xref: /illumos-gate/usr/src/lib/libdevinfo/devinfo_dim.c (revision ddb365bfc9e868ad24ccdcb0dc91af18b10df082)
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 #include "libdevinfo.h"
27 #include <strings.h>
28 #include <sys/modctl.h>
29 
30 /*
31  *
32  * This file contains interfaces to translate <driver><instance><minorname>
33  * information into /devices and /dev paths.  It does this using interfaces to
34  * the kernel instance tree so that it can provide translations for devices
35  * which are no longer present. An example consumer of these interfaces is
36  * iostat(8) - which shows, in its first iteration, activity since reboot.
37  * With persistant kstats, a device which was busy a long time ago can still
38  * have a decaying presence in iostat output, and that output, when '-n' is
39  * used, should show the public name.
40  */
41 
42 typedef	struct {
43 	di_devlink_handle_t	i_devlink_hdl;
44 } *idim_t;
45 
46 di_dim_t
47 di_dim_init()
48 {
49 	idim_t		idim;
50 
51 	if ((idim = (idim_t)malloc(sizeof (*idim))) == NULL)
52 		return (NULL);
53 	idim->i_devlink_hdl = di_devlink_init(NULL, 0);
54 	if (idim->i_devlink_hdl == NULL) {
55 		free(idim);
56 		return (NULL);
57 	}
58 	return ((di_dim_t)idim);
59 }
60 
61 void
62 di_dim_fini(di_dim_t dim)
63 {
64 	idim_t	idim = (idim_t)dim;
65 
66 	if (idim->i_devlink_hdl) {
67 		(void) di_devlink_fini(&idim->i_devlink_hdl);
68 	}
69 	free(idim);
70 }
71 
72 /*ARGSUSED*/
73 char *
74 di_dim_path_devices(di_dim_t dim, char *drv_name, int instance,
75     char *minor_name)
76 {
77 	major_t	major;
78 	int	len;
79 	int	mlen;
80 	char	*devices;
81 
82 	/* convert drv_name to major_t */
83 	if (modctl(MODGETMAJBIND, drv_name, strlen(drv_name) + 1, &major) < 0)
84 		return (NULL);
85 
86 	/* find the length of the devices path given major,instance */
87 	if (modctl(MODGETDEVFSPATH_MI_LEN, major, instance, &len) != 0)
88 		return (NULL);
89 
90 	/*
91 	 * MODGETDEVFSPATH_MI_LEN result includes '\0' termination, but we
92 	 * may need to add space for ":<minor_name>"
93 	 */
94 	if (minor_name)
95 		mlen = len + 1 + strlen(minor_name);
96 	else
97 		mlen = len;
98 	if ((devices = (char *)malloc(mlen)) == NULL)
99 		return (NULL);
100 
101 	if (modctl(MODGETDEVFSPATH_MI, major, instance, len, devices) != 0) {
102 		free(devices);
103 		return (NULL);
104 	}
105 
106 	if (minor_name) {
107 		/* add ':<minot_name>' to the end of /devices path */
108 		(void) strcat(devices, ":");
109 		(void) strcat(devices, minor_name);
110 	}
111 	return (devices);
112 }
113 
114 /* di_dim_path_dev di_devlink callback */
115 static int
116 di_dim_path_dev_callback(di_devlink_t dl, void *arg)
117 {
118 	char		**devp = (char **)arg;
119 	char		*devpath = (char *)di_devlink_path(dl);
120 
121 	if (devpath)
122 		*devp = strdup(devpath);
123 	return (DI_WALK_TERMINATE);
124 }
125 
126 char *
127 di_dim_path_dev(di_dim_t dim, char *drv_name, int instance, char *minor_name)
128 {
129 	idim_t	idim = (idim_t)dim;
130 	char	*devices;
131 	char	*dev = NULL;
132 
133 	/* we must have a minor_name to resolve to a public name */
134 	if (minor_name == NULL)
135 		return (NULL);
136 
137 	/* convert <driver><instance><minor_name> to /devices path */
138 	devices = di_dim_path_devices(dim, drv_name, instance, minor_name);
139 	if (devices == NULL)
140 		return (NULL);
141 
142 	/* convert /devices path to /dev path */
143 	(void) di_devlink_walk(idim->i_devlink_hdl, NULL,
144 	    devices, DI_PRIMARY_LINK, (void *)&dev, di_dim_path_dev_callback);
145 	free(devices);
146 	return (dev);
147 }
148