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, new: 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(buf: retname+retnamlen+1, fmt: "%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(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: &block_saved, |
162 | offset: &offset_saved); |
163 | inode_number = isofs_get_ino(block: block_saved, |
164 | offset: 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, retname: tmpname, inode); |
223 | p = tmpname; |
224 | } else |
225 | if (sbi->s_mapping == 'n') { |
226 | len = isofs_name_translate(de, new: 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, name: p, namelen: len, ino: 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(f: 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 | |