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mirror of https://git.FreeBSD.org/src.git synced 2024-12-14 10:09:48 +00:00
freebsd/sys/kern/subr_sbuf.c
Pedro F. Giffuni 8a36da99de sys/kern: adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 15:20:12 +00:00

885 lines
19 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2000-2008 Poul-Henning Kamp
* Copyright (c) 2000-2008 Dag-Erling Coïdan Smørgrav
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer
* in this position and unchanged.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include <sys/param.h>
#ifdef _KERNEL
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/malloc.h>
#include <sys/systm.h>
#include <sys/uio.h>
#include <machine/stdarg.h>
#else /* _KERNEL */
#include <ctype.h>
#include <errno.h>
#include <limits.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#endif /* _KERNEL */
#include <sys/sbuf.h>
#ifdef _KERNEL
static MALLOC_DEFINE(M_SBUF, "sbuf", "string buffers");
#define SBMALLOC(size) malloc(size, M_SBUF, M_WAITOK|M_ZERO)
#define SBFREE(buf) free(buf, M_SBUF)
#else /* _KERNEL */
#define KASSERT(e, m)
#define SBMALLOC(size) calloc(1, size)
#define SBFREE(buf) free(buf)
#endif /* _KERNEL */
/*
* Predicates
*/
#define SBUF_ISDYNAMIC(s) ((s)->s_flags & SBUF_DYNAMIC)
#define SBUF_ISDYNSTRUCT(s) ((s)->s_flags & SBUF_DYNSTRUCT)
#define SBUF_ISFINISHED(s) ((s)->s_flags & SBUF_FINISHED)
#define SBUF_HASROOM(s) ((s)->s_len < (s)->s_size - 1)
#define SBUF_FREESPACE(s) ((s)->s_size - ((s)->s_len + 1))
#define SBUF_CANEXTEND(s) ((s)->s_flags & SBUF_AUTOEXTEND)
#define SBUF_ISSECTION(s) ((s)->s_flags & SBUF_INSECTION)
#define SBUF_NULINCLUDED(s) ((s)->s_flags & SBUF_INCLUDENUL)
#define SBUF_ISDRAINTOEOR(s) ((s)->s_flags & SBUF_DRAINTOEOR)
#define SBUF_DODRAINTOEOR(s) (SBUF_ISSECTION(s) && SBUF_ISDRAINTOEOR(s))
/*
* Set / clear flags
*/
#define SBUF_SETFLAG(s, f) do { (s)->s_flags |= (f); } while (0)
#define SBUF_CLEARFLAG(s, f) do { (s)->s_flags &= ~(f); } while (0)
#define SBUF_MINSIZE 2 /* Min is 1 byte + nulterm. */
#define SBUF_MINEXTENDSIZE 16 /* Should be power of 2. */
#ifdef PAGE_SIZE
#define SBUF_MAXEXTENDSIZE PAGE_SIZE
#define SBUF_MAXEXTENDINCR PAGE_SIZE
#else
#define SBUF_MAXEXTENDSIZE 4096
#define SBUF_MAXEXTENDINCR 4096
#endif
/*
* Debugging support
*/
#if defined(_KERNEL) && defined(INVARIANTS)
static void
_assert_sbuf_integrity(const char *fun, struct sbuf *s)
{
KASSERT(s != NULL,
("%s called with a NULL sbuf pointer", fun));
KASSERT(s->s_buf != NULL,
("%s called with uninitialized or corrupt sbuf", fun));
if (SBUF_ISFINISHED(s) && SBUF_NULINCLUDED(s)) {
KASSERT(s->s_len <= s->s_size,
("wrote past end of sbuf (%jd >= %jd)",
(intmax_t)s->s_len, (intmax_t)s->s_size));
} else {
KASSERT(s->s_len < s->s_size,
("wrote past end of sbuf (%jd >= %jd)",
(intmax_t)s->s_len, (intmax_t)s->s_size));
}
}
static void
_assert_sbuf_state(const char *fun, struct sbuf *s, int state)
{
KASSERT((s->s_flags & SBUF_FINISHED) == state,
("%s called with %sfinished or corrupt sbuf", fun,
(state ? "un" : "")));
}
#define assert_sbuf_integrity(s) _assert_sbuf_integrity(__func__, (s))
#define assert_sbuf_state(s, i) _assert_sbuf_state(__func__, (s), (i))
#else /* _KERNEL && INVARIANTS */
#define assert_sbuf_integrity(s) do { } while (0)
#define assert_sbuf_state(s, i) do { } while (0)
#endif /* _KERNEL && INVARIANTS */
#ifdef CTASSERT
CTASSERT(powerof2(SBUF_MAXEXTENDSIZE));
CTASSERT(powerof2(SBUF_MAXEXTENDINCR));
#endif
static int
sbuf_extendsize(int size)
{
int newsize;
if (size < (int)SBUF_MAXEXTENDSIZE) {
newsize = SBUF_MINEXTENDSIZE;
while (newsize < size)
newsize *= 2;
} else {
newsize = roundup2(size, SBUF_MAXEXTENDINCR);
}
KASSERT(newsize >= size, ("%s: %d < %d\n", __func__, newsize, size));
return (newsize);
}
/*
* Extend an sbuf.
*/
static int
sbuf_extend(struct sbuf *s, int addlen)
{
char *newbuf;
int newsize;
if (!SBUF_CANEXTEND(s))
return (-1);
newsize = sbuf_extendsize(s->s_size + addlen);
newbuf = SBMALLOC(newsize);
if (newbuf == NULL)
return (-1);
memcpy(newbuf, s->s_buf, s->s_size);
if (SBUF_ISDYNAMIC(s))
SBFREE(s->s_buf);
else
SBUF_SETFLAG(s, SBUF_DYNAMIC);
s->s_buf = newbuf;
s->s_size = newsize;
return (0);
}
/*
* Initialize the internals of an sbuf.
* If buf is non-NULL, it points to a static or already-allocated string
* big enough to hold at least length characters.
*/
static struct sbuf *
sbuf_newbuf(struct sbuf *s, char *buf, int length, int flags)
{
memset(s, 0, sizeof(*s));
s->s_flags = flags;
s->s_size = length;
s->s_buf = buf;
if ((s->s_flags & SBUF_AUTOEXTEND) == 0) {
KASSERT(s->s_size >= SBUF_MINSIZE,
("attempt to create an sbuf smaller than %d bytes",
SBUF_MINSIZE));
}
if (s->s_buf != NULL)
return (s);
if ((flags & SBUF_AUTOEXTEND) != 0)
s->s_size = sbuf_extendsize(s->s_size);
s->s_buf = SBMALLOC(s->s_size);
if (s->s_buf == NULL)
return (NULL);
SBUF_SETFLAG(s, SBUF_DYNAMIC);
return (s);
}
/*
* Initialize an sbuf.
* If buf is non-NULL, it points to a static or already-allocated string
* big enough to hold at least length characters.
*/
struct sbuf *
sbuf_new(struct sbuf *s, char *buf, int length, int flags)
{
KASSERT(length >= 0,
("attempt to create an sbuf of negative length (%d)", length));
KASSERT((flags & ~SBUF_USRFLAGMSK) == 0,
("%s called with invalid flags", __func__));
flags &= SBUF_USRFLAGMSK;
if (s != NULL)
return (sbuf_newbuf(s, buf, length, flags));
s = SBMALLOC(sizeof(*s));
if (s == NULL)
return (NULL);
if (sbuf_newbuf(s, buf, length, flags) == NULL) {
SBFREE(s);
return (NULL);
}
SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
return (s);
}
#ifdef _KERNEL
/*
* Create an sbuf with uio data
*/
struct sbuf *
sbuf_uionew(struct sbuf *s, struct uio *uio, int *error)
{
KASSERT(uio != NULL,
("%s called with NULL uio pointer", __func__));
KASSERT(error != NULL,
("%s called with NULL error pointer", __func__));
s = sbuf_new(s, NULL, uio->uio_resid + 1, 0);
if (s == NULL) {
*error = ENOMEM;
return (NULL);
}
*error = uiomove(s->s_buf, uio->uio_resid, uio);
if (*error != 0) {
sbuf_delete(s);
return (NULL);
}
s->s_len = s->s_size - 1;
if (SBUF_ISSECTION(s))
s->s_sect_len = s->s_size - 1;
*error = 0;
return (s);
}
#endif
int
sbuf_get_flags(struct sbuf *s)
{
return (s->s_flags & SBUF_USRFLAGMSK);
}
void
sbuf_clear_flags(struct sbuf *s, int flags)
{
s->s_flags &= ~(flags & SBUF_USRFLAGMSK);
}
void
sbuf_set_flags(struct sbuf *s, int flags)
{
s->s_flags |= (flags & SBUF_USRFLAGMSK);
}
/*
* Clear an sbuf and reset its position.
*/
void
sbuf_clear(struct sbuf *s)
{
assert_sbuf_integrity(s);
/* don't care if it's finished or not */
SBUF_CLEARFLAG(s, SBUF_FINISHED);
s->s_error = 0;
s->s_len = 0;
s->s_rec_off = 0;
s->s_sect_len = 0;
}
/*
* Set the sbuf's end position to an arbitrary value.
* Effectively truncates the sbuf at the new position.
*/
int
sbuf_setpos(struct sbuf *s, ssize_t pos)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(pos >= 0,
("attempt to seek to a negative position (%jd)", (intmax_t)pos));
KASSERT(pos < s->s_size,
("attempt to seek past end of sbuf (%jd >= %jd)",
(intmax_t)pos, (intmax_t)s->s_size));
KASSERT(!SBUF_ISSECTION(s),
("attempt to seek when in a section"));
if (pos < 0 || pos > s->s_len)
return (-1);
s->s_len = pos;
return (0);
}
/*
* Set up a drain function and argument on an sbuf to flush data to
* when the sbuf buffer overflows.
*/
void
sbuf_set_drain(struct sbuf *s, sbuf_drain_func *func, void *ctx)
{
assert_sbuf_state(s, 0);
assert_sbuf_integrity(s);
KASSERT(func == s->s_drain_func || s->s_len == 0,
("Cannot change drain to %p on non-empty sbuf %p", func, s));
s->s_drain_func = func;
s->s_drain_arg = ctx;
}
/*
* Call the drain and process the return.
*/
static int
sbuf_drain(struct sbuf *s)
{
int len;
KASSERT(s->s_len > 0, ("Shouldn't drain empty sbuf %p", s));
KASSERT(s->s_error == 0, ("Called %s with error on %p", __func__, s));
if (SBUF_DODRAINTOEOR(s) && s->s_rec_off == 0)
return (s->s_error = EDEADLK);
len = s->s_drain_func(s->s_drain_arg, s->s_buf,
SBUF_DODRAINTOEOR(s) ? s->s_rec_off : s->s_len);
if (len <= 0) {
s->s_error = len ? -len : EDEADLK;
return (s->s_error);
}
KASSERT(len > 0 && len <= s->s_len,
("Bad drain amount %d for sbuf %p", len, s));
s->s_len -= len;
s->s_rec_off -= len;
/*
* Fast path for the expected case where all the data was
* drained.
*/
if (s->s_len == 0)
return (0);
/*
* Move the remaining characters to the beginning of the
* string.
*/
memmove(s->s_buf, s->s_buf + len, s->s_len);
return (0);
}
/*
* Append bytes to an sbuf. This is the core function for appending
* to an sbuf and is the main place that deals with extending the
* buffer and marking overflow.
*/
static void
sbuf_put_bytes(struct sbuf *s, const char *buf, size_t len)
{
size_t n;
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
if (s->s_error != 0)
return;
while (len > 0) {
if (SBUF_FREESPACE(s) <= 0) {
/*
* If there is a drain, use it, otherwise extend the
* buffer.
*/
if (s->s_drain_func != NULL)
(void)sbuf_drain(s);
else if (sbuf_extend(s, len > INT_MAX ? INT_MAX : len)
< 0)
s->s_error = ENOMEM;
if (s->s_error != 0)
return;
}
n = SBUF_FREESPACE(s);
if (len < n)
n = len;
memcpy(&s->s_buf[s->s_len], buf, n);
s->s_len += n;
if (SBUF_ISSECTION(s))
s->s_sect_len += n;
len -= n;
buf += n;
}
}
static void
sbuf_put_byte(struct sbuf *s, char c)
{
sbuf_put_bytes(s, &c, 1);
}
/*
* Append a byte string to an sbuf.
*/
int
sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
{
sbuf_put_bytes(s, buf, len);
if (s->s_error != 0)
return (-1);
return (0);
}
#ifdef _KERNEL
/*
* Copy a byte string from userland into an sbuf.
*/
int
sbuf_bcopyin(struct sbuf *s, const void *uaddr, size_t len)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(s->s_drain_func == NULL,
("Nonsensical copyin to sbuf %p with a drain", s));
if (s->s_error != 0)
return (-1);
if (len == 0)
return (0);
if (len > SBUF_FREESPACE(s)) {
sbuf_extend(s, len - SBUF_FREESPACE(s));
if (SBUF_FREESPACE(s) < len)
len = SBUF_FREESPACE(s);
}
if (copyin(uaddr, s->s_buf + s->s_len, len) != 0)
return (-1);
s->s_len += len;
return (0);
}
#endif
/*
* Copy a byte string into an sbuf.
*/
int
sbuf_bcpy(struct sbuf *s, const void *buf, size_t len)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
sbuf_clear(s);
return (sbuf_bcat(s, buf, len));
}
/*
* Append a string to an sbuf.
*/
int
sbuf_cat(struct sbuf *s, const char *str)
{
size_t n;
n = strlen(str);
sbuf_put_bytes(s, str, n);
if (s->s_error != 0)
return (-1);
return (0);
}
#ifdef _KERNEL
/*
* Append a string from userland to an sbuf.
*/
int
sbuf_copyin(struct sbuf *s, const void *uaddr, size_t len)
{
size_t done;
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(s->s_drain_func == NULL,
("Nonsensical copyin to sbuf %p with a drain", s));
if (s->s_error != 0)
return (-1);
if (len == 0)
len = SBUF_FREESPACE(s); /* XXX return 0? */
if (len > SBUF_FREESPACE(s)) {
sbuf_extend(s, len);
if (SBUF_FREESPACE(s) < len)
len = SBUF_FREESPACE(s);
}
switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
case ENAMETOOLONG:
s->s_error = ENOMEM;
/* fall through */
case 0:
s->s_len += done - 1;
if (SBUF_ISSECTION(s))
s->s_sect_len += done - 1;
break;
default:
return (-1); /* XXX */
}
return (done);
}
#endif
/*
* Copy a string into an sbuf.
*/
int
sbuf_cpy(struct sbuf *s, const char *str)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
sbuf_clear(s);
return (sbuf_cat(s, str));
}
/*
* Format the given argument list and append the resulting string to an sbuf.
*/
#ifdef _KERNEL
/*
* Append a non-NUL character to an sbuf. This prototype signature is
* suitable for use with kvprintf(9).
*/
static void
sbuf_putc_func(int c, void *arg)
{
if (c != '\0')
sbuf_put_byte(arg, c);
}
int
sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(fmt != NULL,
("%s called with a NULL format string", __func__));
(void)kvprintf(fmt, sbuf_putc_func, s, 10, ap);
if (s->s_error != 0)
return (-1);
return (0);
}
#else /* !_KERNEL */
int
sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
{
va_list ap_copy;
int error, len;
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(fmt != NULL,
("%s called with a NULL format string", __func__));
if (s->s_error != 0)
return (-1);
/*
* For the moment, there is no way to get vsnprintf(3) to hand
* back a character at a time, to push everything into
* sbuf_putc_func() as was done for the kernel.
*
* In userspace, while drains are useful, there's generally
* not a problem attempting to malloc(3) on out of space. So
* expand a userland sbuf if there is not enough room for the
* data produced by sbuf_[v]printf(3).
*/
error = 0;
do {
va_copy(ap_copy, ap);
len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
fmt, ap_copy);
if (len < 0) {
s->s_error = errno;
return (-1);
}
va_end(ap_copy);
if (SBUF_FREESPACE(s) >= len)
break;
/* Cannot print with the current available space. */
if (s->s_drain_func != NULL && s->s_len > 0)
error = sbuf_drain(s); /* sbuf_drain() sets s_error. */
else if (sbuf_extend(s, len - SBUF_FREESPACE(s)) != 0)
s->s_error = error = ENOMEM;
} while (error == 0);
/*
* s->s_len is the length of the string, without the terminating nul.
* When updating s->s_len, we must subtract 1 from the length that
* we passed into vsnprintf() because that length includes the
* terminating nul.
*
* vsnprintf() returns the amount that would have been copied,
* given sufficient space, so don't over-increment s_len.
*/
if (SBUF_FREESPACE(s) < len)
len = SBUF_FREESPACE(s);
s->s_len += len;
if (SBUF_ISSECTION(s))
s->s_sect_len += len;
KASSERT(s->s_len < s->s_size,
("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));
if (s->s_error != 0)
return (-1);
return (0);
}
#endif /* _KERNEL */
/*
* Format the given arguments and append the resulting string to an sbuf.
*/
int
sbuf_printf(struct sbuf *s, const char *fmt, ...)
{
va_list ap;
int result;
va_start(ap, fmt);
result = sbuf_vprintf(s, fmt, ap);
va_end(ap);
return (result);
}
/*
* Append a character to an sbuf.
*/
int
sbuf_putc(struct sbuf *s, int c)
{
sbuf_put_byte(s, c);
if (s->s_error != 0)
return (-1);
return (0);
}
/*
* Trim whitespace characters from end of an sbuf.
*/
int
sbuf_trim(struct sbuf *s)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(s->s_drain_func == NULL,
("%s makes no sense on sbuf %p with drain", __func__, s));
if (s->s_error != 0)
return (-1);
while (s->s_len > 0 && isspace(s->s_buf[s->s_len-1])) {
--s->s_len;
if (SBUF_ISSECTION(s))
s->s_sect_len--;
}
return (0);
}
/*
* Check if an sbuf has an error.
*/
int
sbuf_error(const struct sbuf *s)
{
return (s->s_error);
}
/*
* Finish off an sbuf.
*/
int
sbuf_finish(struct sbuf *s)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
s->s_buf[s->s_len] = '\0';
if (SBUF_NULINCLUDED(s))
s->s_len++;
if (s->s_drain_func != NULL) {
while (s->s_len > 0 && s->s_error == 0)
s->s_error = sbuf_drain(s);
}
SBUF_SETFLAG(s, SBUF_FINISHED);
#ifdef _KERNEL
return (s->s_error);
#else
if (s->s_error != 0) {
errno = s->s_error;
return (-1);
}
return (0);
#endif
}
/*
* Return a pointer to the sbuf data.
*/
char *
sbuf_data(struct sbuf *s)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, SBUF_FINISHED);
KASSERT(s->s_drain_func == NULL,
("%s makes no sense on sbuf %p with drain", __func__, s));
return (s->s_buf);
}
/*
* Return the length of the sbuf data.
*/
ssize_t
sbuf_len(struct sbuf *s)
{
assert_sbuf_integrity(s);
/* don't care if it's finished or not */
KASSERT(s->s_drain_func == NULL,
("%s makes no sense on sbuf %p with drain", __func__, s));
if (s->s_error != 0)
return (-1);
/* If finished, nulterm is already in len, else add one. */
if (SBUF_NULINCLUDED(s) && !SBUF_ISFINISHED(s))
return (s->s_len + 1);
return (s->s_len);
}
/*
* Clear an sbuf, free its buffer if necessary.
*/
void
sbuf_delete(struct sbuf *s)
{
int isdyn;
assert_sbuf_integrity(s);
/* don't care if it's finished or not */
if (SBUF_ISDYNAMIC(s))
SBFREE(s->s_buf);
isdyn = SBUF_ISDYNSTRUCT(s);
memset(s, 0, sizeof(*s));
if (isdyn)
SBFREE(s);
}
/*
* Check if an sbuf has been finished.
*/
int
sbuf_done(const struct sbuf *s)
{
return (SBUF_ISFINISHED(s));
}
/*
* Start a section.
*/
void
sbuf_start_section(struct sbuf *s, ssize_t *old_lenp)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
if (!SBUF_ISSECTION(s)) {
KASSERT(s->s_sect_len == 0,
("s_sect_len != 0 when starting a section"));
if (old_lenp != NULL)
*old_lenp = -1;
s->s_rec_off = s->s_len;
SBUF_SETFLAG(s, SBUF_INSECTION);
} else {
KASSERT(old_lenp != NULL,
("s_sect_len should be saved when starting a subsection"));
*old_lenp = s->s_sect_len;
s->s_sect_len = 0;
}
}
/*
* End the section padding to the specified length with the specified
* character.
*/
ssize_t
sbuf_end_section(struct sbuf *s, ssize_t old_len, size_t pad, int c)
{
ssize_t len;
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
KASSERT(SBUF_ISSECTION(s),
("attempt to end a section when not in a section"));
if (pad > 1) {
len = roundup(s->s_sect_len, pad) - s->s_sect_len;
for (; s->s_error == 0 && len > 0; len--)
sbuf_put_byte(s, c);
}
len = s->s_sect_len;
if (old_len == -1) {
s->s_rec_off = s->s_sect_len = 0;
SBUF_CLEARFLAG(s, SBUF_INSECTION);
} else {
s->s_sect_len += old_len;
}
if (s->s_error != 0)
return (-1);
return (len);
}