access.c

操作系统实验,文件系统,c语言实现的

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

unsigned int access(unsigned int user_id,struct inode *inode,unsigned short mode)
{
	switch(mode)
	{
	case READ:
		if(inode->di_mode & ODIREAD)
			return 1;
		if((inode->di_mode & GDIREAD) && (user[user_id].u_gid==inode->di_gid)) 
			return 1;   
        if((inode->di_mode & UDIREAD) && (user[user_id].u_uid==inode->di_uid)) 
			return 1;
		return 0;
	case WRITE:
		if(inode->di_mode & ODIWRITE)  return 1;
		if((inode->di_mode & GDIWRITE)&&       
            (user[user_id].u_gid==inode->di_gid)) return 1;   
		if((inode->di_mode & UDIWRITE)&&
            (user[user_id].u_uid==inode->di_uid)) return 1;
		return 0;
	case EXICUTE:
		if(inode->di_mode & ODIEXICUTE) return 1;
		if((inode->di_mode & GDIEXICUTE)&&   
            (user[user_id].u_gid==inode->di_gid)) return 1;
		if((inode->di_mode & UDIEXICUTE)&&   
            (user[user_id].u_uid==inode->di_uid)) return 1;
		return 0;
	case DEFAULTMODE:
		return 1;
	default:
		return 0;
    }
}