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
17int 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 */
50int 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 */
82static 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(to: tmpde, from: de, len: 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(to: (void *) tmpde + slop, from: bh->b_data, len: offset);
146 }
147 de = tmpde;
148 }
149 /* Basic sanity check, whether name doesn't exceed dir entry */
150 if (de_len < sizeof(struct iso_directory_record) ||
151 de_len < de->name_len[0] +
152 sizeof(struct iso_directory_record)) {
153 printk(KERN_NOTICE "iso9660: Corrupted directory entry"
154 " in block %lu of inode %lu\n", block,
155 inode->i_ino);
156 brelse(bh);
157 return -EIO;
158 }
159
160 if (first_de) {
161 isofs_normalize_block_and_offset(de,
162 block: &block_saved,
163 offset: &offset_saved);
164 inode_number = isofs_get_ino(block: block_saved,
165 offset: offset_saved, bufbits);
166 }
167
168 if (de->flags[-sbi->s_high_sierra] & 0x80) {
169 first_de = 0;
170 ctx->pos += de_len;
171 continue;
172 }
173 first_de = 1;
174
175 /* Handle the case of the '.' directory */
176 if (de->name_len[0] == 1 && de->name[0] == 0) {
177 if (!dir_emit_dot(file, ctx))
178 break;
179 ctx->pos += de_len;
180 continue;
181 }
182
183 len = 0;
184
185 /* Handle the case of the '..' directory */
186 if (de->name_len[0] == 1 && de->name[0] == 1) {
187 if (!dir_emit_dotdot(file, ctx))
188 break;
189 ctx->pos += de_len;
190 continue;
191 }
192
193 /* Handle everything else. Do name translation if there
194 is no Rock Ridge NM field. */
195
196 /*
197 * Do not report hidden files if so instructed, or associated
198 * files unless instructed to do so
199 */
200 if ((sbi->s_hide && (de->flags[-sbi->s_high_sierra] & 1)) ||
201 (!sbi->s_showassoc &&
202 (de->flags[-sbi->s_high_sierra] & 4))) {
203 ctx->pos += de_len;
204 continue;
205 }
206
207 map = 1;
208 if (sbi->s_rock) {
209 len = get_rock_ridge_filename(de, tmpname, inode);
210 if (len != 0) { /* may be -1 */
211 p = tmpname;
212 map = 0;
213 }
214 }
215 if (map) {
216#ifdef CONFIG_JOLIET
217 if (sbi->s_joliet_level) {
218 len = get_joliet_filename(de, tmpname, inode);
219 p = tmpname;
220 } else
221#endif
222 if (sbi->s_mapping == 'a') {
223 len = get_acorn_filename(de, retname: tmpname, inode);
224 p = tmpname;
225 } else
226 if (sbi->s_mapping == 'n') {
227 len = isofs_name_translate(de, new: tmpname, inode);
228 p = tmpname;
229 } else {
230 p = de->name;
231 len = de->name_len[0];
232 }
233 }
234 if (len > 0) {
235 if (!dir_emit(ctx, name: p, namelen: len, ino: inode_number, DT_UNKNOWN))
236 break;
237 }
238 ctx->pos += de_len;
239 }
240 if (bh)
241 brelse(bh);
242 return 0;
243}
244
245/*
246 * Handle allocation of temporary space for name translation and
247 * handling split directory entries.. The real work is done by
248 * "do_isofs_readdir()".
249 */
250static int isofs_readdir(struct file *file, struct dir_context *ctx)
251{
252 int result;
253 char *tmpname;
254 struct iso_directory_record *tmpde;
255 struct inode *inode = file_inode(f: file);
256
257 tmpname = (char *)__get_free_page(GFP_KERNEL);
258 if (tmpname == NULL)
259 return -ENOMEM;
260
261 tmpde = (struct iso_directory_record *) (tmpname+1024);
262
263 result = do_isofs_readdir(inode, file, ctx, tmpname, tmpde);
264
265 free_page((unsigned long) tmpname);
266 return result;
267}
268
269const struct file_operations isofs_dir_operations =
270{
271 .llseek = generic_file_llseek,
272 .read = generic_read_dir,
273 .iterate_shared = isofs_readdir,
274};
275
276/*
277 * directories can handle most operations...
278 */
279const struct inode_operations isofs_dir_inode_operations =
280{
281 .lookup = isofs_lookup,
282};
283
284
285