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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * dir.c4 *5 * PURPOSE6 * Directory handling routines for the OSTA-UDF(tm) filesystem.7 *8 * COPYRIGHT9 * (C) 1998-2004 Ben Fennema10 *11 * HISTORY12 *13 * 10/05/98 dgb Split directory operations into its own file14 * Implemented directory reads via do_udf_readdir15 * 10/06/98 Made directory operations work!16 * 11/17/98 Rewrote directory to support ICBTAG_FLAG_AD_LONG17 * 11/25/98 blf Rewrote directory handling (readdir+lookup) to support reading18 * across blocks.19 * 12/12/98 Split out the lookup code to namei.c. bulk of directory20 * code now in directory.c:udf_fileident_read.21 */22 23#include "udfdecl.h"24 25#include <linux/string.h>26#include <linux/errno.h>27#include <linux/mm.h>28#include <linux/slab.h>29#include <linux/bio.h>30#include <linux/iversion.h>31 32#include "udf_i.h"33#include "udf_sb.h"34 35static int udf_readdir(struct file *file, struct dir_context *ctx)36{37 struct inode *dir = file_inode(file);38 loff_t nf_pos, emit_pos = 0;39 int flen;40 unsigned char *fname = NULL;41 int ret = 0;42 struct super_block *sb = dir->i_sb;43 bool pos_valid = false;44 struct udf_fileident_iter iter;45 46 if (ctx->pos == 0) {47 if (!dir_emit_dot(file, ctx))48 return 0;49 ctx->pos = 1;50 }51 nf_pos = (ctx->pos - 1) << 2;52 if (nf_pos >= dir->i_size)53 goto out;54 55 /*56 * Something changed since last readdir (either lseek was called or dir57 * changed)? We need to verify the position correctly points at the58 * beginning of some dir entry so that the directory parsing code does59 * not get confused. Since UDF does not have any reliable way of60 * identifying beginning of dir entry (names are under user control),61 * we need to scan the directory from the beginning.62 */63 if (!inode_eq_iversion(dir, *(u64 *)file->private_data)) {64 emit_pos = nf_pos;65 nf_pos = 0;66 } else {67 pos_valid = true;68 }69 70 fname = kmalloc(UDF_NAME_LEN, GFP_KERNEL);71 if (!fname) {72 ret = -ENOMEM;73 goto out;74 }75 76 for (ret = udf_fiiter_init(&iter, dir, nf_pos);77 !ret && iter.pos < dir->i_size;78 ret = udf_fiiter_advance(&iter)) {79 struct kernel_lb_addr tloc;80 udf_pblk_t iblock;81 82 /* Still not at offset where user asked us to read from? */83 if (iter.pos < emit_pos)84 continue;85 86 /* Update file position only if we got past the current one */87 pos_valid = true;88 ctx->pos = (iter.pos >> 2) + 1;89 90 if (iter.fi.fileCharacteristics & FID_FILE_CHAR_DELETED) {91 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))92 continue;93 }94 95 if (iter.fi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) {96 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))97 continue;98 }99 100 if (iter.fi.fileCharacteristics & FID_FILE_CHAR_PARENT) {101 if (!dir_emit_dotdot(file, ctx))102 goto out_iter;103 continue;104 }105 106 flen = udf_get_filename(sb, iter.name,107 iter.fi.lengthFileIdent, fname, UDF_NAME_LEN);108 if (flen < 0)109 continue;110 111 tloc = lelb_to_cpu(iter.fi.icb.extLocation);112 iblock = udf_get_lb_pblock(sb, &tloc, 0);113 if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))114 goto out_iter;115 }116 117 if (!ret) {118 ctx->pos = (iter.pos >> 2) + 1;119 pos_valid = true;120 }121out_iter:122 udf_fiiter_release(&iter);123out:124 if (pos_valid)125 *(u64 *)file->private_data = inode_query_iversion(dir);126 kfree(fname);127 128 return ret;129}130 131static int udf_dir_open(struct inode *inode, struct file *file)132{133 file->private_data = kzalloc(sizeof(u64), GFP_KERNEL);134 if (!file->private_data)135 return -ENOMEM;136 return 0;137}138 139static int udf_dir_release(struct inode *inode, struct file *file)140{141 kfree(file->private_data);142 return 0;143}144 145static loff_t udf_dir_llseek(struct file *file, loff_t offset, int whence)146{147 return generic_llseek_cookie(file, offset, whence,148 (u64 *)file->private_data);149}150 151/* readdir and lookup functions */152const struct file_operations udf_dir_operations = {153 .open = udf_dir_open,154 .release = udf_dir_release,155 .llseek = udf_dir_llseek,156 .read = generic_read_dir,157 .iterate_shared = udf_readdir,158 .unlocked_ioctl = udf_ioctl,159 .fsync = generic_file_fsync,160};161