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