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 if (uio->uio_resid >= INT_MAX || uio->uio_resid < SBUF_MINSIZE - 1) {
266 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
271 *error = uiomove(s->s_buf, uio->uio_resid, uio);
276 s->s_len = s->s_size - 1;
277 if (SBUF_ISSECTION(s))
278 s->s_sect_len = s->s_size - 1;
285 sbuf_get_flags(struct sbuf *s)
288 return (s->s_flags & SBUF_USRFLAGMSK);
292 sbuf_clear_flags(struct sbuf *s, int flags)
295 s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
299 sbuf_set_flags(struct sbuf *s, int flags)
303 s->s_flags |= (flags & SBUF_USRFLAGMSK);
307 * Clear an sbuf and reset its position.
310 sbuf_clear(struct sbuf *s)
313 assert_sbuf_integrity(s);
314 /* don't care if it's finished or not */
316 SBUF_CLEARFLAG(s, SBUF_FINISHED);
324 * Set the sbuf's end position to an arbitrary value.
325 * Effectively truncates the sbuf at the new position.
328 sbuf_setpos(struct sbuf *s, ssize_t pos)
331 assert_sbuf_integrity(s);
332 assert_sbuf_state(s, 0);
335 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
336 KASSERT(pos < s->s_size,
337 ("attempt to seek past end of sbuf (%jd >= %jd)",
338 (intmax_t)pos, (intmax_t)s->s_size));
339 KASSERT(!SBUF_ISSECTION(s),
340 ("attempt to seek when in a section"));
342 if (pos < 0 || pos > s->s_len)
349 * Drain into a counter. Counts amount of data without producing output.
350 * Useful for cases like sysctl, where user may first request only size.
351 * This allows to avoid pointless allocation/freeing of large buffers.
354 sbuf_count_drain(void *arg, const char *data __unused, int len)
358 sizep = (size_t *)arg;
364 * Set up a drain function and argument on an sbuf to flush data to
365 * when the sbuf buffer overflows.
368 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
371 assert_sbuf_state(s, 0);
372 assert_sbuf_integrity(s);
373 KASSERT(func == s->s_drain_func || s->s_len == 0,
374 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
375 s->s_drain_func = func;
376 s->s_drain_arg = ctx;
380 * Call the drain and process the return.
383 sbuf_drain(struct sbuf *s)
388 * Immediately return when no work to do,
389 * or an error has already been accumulated.
391 if ((s->s_len == 0) || (s->s_error != 0))
394 if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
395 return (s->s_error = EDEADLK);
396 len = s->s_drain_func(s->s_drain_arg, s->s_buf,
397 SBUF_DODRAINTOEOR(s) ? s->s_rec_off : s->s_len);
399 s->s_error = len ? -len : EDEADLK;
402 KASSERT(len > 0 && len <= s->s_len,
403 ("Bad drain amount %d for sbuf %p", len, s));
407 * Fast path for the expected case where all the data was
413 * Move the remaining characters to the beginning of the
416 memmove(s->s_buf, s->s_buf + len, s->s_len);
421 * Append bytes to an sbuf. This is the core function for appending
422 * to an sbuf and is the main place that deals with extending the
423 * buffer and marking overflow.
426 sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
430 assert_sbuf_integrity(s);
431 assert_sbuf_state(s, 0);
436 if (SBUF_FREESPACE(s) <= 0) {
438 * If there is a drain, use it, otherwise extend the
441 if (s->s_drain_func != NULL)
443 else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
449 n = SBUF_FREESPACE(s);
452 memcpy(&s->s_buf[s->s_len], buf, n);
454 if (SBUF_ISSECTION(s))
462 sbuf_put_byte(struct sbuf *s, char c)
465 sbuf_put_bytes(s, &c, 1);
469 * Append a byte string to an sbuf.
472 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
475 sbuf_put_bytes(s, buf, len);
483 * Copy a byte string from userland into an sbuf.
486 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
489 assert_sbuf_integrity(s);
490 assert_sbuf_state(s, 0);
491 KASSERT(s->s_drain_func == NULL,
492 ("Nonsensical copyin to sbuf %p with a drain", s));
498 if (len > SBUF_FREESPACE(s)) {
499 sbuf_extend(s, len - SBUF_FREESPACE(s));
500 if (SBUF_FREESPACE(s) < len)
501 len = SBUF_FREESPACE(s);
503 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
512 * Copy a byte string into an sbuf.
515 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
518 assert_sbuf_integrity(s);
519 assert_sbuf_state(s, 0);
522 return (sbuf_bcat(s, buf, len));
526 * Append a string to an sbuf.
529 sbuf_cat(struct sbuf *s, const char *str)
534 sbuf_put_bytes(s, str, n);
542 * Append a string from userland to an sbuf.
545 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
549 assert_sbuf_integrity(s);
550 assert_sbuf_state(s, 0);
551 KASSERT(s->s_drain_func == NULL,
552 ("Nonsensical copyin to sbuf %p with a drain", s));
558 len = SBUF_FREESPACE(s); /* XXX return 0? */
559 if (len > SBUF_FREESPACE(s)) {
561 if (SBUF_FREESPACE(s) < len)
562 len = SBUF_FREESPACE(s);
564 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
569 s->s_len += done - 1;
570 if (SBUF_ISSECTION(s))
571 s->s_sect_len += done - 1;
574 return (-1); /* XXX */
582 * Copy a string into an sbuf.
585 sbuf_cpy(struct sbuf *s, const char *str)
588 assert_sbuf_integrity(s);
589 assert_sbuf_state(s, 0);
592 return (sbuf_cat(s, str));
596 * Format the given argument list and append the resulting string to an sbuf.
601 * Append a non-NUL character to an sbuf. This prototype signature is
602 * suitable for use with kvprintf(9).
605 sbuf_putc_func(int c, void *arg)
609 sbuf_put_byte(arg, c);
613 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
616 assert_sbuf_integrity(s);
617 assert_sbuf_state(s, 0);
620 ("%s called with a NULL format string", __func__));
622 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
629 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
634 assert_sbuf_integrity(s);
635 assert_sbuf_state(s, 0);
638 ("%s called with a NULL format string", __func__));
644 * For the moment, there is no way to get vsnprintf(3) to hand
645 * back a character at a time, to push everything into
646 * sbuf_putc_func() as was done for the kernel.
648 * In userspace, while drains are useful, there's generally
649 * not a problem attempting to malloc(3) on out of space. So
650 * expand a userland sbuf if there is not enough room for the
651 * data produced by sbuf_[v]printf(3).
656 va_copy(ap_copy, ap);
657 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
665 if (SBUF_FREESPACE(s) >= len)
667 /* Cannot print with the current available space. */
668 if (s->s_drain_func != NULL && s->s_len > 0)
669 error = sbuf_drain(s); /* sbuf_drain() sets s_error. */
670 else if (sbuf_extend(s, len - SBUF_FREESPACE(s)) != 0)
671 s->s_error = error = ENOMEM;
672 } while (error == 0);
675 * s->s_len is the length of the string, without the terminating nul.
676 * When updating s->s_len, we must subtract 1 from the length that
677 * we passed into vsnprintf() because that length includes the
680 * vsnprintf() returns the amount that would have been copied,
681 * given sufficient space, so don't over-increment s_len.
683 if (SBUF_FREESPACE(s) < len)
684 len = SBUF_FREESPACE(s);
686 if (SBUF_ISSECTION(s))
687 s->s_sect_len += len;
689 KASSERT(s->s_len < s->s_size,
690 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
699 * Format the given arguments and append the resulting string to an sbuf.
702 sbuf_printf(struct sbuf *s, const char *fmt, ...)
708 result = sbuf_vprintf(s, fmt, ap);
714 * Append a character to an sbuf.
717 sbuf_putc(struct sbuf *s, int c)
727 * Trim whitespace characters from end of an sbuf.
730 sbuf_trim(struct sbuf *s)
733 assert_sbuf_integrity(s);
734 assert_sbuf_state(s, 0);
735 KASSERT(s->s_drain_func == NULL,
736 ("%s makes no sense on sbuf %p with drain", __func__, s));
741 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
743 if (SBUF_ISSECTION(s))
751 * Check if an sbuf has an error.
754 sbuf_error(const struct sbuf *s)
761 * Finish off an sbuf.
764 sbuf_finish(struct sbuf *s)
767 assert_sbuf_integrity(s);
768 assert_sbuf_state(s, 0);
770 s->s_buf[s->s_len] = '\0';
771 if (SBUF_NULINCLUDED(s))
773 if (s->s_drain_func != NULL) {
774 while (s->s_len > 0 && s->s_error == 0)
775 s->s_error = sbuf_drain(s);
777 SBUF_SETFLAG(s, SBUF_FINISHED);
781 if (s->s_error != 0) {
790 * Return a pointer to the sbuf data.
793 sbuf_data(struct sbuf *s)
796 assert_sbuf_integrity(s);
797 assert_sbuf_state(s, SBUF_FINISHED);
798 KASSERT(s->s_drain_func == NULL,
799 ("%s makes no sense on sbuf %p with drain", __func__, s));
805 * Return the length of the sbuf data.
808 sbuf_len(struct sbuf *s)
811 assert_sbuf_integrity(s);
812 /* don't care if it's finished or not */
813 KASSERT(s->s_drain_func == NULL,
814 ("%s makes no sense on sbuf %p with drain", __func__, s));
819 /* If finished, nulterm is already in len, else add one. */
820 if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
821 return (s->s_len + 1);
826 * Clear an sbuf, free its buffer if necessary.
829 sbuf_delete(struct sbuf *s)
833 assert_sbuf_integrity(s);
834 /* don't care if it's finished or not */
836 if (SBUF_ISDYNAMIC(s))
838 isdyn = SBUF_ISDYNSTRUCT(s);
839 memset(s, 0, sizeof(*s));
845 * Check if an sbuf has been finished.
848 sbuf_done(const struct sbuf *s)
851 return (SBUF_ISFINISHED(s));
858 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
861 assert_sbuf_integrity(s);
862 assert_sbuf_state(s, 0);
864 if (!SBUF_ISSECTION(s)) {
865 KASSERT(s->s_sect_len == 0,
866 ("s_sect_len != 0 when starting a section"));
867 if (old_lenp != NULL)
869 s->s_rec_off = s->s_len;
870 SBUF_SETFLAG(s, SBUF_INSECTION);
872 KASSERT(old_lenp != NULL,
873 ("s_sect_len should be saved when starting a subsection"));
874 *old_lenp = s->s_sect_len;
880 * End the section padding to the specified length with the specified
884 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
888 assert_sbuf_integrity(s);
889 assert_sbuf_state(s, 0);
890 KASSERT(SBUF_ISSECTION(s),
891 ("attempt to end a section when not in a section"));
894 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
895 for (; s->s_error == 0 && len > 0; len--)
900 s->s_rec_off = s->s_sect_len = 0;
901 SBUF_CLEARFLAG(s, SBUF_INSECTION);
903 s->s_sect_len += old_len;