1 /*
2 * dir.c
3 *
4 * PURPOSE
5 * Directory handling routines for the OSTA-UDF(tm) filesystem.
6 *
7 * COPYRIGHT
8 * This file is distributed under the terms of the GNU General Public
9 * License (GPL). Copies of the GPL can be obtained from:
10 * ftp://prep.ai.mit.edu/pub/gnu/GPL
11 * Each contributing author retains all rights to their own work.
12 *
13 * (C) 1998-2004 Ben Fennema
14 *
15 * HISTORY
16 *
17 * 10/05/98 dgb Split directory operations into its own file
18 * Implemented directory reads via do_udf_readdir
19 * 10/06/98 Made directory operations work!
20 * 11/17/98 Rewrote directory to support ICBTAG_FLAG_AD_LONG
21 * 11/25/98 blf Rewrote directory handling (readdir+lookup) to support reading
22 * across blocks.
23 * 12/12/98 Split out the lookup code to namei.c. bulk of directory
24 * code now in directory.c:udf_fileident_read.
25 */
26
27 #include "udfdecl.h"
28
29 #include <linux/string.h>
30 #include <linux/errno.h>
31 #include <linux/mm.h>
32 #include <linux/slab.h>
33 #include <linux/bio.h>
34 #include <linux/iversion.h>
35
36 #include "udf_i.h"
37 #include "udf_sb.h"
38
39
udf_readdir(struct file * file,struct dir_context * ctx)40 static int udf_readdir(struct file *file, struct dir_context *ctx)
41 {
42 struct inode *dir = file_inode(file);
43 struct udf_inode_info *iinfo = UDF_I(dir);
44 struct udf_fileident_bh fibh = { .sbh = NULL, .ebh = NULL};
45 struct fileIdentDesc *fi = NULL;
46 struct fileIdentDesc cfi;
47 udf_pblk_t block, iblock;
48 loff_t nf_pos, emit_pos = 0;
49 int flen;
50 unsigned char *fname = NULL, *copy_name = NULL;
51 unsigned char *nameptr;
52 uint16_t liu;
53 uint8_t lfi;
54 loff_t size = udf_ext0_offset(dir) + dir->i_size;
55 struct buffer_head *tmp, *bha[16];
56 struct kernel_lb_addr eloc;
57 uint32_t elen;
58 sector_t offset;
59 int i, num, ret = 0;
60 struct extent_position epos = { NULL, 0, {0, 0} };
61 struct super_block *sb = dir->i_sb;
62 bool pos_valid = false;
63
64 if (ctx->pos == 0) {
65 if (!dir_emit_dot(file, ctx))
66 return 0;
67 ctx->pos = 1;
68 }
69 nf_pos = (ctx->pos - 1) << 2;
70 if (nf_pos >= size)
71 goto out;
72
73 /*
74 * Something changed since last readdir (either lseek was called or dir
75 * changed)? We need to verify the position correctly points at the
76 * beginning of some dir entry so that the directory parsing code does
77 * not get confused. Since UDF does not have any reliable way of
78 * identifying beginning of dir entry (names are under user control),
79 * we need to scan the directory from the beginning.
80 */
81 if (!inode_eq_iversion(dir, file->f_version)) {
82 emit_pos = nf_pos;
83 nf_pos = 0;
84 } else {
85 pos_valid = true;
86 }
87
88 fname = kmalloc(UDF_NAME_LEN, GFP_NOFS);
89 if (!fname) {
90 ret = -ENOMEM;
91 goto out;
92 }
93
94 if (nf_pos == 0)
95 nf_pos = udf_ext0_offset(dir);
96
97 fibh.soffset = fibh.eoffset = nf_pos & (sb->s_blocksize - 1);
98 if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
99 if (inode_bmap(dir, nf_pos >> sb->s_blocksize_bits,
100 &epos, &eloc, &elen, &offset)
101 != (EXT_RECORDED_ALLOCATED >> 30)) {
102 ret = -ENOENT;
103 goto out;
104 }
105 block = udf_get_lb_pblock(sb, &eloc, offset);
106 if ((++offset << sb->s_blocksize_bits) < elen) {
107 if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_SHORT)
108 epos.offset -= sizeof(struct short_ad);
109 else if (iinfo->i_alloc_type ==
110 ICBTAG_FLAG_AD_LONG)
111 epos.offset -= sizeof(struct long_ad);
112 } else {
113 offset = 0;
114 }
115
116 if (!(fibh.sbh = fibh.ebh = udf_tread(sb, block))) {
117 ret = -EIO;
118 goto out;
119 }
120
121 if (!(offset & ((16 >> (sb->s_blocksize_bits - 9)) - 1))) {
122 i = 16 >> (sb->s_blocksize_bits - 9);
123 if (i + offset > (elen >> sb->s_blocksize_bits))
124 i = (elen >> sb->s_blocksize_bits) - offset;
125 for (num = 0; i > 0; i--) {
126 block = udf_get_lb_pblock(sb, &eloc, offset + i);
127 tmp = udf_tgetblk(sb, block);
128 if (tmp && !buffer_uptodate(tmp) && !buffer_locked(tmp))
129 bha[num++] = tmp;
130 else
131 brelse(tmp);
132 }
133 if (num) {
134 ll_rw_block(REQ_OP_READ, REQ_RAHEAD, num, bha);
135 for (i = 0; i < num; i++)
136 brelse(bha[i]);
137 }
138 }
139 }
140
141 while (nf_pos < size) {
142 struct kernel_lb_addr tloc;
143 loff_t cur_pos = nf_pos;
144
145 /* Update file position only if we got past the current one */
146 if (nf_pos >= emit_pos) {
147 ctx->pos = (nf_pos >> 2) + 1;
148 pos_valid = true;
149 }
150
151 fi = udf_fileident_read(dir, &nf_pos, &fibh, &cfi, &epos, &eloc,
152 &elen, &offset);
153 if (!fi)
154 goto out;
155 /* Still not at offset where user asked us to read from? */
156 if (cur_pos < emit_pos)
157 continue;
158
159 liu = le16_to_cpu(cfi.lengthOfImpUse);
160 lfi = cfi.lengthFileIdent;
161
162 if (fibh.sbh == fibh.ebh) {
163 nameptr = fi->fileIdent + liu;
164 } else {
165 int poffset; /* Unpaded ending offset */
166
167 poffset = fibh.soffset + sizeof(struct fileIdentDesc) + liu + lfi;
168
169 if (poffset >= lfi) {
170 nameptr = (char *)(fibh.ebh->b_data + poffset - lfi);
171 } else {
172 if (!copy_name) {
173 copy_name = kmalloc(UDF_NAME_LEN,
174 GFP_NOFS);
175 if (!copy_name) {
176 ret = -ENOMEM;
177 goto out;
178 }
179 }
180 nameptr = copy_name;
181 memcpy(nameptr, fi->fileIdent + liu,
182 lfi - poffset);
183 memcpy(nameptr + lfi - poffset,
184 fibh.ebh->b_data, poffset);
185 }
186 }
187
188 if ((cfi.fileCharacteristics & FID_FILE_CHAR_DELETED) != 0) {
189 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNDELETE))
190 continue;
191 }
192
193 if ((cfi.fileCharacteristics & FID_FILE_CHAR_HIDDEN) != 0) {
194 if (!UDF_QUERY_FLAG(sb, UDF_FLAG_UNHIDE))
195 continue;
196 }
197
198 if (cfi.fileCharacteristics & FID_FILE_CHAR_PARENT) {
199 if (!dir_emit_dotdot(file, ctx))
200 goto out;
201 continue;
202 }
203
204 flen = udf_get_filename(sb, nameptr, lfi, fname, UDF_NAME_LEN);
205 if (flen < 0)
206 continue;
207
208 tloc = lelb_to_cpu(cfi.icb.extLocation);
209 iblock = udf_get_lb_pblock(sb, &tloc, 0);
210 if (!dir_emit(ctx, fname, flen, iblock, DT_UNKNOWN))
211 goto out;
212 } /* end while */
213
214 ctx->pos = (nf_pos >> 2) + 1;
215 pos_valid = true;
216
217 out:
218 if (pos_valid)
219 file->f_version = inode_query_iversion(dir);
220 if (fibh.sbh != fibh.ebh)
221 brelse(fibh.ebh);
222 brelse(fibh.sbh);
223 brelse(epos.bh);
224 kfree(fname);
225 kfree(copy_name);
226
227 return ret;
228 }
229
230 /* readdir and lookup functions */
231 const struct file_operations udf_dir_operations = {
232 .llseek = generic_file_llseek,
233 .read = generic_read_dir,
234 .iterate_shared = udf_readdir,
235 .unlocked_ioctl = udf_ioctl,
236 .fsync = generic_file_fsync,
237 };
238