2 * Copyright (c) 2000-2008 Poul-Henning Kamp
3 * Copyright (c) 2000-2008 Dag-Erling Coïdan Smørgrav
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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.
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
28 * $FreeBSD: head/sys/kern/subr_sbuf.c 255805 2013-09-22 23:47:56Z des $
31 #include <sys/param.h>
32 #include <sys/errno.h>
35 #include <sys/ctype.h>
36 #include <sys/kernel.h>
37 #include <sys/malloc.h>
38 #include <sys/systm.h>
40 #include <machine/stdarg.h>
52 static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
53 #define SBMALLOC(size) kmalloc(size, M_SBUF, M_WAITOK|M_ZERO)
54 #define SBFREE(buf) kfree(buf, M_SBUF)
57 #define SBMALLOC(size) calloc(1, size)
58 #define SBFREE(buf) free(buf)
59 #define kvsnprintf vsnprintf
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_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 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
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)
79 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
82 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
83 #define SBUF_MAXEXTENDINCR PAGE_SIZE
85 #define SBUF_MAXEXTENDSIZE 4096
86 #define SBUF_MAXEXTENDINCR 4096
92 #if defined(_KERNEL) && defined(INVARIANTS)
95 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
99 ("%s called with a NULL sbuf pointer", fun));
100 KASSERT(s->s_buf != NULL,
101 ("%s called with uninitialized or corrupt sbuf", fun));
102 KASSERT(s->s_len < s->s_size,
103 ("wrote past end of sbuf (%jd >= %jd)",
104 (intmax_t)s->s_len, (intmax_t)s->s_size));
108 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
111 KASSERT((s->s_flags & SBUF_FINISHED) == state,
112 ("%s called with %sfinished or corrupt sbuf", fun,
113 (state ? "un" : "")));
116 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
117 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
119 #else /* _KERNEL && INVARIANTS */
121 #define assert_sbuf_integrity(s) do { } while (0)
122 #define assert_sbuf_state(s, i) do { } while (0)
124 #endif /* _KERNEL && INVARIANTS */
127 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
128 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
132 sbuf_extendsize(int size)
136 if (size < (int)SBUF_MAXEXTENDSIZE) {
137 newsize = SBUF_MINEXTENDSIZE;
138 while (newsize < size)
141 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
143 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
151 sbuf_extend(struct sbuf *s, int addlen)
156 if (!SBUF_CANEXTEND(s))
158 newsize = sbuf_extendsize(s->s_size + addlen);
159 newbuf = SBMALLOC(newsize);
162 memcpy(newbuf, s->s_buf, s->s_size);
163 if (SBUF_ISDYNAMIC(s))
166 SBUF_SETFLAG(s, SBUF_DYNAMIC);
173 * Initialize the internals of an sbuf.
174 * If buf is non-NULL, it points to a static or already-allocated string
175 * big enough to hold at least length characters.
178 sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags)
181 memset(s, 0, sizeof(*s));
186 if ((s->s_flags & SBUF_AUTOEXTEND) == 0) {
187 KASSERT(s->s_size >= 0,
188 ("attempt to create a too small sbuf"));
191 if (s->s_buf != NULL)
194 if ((flags & SBUF_AUTOEXTEND) != 0)
195 s->s_size = sbuf_extendsize(s->s_size);
197 s->s_buf = SBMALLOC(s->s_size);
198 if (s->s_buf == NULL)
200 SBUF_SETFLAG(s, SBUF_DYNAMIC);
205 * Initialize an sbuf.
206 * If buf is non-NULL, it points to a static or already-allocated string
207 * big enough to hold at least length characters.
210 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
214 ("attempt to create an sbuf of negative length (%d)", length));
215 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
216 ("%s called with invalid flags", __func__));
218 flags &= SBUF_USRFLAGMSK;
220 return (sbuf_newbuf(s, buf, length, flags));
222 s = SBMALLOC(sizeof(*s));
225 if (sbuf_newbuf(s, buf, length, flags) == NULL) {
229 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
235 * Create an sbuf with uio data
238 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
242 ("%s called with NULL uio pointer", __func__));
243 KASSERT(error != NULL,
244 ("%s called with NULL error pointer", __func__));
246 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
251 *error = uiomove(s->s_buf, uio->uio_resid, uio);
256 s->s_len = s->s_size - 1;
257 if (SBUF_ISSECTION(s))
258 s->s_sect_len = s->s_size - 1;
265 * Clear an sbuf and reset its position.
268 sbuf_clear(struct sbuf *s)
271 assert_sbuf_integrity(s);
272 /* don't care if it's finished or not */
274 SBUF_CLEARFLAG(s, SBUF_FINISHED);
281 * Set the sbuf's end position to an arbitrary value.
282 * Effectively truncates the sbuf at the new position.
285 sbuf_setpos(struct sbuf *s, ssize_t pos)
288 assert_sbuf_integrity(s);
289 assert_sbuf_state(s, 0);
292 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
293 KASSERT(pos < s->s_size,
294 ("attempt to seek past end of sbuf (%jd >= %jd)",
295 (intmax_t)pos, (intmax_t)s->s_size));
296 KASSERT(!SBUF_ISSECTION(s),
297 ("attempt to seek when in a section"));
299 if (pos < 0 || pos > s->s_len)
306 * Set up a drain function and argument on an sbuf to flush data to
307 * when the sbuf buffer overflows.
310 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
313 assert_sbuf_state(s, 0);
314 assert_sbuf_integrity(s);
315 KASSERT(func == s->s_drain_func || s->s_len == 0,
316 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
317 s->s_drain_func = func;
318 s->s_drain_arg = ctx;
322 * Call the drain and process the return.
325 sbuf_drain(struct sbuf *s)
329 KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
330 KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
331 len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len);
336 KASSERT(len > 0 && len <= s->s_len,
337 ("Bad drain amount %d for sbuf %p", len, s));
340 * Fast path for the expected case where all the data was
346 * Move the remaining characters to the beginning of the
349 memmove(s->s_buf, s->s_buf + len, s->s_len);
354 * Append a byte to an sbuf. This is the core function for appending
355 * to an sbuf and is the main place that deals with extending the
356 * buffer and marking overflow.
359 sbuf_put_byte(struct sbuf *s, int c)
362 assert_sbuf_integrity(s);
363 assert_sbuf_state(s, 0);
367 if (SBUF_FREESPACE(s) <= 0) {
369 * If there is a drain, use it, otherwise extend the
372 if (s->s_drain_func != NULL)
374 else if (sbuf_extend(s, 1) < 0)
379 s->s_buf[s->s_len++] = c;
380 if (SBUF_ISSECTION(s))
385 * Append a byte string to an sbuf.
388 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
390 const char *str = buf;
391 const char *end = str + len;
393 assert_sbuf_integrity(s);
394 assert_sbuf_state(s, 0);
398 for (; str < end; str++) {
399 sbuf_put_byte(s, *str);
408 * Copy a byte string from userland into an sbuf.
411 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
414 assert_sbuf_integrity(s);
415 assert_sbuf_state(s, 0);
416 KASSERT(s->s_drain_func == NULL,
417 ("Nonsensical copyin to sbuf %p with a drain", s));
423 if (len > SBUF_FREESPACE(s)) {
424 sbuf_extend(s, len - SBUF_FREESPACE(s));
425 if (SBUF_FREESPACE(s) < len)
426 len = SBUF_FREESPACE(s);
428 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
437 * Copy a byte string into an sbuf.
440 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
443 assert_sbuf_integrity(s);
444 assert_sbuf_state(s, 0);
447 return (sbuf_bcat(s, buf, len));
451 * Append a string to an sbuf.
454 sbuf_cat(struct sbuf *s, const char *str)
457 assert_sbuf_integrity(s);
458 assert_sbuf_state(s, 0);
463 while (*str != '\0') {
464 sbuf_put_byte(s, *str++);
473 * Append a string from userland to an sbuf.
476 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
480 assert_sbuf_integrity(s);
481 assert_sbuf_state(s, 0);
482 KASSERT(s->s_drain_func == NULL,
483 ("Nonsensical copyin to sbuf %p with a drain", s));
489 len = SBUF_FREESPACE(s); /* XXX return 0? */
490 if (len > SBUF_FREESPACE(s)) {
492 if (SBUF_FREESPACE(s) < len)
493 len = SBUF_FREESPACE(s);
495 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
500 s->s_len += done - 1;
501 if (SBUF_ISSECTION(s))
502 s->s_sect_len += done - 1;
505 return (-1); /* XXX */
513 * Copy a string into an sbuf.
516 sbuf_cpy(struct sbuf *s, const char *str)
519 assert_sbuf_integrity(s);
520 assert_sbuf_state(s, 0);
523 return (sbuf_cat(s, str));
527 * Format the given argument list and append the resulting string to an sbuf.
532 * Append a non-NUL character to an sbuf. This prototype signature is
533 * suitable for use with kvcprintf(9).
536 sbuf_putc_func(int c, void *arg)
540 sbuf_put_byte(arg, c);
544 sbuf_vprintf(struct sbuf *s, const char *fmt, __va_list ap)
547 assert_sbuf_integrity(s);
548 assert_sbuf_state(s, 0);
551 ("%s called with a NULL format string", __func__));
553 (void)kvcprintf(fmt, sbuf_putc_func, s, ap);
560 sbuf_vprintf(struct sbuf *s, const char *fmt, __va_list ap)
565 assert_sbuf_integrity(s);
566 assert_sbuf_state(s, 0);
569 ("%s called with a NULL format string", __func__));
575 * For the moment, there is no way to get vsnprintf(3) to hand
576 * back a character at a time, to push everything into
577 * sbuf_putc_func() as was done for the kernel.
579 * In userspace, while drains are useful, there's generally
580 * not a problem attempting to malloc(3) on out of space. So
581 * expand a userland sbuf if there is not enough room for the
582 * data produced by sbuf_[v]printf(3).
587 va_copy(ap_copy, ap);
588 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
592 if (SBUF_FREESPACE(s) >= len)
594 /* Cannot print with the current available space. */
595 if (s->s_drain_func != NULL && s->s_len > 0)
596 error = sbuf_drain(s);
598 error = sbuf_extend(s, len - SBUF_FREESPACE(s));
599 } while (error == 0);
602 * s->s_len is the length of the string, without the terminating nul.
603 * When updating s->s_len, we must subtract 1 from the length that
604 * we passed into vsnprintf() because that length includes the
607 * vsnprintf() returns the amount that would have been copied,
608 * given sufficient space, so don't over-increment s_len.
610 if (SBUF_FREESPACE(s) < len)
611 len = SBUF_FREESPACE(s);
613 if (SBUF_ISSECTION(s))
614 s->s_sect_len += len;
615 if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
618 KASSERT(s->s_len < s->s_size,
619 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
628 * Format the given arguments and append the resulting string to an sbuf.
631 sbuf_printf(struct sbuf *s, const char *fmt, ...)
637 result = sbuf_vprintf(s, fmt, ap);
643 * Append a character to an sbuf.
646 sbuf_putc(struct sbuf *s, int c)
656 * Trim whitespace characters from end of an sbuf.
659 sbuf_trim(struct sbuf *s)
662 assert_sbuf_integrity(s);
663 assert_sbuf_state(s, 0);
664 KASSERT(s->s_drain_func == NULL,
665 ("%s makes no sense on sbuf %p with drain", __func__, s));
670 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
672 if (SBUF_ISSECTION(s))
680 * Check if an sbuf has an error.
683 sbuf_error(const struct sbuf *s)
690 * Finish off an sbuf.
693 sbuf_finish(struct sbuf *s)
696 assert_sbuf_integrity(s);
697 assert_sbuf_state(s, 0);
699 if (s->s_drain_func != NULL) {
700 while (s->s_len > 0 && s->s_error == 0)
701 s->s_error = sbuf_drain(s);
703 s->s_buf[s->s_len] = '\0';
704 SBUF_SETFLAG(s, SBUF_FINISHED);
708 if (s->s_error != 0) {
717 * Return a pointer to the sbuf data.
720 sbuf_data(struct sbuf *s)
723 assert_sbuf_integrity(s);
724 assert_sbuf_state(s, SBUF_FINISHED);
725 KASSERT(s->s_drain_func == NULL,
726 ("%s makes no sense on sbuf %p with drain", __func__, s));
732 * Return the length of the sbuf data.
735 sbuf_len(struct sbuf *s)
738 assert_sbuf_integrity(s);
739 /* don't care if it's finished or not */
740 KASSERT(s->s_drain_func == NULL,
741 ("%s makes no sense on sbuf %p with drain", __func__, s));
749 * Clear an sbuf, free its buffer if necessary.
752 sbuf_delete(struct sbuf *s)
756 assert_sbuf_integrity(s);
757 /* don't care if it's finished or not */
759 if (SBUF_ISDYNAMIC(s))
761 isdyn = SBUF_ISDYNSTRUCT(s);
762 memset(s, 0, sizeof(*s));
768 * Check if an sbuf has been finished.
771 sbuf_done(const struct sbuf *s)
774 return (SBUF_ISFINISHED(s));
781 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
784 assert_sbuf_integrity(s);
785 assert_sbuf_state(s, 0);
787 if (!SBUF_ISSECTION(s)) {
788 KASSERT(s->s_sect_len == 0,
789 ("s_sect_len != 0 when starting a section"));
790 if (old_lenp != NULL)
792 SBUF_SETFLAG(s, SBUF_INSECTION);
794 KASSERT(old_lenp != NULL,
795 ("s_sect_len should be saved when starting a subsection"));
796 *old_lenp = s->s_sect_len;
802 * End the section padding to the specified length with the specified
806 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
810 assert_sbuf_integrity(s);
811 assert_sbuf_state(s, 0);
812 KASSERT(SBUF_ISSECTION(s),
813 ("attempt to end a section when not in a section"));
816 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
817 for (; s->s_error == 0 && len > 0; len--)
823 SBUF_CLEARFLAG(s, SBUF_INSECTION);
825 s->s_sect_len += old_len;