/* $OpenBSD: mbr.c,v 1.40 2014/05/21 15:55:19 krw Exp $ */ /* * Copyright (c) 1997 Tobias Weingartner * 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 AUTHOR ``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 AUTHOR 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include "disk.h" #include "part.h" #include "misc.h" #include "mbr.h" void MBR_init(struct disk *disk, struct mbr *mbr) { daddr_t i; u_int64_t adj; /* Fix up given mbr for this disk */ mbr->part[0].flag = 0; mbr->part[1].flag = 0; mbr->part[2].flag = 0; mbr->part[3].flag = DOSACTIVE; mbr->signature = DOSMBR_SIGNATURE; /* Use whole disk. Reserve first track, or first cyl, if possible. */ mbr->part[3].id = DOSPTYP_OPENBSD; if (disk->heads > 1) mbr->part[3].shead = 1; else mbr->part[3].shead = 0; if (disk->heads < 2 && disk->cylinders > 1) mbr->part[3].scyl = 1; else mbr->part[3].scyl = 0; mbr->part[3].ssect = 1; /* Go right to the end */ mbr->part[3].ecyl = disk->cylinders - 1; mbr->part[3].ehead = disk->heads - 1; mbr->part[3].esect = disk->sectors; /* Fix up start/length fields */ PRT_fix_BN(disk, &mbr->part[3], 3); #if defined(__powerpc__) || defined(__mips__) /* Now fix up for the MS-DOS boot partition on PowerPC. */ mbr->part[0].flag = DOSACTIVE; /* Boot from dos part */ mbr->part[3].flag = 0; mbr->part[3].ns += mbr->part[3].bs; mbr->part[3].bs = mbr->part[0].bs + mbr->part[0].ns; mbr->part[3].ns -= mbr->part[3].bs; PRT_fix_CHS(disk, &mbr->part[3]); if ((mbr->part[3].shead != 1) || (mbr->part[3].ssect != 1)) { /* align the partition on a cylinder boundary */ mbr->part[3].shead = 0; mbr->part[3].ssect = 1; mbr->part[3].scyl += 1; } /* Fix up start/length fields */ PRT_fix_BN(disk, &mbr->part[3], 3); #endif /* Start OpenBSD MBR partition on a power of 2 block number. */ i = 1; while (i < DL_SECTOBLK(&dl, mbr->part[3].bs)) i *= 2; adj = DL_BLKTOSEC(&dl, i) - mbr->part[3].bs; mbr->part[3].bs += adj; mbr->part[3].ns -= adj; PRT_fix_CHS(disk, &mbr->part[3]); } void MBR_parse(struct disk *disk, struct dos_mbr *dos_mbr, off_t offset, off_t reloff, struct mbr *mbr) { struct dos_partition dos_parts[NDOSPART]; int i; memcpy(mbr->code, dos_mbr->dmbr_boot, sizeof(mbr->code)); mbr->offset = offset; mbr->reloffset = reloff; mbr->signature = letoh16(dos_mbr->dmbr_sign); memcpy(dos_parts, dos_mbr->dmbr_parts, sizeof(dos_parts)); for (i = 0; i < NDOSPART; i++) PRT_parse(disk, &dos_parts[i], offset, reloff, &mbr->part[i]); } void MBR_make(struct mbr *mbr, struct dos_mbr *dos_mbr) { struct dos_partition dos_partition; int i; memcpy(dos_mbr->dmbr_boot, mbr->code, sizeof(dos_mbr->dmbr_boot)); dos_mbr->dmbr_sign = htole16(DOSMBR_SIGNATURE); for (i = 0; i < NDOSPART; i++) { PRT_make(&mbr->part[i], mbr->offset, mbr->reloffset, &dos_partition); memcpy(&dos_mbr->dmbr_parts[i], &dos_partition, sizeof(dos_mbr->dmbr_parts[i])); } } void MBR_print(struct mbr *mbr, char *units) { int i; /* Header */ printf("Signature: 0x%X\n", (int)mbr->signature); PRT_print(0, NULL, units); /* Entries */ for (i = 0; i < NDOSPART; i++) PRT_print(i, &mbr->part[i], units); } int MBR_read(int fd, off_t where, struct dos_mbr *dos_mbr) { const int secsize = unit_types[SECTORS].conversion; ssize_t len; off_t off; char *secbuf; where *= secsize; off = lseek(fd, where, SEEK_SET); if (off != where) return (-1); secbuf = calloc(1, secsize); if (secbuf == NULL) return (-1); len = read(fd, secbuf, secsize); memcpy(dos_mbr, secbuf, sizeof(*dos_mbr)); free(secbuf); if (len == -1) return (-1); if (len < sizeof(*dos_mbr)) { /* short read */ errno = EIO; return (-1); } return (0); } int MBR_write(int fd, off_t where, struct dos_mbr *dos_mbr) { const int secsize = unit_types[SECTORS].conversion; ssize_t len; off_t off; char *secbuf; /* Read the sector we want to store the MBR in. */ where *= secsize; off = lseek(fd, where, SEEK_SET); if (off != where) return (-1); secbuf = calloc(1, secsize); if (secbuf == NULL) return (-1); len = read(fd, secbuf, secsize); if (len == -1 || len != secsize) goto done; /* * Place the new MBR at the start of the sector and * write the sector back to "disk". */ memcpy(secbuf, dos_mbr, sizeof(*dos_mbr)); off = lseek(fd, where, SEEK_SET); if (off == where) len = write(fd, secbuf, secsize); else len = -1; done: free(secbuf); if (len == -1) return (-1); if (len != secsize) { /* short read or write */ errno = EIO; return (-1); } ioctl(fd, DIOCRLDINFO, 0); return (0); } /* * Parse the MBR partition table into 'mbr', leaving the rest of 'mbr' * untouched. */ void MBR_pcopy(struct disk *disk, struct mbr *mbr) { int i, fd, error; struct dos_mbr dos_mbr; struct dos_partition dos_parts[NDOSPART]; fd = DISK_open(disk->name, O_RDONLY); error = MBR_read(fd, 0, &dos_mbr); close(fd); if (error == -1) return; memcpy(dos_parts, dos_mbr.dmbr_parts, sizeof(dos_parts)); for (i = 0; i < NDOSPART; i++) PRT_parse(disk, &dos_parts[i], 0, 0, &mbr->part[i]); }