Read disk sector on Windows

關鍵在於磁碟機代號的名字，假設是 D 槽，其名字為 "\\.\D:"
至於是用 Win32 API or C code 實驗結果都一樣
故只要稍微修改一下，便可以用來讀指定的 NTFS Entry

當然我們也可以讀取實體的硬碟開頭，只要遵循以下規則

Name	Meaning
\\.\PhysicalDrive0	電腦的第 1 顆硬碟
\\.\PhysicalDrive1	電腦的第 2 顆硬碟
\\.\c:	電腦的 C 槽
\\.\c:\	電腦的 C 槽 file system

#include <stdio.h>
#include <mem.h>
//-----------------------------------------------------------------------------
#define SECTOR_SIZE         512
//---------------------------------------------------------------------------
// num is sector number, it starts with 0
bool ReadSect(const char *dsk, char *buf, int num)
{
    if (strlen(dsk) == 0) {
        return false;
    }

    if (num < 0) {
        return false;
    }

    FILE *f = fopen(dsk, "rb");
    if (!f) {
        return false;
    }

    fseek(f, num * SECTOR_SIZE, SEEK_SET);

    fread(buf, SECTOR_SIZE, 1, f);

    fclose(f);

    return true;
}
//---------------------------------------------------------------------------
int main(void)
{
    char drv[64];
    memset(drv, 0x00, sizeof(drv));

    char disk;
    printf("Which disk do you want to read ?   ");
    scanf("%c", &disk);

    unsigned int sector;
    printf("Which sector do you want to read ? ");
    scanf("%d", &sector);
    printf("\r\n");

    // use "\\.\PhysicalDrive" to read
    sprintf(drv, "\\\\.\\%c:", disk);

    char buf[SECTOR_SIZE];
    ReadSect(drv, buf, sector);

    int line = 0;
    for (int i = 0; i < SECTOR_SIZE; i++) {
        if (line == 0) {
            printf("0x%04X  ", sector * SECTOR_SIZE + (i/16) * 16);
        }

        printf("%02X ", (unsigned char)buf[i]);

        line++;

        if (line == 16) {
            printf("\n");
            line = 0;
        }
    }

    printf("\n");
    return 0;
}