178 lines
4.1 KiB
C
178 lines
4.1 KiB
C
/*
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* CDDL HEADER START
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*
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* The contents of this file are subject to the terms of the
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* Common Development and Distribution License, Version 1.0 only
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* (the "License"). You may not use this file except in compliance
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* with the License.
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*
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* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
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* or http://www.opensolaris.org/os/licensing.
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* See the License for the specific language governing permissions
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* and limitations under the License.
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*
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* When distributing Covered Code, include this CDDL HEADER in each
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* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
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* If applicable, add the following below this CDDL HEADER, with the
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* fields enclosed by brackets "[]" replaced with your own identifying
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* information: Portions Copyright [yyyy] [name of copyright owner]
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*
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* CDDL HEADER END
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*/
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/*
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* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
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* Use is subject to license terms.
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*/
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#pragma ident "%Z%%M% %I% %E% SMI"
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/*
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* DTrace Memory Buffer Routines
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*
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* The routines in this file are used to create an automatically resizing
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* memory buffer that can be written to like a file. Memory buffers are
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* used to construct DOF to ioctl() to dtrace(7D), and provide semantics that
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* simplify caller code. Specifically, any allocation errors result in an
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* error code being set inside the buffer which is maintained persistently and
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* propagates to another buffer if the buffer in error is concatenated. These
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* semantics permit callers to execute a large series of writes without needing
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* to check for errors and then perform a single check before using the buffer.
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*/
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#include <sys/sysmacros.h>
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#include <strings.h>
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#include <dt_impl.h>
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#include <dt_buf.h>
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void
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dt_buf_create(dtrace_hdl_t *dtp, dt_buf_t *bp, const char *name, size_t len)
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{
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if (len == 0)
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len = _dtrace_bufsize;
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bp->dbu_buf = bp->dbu_ptr = dt_zalloc(dtp, len);
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bp->dbu_len = len;
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if (bp->dbu_buf == NULL)
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bp->dbu_err = dtrace_errno(dtp);
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else
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bp->dbu_err = 0;
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bp->dbu_resizes = 0;
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bp->dbu_name = name;
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}
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void
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dt_buf_destroy(dtrace_hdl_t *dtp, dt_buf_t *bp)
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{
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dt_dprintf("dt_buf_destroy(%s): size=%lu resizes=%u\n",
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bp->dbu_name, (ulong_t)bp->dbu_len, bp->dbu_resizes);
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dt_free(dtp, bp->dbu_buf);
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}
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void
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dt_buf_reset(dtrace_hdl_t *dtp, dt_buf_t *bp)
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{
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if ((bp->dbu_ptr = bp->dbu_buf) != NULL)
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bp->dbu_err = 0;
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else
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dt_buf_create(dtp, bp, bp->dbu_name, bp->dbu_len);
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}
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void
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dt_buf_write(dtrace_hdl_t *dtp, dt_buf_t *bp,
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const void *buf, size_t len, size_t align)
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{
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size_t off = (size_t)(bp->dbu_ptr - bp->dbu_buf);
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size_t adj = roundup(off, align) - off;
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if (bp->dbu_err != 0) {
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(void) dt_set_errno(dtp, bp->dbu_err);
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return; /* write silently fails */
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}
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if (bp->dbu_ptr + adj + len > bp->dbu_buf + bp->dbu_len) {
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size_t new_len = bp->dbu_len * 2;
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uchar_t *new_buf;
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uint_t r = 1;
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while (bp->dbu_ptr + adj + len > bp->dbu_buf + new_len) {
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new_len *= 2;
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r++;
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}
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if ((new_buf = dt_zalloc(dtp, new_len)) == NULL) {
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bp->dbu_err = dtrace_errno(dtp);
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return;
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}
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bcopy(bp->dbu_buf, new_buf, off);
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dt_free(dtp, bp->dbu_buf);
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bp->dbu_buf = new_buf;
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bp->dbu_ptr = new_buf + off;
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bp->dbu_len = new_len;
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bp->dbu_resizes += r;
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}
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bp->dbu_ptr += adj;
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bcopy(buf, bp->dbu_ptr, len);
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bp->dbu_ptr += len;
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}
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void
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dt_buf_concat(dtrace_hdl_t *dtp, dt_buf_t *dst,
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const dt_buf_t *src, size_t align)
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{
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if (dst->dbu_err == 0 && src->dbu_err != 0) {
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(void) dt_set_errno(dtp, src->dbu_err);
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dst->dbu_err = src->dbu_err;
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} else {
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dt_buf_write(dtp, dst, src->dbu_buf,
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(size_t)(src->dbu_ptr - src->dbu_buf), align);
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}
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}
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size_t
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dt_buf_offset(const dt_buf_t *bp, size_t align)
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{
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size_t off = (size_t)(bp->dbu_ptr - bp->dbu_buf);
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return (roundup(off, align));
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}
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size_t
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dt_buf_len(const dt_buf_t *bp)
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{
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return (bp->dbu_ptr - bp->dbu_buf);
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}
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int
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dt_buf_error(const dt_buf_t *bp)
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{
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return (bp->dbu_err);
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}
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void *
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dt_buf_ptr(const dt_buf_t *bp)
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{
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return (bp->dbu_buf);
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}
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void *
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dt_buf_claim(dtrace_hdl_t *dtp, dt_buf_t *bp)
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{
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void *buf = bp->dbu_buf;
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if (bp->dbu_err != 0) {
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dt_free(dtp, buf);
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buf = NULL;
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}
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bp->dbu_buf = bp->dbu_ptr = NULL;
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bp->dbu_len = 0;
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return (buf);
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}
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