Bug Summary

File:src/usr.bin/less/less/../ch.c
Warning:line 214, column 32
Access to field 'datasize' results in a dereference of an undefined pointer value (loaded from variable 'bp')

Annotated Source Code

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clang -cc1 -cc1 -triple amd64-unknown-openbsd7.0 -analyze -disable-free -disable-llvm-verifier -discard-value-names -main-file-name ch.c -analyzer-store=region -analyzer-opt-analyze-nested-blocks -analyzer-checker=core -analyzer-checker=apiModeling -analyzer-checker=unix -analyzer-checker=deadcode -analyzer-checker=security.insecureAPI.UncheckedReturn -analyzer-checker=security.insecureAPI.getpw -analyzer-checker=security.insecureAPI.gets -analyzer-checker=security.insecureAPI.mktemp -analyzer-checker=security.insecureAPI.mkstemp -analyzer-checker=security.insecureAPI.vfork -analyzer-checker=nullability.NullPassedToNonnull -analyzer-checker=nullability.NullReturnedFromNonnull -analyzer-output plist -w -setup-static-analyzer -mrelocation-model pic -pic-level 1 -pic-is-pie -mframe-pointer=all -relaxed-aliasing -fno-rounding-math -mconstructor-aliases -munwind-tables -target-cpu x86-64 -target-feature +retpoline-indirect-calls -target-feature +retpoline-indirect-branches -tune-cpu generic -debugger-tuning=gdb -fcoverage-compilation-dir=/usr/src/usr.bin/less/less/obj -resource-dir /usr/local/lib/clang/13.0.0 -I /usr/src/usr.bin/less/less/.. -D SYSDIR="/etc" -D HELPDIR="/usr/share/misc" -internal-isystem /usr/local/lib/clang/13.0.0/include -internal-externc-isystem /usr/include -O2 -fdebug-compilation-dir=/usr/src/usr.bin/less/less/obj -ferror-limit 19 -fwrapv -D_RET_PROTECTOR -ret-protector -fgnuc-version=4.2.1 -vectorize-loops -vectorize-slp -fno-builtin-malloc -fno-builtin-calloc -fno-builtin-realloc -fno-builtin-valloc -fno-builtin-free -fno-builtin-strdup -fno-builtin-strndup -analyzer-output=html -faddrsig -D__GCC_HAVE_DWARF2_CFI_ASM=1 -o /home/ben/Projects/vmm/scan-build/2022-01-12-194120-40624-1 -x c /usr/src/usr.bin/less/less/../ch.c
1/*
2 * Copyright (C) 1984-2012 Mark Nudelman
3 * Modified for use with illumos by Garrett D'Amore.
4 * Copyright 2014 Garrett D'Amore <garrett@damore.org>
5 *
6 * You may distribute under the terms of either the GNU General Public
7 * License or the Less License, as specified in the README file.
8 *
9 * For more information, see the README file.
10 */
11
12/*
13 * Low level character input from the input file.
14 * We use these special purpose routines which optimize moving
15 * both forward and backward from the current read pointer.
16 */
17
18#include <sys/stat.h>
19
20#include "less.h"
21
22extern dev_t curr_dev;
23extern ino_t curr_ino;
24extern int less_is_more;
25
26typedef off_t BLOCKNUM;
27
28int ignore_eoi;
29
30/*
31 * Pool of buffers holding the most recently used blocks of the input file.
32 * The buffer pool is kept as a doubly-linked circular list,
33 * in order from most- to least-recently used.
34 * The circular list is anchored by the file state "thisfile".
35 */
36struct bufnode {
37 struct bufnode *next, *prev;
38 struct bufnode *hnext, *hprev;
39};
40
41#define LBUFSIZE8192 8192
42struct buf {
43 struct bufnode node;
44 BLOCKNUM block;
45 unsigned int datasize;
46 unsigned char data[LBUFSIZE8192];
47};
48#define bufnode_buf(bn)((struct buf *)bn) ((struct buf *)bn)
49
50/*
51 * The file state is maintained in a filestate structure.
52 * A pointer to the filestate is kept in the ifile structure.
53 */
54#define BUFHASH_SIZE64 64
55struct filestate {
56 struct bufnode buflist;
57 struct bufnode hashtbl[BUFHASH_SIZE64];
58 int file;
59 int flags;
60 off_t fpos;
61 int nbufs;
62 BLOCKNUM block;
63 unsigned int offset;
64 off_t fsize;
65};
66
67#define ch_bufheadthisfile->buflist.next thisfile->buflist.next
68#define ch_buftailthisfile->buflist.prev thisfile->buflist.prev
69#define ch_nbufsthisfile->nbufs thisfile->nbufs
70#define ch_blockthisfile->block thisfile->block
71#define ch_offsetthisfile->offset thisfile->offset
72#define ch_fposthisfile->fpos thisfile->fpos
73#define ch_fsizethisfile->fsize thisfile->fsize
74#define ch_flagsthisfile->flags thisfile->flags
75#define ch_filethisfile->file thisfile->file
76
77#define END_OF_CHAIN(&thisfile->buflist) (&thisfile->buflist)
78#define END_OF_HCHAIN(h)(&thisfile->hashtbl[h]) (&thisfile->hashtbl[h])
79#define BUFHASH(blk)((blk) & (64 -1)) ((blk) & (BUFHASH_SIZE64-1))
80
81/*
82 * Macros to manipulate the list of buffers in thisfile->buflist.
83 */
84#define FOR_BUFS(bn)for ((bn) = thisfile->buflist.next; (bn) != (&thisfile
->buflist); (bn) = (bn)->next) \
85 for ((bn) = ch_bufheadthisfile->buflist.next; (bn) != END_OF_CHAIN(&thisfile->buflist); (bn) = (bn)->next)
86
87#define BUF_RM(bn)(bn)->next->prev = (bn)->prev; (bn)->prev->next
= (bn)->next; \
88 (bn)->next->prev = (bn)->prev; \
89 (bn)->prev->next = (bn)->next;
90
91#define BUF_INS_HEAD(bn)(bn)->next = thisfile->buflist.next; (bn)->prev = (&
thisfile->buflist); thisfile->buflist.next->prev = (
bn); thisfile->buflist.next = (bn); \
92 (bn)->next = ch_bufheadthisfile->buflist.next; \
93 (bn)->prev = END_OF_CHAIN(&thisfile->buflist); \
94 ch_bufheadthisfile->buflist.next->prev = (bn); \
95 ch_bufheadthisfile->buflist.next = (bn);
96
97#define BUF_INS_TAIL(bn)(bn)->next = (&thisfile->buflist); (bn)->prev = thisfile
->buflist.prev; thisfile->buflist.prev->next = (bn);
thisfile->buflist.prev = (bn); \
98 (bn)->next = END_OF_CHAIN(&thisfile->buflist); \
99 (bn)->prev = ch_buftailthisfile->buflist.prev; \
100 ch_buftailthisfile->buflist.prev->next = (bn); \
101 ch_buftailthisfile->buflist.prev = (bn);
102
103/*
104 * Macros to manipulate the list of buffers in thisfile->hashtbl[n].
105 */
106#define FOR_BUFS_IN_CHAIN(h, bn)for ((bn) = thisfile->hashtbl[h].hnext; (bn) != (&thisfile
->hashtbl[h]); (bn) = (bn)->hnext) \
107 for ((bn) = thisfile->hashtbl[h].hnext; \
108 (bn) != END_OF_HCHAIN(h)(&thisfile->hashtbl[h]); (bn) = (bn)->hnext)
109
110#define BUF_HASH_RM(bn)(bn)->hnext->hprev = (bn)->hprev; (bn)->hprev->
hnext = (bn)->hnext; \
111 (bn)->hnext->hprev = (bn)->hprev; \
112 (bn)->hprev->hnext = (bn)->hnext;
113
114#define BUF_HASH_INS(bn, h)(bn)->hnext = thisfile->hashtbl[h].hnext; (bn)->hprev
= (&thisfile->hashtbl[h]); thisfile->hashtbl[h].hnext
->hprev = (bn); thisfile->hashtbl[h].hnext = (bn); \
115 (bn)->hnext = thisfile->hashtbl[h].hnext; \
116 (bn)->hprev = END_OF_HCHAIN(h)(&thisfile->hashtbl[h]); \
117 thisfile->hashtbl[h].hnext->hprev = (bn); \
118 thisfile->hashtbl[h].hnext = (bn);
119
120static struct filestate *thisfile;
121static int ch_ungotchar = -1;
122static int maxbufs = -1;
123
124extern int autobuf;
125extern int secure;
126extern int screen_trashed;
127extern int follow_mode;
128extern IFILEvoid * curr_ifile;
129extern int logfile;
130extern char *namelogfile;
131
132static int ch_addbuf(void);
133
134
135/*
136 * Get the character pointed to by the read pointer.
137 */
138int
139ch_get(void)
140{
141 struct buf *bp;
6
←
'bp' declared without an initial value
→
142 struct bufnode *bn;
143 int n;
144 int slept;
145 int h;
146 off_t pos;
147 off_t len;
148
149 if (thisfile
6.1
'thisfile' is not equal to NULL
 == NULL((void *)0))
7
←
Taking false branch
→
150 return (EOI(-1));
151
152 /*
153 * Quick check for the common case where
154 * the desired char is in the head buffer.
155 */
156 if (ch_bufheadthisfile->buflist.next != END_OF_CHAIN(&thisfile->buflist)) {
8
←
Assuming the condition is false
→
9
←
Taking false branch
→
157 bp = bufnode_buf(ch_bufhead)((struct buf *)thisfile->buflist.next);
158 if (ch_blockthisfile->block == bp->block && ch_offsetthisfile->offset < bp->datasize)
159 return (bp->data[ch_offsetthisfile->offset]);
160 }
161
162 slept = FALSE0;
163
164 /*
165 * Look for a buffer holding the desired block.
166 */
167 h = BUFHASH(ch_block)((thisfile->block) & (64 -1));
168 FOR_BUFS_IN_CHAIN(h, bn)for ((bn) = thisfile->hashtbl[h].hnext; (bn) != (&thisfile
->hashtbl[h]); (bn) = (bn)->hnext) {
10
←
Loop condition is false. Execution continues on line 179
→
169 bp = bufnode_buf(bn)((struct buf *)bn);
170 if (bp->block == ch_blockthisfile->block) {
171 if (ch_offsetthisfile->offset >= bp->datasize)
172 /*
173 * Need more data in this buffer.
174 */
175 break;
176 goto found;
177 }
178 }
179 if (bn == END_OF_HCHAIN(h)(&thisfile->hashtbl[h])) {
11
←
Assuming the condition is false
→
12
←
Taking false branch
→
180 /*
181 * Block is not in a buffer.
182 * Take the least recently used buffer
183 * and read the desired block into it.
184 * If the LRU buffer has data in it,
185 * then maybe allocate a new buffer.
186 */
187 if (ch_buftailthisfile->buflist.prev == END_OF_CHAIN(&thisfile->buflist) ||
188 bufnode_buf(ch_buftail)((struct buf *)thisfile->buflist.prev)->block != -1) {
189 /*
190 * There is no empty buffer to use.
191 * Allocate a new buffer if:
192 * 1. We can't seek on this file and -b is not in
193 * effect; or
194 * 2. We haven't allocated the max buffers for this
195 * file yet.
196 */
197 if ((autobuf && !(ch_flagsthisfile->flags & CH_CANSEEK001)) ||
198 (maxbufs < 0 || ch_nbufsthisfile->nbufs < maxbufs))
199 if (ch_addbuf())
200 /*
201 * Allocation failed: turn off autobuf.
202 */
203 autobuf = OPT_OFF0;
204 }
205 bn = ch_buftailthisfile->buflist.prev;
206 bp = bufnode_buf(bn)((struct buf *)bn);
207 BUF_HASH_RM(bn)(bn)->hnext->hprev = (bn)->hprev; (bn)->hprev->
hnext = (bn)->hnext;; /* Remove from old hash chain. */
208 bp->block = ch_blockthisfile->block;
209 bp->datasize = 0;
210 BUF_HASH_INS(bn, h)(bn)->hnext = thisfile->hashtbl[h].hnext; (bn)->hprev
= (&thisfile->hashtbl[h]); thisfile->hashtbl[h].hnext
->hprev = (bn); thisfile->hashtbl[h].hnext = (bn);; /* Insert into new hash chain. */
211 }
212
213read_more:
214 pos = (ch_blockthisfile->block * LBUFSIZE8192) + bp->datasize;
13
←
Access to field 'datasize' results in a dereference of an undefined pointer value (loaded from variable 'bp')
215 if ((len = ch_length()) != -1 && pos >= len)
216 /*
217 * At end of file.
218 */
219 return (EOI(-1));
220
221 if (pos != ch_fposthisfile->fpos) {
222 /*
223 * Not at the correct position: must seek.
224 * If input is a pipe, we're in trouble (can't seek on a pipe).
225 * Some data has been lost: just return "?".
226 */
227 if (!(ch_flagsthisfile->flags & CH_CANSEEK001))
228 return ('?');
229 if (lseek(ch_filethisfile->file, (off_t)pos, SEEK_SET0) == (off_t)-1) {
230 error("seek error", NULL((void *)0));
231 clear_eol();
232 return (EOI(-1));
233 }
234 ch_fposthisfile->fpos = pos;
235 }
236
237 /*
238 * Read the block.
239 * If we read less than a full block, that's ok.
240 * We use partial block and pick up the rest next time.
241 */
242 if (ch_ungotchar != -1) {
243 bp->data[bp->datasize] = (unsigned char)ch_ungotchar;
244 n = 1;
245 ch_ungotchar = -1;
246 } else {
247 n = iread(ch_filethisfile->file, &bp->data[bp->datasize],
248 (unsigned int)(LBUFSIZE8192 - bp->datasize));
249 }
250
251 if (n == READ_INTR(-2))
252 return (EOI(-1));
253 if (n < 0) {
254 error("read error", NULL((void *)0));
255 clear_eol();
256 n = 0;
257 }
258
259 /*
260 * If we have a log file, write the new data to it.
261 */
262 if (!secure && logfile >= 0 && n > 0)
263 (void) write(logfile, (char *)&bp->data[bp->datasize], n);
264
265 ch_fposthisfile->fpos += n;
266 bp->datasize += n;
267
268 /*
269 * If we have read to end of file, set ch_fsize to indicate
270 * the position of the end of file.
271 */
272 if (n == 0) {
273 ch_fsizethisfile->fsize = pos;
274 if (ignore_eoi) {
275 /*
276 * We are ignoring EOF.
277 * Wait a while, then try again.
278 */
279 if (!slept) {
280 PARG parg;
281 parg.p_string = wait_message();
282 ierror("%s", &parg);
283 }
284 sleep(1);
285 slept = TRUE1;
286
287 if (follow_mode == FOLLOW_NAME1) {
288 /*
289 * See whether the file's i-number has changed.
290 * If so, force the file to be closed and
291 * reopened.
292 */
293 struct stat st;
294 int r = stat(get_filename(curr_ifile), &st);
295 if (r == 0 && (st.st_ino != curr_ino ||
296 st.st_dev != curr_dev)) {
297 /*
298 * screen_trashed=2 causes
299 * make_display to reopen the file.
300 */
301 screen_trashed = 2;
302 return (EOI(-1));
303 }
304 }
305 }
306 if (any_sigs())
307 return (EOI(-1));
308 }
309
310found:
311 if (ch_bufheadthisfile->buflist.next != bn) {
312 /*
313 * Move the buffer to the head of the buffer chain.
314 * This orders the buffer chain, most- to least-recently used.
315 */
316 BUF_RM(bn)(bn)->next->prev = (bn)->prev; (bn)->prev->next
= (bn)->next;;
317 BUF_INS_HEAD(bn)(bn)->next = thisfile->buflist.next; (bn)->prev = (&
thisfile->buflist); thisfile->buflist.next->prev = (
bn); thisfile->buflist.next = (bn);;
318
319 /*
320 * Move to head of hash chain too.
321 */
322 BUF_HASH_RM(bn)(bn)->hnext->hprev = (bn)->hprev; (bn)->hprev->
hnext = (bn)->hnext;;
323 BUF_HASH_INS(bn, h)(bn)->hnext = thisfile->hashtbl[h].hnext; (bn)->hprev
= (&thisfile->hashtbl[h]); thisfile->hashtbl[h].hnext
->hprev = (bn); thisfile->hashtbl[h].hnext = (bn);;
324 }
325
326 if (ch_offsetthisfile->offset >= bp->datasize)
327 /*
328 * After all that, we still don't have enough data.
329 * Go back and try again.
330 */
331 goto read_more;
332
333 return (bp->data[ch_offsetthisfile->offset]);
334}
335
336/*
337 * ch_ungetchar is a rather kludgy and limited way to push
338 * a single char onto an input file descriptor.
339 */
340void
341ch_ungetchar(int c)
342{
343 if (c != -1 && ch_ungotchar != -1)
344 error("ch_ungetchar overrun", NULL((void *)0));
345 ch_ungotchar = c;
346}
347
348/*
349 * Close the logfile.
350 * If we haven't read all of standard input into it, do that now.
351 */
352void
353end_logfile(void)
354{
355 static int tried = FALSE0;
356
357 if (logfile < 0)
358 return;
359 if (!tried && ch_fsizethisfile->fsize == -1) {
360 tried = TRUE1;
361 ierror("Finishing logfile", NULL((void *)0));
362 while (ch_forw_get() != EOI(-1))
363 if (abort_sigs())
364 break;
365 }
366 close(logfile);
367 logfile = -1;
368 free(namelogfile);
369 namelogfile = NULL((void *)0);
370}
371
372/*
373 * Start a log file AFTER less has already been running.
374 * Invoked from the - command; see toggle_option().
375 * Write all the existing buffered data to the log file.
376 */
377void
378sync_logfile(void)
379{
380 struct buf *bp;
381 struct bufnode *bn;
382 int warned = FALSE0;
383 BLOCKNUM block;
384 BLOCKNUM nblocks;
385
386 nblocks = (ch_fposthisfile->fpos + LBUFSIZE8192 - 1) / LBUFSIZE8192;
387 for (block = 0; block < nblocks; block++) {
388 int wrote = FALSE0;
389 FOR_BUFS(bn)for ((bn) = thisfile->buflist.next; (bn) != (&thisfile
->buflist); (bn) = (bn)->next) {
390 bp = bufnode_buf(bn)((struct buf *)bn);
391 if (bp->block == block) {
392 (void) write(logfile, (char *)bp->data,
393 bp->datasize);
394 wrote = TRUE1;
395 break;
396 }
397 }
398 if (!wrote && !warned) {
399 error("Warning: log file is incomplete", NULL((void *)0));
400 warned = TRUE1;
401 }
402 }
403}
404
405/*
406 * Determine if a specific block is currently in one of the buffers.
407 */
408static int
409buffered(BLOCKNUM block)
410{
411 struct buf *bp;
412 struct bufnode *bn;
413 int h;
414
415 h = BUFHASH(block)((block) & (64 -1));
416 FOR_BUFS_IN_CHAIN(h, bn)for ((bn) = thisfile->hashtbl[h].hnext; (bn) != (&thisfile
->hashtbl[h]); (bn) = (bn)->hnext) {
417 bp = bufnode_buf(bn)((struct buf *)bn);
418 if (bp->block == block)
419 return (TRUE1);
420 }
421 return (FALSE0);
422}
423
424/*
425 * Seek to a specified position in the file.
426 * Return 0 if successful, non-zero if can't seek there.
427 */
428int
429ch_seek(off_t pos)
430{
431 BLOCKNUM new_block;
432 off_t len;
433
434 if (thisfile == NULL((void *)0))
435 return (0);
436
437 len = ch_length();
438 if (pos < ch_zero()(0) || (len != -1 && pos > len))
439 return (1);
440
441 new_block = pos / LBUFSIZE8192;
442 if (!(ch_flagsthisfile->flags & CH_CANSEEK001) && pos != ch_fposthisfile->fpos &&
443 !buffered(new_block)) {
444 if (ch_fposthisfile->fpos > pos)
445 return (1);
446 while (ch_fposthisfile->fpos < pos) {
447 if (ch_forw_get() == EOI(-1))
448 return (1);
449 if (abort_sigs())
450 return (1);
451 }
452 return (0);
453 }
454 /*
455 * Set read pointer.
456 */
457 ch_blockthisfile->block = new_block;
458 ch_offsetthisfile->offset = pos % LBUFSIZE8192;
459 return (0);
460}
461
462/*
463 * Seek to the end of the file.
464 */
465int
466ch_end_seek(void)
467{
468 off_t len;
469
470 if (thisfile == NULL((void *)0))
471 return (0);
472
473 if (ch_flagsthisfile->flags & CH_CANSEEK001)
474 ch_fsizethisfile->fsize = filesize(ch_filethisfile->file);
475
476 len = ch_length();
477 if (len != -1)
478 return (ch_seek(len));
479
480 /*
481 * Do it the slow way: read till end of data.
482 */
483 while (ch_forw_get() != EOI(-1))
484 if (abort_sigs())
485 return (1);
486 return (0);
487}
488
489/*
490 * Seek to the beginning of the file, or as close to it as we can get.
491 * We may not be able to seek there if input is a pipe and the
492 * beginning of the pipe is no longer buffered.
493 */
494int
495ch_beg_seek(void)
496{
497 struct bufnode *bn;
498 struct bufnode *firstbn;
499
500 /*
501 * Try a plain ch_seek first.
502 */
503 if (ch_seek(ch_zero()(0)) == 0)
504 return (0);
505
506 /*
507 * Can't get to position 0.
508 * Look thru the buffers for the one closest to position 0.
509 */
510 firstbn = ch_bufheadthisfile->buflist.next;
511 if (firstbn == END_OF_CHAIN(&thisfile->buflist))
512 return (1);
513 FOR_BUFS(bn)for ((bn) = thisfile->buflist.next; (bn) != (&thisfile
->buflist); (bn) = (bn)->next) {
514 if (bufnode_buf(bn)((struct buf *)bn)->block < bufnode_buf(firstbn)((struct buf *)firstbn)->block)
515 firstbn = bn;
516 }
517 ch_blockthisfile->block = bufnode_buf(firstbn)((struct buf *)firstbn)->block;
518 ch_offsetthisfile->offset = 0;
519 return (0);
520}
521
522/*
523 * Return the length of the file, if known.
524 */
525off_t
526ch_length(void)
527{
528 if (thisfile == NULL((void *)0))
529 return (-1);
530 if (ignore_eoi)
531 return (-1);
532 if (ch_flagsthisfile->flags & CH_NODATA020)
533 return (0);
534 return (ch_fsizethisfile->fsize);
535}
536
537/*
538 * Return the current position in the file.
539 */
540off_t
541ch_tell(void)
542{
543 if (thisfile == NULL((void *)0))
544 return (-1);
545 return ((ch_blockthisfile->block * LBUFSIZE8192) + ch_offsetthisfile->offset);
546}
547
548/*
549 * Get the current char and post-increment the read pointer.
550 */
551int
552ch_forw_get(void)
553{
554 int c;
555
556 if (thisfile == NULL((void *)0))
557 return (EOI(-1));
558 c = ch_get();
559 if (c == EOI(-1))
560 return (EOI(-1));
561 if (ch_offsetthisfile->offset < LBUFSIZE8192-1) {
562 ch_offsetthisfile->offset++;
563 } else {
564 ch_blockthisfile->block ++;
565 ch_offsetthisfile->offset = 0;
566 }
567 return (c);
568}
569
570/*
571 * Pre-decrement the read pointer and get the new current char.
572 */
573int
574ch_back_get(void)
575{
576 if (thisfile == NULL((void *)0))
1
Assuming 'thisfile' is not equal to NULL
→
2
←
Taking false branch
→
577 return (EOI(-1));
578 if (ch_offsetthisfile->offset > 0) {
3
←
Assuming field 'offset' is > 0
→
4
←
Taking true branch
→
579 ch_offsetthisfile->offset --;
580 } else {
581 if (ch_blockthisfile->block <= 0)
582 return (EOI(-1));
583 if (!(ch_flagsthisfile->flags & CH_CANSEEK001) && !buffered(ch_blockthisfile->block-1))
584 return (EOI(-1));
585 ch_blockthisfile->block--;
586 ch_offsetthisfile->offset = LBUFSIZE8192-1;
587 }
588 return (ch_get());
5
←
Calling 'ch_get'
→
589}
590
591/*
592 * Set max amount of buffer space.
593 * bufspace is in units of 1024 bytes. -1 mean no limit.
594 */
595void
596ch_setbufspace(int bufspace)
597{
598 if (bufspace < 0) {
599 maxbufs = -1;
600 } else {
601 maxbufs = ((bufspace * 1024) + LBUFSIZE8192-1) / LBUFSIZE8192;
602 if (maxbufs < 1)
603 maxbufs = 1;
604 }
605}
606
607/*
608 * Flush (discard) any saved file state, including buffer contents.
609 */
610void
611ch_flush(void)
612{
613 struct bufnode *bn;
614
615 if (thisfile == NULL((void *)0))
616 return;
617
618 if (!(ch_flagsthisfile->flags & CH_CANSEEK001)) {
619 /*
620 * If input is a pipe, we don't flush buffer contents,
621 * since the contents can't be recovered.
622 */
623 ch_fsizethisfile->fsize = -1;
624 return;
625 }
626
627 /*
628 * Initialize all the buffers.
629 */
630 FOR_BUFS(bn)for ((bn) = thisfile->buflist.next; (bn) != (&thisfile
->buflist); (bn) = (bn)->next) {
631 bufnode_buf(bn)((struct buf *)bn)->block = -1;
632 }
633
634 /*
635 * Figure out the size of the file, if we can.
636 */
637 ch_fsizethisfile->fsize = filesize(ch_filethisfile->file);
638
639 /*
640 * Seek to a known position: the beginning of the file.
641 */
642 ch_fposthisfile->fpos = 0;
643 ch_blockthisfile->block = 0; /* ch_fpos / LBUFSIZE; */
644 ch_offsetthisfile->offset = 0; /* ch_fpos % LBUFSIZE; */
645
646 if (lseek(ch_filethisfile->file, (off_t)0, SEEK_SET0) == (off_t)-1) {
647 /*
648 * Warning only; even if the seek fails for some reason,
649 * there's a good chance we're at the beginning anyway.
650 * {{ I think this is bogus reasoning. }}
651 */
652 error("seek error to 0", NULL((void *)0));
653 }
654}
655
656/*
657 * Allocate a new buffer.
658 * The buffer is added to the tail of the buffer chain.
659 */
660static int
661ch_addbuf(void)
662{
663 struct buf *bp;
664 struct bufnode *bn;
665
666 /*
667 * Allocate and initialize a new buffer and link it
668 * onto the tail of the buffer list.
669 */
670 bp = calloc(1, sizeof (struct buf));
671 if (bp == NULL((void *)0))
672 return (1);
673 ch_nbufsthisfile->nbufs++;
674 bp->block = -1;
675 bn = &bp->node;
676
677 BUF_INS_TAIL(bn)(bn)->next = (&thisfile->buflist); (bn)->prev = thisfile
->buflist.prev; thisfile->buflist.prev->next = (bn);
thisfile->buflist.prev = (bn);;
678 BUF_HASH_INS(bn, 0)(bn)->hnext = thisfile->hashtbl[0].hnext; (bn)->hprev
= (&thisfile->hashtbl[0]); thisfile->hashtbl[0].hnext
->hprev = (bn); thisfile->hashtbl[0].hnext = (bn);;
679 return (0);
680}
681
682/*
683 *
684 */
685static void
686init_hashtbl(void)
687{
688 int h;
689
690 for (h = 0; h < BUFHASH_SIZE64; h++) {
691 thisfile->hashtbl[h].hnext = END_OF_HCHAIN(h)(&thisfile->hashtbl[h]);
692 thisfile->hashtbl[h].hprev = END_OF_HCHAIN(h)(&thisfile->hashtbl[h]);
693 }
694}
695
696/*
697 * Delete all buffers for this file.
698 */
699static void
700ch_delbufs(void)
701{
702 struct bufnode *bn;
703
704 while (ch_bufheadthisfile->buflist.next != END_OF_CHAIN(&thisfile->buflist)) {
705 bn = ch_bufheadthisfile->buflist.next;
706 BUF_RM(bn)(bn)->next->prev = (bn)->prev; (bn)->prev->next
= (bn)->next;;
707 free(bufnode_buf(bn)((struct buf *)bn));
708 }
709 ch_nbufsthisfile->nbufs = 0;
710 init_hashtbl();
711}
712
713/*
714 * Is it possible to seek on a file descriptor?
715 */
716int
717seekable(int f)
718{
719 return (lseek(f, (off_t)1, SEEK_SET0) != (off_t)-1);
720}
721
722/*
723 * Force EOF to be at the current read position.
724 * This is used after an ignore_eof read, during which the EOF may change.
725 */
726void
727ch_set_eof(void)
728{
729 ch_fsizethisfile->fsize = ch_fposthisfile->fpos;
730}
731
732
733/*
734 * Initialize file state for a new file.
735 */
736void
737ch_init(int f, int flags)
738{
739 /*
740 * See if we already have a filestate for this file.
741 */
742 thisfile = get_filestate(curr_ifile);
743 if (thisfile == NULL((void *)0)) {
744 /*
745 * Allocate and initialize a new filestate.
746 */
747 thisfile = calloc(1, sizeof (struct filestate));
748 thisfile->buflist.next = thisfile->buflist.prev = END_OF_CHAIN(&thisfile->buflist);
749 thisfile->nbufs = 0;
750 thisfile->flags = 0;
751 thisfile->fpos = 0;
752 thisfile->block = 0;
753 thisfile->offset = 0;
754 thisfile->file = -1;
755 thisfile->fsize = -1;
756 ch_flagsthisfile->flags = flags;
757 init_hashtbl();
758 /*
759 * Try to seek; set CH_CANSEEK if it works.
760 */
761 if ((flags & CH_CANSEEK001) && !seekable(f))
762 ch_flagsthisfile->flags &= ~CH_CANSEEK001;
763 set_filestate(curr_ifile, (void *) thisfile);
764 }
765 if (thisfile->file == -1)
766 thisfile->file = f;
767 ch_flush();
768}
769
770/*
771 * Close a filestate.
772 */
773void
774ch_close(void)
775{
776 int keepstate = FALSE0;
777
778 if (thisfile == NULL((void *)0))
779 return;
780
781 if (ch_flagsthisfile->flags & (CH_CANSEEK001|CH_POPENED004|CH_HELPFILE010)) {
782 /*
783 * We can seek or re-open, so we don't need to keep buffers.
784 */
785 ch_delbufs();
786 } else {
787 keepstate = TRUE1;
788 }
789 if (!(ch_flagsthisfile->flags & CH_KEEPOPEN002)) {
790 /*
791 * We don't need to keep the file descriptor open
792 * (because we can re-open it.)
793 * But don't really close it if it was opened via popen(),
794 * because pclose() wants to close it.
795 */
796 if (!(ch_flagsthisfile->flags & CH_POPENED004))
797 close(ch_filethisfile->file);
798 ch_filethisfile->file = -1;
799 } else {
800 keepstate = TRUE1;
801 }
802 if (!keepstate) {
803 /*
804 * We don't even need to keep the filestate structure.
805 */
806 free(thisfile);
807 thisfile = NULL((void *)0);
808 set_filestate(curr_ifile, NULL((void *)0));
809 }
810}
811
812/*
813 * Return ch_flags for the current file.
814 */
815int
816ch_getflags(void)
817{
818 if (thisfile == NULL((void *)0))
819 return (0);
820 return (ch_flagsthisfile->flags);
821}