xref: /dragonfly/sys/kern/subr_sbuf.c (revision b4f25088) 
1 /*-
2  * Copyright (c) 2000 Poul-Henning Kamp and Dag-Erling Co�dan Sm�rgrav
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  *      $FreeBSD: src/sys/kern/subr_sbuf.c,v 1.11.2.2 2002/03/12 01:01:07 archie Exp $
29  */
30 
31 #include <sys/param.h>
32 
33 #ifdef _KERNEL
34 #include <sys/ctype.h>
35 #include <sys/kernel.h>
36 #include <sys/malloc.h>
37 #include <sys/systm.h>
38 #include <sys/uio.h>
39 #include <machine/stdarg.h>
40 #else /* _KERNEL */
41 #include <ctype.h>
42 #include <stdarg.h>
43 #include <stdio.h>
44 #include <stdlib.h>
45 #include <string.h>
46 #endif /* _KERNEL */
47 
48 #include <sys/sbuf.h>
49 
50 #ifdef _KERNEL
51 MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
52 #define SBMALLOC(size)		kmalloc(size, M_SBUF, M_WAITOK)
53 #define SBFREE(buf)		kfree(buf, M_SBUF)
54 #else /* _KERNEL */
55 #define KASSERT(e, m)
56 #define SBMALLOC(size)		malloc(size)
57 #define SBFREE(buf)		free(buf)
58 #define kvsnprintf		vsnprintf
59 #endif /* _KERNEL */
60 
61 /*
62  * Predicates
63  */
64 #define SBUF_ISDYNAMIC(s)	((s)->s_flags & SBUF_DYNAMIC)
65 #define SBUF_ISDYNSTRUCT(s)	((s)->s_flags & SBUF_DYNSTRUCT)
66 #define SBUF_ISFINISHED(s)	((s)->s_flags & SBUF_FINISHED)
67 #define SBUF_HASOVERFLOWED(s)	((s)->s_flags & SBUF_OVERFLOWED)
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 
72 /*
73  * Set / clear flags
74  */
75 #define SBUF_SETFLAG(s, f)	do { (s)->s_flags |= (f); } while (0)
76 #define SBUF_CLEARFLAG(s, f)	do { (s)->s_flags &= ~(f); } while (0)
77 
78 #define SBUF_MINEXTENDSIZE	16		/* Should be power of 2. */
79 #define SBUF_MAXEXTENDSIZE	PAGE_SIZE
80 #define SBUF_MAXEXTENDINCR	PAGE_SIZE
81 
82 /*
83  * Debugging support
84  */
85 #if defined(_KERNEL) && defined(INVARIANTS)
86 static void
87 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
88 {
89 	KASSERT(s != NULL,
90 	    ("%s called with a NULL sbuf pointer", fun));
91 	KASSERT(s->s_buf != NULL,
92 	    ("%s called with uninitialized or corrupt sbuf", fun));
93 	KASSERT(s->s_len < s->s_size,
94 	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
95 }
96 
97 static void
98 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
99 {
100 	KASSERT((s->s_flags & SBUF_FINISHED) == state,
101 	    ("%s called with %sfinished or corrupt sbuf", fun,
102 	    (state ? "un" : "")));
103 }
104 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
105 #define assert_sbuf_state(s, i)	 _assert_sbuf_state(__func__, (s), (i))
106 #else /* _KERNEL && INVARIANTS */
107 #define assert_sbuf_integrity(s) do { } while (0)
108 #define assert_sbuf_state(s, i)	 do { } while (0)
109 #endif /* _KERNEL && INVARIANTS */
110 
111 static int
112 sbuf_extendsize(int size)
113 {
114 	int newsize;
115 
116 	newsize = SBUF_MINEXTENDSIZE;
117 	while (newsize < size) {
118 		if (newsize < SBUF_MAXEXTENDSIZE)
119 			newsize *= 2;
120 		else
121 			newsize += SBUF_MAXEXTENDINCR;
122 	}
123 
124 	return (newsize);
125 }
126 
127 
128 /*
129  * Extend an sbuf.
130  */
131 static int
132 sbuf_extend(struct sbuf *s, int addlen)
133 {
134 	char *newbuf;
135 	int newsize;
136 
137 	if (!SBUF_CANEXTEND(s))
138 		return (-1);
139 
140 	newsize = sbuf_extendsize(s->s_size + addlen);
141 	newbuf = (char *)SBMALLOC(newsize);
142 	if (newbuf == NULL)
143 		return (-1);
144 	bcopy(s->s_buf, newbuf, s->s_size);
145 	if (SBUF_ISDYNAMIC(s))
146 		SBFREE(s->s_buf);
147 	else
148 		SBUF_SETFLAG(s, SBUF_DYNAMIC);
149 	s->s_buf = newbuf;
150 	s->s_size = newsize;
151 	return (0);
152 }
153 
154 /*
155  * Initialize an sbuf.
156  * If buf is non-NULL, it points to a static or already-allocated string
157  * big enough to hold at least length characters.
158  */
159 struct sbuf *
160 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
161 {
162 	KASSERT(length >= 0,
163 	    ("attempt to create an sbuf of negative length (%d)", length));
164 	KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
165 	    ("%s called with invalid flags", __func__));
166 
167 	flags &= SBUF_USRFLAGMSK;
168 	if (s == NULL) {
169 		s = (struct sbuf *)SBMALLOC(sizeof *s);
170 		if (s == NULL)
171 			return (NULL);
172 		bzero(s, sizeof *s);
173 		s->s_flags = flags;
174 		SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
175 	} else {
176 		bzero(s, sizeof *s);
177 		s->s_flags = flags;
178 	}
179 	s->s_size = length;
180 	if (buf) {
181 		s->s_buf = buf;
182 		return (s);
183 	}
184 	if (flags & SBUF_AUTOEXTEND)
185 		s->s_size = sbuf_extendsize(s->s_size);
186 	s->s_buf = (char *)SBMALLOC(s->s_size);
187 	if (s->s_buf == NULL) {
188 		if (SBUF_ISDYNSTRUCT(s))
189 			SBFREE(s);
190 		return (NULL);
191 	}
192 	SBUF_SETFLAG(s, SBUF_DYNAMIC);
193 	return (s);
194 }
195 
196 #ifdef _KERNEL
197 /*
198  * Create an sbuf with uio data
199  */
200 struct sbuf *
201 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
202 {
203 	KASSERT(uio != NULL,
204 	    ("%s called with NULL uio pointer", __func__));
205 	KASSERT(error != NULL,
206 	    ("%s called with NULL error pointer", __func__));
207 
208 	s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
209 	if (s == NULL) {
210 		*error = ENOMEM;
211 		return (NULL);
212 	}
213 	*error = uiomove(s->s_buf, uio->uio_resid, uio);
214 	if (*error != 0) {
215 		sbuf_delete(s);
216 		return (NULL);
217 	}
218 	s->s_len = s->s_size - 1;
219 	*error = 0;
220 	return (s);
221 }
222 #endif
223 
224 /*
225  * Clear an sbuf and reset its position.
226  */
227 void
228 sbuf_clear(struct sbuf *s)
229 {
230 	assert_sbuf_integrity(s);
231 	/* don't care if it's finished or not */
232 
233 	SBUF_CLEARFLAG(s, SBUF_FINISHED);
234 	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
235 	s->s_len = 0;
236 }
237 
238 /*
239  * Set the sbuf's end position to an arbitrary value.
240  * Effectively truncates the sbuf at the new position.
241  */
242 int
243 sbuf_setpos(struct sbuf *s, int pos)
244 {
245 	assert_sbuf_integrity(s);
246 	assert_sbuf_state(s, 0);
247 
248 	KASSERT(pos >= 0,
249 	    ("attempt to seek to a negative position (%d)", pos));
250 	KASSERT(pos < s->s_size,
251 	    ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));
252 
253 	if (pos < 0 || pos > s->s_len)
254 		return (-1);
255 	s->s_len = pos;
256 	return (0);
257 }
258 
259 /*
260  * Append a byte string to an sbuf.
261  */
262 int
263 sbuf_bcat(struct sbuf *s, const char *str, size_t len)
264 {
265 	assert_sbuf_integrity(s);
266 	assert_sbuf_state(s, 0);
267 
268 	if (SBUF_HASOVERFLOWED(s))
269 		return (-1);
270 
271 	for (; len; len--) {
272 		if (!SBUF_HASROOM(s) && sbuf_extend(s, len) < 0)
273 			break;
274 		s->s_buf[s->s_len++] = *str++;
275 	}
276 	if (len) {
277 		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
278 		return (-1);
279 	}
280 	return (0);
281 }
282 
283 #ifdef _KERNEL
284 /*
285  * Copy a byte string from userland into an sbuf.
286  */
287 int
288 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
289 {
290 	assert_sbuf_integrity(s);
291 	assert_sbuf_state(s, 0);
292 
293 	if (SBUF_HASOVERFLOWED(s))
294 		return (-1);
295 
296 	if (len == 0)
297 		return (0);
298 	if (len > SBUF_FREESPACE(s)) {
299 		sbuf_extend(s, len - SBUF_FREESPACE(s));
300 		len = MIN(len, SBUF_FREESPACE(s));
301 	}
302 	if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
303 		return (-1);
304 	s->s_len += len;
305 
306 	return (0);
307 }
308 #endif
309 
310 /*
311  * Copy a byte string into an sbuf.
312  */
313 int
314 sbuf_bcpy(struct sbuf *s, const char *str, size_t len)
315 {
316 	assert_sbuf_integrity(s);
317 	assert_sbuf_state(s, 0);
318 
319 	sbuf_clear(s);
320 	return (sbuf_bcat(s, str, len));
321 }
322 
323 /*
324  * Append a string to an sbuf.
325  */
326 int
327 sbuf_cat(struct sbuf *s, const char *str)
328 {
329 	assert_sbuf_integrity(s);
330 	assert_sbuf_state(s, 0);
331 
332 	if (SBUF_HASOVERFLOWED(s))
333 		return (-1);
334 
335 	while (*str) {
336 		if (!SBUF_HASROOM(s) && sbuf_extend(s, strlen(str)) < 0)
337 			break;
338 		s->s_buf[s->s_len++] = *str++;
339 	}
340 	if (*str) {
341 		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
342 		return (-1);
343 	}
344 	return (0);
345 }
346 
347 #ifdef _KERNEL
348 /*
349  * Append a string from userland to an sbuf.
350  */
351 int
352 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
353 {
354 	size_t done;
355 
356 	assert_sbuf_integrity(s);
357 	assert_sbuf_state(s, 0);
358 
359 	if (SBUF_HASOVERFLOWED(s))
360 		return (-1);
361 
362 	if (len == 0)
363 		len = SBUF_FREESPACE(s);	/* XXX return 0? */
364 	if (len > SBUF_FREESPACE(s)) {
365 		sbuf_extend(s, len);
366 		len = MIN(len, SBUF_FREESPACE(s));
367 	}
368 	switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
369 	case ENAMETOOLONG:
370 		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
371 		/* fall through */
372 	case 0:
373 		s->s_len += done - 1;
374 		break;
375 	default:
376 		return (-1);	/* XXX */
377 	}
378 
379 	return (0);
380 }
381 #endif
382 
383 /*
384  * Copy a string into an sbuf.
385  */
386 int
387 sbuf_cpy(struct sbuf *s, const char *str)
388 {
389 	assert_sbuf_integrity(s);
390 	assert_sbuf_state(s, 0);
391 
392 	sbuf_clear(s);
393 	return (sbuf_cat(s, str));
394 }
395 
396 /*
397  * Format the given argument list and append the resulting string to an sbuf.
398  */
399 int
400 sbuf_vprintf(struct sbuf *s, const char *fmt, __va_list ap)
401 {
402 	int len;
403 	__va_list ap_copy;
404 
405 	assert_sbuf_integrity(s);
406 	assert_sbuf_state(s, 0);
407 
408 	KASSERT(fmt != NULL,
409 	    ("%s called with a NULL format string", __func__));
410 
411 	if (SBUF_HASOVERFLOWED(s))
412 		return (-1);
413 
414 	do {
415 		__va_copy(ap_copy, ap);
416 		len = kvsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
417 				 fmt, ap_copy);
418 		__va_end(ap_copy);
419 	} while (len > SBUF_FREESPACE(s) &&
420 	    sbuf_extend(s, len - SBUF_FREESPACE(s)) == 0);
421 
422 	/*
423 	 * s->s_len is the length of the string, without the terminating nul.
424 	 * When updating s->s_len, we must subtract 1 from the length that
425 	 * we passed into kvsnprintf() because that length includes the
426 	 * terminating nul.
427 	 *
428 	 * kvsnprintf() returns the amount that would have been copied,
429 	 * given sufficient space, hence the min() calculation below.
430 	 */
431 	s->s_len += MIN(len, SBUF_FREESPACE(s));
432 	if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
433 		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
434 
435 	KASSERT(s->s_len < s->s_size,
436 	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
437 
438 	if (SBUF_HASOVERFLOWED(s))
439 		return (-1);
440 	return (0);
441 }
442 
443 /*
444  * Format the given arguments and append the resulting string to an sbuf.
445  */
446 int
447 sbuf_printf(struct sbuf *s, const char *fmt, ...)
448 {
449 	__va_list ap;
450 	int result;
451 
452 	__va_start(ap, fmt);
453 	result = sbuf_vprintf(s, fmt, ap);
454 	__va_end(ap);
455 	return(result);
456 }
457 
458 /*
459  * Append a character to an sbuf.
460  */
461 int
462 sbuf_putc(struct sbuf *s, int c)
463 {
464 	assert_sbuf_integrity(s);
465 	assert_sbuf_state(s, 0);
466 
467 	if (SBUF_HASOVERFLOWED(s))
468 		return (-1);
469 
470 	if (!SBUF_HASROOM(s) && sbuf_extend(s, 1) < 0) {
471 		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
472 		return (-1);
473 	}
474 	if (c != '\0')
475 	    s->s_buf[s->s_len++] = c;
476 	return (0);
477 }
478 
479 /*
480  * Trim whitespace characters from end of an sbuf.
481  */
482 int
483 sbuf_trim(struct sbuf *s)
484 {
485 	assert_sbuf_integrity(s);
486 	assert_sbuf_state(s, 0);
487 
488 	if (SBUF_HASOVERFLOWED(s))
489 		return (-1);
490 
491 	while (s->s_len && isspace(s->s_buf[s->s_len-1]))
492 		--s->s_len;
493 
494 	return (0);
495 }
496 
497 /*
498  * Check if an sbuf overflowed
499  */
500 int
501 sbuf_overflowed(struct sbuf *s)
502 {
503     return SBUF_HASOVERFLOWED(s);
504 }
505 
506 /*
507  * Finish off an sbuf.
508  */
509 void
510 sbuf_finish(struct sbuf *s)
511 {
512 	assert_sbuf_integrity(s);
513 	assert_sbuf_state(s, 0);
514 
515 	s->s_buf[s->s_len] = '\0';
516 	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
517 	SBUF_SETFLAG(s, SBUF_FINISHED);
518 }
519 
520 /*
521  * Return a pointer to the sbuf data.
522  */
523 char *
524 sbuf_data(struct sbuf *s)
525 {
526 	assert_sbuf_integrity(s);
527 	assert_sbuf_state(s, SBUF_FINISHED);
528 
529 	return s->s_buf;
530 }
531 
532 /*
533  * Return the length of the sbuf data.
534  */
535 int
536 sbuf_len(struct sbuf *s)
537 {
538 	assert_sbuf_integrity(s);
539 	/* don't care if it's finished or not */
540 
541 	if (SBUF_HASOVERFLOWED(s))
542 		return (-1);
543 	return s->s_len;
544 }
545 
546 /*
547  * Clear an sbuf, free its buffer if necessary.
548  */
549 void
550 sbuf_delete(struct sbuf *s)
551 {
552 	int isdyn;
553 
554 	assert_sbuf_integrity(s);
555 	/* don't care if it's finished or not */
556 
557 	if (SBUF_ISDYNAMIC(s))
558 		SBFREE(s->s_buf);
559 	isdyn = SBUF_ISDYNSTRUCT(s);
560 	bzero(s, sizeof *s);
561 	if (isdyn)
562 		SBFREE(s);
563 }
564 
565 /*
566  * Check if an sbuf has been finished.
567  */
568 int
569 sbuf_done(struct sbuf *s)
570 {
571 	return(SBUF_ISFINISHED(s));
572 }
573