1/*
2 * Copyright (C) 1984-2012  Mark Nudelman
3 *
4 * You may distribute under the terms of either the GNU General Public
5 * License or the Less License, as specified in the README file.
6 *
7 * For more information, see the README file.
8 */
9
10
11/*
12 * Low level character input from the input file.
13 * We use these special purpose routines which optimize moving
14 * both forward and backward from the current read pointer.
15 */
16
17#include "less.h"
18#if MSDOS_COMPILER==WIN32C
19#include <errno.h>
20#include <windows.h>
21#endif
22
23#if HAVE_STAT_INO
24#include <sys/stat.h>
25extern dev_t curr_dev;
26extern ino_t curr_ino;
27#endif
28
29typedef POSITION BLOCKNUM;
30
31public int ignore_eoi;
32
33/*
34 * Pool of buffers holding the most recently used blocks of the input file.
35 * The buffer pool is kept as a doubly-linked circular list,
36 * in order from most- to least-recently used.
37 * The circular list is anchored by the file state "thisfile".
38 */
39struct bufnode {
40	struct bufnode *next, *prev;
41	struct bufnode *hnext, *hprev;
42};
43
44#define	LBUFSIZE	8192
45struct buf {
46	struct bufnode node;
47	BLOCKNUM block;
48	unsigned int datasize;
49	unsigned char data[LBUFSIZE];
50};
51#define bufnode_buf(bn)  ((struct buf *) bn)
52
53/*
54 * The file state is maintained in a filestate structure.
55 * A pointer to the filestate is kept in the ifile structure.
56 */
57#define	BUFHASH_SIZE	64
58struct filestate {
59	struct bufnode buflist;
60	struct bufnode hashtbl[BUFHASH_SIZE];
61	int file;
62	int flags;
63	POSITION fpos;
64	int nbufs;
65	BLOCKNUM block;
66	unsigned int offset;
67	POSITION fsize;
68};
69
70#define	ch_bufhead	thisfile->buflist.next
71#define	ch_buftail	thisfile->buflist.prev
72#define	ch_nbufs	thisfile->nbufs
73#define	ch_block	thisfile->block
74#define	ch_offset	thisfile->offset
75#define	ch_fpos		thisfile->fpos
76#define	ch_fsize	thisfile->fsize
77#define	ch_flags	thisfile->flags
78#define	ch_file		thisfile->file
79
80#define	END_OF_CHAIN	(&thisfile->buflist)
81#define	END_OF_HCHAIN(h) (&thisfile->hashtbl[h])
82#define BUFHASH(blk)	((blk) & (BUFHASH_SIZE-1))
83
84/*
85 * Macros to manipulate the list of buffers in thisfile->buflist.
86 */
87#define	FOR_BUFS(bn) \
88	for (bn = ch_bufhead;  bn != END_OF_CHAIN;  bn = bn->next)
89
90#define BUF_RM(bn) \
91	(bn)->next->prev = (bn)->prev; \
92	(bn)->prev->next = (bn)->next;
93
94#define BUF_INS_HEAD(bn) \
95	(bn)->next = ch_bufhead; \
96	(bn)->prev = END_OF_CHAIN; \
97	ch_bufhead->prev = (bn); \
98	ch_bufhead = (bn);
99
100#define BUF_INS_TAIL(bn) \
101	(bn)->next = END_OF_CHAIN; \
102	(bn)->prev = ch_buftail; \
103	ch_buftail->next = (bn); \
104	ch_buftail = (bn);
105
106/*
107 * Macros to manipulate the list of buffers in thisfile->hashtbl[n].
108 */
109#define	FOR_BUFS_IN_CHAIN(h,bn) \
110	for (bn = thisfile->hashtbl[h].hnext;  \
111	     bn != END_OF_HCHAIN(h);  bn = bn->hnext)
112
113#define	BUF_HASH_RM(bn) \
114	(bn)->hnext->hprev = (bn)->hprev; \
115	(bn)->hprev->hnext = (bn)->hnext;
116
117#define	BUF_HASH_INS(bn,h) \
118	(bn)->hnext = thisfile->hashtbl[h].hnext; \
119	(bn)->hprev = END_OF_HCHAIN(h); \
120	thisfile->hashtbl[h].hnext->hprev = (bn); \
121	thisfile->hashtbl[h].hnext = (bn);
122
123static struct filestate *thisfile;
124static int ch_ungotchar = -1;
125static int maxbufs = -1;
126
127extern int autobuf;
128extern int sigs;
129extern int secure;
130extern int screen_trashed;
131extern int follow_mode;
132extern constant char helpdata[];
133extern constant int size_helpdata;
134extern IFILE curr_ifile;
135#if LOGFILE
136extern int logfile;
137extern char *namelogfile;
138#endif
139
140static int ch_addbuf();
141
142
143/*
144 * Get the character pointed to by the read pointer.
145 */
146	int
147ch_get()
148{
149	register struct buf *bp;
150	register struct bufnode *bn;
151	register int n;
152	register int slept;
153	register int h;
154	POSITION pos;
155	POSITION len;
156
157	if (thisfile == NULL)
158		return (EOI);
159
160	/*
161	 * Quick check for the common case where
162	 * the desired char is in the head buffer.
163	 */
164	if (ch_bufhead != END_OF_CHAIN)
165	{
166		bp = bufnode_buf(ch_bufhead);
167		if (ch_block == bp->block && ch_offset < bp->datasize)
168			return bp->data[ch_offset];
169	}
170
171	slept = FALSE;
172
173	/*
174	 * Look for a buffer holding the desired block.
175	 */
176	h = BUFHASH(ch_block);
177	FOR_BUFS_IN_CHAIN(h, bn)
178	{
179		bp = bufnode_buf(bn);
180		if (bp->block == ch_block)
181		{
182			if (ch_offset >= bp->datasize)
183				/*
184				 * Need more data in this buffer.
185				 */
186				break;
187			goto found;
188		}
189	}
190	if (bn == END_OF_HCHAIN(h))
191	{
192		/*
193		 * Block is not in a buffer.
194		 * Take the least recently used buffer
195		 * and read the desired block into it.
196		 * If the LRU buffer has data in it,
197		 * then maybe allocate a new buffer.
198		 */
199		if (ch_buftail == END_OF_CHAIN ||
200			bufnode_buf(ch_buftail)->block != -1)
201		{
202			/*
203			 * There is no empty buffer to use.
204			 * Allocate a new buffer if:
205			 * 1. We can't seek on this file and -b is not in effect; or
206			 * 2. We haven't allocated the max buffers for this file yet.
207			 */
208			if ((autobuf && !(ch_flags & CH_CANSEEK)) ||
209				(maxbufs < 0 || ch_nbufs < maxbufs))
210				if (ch_addbuf())
211					/*
212					 * Allocation failed: turn off autobuf.
213					 */
214					autobuf = OPT_OFF;
215		}
216		bn = ch_buftail;
217		bp = bufnode_buf(bn);
218		BUF_HASH_RM(bn); /* Remove from old hash chain. */
219		bp->block = ch_block;
220		bp->datasize = 0;
221		BUF_HASH_INS(bn, h); /* Insert into new hash chain. */
222	}
223
224    read_more:
225	pos = (ch_block * LBUFSIZE) + bp->datasize;
226	if ((len = ch_length()) != NULL_POSITION && pos >= len)
227		/*
228		 * At end of file.
229		 */
230		return (EOI);
231
232	if (pos != ch_fpos)
233	{
234		/*
235		 * Not at the correct position: must seek.
236		 * If input is a pipe, we're in trouble (can't seek on a pipe).
237		 * Some data has been lost: just return "?".
238		 */
239		if (!(ch_flags & CH_CANSEEK))
240			return ('?');
241		if (lseek(ch_file, (off_t)pos, SEEK_SET) == BAD_LSEEK)
242		{
243 			error("seek error", NULL_PARG);
244			clear_eol();
245			return (EOI);
246 		}
247 		ch_fpos = pos;
248 	}
249
250	/*
251	 * Read the block.
252	 * If we read less than a full block, that's ok.
253	 * We use partial block and pick up the rest next time.
254	 */
255	if (ch_ungotchar != -1)
256	{
257		bp->data[bp->datasize] = ch_ungotchar;
258		n = 1;
259		ch_ungotchar = -1;
260	} else if (ch_flags & CH_HELPFILE)
261	{
262		bp->data[bp->datasize] = helpdata[ch_fpos];
263		n = 1;
264	} else
265	{
266		n = iread(ch_file, &bp->data[bp->datasize],
267			(unsigned int)(LBUFSIZE - bp->datasize));
268	}
269
270	if (n == READ_INTR)
271		return (EOI);
272	if (n < 0)
273	{
274#if MSDOS_COMPILER==WIN32C
275		if (errno != EPIPE)
276#endif
277		{
278			error("read error", NULL_PARG);
279			clear_eol();
280		}
281		n = 0;
282	}
283
284#if LOGFILE
285	/*
286	 * If we have a log file, write the new data to it.
287	 */
288	if (!secure && logfile >= 0 && n > 0)
289		write(logfile, (char *) &bp->data[bp->datasize], n);
290#endif
291
292	ch_fpos += n;
293	bp->datasize += n;
294
295	/*
296	 * If we have read to end of file, set ch_fsize to indicate
297	 * the position of the end of file.
298	 */
299	if (n == 0)
300	{
301		ch_fsize = pos;
302		if (ignore_eoi)
303		{
304			/*
305			 * We are ignoring EOF.
306			 * Wait a while, then try again.
307			 */
308			if (!slept)
309			{
310				PARG parg;
311				parg.p_string = wait_message();
312				ierror("%s", &parg);
313			}
314#if !MSDOS_COMPILER
315	 		sleep(1);
316#else
317#if MSDOS_COMPILER==WIN32C
318			Sleep(1000);
319#endif
320#endif
321			slept = TRUE;
322
323#if HAVE_STAT_INO
324			if (follow_mode == FOLLOW_NAME)
325			{
326				/* See whether the file's i-number has changed.
327				 * If so, force the file to be closed and
328				 * reopened. */
329				struct stat st;
330				int r = stat(get_filename(curr_ifile), &st);
331				if (r == 0 && (st.st_ino != curr_ino ||
332					st.st_dev != curr_dev))
333				{
334					/* screen_trashed=2 causes
335					 * make_display to reopen the file. */
336					screen_trashed = 2;
337					return (EOI);
338				}
339			}
340#endif
341		}
342		if (sigs)
343			return (EOI);
344	}
345
346    found:
347	if (ch_bufhead != bn)
348	{
349		/*
350		 * Move the buffer to the head of the buffer chain.
351		 * This orders the buffer chain, most- to least-recently used.
352		 */
353		BUF_RM(bn);
354		BUF_INS_HEAD(bn);
355
356		/*
357		 * Move to head of hash chain too.
358		 */
359		BUF_HASH_RM(bn);
360		BUF_HASH_INS(bn, h);
361	}
362
363	if (ch_offset >= bp->datasize)
364		/*
365		 * After all that, we still don't have enough data.
366		 * Go back and try again.
367		 */
368		goto read_more;
369
370	return (bp->data[ch_offset]);
371}
372
373/*
374 * ch_ungetchar is a rather kludgy and limited way to push
375 * a single char onto an input file descriptor.
376 */
377	public void
378ch_ungetchar(c)
379	int c;
380{
381	if (c != -1 && ch_ungotchar != -1)
382		error("ch_ungetchar overrun", NULL_PARG);
383	ch_ungotchar = c;
384}
385
386#if LOGFILE
387/*
388 * Close the logfile.
389 * If we haven't read all of standard input into it, do that now.
390 */
391	public void
392end_logfile()
393{
394	static int tried = FALSE;
395
396	if (logfile < 0)
397		return;
398	if (!tried && ch_fsize == NULL_POSITION)
399	{
400		tried = TRUE;
401		ierror("Finishing logfile", NULL_PARG);
402		while (ch_forw_get() != EOI)
403			if (ABORT_SIGS())
404				break;
405	}
406	close(logfile);
407	logfile = -1;
408	namelogfile = NULL;
409}
410
411/*
412 * Start a log file AFTER less has already been running.
413 * Invoked from the - command; see toggle_option().
414 * Write all the existing buffered data to the log file.
415 */
416	public void
417sync_logfile()
418{
419	register struct buf *bp;
420	register struct bufnode *bn;
421	int warned = FALSE;
422	BLOCKNUM block;
423	BLOCKNUM nblocks;
424
425	nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
426	for (block = 0;  block < nblocks;  block++)
427	{
428		int wrote = FALSE;
429		FOR_BUFS(bn)
430		{
431			bp = bufnode_buf(bn);
432			if (bp->block == block)
433			{
434				write(logfile, (char *) bp->data, bp->datasize);
435				wrote = TRUE;
436				break;
437			}
438		}
439		if (!wrote && !warned)
440		{
441			error("Warning: log file is incomplete",
442				NULL_PARG);
443			warned = TRUE;
444		}
445	}
446}
447
448#endif
449
450/*
451 * Determine if a specific block is currently in one of the buffers.
452 */
453	static int
454buffered(block)
455	BLOCKNUM block;
456{
457	register struct buf *bp;
458	register struct bufnode *bn;
459	register int h;
460
461	h = BUFHASH(block);
462	FOR_BUFS_IN_CHAIN(h, bn)
463	{
464		bp = bufnode_buf(bn);
465		if (bp->block == block)
466			return (TRUE);
467	}
468	return (FALSE);
469}
470
471/*
472 * Seek to a specified position in the file.
473 * Return 0 if successful, non-zero if can't seek there.
474 */
475	public int
476ch_seek(pos)
477	register POSITION pos;
478{
479	BLOCKNUM new_block;
480	POSITION len;
481
482	if (thisfile == NULL)
483		return (0);
484
485	len = ch_length();
486	if (pos < ch_zero() || (len != NULL_POSITION && pos > len))
487		return (1);
488
489	new_block = pos / LBUFSIZE;
490	if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block))
491	{
492		if (ch_fpos > pos)
493			return (1);
494		while (ch_fpos < pos)
495		{
496			if (ch_forw_get() == EOI)
497				return (1);
498			if (ABORT_SIGS())
499				return (1);
500		}
501		return (0);
502	}
503	/*
504	 * Set read pointer.
505	 */
506	ch_block = new_block;
507	ch_offset = pos % LBUFSIZE;
508	return (0);
509}
510
511/*
512 * Seek to the end of the file.
513 */
514	public int
515ch_end_seek()
516{
517	POSITION len;
518
519	if (thisfile == NULL)
520		return (0);
521
522	if (ch_flags & CH_CANSEEK)
523		ch_fsize = filesize(ch_file);
524
525	len = ch_length();
526	if (len != NULL_POSITION)
527		return (ch_seek(len));
528
529	/*
530	 * Do it the slow way: read till end of data.
531	 */
532	while (ch_forw_get() != EOI)
533		if (ABORT_SIGS())
534			return (1);
535	return (0);
536}
537
538/*
539 * Seek to the beginning of the file, or as close to it as we can get.
540 * We may not be able to seek there if input is a pipe and the
541 * beginning of the pipe is no longer buffered.
542 */
543	public int
544ch_beg_seek()
545{
546	register struct bufnode *bn;
547	register struct bufnode *firstbn;
548
549	/*
550	 * Try a plain ch_seek first.
551	 */
552	if (ch_seek(ch_zero()) == 0)
553		return (0);
554
555	/*
556	 * Can't get to position 0.
557	 * Look thru the buffers for the one closest to position 0.
558	 */
559	firstbn = ch_bufhead;
560	if (firstbn == END_OF_CHAIN)
561		return (1);
562	FOR_BUFS(bn)
563	{
564		if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block)
565			firstbn = bn;
566	}
567	ch_block = bufnode_buf(firstbn)->block;
568	ch_offset = 0;
569	return (0);
570}
571
572/*
573 * Return the length of the file, if known.
574 */
575	public POSITION
576ch_length()
577{
578	if (thisfile == NULL)
579		return (NULL_POSITION);
580	if (ignore_eoi)
581		return (NULL_POSITION);
582	if (ch_flags & CH_HELPFILE)
583		return (size_helpdata);
584	if (ch_flags & CH_NODATA)
585		return (0);
586	return (ch_fsize);
587}
588
589/*
590 * Return the current position in the file.
591 */
592	public POSITION
593ch_tell()
594{
595	if (thisfile == NULL)
596		return (NULL_POSITION);
597	return (ch_block * LBUFSIZE) + ch_offset;
598}
599
600/*
601 * Get the current char and post-increment the read pointer.
602 */
603	public int
604ch_forw_get()
605{
606	register int c;
607
608	if (thisfile == NULL)
609		return (EOI);
610	c = ch_get();
611	if (c == EOI)
612		return (EOI);
613	if (ch_offset < LBUFSIZE-1)
614		ch_offset++;
615	else
616	{
617		ch_block ++;
618		ch_offset = 0;
619	}
620	return (c);
621}
622
623/*
624 * Pre-decrement the read pointer and get the new current char.
625 */
626	public int
627ch_back_get()
628{
629	if (thisfile == NULL)
630		return (EOI);
631	if (ch_offset > 0)
632		ch_offset --;
633	else
634	{
635		if (ch_block <= 0)
636			return (EOI);
637		if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1))
638			return (EOI);
639		ch_block--;
640		ch_offset = LBUFSIZE-1;
641	}
642	return (ch_get());
643}
644
645/*
646 * Set max amount of buffer space.
647 * bufspace is in units of 1024 bytes.  -1 mean no limit.
648 */
649	public void
650ch_setbufspace(bufspace)
651	int bufspace;
652{
653	if (bufspace < 0)
654		maxbufs = -1;
655	else
656	{
657		maxbufs = ((bufspace * 1024) + LBUFSIZE-1) / LBUFSIZE;
658		if (maxbufs < 1)
659			maxbufs = 1;
660	}
661}
662
663/*
664 * Flush (discard) any saved file state, including buffer contents.
665 */
666	public void
667ch_flush()
668{
669	register struct bufnode *bn;
670
671	if (thisfile == NULL)
672		return;
673
674	if (!(ch_flags & CH_CANSEEK))
675	{
676		/*
677		 * If input is a pipe, we don't flush buffer contents,
678		 * since the contents can't be recovered.
679		 */
680		ch_fsize = NULL_POSITION;
681		return;
682	}
683
684	/*
685	 * Initialize all the buffers.
686	 */
687	FOR_BUFS(bn)
688	{
689		bufnode_buf(bn)->block = -1;
690	}
691
692	/*
693	 * Figure out the size of the file, if we can.
694	 */
695	ch_fsize = filesize(ch_file);
696
697	/*
698	 * Seek to a known position: the beginning of the file.
699	 */
700	ch_fpos = 0;
701	ch_block = 0; /* ch_fpos / LBUFSIZE; */
702	ch_offset = 0; /* ch_fpos % LBUFSIZE; */
703
704#if 1
705	/*
706	 * This is a kludge to workaround a Linux kernel bug: files in
707	 * /proc have a size of 0 according to fstat() but have readable
708	 * data.  They are sometimes, but not always, seekable.
709	 * Force them to be non-seekable here.
710	 */
711	if (ch_fsize == 0)
712	{
713		ch_fsize = NULL_POSITION;
714		ch_flags &= ~CH_CANSEEK;
715	}
716#endif
717
718	if (lseek(ch_file, (off_t)0, SEEK_SET) == BAD_LSEEK)
719	{
720		/*
721		 * Warning only; even if the seek fails for some reason,
722		 * there's a good chance we're at the beginning anyway.
723		 * {{ I think this is bogus reasoning. }}
724		 */
725		error("seek error to 0", NULL_PARG);
726	}
727}
728
729/*
730 * Allocate a new buffer.
731 * The buffer is added to the tail of the buffer chain.
732 */
733	static int
734ch_addbuf()
735{
736	register struct buf *bp;
737	register struct bufnode *bn;
738
739	/*
740	 * Allocate and initialize a new buffer and link it
741	 * onto the tail of the buffer list.
742	 */
743	bp = (struct buf *) calloc(1, sizeof(struct buf));
744	if (bp == NULL)
745		return (1);
746	ch_nbufs++;
747	bp->block = -1;
748	bn = &bp->node;
749
750	BUF_INS_TAIL(bn);
751	BUF_HASH_INS(bn, 0);
752	return (0);
753}
754
755/*
756 *
757 */
758	static void
759init_hashtbl()
760{
761	register int h;
762
763	for (h = 0;  h < BUFHASH_SIZE;  h++)
764	{
765		thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
766		thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);
767	}
768}
769
770/*
771 * Delete all buffers for this file.
772 */
773	static void
774ch_delbufs()
775{
776	register struct bufnode *bn;
777
778	while (ch_bufhead != END_OF_CHAIN)
779	{
780		bn = ch_bufhead;
781		BUF_RM(bn);
782		free(bufnode_buf(bn));
783	}
784	ch_nbufs = 0;
785	init_hashtbl();
786}
787
788/*
789 * Is it possible to seek on a file descriptor?
790 */
791	public int
792seekable(f)
793	int f;
794{
795#if MSDOS_COMPILER
796	extern int fd0;
797	if (f == fd0 && !isatty(fd0))
798	{
799		/*
800		 * In MS-DOS, pipes are seekable.  Check for
801		 * standard input, and pretend it is not seekable.
802		 */
803		return (0);
804	}
805#endif
806	return (lseek(f, (off_t)1, SEEK_SET) != BAD_LSEEK);
807}
808
809/*
810 * Force EOF to be at the current read position.
811 * This is used after an ignore_eof read, during which the EOF may change.
812 */
813	public void
814ch_set_eof()
815{
816	ch_fsize = ch_fpos;
817}
818
819
820/*
821 * Initialize file state for a new file.
822 */
823	public void
824ch_init(f, flags)
825	int f;
826	int flags;
827{
828	/*
829	 * See if we already have a filestate for this file.
830	 */
831	thisfile = (struct filestate *) get_filestate(curr_ifile);
832	if (thisfile == NULL)
833	{
834		/*
835		 * Allocate and initialize a new filestate.
836		 */
837		thisfile = (struct filestate *)
838				calloc(1, sizeof(struct filestate));
839		thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN;
840		thisfile->nbufs = 0;
841		thisfile->flags = 0;
842		thisfile->fpos = 0;
843		thisfile->block = 0;
844		thisfile->offset = 0;
845		thisfile->file = -1;
846		thisfile->fsize = NULL_POSITION;
847		ch_flags = flags;
848		init_hashtbl();
849		/*
850		 * Try to seek; set CH_CANSEEK if it works.
851		 */
852		if ((flags & CH_CANSEEK) && !seekable(f))
853			ch_flags &= ~CH_CANSEEK;
854		set_filestate(curr_ifile, (void *) thisfile);
855	}
856	if (thisfile->file == -1)
857		thisfile->file = f;
858	ch_flush();
859}
860
861/*
862 * Close a filestate.
863 */
864	public void
865ch_close()
866{
867	int keepstate = FALSE;
868
869	if (thisfile == NULL)
870		return;
871
872	if (ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE))
873	{
874		/*
875		 * We can seek or re-open, so we don't need to keep buffers.
876		 */
877		ch_delbufs();
878	} else
879		keepstate = TRUE;
880	if (!(ch_flags & CH_KEEPOPEN))
881	{
882		/*
883		 * We don't need to keep the file descriptor open
884		 * (because we can re-open it.)
885		 * But don't really close it if it was opened via popen(),
886		 * because pclose() wants to close it.
887		 */
888		if (!(ch_flags & (CH_POPENED|CH_HELPFILE)))
889			close(ch_file);
890		ch_file = -1;
891	} else
892		keepstate = TRUE;
893	if (!keepstate)
894	{
895		/*
896		 * We don't even need to keep the filestate structure.
897		 */
898		free(thisfile);
899		thisfile = NULL;
900		set_filestate(curr_ifile, (void *) NULL);
901	}
902}
903
904/*
905 * Return ch_flags for the current file.
906 */
907	public int
908ch_getflags()
909{
910	if (thisfile == NULL)
911		return (0);
912	return (ch_flags);
913}
914
915#if 0
916	public void
917ch_dump(struct filestate *fs)
918{
919	struct buf *bp;
920	struct bufnode *bn;
921	unsigned char *s;
922
923	if (fs == NULL)
924	{
925		printf(" --no filestate\n");
926		return;
927	}
928	printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n",
929		fs->file, fs->flags, fs->fpos,
930		fs->fsize, fs->block, fs->offset);
931	printf(" %d bufs:\n", fs->nbufs);
932	for (bn = fs->next; bn != &fs->buflist;  bn = bn->next)
933	{
934		bp = bufnode_buf(bn);
935		printf("%x: blk %x, size %x \"",
936			bp, bp->block, bp->datasize);
937		for (s = bp->data;  s < bp->data + 30;  s++)
938			if (*s >= ' ' && *s < 0x7F)
939				printf("%c", *s);
940			else
941				printf(".");
942		printf("\"\n");
943	}
944}
945#endif
946