/* * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com) * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * - Redistributions of source code must retain the above copyright *   notice, this list of conditions and the following disclaimer. * - 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. * - The name of the author may not be used to endorse or promote products *   derived from this software without specific prior written permission. * * 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. */ /** @addtogroup lwext4 * @{ *//** * @file  ext4_mbr.c * @brief Master boot record parser */ #include <ext4_config.h>#include <ext4_types.h>#include <ext4_misc.h>#include <ext4_errno.h>#include <ext4_debug.h> #include <ext4_mbr.h> #include <inttypes.h>#include <string.h> #define MBR_SIGNATURE 0xAA55 #ifdef __plan9__#pragma pack on#else#pragma pack(push, 1)#endif struct ext4_part_entry {	uint8_t status;	uint8_t chs1[3];	uint8_t type;	uint8_t chs2[3];	uint32_t first_lba;	uint32_t sectors;}; struct ext4_mbr {	uint8_t bootstrap[442];	uint32_t disk_id;	struct ext4_part_entry part_entry[4];	uint16_t signature;}; #ifdef __plan9__#pragma pack off#else#pragma pack(pop)#endif int ext4_mbr_scan(struct ext4_blockdev *parent, struct ext4_mbr_bdevs *bdevs){	int r;	size_t i; 	ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_scan\n");	memset(bdevs, 0, sizeof(struct ext4_mbr_bdevs));	r = ext4_block_init(parent);	if (r != EOK)		return r; 	r = ext4_block_readbytes(parent, 0, parent->bdif->ph_bbuf, 512);	if (r != EOK) {		goto blockdev_fini;	} 	const struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf; 	if (to_le16(mbr->signature) != MBR_SIGNATURE) {		ext4_dbg(DEBUG_MBR, DBG_ERROR "ext4_mbr_scan: unknown "			 "signature: 0x%x\n", to_le16(mbr->signature));		r = ENOENT;		goto blockdev_fini;	} 	/*Show bootstrap code*/	ext4_dbg(DEBUG_MBR, "mbr_part: bootstrap:");	for (i = 0; i < sizeof(mbr->bootstrap); ++i) {		if (!(i & 0xF))				ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "\n");		ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "%02x, ", mbr->bootstrap[i]);	} 	ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "\n\n");	for (i = 0; i < 4; ++i) {		const struct ext4_part_entry *pe = &mbr->part_entry[i];		ext4_dbg(DEBUG_MBR, "mbr_part: %d\n", (int)i);		ext4_dbg(DEBUG_MBR, "\tstatus: 0x%x\n", pe->status);		ext4_dbg(DEBUG_MBR, "\ttype 0x%x:\n", pe->type);		ext4_dbg(DEBUG_MBR, "\tfirst_lba: 0x%"PRIx32"\n", pe->first_lba);		ext4_dbg(DEBUG_MBR, "\tsectors: 0x%"PRIx32"\n", pe->sectors); 		if (!pe->sectors)			continue; /*Empty entry*/ 		if (pe->type != 0x83)			continue; /*Unsupported entry. 0x83 - linux native*/ 		bdevs->partitions[i].bdif = parent->bdif;		bdevs->partitions[i].part_offset =			(uint64_t)pe->first_lba * parent->bdif->ph_bsize;		bdevs->partitions[i].part_size =			(uint64_t)pe->sectors * parent->bdif->ph_bsize;	} 	blockdev_fini:	ext4_block_fini(parent);	return r;} int ext4_mbr_write(struct ext4_blockdev *parent, struct ext4_mbr_parts *parts, uint32_t disk_id){	int r;	uint64_t disk_size;	uint32_t division_sum = parts->division[0] + parts->division[1] +				parts->division[2] + parts->division[3]; 	if (division_sum > 100)		return EINVAL; 	ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_write\n");	r = ext4_block_init(parent);	if (r != EOK)		return r; 	disk_size = parent->part_size; 	/*Calculate CHS*/	uint32_t k = 16;	while ((k < 256) && ((disk_size / parent->bdif->ph_bsize / k / 63) > 1024))		k *= 2; 	if (k == 256)		--k; 	const uint32_t cyl_size = parent->bdif->ph_bsize * 63 * k;	const uint32_t cyl_count = disk_size / cyl_size; 	struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf;	memset(mbr, 0, sizeof(struct ext4_mbr)); 	mbr->disk_id = disk_id; 	uint32_t cyl_it = 0;	for (int i = 0; i < 4; ++i) {		uint32_t cyl_part = cyl_count * parts->division[i] / 100;		if (!cyl_part)			continue; 		uint32_t part_start = cyl_it * cyl_size;		uint32_t part_size = cyl_part * cyl_size; 		if (i == 0) {			part_start += 63;			part_size -= 63 * parent->bdif->ph_bsize;		} 		uint32_t cyl_end = cyl_part + cyl_it - 1; 		mbr->part_entry[i].status = 0;		mbr->part_entry[i].chs1[0] = i ? 0 : 1;;		mbr->part_entry[i].chs1[1] = ((cyl_it >> 2) & 0xC0) + 1;		mbr->part_entry[i].chs1[2] = cyl_it & 0xFF;		mbr->part_entry[i].type = 0x83;		mbr->part_entry[i].chs2[0] = k - 1;		mbr->part_entry[i].chs2[1] = ((cyl_end >> 2) & 0xC0) + 63;		mbr->part_entry[i].chs2[2] = cyl_end & 0xFF; 		mbr->part_entry[i].first_lba = part_start;		mbr->part_entry[i].sectors = part_size / parent->bdif->ph_bsize; 		cyl_it += cyl_part;	} 	mbr->signature = MBR_SIGNATURE;	r = ext4_block_writebytes(parent, 0, parent->bdif->ph_bbuf, 512);	if (r != EOK)		goto blockdev_fini;  	blockdev_fini:	ext4_block_fini(parent);	return r;} /** * @} */