subr_sbuf.c revision 181462 
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 181462 2008-08-09 10:26:21Z des $");
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
52static 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
88static void
89_assert_sbuf_integrity(const char *fun, struct sbuf *s)
90{
91
92	KASSERT(s != NULL,
93	    ("%s called with a NULL sbuf pointer", fun));
94	KASSERT(s->s_buf != NULL,
95	    ("%s called with uninitialized or corrupt sbuf", fun));
96	KASSERT(s->s_len < s->s_size,
97	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
98}
99
100static void
101_assert_sbuf_state(const char *fun, struct sbuf *s, int state)
102{
103
104	KASSERT((s->s_flags & SBUF_FINISHED) == state,
105	    ("%s called with %sfinished or corrupt sbuf", fun,
106	    (state ? "un" : "")));
107}
108
109#define	assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
110#define	assert_sbuf_state(s, i)	 _assert_sbuf_state(__func__, (s), (i))
111
112#else /* _KERNEL && INVARIANTS */
113
114#define	assert_sbuf_integrity(s) do { } while (0)
115#define	assert_sbuf_state(s, i)	 do { } while (0)
116
117#endif /* _KERNEL && INVARIANTS */
118
119static int
120sbuf_extendsize(int size)
121{
122	int newsize;
123
124	newsize = SBUF_MINEXTENDSIZE;
125	while (newsize < size) {
126		if (newsize < (int)SBUF_MAXEXTENDSIZE)
127			newsize *= 2;
128		else
129			newsize += SBUF_MAXEXTENDINCR;
130	}
131	return (newsize);
132}
133
134
135/*
136 * Extend an sbuf.
137 */
138static int
139sbuf_extend(struct sbuf *s, int addlen)
140{
141	char *newbuf;
142	int newsize;
143
144	if (!SBUF_CANEXTEND(s))
145		return (-1);
146	newsize = sbuf_extendsize(s->s_size + addlen);
147	newbuf = SBMALLOC(newsize);
148	if (newbuf == NULL)
149		return (-1);
150	bcopy(s->s_buf, newbuf, s->s_size);
151	if (SBUF_ISDYNAMIC(s))
152		SBFREE(s->s_buf);
153	else
154		SBUF_SETFLAG(s, SBUF_DYNAMIC);
155	s->s_buf = newbuf;
156	s->s_size = newsize;
157	return (0);
158}
159
160/*
161 * Initialize an sbuf.
162 * If buf is non-NULL, it points to a static or already-allocated string
163 * big enough to hold at least length characters.
164 */
165struct sbuf *
166sbuf_new(struct sbuf *s, char *buf, int length, int flags)
167{
168
169	KASSERT(length >= 0,
170	    ("attempt to create an sbuf of negative length (%d)", length));
171	KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
172	    ("%s called with invalid flags", __func__));
173
174	flags &= SBUF_USRFLAGMSK;
175	if (s == NULL) {
176		s = SBMALLOC(sizeof(*s));
177		if (s == NULL)
178			return (NULL);
179		bzero(s, sizeof(*s));
180		s->s_flags = flags;
181		SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
182	} else {
183		bzero(s, sizeof(*s));
184		s->s_flags = flags;
185	}
186	s->s_size = length;
187	if (buf) {
188		s->s_buf = buf;
189		return (s);
190	}
191	if (flags & SBUF_AUTOEXTEND)
192		s->s_size = sbuf_extendsize(s->s_size);
193	s->s_buf = SBMALLOC(s->s_size);
194	if (s->s_buf == NULL) {
195		if (SBUF_ISDYNSTRUCT(s))
196			SBFREE(s);
197		return (NULL);
198	}
199	SBUF_SETFLAG(s, SBUF_DYNAMIC);
200	return (s);
201}
202
203#ifdef _KERNEL
204/*
205 * Create an sbuf with uio data
206 */
207struct sbuf *
208sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
209{
210
211	KASSERT(uio != NULL,
212	    ("%s called with NULL uio pointer", __func__));
213	KASSERT(error != NULL,
214	    ("%s called with NULL error pointer", __func__));
215
216	s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
217	if (s == NULL) {
218		*error = ENOMEM;
219		return (NULL);
220	}
221	*error = uiomove(s->s_buf, uio->uio_resid, uio);
222	if (*error != 0) {
223		sbuf_delete(s);
224		return (NULL);
225	}
226	s->s_len = s->s_size - 1;
227	*error = 0;
228	return (s);
229}
230#endif
231
232/*
233 * Clear an sbuf and reset its position.
234 */
235void
236sbuf_clear(struct sbuf *s)
237{
238
239	assert_sbuf_integrity(s);
240	/* don't care if it's finished or not */
241
242	SBUF_CLEARFLAG(s, SBUF_FINISHED);
243	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
244	s->s_len = 0;
245}
246
247/*
248 * Set the sbuf's end position to an arbitrary value.
249 * Effectively truncates the sbuf at the new position.
250 */
251int
252sbuf_setpos(struct sbuf *s, int pos)
253{
254
255	assert_sbuf_integrity(s);
256	assert_sbuf_state(s, 0);
257
258	KASSERT(pos >= 0,
259	    ("attempt to seek to a negative position (%d)", pos));
260	KASSERT(pos < s->s_size,
261	    ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));
262
263	if (pos < 0 || pos > s->s_len)
264		return (-1);
265	s->s_len = pos;
266	return (0);
267}
268
269/*
270 * Append a byte string to an sbuf.
271 */
272int
273sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
274{
275	const char *str = buf;
276
277	assert_sbuf_integrity(s);
278	assert_sbuf_state(s, 0);
279
280	if (SBUF_HASOVERFLOWED(s))
281		return (-1);
282	for (; len; len--) {
283		if (!SBUF_HASROOM(s) && sbuf_extend(s, len) < 0)
284			break;
285		s->s_buf[s->s_len++] = *str++;
286	}
287	if (len) {
288		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
289		return (-1);
290	}
291	return (0);
292}
293
294#ifdef _KERNEL
295/*
296 * Copy a byte string from userland into an sbuf.
297 */
298int
299sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
300{
301
302	assert_sbuf_integrity(s);
303	assert_sbuf_state(s, 0);
304
305	if (SBUF_HASOVERFLOWED(s))
306		return (-1);
307	if (len == 0)
308		return (0);
309	if (len > SBUF_FREESPACE(s)) {
310		sbuf_extend(s, len - SBUF_FREESPACE(s));
311		len = min(len, SBUF_FREESPACE(s));
312	}
313	if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
314		return (-1);
315	s->s_len += len;
316
317	return (0);
318}
319#endif
320
321/*
322 * Copy a byte string into an sbuf.
323 */
324int
325sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
326{
327
328	assert_sbuf_integrity(s);
329	assert_sbuf_state(s, 0);
330
331	sbuf_clear(s);
332	return (sbuf_bcat(s, buf, len));
333}
334
335/*
336 * Append a string to an sbuf.
337 */
338int
339sbuf_cat(struct sbuf *s, const char *str)
340{
341
342	assert_sbuf_integrity(s);
343	assert_sbuf_state(s, 0);
344
345	if (SBUF_HASOVERFLOWED(s))
346		return (-1);
347
348	while (*str) {
349		if (!SBUF_HASROOM(s) && sbuf_extend(s, strlen(str)) < 0)
350			break;
351		s->s_buf[s->s_len++] = *str++;
352	}
353	if (*str) {
354		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
355		return (-1);
356	}
357	return (0);
358}
359
360#ifdef _KERNEL
361/*
362 * Append a string from userland to an sbuf.
363 */
364int
365sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
366{
367	size_t done;
368
369	assert_sbuf_integrity(s);
370	assert_sbuf_state(s, 0);
371
372	if (SBUF_HASOVERFLOWED(s))
373		return (-1);
374
375	if (len == 0)
376		len = SBUF_FREESPACE(s);	/* XXX return 0? */
377	if (len > SBUF_FREESPACE(s)) {
378		sbuf_extend(s, len);
379		len = min(len, SBUF_FREESPACE(s));
380	}
381	switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
382	case ENAMETOOLONG:
383		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
384		/* fall through */
385	case 0:
386		s->s_len += done - 1;
387		break;
388	default:
389		return (-1);	/* XXX */
390	}
391
392	return (done);
393}
394#endif
395
396/*
397 * Copy a string into an sbuf.
398 */
399int
400sbuf_cpy(struct sbuf *s, const char *str)
401{
402
403	assert_sbuf_integrity(s);
404	assert_sbuf_state(s, 0);
405
406	sbuf_clear(s);
407	return (sbuf_cat(s, str));
408}
409
410/*
411 * Format the given argument list and append the resulting string to an sbuf.
412 */
413int
414sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
415{
416	va_list ap_copy;
417	int len;
418
419	assert_sbuf_integrity(s);
420	assert_sbuf_state(s, 0);
421
422	KASSERT(fmt != NULL,
423	    ("%s called with a NULL format string", __func__));
424
425	if (SBUF_HASOVERFLOWED(s))
426		return (-1);
427
428	do {
429		va_copy(ap_copy, ap);
430		len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
431		    fmt, ap_copy);
432		va_end(ap_copy);
433	} while (len > SBUF_FREESPACE(s) &&
434	    sbuf_extend(s, len - SBUF_FREESPACE(s)) == 0);
435
436	/*
437	 * s->s_len is the length of the string, without the terminating nul.
438	 * When updating s->s_len, we must subtract 1 from the length that
439	 * we passed into vsnprintf() because that length includes the
440	 * terminating nul.
441	 *
442	 * vsnprintf() returns the amount that would have been copied,
443	 * given sufficient space, hence the min() calculation below.
444	 */
445	s->s_len += min(len, SBUF_FREESPACE(s));
446	if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
447		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
448
449	KASSERT(s->s_len < s->s_size,
450	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
451
452	if (SBUF_HASOVERFLOWED(s))
453		return (-1);
454	return (0);
455}
456
457/*
458 * Format the given arguments and append the resulting string to an sbuf.
459 */
460int
461sbuf_printf(struct sbuf *s, const char *fmt, ...)
462{
463	va_list ap;
464	int result;
465
466	va_start(ap, fmt);
467	result = sbuf_vprintf(s, fmt, ap);
468	va_end(ap);
469	return (result);
470}
471
472/*
473 * Append a character to an sbuf.
474 */
475int
476sbuf_putc(struct sbuf *s, int c)
477{
478
479	assert_sbuf_integrity(s);
480	assert_sbuf_state(s, 0);
481
482	if (SBUF_HASOVERFLOWED(s))
483		return (-1);
484	if (!SBUF_HASROOM(s) && sbuf_extend(s, 1) < 0) {
485		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
486		return (-1);
487	}
488	if (c != '\0')
489	    s->s_buf[s->s_len++] = c;
490	return (0);
491}
492
493/*
494 * Trim whitespace characters from end of an sbuf.
495 */
496int
497sbuf_trim(struct sbuf *s)
498{
499
500	assert_sbuf_integrity(s);
501	assert_sbuf_state(s, 0);
502
503	if (SBUF_HASOVERFLOWED(s))
504		return (-1);
505
506	while (s->s_len && isspace(s->s_buf[s->s_len-1]))
507		--s->s_len;
508
509	return (0);
510}
511
512/*
513 * Check if an sbuf overflowed
514 */
515int
516sbuf_overflowed(struct sbuf *s)
517{
518
519	return (SBUF_HASOVERFLOWED(s));
520}
521
522/*
523 * Finish off an sbuf.
524 */
525void
526sbuf_finish(struct sbuf *s)
527{
528
529	assert_sbuf_integrity(s);
530	assert_sbuf_state(s, 0);
531
532	s->s_buf[s->s_len] = '\0';
533	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
534	SBUF_SETFLAG(s, SBUF_FINISHED);
535}
536
537/*
538 * Return a pointer to the sbuf data.
539 */
540char *
541sbuf_data(struct sbuf *s)
542{
543
544	assert_sbuf_integrity(s);
545	assert_sbuf_state(s, SBUF_FINISHED);
546
547	return (s->s_buf);
548}
549
550/*
551 * Return the length of the sbuf data.
552 */
553int
554sbuf_len(struct sbuf *s)
555{
556
557	assert_sbuf_integrity(s);
558	/* don't care if it's finished or not */
559
560	if (SBUF_HASOVERFLOWED(s))
561		return (-1);
562	return (s->s_len);
563}
564
565/*
566 * Clear an sbuf, free its buffer if necessary.
567 */
568void
569sbuf_delete(struct sbuf *s)
570{
571	int isdyn;
572
573	assert_sbuf_integrity(s);
574	/* don't care if it's finished or not */
575
576	if (SBUF_ISDYNAMIC(s))
577		SBFREE(s->s_buf);
578	isdyn = SBUF_ISDYNSTRUCT(s);
579	bzero(s, sizeof(*s));
580	if (isdyn)
581		SBFREE(s);
582}
583
584/*
585 * Check if an sbuf has been finished.
586 */
587int
588sbuf_done(struct sbuf *s)
589{
590
591	return (SBUF_ISFINISHED(s));
592}
593