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/*

 * linux/fs/ext2/acl.c

 *

 * Copyright (C) 1993, 1994, 1995

 * Remy Card (card@masi.ibp.fr)

 * Laboratoire MASI - Institut Blaise Pascal

 * Universite Pierre et Marie Curie (Paris VI)

 */

/*

 * This file will contain the Access Control Lists management for the

 * second extended file system.

 */

#include <linux/errno.h>

#include <linux/fs.h>

#include <linux/ext2_fs.h>

#include <linux/sched.h>

#include <linux/stat.h>

/*

 * ext2_permission ()

 *

 * Check for access rights

 */

int ext2_permission (struct inode * inode, int mask)

{

        unsigned short mode = inode->i_mode;

        /*

         * Nobody gets write access to a file on a readonly-fs

         */

        if ((mask & S_IWOTH) &&

            (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) &&

            IS_RDONLY(inode))

                return -EROFS;

        /*

         * Nobody gets write access to an immutable file

         */

        if ((mask & S_IWOTH) && IS_IMMUTABLE(inode))

                return -EACCES;

        /*

         * Special case, access is always granted for root

         */

        if (fsuser())

                return 0;

        /*

         * If no ACL, checks using the file mode

         */

        else if (current->fsuid == inode->i_uid)

                mode >>= 6;

        else if (in_group_p (inode->i_gid))

                mode >>= 3;

        if (((mode & mask & S_IRWXO) == mask))

                return 0;

        else

                return -EACCES;

}