操作系统课程设计实习报告

/*----------------------------------------------------------------------------------------------*/ /*----------------------------一个单用户文件系统的实现------------------------------------------*/ /*----------------------------------------------------------------------------------------------*/ #include<stdio.h> #include<string.h> #include<stdlib.h> #define DIR_LENGTH 1024 /*路径最长可达100字节*/ #define MAX_WRITE 1024*128 /*写入文字可达128k字节*/ #define MEM_D_SIZE 1024*1024 /*1M磁盘空间*/ #define DISKSIZE 1024 /*磁盘快的大小 1K*/ #define MSD 5 /*最大子目录数 5 (类似五叉树)*/ #define DISK_NUM MEM_D_SIZE/DISKSIZE /*磁盘快数目 1024=1M/1K*/ #define FATSIZE DISK_NUM*sizeof(struct fatitem) /*FAT表大小 8K=8192B (理想应该是 1.5K)*/ #define MOFN 5 /*最大文件打开数 5 (即除根以外最大深度为5)*/ #define ROOT_DISK_NO FATSIZE/DISKSIZE+1 /*根目录起始盘快号 9*/ #define ROOT_DISK_SIZE sizeof(struct direct)/*根目录大小 196*/ /*---------------FAT表项结构-----------------------*/ 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*/ }; /*-------------------目录项结构------------------------*/ struct direct /* size 196*/ { /*-----文件控制快信息-----*/ struct FCB { char name[9]; /*文件/目录名 8位*/ char property; /*属性 1位目录 0位普通文件*/ int size; /*文件/目录字节数(原注释位盘块数)*/ 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*/ }directitem[MSD+2]; }; /*------------------文件打开表项结构--------------------------*/ struct opentable /* size 104*/ { struct openttableitem /* size 20*/ { char name[9]; /*文件名*/ int firstdisk; /*起始盘块号*/ int size; /*文件的大小*/ }openitem[MOFN]; int cur_size; /*当前打文件的数目*/ }; /*-------------------------------------------------------------------*/ 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); 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(); /*----------------------------------------------------------------------------------------------*/ /*------------------------------------------初始化文件系统--------------------------------------*/ void initfile() { fdisk = (char *)malloc(MEM_D_SIZE*sizeof(char)); /*申请 1M空间*/ format(); free(fdisk); } /*----------------------------------------------------------------------------------------------*/ /*------------------------------------------格式化----------------------------------------------*/ void format() { int i; FILE *fp; fat = (struct fatitem *)(fdisk+DISKSIZE); /*计算FAT表地址(为什么向后偏移 1k)*/ /*-----初始化FAT表------------*/ fat[0].item=-1; /*引导块*/ fat[0].em_disk='1'; for(i=1;i<ROOT_DISK_NO-1;i++) /*存放 FAT表的磁盘块号*/ { fat[i].item=i+1; fat[i].em_disk='1'; } fat[ROOT_DISK_NO-1].item=-1; fat[ROOT_DISK_NO-1].em_disk='1'; fat[ROOT_DISK_NO].item=-1; /*存放根目录的磁盘块号*/ fat[ROOT_DISK_NO].em_disk='1'; for(i=ROOT_DISK_NO+1;i<DISK_NUM;i++) { fat[i].item = -1; fat[i].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->directitem[0].sign = 1; root->directitem[0].firstdisk = ROOT_DISK_NO; strcpy(root->directitem[0].name,"."); root->directitem[0].next = root->directitem[0].firstdisk; root->directitem[0].property = '1'; root->directitem[0].size = ROOT_DISK_SIZE; /*-------指向上一级目录的目录项---------*/ root->directitem[1].sign = 1; root->directitem[1].firstdisk = ROOT_DISK_NO; strcpy(root->directitem[1].name,".."); root->directitem[1].next = root->directitem[0].firstdisk; root->directitem[1].property = '1'; root->directitem[1].size = ROOT_DISK_SIZE; for(i=2;i<MSD+2;i++) /*-子目录初始化为空-*/ { root->directitem[i].sign = 0; root->directitem[i].firstdisk = -1; strcpy(root->directitem[i].name,""); root->directitem[i].next = -1; root->directitem[i].property = '0'; root->directitem[i].size = 0; } /*-------测试写入文件的数据--------- for(i=0;i<DISK_NUM;i++) { printf("%d,%d\n",fat[i].item,fat[i].em_disk); } for(i=0;i<MSD+2;i++) { printf("%d,%s,%d,%c,%d,%d\n",root->directitem[i].firstdisk, root->directitem[i].name,root->directitem[i].next, root->directitem[i].property,root->directitem[i].sign, root->directitem[i].size); } for(i=0;i<DISK_NUM;i++) { fread(&fat[i],sizeof(struct fatitem),1,fp); printf("%d,%d\n",fat[i].em_disk,fat[i].item); } for(i=0;i<MSD+2;i++) { fread(&root->directitem[i],sizeof(struct FCB),1,fp); printf("%d,%s,%d,%c,%d,%d\n",root->directitem[i].firstdisk, root->directitem[i].name,root->directitem[i].next, root->directitem[i].property,root->directitem[i].sign, root->directitem[i].size); } ------test end-----*/ if((fp = fopen("disk.dat","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); } /*----------------------------------------------------------------------------------------------*/ /*--------------------------------进入文件系统--------------------------------------------------*/ void enter() { FILE *fp; int i; fdisk = (char *)malloc(MEM_D_SIZE*sizeof(char)); /*申请 1M空间*/ if((fp=fopen("disk.dat","rb"))==NULL) { printf("Error:\nCannot open file\n"); 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 file\n"); exit(0); } fat = (struct fatitem *)(fdisk+DISKSIZE); /*找到FAT表地址*/ root = (struct direct *)(fdisk+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_opentable.openitem[i].name,""); u_opentable.openitem[i].firstdisk = -1; u_opentable.openitem[i].size = 0; } u_opentable.cur_size = 0; cur_dir = root; /*当前目录为根目录*/ bufferdir = (char *)malloc(DIR_LENGTH*sizeof(char)); strcpy(bufferdir,"Root:"); /*显示根目录为E:*/ } /*----------------------------------------------------------------------------------------------*/ /*------------------------------------退出文件系统----------------------------------------------*/ void halt() { FILE *fp; int i; if((fp=fopen("disk.dat","wb"))==NULL) { printf("Error:\nCannot open file\n"); 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"); } fclose(fp); free(fdisk); free(bufferdir); for(i=0;i<MOFN;i++) /*撤销用户打开表 (好像没有必要,系统自动会回收)*/ { strcpy(u_opentable.openitem[i].name,""); u_opentable.openitem[i].firstdisk = 0; u_opentable.openitem[i].size = 0; } u_opentable.cur_size = 0; /*用户打开文件数清零*