84 lines
2.3 KiB
C
84 lines
2.3 KiB
C
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#include <stdint.h>
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/**
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* media organization:
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* * boot record (1 sector, so could be called boot sector): BPB + Extended Boot Record
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* * File Allocation Table (FAT)
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* * data area
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*/
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struct ebr_fat16 { // Extended Boot Record for FAT16
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uint8_t drive_number;
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uint8_t flags;
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uint8_t signature; // Must be 0x29 for FAT16
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uint8_t vol_id[4];
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uint8_t vol_label[11];
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uint8_t sys_id[8]; // Do not trust this!
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uint8_t bootcode[448];
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uint16_t bootable_signature; // 0xAA55
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} __attribute__((packed));
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struct ebr_fat32 { // Extended Boot Record for FAT32
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uint32_t fat_size;
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uint16_t flags;
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uint16_t fat_version_number;
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uint32_t root_cluster_nb;
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uint8_t reserved[12];
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uint8_t drive_number;
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uint8_t flags_nt;
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uint8_t signature;
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uint8_t vol_id[4];
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uint8_t vol_label[11];
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uint8_t sys_id[8]; // Should be always "FAT32"
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uint8_t bootcode[420];
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uint16_t bootable_signature; // 0xAA55
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} __attribute__((packed));
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struct bpb { // Bios Param Block
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uint8_t jump_ins[3];
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uint8_t oem_id[3];
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uint16_t bytes_per_sector;
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uint8_t sector_per_cluster;
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uint16_t reserved_sectors; // boot sectors included
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uint8_t nb_fat;
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uint16_t nb_root_dirs;
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uint16_t nb_sectors;
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uint8_t media_description_type;
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uint16_t sectors_per_fat;
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uint16_t sectors_per_track;
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uint16_t number_of_heads;
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uint32_t hidden_sectors;
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uint32_t nb_large_sectors;
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union {
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struct ebr_fat32 fat32;
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struct ebr_fat16 fat16;
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};
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} __attribute__((packed));
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typedef enum {
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READ_ONLY = 0x01,
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HIDDEN = 0x02,
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SYSTEM = 0x04,
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VOLUME_ID = 0x08,
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DIRECTORY = 0x10,
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ARCHIVE = 0x20,
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LFN = READ_ONLY | HIDDEN | SYSTEM | VOLUME_ID,
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} __attribute__((__packed__)) directory_entry_type_t;
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struct directory_entry {
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uint8_t filename[11];
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directory_entry_type_t type;
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uint8_t reserved;
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uint8_t creation_time_hundredths_sec;
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uint16_t creation_time; // hour[5] min[6] sec[5]
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uint16_t creation_date; // year[7] month[4] day[5]
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uint16_t last_access_date; // year[7] month[4] day[5]
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uint16_t cluster_nb_high;
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uint16_t modification_time; // hour[5] min[6] sec[5]
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uint16_t modification_date; // year[7] month[4] day[5]
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uint16_t cluster_nb_low;
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uint32_t size; // in bytes
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} __attribute__((packed));
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