#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;
//------------
U8 DriverNumber;
U8 Reserved1;
U8 BootSignal;
U32 VolumID;
U8 VolumeLabel[11];
U8 FileSysType[8];
//------------ FAT16
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;
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 ()
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;
void print_longName(LongDirEntry *pLongDir, U32 EntryNum);
U32 show_dir(DirEntry *pDir);
U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8 *buf);
U32 Get_BPB_info(FAT16_BPB *BPB, VolStruct *pVol);
void HexDump(U8 *addr, U32 len);
VolStruct gVol;
int main(void)
{
U8 buf[512];
U8 *pRootBuf;
U32 MyBr;
gVol.Drive = 0x1;
gVol.VolBeginSec = 0x0;
HDD_read(gVol.Drive, gVol.VolBeginSec, 1, buf); // 나의 USB에는 MBR이 있음
MyBr = *((unsigned int *)(buf + 446 + 8));
HDD_read(gVol.Drive, MyBr , 1, buf); // 그래서 BR부분을 한번 더 읽어야 함
if(0 == Get_BPB_info((FAT16_BPB *)buf, &gVol)) // FAT16이 아닐경우 0이 돌아오면서 종료
{
printf("It is not FAT16 File System \n");
return 1;
}
pRootBuf = (U8 *)malloc(gVol.RootDirSecCnt * 512); // 동적할당을 받는다
if(0 == HDD_read(gVol.Drive, MyBr + gVol.RootDirSec, gVol.RootDirSecCnt, pRootBuf))
{
printf("Root Dir Read Failed\n");
free(pRootBuf);
return 1;
}
show_dir((DirEntry *)pRootBuf);
free(pRootBuf);
return 0;
}
U32 show_dir(DirEntry *pDir)
{
U32 i;
U32 y;
U32 LongEntryEn = 0;
for(i = 0;i <= gVol.RootEntCnt;i++)
{
switch( (U8)pDir[i].Name[0])
{
case 0x00:
return 1;
case 0xE5:
continue;
}
if(0x0F == pDir[i].Attr)
{
LongEntryEn = 1;
continue;
}
printf("--------Entry Number %d--------\n", i);
if(0x10 == pDir[i].Attr)
{
printf("Directory Name : ");
}
else
{
printf("File Name : ");
}
if(1 == LongEntryEn)
{
print_longName((LongDirEntry *)pDir, i-1);
LongEntryEn = 0;
}
else
{
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 = nameOffset + 5;
memcpy(&filename[nameOffset], pLongDir[EntryNum].Name2, 12);
nameOffset = nameOffset + 6;
memcpy(&filename[nameOffset], pLongDir[EntryNum].Name3, 4);
nameOffset = nameOffset + 2;
}while( 0 == (pLongDir[EntryNum--].Order & 0x40) );
filename[nameOffset] = 0x0000;
wcstombs(final, filename, 512);
printf("%s", final);
return ;
}
U32 Get_BPB_info(FAT16_BPB *BPB, VolStruct *pVol)
{
if( 0 == BPB->RootEntCnt || 0xAA55 != BPB->Signature )
{
return 0;
}
if( 0 != BPB->TotSec16 )
{
pVol->TotalSec = BPB->TotSec16;
}
else
{
pVol->TotalSec = BPB->TotSec32;
}
pVol->FATSize = BPB->FATs16; // FAT영역의 섹터 수
pVol->FATStartSec = pVol->VolBeginSec + BPB->RsvdSecCnt; // 루트 디렉토리의 Directory Entry 개수
pVol->RootEntCnt = BPB->RootEntCnt; // 루트디렉토리 시작섹터
pVol->RootDirSec = pVol->VolBeginSec + BPB->RsvdSecCnt + (BPB->NumFATs * BPB->FATs16);
pVol->RootDirSecCnt = ((BPB->RootEntCnt * 32) + (BPB->BytsPerSec - 1)) / BPB->BytsPerSec; // 루트디렉토리의 섹터수
pVol->FirstDataSec = pVol->VolBeginSec + BPB->RsvdSecCnt + (BPB->NumFATs * pVol->FATSize) + pVol->RootDirSecCnt; // 첫번째 데이터 섹터를 구하는 코드
pVol->DataSecSize = pVol->TotalSec - (BPB->RsvdSecCnt + (BPB->NumFATs * pVol->FATSize) + pVol->RootDirSecCnt); // 데이터 영역의 섹터 수
pVol->TotalClusCnt = pVol->DataSecSize / BPB->SecPerClus; // 볼륨의 총 클러스터 개수
pVol->ClusterSize = BPB->SecPerClus * BPB->BytsPerSec; // 클러스터의 크기
pVol->SecPerClus = BPB->SecPerClus; // 클러스터가 몇 개의 섹터를 차지하는가
return 1;
}
U32 HDD_read(U8 drv, U32 SecAddr, U32 blocks, U8* buf)
{
U32 ret;
U32 ldistanceLow;
U32 ldistanceHigh;
U32 dwpointer;
U32 bytestoread;
U32 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); // 하드드라이버 연다
if(g_hDevice == INVALID_HANDLE_VALUE) // 에러 체크
{
return 0;
}
ldistanceLow = SecAddr << 9;
ldistanceHigh = SecAddr >> (32 - 9);
dwpointer = SetFilePointer(g_hDevice, ldistanceLow, (long *)&ldistanceHigh, FILE_BEGIN); // 파일포인터를 이동시킨다 (제일 처음으로)
// FILE_BEGIN 제일 처음으로 이동 (win32표준 :: lseek)
if(0xFFFFFFFF != dwpointer) // -1인지 체크
{
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;
}
void HexDump(U8 *addr, U32 len)
{
U8 *s = addr;
U8 *endPtr = (U8 *)((U32)addr+len);
U32 i;
U32 remainder = len%16;
printf("\n Offset Hex Value Ascii value\n");
while(s+16 <= endPtr)
{
printf("0x%08LX ", (long)(s-addr));
for(i = 0;i < 16;i++)
{
printf("%02X ", s[i]);
}
printf(" ");
for(i = 0;i < 16;i++)
{
if(s[i] >= 32 && s[i] <= 125)
{
printf("%c", s[i]);
}
else
{
printf(".");
}
}
s = s + 16;
printf("\n");
}
if(remainder)
{
printf("0x08LX ", (long)(s-addr));
for(i = 0;i < remainder;i++)
{
printf("%02X ", s[i]);
}
for(i = 0;i < (16-remainder);i++)
{
printf(" ");
}
printf(" ");
for(i = 0;i < remainder;i++)
{
if(s[i] >= 32 && s[i] <= 125)
{
printf("%c", s[i]);
}
else
{
printf(".");
}
}
for(i = 0;i < (16 - remainder);i++)
{
printf(" ");
}
printf("\n");
}
return ;
}
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FAT_exam2.c