subr_sbuf.c revision 153678 
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
29#include <sys/cdefs.h>
30__FBSDID("$FreeBSD: head/sys/kern/subr_sbuf.c 153678 2005-12-23 11:49:53Z phk $");
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)
87static 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
98static 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
112static int
113sbuf_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 */
132static int
133sbuf_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 */
160struct sbuf *
161sbuf_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 */
201struct sbuf *
202sbuf_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 */
228void
229sbuf_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 */
243int
244sbuf_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 */
263int
264sbuf_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 */
290int
291sbuf_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 */
316int
317sbuf_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 */
329int
330sbuf_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 */
354int
355sbuf_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 (done);
383}
384#endif
385
386/*
387 * Copy a string into an sbuf.
388 */
389int
390sbuf_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 */
402int
403sbuf_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 */
449int
450sbuf_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 */
464int
465sbuf_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 */
485int
486sbuf_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 */
503int
504sbuf_overflowed(struct sbuf *s)
505{
506    return SBUF_HASOVERFLOWED(s);
507}
508
509/*
510 * Finish off an sbuf.
511 */
512void
513sbuf_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 */
526char *
527sbuf_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 */
538int
539sbuf_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 */
552void
553sbuf_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 */
571int
572sbuf_done(struct sbuf *s)
573{
574
575	return(SBUF_ISFINISHED(s));
576}
577