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      1 /*	$NetBSD: subr_disk_open.c,v 1.16 2026/01/04 03:16:38 riastradh Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2006 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  *
     16  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     17  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     18  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     19  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     20  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     21  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     22  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     23  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     24  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     25  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     26  * POSSIBILITY OF SUCH DAMAGE.
     27  */
     28 
     29 #include <sys/cdefs.h>
     30 __KERNEL_RCSID(0, "$NetBSD: subr_disk_open.c,v 1.16 2026/01/04 03:16:38 riastradh Exp $");
     31 
     32 #include <sys/param.h>
     33 
     34 #include <sys/conf.h>
     35 #include <sys/device.h>
     36 #include <sys/disk.h>
     37 #include <sys/disklabel.h>
     38 #include <sys/fcntl.h>
     39 #include <sys/kauth.h>
     40 #include <sys/sdt.h>
     41 #include <sys/vnode.h>
     42 
     43 #include <miscfs/specfs/specdev.h>
     44 
     45 struct vnode *
     46 opendisk(device_t dv)
     47 {
     48 	devmajor_t bmajor;
     49 	int unit;
     50 	struct vnode *tmpvn;
     51 	int error;
     52 	dev_t dev;
     53 
     54 	/*
     55 	 * Lookup major number for disk block device.
     56 	 */
     57 	bmajor = devsw_name2blk(device_xname(dv), NULL, 0);
     58 	if (bmajor == -1)
     59 		return NULL;
     60 
     61 	unit = device_unit(dv);
     62 	/*
     63 	 * Fake a temporary vnode for the disk, open it, and read
     64 	 * and hash the sectors.
     65 	 */
     66 	dev = device_is_a(dv, "dk") ? makedev(bmajor, unit) :
     67 	    MAKEDISKDEV(bmajor, unit, RAW_PART);
     68 	if (bdevvp(dev, &tmpvn))
     69 		panic("%s: can't alloc vnode for %s", __func__,
     70 		    device_xname(dv));
     71 	vn_lock(tmpvn, LK_EXCLUSIVE | LK_RETRY);
     72 	error = VOP_OPEN(tmpvn, FREAD | FSILENT, NOCRED);
     73 	if (error) {
     74 		/*
     75 		 * Ignore errors caused by missing device, partition,
     76 		 * medium, or busy [presumably because of a wedge covering it]
     77 		 */
     78 		switch (error) {
     79 		case ENXIO:
     80 		case ENODEV:
     81 		case EBUSY:
     82 			break;
     83 		default:
     84 			printf("%s: can't open dev %s (%d)\n",
     85 			    __func__, device_xname(dv), error);
     86 			break;
     87 		}
     88 		vput(tmpvn);
     89 		return NULL;
     90 	}
     91 
     92 	return tmpvn;
     93 }
     94 
     95 int
     96 getdisksize(struct vnode *vp, uint64_t *numsecp, unsigned int *secsizep)
     97 {
     98 	struct partinfo pi;
     99 	struct dkwedge_info dkw;
    100 	struct disk *pdk;
    101 	unsigned int secsize;
    102 	uint64_t numsec;
    103 	int error;
    104 
    105 	/*
    106 	 * We attempt to get the wedge information first if it exists,
    107 	 * because the label does not support larger size disks.
    108 	 */
    109 	error = VOP_IOCTL(vp, DIOCGWEDGEINFO, &dkw, FREAD, NOCRED);
    110 	if (error == 0) {
    111 		pdk = disk_find(dkw.dkw_parent);
    112 		if (pdk != NULL) {
    113 			secsize = DEV_BSIZE << pdk->dk_blkshift;
    114 			numsec  = dkw.dkw_size;
    115 		} else
    116 			error = SET_ERROR(ENODEV);
    117 	}
    118 
    119 	if (error) {
    120 		error = VOP_IOCTL(vp, DIOCGPARTINFO, &pi, FREAD, NOCRED);
    121 		if (error == 0) {
    122 			secsize = pi.pi_secsize;
    123 			numsec  = pi.pi_size;
    124 		}
    125 	}
    126 
    127 	if (error == 0 &&
    128 	    (secsize == 0 || secsize > MAXBSIZE || !powerof2(secsize) ||
    129 	     numsec == 0)) {
    130 #ifdef DIAGNOSTIC
    131 		printf("%s: %s returns invalid disksize values"
    132 		    " (secsize = %u, numsec = %" PRIu64 ")\n",
    133 		    __func__,
    134 		    devsw_blk2name(major(vp->v_specnode->sn_rdev)),
    135 		    secsize, numsec);
    136 #endif
    137 		error = SET_ERROR(EINVAL);
    138 	}
    139 	if (error == 0) {
    140 		*secsizep = secsize;
    141 		*numsecp  = numsec;
    142 	}
    143 
    144 	return error;
    145 }
    146 
    147 int
    148 getdiskinfo(struct vnode *vp, struct dkwedge_info *dkw)
    149 {
    150 	struct partinfo pi;
    151 	int error;
    152 	dev_t dev = vp->v_specnode->sn_rdev;
    153 
    154 	if (VOP_IOCTL(vp, DIOCGWEDGEINFO, dkw, FREAD, NOCRED) == 0)
    155 		return 0;
    156 
    157 	if ((error = VOP_IOCTL(vp, DIOCGPARTINFO, &pi, FREAD, NOCRED)) != 0)
    158 		return error;
    159 
    160 	snprintf(dkw->dkw_devname, sizeof(dkw->dkw_devname), "%s%" PRId32 "%c",
    161 	    devsw_blk2name(major(dev)), DISKUNIT(dev), (char)DISKPART(dev) +
    162 	    'a');
    163 
    164 	dkw->dkw_wname[0] = '\0';
    165 
    166 	snprintf(dkw->dkw_parent, sizeof(dkw->dkw_parent), "%s%" PRId32,
    167 	    devsw_blk2name(major(dev)), DISKUNIT(dev));
    168 
    169 	dkw->dkw_size = pi.pi_size;
    170 	dkw->dkw_offset = pi.pi_offset;
    171 	strlcpy(dkw->dkw_ptype, getfstypename(pi.pi_fstype),
    172 	    sizeof(dkw->dkw_ptype));
    173 
    174 	return 0;
    175 }
    176