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, flags) malloc(size, M_SBUF, (flags) | M_ZERO)
60 #define SBFREE(buf) free(buf, M_SBUF)
63 #define SBMALLOC(size, flags) 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_ISDRAINATEOL(s) ((s)->s_flags & SBUF_DRAINATEOL)
74 #define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
75 #define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
76 #define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
77 #define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
78 #define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL)
79 #define SBUF_ISDRAINTOEOR(s) ((s)->s_flags & SBUF_DRAINTOEOR)
80 #define SBUF_DODRAINTOEOR(s) (SBUF_ISSECTION(s) && SBUF_ISDRAINTOEOR(s))
81 #define SBUF_MALLOCFLAG(s) \
82 (((s)->s_flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK)
87 #define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
88 #define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
90 #define SBUF_MINSIZE 2 /* Min is 1 byte + nulterm. */
91 #define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
94 #define SBUF_MAXEXTENDSIZE PAGE_SIZE
95 #define SBUF_MAXEXTENDINCR PAGE_SIZE
97 #define SBUF_MAXEXTENDSIZE 4096
98 #define SBUF_MAXEXTENDINCR 4096
104 #if defined(_KERNEL) && defined(INVARIANTS)
107 _assert_sbuf_integrity(const char *fun, struct sbuf *s)
111 ("%s called with a NULL sbuf pointer", fun));
112 KASSERT(s->s_buf != NULL,
113 ("%s called with uninitialized or corrupt sbuf", fun));
114 if (SBUF_ISFINISHED(s) && SBUF_NULINCLUDED(s)) {
115 KASSERT(s->s_len <= s->s_size,
116 ("wrote past end of sbuf (%jd >= %jd)",
117 (intmax_t)s->s_len, (intmax_t)s->s_size));
119 KASSERT(s->s_len < s->s_size,
120 ("wrote past end of sbuf (%jd >= %jd)",
121 (intmax_t)s->s_len, (intmax_t)s->s_size));
126 _assert_sbuf_state(const char *fun, struct sbuf *s, int state)
129 KASSERT((s->s_flags & SBUF_FINISHED) == state,
130 ("%s called with %sfinished or corrupt sbuf", fun,
131 (state ? "un" : "")));
134 #define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
135 #define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
137 #else /* _KERNEL && INVARIANTS */
139 #define assert_sbuf_integrity(s) do { } while (0)
140 #define assert_sbuf_state(s, i) do { } while (0)
142 #endif /* _KERNEL && INVARIANTS */
145 CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
146 CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
150 sbuf_extendsize(int size)
154 if (size < (int)SBUF_MAXEXTENDSIZE) {
155 newsize = SBUF_MINEXTENDSIZE;
156 while (newsize < size)
159 newsize = roundup2(size, SBUF_MAXEXTENDINCR);
161 KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
169 sbuf_extend(struct sbuf *s, int addlen)
174 if (!SBUF_CANEXTEND(s))
176 newsize = sbuf_extendsize(s->s_size + addlen);
177 newbuf = SBMALLOC(newsize, SBUF_MALLOCFLAG(s));
180 memcpy(newbuf, s->s_buf, s->s_size);
181 if (SBUF_ISDYNAMIC(s))
184 SBUF_SETFLAG(s, SBUF_DYNAMIC);
191 * Initialize an sbuf.
192 * If buf is non-NULL, it points to a static or already-allocated string
193 * big enough to hold at least length characters.
196 sbuf_new(struct sbuf *s, char *buf, int length, int flags)
200 ("attempt to create an sbuf of negative length (%d)", length));
201 KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
202 ("%s called with invalid flags", __func__));
203 KASSERT((flags & SBUF_AUTOEXTEND) || length >= SBUF_MINSIZE,
204 ("sbuf buffer %d smaller than minimum %d bytes", length,
207 flags &= SBUF_USRFLAGMSK;
210 * Allocate 'DYNSTRUCT' sbuf from the heap, if NULL 's' was provided.
213 s = SBMALLOC(sizeof(*s),
214 (flags & SBUF_NOWAIT) ? M_NOWAIT : M_WAITOK);
217 SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
220 * DYNSTRUCT SBMALLOC sbufs are allocated with M_ZERO, but
221 * user-provided sbuf objects must be initialized.
223 memset(s, 0, sizeof(*s));
230 * Never-written sbufs do not need \n termination.
232 SBUF_SETFLAG(s, SBUF_DRAINATEOL);
235 * Allocate DYNAMIC, i.e., heap data buffer backing the sbuf, if no
236 * buffer was provided.
238 if (s->s_buf == NULL) {
239 if (SBUF_CANEXTEND(s))
240 s->s_size = sbuf_extendsize(s->s_size);
241 s->s_buf = SBMALLOC(s->s_size, SBUF_MALLOCFLAG(s));
242 if (s->s_buf == NULL)
244 SBUF_SETFLAG(s, SBUF_DYNAMIC);
248 if (s != NULL && s->s_buf == NULL) {
249 if (SBUF_ISDYNSTRUCT(s))
258 * Create an sbuf with uio data
261 sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
265 ("%s called with NULL uio pointer", __func__));
266 KASSERT(error != NULL,
267 ("%s called with NULL error pointer", __func__));
269 s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
274 *error = uiomove(s->s_buf, uio->uio_resid, uio);
279 s->s_len = s->s_size - 1;
280 if (SBUF_ISSECTION(s))
281 s->s_sect_len = s->s_size - 1;
288 sbuf_get_flags(struct sbuf *s)
291 return (s->s_flags & SBUF_USRFLAGMSK);
295 sbuf_clear_flags(struct sbuf *s, int flags)
298 s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
302 sbuf_set_flags(struct sbuf *s, int flags)
306 s->s_flags |= (flags & SBUF_USRFLAGMSK);
310 * Clear an sbuf and reset its position.
313 sbuf_clear(struct sbuf *s)
316 assert_sbuf_integrity(s);
317 /* don't care if it's finished or not */
318 KASSERT(s->s_drain_func == NULL,
319 ("%s makes no sense on sbuf %p with drain", __func__, s));
321 SBUF_CLEARFLAG(s, SBUF_FINISHED);
329 * Set the sbuf's end position to an arbitrary value.
330 * Effectively truncates the sbuf at the new position.
333 sbuf_setpos(struct sbuf *s, ssize_t pos)
336 assert_sbuf_integrity(s);
337 assert_sbuf_state(s, 0);
340 ("attempt to seek to a negative position (%jd)", (intmax_t)pos));
341 KASSERT(pos < s->s_size,
342 ("attempt to seek past end of sbuf (%jd >= %jd)",
343 (intmax_t)pos, (intmax_t)s->s_size));
344 KASSERT(!SBUF_ISSECTION(s),
345 ("attempt to seek when in a section"));
347 if (pos < 0 || pos > s->s_len)
354 * Drain into a counter. Counts amount of data without producing output.
355 * Useful for cases like sysctl, where user may first request only size.
356 * This allows to avoid pointless allocation/freeing of large buffers.
359 sbuf_count_drain(void *arg, const char *data __unused, int len)
363 sizep = (size_t *)arg;
369 * Set up a drain function and argument on an sbuf to flush data to
370 * when the sbuf buffer overflows.
373 sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
376 assert_sbuf_state(s, 0);
377 assert_sbuf_integrity(s);
378 KASSERT(func == s->s_drain_func || s->s_len == 0,
379 ("Cannot change drain to %p on non-empty sbuf %p", func, s));
380 s->s_drain_func = func;
381 s->s_drain_arg = ctx;
385 * Call the drain and process the return.
388 sbuf_drain(struct sbuf *s)
392 KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
393 KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
395 if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
396 return (s->s_error = EDEADLK);
397 len = s->s_drain_func(s->s_drain_arg, s->s_buf,
398 SBUF_DODRAINTOEOR(s) ? s->s_rec_off : s->s_len);
400 s->s_error = len ? -len : EDEADLK;
403 KASSERT(len > 0 && len <= s->s_len,
404 ("Bad drain amount %d for sbuf %p", len, s));
408 * Fast path for the expected case where all the data was
413 * When the s_buf is entirely drained, we need to remember if
414 * the last character was a '\n' or not for
415 * sbuf_nl_terminate().
417 if (s->s_buf[len - 1] == '\n')
418 SBUF_SETFLAG(s, SBUF_DRAINATEOL);
420 SBUF_CLEARFLAG(s, SBUF_DRAINATEOL);
424 * Move the remaining characters to the beginning of the
427 memmove(s->s_buf, s->s_buf + len, s->s_len);
432 * Append bytes to an sbuf. This is the core function for appending
433 * to an sbuf and is the main place that deals with extending the
434 * buffer and marking overflow.
437 sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
441 assert_sbuf_integrity(s);
442 assert_sbuf_state(s, 0);
447 if (SBUF_FREESPACE(s) <= 0) {
449 * If there is a drain, use it, otherwise extend the
452 if (s->s_drain_func != NULL)
454 else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
460 n = SBUF_FREESPACE(s);
463 memcpy(&s->s_buf[s->s_len], buf, n);
465 if (SBUF_ISSECTION(s))
473 sbuf_put_byte(struct sbuf *s, char c)
476 sbuf_put_bytes(s, &c, 1);
480 * Append a byte string to an sbuf.
483 sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
486 sbuf_put_bytes(s, buf, len);
494 * Copy a byte string from userland into an sbuf.
497 sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
500 assert_sbuf_integrity(s);
501 assert_sbuf_state(s, 0);
502 KASSERT(s->s_drain_func == NULL,
503 ("Nonsensical copyin to sbuf %p with a drain", s));
509 if (len > SBUF_FREESPACE(s)) {
510 sbuf_extend(s, len - SBUF_FREESPACE(s));
511 if (SBUF_FREESPACE(s) < len)
512 len = SBUF_FREESPACE(s);
514 if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
523 * Copy a byte string into an sbuf.
526 sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
529 assert_sbuf_integrity(s);
530 assert_sbuf_state(s, 0);
533 return (sbuf_bcat(s, buf, len));
537 * Append a string to an sbuf.
540 sbuf_cat(struct sbuf *s, const char *str)
545 sbuf_put_bytes(s, str, n);
553 * Append a string from userland to an sbuf.
556 sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
560 assert_sbuf_integrity(s);
561 assert_sbuf_state(s, 0);
562 KASSERT(s->s_drain_func == NULL,
563 ("Nonsensical copyin to sbuf %p with a drain", s));
569 len = SBUF_FREESPACE(s); /* XXX return 0? */
570 if (len > SBUF_FREESPACE(s)) {
572 if (SBUF_FREESPACE(s) < len)
573 len = SBUF_FREESPACE(s);
575 switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
580 s->s_len += done - 1;
581 if (SBUF_ISSECTION(s))
582 s->s_sect_len += done - 1;
585 return (-1); /* XXX */
593 * Copy a string into an sbuf.
596 sbuf_cpy(struct sbuf *s, const char *str)
599 assert_sbuf_integrity(s);
600 assert_sbuf_state(s, 0);
603 return (sbuf_cat(s, str));
607 * Format the given argument list and append the resulting string to an sbuf.
612 * Append a non-NUL character to an sbuf. This prototype signature is
613 * suitable for use with kvprintf(9).
616 sbuf_putc_func(int c, void *arg)
620 sbuf_put_byte(arg, c);
624 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
627 assert_sbuf_integrity(s);
628 assert_sbuf_state(s, 0);
631 ("%s called with a NULL format string", __func__));
633 (void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
640 sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
645 assert_sbuf_integrity(s);
646 assert_sbuf_state(s, 0);
649 ("%s called with a NULL format string", __func__));
655 * For the moment, there is no way to get vsnprintf(3) to hand
656 * back a character at a time, to push everything into
657 * sbuf_putc_func() as was done for the kernel.
659 * In userspace, while drains are useful, there's generally
660 * not a problem attempting to malloc(3) on out of space. So
661 * expand a userland sbuf if there is not enough room for the
662 * data produced by sbuf_[v]printf(3).
667 va_copy(ap_copy, ap);
668 len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
676 if (SBUF_FREESPACE(s) >= len)
678 /* Cannot print with the current available space. */
679 if (s->s_drain_func != NULL && s->s_len > 0)
680 error = sbuf_drain(s); /* sbuf_drain() sets s_error. */
681 else if (sbuf_extend(s, len - SBUF_FREESPACE(s)) != 0)
682 s->s_error = error = ENOMEM;
683 } while (error == 0);
686 * s->s_len is the length of the string, without the terminating nul.
687 * When updating s->s_len, we must subtract 1 from the length that
688 * we passed into vsnprintf() because that length includes the
691 * vsnprintf() returns the amount that would have been copied,
692 * given sufficient space, so don't over-increment s_len.
694 if (SBUF_FREESPACE(s) < len)
695 len = SBUF_FREESPACE(s);
697 if (SBUF_ISSECTION(s))
698 s->s_sect_len += len;
700 KASSERT(s->s_len < s->s_size,
701 ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
710 * Format the given arguments and append the resulting string to an sbuf.
713 sbuf_printf(struct sbuf *s, const char *fmt, ...)
719 result = sbuf_vprintf(s, fmt, ap);
725 * Append a character to an sbuf.
728 sbuf_putc(struct sbuf *s, int c)
738 * Append a trailing newline to a non-empty sbuf, if one is not already
739 * present. Handles sbufs with drain functions correctly.
742 sbuf_nl_terminate(struct sbuf *s)
745 assert_sbuf_integrity(s);
746 assert_sbuf_state(s, 0);
749 * If the s_buf isn't empty, the last byte is simply s_buf[s_len - 1].
751 * If the s_buf is empty because a drain function drained it, we
752 * remember if the last byte was a \n with the SBUF_DRAINATEOL flag in
755 * In either case, we only append a \n if the previous character was
759 if (!SBUF_ISDRAINATEOL(s))
760 sbuf_put_byte(s, '\n');
761 } else if (s->s_buf[s->s_len - 1] != '\n')
762 sbuf_put_byte(s, '\n');
770 * Trim whitespace characters from end of an sbuf.
773 sbuf_trim(struct sbuf *s)
776 assert_sbuf_integrity(s);
777 assert_sbuf_state(s, 0);
778 KASSERT(s->s_drain_func == NULL,
779 ("%s makes no sense on sbuf %p with drain", __func__, s));
784 while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
786 if (SBUF_ISSECTION(s))
794 * Check if an sbuf has an error.
797 sbuf_error(const struct sbuf *s)
804 * Finish off an sbuf.
807 sbuf_finish(struct sbuf *s)
810 assert_sbuf_integrity(s);
811 assert_sbuf_state(s, 0);
813 s->s_buf[s->s_len] = '\0';
814 if (SBUF_NULINCLUDED(s))
816 if (s->s_drain_func != NULL) {
817 while (s->s_len > 0 && s->s_error == 0)
818 s->s_error = sbuf_drain(s);
820 SBUF_SETFLAG(s, SBUF_FINISHED);
824 if (s->s_error != 0) {
833 * Return a pointer to the sbuf data.
836 sbuf_data(struct sbuf *s)
839 assert_sbuf_integrity(s);
840 assert_sbuf_state(s, SBUF_FINISHED);
841 KASSERT(s->s_drain_func == NULL,
842 ("%s makes no sense on sbuf %p with drain", __func__, s));
848 * Return the length of the sbuf data.
851 sbuf_len(struct sbuf *s)
854 assert_sbuf_integrity(s);
855 /* don't care if it's finished or not */
856 KASSERT(s->s_drain_func == NULL,
857 ("%s makes no sense on sbuf %p with drain", __func__, s));
862 /* If finished, nulterm is already in len, else add one. */
863 if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
864 return (s->s_len + 1);
869 * Clear an sbuf, free its buffer if necessary.
872 sbuf_delete(struct sbuf *s)
876 assert_sbuf_integrity(s);
877 /* don't care if it's finished or not */
879 if (SBUF_ISDYNAMIC(s))
881 isdyn = SBUF_ISDYNSTRUCT(s);
882 memset(s, 0, sizeof(*s));
888 * Check if an sbuf has been finished.
891 sbuf_done(const struct sbuf *s)
894 return (SBUF_ISFINISHED(s));
901 sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
904 assert_sbuf_integrity(s);
905 assert_sbuf_state(s, 0);
907 if (!SBUF_ISSECTION(s)) {
908 KASSERT(s->s_sect_len == 0,
909 ("s_sect_len != 0 when starting a section"));
910 if (old_lenp != NULL)
912 s->s_rec_off = s->s_len;
913 SBUF_SETFLAG(s, SBUF_INSECTION);
915 KASSERT(old_lenp != NULL,
916 ("s_sect_len should be saved when starting a subsection"));
917 *old_lenp = s->s_sect_len;
923 * End the section padding to the specified length with the specified
927 sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
931 assert_sbuf_integrity(s);
932 assert_sbuf_state(s, 0);
933 KASSERT(SBUF_ISSECTION(s),
934 ("attempt to end a section when not in a section"));
937 len = roundup(s->s_sect_len, pad) - s->s_sect_len;
938 for (; s->s_error == 0 && len > 0; len--)
943 s->s_rec_off = s->s_sect_len = 0;
944 SBUF_CLEARFLAG(s, SBUF_INSECTION);
946 s->s_sect_len += old_len;