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 * String I/O Backend
31 *
32 * Simple backend to provide the ability to perform i/o reads from an in-memory
33 * string.  This allows us to mdb_eval() a string -- by creating an i/o object
34 * out of it, we can then pass it to the parser as stdin.
35 */
36
37#include <mdb/mdb_modapi.h>
38#include <mdb/mdb_io_impl.h>
39#include <mdb/mdb_string.h>
40#include <mdb/mdb_err.h>
41
42typedef struct str_data {
43	char *str_base;		/* Pointer to private copy of string */
44	char *str_ptr;		/* Current seek pointer */
45	size_t str_len;		/* Length of string */
46} str_data_t;
47
48static ssize_t
49strio_read(mdb_io_t *io, void *buf, size_t nbytes)
50{
51	str_data_t *sd = io->io_data;
52	size_t left = sd->str_base + sd->str_len - sd->str_ptr;
53
54	if (left != 0) {
55		size_t obytes = nbytes < left ? nbytes : left;
56		(void) strncpy(buf, sd->str_ptr, obytes);
57		sd->str_ptr += obytes;
58		return (obytes);
59	}
60
61	return (0); /* At end of string: return EOF */
62}
63
64static off64_t
65strio_seek(mdb_io_t *io, off64_t offset, int whence)
66{
67	str_data_t *sd = io->io_data;
68	char *nptr;
69
70	if (io->io_next != NULL)
71		return (IOP_SEEK(io->io_next, offset, whence));
72
73	switch (whence) {
74	case SEEK_SET:
75		nptr = sd->str_base + offset;
76		break;
77	case SEEK_CUR:
78		nptr = sd->str_ptr + offset;
79		break;
80	case SEEK_END:
81		nptr = sd->str_base + sd->str_len + offset;
82		break;
83	default:
84		return (set_errno(EINVAL));
85	}
86
87	if (nptr < sd->str_base || nptr > sd->str_ptr + sd->str_len)
88		return (set_errno(EINVAL));
89
90	sd->str_ptr = nptr;
91	return ((off64_t)(nptr - sd->str_base));
92}
93
94static void
95strio_close(mdb_io_t *io)
96{
97	str_data_t *sd = io->io_data;
98
99	strfree(sd->str_base);
100	mdb_free(sd, sizeof (str_data_t));
101}
102
103static const char *
104strio_name(mdb_io_t *io)
105{
106	if (io->io_next != NULL)
107		return (IOP_NAME(io->io_next));
108
109	return ("(string)");
110}
111
112static const mdb_io_ops_t strio_ops = {
113	strio_read,
114	no_io_write,
115	strio_seek,
116	no_io_ctl,
117	strio_close,
118	strio_name,
119	no_io_link,
120	no_io_unlink,
121	no_io_setattr,
122	no_io_suspend,
123	no_io_resume
124};
125
126mdb_io_t *
127mdb_strio_create(const char *s)
128{
129	mdb_io_t *io = mdb_alloc(sizeof (mdb_io_t), UM_SLEEP);
130	str_data_t *sd = mdb_alloc(sizeof (str_data_t), UM_SLEEP);
131
132	/*
133	 * Our parser expects each command to end with '\n' or ';'.  To
134	 * simplify things for the caller, we append a trailing newline
135	 * so the argvec string can be passed directly sans modifications.
136	 */
137	sd->str_len = strlen(s) + 1;
138	sd->str_base = strndup(s, sd->str_len);
139	(void) strcat(sd->str_base, "\n");
140	sd->str_ptr = sd->str_base;
141
142	io->io_ops = &strio_ops;
143	io->io_data = sd;
144	io->io_next = NULL;
145	io->io_refcnt = 0;
146
147	return (io);
148}
149
150int
151mdb_iob_isastr(mdb_iob_t *iob)
152{
153	mdb_io_t *io;
154
155	for (io = iob->iob_iop; io != NULL; io = io->io_next) {
156		if (io->io_ops == &strio_ops)
157			return (1);
158	}
159
160	return (0);
161}
162