2 * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com)
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
9 * - Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * - Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * - The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission.
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29 /** @addtogroup lwext4
34 * @brief Master boot record parser
37 #include <ext4_config.h>
38 #include <ext4_types.h>
39 #include <ext4_misc.h>
40 #include <ext4_errno.h>
41 #include <ext4_debug.h>
48 #define MBR_SIGNATURE 0xAA55
52 struct ext4_part_entry {
62 uint8_t bootstrap[442];
64 struct ext4_part_entry part_entry[4];
70 int ext4_mbr_scan(struct ext4_blockdev *parent, struct ext4_mbr_bdevs *bdevs)
75 ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_scan\n");
76 memset(bdevs, 0, sizeof(struct ext4_mbr_bdevs));
77 r = ext4_block_init(parent);
81 r = ext4_block_readbytes(parent, 0, parent->bdif->ph_bbuf, 512);
86 const struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf;
88 if (to_le16(mbr->signature) != MBR_SIGNATURE) {
89 ext4_dbg(DEBUG_MBR, DBG_ERROR "ext4_mbr_scan: unknown "
90 "signature: 0x%x\n", to_le16(mbr->signature));
95 /*Show bootstrap code*/
96 ext4_dbg(DEBUG_MBR, "mbr_part: bootstrap:");
97 for (i = 0; i < sizeof(mbr->bootstrap); ++i) {
99 ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "\n");
100 ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "%02x, ", mbr->bootstrap[i]);
103 ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "\n\n");
104 for (i = 0; i < 4; ++i) {
105 const struct ext4_part_entry *pe = &mbr->part_entry[i];
106 ext4_dbg(DEBUG_MBR, "mbr_part: %d\n", (int)i);
107 ext4_dbg(DEBUG_MBR, "\tstatus: 0x%x\n", pe->status);
108 ext4_dbg(DEBUG_MBR, "\ttype 0x%x:\n", pe->type);
109 ext4_dbg(DEBUG_MBR, "\tfirst_lba: 0x%"PRIx32"\n", pe->first_lba);
110 ext4_dbg(DEBUG_MBR, "\tsectors: 0x%"PRIx32"\n", pe->sectors);
113 continue; /*Empty entry*/
115 if (pe->type != 0x83)
116 continue; /*Unsupported entry. 0x83 - linux native*/
118 bdevs->partitions[i].bdif = parent->bdif;
119 bdevs->partitions[i].part_offset =
120 (uint64_t)pe->first_lba * parent->bdif->ph_bsize;
121 bdevs->partitions[i].part_size =
122 (uint64_t)pe->sectors * parent->bdif->ph_bsize;
126 ext4_block_fini(parent);
130 int ext4_mbr_write(struct ext4_blockdev *parent, struct ext4_mbr_parts *parts, uint32_t disk_id)
134 uint32_t division_sum = parts->division[0] + parts->division[1] +
135 parts->division[2] + parts->division[3];
137 if (division_sum > 100)
140 ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_write\n");
141 r = ext4_block_init(parent);
145 disk_size = parent->part_size;
149 while ((k < 256) && ((disk_size / k / 63) > 1024))
155 const uint32_t cyl_size = 63 * k;
156 const uint32_t cyl_count = disk_size / cyl_size;
158 struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf;
159 memset(mbr, 0, sizeof(struct ext4_mbr));
161 mbr->disk_id = disk_id;
164 for (int i = 0; i < 4; ++i) {
165 uint32_t cyl_part = cyl_count * parts->division[i] / 100;
169 uint32_t part_start = cyl_it * cyl_size;
170 uint32_t part_size = cyl_part * cyl_size;
174 part_size -= 63 * parent->bdif->ph_bsize;
177 uint32_t cyl_end = cyl_part + cyl_it - 1;
179 mbr->part_entry[i].status = 0;
180 mbr->part_entry[i].chs1[0] = i ? 0 : 1;;
181 mbr->part_entry[i].chs1[1] = (cyl_it >> 2) + 1;
182 mbr->part_entry[i].chs1[2] = cyl_it;
183 mbr->part_entry[i].type = 0x83;
184 mbr->part_entry[i].chs2[0] = k - 1;
185 mbr->part_entry[i].chs2[1] = (cyl_end >> 2) + 63;
186 mbr->part_entry[i].chs2[2] = cyl_end;
188 mbr->part_entry[i].first_lba = part_start;
189 mbr->part_entry[i].sectors = part_size / parent->bdif->ph_bsize;
194 mbr->signature = MBR_SIGNATURE;
195 r = ext4_block_writebytes(parent, 0, parent->bdif->ph_bbuf, 512);
201 ext4_block_fini(parent);