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 "isofs.h"
16
17 int isofs_name_translate(struct iso_directory_record *de, char *new, struct inode *inode)
18 {
19 char * old = de->name;
20 int len = de->name_len[0];
21 int i;
22
23 for (i = 0; i < len; i++) {
24 unsigned char c = old[i];
25 if (!c)
26 break;
27
28 if (c >= 'A' && c <= 'Z')
29 c |= 0x20; /* lower case */
30
31 /* Drop trailing '.;1' (ISO 9660:1988 7.5.1 requires period) */
32 if (c == '.' && i == len - 3 && old[i + 1] == ';' && old[i + 2] == '1')
33 break;
34
35 /* Drop trailing ';1' */
36 if (c == ';' && i == len - 2 && old[i + 1] == '1')
37 break;
38
39 /* Convert remaining ';' to '.' */
40 /* Also '/' to '.' (broken Acorn-generated ISO9660 images) */
41 if (c == ';' || c == '/')
42 c = '.';
43
44 new[i] = c;
45 }
46 return i;
47 }
48
49 /* Acorn extensions written by Matthew Wilcox <willy@infradead.org> 1998 */
50 int get_acorn_filename(struct iso_directory_record *de,
51 char *retname, struct inode *inode)
52 {
53 int std;
54 unsigned char *chr;
55 int retnamlen = isofs_name_translate(de, retname, inode);
56
57 if (retnamlen == 0)
58 return 0;
59 std = sizeof(struct iso_directory_record) + de->name_len[0];
60 if (std & 1)
61 std++;
62 if (de->length[0] - std != 32)
63 return retnamlen;
64 chr = ((unsigned char *) de) + std;
65 if (strncmp(chr, "ARCHIMEDES", 10))
66 return retnamlen;
67 if ((*retname == '_') && ((chr[19] & 1) == 1))
68 *retname = '!';
69 if (((de->flags[0] & 2) == 0) && (chr[13] == 0xff)
70 && ((chr[12] & 0xf0) == 0xf0)) {
71 retname[retnamlen] = ',';
72 sprintf(retname+retnamlen+1, "%3.3x",
73 ((chr[12] & 0xf) << 8) | chr[11]);
74 retnamlen += 4;
75 }
76 return retnamlen;
77 }
78
79 /*
80 * This should _really_ be cleaned up some day..
81 */
82 static int do_isofs_readdir(struct inode *inode, struct file *file,
83 struct dir_context *ctx,
84 char *tmpname, struct iso_directory_record *tmpde)
85 {
86 unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
87 unsigned char bufbits = ISOFS_BUFFER_BITS(inode);
88 unsigned long block, offset, block_saved, offset_saved;
89 unsigned long inode_number = 0; /* Quiet GCC */
90 struct buffer_head *bh = NULL;
91 int len;
92 int map;
93 int first_de = 1;
94 char *p = NULL; /* Quiet GCC */
95 struct iso_directory_record *de;
96 struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
97
98 offset = ctx->pos & (bufsize - 1);
99 block = ctx->pos >> bufbits;
100
101 while (ctx->pos < inode->i_size) {
102 int de_len;
103
104 if (!bh) {
105 bh = isofs_bread(inode, block);
106 if (!bh)
107 return 0;
108 }
109
110 de = (struct iso_directory_record *) (bh->b_data + offset);
111
112 de_len = *(unsigned char *)de;
113
114 /*
115 * If the length byte is zero, we should move on to the next
116 * CDROM sector. If we are at the end of the directory, we
117 * kick out of the while loop.
118 */
119
120 if (de_len == 0) {
121 brelse(bh);
122 bh = NULL;
123 ctx->pos = (ctx->pos + ISOFS_BLOCK_SIZE) & ~(ISOFS_BLOCK_SIZE - 1);
124 block = ctx->pos >> bufbits;
125 offset = 0;
126 continue;
127 }
128
129 block_saved = block;
130 offset_saved = offset;
131 offset += de_len;
132
133 /* Make sure we have a full directory entry */
134 if (offset >= bufsize) {
135 int slop = bufsize - offset + de_len;
136 memcpy(tmpde, de, slop);
137 offset &= bufsize - 1;
138 block++;
139 brelse(bh);
140 bh = NULL;
141 if (offset) {
142 bh = isofs_bread(inode, block);
143 if (!bh)
144 return 0;
145 memcpy((void *) tmpde + slop, bh->b_data, offset);
146 }
147 de = tmpde;
148 }
149 /* Basic sanity check, whether name doesn't exceed dir entry */
150 if (de_len < de->name_len[0] +
151 sizeof(struct iso_directory_record)) {
152 printk(KERN_NOTICE "iso9660: Corrupted directory entry"
153 " in block %lu of inode %lu\n", block,
154 inode->i_ino);
155 brelse(bh);
156 return -EIO;
157 }
158
159 if (first_de) {
160 isofs_normalize_block_and_offset(de,
161 &block_saved,
162 &offset_saved);
163 inode_number = isofs_get_ino(block_saved,
164 offset_saved, bufbits);
165 }
166
167 if (de->flags[-sbi->s_high_sierra] & 0x80) {
168 first_de = 0;
169 ctx->pos += de_len;
170 continue;
171 }
172 first_de = 1;
173
174 /* Handle the case of the '.' directory */
175 if (de->name_len[0] == 1 && de->name[0] == 0) {
176 if (!dir_emit_dot(file, ctx))
177 break;
178 ctx->pos += de_len;
179 continue;
180 }
181
182 len = 0;
183
184 /* Handle the case of the '..' directory */
185 if (de->name_len[0] == 1 && de->name[0] == 1) {
186 if (!dir_emit_dotdot(file, ctx))
187 break;
188 ctx->pos += de_len;
189 continue;
190 }
191
192 /* Handle everything else. Do name translation if there
193 is no Rock Ridge NM field. */
194
195 /*
196 * Do not report hidden files if so instructed, or associated
197 * files unless instructed to do so
198 */
199 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
200 (!sbi->s_showassoc &&
201 (de->flags[-sbi->s_high_sierra] & 4))) {
202 ctx->pos += de_len;
203 continue;
204 }
205
206 map = 1;
207 if (sbi->s_rock) {
208 len = get_rock_ridge_filename(de, tmpname, inode);
209 if (len != 0) { /* may be -1 */
210 p = tmpname;
211 map = 0;
212 }
213 }
214 if (map) {
215 #ifdef CONFIG_JOLIET
216 if (sbi->s_joliet_level) {
217 len = get_joliet_filename(de, tmpname, inode);
218 p = tmpname;
219 } else
220 #endif
221 if (sbi->s_mapping == 'a') {
222 len = get_acorn_filename(de, tmpname, inode);
223 p = tmpname;
224 } else
225 if (sbi->s_mapping == 'n') {
226 len = isofs_name_translate(de, tmpname, inode);
227 p = tmpname;
228 } else {
229 p = de->name;
230 len = de->name_len[0];
231 }
232 }
233 if (len > 0) {
234 if (!dir_emit(ctx, p, len, inode_number, DT_UNKNOWN))
235 break;
236 }
237 ctx->pos += de_len;
238 }
239 if (bh)
240 brelse(bh);
241 return 0;
242 }
243
244 /*
245 * Handle allocation of temporary space for name translation and
246 * handling split directory entries.. The real work is done by
247 * "do_isofs_readdir()".
248 */
249 static int isofs_readdir(struct file *file, struct dir_context *ctx)
250 {
251 int result;
252 char *tmpname;
253 struct iso_directory_record *tmpde;
254 struct inode *inode = file_inode(file);
255
256 tmpname = (char *)__get_free_page(GFP_KERNEL);
257 if (tmpname == NULL)
258 return -ENOMEM;
259
260 tmpde = (struct iso_directory_record *) (tmpname+1024);
261
262 result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);
263
264 free_page((unsigned long) tmpname);
265 return result;
266 }
267
268 const struct file_operations isofs_dir_operations =
269 {
270 .llseek = generic_file_llseek,
271 .read = generic_read_dir,
272 .iterate_shared = isofs_readdir,
273 };
274
275 /*
276 * directories can handle most operations...
277 */
278 const struct inode_operations isofs_dir_inode_operations =
279 {
280 .lookup = isofs_lookup,
281 };
282
283
284
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