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filesys.c
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#include<stdio.h>
#include<malloc.h>
#include<time.h>
#include<stdlib.h>
#include<string.h>
#define BLOCKSIZE 1024
#define SIZE 1024000
#define END 65535
#define FREE 0
#define ROOT_BLOCKNUM 2
#define MAX_OPEN_FILE 10
#define MAX_TXT_SIZE 10000
typedef struct FCB
{
char filename[8]; /*8B文件名*/
char exname[3]; /*3B扩展名*/
unsigned char attribute; /*文件属性字段*/
char retainbyte[10] ; /*10B保留字*/
unsigned short time; /*文件创建时间*/
unsigned short date; /*文件创建日期*/
unsigned short first; /*首块号*/
unsigned long length; /*文件大小*/
}fcb;
/*
文件分配表 file allocation table
*/
typedef struct FAT
{
unsigned short id;
}fat;
/*
属性对照表
位 7 6 5 4 3 2 1 0
属性 保留 保留 存档 子目录 卷标 系统文件 隐藏 只读
*/
typedef struct USEROPEN
{
char filename[8]; /*8B文件名*/
char exname[3]; /*3B扩展名*/
unsigned char attribute; /*文件属性字段*/
char retainbyte[10] ; /*10B保留字*/
unsigned short time; /*文件创建时间*/
unsigned short date; /*文件创建日期*/
unsigned short first; /*首块号*/
unsigned long length; /*文件大小*/
char free; /*表示目录项是否为空 0空1分配*/
int father; /*父目录的文件描述符*/
int dirno; /*相应打开文件的目录项在父目录文件中的盘块号*/
int diroff; /*相应打开文件的目录项在父目录文件的dirno盘块中的目录项序号*/
char dir[MAX_OPEN_FILE][80]; /*相应打开文件所在的目录*/
int count; /*读写指针在文件中的位置*/
char fcbstate; /*是否修改了文件的FCB内容，修改置1，否则为0*/
char topenfile; /*表示该用户打开的表项是否为空，若值为0，表示为空*/
}useropen;
typedef struct BLOCK0
{
unsigned short fbnum;
char information[200];
unsigned short root;
unsigned char *startblock;
}block0;
/*全局变量定义*/
unsigned char *myvhard; /*指向虚拟磁盘的起始地址*/
useropen openfilelist[MAX_OPEN_FILE]; /*用户打开文件表数组*/
useropen *ptrcurdir; /*指向用户打开文件表中的当前目录所在打开文件表项的位置*/
int curfd;
char currentdir[80]; /*记录当前目录的文件名*/
unsigned char *startp; /*记录虚拟磁盘上数据区开始位置*/
char filename[]="c:\\myfilesys"; /*虚拟空间保存路径*/
unsigned char buffer[SIZE];
/*函数声明*/
void startsys();
void my_format();
void my_cd(char *dirname);
void my_mkdir(char *dirname);
void my_rmdir(char *dirname);
void my_ls();
void my_create(char *filename);
void my_rm(char *filename);
int my_open(char *filename);
int my_close(int fd);
int my_write(int fd);
int do_write(int fd,char *text,int len,char wstyle);
unsigned short findFree();
int my_read(int fd,int len);
int do_read(int fd,int len,char *text);
void my_exitsys();
/*函数设计*/
/*文件系统初始化*/
/*
原型声明: void startsys()
功能描述： 文件系统初始化,初始化所建立的文件系统
输入：无
输出：无
函数功能实现算法描述：
1）申请磁盘空间
2）打开系统磁盘，若不存在，创建新的系统磁盘，并格式化
3）初始化用户打开文件表，将表项0分配给根目录文件使用
并填写根目录文件的相关信息
4）将ptrcurdir指向该用户打开文件表项
5）将当前目录设置为根目录
*/
void startsys()
{
FILE *fp;
int i;
myvhard=(unsigned char *)malloc(SIZE);
memset(myvhard,0,SIZE);
fp=fopen(filename,"r");
if(fp)
{
fread(buffer,SIZE,1,fp);
fclose(fp);
if(buffer[0]!=0xaa||buffer[1]!=0xaa)
{
printf("myfilesys is not exist,begin to creat the file...\n");
my_format();
}
else
{
for(i=0;i<SIZE;i++)
myvhard[i]=buffer[i];
}
}
else
{
printf("myfilesys is not exist,begin to creat the file...\n");
my_format();
}
strcpy(openfilelist[0].filename,"root");
strcpy(openfilelist[0].exname,"di");
openfilelist[0].attribute=0x2d;
openfilelist[0].time=((fcb *)(myvhard+5*BLOCKSIZE))->time;
openfilelist[0].date=((fcb *)(myvhard+5*BLOCKSIZE))->date;
openfilelist[0].first=((fcb *)(myvhard+5*BLOCKSIZE))->first;
openfilelist[0].length=((fcb *)(myvhard+5*BLOCKSIZE))->length;
openfilelist[0].free=1;
openfilelist[0].dirno=5;
openfilelist[0].diroff=0;
openfilelist[0].count=0;
openfilelist[0].fcbstate=0;
openfilelist[0].topenfile=0;
openfilelist[0].father=0;
memset(currentdir,0,sizeof(currentdir));
strcpy(currentdir,"\\root\\");
strcpy(openfilelist->dir[0],currentdir);
startp=((block0 *)myvhard)->startblock;
ptrcurdir=&openfilelist[0];
curfd=0;
}
/*
原型声明: void my_format()
功能描述： 对虚拟磁盘进行格式化，布局虚拟磁盘，建立根目录文件
输入：无
输出：无
函数功能实现算法描述：
虚拟磁盘空间布局
1块 2块 2块 995块
引导块 FAT1 FAT2 数据区
虚拟磁盘一共划分成1000个磁盘块
每块1024个字节，磁盘空间布局如上
将数据区的第一块（即虚拟磁盘的第6块）分配给根目录文件
*/
void my_format()
{
FILE *fp;
fat *fat1,*fat2;
block0 *b0;
time_t *now;
struct tm *nowtime;
unsigned char *p;
fcb *root;
int i;
p=myvhard;
b0=(block0 *)p;
fat1=(fat *)(p+BLOCKSIZE);
fat2=(fat*)(p+3*BLOCKSIZE);
/*
引导块
*/
b0->fbnum=0xaaaa; /*文件系统魔数 10101010*/
b0->root = 5;
strcpy(b0->information,"My FileSystem Ver 1.0 \n Blocksize=1KB Whole size=1000KB Blocknum=1000 RootBlocknum=2\n");
/*
FAT1,FAT2
前面五个磁盘块已分配，标记为END
*/
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
fat1->id=6;
fat2->id=6;
fat1++;fat2++;
fat1->id=END;
fat2->id=END;
fat1++;fat2++;
/*
将数据区的标记为空闲状态
*/
for(i=7;i<SIZE/BLOCKSIZE;i++)
{
(*fat1).id=FREE;
(*fat2).id=FREE;
fat1++;
fat2++;
}
/*
创建根目录文件root，将数据区的第一块分配给根目录区
在给磁盘上创建两个特殊的目录项：".",".."，
除了文件名之外，其它都相同
*/
p+=BLOCKSIZE*5;
root=(fcb *)p;
strcpy(root->filename,".");
strcpy(root->exname,"di");
root->attribute=40;
now=(time_t *)malloc(sizeof(time_t));
time(now);
nowtime=localtime(now);
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++;
strcpy(root->filename,"..");
strcpy(root->exname,"di");
root->attribute=40;
time(now);
nowtime=localtime(now);
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++;
for(i=2;i<BLOCKSIZE*2/sizeof(fcb);i++,root++)
{
root->filename[0]='\0';
}
fp=fopen(filename,"w");
b0->startblock=p+BLOCKSIZE*4;
fwrite(myvhard,SIZE,1,fp);
free(now);
fclose(fp);
}
/**/
/*
原型声明: void my_exitsys()
功能描述： 退出文件系统
输入： 无
输出： 无
函数功能实现算法描述：
*/
void my_exitsys()
{
FILE *fp;
fcb *rootfcb;
char text[MAX_TXT_SIZE];
while(curfd)
curfd=my_close(curfd);
if(openfilelist[curfd].fcbstate)
{
openfilelist[curfd].count=0;
do_read(curfd,openfilelist[curfd].length,text);
rootfcb=(char *)text;
rootfcb->length=openfilelist[curfd].length;
openfilelist[curfd].count=0;
do_write(curfd,text,openfilelist[curfd].length,2);
}
fp=fopen(filename,"w");
fwrite(myvhard,SIZE,1,fp);
free(myvhard);
fclose(fp);
}
/*
原型声明: int do_read(int fd,int len,char *text)
功能描述： 实际读文件函数，读出指定文件中从指定指针开始的长度
为len的内容到用户空间的text中
输入：
fd open（）函数的返回值，文件的描述符
len 要求从文件中读出的字节数
text 指向存放读出数据的用户区地址
输出：
实际读出的字节数
函数功能实现算法描述：
*/
int do_read(int fd,int len,char *text)
{
unsigned char *buf;
unsigned short bknum;
int off,i,lentmp;
unsigned char *bkptr;
char *txtmp,*p;
fat *fat1,*fatptr;
fat1=(fat *)(myvhard+BLOCKSIZE);
lentmp = len;
txtmp=text;
/*
申请1024B空间作为缓冲区buffer
*/
buf=(unsigned char *)malloc(1024);
if(buf==NULL)
{
printf("malloc failed!\n");
return -1;
}
off = openfilelist[fd].count;
bknum = openfilelist[fd].first;
fatptr = fat1+bknum;
while(off >= BLOCKSIZE)
{
off=off-BLOCKSIZE;
bknum=fatptr->id;
fatptr=fat1+bknum;
if(bknum == END)
{
printf("Error,the block is not exist.\n");
return -1;
}
}
bkptr=(unsigned char *)(myvhard+bknum*BLOCKSIZE);
//strncpy(buf,bkptr,BLOCKSIZE);
for(i=0;i<BLOCKSIZE;i++)
{
buf[i]=bkptr[i];
}
while(len > 0)
{
if(BLOCKSIZE-off > len)
{
//strncpy(txtmp,buf+off,len);
//len=len-len;
//openfilelist[fd].count+=len;
//off+=len;
for(p=buf+off;len>0;p++,txtmp++)
{
*txtmp=*p;
len--;
off++;
openfilelist[fd].count++;
}
}
else
{
//strncpy(txtmp,buf+off,BLOCKSIZE-off);
//len=len-(BLOCKSIZE-off);
//openfilelist[fd].count+=(BLOCKSIZE-off);
for(p=buf+off;p<buf+BLOCKSIZE;p++,txtmp++)
{
*txtmp=*p;
len--;
openfilelist[fd].count++;
}
off=0;
//txtmp+=(BLOCKSIZE-off);
bknum =fatptr->id;
fatptr = fat1+bknum;
bkptr=(unsigned char *)(myvhard+bknum*BLOCKSIZE);
//strncpy(buf,bkptr,BLOCKSIZE);
for(i=0;i<BLOCKSIZE;i++)
{
buf[i]=bkptr[i];
}
}
}
free(buf);
return lentmp-len;
}
/**/
/*
原型声明: int my_read(int fd,int len)
功能描述： 读文件函数
输入：
fd 打开文件的id
len 要读出字符的个数
输出： 返回实际读的字符的个数
函数功能实现算法描述：
*/
int my_read(int fd,int len)
{
char text[MAX_TXT_SIZE];
if(fd > MAX_OPEN_FILE)
{
printf("The File is not exist!\n");
return -1;
}
openfilelist[curfd].count=0;
if(do_read(fd,len,text)>0)
{
text[len]='\0';
printf("%s\n",text);
}
else
{
printf("Read Error!\n");
return -1;
}
return len;
}
/**/
/*
原型声明: int do_write(int fd,char *text,int len,char wstyle)
功能描述： 实际写文件函数
输入：
fd 当前打开的文件的id
text 指向要写入的内容的指针
len 本次要写入字节数
wstyle 写方式
输出： 实际写入的字节数
函数功能实现算法描述：
*/
int do_write(int fd,char *text,int len,char wstyle)
{
unsigned char *buf;
unsigned short bknum;
int off,tmplen=0,tmplen2=0,i,rwptr;
unsigned char *bkptr,*p;
char *txtmp,flag=0;
fat *fat1,*fatptr;
fat1=(fat *)(myvhard+BLOCKSIZE);
txtmp=text;
/*
申请临时1024B的buffer
*/
buf=(unsigned char *)malloc(BLOCKSIZE);
if(buf==NULL)
{
printf("malloc failed!\n");
return -1;
}
rwptr = off = openfilelist[fd].count;
bknum = openfilelist[fd].first;
fatptr=fat1+bknum;
while(off >= BLOCKSIZE )
{
off=off-BLOCKSIZE;
bknum=fatptr->id;
if(bknum == END)
{
bknum=fatptr->id=findFree();
if(bknum==END) return -1;
fatptr=fat1+bknum;
fatptr->id=END;
}
fatptr=fat1+bknum;
}
fatptr->id=END;
bkptr=(unsigned char *)(myvhard+bknum*BLOCKSIZE);
while(tmplen<len)
{
for(i=0;i<BLOCKSIZE;i++)
{
buf[i]=0;
}
//if(off)
//{
for(i=0;i<BLOCKSIZE;i++)
{
buf[i]=bkptr[i];
tmplen2++;
if(tmplen2==openfilelist[curfd].length)
break;
}
//}
//else
//{
//for(i=0;i<BLOCKSIZE;i++)
//{
// buf[i]=0;
//}
//}
for(p=buf+off;p<buf+BLOCKSIZE;p++)
{
*p=*txtmp;
tmplen++;
txtmp++;
off++;
if(tmplen==len)
break;
/*if((*p)==NULL)
{
break;
}*/
}
for(i=0;i<BLOCKSIZE;i++)
{
bkptr[i]=buf[i];
}
openfilelist[fd].count=rwptr+tmplen;
if(off>=BLOCKSIZE)
{
off=off-BLOCKSIZE;
bknum=fatptr->id;
if(bknum==END)
{
bknum=fatptr->id=findFree();
if(bknum==END) return -1;
fatptr=fat1+bknum;
fatptr->id=END;
}
fatptr=fat1+bknum;
bkptr=(unsigned char *)(myvhard+bknum*BLOCKSIZE);
}
}
free(buf);
if(openfilelist[fd].count>openfilelist[fd].length)
{
openfilelist[fd].length=openfilelist[fd].count;
}
openfilelist[fd].fcbstate=1;
return tmplen;
}
/**/
/*
原型声明: unsigned short findFree()
功能描述： 寻找下一个空闲盘块
输入： 无
输出： 返回空闲盘块的id
函数功能实现算法描述：
*/
unsigned short findFree()
{
unsigned short i;
fat *fat1,*fatptr;
fat1=(fat *)(myvhard+BLOCKSIZE);
for(i=6; i<END; i++)
{
fatptr=fat1+i;
if(fatptr->id == FREE)
{
return i;
}
}
printf("Error,Can't find free block!\n");
return END;
}
/*
原型声明: int findFreeO()
功能描述： 寻找空闲文件表项
输入： 无
输出： 返回空闲文件表项的id
函数功能实现算法描述：
*/
int findFreeO()
{
int i;
for(i=0;i<MAX_OPEN_FILE;i++)
{
if(openfilelist[i].free==0)
{
return i;
}
}
printf("Error,open too many files!\n");
return -1;
}
/**/
/*
原型声明: int my_write(int fd)
功能描述： 写文件函数
输入：
fd 打开文件的id
输出： 返回实际写的长度
函数功能实现算法描述：
*/
int my_write(int fd)
{
int wstyle=0,wlen=0;
fat *fat1,*fatptr;
unsigned short bknum;
unsigned char *bkptr;
char text[MAX_TXT_SIZE];
fat1=(fat *)(myvhard+BLOCKSIZE);
if(fd>MAX_OPEN_FILE)
{
printf("The file is not exist!\n");
return -1;
}
while(wstyle<1||wstyle>3)
{
printf("Please enter the number of write style:\n1.cut write\t2.cover write\t3.add write\n");
scanf("%d",&wstyle);
getchar();
switch(wstyle)
{
case 1://截断写
{
bknum=openfilelist[fd].first;
fatptr=fat1+bknum;
while(fatptr->id!=END)
{
bknum=fatptr->id;
fatptr->id=FREE;
fatptr=fat1+bknum;
}
fatptr->id=FREE;
bknum=openfilelist[fd].first;
fatptr=fat1+bknum;
fatptr->id=END;
openfilelist[fd].length=0;
openfilelist[fd].count=0;
break;
}
case 2://覆盖写
{
openfilelist[fd].count=0;
break;
}
case 3://追加写
{
bknum=openfilelist[fd].first;
fatptr=fat1+bknum;
openfilelist[fd].count=0;
while(fatptr->id!=END)
{
bknum=fatptr->id;
fatptr=fat1+bknum;
openfilelist[fd].count+=BLOCKSIZE;
}
bkptr=(unsigned char *)(myvhard+bknum*BLOCKSIZE);
while(*bkptr !=0)
{
bkptr++;
openfilelist[fd].count++;
}
break;
}
default:
break;
}
}
printf("please input write data:\n");
gets(text);
if(do_write(fd,text,strlen(text),wstyle)>0)
{
wlen+=strlen(text);
}
else
{
return -1;
}
if(openfilelist[fd].count>openfilelist[fd].length)
{
openfilelist[fd].length=openfilelist[fd].count;
}
openfilelist[fd].fcbstate=1;
return wlen;
}
/*
原型声明: void my_mkdir(char *dirname)
功能描述： 创建子目录函数,在当前目录下创建名为dirname的目录
输入：
dirname 指向新建目录的名字的指针
输出：无
函数功能实现算法描述：
*/
void my_mkdir(char *dirname)
{
fcb *dirfcb,*pcbtmp;
int rbn,i,fd;
unsigned short bknum;
char text[MAX_TXT_SIZE],*p;
time_t *now;
struct tm *nowtime;
/*
将当前的文件信息读到text中
rbn 是实际读取的字节数
*/
openfilelist[curfd].count=0;
rbn = do_read(curfd,openfilelist[curfd].length,text);
dirfcb=(fcb *)text;
/*
检测是否有相同的目录名
*/
for(i=0;i<rbn/sizeof(fcb);i++)
{
if(strcmp(dirname,dirfcb->filename)==0)
{
printf("Error,the dirname is already exist!\n");
return -1;
}
dirfcb++;
}
/*
分配一个空闲的打开文件表项
*/
dirfcb=(fcb *)text;
for(i=0;i<rbn/sizeof(fcb);i++)
{
if(strcmp(dirfcb->filename,"")==0)
break;
dirfcb++;
}
openfilelist[curfd].count=i*sizeof(fcb);
fd=findFreeO();
if(fd<0)
{
return -1;
}
/*
寻找空闲盘块
*/
bknum = findFree();
if(bknum == END )
{
return -1;
}
pcbtmp=(fcb *)malloc(sizeof(fcb));
now=(time_t *)malloc(sizeof(time_t));
//在当前目录下新建目录项
pcbtmp->attribute=0x30;
time(now);
nowtime=localtime(now);
pcbtmp->time=nowtime->tm_hour*2048+nowtime->tm_min*32+nowtime->tm_sec/2;
pcbtmp->date=(nowtime->tm_year-80)*512+(nowtime->tm_mon+1)*32+nowtime->tm_mday;
strcpy(pcbtmp->filename,dirname);
strcpy(pcbtmp->exname,"di");
pcbtmp->first=bknum;
pcbtmp->length=2*sizeof(fcb);
openfilelist[fd].attribute=pcbtmp->attribute;
openfilelist[fd].count=0;
openfilelist[fd].date=pcbtmp->date;
strcpy(openfilelist[fd].dir[fd],openfilelist[curfd].dir[curfd]);
p=openfilelist[fd].dir[fd];
while(*p!='\0')
p++;
strcpy(p,dirname);
while(*p!='\0') p++;
*p='\\';p++;
*p='\0';
openfilelist[fd].dirno=openfilelist[curfd].first;
openfilelist[fd].diroff=i;
strcpy(openfilelist[fd].exname,pcbtmp->exname);
strcpy(openfilelist[fd].filename,pcbtmp->filename);
openfilelist[fd].fcbstate=1;
openfilelist[fd].first=pcbtmp->first;
openfilelist[fd].length=pcbtmp->length;
openfilelist[fd].free=1;
openfilelist[fd].time=pcbtmp->time;
openfilelist[fd].topenfile=1;
do_write(curfd,(char *)pcbtmp,sizeof(fcb),2);
pcbtmp->attribute=0x28;
time(now);
nowtime=localtime(now);
pcbtmp->time=nowtime->tm_hour*2048+nowtime->tm_min*32+nowtime->tm_sec/2;
pcbtmp->date=(nowtime->tm_year-80)*512+(nowtime->tm_mon+1)*32+nowtime->tm_mday;
strcpy(pcbtmp->filename,".");
strcpy(pcbtmp->exname,"di");
pcbtmp->first=bknum;
pcbtmp->length=2*sizeof(fcb);
do_write(fd,(char *)pcbtmp,sizeof(fcb),2);
pcbtmp->attribute=0x28;
time(now);
nowtime=localtime(now);
pcbtmp->time=nowtime->tm_hour*2048+nowtime->tm_min*32+nowtime->tm_sec/2;
pcbtmp->date=(nowtime->tm_year-80)*512+(nowtime->tm_mon+1)*32+nowtime->tm_mday;
strcpy(pcbtmp->filename,"..");
strcpy(pcbtmp->exname,"di");
pcbtmp->first=openfilelist[curfd].first;
pcbtmp->length=openfilelist[curfd].length;
do_write(fd,(char *)pcbtmp,sizeof(fcb),2);
openfilelist[curfd].count=0;
do_read(curfd,openfilelist[curfd].length,text);
pcbtmp=(fcb *)text;
pcbtmp->length=openfilelist[curfd].length;
my_close(fd);
openfilelist[curfd].count=0;
do_write(curfd,text,pcbtmp->length,2);
}
/**/
/*
原型声明: void my_ls()
功能描述： 显示目录函数
输入： 无
输出： 无
函数功能实现算法描述：
*/
void my_ls()
{
fcb *fcbptr;
int i;
char text[MAX_TXT_SIZE];
unsigned short bknum;
openfilelist[curfd].count=0;
do_read(curfd,openfilelist[curfd].length,text);
fcbptr=(fcb *)text;
for(i=0;i<(int)(openfilelist[curfd].length/sizeof(fcb));i++)
{
if(fcbptr->filename[0]!='\0')
{
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,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++;
}
openfilelist[curfd].count=0;
}
/**/
/*
原型声明: void my_rmdir(char *dirname)
功能描述： 删除子目录函数
输入：
dirname 指向新建目录的名字的指针
输出：无
函数功能实现算法描述：
*/
void my_rmdir(char *dirname)
{
int rbn,fd;
char text[MAX_TXT_SIZE];
fcb *fcbptr,*fcbtmp,*fcbtmp2;
unsigned short bknum;
int i,j;
fat *fat1,*fatptr;
if(strcmp(dirname,".")==0 || strcmp(dirname,"..")==0)
{
printf("Error,can't remove this directory.\n");
return -1;
}
fat1=(fat *)(myvhard+BLOCKSIZE);
openfilelist[curfd].count=0;
rbn=do_read(curfd,openfilelist[curfd].length,text);
fcbptr=(fcb *)text;
for(i=0;i<rbn/sizeof(fcb);i++)
{
if(strcmp(dirname,fcbptr->filename)==0)
{
break;
}
fcbptr++;
}
if(i >= rbn/sizeof(fcb))
{
printf("Error,the directory is not exist.\n");
return -1;
}
bknum=fcbptr->first;
fcbtmp2=fcbtmp=(fcb *)(myvhard+bknum*BLOCKSIZE);
for(j=0;j<fcbtmp->length/sizeof(fcb);j++)
{
if(strcmp(fcbtmp2->filename,".") && strcmp(fcbtmp2->filename,"..") && fcbtmp2->filename[0]!='\0')
{
printf("Error,the directory is not empty.\n");
return -1;
}
fcbtmp2++;
}
while(bknum!=END)
{
fatptr=fat1+bknum;
bknum=fatptr->id;
fatptr->id=FREE;
}
strcpy(fcbptr->filename,"");
strcpy(fcbptr->exname,"");
fcbptr->first=END;
openfilelist[curfd].count=0;
do_write(curfd,text,openfilelist[curfd].length,2);
}
/*
原型声明: int my_open(char *filename)
功能描述： 打开文件函数
输入：
filename 指向要打开的文件的名字的指针
输出： 返回打开的文件的id
函数功能实现算法描述：
*/
int my_open(char *filename)
{
int i,fd,rbn;
char text[MAX_TXT_SIZE],*p,*fname,*exname;
fcb *fcbptr;
char exnamed=0;
fname=strtok(filename,".");
exname=strtok(NULL,".");
if(!exname)
{
exname=(char *)malloc(3);
strcpy(exname,"di");
exnamed=1;
}
for(i=0;i<MAX_OPEN_FILE;i++)
{
if(strcmp(openfilelist[i].filename,filename)==0 &&strcmp(openfilelist[i].exname,exname)==0&& i!=curfd)
{
printf("Error,the file is already open.\n");
return -1;
}
}
openfilelist[curfd].count=0;
rbn=do_read(curfd,openfilelist[curfd].length,text);
fcbptr=(fcb *)text;
for(i=0;i<rbn/sizeof(fcb);i++)