1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * linux/fs/isofs/dir.c
4 *
5 * (C) 1992, 1993, 1994 Eric Youngdale Modified for ISO 9660 filesystem.
6 *
7 * (C) 1991 Linus Torvalds - minix filesystem
8 *
9 * Steve Beynon : Missing last directory entries fixed
10 * (stephen@askone.demon.co.uk) : 21st June 1996
11 *
12 * isofs directory handling functions
13 */
14 #include <linux/gfp.h>
15 #include <linux/filelock.h>
16 #include <linux/slab.h>
17 #include "isofs.h"
18 #include <linux/fileattr.h>
19
isofs_name_translate(struct iso_directory_record * de,char * new,struct inode * inode)20 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
21 {
22 char * old = de->name;
23 int len = de->name_len[0];
24 int i;
25
26 for (i = 0; i < len; i++) {
27 unsigned char c = old[i];
28 if (!c)
29 break;
30
31 if (c >= 'A' && c <= 'Z')
32 c |= 0x20; /* lower case */
33
34 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
35 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
36 break;
37
38 /* Drop trailing ';1' */
39 if (c == ';' && i == len - 2 && old[i + 1] == '1')
40 break;
41
42 /* Convert remaining ';' to '.' */
43 /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
44 if (c == ';' || c == '/')
45 c = '.';
46
47 new[i] = c;
48 }
49 return i;
50 }
51
52 /* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */
get_acorn_filename(struct iso_directory_record * de,char * retname,struct inode * inode)53 int get_acorn_filename(struct iso_directory_record *de,
54 char *retname, struct inode *inode)
55 {
56 int std;
57 unsigned char *chr;
58 int retnamlen = isofs_name_translate(de, retname, inode);
59
60 if (retnamlen == 0)
61 return 0;
62 std = sizeof(struct iso_directory_record) + de->name_len[0];
63 if (std & 1)
64 std++;
65 if (de->length[0] - std != 32)
66 return retnamlen;
67 chr = ((unsigned char *) de) + std;
68 if (strncmp(chr, "ARCHIMEDES", 10))
69 return retnamlen;
70 if ((*retname == '_') && ((chr[19] & 1) == 1))
71 *retname = '!';
72 if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
73 && ((chr[12] & 0xf0) == 0xf0)) {
74 retname[retnamlen] = ',';
75 sprintf(retname+retnamlen+1, "%3.3x",
76 ((chr[12] & 0xf) << 8) | chr[11]);
77 retnamlen += 4;
78 }
79 return retnamlen;
80 }
81
82 /*
83 * This should _really_ be cleaned up some day..
84 */
do_isofs_readdir(struct inode * inode,struct file * file,struct dir_context * ctx,char * tmpname)85 static int do_isofs_readdir(struct inode *inode, struct file *file,
86 struct dir_context *ctx,
87 char *tmpname)
88 {
89 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
90 unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
91 unsigned long block, offset, block_saved, offset_saved;
92 unsigned long inode_number = 0; /* Quiet GCC */
93 struct buffer_head *bh = NULL;
94 int len;
95 int map;
96 int first_de = 1;
97 char *p = NULL; /* Quiet GCC */
98 struct iso_directory_record *de;
99 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
100
101 offset = ctx->pos & (bufsize - 1);
102 block = ctx->pos >> bufbits;
103
104 while (ctx->pos < inode->i_size) {
105 int de_len;
106
107 if (!bh) {
108 bh = isofs_bread(inode, block);
109 if (!bh)
110 return 0;
111 }
112
113 de = (struct iso_directory_record *)(bh->b_data + offset);
114 /*
115 * If we are at the end of a block (or at its zero-padded
116 * tail), move on to the next CDROM sector. If we are at the
117 * end of the directory, we'll abort the while loop.
118 */
119 if (offset >= bufsize || de->length[0] == 0) {
120 brelse(bh);
121 bh = NULL;
122 block++;
123 ctx->pos = (loff_t)block << bufbits;
124 offset = 0;
125 continue;
126 }
127 de_len = de->length[0];
128 block_saved = block;
129 offset_saved = offset;
130 offset += de_len;
131
132 if (!isofs_dir_record_valid(de, offset_saved, bufsize)) {
133 printk(KERN_NOTICE "iso9660: Corrupted directory entry"
134 " in block %lu of inode %llu\n", block,
135 inode->i_ino);
136 brelse(bh);
137 return -EIO;
138 }
139
140 if (first_de) {
141 isofs_normalize_block_and_offset(de,
142 &block_saved,
143 &offset_saved);
144 inode_number = isofs_get_ino(block_saved,
145 offset_saved, bufbits);
146 }
147
148 if (de->flags[-sbi->s_high_sierra] & 0x80) {
149 first_de = 0;
150 ctx->pos += de_len;
151 continue;
152 }
153 first_de = 1;
154
155 /* Handle the case of the '.' directory */
156 if (de->name_len[0] == 1 && de->name[0] == 0) {
157 if (!dir_emit_dot(file, ctx))
158 break;
159 ctx->pos += de_len;
160 continue;
161 }
162
163 len = 0;
164
165 /* Handle the case of the '..' directory */
166 if (de->name_len[0] == 1 && de->name[0] == 1) {
167 if (!dir_emit_dotdot(file, ctx))
168 break;
169 ctx->pos += de_len;
170 continue;
171 }
172
173 /* Handle everything else. Do name translation if there
174 is no Rock Ridge NM field. */
175
176 /*
177 * Do not report hidden files if so instructed, or associated
178 * files unless instructed to do so
179 */
180 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
181 (!sbi->s_showassoc &&
182 (de->flags[-sbi->s_high_sierra] & 4))) {
183 ctx->pos += de_len;
184 continue;
185 }
186
187 map = 1;
188 if (sbi->s_rock) {
189 len = get_rock_ridge_filename(de, tmpname, inode);
190 if (len != 0) { /* may be -1 */
191 p = tmpname;
192 map = 0;
193 }
194 }
195 if (map) {
196 #ifdef CONFIG_JOLIET
197 if (sbi->s_joliet_level) {
198 len = get_joliet_filename(de, tmpname, inode);
199 p = tmpname;
200 } else
201 #endif
202 if (sbi->s_mapping == 'a') {
203 len = get_acorn_filename(de, tmpname, inode);
204 p = tmpname;
205 } else
206 if (sbi->s_mapping == 'n') {
207 len = isofs_name_translate(de, tmpname, inode);
208 p = tmpname;
209 } else {
210 p = de->name;
211 len = de->name_len[0];
212 }
213 }
214 if (len > 0) {
215 if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
216 break;
217 }
218 ctx->pos += de_len;
219 }
220 if (bh)
221 brelse(bh);
222 return 0;
223 }
224
225 /*
226 * Handle allocation of temporary space for name translation and
227 * handling split directory entries.. The real work is done by
228 * "do_isofs_readdir()".
229 */
isofs_readdir(struct file * file,struct dir_context * ctx)230 static int isofs_readdir(struct file *file, struct dir_context *ctx)
231 {
232 int result;
233 char *tmpname;
234 struct inode *inode = file_inode(file);
235
236 tmpname = kmalloc(1024, GFP_KERNEL);
237 if (tmpname == NULL)
238 return -ENOMEM;
239
240 result = do_isofs_readdir(inode, file, ctx, tmpname);
241
242 kfree(tmpname);
243 return result;
244 }
245
isofs_fileattr_get(struct dentry * dentry,struct file_kattr * fa)246 int isofs_fileattr_get(struct dentry *dentry, struct file_kattr *fa)
247 {
248 struct isofs_sb_info *sbi = ISOFS_SB(dentry->d_sb);
249
250 if (sbi->s_check == 'r') {
251 fa->fsx_xflags |= FS_XFLAG_CASEFOLD;
252 fa->flags |= FS_CASEFOLD_FL;
253 }
254 if (!sbi->s_joliet_level && !sbi->s_rock &&
255 (sbi->s_mapping == 'n' || sbi->s_mapping == 'a'))
256 fa->fsx_xflags |= FS_XFLAG_CASENONPRESERVING;
257 return 0;
258 }
259
260 const struct file_operations isofs_dir_operations =
261 {
262 .llseek = generic_file_llseek,
263 .read = generic_read_dir,
264 .iterate_shared = isofs_readdir,
265 .setlease = generic_setlease,
266 };
267
268 /*
269 * directories can handle most operations...
270 */
271 const struct inode_operations isofs_dir_inode_operations =
272 {
273 .lookup = isofs_lookup,
274 .fileattr_get = isofs_fileattr_get,
275 };
276
277