FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_sbuf.c
1 /*-
2 * Copyright (c) 2000-2008 Poul-Henning Kamp
3 * Copyright (c) 2000-2008 Dag-Erling Coïdan Smørgrav
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer
11 * in this position and unchanged.
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 *
16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
26 * SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/11.0/sys/kern/subr_sbuf.c 288484 2015-10-02 09:23:14Z phk $");
31
32 #include <sys/param.h>
33
34 #ifdef _KERNEL
35 #include <sys/ctype.h>
36 #include <sys/errno.h>
37 #include <sys/kernel.h>
38 #include <sys/limits.h>
39 #include <sys/malloc.h>
40 #include <sys/systm.h>
41 #include <sys/uio.h>
42 #include <machine/stdarg.h>
43 #else /* _KERNEL */
44 #include <ctype.h>
45 #include <errno.h>
46 #include <limits.h>
47 #include <stdarg.h>
48 #include <stdio.h>
49 #include <stdlib.h>
50 #include <string.h>
51 #endif /* _KERNEL */
52
53 #include <sys/sbuf.h>
54
55 #ifdef _KERNEL
56 static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
57 #define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK|M_ZERO)
58 #define SBFREE(buf) free(buf, M_SBUF)
59 #else /* _KERNEL */
60 #define KASSERT(e, m)
61 #define SBMALLOC(size) calloc(1, size)
62 #define SBFREE(buf) free(buf)
63 #endif /* _KERNEL */
64
65 /*
66 * Predicates
67 */
68 #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC)
69 #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT)
70 #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED)
71 #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
72 #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
73 #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
74 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
75 #define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL)
76
77 /*
78 * Set / clear flags
79 */
80 #define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
81 #define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
82
83 #define SBUF_MINSIZE 2 /* Min is 1 byte + nulterm. */
84 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
85
86 #ifdef PAGE_SIZE
87 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
88 #define SBUF_MAXEXTENDINCR PAGE_SIZE
89 #else
90 #define SBUF_MAXEXTENDSIZE 4096
91 #define SBUF_MAXEXTENDINCR 4096
92 #endif
93
94 /*
95 * Debugging support
96 */
97 #if defined(_KERNEL) && defined(INVARIANTS)
98
99 static void
100 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
101 {
102
103 KASSERT(s != NULL,
104 ("%s called with a NULL sbuf pointer", fun));
105 KASSERT(s->s_buf != NULL,
106 ("%s called with uninitialized or corrupt sbuf", fun));
107 if (SBUF_ISFINISHED(s) && SBUF_NULINCLUDED(s)) {
108 KASSERT(s->s_len <= s->s_size,
109 ("wrote past end of sbuf (%jd >= %jd)",
110 (intmax_t)s->s_len, (intmax_t)s->s_size));
111 } else {
112 KASSERT(s->s_len < s->s_size,
113 ("wrote past end of sbuf (%jd >= %jd)",
114 (intmax_t)s->s_len, (intmax_t)s->s_size));
115 }
116 }
117
118 static void
119 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
120 {
121
122 KASSERT((s->s_flags & SBUF_FINISHED) == state,
123 ("%s called with %sfinished or corrupt sbuf", fun,
124 (state ? "un" : "")));
125 }
126
127 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
128 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
129
130 #else /* _KERNEL && INVARIANTS */
131
132 #define assert_sbuf_integrity(s) do { } while (0)
133 #define assert_sbuf_state(s, i) do { } while (0)
134
135 #endif /* _KERNEL && INVARIANTS */
136
137 #ifdef CTASSERT
138 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
139 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
140 #endif
141
142 static int
143 sbuf_extendsize(int size)
144 {
145 int newsize;
146
147 if (size < (int)SBUF_MAXEXTENDSIZE) {
148 newsize = SBUF_MINEXTENDSIZE;
149 while (newsize < size)
150 newsize *= 2;
151 } else {
152 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
153 }
154 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
155 return (newsize);
156 }
157
158 /*
159 * Extend an sbuf.
160 */
161 static int
162 sbuf_extend(struct sbuf *s, int addlen)
163 {
164 char *newbuf;
165 int newsize;
166
167 if (!SBUF_CANEXTEND(s))
168 return (-1);
169 newsize = sbuf_extendsize(s->s_size + addlen);
170 newbuf = SBMALLOC(newsize);
171 if (newbuf == NULL)
172 return (-1);
173 memcpy(newbuf, s->s_buf, s->s_size);
174 if (SBUF_ISDYNAMIC(s))
175 SBFREE(s->s_buf);
176 else
177 SBUF_SETFLAG(s, SBUF_DYNAMIC);
178 s->s_buf = newbuf;
179 s->s_size = newsize;
180 return (0);
181 }
182
183 /*
184 * Initialize the internals of an sbuf.
185 * If buf is non-NULL, it points to a static or already-allocated string
186 * big enough to hold at least length characters.
187 */
188 static struct sbuf *
189 sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags)
190 {
191
192 memset(s, 0, sizeof(*s));
193 s->s_flags = flags;
194 s->s_size = length;
195 s->s_buf = buf;
196
197 if ((s->s_flags & SBUF_AUTOEXTEND) == 0) {
198 KASSERT(s->s_size >= SBUF_MINSIZE,
199 ("attempt to create an sbuf smaller than %d bytes",
200 SBUF_MINSIZE));
201 }
202
203 if (s->s_buf != NULL)
204 return (s);
205
206 if ((flags & SBUF_AUTOEXTEND) != 0)
207 s->s_size = sbuf_extendsize(s->s_size);
208
209 s->s_buf = SBMALLOC(s->s_size);
210 if (s->s_buf == NULL)
211 return (NULL);
212 SBUF_SETFLAG(s, SBUF_DYNAMIC);
213 return (s);
214 }
215
216 /*
217 * Initialize an sbuf.
218 * If buf is non-NULL, it points to a static or already-allocated string
219 * big enough to hold at least length characters.
220 */
221 struct sbuf *
222 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
223 {
224
225 KASSERT(length >= 0,
226 ("attempt to create an sbuf of negative length (%d)", length));
227 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
228 ("%s called with invalid flags", __func__));
229
230 flags &= SBUF_USRFLAGMSK;
231 if (s != NULL)
232 return (sbuf_newbuf(s, buf, length, flags));
233
234 s = SBMALLOC(sizeof(*s));
235 if (s == NULL)
236 return (NULL);
237 if (sbuf_newbuf(s, buf, length, flags) == NULL) {
238 SBFREE(s);
239 return (NULL);
240 }
241 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
242 return (s);
243 }
244
245 #ifdef _KERNEL
246 /*
247 * Create an sbuf with uio data
248 */
249 struct sbuf *
250 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
251 {
252
253 KASSERT(uio != NULL,
254 ("%s called with NULL uio pointer", __func__));
255 KASSERT(error != NULL,
256 ("%s called with NULL error pointer", __func__));
257
258 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
259 if (s == NULL) {
260 *error = ENOMEM;
261 return (NULL);
262 }
263 *error = uiomove(s->s_buf, uio->uio_resid, uio);
264 if (*error != 0) {
265 sbuf_delete(s);
266 return (NULL);
267 }
268 s->s_len = s->s_size - 1;
269 if (SBUF_ISSECTION(s))
270 s->s_sect_len = s->s_size - 1;
271 *error = 0;
272 return (s);
273 }
274 #endif
275
276 int
277 sbuf_get_flags(struct sbuf *s)
278 {
279
280 return (s->s_flags & SBUF_USRFLAGMSK);
281 }
282
283 void
284 sbuf_clear_flags(struct sbuf *s, int flags)
285 {
286
287 s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
288 }
289
290 void
291 sbuf_set_flags(struct sbuf *s, int flags)
292 {
293
294
295 s->s_flags |= (flags & SBUF_USRFLAGMSK);
296 }
297
298 /*
299 * Clear an sbuf and reset its position.
300 */
301 void
302 sbuf_clear(struct sbuf *s)
303 {
304
305 assert_sbuf_integrity(s);
306 /* don't care if it's finished or not */
307
308 SBUF_CLEARFLAG(s, SBUF_FINISHED);
309 s->s_error = 0;
310 s->s_len = 0;
311 s->s_sect_len = 0;
312 }
313
314 /*
315 * Set the sbuf's end position to an arbitrary value.
316 * Effectively truncates the sbuf at the new position.
317 */
318 int
319 sbuf_setpos(struct sbuf *s, ssize_t pos)
320 {
321
322 assert_sbuf_integrity(s);
323 assert_sbuf_state(s, 0);
324
325 KASSERT(pos >= 0,
326 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
327 KASSERT(pos < s->s_size,
328 ("attempt to seek past end of sbuf (%jd >= %jd)",
329 (intmax_t)pos, (intmax_t)s->s_size));
330 KASSERT(!SBUF_ISSECTION(s),
331 ("attempt to seek when in a section"));
332
333 if (pos < 0 || pos > s->s_len)
334 return (-1);
335 s->s_len = pos;
336 return (0);
337 }
338
339 /*
340 * Set up a drain function and argument on an sbuf to flush data to
341 * when the sbuf buffer overflows.
342 */
343 void
344 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
345 {
346
347 assert_sbuf_state(s, 0);
348 assert_sbuf_integrity(s);
349 KASSERT(func == s->s_drain_func || s->s_len == 0,
350 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
351 s->s_drain_func = func;
352 s->s_drain_arg = ctx;
353 }
354
355 /*
356 * Call the drain and process the return.
357 */
358 static int
359 sbuf_drain(struct sbuf *s)
360 {
361 int len;
362
363 KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
364 KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
365 len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len);
366 if (len < 0) {
367 s->s_error = -len;
368 return (s->s_error);
369 }
370 KASSERT(len > 0 && len <= s->s_len,
371 ("Bad drain amount %d for sbuf %p", len, s));
372 s->s_len -= len;
373 /*
374 * Fast path for the expected case where all the data was
375 * drained.
376 */
377 if (s->s_len == 0)
378 return (0);
379 /*
380 * Move the remaining characters to the beginning of the
381 * string.
382 */
383 memmove(s->s_buf, s->s_buf + len, s->s_len);
384 return (0);
385 }
386
387 /*
388 * Append bytes to an sbuf. This is the core function for appending
389 * to an sbuf and is the main place that deals with extending the
390 * buffer and marking overflow.
391 */
392 static void
393 sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
394 {
395 size_t n;
396
397 assert_sbuf_integrity(s);
398 assert_sbuf_state(s, 0);
399
400 if (s->s_error != 0)
401 return;
402 while (len > 0) {
403 if (SBUF_FREESPACE(s) <= 0) {
404 /*
405 * If there is a drain, use it, otherwise extend the
406 * buffer.
407 */
408 if (s->s_drain_func != NULL)
409 (void)sbuf_drain(s);
410 else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
411 < 0)
412 s->s_error = ENOMEM;
413 if (s->s_error != 0)
414 return;
415 }
416 n = SBUF_FREESPACE(s);
417 if (len < n)
418 n = len;
419 memcpy(&s->s_buf[s->s_len], buf, n);
420 s->s_len += n;
421 if (SBUF_ISSECTION(s))
422 s->s_sect_len += n;
423 len -= n;
424 buf += n;
425 }
426 }
427
428 static void
429 sbuf_put_byte(struct sbuf *s, char c)
430 {
431
432 sbuf_put_bytes(s, &c, 1);
433 }
434
435 /*
436 * Append a byte string to an sbuf.
437 */
438 int
439 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
440 {
441
442 sbuf_put_bytes(s, buf, len);
443 if (s->s_error != 0)
444 return (-1);
445 return (0);
446 }
447
448 #ifdef _KERNEL
449 /*
450 * Copy a byte string from userland into an sbuf.
451 */
452 int
453 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
454 {
455
456 assert_sbuf_integrity(s);
457 assert_sbuf_state(s, 0);
458 KASSERT(s->s_drain_func == NULL,
459 ("Nonsensical copyin to sbuf %p with a drain", s));
460
461 if (s->s_error != 0)
462 return (-1);
463 if (len == 0)
464 return (0);
465 if (len > SBUF_FREESPACE(s)) {
466 sbuf_extend(s, len - SBUF_FREESPACE(s));
467 if (SBUF_FREESPACE(s) < len)
468 len = SBUF_FREESPACE(s);
469 }
470 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
471 return (-1);
472 s->s_len += len;
473
474 return (0);
475 }
476 #endif
477
478 /*
479 * Copy a byte string into an sbuf.
480 */
481 int
482 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
483 {
484
485 assert_sbuf_integrity(s);
486 assert_sbuf_state(s, 0);
487
488 sbuf_clear(s);
489 return (sbuf_bcat(s, buf, len));
490 }
491
492 /*
493 * Append a string to an sbuf.
494 */
495 int
496 sbuf_cat(struct sbuf *s, const char *str)
497 {
498 size_t n;
499
500 n = strlen(str);
501 sbuf_put_bytes(s, str, n);
502 if (s->s_error != 0)
503 return (-1);
504 return (0);
505 }
506
507 #ifdef _KERNEL
508 /*
509 * Append a string from userland to an sbuf.
510 */
511 int
512 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
513 {
514 size_t done;
515
516 assert_sbuf_integrity(s);
517 assert_sbuf_state(s, 0);
518 KASSERT(s->s_drain_func == NULL,
519 ("Nonsensical copyin to sbuf %p with a drain", s));
520
521 if (s->s_error != 0)
522 return (-1);
523
524 if (len == 0)
525 len = SBUF_FREESPACE(s); /* XXX return 0? */
526 if (len > SBUF_FREESPACE(s)) {
527 sbuf_extend(s, len);
528 if (SBUF_FREESPACE(s) < len)
529 len = SBUF_FREESPACE(s);
530 }
531 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
532 case ENAMETOOLONG:
533 s->s_error = ENOMEM;
534 /* fall through */
535 case 0:
536 s->s_len += done - 1;
537 if (SBUF_ISSECTION(s))
538 s->s_sect_len += done - 1;
539 break;
540 default:
541 return (-1); /* XXX */
542 }
543
544 return (done);
545 }
546 #endif
547
548 /*
549 * Copy a string into an sbuf.
550 */
551 int
552 sbuf_cpy(struct sbuf *s, const char *str)
553 {
554
555 assert_sbuf_integrity(s);
556 assert_sbuf_state(s, 0);
557
558 sbuf_clear(s);
559 return (sbuf_cat(s, str));
560 }
561
562 /*
563 * Format the given argument list and append the resulting string to an sbuf.
564 */
565 #ifdef _KERNEL
566
567 /*
568 * Append a non-NUL character to an sbuf. This prototype signature is
569 * suitable for use with kvprintf(9).
570 */
571 static void
572 sbuf_putc_func(int c, void *arg)
573 {
574
575 if (c != '\0')
576 sbuf_put_byte(arg, c);
577 }
578
579 int
580 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
581 {
582
583 assert_sbuf_integrity(s);
584 assert_sbuf_state(s, 0);
585
586 KASSERT(fmt != NULL,
587 ("%s called with a NULL format string", __func__));
588
589 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
590 if (s->s_error != 0)
591 return (-1);
592 return (0);
593 }
594 #else /* !_KERNEL */
595 int
596 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
597 {
598 va_list ap_copy;
599 int error, len;
600
601 assert_sbuf_integrity(s);
602 assert_sbuf_state(s, 0);
603
604 KASSERT(fmt != NULL,
605 ("%s called with a NULL format string", __func__));
606
607 if (s->s_error != 0)
608 return (-1);
609
610 /*
611 * For the moment, there is no way to get vsnprintf(3) to hand
612 * back a character at a time, to push everything into
613 * sbuf_putc_func() as was done for the kernel.
614 *
615 * In userspace, while drains are useful, there's generally
616 * not a problem attempting to malloc(3) on out of space. So
617 * expand a userland sbuf if there is not enough room for the
618 * data produced by sbuf_[v]printf(3).
619 */
620
621 error = 0;
622 do {
623 va_copy(ap_copy, ap);
624 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
625 fmt, ap_copy);
626 if (len < 0) {
627 s->s_error = errno;
628 return (-1);
629 }
630 va_end(ap_copy);
631
632 if (SBUF_FREESPACE(s) >= len)
633 break;
634 /* Cannot print with the current available space. */
635 if (s->s_drain_func != NULL && s->s_len > 0)
636 error = sbuf_drain(s);
637 else
638 error = sbuf_extend(s, len - SBUF_FREESPACE(s));
639 } while (error == 0);
640
641 /*
642 * s->s_len is the length of the string, without the terminating nul.
643 * When updating s->s_len, we must subtract 1 from the length that
644 * we passed into vsnprintf() because that length includes the
645 * terminating nul.
646 *
647 * vsnprintf() returns the amount that would have been copied,
648 * given sufficient space, so don't over-increment s_len.
649 */
650 if (SBUF_FREESPACE(s) < len)
651 len = SBUF_FREESPACE(s);
652 s->s_len += len;
653 if (SBUF_ISSECTION(s))
654 s->s_sect_len += len;
655 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
656 s->s_error = ENOMEM;
657
658 KASSERT(s->s_len < s->s_size,
659 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
660
661 if (s->s_error != 0)
662 return (-1);
663 return (0);
664 }
665 #endif /* _KERNEL */
666
667 /*
668 * Format the given arguments and append the resulting string to an sbuf.
669 */
670 int
671 sbuf_printf(struct sbuf *s, const char *fmt, ...)
672 {
673 va_list ap;
674 int result;
675
676 va_start(ap, fmt);
677 result = sbuf_vprintf(s, fmt, ap);
678 va_end(ap);
679 return (result);
680 }
681
682 /*
683 * Append a character to an sbuf.
684 */
685 int
686 sbuf_putc(struct sbuf *s, int c)
687 {
688
689 sbuf_put_byte(s, c);
690 if (s->s_error != 0)
691 return (-1);
692 return (0);
693 }
694
695 /*
696 * Trim whitespace characters from end of an sbuf.
697 */
698 int
699 sbuf_trim(struct sbuf *s)
700 {
701
702 assert_sbuf_integrity(s);
703 assert_sbuf_state(s, 0);
704 KASSERT(s->s_drain_func == NULL,
705 ("%s makes no sense on sbuf %p with drain", __func__, s));
706
707 if (s->s_error != 0)
708 return (-1);
709
710 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
711 --s->s_len;
712 if (SBUF_ISSECTION(s))
713 s->s_sect_len--;
714 }
715
716 return (0);
717 }
718
719 /*
720 * Check if an sbuf has an error.
721 */
722 int
723 sbuf_error(const struct sbuf *s)
724 {
725
726 return (s->s_error);
727 }
728
729 /*
730 * Finish off an sbuf.
731 */
732 int
733 sbuf_finish(struct sbuf *s)
734 {
735
736 assert_sbuf_integrity(s);
737 assert_sbuf_state(s, 0);
738
739 s->s_buf[s->s_len] = '\0';
740 if (SBUF_NULINCLUDED(s))
741 s->s_len++;
742 if (s->s_drain_func != NULL) {
743 while (s->s_len > 0 && s->s_error == 0)
744 s->s_error = sbuf_drain(s);
745 }
746 SBUF_SETFLAG(s, SBUF_FINISHED);
747 #ifdef _KERNEL
748 return (s->s_error);
749 #else
750 if (s->s_error != 0) {
751 errno = s->s_error;
752 return (-1);
753 }
754 return (0);
755 #endif
756 }
757
758 /*
759 * Return a pointer to the sbuf data.
760 */
761 char *
762 sbuf_data(struct sbuf *s)
763 {
764
765 assert_sbuf_integrity(s);
766 assert_sbuf_state(s, SBUF_FINISHED);
767 KASSERT(s->s_drain_func == NULL,
768 ("%s makes no sense on sbuf %p with drain", __func__, s));
769
770 return (s->s_buf);
771 }
772
773 /*
774 * Return the length of the sbuf data.
775 */
776 ssize_t
777 sbuf_len(struct sbuf *s)
778 {
779
780 assert_sbuf_integrity(s);
781 /* don't care if it's finished or not */
782 KASSERT(s->s_drain_func == NULL,
783 ("%s makes no sense on sbuf %p with drain", __func__, s));
784
785 if (s->s_error != 0)
786 return (-1);
787
788 /* If finished, nulterm is already in len, else add one. */
789 if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
790 return (s->s_len + 1);
791 return (s->s_len);
792 }
793
794 /*
795 * Clear an sbuf, free its buffer if necessary.
796 */
797 void
798 sbuf_delete(struct sbuf *s)
799 {
800 int isdyn;
801
802 assert_sbuf_integrity(s);
803 /* don't care if it's finished or not */
804
805 if (SBUF_ISDYNAMIC(s))
806 SBFREE(s->s_buf);
807 isdyn = SBUF_ISDYNSTRUCT(s);
808 memset(s, 0, sizeof(*s));
809 if (isdyn)
810 SBFREE(s);
811 }
812
813 /*
814 * Check if an sbuf has been finished.
815 */
816 int
817 sbuf_done(const struct sbuf *s)
818 {
819
820 return (SBUF_ISFINISHED(s));
821 }
822
823 /*
824 * Start a section.
825 */
826 void
827 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
828 {
829
830 assert_sbuf_integrity(s);
831 assert_sbuf_state(s, 0);
832
833 if (!SBUF_ISSECTION(s)) {
834 KASSERT(s->s_sect_len == 0,
835 ("s_sect_len != 0 when starting a section"));
836 if (old_lenp != NULL)
837 *old_lenp = -1;
838 SBUF_SETFLAG(s, SBUF_INSECTION);
839 } else {
840 KASSERT(old_lenp != NULL,
841 ("s_sect_len should be saved when starting a subsection"));
842 *old_lenp = s->s_sect_len;
843 s->s_sect_len = 0;
844 }
845 }
846
847 /*
848 * End the section padding to the specified length with the specified
849 * character.
850 */
851 ssize_t
852 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
853 {
854 ssize_t len;
855
856 assert_sbuf_integrity(s);
857 assert_sbuf_state(s, 0);
858 KASSERT(SBUF_ISSECTION(s),
859 ("attempt to end a section when not in a section"));
860
861 if (pad > 1) {
862 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
863 for (; s->s_error == 0 && len > 0; len--)
864 sbuf_put_byte(s, c);
865 }
866 len = s->s_sect_len;
867 if (old_len == -1) {
868 s->s_sect_len = 0;
869 SBUF_CLEARFLAG(s, SBUF_INSECTION);
870 } else {
871 s->s_sect_len += old_len;
872 }
873 if (s->s_error != 0)
874 return (-1);
875 return (len);
876 }
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