Commit | Line | Data |
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60a17f4e JH |
1 | /* Functions for communicating with a remote tape drive. |
2 | Copyright (C) 1988, 1992 Free Software Foundation, Inc. | |
3 | ||
4 | This program is free software; you can redistribute it and/or modify | |
5 | it under the terms of the GNU General Public License as published by | |
6 | the Free Software Foundation; either version 2, or (at your option) | |
7 | any later version. | |
8 | ||
9 | This program is distributed in the hope that it will be useful, | |
10 | but WITHOUT ANY WARRANTY; without even the implied warranty of | |
11 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
12 | GNU General Public License for more details. | |
13 | ||
14 | You should have received a copy of the GNU General Public License | |
15 | along with this program; if not, write to the Free Software | |
16 | Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ | |
17 | ||
18 | /* The man page rmt(8) for /etc/rmt documents the remote mag tape | |
19 | protocol which rdump and rrestore use. Unfortunately, the man | |
20 | page is *WRONG*. The author of the routines I'm including originally | |
21 | wrote his code just based on the man page, and it didn't work, so he | |
22 | went to the rdump source to figure out why. The only thing he had to | |
23 | change was to check for the 'F' return code in addition to the 'E', | |
24 | and to separate the various arguments with \n instead of a space. I | |
25 | personally don't think that this is much of a problem, but I wanted to | |
26 | point it out. -- Arnold Robbins | |
27 | ||
28 | Originally written by Jeff Lee, modified some by Arnold Robbins. | |
29 | Redone as a library that can replace open, read, write, etc., by | |
30 | Fred Fish, with some additional work by Arnold Robbins. | |
31 | Modified to make all rmtXXX calls into macros for speed by Jay Fenlason. | |
32 | Use -DHAVE_NETDB_H for rexec code, courtesy of Dan Kegel, srs!dan. */ | |
33 | ||
34 | #include <stdio.h> | |
35 | #include <sys/types.h> | |
36 | #include <signal.h> | |
37 | ||
38 | #ifdef HAVE_SYS_MTIO_H | |
39 | #include <sys/ioctl.h> | |
40 | #include <sys/mtio.h> | |
41 | #endif | |
42 | ||
43 | #ifdef HAVE_NETDB_H | |
44 | #include <netdb.h> | |
45 | #endif | |
46 | ||
47 | #include <errno.h> | |
48 | #include <setjmp.h> | |
49 | #include <sys/stat.h> | |
50 | ||
51 | #ifndef errno | |
52 | extern int errno; | |
53 | #endif | |
54 | ||
55 | #ifdef HAVE_UNISTD_H | |
56 | #include <unistd.h> | |
57 | #endif | |
58 | #ifdef STDC_HEADERS | |
59 | #include <string.h> | |
60 | #include <stdlib.h> | |
61 | #endif | |
62 | ||
63 | /* Maximum size of a fully qualified host name. */ | |
64 | #define MAXHOSTLEN 257 | |
65 | ||
66 | /* Size of buffers for reading and writing commands to rmt. | |
67 | (An arbitrary limit.) */ | |
68 | #define CMDBUFSIZE 64 | |
69 | ||
70 | #ifndef RETSIGTYPE | |
71 | #define RETSIGTYPE void | |
72 | #endif | |
73 | ||
74 | /* Maximum number of simultaneous remote tape connections. | |
75 | (Another arbitrary limit.) */ | |
76 | #define MAXUNIT 4 | |
77 | ||
78 | /* Return the parent's read side of remote tape connection FILDES. */ | |
79 | #define READ(fildes) (from_rmt[fildes][0]) | |
80 | ||
81 | /* Return the parent's write side of remote tape connection FILDES. */ | |
82 | #define WRITE(fildes) (to_rmt[fildes][1]) | |
83 | ||
84 | /* The pipes for receiving data from remote tape drives. */ | |
85 | static int from_rmt[MAXUNIT][2] = | |
86 | {-1, -1, -1, -1, -1, -1, -1, -1}; | |
87 | ||
88 | /* The pipes for sending data to remote tape drives. */ | |
89 | static int to_rmt[MAXUNIT][2] = | |
90 | {-1, -1, -1, -1, -1, -1, -1, -1}; | |
91 | ||
92 | /* Temporary variable used by macros in rmt.h. */ | |
93 | char *__rmt_path; | |
94 | \f | |
95 | /* Close remote tape connection FILDES. */ | |
96 | ||
97 | static void | |
98 | _rmt_shutdown (fildes) | |
99 | int fildes; | |
100 | { | |
101 | close (READ (fildes)); | |
102 | close (WRITE (fildes)); | |
103 | READ (fildes) = -1; | |
104 | WRITE (fildes) = -1; | |
105 | } | |
106 | ||
107 | /* Attempt to perform the remote tape command specified in BUF | |
108 | on remote tape connection FILDES. | |
109 | Return 0 if successful, -1 on error. */ | |
110 | ||
111 | static int | |
112 | command (fildes, buf) | |
113 | int fildes; | |
114 | char *buf; | |
115 | { | |
116 | register int buflen; | |
117 | RETSIGTYPE (*pipe_handler) (); | |
118 | ||
119 | /* Save the current pipe handler and try to make the request. */ | |
120 | ||
121 | pipe_handler = signal (SIGPIPE, SIG_IGN); | |
122 | buflen = strlen (buf); | |
123 | if (write (WRITE (fildes), buf, buflen) == buflen) | |
124 | { | |
125 | signal (SIGPIPE, pipe_handler); | |
126 | return 0; | |
127 | } | |
128 | ||
129 | /* Something went wrong. Close down and go home. */ | |
130 | ||
131 | signal (SIGPIPE, pipe_handler); | |
132 | _rmt_shutdown (fildes); | |
133 | errno = EIO; | |
134 | return -1; | |
135 | } | |
136 | ||
137 | /* Read and return the status from remote tape connection FILDES. | |
138 | If an error occurred, return -1 and set errno. */ | |
139 | ||
140 | static int | |
141 | status (fildes) | |
142 | int fildes; | |
143 | { | |
144 | int i; | |
145 | char c, *cp; | |
146 | char buffer[CMDBUFSIZE]; | |
147 | ||
148 | /* Read the reply command line. */ | |
149 | ||
150 | for (i = 0, cp = buffer; i < CMDBUFSIZE; i++, cp++) | |
151 | { | |
152 | if (read (READ (fildes), cp, 1) != 1) | |
153 | { | |
154 | _rmt_shutdown (fildes); | |
155 | errno = EIO; | |
156 | return -1; | |
157 | } | |
158 | if (*cp == '\n') | |
159 | { | |
160 | *cp = '\0'; | |
161 | break; | |
162 | } | |
163 | } | |
164 | ||
165 | if (i == CMDBUFSIZE) | |
166 | { | |
167 | _rmt_shutdown (fildes); | |
168 | errno = EIO; | |
169 | return -1; | |
170 | } | |
171 | ||
172 | /* Check the return status. */ | |
173 | ||
174 | for (cp = buffer; *cp; cp++) | |
175 | if (*cp != ' ') | |
176 | break; | |
177 | ||
178 | if (*cp == 'E' || *cp == 'F') | |
179 | { | |
180 | errno = atoi (cp + 1); | |
181 | /* Skip the error message line. */ | |
182 | while (read (READ (fildes), &c, 1) == 1) | |
183 | if (c == '\n') | |
184 | break; | |
185 | ||
186 | if (*cp == 'F') | |
187 | _rmt_shutdown (fildes); | |
188 | ||
189 | return -1; | |
190 | } | |
191 | ||
192 | /* Check for mis-synced pipes. */ | |
193 | ||
194 | if (*cp != 'A') | |
195 | { | |
196 | _rmt_shutdown (fildes); | |
197 | errno = EIO; | |
198 | return -1; | |
199 | } | |
200 | ||
201 | /* Got an `A' (success) response. */ | |
202 | return atoi (cp + 1); | |
203 | } | |
204 | ||
205 | #ifdef HAVE_NETDB_H | |
206 | /* Execute /etc/rmt as user USER on remote system HOST using rexec. | |
207 | Return a file descriptor of a bidirectional socket for stdin and stdout. | |
208 | If USER is NULL, or an empty string, use the current username. | |
209 | ||
210 | By default, this code is not used, since it requires that | |
211 | the user have a .netrc file in his/her home directory, or that the | |
212 | application designer be willing to have rexec prompt for login and | |
213 | password info. This may be unacceptable, and .rhosts files for use | |
214 | with rsh are much more common on BSD systems. */ | |
215 | ||
216 | static int | |
217 | _rmt_rexec (host, user) | |
218 | char *host; | |
219 | char *user; | |
220 | { | |
221 | struct servent *rexecserv; | |
222 | int save_stdin = dup (fileno (stdin)); | |
223 | int save_stdout = dup (fileno (stdout)); | |
224 | int tape_fd; /* Return value. */ | |
225 | ||
226 | /* When using cpio -o < filename, stdin is no longer the tty. | |
227 | But the rexec subroutine reads the login and the passwd on stdin, | |
228 | to allow remote execution of the command. | |
229 | So, reopen stdin and stdout on /dev/tty before the rexec and | |
230 | give them back their original value after. */ | |
231 | if (freopen ("/dev/tty", "r", stdin) == NULL) | |
232 | freopen ("/dev/null", "r", stdin); | |
233 | if (freopen ("/dev/tty", "w", stdout) == NULL) | |
234 | freopen ("/dev/null", "w", stdout); | |
235 | ||
236 | rexecserv = getservbyname ("exec", "tcp"); | |
237 | if (NULL == rexecserv) | |
238 | { | |
239 | fprintf (stderr, "exec/tcp: service not available"); | |
240 | exit (1); | |
241 | } | |
242 | if (user != NULL && *user == '\0') | |
243 | user = NULL; | |
244 | tape_fd = rexec (&host, rexecserv->s_port, user, NULL, | |
245 | "/etc/rmt", (int *) NULL); | |
246 | fclose (stdin); | |
247 | fdopen (save_stdin, "r"); | |
248 | fclose (stdout); | |
249 | fdopen (save_stdout, "w"); | |
250 | ||
251 | return tape_fd; | |
252 | } | |
253 | ||
254 | #endif /* HAVE_NETDB_H */ | |
255 | ||
256 | /* Open a magtape device on the system specified in PATH, as the given user. | |
257 | PATH has the form `[user@]system:/dev/????'. | |
258 | If COMPAT is defined, it can also have the form `system[.user]:/dev/????'. | |
259 | ||
260 | OFLAG is O_RDONLY, O_WRONLY, etc. | |
261 | MODE is ignored; 0666 is always used. | |
262 | ||
263 | If successful, return the remote tape pipe number plus BIAS. | |
264 | On error, return -1. */ | |
265 | ||
266 | int | |
267 | __rmt_open (path, oflag, mode, bias) | |
268 | char *path; | |
269 | int oflag; | |
270 | int mode; | |
271 | int bias; | |
272 | { | |
273 | int i, rc; | |
274 | char buffer[CMDBUFSIZE]; /* Command buffer. */ | |
275 | char system[MAXHOSTLEN]; /* The remote host name. */ | |
276 | char device[CMDBUFSIZE]; /* The remote device name. */ | |
277 | char login[CMDBUFSIZE]; /* The remote user name. */ | |
278 | char *sys, *dev, *user; /* For copying into the above buffers. */ | |
279 | ||
280 | sys = system; | |
281 | dev = device; | |
282 | user = login; | |
283 | ||
284 | /* Find an unused pair of file descriptors. */ | |
285 | ||
286 | for (i = 0; i < MAXUNIT; i++) | |
287 | if (READ (i) == -1 && WRITE (i) == -1) | |
288 | break; | |
289 | ||
290 | if (i == MAXUNIT) | |
291 | { | |
292 | errno = EMFILE; | |
293 | return -1; | |
294 | } | |
295 | ||
296 | /* Pull apart the system and device, and optional user. | |
297 | Don't munge the original string. */ | |
298 | ||
299 | while (*path != '@' | |
300 | #ifdef COMPAT | |
301 | && *path != '.' | |
302 | #endif | |
303 | && *path != ':') | |
304 | { | |
305 | *sys++ = *path++; | |
306 | } | |
307 | *sys = '\0'; | |
308 | path++; | |
309 | ||
310 | if (*(path - 1) == '@') | |
311 | { | |
312 | /* Saw user part of user@host. Start over. */ | |
313 | strcpy (user, system); | |
314 | sys = system; | |
315 | while (*path != ':') | |
316 | { | |
317 | *sys++ = *path++; | |
318 | } | |
319 | *sys = '\0'; | |
320 | path++; | |
321 | } | |
322 | #ifdef COMPAT | |
323 | else if (*(path - 1) == '.') | |
324 | { | |
325 | while (*path != ':') | |
326 | { | |
327 | *user++ = *path++; | |
328 | } | |
329 | *user = '\0'; | |
330 | path++; | |
331 | } | |
332 | #endif | |
333 | else | |
334 | *user = '\0'; | |
335 | ||
336 | while (*path) | |
337 | { | |
338 | *dev++ = *path++; | |
339 | } | |
340 | *dev = '\0'; | |
341 | ||
342 | #ifdef HAVE_NETDB_H | |
343 | /* Execute the remote command using rexec. */ | |
344 | READ (i) = WRITE (i) = _rmt_rexec (system, login); | |
345 | if (READ (i) < 0) | |
346 | return -1; | |
347 | #else /* !HAVE_NETDB_H */ | |
348 | /* Set up the pipes for the `rsh' command, and fork. */ | |
349 | ||
350 | if (pipe (to_rmt[i]) == -1 || pipe (from_rmt[i]) == -1) | |
351 | return -1; | |
352 | ||
353 | rc = fork (); | |
354 | if (rc == -1) | |
355 | return -1; | |
356 | ||
357 | if (rc == 0) | |
358 | { | |
359 | /* Child. */ | |
360 | close (0); | |
361 | dup (to_rmt[i][0]); | |
362 | close (to_rmt[i][0]); | |
363 | close (to_rmt[i][1]); | |
364 | ||
365 | close (1); | |
366 | dup (from_rmt[i][1]); | |
367 | close (from_rmt[i][0]); | |
368 | close (from_rmt[i][1]); | |
369 | ||
370 | setuid (getuid ()); | |
371 | setgid (getgid ()); | |
372 | ||
373 | if (*login) | |
374 | { | |
375 | execl ("/usr/ucb/rsh", "rsh", system, "-l", login, | |
376 | "/etc/rmt", (char *) 0); | |
377 | execl ("/usr/bin/remsh", "remsh", system, "-l", login, | |
378 | "/etc/rmt", (char *) 0); | |
379 | execl ("/usr/bin/rsh", "rsh", system, "-l", login, | |
380 | "/etc/rmt", (char *) 0); | |
381 | execl ("/usr/bsd/rsh", "rsh", system, "-l", login, | |
382 | "/etc/rmt", (char *) 0); | |
383 | execl ("/usr/bin/nsh", "nsh", system, "-l", login, | |
384 | "/etc/rmt", (char *) 0); | |
385 | } | |
386 | else | |
387 | { | |
388 | execl ("/usr/ucb/rsh", "rsh", system, | |
389 | "/etc/rmt", (char *) 0); | |
390 | execl ("/usr/bin/remsh", "remsh", system, | |
391 | "/etc/rmt", (char *) 0); | |
392 | execl ("/usr/bin/rsh", "rsh", system, | |
393 | "/etc/rmt", (char *) 0); | |
394 | execl ("/usr/bsd/rsh", "rsh", system, | |
395 | "/etc/rmt", (char *) 0); | |
396 | execl ("/usr/bin/nsh", "nsh", system, | |
397 | "/etc/rmt", (char *) 0); | |
398 | } | |
399 | ||
400 | /* Bad problems if we get here. */ | |
401 | ||
402 | perror ("cannot execute remote shell"); | |
403 | _exit (1); | |
404 | } | |
405 | ||
406 | /* Parent. */ | |
407 | close (to_rmt[i][0]); | |
408 | close (from_rmt[i][1]); | |
409 | #endif /* !HAVE_NETDB_H */ | |
410 | ||
411 | /* Attempt to open the tape device. */ | |
412 | ||
413 | sprintf (buffer, "O%s\n%d\n", device, oflag); | |
414 | if (command (i, buffer) == -1 || status (i) == -1) | |
415 | return -1; | |
416 | ||
417 | return i + bias; | |
418 | } | |
419 | ||
420 | /* Close remote tape connection FILDES and shut down. | |
421 | Return 0 if successful, -1 on error. */ | |
422 | ||
423 | int | |
424 | __rmt_close (fildes) | |
425 | int fildes; | |
426 | { | |
427 | int rc; | |
428 | ||
429 | if (command (fildes, "C\n") == -1) | |
430 | return -1; | |
431 | ||
432 | rc = status (fildes); | |
433 | _rmt_shutdown (fildes); | |
434 | return rc; | |
435 | } | |
436 | ||
437 | /* Read up to NBYTE bytes into BUF from remote tape connection FILDES. | |
438 | Return the number of bytes read on success, -1 on error. */ | |
439 | ||
440 | int | |
441 | __rmt_read (fildes, buf, nbyte) | |
442 | int fildes; | |
443 | char *buf; | |
444 | unsigned int nbyte; | |
445 | { | |
446 | int rc, i; | |
447 | char buffer[CMDBUFSIZE]; | |
448 | ||
449 | sprintf (buffer, "R%d\n", nbyte); | |
450 | if (command (fildes, buffer) == -1 || (rc = status (fildes)) == -1) | |
451 | return -1; | |
452 | ||
453 | for (i = 0; i < rc; i += nbyte, buf += nbyte) | |
454 | { | |
455 | nbyte = read (READ (fildes), buf, rc - i); | |
456 | if (nbyte <= 0) | |
457 | { | |
458 | _rmt_shutdown (fildes); | |
459 | errno = EIO; | |
460 | return -1; | |
461 | } | |
462 | } | |
463 | ||
464 | return rc; | |
465 | } | |
466 | ||
467 | /* Write NBYTE bytes from BUF to remote tape connection FILDES. | |
468 | Return the number of bytes written on success, -1 on error. */ | |
469 | ||
470 | int | |
471 | __rmt_write (fildes, buf, nbyte) | |
472 | int fildes; | |
473 | char *buf; | |
474 | unsigned int nbyte; | |
475 | { | |
476 | char buffer[CMDBUFSIZE]; | |
477 | RETSIGTYPE (*pipe_handler) (); | |
478 | ||
479 | sprintf (buffer, "W%d\n", nbyte); | |
480 | if (command (fildes, buffer) == -1) | |
481 | return -1; | |
482 | ||
483 | pipe_handler = signal (SIGPIPE, SIG_IGN); | |
484 | if (write (WRITE (fildes), buf, nbyte) == nbyte) | |
485 | { | |
486 | signal (SIGPIPE, pipe_handler); | |
487 | return status (fildes); | |
488 | } | |
489 | ||
490 | /* Write error. */ | |
491 | signal (SIGPIPE, pipe_handler); | |
492 | _rmt_shutdown (fildes); | |
493 | errno = EIO; | |
494 | return -1; | |
495 | } | |
496 | ||
497 | /* Perform an imitation lseek operation on remote tape connection FILDES. | |
498 | Return the new file offset if successful, -1 if on error. */ | |
499 | ||
500 | long | |
501 | __rmt_lseek (fildes, offset, whence) | |
502 | int fildes; | |
503 | long offset; | |
504 | int whence; | |
505 | { | |
506 | char buffer[CMDBUFSIZE]; | |
507 | ||
508 | sprintf (buffer, "L%ld\n%d\n", offset, whence); | |
509 | if (command (fildes, buffer) == -1) | |
510 | return -1; | |
511 | ||
512 | return status (fildes); | |
513 | } | |
514 | ||
515 | /* Perform a raw tape operation on remote tape connection FILDES. | |
516 | Return the results of the ioctl, or -1 on error. */ | |
517 | ||
518 | #ifdef MTIOCTOP | |
519 | int | |
520 | __rmt_ioctl (fildes, op, arg) | |
521 | int fildes, op; | |
522 | char *arg; | |
523 | { | |
524 | char c; | |
525 | int rc, cnt; | |
526 | char buffer[CMDBUFSIZE]; | |
527 | ||
528 | switch (op) | |
529 | { | |
530 | default: | |
531 | errno = EINVAL; | |
532 | return -1; | |
533 | ||
534 | case MTIOCTOP: | |
535 | /* MTIOCTOP is the easy one. Nothing is transfered in binary. */ | |
536 | sprintf (buffer, "I%d\n%d\n", ((struct mtop *) arg)->mt_op, | |
537 | ((struct mtop *) arg)->mt_count); | |
538 | if (command (fildes, buffer) == -1) | |
539 | return -1; | |
540 | return status (fildes); /* Return the count. */ | |
541 | ||
542 | case MTIOCGET: | |
543 | /* Grab the status and read it directly into the structure. | |
544 | This assumes that the status buffer is not padded | |
545 | and that 2 shorts fit in a long without any word | |
546 | alignment problems; i.e., the whole struct is contiguous. | |
547 | NOTE - this is probably NOT a good assumption. */ | |
548 | ||
549 | if (command (fildes, "S") == -1 || (rc = status (fildes)) == -1) | |
550 | return -1; | |
551 | ||
552 | for (; rc > 0; rc -= cnt, arg += cnt) | |
553 | { | |
554 | cnt = read (READ (fildes), arg, rc); | |
555 | if (cnt <= 0) | |
556 | { | |
557 | _rmt_shutdown (fildes); | |
558 | errno = EIO; | |
559 | return -1; | |
560 | } | |
561 | } | |
562 | ||
563 | /* Check for byte position. mt_type is a small integer field | |
564 | (normally) so we will check its magnitude. If it is larger than | |
565 | 256, we will assume that the bytes are swapped and go through | |
566 | and reverse all the bytes. */ | |
567 | ||
568 | if (((struct mtget *) arg)->mt_type < 256) | |
569 | return 0; | |
570 | ||
571 | for (cnt = 0; cnt < rc; cnt += 2) | |
572 | { | |
573 | c = arg[cnt]; | |
574 | arg[cnt] = arg[cnt + 1]; | |
575 | arg[cnt + 1] = c; | |
576 | } | |
577 | ||
578 | return 0; | |
579 | } | |
580 | } | |
581 | ||
582 | #endif |