1 /*
2 * Copyright (C) 1984-2023 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_PROCFS
24 #include <sys/statfs.h>
25 #if HAVE_LINUX_MAGIC_H
26 #include <linux/magic.h>
27 #endif
28 #endif
29
30 typedef POSITION BLOCKNUM;
31
32 public int ignore_eoi;
33
34 /*
35 * Pool of buffers holding the most recently used blocks of the input file.
36 * The buffer pool is kept as a doubly-linked circular list,
37 * in order from most- to least-recently used.
38 * The circular list is anchored by the file state "thisfile".
39 */
40 struct bufnode {
41 struct bufnode *next, *prev;
42 struct bufnode *hnext, *hprev;
43 };
44
45 #define LBUFSIZE 8192
46 struct buf {
47 struct bufnode node;
48 BLOCKNUM block;
49 unsigned int datasize;
50 unsigned char data[LBUFSIZE];
51 };
52 #define bufnode_buf(bn) ((struct buf *) bn)
53
54 /*
55 * The file state is maintained in a filestate structure.
56 * A pointer to the filestate is kept in the ifile structure.
57 */
58 #define BUFHASH_SIZE 1024
59 struct filestate {
60 struct bufnode buflist;
61 struct bufnode hashtbl[BUFHASH_SIZE];
62 int file;
63 int flags;
64 POSITION fpos;
65 int nbufs;
66 BLOCKNUM block;
67 unsigned int offset;
68 POSITION fsize;
69 };
70
71 #define ch_bufhead thisfile->buflist.next
72 #define ch_buftail thisfile->buflist.prev
73 #define ch_nbufs thisfile->nbufs
74 #define ch_block thisfile->block
75 #define ch_offset thisfile->offset
76 #define ch_fpos thisfile->fpos
77 #define ch_fsize thisfile->fsize
78 #define ch_flags thisfile->flags
79 #define ch_file thisfile->file
80
81 #define END_OF_CHAIN (&thisfile->buflist)
82 #define END_OF_HCHAIN(h) (&thisfile->hashtbl[h])
83 #define BUFHASH(blk) ((blk) & (BUFHASH_SIZE-1))
84
85 /*
86 * Macros to manipulate the list of buffers in thisfile->buflist.
87 */
88 #define FOR_BUFS(bn) \
89 for (bn = ch_bufhead; bn != END_OF_CHAIN; bn = bn->next)
90
91 #define BUF_RM(bn) \
92 (bn)->next->prev = (bn)->prev; \
93 (bn)->prev->next = (bn)->next;
94
95 #define BUF_INS_HEAD(bn) \
96 (bn)->next = ch_bufhead; \
97 (bn)->prev = END_OF_CHAIN; \
98 ch_bufhead->prev = (bn); \
99 ch_bufhead = (bn);
100
101 #define BUF_INS_TAIL(bn) \
102 (bn)->next = END_OF_CHAIN; \
103 (bn)->prev = ch_buftail; \
104 ch_buftail->next = (bn); \
105 ch_buftail = (bn);
106
107 /*
108 * Macros to manipulate the list of buffers in thisfile->hashtbl[n].
109 */
110 #define FOR_BUFS_IN_CHAIN(h,bn) \
111 for (bn = thisfile->hashtbl[h].hnext; \
112 bn != END_OF_HCHAIN(h); bn = bn->hnext)
113
114 #define BUF_HASH_RM(bn) \
115 (bn)->hnext->hprev = (bn)->hprev; \
116 (bn)->hprev->hnext = (bn)->hnext;
117
118 #define BUF_HASH_INS(bn,h) \
119 (bn)->hnext = thisfile->hashtbl[h].hnext; \
120 (bn)->hprev = END_OF_HCHAIN(h); \
121 thisfile->hashtbl[h].hnext->hprev = (bn); \
122 thisfile->hashtbl[h].hnext = (bn);
123
124 static struct filestate *thisfile;
125 static int ch_ungotchar = -1;
126 static int maxbufs = -1;
127
128 extern int autobuf;
129 extern int sigs;
130 extern int secure;
131 extern int screen_trashed;
132 extern int follow_mode;
133 extern int waiting_for_data;
134 extern constant char helpdata[];
135 extern constant int size_helpdata;
136 extern IFILE curr_ifile;
137 #if LOGFILE
138 extern int logfile;
139 extern char *namelogfile;
140 #endif
141
142 static int ch_addbuf();
143
144
145 /*
146 * Get the character pointed to by the read pointer.
147 */
ch_get(void)148 static int ch_get(void)
149 {
150 struct buf *bp;
151 struct bufnode *bn;
152 int n;
153 int read_again;
154 int h;
155 POSITION pos;
156 POSITION len;
157
158 if (thisfile == NULL)
159 return (EOI);
160
161 /*
162 * Quick check for the common case where
163 * the desired char is in the head buffer.
164 */
165 if (ch_bufhead != END_OF_CHAIN)
166 {
167 bp = bufnode_buf(ch_bufhead);
168 if (ch_block == bp->block && ch_offset < bp->datasize)
169 return bp->data[ch_offset];
170 }
171
172 /*
173 * Look for a buffer holding the desired block.
174 */
175 waiting_for_data = FALSE;
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 for (;;)
225 {
226 pos = (ch_block * LBUFSIZE) + bp->datasize;
227 if ((len = ch_length()) != NULL_POSITION && pos >= len)
228 /*
229 * At end of file.
230 */
231 return (EOI);
232
233 if (pos != ch_fpos)
234 {
235 /*
236 * Not at the correct position: must seek.
237 * If input is a pipe, we're in trouble (can't seek on a pipe).
238 * Some data has been lost: just return "?".
239 */
240 if (!(ch_flags & CH_CANSEEK))
241 return ('?');
242 if (lseek(ch_file, (off_t)pos, SEEK_SET) == BAD_LSEEK)
243 {
244 error("seek error", NULL_PARG);
245 clear_eol();
246 return (EOI);
247 }
248 ch_fpos = pos;
249 }
250
251 /*
252 * Read the block.
253 * If we read less than a full block, that's ok.
254 * We use partial block and pick up the rest next time.
255 */
256 if (ch_ungotchar != -1)
257 {
258 bp->data[bp->datasize] = ch_ungotchar;
259 n = 1;
260 ch_ungotchar = -1;
261 } else if (ch_flags & CH_HELPFILE)
262 {
263 bp->data[bp->datasize] = helpdata[ch_fpos];
264 n = 1;
265 } else
266 {
267 n = iread(ch_file, &bp->data[bp->datasize],
268 (unsigned int)(LBUFSIZE - bp->datasize));
269 }
270
271 read_again = FALSE;
272 if (n == READ_INTR)
273 {
274 ch_fsize = pos;
275 return (EOI);
276 }
277 if (n == READ_AGAIN)
278 {
279 read_again = TRUE;
280 n = 0;
281 }
282 if (n < 0)
283 {
284 #if MSDOS_COMPILER==WIN32C
285 if (errno != EPIPE)
286 #endif
287 {
288 error("read error", NULL_PARG);
289 clear_eol();
290 }
291 n = 0;
292 }
293
294 #if LOGFILE
295 /*
296 * If we have a log file, write the new data to it.
297 */
298 if (!secure && logfile >= 0 && n > 0)
299 write(logfile, (char *) &bp->data[bp->datasize], n);
300 #endif
301
302 ch_fpos += n;
303 bp->datasize += n;
304
305 if (n == 0)
306 {
307 /* Either end of file or no data available.
308 * read_again indicates the latter. */
309 if (!read_again)
310 ch_fsize = pos;
311 if (ignore_eoi || read_again)
312 {
313 /* Wait a while, then try again. */
314 if (!waiting_for_data)
315 {
316 PARG parg;
317 parg.p_string = wait_message();
318 ixerror("%s", &parg);
319 waiting_for_data = TRUE;
320 }
321 sleep_ms(50); /* Reduce system load */
322 }
323 if (ignore_eoi && follow_mode == FOLLOW_NAME && curr_ifile_changed())
324 {
325 /* screen_trashed=2 causes make_display to reopen the file. */
326 screen_trashed = 2;
327 return (EOI);
328 }
329 if (sigs)
330 return (EOI);
331 }
332
333 found:
334 if (ch_bufhead != bn)
335 {
336 /*
337 * Move the buffer to the head of the buffer chain.
338 * This orders the buffer chain, most- to least-recently used.
339 */
340 BUF_RM(bn);
341 BUF_INS_HEAD(bn);
342
343 /*
344 * Move to head of hash chain too.
345 */
346 BUF_HASH_RM(bn);
347 BUF_HASH_INS(bn, h);
348 }
349
350 if (ch_offset < bp->datasize)
351 break;
352 /*
353 * After all that, we still don't have enough data.
354 * Go back and try again.
355 */
356 }
357 return (bp->data[ch_offset]);
358 }
359
360 /*
361 * ch_ungetchar is a rather kludgy and limited way to push
362 * a single char onto an input file descriptor.
363 */
ch_ungetchar(int c)364 public void ch_ungetchar(int c)
365 {
366 if (c != -1 && ch_ungotchar != -1)
367 error("ch_ungetchar overrun", NULL_PARG);
368 ch_ungotchar = c;
369 }
370
371 #if LOGFILE
372 /*
373 * Close the logfile.
374 * If we haven't read all of standard input into it, do that now.
375 */
end_logfile(void)376 public void end_logfile(void)
377 {
378 static int tried = FALSE;
379
380 if (logfile < 0)
381 return;
382 if (!tried && ch_fsize == NULL_POSITION)
383 {
384 tried = TRUE;
385 ierror("Finishing logfile", NULL_PARG);
386 while (ch_forw_get() != EOI)
387 if (ABORT_SIGS())
388 break;
389 }
390 close(logfile);
391 logfile = -1;
392 free(namelogfile);
393 namelogfile = NULL;
394 }
395
396 /*
397 * Start a log file AFTER less has already been running.
398 * Invoked from the - command; see toggle_option().
399 * Write all the existing buffered data to the log file.
400 */
sync_logfile(void)401 public void sync_logfile(void)
402 {
403 struct buf *bp;
404 struct bufnode *bn;
405 int warned = FALSE;
406 BLOCKNUM block;
407 BLOCKNUM nblocks;
408
409 if (logfile < 0)
410 return;
411 nblocks = (ch_fpos + LBUFSIZE - 1) / LBUFSIZE;
412 for (block = 0; block < nblocks; block++)
413 {
414 int wrote = FALSE;
415 FOR_BUFS(bn)
416 {
417 bp = bufnode_buf(bn);
418 if (bp->block == block)
419 {
420 write(logfile, (char *) bp->data, bp->datasize);
421 wrote = TRUE;
422 break;
423 }
424 }
425 if (!wrote && !warned)
426 {
427 error("Warning: log file is incomplete",
428 NULL_PARG);
429 warned = TRUE;
430 }
431 }
432 }
433
434 #endif
435
436 /*
437 * Determine if a specific block is currently in one of the buffers.
438 */
buffered(BLOCKNUM block)439 static int buffered(BLOCKNUM block)
440 {
441 struct buf *bp;
442 struct bufnode *bn;
443 int h;
444
445 h = BUFHASH(block);
446 FOR_BUFS_IN_CHAIN(h, bn)
447 {
448 bp = bufnode_buf(bn);
449 if (bp->block == block)
450 return (TRUE);
451 }
452 return (FALSE);
453 }
454
455 /*
456 * Seek to a specified position in the file.
457 * Return 0 if successful, non-zero if can't seek there.
458 */
ch_seek(POSITION pos)459 public int ch_seek(POSITION pos)
460 {
461 BLOCKNUM new_block;
462 POSITION len;
463
464 if (thisfile == NULL)
465 return (0);
466
467 len = ch_length();
468 if (pos < ch_zero() || (len != NULL_POSITION && pos > len))
469 return (1);
470
471 new_block = pos / LBUFSIZE;
472 if (!(ch_flags & CH_CANSEEK) && pos != ch_fpos && !buffered(new_block))
473 {
474 if (ch_fpos > pos)
475 return (1);
476 while (ch_fpos < pos)
477 {
478 if (ch_forw_get() == EOI)
479 return (1);
480 if (ABORT_SIGS())
481 return (1);
482 }
483 return (0);
484 }
485 /*
486 * Set read pointer.
487 */
488 ch_block = new_block;
489 ch_offset = pos % LBUFSIZE;
490 return (0);
491 }
492
493 /*
494 * Seek to the end of the file.
495 */
ch_end_seek(void)496 public int ch_end_seek(void)
497 {
498 POSITION len;
499
500 if (thisfile == NULL)
501 return (0);
502
503 if (ch_flags & CH_CANSEEK)
504 ch_fsize = filesize(ch_file);
505
506 len = ch_length();
507 if (len != NULL_POSITION)
508 return (ch_seek(len));
509
510 /*
511 * Do it the slow way: read till end of data.
512 */
513 while (ch_forw_get() != EOI)
514 if (ABORT_SIGS())
515 return (1);
516 return (0);
517 }
518
519 /*
520 * Seek to the last position in the file that is currently buffered.
521 */
ch_end_buffer_seek(void)522 public int ch_end_buffer_seek(void)
523 {
524 struct buf *bp;
525 struct bufnode *bn;
526 POSITION buf_pos;
527 POSITION end_pos;
528
529 if (thisfile == NULL || (ch_flags & CH_CANSEEK))
530 return (ch_end_seek());
531
532 end_pos = 0;
533 FOR_BUFS(bn)
534 {
535 bp = bufnode_buf(bn);
536 buf_pos = (bp->block * LBUFSIZE) + bp->datasize;
537 if (buf_pos > end_pos)
538 end_pos = buf_pos;
539 }
540
541 return (ch_seek(end_pos));
542 }
543
544 /*
545 * Seek to the beginning of the file, or as close to it as we can get.
546 * We may not be able to seek there if input is a pipe and the
547 * beginning of the pipe is no longer buffered.
548 */
ch_beg_seek(void)549 public int ch_beg_seek(void)
550 {
551 struct bufnode *bn;
552 struct bufnode *firstbn;
553
554 /*
555 * Try a plain ch_seek first.
556 */
557 if (ch_seek(ch_zero()) == 0)
558 return (0);
559
560 /*
561 * Can't get to position 0.
562 * Look thru the buffers for the one closest to position 0.
563 */
564 firstbn = ch_bufhead;
565 if (firstbn == END_OF_CHAIN)
566 return (1);
567 FOR_BUFS(bn)
568 {
569 if (bufnode_buf(bn)->block < bufnode_buf(firstbn)->block)
570 firstbn = bn;
571 }
572 ch_block = bufnode_buf(firstbn)->block;
573 ch_offset = 0;
574 return (0);
575 }
576
577 /*
578 * Return the length of the file, if known.
579 */
ch_length(void)580 public POSITION ch_length(void)
581 {
582 if (thisfile == NULL)
583 return (NULL_POSITION);
584 if (ignore_eoi)
585 return (NULL_POSITION);
586 if (ch_flags & CH_HELPFILE)
587 return (size_helpdata);
588 if (ch_flags & CH_NODATA)
589 return (0);
590 return (ch_fsize);
591 }
592
593 /*
594 * Return the current position in the file.
595 */
ch_tell(void)596 public POSITION ch_tell(void)
597 {
598 if (thisfile == NULL)
599 return (NULL_POSITION);
600 return (ch_block * LBUFSIZE) + ch_offset;
601 }
602
603 /*
604 * Get the current char and post-increment the read pointer.
605 */
ch_forw_get(void)606 public int ch_forw_get(void)
607 {
608 int c;
609
610 if (thisfile == NULL)
611 return (EOI);
612 c = ch_get();
613 if (c == EOI)
614 return (EOI);
615 if (ch_offset < LBUFSIZE-1)
616 ch_offset++;
617 else
618 {
619 ch_block ++;
620 ch_offset = 0;
621 }
622 return (c);
623 }
624
625 /*
626 * Pre-decrement the read pointer and get the new current char.
627 */
ch_back_get(void)628 public int ch_back_get(void)
629 {
630 if (thisfile == NULL)
631 return (EOI);
632 if (ch_offset > 0)
633 ch_offset --;
634 else
635 {
636 if (ch_block <= 0)
637 return (EOI);
638 if (!(ch_flags & CH_CANSEEK) && !buffered(ch_block-1))
639 return (EOI);
640 ch_block--;
641 ch_offset = LBUFSIZE-1;
642 }
643 return (ch_get());
644 }
645
646 /*
647 * Set max amount of buffer space.
648 * bufspace is in units of 1024 bytes. -1 mean no limit.
649 */
ch_setbufspace(int bufspace)650 public void ch_setbufspace(int bufspace)
651 {
652 if (bufspace < 0)
653 maxbufs = -1;
654 else
655 {
656 int lbufk = LBUFSIZE / 1024;
657 maxbufs = bufspace / lbufk + (bufspace % lbufk != 0);
658 if (maxbufs < 1)
659 maxbufs = 1;
660 }
661 }
662
663 /*
664 * Flush (discard) any saved file state, including buffer contents.
665 */
ch_flush(void)666 public void ch_flush(void)
667 {
668 struct bufnode *bn;
669
670 if (thisfile == NULL)
671 return;
672
673 if (!(ch_flags & CH_CANSEEK))
674 {
675 /*
676 * If input is a pipe, we don't flush buffer contents,
677 * since the contents can't be recovered.
678 */
679 ch_fsize = NULL_POSITION;
680 return;
681 }
682
683 /*
684 * Initialize all the buffers.
685 */
686 FOR_BUFS(bn)
687 {
688 bufnode_buf(bn)->block = -1;
689 }
690
691 /*
692 * Figure out the size of the file, if we can.
693 */
694 ch_fsize = filesize(ch_file);
695
696 /*
697 * Seek to a known position: the beginning of the file.
698 */
699 ch_fpos = 0;
700 ch_block = 0; /* ch_fpos / LBUFSIZE; */
701 ch_offset = 0; /* ch_fpos % LBUFSIZE; */
702
703 /*
704 * This is a kludge to workaround a Linux kernel bug: files in
705 * /proc have a size of 0 according to fstat() but have readable
706 * data. They are sometimes, but not always, seekable.
707 * Force them to be non-seekable here.
708 */
709 if (ch_fsize == 0)
710 {
711 ch_fsize = NULL_POSITION;
712 ch_flags &= ~CH_CANSEEK;
713 }
714
715 if (lseek(ch_file, (off_t)0, SEEK_SET) == BAD_LSEEK)
716 {
717 /*
718 * Warning only; even if the seek fails for some reason,
719 * there's a good chance we're at the beginning anyway.
720 * {{ I think this is bogus reasoning. }}
721 */
722 error("seek error to 0", NULL_PARG);
723 }
724 }
725
726 /*
727 * Allocate a new buffer.
728 * The buffer is added to the tail of the buffer chain.
729 */
ch_addbuf(void)730 static int ch_addbuf(void)
731 {
732 struct buf *bp;
733 struct bufnode *bn;
734
735 /*
736 * Allocate and initialize a new buffer and link it
737 * onto the tail of the buffer list.
738 */
739 bp = (struct buf *) calloc(1, sizeof(struct buf));
740 if (bp == NULL)
741 return (1);
742 ch_nbufs++;
743 bp->block = -1;
744 bn = &bp->node;
745
746 BUF_INS_TAIL(bn);
747 BUF_HASH_INS(bn, 0);
748 return (0);
749 }
750
751 /*
752 *
753 */
init_hashtbl(void)754 static void init_hashtbl(void)
755 {
756 int h;
757
758 for (h = 0; h < BUFHASH_SIZE; h++)
759 {
760 thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h);
761 thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h);
762 }
763 }
764
765 /*
766 * Delete all buffers for this file.
767 */
ch_delbufs(void)768 static void ch_delbufs(void)
769 {
770 struct bufnode *bn;
771
772 while (ch_bufhead != END_OF_CHAIN)
773 {
774 bn = ch_bufhead;
775 BUF_RM(bn);
776 free(bufnode_buf(bn));
777 }
778 ch_nbufs = 0;
779 init_hashtbl();
780 }
781
782 /*
783 * Is it possible to seek on a file descriptor?
784 */
seekable(int f)785 public int seekable(int f)
786 {
787 #if MSDOS_COMPILER
788 extern int fd0;
789 if (f == fd0 && !isatty(fd0))
790 {
791 /*
792 * In MS-DOS, pipes are seekable. Check for
793 * standard input, and pretend it is not seekable.
794 */
795 return (0);
796 }
797 #endif
798 return (lseek(f, (off_t)1, SEEK_SET) != BAD_LSEEK);
799 }
800
801 /*
802 * Force EOF to be at the current read position.
803 * This is used after an ignore_eof read, during which the EOF may change.
804 */
ch_set_eof(void)805 public void ch_set_eof(void)
806 {
807 if (ch_fsize != NULL_POSITION && ch_fsize < ch_fpos)
808 ch_fsize = ch_fpos;
809 }
810
811
812 /*
813 * Initialize file state for a new file.
814 */
ch_init(int f,int flags)815 public void ch_init(int f, int flags)
816 {
817 /*
818 * See if we already have a filestate for this file.
819 */
820 thisfile = (struct filestate *) get_filestate(curr_ifile);
821 if (thisfile == NULL)
822 {
823 /*
824 * Allocate and initialize a new filestate.
825 */
826 thisfile = (struct filestate *)
827 ecalloc(1, sizeof(struct filestate));
828 thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN;
829 thisfile->nbufs = 0;
830 thisfile->flags = flags;
831 thisfile->fpos = 0;
832 thisfile->block = 0;
833 thisfile->offset = 0;
834 thisfile->file = -1;
835 thisfile->fsize = NULL_POSITION;
836 init_hashtbl();
837 /*
838 * Try to seek; set CH_CANSEEK if it works.
839 */
840 if ((flags & CH_CANSEEK) && !seekable(f))
841 ch_flags &= ~CH_CANSEEK;
842 set_filestate(curr_ifile, (void *) thisfile);
843 }
844 if (thisfile->file == -1)
845 thisfile->file = f;
846 ch_flush();
847 }
848
849 /*
850 * Close a filestate.
851 */
ch_close(void)852 public void ch_close(void)
853 {
854 int keepstate = FALSE;
855
856 if (thisfile == NULL)
857 return;
858
859 if ((ch_flags & (CH_CANSEEK|CH_POPENED|CH_HELPFILE)) && !(ch_flags & CH_KEEPOPEN))
860 {
861 /*
862 * We can seek or re-open, so we don't need to keep buffers.
863 */
864 ch_delbufs();
865 } else
866 keepstate = TRUE;
867 if (!(ch_flags & CH_KEEPOPEN))
868 {
869 /*
870 * We don't need to keep the file descriptor open
871 * (because we can re-open it.)
872 * But don't really close it if it was opened via popen(),
873 * because pclose() wants to close it.
874 */
875 if (!(ch_flags & (CH_POPENED|CH_HELPFILE)))
876 close(ch_file);
877 ch_file = -1;
878 } else
879 keepstate = TRUE;
880 if (!keepstate)
881 {
882 /*
883 * We don't even need to keep the filestate structure.
884 */
885 free(thisfile);
886 thisfile = NULL;
887 set_filestate(curr_ifile, (void *) NULL);
888 }
889 }
890
891 /*
892 * Return ch_flags for the current file.
893 */
ch_getflags(void)894 public int ch_getflags(void)
895 {
896 if (thisfile == NULL)
897 return (0);
898 return (ch_flags);
899 }
900
901 #if 0
902 static void ch_dump(struct filestate *fs)
903 {
904 struct buf *bp;
905 struct bufnode *bn;
906 unsigned char *s;
907
908 if (fs == NULL)
909 {
910 printf(" --no filestate\n");
911 return;
912 }
913 printf(" file %d, flags %x, fpos %x, fsize %x, blk/off %x/%x\n",
914 fs->file, fs->flags, fs->fpos,
915 fs->fsize, fs->block, fs->offset);
916 printf(" %d bufs:\n", fs->nbufs);
917 for (bn = fs->next; bn != &fs->buflist; bn = bn->next)
918 {
919 bp = bufnode_buf(bn);
920 printf("%x: blk %x, size %x \"",
921 bp, bp->block, bp->datasize);
922 for (s = bp->data; s < bp->data + 30; s++)
923 if (*s >= ' ' && *s < 0x7F)
924 printf("%c", *s);
925 else
926 printf(".");
927 printf("\"\n");
928 }
929 }
930 #endif
931