xref: /illumos-gate/usr/src/lib/libdevinfo/devinfo_dim.c (revision a08731ec17cb062d80f19791149c20e0f2f43b01)
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 2006 Sun Microsystems, Inc.  All rights reserved.
23  * Use is subject to license terms.
24  */
25 
26 #pragma ident	"%Z%%M%	%I%	%E% SMI"
27 
28 #include "libdevinfo.h"
29 #include <strings.h>
30 #include <sys/modctl.h>
31 
32 /*
33  *
34  * This file contains interfaces to translate <driver><instance><minorname>
35  * information into /devices and /dev paths.  It does this using interfaces to
36  * the kernel instance tree so that it can provide translations for devices
37  * which are no longer present. An example consumer of these interfaces is
38  * iostat(1M) - which shows, in its first iteration, activity since reboot.
39  * With persistant kstats, a device which was busy a long time ago can still
40  * have a decaying presence in iostat output, and that output, when '-n' is
41  * used, should show the public name.
42  */
43 
44 typedef	struct {
45 	di_devlink_handle_t	i_devlink_hdl;
46 } *idim_t;
47 
48 di_dim_t
49 di_dim_init()
50 {
51 	idim_t		idim;
52 
53 	if ((idim = (idim_t)malloc(sizeof (*idim))) == NULL)
54 		return (NULL);
55 	idim->i_devlink_hdl = di_devlink_init(NULL, 0);
56 	if (idim->i_devlink_hdl == NULL) {
57 		free(idim);
58 		return (NULL);
59 	}
60 	return ((di_dim_t)idim);
61 }
62 
63 void
64 di_dim_fini(di_dim_t dim)
65 {
66 	idim_t	idim = (idim_t)dim;
67 
68 	if (idim->i_devlink_hdl) {
69 		(void) di_devlink_fini(&idim->i_devlink_hdl);
70 	}
71 	free(idim);
72 }
73 
74 /*ARGSUSED*/
75 char *
76 di_dim_path_devices(di_dim_t dim, char *drv_name, int instance,
77     char *minor_name)
78 {
79 	major_t	major;
80 	int	len;
81 	int	mlen;
82 	char	*devices;
83 
84 	/* convert drv_name to major_t */
85 	if (modctl(MODGETMAJBIND, drv_name, strlen(drv_name) + 1, &major) < 0)
86 		return (NULL);
87 
88 	/* find the length of the devices path given major,instance */
89 	if (modctl(MODGETDEVFSPATH_MI_LEN, major, instance, &len) != 0)
90 		return (NULL);
91 
92 	/*
93 	 * MODGETDEVFSPATH_MI_LEN result includes '\0' termination, but we
94 	 * may need to add space for ":<minor_name>"
95 	 */
96 	if (minor_name)
97 		mlen = len + 1 + strlen(minor_name);
98 	else
99 		mlen = len;
100 	if ((devices = (char *)malloc(mlen)) == NULL)
101 		return (NULL);
102 
103 	if (modctl(MODGETDEVFSPATH_MI, major, instance, len, devices) != 0) {
104 		free(devices);
105 		return (NULL);
106 	}
107 
108 	if (minor_name) {
109 		/* add ':<minot_name>' to the end of /devices path */
110 		(void) strcat(devices, ":");
111 		(void) strcat(devices, minor_name);
112 	}
113 	return (devices);
114 }
115 
116 /* di_dim_path_dev di_devlink callback */
117 static int
118 di_dim_path_dev_callback(di_devlink_t dl, void *arg)
119 {
120 	char		**devp = (char **)arg;
121 	char		*devpath = (char *)di_devlink_path(dl);
122 
123 	if (devpath)
124 		*devp = strdup(devpath);
125 	return (DI_WALK_TERMINATE);
126 }
127 
128 char *
129 di_dim_path_dev(di_dim_t dim, char *drv_name, int instance, char *minor_name)
130 {
131 	idim_t	idim = (idim_t)dim;
132 	char	*devices;
133 	char	*dev = NULL;
134 
135 	/* we must have a minor_name to resolve to a public name */
136 	if (minor_name == NULL)
137 		return (NULL);
138 
139 	/* convert <driver><instance><minor_name> to /devices path */
140 	devices = di_dim_path_devices(dim, drv_name, instance, minor_name);
141 	if (devices == NULL)
142 		return (NULL);
143 
144 	/* convert /devices path to /dev path */
145 	(void) di_devlink_walk(idim->i_devlink_hdl, NULL,
146 	    devices, DI_PRIMARY_LINK, (void *)&dev, di_dim_path_dev_callback);
147 	free(devices);
148 	return (dev);
149 }
150