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/6.3/sys/kern/subr_sbuf.c 173886 2007-11-24 19:45:58Z cvs2svn $");
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 static 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 void *buf, size_t len)
265 {
266 const char *str = buf;
267
268 assert_sbuf_integrity(s);
269 assert_sbuf_state(s, 0);
270
271 if (SBUF_HASOVERFLOWED(s))
272 return (-1);
273
274 for (; len; len--) {
275 if (!SBUF_HASROOM(s) && sbuf_extend(s, len) < 0)
276 break;
277 s->s_buf[s->s_len++] = *str++;
278 }
279 if (len) {
280 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
281 return (-1);
282 }
283 return (0);
284 }
285
286 #ifdef _KERNEL
287 /*
288 * Copy a byte string from userland into an sbuf.
289 */
290 int
291 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
292 {
293 assert_sbuf_integrity(s);
294 assert_sbuf_state(s, 0);
295
296 if (SBUF_HASOVERFLOWED(s))
297 return (-1);
298
299 if (len == 0)
300 return (0);
301 if (len > SBUF_FREESPACE(s)) {
302 sbuf_extend(s, len - SBUF_FREESPACE(s));
303 len = min(len, SBUF_FREESPACE(s));
304 }
305 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
306 return (-1);
307 s->s_len += len;
308
309 return (0);
310 }
311 #endif
312
313 /*
314 * Copy a byte string into an sbuf.
315 */
316 int
317 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
318 {
319 assert_sbuf_integrity(s);
320 assert_sbuf_state(s, 0);
321
322 sbuf_clear(s);
323 return (sbuf_bcat(s, buf, len));
324 }
325
326 /*
327 * Append a string to an sbuf.
328 */
329 int
330 sbuf_cat(struct sbuf *s, const char *str)
331 {
332 assert_sbuf_integrity(s);
333 assert_sbuf_state(s, 0);
334
335 if (SBUF_HASOVERFLOWED(s))
336 return (-1);
337
338 while (*str) {
339 if (!SBUF_HASROOM(s) && sbuf_extend(s, strlen(str)) < 0)
340 break;
341 s->s_buf[s->s_len++] = *str++;
342 }
343 if (*str) {
344 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
345 return (-1);
346 }
347 return (0);
348 }
349
350 #ifdef _KERNEL
351 /*
352 * Append a string from userland to an sbuf.
353 */
354 int
355 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
356 {
357 size_t done;
358
359 assert_sbuf_integrity(s);
360 assert_sbuf_state(s, 0);
361
362 if (SBUF_HASOVERFLOWED(s))
363 return (-1);
364
365 if (len == 0)
366 len = SBUF_FREESPACE(s); /* XXX return 0? */
367 if (len > SBUF_FREESPACE(s)) {
368 sbuf_extend(s, len);
369 len = min(len, SBUF_FREESPACE(s));
370 }
371 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
372 case ENAMETOOLONG:
373 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
374 /* fall through */
375 case 0:
376 s->s_len += done - 1;
377 break;
378 default:
379 return (-1); /* XXX */
380 }
381
382 return (0);
383 }
384 #endif
385
386 /*
387 * Copy a string into an sbuf.
388 */
389 int
390 sbuf_cpy(struct sbuf *s, const char *str)
391 {
392 assert_sbuf_integrity(s);
393 assert_sbuf_state(s, 0);
394
395 sbuf_clear(s);
396 return (sbuf_cat(s, str));
397 }
398
399 /*
400 * Format the given argument list and append the resulting string to an sbuf.
401 */
402 int
403 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
404 {
405 va_list ap_copy;
406 int len;
407
408 assert_sbuf_integrity(s);
409 assert_sbuf_state(s, 0);
410
411 KASSERT(fmt != NULL,
412 ("%s called with a NULL format string", __func__));
413
414 if (SBUF_HASOVERFLOWED(s))
415 return (-1);
416
417 do {
418 va_copy(ap_copy, ap);
419 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
420 fmt, ap_copy);
421 va_end(ap_copy);
422 } while (len > SBUF_FREESPACE(s) &&
423 sbuf_extend(s, len - SBUF_FREESPACE(s)) == 0);
424
425 /*
426 * s->s_len is the length of the string, without the terminating nul.
427 * When updating s->s_len, we must subtract 1 from the length that
428 * we passed into vsnprintf() because that length includes the
429 * terminating nul.
430 *
431 * vsnprintf() returns the amount that would have been copied,
432 * given sufficient space, hence the min() calculation below.
433 */
434 s->s_len += min(len, SBUF_FREESPACE(s));
435 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
436 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
437
438 KASSERT(s->s_len < s->s_size,
439 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
440
441 if (SBUF_HASOVERFLOWED(s))
442 return (-1);
443 return (0);
444 }
445
446 /*
447 * Format the given arguments and append the resulting string to an sbuf.
448 */
449 int
450 sbuf_printf(struct sbuf *s, const char *fmt, ...)
451 {
452 va_list ap;
453 int result;
454
455 va_start(ap, fmt);
456 result = sbuf_vprintf(s, fmt, ap);
457 va_end(ap);
458 return(result);
459 }
460
461 /*
462 * Append a character to an sbuf.
463 */
464 int
465 sbuf_putc(struct sbuf *s, int c)
466 {
467 assert_sbuf_integrity(s);
468 assert_sbuf_state(s, 0);
469
470 if (SBUF_HASOVERFLOWED(s))
471 return (-1);
472
473 if (!SBUF_HASROOM(s) && sbuf_extend(s, 1) < 0) {
474 SBUF_SETFLAG(s, SBUF_OVERFLOWED);
475 return (-1);
476 }
477 if (c != '\0')
478 s->s_buf[s->s_len++] = c;
479 return (0);
480 }
481
482 /*
483 * Trim whitespace characters from end of an sbuf.
484 */
485 int
486 sbuf_trim(struct sbuf *s)
487 {
488 assert_sbuf_integrity(s);
489 assert_sbuf_state(s, 0);
490
491 if (SBUF_HASOVERFLOWED(s))
492 return (-1);
493
494 while (s->s_len && isspace(s->s_buf[s->s_len-1]))
495 --s->s_len;
496
497 return (0);
498 }
499
500 /*
501 * Check if an sbuf overflowed
502 */
503 int
504 sbuf_overflowed(struct sbuf *s)
505 {
506 return SBUF_HASOVERFLOWED(s);
507 }
508
509 /*
510 * Finish off an sbuf.
511 */
512 void
513 sbuf_finish(struct sbuf *s)
514 {
515 assert_sbuf_integrity(s);
516 assert_sbuf_state(s, 0);
517
518 s->s_buf[s->s_len] = '\0';
519 SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
520 SBUF_SETFLAG(s, SBUF_FINISHED);
521 }
522
523 /*
524 * Return a pointer to the sbuf data.
525 */
526 char *
527 sbuf_data(struct sbuf *s)
528 {
529 assert_sbuf_integrity(s);
530 assert_sbuf_state(s, SBUF_FINISHED);
531
532 return s->s_buf;
533 }
534
535 /*
536 * Return the length of the sbuf data.
537 */
538 int
539 sbuf_len(struct sbuf *s)
540 {
541 assert_sbuf_integrity(s);
542 /* don't care if it's finished or not */
543
544 if (SBUF_HASOVERFLOWED(s))
545 return (-1);
546 return s->s_len;
547 }
548
549 /*
550 * Clear an sbuf, free its buffer if necessary.
551 */
552 void
553 sbuf_delete(struct sbuf *s)
554 {
555 int isdyn;
556
557 assert_sbuf_integrity(s);
558 /* don't care if it's finished or not */
559
560 if (SBUF_ISDYNAMIC(s))
561 SBFREE(s->s_buf);
562 isdyn = SBUF_ISDYNSTRUCT(s);
563 bzero(s, sizeof *s);
564 if (isdyn)
565 SBFREE(s);
566 }
567
568 /*
569 * Check if an sbuf has been finished.
570 */
571 int
572 sbuf_done(struct sbuf *s)
573 {
574
575 return(SBUF_ISFINISHED(s));
576 }
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