filesys.h

linux文件系统试验 一、实验目的 学习有关linux文件管理程序如何组织的知识

#ifndef FILESYS_H
#define FILESYS_H

#define DEVNAME "/dev/fd0H1440"

#define DIR_ENTRY_SIZE 32
#define SECTOR_SIZE    512
#define FAT_ONE_OFFSET 0x200
#define FAT_TWO_OFFSET 0x1400
#define ROOTDIR_OFFSET 0x2600
#define DATA_OFFSET    0x4200

/* mask for the entry attribute */
#define ATTR_READONLY 0x01
#define ATTR_HIDDEN   0x02
#define ATTR_SYSTEM   0x04
#define ATTR_VLABEL   0x08
#define ATTR_SUBDIR   0x10
#define ATTR_ARCHIVE  0x20

/* mask for time 5:6:5*/
#define MASK_HOUR     0xf800
#define MASK_MIN      0x07e0
#define MASK_SEC      0x001f

/* mask for date 7:4:5*/
#define MASK_YEAR     0xfe00
#define MASK_MONTH    0x01e0
#define MASK_DAY      0x001f

struct BootDescriptor_t {
  unsigned char Oem_name[9];     /* 0x03 - 0x0a */
  int BytesPerSector;            /* 0x0b - 0x0c */
  int SectorsPerCluster;         /* 0x0d        */
  int ReservedSectors;           /* 0x0e - 0x0f */
  int FATs;                      /* 0x10        */
  int RootDirEntries;            /* 0x11 - 0x12 */
  int LogicSectors;              /* 0x13 - 0x14 */
  int MediaType;                 /* 0x15        */
  int SectorsPerFAT;             /* 0x16 - 0x17 */
  int SectorsPerTrack;           /* 0x18 - 0x19 */
  int Heads;                     /* 0x1a - 0x1b */
  int HiddenSectors;             /* 0x1c - 0x1d */
};

struct Entry {
  unsigned char short_name[12];  /* Bytes 0  - 10, 11 Bytes name */
  unsigned char long_name[27];   /* not used       26 Bytes name */
  unsigned short hour,min,sec;   /* Bytes 22 - 23 */
  unsigned short year,month,day; /* Bytes 24 - 25 */
  unsigned short FirstCluster;   /* Bytes 26 - 27 */
  unsigned int size;            /* Bytes 28 - 31 */
  /* attribute                      Bytes 11    
   * 7  6  5  4  3  2  1  0 
   * N  N  A  D  V  S  H  R         N: not used
   */
  unsigned char readonly:1;      /* R */
  unsigned char hidden:1;        /* H */
  unsigned char system:1;        /* S */
  unsigned char vlabel:1;        /* V */
  unsigned char subdir:1;        /* D */
  unsigned char archive:1;       /* A */
};

int fd_load();
int fd_ls();
int fd_cd(char *dir);
int fd_rm(char *file_name);

void findDate(unsigned short *year,
	      unsigned short *month,
	      unsigned short *day,
	      unsigned char info[2]);

void findTime(unsigned short *hour,
	      unsigned short *min,
	      unsigned short *sec,
	      unsigned char info[2]);

int  ReadFat();
int  WriteFat();
void ScanBootSector();
void ScanRootEntry();
int  ScanEntry(char *entryname,struct Entry *pentry,int mode);
int  GetEntry(struct Entry *entry);
void FileNameFormat(unsigned char *name);
unsigned short GetFatCluster(unsigned short prev);
void ClearFatCluster(unsigned short cluster);
#endif