1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50 #define MAXFLT		10		/* default media read error limit */
60 static char *bufpt;			/* read/write point in i/o buffer */
64 int rdblksz;				/* first read blksize (tapes only) */
67 off_t rdcnt;				/* # of bytes read on current vol */
73  *	0 if ok, -1 if the user specified write block size violates pax spec
84 	 * archive that might be hard to read elsewhere. If all ok, we then  in wr_start()
88 		wrblksz = frmt->bsz;  in wr_start()
92 		return(-1);  in wr_start()
97 		return(-1);  in wr_start()
102 		return(-1);  in wr_start()
110 		return(-1);  in wr_start()
119  *	set up buffering system to read an archive
121  *	0 if ok, -1 otherwise
137 			return(-1);  in rd_start()
142 			return(-1);  in rd_start()
150 		return(-1);  in rd_start()
172  *	was just read. The last block(s) of an archive may contain a format
176  *	format specific end read function tells us how many bytes to move
180  *	stored in the read (soon to become write) buffer. We may have to move
182  *	record and the size of the format trailer) to read up the record where
186  *	move the OS file offset back to the start of this record and read it
198  *	0 for success, -1 for failure
209 		return(-1);  in appnd_start()
213 	 * in the last archive volume read. (If a is set we still use rdblksz  in appnd_start()
225 		return(-1);  in appnd_start()
233 	skcnt += bufend - bufpt;  in appnd_start()
237 		goto out;  in appnd_start()
241 	 * now in front of, read up the block and position the pointer after  in appnd_start()
244 	if ((cnt -= skcnt) > 0) {  in appnd_start()
246 		 * watch out for stupid tape drives. ar_rev() will set rdblksz  in appnd_start()
255 				goto out;  in appnd_start()
258 		if (ar_rev((off_t)(bufpt - buf)) < 0)  in appnd_start()
259 			goto out;  in appnd_start()
270 	rdcnt -= skcnt;  in appnd_start()
280 		return(-1);  in appnd_start()
284     out:  in appnd_start()
286 	return(-1);  in appnd_start()
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.
297  *	0 on success, and -1 on failure
307 	 * if the user says bail out on first fault, we are out of here...  in rd_sync()
310 		return(-1);  in rd_sync()
312 		paxwarn(1, "Unable to append when there are archive read errors.");  in rd_sync()
313 		return(-1);  in rd_sync()
321 			return(-1);  in rd_sync()
338 		 * Oh well, yet another failed read...  in rd_sync()
343 		 * can extract out of the archive.  in rd_sync()
346 			paxwarn(0,"Archive read error limit (%d) reached",maxflt);  in rd_sync()
354 	return(-1);  in rd_sync()
371 	bufpt -= cnt;  in pback()
378  *	skip forward in the archive during an archive read. Used to get quickly
381  *	0 if ok, -1 failure, and 1 when EOF on the archive volume was detected.
399 	res = MIN((bufend - bufpt), skcnt);  in rd_skip()
401 	skcnt -= res;  in rd_skip()
410 	 * We have to read more, calculate complete and partial record reads  in rd_skip()
418 	 * how much it can skip over. We will have to read the rest.  in rd_skip()
421 		return(-1);  in rd_skip()
422 	res += cnt - skipped;  in rd_skip()
426 	 * what is left we have to read (which may be the whole thing if  in rd_skip()
427 	 * ar_fow() told us the device can only read to skip records);  in rd_skip()
430 		cnt = bufend - bufpt;  in rd_skip()
432 		 * if the read fails, we will have to resync  in rd_skip()
435 			return(-1);  in rd_skip()
440 		res -= cnt;  in rd_skip()
447  *	flush out any data (and pad if required) the last block. We always pad
457 		memset(bufpt, 0, bufend - bufpt);  in wr_fin()
471  *	0 if buffer was filled ok, -1 o.w. (buffer flush failure)
475 wr_rdbuf(char *out, int outcnt)  in wr_rdbuf()  argument
484 		cnt = bufend - bufpt;  in wr_rdbuf()
486 			return(-1);  in wr_rdbuf()
491 		memcpy(bufpt, out, cnt);  in wr_rdbuf()
493 		out += cnt;  in wr_rdbuf()
494 		outcnt -= cnt;  in wr_rdbuf()
501  *	copy from the read buffer into a supplied buffer a specified number of
502  *	bytes. If the read buffer is empty fill it and continue to copy.
504  *	specific read routine.
507  *	-1 is a read error
521 		cnt = bufend - bufpt;  in rd_wrbuf()
524 			 * read error, return what we got (or the error if  in rd_wrbuf()
529 			if ((res = cpcnt - incnt) > 0)  in rd_wrbuf()
541 		incnt -= cnt;  in rd_wrbuf()
555  *	0 if ok, -1 if there was a buf_flush failure
567 		cnt = bufend - bufpt;  in wr_skip()
569 			return(-1);  in wr_skip()
573 		skcnt -= cnt;  in wr_skip()
592  *	0 ok, -1 if archive write failure. a short read of the file returns a
601 	off_t size = arcn->sb.st_size;  in wr_rdfile()
608 		cnt = bufend - bufpt;  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()
622 	 * or the file read failed.  in wr_rdfile()
625 		syswarn(1, errno, "Read fault on %s", arcn->org_name);  in wr_rdfile()
627 		paxwarn(1, "File changed size during read %s", arcn->org_name);  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()
643  *	was due to an archive read, we will catch that when we try to skip. If
653  *	0 ok, -1 if archive read failure. if we cannot write the entire file,
661 	off_t size = arcn->sb.st_size;  in rd_wrfile()
663 	char *fnm = arcn->name;  in rd_wrfile()
688 		cnt = bufend - bufpt;  in rd_wrfile()
690 		 * if we get a read error, we do not want to skip, as we may  in rd_wrfile()
707 			while (--cnt >= 0)  in rd_wrfile()
711 		size -= res;  in rd_wrfile()
720 	if (isem && (arcn->sb.st_size > 0L))  in rd_wrfile()
724 	 * if we failed from archive read, we do not want to skip  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()
740  *	copy the contents of one file to another. used during -rw phase of pax
751 	char *fnm = arcn->name;  in cp_file()
762 	 if (((off_t)(arcn->sb.st_blocks * BLKMULT)) >= arcn->sb.st_size)  in cp_file()
777 	 * read the source file and copy to destination file until EOF  in cp_file()
780 		if ((cnt = read(fd1, buf, blksz)) <= 0)  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()
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()
819  *	fill the read buffer with the next record (or what we can get) from
822  *	Number of bytes of data in the read buffer, -1 for read error, and
862 	return(-1);  in buf_fill()
871  *	0 if all is ok, -1 when a write error occurs.
883 	 * volume, prompt for the next volume. (The non-standard -R flag).  in buf_flush()
892 			return(-1);  in buf_flush()
898 		 * write blocksize. if so we figure out if we need to write  in buf_flush()
909 			push = bufcnt - blksz;  in buf_flush()
917 		 * write a block and check if it all went out ok  in buf_flush()
934 					push -= blksz;  in buf_flush()
950 			cnt = bufcnt - cnt;  in buf_flush()
953 			if (!frmt->blkalgn || ((cnt % frmt->blkalgn) == 0))  in buf_flush()
967 		 * size. if so, figure out if we have too much or too little  in buf_flush()
974 			push = bufcnt - blksz;  in buf_flush()
981 	return(-1);  in buf_flush()