1 |
|
|
/*************************************************************************** |
2 |
|
|
* Copyright (c) 2024 Microsoft Corporation |
3 |
|
|
* |
4 |
|
|
* This program and the accompanying materials are made available under the |
5 |
|
|
* terms of the MIT License which is available at |
6 |
|
|
* https://opensource.org/licenses/MIT. |
7 |
|
|
* |
8 |
|
|
* SPDX-License-Identifier: MIT |
9 |
|
|
**************************************************************************/ |
10 |
|
|
|
11 |
|
|
|
12 |
|
|
/**************************************************************************/ |
13 |
|
|
/**************************************************************************/ |
14 |
|
|
/** */ |
15 |
|
|
/** FileX Component */ |
16 |
|
|
/** */ |
17 |
|
|
/** Media */ |
18 |
|
|
/** */ |
19 |
|
|
/**************************************************************************/ |
20 |
|
|
/**************************************************************************/ |
21 |
|
|
|
22 |
|
|
#define FX_SOURCE_CODE |
23 |
|
|
|
24 |
|
|
|
25 |
|
|
/* Include necessary system files. */ |
26 |
|
|
|
27 |
|
|
#include "fx_api.h" |
28 |
|
|
#include "fx_system.h" |
29 |
|
|
#include "fx_media.h" |
30 |
|
|
#include "fx_utility.h" |
31 |
|
|
|
32 |
|
|
|
33 |
|
|
/**************************************************************************/ |
34 |
|
|
/* */ |
35 |
|
|
/* FUNCTION RELEASE */ |
36 |
|
|
/* */ |
37 |
|
|
/* _fx_media_boot_info_extract PORTABLE C */ |
38 |
|
|
/* 6.1.10 */ |
39 |
|
|
/* AUTHOR */ |
40 |
|
|
/* */ |
41 |
|
|
/* William E. Lamie, Microsoft Corporation */ |
42 |
|
|
/* */ |
43 |
|
|
/* DESCRIPTION */ |
44 |
|
|
/* */ |
45 |
|
|
/* This function extracts and validates the information from the boot */ |
46 |
|
|
/* record found in the memory buffer. If the boot record is invalid, */ |
47 |
|
|
/* an FX_MEDIA_INVALID status is returned to the caller. */ |
48 |
|
|
/* */ |
49 |
|
|
/* The FAT boot sector (512 bytes) that is operated on by this */ |
50 |
|
|
/* function must look like the following: */ |
51 |
|
|
/* */ |
52 |
|
|
/* Byte Offset Meaning Size */ |
53 |
|
|
/* */ |
54 |
|
|
/* 0x000 Jump Instructions 3 */ |
55 |
|
|
/* 0x003 OEM Name 8 */ |
56 |
|
|
/* 0x00B *Bytes per Sector 2 */ |
57 |
|
|
/* 0x00D *Sectors per Cluster 1 */ |
58 |
|
|
/* 0x00E *Reserved Sectors 2 */ |
59 |
|
|
/* 0x010 *Number of FATs 1 */ |
60 |
|
|
/* 0x011 *Max Root Dir Entries 2 */ |
61 |
|
|
/* 0x013 *Number of Sectors 2 */ |
62 |
|
|
/* 0x015 Media Type 1 */ |
63 |
|
|
/* 0x016 *Sectors per FAT 2 */ |
64 |
|
|
/* 0x018 *Sectors per Track 2 */ |
65 |
|
|
/* 0x01A *Number of Heads 2 */ |
66 |
|
|
/* 0x01C *Hidden Sectors 4 */ |
67 |
|
|
/* 0x020 *Huge Sectors 4 */ |
68 |
|
|
/* 0x024 Drive Number 1 */ |
69 |
|
|
/* 0x025 Reserved 1 */ |
70 |
|
|
/* 0x026 Boot Signature 1 */ |
71 |
|
|
/* 0x027 Volume ID 4 */ |
72 |
|
|
/* 0x02B Volume Label 11 */ |
73 |
|
|
/* 0x036 File System Type 8 */ |
74 |
|
|
/* ... ... ... */ |
75 |
|
|
/* 0x1FE **Signature (0x55aa) 2 */ |
76 |
|
|
/* */ |
77 |
|
|
/* * Denotes which elements of the boot record */ |
78 |
|
|
/* FileX uses. */ |
79 |
|
|
/* */ |
80 |
|
|
/* **Denotes the element is checked by the I/O */ |
81 |
|
|
/* driver. This eliminates the need for a minimum */ |
82 |
|
|
/* 512-byte buffer for FileX. */ |
83 |
|
|
/* */ |
84 |
|
|
/* Note: All values above are in little endian format, i.e. the LSB is */ |
85 |
|
|
/* in the lowest address. */ |
86 |
|
|
/* */ |
87 |
|
|
/* INPUT */ |
88 |
|
|
/* */ |
89 |
|
|
/* media_ptr Media control block pointer */ |
90 |
|
|
/* */ |
91 |
|
|
/* OUTPUT */ |
92 |
|
|
/* */ |
93 |
|
|
/* return status */ |
94 |
|
|
/* */ |
95 |
|
|
/* CALLS */ |
96 |
|
|
/* */ |
97 |
|
|
/* _fx_utility_16_unsigned_read Read a UINT from buffer */ |
98 |
|
|
/* _fx_utility_32_unsigned_read Read a ULONG from buffer */ |
99 |
|
|
/* _fx_utility_64_unsigned_read Read a ULONG64 from memory */ |
100 |
|
|
/* */ |
101 |
|
|
/* CALLED BY */ |
102 |
|
|
/* */ |
103 |
|
|
/* _fx_media_open Media open function */ |
104 |
|
|
/* */ |
105 |
|
|
/* RELEASE HISTORY */ |
106 |
|
|
/* */ |
107 |
|
|
/* DATE NAME DESCRIPTION */ |
108 |
|
|
/* */ |
109 |
|
|
/* 05-19-2020 William E. Lamie Initial Version 6.0 */ |
110 |
|
|
/* 09-30-2020 William E. Lamie Modified comment(s), */ |
111 |
|
|
/* resulting in version 6.1 */ |
112 |
|
|
/* 01-31-2022 Bhupendra Naphade Modified comment(s), added */ |
113 |
|
|
/* check for bimap cache size, */ |
114 |
|
|
/* resulting in version 6.1.10 */ |
115 |
|
|
/* */ |
116 |
|
|
/**************************************************************************/ |
117 |
|
6028 |
UINT _fx_media_boot_info_extract(FX_MEDIA *media_ptr) |
118 |
|
|
{ |
119 |
|
|
|
120 |
|
|
UCHAR *boot_sector; |
121 |
|
|
|
122 |
|
|
|
123 |
|
|
/* Move the buffer pointer into a local copy. */ |
124 |
|
6028 |
boot_sector = media_ptr -> fx_media_driver_buffer; |
125 |
|
|
|
126 |
|
|
/* Extract the number of bytes per sector. */ |
127 |
|
6028 |
media_ptr -> fx_media_bytes_per_sector = _fx_utility_16_unsigned_read(&boot_sector[FX_BYTES_SECTOR]); |
128 |
✓✓ |
6028 |
if (media_ptr -> fx_media_bytes_per_sector == 0) |
129 |
|
1 |
return(FX_MEDIA_INVALID); |
130 |
|
|
|
131 |
|
|
|
132 |
|
|
/* FAT12/16/32 volume. */ |
133 |
|
|
/* Extract the number of sectors per track. */ |
134 |
|
6027 |
media_ptr -> fx_media_sectors_per_track = _fx_utility_16_unsigned_read(&boot_sector[FX_SECTORS_PER_TRK]); |
135 |
|
|
|
136 |
|
|
/* Extract the number of heads. */ |
137 |
|
6027 |
media_ptr -> fx_media_heads = _fx_utility_16_unsigned_read(&boot_sector[FX_HEADS]); |
138 |
|
|
|
139 |
|
|
/* Extract the total number of sectors. */ |
140 |
|
6027 |
media_ptr -> fx_media_total_sectors = _fx_utility_16_unsigned_read(&boot_sector[FX_SECTORS]); |
141 |
✓✓ |
6027 |
if (media_ptr -> fx_media_total_sectors == 0) |
142 |
|
|
{ |
143 |
|
3834 |
media_ptr -> fx_media_total_sectors = _fx_utility_32_unsigned_read(&boot_sector[FX_HUGE_SECTORS]); |
144 |
|
|
} |
145 |
|
|
|
146 |
✓✓ |
6027 |
if (media_ptr -> fx_media_total_sectors == 0) |
147 |
|
|
{ |
148 |
|
1 |
return(FX_MEDIA_INVALID); |
149 |
|
|
} |
150 |
|
|
|
151 |
|
|
/* Extract the number of reserved sectors before the first FAT. */ |
152 |
|
6026 |
media_ptr -> fx_media_reserved_sectors = _fx_utility_16_unsigned_read(&boot_sector[FX_RESERVED_SECTORS]); |
153 |
✓✓ |
6026 |
if (media_ptr -> fx_media_reserved_sectors == 0) |
154 |
|
|
{ |
155 |
|
1 |
return(FX_MEDIA_INVALID); |
156 |
|
|
} |
157 |
|
|
|
158 |
|
|
/* Extract the number of sectors per cluster. */ |
159 |
|
6025 |
media_ptr -> fx_media_sectors_per_cluster = ((UINT)boot_sector[FX_SECTORS_CLUSTER] & 0xFF); |
160 |
|
|
|
161 |
|
|
/* There should always be at least one reserved sector, representing the boot record itself. */ |
162 |
✓✓ |
6025 |
if (media_ptr -> fx_media_sectors_per_cluster == 0) |
163 |
|
|
{ |
164 |
|
1 |
return(FX_MEDIA_INVALID); |
165 |
|
|
} |
166 |
|
|
|
167 |
|
|
/* Extract the number of sectors per FAT. */ |
168 |
|
6024 |
media_ptr -> fx_media_sectors_per_FAT = _fx_utility_16_unsigned_read(&boot_sector[FX_SECTORS_PER_FAT]); |
169 |
✓✓ |
6024 |
if (media_ptr -> fx_media_sectors_per_FAT == 0) |
170 |
|
|
{ |
171 |
|
3833 |
media_ptr -> fx_media_sectors_per_FAT = _fx_utility_32_unsigned_read(&boot_sector[FX_SECTORS_PER_FAT_32]); |
172 |
|
|
} |
173 |
|
|
|
174 |
✓✓ |
6024 |
if (media_ptr -> fx_media_sectors_per_FAT == 0) |
175 |
|
|
{ |
176 |
|
1 |
return(FX_MEDIA_INVALID); |
177 |
|
|
} |
178 |
|
|
|
179 |
|
|
/* Extract the number of FATs. */ |
180 |
|
6023 |
media_ptr -> fx_media_number_of_FATs = ((UINT)boot_sector[FX_NUMBER_OF_FATS] & 0xFF); |
181 |
✓✓ |
6023 |
if (media_ptr -> fx_media_number_of_FATs == 0) |
182 |
|
|
{ |
183 |
|
1 |
return(FX_BOOT_ERROR); |
184 |
|
|
} |
185 |
|
|
|
186 |
|
|
/* Extract the number of hidden sectors. */ |
187 |
|
|
#ifdef FX_DRIVER_USE_64BIT_LBA |
188 |
|
|
media_ptr -> fx_media_hidden_sectors = _fx_utility_64_unsigned_read(&boot_sector[FX_HIDDEN_SECTORS]); |
189 |
|
|
#else |
190 |
|
6022 |
media_ptr -> fx_media_hidden_sectors = _fx_utility_32_unsigned_read(&boot_sector[FX_HIDDEN_SECTORS]); |
191 |
|
|
#endif |
192 |
|
|
/* Extract the number of root directory entries. */ |
193 |
|
6022 |
media_ptr -> fx_media_root_directory_entries = _fx_utility_16_unsigned_read(&boot_sector[FX_ROOT_DIR_ENTRIES]); |
194 |
|
|
|
195 |
|
|
/* Extract root directory starting cluster (32 bit only) and compute start sector */ |
196 |
|
6022 |
media_ptr -> fx_media_root_cluster_32 = _fx_utility_32_unsigned_read(&boot_sector[FX_ROOT_CLUSTER_32]); |
197 |
|
|
|
198 |
|
|
|
199 |
|
|
/* Return a successful status. */ |
200 |
|
6022 |
return(FX_SUCCESS); |
201 |
|
|
} |
202 |
|
|
|