// SPDX-License-Identifier: GPL-2.0-only/* * dir.c * * PURPOSE *  Directory handling routines for the OSTA-UDF(tm) filesystem. * * COPYRIGHT *  (C) 1998-2004 Ben Fennema * * HISTORY * *  10/05/98 dgb  Split directory operations into its own file *                Implemented directory reads via do_udf_readdir *  10/06/98      Made directory operations work! *  11/17/98      Rewrote directory to support ICBTAG_FLAG_AD_LONG *  11/25/98 blf  Rewrote directory handling (readdir+lookup) to support reading *                across blocks. *  12/12/98      Split out the lookup code to namei.c. bulk of directory *                code now in directory.c:udf_fileident_read. */ #include "udfdecl.h" #include <linux/string.h>#include <linux/errno.h>#include <linux/filelock.h>#include <linux/mm.h>#include <linux/slab.h>#include <linux/bio.h>#include <linux/iversion.h> #include "udf_i.h"#include "udf_sb.h" static int udf_readdir(struct file *file, struct dir_context *ctx){	struct inode *dir = file_inode(file);	loff_t nf_pos, emit_pos = 0;	int flen;	unsigned char *fname = NULL;	int ret = 0;	struct super_block *sb = dir->i_sb;	bool pos_valid = false;	struct udf_fileident_iter iter; 	if (ctx->pos == 0) {		if (!dir_emit_dot(file, ctx))			return 0;		ctx->pos = 1;	}	nf_pos = (ctx->pos - 1) << 2;	if (nf_pos >= dir->i_size)		goto out; 	/*	 * Something changed since last readdir (either lseek was called or dir	 * changed)?  We need to verify the position correctly points at the	 * beginning of some dir entry so that the directory parsing code does	 * not get confused. Since UDF does not have any reliable way of	 * identifying beginning of dir entry (names are under user control),	 * we need to scan the directory from the beginning.	 */	if (!inode_eq_iversion(dir, *(u64 *)file->private_data)) {		emit_pos = nf_pos;		nf_pos = 0;	} else {		pos_valid = true;	} 	fname = kmalloc(UDF_NAME_LEN, GFP_KERNEL);	if (!fname) {		ret = -ENOMEM;		goto out;	} 	for (ret = udf_fiiter_init(&iter, dir, nf_pos);	     !ret && iter.pos < dir->i_size;	     ret = udf_fiiter_advance(&iter)) {		struct kernel_lb_addr tloc;		udf_pblk_t iblock; 		/* Still not at offset where user asked us to read from? */		if (iter.pos < emit_pos)			continue; 		/* Update file position only if we got past the current one */		pos_valid = true;		ctx->pos = (iter.pos >> 2) + 1; 		if (iter.fi.fileCharacteristics & FID_FILE_CHAR_DELETED) {			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))				continue;		} 		if (iter.fi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) {			if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))				continue;		} 		if (iter.fi.fileCharacteristics & FID_FILE_CHAR_PARENT) {			if (!dir_emit_dotdot(file, ctx))				goto out_iter;			continue;		} 		flen = udf_get_filename(sb, iter.name,				iter.fi.lengthFileIdent, fname, UDF_NAME_LEN);		if (flen < 0)			continue; 		tloc = lelb_to_cpu(iter.fi.icb.extLocation);		iblock = udf_get_lb_pblock(sb, &tloc, 0);		if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))			goto out_iter;	} 	if (!ret) {		ctx->pos = (iter.pos >> 2) + 1;		pos_valid = true;	}out_iter:	udf_fiiter_release(&iter);out:	if (pos_valid)		*(u64 *)file->private_data = inode_query_iversion(dir);	kfree(fname); 	return ret;} static int udf_dir_open(struct inode *inode, struct file *file){	file->private_data = kzalloc(sizeof(u64), GFP_KERNEL);	if (!file->private_data)		return -ENOMEM;	return 0;} static int udf_dir_release(struct inode *inode, struct file *file){	kfree(file->private_data);	return 0;} static loff_t udf_dir_llseek(struct file *file, loff_t offset, int whence){	return generic_llseek_cookie(file, offset, whence,				     (u64 *)file->private_data);} /* readdir and lookup functions */const struct file_operations udf_dir_operations = {	.open			= udf_dir_open,	.release		= udf_dir_release,	.llseek			= udf_dir_llseek,	.read			= generic_read_dir,	.iterate_shared		= udf_readdir,	.unlocked_ioctl		= udf_ioctl,	.fsync			= simple_fsync,	.setlease		= generic_setlease,};