zfs/tests/zfs-tests/cmd/devname2devid/devname2devid.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 /*
  23  * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  *
  26  * Copyright (c) 2016, Intel Corporation.
  27  */
  28
  29 #include <sys/types.h>
  30 #include <sys/param.h>
  31 #include <sys/stat.h>
  32 #include <libudev.h>
  33 #include <errno.h>
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <fcntl.h>
  38
  39 /*
  40  * Linux persistent device strings for vdev labels
  41  *
  42  * based on udev_device_get_devid() at zfs/lib/libzfs/libzfs_import.c
  43  */
  44
  45 #define DEV_BYID_PATH   "/dev/disk/by-id/"
  46
  47 static int
  48 udev_device_get_devid(struct udev_device *dev, char *bufptr, size_t buflen)
  49 {
  50         struct udev_list_entry *entry;
  51         const char *bus;
  52         char devbyid[MAXPATHLEN];
  53
  54         /* The bus based by-id path is preferred */
  55         bus = udev_device_get_property_value(dev, "ID_BUS");
  56
  57         if (bus == NULL) {
  58                 const char *dm_uuid;
  59
  60                 /*
  61                  * For multipath nodes use the persistent uuid based identifier
  62                  *
  63                  * Example: 'dm-uuid-mpath-35000c5006304de3f'
  64                  */
  65                 dm_uuid = udev_device_get_property_value(dev, "DM_UUID");
  66                 if (dm_uuid != NULL) {
  67                         (void) snprintf(bufptr, buflen, "dm-uuid-%s", dm_uuid);
  68                         return (0);
  69                 }
  70                 return (ENODATA);
  71         }
  72
  73         /*
  74          * locate the bus specific by-id link
  75          *
  76          * Example: 'scsi-MG03SCA300_350000494a8cb3d67-part1'
  77          */
  78         (void) snprintf(devbyid, sizeof (devbyid), "%s%s-", DEV_BYID_PATH, bus);
  79         entry = udev_device_get_devlinks_list_entry(dev);
  80         while (entry != NULL) {
  81                 const char *name;
  82
  83                 name = udev_list_entry_get_name(entry);
  84                 if (strncmp(name, devbyid, strlen(devbyid)) == 0) {
  85                         name += strlen(DEV_BYID_PATH);
  86                         (void) stpncpy(bufptr, name, buflen);
  87                         return (0);
  88                 }
  89                 entry = udev_list_entry_get_next(entry);
  90         }
  91
  92         return (ENODATA);
  93 }
  94
  95 /*
  96  * Usage: devname2devid <devicepath>
  97  *
  98  * Examples:
  99  * # ./devname2devid /dev/sda1
 100  * devid scsi-350000394a8caede4-part1
 101  *
 102  * # ./devname2devid /dev/dm-1
 103  * devid: 'dm-uuid-mpath-35000c5006304de3f'
 104  *
 105  * This program accepts a disk or disk slice path and prints a
 106  * device id.
 107  *
 108  * Exit values:
 109  *      0 - means success
 110  *      1 - means failure
 111  *
 112  */
 113 int
 114 main(int argc, char *argv[])
 115 {
 116         struct udev *udev;
 117         struct udev_device *dev = NULL;
 118         char devid[128], nodepath[MAXPATHLEN];
 119         char *device, *sysname;
 120         int ret;
 121
 122         if (argc == 1) {
 123                 (void) printf("%s <devicepath> [search path]\n", argv[0]);
 124                 exit(1);
 125         }
 126         device = argv[1];
 127
 128         if ((udev = udev_new()) == NULL) {
 129                 perror("udev_new");
 130                 exit(1);
 131         }
 132
 133         /* resolve path to a runtime device node instance */
 134         if (realpath(device, nodepath) == NULL) {
 135                 perror("realpath");
 136                 exit(1);
 137         }
 138         sysname = strrchr(nodepath, '/') + 1;
 139
 140         if ((dev = udev_device_new_from_subsystem_sysname(udev, "block",
 141             sysname)) == NULL) {
 142                 perror(sysname);
 143                 exit(1);
 144         }
 145
 146         if ((ret = udev_device_get_devid(dev, devid, sizeof (devid))) != 0) {
 147                 udev_device_unref(dev);
 148                 errno = ret;
 149                 perror(sysname);
 150                 exit(1);
 151         }
 152
 153         (void) printf("devid %s\n", devid);
 154
 155         udev_device_unref(dev);
 156         udev_unref(udev);
 157
 158         return (0);
 159 }