Nigel
a77621faf5
- Improved the run bash script to exit when an error occurs in one of the sub tasks - Wrote basic FAT16 functions that should give enough information to properly implement the rest of the driver - FAT structure namings are now in accordence with the microsoft spec of March 2005
154 lines
4.7 KiB
C++
154 lines
4.7 KiB
C++
//
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// Created by nigel on 21/02/23.
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//
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#pragma once
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#include "../../vfs/vfs_types.h"
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#include "../../vfs/vfs_types.h"
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#include "../../partitiontables/mbr/MasterBootRecord.h"
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struct ExtendedBootRecord_FAT16{
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uint8_t DrvNum;
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uint8_t Reserved1;
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uint8_t BootSig;
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const uint32_t VolID;
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uint8_t VolLab [11];
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uint8_t FilSysType [8];
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uint8_t bootCode [448];
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uint16_t Signature_word;
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uint8_t SecRmndr[512];
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}__attribute__((packed));
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struct ExtendedBootRecord_FAT32{
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uint32_t SectorsPerFAT;
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uint16_t Flags;
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const uint16_t FAT_VERSION_NUMBER;
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uint32_t rootDirectory_clusterNumber;// Often set to 2;
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uint16_t FSInfo_SectorNumber;
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uint16_t backup_bpb_sectorNumber;
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uint8_t Reserved [12];
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uint8_t DriveNumber;
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uint8_t Reserved2;
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uint8_t Signature; // must be 0x28 or 0x29
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uint32_t VOLUME_ID_SERIAL;
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uint8_t volume_label[11];
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uint8_t SystemIdentifierString [8]; // ALWAYS "FAT32 " but spec says do not trust
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uint8_t BootCode [420]; // NICE
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uint16_t PartitionSignature; // 0xAA55
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}__attribute__((packed));
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struct BiosParameterBlock {
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uint8_t jmpBoot[3];
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uint8_t OEMName [8];
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uint16_t BytsPerSec ; // I suspect would be 512
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uint8_t SecPerClus ;
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uint16_t RsvdSecCnt;
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uint8_t NumFATs; // Probably equals 2
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uint16_t RootEntCnt; // Root directory must contain entire sectors
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uint16_t TotSec16 ; // 0 means >65535 sectors in volume , actual count can be found in LargeSectorCount
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uint8_t Media ; // Indication the media descriptor type
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uint16_t FATSz16;// only in FAT12 / FAT 16
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uint16_t SecPerTrk;
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uint16_t NumHeads;
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uint32_t HiddSec;
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uint32_t TotSec32;
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ExtendedBootRecord_FAT16 ebpb;
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}__attribute__((packed));
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struct DIR {
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uint8_t Name [11];
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uint8_t ATTR ;
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uint8_t NTRes;
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uint8_t CrtTimeTenth; // File Creation time component - count of tenths of a second (between 0 and 199)
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uint16_t CrtTime; // Creation time. Granularity is 2 seconds
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uint16_t CrtDate; // Creation date.
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uint16_t LstAccDate; // Last Access Date (Last read or write date)
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uint16_t FstClusHi; // High Word of first data cluster for file/directory described
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uint16_t WrtTime; // Last Modification time | Must equal CrtTime
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uint16_t WrtDate; // Last Modification date | Must equal CrtDate
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uint16_t FstClusLO; // Low word of first data cluster for file/directory described
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uint32_t FileSize; // size in bytes of file/directory described
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}__attribute__((packed));
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typedef struct _DIRECTORY{
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uint8_t Filename[8];
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uint8_t Ext[3];
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uint8_t Attrib;
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uint8_t Reserved;
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uint8_t TimeCreatedMs;
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uint16_t TimeCreated;
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uint16_t DateCreated;
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uint16_t DateLastAccessed;
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uint16_t FirstClusterHiBytes;
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uint16_t LastModTime;
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uint16_t LastModDate;
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uint16_t FirstCluster;
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uint32_t FileSize;
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}__attribute__((packed)) DIRECTORY, *PDIRECTORY;
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enum struct FAT_TYPE{
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FAT12,
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FAT16,
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FAT32,
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VFAT,
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UNKOWN
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};
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class FAT {
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public:
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// Wanted API for vfs
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static file Open(char* filename);
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static int close(file* file);
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static int Read(file* file, void* buffer , int length);
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static int Write(file* file, const void* buffer, int length);
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static int create(inode* dir_node, inode** target, const char* component_name);
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static int lookup(inode* , inode**, const char*);
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static int compare(directoryEntry* , char* , char*);
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static superblock* Mount(filesystem* fs, const char* name ,vfsmount* mount);
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// TEMP
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static void listFilesInRoot(MBR* mbr, BiosParameterBlock* bpb );
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static BiosParameterBlock* getBPB( bool DEBUG =false );
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static FAT_TYPE determineFATType(BiosParameterBlock* bpb);
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static uint16_t GetFATEntry(BiosParameterBlock*, unsigned int);
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static uint16_t DetermineFreeSpace();
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static int GetSectorOfRootDirectory(BiosParameterBlock*);
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static int RootDirSize(BiosParameterBlock*);
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static const int FREE = 0x0000;
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static const int ALLOCATED = 0x0002;
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static const int BAD = 0xFFF7;
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static const int EOF = 0xFFFF;
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static const int ClnShutBitMask = 0x8000;
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static const int HrdErrBitMask = 0x4000;
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static const char DOS_TRAILING_SPACE = 0x20;
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static const char FREE_DIR = 0xE5; // If KANJI charset 0x05
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static const char FREE_DIR_2 = 0x00; // All directories after this are free including this one
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enum ATTRIBUTES {
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ATTR_READ_ONLY = 0x01,
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ATTR_HIDDEN = 0x02,
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ATTR_SYSTEM = 0x04,
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ATTR_VOLUME_ID = 0x08,
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ATTR_DIRECTORY = 0x10,
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ATTR_ARCHIVE = 0x20,
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ATTR_LONG_NAME = (ATTR_READ_ONLY | ATTR_HIDDEN | ATTR_SYSTEM | ATTR_VOLUME_ID)
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};
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private:
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enum ENTRY_SIZE {
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FAT12 = 12,
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FAT16 = 16,
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FAT32 = 32
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};
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};
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