1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * QNX6 file system, Linux implementation.
4 *
5 * Version : 1.0.0
6 *
7 * History :
8 *
9 * 01-02-2012 by Kai Bankett (chaosman@ontika.net) : first release.
10 * 16-02-2012 pagemap extension by Al Viro
11 *
12 */
13
14 #include "qnx6.h"
15
qnx6_lfile_checksum(char * name,unsigned size)16 static unsigned qnx6_lfile_checksum(char *name, unsigned size)
17 {
18 unsigned crc = 0;
19 char *end = name + size;
20 while (name < end) {
21 crc = ((crc >> 1) + *(name++)) ^
22 ((crc & 0x00000001) ? 0x80000000 : 0);
23 }
24 return crc;
25 }
26
qnx6_get_folio(struct inode * dir,unsigned long n,struct folio ** foliop)27 static void *qnx6_get_folio(struct inode *dir, unsigned long n,
28 struct folio **foliop)
29 {
30 struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL);
31
32 if (IS_ERR(folio))
33 return folio;
34 *foliop = folio;
35 return kmap_local_folio(folio, 0);
36 }
37
last_entry(struct inode * inode,unsigned long page_nr)38 static unsigned last_entry(struct inode *inode, unsigned long page_nr)
39 {
40 unsigned long last_byte = inode->i_size;
41 last_byte -= page_nr << PAGE_SHIFT;
42 if (last_byte > PAGE_SIZE)
43 last_byte = PAGE_SIZE;
44 return last_byte / QNX6_DIR_ENTRY_SIZE;
45 }
46
qnx6_longname(struct super_block * sb,struct qnx6_long_dir_entry * de,struct folio ** foliop)47 static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
48 struct qnx6_long_dir_entry *de,
49 struct folio **foliop)
50 {
51 struct qnx6_sb_info *sbi = QNX6_SB(sb);
52 u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
53 u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
54 u32 offs;
55 struct address_space *mapping = sbi->longfile->i_mapping;
56 struct folio *folio = read_mapping_folio(mapping, n, NULL);
57
58 if (IS_ERR(folio))
59 return ERR_CAST(folio);
60 offs = offset_in_folio(folio, s << sb->s_blocksize_bits);
61 *foliop = folio;
62 return kmap_local_folio(folio, offs);
63 }
64
qnx6_dir_longfilename(struct inode * inode,struct qnx6_long_dir_entry * de,struct dir_context * ctx,unsigned de_inode)65 static int qnx6_dir_longfilename(struct inode *inode,
66 struct qnx6_long_dir_entry *de,
67 struct dir_context *ctx,
68 unsigned de_inode)
69 {
70 struct qnx6_long_filename *lf;
71 struct super_block *s = inode->i_sb;
72 struct qnx6_sb_info *sbi = QNX6_SB(s);
73 struct folio *folio;
74 int lf_size;
75
76 if (de->de_size != 0xff) {
77 /* error - long filename entries always have size 0xff
78 in direntry */
79 pr_err("invalid direntry size (%i).\n", de->de_size);
80 return 0;
81 }
82 lf = qnx6_longname(s, de, &folio);
83 if (IS_ERR(lf)) {
84 pr_err("Error reading longname\n");
85 return 0;
86 }
87
88 lf_size = fs16_to_cpu(sbi, lf->lf_size);
89
90 if (lf_size > QNX6_LONG_NAME_MAX) {
91 pr_debug("file %s\n", lf->lf_fname);
92 pr_err("Filename too long (%i)\n", lf_size);
93 folio_release_kmap(folio, lf);
94 return 0;
95 }
96
97 /* calc & validate longfilename checksum
98 mmi 3g filesystem does not have that checksum */
99 if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
100 qnx6_lfile_checksum(lf->lf_fname, lf_size))
101 pr_info("long filename checksum error.\n");
102
103 pr_debug("qnx6_readdir:%.*s inode:%u\n",
104 lf_size, lf->lf_fname, de_inode);
105 if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
106 folio_release_kmap(folio, lf);
107 return 0;
108 }
109
110 folio_release_kmap(folio, lf);
111 /* success */
112 return 1;
113 }
114
qnx6_readdir(struct file * file,struct dir_context * ctx)115 static int qnx6_readdir(struct file *file, struct dir_context *ctx)
116 {
117 struct inode *inode = file_inode(file);
118 struct super_block *s = inode->i_sb;
119 struct qnx6_sb_info *sbi = QNX6_SB(s);
120 loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
121 unsigned long npages = dir_pages(inode);
122 unsigned long n = pos >> PAGE_SHIFT;
123 unsigned offset = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
124 bool done = false;
125
126 ctx->pos = pos;
127 if (ctx->pos >= inode->i_size)
128 return 0;
129
130 for ( ; !done && n < npages; n++, offset = 0) {
131 struct qnx6_dir_entry *de;
132 struct folio *folio;
133 char *kaddr = qnx6_get_folio(inode, n, &folio);
134 char *limit;
135
136 if (IS_ERR(kaddr)) {
137 pr_err("%s(): read failed\n", __func__);
138 ctx->pos = (n + 1) << PAGE_SHIFT;
139 return PTR_ERR(kaddr);
140 }
141 de = (struct qnx6_dir_entry *)(kaddr + offset);
142 limit = kaddr + last_entry(inode, n);
143 for (; (char *)de < limit; de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) {
144 int size = de->de_size;
145 u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
146
147 if (!no_inode || !size)
148 continue;
149
150 if (size > QNX6_SHORT_NAME_MAX) {
151 /* long filename detected
152 get the filename from long filename
153 structure / block */
154 if (!qnx6_dir_longfilename(inode,
155 (struct qnx6_long_dir_entry *)de,
156 ctx, no_inode)) {
157 done = true;
158 break;
159 }
160 } else {
161 pr_debug("%s():%.*s inode:%u\n",
162 __func__, size, de->de_fname,
163 no_inode);
164 if (!dir_emit(ctx, de->de_fname, size,
165 no_inode, DT_UNKNOWN)) {
166 done = true;
167 break;
168 }
169 }
170 }
171 folio_release_kmap(folio, kaddr);
172 }
173 return 0;
174 }
175
176 /*
177 * check if the long filename is correct.
178 */
qnx6_long_match(int len,const char * name,struct qnx6_long_dir_entry * de,struct inode * dir)179 static unsigned qnx6_long_match(int len, const char *name,
180 struct qnx6_long_dir_entry *de, struct inode *dir)
181 {
182 struct super_block *s = dir->i_sb;
183 struct qnx6_sb_info *sbi = QNX6_SB(s);
184 struct folio *folio;
185 int thislen;
186 struct qnx6_long_filename *lf = qnx6_longname(s, de, &folio);
187
188 if (IS_ERR(lf))
189 return 0;
190
191 thislen = fs16_to_cpu(sbi, lf->lf_size);
192 if (len != thislen) {
193 folio_release_kmap(folio, lf);
194 return 0;
195 }
196 if (memcmp(name, lf->lf_fname, len) == 0) {
197 folio_release_kmap(folio, lf);
198 return fs32_to_cpu(sbi, de->de_inode);
199 }
200 folio_release_kmap(folio, lf);
201 return 0;
202 }
203
204 /*
205 * check if the filename is correct.
206 */
qnx6_match(struct super_block * s,int len,const char * name,struct qnx6_dir_entry * de)207 static unsigned qnx6_match(struct super_block *s, int len, const char *name,
208 struct qnx6_dir_entry *de)
209 {
210 struct qnx6_sb_info *sbi = QNX6_SB(s);
211 if (memcmp(name, de->de_fname, len) == 0)
212 return fs32_to_cpu(sbi, de->de_inode);
213 return 0;
214 }
215
216
qnx6_find_ino(int len,struct inode * dir,const char * name)217 unsigned qnx6_find_ino(int len, struct inode *dir, const char *name)
218 {
219 struct super_block *s = dir->i_sb;
220 struct qnx6_inode_info *ei = QNX6_I(dir);
221 struct folio *folio;
222 unsigned long start, n;
223 unsigned long npages = dir_pages(dir);
224 unsigned ino;
225 struct qnx6_dir_entry *de;
226 struct qnx6_long_dir_entry *lde;
227
228 if (npages == 0)
229 return 0;
230 start = ei->i_dir_start_lookup;
231 if (start >= npages)
232 start = 0;
233 n = start;
234
235 do {
236 de = qnx6_get_folio(dir, n, &folio);
237 if (!IS_ERR(de)) {
238 int limit = last_entry(dir, n);
239 int i;
240
241 for (i = 0; i < limit; i++, de++) {
242 if (len <= QNX6_SHORT_NAME_MAX) {
243 /* short filename */
244 if (len != de->de_size)
245 continue;
246 ino = qnx6_match(s, len, name, de);
247 if (ino)
248 goto found;
249 } else if (de->de_size == 0xff) {
250 /* deal with long filename */
251 lde = (struct qnx6_long_dir_entry *)de;
252 ino = qnx6_long_match(len,
253 name, lde, dir);
254 if (ino)
255 goto found;
256 } else
257 pr_err("undefined filename size in inode.\n");
258 }
259 folio_release_kmap(folio, de - i);
260 }
261
262 if (++n >= npages)
263 n = 0;
264 } while (n != start);
265 return 0;
266
267 found:
268 ei->i_dir_start_lookup = n;
269 folio_release_kmap(folio, de);
270 return ino;
271 }
272
273 const struct file_operations qnx6_dir_operations = {
274 .llseek = generic_file_llseek,
275 .read = generic_read_dir,
276 .iterate_shared = qnx6_readdir,
277 .fsync = generic_file_fsync,
278 };
279
280 const struct inode_operations qnx6_dir_inode_operations = {
281 .lookup = qnx6_lookup,
282 };
283