1 | /* |
2 | * Copyright (c) 2015 Grzegorz Kostka (kostka.grzegorz@gmail.com) |
3 | * All rights reserved. |
4 | * |
5 | * Redistribution and use in source and binary forms, with or without |
6 | * modification, are permitted provided that the following conditions |
7 | * are met: |
8 | * |
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. |
16 | * |
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. |
27 | */ |
28 | |
29 | /** @addtogroup lwext4 |
30 | * @{ |
31 | */ |
32 | /** |
33 | * @file ext4_mbr.c |
34 | * @brief Master boot record parser |
35 | */ |
36 | |
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> |
42 | |
43 | #include <ext4_mbr.h> |
44 | |
45 | #include <inttypes.h> |
46 | #include <string.h> |
47 | |
48 | #define MBR_SIGNATURE 0xAA55 |
49 | |
50 | #pragma pack(push, 1) |
51 | |
52 | struct ext4_part_entry { |
53 | uint8_t status; |
54 | uint8_t chs1[3]; |
55 | uint8_t type; |
56 | uint8_t chs2[3]; |
57 | uint32_t first_lba; |
58 | uint32_t sectors; |
59 | }; |
60 | |
61 | struct ext4_mbr { |
62 | uint8_t bootstrap[442]; |
63 | uint32_t disk_id; |
64 | struct ext4_part_entry part_entry[4]; |
65 | uint16_t signature; |
66 | }; |
67 | |
68 | #pragma pack(pop) |
69 | |
70 | int ext4_mbr_scan(struct ext4_blockdev *parent, struct ext4_mbr_bdevs *bdevs) |
71 | { |
72 | int r; |
73 | size_t i; |
74 | |
75 | ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_scan\n" ); |
76 | memset(dest: bdevs, c: 0, size: sizeof(struct ext4_mbr_bdevs)); |
77 | r = ext4_block_init(bdev: parent); |
78 | if (r != EOK) |
79 | return r; |
80 | |
81 | r = ext4_block_readbytes(bdev: parent, off: 0, buf: parent->bdif->ph_bbuf, len: 512); |
82 | if (r != EOK) { |
83 | goto blockdev_fini; |
84 | } |
85 | |
86 | const struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf; |
87 | |
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)); |
91 | r = ENOENT; |
92 | goto blockdev_fini; |
93 | } |
94 | |
95 | /*Show bootstrap code*/ |
96 | ext4_dbg(DEBUG_MBR, "mbr_part: bootstrap:" ); |
97 | for (i = 0; i < sizeof(mbr->bootstrap); ++i) { |
98 | if (!(i & 0xF)) |
99 | ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "\n" ); |
100 | ext4_dbg(DEBUG_MBR | DEBUG_NOPREFIX, "%02x, " , mbr->bootstrap[i]); |
101 | } |
102 | |
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); |
111 | |
112 | if (!pe->sectors) |
113 | continue; /*Empty entry*/ |
114 | |
115 | if (pe->type != 0x83) |
116 | continue; /*Unsupported entry. 0x83 - linux native*/ |
117 | |
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; |
123 | } |
124 | |
125 | blockdev_fini: |
126 | ext4_block_fini(bdev: parent); |
127 | return r; |
128 | } |
129 | |
130 | int ext4_mbr_write(struct ext4_blockdev *parent, struct ext4_mbr_parts *parts, uint32_t disk_id) |
131 | { |
132 | int r; |
133 | uint64_t disk_size; |
134 | uint32_t division_sum = parts->division[0] + parts->division[1] + |
135 | parts->division[2] + parts->division[3]; |
136 | |
137 | if (division_sum > 100) |
138 | return EINVAL; |
139 | |
140 | ext4_dbg(DEBUG_MBR, DBG_INFO "ext4_mbr_write\n" ); |
141 | r = ext4_block_init(bdev: parent); |
142 | if (r != EOK) |
143 | return r; |
144 | |
145 | disk_size = parent->part_size; |
146 | |
147 | /*Calculate CHS*/ |
148 | uint32_t k = 16; |
149 | while ((k < 256) && ((disk_size / k / 63) > 1024)) |
150 | k *= 2; |
151 | |
152 | if (k == 256) |
153 | --k; |
154 | |
155 | const uint32_t cyl_size = 63 * k; |
156 | const uint32_t cyl_count = disk_size / cyl_size; |
157 | |
158 | struct ext4_mbr *mbr = (void *)parent->bdif->ph_bbuf; |
159 | memset(dest: mbr, c: 0, size: sizeof(struct ext4_mbr)); |
160 | |
161 | mbr->disk_id = disk_id; |
162 | |
163 | uint32_t cyl_it = 0; |
164 | for (int i = 0; i < 4; ++i) { |
165 | uint32_t cyl_part = cyl_count * parts->division[i] / 100; |
166 | if (!cyl_part) |
167 | continue; |
168 | |
169 | uint32_t part_start = cyl_it * cyl_size; |
170 | uint32_t part_size = cyl_part * cyl_size; |
171 | |
172 | if (i == 0) { |
173 | part_start += 63; |
174 | part_size -= 63 * parent->bdif->ph_bsize; |
175 | } |
176 | |
177 | uint32_t cyl_end = cyl_part + cyl_it - 1; |
178 | |
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; |
187 | |
188 | mbr->part_entry[i].first_lba = part_start; |
189 | mbr->part_entry[i].sectors = part_size / parent->bdif->ph_bsize; |
190 | |
191 | cyl_it += cyl_part; |
192 | } |
193 | |
194 | mbr->signature = MBR_SIGNATURE; |
195 | r = ext4_block_writebytes(bdev: parent, off: 0, buf: parent->bdif->ph_bbuf, len: 512); |
196 | if (r != EOK) |
197 | goto blockdev_fini; |
198 | |
199 | |
200 | blockdev_fini: |
201 | ext4_block_fini(bdev: parent); |
202 | return r; |
203 | } |
204 | |
205 | /** |
206 | * @} |
207 | */ |
208 | |
209 | |