FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/tests/zfs-tests/cmd/devname2devid.c

     /*
      * CDDL HEADER START
      *
      * The contents of this file are subject to the terms of the
      * Common Development and Distribution License (the "License").
      * You may not use this file except in compliance with the License.
      *
      * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
      * or https://opensource.org/licenses/CDDL-1.0.
     * See the License for the specific language governing permissions
     * and limitations under the License.
     *
     * When distributing Covered Code, include this CDDL HEADER in each
     * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     * If applicable, add the following below this CDDL HEADER, with the
     * fields enclosed by brackets "[]" replaced with your own identifying
     * information: Portions Copyright [yyyy] [name of copyright owner]
     *
     * CDDL HEADER END
     */
    
    /*
     * Copyright 2007 Sun Microsystems, Inc.  All rights reserved.
     * Use is subject to license terms.
     *
     * Copyright (c) 2016, Intel Corporation.
     */
    
    #include <sys/types.h>
    #include <sys/param.h>
    #include <sys/stat.h>
    #include <libudev.h>
    #include <errno.h>
    #include <stdio.h>
    #include <stdlib.h>
    #include <string.h>
    #include <fcntl.h>
    
    /*
     * Linux persistent device strings for vdev labels
     *
     * based on udev_device_get_devid() at zfs/lib/libzfs/libzfs_import.c
     */
    
    #define DEV_BYID_PATH   "/dev/disk/by-id/"
    
    static int
    udev_device_get_devid(struct udev_device *dev, char *bufptr, size_t buflen)
    {
            struct udev_list_entry *entry;
            const char *bus;
            char devbyid[MAXPATHLEN];
    
            /* The bus based by-id path is preferred */
            bus = udev_device_get_property_value(dev, "ID_BUS");
    
            if (bus == NULL) {
                    const char *dm_uuid;
    
                    /*
                     * For multipath nodes use the persistent uuid based identifier
                     *
                     * Example: 'dm-uuid-mpath-35000c5006304de3f'
                     */
                    dm_uuid = udev_device_get_property_value(dev, "DM_UUID");
                    if (dm_uuid != NULL) {
                            (void) snprintf(bufptr, buflen, "dm-uuid-%s", dm_uuid);
                            return (0);
                    }
                    return (ENODATA);
            }
    
            /*
             * locate the bus specific by-id link
             *
             * Example: 'scsi-MG03SCA300_350000494a8cb3d67-part1'
             */
            (void) snprintf(devbyid, sizeof (devbyid), "%s%s-", DEV_BYID_PATH, bus);
            entry = udev_device_get_devlinks_list_entry(dev);
            while (entry != NULL) {
                    const char *name;
    
                    name = udev_list_entry_get_name(entry);
                    if (strncmp(name, devbyid, strlen(devbyid)) == 0) {
                            name += strlen(DEV_BYID_PATH);
                            (void) stpncpy(bufptr, name, buflen - 1);
                            bufptr[buflen - 1] = '\0';
                            return (0);
                    }
                    entry = udev_list_entry_get_next(entry);
            }
    
            return (ENODATA);
    }
    
    /*
     * Usage: devname2devid <devicepath>
     *
     * Examples:
    * # ./devname2devid /dev/sda1
    * devid scsi-350000394a8caede4-part1
    *
    * # ./devname2devid /dev/dm-1
    * devid: 'dm-uuid-mpath-35000c5006304de3f'
    *
    * This program accepts a disk or disk slice path and prints a
    * device id.
    *
    * Exit values:
    *      0 - means success
    *      1 - means failure
    *
    */
   int
   main(int argc, char *argv[])
   {
           struct udev *udev;
           struct udev_device *dev = NULL;
           char devid[128], nodepath[MAXPATHLEN];
           char *device, *sysname;
           int ret;
   
           if (argc == 1) {
                   (void) printf("%s <devicepath> [search path]\n", argv[0]);
                   exit(1);
           }
           device = argv[1];
   
           if ((udev = udev_new()) == NULL) {
                   perror("udev_new");
                   exit(1);
           }
   
           /* resolve path to a runtime device node instance */
           if (realpath(device, nodepath) == NULL) {
                   perror("realpath");
                   exit(1);
           }
           sysname = strrchr(nodepath, '/') + 1;
   
           if ((dev = udev_device_new_from_subsystem_sysname(udev, "block",
               sysname)) == NULL) {
                   perror(sysname);
                   exit(1);
           }
   
           if ((ret = udev_device_get_devid(dev, devid, sizeof (devid))) != 0) {
                   udev_device_unref(dev);
                   errno = ret;
                   perror(sysname);
                   exit(1);
           }
   
           (void) printf("devid %s\n", devid);
   
           udev_device_unref(dev);
           udev_unref(udev);
   
           return (0);
   }

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