2022年操作系统-文件系统源代码 2.pdf

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1、#include#include#include#include#define BLOCKSIZE 1024#define SIZE 1024000#define END 65535#define FREE 0#define ROOTBLOCKNUM 2#define MAXOPENFILE 10 typedef struct FCB/unsigned char filename8;char exname3;unsigned char attribute;char reserve10;/me:保留区（图 3-2 MS-DOS的文件控制块）unsigned short time;unsigned

2、 short data;unsigned short first;unsigned long length;fcb;typedef struct FAT unsigned short id;fat;typedef struct USEROPEN fcb openfileMAXOPENFILE;char dirMAXOPENFILE80;/me:用来记录每个打开文件所在的目录名，以方便用户打开不同目录下具有相同文件名的不同文件。/me:即，相应打开文件所在的目录名，这样方便快速检查出指定文件是否已经打开int count;useropen;typedef struct BLOCK0/*引导块内容

3、*/char information200;/赋值 50 时本身已经越界unsigned char*startblock;/me:虚拟磁盘上数据区开始位置block0;名师资料总结-精品资料欢迎下载-名师精心整理-第 1 页，共 21 页 -unsigned char*myvhard;useropen*openfilelist;char currentdir80;/me:记录当前目录的目录名（包括目录的路径）unsigned char*startp;/me:记录虚拟磁盘上数据区开始位置void initsys();void format();void startsys();void exits

4、ys();void create();int open(char*filename);void close(int fd);void mywrite(int fd,char*buff);void myread(int fd,char*buff);void deletefile(char*filename);void ls();void listopenfile();void cd(char*dirname);/系统初始化：创建虚盘和格式化虚盘void initsys()myvhard=(unsigned char*)malloc(SIZE);memset(myvhard,0,SIZE);for

5、mat();void format()FILE*fp;time_t*now;struct tm*nowtime;unsigned char*p;fat*fat1,*fat2;fcb*root;int i,a;block0*b0;now=(time_t*)malloc(sizeof(time_t);p=myvhard;b0=(block0*)p;strcpy(b0-information,My filesystem,version0.01,blocksize is 1K,whole size is 1000K,emulate FAT16,Max open file number is 10);名

6、师资料总结-精品资料欢迎下载-名师精心整理-第 2 页，共 21 页 -/printf(n%s,b0-information);p+=BLOCKSIZE;/me:将虚拟磁盘的第一块分配给了引导块/me:给两个 FAT各分配两个盘块fat1=(fat*)(p);fat2=(fat*)(p+BLOCKSIZE*2);/me:对于每个 FAT 中，前面 5 个块设置为已分配，后面 995个块设置为空闲；/me:即，将两个 fat 表的前 5 个表项的 id 赋值 END,第 6 项为的 id 赋值 6（指向虚拟磁盘的第 6 块（即根目录文件所在块）fat1-id=END;fat2-id=END;fa

7、t1+;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+;/me:从第 7 个表项开始，初始化全部是空闲的for(i=7;ifilename,.);strcpy(root-exname,di);root-attri

8、bute=40;/me:表示为目录文件time(now);nowtime=localtime(now);root-time=nowtime-tm_hour*2048+nowtime-tm_min*32+nowtime-tm_sec/2;root-data=(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

9、;time(now);nowtime=localtime(now);root-time=nowtime-tm_hour*2048+nowtime-tm_min*32+nowtime-tm_sec/2;root-data=(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;ifilename0=0;a=BLOCKSIZE*2/sizeof(fcb);fp=fopen(c:myfsys,w);b0-startblock=

10、p+BLOCKSIZE*4;/me:虚拟磁盘上数据区开始位置fwrite(myvhard,SIZE,1,fp);fclose(fp);free(myvhard);名师资料总结-精品资料欢迎下载-名师精心整理-第 4 页，共 21 页 -/格式化之后填充初始内容void startsys()FILE*fp;int i;openfilelist=(useropen*)malloc(sizeof(useropen);memset(openfilelist,0,sizeof(useropen);fp=fopen(c:myfsys,r);myvhard=(unsigned char*)malloc(SI

11、ZE);memset(myvhard,0,SIZE);fread(myvhard,SIZE,1,fp);strcpy(openfilelist-openfile0.filename,root);strcpy(openfilelist-openfile0.exname,di);openfilelist-openfile0.attribute=168;openfilelist-openfile0.time=(fcb*)(myvhard+5*BLOCKSIZE)-time;openfilelist-openfile0.data=(fcb*)(myvhard+5*BLOCKSIZE)-data;ope

12、nfilelist-openfile0.first=(fcb*)(myvhard+5*BLOCKSIZE)-first;openfilelist-openfile0.length=(fcb*)(myvhard+5*BLOCKSIZE)-length;openfilelist-count=1;strcpy(currentdir,root);strcpy(openfilelist-dir0,currentdir);for(i=6;istartblock;fclose(fp);void exitsys()FILE*fp;fp=fopen(c:myfsys,w);fwrite(myvhard,SIZE

13、,1,fp);free(myvhard);free(openfilelist);fclose(fp);/创建文件或目录void create()名师资料总结-精品资料欢迎下载-名师精心整理-第 5 页，共 21 页 -time_t*now;struct tm*nowtime;char current8;fcb*freefcb,*updir,*p;/me:前者指向分配的空闲FCB，后者指向自身在其父目录的 fcb 位置int i,j,k,m,flag,b;unsigned short index;fat*fat1,*fat2,*fatcurrent1,*fatcurrent2;now=(time

14、_t*)malloc(sizeof(time_t);if(openfilelist-count=MAXOPENFILE)printf(open too many files!n);return;flag=0;/me:找到当前所在目录for(i=80;i=0;i-)if(currentdiri=)flag+;if(flag=2)break;i+;/me:找到当前目录的上一目录for(j=0;currentdiri!=;i+,j+)currentj=currentdiri;currentj=0;/me:通过检查 attribute 位的末三位是不是8 来确定文件类型（目录文件还是数据文件）for(

15、i=0;iopenfilei.attribute&8)=8)break;fat1=(fat*)(myvhard+BLOCKSIZE);index=openfilelist-openfilei.first;freefcb=(fcb*)(myvhard+openfilelist-openfilei.first*BLOCKSIZE);for(m=0;mopenfilei.length/BLOCKSIZE+1;m+)名师资料总结-精品资料欢迎下载-名师精心整理-第 6 页，共 21 页 -for(j=0;jfilename0=0)break;freefcb+;if(j=32)freefcb=(fcb*

16、)(myvhard+fat1index.id);index=fat1index.id;if(strcmp(currentdir,root)!=0)updir=(fcb*)(myvhard+openfilelist-openfilei.first*BLOCKSIZE);if(j=openfilelist-openfilei.length/32)for(k=0;kopenfilei.length/32;j+)if(strcmp(updir-filename,.)=0)break;updir+;fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(myvhard+BL

17、OCKSIZE*3);for(m=7;mid=FREE)break;fat1+;fat2+;fatcurrent1=(fat*)(myvhard+BLOCKSIZE);fatcurrent2=(fat*)(myvhard+BLOCKSIZE*3);index=openfilelist-openfilei.first;while(fatcurrent1index.id!=END)index=fatcurrent1index.id;if(m=SIZE/BLOCKSIZE)名师资料总结-精品资料欢迎下载-名师精心整理-第 7 页，共 21 页 -printf(cant creat filen);re

18、turn;fatcurrent1index.id=m;fatcurrent2index.id=m;fatcurrent1m.id=END;fatcurrent2m.id=END;for(k=0;klength/32;k+)if(strcmp(updir-filename,currentdir)=0)break;updir+;fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(myvhard+BLOCKSIZE*3);for(m=0;mid=FREE)break;fat1+;fat2+;fat1-id=END;fat2-id=END;updir=(fcb*)(m

19、yvhard+openfilelist-openfilei.first*BLOCKSIZE);updir-length+=sizeof(fcb);updir+;updir-length+=sizeof(fcb);updir-;for(k=0;kopenfilei.length/32;j+)if(strcmp(updir-filename,.)=0)break;updir+;updir=(fcb*)(myvhard+updir-first*BLOCKSIZE);for(k=0;klength/32;k+)if(strcmp(updir-filename,currentdir)=0)名师资料总结-

20、精品资料欢迎下载-名师精心整理-第 8 页，共 21 页 -break;updir+;updir-length+=sizeof(fcb);else updir=(fcb*)(myvhard+openfilelist-openfilei.first*BLOCKSIZE);updir-length+=sizeof(fcb);updir+;updir-length+=sizeof(fcb);fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(myvhard+BLOCKSIZE*3);for(m=0;mid=FREE)break;fat1+;fat2+;fat1-id

21、=END;fat2-id=END;openfilelist-openfilei.length+=sizeof(fcb);printf(please input filename:);scanf(%s,freefcb-filename);printf(please input filetype:);scanf(%s,freefcb-exname);freefcb-attribute=0;if(strcmp(freefcb-exname,di)=0)freefcb-attribute+=8;p=(fcb*)(myvhard+m*BLOCKSIZE);strcpy(p-filename,.);str

22、cpy(p-exname,di);p-attribute=40;time(now);nowtime=localtime(now);p-time=nowtime-tm_hour*2048+nowtime-tm_min*32+nowtime-tm_sec/2;名师资料总结-精品资料欢迎下载-名师精心整理-第 9 页，共 21 页 -p-data=(nowtime-tm_year-80)*512+(nowtime-tm_mon+1)*32+nowtime-tm_mday;p-first=m;p-length=2*sizeof(fcb);p+;strcpy(p-filename,.);strcpy(p

23、-exname,di);p-attribute=40;time(now);nowtime=localtime(now);p-time=nowtime-tm_hour*2048+nowtime-tm_min*32+nowtime-tm_sec/2;p-data=(nowtime-tm_year-80)*512+(nowtime-tm_mon+1)*32+nowtime-tm_mday;p-first=openfilelist-openfilei.first;p-length=2*sizeof(fcb);freefcb-length=2*sizeof(fcb);printf(is this fil

24、e readonly?(1 or 0);scanf(%d,&b);if(b=1)freefcb-attribute+=128;printf(is this file hide?(1 or 0);scanf(%d,&b);if(b=1)freefcb-attribute+=64;printf(is this file system?(1 or 0);scanf(%d,&b);if(b=1)freefcb-attribute+=32;time(now);nowtime=localtime(now);freefcb-time=nowtime-tm_hour*2048+nowtime-tm_min*3

25、2+nowtime-tm_sec/2;freefcb-data=(nowtime-tm_year-80)*512+(nowtime-tm_mon+1)*32+nowtime-tm_mday;名师资料总结-精品资料欢迎下载-名师精心整理-第 10 页，共 21 页 -freefcb-first=m;if(freefcb-attribute&8)!=8)freefcb-length=0;open(freefcb-filename);void ls()int i,l;fcb*current;for(i=0;iopenfilei.attribute&8)=8)break;current=(fcb*)(

26、myvhard+openfilelist-openfilei.first*BLOCKSIZE);l=openfilelist-openfilei.length/sizeof(fcb);for(i=0;ifilename,current-exname,current-time/2048,(current-time%2048)/32,(current-time%32)*2,current-data/512+1980,current-data%512/32,current-data%32,current-length);void listopenfile()int i;for(i=0;icount;

27、i+)printf(%d.%s%s.%sn,i,openfilelist-diri,openfilelist-openfilei.filename,openfilelist-openfilei.exname);int open(char*filename)int i,m,j,index,flag;fat*fat1;fcb*nowfile;名师资料总结-精品资料欢迎下载-名师精心整理-第 11 页，共 21 页 -flag=0;if(openfilelist-count=MAXOPENFILE)printf(open too many files!n);return-1;for(i=0;iope

28、nfilei.attribute&8)=8)break;fat1=(fat*)(myvhard+BLOCKSIZE);index=openfilelist-openfilei.first;nowfile=(fcb*)(myvhard+openfilelist-openfilei.first*BLOCKSIZE);for(m=0;mopenfilei.length/BLOCKSIZE+1;m+)for(j=0;jfilename,filename)=0)flag=1;break;nowfile+;if(j=32)nowfile=(fcb*)(myvhard+fat1index.id);index

29、=fat1index.id;if(flag=0)printf(file%s doesnt existn,filename);return-1;strcpy(openfilelist-openfileopenfilelist-count.filename,nowfile-filename);strcpy(openfilelist-openfileopenfilelist-count.exname,nowfile-exname);openfilelist-openfileopenfilelist-count.attribute=nowfile-attribute;openfilelist-open

30、fileopenfilelist-count.time=nowfile-time;openfilelist-openfileopenfilelist-count.data=nowfile-data;openfilelist-openfileopenfilelist-count.first=nowfile-first;openfilelist-openfileopenfilelist-count.length=nowfile-length;strcpy(openfilelist-diropenfilelist-count,currentdir);名师资料总结-精品资料欢迎下载-名师精心整理-第

31、12 页，共 21 页 -openfilelist-count+;listopenfile();return openfilelist-count-1;void close(int fd)int i;if(fd=openfilelist-count)printf(file doesnt existn);return;for(i=fd;icount-1;i+)strcpy(openfilelist-openfilei.filename,openfilelist-openfilei+1.filename);strcpy(openfilelist-openfilei.exname,openfilel

32、ist-openfilei+1.exname);openfilelist-openfilei.attribute=openfilelist-openfilei+1.attribute;openfilelist-openfilei.time=openfilelist-openfilei+1.time;openfilelist-openfilei.data=openfilelist-openfilei+1.data;openfilelist-openfilei.first=openfilelist-openfilei+1.first;openfilelist-openfilei.length=op

33、enfilelist-openfilei+1.length;strcpy(openfilelist-diri,openfilelist-diri+1);openfilelist-count-;/写文件void mywrite(int fd,char*buff)unsigned char*p;int i,j,newid,index,size1,size2,size;fcb*temp;fat*fat1,*fat2;char dir10,*q;if(fd=openfilelist-count)printf(file doesnt existn);return;if(openfilelist-open

34、filefd.attribute&8)=8)printf(file is a dirfile cant writen);名师资料总结-精品资料欢迎下载-名师精心整理-第 13 页，共 21 页 -return;/写入的文字长度需要增加一个数据块if(openfilelist-openfilefd.length/BLOCKSIZE!=(openfilelist-openfilefd.length+strlen(buff)/BLOCKSIZE)fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(myvhard+3*BLOCKSIZE);for(i=7;iid=FR

35、EE)break;fat1+;fat2+;if(i=SIZE/BLOCKSIZE)printf(the hard disk is fulln);return;fat1-id=END;fat2-id=END;newid=i-1;fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(myvhard+BLOCKSIZE*3);index=openfilelist-openfilefd.first;while(fat1index.id!=END)index=fat1index.id;fat1index.id=newid;fat2index.id=newid;size1=

36、BLOCKSIZE-openfilelist-openfilefd.length%BLOCKSIZE;size2=strlen(buff)-size1;p=myvhard+index*BLOCKSIZE+openfilelist-openfilefd.length%BLOCKSIZE;for(j=0;jsize1;j+)*p=buffj;p+;p=myvhard+newid*BLOCKSIZE;for(j=0;jopenfilefd.first;while(fat1index.id!=END)index=fat1index.id;p=myvhard+index*BLOCKSIZE+openfi

37、lelist-openfilefd.length%BLOCKSIZE;for(j=0;j length;for(q=openfilelist-dirfd;*q!=0;q+)if(*q!=)dirj=*q;j+;else dirj=0;for(i=0;ifilename)=0)break;temp+;temp=(fcb*)(myvhard+temp-first*BLOCKSIZE);size=temp-length;j=0;名师资料总结-精品资料欢迎下载-名师精心整理-第 15 页，共 21 页 -for(i=0;iopenfilefd.filename,temp-filename)=0)bre

38、ak;temp+;temp-length+=strlen(buff);openfilelist-openfilefd.length=strlen(buff);/读取文件内容void myread(int fd,char*buff)unsigned char*p;int n,index,i,length,j,k;fat*fat1;fat1=(fat*)(myvhard+BLOCKSIZE);index=openfilelist-openfilefd.first;p=myvhard+openfilelist-openfilefd.first*BLOCKSIZE;n=openfilelist-ope

39、nfilefd.length/BLOCKSIZE+1;length=openfilelist-openfilefd.length;k=0;for(i=0;in;i+)for(j=0;jBLOCKSIZE&k length;j+,k+)buffk=*p;p+;p=myvhard+BLOCKSIZE*(fat1index.id);index=fat1index.id;buffk=0;/进入 dirname 目录void cd(char*dirname)int i,index,j,k,length,count,m,n;unsigned char*p;char*updir;fcb*nowfile;fa

40、t*fat1;名师资料总结-精品资料欢迎下载-名师精心整理-第 16 页，共 21 页 -count=0;updir=(char*)malloc(sizeof(char)*80);for(i=0;icount;i+)if(openfilelist-openfilei.attribute&8)=8)break;if(i=openfilelist-count)printf(dir doesnt existn);return;fat1=(fat*)(myvhard+BLOCKSIZE);index=openfilelist-openfilei.first;p=myvhard+openfilelist

41、-openfilei.first*BLOCKSIZE;nowfile=(fcb*)p;length=openfilelist-openfilei.length;for(j=0;jopenfilei.length/sizeof(fcb);j+)if(j!=0&j%32=0)nowfile=(fcb*)(myvhard+fat1index.id);index=fat1index.id;else if(strcmp(nowfile-filename,dirname)=0&(nowfile-attribute&8)=8)break;nowfile+;if(j=openfilelist-openfile

42、i.length/sizeof(fcb)printf(dir doesnt existn);return;if(strcmp(dirname,.)!=0&strcmp(dirname,.)!=0)strcpy(openfilelist-openfileopenfilelist-count.filename,nowfile-filename);strcpy(openfilelist-openfileopenfilelist-count.exname,nowfile-exname);openfilelist-openfileopenfilelist-count.attribute=nowfile-

43、attribute;openfilelist-openfileopenfilelist-count.time=nowfile-time;名师资料总结-精品资料欢迎下载-名师精心整理-第 17 页，共 21 页 -openfilelist-openfileopenfilelist-count.data=nowfile-data;openfilelist-openfileopenfilelist-count.first=nowfile-first;openfilelist-openfileopenfilelist-count.length=nowfile-length;strcpy(openfil

44、elist-diropenfilelist-count,currentdir);openfilelist-count+;else if(strcmp(dirname,.)=0&strcmp(currentdir,root)!=0)/root/count=0;for(k=80;k0;k-)if(currentdirk=&count=2)break;else if(currentdirk=)count+;updir0=currentdirk;k+;for(n=1;(kopenfileopenfilelist-count.filename,updir+1);strcpy(openfilelist-o

45、penfileopenfilelist-count.exname,nowfile-exname);openfilelist-openfileopenfilelist-count.attribute=nowfile-attribute;openfilelist-openfileopenfilelist-count.time=nowfile-time;openfilelist-openfileopenfilelist-count.data=nowfile-data;openfilelist-openfileopenfilelist-count.first=nowfile-first;openfil

46、elist-openfileopenfilelist-count.length=nowfile-length;updirn=currentdirk;updirn+1=0;strcpy(openfilelist-diropenfilelist-count,updir);openfilelist-count+;if(strcmp(currentdir,root)=0&(strcmp(dirname,.)=0|strcmp(dirname,.)=0)/;/root/else count=0;if(strcmp(dirname,.)=0)名师资料总结-精品资料欢迎下载-名师精心整理-第 18 页，共

47、21 页 -for(k=80;k0;k-)if(currentdirk=&count=1)break;else if(currentdirk=)count+;currentdirk+1=0;else if(strcmp(dirname,.)=0);else m=0;for(k=80;k0;k-)if(currentdirk=)break;for(k=k+1;dirnamem!=0;k+,m+)currentdirk=dirnamem;currentdirk=;currentdirk+1=0;close(i);/close(i);listopenfile();void deletefile(ch

48、ar*filename)int i,index,j,k,index1;/char*updir;m,length,n,fcb*p;fat*fat1,*fat2;for(i=0;icount;i+)if(openfilelist-openfilei.attribute&8)=8)break;p=(fcb*)(myvhard+openfilelist-openfilei.first);for(j=0;jopenfilei.length/sizeof(fcb);j+)名师资料总结-精品资料欢迎下载-名师精心整理-第 19 页，共 21 页 -if(strcmp(filename,p-filename)

49、=0)break;p+;if(j=openfilelist-openfilei.length/sizeof(fcb)printf(file doesnt exist cant deleten);return;for(k=0;kcount;k+)if(strcmp(openfilelist-dirk,currentdir)=0&strcmp(filename,openfilelist-openfilek.filename)=0)break;if(k!=openfilelist-count)close(k);fat1=(fat*)(myvhard+BLOCKSIZE);fat2=(fat*)(my

50、vhard+3*BLOCKSIZE);index=p-first;while(fat1index.id!=END)index1=index;index=fat1index.id;fat1index1.id=FREE;fat2index1.id=FREE;p-filename0=0;p=(fcb*)(myvhard+openfilelist-openfilei.first);p-length-=sizeof(fcb);void main()int fd;char buff1000,buff11000,dirname10;printf(FCB_size=%dn,sizeof(fcb);initsy