1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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()
110 		return(-1);  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()
150 		return(-1);  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
209 		return(-1);  in appnd_start()
212 	 * if the user did not specify a write blocksize, inherit the size used  in appnd_start()
225 		return(-1);  in appnd_start()
233 	skcnt += bufend - bufpt;  in appnd_start()
240 	 * We may have gone too far if there is valid data in the block we are  in appnd_start()
242 	 * the valid data.  in appnd_start()
244 	if ((cnt -= skcnt) > 0) {  in appnd_start()
258 		if (ar_rev((off_t)(bufpt - buf)) < 0)  in appnd_start()
270 	rdcnt -= skcnt;  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()
280 		return(-1);  in appnd_start()
286 	return(-1);  in appnd_start()
297  *	0 on success, and -1 on failure
310 		return(-1);  in rd_sync()
313 		return(-1);  in rd_sync()
321 			return(-1);  in rd_sync()
329 			 * All right! got some data, fill that buffer  in rd_sync()
354 	return(-1);  in rd_sync()
359  *	push the data used during the archive id phase back into the I/O
371 	bufpt -= cnt;  in pback()
379  *	past file data and padding for files the user did NOT select.
381  *	0 if ok, -1 failure, and 1 when EOF on the archive volume was detected.
392 	 * consume what data we have in the buffer. If we have to move forward  in rd_skip()
394 	 * move within the archive without doing the expensive reads on data we  in rd_skip()
399 	res = MIN((bufend - bufpt), skcnt);  in rd_skip()
401 	skcnt -= res;  in rd_skip()
421 		return(-1);  in rd_skip()
422 	res += cnt - skipped;  in rd_skip()
430 		cnt = bufend - bufpt;  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()
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()
484 		cnt = bufend - bufpt;  in wr_rdbuf()
486 			return(-1);  in wr_rdbuf()
494 		outcnt -= cnt;  in wr_rdbuf()
507  *	-1 is a read error
521 		cnt = bufend - bufpt;  in rd_wrbuf()
525 			 * no data was copied). The caller must know that an  in rd_wrbuf()
529 			if ((res = cpcnt - incnt) > 0)  in rd_wrbuf()
535 		 * calculate how much data to copy based on what's left and  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
567 		cnt = bufend - bufpt;  in wr_skip()
569 			return(-1);  in wr_skip()
573 		skcnt -= cnt;  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
601 	off_t size = arcn->sb.st_size;  in wr_rdfile()
605 	 * while there are more bytes to write  in wr_rdfile()
608 		cnt = bufend - bufpt;  in wr_rdfile()
611 			return(-1);  in wr_rdfile()
616 		size -= res;  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()
640  *	extract the entire file (due to failure to write the file) we return
644  *	the format supplies a file data crc value, we calculate the actual crc
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,
661 	off_t size = arcn->sb.st_size;  in rd_wrfile()
663 	char *fnm = arcn->name;  in rd_wrfile()
671 	 * pass the blocksize of the file being written to the write routine,  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()
692 		 * error, we do want to skip over the unprocessed data.  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()
727 		return(-1);  in rd_wrfile()
730 	 * some formats record a crc on file data. If so, then we compare the  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
741  *	just as in rd_wrfile() we use a special write function to write the
751 	char *fnm = arcn->name;  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()
783 			res = write(fd2, buf, cnt);  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()
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
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.
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()
892 			return(-1);  in buf_flush()
898 		 * write blocksize. if so we figure out if we need to write  in buf_flush()
902 		 * CALLED). Push has the amount of "extra" data in the buffer  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()
927 				/* we have extra data to push to the front.  in buf_flush()
929 				 * so we loop back to write again  in buf_flush()
934 					push -= blksz;  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()
968 		 * data for using the new block size  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()