summaryrefslogtreecommitdiffstats
path: root/contrib/cpio/rtapelib.c
blob: 6550a6cd5bd417c20cdb245d6d21e25d8625dbb7 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
/* Functions for communicating with a remote tape drive.
   Copyright (C) 1988, 1992 Free Software Foundation, Inc.

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2, or (at your option)
   any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

/* The man page rmt(8) for /etc/rmt documents the remote mag tape
   protocol which rdump and rrestore use.  Unfortunately, the man
   page is *WRONG*.  The author of the routines I'm including originally
   wrote his code just based on the man page, and it didn't work, so he
   went to the rdump source to figure out why.  The only thing he had to
   change was to check for the 'F' return code in addition to the 'E',
   and to separate the various arguments with \n instead of a space.  I
   personally don't think that this is much of a problem, but I wanted to
   point it out. -- Arnold Robbins

   Originally written by Jeff Lee, modified some by Arnold Robbins.
   Redone as a library that can replace open, read, write, etc., by
   Fred Fish, with some additional work by Arnold Robbins.
   Modified to make all rmtXXX calls into macros for speed by Jay Fenlason.
   Use -DHAVE_NETDB_H for rexec code, courtesy of Dan Kegel, srs!dan.  */

#include <stdio.h>
#include <sys/types.h>
#include <signal.h>

#ifdef HAVE_SYS_MTIO_H
#include <sys/ioctl.h>
#include <sys/mtio.h>
#endif

#ifdef HAVE_NETDB_H
#include <netdb.h>
#endif

#include <errno.h>
#include <setjmp.h>
#include <sys/stat.h>

#ifndef errno
extern int errno;
#endif

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif
#ifdef STDC_HEADERS
#include <string.h>
#include <stdlib.h>
#endif

/* Maximum size of a fully qualified host name.  */
#define MAXHOSTLEN 257

/* Size of buffers for reading and writing commands to rmt.
   (An arbitrary limit.)  */
#define CMDBUFSIZE 64

#ifndef RETSIGTYPE
#define RETSIGTYPE void
#endif

/* Maximum number of simultaneous remote tape connections.
   (Another arbitrary limit.)  */
#define MAXUNIT	4

/* Return the parent's read side of remote tape connection FILDES.  */
#define READ(fildes) (from_rmt[fildes][0])

/* Return the parent's write side of remote tape connection FILDES.  */
#define WRITE(fildes) (to_rmt[fildes][1])

/* The pipes for receiving data from remote tape drives.  */
static int from_rmt[MAXUNIT][2] =
{-1, -1, -1, -1, -1, -1, -1, -1};

/* The pipes for sending data to remote tape drives.  */
static int to_rmt[MAXUNIT][2] =
{-1, -1, -1, -1, -1, -1, -1, -1};

/* Temporary variable used by macros in rmt.h.  */
char *__rmt_path;

/* Close remote tape connection FILDES.  */

static void
_rmt_shutdown (fildes)
     int fildes;
{
  close (READ (fildes));
  close (WRITE (fildes));
  READ (fildes) = -1;
  WRITE (fildes) = -1;
}

/* Attempt to perform the remote tape command specified in BUF
   on remote tape connection FILDES.
   Return 0 if successful, -1 on error.  */

static int
command (fildes, buf)
     int fildes;
     char *buf;
{
  register int buflen;
  RETSIGTYPE (*pipe_handler) ();

  /* Save the current pipe handler and try to make the request.  */

  pipe_handler = signal (SIGPIPE, SIG_IGN);
  buflen = strlen (buf);
  if (write (WRITE (fildes), buf, buflen) == buflen)
    {
      signal (SIGPIPE, pipe_handler);
      return 0;
    }

  /* Something went wrong.  Close down and go home.  */

  signal (SIGPIPE, pipe_handler);
  _rmt_shutdown (fildes);
  errno = EIO;
  return -1;
}

/* Read and return the status from remote tape connection FILDES.
   If an error occurred, return -1 and set errno.  */

static int
status (fildes)
     int fildes;
{
  int i;
  char c, *cp;
  char buffer[CMDBUFSIZE];

  /* Read the reply command line.  */

  for (i = 0, cp = buffer; i < CMDBUFSIZE; i++, cp++)
    {
      if (read (READ (fildes), cp, 1) != 1)
	{
	  _rmt_shutdown (fildes);
	  errno = EIO;
	  return -1;
	}
      if (*cp == '\n')
	{
	  *cp = '\0';
	  break;
	}
    }

  if (i == CMDBUFSIZE)
    {
      _rmt_shutdown (fildes);
      errno = EIO;
      return -1;
    }

  /* Check the return status.  */

  for (cp = buffer; *cp; cp++)
    if (*cp != ' ')
      break;

  if (*cp == 'E' || *cp == 'F')
    {
      errno = atoi (cp + 1);
      /* Skip the error message line.  */
      while (read (READ (fildes), &c, 1) == 1)
	if (c == '\n')
	  break;

      if (*cp == 'F')
	_rmt_shutdown (fildes);

      return -1;
    }

  /* Check for mis-synced pipes. */

  if (*cp != 'A')
    {
      _rmt_shutdown (fildes);
      errno = EIO;
      return -1;
    }

  /* Got an `A' (success) response.  */
  return atoi (cp + 1);
}

#ifdef HAVE_NETDB_H
/* Execute /etc/rmt as user USER on remote system HOST using rexec.
   Return a file descriptor of a bidirectional socket for stdin and stdout.
   If USER is NULL, or an empty string, use the current username.

   By default, this code is not used, since it requires that
   the user have a .netrc file in his/her home directory, or that the
   application designer be willing to have rexec prompt for login and
   password info.  This may be unacceptable, and .rhosts files for use
   with rsh are much more common on BSD systems.  */

static int
_rmt_rexec (host, user)
     char *host;
     char *user;
{
  struct servent *rexecserv;
  int save_stdin = dup (fileno (stdin));
  int save_stdout = dup (fileno (stdout));
  int tape_fd;			/* Return value. */

  /* When using cpio -o < filename, stdin is no longer the tty.
     But the rexec subroutine reads the login and the passwd on stdin,
     to allow remote execution of the command.
     So, reopen stdin and stdout on /dev/tty before the rexec and
     give them back their original value after.  */
  if (freopen ("/dev/tty", "r", stdin) == NULL)
    freopen ("/dev/null", "r", stdin);
  if (freopen ("/dev/tty", "w", stdout) == NULL)
    freopen ("/dev/null", "w", stdout);

  rexecserv = getservbyname ("exec", "tcp");
  if (NULL == rexecserv)
    {
      fprintf (stderr, "exec/tcp: service not available");
      exit (1);
    }
  if (user != NULL && *user == '\0')
    user = NULL;
  tape_fd = rexec (&host, rexecserv->s_port, user, NULL,
		   "/etc/rmt", (int *) NULL);
  fclose (stdin);
  fdopen (save_stdin, "r");
  fclose (stdout);
  fdopen (save_stdout, "w");

  return tape_fd;
}

#endif /* HAVE_NETDB_H */

/* Open a magtape device on the system specified in PATH, as the given user.
   PATH has the form `[user@]system:/dev/????'.
   If COMPAT is defined, it can also have the form `system[.user]:/dev/????'.

   OFLAG is O_RDONLY, O_WRONLY, etc.
   MODE is ignored; 0666 is always used.

   If successful, return the remote tape pipe number plus BIAS.
   On error, return -1.  */

int
__rmt_open (path, oflag, mode, bias)
     char *path;
     int oflag;
     int mode;
     int bias;
{
  int i, rc;
  char buffer[CMDBUFSIZE];	/* Command buffer.  */
  char system[MAXHOSTLEN];	/* The remote host name.  */
  char device[CMDBUFSIZE];	/* The remote device name.  */
  char login[CMDBUFSIZE];	/* The remote user name.  */
  char *sys, *dev, *user;	/* For copying into the above buffers.  */

  sys = system;
  dev = device;
  user = login;

  /* Find an unused pair of file descriptors.  */

  for (i = 0; i < MAXUNIT; i++)
    if (READ (i) == -1 && WRITE (i) == -1)
      break;

  if (i == MAXUNIT)
    {
      errno = EMFILE;
      return -1;
    }

  /* Pull apart the system and device, and optional user.
     Don't munge the original string.  */

  while (*path != '@'
#ifdef COMPAT
	 && *path != '.'
#endif
	 && *path != ':')
    {
      *sys++ = *path++;
    }
  *sys = '\0';
  path++;

  if (*(path - 1) == '@')
    {
      /* Saw user part of user@host.  Start over. */
      strcpy (user, system);
      sys = system;
      while (*path != ':')
	{
	  *sys++ = *path++;
	}
      *sys = '\0';
      path++;
    }
#ifdef COMPAT
  else if (*(path - 1) == '.')
    {
      while (*path != ':')
	{
	  *user++ = *path++;
	}
      *user = '\0';
      path++;
    }
#endif
  else
    *user = '\0';

  while (*path)
    {
      *dev++ = *path++;
    }
  *dev = '\0';

#ifdef HAVE_NETDB_H
  /* Execute the remote command using rexec.  */
  READ (i) = WRITE (i) = _rmt_rexec (system, login);
  if (READ (i) < 0)
    return -1;
#else /* !HAVE_NETDB_H */
  /* Set up the pipes for the `rsh' command, and fork.  */

  if (pipe (to_rmt[i]) == -1 || pipe (from_rmt[i]) == -1)
    return -1;

  rc = fork ();
  if (rc == -1)
    return -1;

  if (rc == 0)
    {
      /* Child.  */
      close (0);
      dup (to_rmt[i][0]);
      close (to_rmt[i][0]);
      close (to_rmt[i][1]);

      close (1);
      dup (from_rmt[i][1]);
      close (from_rmt[i][0]);
      close (from_rmt[i][1]);

      setuid (getuid ());
      setgid (getgid ());

      if (*login)
	{
	  execl ("/usr/bin/rsh", "rsh", "-l", login, system,
		 "/etc/rmt", (char *) 0);
	}
      else
	{
	  execl ("/usr/bin/rsh", "rsh", system,
		 "/etc/rmt", (char *) 0);
	}

      /* Bad problems if we get here.  */

      perror ("cannot execute remote shell");
      _exit (1);
    }

  /* Parent.  */
  close (to_rmt[i][0]);
  close (from_rmt[i][1]);
#endif /* !HAVE_NETDB_H */

  /* Attempt to open the tape device.  */

  sprintf (buffer, "O%s\n%d\n", device, oflag);
  if (command (i, buffer) == -1 || status (i) == -1)
    return -1;

  return i + bias;
}

/* Close remote tape connection FILDES and shut down.
   Return 0 if successful, -1 on error.  */

int
__rmt_close (fildes)
     int fildes;
{
  int rc;

  if (command (fildes, "C\n") == -1)
    return -1;

  rc = status (fildes);
  _rmt_shutdown (fildes);
  return rc;
}

/* Read up to NBYTE bytes into BUF from remote tape connection FILDES.
   Return the number of bytes read on success, -1 on error.  */

int
__rmt_read (fildes, buf, nbyte)
     int fildes;
     char *buf;
     unsigned int nbyte;
{
  int rc, i;
  char buffer[CMDBUFSIZE];

  sprintf (buffer, "R%d\n", nbyte);
  if (command (fildes, buffer) == -1 || (rc = status (fildes)) == -1)
    return -1;

  for (i = 0; i < rc; i += nbyte, buf += nbyte)
    {
      nbyte = read (READ (fildes), buf, rc - i);
      if (nbyte <= 0)
	{
	  _rmt_shutdown (fildes);
	  errno = EIO;
	  return -1;
	}
    }

  return rc;
}

/* Write NBYTE bytes from BUF to remote tape connection FILDES.
   Return the number of bytes written on success, -1 on error.  */

int
__rmt_write (fildes, buf, nbyte)
     int fildes;
     char *buf;
     unsigned int nbyte;
{
  char buffer[CMDBUFSIZE];
  RETSIGTYPE (*pipe_handler) ();

  sprintf (buffer, "W%d\n", nbyte);
  if (command (fildes, buffer) == -1)
    return -1;

  pipe_handler = signal (SIGPIPE, SIG_IGN);
  if (write (WRITE (fildes), buf, nbyte) == nbyte)
    {
      signal (SIGPIPE, pipe_handler);
      return status (fildes);
    }

  /* Write error.  */
  signal (SIGPIPE, pipe_handler);
  _rmt_shutdown (fildes);
  errno = EIO;
  return -1;
}

/* Perform an imitation lseek operation on remote tape connection FILDES.
   Return the new file offset if successful, -1 if on error.  */

long
__rmt_lseek (fildes, offset, whence)
     int fildes;
     long offset;
     int whence;
{
  char buffer[CMDBUFSIZE];

  sprintf (buffer, "L%ld\n%d\n", offset, whence);
  if (command (fildes, buffer) == -1)
    return -1;

  return status (fildes);
}

/* Perform a raw tape operation on remote tape connection FILDES.
   Return the results of the ioctl, or -1 on error.  */

#ifdef MTIOCTOP
int
__rmt_ioctl (fildes, op, arg)
     int fildes, op;
     char *arg;
{
  char c;
  int rc, cnt;
  char buffer[CMDBUFSIZE];

  switch (op)
    {
    default:
      errno = EINVAL;
      return -1;

    case MTIOCTOP:
      /* MTIOCTOP is the easy one.  Nothing is transfered in binary.  */
      sprintf (buffer, "I%d\n%d\n", ((struct mtop *) arg)->mt_op,
	       ((struct mtop *) arg)->mt_count);
      if (command (fildes, buffer) == -1)
	return -1;
      return status (fildes);	/* Return the count.  */

    case MTIOCGET:
      /* Grab the status and read it directly into the structure.
	 This assumes that the status buffer is not padded
	 and that 2 shorts fit in a long without any word
	 alignment problems; i.e., the whole struct is contiguous.
	 NOTE - this is probably NOT a good assumption.  */

      if (command (fildes, "S") == -1 || (rc = status (fildes)) == -1)
	return -1;

      for (; rc > 0; rc -= cnt, arg += cnt)
	{
	  cnt = read (READ (fildes), arg, rc);
	  if (cnt <= 0)
	    {
	      _rmt_shutdown (fildes);
	      errno = EIO;
	      return -1;
	    }
	}

      /* Check for byte position.  mt_type is a small integer field
	 (normally) so we will check its magnitude.  If it is larger than
	 256, we will assume that the bytes are swapped and go through
	 and reverse all the bytes.  */

      if (((struct mtget *) arg)->mt_type < 256)
	return 0;

      for (cnt = 0; cnt < rc; cnt += 2)
	{
	  c = arg[cnt];
	  arg[cnt] = arg[cnt + 1];
	  arg[cnt + 1] = c;
	}

      return 0;
    }
}

#endif
OpenPOWER on IntegriCloud