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      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