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FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
| Current File : //sys/kern/subr_sbuf.c |
/*-
* 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: release/9.1.0/sys/kern/subr_sbuf.c 224999 2011-08-19 08:29:10Z rwatson $");
#include <sys/param.h>
#ifdef _KERNEL
#include <sys/ctype.h>
#include <sys/errno.h>
#include <sys/kernel.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 <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)
#define SBFREE(buf) free(buf, M_SBUF)
#else /* _KERNEL */
#define KASSERT(e, m)
#define SBMALLOC(size) malloc(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)
/*
* 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_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));
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 >= 0,
("attempt to create a too small sbuf"));
}
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;
*error = 0;
return (s);
}
#endif
/*
* 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;
}
/*
* 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));
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));
len = s->s_drain_func(s->s_drain_arg, s->s_buf, s->s_len);
if (len < 0) {
s->s_error = -len;
return (s->s_error);
}
KASSERT(len > 0 && len <= s->s_len,
("Bad drain amount %d for sbuf %p", len, s));
s->s_len -= 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 a byte 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_byte(struct sbuf *s, int c)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
if (s->s_error != 0)
return;
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, 1) < 0)
s->s_error = ENOMEM;
if (s->s_error != 0)
return;
}
s->s_buf[s->s_len++] = c;
}
/*
* Append a byte string to an sbuf.
*/
int
sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
{
const char *str = buf;
const char *end = str + len;
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
if (s->s_error != 0)
return (-1);
for (; str < end; str++) {
sbuf_put_byte(s, *str);
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)
{
assert_sbuf_integrity(s);
assert_sbuf_state(s, 0);
if (s->s_error != 0)
return (-1);
while (*str != '\0') {
sbuf_put_byte(s, *str++);
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;
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);
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);
else
error = sbuf_extend(s, len - SBUF_FREESPACE(s));
} 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_HASROOM(s) && !SBUF_CANEXTEND(s))
s->s_error = ENOMEM;
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;
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);
if (s->s_drain_func != NULL) {
while (s->s_len > 0 && s->s_error == 0)
s->s_error = sbuf_drain(s);
}
s->s_buf[s->s_len] = '\0';
SBUF_SETFLAG(s, SBUF_FINISHED);
#ifdef _KERNEL
return (s->s_error);
#else
errno = s->s_error;
if (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);
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));
}