usr/src/lib/libdevinfo/devinfo_dim.c

   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 }