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 /* Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
23 /* All Rights Reserved */
24
25
26 /*
27 * Copyright (c) 1997, by Sun Microsystems, Inc.
28 * All rights reserved.
29 */
30
31 #pragma ident "%Z%%M% %I% %E% SMI" /* SVr4.0 1.2 */
32
33 /*LINTLIBRARY*/
34
35 /*
36 * devattr.c
37 *
38 * Contents:
39 * devattr() Get the value of a attribute for a specific device
40 */
41
42 /*
43 * Header files needed
44 * <sys/types.h> System Data Types
45 * <stdio.h> Standard I/O Definitions
46 * <errno.h> Error-value definitions
47 * <string.h> String function and constant definitions
48 * <devmgmt.h> Device table definitions available to the world
49 * "devtab.h" Local device table definitions
50 */
51
52 #include <sys/types.h>
53 #include <stdio.h>
54 #include <errno.h>
55 #include <string.h>
56 #include <stdlib.h>
57 #include <devmgmt.h>
58 #include "devtab.h"
59
60 /*
61 * Local constant definitions
62 */
63
64
65 /*
66 * Local static data
67 */
68
69 /*
70 * char *devattr(device, attr)
71 *
72 * This function searches the device table, looking for the device
73 * specified by <device>. If it finds a record corresponding to that
74 * device (see below for a definition of that correspondence), it
75 * extracts the value of the field <attr> from that record, if any.
76 * It returns a pointer to that value, or (char *) NULL if none.
77 *
78 * Arguments:
79 * device Pointer to the character-string that describes the
80 * device whose record is to be looked for
81 * attr The device's attribute to be looked for
82 *
83 * Returns: char *
84 * A pointer to the character-string containing the value of the
85 * attribute <attr> for the device <device>, or (char *) NULL if none
86 * was found. If the function returns (char *) NULL and the error was
87 * detected by this function, it sets "errno" to indicate the problem.
88 *
89 * "errno" Values:
90 * EPERM Permissions deny reading access of the device-table
91 * file
92 * ENOENT The specified device-table file could not be found
93 * ENODEV Device not found in the device table
94 * EINVAL The device does not have that attribute defined
95 * ENOMEM No memory available
96 */
97
98 char *
devattr(char * device,char * attribute)99 devattr(
100 char *device, /* The device ) we're to look for */
101 char *attribute) /* The attribute to extract */
102 {
103 /* Automatic data */
104 struct devtabent *record; /* Retrieved record */
105 struct attrval *p; /* attr/val records */
106 char *val; /* Extracted value */
107 char *rtnval; /* Value to return */
108 int found; /* TRUE if attribute found */
109
110
111 /* Get the record for the specified device */
112 if (!(record = _getdevrec(device))) {
113 _enddevtab();
114 return (NULL);
115 }
116
117 /* Search the record for the specified attribute */
118 found = FALSE;
119
120 /* Did they ask for the device alias? */
121 if (strcmp(attribute, DTAB_ALIAS) == 0) {
122 val = (record->alias != NULL) ? record->alias : "";
123 found = TRUE;
124 }
125
126 /* Did they ask for the character-special device? */
127 else if (strcmp(attribute, DTAB_CDEVICE) == 0) {
128 val = (record->cdevice != NULL) ? record->cdevice : "";
129 found = TRUE;
130 }
131
132 /* Did they ask for the block-special device? */
133 else if (strcmp(attribute, DTAB_BDEVICE) == 0) {
134 val = (record->bdevice != NULL) ? record->bdevice : "";
135 found = TRUE;
136 }
137
138 /* Did they ask for the pathname? */
139 else if (strcmp(attribute, DTAB_PATHNAME) == 0) {
140 val = (record->pathname != NULL) ? record->pathname : "";
141 found = TRUE;
142 }
143
144 else {
145
146 /*
147 * Didn't ask for one of the easy ones, search the attr/val
148 * structure
149 */
150
151 p = record->attrlist;
152 while (!found && (p)) {
153 if (strcmp(p->attr, attribute) == 0) {
154 val = p->val;
155 found = TRUE;
156 } else p = p->next;
157 }
158 }
159
160 /*
161 * If the attribute was found, copy it into malloc()ed space.
162 * If not, set errno appropriately; we'll return NULL
163 */
164
165 if (found) {
166 if (rtnval = malloc(strlen(val)+1))
167 (void) strcpy(rtnval, val);
168 else errno = ENOMEM;
169 } else {
170 rtnval = NULL;
171 errno = EINVAL;
172 }
173
174 /* Free the space allocated to the struct devtabent structure */
175 _freedevtabent(record);
176
177 _enddevtab();
178
179 /* Fini */
180 return (rtnval);
181 }
182