2 * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
35 #include <sys/ctype.h>
36 #include <sys/errno.h>
37 #include <sys/kernel.h>
38 #include <sys/limits.h>
39 #include <sys/malloc.h>
40 #include <sys/systm.h>
42 #include <machine/stdarg.h>
56 static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
57 #define SBMALLOC(size, flags) malloc(size, M_SBUF, (flags) | M_ZERO)
58 #define SBFREE(buf) free(buf, M_SBUF)
61 #define SBMALLOC(size, flags) calloc(1, size)
62 #define SBFREE(buf) free(buf)
68 #define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC)
69 #define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT)
70 #define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED)
71 #define SBUF_ISDRAINATEOL(s) ((s)->s_flags & SBUF_DRAINATEOL)
72 #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
73 #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
74 #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
75 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
76 #define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL)
77 #define SBUF_ISDRAINTOEOR(s) ((s)->s_flags & SBUF_DRAINTOEOR)
78 #define SBUF_DODRAINTOEOR(s) (SBUF_ISSECTION(s) && SBUF_ISDRAINTOEOR(s))
79 #define SBUF_MALLOCFLAG(s) \
80 (((s)->s_flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK)
85 #define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
86 #define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
88 #define SBUF_MINSIZE 2 /* Min is 1 byte + nulterm. */
89 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
92 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
93 #define SBUF_MAXEXTENDINCR PAGE_SIZE
95 #define SBUF_MAXEXTENDSIZE 4096
96 #define SBUF_MAXEXTENDINCR 4096
102 #if defined(_KERNEL) && defined(INVARIANTS)
105 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
109 ("%s called with a NULL sbuf pointer", fun));
110 KASSERT(s->s_buf != NULL,
111 ("%s called with uninitialized or corrupt sbuf", fun));
112 if (SBUF_ISFINISHED(s) && SBUF_NULINCLUDED(s)) {
113 KASSERT(s->s_len <= s->s_size,
114 ("wrote past end of sbuf (%jd >= %jd)",
115 (intmax_t)s->s_len, (intmax_t)s->s_size));
117 KASSERT(s->s_len < s->s_size,
118 ("wrote past end of sbuf (%jd >= %jd)",
119 (intmax_t)s->s_len, (intmax_t)s->s_size));
124 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
127 KASSERT((s->s_flags & SBUF_FINISHED) == state,
128 ("%s called with %sfinished or corrupt sbuf", fun,
129 (state ? "un" : "")));
132 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
133 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
135 #else /* _KERNEL && INVARIANTS */
137 #define assert_sbuf_integrity(s) do { } while (0)
138 #define assert_sbuf_state(s, i) do { } while (0)
140 #endif /* _KERNEL && INVARIANTS */
143 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
144 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
148 sbuf_extendsize(int size)
152 if (size < (int)SBUF_MAXEXTENDSIZE) {
153 newsize = SBUF_MINEXTENDSIZE;
154 while (newsize < size)
157 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
159 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
167 sbuf_extend(struct sbuf *s, int addlen)
172 if (!SBUF_CANEXTEND(s))
174 newsize = sbuf_extendsize(s->s_size + addlen);
175 newbuf = SBMALLOC(newsize, SBUF_MALLOCFLAG(s));
178 memcpy(newbuf, s->s_buf, s->s_size);
179 if (SBUF_ISDYNAMIC(s))
182 SBUF_SETFLAG(s, SBUF_DYNAMIC);
189 * Initialize an sbuf.
190 * If buf is non-NULL, it points to a static or already-allocated string
191 * big enough to hold at least length characters.
194 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
198 ("attempt to create an sbuf of negative length (%d)", length));
199 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
200 ("%s called with invalid flags", __func__));
201 KASSERT((flags & SBUF_AUTOEXTEND) || length >= SBUF_MINSIZE,
202 ("sbuf buffer %d smaller than minimum %d bytes", length,
205 flags &= SBUF_USRFLAGMSK;
208 * Allocate 'DYNSTRUCT' sbuf from the heap, if NULL 's' was provided.
211 s = SBMALLOC(sizeof(*s),
212 (flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK);
215 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
218 * DYNSTRUCT SBMALLOC sbufs are allocated with M_ZERO, but
219 * user-provided sbuf objects must be initialized.
221 memset(s, 0, sizeof(*s));
228 * Never-written sbufs do not need \n termination.
230 SBUF_SETFLAG(s, SBUF_DRAINATEOL);
233 * Allocate DYNAMIC, i.e., heap data buffer backing the sbuf, if no
234 * buffer was provided.
236 if (s->s_buf == NULL) {
237 if (SBUF_CANEXTEND(s))
238 s->s_size = sbuf_extendsize(s->s_size);
239 s->s_buf = SBMALLOC(s->s_size, SBUF_MALLOCFLAG(s));
240 if (s->s_buf == NULL)
242 SBUF_SETFLAG(s, SBUF_DYNAMIC);
246 if (s != NULL && s->s_buf == NULL) {
247 if (SBUF_ISDYNSTRUCT(s))
256 * Create an sbuf with uio data
259 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
263 ("%s called with NULL uio pointer", __func__));
264 KASSERT(error != NULL,
265 ("%s called with NULL error pointer", __func__));
267 if (uio->uio_resid >= INT_MAX || uio->uio_resid < SBUF_MINSIZE - 1) {
271 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
276 *error = uiomove(s->s_buf, uio->uio_resid, uio);
281 s->s_len = s->s_size - 1;
282 if (SBUF_ISSECTION(s))
283 s->s_sect_len = s->s_size - 1;
290 sbuf_get_flags(struct sbuf *s)
293 return (s->s_flags & SBUF_USRFLAGMSK);
297 sbuf_clear_flags(struct sbuf *s, int flags)
300 s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
304 sbuf_set_flags(struct sbuf *s, int flags)
307 s->s_flags |= (flags & SBUF_USRFLAGMSK);
311 * Clear an sbuf and reset its position.
314 sbuf_clear(struct sbuf *s)
317 assert_sbuf_integrity(s);
318 /* don't care if it's finished or not */
319 KASSERT(s->s_drain_func == NULL,
320 ("%s makes no sense on sbuf %p with drain", __func__, s));
322 SBUF_CLEARFLAG(s, SBUF_FINISHED);
330 * Set the sbuf's end position to an arbitrary value.
331 * Effectively truncates the sbuf at the new position.
334 sbuf_setpos(struct sbuf *s, ssize_t pos)
337 assert_sbuf_integrity(s);
338 assert_sbuf_state(s, 0);
341 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
342 KASSERT(pos < s->s_size,
343 ("attempt to seek past end of sbuf (%jd >= %jd)",
344 (intmax_t)pos, (intmax_t)s->s_size));
345 KASSERT(!SBUF_ISSECTION(s),
346 ("attempt to seek when in a section"));
348 if (pos < 0 || pos > s->s_len)
355 * Drain into a counter. Counts amount of data without producing output.
356 * Useful for cases like sysctl, where user may first request only size.
357 * This allows to avoid pointless allocation/freeing of large buffers.
360 sbuf_count_drain(void *arg, const char *data __unused, int len)
364 sizep = (size_t *)arg;
370 * Set up a drain function and argument on an sbuf to flush data to
371 * when the sbuf buffer overflows.
374 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
377 assert_sbuf_state(s, 0);
378 assert_sbuf_integrity(s);
379 KASSERT(func == s->s_drain_func || s->s_len == 0,
380 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
381 s->s_drain_func = func;
382 s->s_drain_arg = ctx;
386 * Call the drain and process the return.
389 sbuf_drain(struct sbuf *s)
394 * Immediately return when no work to do,
395 * or an error has already been accumulated.
397 if ((s->s_len == 0) || (s->s_error != 0))
400 if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
401 return (s->s_error = EDEADLK);
402 len = s->s_drain_func(s->s_drain_arg, s->s_buf,
403 SBUF_DODRAINTOEOR(s) ? s->s_rec_off : s->s_len);
405 s->s_error = len ? -len : EDEADLK;
408 KASSERT(len > 0 && len <= s->s_len,
409 ("Bad drain amount %d for sbuf %p", len, s));
413 * Fast path for the expected case where all the data was
418 * When the s_buf is entirely drained, we need to remember if
419 * the last character was a '\n' or not for
420 * sbuf_nl_terminate().
422 if (s->s_buf[len - 1] == '\n')
423 SBUF_SETFLAG(s, SBUF_DRAINATEOL);
425 SBUF_CLEARFLAG(s, SBUF_DRAINATEOL);
429 * Move the remaining characters to the beginning of the
432 memmove(s->s_buf, s->s_buf + len, s->s_len);
437 * Append bytes to an sbuf. This is the core function for appending
438 * to an sbuf and is the main place that deals with extending the
439 * buffer and marking overflow.
442 sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
446 assert_sbuf_integrity(s);
447 assert_sbuf_state(s, 0);
452 if (SBUF_FREESPACE(s) <= 0) {
454 * If there is a drain, use it, otherwise extend the
457 if (s->s_drain_func != NULL)
459 else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
465 n = SBUF_FREESPACE(s);
468 memcpy(&s->s_buf[s->s_len], buf, n);
470 if (SBUF_ISSECTION(s))
478 sbuf_put_byte(struct sbuf *s, char c)
481 assert_sbuf_integrity(s);
482 assert_sbuf_state(s, 0);
484 if (__predict_false(s->s_error != 0))
486 if (__predict_false(SBUF_FREESPACE(s) <= 0)) {
488 * If there is a drain, use it, otherwise extend the
491 if (s->s_drain_func != NULL)
493 else if (sbuf_extend(s, 1) < 0)
498 s->s_buf[s->s_len++] = c;
499 if (SBUF_ISSECTION(s))
504 * Append a byte string to an sbuf.
507 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
510 sbuf_put_bytes(s, buf, len);
518 * Copy a byte string from userland into an sbuf.
521 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
524 assert_sbuf_integrity(s);
525 assert_sbuf_state(s, 0);
526 KASSERT(s->s_drain_func == NULL,
527 ("Nonsensical copyin to sbuf %p with a drain", s));
533 if (len > SBUF_FREESPACE(s)) {
534 sbuf_extend(s, len - SBUF_FREESPACE(s));
535 if (SBUF_FREESPACE(s) < len)
536 len = SBUF_FREESPACE(s);
538 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
547 * Copy a byte string into an sbuf.
550 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
553 assert_sbuf_integrity(s);
554 assert_sbuf_state(s, 0);
557 return (sbuf_bcat(s, buf, len));
561 * Append a string to an sbuf.
564 sbuf_cat(struct sbuf *s, const char *str)
569 sbuf_put_bytes(s, str, n);
577 * Append a string from userland to an sbuf.
580 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
584 assert_sbuf_integrity(s);
585 assert_sbuf_state(s, 0);
586 KASSERT(s->s_drain_func == NULL,
587 ("Nonsensical copyin to sbuf %p with a drain", s));
593 len = SBUF_FREESPACE(s); /* XXX return 0? */
594 if (len > SBUF_FREESPACE(s)) {
596 if (SBUF_FREESPACE(s) < len)
597 len = SBUF_FREESPACE(s);
599 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
604 s->s_len += done - 1;
605 if (SBUF_ISSECTION(s))
606 s->s_sect_len += done - 1;
609 return (-1); /* XXX */
617 * Copy a string into an sbuf.
620 sbuf_cpy(struct sbuf *s, const char *str)
623 assert_sbuf_integrity(s);
624 assert_sbuf_state(s, 0);
627 return (sbuf_cat(s, str));
631 * Format the given argument list and append the resulting string to an sbuf.
636 * Append a non-NUL character to an sbuf. This prototype signature is
637 * suitable for use with kvprintf(9).
640 sbuf_putc_func(int c, void *arg)
643 if (__predict_true(c != '\0'))
644 sbuf_put_byte(arg, c);
648 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
651 assert_sbuf_integrity(s);
652 assert_sbuf_state(s, 0);
655 ("%s called with a NULL format string", __func__));
657 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
664 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
669 assert_sbuf_integrity(s);
670 assert_sbuf_state(s, 0);
673 ("%s called with a NULL format string", __func__));
679 * For the moment, there is no way to get vsnprintf(3) to hand
680 * back a character at a time, to push everything into
681 * sbuf_putc_func() as was done for the kernel.
683 * In userspace, while drains are useful, there's generally
684 * not a problem attempting to malloc(3) on out of space. So
685 * expand a userland sbuf if there is not enough room for the
686 * data produced by sbuf_[v]printf(3).
691 va_copy(ap_copy, ap);
692 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
700 if (SBUF_FREESPACE(s) >= len)
702 /* Cannot print with the current available space. */
703 if (s->s_drain_func != NULL && s->s_len > 0)
704 error = sbuf_drain(s); /* sbuf_drain() sets s_error. */
705 else if (sbuf_extend(s, len - SBUF_FREESPACE(s)) != 0)
706 s->s_error = error = ENOMEM;
707 } while (error == 0);
710 * s->s_len is the length of the string, without the terminating nul.
711 * When updating s->s_len, we must subtract 1 from the length that
712 * we passed into vsnprintf() because that length includes the
715 * vsnprintf() returns the amount that would have been copied,
716 * given sufficient space, so don't over-increment s_len.
718 if (SBUF_FREESPACE(s) < len)
719 len = SBUF_FREESPACE(s);
721 if (SBUF_ISSECTION(s))
722 s->s_sect_len += len;
724 KASSERT(s->s_len < s->s_size,
725 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
734 * Format the given arguments and append the resulting string to an sbuf.
737 sbuf_printf(struct sbuf *s, const char *fmt, ...)
743 result = sbuf_vprintf(s, fmt, ap);
749 * Append a character to an sbuf.
752 sbuf_putc(struct sbuf *s, int c)
762 * Append a trailing newline to a non-empty sbuf, if one is not already
763 * present. Handles sbufs with drain functions correctly.
766 sbuf_nl_terminate(struct sbuf *s)
769 assert_sbuf_integrity(s);
770 assert_sbuf_state(s, 0);
773 * If the s_buf isn't empty, the last byte is simply s_buf[s_len - 1].
775 * If the s_buf is empty because a drain function drained it, we
776 * remember if the last byte was a \n with the SBUF_DRAINATEOL flag in
779 * In either case, we only append a \n if the previous character was
783 if (!SBUF_ISDRAINATEOL(s))
784 sbuf_put_byte(s, '\n');
785 } else if (s->s_buf[s->s_len - 1] != '\n')
786 sbuf_put_byte(s, '\n');
794 * Trim whitespace characters from end of an sbuf.
797 sbuf_trim(struct sbuf *s)
800 assert_sbuf_integrity(s);
801 assert_sbuf_state(s, 0);
802 KASSERT(s->s_drain_func == NULL,
803 ("%s makes no sense on sbuf %p with drain", __func__, s));
808 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
810 if (SBUF_ISSECTION(s))
818 * Check if an sbuf has an error.
821 sbuf_error(const struct sbuf *s)
828 * Finish off an sbuf.
831 sbuf_finish(struct sbuf *s)
834 assert_sbuf_integrity(s);
835 assert_sbuf_state(s, 0);
837 s->s_buf[s->s_len] = '\0';
838 if (SBUF_NULINCLUDED(s))
840 if (s->s_drain_func != NULL) {
841 while (s->s_len > 0 && s->s_error == 0)
842 s->s_error = sbuf_drain(s);
844 SBUF_SETFLAG(s, SBUF_FINISHED);
848 if (s->s_error != 0) {
857 * Return a pointer to the sbuf data.
860 sbuf_data(struct sbuf *s)
863 assert_sbuf_integrity(s);
864 assert_sbuf_state(s, SBUF_FINISHED);
865 KASSERT(s->s_drain_func == NULL,
866 ("%s makes no sense on sbuf %p with drain", __func__, s));
872 * Return the length of the sbuf data.
875 sbuf_len(struct sbuf *s)
878 assert_sbuf_integrity(s);
879 /* don't care if it's finished or not */
880 KASSERT(s->s_drain_func == NULL,
881 ("%s makes no sense on sbuf %p with drain", __func__, s));
886 /* If finished, nulterm is already in len, else add one. */
887 if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
888 return (s->s_len + 1);
893 * Clear an sbuf, free its buffer if necessary.
896 sbuf_delete(struct sbuf *s)
900 assert_sbuf_integrity(s);
901 /* don't care if it's finished or not */
903 if (SBUF_ISDYNAMIC(s))
905 isdyn = SBUF_ISDYNSTRUCT(s);
906 memset(s, 0, sizeof(*s));
912 * Check if an sbuf has been finished.
915 sbuf_done(const struct sbuf *s)
918 return (SBUF_ISFINISHED(s));
925 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
928 assert_sbuf_integrity(s);
929 assert_sbuf_state(s, 0);
931 if (!SBUF_ISSECTION(s)) {
932 KASSERT(s->s_sect_len == 0,
933 ("s_sect_len != 0 when starting a section"));
934 if (old_lenp != NULL)
936 s->s_rec_off = s->s_len;
937 SBUF_SETFLAG(s, SBUF_INSECTION);
939 KASSERT(old_lenp != NULL,
940 ("s_sect_len should be saved when starting a subsection"));
941 *old_lenp = s->s_sect_len;
947 * End the section padding to the specified length with the specified
951 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
955 assert_sbuf_integrity(s);
956 assert_sbuf_state(s, 0);
957 KASSERT(SBUF_ISSECTION(s),
958 ("attempt to end a section when not in a section"));
961 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
962 for (; s->s_error == 0 && len > 0; len--)
967 s->s_rec_off = s->s_sect_len = 0;
968 SBUF_CLEARFLAG(s, SBUF_INSECTION);
970 s->s_sect_len += old_len;