access.c

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/*访问控制函数access()(文件名access.c)*/

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

unsigned int access (user_id, inode, mode)
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 & ODIREAD) &&(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;
defualt:
		return 0;
}
}