/* $NetBSD: subr_disk_mbr.c,v 1.18 2006/06/11 23:25:23 christos Exp $ */ /* * Copyright (c) 1982, 1986, 1988 Regents of the University of California. * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * @(#)ufs_disksubr.c 7.16 (Berkeley) 5/4/91 */ /* * Code to find a NetBSD label on a disk that contains an i386 style MBR. * The first NetBSD label found in the 2nd sector of a NetBSD partition * is used. * If we don't find a label searching the MBR, we look at the start of the * disk, if that fails then a label is faked up from the MBR. * * If there isn't a disklabel or anything in the MBR then partition a * is set to cover the whole disk. * Useful for files that contain single filesystems (etc). * * This code will read host endian netbsd labels from little endian MBR. * * Based on the i386 disksubr.c * * Since the mbr only has 32bit fields for sector addresses, we do the same. * * XXX There are potential problems writing labels to disks where there * is only space for 8 netbsd partitions but this code has been compiled * with MAXPARTITIONS=16. */ #include __KERNEL_RCSID(0, "$NetBSD: subr_disk_mbr.c,v 1.18 2006/06/11 23:25:23 christos Exp $"); #include #include #include #include #include #include #include "opt_mbr.h" typedef struct mbr_partition mbr_partition_t; /* * We allocate a buffer 2 sectors large, and look in both.... * That means we find labels written by other ports with different offsets. * LABELSECTOR and LABELOFFSET are only used if the disk doesn't have a label. */ #if LABELSECTOR > 1 || LABELOFFSET > 512 #error Invalid LABELSECTOR or LABELOFFSET #endif #define MBR_LABELSECTOR 1 #define SCAN_CONTINUE 0 #define SCAN_FOUND 1 #define SCAN_ERROR 2 typedef struct mbr_args { struct disklabel *lp; void (*strat)(struct buf *); struct buf *bp; const char *msg; int error; int written; /* number of times we wrote label */ int found_mbr; /* set if disk has a valid mbr */ uint label_sector; /* where we found the label */ int action; #define READ_LABEL 1 #define UPDATE_LABEL 2 #define WRITE_LABEL 3 } mbr_args_t; static int validate_label(mbr_args_t *, uint); static int look_netbsd_part(mbr_args_t *, mbr_partition_t *, int, uint); static int write_netbsd_label(mbr_args_t *, mbr_partition_t *, int, uint); static int read_sector(mbr_args_t *a, uint sector, int count) { struct buf *bp = a->bp; int error; bp->b_blkno = sector; bp->b_bcount = count * a->lp->d_secsize; bp->b_flags = (bp->b_flags & ~(B_WRITE | B_DONE)) | B_READ; bp->b_cylinder = sector / a->lp->d_secpercyl; (*a->strat)(bp); error = biowait(bp); if (error != 0) a->error = error; return error; } /* * Scan MBR for partitions, call 'action' routine for each. */ static int scan_mbr(mbr_args_t *a, int (*actn)(mbr_args_t *, mbr_partition_t *, int, uint)) { mbr_partition_t ptns[MBR_PART_COUNT]; mbr_partition_t *dp; struct mbr_sector *mbr; uint ext_base, this_ext, next_ext; int rval; int i; int j; #ifdef COMPAT_386BSD_MBRPART int dp_386bsd = -1; int ap_386bsd = -1; #endif ext_base = 0; this_ext = 0; for (;;) { if (read_sector(a, this_ext, 1)) { a->msg = "dos partition I/O error"; return SCAN_ERROR; } /* Note: Magic number is little-endian. */ mbr = (void *)a->bp->b_data; if (mbr->mbr_magic != htole16(MBR_MAGIC)) return SCAN_CONTINUE; /* Copy data out of buffer so action can use bp */ memcpy(ptns, &mbr->mbr_parts, sizeof ptns); /* Look for drivers and skip them */ if (ext_base == 0 && ptns[0].mbrp_type == MBR_PTYPE_DM6_DDO) { /* We've found a DM6 DDO partition type (used by * the Ontrack Disk Manager drivers). * * Ensure that there are no other partitions in the * MBR and jump to the real partition table (stored * in the first sector of the second track). */ boolean_t ok = TRUE; for (i = 1; i < MBR_PART_COUNT; i++) if (ptns[i].mbrp_type != MBR_PTYPE_UNUSED) ok = FALSE; if (ok) { this_ext = le32toh(a->lp->d_secpercyl / a->lp->d_ntracks); continue; } } /* look for NetBSD partition */ next_ext = 0; dp = ptns; j = 0; for (i = 0; i < MBR_PART_COUNT; i++, dp++) { if (dp->mbrp_type == MBR_PTYPE_UNUSED) continue; /* Check end of partition is inside disk limits */ if ((uint64_t)ext_base + le32toh(dp->mbrp_start) + le32toh(dp->mbrp_size) > a->lp->d_secperunit) { /* This mbr doesn't look good.... */ a->msg = "mbr partition exceeds disk size"; /* ...but don't report this as an error (yet) */ return SCAN_CONTINUE; } a->found_mbr = 1; if (MBR_IS_EXTENDED(dp->mbrp_type)) { next_ext = le32toh(dp->mbrp_start); continue; } #ifdef COMPAT_386BSD_MBRPART if (dp->mbrp_type == MBR_PTYPE_386BSD) { /* * If more than one matches, take last, * as NetBSD install tool does. */ if (this_ext == 0) { dp_386bsd = i; ap_386bsd = j; } continue; } #endif rval = (*actn)(a, dp, j, this_ext); if (rval != SCAN_CONTINUE) return rval; j++; } if (next_ext == 0) break; if (ext_base == 0) { ext_base = next_ext; next_ext = 0; } next_ext += ext_base; if (next_ext <= this_ext) break; this_ext = next_ext; } #ifdef COMPAT_386BSD_MBRPART if (this_ext == 0 && dp_386bsd != -1) return (*actn)(a, &ptns[dp_386bsd], ap_386bsd, 0); #endif return SCAN_CONTINUE; } /* * Attempt to read a disk label from a device * using the indicated strategy routine. * The label must be partly set up before this: * secpercyl, secsize and anything required for a block i/o read * operation in the driver's strategy/start routines * must be filled in before calling us. * * If dos partition table requested, attempt to load it and * find disklabel inside a DOS partition. Also, if bad block * table needed, attempt to extract it as well. Return buffer * for use in signalling errors if requested. * * Returns null on success and an error string on failure. */ const char * readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, struct cpu_disklabel *osdep) { struct dkbad *bdp; int rval; int i; mbr_args_t a; memset(&a, 0, sizeof a); a.lp = lp; a.strat = strat; a.action = READ_LABEL; /* minimal requirements for architypal disk label */ if (lp->d_secsize == 0) lp->d_secsize = DEV_BSIZE; if (lp->d_secperunit == 0) lp->d_secperunit = 0x1fffffff; lp->d_npartitions = RAW_PART + 1; for (i = 0; i < RAW_PART; i++) { lp->d_partitions[i].p_size = 0; lp->d_partitions[i].p_offset = 0; } if (lp->d_partitions[RAW_PART].p_size == 0) lp->d_partitions[RAW_PART].p_size = lp->d_secperunit; lp->d_partitions[RAW_PART].p_offset = 0; /* * Set partition 'a' to be the whole disk. * Cleared if we find an mbr or a netbsd label. */ lp->d_partitions[0].p_size = lp->d_partitions[RAW_PART].p_size; lp->d_partitions[0].p_fstype = FS_BSDFFS; /* get a buffer and initialize it */ a.bp = geteblk(2 * (int)lp->d_secsize); a.bp->b_dev = dev; if (osdep) /* * Scan mbr searching for netbsd partition and saving * bios partition information to use if the netbsd one * is absent. */ rval = scan_mbr(&a, look_netbsd_part); else rval = SCAN_CONTINUE; if (rval == SCAN_CONTINUE) { /* Look at start of disk */ rval = validate_label(&a, 0); } #if 0 /* * Save sector where we found the label for the 'don't overwrite * the label' check in bounds_check_with_label. */ if (rval == SCAN_FOUND) xxx->label_sector = a.label_sector; #endif /* Obtain bad sector table if requested and present */ if (rval == SCAN_FOUND && osdep && (lp->d_flags & D_BADSECT)) { struct dkbad *db; int blkno; bdp = &osdep->bad; i = 0; rval = SCAN_ERROR; do { /* read a bad sector table */ blkno = lp->d_secperunit - lp->d_nsectors + i; if (lp->d_secsize > DEV_BSIZE) blkno *= lp->d_secsize / DEV_BSIZE; else blkno /= DEV_BSIZE / lp->d_secsize; /* if successful, validate, otherwise try another */ if (read_sector(&a, blkno, 1)) { a.msg = "bad sector table I/O error"; continue; } db = (struct dkbad *)(a.bp->b_data); #define DKBAD_MAGIC 0x4321 if (db->bt_mbz != 0 || db->bt_flag != DKBAD_MAGIC) { a.msg = "bad sector table corrupted"; continue; } rval = SCAN_FOUND; *bdp = *db; break; } while ((a.bp->b_flags & B_ERROR) && (i += 2) < 10 && i < lp->d_nsectors); } brelse(a.bp); if (rval == SCAN_ERROR || rval == SCAN_CONTINUE) return a.msg; return NULL; } static int look_netbsd_part(mbr_args_t *a, mbr_partition_t *dp, int slot, uint ext_base) { struct partition *pp; int ptn_base = ext_base + le32toh(dp->mbrp_start); int rval; if ( #ifdef COMPAT_386BSD_MBRPART dp->mbrp_type == MBR_PTYPE_386BSD || #endif dp->mbrp_type == MBR_PTYPE_NETBSD) { rval = validate_label(a, ptn_base); #if RAW_PART == 3 /* Put actual location where we found the label into ptn 2 */ if (rval == SCAN_FOUND || a->lp->d_partitions[2].p_size == 0) { a->lp->d_partitions[2].p_size = le32toh(dp->mbrp_size); a->lp->d_partitions[2].p_offset = ptn_base; } #endif /* If we got a netbsd label look no further */ if (rval == SCAN_FOUND) return rval; } /* Install main partitions into e..h and extended into i+ */ if (ext_base == 0) slot += 4; else { slot = 4 + MBR_PART_COUNT; pp = &a->lp->d_partitions[slot]; for (; slot < MAXPARTITIONS; pp++, slot++) { /* This gets called twice - avoid duplicates */ if (pp->p_offset == ptn_base && pp->p_size == le32toh(dp->mbrp_size)) break; if (pp->p_size == 0) break; } } if (slot < MAXPARTITIONS) { /* Stop 'a' being the entire disk */ a->lp->d_partitions[0].p_size = 0; a->lp->d_partitions[0].p_fstype = 0; /* save partition info */ pp = &a->lp->d_partitions[slot]; pp->p_offset = ptn_base; pp->p_size = le32toh(dp->mbrp_size); pp->p_fstype = xlat_mbr_fstype(dp->mbrp_type); if (slot >= a->lp->d_npartitions) a->lp->d_npartitions = slot + 1; } return SCAN_CONTINUE; } static int validate_label(mbr_args_t *a, uint label_sector) { struct disklabel *dlp; char *dlp_lim, *dlp_byte; int error; /* Next, dig out disk label */ if (read_sector(a, label_sector, 2)) { a->msg = "disk label read failed"; return SCAN_ERROR; } /* Locate disk label within block and validate */ /* * XXX (dsl) This search may be a waste of time, a lot of other i386 * code assumes the label is at offset LABELOFFSET (=0) in the sector. * * If we want to support disks from other netbsd ports, then the * code should also allow for a shorter label nearer the end of * the disk sector, and (IIRC) labels within 8k of the disk start. */ dlp = (void *)a->bp->b_data; dlp_lim = a->bp->b_data + a->bp->b_bcount - sizeof *dlp; for (;; dlp = (void *)((char *)dlp + sizeof(long))) { if ((char *)dlp > dlp_lim) { if (a->action != WRITE_LABEL) return SCAN_CONTINUE; /* Write at arch. dependant default location */ dlp_byte = a->bp->b_data + LABELOFFSET; if (label_sector) dlp_byte += MBR_LABELSECTOR * a->lp->d_secsize; else dlp_byte += LABELSECTOR * a->lp->d_secsize; dlp = (void *)dlp_byte; break; } if (dlp->d_magic != DISKMAGIC || dlp->d_magic2 != DISKMAGIC) continue; if (dlp->d_npartitions > MAXPARTITIONS || dkcksum(dlp) != 0) { a->msg = "disk label corrupted"; continue; } break; } switch (a->action) { case READ_LABEL: *a->lp = *dlp; a->label_sector = label_sector; return SCAN_FOUND; case UPDATE_LABEL: case WRITE_LABEL: *dlp = *a->lp; a->bp->b_flags &= ~(B_READ|B_DONE); a->bp->b_flags |= B_WRITE; (*a->strat)(a->bp); error = biowait(a->bp); if (error != 0) { a->error = error; a->msg = "disk label write failed"; return SCAN_ERROR; } a->written++; /* Write label to all mbr partitions */ return SCAN_CONTINUE; default: return SCAN_ERROR; } } /* * Check new disk label for sensibility * before setting it. */ int setdisklabel(struct disklabel *olp, struct disklabel *nlp, u_long openmask, struct cpu_disklabel *osdep) { int i; struct partition *opp, *npp; /* sanity clause */ if (nlp->d_secpercyl == 0 || nlp->d_secsize == 0 || (nlp->d_secsize % DEV_BSIZE) != 0) return (EINVAL); /* special case to allow disklabel to be invalidated */ if (nlp->d_magic == 0xffffffff) { *olp = *nlp; return (0); } if (nlp->d_magic != DISKMAGIC || nlp->d_magic2 != DISKMAGIC || dkcksum(nlp) != 0) return (EINVAL); /* XXX missing check if other dos partitions will be overwritten */ while (openmask != 0) { i = ffs(openmask) - 1; openmask &= ~(1 << i); if (i > nlp->d_npartitions) return (EBUSY); opp = &olp->d_partitions[i]; npp = &nlp->d_partitions[i]; /* * Copy internally-set partition information * if new label doesn't include it. XXX */ if (npp->p_fstype == FS_UNUSED && opp->p_fstype != FS_UNUSED) { *npp = *opp; continue; } if (npp->p_offset != opp->p_offset || npp->p_size < opp->p_size) return (EBUSY); } nlp->d_checksum = 0; nlp->d_checksum = dkcksum(nlp); *olp = *nlp; return (0); } /* * Write disk label back to device after modification. */ int writedisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp, struct cpu_disklabel *osdep) { mbr_args_t a; memset(&a, 0, sizeof a); a.lp = lp; a.strat = strat; /* get a buffer and initialize it */ a.bp = geteblk(2 * (int)lp->d_secsize); a.bp->b_dev = dev; /* osdep => we expect an mbr with label in netbsd ptn */ a.action = osdep != NULL ? WRITE_LABEL : UPDATE_LABEL; /* Write/update the label to every netbsd mbr partition */ scan_mbr(&a, write_netbsd_label); /* Old write the label at the start of the volume on disks that * don't have a valid mbr (always update an existing one) */ a.action = a.found_mbr ? UPDATE_LABEL : WRITE_LABEL; validate_label(&a, 0); if (a.written == 0 && a.error == 0) a.error = ESRCH; brelse(a.bp); return a.error; } static int write_netbsd_label(mbr_args_t *a, mbr_partition_t *dp, int slot, uint ext_base) { int ptn_base = ext_base + le32toh(dp->mbrp_start); if (dp->mbrp_type != MBR_PTYPE_NETBSD) return SCAN_CONTINUE; return validate_label(a, ptn_base); } /* * Determine the size of the transfer, and make sure it is * within the boundaries of the partition. Adjust transfer * if needed, and signal errors or early completion. */ int bounds_check_with_label(struct disk *dk, struct buf *bp, int wlabel) { struct disklabel *lp = dk->dk_label; struct partition *p = lp->d_partitions + DISKPART(bp->b_dev); int labelsector = LABELSECTOR; int64_t sz; #if RAW_PART == 3 labelsector += lp->d_partitions[2].p_offset; #endif sz = howmany(bp->b_bcount, lp->d_secsize); if (bp->b_blkno + sz > p->p_size) { sz = p->p_size - bp->b_blkno; if (sz == 0) { /* If exactly at end of disk, return EOF. */ bp->b_resid = bp->b_bcount; return (0); } if (sz < 0) { /* If past end of disk, return EINVAL. */ bp->b_error = EINVAL; goto bad; } /* Otherwise, truncate request. */ bp->b_bcount = sz << DEV_BSHIFT; } /* Overwriting disk label? */ if (bp->b_blkno + p->p_offset <= labelsector && bp->b_blkno + p->p_offset + sz > labelsector && (bp->b_flags & B_READ) == 0 && !wlabel) { bp->b_error = EROFS; goto bad; } /* calculate cylinder for disksort to order transfers with */ bp->b_cylinder = (bp->b_blkno + p->p_offset) / (lp->d_secsize / DEV_BSIZE) / lp->d_secpercyl; return (1); bad: bp->b_flags |= B_ERROR; return (-1); }