/* *  linux/fs/xiafs/dir.c *   *  Copyright (C) Q. Frank Xia, 1993. *   *  Based on Linus' minix/dir.c *  Copyright (C) Linus Torvalds, 1991, 1992. * *  This software may be redistributed per Linux Copyright. */#include <linux/sched.h>#include <linux/errno.h>#include <linux/kernel.h>#include <linux/fs.h>#include <linux/xia_fs.h>#include <linux/stat.h>#include <asm/segment.h>#include "xiafs_mac.h"static int xiafs_dir_read(struct inode *, struct file *, char *, int);static int xiafs_readdir(struct inode *, struct file *, void *, filldir_t);static struct file_operations xiafs_dir_operations = {    NULL,		/* lseek - default */    xiafs_dir_read,	/* read */    NULL,		/* write - bad */    xiafs_readdir,	/* readdir */    NULL,		/* select - default */    NULL,		/* ioctl - default */    NULL,		/* mmap */    NULL,		/* no special open code */    NULL,		/* no special release code */    file_fsync		/* default fsync */};/* * directories can handle most operations... */struct inode_operations xiafs_dir_inode_operations = {    &xiafs_dir_operations,	/* default directory file-ops */    xiafs_create,			/* create */    xiafs_lookup,			/* lookup */    xiafs_link,			/* link */    xiafs_unlink,			/* unlink */    xiafs_symlink,		/* symlink */    xiafs_mkdir,			/* mkdir */    xiafs_rmdir,			/* rmdir */    xiafs_mknod,			/* mknod */    xiafs_rename,			/* rename */    NULL,			/* readlink */    NULL,			/* follow_link */    NULL,			/* readpage */    NULL,			/* writepage */    NULL,			/* bmap */    xiafs_truncate,		/* truncate */    NULL			/* permission */};static int xiafs_dir_read(struct inode * inode, 			struct file * filp, char * buf, int count){  return -EISDIR;}static int xiafs_readdir(struct inode * inode, struct file * filp,	void * dirent, filldir_t filldir){    u_int offset, i;    struct buffer_head * bh;    struct xiafs_direct * de;    if (!inode || !inode->i_sb || !S_ISDIR(inode->i_mode))        return -EBADF;    if (inode->i_size & (XIAFS_ZSIZE(inode->i_sb) - 1) )        return -EBADF;    while (filp->f_pos < inode->i_size) {        offset = filp->f_pos & (XIAFS_ZSIZE(inode->i_sb) - 1);	bh = xiafs_bread(inode, filp->f_pos >> XIAFS_ZSIZE_BITS(inode->i_sb),0);	if (!bh) {	    filp->f_pos += XIAFS_ZSIZE(inode->i_sb)-offset;	    continue;	}	for (i = 0; i < XIAFS_ZSIZE(inode->i_sb) && i < offset; ) {	    de = (struct xiafs_direct *) (bh->b_data + i);	    if (!de->d_rec_len)		break;	    i += de->d_rec_len;	}	offset = i;	de = (struct xiafs_direct *) (offset + bh->b_data);		while (offset < XIAFS_ZSIZE(inode->i_sb) && filp->f_pos < inode->i_size) {	    if (de->d_ino > inode->i_sb->u.xiafs_sb.s_ninodes ||		de->d_rec_len < 12 || 		(char *)de+de->d_rec_len > XIAFS_ZSIZE(inode->i_sb)+bh->b_data ||		de->d_name_len < 1 || de->d_name_len + 8 > de->d_rec_len ||		de->d_name_len > _XIAFS_NAME_LEN ||		de->d_name[de->d_name_len] ) {	        printk("XIA-FS: bad directory entry (%s %d)\n", WHERE_ERR);		brelse(bh);		return 0;	    }  	    if (de->d_ino) {		if (!IS_RDONLY (inode)) {		    inode->i_atime=CURRENT_TIME;		    inode->i_dirt=1;		}		if (filldir(dirent, de->d_name, de->d_name_len, filp->f_pos, de->d_ino) < 0) {		    brelse(bh);		    return 0;		}	    }	    offset += de->d_rec_len;	    filp->f_pos += de->d_rec_len;	    de = (struct xiafs_direct *) (offset + bh->b_data);	}	brelse(bh);	if (offset > XIAFS_ZSIZE(inode->i_sb)) {	    printk("XIA-FS: bad directory (%s %d)\n", WHERE_ERR);	    return 0;	}    }    if (!IS_RDONLY (inode)) {	inode->i_atime=CURRENT_TIME;		    	inode->i_dirt=1;    }    return 0;}