ref: b465297573ef0ae41d3a2cdbcb5528f3388ba6d9
dir: /lwext4/ext4_mbr.c/
/* * Copyright (c) 2015 Grzegorz Kostka ([email protected]) * 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_debug.h" #include "ext4_mbr.h" #include <inttypes.h> #include <string.h> #define MBR_SIGNATURE 0xAA55 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; } __attribute__((packed)); struct ext4_mbr { uint8_t bootstrap[446]; struct ext4_part_entry part_entry[4]; uint16_t signature; } __attribute__((packed)); 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; } /** * @} */