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 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
22 /* All Rights Reserved */
23
24
25 /*
26 * Copyright 2009 Sun Microsystems, Inc. All rights reserved.
27 * Use is subject to license terms.
28 *
29 * Copyright 2017 Nexenta Systems, Inc. All rights reserved.
30 */
31
32 /*
33 * UNIX Device Driver Interface functions
34 * (excerpts)
35 */
36
37 #include <sys/types.h>
38 #include <sys/sysmacros.h>
39 #include <sys/param.h>
40 #include <sys/ddi.h>
41 #include <sys/mkdev.h>
42 #include <sys/debug.h>
43
44 #ifndef NODEV32
45 #define NODEV32 (dev32_t)(-1)
46 #endif /* NODEV32 */
47
48 /*
49 * return internal major number corresponding to device
50 * number (new format) argument
51 */
52 major_t
getmajor(dev_t dev)53 getmajor(dev_t dev)
54 {
55 #ifdef _LP64
56 return ((major_t)((dev >> NBITSMINOR64) & MAXMAJ64));
57 #else
58 return ((major_t)((dev >> NBITSMINOR) & MAXMAJ));
59 #endif
60 }
61
62 /*
63 * return internal minor number corresponding to device
64 * number (new format) argument
65 */
66 minor_t
getminor(dev_t dev)67 getminor(dev_t dev)
68 {
69 #ifdef _LP64
70 return ((minor_t)(dev & MAXMIN64));
71 #else
72 return ((minor_t)(dev & MAXMIN));
73 #endif
74 }
75
76 /*
77 * encode external major and minor number arguments into a
78 * new format device number
79 */
80 dev_t
makedevice(major_t maj,minor_t minor)81 makedevice(major_t maj, minor_t minor)
82 {
83 #ifdef _LP64
84 return (((dev_t)maj << NBITSMINOR64) | (minor & MAXMIN64));
85 #else
86 return (((dev_t)maj << NBITSMINOR) | (minor & MAXMIN));
87 #endif
88 }
89
90 /*
91 * Compress 'long' device number encoding to 32-bit device number
92 * encoding. If it won't fit, we return failure, but set the
93 * device number to 32-bit NODEV for the sake of our callers.
94 */
95 int
cmpldev(dev32_t * dst,dev_t dev)96 cmpldev(dev32_t *dst, dev_t dev)
97 {
98 #if defined(_LP64)
99 if (dev == NODEV) {
100 *dst = NODEV32;
101 } else {
102 major_t major = dev >> L_BITSMINOR;
103 minor_t minor = dev & L_MAXMIN;
104
105 if (major > L_MAXMAJ32 || minor > L_MAXMIN32) {
106 *dst = NODEV32;
107 return (0);
108 }
109
110 *dst = (dev32_t)((major << L_BITSMINOR32) | minor);
111 }
112 #else
113 *dst = (dev32_t)dev;
114 #endif
115 return (1);
116 }
117
118 /*
119 * Expand 32-bit dev_t's to long dev_t's. Expansion always "fits"
120 * into the return type, but we're careful to expand NODEV explicitly.
121 */
122 dev_t
expldev(dev32_t dev32)123 expldev(dev32_t dev32)
124 {
125 #ifdef _LP64
126 if (dev32 == NODEV32)
127 return (NODEV);
128 return (makedevice((dev32 >> L_BITSMINOR32) & L_MAXMAJ32,
129 dev32 & L_MAXMIN32));
130 #else
131 return ((dev_t)dev32);
132 #endif
133 }
134