source: vbox/trunk/src/VBox/Devices/Network/slirp/bsd/kern/subr_sbuf.c

/*-
 * Copyright (c) 2000 Poul-Henning Kamp and 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.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 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.
 */

#ifndef VBOX
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/subr_sbuf.c,v 1.30.8.1 2009/04/15 03:14:26 kensmith Exp $");

#include <sys/param.h>

#ifdef _KERNEL
#include <sys/ctype.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 <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)
#define min(x,y)                MIN(x,y)
#endif /* _KERNEL */
#else /* VBOX */
# include <iprt/param.h>
# include <iprt/ctype.h>
# include <slirp.h>
# define SBMALLOC(size) RTMemAlloc((size))
# define SBFREE(buf) RTMemFree((buf))
#endif

/*
 * 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_HASOVERFLOWED(s)   ((s)->s_flags & SBUF_OVERFLOWED)
#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. */
#define SBUF_MAXEXTENDSIZE      PAGE_SIZE
#define SBUF_MAXEXTENDINCR      PAGE_SIZE

/*
 * 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 (%d >= %d)", s->s_len, 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 */

static int
sbuf_extendsize(int size)
{
        int newsize;

        newsize = SBUF_MINEXTENDSIZE;
        while (newsize < size) {
                if (newsize < (int)SBUF_MAXEXTENDSIZE)
                        newsize *= 2;
                else
                        newsize += SBUF_MAXEXTENDINCR;
        }

        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 = (char *)SBMALLOC(newsize);
        if (newbuf == NULL)
                return (-1);
        bcopy(s->s_buf, newbuf, 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 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) {
                s = (struct sbuf *)SBMALLOC(sizeof *s);
                if (s == NULL)
                        return (NULL);
                bzero(s, sizeof *s);
                s->s_flags = flags;
                SBUF_SETFLAG(s, SBUF_DYNSTRUCT);
        } else {
                bzero(s, sizeof *s);
                s->s_flags = flags;
        }
        s->s_size = length;
        if (buf) {
                s->s_buf = buf;
                return (s);
        }
        if (flags & SBUF_AUTOEXTEND)
                s->s_size = sbuf_extendsize(s->s_size);
        s->s_buf = (char *)SBMALLOC(s->s_size);
        if (s->s_buf == NULL) {
                if (SBUF_ISDYNSTRUCT(s))
                        SBFREE(s);
                return (NULL);
        }
        SBUF_SETFLAG(s, SBUF_DYNAMIC);
        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);
        SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
        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, int pos)
{
        assert_sbuf_integrity(s);
        assert_sbuf_state(s, 0);

        KASSERT(pos >= 0,
            ("attempt to seek to a negative position (%d)", pos));
        KASSERT(pos < s->s_size,
            ("attempt to seek past end of sbuf (%d >= %d)", pos, s->s_size));

        if (pos < 0 || pos > s->s_len)
                return (-1);
        s->s_len = pos;
        return (0);
}

/*
 * Append a byte string to an sbuf.
 */
int
sbuf_bcat(struct sbuf *s, const void *buf, size_t len)
{
        const char *str = buf;

        assert_sbuf_integrity(s);
        assert_sbuf_state(s, 0);

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

        for (; len; len--) {
                if (!SBUF_HASROOM(s) && sbuf_extend(s, len) < 0)
                        break;
                s->s_buf[s->s_len++] = *str++;
        }
        if (len) {
                SBUF_SETFLAG(s, SBUF_OVERFLOWED);
                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);

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

        if (len == 0)
                return (0);
        if (len > SBUF_FREESPACE(s)) {
                sbuf_extend(s, len - SBUF_FREESPACE(s));
                len = min(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 (SBUF_HASOVERFLOWED(s))
                return (-1);

        while (*str) {
                if (!SBUF_HASROOM(s) && sbuf_extend(s, strlen(str)) < 0)
                        break;
                s->s_buf[s->s_len++] = *str++;
        }
        if (*str) {
                SBUF_SETFLAG(s, SBUF_OVERFLOWED);
                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);

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

        if (len == 0)
                len = SBUF_FREESPACE(s);        /* XXX return 0? */
        if (len > SBUF_FREESPACE(s)) {
                sbuf_extend(s, len);
                len = min(len, SBUF_FREESPACE(s));
        }
        switch (copyinstr(uaddr, s->s_buf + s->s_len, len + 1, &done)) {
        case ENAMETOOLONG:
                SBUF_SETFLAG(s, SBUF_OVERFLOWED);
                RT_FALL_THRU();
        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.
 */
int
sbuf_vprintf(struct sbuf *s, const char *fmt, va_list ap)
{
        va_list ap_copy;
        int len;

        assert_sbuf_integrity(s);
        assert_sbuf_state(s, 0);

        KASSERT(fmt != NULL,
            ("%s called with a NULL format string", __func__));

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

        do {
                va_copy(ap_copy, ap);
#ifndef VBOX
                len = vsnprintf(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
                    fmt, ap_copy);
#else
                len = RTStrPrintfV(&s->s_buf[s->s_len], SBUF_FREESPACE(s) + 1,
                    fmt, ap_copy);
#endif
                va_end(ap_copy);
        } while (len > SBUF_FREESPACE(s) &&
            sbuf_extend(s, len - SBUF_FREESPACE(s)) == 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, hence the min() calculation below.
         */
        s->s_len += min(len, SBUF_FREESPACE(s));
        if (!SBUF_HASROOM(s) && !SBUF_CANEXTEND(s))
                SBUF_SETFLAG(s, SBUF_OVERFLOWED);

        KASSERT(s->s_len < s->s_size,
            ("wrote past end of sbuf (%d >= %d)", s->s_len, s->s_size));

        if (SBUF_HASOVERFLOWED(s))
                return (-1);
        return (0);
}

/*
 * 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)
{
        assert_sbuf_integrity(s);
        assert_sbuf_state(s, 0);

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

        if (!SBUF_HASROOM(s) && sbuf_extend(s, 1) < 0) {
                SBUF_SETFLAG(s, SBUF_OVERFLOWED);
                return (-1);
        }
        if (c != '\0')
            s->s_buf[s->s_len++] = c;
        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);

        if (SBUF_HASOVERFLOWED(s))
                return (-1);

#ifndef VBOX
        while (s->s_len && isspace(s->s_buf[s->s_len-1]))
                --s->s_len;
#else
        while (s->s_len && RT_C_IS_SPACE(s->s_buf[s->s_len-1]))
                --s->s_len;
#endif

        return (0);
}

/*
 * Check if an sbuf overflowed
 */
int
sbuf_overflowed(struct sbuf *s)
{
    return SBUF_HASOVERFLOWED(s);
}

/*
 * Finish off an sbuf.
 */
void
sbuf_finish(struct sbuf *s)
{
        assert_sbuf_integrity(s);
        assert_sbuf_state(s, 0);

        s->s_buf[s->s_len] = '\0';
        SBUF_CLEARFLAG(s, SBUF_OVERFLOWED);
        SBUF_SETFLAG(s, SBUF_FINISHED);
}

/*
 * Return a pointer to the sbuf data.
 */
char *
sbuf_data(struct sbuf *s)
{
        assert_sbuf_integrity(s);
        assert_sbuf_state(s, SBUF_FINISHED);

        return s->s_buf;
}

/*
 * Return the length of the sbuf data.
 */
int
sbuf_len(struct sbuf *s)
{
        assert_sbuf_integrity(s);
        /* don't care if it's finished or not */

        if (SBUF_HASOVERFLOWED(s))
                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);
        bzero(s, sizeof *s);
        if (isdyn)
                SBFREE(s);
}

/*
 * Check if an sbuf has been finished.
 */
int
sbuf_done(struct sbuf *s)
{

        return(SBUF_ISFINISHED(s));
}