文件系统实验

6.1二级目录文件系统设计6.1.1目的和要求本实验的目的是通过一个简单多用户文件系统的设计，加深理解文件系统的内部功能和内部实现。6.1.2实验内容为DOS系统设计一个简单的二级文件系统。要求做到以下几点：（1）可以实现下列几条命令LOGIN用户登陆DIR列文件目录CREATE创建文件DELETE删除文件OPEN打开文件CLOSE关闭文件READ读文件WRITE写文件（2）列目录时要列出文件名，物理地址，保护码和文件长度。（3）源文件可以进行读写保护。6.1.3实验环境（1）PC兼容机（2）Windows、DOS系统（3）TC语言6.1.4实验提示（1）首先应确定文件系统的数据结构：主目录、子目录及活动文件等。主目录和子目录都以文件的形式存放于磁盘，这样便于查找和修改。（2）用户创建的文件，可以编号存储于磁盘上。如：file0,file1,file2…并以编号作为物理地址，在目录中进行登记。6.1.5实验参考代码参考程序见下（本程序需要在c:下建一个名为osfile的目录及一个名为file的子目录）：#includestdio.h#includestring.h#includeconio.h#includestdlib.h#defineMAXNAME25/*thelargestlengthofmfdname,ufdname,filename*/#defineMAXCHILD50/*thelargestchild*/#defineMAX(MAXCHILD*MAXCHILD)/*thesizeoffpaddrno*/typedefstruct/*thestructureofOSFILE*/{intfpaddr;/*filephysicaladdress*/intflength;/*filelength*/intfmode;/*filemode:0-ReadOnly;1-WriteOnly;2-ReadandWrite(default);*/charfname[MAXNAME];/*filename*/}OSFILE;typedefstruct/*thestructureofOSUFD*/{charufdname[MAXNAME];/*ufdname*/OSFILEufdfile[MAXCHILD];/*ufdownfile*/}OSUFD;typedefstruct/*thestructureofOSUFD'LOGIN*/{charufdname[MAXNAME];/*ufdname*/charufdpword[8];/*ufdpassword*/}OSUFD_LOGIN;typedefstruct/*fileopenmode*/{intifopen;/*ifopen:0-close,1-open*/intopenmode;/*0-readonly,1-writeonly,2-readandwrite,3-initial*/}OSUFD_OPENMODE;OSUFD*ufd[MAXCHILD];/*ufdandufdownfiles*/OSUFD_LOGINufd_lp;intucount=0;/*thecountofmfd'sufds*/intfcount[MAXCHILD];/*thecountofufd'sfiles*/intloginsuc=0;/*whetherloginsuccessfully*/charusername[MAXNAME];/*recordloginuser'sname22*/chardirname[MAXNAME];/*recordcurrentdirectory*/intfpaddrno[MAX];/*recordfilephysicaladdressnum*/OSUFD_OPENMODEifopen[MAXCHILD][MAXCHILD];/*recordfileopen/close*/intwgetchar;/*whethergetchar()*/FILE*fp_mfd,*fp_ufd,*fp_file_p,*fp_file;voidmain(){inti,j,choice1;charchoice[50];/*choiceoperation:dir,create,delete,open,delete,modify,read,write*/intchoiceend=1;/*whetherchoiceend*/char*rtrim(char*str);/*removethetrailingblanks.*/char*ltrim(char*str);/*removetheheadingblanks.*/voidLoginF();/*LOGINFileSystem*/voidDirF();/*DirFileSystem*/voidCdF();/*ChangeDir*/voidCreateF();/*CreateFile*/voidDeleteF();/*DeleteFile*/voidModifyFM();/*ModifyFileMode*/voidOpenF();/*OpenFile*/voidCloseF();/*CloseFile*/voidReadF();/*ReadFile*/voidWriteF();/*WriteFile*/voidQuitF();/*QuitFileSystem*/voidhelp();if((fp_mfd=fopen(c:\\osfile\\mfd,rb))==NULL){fp_mfd=fopen(c:\\osfile\\mfd,wb);fclose(fp_mfd);}for(i=0;iMAX;i++)fpaddrno[i]=0;//textattr(BLACK*16|WHITE);system(cls);//clrscr();/*clearscreen*/LoginF();/*userlogin*///clrscr();system(cls);if(loginsuc==1)/*LoginSuccessfully*/{while(1){wgetchar=0;if(choiceend==1){printf(\n\nC:\\%s,strupr(dirname));}//strupr将所有小写字母转换成大写elseprintf(Badcommandorfilename.\nC:\\%s,strupr(username));gets(choice);strcpy(choice,ltrim(rtrim(strlwr(choice))));//strlwr将所有大写字母转换成小写if(strcmp(choice,dir)==0)choice1=1;elseif(strcmp(choice,creat)==0)choice1=2;elseif(strcmp(choice,delete)==0)choice1=3;elseif(strcmp(choice,attrib)==0)choice1=4;elseif(strcmp(choice,open)==0)choice1=5;elseif(strcmp(choice,close)==0)choice1=6;elseif(strcmp(choice,read)==0)choice1=7;elseif(strcmp(choice,modify)==0)choice1=8;elseif(strcmp(choice,exit)==0)choice1=9;elseif(strcmp(choice,cls)==0)choice1=10;elseif(strcmp(choice,cd)==0)choice1=11;elseif(strcmp(choice,help)==0)choice1=20;elsechoice1=12;switch(choice1){case1:DirF();choiceend=1;break;case2:CreateF();choiceend=1;if(!wgetchar)getchar();break;case3:DeleteF();choiceend=1;if(!wgetchar)getchar();break;case4:ModifyFM();choiceend=1;if(!wgetchar)getchar();break;case5:choiceend=1;OpenF();if(!wgetchar)getchar();break;case6:choiceend=1;CloseF();if(!wgetchar)getchar();break;case7:choiceend=1;ReadF();if(!wgetchar)getchar();break;case8:choiceend=1;WriteF();if(!wgetchar)getchar();break;case9:printf(\nYouhaveexitedthissystem.);QuitF();exit(0);break;case10:choiceend=1;system(cls);/*clrscr();*/break;case11:CdF();choiceend=1;break;case20:help();choiceend=1;break;default:choiceend=0;}}}elseprintf(\nAccessdenied.);}voidhelp(void){printf(\nTheCommandList\n);printf(\nCdAttribCreatModifyReadOpenClsDeleteExitClose\n);}char*rtrim(char*str)/*removethetrailingblanks.*/{intn=strlen(str)-1;while(n=0){if(*(str+n)!=''){*(str+n+1)='\0';break;}elsen--;}if(n0)str[0]='\0';returnstr;}char*ltrim(char*str)/*removetheheadingblanks.*/{char*rtrim(char*str);strrev(str);//将所有字母反向排列rtrim(str);strrev(str);returnstr;}voidLoginF()/*LOGINFileSystem*/{charloginame[MAXNAME],loginpw[9],logincpw[9],str[50];inti,j,flag=1;chara[25];intfindout;/*loginusernotexist*/char*rtrim(char*str);/*removethetrailingblanks.*/char*ltrim(char*str);/*removetheheadingblanks.*/voidInputPW(char*password);/*inputpassword,use'*'replace*/voidSetPANo(intRorW);/*Setphysicaladdressnum*/while(1){findout=0;printf(\n\nLoginName:);gets(loginame);ltrim(rtrim(loginame));fp_mfd=fopen(c:\\osfile\\mfd,rb);for(i=0;fread(&ufd_lp,sizeof(OSUFD_LOGIN),1,fp_mfd)!=0;i++)if(strcmp(strupr(ufd_lp.ufdname),strupr(loginame))==0){findout=1;strcpy(logincpw,ufd_lp.ufdpword);}fclose(fp_mfd);if(findout==1)/*userexist*/{printf(LoginPassword:);