這是上學期操作系統的期末課程設計作業之一，主要功能是在物理內存中虛擬出一個1M大小的FAT16的文件系統，然後把它讀入內存中,進行具體的文件操作,具體的實用性不大，主要目的是爲了練習C語言,幫助理解文件系統的特點,代碼如下：
#include <stdio.h>
#include <malloc.h>
#include <string.h>
#include <time.h>
#define BLOCKSIZE 1024 // 磁盤塊大小
#define SIZE 1024000 // 虛擬磁盤空間大小
#define END 65535 // FAT中的文件結束標誌
#define FREE 0 // FAT中盤塊空閒標誌
#define ROOTBLOCKNUM 2 // 根目錄區所佔盤塊數
#define MAXOPENFILE 10 // 最多同時打開文件個數t
#define MAXTEXT 10000
/* 文件控制塊 */
typedef struct FCB
{
char filename[8]; // 文件名
char exname[3]; // 文件擴展名
unsigned char attribute; // 文件屬性字段，值爲0時表示目錄文件，值爲1時表示數據文件
unsigned short time; // 文件創建時間
unsigned short date; // 文件創建日期
unsigned short first; // 文件起始盤塊號
unsigned long length; // 文件長度
char free; // 表示目錄項是否爲空，若值爲0，表示空，值爲1，表示已分配
}fcb;
/* 文件分配表 */
typedef struct FAT
{
unsigned short id; // 磁盤塊的狀態（空閒的，最後的，下一個）
}fat;
/* 用戶打開文件表 */
typedef struct USEROPEN
{
char filename[8]; // 文件名
char exname[3]; // 文件擴展名
unsigned char attribute; // 文件屬性字段，值爲0時表示目錄文件，值爲1時表示數據文件
unsigned short time; // 文件創建時間
unsigned short date; // 文件創建日期
unsigned short first; // 文件起始盤塊號
unsigned long length; // 文件長度（對數據文件是字節數，對目錄文件可以是目錄項個數）
char free; // 表示目錄項是否爲空，若值爲0，表示空，值爲1，表示已分配
unsigned short dirno; // 相應打開文件的目錄項在父目錄文件中的盤塊號
int diroff; // 相應打開文件的目錄項在父目錄文件的dirno盤塊中的目錄項序號
char dir[80]; // 相應打開文件所在的目錄名，這樣方便快速檢查出指定文件是否已經打開
int father; // 父目錄在打開文件表項的位置
int count; // 讀寫指針在文件中的位置,文件的總字符數
char fcbstate; // 是否修改了文件的FCB的內容，如果修改了置爲1，否則爲0
char topenfile; // 表示該用戶打開表項是否爲空，若值爲0，表示爲空，否則表示已被某打開文件佔據
}useropen;
/* 引導塊 */
typedef struct BLOCK0
{
char magic[10]; // 文件系統魔數
char information[200]; // 存儲一些描述信息，如磁盤塊大小、磁盤塊數量、最多打開文件數等
unsigned short root; // 根目錄文件的起始盤塊號
unsigned char *startblock; // 虛擬磁盤上數據區開始位置
}block0;
unsigned char *myvhard; // 指向虛擬磁盤的起始地址
useropen openfilelist[MAXOPENFILE]; // 用戶打開文件表數組
int curdir; // 用戶打開文件表中的當前目錄所在打開文件表項的位置
char currentdir[80]; // 記錄當前目錄的目錄名（包括目錄的路徑）
unsigned char* startp; // 記錄虛擬磁盤上數據區開始位置
char myfilename[] = "myfilesys";//文件系統的文件名
void startsys(); // 進入文件系統
void my_format(); // 磁盤格式化
void my_cd(char *dirname); // 更改當前目錄
void my_mkdir(char *dirname); // 創建子目錄
void my_rmdir(char *dirname); // 刪除子目錄
void my_ls(); // 顯示目錄
void my_create (char *filename); // 創建文件
void my_rm(char *filename); // 刪除文件
int my_open(char *filename); // 打開文件
int my_close(int fd); // 關閉文件
int my_write(int fd); // 寫文件
int do_write(int fd, char *text, int len, char wstyle); // 實際寫文件
int my_read (int fd, int len); // 讀文件
int do_read (int fd, int len,char *text); // 實際讀文件
void my_exitsys(); // 退出文件系統
unsigned short findblock(); // 尋找空閒盤塊
int findopenfile(); // 尋找空閒文件表項
void startsys()
{
FILE *fp;
unsigned char buf[SIZE];
fcb *root;
int i;
myvhard = (unsigned char *)malloc(SIZE);//申請虛擬磁盤空間
memset(myvhard, 0, SIZE);//將myvhard中前SIZE個字節用 0 替換並返回 myvhard
if((fp = fopen(myfilename, "r")) != NULL)
{
fread(buf, SIZE, 1, fp);//將二進制文件讀取到緩衝區
fclose(fp);//關閉打開的文件，緩衝區數據寫入文件，釋放系統提供文件資源
if(strcmp(((block0 *)buf)->magic, "10101010"))//判斷開始的8個字節內容是否爲文件系統魔數
{
printf("myfilesys is not exist,begin to creat the file...\n");
my_format();
}
else
{
for(i = 0; i < SIZE; i++)
myvhard[i] = buf[i];
}
}
else
{
printf("myfilesys is not exist,begin to creat the file...\n");
my_format();
}
root = (fcb *)(myvhard + 5 * BLOCKSIZE);
strcpy(openfilelist[0].filename, root->filename);
strcpy(openfilelist[0].exname, root->exname);
openfilelist[0].attribute = root->attribute;
openfilelist[0].time = root->time;
openfilelist[0].date = root->date;
openfilelist[0].first = root->first;
openfilelist[0].length = root->length;
openfilelist[0].free = root->free;
openfilelist[0].dirno = 5;
openfilelist[0].diroff = 0;
strcpy(openfilelist[0].dir, "\\root\\");
openfilelist[0].father = 0;
openfilelist[0].count = 0;
openfilelist[0].fcbstate = 0;
openfilelist[0].topenfile = 1;
for(i = 1; i < MAXOPENFILE; i++)
openfilelist[i].topenfile = 0;
curdir = 0;
strcpy(currentdir, "\\root\\");
startp = ((block0 *)myvhard)->startblock;
}
void my_format()
{
FILE *fp;
fat *fat1, *fat2;
block0 *blk0;
time_t now;
struct tm *nowtime;
fcb *root;
int i;
blk0 = (block0 *)myvhard;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
root = (fcb *)(myvhard + 5 * BLOCKSIZE);
strcpy(blk0->magic, "10101010");
strcpy(blk0->information, "My FileSystem Ver 1.0 \n Blocksize=1KB Whole size=1000KB Blocknum=1000 RootBlocknum=2\n");
blk0->root = 5;
blk0->startblock = (unsigned char *)root;
for(i = 0; i < 5; i++)
{
fat1->id = END;
fat2->id = END;
fat1++;
fat2++;
}
fat1->id = 6;
fat2->id = 6;
fat1++;
fat2++;
fat1->id = END;
fat2->id = END;
fat1++;
fat2++;
for(i = 7; i < SIZE / BLOCKSIZE; i++)
{
fat1->id = FREE;
fat2->id = FREE;
fat1++;
fat2++;
}
now = time(NULL);
nowtime = localtime(&now);
strcpy(root->filename, ".");
strcpy(root->exname, "");
root->attribute = 0x28;
root->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
root->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
root->first = 5;
root->length = 2 * sizeof(fcb);
root->free = 1;
root++;
now = time(NULL);
nowtime = localtime(&now);
strcpy(root->filename, "..");
strcpy(root->exname, "");
root->attribute = 0x28;
root->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
root->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
root->first = 5;
root->length = 2 * sizeof(fcb);
root->free = 1;
fp = fopen(myfilename, "w");
fwrite(myvhard, SIZE, 1, fp);
fclose(fp);
}
void my_cd(char *dirname)
{
char *dir;
int fd;
dir = strtok(dirname, "\\");//分解字符串爲一組字符串。dirname爲要分解的字符串，"\\"爲分隔符字符串
if(strcmp(dir, ".") == 0)
return;
else if(strcmp(dir, "..") == 0)
{
if(curdir)
curdir = my_close(curdir);
return;
}
else if(strcmp(dir, "root") == 0)
{
while(curdir)
curdir = my_close(curdir);
dir = strtok(NULL, "\\");
}
while(dir)
{
fd = my_open(dir);
if(fd != -1)
curdir = fd;
else
return;
dir = strtok(NULL, "\\");
}
}
void my_mkdir(char *dirname)
{
fcb *fcbptr;
fat *fat1, *fat2;
time_t now;
struct tm *nowtime;
char text[MAXTEXT];
unsigned short blkno;
int rbn, fd, i;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)//在當前目錄下找，是否有重名目錄
{
if(strcmp(fcbptr->filename, dirname) == 0 && strcmp(fcbptr->exname, "") == 0)
{
printf("Error,the dirname is already exist!\n");
return;
}
fcbptr++;
}
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(fcbptr->free == 0)
break;
fcbptr++;
}
blkno = findblock();//尋找空閒盤塊
if(blkno == -1)
return;
(fat1 + blkno)->id = END;
(fat2 + blkno)->id = END;
now = time(NULL);
nowtime = localtime(&now);
strcpy(fcbptr->filename, dirname);
strcpy(fcbptr->exname, "");
fcbptr->attribute = 0x30;
fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
fcbptr->first = blkno;
fcbptr->length = 2 * sizeof(fcb);
fcbptr->free = 1;
openfilelist[curdir].count = i * sizeof(fcb);
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
fd = my_open(dirname);//建立新目錄的'.','..'目錄
if(fd == -1)
return;
fcbptr = (fcb *)malloc(sizeof(fcb));
now = time(NULL);
nowtime = localtime(&now);
strcpy(fcbptr->filename, ".");
strcpy(fcbptr->exname, "");
fcbptr->attribute = 0x28;
fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
fcbptr->first = blkno;
fcbptr->length = 2 * sizeof(fcb);
fcbptr->free = 1;
do_write(fd, (char *)fcbptr, sizeof(fcb), 2);
now = time(NULL);
nowtime = localtime(&now);
strcpy(fcbptr->filename, "..");
strcpy(fcbptr->exname, "");
fcbptr->attribute = 0x28;
fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
fcbptr->first = blkno;
fcbptr->length = 2 * sizeof(fcb);
fcbptr->free = 1;
do_write(fd, (char *)fcbptr, sizeof(fcb), 2);
free(fcbptr);
my_close(fd);
fcbptr = (fcb *)text;
fcbptr->length = openfilelist[curdir].length;
openfilelist[curdir].count = 0;
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
openfilelist[curdir].fcbstate = 1;
}
void my_rmdir(char *dirname)
{
fcb *fcbptr,*fcbptr2;
fat *fat1, *fat2, *fatptr1, *fatptr2;
char text[MAXTEXT], text2[MAXTEXT];
unsigned short blkno;
int rbn, rbn2, fd, i, j;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
if(strcmp(dirname, ".") == 0 || strcmp(dirname, "..") == 0)
{
printf("Error,can't remove this directory.\n");
return;
}
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)//查找要刪除的目錄
{
if(strcmp(fcbptr->filename, dirname) == 0 && strcmp(fcbptr->exname, "") == 0)
break;
fcbptr++;
}
if(i == rbn / sizeof(fcb))
{
printf("Error,the directory is not exist.\n");
return;
}
fd = my_open(dirname);
rbn2 = do_read(fd, openfilelist[fd].length, text2);
fcbptr2 = (fcb *)text2;
for(j = 0; j < rbn2 / sizeof(fcb); j++)//判斷要刪除目錄是否爲空
{
if(strcmp(fcbptr2->filename, ".") && strcmp(fcbptr2->filename, "..") && strcmp(fcbptr2->filename, ""))
{
my_close(fd);
printf("Error,the directory is not empty.\n");
return;
}
fcbptr2++;
}
blkno = openfilelist[fd].first;
while(blkno != END)
{
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
blkno = fatptr1->id;
fatptr1->id = FREE;
fatptr2->id = FREE;
}
my_close(fd);
strcpy(fcbptr->filename, "");
fcbptr->free = 0;
openfilelist[curdir].count = i * sizeof(fcb);
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
openfilelist[curdir].fcbstate = 1;
}
void my_ls()
{
fcb *fcbptr;
char text[MAXTEXT];
int rbn, i;
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(fcbptr->free)
{
if(fcbptr->attribute & 0x20)
printf("%s\\\t\t<DIR>\t\t%d/%d/%d\t%02d:%02d:%02d\n", fcbptr->filename, (fcbptr->date >> 9) + 1980, (fcbptr->date >> 5) & 0x000f, fcbptr->date & 0x001f, fcbptr->time >> 11, (fcbptr->time >> 5) & 0x003f, fcbptr->time & 0x001f * 2);
else
printf("%s.%s\t\t%dB\t\t%d/%d/%d\t%02d:%02d:%02d\t\n", fcbptr->filename, fcbptr->exname, (int)(fcbptr->length), (fcbptr->date >> 9) + 1980, (fcbptr->date >> 5) & 0x000f, fcbptr->date & 0x1f, fcbptr->time >> 11, (fcbptr->time >> 5) & 0x3f, fcbptr->time & 0x1f * 2);
}
fcbptr++;
}
}
void my_create(char *filename)
{
fcb *fcbptr;
fat *fat1, *fat2;
char *fname, *exname, text[MAXTEXT];
unsigned short blkno;
int rbn, i;
time_t now;
struct tm *nowtime;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + BLOCKSIZE);
fname = strtok(filename, ".");
exname = strtok(NULL, ".");
if(strcmp(fname, "") == 0)
{
printf("Error,creating file must have a right name.\n");
return;
}
if(!exname)
{
printf("Error,creating file must have a extern name.\n");
return;
}
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)
{
printf("Error,the filename is already exist!\n");
return;
}
fcbptr++;
}
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(fcbptr->free == 0)
break;
fcbptr++;
}
blkno = findblock();
if(blkno == -1)
return;
(fat1 + blkno)->id = END;
(fat2 + blkno)->id = END;
now = time(NULL);
nowtime = localtime(&now);
strcpy(fcbptr->filename, fname);
strcpy(fcbptr->exname, exname);
fcbptr->attribute = 0x00;
fcbptr->time = nowtime->tm_hour * 2048 + nowtime->tm_min * 32 + nowtime->tm_sec / 2;
fcbptr->date = (nowtime->tm_year - 80) * 512 + (nowtime->tm_mon + 1) * 32 + nowtime->tm_mday;
fcbptr->first = blkno;
fcbptr->length = 0;
fcbptr->free = 1;
openfilelist[curdir].count = i * sizeof(fcb);
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
fcbptr = (fcb *)text;
fcbptr->length = openfilelist[curdir].length;
openfilelist[curdir].count = 0;
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
openfilelist[curdir].fcbstate = 1;
}
void my_rm(char *filename)
{
fcb *fcbptr;
fat *fat1, *fat2, *fatptr1, *fatptr2;
char *fname, *exname, text[MAXTEXT];
unsigned short blkno;
int rbn, i;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
fname = strtok(filename, ".");
exname = strtok(NULL, ".");
if(strcmp(fname, "") == 0)
{
printf("Error,removing file must have a right name.\n");
return;
}
if(!exname)
{
printf("Error,removing file must have a extern name.\n");
return;
}
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)
break;
fcbptr++;
}
if(i == rbn / sizeof(fcb))
{
printf("Error,the file is not exist.\n");
return;
}
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)
break;
fcbptr++;
}
if(i == rbn / sizeof(fcb))
{
printf("Error,the file is not exist.\n");
return;
}
blkno = fcbptr->first;
while(blkno != END)
{
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
blkno = fatptr1->id;
fatptr1->id = FREE;
fatptr2->id = FREE;
}
strcpy(fcbptr->filename, "");
fcbptr->free = 0;
openfilelist[curdir].count = i * sizeof(fcb);
do_write(curdir, (char *)fcbptr, sizeof(fcb), 2);
openfilelist[curdir].fcbstate = 1;
}
int my_open(char *filename)
{
fcb *fcbptr;
char *fname, exname[3], *str, text[MAXTEXT];
int rbn, fd, i;
fname = strtok(filename, ".");
str = strtok(NULL, ".");
if(str)
strcpy(exname, str);
else
strcpy(exname, "");
for(i = 0; i < MAXOPENFILE; i++)
{
if(strcmp(openfilelist[i].filename, fname) == 0 && strcmp(openfilelist[i].exname, exname) == 0 && i != curdir)
{
printf("Error,the file is already open.\n");
return -1;
}
}
openfilelist[curdir].count = 0;
rbn = do_read(curdir, openfilelist[curdir].length, text);
fcbptr = (fcb *)text;
for(i = 0; i < rbn / sizeof(fcb); i++)
{
if(strcmp(fcbptr->filename, fname) == 0 && strcmp(fcbptr->exname, exname) == 0)
break;
fcbptr++;
}
if(i == rbn / sizeof(fcb))
{
printf("Error,the file is not exist.\n");
return -1;
}
fd = findopenfile();
if(fd == -1)
return -1;
strcpy(openfilelist[fd].filename, fcbptr->filename);
strcpy(openfilelist[fd].exname, fcbptr->exname);
openfilelist[fd].attribute = fcbptr->attribute;
openfilelist[fd].time = fcbptr->time;
openfilelist[fd].date = fcbptr->date;
openfilelist[fd].first = fcbptr->first;
openfilelist[fd].length = fcbptr->length;
openfilelist[fd].free = fcbptr->free;
openfilelist[fd].dirno = openfilelist[curdir].first;
openfilelist[fd].diroff = i;
strcpy(openfilelist[fd].dir, openfilelist[curdir].dir);
strcat(openfilelist[fd].dir, filename);
if(fcbptr->attribute & 0x20)
strcat(openfilelist[fd].dir, "\\");
openfilelist[fd].father = curdir;
openfilelist[fd].count = 0;
openfilelist[fd].fcbstate = 0;
openfilelist[fd].topenfile = 1;
return fd;
}
int my_close(int fd)
{
fcb *fcbptr;
int father;
if(fd < 0 || fd >= MAXOPENFILE)
{
printf("Error,the file is not exist.\n");
return -1;
}
if(openfilelist[fd].fcbstate)
{
fcbptr = (fcb *)malloc(sizeof(fcb));
strcpy(fcbptr->filename, openfilelist[fd].filename);
strcpy(fcbptr->exname, openfilelist[fd].exname);
fcbptr->attribute = openfilelist[fd].attribute;
fcbptr->time = openfilelist[fd].time;
fcbptr->date = openfilelist[fd].date;
fcbptr->first = openfilelist[fd].first;
fcbptr->length = openfilelist[fd].length;
fcbptr->free = openfilelist[fd].free;
father = openfilelist[fd].father;
openfilelist[father].count = openfilelist[fd].diroff * sizeof(fcb);
do_write(father, (char *)fcbptr, sizeof(fcb), 2);
free(fcbptr);
openfilelist[fd].fcbstate = 0;
}
strcpy(openfilelist[fd].filename, "");
strcpy(openfilelist[fd].exname, "");
openfilelist[fd].topenfile = 0;
return father;
}
int my_write(int fd)
{
fat *fat1, *fat2, *fatptr1, *fatptr2;
int wstyle, len, ll, tmp;
char text[MAXTEXT];
unsigned short blkno;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
if(fd < 0 || fd >= MAXOPENFILE)
{
printf("The file is not exist!\n");
return -1;
}
while(1)
{
printf("Please enter the number of write style:\n1.cut write\t2.cover write\t3.add write\n");
scanf("%d", &wstyle);
if(wstyle > 0 && wstyle < 4)
break;
printf("Input Error!");
}
getchar();
switch(wstyle)
{
case 1:
blkno = openfilelist[fd].first;
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
blkno = fatptr1->id;
fatptr1->id = END;
fatptr2->id = END;
while(blkno != END)
{
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
blkno = fatptr1->id;
fatptr1->id = FREE;
fatptr2->id = FREE;
}
openfilelist[fd].count = 0;
openfilelist[fd].length = 0;
break;
case 2:
openfilelist[fd].count = 0;
break;
case 3:
openfilelist[fd].count = openfilelist[fd].length;
break;
default:
break;
}
ll = 0;
printf("please input write data(end with Ctrl+Z):\n");
while(gets(text))
{
len = strlen(text);
text[len++] = '\n';
text[len] = '\0';
tmp = do_write(fd, text, len, wstyle);
if(tmp != -1)
ll += tmp;
if(tmp < len)
{
printf("Wirte Error!");
break;
}
}
return ll;
}
int do_write(int fd, char *text, int len, char wstyle)
{
fat *fat1, *fat2, *fatptr1, *fatptr2;
unsigned char *buf, *blkptr;
unsigned short blkno, blkoff;
int i, ll;
fat1 = (fat *)(myvhard + BLOCKSIZE);
fat2 = (fat *)(myvhard + 3 * BLOCKSIZE);
buf = (unsigned char *)malloc(BLOCKSIZE);
if(buf == NULL)
{
printf("malloc failed!\n");
return -1;
}
blkno = openfilelist[fd].first;
blkoff = openfilelist[fd].count;
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
while(blkoff >= BLOCKSIZE)
{
blkno = fatptr1->id;
if(blkno == END)
{
blkno = findblock();
if(blkno == -1)
{
free(buf);
return -1;
}
fatptr1->id = blkno;
fatptr2->id = blkno;
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
fatptr1->id = END;
fatptr2->id = END;
}
else
{
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
}
blkoff = blkoff - BLOCKSIZE;
}
ll = 0;
while(ll < len)
{
blkptr = (unsigned char *)(myvhard + blkno * BLOCKSIZE);
for(i = 0; i < BLOCKSIZE; i++)
buf[i] = blkptr[i];
for(;blkoff < BLOCKSIZE; blkoff++)
{
buf[blkoff] = text[ll++];
openfilelist[fd].count++;
if(ll == len)
break;
}
for(i = 0; i < BLOCKSIZE; i++)
blkptr[i] = buf[i];
if(ll < len)
{
blkno = fatptr1->id;
if(blkno == END)
{
blkno = findblock();
if(blkno == -1)
break;
fatptr1->id = blkno;
fatptr2->id = blkno;
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
fatptr1->id = END;
fatptr2->id = END;
}
else
{
fatptr1 = fat1 + blkno;
fatptr2 = fat2 + blkno;
}
blkoff = 0;
}
}
if(openfilelist[fd].count > openfilelist[fd].length)
openfilelist[fd].length = openfilelist[fd].count;
openfilelist[fd].fcbstate = 1;
free(buf);
return ll;
}
int my_read(int fd, int len)
{
char text[MAXTEXT];
int ll;
if(fd < 0 || fd >= MAXOPENFILE)
{
printf("The File is not exist!\n");
return -1;
}
openfilelist[fd].count = 0;
ll = do_read(fd, len, text);
if(ll != -1)
printf("%s", text);
else
printf("Read Error!\n");
return ll;
}
int do_read(int fd, int len, char *text)
{
fat *fat1, *fatptr;
unsigned char *buf, *blkptr;
unsigned short blkno, blkoff;
int i, ll;
fat1 = (fat *)(myvhard + BLOCKSIZE);
buf = (unsigned char *)malloc(BLOCKSIZE);
if(buf == NULL)
{
printf("malloc failed!\n");
return -1;
}
blkno = openfilelist[fd].first;
blkoff = openfilelist[fd].count;
if(blkoff >= openfilelist[fd].length)
{
puts("Read out of range!");
free(buf);
return -1;
}
fatptr = fat1 + blkno;
while(blkoff >= BLOCKSIZE)
{
blkno = fatptr->id;
blkoff = blkoff - BLOCKSIZE;
fatptr = fat1 + blkno;
}
ll = 0;
while(ll < len)
{
blkptr = (unsigned char *)(myvhard + blkno * BLOCKSIZE);
for(i = 0; i < BLOCKSIZE; i++)
buf[i] = blkptr[i];
for(; blkoff < BLOCKSIZE; blkoff++)
{
text[ll++] = buf[blkoff];
openfilelist[fd].count++;
if(ll == len || openfilelist[fd].count == openfilelist[fd].length)
break;
}
if(ll < len && openfilelist[fd].count != openfilelist[fd].length)
{
blkno = fatptr->id;
if(blkno == END)
break;
blkoff = 0;
fatptr = fat1 + blkno;
}
}
text[ll] = '\0';
free(buf);
return ll;
}
void my_exitsys()
{
FILE *fp;
while(curdir)
curdir = my_close(curdir);
fp = fopen(myfilename, "w");
fwrite(myvhard, SIZE, 1, fp);
fclose(fp);
free(myvhard);
}
unsigned short findblock()
{
unsigned short i;
fat *fat1, *fatptr;
fat1 = (fat *)(myvhard + BLOCKSIZE);
for(i = 7; i < SIZE / BLOCKSIZE; i++)
{
fatptr = fat1 + i;
if(fatptr->id == FREE)
return i;
}
printf("Error,Can't find free block!\n");
return -1;
}
int findopenfile()
{
int i;
for(i = 0; i < MAXTEXT; i++)
{
if(openfilelist[i].topenfile == 0)
return i;
}
printf("Error,open too many files!\n");
return -1;
}
int main()
{
char cmd[15][10] = {"cd", "mkdir", "rmdir", "ls", "create", "rm", "open", "close", "write", "read", "exit"};
char s[30], *sp;
int cmdn, flag = 1, i;
startsys();
printf("*********************File System V1.0*******************************\n\n");
printf("命令名\t\t命令參數\t\t命令說明\n\n");
printf("cd\t\t目錄名(路徑名)\t\t切換當前目錄到指定目錄\n");
printf("mkdir\t\t目錄名\t\t\t在當前目錄創建新目錄\n");
printf("rmdir\t\t目錄名\t\t\t在當前目錄刪除指定目錄\n");
printf("ls\t\t無\t\t\t顯示當前目錄下的目錄和文件\n");
printf("create\t\t文件名\t\t\t在當前目錄下創建指定文件\n");
printf("rm\t\t文件名\t\t\t在當前目錄下刪除指定文件\n");
printf("open\t\t文件名\t\t\t在當前目錄下打開指定文件\n");
printf("write\t\t無\t\t\t在打開文件狀態下，寫該文件\n");
printf("read\t\t無\t\t\t在打開文件狀態下，讀取該文件\n");
printf("close\t\t無\t\t\t在打開文件狀態下，讀取該文件\n");
printf("exit\t\t無\t\t\t退出系統\n\n");
printf("*********************************************************************\n\n");
while(flag)
{
printf("%s>", openfilelist[curdir].dir);
gets(s);
cmdn = -1;
if(strcmp(s, ""))
{
sp=strtok(s, " ");
for(i = 0; i < 15; i++)
{
if(strcmp(sp, cmd[i]) == 0)
{
cmdn = i;
break;
}
}
// printf("%d\n", cmdn);
switch(cmdn)
{
case 0:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
my_cd(sp);
else
printf("Please input the right command.\n");
break;
case 1:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
my_mkdir(sp);
else
printf("Please input the right command.\n");
break;
case 2:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
my_rmdir(sp);
else
printf("Please input the right command.\n");
break;
case 3:
if(openfilelist[curdir].attribute & 0x20)
my_ls();
else
printf("Please input the right command.\n");
break;
case 4:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
my_create(sp);
else
printf("Please input the right command.\n");
break;
case 5:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
my_rm(sp);
else
printf("Please input the right command.\n");
break;
case 6:
sp = strtok(NULL, " ");
if(sp && (openfilelist[curdir].attribute & 0x20))
{
if(strchr(sp, '.'))//查找sp中'.'首次出現的位置
curdir = my_open(sp);
else
printf("the openfile should have exname.\n");
}
else
printf("Please input the right command.\n");
break;
case 7:
if(!(openfilelist[curdir].attribute & 0x20))
curdir = my_close(curdir);
else
printf("No files opened.\n");
break;
case 8:
if(!(openfilelist[curdir].attribute & 0x20))
my_write(curdir);
else
printf("No files opened.\n");
break;
case 9:
if(!(openfilelist[curdir].attribute & 0x20))
my_read(curdir, openfilelist[curdir].length);
else
printf("No files opened.\n");
break;
case 10:
if(openfilelist[curdir].attribute & 0x20)
{
my_exitsys();
flag = 0;
}
else
printf("Please input the right command.\n");
break;
default:
printf("Please input the right command.\n");
break;
}
}
}
return 0;
}