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-rw-r--r--lib/libdtrace/common/dt_buf.c177
1 files changed, 177 insertions, 0 deletions
diff --git a/lib/libdtrace/common/dt_buf.c b/lib/libdtrace/common/dt_buf.c
new file mode 100644
index 000000000000..324e778213ca
--- /dev/null
+++ b/lib/libdtrace/common/dt_buf.c
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+/*
+ * CDDL HEADER START
+ *
+ * The contents of this file are subject to the terms of the
+ * Common Development and Distribution License, Version 1.0 only
+ * (the "License"). You may not use this file except in compliance
+ * with the License.
+ *
+ * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
+ * or http://www.opensolaris.org/os/licensing.
+ * See the License for the specific language governing permissions
+ * and limitations under the License.
+ *
+ * When distributing Covered Code, include this CDDL HEADER in each
+ * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
+ * If applicable, add the following below this CDDL HEADER, with the
+ * fields enclosed by brackets "[]" replaced with your own identifying
+ * information: Portions Copyright [yyyy] [name of copyright owner]
+ *
+ * CDDL HEADER END
+ */
+/*
+ * Copyright 2005 Sun Microsystems, Inc. All rights reserved.
+ * Use is subject to license terms.
+ */
+
+#pragma ident "%Z%%M% %I% %E% SMI"
+
+/*
+ * DTrace Memory Buffer Routines
+ *
+ * The routines in this file are used to create an automatically resizing
+ * memory buffer that can be written to like a file. Memory buffers are
+ * used to construct DOF to ioctl() to dtrace(7D), and provide semantics that
+ * simplify caller code. Specifically, any allocation errors result in an
+ * error code being set inside the buffer which is maintained persistently and
+ * propagates to another buffer if the buffer in error is concatenated. These
+ * semantics permit callers to execute a large series of writes without needing
+ * to check for errors and then perform a single check before using the buffer.
+ */
+
+#include <sys/sysmacros.h>
+#include <strings.h>
+
+#include <dt_impl.h>
+#include <dt_buf.h>
+
+void
+dt_buf_create(dtrace_hdl_t *dtp, dt_buf_t *bp, const char *name, size_t len)
+{
+ if (len == 0)
+ len = _dtrace_bufsize;
+
+ bp->dbu_buf = bp->dbu_ptr = dt_zalloc(dtp, len);
+ bp->dbu_len = len;
+
+ if (bp->dbu_buf == NULL)
+ bp->dbu_err = dtrace_errno(dtp);
+ else
+ bp->dbu_err = 0;
+
+ bp->dbu_resizes = 0;
+ bp->dbu_name = name;
+}
+
+void
+dt_buf_destroy(dtrace_hdl_t *dtp, dt_buf_t *bp)
+{
+ dt_dprintf("dt_buf_destroy(%s): size=%lu resizes=%u\n",
+ bp->dbu_name, (ulong_t)bp->dbu_len, bp->dbu_resizes);
+
+ dt_free(dtp, bp->dbu_buf);
+}
+
+void
+dt_buf_reset(dtrace_hdl_t *dtp, dt_buf_t *bp)
+{
+ if ((bp->dbu_ptr = bp->dbu_buf) != NULL)
+ bp->dbu_err = 0;
+ else
+ dt_buf_create(dtp, bp, bp->dbu_name, bp->dbu_len);
+}
+
+void
+dt_buf_write(dtrace_hdl_t *dtp, dt_buf_t *bp,
+ const void *buf, size_t len, size_t align)
+{
+ size_t off = (size_t)(bp->dbu_ptr - bp->dbu_buf);
+ size_t adj = roundup(off, align) - off;
+
+ if (bp->dbu_err != 0) {
+ (void) dt_set_errno(dtp, bp->dbu_err);
+ return; /* write silently fails */
+ }
+
+ if (bp->dbu_ptr + adj + len > bp->dbu_buf + bp->dbu_len) {
+ size_t new_len = bp->dbu_len * 2;
+ uchar_t *new_buf;
+ uint_t r = 1;
+
+ while (bp->dbu_ptr + adj + len > bp->dbu_buf + new_len) {
+ new_len *= 2;
+ r++;
+ }
+
+ if ((new_buf = dt_zalloc(dtp, new_len)) == NULL) {
+ bp->dbu_err = dtrace_errno(dtp);
+ return;
+ }
+
+ bcopy(bp->dbu_buf, new_buf, off);
+ dt_free(dtp, bp->dbu_buf);
+
+ bp->dbu_buf = new_buf;
+ bp->dbu_ptr = new_buf + off;
+ bp->dbu_len = new_len;
+ bp->dbu_resizes += r;
+ }
+
+ bp->dbu_ptr += adj;
+ bcopy(buf, bp->dbu_ptr, len);
+ bp->dbu_ptr += len;
+}
+
+void
+dt_buf_concat(dtrace_hdl_t *dtp, dt_buf_t *dst,
+ const dt_buf_t *src, size_t align)
+{
+ if (dst->dbu_err == 0 && src->dbu_err != 0) {
+ (void) dt_set_errno(dtp, src->dbu_err);
+ dst->dbu_err = src->dbu_err;
+ } else {
+ dt_buf_write(dtp, dst, src->dbu_buf,
+ (size_t)(src->dbu_ptr - src->dbu_buf), align);
+ }
+}
+
+size_t
+dt_buf_offset(const dt_buf_t *bp, size_t align)
+{
+ size_t off = (size_t)(bp->dbu_ptr - bp->dbu_buf);
+ return (roundup(off, align));
+}
+
+size_t
+dt_buf_len(const dt_buf_t *bp)
+{
+ return (bp->dbu_ptr - bp->dbu_buf);
+}
+
+int
+dt_buf_error(const dt_buf_t *bp)
+{
+ return (bp->dbu_err);
+}
+
+void *
+dt_buf_ptr(const dt_buf_t *bp)
+{
+ return (bp->dbu_buf);
+}
+
+void *
+dt_buf_claim(dtrace_hdl_t *dtp, dt_buf_t *bp)
+{
+ void *buf = bp->dbu_buf;
+
+ if (bp->dbu_err != 0) {
+ dt_free(dtp, buf);
+ buf = NULL;
+ }
+
+ bp->dbu_buf = bp->dbu_ptr = NULL;
+ bp->dbu_len = 0;
+
+ return (buf);
+}