1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
60 static char *bufpt;			/* read/write point in i/o buffer */
71  *	set up the buffering system to operate in a write mode
73  *	0 if ok, -1 if the user specified write block size violates pax spec
81 	 * Check to make sure the write block size meets pax specs. If the user  in wr_start()
88 		wrblksz = frmt->bsz;  in wr_start()
90 		paxwarn(1, "Write block size of %d too large, maximum is: %d",  in wr_start()
92 		return(-1);  in wr_start()
95 		paxwarn(1, "Write block size of %d is not a %d byte multiple",  in wr_start()
97 		return(-1);  in wr_start()
100 		paxwarn(0, "Write block size of %d larger than POSIX max %d, archive may not be portable",  in wr_start()
102 		return(-1);  in wr_start()
109 	if ((ar_open(arcname) < 0) && (ar_next() < 0))  in wr_start()
110 		return(-1);  in wr_start()
111 	wrcnt = 0;  in wr_start()
114 	return(0);  in wr_start()
121  *	0 if ok, -1 otherwise
129 	 * going to append and user specified a write block size, check it  in rd_start()
135 			paxwarn(1,"Write block size %d too large, maximum is: %d",  in rd_start()
137 			return(-1);  in rd_start()
140 			paxwarn(1, "Write block size %d is not a %d byte multiple",  in rd_start()
142 			return(-1);  in rd_start()
149 	if ((ar_open(arcname) < 0) && (ar_next() < 0))  in rd_start()
150 		return(-1);  in rd_start()
153 	rdcnt = 0;  in rd_start()
154 	return(0);  in rd_start()
179  *	position of the tape head) and the write point within the data we have
180  *	stored in the read (soon to become write) buffer. We may have to move
187  *	up. We set the buffer write pointer to be at this byte (the byte where
193  *	about the conditions under which they will allow a write to occur.
198  *	0 for success, -1 for failure
207 	if (exit_val != 0) {  in appnd_start()
208 		paxwarn(0, "Cannot append to an archive that may have flaws.");  in appnd_start()
209 		return(-1);  in appnd_start()
212 	 * if the user did not specify a write blocksize, inherit the size used  in appnd_start()
224 	if (ar_app_ok() < 0)  in appnd_start()
225 		return(-1);  in appnd_start()
233 	skcnt += bufend - bufpt;  in appnd_start()
236 	if (ar_rev((off_t)cnt) < 0)  in appnd_start()
244 	if ((cnt -= skcnt) > 0) {  in appnd_start()
254 			if ((res = ar_read(bufpt, rdblksz)) <= 0)  in appnd_start()
258 		if (ar_rev((off_t)(bufpt - buf)) < 0)  in appnd_start()
270 	rdcnt -= skcnt;  in appnd_start()
271 	wrcnt = 0;  in appnd_start()
274 	 * At this point we are ready to write. If the device requires special  in appnd_start()
275 	 * handling to write at a point were previously recorded data resides,  in appnd_start()
277 	 * ARCHIVE mode (write) conditions  in appnd_start()
279 	if (ar_set_wr() < 0)  in appnd_start()
280 		return(-1);  in appnd_start()
282 	return(0);  in appnd_start()
286 	return(-1);  in appnd_start()
297  *	0 on success, and -1 on failure
303 	int errcnt = 0;  in rd_sync()
309 	if (maxflt == 0)  in rd_sync()
310 		return(-1);  in rd_sync()
313 		return(-1);  in rd_sync()
319 	if (ar_rdsync() < 0) {  in rd_sync()
320 		if (ar_next() < 0)  in rd_sync()
321 			return(-1);  in rd_sync()
323 			rdcnt = 0;  in rd_sync()
327 		if ((res = ar_read(buf, blksz)) > 0) {  in rd_sync()
334 			return(0);  in rd_sync()
345 		if ((maxflt > 0) && (++errcnt > maxflt))  in rd_sync()
346 			paxwarn(0,"Archive read error limit (%d) reached",maxflt);  in rd_sync()
347 		else if (ar_rdsync() == 0)  in rd_sync()
349 		if (ar_next() < 0)  in rd_sync()
351 		rdcnt = 0;  in rd_sync()
352 		errcnt = 0;  in rd_sync()
354 	return(-1);  in rd_sync()
371 	bufpt -= cnt;  in pback()
381  *	0 if ok, -1 failure, and 1 when EOF on the archive volume was detected.
389 	off_t skipped = 0;  in rd_skip()
397 	if (skcnt == 0)  in rd_skip()
398 		return(0);  in rd_skip()
399 	res = MIN((bufend - bufpt), skcnt);  in rd_skip()
401 	skcnt -= res;  in rd_skip()
404 	 * if skcnt is now 0, then no additional i/o is needed  in rd_skip()
406 	if (skcnt == 0)  in rd_skip()
407 		return(0);  in rd_skip()
420 	if (ar_fow(cnt, &skipped) < 0)  in rd_skip()
421 		return(-1);  in rd_skip()
422 	res += cnt - skipped;  in rd_skip()
429 	while (res > 0L) {  in rd_skip()
430 		cnt = bufend - bufpt;  in rd_skip()
434 		if ((cnt <= 0) && ((cnt = buf_fill()) < 0))  in rd_skip()
435 			return(-1);  in rd_skip()
436 		if (cnt == 0)  in rd_skip()
440 		res -= cnt;  in rd_skip()
442 	return(0);  in rd_skip()
448  *	with zero (even though we do not have to). Padding with 0 makes it a
457 		memset(bufpt, 0, bufend - bufpt);  in wr_fin()
465  *	fill the write buffer from data passed to it in a buffer (usually used
466  *	by format specific write routines to pass a file header). On failure we
467  *	punt. We do not allow the user to continue to write flawed archives.
471  *	0 if buffer was filled ok, -1 o.w. (buffer flush failure)
480 	 * while there is data to copy into the write buffer. when the  in wr_rdbuf()
481 	 * write buffer fills, flush it to the archive and continue  in wr_rdbuf()
483 	while (outcnt > 0) {  in wr_rdbuf()
484 		cnt = bufend - bufpt;  in wr_rdbuf()
485 		if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0))  in wr_rdbuf()
486 			return(-1);  in wr_rdbuf()
494 		outcnt -= cnt;  in wr_rdbuf()
496 	return(0);  in wr_rdbuf()
506  *	number of bytes copied to the buffer, 0 indicates EOF on archive volume,
507  *	-1 is a read error
520 	while (incnt > 0) {  in rd_wrbuf()
521 		cnt = bufend - bufpt;  in rd_wrbuf()
522 		if ((cnt <= 0) && ((cnt = buf_fill()) <= 0)) {  in rd_wrbuf()
529 			if ((res = cpcnt - incnt) > 0)  in rd_wrbuf()
541 		incnt -= cnt;  in rd_wrbuf()
549  *	skip forward during a write. In other words add padding to the file.
555  *	0 if ok, -1 if there was a buf_flush failure
566 	while (skcnt > 0L) {  in wr_skip()
567 		cnt = bufend - bufpt;  in wr_skip()
568 		if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0))  in wr_skip()
569 			return(-1);  in wr_skip()
571 		memset(bufpt, 0, cnt);  in wr_skip()
573 		skcnt -= cnt;  in wr_skip()
575 	return(0);  in wr_skip()
580  *	fill write buffer with the contents of a file. We are passed an open
583  *	number of bytes of the file we were NOT able to write to the archive.
584  *	it is important that we always write EXACTLY the number of bytes that
585  *	the format specific write routine told us to. The file can also get
592  *	0 ok, -1 if archive write failure. a short read of the file returns a
593  *	0, but "left" is set to be greater than zero.
600 	int res = 0;  in wr_rdfile()
601 	off_t size = arcn->sb.st_size;  in wr_rdfile()
605 	 * while there are more bytes to write  in wr_rdfile()
607 	while (size > 0L) {  in wr_rdfile()
608 		cnt = bufend - bufpt;  in wr_rdfile()
609 		if ((cnt <= 0) && ((cnt = buf_flush(blksz)) < 0)) {  in wr_rdfile()
611 			return(-1);  in wr_rdfile()
614 		if ((res = read(ifd, bufpt, cnt)) <= 0)  in wr_rdfile()
616 		size -= res;  in wr_rdfile()
624 	if (res < 0)  in wr_rdfile()
625 		syswarn(1, errno, "Read fault on %s", arcn->org_name);  in wr_rdfile()
626 	else if (size != 0L)  in wr_rdfile()
627 		paxwarn(1, "File changed size during read %s", arcn->org_name);  in wr_rdfile()
628 	else if (fstat(ifd, &sb) < 0)  in wr_rdfile()
629 		syswarn(1, errno, "Failed stat on %s", arcn->org_name);  in wr_rdfile()
630 	else if (arcn->sb.st_mtime != sb.st_mtime)  in wr_rdfile()
632 			arcn->org_name);  in wr_rdfile()
634 	return(0);  in wr_rdfile()
640  *	extract the entire file (due to failure to write the file) we return
647  *	We call a special function to write the file. This function attempts to
653  *	0 ok, -1 if archive read failure. if we cannot write the entire file,
654  *	we return a 0 but "left" is set to be the amount unwritten
660 	int cnt = 0;  in rd_wrfile()
661 	off_t size = arcn->sb.st_size;  in rd_wrfile()
662 	int res = 0;  in rd_wrfile()
663 	char *fnm = arcn->name;  in rd_wrfile()
668 	u_long crc = 0L;  in rd_wrfile()
671 	 * pass the blocksize of the file being written to the write routine,  in rd_wrfile()
674 	if (fstat(ofd, &sb) == 0) {  in rd_wrfile()
675 		if (sb.st_blksize > 0)  in rd_wrfile()
678 		syswarn(0,errno,"Unable to obtain block size for file %s",fnm);  in rd_wrfile()
680 	*left = 0L;  in rd_wrfile()
687 	while (size > 0L) {  in rd_wrfile()
688 		cnt = bufend - bufpt;  in rd_wrfile()
691 		 * miss a header, so we do not set left, but if we get a write  in rd_wrfile()
694 		if ((cnt <= 0) && ((cnt = buf_fill()) <= 0))  in rd_wrfile()
697 		if ((res = file_write(ofd,bufpt,cnt,&rem,&isem,sz,fnm)) <= 0) {  in rd_wrfile()
707 			while (--cnt >= 0)  in rd_wrfile()
708 				crc += *bufpt++ & 0xff;  in rd_wrfile()
711 		size -= res;  in rd_wrfile()
720 	if (isem && (arcn->sb.st_size > 0L))  in rd_wrfile()
726 	if ((size > 0L) && (*left == 0L))  in rd_wrfile()
727 		return(-1);  in rd_wrfile()
733 	if (docrc && (size == 0L) && (arcn->crc != crc))  in rd_wrfile()
734 		paxwarn(1,"Actual crc does not match expected crc %s",arcn->name);  in rd_wrfile()
735 	return(0);  in rd_wrfile()
740  *	copy the contents of one file to another. used during -rw phase of pax
741  *	just as in rd_wrfile() we use a special write function to write the
749 	off_t cpcnt = 0L;  in cp_file()
750 	int res = 0;  in cp_file()
751 	char *fnm = arcn->name;  in cp_file()
752 	int no_hole = 0;  in cp_file()
760 	 * write instead of file write.  in cp_file()
762 	 if (((off_t)(arcn->sb.st_blocks * BLKMULT)) >= arcn->sb.st_size)  in cp_file()
766 	 * pass the blocksize of the file being written to the write routine,  in cp_file()
769 	if (fstat(fd2, &sb) == 0) {  in cp_file()
770 		if (sb.st_blksize > 0)  in cp_file()
773 		syswarn(0,errno,"Unable to obtain block size for file %s",fnm);  in cp_file()
780 		if ((cnt = read(fd1, buf, blksz)) <= 0)  in cp_file()
783 			res = write(fd2, buf, cnt);  in cp_file()
794 	if (res < 0)  in cp_file()
795 		syswarn(1, errno, "Failed write during copy of %s to %s",  in cp_file()
796 			arcn->org_name, arcn->name);  in cp_file()
797 	else if (cpcnt != arcn->sb.st_size)  in cp_file()
799 			arcn->org_name, arcn->name);  in cp_file()
800 	else if (fstat(fd1, &sb) < 0)  in cp_file()
801 		syswarn(1, errno, "Failed stat of %s", arcn->org_name);  in cp_file()
802 	else if (arcn->sb.st_mtime != sb.st_mtime)  in cp_file()
804 			arcn->org_name, arcn->name);  in cp_file()
812 	if (!no_hole && isem && (arcn->sb.st_size > 0L))  in cp_file()
822  *	Number of bytes of data in the read buffer, -1 for read error, and
823  *	0 when finished (user specified termination in ar_next()).
830 	static int fini = 0;  in buf_fill()
833 		return(0);  in buf_fill()
840 		if ((cnt = ar_read(buf, blksz)) > 0) {  in buf_fill()
853 		if (cnt < 0)  in buf_fill()
855 		if (frmt == NULL || ar_next() < 0) {  in buf_fill()
857 			return(0);  in buf_fill()
859 		rdcnt = 0;  in buf_fill()
862 	return(-1);  in buf_fill()
867  *	force the write buffer to the archive. We are passed the number of
871  *	0 if all is ok, -1 when a write error occurs.
878 	int push = 0;  in buf_flush()
879 	int totcnt = 0;  in buf_flush()
883 	 * volume, prompt for the next volume. (The non-standard -R flag).  in buf_flush()
884 	 * NOTE: If the wrlimit is smaller than wrcnt, we will always write  in buf_flush()
887 	if ((wrlimit > 0) && (wrcnt > wrlimit)) {  in buf_flush()
888 		paxwarn(0, "User specified archive volume byte limit reached.");  in buf_flush()
889 		if (ar_next() < 0) {  in buf_flush()
890 			wrcnt = 0;  in buf_flush()
892 			return(-1);  in buf_flush()
894 		wrcnt = 0;  in buf_flush()
898 		 * write blocksize. if so we figure out if we need to write  in buf_flush()
907 			return(0);  in buf_flush()
909 			push = bufcnt - blksz;  in buf_flush()
913 	 * We have enough data to write at least one archive block  in buf_flush()
917 		 * write a block and check if it all went out ok  in buf_flush()
922 			 * the write went ok  in buf_flush()
926 			if (push > 0) {  in buf_flush()
929 				 * so we loop back to write again  in buf_flush()
934 					push -= blksz;  in buf_flush()
940 		} else if (cnt > 0) {  in buf_flush()
942 			 * Oh drat we got a partial write!  in buf_flush()
950 			cnt = bufcnt - cnt;  in buf_flush()
953 			if (!frmt->blkalgn || ((cnt % frmt->blkalgn) == 0))  in buf_flush()
961 		wrcnt = 0;  in buf_flush()
962 		if (ar_next() < 0)  in buf_flush()
972 			return(0);  in buf_flush()
974 			push = bufcnt - blksz;  in buf_flush()
978 	 * write failed, stop pax. we must not create a bad archive!  in buf_flush()
981 	return(-1);  in buf_flush()