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;                       //i节点
	struct direct dir_buf[BLOCKSIZ/(DIRSIZ+2)];//目录项结构
	unsigned int block_buf[BLOCKSIZ/sizeof(int)];
	char *buf;
	int i,j;
	
	/* creat the file system file*/
	fd=fopen("filesystem","rwb");
	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;//di_mode存取权限
	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");
}