subr_sbuf.c revision 255805
1/*- 2 * Copyright (c) 2000-2008 Poul-Henning Kamp 3 * Copyright (c) 2000-2008 Dag-Erling Co��dan Sm��rgrav 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: head/sys/kern/subr_sbuf.c 255805 2013-09-22 23:47:56Z des $"); 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/malloc.h> 39#include <sys/systm.h> 40#include <sys/uio.h> 41#include <machine/stdarg.h> 42#else /* _KERNEL */ 43#include <ctype.h> 44#include <errno.h> 45#include <stdarg.h> 46#include <stdio.h> 47#include <stdlib.h> 48#include <string.h> 49#endif /* _KERNEL */ 50 51#include <sys/sbuf.h> 52 53#ifdef _KERNEL 54static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers"); 55#define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK|M_ZERO) 56#define SBFREE(buf) free(buf, M_SBUF) 57#else /* _KERNEL */ 58#define KASSERT(e, m) 59#define SBMALLOC(size) calloc(1, size) 60#define SBFREE(buf) free(buf) 61#endif /* _KERNEL */ 62 63/* 64 * Predicates 65 */ 66#define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC) 67#define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT) 68#define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED) 69#define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1) 70#define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1)) 71#define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND) 72#define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION) 73 74/* 75 * Set / clear flags 76 */ 77#define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0) 78#define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0) 79 80#define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */ 81 82#ifdef PAGE_SIZE 83#define SBUF_MAXEXTENDSIZE PAGE_SIZE 84#define SBUF_MAXEXTENDINCR PAGE_SIZE 85#else 86#define SBUF_MAXEXTENDSIZE 4096 87#define SBUF_MAXEXTENDINCR 4096 88#endif 89 90/* 91 * Debugging support 92 */ 93#if defined(_KERNEL) && defined(INVARIANTS) 94 95static void 96_assert_sbuf_integrity(const char *fun, struct sbuf *s) 97{ 98 99 KASSERT(s != NULL, 100 ("%s called with a NULL sbuf pointer", fun)); 101 KASSERT(s->s_buf != NULL, 102 ("%s called with uninitialized or corrupt sbuf", fun)); 103 KASSERT(s->s_len < s->s_size, 104 ("wrote past end of sbuf (%jd >= %jd)", 105 (intmax_t)s->s_len, (intmax_t)s->s_size)); 106} 107 108static void 109_assert_sbuf_state(const char *fun, struct sbuf *s, int state) 110{ 111 112 KASSERT((s->s_flags & SBUF_FINISHED) == state, 113 ("%s called with %sfinished or corrupt sbuf", fun, 114 (state ? "un" : ""))); 115} 116 117#define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s)) 118#define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i)) 119 120#else /* _KERNEL && INVARIANTS */ 121 122#define assert_sbuf_integrity(s) do { } while (0) 123#define assert_sbuf_state(s, i) do { } while (0) 124 125#endif /* _KERNEL && INVARIANTS */ 126 127#ifdef CTASSERT 128CTASSERT(powerof2(SBUF_MAXEXTENDSIZE)); 129CTASSERT(powerof2(SBUF_MAXEXTENDINCR)); 130#endif 131 132static int 133sbuf_extendsize(int size) 134{ 135 int newsize; 136 137 if (size < (int)SBUF_MAXEXTENDSIZE) { 138 newsize = SBUF_MINEXTENDSIZE; 139 while (newsize < size) 140 newsize *= 2; 141 } else { 142 newsize = roundup2(size, SBUF_MAXEXTENDINCR); 143 } 144 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size)); 145 return (newsize); 146} 147 148/* 149 * Extend an sbuf. 150 */ 151static int 152sbuf_extend(struct sbuf *s, int addlen) 153{ 154 char *newbuf; 155 int newsize; 156 157 if (!SBUF_CANEXTEND(s)) 158 return (-1); 159 newsize = sbuf_extendsize(s->s_size + addlen); 160 newbuf = SBMALLOC(newsize); 161 if (newbuf == NULL) 162 return (-1); 163 memcpy(newbuf, s->s_buf, s->s_size); 164 if (SBUF_ISDYNAMIC(s)) 165 SBFREE(s->s_buf); 166 else 167 SBUF_SETFLAG(s, SBUF_DYNAMIC); 168 s->s_buf = newbuf; 169 s->s_size = newsize; 170 return (0); 171} 172 173/* 174 * Initialize the internals of an sbuf. 175 * If buf is non-NULL, it points to a static or already-allocated string 176 * big enough to hold at least length characters. 177 */ 178static struct sbuf * 179sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags) 180{ 181 182 memset(s, 0, sizeof(*s)); 183 s->s_flags = flags; 184 s->s_size = length; 185 s->s_buf = buf; 186 187 if ((s->s_flags & SBUF_AUTOEXTEND) == 0) { 188 KASSERT(s->s_size >= 0, 189 ("attempt to create a too small sbuf")); 190 } 191 192 if (s->s_buf != NULL) 193 return (s); 194 195 if ((flags & SBUF_AUTOEXTEND) != 0) 196 s->s_size = sbuf_extendsize(s->s_size); 197 198 s->s_buf = SBMALLOC(s->s_size); 199 if (s->s_buf == NULL) 200 return (NULL); 201 SBUF_SETFLAG(s, SBUF_DYNAMIC); 202 return (s); 203} 204 205/* 206 * Initialize an sbuf. 207 * If buf is non-NULL, it points to a static or already-allocated string 208 * big enough to hold at least length characters. 209 */ 210struct sbuf * 211sbuf_new(struct sbuf *s, char *buf, int length, int flags) 212{ 213 214 KASSERT(length >= 0, 215 ("attempt to create an sbuf of negative length (%d)", length)); 216 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0, 217 ("%s called with invalid flags", __func__)); 218 219 flags &= SBUF_USRFLAGMSK; 220 if (s != NULL) 221 return (sbuf_newbuf(s, buf, length, flags)); 222 223 s = SBMALLOC(sizeof(*s)); 224 if (s == NULL) 225 return (NULL); 226 if (sbuf_newbuf(s, buf, length, flags) == NULL) { 227 SBFREE(s); 228 return (NULL); 229 } 230 SBUF_SETFLAG(s, SBUF_DYNSTRUCT); 231 return (s); 232} 233 234#ifdef _KERNEL 235/* 236 * Create an sbuf with uio data 237 */ 238struct sbuf * 239sbuf_uionew(struct sbuf *s, struct uio *uio, int *error) 240{ 241 242 KASSERT(uio != NULL, 243 ("%s called with NULL uio pointer", __func__)); 244 KASSERT(error != NULL, 245 ("%s called with NULL error pointer", __func__)); 246 247 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0); 248 if (s == NULL) { 249 *error = ENOMEM; 250 return (NULL); 251 } 252 *error = uiomove(s->s_buf, uio->uio_resid, uio); 253 if (*error != 0) { 254 sbuf_delete(s); 255 return (NULL); 256 } 257 s->s_len = s->s_size - 1; 258 if (SBUF_ISSECTION(s)) 259 s->s_sect_len = s->s_size - 1; 260 *error = 0; 261 return (s); 262} 263#endif 264 265/* 266 * Clear an sbuf and reset its position. 267 */ 268void 269sbuf_clear(struct sbuf *s) 270{ 271 272 assert_sbuf_integrity(s); 273 /* don't care if it's finished or not */ 274 275 SBUF_CLEARFLAG(s, SBUF_FINISHED); 276 s->s_error = 0; 277 s->s_len = 0; 278 s->s_sect_len = 0; 279} 280 281/* 282 * Set the sbuf's end position to an arbitrary value. 283 * Effectively truncates the sbuf at the new position. 284 */ 285int 286sbuf_setpos(struct sbuf *s, ssize_t pos) 287{ 288 289 assert_sbuf_integrity(s); 290 assert_sbuf_state(s, 0); 291 292 KASSERT(pos >= 0, 293 ("attempt to seek to a negative position (%jd)", (intmax_t)pos)); 294 KASSERT(pos < s->s_size, 295 ("attempt to seek past end of sbuf (%jd >= %jd)", 296 (intmax_t)pos, (intmax_t)s->s_size)); 297 KASSERT(!SBUF_ISSECTION(s), 298 ("attempt to seek when in a section")); 299 300 if (pos < 0 || pos > s->s_len) 301 return (-1); 302 s->s_len = pos; 303 return (0); 304} 305 306/* 307 * Set up a drain function and argument on an sbuf to flush data to 308 * when the sbuf buffer overflows. 309 */ 310void 311sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx) 312{ 313 314 assert_sbuf_state(s, 0); 315 assert_sbuf_integrity(s); 316 KASSERT(func == s->s_drain_func || s->s_len == 0, 317 ("Cannot change drain to %p on non-empty sbuf %p", func, s)); 318 s->s_drain_func = func; 319 s->s_drain_arg = ctx; 320} 321 322/* 323 * Call the drain and process the return. 324 */ 325static int 326sbuf_drain(struct sbuf *s) 327{ 328 int len; 329 330 KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s)); 331 KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s)); 332 len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len); 333 if (len < 0) { 334 s->s_error = -len; 335 return (s->s_error); 336 } 337 KASSERT(len > 0 && len <= s->s_len, 338 ("Bad drain amount %d for sbuf %p", len, s)); 339 s->s_len -= len; 340 /* 341 * Fast path for the expected case where all the data was 342 * drained. 343 */ 344 if (s->s_len == 0) 345 return (0); 346 /* 347 * Move the remaining characters to the beginning of the 348 * string. 349 */ 350 memmove(s->s_buf, s->s_buf + len, s->s_len); 351 return (0); 352} 353 354/* 355 * Append a byte to an sbuf. This is the core function for appending 356 * to an sbuf and is the main place that deals with extending the 357 * buffer and marking overflow. 358 */ 359static void 360sbuf_put_byte(struct sbuf *s, int c) 361{ 362 363 assert_sbuf_integrity(s); 364 assert_sbuf_state(s, 0); 365 366 if (s->s_error != 0) 367 return; 368 if (SBUF_FREESPACE(s) <= 0) { 369 /* 370 * If there is a drain, use it, otherwise extend the 371 * buffer. 372 */ 373 if (s->s_drain_func != NULL) 374 (void)sbuf_drain(s); 375 else if (sbuf_extend(s, 1) < 0) 376 s->s_error = ENOMEM; 377 if (s->s_error != 0) 378 return; 379 } 380 s->s_buf[s->s_len++] = c; 381 if (SBUF_ISSECTION(s)) 382 s->s_sect_len++; 383} 384 385/* 386 * Append a byte string to an sbuf. 387 */ 388int 389sbuf_bcat(struct sbuf *s, const void *buf, size_t len) 390{ 391 const char *str = buf; 392 const char *end = str + len; 393 394 assert_sbuf_integrity(s); 395 assert_sbuf_state(s, 0); 396 397 if (s->s_error != 0) 398 return (-1); 399 for (; str < end; str++) { 400 sbuf_put_byte(s, *str); 401 if (s->s_error != 0) 402 return (-1); 403 } 404 return (0); 405} 406 407#ifdef _KERNEL 408/* 409 * Copy a byte string from userland into an sbuf. 410 */ 411int 412sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len) 413{ 414 415 assert_sbuf_integrity(s); 416 assert_sbuf_state(s, 0); 417 KASSERT(s->s_drain_func == NULL, 418 ("Nonsensical copyin to sbuf %p with a drain", s)); 419 420 if (s->s_error != 0) 421 return (-1); 422 if (len == 0) 423 return (0); 424 if (len > SBUF_FREESPACE(s)) { 425 sbuf_extend(s, len - SBUF_FREESPACE(s)); 426 if (SBUF_FREESPACE(s) < len) 427 len = SBUF_FREESPACE(s); 428 } 429 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0) 430 return (-1); 431 s->s_len += len; 432 433 return (0); 434} 435#endif 436 437/* 438 * Copy a byte string into an sbuf. 439 */ 440int 441sbuf_bcpy(struct sbuf *s, const void *buf, size_t len) 442{ 443 444 assert_sbuf_integrity(s); 445 assert_sbuf_state(s, 0); 446 447 sbuf_clear(s); 448 return (sbuf_bcat(s, buf, len)); 449} 450 451/* 452 * Append a string to an sbuf. 453 */ 454int 455sbuf_cat(struct sbuf *s, const char *str) 456{ 457 458 assert_sbuf_integrity(s); 459 assert_sbuf_state(s, 0); 460 461 if (s->s_error != 0) 462 return (-1); 463 464 while (*str != '\0') { 465 sbuf_put_byte(s, *str++); 466 if (s->s_error != 0) 467 return (-1); 468 } 469 return (0); 470} 471 472#ifdef _KERNEL 473/* 474 * Append a string from userland to an sbuf. 475 */ 476int 477sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len) 478{ 479 size_t done; 480 481 assert_sbuf_integrity(s); 482 assert_sbuf_state(s, 0); 483 KASSERT(s->s_drain_func == NULL, 484 ("Nonsensical copyin to sbuf %p with a drain", s)); 485 486 if (s->s_error != 0) 487 return (-1); 488 489 if (len == 0) 490 len = SBUF_FREESPACE(s); /* XXX return 0? */ 491 if (len > SBUF_FREESPACE(s)) { 492 sbuf_extend(s, len); 493 if (SBUF_FREESPACE(s) < len) 494 len = SBUF_FREESPACE(s); 495 } 496 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) { 497 case ENAMETOOLONG: 498 s->s_error = ENOMEM; 499 /* fall through */ 500 case 0: 501 s->s_len += done - 1; 502 if (SBUF_ISSECTION(s)) 503 s->s_sect_len += done - 1; 504 break; 505 default: 506 return (-1); /* XXX */ 507 } 508 509 return (done); 510} 511#endif 512 513/* 514 * Copy a string into an sbuf. 515 */ 516int 517sbuf_cpy(struct sbuf *s, const char *str) 518{ 519 520 assert_sbuf_integrity(s); 521 assert_sbuf_state(s, 0); 522 523 sbuf_clear(s); 524 return (sbuf_cat(s, str)); 525} 526 527/* 528 * Format the given argument list and append the resulting string to an sbuf. 529 */ 530#ifdef _KERNEL 531 532/* 533 * Append a non-NUL character to an sbuf. This prototype signature is 534 * suitable for use with kvprintf(9). 535 */ 536static void 537sbuf_putc_func(int c, void *arg) 538{ 539 540 if (c != '\0') 541 sbuf_put_byte(arg, c); 542} 543 544int 545sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap) 546{ 547 548 assert_sbuf_integrity(s); 549 assert_sbuf_state(s, 0); 550 551 KASSERT(fmt != NULL, 552 ("%s called with a NULL format string", __func__)); 553 554 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap); 555 if (s->s_error != 0) 556 return (-1); 557 return (0); 558} 559#else /* !_KERNEL */ 560int 561sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap) 562{ 563 va_list ap_copy; 564 int error, len; 565 566 assert_sbuf_integrity(s); 567 assert_sbuf_state(s, 0); 568 569 KASSERT(fmt != NULL, 570 ("%s called with a NULL format string", __func__)); 571 572 if (s->s_error != 0) 573 return (-1); 574 575 /* 576 * For the moment, there is no way to get vsnprintf(3) to hand 577 * back a character at a time, to push everything into 578 * sbuf_putc_func() as was done for the kernel. 579 * 580 * In userspace, while drains are useful, there's generally 581 * not a problem attempting to malloc(3) on out of space. So 582 * expand a userland sbuf if there is not enough room for the 583 * data produced by sbuf_[v]printf(3). 584 */ 585 586 error = 0; 587 do { 588 va_copy(ap_copy, ap); 589 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1, 590 fmt, ap_copy); 591 va_end(ap_copy); 592 593 if (SBUF_FREESPACE(s) >= len) 594 break; 595 /* Cannot print with the current available space. */ 596 if (s->s_drain_func != NULL && s->s_len > 0) 597 error = sbuf_drain(s); 598 else 599 error = sbuf_extend(s, len - SBUF_FREESPACE(s)); 600 } while (error == 0); 601 602 /* 603 * s->s_len is the length of the string, without the terminating nul. 604 * When updating s->s_len, we must subtract 1 from the length that 605 * we passed into vsnprintf() because that length includes the 606 * terminating nul. 607 * 608 * vsnprintf() returns the amount that would have been copied, 609 * given sufficient space, so don't over-increment s_len. 610 */ 611 if (SBUF_FREESPACE(s) < len) 612 len = SBUF_FREESPACE(s); 613 s->s_len += len; 614 if (SBUF_ISSECTION(s)) 615 s->s_sect_len += len; 616 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s)) 617 s->s_error = ENOMEM; 618 619 KASSERT(s->s_len < s->s_size, 620 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size)); 621 622 if (s->s_error != 0) 623 return (-1); 624 return (0); 625} 626#endif /* _KERNEL */ 627 628/* 629 * Format the given arguments and append the resulting string to an sbuf. 630 */ 631int 632sbuf_printf(struct sbuf *s, const char *fmt, ...) 633{ 634 va_list ap; 635 int result; 636 637 va_start(ap, fmt); 638 result = sbuf_vprintf(s, fmt, ap); 639 va_end(ap); 640 return (result); 641} 642 643/* 644 * Append a character to an sbuf. 645 */ 646int 647sbuf_putc(struct sbuf *s, int c) 648{ 649 650 sbuf_put_byte(s, c); 651 if (s->s_error != 0) 652 return (-1); 653 return (0); 654} 655 656/* 657 * Trim whitespace characters from end of an sbuf. 658 */ 659int 660sbuf_trim(struct sbuf *s) 661{ 662 663 assert_sbuf_integrity(s); 664 assert_sbuf_state(s, 0); 665 KASSERT(s->s_drain_func == NULL, 666 ("%s makes no sense on sbuf %p with drain", __func__, s)); 667 668 if (s->s_error != 0) 669 return (-1); 670 671 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) { 672 --s->s_len; 673 if (SBUF_ISSECTION(s)) 674 s->s_sect_len--; 675 } 676 677 return (0); 678} 679 680/* 681 * Check if an sbuf has an error. 682 */ 683int 684sbuf_error(const struct sbuf *s) 685{ 686 687 return (s->s_error); 688} 689 690/* 691 * Finish off an sbuf. 692 */ 693int 694sbuf_finish(struct sbuf *s) 695{ 696 697 assert_sbuf_integrity(s); 698 assert_sbuf_state(s, 0); 699 700 if (s->s_drain_func != NULL) { 701 while (s->s_len > 0 && s->s_error == 0) 702 s->s_error = sbuf_drain(s); 703 } 704 s->s_buf[s->s_len] = '\0'; 705 SBUF_SETFLAG(s, SBUF_FINISHED); 706#ifdef _KERNEL 707 return (s->s_error); 708#else 709 if (s->s_error != 0) { 710 errno = s->s_error; 711 return (-1); 712 } 713 return (0); 714#endif 715} 716 717/* 718 * Return a pointer to the sbuf data. 719 */ 720char * 721sbuf_data(struct sbuf *s) 722{ 723 724 assert_sbuf_integrity(s); 725 assert_sbuf_state(s, SBUF_FINISHED); 726 KASSERT(s->s_drain_func == NULL, 727 ("%s makes no sense on sbuf %p with drain", __func__, s)); 728 729 return (s->s_buf); 730} 731 732/* 733 * Return the length of the sbuf data. 734 */ 735ssize_t 736sbuf_len(struct sbuf *s) 737{ 738 739 assert_sbuf_integrity(s); 740 /* don't care if it's finished or not */ 741 KASSERT(s->s_drain_func == NULL, 742 ("%s makes no sense on sbuf %p with drain", __func__, s)); 743 744 if (s->s_error != 0) 745 return (-1); 746 return (s->s_len); 747} 748 749/* 750 * Clear an sbuf, free its buffer if necessary. 751 */ 752void 753sbuf_delete(struct sbuf *s) 754{ 755 int isdyn; 756 757 assert_sbuf_integrity(s); 758 /* don't care if it's finished or not */ 759 760 if (SBUF_ISDYNAMIC(s)) 761 SBFREE(s->s_buf); 762 isdyn = SBUF_ISDYNSTRUCT(s); 763 memset(s, 0, sizeof(*s)); 764 if (isdyn) 765 SBFREE(s); 766} 767 768/* 769 * Check if an sbuf has been finished. 770 */ 771int 772sbuf_done(const struct sbuf *s) 773{ 774 775 return (SBUF_ISFINISHED(s)); 776} 777 778/* 779 * Start a section. 780 */ 781void 782sbuf_start_section(struct sbuf *s, ssize_t *old_lenp) 783{ 784 785 assert_sbuf_integrity(s); 786 assert_sbuf_state(s, 0); 787 788 if (!SBUF_ISSECTION(s)) { 789 KASSERT(s->s_sect_len == 0, 790 ("s_sect_len != 0 when starting a section")); 791 if (old_lenp != NULL) 792 *old_lenp = -1; 793 SBUF_SETFLAG(s, SBUF_INSECTION); 794 } else { 795 KASSERT(old_lenp != NULL, 796 ("s_sect_len should be saved when starting a subsection")); 797 *old_lenp = s->s_sect_len; 798 s->s_sect_len = 0; 799 } 800} 801 802/* 803 * End the section padding to the specified length with the specified 804 * character. 805 */ 806ssize_t 807sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c) 808{ 809 ssize_t len; 810 811 assert_sbuf_integrity(s); 812 assert_sbuf_state(s, 0); 813 KASSERT(SBUF_ISSECTION(s), 814 ("attempt to end a section when not in a section")); 815 816 if (pad > 1) { 817 len = roundup(s->s_sect_len, pad) - s->s_sect_len; 818 for (; s->s_error == 0 && len > 0; len--) 819 sbuf_put_byte(s, c); 820 } 821 len = s->s_sect_len; 822 if (old_len == -1) { 823 s->s_sect_len = 0; 824 SBUF_CLEARFLAG(s, SBUF_INSECTION); 825 } else { 826 s->s_sect_len += old_len; 827 } 828 if (s->s_error != 0) 829 return (-1); 830 return (len); 831} 832