mdb_logio.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
1/*
2 * CDDL HEADER START
3 *
4 * The contents of this file are subject to the terms of the
5 * Common Development and Distribution License, Version 1.0 only
6 * (the "License").  You may not use this file except in compliance
7 * with the License.
8 *
9 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10 * or http://www.opensolaris.org/os/licensing.
11 * See the License for the specific language governing permissions
12 * and limitations under the License.
13 *
14 * When distributing Covered Code, include this CDDL HEADER in each
15 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16 * If applicable, add the following below this CDDL HEADER, with the
17 * fields enclosed by brackets "[]" replaced with your own identifying
18 * information: Portions Copyright [yyyy] [name of copyright owner]
19 *
20 * CDDL HEADER END
21 */
22/*
23 * Copyright (c) 1997-2001 by Sun Microsystems, Inc.
24 * All rights reserved.
25 */
26
27#pragma ident	"%Z%%M%	%I%	%E% SMI"
28
29/*
30 * Log I/O Backend
31 *
32 * This backend provides the ability to form a T in an iob's output routine.
33 * We use this capability to provide interactive session logging.  We create
34 * a log i/o and give it a pointer to another i/o backend representing the
35 * log file, and then stack this on top of the existing stdio i/o backend.
36 * As each write occurs, the log i/o writes to the log file, and also passes
37 * the write request along to io->io_next.
38 */
39
40#include <mdb/mdb_modapi.h>
41#include <mdb/mdb_err.h>
42#include <mdb/mdb_io_impl.h>
43#include <mdb/mdb.h>
44
45static ssize_t
46logio_read(mdb_io_t *io, void *buf, size_t nbytes)
47{
48	mdb_io_t *logio = io->io_data;
49	ssize_t rbytes;
50
51	if (io->io_next != NULL) {
52		rbytes = IOP_READ(io->io_next, buf, nbytes);
53
54		if (rbytes > 0) {
55			(void) IOP_WRITE(logio, mdb.m_prompt, mdb.m_promptlen);
56			(void) IOP_WRITE(logio, buf, rbytes);
57		}
58
59		return (rbytes);
60	}
61
62	return (-1);
63}
64
65static ssize_t
66logio_write(mdb_io_t *io, const void *buf, size_t nbytes)
67{
68	mdb_io_t *logio = io->io_data;
69	ssize_t wbytes;
70
71	if (io->io_next != NULL) {
72		wbytes = IOP_WRITE(io->io_next, buf, nbytes);
73
74		if (wbytes > 0)
75			(void) IOP_WRITE(logio, buf, wbytes);
76
77		return (wbytes);
78	}
79
80	return (-1);
81}
82
83static void
84logio_close(mdb_io_t *io)
85{
86	mdb_io_rele(io->io_data);
87}
88
89static const char *
90logio_name(mdb_io_t *io)
91{
92	if (io->io_next != NULL)
93		return (IOP_NAME(io->io_next));
94
95	return ("(log)");
96}
97
98static const mdb_io_ops_t logio_ops = {
99	logio_read,
100	logio_write,
101	no_io_seek,
102	no_io_ctl,
103	logio_close,
104	logio_name,
105	no_io_link,
106	no_io_unlink,
107	no_io_setattr,
108	no_io_suspend,
109	no_io_resume
110};
111
112mdb_io_t *
113mdb_logio_create(mdb_io_t *logio)
114{
115	mdb_io_t *io = mdb_alloc(sizeof (mdb_io_t), UM_SLEEP);
116
117	io->io_ops = &logio_ops;
118	io->io_data = mdb_io_hold(logio);
119	io->io_next = NULL;
120	io->io_refcnt = 0;
121
122	return (io);
123}
124