xref: /netbsd-src/sbin/dump/traverse.c (revision 481fca6e59249d8ffcf24fef7cfbe7b131bfb080)
1 /*	$NetBSD: traverse.c,v 1.28 1999/10/01 04:35:23 perseant Exp $	*/
2 
3 /*-
4  * Copyright (c) 1980, 1988, 1991, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. All advertising materials mentioning features or use of this software
16  *    must display the following acknowledgement:
17  *	This product includes software developed by the University of
18  *	California, Berkeley and its contributors.
19  * 4. 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 #include <sys/cdefs.h>
37 #ifndef lint
38 #if 0
39 static char sccsid[] = "@(#)traverse.c	8.7 (Berkeley) 6/15/95";
40 #else
41 __RCSID("$NetBSD: traverse.c,v 1.28 1999/10/01 04:35:23 perseant Exp $");
42 #endif
43 #endif /* not lint */
44 
45 #include <sys/param.h>
46 #include <sys/time.h>
47 #include <sys/stat.h>
48 #ifdef sunos
49 #include <sys/vnode.h>
50 
51 #include <ufs/fs.h>
52 #include <ufs/fsdir.h>
53 #include <ufs/inode.h>
54 #else
55 #include <ufs/ufs/dir.h>
56 #include <ufs/ufs/dinode.h>
57 #include <ufs/ffs/fs.h>
58 #include <ufs/ffs/ffs_extern.h>
59 #endif
60 
61 #include <protocols/dumprestore.h>
62 
63 #include <ctype.h>
64 #include <errno.h>
65 #include <fts.h>
66 #include <stdio.h>
67 #ifdef __STDC__
68 #include <string.h>
69 #include <unistd.h>
70 #endif
71 
72 #include "dump.h"
73 
74 #define	HASDUMPEDFILE	0x1
75 #define	HASSUBDIRS	0x2
76 
77 #ifdef	FS_44INODEFMT
78 typedef	quad_t fsizeT;
79 #else
80 typedef	int32_t fsizeT;
81 #endif
82 
83 static	int dirindir __P((ino_t ino, daddr_t blkno, int level, long *size,
84     long *tapesize, int nodump));
85 static	void dmpindir __P((ino_t ino, daddr_t blk, int level, fsizeT *size));
86 static	int searchdir __P((ino_t ino, daddr_t blkno, long size, long filesize,
87     long *tapesize, int nodump));
88 
89 /*
90  * This is an estimation of the number of TP_BSIZE blocks in the file.
91  * It estimates the number of blocks in files with holes by assuming
92  * that all of the blocks accounted for by di_blocks are data blocks
93  * (when some of the blocks are usually used for indirect pointers);
94  * hence the estimate may be high.
95  */
96 long
97 blockest(dp)
98 	struct dinode *dp;
99 {
100 	long blkest, sizeest;
101 
102 	/*
103 	 * dp->di_size is the size of the file in bytes.
104 	 * dp->di_blocks stores the number of sectors actually in the file.
105 	 * If there are more sectors than the size would indicate, this just
106 	 *	means that there are indirect blocks in the file or unused
107 	 *	sectors in the last file block; we can safely ignore these
108 	 *	(blkest = sizeest below).
109 	 * If the file is bigger than the number of sectors would indicate,
110 	 *	then the file has holes in it.	In this case we must use the
111 	 *	block count to estimate the number of data blocks used, but
112 	 *	we use the actual size for estimating the number of indirect
113 	 *	dump blocks (sizeest vs. blkest in the indirect block
114 	 *	calculation).
115 	 */
116 	blkest = howmany(dbtob((u_int64_t)dp->di_blocks), TP_BSIZE);
117 	sizeest = howmany(dp->di_size, TP_BSIZE);
118 	if (blkest > sizeest)
119 		blkest = sizeest;
120 	if (dp->di_size > ufsib->ufs_bsize * NDADDR) {
121 		/* calculate the number of indirect blocks on the dump tape */
122 		blkest +=
123 			howmany(sizeest - NDADDR * ufsib->ufs_bsize / TP_BSIZE,
124 			TP_NINDIR);
125 	}
126 	return (blkest + 1);
127 }
128 
129 /* Auxiliary macro to pick up files changed since previous dump. */
130 #define	CHANGEDSINCE(dp, t) \
131 	((dp)->di_mtime >= (t) || (dp)->di_ctime >= (t))
132 
133 /* The WANTTODUMP macro decides whether a file should be dumped. */
134 #ifdef UF_NODUMP
135 #define	WANTTODUMP(dp) \
136 	(CHANGEDSINCE(dp, iswap32(spcl.c_ddate)) && \
137 	 (nonodump || ((dp)->di_flags & UF_NODUMP) != UF_NODUMP))
138 #else
139 #define	WANTTODUMP(dp) CHANGEDSINCE(dp, iswap32(spcl.c_ddate))
140 #endif
141 
142 /*
143  * Determine if given inode should be dumped
144  */
145 void
146 mapfileino(ino, tapesize, dirskipped)
147 	ino_t ino;
148 	long *tapesize;
149 	int *dirskipped;
150 {
151 	int mode;
152 	struct dinode *dp;
153 
154 	/*
155 	 * Skip inode if we've already marked it for dumping
156 	 */
157 	if (TSTINO(ino, usedinomap))
158 		return;
159 	dp = getino(ino);
160 	if ((mode = (dp->di_mode & IFMT)) == 0)
161 		return;
162 	/*
163 	 * Put all dirs in dumpdirmap, inodes that are to be dumped in the
164 	 * used map. All inode but dirs who have the nodump attribute go
165 	 * to the usedinomap.
166 	 */
167 	SETINO(ino, usedinomap);
168 	if (mode == IFDIR)
169 		SETINO(ino, dumpdirmap);
170 	if (WANTTODUMP(dp)) {
171 		SETINO(ino, dumpinomap);
172 		if (mode != IFREG && mode != IFDIR && mode != IFLNK)
173 			*tapesize += 1;
174 		else
175 			*tapesize += blockest(dp);
176 		return;
177 	}
178 	if (mode == IFDIR) {
179 #ifdef UF_NODUMP
180 		if (!nonodump && (dp->di_flags & UF_NODUMP))
181 			CLRINO(ino, usedinomap);
182 #endif
183 		*dirskipped = 1;
184 	}
185 }
186 
187 /*
188  * Dump pass 1.
189  *
190  * Walk the inode list for a filesystem to find all allocated inodes
191  * that have been modified since the previous dump time. Also, find all
192  * the directories in the filesystem.
193  */
194 int
195 mapfiles(maxino, tapesize, disk, dirv)
196 	ino_t maxino;
197 	long *tapesize;
198 	char *disk;
199 	char * const *dirv;
200 {
201 	int anydirskipped = 0;
202 
203 	if (dirv != NULL) {
204 		char	 curdir[MAXPATHLEN];
205 		FTS	*dirh;
206 		FTSENT	*entry;
207 		int	 d;
208 
209 		if (getcwd(curdir, sizeof(curdir)) == NULL) {
210 			msg("Can't determine cwd: %s\n", strerror(errno));
211 			dumpabort(0);
212 		}
213 		if ((dirh = fts_open(dirv, FTS_PHYSICAL|FTS_SEEDOT|FTS_XDEV,
214 		    		    NULL)) == NULL) {
215 			msg("fts_open failed: %s\n", strerror(errno));
216 			dumpabort(0);
217 		}
218 		while ((entry = fts_read(dirh)) != NULL) {
219 			switch (entry->fts_info) {
220 			case FTS_DNR:		/* an error */
221 			case FTS_ERR:
222 			case FTS_NS:
223 				msg("Can't fts_read %s: %s\n", entry->fts_path,
224 				    strerror(errno));
225 			case FTS_DP:		/* already seen dir */
226 				continue;
227 			}
228 			mapfileino(entry->fts_statp->st_ino, tapesize,
229 			    &anydirskipped);
230 		}
231 		(void)fts_close(dirh);
232 
233 		/*
234 		 * Add any parent directories
235 		 */
236 		for (d = 0 ; dirv[d] != NULL ; d++) {
237 			char path[MAXPATHLEN];
238 
239 			if (dirv[d][0] != '/')
240 				(void)snprintf(path, sizeof(path), "%s/%s",
241 				    curdir, dirv[d]);
242 			else
243 				(void)snprintf(path, sizeof(path), "%s",
244 				    dirv[d]);
245 			while (strcmp(path, disk) != 0) {
246 				char *p;
247 				struct stat sb;
248 
249 				if (*path == '\0')
250 					break;
251 				if ((p = strrchr(path, '/')) == NULL)
252 					break;
253 				if (p == path)
254 					break;
255 				*p = '\0';
256 				if (stat(path, &sb) == -1) {
257 					msg("Can't stat %s: %s\n", path,
258 					    strerror(errno));
259 					break;
260 				}
261 				mapfileino(sb.st_ino, tapesize, &anydirskipped);
262 			}
263 		}
264 
265 		/*
266 		 * Ensure that the root inode actually appears in the
267 		 * file list for a subdir
268 		 */
269 		mapfileino(ROOTINO, tapesize, &anydirskipped);
270 	} else {
271 		ino_t ino;
272 
273 		for (ino = ROOTINO; ino < maxino; ino++) {
274 			mapfileino(ino, tapesize, &anydirskipped);
275 		}
276 	}
277 	/*
278 	 * Restore gets very upset if the root is not dumped,
279 	 * so ensure that it always is dumped.
280 	 */
281 	SETINO(ROOTINO, dumpinomap);
282 	return (anydirskipped);
283 }
284 
285 /*
286  * Dump pass 2.
287  *
288  * Scan each directory on the filesystem to see if it has any modified
289  * files in it. If it does, and has not already been added to the dump
290  * list (because it was itself modified), then add it. If a directory
291  * has not been modified itself, contains no modified files and has no
292  * subdirectories, then it can be deleted from the dump list and from
293  * the list of directories. By deleting it from the list of directories,
294  * its parent may now qualify for the same treatment on this or a later
295  * pass using this algorithm.
296  */
297 int
298 mapdirs(maxino, tapesize)
299 	ino_t maxino;
300 	long *tapesize;
301 {
302 	struct  dinode *dp, di;
303 	int i, isdir, nodump;
304 	char *map;
305 	ino_t ino;
306 	long filesize;
307 	int ret, change = 0;
308 
309 	isdir = 0;		/* XXX just to get gcc to shut up */
310 	for (map = dumpdirmap, ino = 1; ino < maxino; ino++) {
311 		if (((ino - 1) % NBBY) == 0)	/* map is offset by 1 */
312 			isdir = *map++;
313 		else
314 			isdir >>= 1;
315 		/*
316 		 * If dir has been removed from the used map, it's either
317 		 * because it had the nodump flag, or it herited it from
318 		 * its parent. A directory can't be in dumpinomap if
319 		 * not in usedinomap, but we have to go throuh it anyway
320 		 * to propagate the nodump attribute.
321 		 */
322 		nodump = (TSTINO(ino, usedinomap) == 0);
323 		if ((isdir & 1) == 0 ||
324 		    (TSTINO(ino, dumpinomap) && nodump == 0))
325 			continue;
326 
327 		dp = getino(ino);
328 		di = *dp; /* inode buf may be changed in searchdir */
329 		filesize = di.di_size;
330 		for (ret = 0, i = 0; filesize > 0 && i < NDADDR; i++) {
331 			if (di.di_db[i] != 0)
332 				ret |= searchdir(ino, iswap32(di.di_db[i]),
333 					(long)ufs_dblksize(ufsib, &di, i),
334 					filesize, tapesize, nodump);
335 			if (ret & HASDUMPEDFILE)
336 				filesize = 0;
337 			else
338 				filesize -= ufsib->ufs_bsize;
339 		}
340 		for (i = 0; filesize > 0 && i < NIADDR; i++) {
341 			if (di.di_ib[i] == 0)
342 				continue;
343 			ret |= dirindir(ino, di.di_ib[i], i, &filesize,
344 			    tapesize, nodump);
345 		}
346 		if (ret & HASDUMPEDFILE) {
347 			SETINO(ino, dumpinomap);
348 			*tapesize += blockest(&di);
349 			change = 1;
350 			continue;
351 		}
352 		if (nodump) {
353 			if (ret & HASSUBDIRS)
354 				change = 1; /* subdirs have inherited nodump */
355 			CLRINO(ino, dumpdirmap);
356 		} else if ((ret & HASSUBDIRS) == 0) {
357 			if (!TSTINO(ino, dumpinomap)) {
358 				CLRINO(ino, dumpdirmap);
359 				change = 1;
360 			}
361 		}
362 	}
363 	return (change);
364 }
365 
366 /*
367  * Read indirect blocks, and pass the data blocks to be searched
368  * as directories. Quit as soon as any entry is found that will
369  * require the directory to be dumped.
370  */
371 static int
372 dirindir(ino, blkno, ind_level, filesize, tapesize, nodump)
373 	ino_t ino;
374 	daddr_t blkno;
375 	int ind_level;
376 	long *filesize;
377 	long *tapesize;
378 	int nodump;
379 {
380 	int ret = 0;
381 	int i;
382 	daddr_t	idblk[MAXNINDIR];
383 
384 	bread(fsatoda(ufsib, iswap32(blkno)), (char *)idblk,
385 		(int)ufsib->ufs_bsize);
386 	if (ind_level <= 0) {
387 		for (i = 0; *filesize > 0 && i < ufsib->ufs_nindir; i++) {
388 			blkno = idblk[i];
389 			if (blkno != 0)
390 				ret |= searchdir(ino, iswap32(blkno),
391 				    ufsib->ufs_bsize, *filesize,
392 				    tapesize, nodump);
393 			if (ret & HASDUMPEDFILE)
394 				*filesize = 0;
395 			else
396 				*filesize -= ufsib->ufs_bsize;
397 		}
398 		return (ret);
399 	}
400 	ind_level--;
401 	for (i = 0; *filesize > 0 && i < ufsib->ufs_nindir; i++) {
402 		blkno = idblk[i];
403 		if (blkno != 0)
404 			ret |= dirindir(ino, blkno, ind_level, filesize,
405 			    tapesize, nodump);
406 	}
407 	return (ret);
408 }
409 
410 /*
411  * Scan a disk block containing directory information looking to see if
412  * any of the entries are on the dump list and to see if the directory
413  * contains any subdirectories.
414  */
415 static int
416 searchdir(dino, blkno, size, filesize, tapesize, nodump)
417 	ino_t dino;
418 	daddr_t blkno;
419 	long size;
420 	long filesize;
421 	long *tapesize;
422 	int nodump;
423 {
424 	struct direct *dp;
425 	struct dinode *ip;
426 	long loc, ret = 0;
427 	char dblk[MAXBSIZE];
428 	ino_t ino;
429 
430 	bread(fsatoda(ufsib, blkno), dblk, (int)size);
431 	if (filesize < size)
432 		size = filesize;
433 	for (loc = 0; loc < size; ) {
434 		dp = (struct direct *)(dblk + loc);
435 		if (dp->d_reclen == 0) {
436 			msg("corrupted directory, inumber %d\n", dino);
437 			break;
438 		}
439 		loc += iswap16(dp->d_reclen);
440 		if (dp->d_ino == 0)
441 			continue;
442 		if (dp->d_name[0] == '.') {
443 			if (dp->d_name[1] == '\0')
444 				continue;
445 			if (dp->d_name[1] == '.' && dp->d_name[2] == '\0')
446 				continue;
447 		}
448 		ino = iswap32(dp->d_ino);
449 		if (nodump) {
450 			ip = getino(ino);
451 			if (TSTINO(ino, dumpinomap)) {
452 				CLRINO(ino, dumpinomap);
453 				CLRINO(ino, usedinomap);
454 				*tapesize -= blockest(ip);
455 			}
456 			/* Add dir back to the dir map, to propagate nodump */
457 			if ((ip->di_mode & IFMT) == IFDIR) {
458 				SETINO(ino, dumpdirmap);
459 				ret |= HASSUBDIRS;
460 			}
461 		} else {
462 			if (TSTINO(ino, dumpinomap)) {
463 				ret |= HASDUMPEDFILE;
464 				if (ret & HASSUBDIRS)
465 					break;
466 			}
467 			if (TSTINO(ino, dumpdirmap)) {
468 				ret |= HASSUBDIRS;
469 				if (ret & HASDUMPEDFILE)
470 					break;
471 			}
472 		}
473 	}
474 	return (ret);
475 }
476 
477 /*
478  * Dump passes 3 and 4.
479  *
480  * Dump the contents of an inode to tape.
481  */
482 void
483 dumpino(dp, ino)
484 	struct dinode *dp;
485 	ino_t ino;
486 {
487 	int ind_level, cnt;
488 	fsizeT size;
489 	char buf[TP_BSIZE];
490 
491 	if (newtape) {
492 		newtape = 0;
493 		dumpmap(dumpinomap, TS_BITS, ino);
494 	}
495 	CLRINO(ino, dumpinomap);
496 	if (needswap)
497 		ffs_dinode_swap(dp, &spcl.c_dinode);
498 	else
499 		spcl.c_dinode = *dp;
500 	spcl.c_type = iswap32(TS_INODE);
501 	spcl.c_count = 0;
502 	switch (dp->di_mode & IFMT) {
503 
504 	case 0:
505 		/*
506 		 * Freed inode.
507 		 */
508 		return;
509 
510 	case IFLNK:
511 		/*
512 		 * Check for short symbolic link.
513 		 */
514 		if (dp->di_size > 0 &&
515 #ifdef FS_44INODEFMT
516 		    (dp->di_size < ufsib->ufs_maxsymlinklen ||
517 		     (ufsib->ufs_maxsymlinklen == 0 && dp->di_blocks == 0))) {
518 #else
519 		    dp->di_blocks == 0) {
520 #endif
521 			spcl.c_addr[0] = 1;
522 			spcl.c_count = iswap32(1);
523 			writeheader(ino);
524 			memmove(buf, dp->di_shortlink, (u_long)dp->di_size);
525 			buf[dp->di_size] = '\0';
526 			writerec(buf, 0);
527 			return;
528 		}
529 		/* fall through */
530 
531 	case IFDIR:
532 	case IFREG:
533 		if (dp->di_size > 0)
534 			break;
535 		/* fall through */
536 
537 	case IFIFO:
538 	case IFSOCK:
539 	case IFCHR:
540 	case IFBLK:
541 		writeheader(ino);
542 		return;
543 
544 	default:
545 		msg("Warning: undefined file type 0%o\n", dp->di_mode & IFMT);
546 		return;
547 	}
548 	if (dp->di_size > NDADDR * ufsib->ufs_bsize)
549 		cnt = NDADDR * ufsib->ufs_frag;
550 	else
551 		cnt = howmany(dp->di_size, ufsib->ufs_fsize);
552 	blksout(&dp->di_db[0], cnt, ino);
553 	if ((size = dp->di_size - NDADDR * ufsib->ufs_bsize) <= 0)
554 		return;
555 	for (ind_level = 0; ind_level < NIADDR; ind_level++) {
556 		dmpindir(ino, dp->di_ib[ind_level], ind_level, &size);
557 		if (size <= 0)
558 			return;
559 	}
560 }
561 
562 /*
563  * Read indirect blocks, and pass the data blocks to be dumped.
564  */
565 static void
566 dmpindir(ino, blk, ind_level, size)
567 	ino_t ino;
568 	daddr_t blk;
569 	int ind_level;
570 	fsizeT *size;
571 {
572 	int i, cnt;
573 	daddr_t idblk[MAXNINDIR];
574 
575 	if (blk != 0)
576 		bread(fsatoda(ufsib, iswap32(blk)), (char *)idblk,
577 			(int) ufsib->ufs_bsize);
578 	else
579 		memset(idblk, 0, (int)ufsib->ufs_bsize);
580 	if (ind_level <= 0) {
581 		if (*size < ufsib->ufs_nindir * ufsib->ufs_bsize)
582 			cnt = howmany(*size, ufsib->ufs_fsize);
583 		else
584 			cnt = ufsib->ufs_nindir * ufsib->ufs_frag;
585 		*size -= ufsib->ufs_nindir * ufsib->ufs_bsize;
586 		blksout(&idblk[0], cnt, ino);
587 		return;
588 	}
589 	ind_level--;
590 	for (i = 0; i < ufsib->ufs_nindir; i++) {
591 		dmpindir(ino, idblk[i], ind_level, size);
592 		if (*size <= 0)
593 			return;
594 	}
595 }
596 
597 /*
598  * Collect up the data into tape record sized buffers and output them.
599  */
600 void
601 blksout(blkp, frags, ino)
602 	daddr_t *blkp;
603 	int frags;
604 	ino_t ino;
605 {
606 	daddr_t *bp;
607 	int i, j, count, blks, tbperdb;
608 
609 	blks = howmany(frags * ufsib->ufs_fsize, TP_BSIZE);
610 	tbperdb = ufsib->ufs_bsize >> tp_bshift;
611 	for (i = 0; i < blks; i += TP_NINDIR) {
612 		if (i + TP_NINDIR > blks)
613 			count = blks;
614 		else
615 			count = i + TP_NINDIR;
616 		for (j = i; j < count; j++)
617 			if (blkp[j / tbperdb] != 0)
618 				spcl.c_addr[j - i] = 1;
619 			else
620 				spcl.c_addr[j - i] = 0;
621 		spcl.c_count = iswap32(count - i);
622 		writeheader(ino);
623 		bp = &blkp[i / tbperdb];
624 		for (j = i; j < count; j += tbperdb, bp++)
625 			if (*bp != 0) {
626 				if (j + tbperdb <= count)
627 					dumpblock(iswap32(*bp), (int)ufsib->ufs_bsize);
628 				else
629 					dumpblock(iswap32(*bp), (count - j) * TP_BSIZE);
630 			}
631 		spcl.c_type = iswap32(TS_ADDR);
632 	}
633 }
634 
635 /*
636  * Dump a map to the tape.
637  */
638 void
639 dumpmap(map, type, ino)
640 	char *map;
641 	int type;
642 	ino_t ino;
643 {
644 	int i;
645 	char *cp;
646 
647 	spcl.c_type = iswap32(type);
648 	spcl.c_count = iswap32(howmany(mapsize * sizeof(char), TP_BSIZE));
649 	writeheader(ino);
650 	for (i = 0, cp = map; i < iswap32(spcl.c_count); i++, cp += TP_BSIZE)
651 		writerec(cp, 0);
652 }
653 
654 /*
655  * Write a header record to the dump tape.
656  */
657 void
658 writeheader(ino)
659 	ino_t ino;
660 {
661 	int32_t sum, cnt, *lp;
662 
663 	spcl.c_inumber = iswap32(ino);
664 	spcl.c_magic = iswap32(NFS_MAGIC);
665 	spcl.c_checksum = 0;
666 	lp = (int32_t *)&spcl;
667 	sum = 0;
668 	cnt = sizeof(union u_spcl) / (4 * sizeof(int32_t));
669 	while (--cnt >= 0) {
670 		sum += iswap32(*lp++);
671 		sum += iswap32(*lp++);
672 		sum += iswap32(*lp++);
673 		sum += iswap32(*lp++);
674 	}
675 	spcl.c_checksum = iswap32(CHECKSUM - sum);
676 	writerec((char *)&spcl, 1);
677 }
678