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 * %sccs.include.redist.c%
10 */
11
12 #ifndef lint
13 static char sccsid[] = "@(#)buf_subs.c 8.2 (Berkeley) 04/18/94";
14 #endif /* not lint */
15
16 #include <sys/types.h>
17 #include <sys/time.h>
18 #include <sys/stat.h>
19 #include <sys/param.h>
20 #include <stdio.h>
21 #include <ctype.h>
22 #include <errno.h>
23 #include <unistd.h>
24 #include <stdlib.h>
25 #include <string.h>
26 #include "pax.h"
27 #include "extern.h"
28
29 /*
30 * routines which implement archive and file buffering
31 */
32
33 #define MINFBSZ 512 /* default block size for hole detect */
34 #define MAXFLT 10 /* default media read error limit */
35
36 /*
37 * Need to change bufmem to dynamic allocation when the upper
38 * limit on blocking size is removed (though that will violate pax spec)
39 * MAXBLK define and tests will also need to be updated.
40 */
41 static char bufmem[MAXBLK+BLKMULT]; /* i/o buffer + pushback id space */
42 static char *buf; /* normal start of i/o buffer */
43 static char *bufend; /* end or last char in i/o buffer */
44 static char *bufpt; /* read/write point in i/o buffer */
45 int blksz = MAXBLK; /* block input/output size in bytes */
46 int wrblksz; /* user spec output size in bytes */
47 int maxflt = MAXFLT; /* MAX consecutive media errors */
48 int rdblksz; /* first read blksize (tapes only) */
49 off_t wrlimit; /* # of bytes written per archive vol */
50 off_t wrcnt; /* # of bytes written on current vol */
51 off_t rdcnt; /* # of bytes read on current vol */
52
53 /*
54 * wr_start()
55 * set up the buffering system to operate in a write mode
56 * Return:
57 * 0 if ok, -1 if the user specified write block size violates pax spec
58 */
59
60 #if __STDC__
61 int
wr_start(void)62 wr_start(void)
63 #else
64 int
65 wr_start()
66 #endif
67 {
68 buf = &(bufmem[BLKMULT]);
69 /*
70 * Check to make sure the write block size meets pax specs. If the user
71 * does not specify a blocksize, we use the format default blocksize.
72 * We must be picky on writes, so we do not allow the user to create an
73 * archive that might be hard to read elsewhere. If all ok, we then
74 * open the first archive volume
75 */
76 if (!wrblksz)
77 wrblksz = frmt->bsz;
78 if (wrblksz > MAXBLK) {
79 warn(1, "Write block size of %d too large, maximium is: %d",
80 wrblksz, MAXBLK);
81 return(-1);
82 }
83 if (wrblksz % BLKMULT) {
84 warn(1, "Write block size of %d is not a %d byte multiple",
85 wrblksz, BLKMULT);
86 return(-1);
87 }
88
89 /*
90 * we only allow wrblksz to be used with all archive operations
91 */
92 blksz = rdblksz = wrblksz;
93 if ((ar_open(arcname) < 0) && (ar_next() < 0))
94 return(-1);
95 wrcnt = 0;
96 bufend = buf + wrblksz;
97 bufpt = buf;
98 return(0);
99 }
100
101 /*
102 * rd_start()
103 * set up buffering system to read an archive
104 * Return:
105 * 0 if ok, -1 otherwise
106 */
107
108 #if __STDC__
109 int
rd_start(void)110 rd_start(void)
111 #else
112 int
113 rd_start()
114 #endif
115 {
116 /*
117 * leave space for the header pushback (see get_arc()). If we are
118 * going to append and user specified a write block size, check it
119 * right away
120 */
121 buf = &(bufmem[BLKMULT]);
122 if ((act == APPND) && wrblksz) {
123 if (wrblksz > MAXBLK) {
124 warn(1,"Write block size %d too large, maximium is: %d",
125 wrblksz, MAXBLK);
126 return(-1);
127 }
128 if (wrblksz % BLKMULT) {
129 warn(1, "Write block size %d is not a %d byte multiple",
130 wrblksz, BLKMULT);
131 return(-1);
132 }
133 }
134
135 /*
136 * open the archive
137 */
138 if ((ar_open(arcname) < 0) && (ar_next() < 0))
139 return(-1);
140 bufend = buf + rdblksz;
141 bufpt = bufend;
142 rdcnt = 0;
143 return(0);
144 }
145
146 /*
147 * cp_start()
148 * set up buffer system for copying within the file system
149 */
150
151 #if __STDC__
152 void
cp_start(void)153 cp_start(void)
154 #else
155 void
156 cp_start()
157 #endif
158 {
159 buf = &(bufmem[BLKMULT]);
160 rdblksz = blksz = MAXBLK;
161 }
162
163 /*
164 * appnd_start()
165 * Set up the buffering system to append new members to an archive that
166 * was just read. The last block(s) of an archive may contain a format
167 * specific trailer. To append a new member, this trailer has to be
168 * removed from the archive. The first byte of the trailer is replaced by
169 * the start of the header of the first file added to the archive. The
170 * format specific end read function tells us how many bytes to move
171 * backwards in the archive to be positioned BEFORE the trailer. Two
172 * different postions have to be adjusted, the O.S. file offset (e.g. the
173 * position of the tape head) and the write point within the data we have
174 * stored in the read (soon to become write) buffer. We may have to move
175 * back several records (the number depends on the size of the archive
176 * record and the size of the format trailer) to read up the record where
177 * the first byte of the trailer is recorded. Trailers may span (and
178 * overlap) record boundries.
179 * We first calculate which record has the first byte of the trailer. We
180 * move the OS file offset back to the start of this record and read it
181 * up. We set the buffer write pointer to be at this byte (the byte where
182 * the trailer starts). We then move the OS file pointer back to the
183 * start of this record so a flush of this buffer will replace the record
184 * in the archive.
185 * A major problem is rewriting this last record. For archives stored
186 * on disk files, this is trival. However, many devices are really picky
187 * about the conditions under which they will allow a write to occur.
188 * Often devices restrict the conditions where writes can be made writes,
189 * so it may not be feasable to append archives stored on all types of
190 * devices.
191 * Return:
192 * 0 for success, -1 for failure
193 */
194
195 #if __STDC__
196 int
appnd_start(off_t skcnt)197 appnd_start(off_t skcnt)
198 #else
199 int
200 appnd_start(skcnt)
201 off_t skcnt;
202 #endif
203 {
204 register int res;
205 off_t cnt;
206
207 if (exit_val != 0) {
208 warn(0, "Cannot append to an archive that may have flaws.");
209 return(-1);
210 }
211 /*
212 * if the user did not specify a write blocksize, inherit the size used
213 * in the last archive volume read. (If a is set we still use rdblksz
214 * until next volume, cannot shift sizes within a single volume).
215 */
216 if (!wrblksz)
217 wrblksz = blksz = rdblksz;
218 else
219 blksz = rdblksz;
220
221 /*
222 * make sure that this volume allows appends
223 */
224 if (ar_app_ok() < 0)
225 return(-1);
226
227 /*
228 * Calculate bytes to move back and move in front of record where we
229 * need to start writing from. Remember we have to add in any padding
230 * that might be in the buffer after the trailer in the last block. We
231 * travel skcnt + padding ROUNDED UP to blksize.
232 */
233 skcnt += bufend - bufpt;
234 if ((cnt = (skcnt/blksz) * blksz) < skcnt)
235 cnt += blksz;
236 if (ar_rev((off_t)cnt) < 0)
237 goto out;
238
239 /*
240 * We may have gone too far if there is valid data in the block we are
241 * now in front of, read up the block and position the pointer after
242 * the valid data.
243 */
244 if ((cnt -= skcnt) > 0) {
245 /*
246 * watch out for stupid tape drives. ar_rev() will set rdblksz
247 * to be real physical blocksize so we must loop until we get
248 * the old rdblksz (now in blksz). If ar_rev() fouls up the
249 * determination of the physical block size, we will fail.
250 */
251 bufpt = buf;
252 bufend = buf + blksz;
253 while (bufpt < bufend) {
254 if ((res = ar_read(bufpt, rdblksz)) <= 0)
255 goto out;
256 bufpt += res;
257 }
258 if (ar_rev((off_t)(bufpt - buf)) < 0)
259 goto out;
260 bufpt = buf + cnt;
261 bufend = buf + blksz;
262 } else {
263 /*
264 * buffer is empty
265 */
266 bufend = buf + blksz;
267 bufpt = buf;
268 }
269 rdblksz = blksz;
270 rdcnt -= skcnt;
271 wrcnt = 0;
272
273 /*
274 * At this point we are ready to write. If the device requires special
275 * handling to write at a point were previously recorded data resides,
276 * that is handled in ar_set_wr(). From now on we operate under normal
277 * ARCHIVE mode (write) conditions
278 */
279 if (ar_set_wr() < 0)
280 return(-1);
281 act = ARCHIVE;
282 return(0);
283
284 out:
285 warn(1, "Unable to rewrite archive trailer, cannot append.");
286 return(-1);
287 }
288
289 /*
290 * rd_sync()
291 * A read error occurred on this archive volume. Resync the buffer and
292 * try to reset the device (if possible) so we can continue to read. Keep
293 * trying to do this until we get a valid read, or we reach the limit on
294 * consecutive read faults (at which point we give up). The user can
295 * adjust the read error limit through a command line option.
296 * Returns:
297 * 0 on success, and -1 on failure
298 */
299
300 #if __STDC__
301 int
rd_sync(void)302 rd_sync(void)
303 #else
304 int
305 rd_sync()
306 #endif
307 {
308 register int errcnt = 0;
309 register int res;
310
311 /*
312 * if the user says bail out on first fault, we are out of here...
313 */
314 if (maxflt == 0)
315 return(-1);
316 if (act == APPND) {
317 warn(1, "Unable to append when there are archive read errors.");
318 return(-1);
319 }
320
321 /*
322 * poke at device and try to get past media error
323 */
324 if (ar_rdsync() < 0) {
325 if (ar_next() < 0)
326 return(-1);
327 else
328 rdcnt = 0;
329 }
330
331 for (;;) {
332 if ((res = ar_read(buf, blksz)) > 0) {
333 /*
334 * All right! got some data, fill that buffer
335 */
336 bufpt = buf;
337 bufend = buf + res;
338 rdcnt += res;
339 return(0);
340 }
341
342 /*
343 * Oh well, yet another failed read...
344 * if error limit reached, ditch. o.w. poke device to move past
345 * bad media and try again. if media is badly damaged, we ask
346 * the poor (and upset user at this point) for the next archive
347 * volume. remember the goal on reads is to get the most we
348 * can extract out of the archive.
349 */
350 if ((maxflt > 0) && (++errcnt > maxflt))
351 warn(0,"Archive read error limit (%d) reached",maxflt);
352 else if (ar_rdsync() == 0)
353 continue;
354 if (ar_next() < 0)
355 break;
356 rdcnt = 0;
357 errcnt = 0;
358 }
359 return(-1);
360 }
361
362 /*
363 * pback()
364 * push the data used during the archive id phase back into the I/O
365 * buffer. This is required as we cannot be sure that the header does NOT
366 * overlap a block boundry (as in the case we are trying to recover a
367 * flawed archived). This was not designed to be used for any other
368 * purpose. (What software engineering, HA!)
369 * WARNING: do not even THINK of pback greater than BLKMULT, unless the
370 * pback space is increased.
371 */
372
373 #if __STDC__
374 void
pback(char * pt,int cnt)375 pback(char *pt, int cnt)
376 #else
377 void
378 pback(pt, cnt)
379 char *pt;
380 int cnt;
381 #endif
382 {
383 bufpt -= cnt;
384 bcopy(pt, bufpt, cnt);
385 return;
386 }
387
388 /*
389 * rd_skip()
390 * skip foward in the archive during a archive read. Used to get quickly
391 * past file data and padding for files the user did NOT select.
392 * Return:
393 * 0 if ok, -1 failure, and 1 when EOF on the archive volume was detected.
394 */
395
396 #if __STDC__
397 int
rd_skip(off_t skcnt)398 rd_skip(off_t skcnt)
399 #else
400 int
401 rd_skip(skcnt)
402 off_t skcnt;
403 #endif
404 {
405 off_t res;
406 off_t cnt;
407 off_t skipped = 0;
408
409 /*
410 * consume what data we have in the buffer. If we have to move foward
411 * whole records, we call the low level skip function to see if we can
412 * move within the archive without doing the expensive reads on data we
413 * do not want.
414 */
415 if (skcnt == 0)
416 return(0);
417 res = MIN((bufend - bufpt), skcnt);
418 bufpt += res;
419 skcnt -= res;
420
421 /*
422 * if skcnt is now 0, then no additional i/o is needed
423 */
424 if (skcnt == 0)
425 return(0);
426
427 /*
428 * We have to read more, calculate complete and partial record reads
429 * based on rdblksz. we skip over "cnt" complete records
430 */
431 res = skcnt%rdblksz;
432 cnt = (skcnt/rdblksz) * rdblksz;
433
434 /*
435 * if the skip fails, we will have to resync. ar_fow will tell us
436 * how much it can skip over. We will have to read the rest.
437 */
438 if (ar_fow(cnt, &skipped) < 0)
439 return(-1);
440 res += cnt - skipped;
441 rdcnt += skipped;
442
443 /*
444 * what is left we have to read (which may be the whole thing if
445 * ar_fow() told us the device can only read to skip records);
446 */
447 while (res > 0L) {
448 cnt = bufend - bufpt;
449 /*
450 * if the read fails, we will have to resync
451 */
452 if ((cnt <= 0) && ((cnt = buf_fill()) < 0))
453 return(-1);
454 if (cnt == 0)
455 return(1);
456 cnt = MIN(cnt, res);
457 bufpt += cnt;
458 res -= cnt;
459 }
460 return(0);
461 }
462
463 /*
464 * wr_fin()
465 * flush out any data (and pad if required) the last block. We always pad
466 * with zero (even though we do not have to). Padding with 0 makes it a
467 * lot easier to recover if the archive is damaged. zero paddding SHOULD
468 * BE a requirement....
469 */
470
471 #if __STDC__
472 void
wr_fin(void)473 wr_fin(void)
474 #else
475 void
476 wr_fin()
477 #endif
478 {
479 if (bufpt > buf) {
480 bzero(bufpt, bufend - bufpt);
481 bufpt = bufend;
482 (void)buf_flush(blksz);
483 }
484 }
485
486 /*
487 * wr_rdbuf()
488 * fill the write buffer from data passed to it in a buffer (usually used
489 * by format specific write routines to pass a file header). On failure we
490 * punt. We do not allow the user to continue to write flawed archives.
491 * We assume these headers are not very large (the memory copy we use is
492 * a bit expensive).
493 * Return:
494 * 0 if buffer was filled ok, -1 o.w. (buffer flush failure)
495 */
496
497 #if __STDC__
498 int
wr_rdbuf(register char * out,register int outcnt)499 wr_rdbuf(register char *out, register int outcnt)
500 #else
501 int
502 wr_rdbuf(out, outcnt)
503 register char *out;
504 register int outcnt;
505 #endif
506 {
507 register int cnt;
508
509 /*
510 * while there is data to copy copy into the write buffer. when the
511 * write buffer fills, flush it to the archive and continue
512 */
513 while (outcnt > 0) {
514 cnt = bufend - bufpt;
515 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0))
516 return(-1);
517 /*
518 * only move what we have space for
519 */
520 cnt = MIN(cnt, outcnt);
521 bcopy(out, bufpt, cnt);
522 bufpt += cnt;
523 out += cnt;
524 outcnt -= cnt;
525 }
526 return(0);
527 }
528
529 /*
530 * rd_wrbuf()
531 * copy from the read buffer into a supplied buffer a specified number of
532 * bytes. If the read buffer is empty fill it and continue to copy.
533 * usually used to obtain a file header for processing by a format
534 * specific read routine.
535 * Return
536 * number of bytes copied to the buffer, 0 indicates EOF on archive volume,
537 * -1 is a read error
538 */
539
540 #if __STDC__
541 int
rd_wrbuf(register char * in,register int cpcnt)542 rd_wrbuf(register char *in, register int cpcnt)
543 #else
544 int
545 rd_wrbuf(in, cpcnt)
546 register char *in;
547 register int cpcnt;
548 #endif
549 {
550 register int res;
551 register int cnt;
552 register int incnt = cpcnt;
553
554 /*
555 * loop until we fill the buffer with the requested number of bytes
556 */
557 while (incnt > 0) {
558 cnt = bufend - bufpt;
559 if ((cnt <= 0) && ((cnt = buf_fill()) <= 0)) {
560 /*
561 * read error, return what we got (or the error if
562 * no data was copied). The caller must know that an
563 * error occured and has the best knowledge what to
564 * do with it
565 */
566 if ((res = cpcnt - incnt) > 0)
567 return(res);
568 return(cnt);
569 }
570
571 /*
572 * calculate how much data to copy based on whats left and
573 * state of buffer
574 */
575 cnt = MIN(cnt, incnt);
576 bcopy(bufpt, in, cnt);
577 bufpt += cnt;
578 incnt -= cnt;
579 in += cnt;
580 }
581 return(cpcnt);
582 }
583
584 /*
585 * wr_skip()
586 * skip foward during a write. In other words add padding to the file.
587 * we add zero filled padding as it makes flawed archives much easier to
588 * recover from. the caller tells us how many bytes of padding to add
589 * This routine was not designed to add HUGE amount of padding, just small
590 * amounts (a few 512 byte blocks at most)
591 * Return:
592 * 0 if ok, -1 if there was a buf_flush failure
593 */
594
595 #if __STDC__
596 int
wr_skip(off_t skcnt)597 wr_skip(off_t skcnt)
598 #else
599 int
600 wr_skip(skcnt)
601 off_t skcnt;
602 #endif
603 {
604 register int cnt;
605
606 /*
607 * loop while there is more padding to add
608 */
609 while (skcnt > 0L) {
610 cnt = bufend - bufpt;
611 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0))
612 return(-1);
613 cnt = MIN(cnt, skcnt);
614 bzero(bufpt, cnt);
615 bufpt += cnt;
616 skcnt -= cnt;
617 }
618 return(0);
619 }
620
621 /*
622 * wr_rdfile()
623 * fill write buffer with the contents of a file. We are passed an open
624 * file descriptor to the file an the archive structure that describes the
625 * file we are storing. The variable "left" is modified to contain the
626 * number of bytes of the file we were NOT able to write to the archive.
627 * it is important that we always write EXACTLY the number of bytes that
628 * the format specific write routine told us to. The file can also get
629 * bigger, so reading to the end of file would create an improper archive,
630 * we just detect this case and warn the user. We never create a bad
631 * archive if we can avoid it. Of course trying to archive files that are
632 * active is asking for trouble. It we fail, we pass back how much we
633 * could NOT copy and let the caller deal with it.
634 * Return:
635 * 0 ok, -1 if archive write failure. a short read of the file returns a
636 * 0, but "left" is set to be greater than zero.
637 */
638
639 #if __STDC__
640 int
wr_rdfile(ARCHD * arcn,int ifd,off_t * left)641 wr_rdfile(ARCHD *arcn, int ifd, off_t *left)
642 #else
643 int
644 wr_rdfile(arcn, ifd, left)
645 ARCHD *arcn;
646 int ifd;
647 off_t *left;
648 #endif
649 {
650 register int cnt;
651 register int res = 0;
652 register off_t size = arcn->sb.st_size;
653 struct stat sb;
654
655 /*
656 * while there are more bytes to write
657 */
658 while (size > 0L) {
659 cnt = bufend - bufpt;
660 if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0)) {
661 *left = size;
662 return(-1);
663 }
664 cnt = MIN(cnt, size);
665 if ((res = read(ifd, bufpt, cnt)) <= 0)
666 break;
667 size -= res;
668 bufpt += res;
669 }
670
671 /*
672 * better check the file did not change during this operation
673 * or the file read failed.
674 */
675 if (res < 0)
676 syswarn(1, errno, "Read fault on %s", arcn->org_name);
677 else if (size != 0L)
678 warn(1, "File changed size during read %s", arcn->org_name);
679 else if (fstat(ifd, &sb) < 0)
680 syswarn(1, errno, "Failed stat on %s", arcn->org_name);
681 else if (arcn->sb.st_mtime != sb.st_mtime)
682 warn(1, "File %s was modified during copy to archive",
683 arcn->org_name);
684 *left = size;
685 return(0);
686 }
687
688 /*
689 * rd_wrfile()
690 * extract the contents of a file from the archive. If we are unable to
691 * extract the entire file (due to failure to write the file) we return
692 * the numbers of bytes we did NOT process. This way the caller knows how
693 * many bytes to skip past to find the next archive header. If the failure
694 * was due to an archive read, we will catch that when we try to skip. If
695 * the format supplies a file data crc value, we calculate the actual crc
696 * so that it can be compared to the value stored in the header
697 * NOTE:
698 * We call a special function to write the file. This function attempts to
699 * restore file holes (blocks of zeros) into the file. When files are
700 * sparse this saves space, and is a LOT faster. For non sparse files
701 * the performance hit is small. As of this writing, no archive supports
702 * information on where the file holes are.
703 * Return:
704 * 0 ok, -1 if archive read failure. if we cannot write the entire file,
705 * we return a 0 but "left" is set to be the amount unwritten
706 */
707
708 #if __STDC__
709 int
rd_wrfile(ARCHD * arcn,int ofd,off_t * left)710 rd_wrfile(ARCHD *arcn, int ofd, off_t *left)
711 #else
712 int
713 rd_wrfile(arcn, ofd, left)
714 ARCHD *arcn;
715 int ofd;
716 off_t *left;
717 #endif
718 {
719 register int cnt = 0;
720 register off_t size = arcn->sb.st_size;
721 register int res = 0;
722 register char *fnm = arcn->name;
723 int isem = 1;
724 int rem;
725 int sz = MINFBSZ;
726 struct stat sb;
727 u_long crc = 0L;
728
729 /*
730 * pass the blocksize of the file being written to the write routine,
731 * if the size is zero, use the default MINFBSZ
732 */
733 if (fstat(ofd, &sb) == 0) {
734 if (sb.st_blksize > 0)
735 sz = (int)sb.st_blksize;
736 } else
737 syswarn(0,errno,"Unable to obtain block size for file %s",fnm);
738 rem = sz;
739 *left = 0L;
740
741 /*
742 * Copy the archive to the file the number of bytes specified. We have
743 * to assume that we want to recover file holes as none of the archive
744 * formats can record the location of file holes.
745 */
746 while (size > 0L) {
747 cnt = bufend - bufpt;
748 /*
749 * if we get a read error, we do not want to skip, as we may
750 * miss a header, so we do not set left, but if we get a write
751 * error, we do want to skip over the unprocessed data.
752 */
753 if ((cnt <= 0) && ((cnt = buf_fill()) <= 0))
754 break;
755 cnt = MIN(cnt, size);
756 if ((res = file_write(ofd,bufpt,cnt,&rem,&isem,sz,fnm)) <= 0) {
757 *left = size;
758 break;
759 }
760
761 if (docrc) {
762 /*
763 * update the actual crc value
764 */
765 cnt = res;
766 while (--cnt >= 0)
767 crc += *bufpt++ & 0xff;
768 } else
769 bufpt += res;
770 size -= res;
771 }
772
773 /*
774 * if the last block has a file hole (all zero), we must make sure this
775 * gets updated in the file. We force the last block of zeros to be
776 * written. just closing with the file offset moved foward may not put
777 * a hole at the end of the file.
778 */
779 if (isem && (arcn->sb.st_size > 0L))
780 file_flush(ofd, fnm, isem);
781
782 /*
783 * if we failed from archive read, we do not want to skip
784 */
785 if ((size > 0L) && (*left == 0L))
786 return(-1);
787
788 /*
789 * some formats record a crc on file data. If so, then we compare the
790 * calculated crc to the crc stored in the archive
791 */
792 if (docrc && (size == 0L) && (arcn->crc != crc))
793 warn(1,"Actual crc does not match expected crc %s",arcn->name);
794 return(0);
795 }
796
797 /*
798 * cp_file()
799 * copy the contents of one file to another. used during -rw phase of pax
800 * just as in rd_wrfile() we use a special write function to write the
801 * destination file so we can properly copy files with holes.
802 */
803
804 #if __STDC__
805 void
cp_file(ARCHD * arcn,int fd1,int fd2)806 cp_file(ARCHD *arcn, int fd1, int fd2)
807 #else
808 void
809 cp_file(arcn, fd1, fd2)
810 ARCHD *arcn;
811 int fd1;
812 int fd2;
813 #endif
814 {
815 register int cnt;
816 register off_t cpcnt = 0L;
817 register int res = 0;
818 register char *fnm = arcn->name;
819 register int no_hole = 0;
820 int isem = 1;
821 int rem;
822 int sz = MINFBSZ;
823 struct stat sb;
824
825 /*
826 * check for holes in the source file. If none, we will use regular
827 * write instead of file write.
828 */
829 if (((off_t)(arcn->sb.st_blocks * BLKMULT)) >= arcn->sb.st_size)
830 ++no_hole;
831
832 /*
833 * pass the blocksize of the file being written to the write routine,
834 * if the size is zero, use the default MINFBSZ
835 */
836 if (fstat(fd2, &sb) == 0) {
837 if (sb.st_blksize > 0)
838 sz = sb.st_blksize;
839 } else
840 syswarn(0,errno,"Unable to obtain block size for file %s",fnm);
841 rem = sz;
842
843 /*
844 * read the source file and copy to destination file until EOF
845 */
846 for(;;) {
847 if ((cnt = read(fd1, buf, blksz)) <= 0)
848 break;
849 if (no_hole)
850 res = write(fd2, buf, cnt);
851 else
852 res = file_write(fd2, buf, cnt, &rem, &isem, sz, fnm);
853 if (res != cnt)
854 break;
855 cpcnt += cnt;
856 }
857
858 /*
859 * check to make sure the copy is valid.
860 */
861 if (res < 0)
862 syswarn(1, errno, "Failed write during copy of %s to %s",
863 arcn->org_name, arcn->name);
864 else if (cpcnt != arcn->sb.st_size)
865 warn(1, "File %s changed size during copy to %s",
866 arcn->org_name, arcn->name);
867 else if (fstat(fd1, &sb) < 0)
868 syswarn(1, errno, "Failed stat of %s", arcn->org_name);
869 else if (arcn->sb.st_mtime != sb.st_mtime)
870 warn(1, "File %s was modified during copy to %s",
871 arcn->org_name, arcn->name);
872
873 /*
874 * if the last block has a file hole (all zero), we must make sure this
875 * gets updated in the file. We force the last block of zeros to be
876 * written. just closing with the file offset moved foward may not put
877 * a hole at the end of the file.
878 */
879 if (!no_hole && isem && (arcn->sb.st_size > 0L))
880 file_flush(fd2, fnm, isem);
881 return;
882 }
883
884 /*
885 * buf_fill()
886 * fill the read buffer with the next record (or what we can get) from
887 * the archive volume.
888 * Return:
889 * Number of bytes of data in the read buffer, -1 for read error, and
890 * 0 when finished (user specified termination in ar_next()).
891 */
892
893 #if __STDC__
894 int
buf_fill(void)895 buf_fill(void)
896 #else
897 int
898 buf_fill()
899 #endif
900 {
901 register int cnt;
902 static int fini = 0;
903
904 if (fini)
905 return(0);
906
907 for(;;) {
908 /*
909 * try to fill the buffer. on error the next archive volume is
910 * opened and we try again.
911 */
912 if ((cnt = ar_read(buf, blksz)) > 0) {
913 bufpt = buf;
914 bufend = buf + cnt;
915 rdcnt += cnt;
916 return(cnt);
917 }
918
919 /*
920 * errors require resync, EOF goes to next archive
921 */
922 if (cnt < 0)
923 break;
924 if (ar_next() < 0) {
925 fini = 1;
926 return(0);
927 }
928 rdcnt = 0;
929 }
930 exit_val = 1;
931 return(-1);
932 }
933
934 /*
935 * buf_flush()
936 * force the write buffer to the archive. We are passed the number of
937 * bytes in the buffer at the point of the flush. When we change archives
938 * the record size might change. (either larger or smaller).
939 * Return:
940 * 0 if all is ok, -1 when a write error occurs.
941 */
942
943 #if __STDC__
944 int
buf_flush(register int bufcnt)945 buf_flush(register int bufcnt)
946 #else
947 int
948 buf_flush(bufcnt)
949 register int bufcnt;
950 #endif
951 {
952 register int cnt;
953 register int push = 0;
954 register int totcnt = 0;
955
956 /*
957 * if we have reached the user specified byte count for each archive
958 * volume, prompt for the next volume. (The non-standrad -R flag).
959 * NOTE: If the wrlimit is smaller than wrcnt, we will always write
960 * at least one record. We always round limit UP to next blocksize.
961 */
962 if ((wrlimit > 0) && (wrcnt > wrlimit)) {
963 warn(0, "User specified archive volume byte limit reached.");
964 if (ar_next() < 0) {
965 wrcnt = 0;
966 exit_val = 1;
967 return(-1);
968 }
969 wrcnt = 0;
970
971 /*
972 * The new archive volume might have changed the size of the
973 * write blocksize. if so we figure out if we need to write
974 * (one or more times), or if there is now free space left in
975 * the buffer (it is no longer full). bufcnt has the number of
976 * bytes in the buffer, (the blocksize, at the point we were
977 * CALLED). Push has the amount of "extra" data in the buffer
978 * if the block size has shrunk from a volume change.
979 */
980 bufend = buf + blksz;
981 if (blksz > bufcnt)
982 return(0);
983 if (blksz < bufcnt)
984 push = bufcnt - blksz;
985 }
986
987 /*
988 * We have enough data to write at least one archive block
989 */
990 for (;;) {
991 /*
992 * write a block and check if it all went out ok
993 */
994 cnt = ar_write(buf, blksz);
995 if (cnt == blksz) {
996 /*
997 * the write went ok
998 */
999 wrcnt += cnt;
1000 totcnt += cnt;
1001 if (push > 0) {
1002 /* we have extra data to push to the front.
1003 * check for more than 1 block of push, and if
1004 * so we loop back to write again
1005 */
1006 bcopy(bufend, buf, push);
1007 bufpt = buf + push;
1008 if (push >= blksz) {
1009 push -= blksz;
1010 continue;
1011 }
1012 } else
1013 bufpt = buf;
1014 return(totcnt);
1015 } else if (cnt > 0) {
1016 /*
1017 * Oh drat we got a partial write!
1018 * if format doesnt care about alignment let it go,
1019 * we warned the user in ar_write().... but this means
1020 * the last record on this volume violates pax spec....
1021 */
1022 totcnt += cnt;
1023 wrcnt += cnt;
1024 bufpt = buf + cnt;
1025 cnt = bufcnt - cnt;
1026 bcopy(bufpt, buf, cnt);
1027 bufpt = buf + cnt;
1028 if (!frmt->blkalgn || ((cnt % frmt->blkalgn) == 0))
1029 return(totcnt);
1030 break;
1031 }
1032
1033 /*
1034 * All done, go to next archive
1035 */
1036 wrcnt = 0;
1037 if (ar_next() < 0)
1038 break;
1039
1040 /*
1041 * The new archive volume might also have changed the block
1042 * size. if so, figure out if we have too much or too little
1043 * data for using the new block size
1044 */
1045 bufend = buf + blksz;
1046 if (blksz > bufcnt)
1047 return(0);
1048 if (blksz < bufcnt)
1049 push = bufcnt - blksz;
1050 }
1051
1052 /*
1053 * write failed, stop pax. we must not create a bad archive!
1054 */
1055 exit_val = 1;
1056 return(-1);
1057 }
1058