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 (the "License").
6 * You may not use this file except in compliance with the License.
7 *
8 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9 * or http://www.opensolaris.org/os/licensing.
10 * See the License for the specific language governing permissions
11 * and limitations under the License.
12 *
13 * When distributing Covered Code, include this CDDL HEADER in each
14 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15 * If applicable, add the following below this CDDL HEADER, with the
16 * fields enclosed by brackets "[]" replaced with your own identifying
17 * information: Portions Copyright [yyyy] [name of copyright owner]
18 *
19 * CDDL HEADER END
20 */
21 /*
22 * Copyright 2007 Sun Microsystems, Inc. All rights reserved.
23 * Use is subject to license terms.
24 */
25
26 /*
27 * Memory I/O backend.
28 *
29 * Simple backend that has main memory as its backing store.
30 */
31
32 #include <mdb/mdb_io_impl.h>
33 #include <mdb/mdb.h>
34
35 typedef struct mem_data {
36 char *md_buf;
37 size_t md_size;
38 offset_t md_off;
39 } mem_data_t;
40
41 static ssize_t
memio_read(mdb_io_t * io,void * buf,size_t nbytes)42 memio_read(mdb_io_t *io, void *buf, size_t nbytes)
43 {
44 mem_data_t *mdp = io->io_data;
45
46 if (io->io_next == NULL) {
47 if (mdp->md_off + nbytes > mdp->md_size)
48 nbytes = (mdp->md_size - mdp->md_off);
49 bcopy(mdp->md_buf + mdp->md_off, buf, nbytes);
50 mdp->md_off += nbytes;
51 return (nbytes);
52 }
53
54 return (IOP_READ(io->io_next, buf, nbytes));
55 }
56
57 static off64_t
memio_seek(mdb_io_t * io,off64_t offset,int whence)58 memio_seek(mdb_io_t *io, off64_t offset, int whence)
59 {
60 mem_data_t *mdp = io->io_data;
61
62 if (io->io_next == NULL) {
63 switch (whence) {
64 case SEEK_SET:
65 mdp->md_off = offset;
66 break;
67 case SEEK_CUR:
68 mdp->md_off += offset;
69 break;
70 case SEEK_END:
71 mdp->md_off = mdp->md_size + offset;
72 if (mdp->md_off > mdp->md_size)
73 mdp->md_off = mdp->md_size;
74 break;
75 default:
76 return (-1);
77 }
78
79 return (mdp->md_off);
80 }
81
82 return (IOP_SEEK(io->io_next, offset, whence));
83 }
84
85 static const mdb_io_ops_t memio_ops = {
86 .io_read = memio_read,
87 .io_write = no_io_write,
88 .io_seek = memio_seek,
89 .io_ctl = no_io_ctl,
90 .io_close = no_io_close,
91 .io_name = no_io_name,
92 .io_link = no_io_link,
93 .io_unlink = no_io_unlink,
94 .io_setattr = no_io_setattr,
95 .io_suspend = no_io_suspend,
96 .io_resume = no_io_resume,
97 };
98
99 mdb_io_t *
mdb_memio_create(char * buf,size_t size)100 mdb_memio_create(char *buf, size_t size)
101 {
102 mdb_io_t *io = mdb_alloc(sizeof (mdb_io_t), UM_SLEEP);
103 mem_data_t *mdp = mdb_alloc(sizeof (mem_data_t), UM_SLEEP);
104
105 mdp->md_buf = buf;
106 mdp->md_size = size;
107 mdp->md_off = 0;
108
109 io->io_ops = &memio_ops;
110 io->io_data = mdp;
111 io->io_next = NULL;
112 io->io_refcnt = 0;
113
114 return (io);
115 }
116