source: trunk/minix/commands/pax/ar_io.c@ 15

Last change on this file since 15 was 9, checked in by Mattia Monga, 14 years ago

Minix 3.1.2a
File size: 32.0 KB
RevLine 
[9]1/*-
2 * Copyright (c) 1992 Keith Muller.
3 * Copyright (c) 1992, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Keith Muller of the University of California, San Diego.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 4. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#ifndef lint
35#if 0
36static char sccsid[] = "@(#)ar_io.c 8.2 (Berkeley) 4/18/94";
37#endif
38#endif /* not lint */
39
40#include <sys/types.h>
41#include <sys/ioctl.h>
42#include <sys/mtio.h>
43#include <sys/stat.h>
44#include <sys/wait.h>
45#include <errno.h>
46#include <fcntl.h>
47#include <signal.h>
48#include <stdint.h>
49#include <stdio.h>
50#include <string.h>
51#include <stdlib.h>
52#include <unistd.h>
53#include "pax.h"
54#include "options.h"
55#include "extern.h"
56
57/*
58 * Routines which deal directly with the archive I/O device/file.
59 */
60
61#define DMOD 0666 /* default mode of created archives */
62#define EXT_MODE O_RDONLY /* open mode for list/extract */
63#define AR_MODE (O_WRONLY | O_CREAT | O_TRUNC) /* mode for archive */
64#define APP_MODE O_RDWR /* mode for append */
65
66static char none[] = "<NONE>"; /* pseudo name for no file */
67static char stdo[] = "<STDOUT>"; /* pseudo name for stdout */
68static char stdn[] = "<STDIN>"; /* pseudo name for stdin */
69static int arfd = -1; /* archive file descriptor */
70static int artyp = ISREG; /* archive type: file/FIFO/tape */
71static int arvol = 1; /* archive volume number */
72static int lstrval = -1; /* return value from last i/o */
73static int io_ok; /* i/o worked on volume after resync */
74static int did_io; /* did i/o ever occur on volume? */
75static int done; /* set via tty termination */
76static struct stat arsb; /* stat of archive device at open */
77static int invld_rec; /* tape has out of spec record size */
78static int wr_trail = 1; /* trailer was rewritten in append */
79static int can_unlnk = 0; /* do we unlink null archives? */
80const char *arcname; /* printable name of archive */
81const char *gzip_program; /* name of gzip program */
82static pid_t zpid = -1; /* pid of child process */
83
84static int get_phys(void);
85extern sigset_t s_mask;
86static void ar_start_gzip(int, const char *, int);
87
88/*
89 * ar_open()
90 * Opens the next archive volume. Determines the type of the device and
91 * sets up block sizes as required by the archive device and the format.
92 * Note: we may be called with name == NULL on the first open only.
93 * Return:
94 * -1 on failure, 0 otherwise
95 */
96
97int
98ar_open(const char *name)
99{
100 struct mtget mb;
101
102 if (arfd != -1)
103 (void)close(arfd);
104 arfd = -1;
105 can_unlnk = did_io = io_ok = invld_rec = 0;
106 artyp = ISREG;
107 flcnt = 0;
108
109 /*
110 * open based on overall operation mode
111 */
112 switch (act) {
113 case LIST:
114 case EXTRACT:
115 if (name == NULL) {
116 arfd = STDIN_FILENO;
117 arcname = stdn;
118 } else if ((arfd = open(name, EXT_MODE, DMOD)) < 0)
119 syswarn(0, errno, "Failed open to read on %s", name);
120 if (arfd != -1 && gzip_program != NULL)
121 ar_start_gzip(arfd, gzip_program, 0);
122 break;
123 case ARCHIVE:
124 if (name == NULL) {
125 arfd = STDOUT_FILENO;
126 arcname = stdo;
127 } else if ((arfd = open(name, AR_MODE, DMOD)) < 0)
128 syswarn(0, errno, "Failed open to write on %s", name);
129 else
130 can_unlnk = 1;
131 if (arfd != -1 && gzip_program != NULL)
132 ar_start_gzip(arfd, gzip_program, 1);
133 break;
134 case APPND:
135 if (name == NULL) {
136 arfd = STDOUT_FILENO;
137 arcname = stdo;
138 } else if ((arfd = open(name, APP_MODE, DMOD)) < 0)
139 syswarn(0, errno, "Failed open to read/write on %s",
140 name);
141 break;
142 case COPY:
143 /*
144 * arfd not used in COPY mode
145 */
146 arcname = none;
147 lstrval = 1;
148 return(0);
149 }
150 if (arfd < 0)
151 return(-1);
152
153 if (chdname != NULL)
154 if (chdir(chdname) != 0) {
155 syswarn(1, errno, "Failed chdir to %s", chdname);
156 return(-1);
157 }
158 /*
159 * set up is based on device type
160 */
161 if (fstat(arfd, &arsb) < 0) {
162 syswarn(0, errno, "Failed stat on %s", arcname);
163 (void)close(arfd);
164 arfd = -1;
165 can_unlnk = 0;
166 return(-1);
167 }
168 if (S_ISDIR(arsb.st_mode)) {
169 paxwarn(0, "Cannot write an archive on top of a directory %s",
170 arcname);
171 (void)close(arfd);
172 arfd = -1;
173 can_unlnk = 0;
174 return(-1);
175 }
176
177 if (S_ISCHR(arsb.st_mode))
178 artyp = ioctl(arfd, MTIOCGET, &mb) ? ISCHR : ISTAPE;
179 else if (S_ISBLK(arsb.st_mode))
180 artyp = ISBLK;
181 else if ((lseek(arfd, (off_t)0L, SEEK_CUR) == -1) && (errno == ESPIPE))
182 artyp = ISPIPE;
183 else
184 artyp = ISREG;
185
186 /*
187 * make sure we beyond any doubt that we only can unlink regular files
188 * we created
189 */
190 if (artyp != ISREG)
191 can_unlnk = 0;
192 /*
193 * if we are writing, we are done
194 */
195 if (act == ARCHIVE) {
196 blksz = rdblksz = wrblksz;
197 lstrval = 1;
198 return(0);
199 }
200
201 /*
202 * set default blksz on read. APPNDs writes rdblksz on the last volume
203 * On all new archive volumes, we shift to wrblksz (if the user
204 * specified one, otherwize we will continue to use rdblksz). We
205 * must to set blocksize based on what kind of device the archive is
206 * stored.
207 */
208 switch(artyp) {
209 case ISTAPE:
210 /*
211 * Tape drives come in at least two flavors. Those that support
212 * variable sized records and those that have fixed sized
213 * records. They must be treated differently. For tape drives
214 * that support variable sized records, we must make large
215 * reads to make sure we get the entire record, otherwise we
216 * will just get the first part of the record (up to size we
217 * asked). Tapes with fixed sized records may or may not return
218 * multiple records in a single read. We really do not care
219 * what the physical record size is UNLESS we are going to
220 * append. (We will need the physical block size to rewrite
221 * the trailer). Only when we are appending do we go to the
222 * effort to figure out the true PHYSICAL record size.
223 */
224 blksz = rdblksz = MAXBLK;
225 break;
226 case ISPIPE:
227 case ISBLK:
228 case ISCHR:
229 /*
230 * Blocksize is not a major issue with these devices (but must
231 * be kept a multiple of 512). If the user specified a write
232 * block size, we use that to read. Under append, we must
233 * always keep blksz == rdblksz. Otherwise we go ahead and use
234 * the device optimal blocksize as (and if) returned by stat
235 * and if it is within pax specs.
236 */
237 if ((act == APPND) && wrblksz) {
238 blksz = rdblksz = wrblksz;
239 break;
240 }
241
242#if 0 /* Not on minix */
243 if ((arsb.st_blksize > 0) && (arsb.st_blksize < MAXBLK) &&
244 ((arsb.st_blksize % BLKMULT) == 0))
245 rdblksz = arsb.st_blksize;
246 else
247#endif
248 rdblksz = DEVBLK;
249 /*
250 * For performance go for large reads when we can without harm
251 */
252 if ((act == APPND) || (artyp == ISCHR))
253 blksz = rdblksz;
254 else
255 blksz = MAXBLK;
256 break;
257 case ISREG:
258 /*
259 * if the user specified wrblksz works, use it. Under appends
260 * we must always keep blksz == rdblksz
261 */
262 if ((act == APPND) && wrblksz && ((arsb.st_size%wrblksz)==0)){
263 blksz = rdblksz = wrblksz;
264 break;
265 }
266 /*
267 * See if we can find the blocking factor from the file size
268 */
269 for (rdblksz = MAXBLK; rdblksz > 0; rdblksz -= BLKMULT)
270 if ((arsb.st_size % rdblksz) == 0)
271 break;
272 /*
273 * When we cannot find a match, we may have a flawed archive.
274 */
275 if (rdblksz <= 0)
276 rdblksz = FILEBLK;
277 /*
278 * for performance go for large reads when we can
279 */
280 if (act == APPND)
281 blksz = rdblksz;
282 else
283 blksz = MAXBLK;
284 break;
285 default:
286 /*
287 * should never happen, worse case, slow...
288 */
289 blksz = rdblksz = BLKMULT;
290 break;
291 }
292 lstrval = 1;
293 return(0);
294}
295
296/*
297 * ar_close()
298 * closes archive device, increments volume number, and prints i/o summary
299 */
300void
301ar_close(void)
302{
303 int status;
304
305 if (arfd < 0) {
306 did_io = io_ok = flcnt = 0;
307 return;
308 }
309
310 /*
311 * Close archive file. This may take a LONG while on tapes (we may be
312 * forced to wait for the rewind to complete) so tell the user what is
313 * going on (this avoids the user hitting control-c thinking pax is
314 * broken).
315 */
316 if (vflag && (artyp == ISTAPE)) {
317 if (vfpart)
318 (void)putc('\n', listf);
319 (void)fprintf(listf,
320 "%s: Waiting for tape drive close to complete...",
321 argv0);
322 (void)fflush(listf);
323 }
324
325 /*
326 * if nothing was written to the archive (and we created it), we remove
327 * it
328 */
329 if (can_unlnk && (fstat(arfd, &arsb) == 0) && (S_ISREG(arsb.st_mode)) &&
330 (arsb.st_size == 0)) {
331 (void)unlink(arcname);
332 can_unlnk = 0;
333 }
334
335 /*
336 * for a quick extract/list, pax frequently exits before the child
337 * process is done
338 */
339 if ((act == LIST || act == EXTRACT) && nflag && zpid > 0)
340 kill(zpid, SIGINT);
341
342 (void)close(arfd);
343
344 /* Do not exit before child to ensure data integrity */
345 if (zpid > 0)
346 waitpid(zpid, &status, 0);
347
348 if (vflag && (artyp == ISTAPE)) {
349 (void)fputs("done.\n", listf);
350 vfpart = 0;
351 (void)fflush(listf);
352 }
353 arfd = -1;
354
355 if (!io_ok && !did_io) {
356 flcnt = 0;
357 return;
358 }
359 did_io = io_ok = 0;
360
361 /*
362 * The volume number is only increased when the last device has data
363 * and we have already determined the archive format.
364 */
365 if (frmt != NULL)
366 ++arvol;
367
368 if (!vflag) {
369 flcnt = 0;
370 return;
371 }
372
373 /*
374 * Print out a summary of I/O for this archive volume.
375 */
376 if (vfpart) {
377 (void)putc('\n', listf);
378 vfpart = 0;
379 }
380
381 /*
382 * If we have not determined the format yet, we just say how many bytes
383 * we have skipped over looking for a header to id. there is no way we
384 * could have written anything yet.
385 */
386 if (frmt == NULL) {
387# ifdef NET2_STAT
388 (void)fprintf(listf, "%s: unknown format, %lu bytes skipped.\n",
389 argv0, rdcnt);
390# else
391 (void)fprintf(listf, "%s: unknown format, %ju bytes skipped.\n",
392 argv0, (uintmax_t)rdcnt);
393# endif
394 (void)fflush(listf);
395 flcnt = 0;
396 return;
397 }
398
399 if (strcmp(NM_CPIO, argv0) == 0)
400 (void)fprintf(listf, "%llu blocks\n",
401 (unsigned long)((rdcnt ? rdcnt : wrcnt) / 5120));
402 else if (strcmp(NM_TAR, argv0) != 0)
403 (void)fprintf(listf,
404# ifdef NET2_STAT
405 "%s: %s vol %d, %lu files, %lu bytes read, %lu bytes written.\n",
406 argv0, frmt->name, arvol-1, flcnt, rdcnt, wrcnt);
407# else
408 "%s: %s vol %d, %ju files, %ju bytes read, %ju bytes written.\n",
409 argv0, frmt->name, arvol-1, (uintmax_t)flcnt,
410 (uintmax_t)rdcnt, (uintmax_t)wrcnt);
411# endif
412 (void)fflush(listf);
413 flcnt = 0;
414}
415
416/*
417 * ar_drain()
418 * drain any archive format independent padding from an archive read
419 * from a socket or a pipe. This is to prevent the process on the
420 * other side of the pipe from getting a SIGPIPE (pax will stop
421 * reading an archive once a format dependent trailer is detected).
422 */
423void
424ar_drain(void)
425{
426 int res;
427 char drbuf[MAXBLK];
428
429 /*
430 * we only drain from a pipe/socket. Other devices can be closed
431 * without reading up to end of file. We sure hope that pipe is closed
432 * on the other side so we will get an EOF.
433 */
434 if ((artyp != ISPIPE) || (lstrval <= 0))
435 return;
436
437 /*
438 * keep reading until pipe is drained
439 */
440 while ((res = read(arfd, drbuf, sizeof(drbuf))) > 0)
441 ;
442 lstrval = res;
443}
444
445/*
446 * ar_set_wr()
447 * Set up device right before switching from read to write in an append.
448 * device dependent code (if required) to do this should be added here.
449 * For all archive devices we are already positioned at the place we want
450 * to start writing when this routine is called.
451 * Return:
452 * 0 if all ready to write, -1 otherwise
453 */
454
455int
456ar_set_wr(void)
457{
458 off_t cpos;
459
460 /*
461 * we must make sure the trailer is rewritten on append, ar_next()
462 * will stop us if the archive containing the trailer was not written
463 */
464 wr_trail = 0;
465
466 /*
467 * Add any device dependent code as required here
468 */
469 if (artyp != ISREG)
470 return(0);
471 /*
472 * Ok we have an archive in a regular file. If we were rewriting a
473 * file, we must get rid of all the stuff after the current offset
474 * (it was not written by pax).
475 */
476 if (((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) ||
477 (ftruncate(arfd, cpos) < 0)) {
478 syswarn(1, errno, "Unable to truncate archive file");
479 return(-1);
480 }
481 return(0);
482}
483
484/*
485 * ar_app_ok()
486 * check if the last volume in the archive allows appends. We cannot check
487 * this until we are ready to write since there is no spec that says all
488 * volumes in a single archive have to be of the same type...
489 * Return:
490 * 0 if we can append, -1 otherwise.
491 */
492
493int
494ar_app_ok(void)
495{
496 if (artyp == ISPIPE) {
497 paxwarn(1, "Cannot append to an archive obtained from a pipe.");
498 return(-1);
499 }
500
501 if (!invld_rec)
502 return(0);
503 paxwarn(1,"Cannot append, device record size %d does not support %s spec",
504 rdblksz, argv0);
505 return(-1);
506}
507
508/*
509 * ar_read()
510 * read up to a specified number of bytes from the archive into the
511 * supplied buffer. When dealing with tapes we may not always be able to
512 * read what we want.
513 * Return:
514 * Number of bytes in buffer. 0 for end of file, -1 for a read error.
515 */
516
517int
518ar_read(char *buf, int cnt)
519{
520 int res = 0;
521
522 /*
523 * if last i/o was in error, no more reads until reset or new volume
524 */
525 if (lstrval <= 0)
526 return(lstrval);
527
528 /*
529 * how we read must be based on device type
530 */
531 switch (artyp) {
532 case ISTAPE:
533 if ((res = read(arfd, buf, cnt)) > 0) {
534 /*
535 * CAUTION: tape systems may not always return the same
536 * sized records so we leave blksz == MAXBLK. The
537 * physical record size that a tape drive supports is
538 * very hard to determine in a uniform and portable
539 * manner.
540 */
541 io_ok = 1;
542 if (res != rdblksz) {
543 /*
544 * Record size changed. If this is happens on
545 * any record after the first, we probably have
546 * a tape drive which has a fixed record size
547 * we are getting multiple records in a single
548 * read). Watch out for record blocking that
549 * violates pax spec (must be a multiple of
550 * BLKMULT).
551 */
552 rdblksz = res;
553 if (rdblksz % BLKMULT)
554 invld_rec = 1;
555 }
556 return(res);
557 }
558 break;
559 case ISREG:
560 case ISBLK:
561 case ISCHR:
562 case ISPIPE:
563 default:
564 /*
565 * Files are so easy to deal with. These other things cannot
566 * be trusted at all. So when we are dealing with character
567 * devices and pipes we just take what they have ready for us
568 * and return. Trying to do anything else with them runs the
569 * risk of failure.
570 */
571 if ((res = read(arfd, buf, cnt)) > 0) {
572 io_ok = 1;
573 return(res);
574 }
575 break;
576 }
577
578 /*
579 * We are in trouble at this point, something is broken...
580 */
581 lstrval = res;
582 if (res < 0)
583 syswarn(1, errno, "Failed read on archive volume %d", arvol);
584 else
585 paxwarn(0, "End of archive volume %d reached", arvol);
586 return(res);
587}
588
589/*
590 * ar_write()
591 * Write a specified number of bytes in supplied buffer to the archive
592 * device so it appears as a single "block". Deals with errors and tries
593 * to recover when faced with short writes.
594 * Return:
595 * Number of bytes written. 0 indicates end of volume reached and with no
596 * flaws (as best that can be detected). A -1 indicates an unrecoverable
597 * error in the archive occured.
598 */
599
600int
601ar_write(char *buf, int bsz)
602{
603 int res;
604 off_t cpos;
605
606 /*
607 * do not allow pax to create a "bad" archive. Once a write fails on
608 * an archive volume prevent further writes to it.
609 */
610 if (lstrval <= 0)
611 return(lstrval);
612
613 if ((res = write(arfd, buf, bsz)) == bsz) {
614 wr_trail = 1;
615 io_ok = 1;
616 return(bsz);
617 }
618 /*
619 * write broke, see what we can do with it. We try to send any partial
620 * writes that may violate pax spec to the next archive volume.
621 */
622 if (res < 0)
623 lstrval = res;
624 else
625 lstrval = 0;
626
627 switch (artyp) {
628 case ISREG:
629 if ((res > 0) && (res % BLKMULT)) {
630 /*
631 * try to fix up partial writes which are not BLKMULT
632 * in size by forcing the runt record to next archive
633 * volume
634 */
635 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0)
636 break;
637 cpos -= (off_t)res;
638 if (ftruncate(arfd, cpos) < 0)
639 break;
640 res = lstrval = 0;
641 break;
642 }
643 if (res >= 0)
644 break;
645 /*
646 * if file is out of space, handle it like a return of 0
647 */
648 if ((errno == ENOSPC) || (errno == EFBIG)
649#ifdef EDQUOT
650 || (errno == EDQUOT)
651#endif
652 )
653 res = lstrval = 0;
654 break;
655 case ISTAPE:
656 case ISCHR:
657 case ISBLK:
658 if (res >= 0)
659 break;
660 if (errno == EACCES) {
661 paxwarn(0, "Write failed, archive is write protected.");
662 res = lstrval = 0;
663 return(0);
664 }
665 /*
666 * see if we reached the end of media, if so force a change to
667 * the next volume
668 */
669 if ((errno == ENOSPC) || (errno == EIO) || (errno == ENXIO))
670 res = lstrval = 0;
671 break;
672 case ISPIPE:
673 default:
674 /*
675 * we cannot fix errors to these devices
676 */
677 break;
678 }
679
680 /*
681 * Better tell the user the bad news...
682 * if this is a block aligned archive format, we may have a bad archive
683 * if the format wants the header to start at a BLKMULT boundary. While
684 * we can deal with the mis-aligned data, it violates spec and other
685 * archive readers will likely fail. if the format is not block
686 * aligned, the user may be lucky (and the archive is ok).
687 */
688 if (res >= 0) {
689 if (res > 0)
690 wr_trail = 1;
691 io_ok = 1;
692 }
693
694 /*
695 * If we were trying to rewrite the trailer and it didn't work, we
696 * must quit right away.
697 */
698 if (!wr_trail && (res <= 0)) {
699 paxwarn(1,"Unable to append, trailer re-write failed. Quitting.");
700 return(res);
701 }
702
703 if (res == 0)
704 paxwarn(0, "End of archive volume %d reached", arvol);
705 else if (res < 0)
706 syswarn(1, errno, "Failed write to archive volume: %d", arvol);
707 else if (!frmt->blkalgn || ((res % frmt->blkalgn) == 0))
708 paxwarn(0,"WARNING: partial archive write. Archive MAY BE FLAWED");
709 else
710 paxwarn(1,"WARNING: partial archive write. Archive IS FLAWED");
711 return(res);
712}
713
714/*
715 * ar_rdsync()
716 * Try to move past a bad spot on a flawed archive as needed to continue
717 * I/O. Clears error flags to allow I/O to continue.
718 * Return:
719 * 0 when ok to try i/o again, -1 otherwise.
720 */
721
722int
723ar_rdsync(void)
724{
725 long fsbz;
726 off_t cpos;
727 off_t mpos;
728 struct mtop mb;
729
730 /*
731 * Fail resync attempts at user request (done) or this is going to be
732 * an update/append to an existing archive. If last i/o hit media end,
733 * we need to go to the next volume not try a resync.
734 */
735 if ((done > 0) || (lstrval == 0))
736 return(-1);
737
738 if ((act == APPND) || (act == ARCHIVE)) {
739 paxwarn(1, "Cannot allow updates to an archive with flaws.");
740 return(-1);
741 }
742 if (io_ok)
743 did_io = 1;
744
745 switch(artyp) {
746 case ISTAPE:
747 /*
748 * if the last i/o was a successful data transfer, we assume
749 * the fault is just a bad record on the tape that we are now
750 * past. If we did not get any data since the last resync try
751 * to move the tape forward one PHYSICAL record past any
752 * damaged tape section. Some tape drives are stubborn and need
753 * to be pushed.
754 */
755 if (io_ok) {
756 io_ok = 0;
757 lstrval = 1;
758 break;
759 }
760 mb.mt_op = MTFSR;
761 mb.mt_count = 1;
762 if (ioctl(arfd, MTIOCTOP, &mb) < 0)
763 break;
764 lstrval = 1;
765 break;
766 case ISREG:
767 case ISCHR:
768 case ISBLK:
769 /*
770 * try to step over the bad part of the device.
771 */
772 io_ok = 0;
773#if 0
774 /* no blksize on minix */
775 if (((fsbz = arsb.st_blksize) <= 0) || (artyp != ISREG))
776#endif
777 fsbz = BLKMULT;
778 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0)
779 break;
780 mpos = fsbz - (cpos % (off_t)fsbz);
781 if (lseek(arfd, mpos, SEEK_CUR) < 0)
782 break;
783 lstrval = 1;
784 break;
785 case ISPIPE:
786 default:
787 /*
788 * cannot recover on these archive device types
789 */
790 io_ok = 0;
791 break;
792 }
793 if (lstrval <= 0) {
794 paxwarn(1, "Unable to recover from an archive read failure.");
795 return(-1);
796 }
797 paxwarn(0, "Attempting to recover from an archive read failure.");
798 return(0);
799}
800
801/*
802 * ar_fow()
803 * Move the I/O position within the archive foward the specified number of
804 * bytes as supported by the device. If we cannot move the requested
805 * number of bytes, return the actual number of bytes moved in skipped.
806 * Return:
807 * 0 if moved the requested distance, -1 on complete failure, 1 on
808 * partial move (the amount moved is in skipped)
809 */
810
811int
812ar_fow(off_t sksz, off_t *skipped)
813{
814 off_t cpos;
815 off_t mpos;
816
817 *skipped = 0;
818 if (sksz <= 0)
819 return(0);
820
821 /*
822 * we cannot move foward at EOF or error
823 */
824 if (lstrval <= 0)
825 return(lstrval);
826
827 /*
828 * Safer to read forward on devices where it is hard to find the end of
829 * the media without reading to it. With tapes we cannot be sure of the
830 * number of physical blocks to skip (we do not know physical block
831 * size at this point), so we must only read foward on tapes!
832 */
833 if (artyp != ISREG)
834 return(0);
835
836 /*
837 * figure out where we are in the archive
838 */
839 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) >= 0) {
840 /*
841 * we can be asked to move farther than there are bytes in this
842 * volume, if so, just go to file end and let normal buf_fill()
843 * deal with the end of file (it will go to next volume by
844 * itself)
845 */
846 if ((mpos = cpos + sksz) > arsb.st_size) {
847 *skipped = arsb.st_size - cpos;
848 mpos = arsb.st_size;
849 } else
850 *skipped = sksz;
851 if (lseek(arfd, mpos, SEEK_SET) >= 0)
852 return(0);
853 }
854 syswarn(1, errno, "Forward positioning operation on archive failed");
855 lstrval = -1;
856 return(-1);
857}
858
859/*
860 * ar_rev()
861 * move the i/o position within the archive backwards the specified byte
862 * count as supported by the device. With tapes drives we RESET rdblksz to
863 * the PHYSICAL blocksize.
864 * NOTE: We should only be called to move backwards so we can rewrite the
865 * last records (the trailer) of an archive (APPEND).
866 * Return:
867 * 0 if moved the requested distance, -1 on complete failure
868 */
869
870int
871ar_rev(off_t sksz)
872{
873 off_t cpos;
874 struct mtop mb;
875 int phyblk;
876
877 /*
878 * make sure we do not have try to reverse on a flawed archive
879 */
880 if (lstrval < 0)
881 return(lstrval);
882
883 switch(artyp) {
884 case ISPIPE:
885 if (sksz <= 0)
886 break;
887 /*
888 * cannot go backwards on these critters
889 */
890 paxwarn(1, "Reverse positioning on pipes is not supported.");
891 lstrval = -1;
892 return(-1);
893 case ISREG:
894 case ISBLK:
895 case ISCHR:
896 default:
897 if (sksz <= 0)
898 break;
899
900 /*
901 * For things other than files, backwards movement has a very
902 * high probability of failure as we really do not know the
903 * true attributes of the device we are talking to (the device
904 * may not even have the ability to lseek() in any direction).
905 * First we figure out where we are in the archive.
906 */
907 if ((cpos = lseek(arfd, (off_t)0L, SEEK_CUR)) < 0) {
908 syswarn(1, errno,
909 "Unable to obtain current archive byte offset");
910 lstrval = -1;
911 return(-1);
912 }
913
914 /*
915 * we may try to go backwards past the start when the archive
916 * is only a single record. If this hapens and we are on a
917 * multi volume archive, we need to go to the end of the
918 * previous volume and continue our movement backwards from
919 * there.
920 */
921 if ((cpos -= sksz) < (off_t)0L) {
922 if (arvol > 1) {
923 /*
924 * this should never happen
925 */
926 paxwarn(1,"Reverse position on previous volume.");
927 lstrval = -1;
928 return(-1);
929 }
930 cpos = (off_t)0L;
931 }
932 if (lseek(arfd, cpos, SEEK_SET) < 0) {
933 syswarn(1, errno, "Unable to seek archive backwards");
934 lstrval = -1;
935 return(-1);
936 }
937 break;
938 case ISTAPE:
939 /*
940 * Calculate and move the proper number of PHYSICAL tape
941 * blocks. If the sksz is not an even multiple of the physical
942 * tape size, we cannot do the move (this should never happen).
943 * (We also cannot handler trailers spread over two vols).
944 * get_phys() also makes sure we are in front of the filemark.
945 */
946 if ((phyblk = get_phys()) <= 0) {
947 lstrval = -1;
948 return(-1);
949 }
950
951 /*
952 * make sure future tape reads only go by physical tape block
953 * size (set rdblksz to the real size).
954 */
955 rdblksz = phyblk;
956
957 /*
958 * if no movement is required, just return (we must be after
959 * get_phys() so the physical blocksize is properly set)
960 */
961 if (sksz <= 0)
962 break;
963
964 /*
965 * ok we have to move. Make sure the tape drive can do it.
966 */
967 if (sksz % phyblk) {
968 paxwarn(1,
969 "Tape drive unable to backspace requested amount");
970 lstrval = -1;
971 return(-1);
972 }
973
974 /*
975 * move backwards the requested number of bytes
976 */
977 mb.mt_op = MTBSR;
978 mb.mt_count = sksz/phyblk;
979 if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
980 syswarn(1,errno, "Unable to backspace tape %d blocks.",
981 mb.mt_count);
982 lstrval = -1;
983 return(-1);
984 }
985 break;
986 }
987 lstrval = 1;
988 return(0);
989}
990
991/*
992 * get_phys()
993 * Determine the physical block size on a tape drive. We need the physical
994 * block size so we know how many bytes we skip over when we move with
995 * mtio commands. We also make sure we are BEFORE THE TAPE FILEMARK when
996 * return.
997 * This is one really SLOW routine...
998 * Return:
999 * physical block size if ok (ok > 0), -1 otherwise
1000 */
1001
1002static int
1003get_phys(void)
1004{
1005 int padsz = 0;
1006 int res;
1007 int phyblk;
1008 struct mtop mb;
1009 char scbuf[MAXBLK];
1010
1011 /*
1012 * move to the file mark, and then back up one record and read it.
1013 * this should tell us the physical record size the tape is using.
1014 */
1015 if (lstrval == 1) {
1016 /*
1017 * we know we are at file mark when we get back a 0 from
1018 * read()
1019 */
1020 while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0)
1021 padsz += res;
1022 if (res < 0) {
1023 syswarn(1, errno, "Unable to locate tape filemark.");
1024 return(-1);
1025 }
1026 }
1027
1028 /*
1029 * move backwards over the file mark so we are at the end of the
1030 * last record.
1031 */
1032 mb.mt_op = MTBSF;
1033 mb.mt_count = 1;
1034 if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
1035 syswarn(1, errno, "Unable to backspace over tape filemark.");
1036 return(-1);
1037 }
1038
1039 /*
1040 * move backwards so we are in front of the last record and read it to
1041 * get physical tape blocksize.
1042 */
1043 mb.mt_op = MTBSR;
1044 mb.mt_count = 1;
1045 if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
1046 syswarn(1, errno, "Unable to backspace over last tape block.");
1047 return(-1);
1048 }
1049 if ((phyblk = read(arfd, scbuf, sizeof(scbuf))) <= 0) {
1050 syswarn(1, errno, "Cannot determine archive tape blocksize.");
1051 return(-1);
1052 }
1053
1054 /*
1055 * read foward to the file mark, then back up in front of the filemark
1056 * (this is a bit paranoid, but should be safe to do).
1057 */
1058 while ((res = read(arfd, scbuf, sizeof(scbuf))) > 0)
1059 ;
1060 if (res < 0) {
1061 syswarn(1, errno, "Unable to locate tape filemark.");
1062 return(-1);
1063 }
1064 mb.mt_op = MTBSF;
1065 mb.mt_count = 1;
1066 if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
1067 syswarn(1, errno, "Unable to backspace over tape filemark.");
1068 return(-1);
1069 }
1070
1071 /*
1072 * set lstrval so we know that the filemark has not been seen
1073 */
1074 lstrval = 1;
1075
1076 /*
1077 * return if there was no padding
1078 */
1079 if (padsz == 0)
1080 return(phyblk);
1081
1082 /*
1083 * make sure we can move backwards over the padding. (this should
1084 * never fail).
1085 */
1086 if (padsz % phyblk) {
1087 paxwarn(1, "Tape drive unable to backspace requested amount");
1088 return(-1);
1089 }
1090
1091 /*
1092 * move backwards over the padding so the head is where it was when
1093 * we were first called (if required).
1094 */
1095 mb.mt_op = MTBSR;
1096 mb.mt_count = padsz/phyblk;
1097 if (ioctl(arfd, MTIOCTOP, &mb) < 0) {
1098 syswarn(1,errno,"Unable to backspace tape over %d pad blocks",
1099 mb.mt_count);
1100 return(-1);
1101 }
1102 return(phyblk);
1103}
1104
1105/*
1106 * ar_next()
1107 * prompts the user for the next volume in this archive. For some devices
1108 * we may allow the media to be changed. Otherwise a new archive is
1109 * prompted for. By pax spec, if there is no controlling tty or an eof is
1110 * read on tty input, we must quit pax.
1111 * Return:
1112 * 0 when ready to continue, -1 when all done
1113 */
1114
1115int
1116ar_next(void)
1117{
1118 char buf[PAXPATHLEN+2];
1119 static int freeit = 0;
1120 sigset_t o_mask;
1121
1122 /*
1123 * WE MUST CLOSE THE DEVICE. A lot of devices must see last close, (so
1124 * things like writing EOF etc will be done) (Watch out ar_close() can
1125 * also be called via a signal handler, so we must prevent a race.
1126 */
1127 if (sigprocmask(SIG_BLOCK, &s_mask, &o_mask) < 0)
1128 syswarn(0, errno, "Unable to set signal mask");
1129 ar_close();
1130 if (sigprocmask(SIG_SETMASK, &o_mask, NULL) < 0)
1131 syswarn(0, errno, "Unable to restore signal mask");
1132
1133 if (done || !wr_trail || strcmp(NM_TAR, argv0) == 0)
1134 return(-1);
1135
1136 tty_prnt("\nATTENTION! %s archive volume change required.\n", argv0);
1137
1138 /*
1139 * if i/o is on stdin or stdout, we cannot reopen it (we do not know
1140 * the name), the user will be forced to type it in.
1141 */
1142 if (strcmp(arcname, stdo) && strcmp(arcname, stdn) && (artyp != ISREG)
1143 && (artyp != ISPIPE)) {
1144 if (artyp == ISTAPE) {
1145 tty_prnt("%s ready for archive tape volume: %d\n",
1146 arcname, arvol);
1147 tty_prnt("Load the NEXT TAPE on the tape drive");
1148 } else {
1149 tty_prnt("%s ready for archive volume: %d\n",
1150 arcname, arvol);
1151 tty_prnt("Load the NEXT STORAGE MEDIA (if required)");
1152 }
1153
1154 if ((act == ARCHIVE) || (act == APPND))
1155 tty_prnt(" and make sure it is WRITE ENABLED.\n");
1156 else
1157 tty_prnt("\n");
1158
1159 for(;;) {
1160 tty_prnt("Type \"y\" to continue, \".\" to quit %s,",
1161 argv0);
1162 tty_prnt(" or \"s\" to switch to new device.\nIf you");
1163 tty_prnt(" cannot change storage media, type \"s\"\n");
1164 tty_prnt("Is the device ready and online? > ");
1165
1166 if ((tty_read(buf,sizeof(buf))<0) || !strcmp(buf,".")){
1167 done = 1;
1168 lstrval = -1;
1169 tty_prnt("Quitting %s!\n", argv0);
1170 vfpart = 0;
1171 return(-1);
1172 }
1173
1174 if ((buf[0] == '\0') || (buf[1] != '\0')) {
1175 tty_prnt("%s unknown command, try again\n",buf);
1176 continue;
1177 }
1178
1179 switch (buf[0]) {
1180 case 'y':
1181 case 'Y':
1182 /*
1183 * we are to continue with the same device
1184 */
1185 if (ar_open(arcname) >= 0)
1186 return(0);
1187 tty_prnt("Cannot re-open %s, try again\n",
1188 arcname);
1189 continue;
1190 case 's':
1191 case 'S':
1192 /*
1193 * user wants to open a different device
1194 */
1195 tty_prnt("Switching to a different archive\n");
1196 break;
1197 default:
1198 tty_prnt("%s unknown command, try again\n",buf);
1199 continue;
1200 }
1201 break;
1202 }
1203 } else
1204 tty_prnt("Ready for archive volume: %d\n", arvol);
1205
1206 /*
1207 * have to go to a different archive
1208 */
1209 for (;;) {
1210 tty_prnt("Input archive name or \".\" to quit %s.\n", argv0);
1211 tty_prnt("Archive name > ");
1212
1213 if ((tty_read(buf, sizeof(buf)) < 0) || !strcmp(buf, ".")) {
1214 done = 1;
1215 lstrval = -1;
1216 tty_prnt("Quitting %s!\n", argv0);
1217 vfpart = 0;
1218 return(-1);
1219 }
1220 if (buf[0] == '\0') {
1221 tty_prnt("Empty file name, try again\n");
1222 continue;
1223 }
1224 if (!strcmp(buf, "..")) {
1225 tty_prnt("Illegal file name: .. try again\n");
1226 continue;
1227 }
1228 if (strlen(buf) > PAXPATHLEN) {
1229 tty_prnt("File name too long, try again\n");
1230 continue;
1231 }
1232
1233 /*
1234 * try to open new archive
1235 */
1236 if (ar_open(buf) >= 0) {
1237 if (freeit) {
1238 (void)free((char *)(uintptr_t)arcname);
1239 freeit = 0;
1240 }
1241 if ((arcname = strdup(buf)) == NULL) {
1242 done = 1;
1243 lstrval = -1;
1244 paxwarn(0, "Cannot save archive name.");
1245 return(-1);
1246 }
1247 freeit = 1;
1248 break;
1249 }
1250 tty_prnt("Cannot open %s, try again\n", buf);
1251 continue;
1252 }
1253 return(0);
1254}
1255
1256/*
1257 * ar_start_gzip()
1258 * starts the gzip compression/decompression process as a child, using magic
1259 * to keep the fd the same in the calling function (parent).
1260 */
1261static void
1262ar_start_gzip(int fd, const char *gzip_prog, int wr)
1263{
1264 int fds[2];
1265 const char *gzip_flags;
1266
1267 if (pipe(fds) < 0)
1268 err(1, "could not pipe");
1269 zpid = fork();
1270 if (zpid < 0)
1271 err(1, "could not fork");
1272
1273 /* parent */
1274 if (zpid) {
1275 if (wr)
1276 dup2(fds[1], fd);
1277 else
1278 dup2(fds[0], fd);
1279 close(fds[0]);
1280 close(fds[1]);
1281 } else {
1282 if (wr) {
1283 dup2(fds[0], STDIN_FILENO);
1284 dup2(fd, STDOUT_FILENO);
1285 gzip_flags = "-c";
1286 } else {
1287 dup2(fds[1], STDOUT_FILENO);
1288 dup2(fd, STDIN_FILENO);
1289 gzip_flags = "-dc";
1290 }
1291 close(fds[0]);
1292 close(fds[1]);
1293 if (execlp(gzip_prog, gzip_prog, gzip_flags,
1294 (char *)NULL) < 0)
1295 err(1, "could not exec");
1296 /* NOTREACHED */
1297 }
1298}
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