FreeBSD/Linux Kernel Cross Reference
sys/kern/subr_disk_open.c

     /*      $NetBSD: subr_disk_open.c,v 1.15 2020/02/29 14:44:44 mlelstv Exp $      */
     
     /*-
      * Copyright (c) 2006 The NetBSD Foundation, Inc.
      * All rights reserved.
      *
      * Redistribution and use in source and binary forms, with or without
      * modification, are permitted provided that the following conditions
      * are met:
     * 1. Redistributions of source code must retain the above copyright
     *    notice, this list of conditions and the following disclaimer.
     * 2. Redistributions in binary form must reproduce the above copyright
     *    notice, this list of conditions and the following disclaimer in the
     *    documentation and/or other materials provided with the distribution.
     *
     * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     * POSSIBILITY OF SUCH DAMAGE.
     */
    
    #include <sys/cdefs.h>
    __KERNEL_RCSID(0, "$NetBSD: subr_disk_open.c,v 1.15 2020/02/29 14:44:44 mlelstv Exp $");
    
    #include <sys/param.h>
    #include <sys/conf.h>
    #include <sys/device.h>
    #include <sys/disk.h>
    #include <sys/disklabel.h>
    #include <sys/fcntl.h>
    #include <sys/kauth.h>
    #include <sys/vnode.h>
    #include <miscfs/specfs/specdev.h>
    
    struct vnode *
    opendisk(device_t dv)
    {
            devmajor_t bmajor;
            int unit;
            struct vnode *tmpvn;
            int error;
            dev_t dev;
            
            /*
             * Lookup major number for disk block device.
             */
            bmajor = devsw_name2blk(device_xname(dv), NULL, 0);
            if (bmajor == -1)
                    return NULL;
            
            unit = device_unit(dv);
            /*
             * Fake a temporary vnode for the disk, open it, and read
             * and hash the sectors.
             */
            dev = device_is_a(dv, "dk") ? makedev(bmajor, unit) :
                MAKEDISKDEV(bmajor, unit, RAW_PART);
            if (bdevvp(dev, &tmpvn))
                    panic("%s: can't alloc vnode for %s", __func__,
                        device_xname(dv));
            vn_lock(tmpvn, LK_EXCLUSIVE | LK_RETRY);
            error = VOP_OPEN(tmpvn, FREAD | FSILENT, NOCRED);
            if (error) {
                    /*
                     * Ignore errors caused by missing device, partition,
                     * medium, or busy [presumably because of a wedge covering it]
                     */
                    switch (error) {
                    case ENXIO:
                    case ENODEV:
                    case EBUSY:
                            break;
                    default:
                            printf("%s: can't open dev %s (%d)\n",
                                __func__, device_xname(dv), error);
                            break;
                    }
                    vput(tmpvn);
                    return NULL;
            }
    
            return tmpvn;
    }
    
    int
    getdisksize(struct vnode *vp, uint64_t *numsecp, unsigned int *secsizep)
    {
            struct partinfo pi;
            struct dkwedge_info dkw;
            struct disk *pdk;
            unsigned int secsize;
            uint64_t numsec;
           int error;
   
           /*
            * We attempt to get the wedge information first if it exists,
            * because the label does not support larger size disks.
            */
           error = VOP_IOCTL(vp, DIOCGWEDGEINFO, &dkw, FREAD, NOCRED);
           if (error == 0) {
                   pdk = disk_find(dkw.dkw_parent);
                   if (pdk != NULL) {
                           secsize = DEV_BSIZE << pdk->dk_blkshift;
                           numsec  = dkw.dkw_size;
                   } else
                           error = ENODEV;
           }
   
           if (error) {
                   error = VOP_IOCTL(vp, DIOCGPARTINFO, &pi, FREAD, NOCRED);
                   if (error == 0) {
                           secsize = pi.pi_secsize;
                           numsec  = pi.pi_size;
                   }
           }
   
           if (error == 0 &&
               (secsize == 0 || secsize > MAXBSIZE || !powerof2(secsize) ||
                numsec == 0)) {
   #ifdef DIAGNOSTIC
                   printf("%s: %s returns invalid disksize values"
                       " (secsize = %u, numsec = %" PRIu64 ")\n",
                       __func__,
                       devsw_blk2name(major(vp->v_specnode->sn_rdev)),
                       secsize, numsec);
   #endif
                   error = EINVAL;
           }
           if (error == 0) {
                   *secsizep = secsize;
                   *numsecp  = numsec;
           }
   
           return error;
   }
   
   int
   getdiskinfo(struct vnode *vp, struct dkwedge_info *dkw)
   {
           struct partinfo pi;
           int error;
           dev_t dev = vp->v_specnode->sn_rdev;
   
           if (VOP_IOCTL(vp, DIOCGWEDGEINFO, dkw, FREAD, NOCRED) == 0)
                   return 0;
           
           if ((error = VOP_IOCTL(vp, DIOCGPARTINFO, &pi, FREAD, NOCRED)) != 0)
                   return error;
   
           snprintf(dkw->dkw_devname, sizeof(dkw->dkw_devname), "%s%" PRId32 "%c",
               devsw_blk2name(major(dev)), DISKUNIT(dev), (char)DISKPART(dev) +
               'a');
   
           dkw->dkw_wname[0] = '\0';
   
           snprintf(dkw->dkw_parent, sizeof(dkw->dkw_parent), "%s%" PRId32,
               devsw_blk2name(major(dev)), DISKUNIT(dev));
   
           dkw->dkw_size = pi.pi_size;
           dkw->dkw_offset = pi.pi_offset;
           strlcpy(dkw->dkw_ptype, getfstypename(pi.pi_fstype),
               sizeof(dkw->dkw_ptype));
   
           return 0;
   }

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