FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_sbuf.c
1 /*-
2 * Copyright (c) 2000 Poul-Henning Kamp and Dag-Erling Coïdan Smørgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 */
28
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD: releng/5.2/sys/kern/subr_sbuf.c 116182 2003-06-11 00:56:59Z obrien $");
31
32 #include <sys/param.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 MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
53 #define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK)
54 #define SBFREE(buf) free(buf, M_SBUF)
55 #else /* _KERNEL */
56 #define KASSERT(e, m)
57 #define SBMALLOC(size) malloc(size)
58 #define SBFREE(buf) free(buf)
59 #define min(x,y) MIN(x,y)
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_HASOVERFLOWED(s) ((s)->s_flags & SBUF_OVERFLOWED)
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
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 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
81 #define SBUF_MAXEXTENDINCR PAGE_SIZE
82
83 /*
84 * Debugging support
85 */
86 #if defined(_KERNEL) && defined(INVARIANTS)
87 static void
88 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
89 {
90 KASSERT(s != NULL,
91 ("%s called with a NULL sbuf pointer", fun));
92 KASSERT(s->s_buf != NULL,
93 ("%s called with uninitialized or corrupt sbuf", fun));
94 KASSERT(s->s_len < s->s_size,
95 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
96 }
97
98 static void
99 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
100 {
101 KASSERT((s->s_flags & SBUF_FINISHED) == state,
102 ("%s called with %sfinished or corrupt sbuf", fun,
103 (state ? "un" : "")));
104 }
105 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
106 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
107 #else /* _KERNEL && INVARIANTS */
108 #define assert_sbuf_integrity(s) do { } while (0)
109 #define assert_sbuf_state(s, i) do { } while (0)
110 #endif /* _KERNEL && INVARIANTS */
111
112 static int
113 sbuf_extendsize(int size)
114 {
115 int newsize;
116
117 newsize = SBUF_MINEXTENDSIZE;
118 while (newsize < size) {
119 if (newsize < (int)SBUF_MAXEXTENDSIZE)
120 newsize *= 2;
121 else
122 newsize += SBUF_MAXEXTENDINCR;
123 }
124
125 return (newsize);
126 }
127
128
129 /*
130 * Extend an sbuf.
131 */
132 static int
133 sbuf_extend(struct sbuf *s, int addlen)
134 {
135 char *newbuf;
136 int newsize;
137
138 if (!SBUF_CANEXTEND(s))
139 return (-1);
140
141 newsize = sbuf_extendsize(s->s_size + addlen);
142 newbuf = (char *)SBMALLOC(newsize);
143 if (newbuf == NULL)
144 return (-1);
145 bcopy(s->s_buf, newbuf, s->s_size);
146 if (SBUF_ISDYNAMIC(s))
147 SBFREE(s->s_buf);
148 else
149 SBUF_SETFLAG(s, SBUF_DYNAMIC);
150 s->s_buf = newbuf;
151 s->s_size = newsize;
152 return (0);
153 }
154
155 /*
156 * Initialize an sbuf.
157 * If buf is non-NULL, it points to a static or already-allocated string
158 * big enough to hold at least length characters.
159 */
160 struct sbuf *
161 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
162 {
163 KASSERT(length >= 0,
164 ("attempt to create an sbuf of negative length (%d)", length));
165 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
166 ("%s called with invalid flags", __func__));
167
168 flags &= SBUF_USRFLAGMSK;
169 if (s == NULL) {
170 s = (struct sbuf *)SBMALLOC(sizeof *s);
171 if (s == NULL)
172 return (NULL);
173 bzero(s, sizeof *s);
174 s->s_flags = flags;
175 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
176 } else {
177 bzero(s, sizeof *s);
178 s->s_flags = flags;
179 }
180 s->s_size = length;
181 if (buf) {
182 s->s_buf = buf;
183 return (s);
184 }
185 if (flags & SBUF_AUTOEXTEND)
186 s->s_size = sbuf_extendsize(s->s_size);
187 s->s_buf = (char *)SBMALLOC(s->s_size);
188 if (s->s_buf == NULL) {
189 if (SBUF_ISDYNSTRUCT(s))
190 SBFREE(s);
191 return (NULL);
192 }
193 SBUF_SETFLAG(s, SBUF_DYNAMIC);
194 return (s);
195 }
196
197 #ifdef _KERNEL
198 /*
199 * Create an sbuf with uio data
200 */
201 struct sbuf *
202 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
203 {
204 KASSERT(uio != NULL,
205 ("%s called with NULL uio pointer", __func__));
206 KASSERT(error != NULL,
207 ("%s called with NULL error pointer", __func__));
208
209 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
210 if (s == NULL) {
211 *error = ENOMEM;
212 return (NULL);
213 }
214 *error = uiomove(s->s_buf, uio->uio_resid, uio);
215 if (*error != 0) {
216 sbuf_delete(s);
217 return (NULL);
218 }
219 s->s_len = s->s_size - 1;
220 *error = 0;
221 return (s);
222 }
223 #endif
224
225 /*
226 * Clear an sbuf and reset its position.
227 */
228 void
229 sbuf_clear(struct sbuf *s)
230 {
231 assert_sbuf_integrity(s);
232 /* don't care if it's finished or not */
233
234 SBUF_CLEARFLAG(s, SBUF_FINISHED);
235 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
236 s->s_len = 0;
237 }
238
239 /*
240 * Set the sbuf's end position to an arbitrary value.
241 * Effectively truncates the sbuf at the new position.
242 */
243 int
244 sbuf_setpos(struct sbuf *s, int pos)
245 {
246 assert_sbuf_integrity(s);
247 assert_sbuf_state(s, 0);
248
249 KASSERT(pos >= 0,
250 ("attempt to seek to a negative position (%d)", pos));
251 KASSERT(pos < s->s_size,
252 ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));
253
254 if (pos < 0 || pos > s->s_len)
255 return (-1);
256 s->s_len = pos;
257 return (0);
258 }
259
260 /*
261 * Append a byte string to an sbuf.
262 */
263 int
264 sbuf_bcat(struct sbuf *s, const char *str, size_t len)
265 {
266 assert_sbuf_integrity(s);
267 assert_sbuf_state(s, 0);
268
269 if (SBUF_HASOVERFLOWED(s))
270 return (-1);
271
272 for (; len; len--) {
273 if (!SBUF_HASROOM(s) && sbuf_extend(s, len) < 0)
274 break;
275 s->s_buf[s->s_len++] = *str++;
276 }
277 if (len) {
278 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
279 return (-1);
280 }
281 return (0);
282 }
283
284 #ifdef _KERNEL
285 /*
286 * Copy a byte string from userland into an sbuf.
287 */
288 int
289 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
290 {
291 assert_sbuf_integrity(s);
292 assert_sbuf_state(s, 0);
293
294 if (SBUF_HASOVERFLOWED(s))
295 return (-1);
296
297 if (len == 0)
298 return (0);
299 if (len > SBUF_FREESPACE(s)) {
300 sbuf_extend(s, len - SBUF_FREESPACE(s));
301 len = min(len, SBUF_FREESPACE(s));
302 }
303 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
304 return (-1);
305 s->s_len += len;
306
307 return (0);
308 }
309 #endif
310
311 /*
312 * Copy a byte string into an sbuf.
313 */
314 int
315 sbuf_bcpy(struct sbuf *s, const char *str, size_t len)
316 {
317 assert_sbuf_integrity(s);
318 assert_sbuf_state(s, 0);
319
320 sbuf_clear(s);
321 return (sbuf_bcat(s, str, len));
322 }
323
324 /*
325 * Append a string to an sbuf.
326 */
327 int
328 sbuf_cat(struct sbuf *s, const char *str)
329 {
330 assert_sbuf_integrity(s);
331 assert_sbuf_state(s, 0);
332
333 if (SBUF_HASOVERFLOWED(s))
334 return (-1);
335
336 while (*str) {
337 if (!SBUF_HASROOM(s) && sbuf_extend(s, strlen(str)) < 0)
338 break;
339 s->s_buf[s->s_len++] = *str++;
340 }
341 if (*str) {
342 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
343 return (-1);
344 }
345 return (0);
346 }
347
348 #ifdef _KERNEL
349 /*
350 * Append a string from userland to an sbuf.
351 */
352 int
353 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
354 {
355 size_t done;
356
357 assert_sbuf_integrity(s);
358 assert_sbuf_state(s, 0);
359
360 if (SBUF_HASOVERFLOWED(s))
361 return (-1);
362
363 if (len == 0)
364 len = SBUF_FREESPACE(s); /* XXX return 0? */
365 if (len > SBUF_FREESPACE(s)) {
366 sbuf_extend(s, len);
367 len = min(len, SBUF_FREESPACE(s));
368 }
369 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
370 case ENAMETOOLONG:
371 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
372 /* fall through */
373 case 0:
374 s->s_len += done - 1;
375 break;
376 default:
377 return (-1); /* XXX */
378 }
379
380 return (0);
381 }
382 #endif
383
384 /*
385 * Copy a string into an sbuf.
386 */
387 int
388 sbuf_cpy(struct sbuf *s, const char *str)
389 {
390 assert_sbuf_integrity(s);
391 assert_sbuf_state(s, 0);
392
393 sbuf_clear(s);
394 return (sbuf_cat(s, str));
395 }
396
397 /*
398 * Format the given argument list and append the resulting string to an sbuf.
399 */
400 int
401 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
402 {
403 va_list ap_copy;
404 int len;
405
406 assert_sbuf_integrity(s);
407 assert_sbuf_state(s, 0);
408
409 KASSERT(fmt != NULL,
410 ("%s called with a NULL format string", __func__));
411
412 if (SBUF_HASOVERFLOWED(s))
413 return (-1);
414
415 do {
416 va_copy(ap_copy, ap);
417 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
418 fmt, ap_copy);
419 va_end(ap_copy);
420 } while (len > SBUF_FREESPACE(s) &&
421 sbuf_extend(s, len - SBUF_FREESPACE(s)) == 0);
422
423 /*
424 * s->s_len is the length of the string, without the terminating nul.
425 * When updating s->s_len, we must subtract 1 from the length that
426 * we passed into vsnprintf() because that length includes the
427 * terminating nul.
428 *
429 * vsnprintf() returns the amount that would have been copied,
430 * given sufficient space, hence the min() calculation below.
431 */
432 s->s_len += min(len, SBUF_FREESPACE(s));
433 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
434 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
435
436 KASSERT(s->s_len < s->s_size,
437 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
438
439 if (SBUF_HASOVERFLOWED(s))
440 return (-1);
441 return (0);
442 }
443
444 /*
445 * Format the given arguments and append the resulting string to an sbuf.
446 */
447 int
448 sbuf_printf(struct sbuf *s, const char *fmt, ...)
449 {
450 va_list ap;
451 int result;
452
453 va_start(ap, fmt);
454 result = sbuf_vprintf(s, fmt, ap);
455 va_end(ap);
456 return(result);
457 }
458
459 /*
460 * Append a character to an sbuf.
461 */
462 int
463 sbuf_putc(struct sbuf *s, int c)
464 {
465 assert_sbuf_integrity(s);
466 assert_sbuf_state(s, 0);
467
468 if (SBUF_HASOVERFLOWED(s))
469 return (-1);
470
471 if (!SBUF_HASROOM(s) && sbuf_extend(s, 1) < 0) {
472 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
473 return (-1);
474 }
475 if (c != '\0')
476 s->s_buf[s->s_len++] = c;
477 return (0);
478 }
479
480 /*
481 * Trim whitespace characters from end of an sbuf.
482 */
483 int
484 sbuf_trim(struct sbuf *s)
485 {
486 assert_sbuf_integrity(s);
487 assert_sbuf_state(s, 0);
488
489 if (SBUF_HASOVERFLOWED(s))
490 return (-1);
491
492 while (s->s_len && isspace(s->s_buf[s->s_len-1]))
493 --s->s_len;
494
495 return (0);
496 }
497
498 /*
499 * Check if an sbuf overflowed
500 */
501 int
502 sbuf_overflowed(struct sbuf *s)
503 {
504 return SBUF_HASOVERFLOWED(s);
505 }
506
507 /*
508 * Finish off an sbuf.
509 */
510 void
511 sbuf_finish(struct sbuf *s)
512 {
513 assert_sbuf_integrity(s);
514 assert_sbuf_state(s, 0);
515
516 s->s_buf[s->s_len] = '\0';
517 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
518 SBUF_SETFLAG(s, SBUF_FINISHED);
519 }
520
521 /*
522 * Return a pointer to the sbuf data.
523 */
524 char *
525 sbuf_data(struct sbuf *s)
526 {
527 assert_sbuf_integrity(s);
528 assert_sbuf_state(s, SBUF_FINISHED);
529
530 return s->s_buf;
531 }
532
533 /*
534 * Return the length of the sbuf data.
535 */
536 int
537 sbuf_len(struct sbuf *s)
538 {
539 assert_sbuf_integrity(s);
540 /* don't care if it's finished or not */
541
542 if (SBUF_HASOVERFLOWED(s))
543 return (-1);
544 return s->s_len;
545 }
546
547 /*
548 * Clear an sbuf, free its buffer if necessary.
549 */
550 void
551 sbuf_delete(struct sbuf *s)
552 {
553 int isdyn;
554
555 assert_sbuf_integrity(s);
556 /* don't care if it's finished or not */
557
558 if (SBUF_ISDYNAMIC(s))
559 SBFREE(s->s_buf);
560 isdyn = SBUF_ISDYNSTRUCT(s);
561 bzero(s, sizeof *s);
562 if (isdyn)
563 SBFREE(s);
564 }
565
566 /*
567 * Check if an sbuf has been finished.
568 */
569 int
570 sbuf_done(struct sbuf *s)
571 {
572
573 return(SBUF_ISFINISHED(s));
574 }
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