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ea139302 PB |
1 | /* |
2 | * Copyright (c) 1989 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 | static char sccsid[] = "@(#)utility.c 5.1 (Berkeley) %G%"; | |
20 | #endif /* not lint */ | |
21 | ||
22 | ||
23 | #include "telnetd.h" | |
24 | ||
25 | /* | |
26 | * utility functions performing io related tasks | |
27 | */ | |
28 | ||
29 | /* | |
30 | * ttloop | |
31 | * | |
32 | * A small subroutine to flush the network output buffer, get some data | |
33 | * from the network, and pass it through the telnet state machine. We | |
34 | * also flush the pty input buffer (by dropping its data) if it becomes | |
35 | * too full. | |
36 | */ | |
37 | ||
38 | void | |
39 | ttloop() | |
40 | { | |
41 | void netflush(); | |
42 | ||
43 | if (nfrontp-nbackp) { | |
44 | netflush(); | |
45 | } | |
46 | ncc = read(net, netibuf, sizeof netibuf); | |
47 | if (ncc < 0) { | |
48 | syslog(LOG_INFO, "ttloop: read: %m\n"); | |
49 | exit(1); | |
50 | } else if (ncc == 0) { | |
51 | syslog(LOG_INFO, "ttloop: peer died: %m\n"); | |
52 | exit(1); | |
53 | } | |
54 | netip = netibuf; | |
55 | telrcv(); /* state machine */ | |
56 | if (ncc > 0) { | |
57 | pfrontp = pbackp = ptyobuf; | |
58 | telrcv(); | |
59 | } | |
60 | } /* end of ttloop */ | |
61 | ||
62 | /* | |
63 | * Check a descriptor to see if out of band data exists on it. | |
64 | */ | |
65 | stilloob(s) | |
66 | int s; /* socket number */ | |
67 | { | |
68 | static struct timeval timeout = { 0 }; | |
69 | fd_set excepts; | |
70 | int value; | |
71 | ||
72 | do { | |
73 | FD_ZERO(&excepts); | |
74 | FD_SET(s, &excepts); | |
75 | value = select(s+1, (fd_set *)0, (fd_set *)0, &excepts, &timeout); | |
76 | } while ((value == -1) && (errno == EINTR)); | |
77 | ||
78 | if (value < 0) { | |
79 | fatalperror(pty, "select"); | |
80 | } | |
81 | if (FD_ISSET(s, &excepts)) { | |
82 | return 1; | |
83 | } else { | |
84 | return 0; | |
85 | } | |
86 | } | |
87 | ||
88 | ptyflush() | |
89 | { | |
90 | int n; | |
91 | ||
92 | if ((n = pfrontp - pbackp) > 0) | |
93 | n = write(pty, pbackp, n); | |
94 | if (n < 0) | |
95 | return; | |
96 | pbackp += n; | |
97 | if (pbackp == pfrontp) | |
98 | pbackp = pfrontp = ptyobuf; | |
99 | } | |
100 | ||
101 | /* | |
102 | * nextitem() | |
103 | * | |
104 | * Return the address of the next "item" in the TELNET data | |
105 | * stream. This will be the address of the next character if | |
106 | * the current address is a user data character, or it will | |
107 | * be the address of the character following the TELNET command | |
108 | * if the current address is a TELNET IAC ("I Am a Command") | |
109 | * character. | |
110 | */ | |
111 | char * | |
112 | nextitem(current) | |
113 | char *current; | |
114 | { | |
115 | if ((*current&0xff) != IAC) { | |
116 | return current+1; | |
117 | } | |
118 | switch (*(current+1)&0xff) { | |
119 | case DO: | |
120 | case DONT: | |
121 | case WILL: | |
122 | case WONT: | |
123 | return current+3; | |
124 | case SB: /* loop forever looking for the SE */ | |
125 | { | |
126 | register char *look = current+2; | |
127 | ||
128 | for (;;) { | |
129 | if ((*look++&0xff) == IAC) { | |
130 | if ((*look++&0xff) == SE) { | |
131 | return look; | |
132 | } | |
133 | } | |
134 | } | |
135 | } | |
136 | default: | |
137 | return current+2; | |
138 | } | |
139 | } /* end of nextitem */ | |
140 | ||
141 | ||
142 | /* | |
143 | * netclear() | |
144 | * | |
145 | * We are about to do a TELNET SYNCH operation. Clear | |
146 | * the path to the network. | |
147 | * | |
148 | * Things are a bit tricky since we may have sent the first | |
149 | * byte or so of a previous TELNET command into the network. | |
150 | * So, we have to scan the network buffer from the beginning | |
151 | * until we are up to where we want to be. | |
152 | * | |
153 | * A side effect of what we do, just to keep things | |
154 | * simple, is to clear the urgent data pointer. The principal | |
155 | * caller should be setting the urgent data pointer AFTER calling | |
156 | * us in any case. | |
157 | */ | |
158 | netclear() | |
159 | { | |
160 | register char *thisitem, *next; | |
161 | char *good; | |
162 | #define wewant(p) ((nfrontp > p) && ((*p&0xff) == IAC) && \ | |
163 | ((*(p+1)&0xff) != EC) && ((*(p+1)&0xff) != EL)) | |
164 | ||
165 | thisitem = netobuf; | |
166 | ||
167 | while ((next = nextitem(thisitem)) <= nbackp) { | |
168 | thisitem = next; | |
169 | } | |
170 | ||
171 | /* Now, thisitem is first before/at boundary. */ | |
172 | ||
173 | good = netobuf; /* where the good bytes go */ | |
174 | ||
175 | while (nfrontp > thisitem) { | |
176 | if (wewant(thisitem)) { | |
177 | int length; | |
178 | ||
179 | next = thisitem; | |
180 | do { | |
181 | next = nextitem(next); | |
182 | } while (wewant(next) && (nfrontp > next)); | |
183 | length = next-thisitem; | |
184 | bcopy(thisitem, good, length); | |
185 | good += length; | |
186 | thisitem = next; | |
187 | } else { | |
188 | thisitem = nextitem(thisitem); | |
189 | } | |
190 | } | |
191 | ||
192 | nbackp = netobuf; | |
193 | nfrontp = good; /* next byte to be sent */ | |
194 | neturg = 0; | |
195 | } /* end of netclear */ | |
196 | ||
197 | /* | |
198 | * netflush | |
199 | * Send as much data as possible to the network, | |
200 | * handling requests for urgent data. | |
201 | */ | |
202 | void | |
203 | netflush() | |
204 | { | |
205 | int n; | |
206 | extern int not42; | |
207 | ||
208 | if ((n = nfrontp - nbackp) > 0) { | |
209 | /* | |
210 | * if no urgent data, or if the other side appears to be an | |
211 | * old 4.2 client (and thus unable to survive TCP urgent data), | |
212 | * write the entire buffer in non-OOB mode. | |
213 | */ | |
214 | if ((neturg == 0) || (not42 == 0)) { | |
215 | n = write(net, nbackp, n); /* normal write */ | |
216 | } else { | |
217 | n = neturg - nbackp; | |
218 | /* | |
219 | * In 4.2 (and 4.3) systems, there is some question about | |
220 | * what byte in a sendOOB operation is the "OOB" data. | |
221 | * To make ourselves compatible, we only send ONE byte | |
222 | * out of band, the one WE THINK should be OOB (though | |
223 | * we really have more the TCP philosophy of urgent data | |
224 | * rather than the Unix philosophy of OOB data). | |
225 | */ | |
226 | if (n > 1) { | |
227 | n = send(net, nbackp, n-1, 0); /* send URGENT all by itself */ | |
228 | } else { | |
229 | n = send(net, nbackp, n, MSG_OOB); /* URGENT data */ | |
230 | } | |
231 | } | |
232 | } | |
233 | if (n < 0) { | |
234 | if (errno == EWOULDBLOCK || errno == EINTR) | |
235 | return; | |
236 | cleanup(); | |
237 | } | |
238 | nbackp += n; | |
239 | if (nbackp >= neturg) { | |
240 | neturg = 0; | |
241 | } | |
242 | if (nbackp == nfrontp) { | |
243 | nbackp = nfrontp = netobuf; | |
244 | } | |
245 | return; | |
246 | } /* end of netflush */ | |
247 | ||
248 | ||
249 | /* | |
250 | * writenet | |
251 | * | |
252 | * Just a handy little function to write a bit of raw data to the net. | |
253 | * It will force a transmit of the buffer if necessary | |
254 | * | |
255 | * arguments | |
256 | * ptr - A pointer to a character string to write | |
257 | * len - How many bytes to write | |
258 | */ | |
259 | writenet(ptr, len) | |
260 | register char *ptr; | |
261 | register int len; | |
262 | { | |
263 | /* flush buffer if no room for new data) */ | |
264 | if ((&netobuf[BUFSIZ] - nfrontp) < len) { | |
265 | /* if this fails, don't worry, buffer is a little big */ | |
266 | netflush(); | |
267 | } | |
268 | ||
269 | bcopy(ptr, nfrontp, len); | |
270 | nfrontp += len; | |
271 | ||
272 | } /* end of writenet */ | |
273 | ||
274 | ||
275 | /* | |
276 | * miscellaneous functions doing a variety of little jobs follow ... | |
277 | */ | |
278 | ||
279 | ||
280 | fatal(f, msg) | |
281 | int f; | |
282 | char *msg; | |
283 | { | |
284 | char buf[BUFSIZ]; | |
285 | ||
286 | (void) sprintf(buf, "telnetd: %s.\r\n", msg); | |
287 | (void) write(f, buf, (int)strlen(buf)); | |
288 | sleep(1); /*XXX*/ | |
289 | exit(1); | |
290 | } | |
291 | ||
292 | fatalperror(f, msg) | |
293 | int f; | |
294 | char *msg; | |
295 | { | |
296 | char buf[BUFSIZ]; | |
297 | extern char *sys_errlist[]; | |
298 | ||
299 | (void) sprintf(buf, "%s: %s\r\n", msg, sys_errlist[errno]); | |
300 | fatal(f, buf); | |
301 | } | |
302 | ||
303 | char editedhost[32]; | |
304 | ||
305 | edithost(pat, host) | |
306 | register char *pat; | |
307 | register char *host; | |
308 | { | |
309 | register char *res = editedhost; | |
310 | char *strncpy(); | |
311 | ||
312 | if (!pat) | |
313 | pat = ""; | |
314 | while (*pat) { | |
315 | switch (*pat) { | |
316 | ||
317 | case '#': | |
318 | if (*host) | |
319 | host++; | |
320 | break; | |
321 | ||
322 | case '@': | |
323 | if (*host) | |
324 | *res++ = *host++; | |
325 | break; | |
326 | ||
327 | default: | |
328 | *res++ = *pat; | |
329 | break; | |
330 | } | |
331 | if (res == &editedhost[sizeof editedhost - 1]) { | |
332 | *res = '\0'; | |
333 | return; | |
334 | } | |
335 | pat++; | |
336 | } | |
337 | if (*host) | |
338 | (void) strncpy(res, host, | |
339 | sizeof editedhost - (res - editedhost) -1); | |
340 | else | |
341 | *res = '\0'; | |
342 | editedhost[sizeof editedhost - 1] = '\0'; | |
343 | } | |
344 | ||
345 | static char *putlocation; | |
346 | ||
347 | putstr(s) | |
348 | register char *s; | |
349 | { | |
350 | ||
351 | while (*s) | |
352 | putchr(*s++); | |
353 | } | |
354 | ||
355 | putchr(cc) | |
356 | { | |
357 | *putlocation++ = cc; | |
358 | } | |
359 | ||
360 | putf(cp, where) | |
361 | register char *cp; | |
362 | char *where; | |
363 | { | |
364 | char *slash; | |
365 | #ifndef NO_GETTYTAB | |
366 | char datebuffer[60]; | |
367 | #endif /* NO_GETTYTAB */ | |
368 | extern char *rindex(); | |
369 | ||
370 | putlocation = where; | |
371 | ||
372 | while (*cp) { | |
373 | if (*cp != '%') { | |
374 | putchr(*cp++); | |
375 | continue; | |
376 | } | |
377 | switch (*++cp) { | |
378 | ||
379 | case 't': | |
380 | slash = rindex(line, '/'); | |
381 | if (slash == (char *) 0) | |
382 | putstr(line); | |
383 | else | |
384 | putstr(&slash[1]); | |
385 | break; | |
386 | ||
387 | case 'h': | |
388 | putstr(editedhost); | |
389 | break; | |
390 | ||
391 | #ifndef NO_GETTYTAB | |
392 | case 'd': | |
393 | get_date(datebuffer); | |
394 | putstr(datebuffer); | |
395 | break; | |
396 | #endif /* NO_GETTYTAB */ | |
397 | ||
398 | case '%': | |
399 | putchr('%'); | |
400 | break; | |
401 | } | |
402 | cp++; | |
403 | } | |
404 | } | |
405 | ||
406 | /*ARGSUSED*/ | |
407 | #ifdef NO_GETTYTAB | |
408 | getent(cp, name) | |
409 | char *cp, *name; | |
410 | { | |
411 | return(0); | |
412 | } | |
413 | ||
414 | /*ARGSUSED*/ | |
415 | char * | |
416 | getstr(cp, cpp) | |
417 | char *cp, **cpp; | |
418 | { | |
419 | return(0); | |
420 | } | |
421 | #endif /* NO_GETTYTAB */ |