2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
4 * Copyright (c) 2000-2008 Poul-Henning Kamp
5 * Copyright (c) 2000-2008 Dag-Erling Coïdan Smørgrav
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer
13 * in this position and unchanged.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
34 #include <sys/param.h>
37 #include <sys/ctype.h>
38 #include <sys/errno.h>
39 #include <sys/kernel.h>
40 #include <sys/limits.h>
41 #include <sys/malloc.h>
42 #include <sys/systm.h>
44 #include <machine/stdarg.h>
58 static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
59 #define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK|M_ZERO)
60 #define SBFREE(buf) free(buf, M_SBUF)
63 #define SBMALLOC(size) calloc(1, size)
64 #define SBFREE(buf) free(buf)
70 #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC)
71 #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT)
72 #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED)
73 #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
74 #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
75 #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
76 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
77 #define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL)
78 #define SBUF_ISDRAINTOEOR(s) ((s)->s_flags & SBUF_DRAINTOEOR)
79 #define SBUF_DODRAINTOEOR(s) (SBUF_ISSECTION(s) && SBUF_ISDRAINTOEOR(s))
84 #define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
85 #define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
87 #define SBUF_MINSIZE 2 /* Min is 1 byte + nulterm. */
88 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
91 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
92 #define SBUF_MAXEXTENDINCR PAGE_SIZE
94 #define SBUF_MAXEXTENDSIZE 4096
95 #define SBUF_MAXEXTENDINCR 4096
101 #if defined(_KERNEL) && defined(INVARIANTS)
104 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
108 ("%s called with a NULL sbuf pointer", fun));
109 KASSERT(s->s_buf != NULL,
110 ("%s called with uninitialized or corrupt sbuf", fun));
111 if (SBUF_ISFINISHED(s) && SBUF_NULINCLUDED(s)) {
112 KASSERT(s->s_len <= s->s_size,
113 ("wrote past end of sbuf (%jd >= %jd)",
114 (intmax_t)s->s_len, (intmax_t)s->s_size));
116 KASSERT(s->s_len < s->s_size,
117 ("wrote past end of sbuf (%jd >= %jd)",
118 (intmax_t)s->s_len, (intmax_t)s->s_size));
123 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
126 KASSERT((s->s_flags & SBUF_FINISHED) == state,
127 ("%s called with %sfinished or corrupt sbuf", fun,
128 (state ? "un" : "")));
131 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
132 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
134 #else /* _KERNEL && INVARIANTS */
136 #define assert_sbuf_integrity(s) do { } while (0)
137 #define assert_sbuf_state(s, i) do { } while (0)
139 #endif /* _KERNEL && INVARIANTS */
142 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
143 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
147 sbuf_extendsize(int size)
151 if (size < (int)SBUF_MAXEXTENDSIZE) {
152 newsize = SBUF_MINEXTENDSIZE;
153 while (newsize < size)
156 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
158 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
166 sbuf_extend(struct sbuf *s, int addlen)
171 if (!SBUF_CANEXTEND(s))
173 newsize = sbuf_extendsize(s->s_size + addlen);
174 newbuf = SBMALLOC(newsize);
177 memcpy(newbuf, s->s_buf, s->s_size);
178 if (SBUF_ISDYNAMIC(s))
181 SBUF_SETFLAG(s, SBUF_DYNAMIC);
188 * Initialize the internals of an sbuf.
189 * If buf is non-NULL, it points to a static or already-allocated string
190 * big enough to hold at least length characters.
193 sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags)
196 memset(s, 0, sizeof(*s));
201 if ((s->s_flags & SBUF_AUTOEXTEND) == 0) {
202 KASSERT(s->s_size >= SBUF_MINSIZE,
203 ("attempt to create an sbuf smaller than %d bytes",
207 if (s->s_buf != NULL)
210 if ((flags & SBUF_AUTOEXTEND) != 0)
211 s->s_size = sbuf_extendsize(s->s_size);
213 s->s_buf = SBMALLOC(s->s_size);
214 if (s->s_buf == NULL)
216 SBUF_SETFLAG(s, SBUF_DYNAMIC);
221 * Initialize an sbuf.
222 * If buf is non-NULL, it points to a static or already-allocated string
223 * big enough to hold at least length characters.
226 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
230 ("attempt to create an sbuf of negative length (%d)", length));
231 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
232 ("%s called with invalid flags", __func__));
234 flags &= SBUF_USRFLAGMSK;
236 return (sbuf_newbuf(s, buf, length, flags));
238 s = SBMALLOC(sizeof(*s));
241 if (sbuf_newbuf(s, buf, length, flags) == NULL) {
245 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
251 * Create an sbuf with uio data
254 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
258 ("%s called with NULL uio pointer", __func__));
259 KASSERT(error != NULL,
260 ("%s called with NULL error pointer", __func__));
262 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
267 *error = uiomove(s->s_buf, uio->uio_resid, uio);
272 s->s_len = s->s_size - 1;
273 if (SBUF_ISSECTION(s))
274 s->s_sect_len = s->s_size - 1;
281 sbuf_get_flags(struct sbuf *s)
284 return (s->s_flags & SBUF_USRFLAGMSK);
288 sbuf_clear_flags(struct sbuf *s, int flags)
291 s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
295 sbuf_set_flags(struct sbuf *s, int flags)
299 s->s_flags |= (flags & SBUF_USRFLAGMSK);
303 * Clear an sbuf and reset its position.
306 sbuf_clear(struct sbuf *s)
309 assert_sbuf_integrity(s);
310 /* don't care if it's finished or not */
312 SBUF_CLEARFLAG(s, SBUF_FINISHED);
320 * Set the sbuf's end position to an arbitrary value.
321 * Effectively truncates the sbuf at the new position.
324 sbuf_setpos(struct sbuf *s, ssize_t pos)
327 assert_sbuf_integrity(s);
328 assert_sbuf_state(s, 0);
331 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
332 KASSERT(pos < s->s_size,
333 ("attempt to seek past end of sbuf (%jd >= %jd)",
334 (intmax_t)pos, (intmax_t)s->s_size));
335 KASSERT(!SBUF_ISSECTION(s),
336 ("attempt to seek when in a section"));
338 if (pos < 0 || pos > s->s_len)
345 * Drain into a counter. Counts amount of data without producing output.
346 * Useful for cases like sysctl, where user may first request only size.
347 * This allows to avoid pointless allocation/freeing of large buffers.
350 sbuf_count_drain(void *arg, const char *data __unused, int len)
354 sizep = (size_t *)arg;
360 * Set up a drain function and argument on an sbuf to flush data to
361 * when the sbuf buffer overflows.
364 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
367 assert_sbuf_state(s, 0);
368 assert_sbuf_integrity(s);
369 KASSERT(func == s->s_drain_func || s->s_len == 0,
370 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
371 s->s_drain_func = func;
372 s->s_drain_arg = ctx;
376 * Call the drain and process the return.
379 sbuf_drain(struct sbuf *s)
384 * Immediately return when no work to do,
385 * or an error has already been accumulated.
387 if ((s->s_len == 0) || (s->s_error != 0))
390 if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
391 return (s->s_error = EDEADLK);
392 len = s->s_drain_func(s->s_drain_arg, s->s_buf,
393 SBUF_DODRAINTOEOR(s) ? s->s_rec_off : s->s_len);
395 s->s_error = len ? -len : EDEADLK;
398 KASSERT(len > 0 && len <= s->s_len,
399 ("Bad drain amount %d for sbuf %p", len, s));
403 * Fast path for the expected case where all the data was
409 * Move the remaining characters to the beginning of the
412 memmove(s->s_buf, s->s_buf + len, s->s_len);
417 * Append bytes to an sbuf. This is the core function for appending
418 * to an sbuf and is the main place that deals with extending the
419 * buffer and marking overflow.
422 sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
426 assert_sbuf_integrity(s);
427 assert_sbuf_state(s, 0);
432 if (SBUF_FREESPACE(s) <= 0) {
434 * If there is a drain, use it, otherwise extend the
437 if (s->s_drain_func != NULL)
439 else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
445 n = SBUF_FREESPACE(s);
448 memcpy(&s->s_buf[s->s_len], buf, n);
450 if (SBUF_ISSECTION(s))
458 sbuf_put_byte(struct sbuf *s, char c)
461 sbuf_put_bytes(s, &c, 1);
465 * Append a byte string to an sbuf.
468 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
471 sbuf_put_bytes(s, buf, len);
479 * Copy a byte string from userland into an sbuf.
482 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
485 assert_sbuf_integrity(s);
486 assert_sbuf_state(s, 0);
487 KASSERT(s->s_drain_func == NULL,
488 ("Nonsensical copyin to sbuf %p with a drain", s));
494 if (len > SBUF_FREESPACE(s)) {
495 sbuf_extend(s, len - SBUF_FREESPACE(s));
496 if (SBUF_FREESPACE(s) < len)
497 len = SBUF_FREESPACE(s);
499 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
508 * Copy a byte string into an sbuf.
511 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
514 assert_sbuf_integrity(s);
515 assert_sbuf_state(s, 0);
518 return (sbuf_bcat(s, buf, len));
522 * Append a string to an sbuf.
525 sbuf_cat(struct sbuf *s, const char *str)
530 sbuf_put_bytes(s, str, n);
538 * Append a string from userland to an sbuf.
541 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
545 assert_sbuf_integrity(s);
546 assert_sbuf_state(s, 0);
547 KASSERT(s->s_drain_func == NULL,
548 ("Nonsensical copyin to sbuf %p with a drain", s));
554 len = SBUF_FREESPACE(s); /* XXX return 0? */
555 if (len > SBUF_FREESPACE(s)) {
557 if (SBUF_FREESPACE(s) < len)
558 len = SBUF_FREESPACE(s);
560 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
565 s->s_len += done - 1;
566 if (SBUF_ISSECTION(s))
567 s->s_sect_len += done - 1;
570 return (-1); /* XXX */
578 * Copy a string into an sbuf.
581 sbuf_cpy(struct sbuf *s, const char *str)
584 assert_sbuf_integrity(s);
585 assert_sbuf_state(s, 0);
588 return (sbuf_cat(s, str));
592 * Format the given argument list and append the resulting string to an sbuf.
597 * Append a non-NUL character to an sbuf. This prototype signature is
598 * suitable for use with kvprintf(9).
601 sbuf_putc_func(int c, void *arg)
605 sbuf_put_byte(arg, c);
609 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
612 assert_sbuf_integrity(s);
613 assert_sbuf_state(s, 0);
616 ("%s called with a NULL format string", __func__));
618 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
625 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
630 assert_sbuf_integrity(s);
631 assert_sbuf_state(s, 0);
634 ("%s called with a NULL format string", __func__));
640 * For the moment, there is no way to get vsnprintf(3) to hand
641 * back a character at a time, to push everything into
642 * sbuf_putc_func() as was done for the kernel.
644 * In userspace, while drains are useful, there's generally
645 * not a problem attempting to malloc(3) on out of space. So
646 * expand a userland sbuf if there is not enough room for the
647 * data produced by sbuf_[v]printf(3).
652 va_copy(ap_copy, ap);
653 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
661 if (SBUF_FREESPACE(s) >= len)
663 /* Cannot print with the current available space. */
664 if (s->s_drain_func != NULL && s->s_len > 0)
665 error = sbuf_drain(s); /* sbuf_drain() sets s_error. */
666 else if (sbuf_extend(s, len - SBUF_FREESPACE(s)) != 0)
667 s->s_error = error = ENOMEM;
668 } while (error == 0);
671 * s->s_len is the length of the string, without the terminating nul.
672 * When updating s->s_len, we must subtract 1 from the length that
673 * we passed into vsnprintf() because that length includes the
676 * vsnprintf() returns the amount that would have been copied,
677 * given sufficient space, so don't over-increment s_len.
679 if (SBUF_FREESPACE(s) < len)
680 len = SBUF_FREESPACE(s);
682 if (SBUF_ISSECTION(s))
683 s->s_sect_len += len;
685 KASSERT(s->s_len < s->s_size,
686 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
695 * Format the given arguments and append the resulting string to an sbuf.
698 sbuf_printf(struct sbuf *s, const char *fmt, ...)
704 result = sbuf_vprintf(s, fmt, ap);
710 * Append a character to an sbuf.
713 sbuf_putc(struct sbuf *s, int c)
723 * Trim whitespace characters from end of an sbuf.
726 sbuf_trim(struct sbuf *s)
729 assert_sbuf_integrity(s);
730 assert_sbuf_state(s, 0);
731 KASSERT(s->s_drain_func == NULL,
732 ("%s makes no sense on sbuf %p with drain", __func__, s));
737 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
739 if (SBUF_ISSECTION(s))
747 * Check if an sbuf has an error.
750 sbuf_error(const struct sbuf *s)
757 * Finish off an sbuf.
760 sbuf_finish(struct sbuf *s)
763 assert_sbuf_integrity(s);
764 assert_sbuf_state(s, 0);
766 s->s_buf[s->s_len] = '\0';
767 if (SBUF_NULINCLUDED(s))
769 if (s->s_drain_func != NULL) {
770 while (s->s_len > 0 && s->s_error == 0)
771 s->s_error = sbuf_drain(s);
773 SBUF_SETFLAG(s, SBUF_FINISHED);
777 if (s->s_error != 0) {
786 * Return a pointer to the sbuf data.
789 sbuf_data(struct sbuf *s)
792 assert_sbuf_integrity(s);
793 assert_sbuf_state(s, SBUF_FINISHED);
794 KASSERT(s->s_drain_func == NULL,
795 ("%s makes no sense on sbuf %p with drain", __func__, s));
801 * Return the length of the sbuf data.
804 sbuf_len(struct sbuf *s)
807 assert_sbuf_integrity(s);
808 /* don't care if it's finished or not */
809 KASSERT(s->s_drain_func == NULL,
810 ("%s makes no sense on sbuf %p with drain", __func__, s));
815 /* If finished, nulterm is already in len, else add one. */
816 if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
817 return (s->s_len + 1);
822 * Clear an sbuf, free its buffer if necessary.
825 sbuf_delete(struct sbuf *s)
829 assert_sbuf_integrity(s);
830 /* don't care if it's finished or not */
832 if (SBUF_ISDYNAMIC(s))
834 isdyn = SBUF_ISDYNSTRUCT(s);
835 memset(s, 0, sizeof(*s));
841 * Check if an sbuf has been finished.
844 sbuf_done(const struct sbuf *s)
847 return (SBUF_ISFINISHED(s));
854 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
857 assert_sbuf_integrity(s);
858 assert_sbuf_state(s, 0);
860 if (!SBUF_ISSECTION(s)) {
861 KASSERT(s->s_sect_len == 0,
862 ("s_sect_len != 0 when starting a section"));
863 if (old_lenp != NULL)
865 s->s_rec_off = s->s_len;
866 SBUF_SETFLAG(s, SBUF_INSECTION);
868 KASSERT(old_lenp != NULL,
869 ("s_sect_len should be saved when starting a subsection"));
870 *old_lenp = s->s_sect_len;
876 * End the section padding to the specified length with the specified
880 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
884 assert_sbuf_integrity(s);
885 assert_sbuf_state(s, 0);
886 KASSERT(SBUF_ISSECTION(s),
887 ("attempt to end a section when not in a section"));
890 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
891 for (; s->s_error == 0 && len > 0; len--)
896 s->s_rec_off = s->s_sect_len = 0;
897 SBUF_CLEARFLAG(s, SBUF_INSECTION);
899 s->s_sect_len += old_len;