D (makes smaller code) */
89
90#ifdef USE_GLOBALVAR_PTR
91struct Globalvars * Gptr;
92#define G (*Gptr)
93#endif
94
95static inline void iacflush(void)
96{
97 write(G.netfd, G.iacbuf, G.iaclen);
98 G.iaclen = 0;
99}
100
101/* Function prototypes */
102static void rawmode(void);
103static void cookmode(void);
104static void do_linemode(void);
105static void will_charmode(void);
106static void telopt(byte c);
107static int subneg(byte c);
108
109/* Some globals */
110static int one = 1;
111
112#ifdef CONFIG_FEATURE_TELNET_TTYPE
113static char *ttype;
114#endif
115
116#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
117static const char *autologin;
118#endif
119
120#ifdef CONFIG_FEATURE_AUTOWIDTH
121static int win_width, win_height;
122#endif
123
124static void doexit(int ev)
125{
126 cookmode();
127 exit(ev);
128}
129
130static void conescape(void)
131{
132 char b;
133
134 if (G.gotsig) /* came from line mode... go raw */
135 rawmode();
136
137 WriteCS(1, "\r\nConsole escape. Commands are:\r\n\n"
138 " l go to line mode\r\n"
139 " c go to character mode\r\n"
140 " z suspend telnet\r\n"
141 " e exit telnet\r\n");
142
143 if (read(0, &b, 1) <= 0)
144 doexit(1);
145
146 switch (b)
147 {
148 case 'l':
149 if (!G.gotsig)
150 {
151 do_linemode();
152 goto rrturn;
153 }
154 break;
155 case 'c':
156 if (G.gotsig)
157 {
158 will_charmode();
159 goto rrturn;
160 }
161 break;
162 case 'z':
163 cookmode();
164 kill(0, SIGTSTP);
165 rawmode();
166 break;
167 case 'e':
168 doexit(0);
169 }
170
171 WriteCS(1, "continuing...\r\n");
172
173 if (G.gotsig)
174 cookmode();
175
176 rrturn:
177 G.gotsig = 0;
178
179}
180static void handlenetoutput(int len)
181{
182 /* here we could do smart tricks how to handle 0xFF:s in output
183 * stream like writing twice every sequence of FF:s (thus doing
184 * many write()s. But I think interactive telnet application does
185 * not need to be 100% 8-bit clean, so changing every 0xff:s to
186 * 0x7f:s
187 *
188 * 2002-mar-21, Przemyslaw Czerpak (druzus@polbox.com)
189 * I don't agree.
190 * first - I cannot use programs like sz/rz
191 * second - the 0x0D is sent as one character and if the next
192 * char is 0x0A then it's eaten by a server side.
193 * third - whay doy you have to make 'many write()s'?
194 * I don't understand.
195 * So I implemented it. It's realy useful for me. I hope that
196 * others people will find it interesting to.
197 */
198
199 int i, j;
200 byte * p = (byte*)G.buf;
201 byte outbuf[4*DATABUFSIZE];
202
203 for (i = len, j = 0; i > 0; i--, p++)
204 {
205 if (*p == 0x1d)
206 {
207 conescape();
208 return;
209 }
210 outbuf[j++] = *p;
211 if (*p == 0xff)
212 outbuf[j++] = 0xff;
213 else if (*p == 0x0d)
214 outbuf[j++] = 0x00;
215 }
216 if (j > 0 )
217 write(G.netfd, outbuf, j);
218}
219
220
221static void handlenetinput(int len)
222{
223 int i;
224 int cstart = 0;
225
226 for (i = 0; i < len; i++)
227 {
228 byte c = G.buf[i];
229
230 if (G.telstate == 0) /* most of the time state == 0 */
231 {
232 if (c == IAC)
233 {
234 cstart = i;
235 G.telstate = TS_IAC;
236 }
237 }
238 else
239 switch (G.telstate)
240 {
241 case TS_0:
242 if (c == IAC)
243 G.telstate = TS_IAC;
244 else
245 G.buf[cstart++] = c;
246 break;
247
248 case TS_IAC:
249 if (c == IAC) /* IAC IAC -> 0xFF */
250 {
251 G.buf[cstart++] = c;
252 G.telstate = TS_0;
253 break;
254 }
255 /* else */
256 switch (c)
257 {
258 case SB:
259 G.telstate = TS_SUB1;
260 break;
261 case DO:
262 case DONT:
263 case WILL:
264 case WONT:
265 G.telwish = c;
266 G.telstate = TS_OPT;
267 break;
268 default:
269 G.telstate = TS_0; /* DATA MARK must be added later */
270 }
271 break;
272 case TS_OPT: /* WILL, WONT, DO, DONT */
273 telopt(c);
274 G.telstate = TS_0;
275 break;
276 case TS_SUB1: /* Subnegotiation */
277 case TS_SUB2: /* Subnegotiation */
278 if (subneg(c))
279 G.telstate = TS_0;
280 break;
281 }
282 }
283 if (G.telstate)
284 {
285 if (G.iaclen) iacflush();
286 if (G.telstate == TS_0) G.telstate = 0;
287
288 len = cstart;
289 }
290
291 if (len)
292 write(1, G.buf, len);
293}
294
295
296/* ******************************* */
297
298static inline void putiac(int c)
299{
300 G.iacbuf[G.iaclen++] = c;
301}
302
303
304static void putiac2(byte wwdd, byte c)
305{
306 if (G.iaclen + 3 > IACBUFSIZE)
307 iacflush();
308
309 putiac(IAC);
310 putiac(wwdd);
311 putiac(c);
312}
313
314#if 0
315static void putiac1(byte c)
316{
317 if (G.iaclen + 2 > IACBUFSIZE)
318 iacflush();
319
320 putiac(IAC);
321 putiac(c);
322}
323#endif
324
325#ifdef CONFIG_FEATURE_TELNET_TTYPE
326static void putiac_subopt(byte c, char *str)
327{
328 int len = strlen(str) + 6; // ( 2 + 1 + 1 + strlen + 2 )
329
330 if (G.iaclen + len > IACBUFSIZE)
331 iacflush();
332
333 putiac(IAC);
334 putiac(SB);
335 putiac(c);
336 putiac(0);
337
338 while(*str)
339 putiac(*str++);
340
341 putiac(IAC);
342 putiac(SE);
343}
344#endif
345
346#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
347static void putiac_subopt_autologin(void)
348{
349 int len = strlen(autologin) + 6; // (2 + 1 + 1 + strlen + 2)
350 char *user = "USER";
351
352 if (G.iaclen + len > IACBUFSIZE)
353 iacflush();
354
355 putiac(IAC);
356 putiac(SB);
357 putiac(TELOPT_NEW_ENVIRON);
358 putiac(TELQUAL_IS);
359 putiac(NEW_ENV_VAR);
360
361 while(*user)
362 putiac(*user++);
363
364 putiac(NEW_ENV_VALUE);
365
366 while(*autologin)
367 putiac(*autologin++);
368
369 putiac(IAC);
370 putiac(SE);
371}
372#endif
373
374#ifdef CONFIG_FEATURE_AUTOWIDTH
375static void putiac_naws(byte c, int x, int y)
376{
377 if (G.iaclen + 9 > IACBUFSIZE)
378 iacflush();
379
380 putiac(IAC);
381 putiac(SB);
382 putiac(c);
383
384 putiac((x >> 8) & 0xff);
385 putiac(x & 0xff);
386 putiac((y >> 8) & 0xff);
387 putiac(y & 0xff);
388
389 putiac(IAC);
390 putiac(SE);
391}
392#endif
393
394/* void putiacstring (subneg strings) */
395
396/* ******************************* */
397
398static char const escapecharis[] = "\r\nEscape character is ";
399
400static void setConMode(void)
401{
402 if (G.telflags & UF_ECHO)
403 {
404 if (G.charmode == CHM_TRY) {
405 G.charmode = CHM_ON;
406 printf("\r\nEntering character mode%s'^]'.\r\n", escapecharis);
407 rawmode();
408 }
409 }
410 else
411 {
412 if (G.charmode != CHM_OFF) {
413 G.charmode = CHM_OFF;
414 printf("\r\nEntering line mode%s'^C'.\r\n", escapecharis);
415 cookmode();
416 }
417 }
418}
419
420/* ******************************* */
421
422static void will_charmode(void)
423{
424 G.charmode = CHM_TRY;
425 G.telflags |= (UF_ECHO | UF_SGA);
426 setConMode();
427
428 putiac2(DO, TELOPT_ECHO);
429 putiac2(DO, TELOPT_SGA);
430 iacflush();
431}
432
433static void do_linemode(void)
434{
435 G.charmode = CHM_TRY;
436 G.telflags &= ~(UF_ECHO | UF_SGA);
437 setConMode();
438
439 putiac2(DONT, TELOPT_ECHO);
440 putiac2(DONT, TELOPT_SGA);
441 iacflush();
442}
443
444/* ******************************* */
445
446static inline void to_notsup(char c)
447{
448 if (G.telwish == WILL) putiac2(DONT, c);
449 else if (G.telwish == DO) putiac2(WONT, c);
450}
451
452static inline void to_echo(void)
453{
454 /* if server requests ECHO, don't agree */
455 if (G.telwish == DO) { putiac2(WONT, TELOPT_ECHO); return; }
456 else if (G.telwish == DONT) return;
457
458 if (G.telflags & UF_ECHO)
459 {
460 if (G.telwish == WILL)
461 return;
462 }
463 else
464 if (G.telwish == WONT)
465 return;
466
467 if (G.charmode != CHM_OFF)
468 G.telflags ^= UF_ECHO;
469
470 if (G.telflags & UF_ECHO)
471 putiac2(DO, TELOPT_ECHO);
472 else
473 putiac2(DONT, TELOPT_ECHO);
474
475 setConMode();
476 WriteCS(1, "\r\n"); /* sudden modec */
477}
478
479static inline void to_sga(void)
480{
481 /* daemon always sends will/wont, client do/dont */
482
483 if (G.telflags & UF_SGA)
484 {
485 if (G.telwish == WILL)
486 return;
487 }
488 else
489 if (G.telwish == WONT)
490 return;
491
492 if ((G.telflags ^= UF_SGA) & UF_SGA) /* toggle */
493 putiac2(DO, TELOPT_SGA);
494 else
495 putiac2(DONT, TELOPT_SGA);
496
497 return;
498}
499
500#ifdef CONFIG_FEATURE_TELNET_TTYPE
501static inline void to_ttype(void)
502{
503 /* Tell server we will (or won't) do TTYPE */
504
505 if(ttype)
506 putiac2(WILL, TELOPT_TTYPE);
507 else
508 putiac2(WONT, TELOPT_TTYPE);
509
510 return;
511}
512#endif
513
514#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
515static inline void to_new_environ(void)
516{
517 /* Tell server we will (or will not) do AUTOLOGIN */
518
519 if (autologin)
520 putiac2(WILL, TELOPT_NEW_ENVIRON);
521 else
522 putiac2(WONT, TELOPT_NEW_ENVIRON);
523
524 return;
525}
526#endif
527
528#ifdef CONFIG_FEATURE_AUTOWIDTH
529static inline void to_naws(void)
530{
531 /* Tell server we will do NAWS */
532 putiac2(WILL, TELOPT_NAWS);
533 return;
534}
535#endif
536
537static void telopt(byte c)
538{
539 switch (c)
540 {
541 case TELOPT_ECHO: to_echo(); break;
542 case TELOPT_SGA: to_sga(); break;
543#ifdef CONFIG_FEATURE_TELNET_TTYPE
544 case TELOPT_TTYPE: to_ttype();break;
545#endif
546#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
547 case TELOPT_NEW_ENVIRON: to_new_environ(); break;
548#endif
549#ifdef CONFIG_FEATURE_AUTOWIDTH
550 case TELOPT_NAWS: to_naws();
551 putiac_naws(c, win_width, win_height);
552 break;
553#endif
554 default: to_notsup(c);
555 break;
556 }
557}
558
559
560/* ******************************* */
561
562/* subnegotiation -- ignore all (except TTYPE,NAWS) */
563
564static int subneg(byte c)
565{
566 switch (G.telstate)
567 {
568 case TS_SUB1:
569 if (c == IAC)
570 G.telstate = TS_SUB2;
571#ifdef CONFIG_FEATURE_TELNET_TTYPE
572 else
573 if (c == TELOPT_TTYPE)
574 putiac_subopt(TELOPT_TTYPE,ttype);
575#endif
576#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
577 else
578 if (c == TELOPT_NEW_ENVIRON)
579 putiac_subopt_autologin();
580#endif
581 break;
582 case TS_SUB2:
583 if (c == SE)
584 return TRUE;
585 G.telstate = TS_SUB1;
586 /* break; */
587 }
588 return FALSE;
589}
590
591/* ******************************* */
592
593static void fgotsig(int sig)
594{
595 G.gotsig = sig;
596}
597
598
599static void rawmode(void)
600{
601 if (G.do_termios) tcsetattr(0, TCSADRAIN, &G.termios_raw);
602}
603
604static void cookmode(void)
605{
606 if (G.do_termios) tcsetattr(0, TCSADRAIN, &G.termios_def);
607}
608
609int telnet_main(int argc, char** argv)
610{
611 int len;
612 struct sockaddr_in s_in;
613#ifdef USE_POLL
614 struct pollfd ufds[2];
615#else
616 fd_set readfds;
617 int maxfd;
618#endif
619
620#ifdef CONFIG_FEATURE_AUTOWIDTH
621 get_terminal_width_height(0, &win_width, &win_height);
622#endif
623
624#ifdef CONFIG_FEATURE_TELNET_TTYPE
625 ttype = getenv("TERM");
626#endif
627
628 memset(&G, 0, sizeof G);
629
630 if (tcgetattr(0, &G.termios_def) >= 0) {
631 G.do_termios = 1;
632
633 G.termios_raw = G.termios_def;
634 cfmakeraw(&G.termios_raw);
635 }
636
637 if (argc < 2)
638 bb_show_usage();
639
640#ifdef CONFIG_FEATURE_TELNET_AUTOLOGIN
641 if (1 & bb_getopt_ulflags(argc, argv, "al:", &autologin))
642 autologin = getenv("USER");
643
644 if (optind < argc) {
645 bb_lookup_host(&s_in, argv[optind++]);
646 s_in.sin_port = bb_lookup_port((optind < argc) ? argv[optind++] :
647 "telnet", "tcp", 23);
648 if (optind < argc)
649 bb_show_usage();
650 } else
651 bb_show_usage();
652#else
653 bb_lookup_host(&s_in, argv[1]);
654 s_in.sin_port = bb_lookup_port((argc == 3) ? argv[2] : "telnet", "tcp", 23);
655#endif
656
657 G.netfd = xconnect(&s_in);
658
659 setsockopt(G.netfd, SOL_SOCKET, SO_KEEPALIVE, &one, sizeof one);
660
661 signal(SIGINT, fgotsig);
662
663#ifdef USE_POLL
664 ufds[0].fd = 0; ufds[1].fd = G.netfd;
665 ufds[0].events = ufds[1].events = POLLIN;
666#else
667 FD_ZERO(&readfds);
668 FD_SET(0, &readfds);
669 FD_SET(G.netfd, &readfds);
670 maxfd = G.netfd + 1;
671#endif
672
673 while (1)
674 {
675#ifndef USE_POLL
676 fd_set rfds = readfds;
677
678 switch (select(maxfd, &rfds, NULL, NULL, NULL))
679#else
680 switch (poll(ufds, 2, -1))
681#endif
682 {
683 case 0:
684 /* timeout */
685 case -1:
686 /* error, ignore and/or log something, bay go to loop */
687 if (G.gotsig)
688 conescape();
689 else
690 sleep(1);
691 break;
692 default:
693
694#ifdef USE_POLL
695 if (ufds[0].revents) /* well, should check POLLIN, but ... */
696#else
697 if (FD_ISSET(0, &rfds))
698#endif
699 {
700 len = read(0, G.buf, DATABUFSIZE);
701
702 if (len <= 0)
703 doexit(0);
704
705 TRACE(0, ("Read con: %d\n", len));
706
707 handlenetoutput(len);
708 }
709
710#ifdef USE_POLL
711 if (ufds[1].revents) /* well, should check POLLIN, but ... */
712#else
713 if (FD_ISSET(G.netfd, &rfds))
714#endif
715 {
716 len = read(G.netfd, G.buf, DATABUFSIZE);
717
718 if (len <= 0)
719 {
720 WriteCS(1, "Connection closed by foreign host.\r\n");
721 doexit(1);
722 }
723 TRACE(0, ("Read netfd (%d): %d\n", G.netfd, len));
724
725 handlenetinput(len);
726 }
727 }
728 }
729}
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