操作系统磁盘文件管理源码

1、#include<stdio.h> #include<string.h> #include<stdlib.h> #define MEM_D_SIZE 1024*1024 /总磁盘空间为1M#define DISKSIZE 1024/磁盘块的大小1K#define DISK_NUM 1024/磁盘块数目1K#define FATSIZE DISK_NUM*sizeof(struct fatitem)/FAT表大小#define ROOT_DISK_NO FATSIZE/DISKSIZE+1/根目录起始盘块号#define ROOT_DISK_SIZE size

2、of(struct direct)/根目录大小#define DIR_MAXSIZE 1024/路径最大长度为1KB#define MSD 5/最大子目录数5#define MOFN 5/最大文件深度为5#define MAX_WRITE 1024*128/最大写入文字长度128KB struct fatitem /* size 8*/ int item; /*存放文件下一个磁盘的指针*/ char em_disk; /*磁盘块是否空闲标志位 0 空闲*/ ; struct direct /*-文件控制快信息-*/ struct FCB char name9; /*文件/目录名 8位*/ ch

3、ar property; /*属性 1位目录 0位普通文件*/ int size; /*文件/目录字节数、盘块数)*/ int firstdisk; /*文件/目录 起始盘块号*/ int next; /*子目录起始盘块号*/ int sign; /*1是根目录 0不是根目录*/ directitemMSD+2; ; struct opentable struct openttableitem char name9; /*文件名*/ int firstdisk; /*起始盘块号*/ int size; /*文件的大小*/ openitemMOFN; int cur_size; /*当前打文件的

4、数目*/ ; struct fatitem *fat; /*FAT表*/ struct direct *root; /*根目录*/ struct direct *cur_dir; /*当前目录*/ struct opentable u_opentable; /*文件打开表*/ int fd=-1; /*文件打开表的序号*/ char *bufferdir; /*记录当前路径的名称*/ char *fdisk; /*虚拟磁盘起始地址*/ void initfile(); void format(); void enter(); void halt(); int create(char *name

5、); int open(char *name); int close(char *name); int write(int fd,char *buf,int len); int read(int fd,char *buf); int del(char *name); int mkdir(char *name); int rmdir(char *name); void dir(); int cd(char *name); void print(); void show(); void initfile() fdisk = (char *)malloc(MEM_D_SIZE*sizeof(char

6、); /*申请 1M空间*/ format(); void format() int i; FILE *fp; fat = (struct fatitem *)(fdisk+DISKSIZE); /*计算FAT表地址，引导区向后偏移 1k)*/ /*-初始化FAT表-*/ fat0.item=-1; /*引导块*/ fat0.em_disk='1' for(i=1;i<ROOT_DISK_NO-1;i+) /*存放 FAT表的磁盘块号*/ fati.item=i+1; fati.em_disk='1' fatROOT_DISK_NO.item=-1; /*

7、存放根目录的磁盘块号*/ fatROOT_DISK_NO.em_disk='1' for(i=ROOT_DISK_NO+1;i<DISK_NUM;i+) fati.item = -1; fati.em_disk = '0' /*-*/ root = (struct direct *)(fdisk+DISKSIZE+FATSIZE); /*根目录的地址*/ /*初始化目录*/ /*-指向当前目录的目录项-*/ root->directitem0.sign = 1; root->directitem0.firstdisk = ROOT_DISK_N

8、O; strcpy(root->,"."); root->directitem0.next = root->directitem0.firstdisk; root->perty = '1' root->directitem0.size = ROOT_DISK_SIZE; /*-指向上一级目录的目录项-*/ root->directitem1.sign = 1; root->directitem1.firstdisk = ROOT_DISK_NO; strc

9、py(root->,"."); root->directitem1.next = root->directitem0.firstdisk; root->perty = '1' root->directitem1.size = ROOT_DISK_SIZE; if(fp = fopen("disk.dat","wb")=NULL) printf("Error:n Cannot open file n"); re

10、turn; for(i=2;i<MSD+2;i+) /*-子目录初始化为空-*/ root->directitemi.sign = 0; root->directitemi.firstdisk = -1; strcpy(root->,""); root->directitemi.next = -1; root->perty = '0' root->directitemi.size = 0; if(fp = fopen("disk.dat"

11、;,"wb")=NULL) printf("Error:n Cannot open file n"); return; if(fwrite(fdisk,MEM_D_SIZE,1,fp)!=1) /*把虚拟磁盘空间保存到磁盘文件中*/ printf("Error:n File write error! n"); fclose(fp); void enter() FILE *fp; int i; fdisk = (char *)malloc(MEM_D_SIZE*sizeof(char); /*申请 1M空间*/ if(fp=fopen(

12、"disk.dat","rb")=NULL) printf("Error:nCannot open filen"); return; if(!fread(fdisk,MEM_D_SIZE,1,fp) /*把磁盘文件disk.dat 读入虚拟磁盘空间(内存)*/ printf("Error:nCannot read filen"); exit(0); fat = (struct fatitem *)(fdisk+DISKSIZE); /*找到FAT表地址*/ root = (struct direct *)(fdis

13、k+DISKSIZE+FATSIZE);/*找到根目录地址*/ fclose(fp); /*-初始化用户打开表-*/ for(i=0;i<MOFN;i+) strcpy(u_,""); u_opentable.openitemi.firstdisk = -1; u_opentable.openitemi.size = 0; u_opentable.cur_size = 0; cur_dir = root; /*当前目录为根目录*/ bufferdir = (char *)malloc(DIR_MAXSIZE*sizeof

14、(char); strcpy(bufferdir,"Root:"); void halt() FILE *fp; int i; if(fp=fopen("disk.dat","wb")=NULL) printf("Error:nCannot open filen"); return; if(!fwrite(fdisk,MEM_D_SIZE,1,fp) /*把虚拟磁盘空间(内存)内容读入磁盘文件disk.dat */ printf("Error:nFile write error!n"); fcl

15、ose(fp); free(fdisk); free(bufferdir); return;int create(char *name) int i,j; if(strlen(name)>8) /*文件名大于 8位*/ return(-1); for(j=2;j<MSD+2;j+) /*检查创建文件是否与已存在的文件重名*/ if(!strcmp(cur_dir->,name) break; if(j<MSD+2) /*文件已经存在*/ return(-4); for(i=2;i<MSD+2;i+) /*找到第一个空闲子目录*/ i

16、f(cur_dir->directitemi.firstdisk=-1) break; if(i>=MSD+2) /*无空目录项*/ return(-2); if(u_opentable.cur_size>=MOFN) /*打开文件太多*/ return(-3); for(j=ROOT_DISK_NO+1;j<DISK_NUM;j+) /*找到空闲盘块 j 后退出*/ if(fatj.em_disk='0') break; if(j>=DISK_NUM) return(-5); fatj.em_disk = '1' /*将空闲块置为

17、已经分配*/ /*-填写目录项-*/ strcpy(cur_dir->,name); cur_dir->directitemi.firstdisk = j; cur_dir->directitemi.size = 0; cur_dir->directitemi.next = j; cur_dir->perty = '0' /*-*/ fd = open(name); return 0; int open(char *name) int i, j; for(i=2;i<MSD+2;i

18、+) /*文件是否存在*/ if(!strcmp(cur_dir->,name) break; if(i>=MSD+2) return(-1); /*-是文件还是目录-*/ if(cur_dir->perty='1')return(-4); /*-文件是否打开-*/ for(j=0;j<MOFN;j+) if(!strcmp(u_,name) break; if(j<MOFN) /*文件已经打开*/ return(-2); if(u_ope

19、ntable.cur_size>=MOFN) /*文件打开太多*/ return(-3); /*-查找一个空闲用户打开表项-*/ for(j=0;j<MOFN;j+) if(u_opentable.openitemj.firstdisk=-1) break; /*-填写表项的相关信息-*/ u_opentable.openitemj.firstdisk = cur_dir->directitemi.firstdisk; strcpy(u_,name); u_opentable.openitemj.size = cur_dir-&

20、gt;directitemi.size; u_opentable.cur_size+; /*-返回用户打开表表项的序号-*/ return(j); int close(char *name) int i; for(i=0;i<MOFN;i+) if(!strcmp(u_,name) break; if(i>=MOFN) return(-1); /*-清空该文件的用户打开表项的内容-*/ strcpy(u_,""); u_opentable.openitemi.firs

21、tdisk = -1; u_opentable.openitemi.size = 0; u_opentable.cur_size-; return 0; int write(int fd, char *buf, int len) char *first; int item, i, j, k; int ilen1, ilen2, modlen, temp; /*-用 $ 字符作为空格 # 字符作为换行符-*/ char Space = 32; char Endter= 'n' for(i=0;i<len;i+) if(bufi = '$') bufi = S

22、pace; else if(bufi = '#') bufi = Endter; /*-读取用户打开表对应表项第一个盘块号-*/ item = u_opentable.openitemfd.firstdisk; /*-找到当前目录所对应表项的序号-*/ for(i=2;i<MSD+2;i+) if(cur_dir->directitemi.firstdisk=item) break; temp = i; /*-存放当前目录项的下标-*/ /*-找到的item 是该文件的最后一块磁盘块-*/ while(fatitem.item!=-1) item =fatitem.

23、item; /*-查找该文件的下一盘块-*/ /*-计算出该文件的最末地址-*/ first = fdisk+item*DISKSIZE+u_opentable.openitemfd.size%DISKSIZE; /*-如果最后磁盘块剩余的大小大于要写入的文件的大小-*/ if(DISKSIZE-u_opentable.openitemfd.size%DISKSIZE>len) strcpy(first,buf); u_opentable.openitemfd.size = u_opentable.openitemfd.size+len; cur_dir->directitemte

24、mp.size = cur_dir->directitemtemp.size+len; else for(i=0;i<(DISKSIZE-u_opentable.openitemfd.size%DISKSIZE);i+) /*写一部分内容到最后一块磁盘块的剩余空间(字节)*/ firsti = buf i; /*-计算分配完最后一块磁盘的剩余空间(字节) 还剩下多少字节未存储-*/ ilen1 = len-(DISKSIZE-u_opentable.openitemfd.size%DISKSIZE); ilen2 = ilen1/DISKSIZE; modlen = ilen1%D

25、ISKSIZE; if(modlen>0) ilen2 = ilen2+1; /*-还需要多少块磁盘块-*/ for(j=0;j<ilen2;j+) for(i=ROOT_DISK_NO+1;i<DISK_NUM;i+)/*寻找空闲磁盘块*/ if(fati.em_disk='0') break; if(i>=DISK_NUM) /*-如果磁盘块已经分配完了-*/ return(-1); first = fdisk+i*DISKSIZE; /*-找到的那块空闲磁盘块的起始地址-*/ if(j=ilen2-1) /*-如果是最后要分配的一块-*/ for(

26、k=0;k<len-(DISKSIZE-u_opentable.openitemfd.size%DISKSIZE)-j*DISKSIZE;k+) firstk = bufk; else/*-如果不是要最后分配的一块-*/ for(k=0;k<DISKSIZE;k+) firstk =bufk; fatitem.item = i; /*-找到一块后将它的序号存放在上一块的指针中-*/ fati.em_disk = '1' /*-置找到的磁盘快的空闲标志位为已分配-*/ fati.item = -1; /*-它的指针为 -1 (即没有下一块)-*/ /*-修改长度-*/

27、 u_opentable.openitemfd.size = u_opentable.openitemfd.size+len; cur_dir->directitemtemp.size = cur_dir->directitemtemp.size+len; return 0; int read(int fd, char *buf) int len = u_opentable.openitemfd.size; char *first; int i, j, item; int ilen1, modlen; item = u_opentable.openitemfd.firstdisk;

28、 ilen1 = len/DISKSIZE; modlen = len%DISKSIZE; if(modlen!=0) ilen1 = ilen1+1; /*-计算文件所占磁盘的块数-*/ first = fdisk+item*DISKSIZE; /*-计算文件的起始位置-*/ for(i=0;i<ilen1;i+) if(i=ilen1-1) /*-如果在最后一个磁盘块-*/ for(j=0;j<len-i*DISKSIZE;j+) bufi*DISKSIZE+j = firstj; else /*-不在最后一块磁盘块-*/ for(j=0;j<len-i*DISKSIZE

29、;j+) bufi*DISKSIZE+j = firstj; item = fatitem.item; /*-查找下一盘块-*/ first = fdisk+item*DISKSIZE; return 0; int del(char *name) int i,cur_item,item,temp; for(i=2;i<MSD+2;i+) /*-查找要删除文件是否在当前目录中-*/ if(!strcmp(cur_dir->,name) break; cur_item = i; /*-用来保存目录项的序号,供释放目录中-*/ if(i>=MSD+2

30、) /*-如果不在当前目录中-*/ return(-1); if(cur_dir->directitemcur_perty!='0') /*-如果删除的(不)是目录-*/ return(-3); for(i=0;i<MOFN;i+) /*-如果文件打开,则不能删除,退出-*/ if(!strcmp(u_,name) return(-2); item = cur_dir->directitemcur_item.firstdisk;/*-该文件的起始盘块号-*/ while(item!=-1) /*-

31、释放空间,将FAT表对应项进行修改-*/ temp = fatitem.item; fatitem.item = -1; fatitem.em_disk = '0' item = temp; /*-释放目录项-*/ cur_dir->directitemcur_item.sign = 0; cur_dir->directitemcur_item.firstdisk = -1; strcpy(u_opentable.openitemcur_,""); cur_dir->directitemcur_item.next = -1

32、; cur_dir->directitemcur_perty = '0' cur_dir->directitemcur_item.size = 0; return 0; int mkdir(char *name) int i,j; struct direct *cur_mkdir; if(!strcmp(name,".") return(-4); if(!strcmp(name,".") return(-4); if(strlen(name)>8) /*-如果目录名长度大于 8位-*/ return(-1

33、); for(i=2;i<MSD+2;i+) /*-如果有空闲目录项退出-*/ if(cur_dir->directitemi.firstdisk=-1) break; if(i>=MSD+2) /*-目录/文件 已满-*/ return(-2); for(j=2;j<MSD+2;j+) /*-判断是否有重名-*/ if(!strcmp(cur_dir->,name) break; if(j<MSD+2) /*-如果有重名-*/ return(-3); for(j=ROOT_DISK_NO+1;j<DISK_NUM;j+

34、) /*-找到空闲磁盘块 j 后退出-*/ if(fatj.em_disk='0') break; if(j>=DISK_NUM) return(-5); fatj.em_disk='1' /*-将该空闲块设置为已分配-*/ /*-填写目录项-*/ strcpy(cur_dir->,name); cur_dir->directitemi.firstdisk=j; cur_dir->directitemi.size=ROOT_DISK_SIZE; cur_dir->directitemi.next=j;

35、 cur_dir->perty='1' /*-所创目录在虚拟磁盘上的地址(内存物理地址)-*/ cur_mkdir=(struct direct *)(fdisk+cur_dir->directitemi.firstdisk*DISKSIZE); /*-初始化目录-*/ /*-指向当前目录的目录项-*/ cur_mkdir->directitem0.sign=0; cur_mkdir->directitem0.firstdisk=cur_dir->directitemi.firstdisk; strcpy(cur_mk

36、dir->,"."); cur_mkdir->directitem0.next=cur_mkdir->directitem0.firstdisk; cur_mkdir->perty='1' cur_mkdir->directitem0.size=ROOT_DISK_SIZE; /*-指向上一级目录的目录项-*/ cur_mkdir->directitem1.sign=cur_dir->directitem0.sign;cur_mkdir->direc

37、titem1.firstdisk=cur_dir->directitem0.firstdisk; strcpy(cur_mkdir->,"."); cur_mkdir->directitem1.next=cur_mkdir->directitem1.firstdisk; cur_mkdir->perty='1' cur_mkdir->directitem1.size=ROOT_DISK_SIZE; for(i=2;i<MSD+2;i+) /*-子目录都初始

38、化为空-*/ cur_mkdir->directitemi.sign=0; cur_mkdir->directitemi.firstdisk=-1; strcpy(cur_mkdir->,""); cur_mkdir->directitemi.next=-1; cur_mkdir->perty='0' cur_mkdir->directitemi.size=0; return 0; int rmdir(char *name) int i,j,item; stru

39、ct direct *temp_dir; /*-检查当前目录项中有无该目录-*/ for(i=2;i<MSD+2;i+) if(!strcmp(cur_dir->,name) break; if(i>=MSD+2) /*-没有这个文件或目录-*/ return(-1);if(cur_dir->perty!='1')/*-删除的不是目录-*/ return(-3); /*-判断要删除的目录有无子目录-*/ temp_dir=(struct direct *)(fdisk+cur_dir->

40、directitemi.next*DISKSIZE); for(j=2;j<MSD+2;j+) if(temp_dir->directitemj.next!=-1) break; if(j<MSD+2) /*-有子目录或文件-*/ return(-2); /*-找到起始盘块号,并将其释放-*/ item=cur_dir->directitemi.firstdisk; fatitem.em_disk='0' /*-修改目录项-*/ cur_dir->directitemi.sign=0; cur_dir->directitemi.firstdi

41、sk=-1; strcpy(cur_dir->,""); cur_dir->directitemi.next=-1; cur_dir->perty='0' cur_dir->directitemi.size=0; return 0; void dir() int i; for(i=2;i<MSD+2;i+) if(cur_dir->directitemi.firstdisk!=-1) /*-如果存在子目录-*/ printf("%st",cu

42、r_dir->); if(cur_dir->perty='0') /*-文件-*/ printf("%dttn",cur_dir->directitemi.size); else printf("t<目录>tn"); int cd(char *name) int i,j,item; char *str; char *temp,*point,*point1; struct direct *temp_dir; temp_dir=cur_dir; str

43、=name; if(!strcmp("",name) cur_dir = root; strcpy(bufferdir,"Root:"); return 0; temp = (char *)malloc(DIR_MAXSIZE*sizeof(char);/*-最长路径名字分配空间-*/ for(i=0;i<(int)strlen(str);i+) tempi=stri; tempi='0' for(j=0;j<MSD+2;j+) /*-查找该子目录是否在当前目录中-*/ if(!strcmp(temp_dir->dire

44、,temp) break; free(temp);/*释放申请的临时空间*/ /if(temp_dir->perty!='1') /*-打开的不是目录-*/ /return(-2); if(j>=MSD+2) /*-不在当前目录-*/ return(-1); item=temp_dir->directitemj.firstdisk; /*-当前目录在磁盘中位置-*/ temp_dir=(struct direct *)(fdisk+item*DISKSIZE); if(!strcmp(".&quo

45、t;,name) if(cur_dir->directitemj-1.sign!=1) /*-如果上级目录不是根目录-*/ point=strchr(bufferdir,''); /查找字符串bufferdir中首次出现字符 的位置while(point!=NULL) point1=point+1; /*-减去''所占的空间,记录下次查找的起始地址-*/ point=strchr(point1,''); *(point1-1)='0' /*-将上一级目录删除-*/ else /if(name0 !='') b

46、ufferdir = strcat(bufferdir,""); /*-修改当前目录-*/ bufferdir = strcat(bufferdir,name); cur_dir=temp_dir; /*-将当前目录确定下来-*/ return 0; void show() printf("%s>",bufferdir); void print() printf("*n");printf("*文件系统设计*n"); printf("*t命令格式说明*n"); printf("*t

47、cd 目录名更改当前目录*n"); printf("*tmkdir 目录名创建子目录*n"); printf("*trmdir 目录名删除子目录*n"); printf("*tdir显示当前目录的子目录*n"); printf("*tcreate 文件名创建文件*n"); printf("*tdel 文件名删除文件*n"); printf("*topen 文件名打开文件*n"); printf("*tclose 文件名关闭文件*n"); prin

48、tf("*tread读文件*n"); printf("*twrite写文件*n"); printf("*texit退出系统*n"); printf("*n"); void main() FILE *fp; char ch; char a100; char code1110; char name10; int i,flag,r_size; char *contect; contect = (char *)malloc(MAX_WRITE*sizeof(char); if(fp=fopen("disk.dat

49、","rb")=NULL) printf("You have not format,Do you want format?(y/n)"); scanf("%c",&ch); if(ch='y') initfile(); printf("Successfully format! n"); else return; enter();print(); show(); strcpy(code0,"exit"); strcpy(code1,"create"); strcpy(code2,"open"); strcpy(code3,"close"); strcpy(code4,"write"); strcpy(code5,"read"); strcpy(code6,"del"); s