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 * $FreeBSD: head/sys/kern/subr_sbuf.c 255805 2013-09-22 23:47:56Z des $
29 */
30
31 #include <sys/param.h>
32 #include <sys/errno.h>
33
34 #ifdef _KERNEL
35 #include <sys/ctype.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/systm.h>
39 #include <sys/uio.h>
40 #include <machine/stdarg.h>
41 #else /* _KERNEL */
42 #include <ctype.h>
43 #include <stdarg.h>
44 #include <stdio.h>
45 #include <stdlib.h>
46 #include <string.h>
47 #endif /* _KERNEL */
48
49 #include <sys/sbuf.h>
50
51 #ifdef _KERNEL
52 static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
53 #define SBMALLOC(size) kmalloc(size, M_SBUF, M_WAITOK|M_ZERO)
54 #define SBFREE(buf) kfree(buf, M_SBUF)
55 #else /* _KERNEL */
56 #define KASSERT(e, m)
57 #define SBMALLOC(size) calloc(1, size)
58 #define SBFREE(buf) free(buf)
59 #define kvsnprintf vsnprintf
60 #endif /* _KERNEL */
61
62 /*
63 * Predicates
64 */
65 #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC)
66 #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT)
67 #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED)
68 #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
69 #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
70 #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
71 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
72
73 /*
74 * Set / clear flags
75 */
76 #define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
77 #define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
78
79 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
80
81 #ifdef PAGE_SIZE
82 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
83 #define SBUF_MAXEXTENDINCR PAGE_SIZE
84 #else
85 #define SBUF_MAXEXTENDSIZE 4096
86 #define SBUF_MAXEXTENDINCR 4096
87 #endif
88
89 /*
90 * Debugging support
91 */
92 #if defined(_KERNEL) && defined(INVARIANTS)
93
94 static void
_assert_sbuf_integrity(const char * fun,struct sbuf * s)95 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
96 {
97
98 KASSERT(s != NULL,
99 ("%s called with a NULL sbuf pointer", fun));
100 KASSERT(s->s_buf != NULL,
101 ("%s called with uninitialized or corrupt sbuf", fun));
102 KASSERT(s->s_len < s->s_size,
103 ("wrote past end of sbuf (%jd >= %jd)",
104 (intmax_t)s->s_len, (intmax_t)s->s_size));
105 }
106
107 static void
_assert_sbuf_state(const char * fun,struct sbuf * s,int state)108 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
109 {
110
111 KASSERT((s->s_flags & SBUF_FINISHED) == state,
112 ("%s called with %sfinished or corrupt sbuf", fun,
113 (state ? "un" : "")));
114 }
115
116 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
117 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
118
119 #else /* _KERNEL && INVARIANTS */
120
121 #define assert_sbuf_integrity(s) do { } while (0)
122 #define assert_sbuf_state(s, i) do { } while (0)
123
124 #endif /* _KERNEL && INVARIANTS */
125
126 #ifdef CTASSERT
127 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
128 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
129 #endif
130
131 static int
sbuf_extendsize(int size)132 sbuf_extendsize(int size)
133 {
134 int newsize;
135
136 if (size < (int)SBUF_MAXEXTENDSIZE) {
137 newsize = SBUF_MINEXTENDSIZE;
138 while (newsize < size)
139 newsize *= 2;
140 } else {
141 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
142 }
143 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
144 return (newsize);
145 }
146
147 /*
148 * Extend an sbuf.
149 */
150 static int
sbuf_extend(struct sbuf * s,int addlen)151 sbuf_extend(struct sbuf *s, int addlen)
152 {
153 char *newbuf;
154 int newsize;
155
156 if (!SBUF_CANEXTEND(s))
157 return (-1);
158 newsize = sbuf_extendsize(s->s_size + addlen);
159 newbuf = SBMALLOC(newsize);
160 if (newbuf == NULL)
161 return (-1);
162 memcpy(newbuf, s->s_buf, s->s_size);
163 if (SBUF_ISDYNAMIC(s))
164 SBFREE(s->s_buf);
165 else
166 SBUF_SETFLAG(s, SBUF_DYNAMIC);
167 s->s_buf = newbuf;
168 s->s_size = newsize;
169 return (0);
170 }
171
172 /*
173 * Initialize the internals of an sbuf.
174 * If buf is non-NULL, it points to a static or already-allocated string
175 * big enough to hold at least length characters.
176 */
177 static struct sbuf *
sbuf_newbuf(struct sbuf * s,char * buf,int length,int flags)178 sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags)
179 {
180
181 memset(s, 0, sizeof(*s));
182 s->s_flags = flags;
183 s->s_size = length;
184 s->s_buf = buf;
185
186 if ((s->s_flags & SBUF_AUTOEXTEND) == 0) {
187 KASSERT(s->s_size >= 0,
188 ("attempt to create a too small sbuf"));
189 }
190
191 if (s->s_buf != NULL)
192 return (s);
193
194 if ((flags & SBUF_AUTOEXTEND) != 0)
195 s->s_size = sbuf_extendsize(s->s_size);
196
197 s->s_buf = SBMALLOC(s->s_size);
198 if (s->s_buf == NULL)
199 return (NULL);
200 SBUF_SETFLAG(s, SBUF_DYNAMIC);
201 return (s);
202 }
203
204 /*
205 * Initialize an sbuf.
206 * If buf is non-NULL, it points to a static or already-allocated string
207 * big enough to hold at least length characters.
208 */
209 struct sbuf *
sbuf_new(struct sbuf * s,char * buf,int length,int flags)210 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
211 {
212
213 KASSERT(length >= 0,
214 ("attempt to create an sbuf of negative length (%d)", length));
215 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
216 ("%s called with invalid flags", __func__));
217
218 flags &= SBUF_USRFLAGMSK;
219 if (s != NULL)
220 return (sbuf_newbuf(s, buf, length, flags));
221
222 s = SBMALLOC(sizeof(*s));
223 if (s == NULL)
224 return (NULL);
225 if (sbuf_newbuf(s, buf, length, flags) == NULL) {
226 SBFREE(s);
227 return (NULL);
228 }
229 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
230 return (s);
231 }
232
233 #ifdef _KERNEL
234 /*
235 * Create an sbuf with uio data
236 */
237 struct sbuf *
sbuf_uionew(struct sbuf * s,struct uio * uio,int * error)238 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
239 {
240
241 KASSERT(uio != NULL,
242 ("%s called with NULL uio pointer", __func__));
243 KASSERT(error != NULL,
244 ("%s called with NULL error pointer", __func__));
245
246 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
247 if (s == NULL) {
248 *error = ENOMEM;
249 return (NULL);
250 }
251 *error = uiomove(s->s_buf, uio->uio_resid, uio);
252 if (*error != 0) {
253 sbuf_delete(s);
254 return (NULL);
255 }
256 s->s_len = s->s_size - 1;
257 if (SBUF_ISSECTION(s))
258 s->s_sect_len = s->s_size - 1;
259 *error = 0;
260 return (s);
261 }
262 #endif
263
264 /*
265 * Clear an sbuf and reset its position.
266 */
267 void
sbuf_clear(struct sbuf * s)268 sbuf_clear(struct sbuf *s)
269 {
270
271 assert_sbuf_integrity(s);
272 /* don't care if it's finished or not */
273
274 SBUF_CLEARFLAG(s, SBUF_FINISHED);
275 s->s_error = 0;
276 s->s_len = 0;
277 s->s_sect_len = 0;
278 }
279
280 /*
281 * Set the sbuf's end position to an arbitrary value.
282 * Effectively truncates the sbuf at the new position.
283 */
284 int
sbuf_setpos(struct sbuf * s,ssize_t pos)285 sbuf_setpos(struct sbuf *s, ssize_t pos)
286 {
287
288 assert_sbuf_integrity(s);
289 assert_sbuf_state(s, 0);
290
291 KASSERT(pos >= 0,
292 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
293 KASSERT(pos < s->s_size,
294 ("attempt to seek past end of sbuf (%jd >= %jd)",
295 (intmax_t)pos, (intmax_t)s->s_size));
296 KASSERT(!SBUF_ISSECTION(s),
297 ("attempt to seek when in a section"));
298
299 if (pos < 0 || pos > s->s_len)
300 return (-1);
301 s->s_len = pos;
302 return (0);
303 }
304
305 /*
306 * Set up a drain function and argument on an sbuf to flush data to
307 * when the sbuf buffer overflows.
308 */
309 void
sbuf_set_drain(struct sbuf * s,sbuf_drain_func * func,void * ctx)310 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
311 {
312
313 assert_sbuf_state(s, 0);
314 assert_sbuf_integrity(s);
315 KASSERT(func == s->s_drain_func || s->s_len == 0,
316 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
317 s->s_drain_func = func;
318 s->s_drain_arg = ctx;
319 }
320
321 /*
322 * Call the drain and process the return.
323 */
324 static int
sbuf_drain(struct sbuf * s)325 sbuf_drain(struct sbuf *s)
326 {
327 int len;
328
329 KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
330 KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
331 len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len);
332 if (len < 0) {
333 s->s_error = -len;
334 return (s->s_error);
335 }
336 KASSERT(len > 0 && len <= s->s_len,
337 ("Bad drain amount %d for sbuf %p", len, s));
338 s->s_len -= len;
339 /*
340 * Fast path for the expected case where all the data was
341 * drained.
342 */
343 if (s->s_len == 0)
344 return (0);
345 /*
346 * Move the remaining characters to the beginning of the
347 * string.
348 */
349 memmove(s->s_buf, s->s_buf + len, s->s_len);
350 return (0);
351 }
352
353 /*
354 * Append a byte to an sbuf. This is the core function for appending
355 * to an sbuf and is the main place that deals with extending the
356 * buffer and marking overflow.
357 */
358 static void
sbuf_put_byte(struct sbuf * s,int c)359 sbuf_put_byte(struct sbuf *s, int c)
360 {
361
362 assert_sbuf_integrity(s);
363 assert_sbuf_state(s, 0);
364
365 if (s->s_error != 0)
366 return;
367 if (SBUF_FREESPACE(s) <= 0) {
368 /*
369 * If there is a drain, use it, otherwise extend the
370 * buffer.
371 */
372 if (s->s_drain_func != NULL)
373 (void)sbuf_drain(s);
374 else if (sbuf_extend(s, 1) < 0)
375 s->s_error = ENOMEM;
376 if (s->s_error != 0)
377 return;
378 }
379 s->s_buf[s->s_len++] = c;
380 if (SBUF_ISSECTION(s))
381 s->s_sect_len++;
382 }
383
384 /*
385 * Append a byte string to an sbuf.
386 */
387 int
sbuf_bcat(struct sbuf * s,const void * buf,size_t len)388 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
389 {
390 const char *str = buf;
391 const char *end = str + len;
392
393 assert_sbuf_integrity(s);
394 assert_sbuf_state(s, 0);
395
396 if (s->s_error != 0)
397 return (-1);
398 for (; str < end; str++) {
399 sbuf_put_byte(s, *str);
400 if (s->s_error != 0)
401 return (-1);
402 }
403 return (0);
404 }
405
406 #ifdef _KERNEL
407 /*
408 * Copy a byte string from userland into an sbuf.
409 */
410 int
sbuf_bcopyin(struct sbuf * s,const void * uaddr,size_t len)411 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
412 {
413
414 assert_sbuf_integrity(s);
415 assert_sbuf_state(s, 0);
416 KASSERT(s->s_drain_func == NULL,
417 ("Nonsensical copyin to sbuf %p with a drain", s));
418
419 if (s->s_error != 0)
420 return (-1);
421 if (len == 0)
422 return (0);
423 if (len > SBUF_FREESPACE(s)) {
424 sbuf_extend(s, len - SBUF_FREESPACE(s));
425 if (SBUF_FREESPACE(s) < len)
426 len = SBUF_FREESPACE(s);
427 }
428 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
429 return (-1);
430 s->s_len += len;
431
432 return (0);
433 }
434 #endif
435
436 /*
437 * Copy a byte string into an sbuf.
438 */
439 int
sbuf_bcpy(struct sbuf * s,const void * buf,size_t len)440 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
441 {
442
443 assert_sbuf_integrity(s);
444 assert_sbuf_state(s, 0);
445
446 sbuf_clear(s);
447 return (sbuf_bcat(s, buf, len));
448 }
449
450 /*
451 * Append a string to an sbuf.
452 */
453 int
sbuf_cat(struct sbuf * s,const char * str)454 sbuf_cat(struct sbuf *s, const char *str)
455 {
456
457 assert_sbuf_integrity(s);
458 assert_sbuf_state(s, 0);
459
460 if (s->s_error != 0)
461 return (-1);
462
463 while (*str != '\0') {
464 sbuf_put_byte(s, *str++);
465 if (s->s_error != 0)
466 return (-1);
467 }
468 return (0);
469 }
470
471 #ifdef _KERNEL
472 /*
473 * Append a string from userland to an sbuf.
474 */
475 int
sbuf_copyin(struct sbuf * s,const void * uaddr,size_t len)476 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
477 {
478 size_t done;
479
480 assert_sbuf_integrity(s);
481 assert_sbuf_state(s, 0);
482 KASSERT(s->s_drain_func == NULL,
483 ("Nonsensical copyin to sbuf %p with a drain", s));
484
485 if (s->s_error != 0)
486 return (-1);
487
488 if (len == 0)
489 len = SBUF_FREESPACE(s); /* XXX return 0? */
490 if (len > SBUF_FREESPACE(s)) {
491 sbuf_extend(s, len);
492 if (SBUF_FREESPACE(s) < len)
493 len = SBUF_FREESPACE(s);
494 }
495 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
496 case ENAMETOOLONG:
497 s->s_error = ENOMEM;
498 /* fall through */
499 case 0:
500 s->s_len += done - 1;
501 if (SBUF_ISSECTION(s))
502 s->s_sect_len += done - 1;
503 break;
504 default:
505 return (-1); /* XXX */
506 }
507
508 return (done);
509 }
510 #endif
511
512 /*
513 * Copy a string into an sbuf.
514 */
515 int
sbuf_cpy(struct sbuf * s,const char * str)516 sbuf_cpy(struct sbuf *s, const char *str)
517 {
518
519 assert_sbuf_integrity(s);
520 assert_sbuf_state(s, 0);
521
522 sbuf_clear(s);
523 return (sbuf_cat(s, str));
524 }
525
526 /*
527 * Format the given argument list and append the resulting string to an sbuf.
528 */
529 #ifdef _KERNEL
530
531 /*
532 * Append a non-NUL character to an sbuf. This prototype signature is
533 * suitable for use with kvcprintf(9).
534 */
535 static void
sbuf_putc_func(int c,void * arg)536 sbuf_putc_func(int c, void *arg)
537 {
538
539 if (c != '\0')
540 sbuf_put_byte(arg, c);
541 }
542
543 int
sbuf_vprintf(struct sbuf * s,const char * fmt,__va_list ap)544 sbuf_vprintf(struct sbuf *s, const char *fmt, __va_list ap)
545 {
546
547 assert_sbuf_integrity(s);
548 assert_sbuf_state(s, 0);
549
550 KASSERT(fmt != NULL,
551 ("%s called with a NULL format string", __func__));
552
553 (void)kvcprintf(fmt, sbuf_putc_func, s, ap);
554 if (s->s_error != 0)
555 return (-1);
556 return (0);
557 }
558 #else /* !_KERNEL */
559 int
sbuf_vprintf(struct sbuf * s,const char * fmt,__va_list ap)560 sbuf_vprintf(struct sbuf *s, const char *fmt, __va_list ap)
561 {
562 __va_list ap_copy;
563 int error, len;
564
565 assert_sbuf_integrity(s);
566 assert_sbuf_state(s, 0);
567
568 KASSERT(fmt != NULL,
569 ("%s called with a NULL format string", __func__));
570
571 if (s->s_error != 0)
572 return (-1);
573
574 /*
575 * For the moment, there is no way to get vsnprintf(3) to hand
576 * back a character at a time, to push everything into
577 * sbuf_putc_func() as was done for the kernel.
578 *
579 * In userspace, while drains are useful, there's generally
580 * not a problem attempting to malloc(3) on out of space. So
581 * expand a userland sbuf if there is not enough room for the
582 * data produced by sbuf_[v]printf(3).
583 */
584
585 error = 0;
586 do {
587 va_copy(ap_copy, ap);
588 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
589 fmt, ap_copy);
590 __va_end(ap_copy);
591
592 if (SBUF_FREESPACE(s) >= len)
593 break;
594 /* Cannot print with the current available space. */
595 if (s->s_drain_func != NULL && s->s_len > 0)
596 error = sbuf_drain(s);
597 else
598 error = sbuf_extend(s, len - SBUF_FREESPACE(s));
599 } while (error == 0);
600
601 /*
602 * s->s_len is the length of the string, without the terminating nul.
603 * When updating s->s_len, we must subtract 1 from the length that
604 * we passed into vsnprintf() because that length includes the
605 * terminating nul.
606 *
607 * vsnprintf() returns the amount that would have been copied,
608 * given sufficient space, so don't over-increment s_len.
609 */
610 if (SBUF_FREESPACE(s) < len)
611 len = SBUF_FREESPACE(s);
612 s->s_len += len;
613 if (SBUF_ISSECTION(s))
614 s->s_sect_len += len;
615 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
616 s->s_error = ENOMEM;
617
618 KASSERT(s->s_len < s->s_size,
619 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
620
621 if (s->s_error != 0)
622 return (-1);
623 return (0);
624 }
625 #endif /* _KERNEL */
626
627 /*
628 * Format the given arguments and append the resulting string to an sbuf.
629 */
630 int
sbuf_printf(struct sbuf * s,const char * fmt,...)631 sbuf_printf(struct sbuf *s, const char *fmt, ...)
632 {
633 __va_list ap;
634 int result;
635
636 __va_start(ap, fmt);
637 result = sbuf_vprintf(s, fmt, ap);
638 __va_end(ap);
639 return (result);
640 }
641
642 /*
643 * Append a character to an sbuf.
644 */
645 int
sbuf_putc(struct sbuf * s,int c)646 sbuf_putc(struct sbuf *s, int c)
647 {
648
649 sbuf_put_byte(s, c);
650 if (s->s_error != 0)
651 return (-1);
652 return (0);
653 }
654
655 /*
656 * Trim whitespace characters from end of an sbuf.
657 */
658 int
sbuf_trim(struct sbuf * s)659 sbuf_trim(struct sbuf *s)
660 {
661
662 assert_sbuf_integrity(s);
663 assert_sbuf_state(s, 0);
664 KASSERT(s->s_drain_func == NULL,
665 ("%s makes no sense on sbuf %p with drain", __func__, s));
666
667 if (s->s_error != 0)
668 return (-1);
669
670 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
671 --s->s_len;
672 if (SBUF_ISSECTION(s))
673 s->s_sect_len--;
674 }
675
676 return (0);
677 }
678
679 /*
680 * Check if an sbuf has an error.
681 */
682 int
sbuf_error(const struct sbuf * s)683 sbuf_error(const struct sbuf *s)
684 {
685
686 return (s->s_error);
687 }
688
689 /*
690 * Finish off an sbuf.
691 */
692 int
sbuf_finish(struct sbuf * s)693 sbuf_finish(struct sbuf *s)
694 {
695
696 assert_sbuf_integrity(s);
697 assert_sbuf_state(s, 0);
698
699 if (s->s_drain_func != NULL) {
700 while (s->s_len > 0 && s->s_error == 0)
701 s->s_error = sbuf_drain(s);
702 }
703 s->s_buf[s->s_len] = '\0';
704 SBUF_SETFLAG(s, SBUF_FINISHED);
705 #ifdef _KERNEL
706 return (s->s_error);
707 #else
708 if (s->s_error != 0) {
709 errno = s->s_error;
710 return (-1);
711 }
712 return (0);
713 #endif
714 }
715
716 /*
717 * Return a pointer to the sbuf data.
718 */
719 char *
sbuf_data(struct sbuf * s)720 sbuf_data(struct sbuf *s)
721 {
722
723 assert_sbuf_integrity(s);
724 assert_sbuf_state(s, SBUF_FINISHED);
725 KASSERT(s->s_drain_func == NULL,
726 ("%s makes no sense on sbuf %p with drain", __func__, s));
727
728 return (s->s_buf);
729 }
730
731 /*
732 * Return the length of the sbuf data.
733 */
734 ssize_t
sbuf_len(struct sbuf * s)735 sbuf_len(struct sbuf *s)
736 {
737
738 assert_sbuf_integrity(s);
739 /* don't care if it's finished or not */
740 KASSERT(s->s_drain_func == NULL,
741 ("%s makes no sense on sbuf %p with drain", __func__, s));
742
743 if (s->s_error != 0)
744 return (-1);
745 return (s->s_len);
746 }
747
748 /*
749 * Clear an sbuf, free its buffer if necessary.
750 */
751 void
sbuf_delete(struct sbuf * s)752 sbuf_delete(struct sbuf *s)
753 {
754 int isdyn;
755
756 assert_sbuf_integrity(s);
757 /* don't care if it's finished or not */
758
759 if (SBUF_ISDYNAMIC(s))
760 SBFREE(s->s_buf);
761 isdyn = SBUF_ISDYNSTRUCT(s);
762 memset(s, 0, sizeof(*s));
763 if (isdyn)
764 SBFREE(s);
765 }
766
767 /*
768 * Check if an sbuf has been finished.
769 */
770 int
sbuf_done(const struct sbuf * s)771 sbuf_done(const struct sbuf *s)
772 {
773
774 return (SBUF_ISFINISHED(s));
775 }
776
777 /*
778 * Start a section.
779 */
780 void
sbuf_start_section(struct sbuf * s,ssize_t * old_lenp)781 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
782 {
783
784 assert_sbuf_integrity(s);
785 assert_sbuf_state(s, 0);
786
787 if (!SBUF_ISSECTION(s)) {
788 KASSERT(s->s_sect_len == 0,
789 ("s_sect_len != 0 when starting a section"));
790 if (old_lenp != NULL)
791 *old_lenp = -1;
792 SBUF_SETFLAG(s, SBUF_INSECTION);
793 } else {
794 KASSERT(old_lenp != NULL,
795 ("s_sect_len should be saved when starting a subsection"));
796 *old_lenp = s->s_sect_len;
797 s->s_sect_len = 0;
798 }
799 }
800
801 /*
802 * End the section padding to the specified length with the specified
803 * character.
804 */
805 ssize_t
sbuf_end_section(struct sbuf * s,ssize_t old_len,size_t pad,int c)806 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
807 {
808 ssize_t len;
809
810 assert_sbuf_integrity(s);
811 assert_sbuf_state(s, 0);
812 KASSERT(SBUF_ISSECTION(s),
813 ("attempt to end a section when not in a section"));
814
815 if (pad > 1) {
816 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
817 for (; s->s_error == 0 && len > 0; len--)
818 sbuf_put_byte(s, c);
819 }
820 len = s->s_sect_len;
821 if (old_len == -1) {
822 s->s_sect_len = 0;
823 SBUF_CLEARFLAG(s, SBUF_INSECTION);
824 } else {
825 s->s_sect_len += old_len;
826 }
827 if (s->s_error != 0)
828 return (-1);
829 return (len);
830 }
831