subr_sbuf.c revision 84097 
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: head/sys/kern/subr_sbuf.c 84097 2001-09-29 00:32:46Z des $
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 <stdlib.h>
44#endif /* _KERNEL */
45
46#include <sys/sbuf.h>
47
48#ifdef _KERNEL
49MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
50#define SBMALLOC(size)		malloc(size, M_SBUF, M_WAITOK)
51#define SBFREE(buf)		free(buf, M_SBUF)
52#else /* _KERNEL */
53#define KASSERT(e, m)
54#define SBMALLOC(size)		malloc(size)
55#define SBFREE(buf)		free(buf)
56#define min(x,y)		MIN(x,y)
57#endif /* _KERNEL */
58
59/*
60 * Predicates
61 */
62#define SBUF_ISDYNAMIC(s)	((s)->s_flags & SBUF_DYNAMIC)
63#define SBUF_ISDYNSTRUCT(s)	((s)->s_flags & SBUF_DYNSTRUCT)
64#define SBUF_ISFINISHED(s)	((s)->s_flags & SBUF_FINISHED)
65#define SBUF_HASOVERFLOWED(s)	((s)->s_flags & SBUF_OVERFLOWED)
66#define SBUF_HASROOM(s)		((s)->s_len < (s)->s_size - 1)
67
68/*
69 * Set / clear flags
70 */
71#define SBUF_SETFLAG(s, f)	do { (s)->s_flags |= (f); } while (0)
72#define SBUF_CLEARFLAG(s, f)	do { (s)->s_flags &= ~(f); } while (0)
73
74/*
75 * Debugging support
76 */
77#if defined(_KERNEL) && defined(INVARIANTS)
78static void
79_assert_sbuf_integrity(char *fun, struct sbuf *s)
80{
81	KASSERT(s != NULL,
82	    ("%s called with a NULL sbuf pointer", fun));
83	KASSERT(s->s_buf != NULL,
84	    ("%s called with unitialized or corrupt sbuf", fun));
85	KASSERT(s->s_len < s->s_size,
86	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
87}
88
89static void
90_assert_sbuf_state(char *fun, struct sbuf *s, int state)
91{
92	KASSERT((s->s_flags & SBUF_FINISHED) == state,
93	    ("%s called with %sfinished or corrupt sbuf", fun,
94	    (state ? "un" : "")));
95}
96#define assert_sbuf_integrity(s) _assert_sbuf_integrity(__FUNCTION__, (s))
97#define assert_sbuf_state(s, i)	 _assert_sbuf_state(__FUNCTION__, (s), (i))
98#else /* _KERNEL && INVARIANTS */
99#define assert_sbuf_integrity(s) do { } while (0)
100#define assert_sbuf_state(s, i)	 do { } while (0)
101#endif /* _KERNEL && INVARIANTS */
102
103/*
104 * Initialize an sbuf.
105 * If buf is non-NULL, it points to a static or already-allocated string
106 * big enough to hold at least length characters.
107 */
108struct sbuf *
109sbuf_new(struct sbuf *s, char *buf, int length, int flags)
110{
111	KASSERT(length >= 0,
112	    ("attempt to create an sbuf of negative length (%d)", length));
113	KASSERT(flags == 0,
114	    (__FUNCTION__ " called with non-zero flags"));
115
116	if (s == NULL) {
117		s = (struct sbuf *)SBMALLOC(sizeof *s);
118		if (s == NULL)
119			return (NULL);
120		bzero(s, sizeof *s);
121		SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
122	} else {
123		bzero(s, sizeof *s);
124	}
125	s->s_size = length;
126	if (buf) {
127		s->s_buf = buf;
128		return (s);
129	}
130	s->s_buf = (char *)SBMALLOC(s->s_size);
131	if (s->s_buf == NULL) {
132		if (SBUF_ISDYNSTRUCT(s))
133			SBFREE(s);
134		return (NULL);
135	}
136	SBUF_SETFLAG(s, SBUF_DYNAMIC);
137	return (s);
138}
139
140#ifdef _KERNEL
141/*
142 * Create an sbuf with uio data
143 */
144struct sbuf *
145sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
146{
147	KASSERT(uio != NULL,
148	    (__FUNCTION__ " called with NULL uio pointer"));
149	KASSERT(error != NULL,
150	    (__FUNCTION__ " called with NULL error pointer"));
151
152	s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
153	if (s == NULL) {
154		*error = ENOMEM;
155		return (NULL);
156	}
157	*error = uiomove(s->s_buf, uio->uio_resid, uio);
158	if (*error != 0) {
159		sbuf_delete(s);
160		return (NULL);
161	}
162	s->s_len = s->s_size - 1;
163	*error = 0;
164	return (s);
165}
166#endif
167
168/*
169 * Clear an sbuf and reset its position
170 */
171void
172sbuf_clear(struct sbuf *s)
173{
174	assert_sbuf_integrity(s);
175	/* don't care if it's finished or not */
176
177	SBUF_CLEARFLAG(s, SBUF_FINISHED);
178	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
179	s->s_len = 0;
180}
181
182/*
183 * Set the sbuf's position to an arbitrary value
184 */
185int
186sbuf_setpos(struct sbuf *s, int pos)
187{
188	assert_sbuf_integrity(s);
189	assert_sbuf_state(s, 0);
190
191	KASSERT(pos >= 0,
192	    ("attempt to seek to a negative position (%d)", pos));
193	KASSERT(pos < s->s_size,
194	    ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));
195
196	if (pos < 0 || pos > s->s_len)
197		return (-1);
198	s->s_len = pos;
199	return (0);
200}
201
202/*
203 * Append a byte string to an sbuf.
204 */
205int
206sbuf_bcat(struct sbuf *s, const char *str, size_t len)
207{
208	assert_sbuf_integrity(s);
209	assert_sbuf_state(s, 0);
210
211	if (SBUF_HASOVERFLOWED(s))
212		return (-1);
213
214	while (len-- && SBUF_HASROOM(s))
215		s->s_buf[s->s_len++] = *str++;
216	if (len) {
217		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
218		return (-1);
219	}
220	return (0);
221}
222
223#ifdef _KERNEL
224/*
225 * Copy a byte string from userland into an sbuf.
226 */
227int
228sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
229{
230	assert_sbuf_integrity(s);
231	assert_sbuf_state(s, 0);
232
233	if (SBUF_HASOVERFLOWED(s))
234		return (-1);
235
236	if (len == 0)
237		return (0);
238	if (len > (s->s_size - s->s_len - 1))
239		len = s->s_size - s->s_len - 1;
240	if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
241		return (-1);
242	s->s_len += len;
243
244	return (0);
245}
246#endif
247
248/*
249 * Copy a byte string into an sbuf.
250 */
251int
252sbuf_bcpy(struct sbuf *s, const char *str, size_t len)
253{
254	assert_sbuf_integrity(s);
255	assert_sbuf_state(s, 0);
256
257	sbuf_clear(s);
258	return (sbuf_bcat(s, str, len));
259}
260
261/*
262 * Append a string to an sbuf.
263 */
264int
265sbuf_cat(struct sbuf *s, const char *str)
266{
267	assert_sbuf_integrity(s);
268	assert_sbuf_state(s, 0);
269
270	if (SBUF_HASOVERFLOWED(s))
271		return (-1);
272
273	while (*str && SBUF_HASROOM(s))
274		s->s_buf[s->s_len++] = *str++;
275	if (*str) {
276		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
277		return (-1);
278	}
279	return (0);
280}
281
282#ifdef _KERNEL
283/*
284 * Copy a string from userland into an sbuf.
285 */
286int
287sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
288{
289	size_t done;
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 || len > (s->s_size - s->s_len - 1))
298		len = s->s_size - s->s_len - 1;
299	switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
300	case ENAMETOOLONG:
301		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
302		/* fall through */
303	case 0:
304		s->s_len += done - 1;
305		break;
306	default:
307		return (-1);	/* XXX */
308	}
309
310	return (0);
311}
312#endif
313
314/*
315 * Copy a string into an sbuf.
316 */
317int
318sbuf_cpy(struct sbuf *s, const char *str)
319{
320	assert_sbuf_integrity(s);
321	assert_sbuf_state(s, 0);
322
323	sbuf_clear(s);
324	return (sbuf_cat(s, str));
325}
326
327/*
328 * Format the given arguments and append the resulting string to an sbuf.
329 */
330int
331sbuf_printf(struct sbuf *s, const char *fmt, ...)
332{
333	va_list ap;
334	int len;
335
336	assert_sbuf_integrity(s);
337	assert_sbuf_state(s, 0);
338
339	KASSERT(fmt != NULL,
340	    (__FUNCTION__ " called with a NULL format string"));
341
342	if (SBUF_HASOVERFLOWED(s))
343		return (-1);
344
345	va_start(ap, fmt);
346	len = vsnprintf(&s->s_buf[s->s_len], s->s_size - s->s_len, fmt, ap);
347	va_end(ap);
348
349	/*
350	 * s->s_len is the length of the string, without the terminating nul.
351	 * When updating s->s_len, we must subtract 1 from the length that
352	 * we passed into vsnprintf() because that length includes the
353	 * terminating nul.
354	 *
355	 * vsnprintf() returns the amount that would have been copied,
356	 * given sufficient space, hence the min() calculation below.
357	 */
358	s->s_len += min(len, s->s_size - s->s_len - 1);
359	if (!SBUF_HASROOM(s))
360		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
361
362	KASSERT(s->s_len < s->s_size,
363	    ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
364
365	if (SBUF_HASOVERFLOWED(s))
366		return (-1);
367	return (0);
368}
369
370/*
371 * Append a character to an sbuf.
372 */
373int
374sbuf_putc(struct sbuf *s, int c)
375{
376	assert_sbuf_integrity(s);
377	assert_sbuf_state(s, 0);
378
379	if (SBUF_HASOVERFLOWED(s))
380		return (-1);
381
382	if (!SBUF_HASROOM(s)) {
383		SBUF_SETFLAG(s, SBUF_OVERFLOWED);
384		return (-1);
385	}
386	if (c != '\0')
387	    s->s_buf[s->s_len++] = c;
388	return (0);
389}
390
391/*
392 * Trim whitespace characters from an sbuf.
393 */
394int
395sbuf_trim(struct sbuf *s)
396{
397	assert_sbuf_integrity(s);
398	assert_sbuf_state(s, 0);
399
400	if (SBUF_HASOVERFLOWED(s))
401		return (-1);
402
403	while (s->s_len && isspace(s->s_buf[s->s_len-1]))
404		--s->s_len;
405
406	return (0);
407}
408
409/*
410 * Check if an sbuf overflowed
411 */
412int
413sbuf_overflowed(struct sbuf *s)
414{
415    return SBUF_HASOVERFLOWED(s);
416}
417
418/*
419 * Finish off an sbuf.
420 */
421void
422sbuf_finish(struct sbuf *s)
423{
424	assert_sbuf_integrity(s);
425	assert_sbuf_state(s, 0);
426
427	s->s_buf[s->s_len] = '\0';
428	SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
429	SBUF_SETFLAG(s, SBUF_FINISHED);
430}
431
432/*
433 * Return a pointer to the sbuf data.
434 */
435char *
436sbuf_data(struct sbuf *s)
437{
438	assert_sbuf_integrity(s);
439	assert_sbuf_state(s, SBUF_FINISHED);
440
441	return s->s_buf;
442}
443
444/*
445 * Return the length of the sbuf data.
446 */
447int
448sbuf_len(struct sbuf *s)
449{
450	assert_sbuf_integrity(s);
451	/* don't care if it's finished or not */
452
453	if (SBUF_HASOVERFLOWED(s))
454		return (-1);
455	return s->s_len;
456}
457
458/*
459 * Clear an sbuf, free its buffer if necessary.
460 */
461void
462sbuf_delete(struct sbuf *s)
463{
464	assert_sbuf_integrity(s);
465	/* don't care if it's finished or not */
466
467	if (SBUF_ISDYNAMIC(s))
468		SBFREE(s->s_buf);
469	bzero(s, sizeof *s);
470	if (SBUF_ISDYNSTRUCT(s))
471		SBFREE(s);
472}
473