[File System] FAT에 대한 예제코드

2008. 10. 3. 17:36

[File System] FAT에 대한 예제코드

2008. 10. 3. 17:36 in 프로그래밍 세계/OS

3장 실습 소스 < FAT_exam1.c >
#include <stdio.h> #include <windows.h> #include <stdlib.h> #define U8 unsigned char #define S8 char #define U16 unsigned short #define U32 unsigned int #define U64 unsigned __int64 #pragma pack(1) typedef struct _FAT16_BPB_struct{ U8 JmpBoot[3]; U8 OEMName[8]; U16 BytsPerSec; U8 SecPerClus; U16 RsvdSecCnt; U8 NumFATs; U16 RootEntCnt; U16 TotSec16; U8 Media; U16 FATs16; U16 SecPerTrk; U16 NumHeads; U32 HiddSec; U32 TotSec32; //-----공통영역------ U8 DriveNumber; U8 Reserved1; U8 BootSignal; U32 VolumeID; U8 VolumeLabel[11]; U8 FilSysType[8]; //------FAT16영역 U8 BootCodeArea[448]; U16 Signature; }FAT16_BPB; #pragma pack() typedef struct _VOL_struct{ U32 Drive; U32 VolBeginSec; U32 FirstDataSec; U32 RootDirSec; U32 RootEntCnt; U32 RootDirSecCnt; U32 FATSize; U32 FATStartSec; U32 TotalClusCnt; U32 TotalSec; U32 DataSecSize; U32 ClusterSize; U32 SecPerClus; }VolStruct; U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf); U32 get_BPB_info(FAT16_BPB* BPB, VolStruct* pVol); VolStruct gVol; int main(void) { char buf[512]; gVol.Drive = 0x4; gVol.VolBeginSec = 0x00; // memset( buf, 0, 512 ); // HDD_write( gVol.Drive, gVol.VolBeginSec, 1, (unsigned char )buf); if( HDD_read(gVol.Drive, gVol.VolBeginSec, 1 ,(unsigned char )buf ) == 0 ) { printf("Boot Sector Read Failed \n"); return 1; } if( get_BPB_info((FAT16_BPB)buf, &gVol) == 0 ) { printf("It is not FAT16 file System \n"); return 1; } printf(" ------------- volume infomation -------------- \n\n"); printf(" Total Sector = %d sectors \n", gVol.TotalSec); printf(" FAT size = %d sectors \n", gVol.FATSize); printf(" Root Dir Sector = %d \n", gVol.RootDirSec); printf(" Root Dor Sector Count = %d \n", gVol.RootDirSecCnt); printf(" First Data Sector = %d \n", gVol.FirstDataSec); printf(" Data Sector Count = %d Sectors \n", gVol.DataSecSize); printf(" Total Cluster = %d \n", gVol.TotalClusCnt); printf(" Size of Cluster = %d \n", gVol.ClusterSize); system("pause"); return 0; } U32 get_BPB_info(FAT16_BPB BPB, VolStruct* pVol) { if(BPB->RootEntCnt == 0 \|\| BPB->Signature != 0xAA55) { return 0; } //Get Total Sector if( BPB->TotSec16 != 0 ) { pVol->TotalSec = BPB->TotSec16; } else { pVol->TotalSec = BPB->TotSec32; } //Get FAT Size pVol->FATSize = BPB->FATs16; //Get FAT Start Sector pVol->FATStartSec = pVol->VolBeginSec + BPB->RsvdSecCnt; //Get Root Dir Entry Count pVol->RootEntCnt = BPB->RootEntCnt; //Get Root Dir Sector pVol->RootDirSec = pVol->VolBeginSec + BPB->RsvdSecCnt + (BPB->NumFATs * BPB->FATs16); //Get Root Dir Sector Count pVol->RootDirSecCnt = (( BPB->RootEntCnt * 32) + (BPB->BytsPerSec - 1)) / BPB->BytsPerSec; //Get Data Start Sector pVol->FirstDataSec = pVol->VolBeginSec + BPB->RsvdSecCnt +( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt; //Get Size of Data Area pVol->DataSecSize = pVol->TotalSec - ( BPB->RsvdSecCnt + ( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt ); //Get Total Cluster Count pVol->TotalClusCnt = pVol->DataSecSize / BPB->SecPerClus; //Get Size of Cluster pVol->ClusterSize = BPB->SecPerClus * BPB->BytsPerSec; //Get Sector Per Cluster pVol->SecPerClus = BPB->SecPerClus; return 1; } U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf) { U32 ret = 0; U32 ldistanceLow, ldistanceHigh, dwpointer, bytestoread, numread; char cur_drv[100]; HANDLE g_hDevice; sprintf(cur_drv, "\\\\.\\PhysicalDrive%d",(U32)drv); g_hDevice = CreateFile(cur_drv, GENERIC_READ, FILE_SHARE_READ \| FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); if(g_hDevice == INVALID_HANDLE_VALUE) return 0; ldistanceLow = SecAddr << 9; ldistanceHigh = SecAddr >> (32 - 9); dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long )&ldistanceHigh, FILE_BEGIN); if(dwpointer != 0xFFFFFFFF) { bytestoread = blocks 512; ret = ReadFile(g_hDevice, buf, bytestoread, (unsigned long*)&numread, NULL); if(ret) ret = 1; else ret = 0; } CloseHandle(g_hDevice); return ret; }

3장 실습 소스 < FAT_exam1.c >

#include <stdio.h>
#include <windows.h>
#include <stdlib.h>

#define U8 unsigned char
#define S8 char
#define U16 unsigned short
#define U32 unsigned int
#define U64 unsigned __int64

#pragma pack(1)
typedef struct _FAT16_BPB_struct{
U8  JmpBoot[3];
U8  OEMName[8];
U16  BytsPerSec;
U8  SecPerClus;
U16  RsvdSecCnt;
U8  NumFATs;
U16  RootEntCnt;
U16  TotSec16;
U8  Media;
U16  FATs16;
U16  SecPerTrk;
U16  NumHeads;
U32  HiddSec;
U32  TotSec32;
//-----공통영역------
U8  DriveNumber;
U8  Reserved1;
U8  BootSignal;
U32  VolumeID;
U8  VolumeLabel[11];
U8  FilSysType[8];
//------FAT16영역

U8 BootCodeArea[448];
U16 Signature;
}FAT16_BPB;

#pragma pack()

typedef struct _VOL_struct{
U32  Drive;
U32  VolBeginSec;
U32  FirstDataSec;
U32  RootDirSec;
U32  RootEntCnt;
U32  RootDirSecCnt;
U32  FATSize;
U32  FATStartSec;
U32  TotalClusCnt;
U32  TotalSec;
U32  DataSecSize;
U32  ClusterSize;
U32  SecPerClus;
}VolStruct;

U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf);
U32 get_BPB_info(FAT16_BPB* BPB, VolStruct* pVol);

VolStruct gVol;

int main(void)
{

char buf[512];

gVol.Drive = 0x4;
gVol.VolBeginSec = 0x00;
// memset( buf, 0, 512 );

// HDD_write( gVol.Drive, gVol.VolBeginSec, 1, (unsigned char *)buf);

if( HDD_read(gVol.Drive, gVol.VolBeginSec, 1 ,(unsigned char *)buf ) == 0 )
{
printf("Boot Sector Read Failed \n");
return 1;
}

if( get_BPB_info((FAT16_BPB*)buf, &gVol) == 0 )
{
printf("It is not FAT16 file System \n");
return 1;
}

printf(" ------------- volume infomation -------------- \n\n");

printf(" Total Sector             = %d sectors \n", gVol.TotalSec);
printf(" FAT size                 = %d sectors \n", gVol.FATSize);
printf(" Root Dir Sector          = %d         \n", gVol.RootDirSec);
printf(" Root Dor Sector Count    = %d         \n", gVol.RootDirSecCnt);
printf(" First Data Sector        = %d         \n", gVol.FirstDataSec);
printf(" Data Sector Count        = %d Sectors \n", gVol.DataSecSize);
printf(" Total Cluster            = %d         \n", gVol.TotalClusCnt);
printf(" Size of Cluster          = %d         \n", gVol.ClusterSize);
system("pause");
return 0;
}

U32 get_BPB_info(FAT16_BPB* BPB, VolStruct* pVol)
{
if(BPB->RootEntCnt == 0 || BPB->Signature != 0xAA55)
{
return 0;
}

//Get Total Sector
if( BPB->TotSec16 != 0 )
{
pVol->TotalSec = BPB->TotSec16;
}
else
{
pVol->TotalSec = BPB->TotSec32;
}

//Get FAT Size
pVol->FATSize = BPB->FATs16;

//Get FAT Start Sector
pVol->FATStartSec = pVol->VolBeginSec + BPB->RsvdSecCnt;

//Get Root Dir Entry Count
pVol->RootEntCnt = BPB->RootEntCnt;

//Get Root Dir Sector
pVol->RootDirSec = pVol->VolBeginSec + BPB->RsvdSecCnt + (BPB->NumFATs * BPB->FATs16);

//Get Root Dir Sector Count
pVol->RootDirSecCnt = (( BPB->RootEntCnt * 32) + (BPB->BytsPerSec - 1)) / BPB->BytsPerSec;

//Get Data Start Sector
pVol->FirstDataSec = pVol->VolBeginSec + BPB->RsvdSecCnt +( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt;

//Get Size of Data Area
pVol->DataSecSize = pVol->TotalSec - ( BPB->RsvdSecCnt + ( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt );

//Get Total Cluster Count
pVol->TotalClusCnt = pVol->DataSecSize / BPB->SecPerClus;

//Get Size of Cluster
pVol->ClusterSize = BPB->SecPerClus * BPB->BytsPerSec;

//Get Sector Per Cluster
pVol->SecPerClus = BPB->SecPerClus;

return 1;
}

U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf)
{
U32 ret = 0;
U32 ldistanceLow, ldistanceHigh, dwpointer, bytestoread, numread;

char cur_drv[100];
HANDLE g_hDevice;

sprintf(cur_drv, "\\\\.\\PhysicalDrive%d",(U32)drv);
g_hDevice = CreateFile(cur_drv, GENERIC_READ, FILE_SHARE_READ | FILE_SHARE_WRITE, NULL,
OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0);

if(g_hDevice == INVALID_HANDLE_VALUE) return 0;

ldistanceLow = SecAddr << 9;
ldistanceHigh = SecAddr >> (32 - 9);
dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long *)&ldistanceHigh, FILE_BEGIN);

if(dwpointer != 0xFFFFFFFF)
{
  bytestoread = blocks * 512;
  ret = ReadFile(g_hDevice, buf, bytestoread, (unsigned long*)&numread, NULL);
  if(ret) ret = 1;
  else ret = 0;
}

CloseHandle(g_hDevice);
return ret;
}

< FAT_exam2.c >
#include <stdio.h> #include <windows.h> #include <stdlib.h> #define U8 unsigned char #define S8 char #define U16 unsigned short #define U32 unsigned int #define U64 unsigned __int64 #pragma pack(1) typedef struct _FAT16_BPB_struct{ U8 JmpBoot[3]; U8 OEMName[8]; U16 BytsPerSec; U8 SecPerClus; U16 RsvdSecCnt; U8 NumFATs; U16 RootEntCnt; U16 TotSec16; U8 Media; U16 FATs16; U16 SecPerTrk; U16 NumHeads; U32 HiddSec; U32 TotSec32; //-----공통영역------ U8 DriveNumber; U8 Reserved1; U8 BootSignal; U32 VolumeID; U8 VolumeLabel[11]; U8 FilSysType[8]; //------FAT16영역 U8 BootCodeArea[448]; U16 Signature; }FAT16_BPB; typedef struct _VOL_struct{ U32 Drive; U32 VolBeginSec; U32 FirstDataSec; U32 RootDirSec; U32 RootEntCnt; U32 RootDirSecCnt; U32 FATSize; U32 FATStartSec; U32 TotalClusCnt; U32 TotalSec; U32 DataSecSize; U32 ClusterSize; U32 SecPerClus; }VolStruct; typedef struct _DIR_struct{ U8 Name[11]; U8 Attr; U8 NTRes; U8 CrtTimeTenth; U16 CrtTime; U16 CrtDate; U16 LstAccDate; U16 FstClusHi; U16 WriteTime; U16 WriteDate; U16 FstClusLow; U32 FileSize; }DirEntry; #pragma pack() #pragma pack(1) typedef struct _LONG_DIR_struct{ U8 Order; U8 Name1[10]; U8 Attr; U8 Type; U8 chksum; U8 Name2[12]; U16 FstClusLo; U8 Name3[4]; }LongDirEntry; #pragma pack() void print_longName(LongDirEntry* pLongDir, U32 EntryNum); U32 show_dir (DirEntry* pDir); U32 get_BPB_info(FAT16_BPB* BPB, VolStruct* pVol); U32 HDD_read (U8 drv, U32 SecAddr, U32 blocks, U8* buf); VolStruct gVol; int main(void) { U8 buf[512]; U8* pRootBuf; gVol.Drive = 0x4; gVol.VolBeginSec = 0x0; if( HDD_read(gVol.Drive, gVol.VolBeginSec, 1, buf) == 0 ){ printf("Boot Sector Read Failed \n"); return 1; } if (get_BPB_info((FAT16_BPB)buf, &gVol) == 0){ printf("It is not FAT16 File System \n"); return 1; } pRootBuf = (U8)malloc( gVol.RootDirSecCnt * 512); if( HDD_read(gVol.Drive, gVol.RootDirSec, gVol.RootDirSecCnt, pRootBuf) == 0 ){ printf("Root Dir Read Failed \n"); return 1; } show_dir((DirEntry)pRootBuf); system("pause"); return 0; } U32 show_dir(DirEntry pDir) { U32 i, y, LongEntryEn=0; for(i=0; i<=gVol.RootEntCnt; i++) { switch( (U8) pDir[i].Name[0]){ case 0x00: return 1; // End of Entry case 0xE5: continue; } if(pDir[i].Attr == 0x0F){ LongEntryEn = 1; //Long File Name Entry continue; } printf("---------Entry Number %d ------------ \n", i); if(pDir[i].Attr == 0x10) printf("Directory Name: "); else printf("File Name: "); if(LongEntryEn == 1){ // print long file name print_longName((LongDirEntry)pDir, i-1); LongEntryEn = 0; }else{ //printf short file name for(y=0; y < 11; y++) printf("%c",pDir[i].Name[y]); } printf("\n"); printf("File Size : %d \n",pDir[i].FileSize); printf("Start Cluster : %d \n",(pDir[i].FstClusLow \| pDir[i].FstClusHi << 16) ); } return 1; } void print_longName(LongDirEntry pLongDir, U32 EntryNum) { wchar_t filename[512]; char final[512]; U32 nameOffset = 0; do{ memcpy(&filename[nameOffset],pLongDir[EntryNum].Name1, 10); nameOffset += 5; memcpy(&filename[nameOffset],pLongDir[EntryNum].Name2, 12); nameOffset += 6; memcpy(&filename[nameOffset],pLongDir[EntryNum].Name3, 4 ); nameOffset += 2; }while( (pLongDir[EntryNum--].Order & 0x40) == 0 ); filename[nameOffset] = 0x0000; wcstombs( final, filename, 512 ); printf( "%s", final ); } U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf) { U32 ret = 0; U32 ldistanceLow, ldistanceHigh, dwpointer, bytestoread, numread; char cur_drv[100]; HANDLE g_hDevice; sprintf(cur_drv, "\\\\.\\PhysicalDrive%d",(U32)drv); g_hDevice = CreateFile(cur_drv, GENERIC_READ, FILE_SHARE_READ \| FILE_SHARE_WRITE, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, 0); if(g_hDevice == INVALID_HANDLE_VALUE) return 0; ldistanceLow = SecAddr << 9; ldistanceHigh = SecAddr >> (32 - 9); dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long )&ldistanceHigh, FILE_BEGIN); if(dwpointer != 0xFFFFFFFF) { bytestoread = blocks 512; ret = ReadFile(g_hDevice, buf, bytestoread, (unsigned long)&numread, NULL); if(ret) ret = 1; else ret = 0; } CloseHandle(g_hDevice); return ret; } U32 get_BPB_info(FAT16_BPB BPB, VolStruct* pVol) { if(BPB->RootEntCnt == 0 \|\| BPB->Signature != 0xAA55) { return 0; } //Get Total Sector if( BPB->TotSec16 != 0 ) { pVol->TotalSec = BPB->TotSec16; } else { pVol->TotalSec = BPB->TotSec32; } //Get FAT Size pVol->FATSize = BPB->FATs16; //Get FAT Start Sector pVol->FATStartSec = pVol->VolBeginSec + BPB->RsvdSecCnt; //Get Root Dir Entry Count pVol->RootEntCnt = BPB->RootEntCnt; //Get Root Dir Sector pVol->RootDirSec = pVol->VolBeginSec + BPB->RsvdSecCnt + (BPB->NumFATs * BPB->FATs16); //Get Root Dir Sector Count pVol->RootDirSecCnt = (( BPB->RootEntCnt * 32) + (BPB->BytsPerSec - 1)) / BPB->BytsPerSec; //Get Data Start Sector pVol->FirstDataSec = pVol->VolBeginSec + BPB->RsvdSecCnt +( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt; //Get Size of Data Area pVol->DataSecSize = pVol->TotalSec - ( BPB->RsvdSecCnt + ( BPB->NumFATs * pVol->FATSize ) + pVol->RootDirSecCnt ); //Get Total Cluster Count pVol->TotalClusCnt = pVol->DataSecSize / BPB->SecPerClus; //Get Size of Cluster pVol->ClusterSize = BPB->SecPerClus * BPB->BytsPerSec; //Get Sector Per Cluster pVol->SecPerClus = BPB->SecPerClus; return 1; }

< FAT_exam2.c >

#include <stdio.h>
#include <windows.h>
#include <stdlib.h>

#define U8 unsigned char
#define S8 char
#define U16 unsigned short
#define U32 unsigned int
#define U64 unsigned __int64

#pragma pack(1)
typedef struct _FAT16_BPB_struct{
U8  JmpBoot[3];
U8  OEMName[8];
U16  BytsPerSec;
U8  SecPerClus;
U16  RsvdSecCnt;
U8  NumFATs;
U16  RootEntCnt;
U16  TotSec16;
U8  Media;
U16  FATs16;
U16  SecPerTrk;
U16  NumHeads;
U32  HiddSec;
U32  TotSec32;
//-----공통영역------
U8  DriveNumber;
U8  Reserved1;
U8  BootSignal;
U32  VolumeID;
U8  VolumeLabel[11];
U8  FilSysType[8];
//------FAT16영역

U8 BootCodeArea[448];

U16 Signature;
}FAT16_BPB;

typedef struct _DIR_struct{
  U8  Name[11];
  U8  Attr;
  U8  NTRes;
  U8  CrtTimeTenth;
  U16  CrtTime;
  U16  CrtDate;
  U16  LstAccDate;
  U16  FstClusHi;
  U16  WriteTime;
  U16  WriteDate;
  U16  FstClusLow;
  U32  FileSize;
}DirEntry;
#pragma pack()

#pragma pack(1)
typedef struct _LONG_DIR_struct{
  U8  Order;
  U8  Name1[10];
  U8  Attr;
  U8  Type;
  U8  chksum;
  U8  Name2[12];
  U16  FstClusLo;
  U8  Name3[4];
}LongDirEntry;
#pragma pack()

void print_longName(LongDirEntry* pLongDir, U32 EntryNum);
U32 show_dir (DirEntry* pDir);
U32 get_BPB_info(FAT16_BPB* BPB, VolStruct* pVol);
U32 HDD_read (U8 drv, U32 SecAddr, U32 blocks, U8* buf);

VolStruct gVol;

int main(void) {
  U8      buf[512];
  U8*      pRootBuf;

  gVol.Drive  = 0x4;
  gVol.VolBeginSec = 0x0;

  if( HDD_read(gVol.Drive, gVol.VolBeginSec, 1, buf) == 0 ){
   printf("Boot Sector Read Failed \n");
   return 1;
  }

  if (get_BPB_info((FAT16_BPB*)buf, &gVol) == 0){
   printf("It is not FAT16 File System \n");
   return 1;
  }

  pRootBuf = (U8*)malloc( gVol.RootDirSecCnt * 512);

  if( HDD_read(gVol.Drive, gVol.RootDirSec, gVol.RootDirSecCnt, pRootBuf) == 0 ){
   printf("Root Dir Read Failed \n");
   return 1;
  }

  show_dir((DirEntry*)pRootBuf);
system("pause");
  return 0;
}

U32 show_dir(DirEntry* pDir) {
  U32 i, y, LongEntryEn=0;

  for(i=0; i<=gVol.RootEntCnt; i++)
  {
   switch( (U8) pDir[i].Name[0]){
    case 0x00: return 1; // End of Entry
    case 0xE5: continue;
   }

   if(pDir[i].Attr == 0x0F){
    LongEntryEn = 1;       //Long File Name Entry
    continue;
   }

   printf("---------Entry Number %d ------------ \n", i);

  if(pDir[i].Attr == 0x10) printf("Directory Name: ");
  else                       printf("File Name: ");

   if(LongEntryEn == 1){   // print long file name
    print_longName((LongDirEntry*)pDir, i-1);
    LongEntryEn = 0;
   }else{                     //printf short file name
    for(y=0; y < 11; y++)
     printf("%c",pDir[i].Name[y]);
   }
   printf("\n");
   printf("File Size     : %d \n",pDir[i].FileSize);
   printf("Start Cluster : %d \n",(pDir[i].FstClusLow | pDir[i].FstClusHi << 16) );
  }
  return 1;
}

void print_longName(LongDirEntry* pLongDir, U32 EntryNum)
{
  wchar_t filename[512];
  char  final[512];
  U32  nameOffset = 0;

  do{
   memcpy(&filename[nameOffset],pLongDir[EntryNum].Name1, 10); nameOffset += 5;
   memcpy(&filename[nameOffset],pLongDir[EntryNum].Name2, 12); nameOffset += 6;
   memcpy(&filename[nameOffset],pLongDir[EntryNum].Name3, 4 ); nameOffset += 2;
  }while( (pLongDir[EntryNum--].Order & 0x40) == 0 );

  filename[nameOffset] = 0x0000;

  wcstombs( final, filename, 512 );
     printf( "%s", final );
}