format.c

操作系统实验,文件系统,c语言实现的

#include <stdio.h>
#include "filesys.h" 

format()
{
struct inode *inode;
struct direct dir_buf[BLOCKSIZ/(DIRSIZ+2)];
/*struct pwd passwd[BLOCKSIZ/(PWDSIZ+4)];*/
/*
{
       {2116,03,"dddd"},
       {2117,03,"bbbb"},
       {2118,04,"abcd"},
       {2119,04,"cccc"},
       {2220,05,"eeee"},
};
*/
/*struct filsys filsys;*/
unsigned int block_buf[BLOCKSIZ/sizeof(int)];
char *buf;
int i,j;

 /* creat the file system file*/
fd=fopen("filesystem","rwb");/*见"谭浩强，C程序设计第二版P313"*/
buf=(char *)malloc((DINODEBLK+FILEBLK+2)*BLOCKSIZ*sizeof(char));
if(buf==NULL)
{  
    printf("\nfile system file creat failed!!!\n");
    exit(0);
 }
 fseek(fd,0,SEEK_SET);
   fwrite(buf,1,(DINODEBLK+FILEBLK+2)*BLOCKSIZ*sizeof(char),fd);
   /* 0.initialize the passwd */
   pwd[0].p_uid=2116;pwd[0].p_gid=03;
   strcpy(pwd[0].password,"dddd");
   pwd[1].p_uid=2117;pwd[1].p_gid=03;
   strcpy(pwd[1].password,"bbbb");
   pwd[2].p_uid=2118;pwd[2].p_gid=04;
   strcpy(pwd[2].password,"abcd");
   pwd[3].p_uid=2119;pwd[3].p_gid=04;
   strcpy(pwd[3].password,"cccc");
   pwd[4].p_uid=2220;pwd[4].p_gid=05;
   strcpy(pwd[4].password,"eeee");

   /* 1. creat the main directory and its sub dir etc and the file password */
   inode=iget(0);    /* 0 empty dinode id */
   inode->di_mode=DIEMPTY;
   iput(inode);

   inode=iget(1);    /* l main dir id */
   inode->di_number=1;
   inode->di_mode=DEFAULTMODE | DIDIR;
   inode->di_size=3*(DIRSIZ+2);
   inode->di_addr[0]=0;    /* block 0# is used by the main directory */
   strcpy(dir_buf[0].d_name,"..");
   dir_buf[0].d_ino=1;
   strcpy(dir_buf[1].d_name,".");
   dir_buf[1].d_ino=1;
   strcpy(dir_buf[2].d_name,"etc");
   dir_buf[2].d_ino=2;
   fseek(fd,DATASTART,SEEK_SET);
   fwrite(dir_buf,1,3*(DIRSIZ+2),fd);
   iput(inode);
   inode=iget(2);    /* 2 etc dir id */
   inode->di_number=1;
   inode->di_mode=DEFAULTMODE | DIDIR;
   inode->di_size=3*(DIRSIZ+2);
   inode->di_addr[0]=1;    /* block 1# is used by the etc directory*/
   strcpy(dir_buf[0].d_name,"..");
   dir_buf[0].d_ino=1;
   strcpy(dir_buf[1].d_name,".");
   dir_buf[1].d_ino=2;
   strcpy(dir_buf[2].d_name,"password");
   dir_buf[2].d_ino=3;
   fseek(fd,DATASTART+BLOCKSIZ*1,SEEK_SET);
   fwrite(dir_buf,1,3*(DIRSIZ+2),fd);
   iput(inode);
   inode=iget(3);    /* 3 password id */
   inode->di_number=1;
   inode->di_mode=DEFAULTMODE | DIFILE;
   inode->di_size=BLOCKSIZ;
   inode->di_addr[0]=2;    /* block 2# is used by the password file */
   for(i=5;i<PWDNUM;i++)
   {
   pwd[i].p_uid=0;
   pwd[i].p_gid=0;
   strcpy(pwd[i].password,"123456789ABC");
   }
   fseek(fd,DATASTART+2*BLOCKSIZ,SEEK_SET);
   fwrite(pwd,1,BLOCKSIZ,fd);
   iput(inode);
   /* 2.initialize the superblock */
   filsys.s_isize=DINODEBLK;
   filsys.s_fsize=FILEBLK;
   filsys.s_ninode=DINODEBLK*BLOCKSIZ/DINODESIZ-4;
   filsys.s_nfree=FILEBLK-3;
   for(i=0;i<NICINOD;i++)
   {
   /* begin with 4,0,1,2,3,is used by main,etc,password*/
       filsys.s_inode[i]=4+i;
   }
   filsys.s_pinode=0;
   filsys.s_rinode=NICINOD+4;
   block_buf[NICFREE-1]=FILEBLK+1; /* FILEBLK+1 is a flag of end */
   for(i=0;i<NICFREE-1; i++)
         block_buf[NICFREE-2-i]=FILEBLK-i;
   fseek(fd,DATASTART+BLOCKSIZ*(FILEBLK-NICFREE-1),SEEK_SET);
   fwrite(block_buf,1,BLOCKSIZ,fd);
   for(i=FILEBLK-NICFREE-1;i>2;i-=NICFREE)   
   {
       for(j=0;j<NICFREE;j++)
      {
       block_buf[j]=i-j;
      }
 block_buf[j]=50;
   /*    printf("i=%0x\n",i);
       printf("fseek=%0x\n",DATASTART+BLOCKSIZ*(i-1));*/
       fseek(fd,DATASTART+BLOCKSIZ*(i-1),SEEK_SET);
       fwrite(block_buf,1,BLOCKSIZ,fd);
  }
   j=i+NICFREE;
   for(i=j ;i>2;i--)
   {   
       filsys.s_free[NICFREE-1+i-j]=i;
   }

   filsys.s_pfree=NICFREE-1-j+3;
   filsys.s_pinode=0;
   fseek(fd,BLOCKSIZ,SEEK_SET);
   fwrite(&filsys.s_isize,1,sizeof(struct filsys),fd);
   fseek(fd,BLOCKSIZ,SEEK_SET);
   fread(&filsys.s_isize,1,sizeof(struct filsys),fd);
printf("\niget(3)---->out\n");
}