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 <linux/filelock.h>
15 #include "qnx6.h"
16
qnx6_lfile_checksum(char * name,unsigned size)17 static unsigned qnx6_lfile_checksum(char *name, unsigned size)
18 {
19 unsigned crc = 0;
20 char *end = name + size;
21 while (name < end) {
22 crc = ((crc >> 1) + *(name++)) ^
23 ((crc & 0x00000001) ? 0x80000000 : 0);
24 }
25 return crc;
26 }
27
qnx6_get_folio(struct inode * dir,unsigned long n,struct folio ** foliop)28 static void *qnx6_get_folio(struct inode *dir, unsigned long n,
29 struct folio **foliop)
30 {
31 struct folio *folio = read_mapping_folio(dir->i_mapping, n, NULL);
32
33 if (IS_ERR(folio))
34 return folio;
35 *foliop = folio;
36 return kmap_local_folio(folio, 0);
37 }
38
last_entry(struct inode * inode,unsigned long page_nr)39 static unsigned last_entry(struct inode *inode, unsigned long page_nr)
40 {
41 unsigned long last_byte = inode->i_size;
42 last_byte -= page_nr << PAGE_SHIFT;
43 if (last_byte > PAGE_SIZE)
44 last_byte = PAGE_SIZE;
45 return last_byte / QNX6_DIR_ENTRY_SIZE;
46 }
47
qnx6_longname(struct super_block * sb,struct qnx6_long_dir_entry * de,struct folio ** foliop)48 static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
49 struct qnx6_long_dir_entry *de,
50 struct folio **foliop)
51 {
52 struct qnx6_sb_info *sbi = QNX6_SB(sb);
53 u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
54 u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
55 u32 offs;
56 struct address_space *mapping = sbi->longfile->i_mapping;
57 struct folio *folio = read_mapping_folio(mapping, n, NULL);
58
59 if (IS_ERR(folio))
60 return ERR_CAST(folio);
61 offs = offset_in_folio(folio, s << sb->s_blocksize_bits);
62 *foliop = folio;
63 return kmap_local_folio(folio, offs);
64 }
65
qnx6_dir_longfilename(struct inode * inode,struct qnx6_long_dir_entry * de,struct dir_context * ctx,unsigned de_inode)66 static int qnx6_dir_longfilename(struct inode *inode,
67 struct qnx6_long_dir_entry *de,
68 struct dir_context *ctx,
69 unsigned de_inode)
70 {
71 struct qnx6_long_filename *lf;
72 struct super_block *s = inode->i_sb;
73 struct qnx6_sb_info *sbi = QNX6_SB(s);
74 struct folio *folio;
75 int lf_size;
76
77 if (de->de_size != 0xff) {
78 /* error - long filename entries always have size 0xff
79 in direntry */
80 pr_err("invalid direntry size (%i).\n", de->de_size);
81 return 0;
82 }
83 lf = qnx6_longname(s, de, &folio);
84 if (IS_ERR(lf)) {
85 pr_err("Error reading longname\n");
86 return 0;
87 }
88
89 lf_size = fs16_to_cpu(sbi, lf->lf_size);
90
91 if (lf_size > QNX6_LONG_NAME_MAX) {
92 pr_debug("file %s\n", lf->lf_fname);
93 pr_err("Filename too long (%i)\n", lf_size);
94 folio_release_kmap(folio, lf);
95 return 0;
96 }
97
98 /* calc & validate longfilename checksum
99 mmi 3g filesystem does not have that checksum */
100 if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
101 qnx6_lfile_checksum(lf->lf_fname, lf_size))
102 pr_info("long filename checksum error.\n");
103
104 pr_debug("qnx6_readdir:%.*s inode:%u\n",
105 lf_size, lf->lf_fname, de_inode);
106 if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
107 folio_release_kmap(folio, lf);
108 return 0;
109 }
110
111 folio_release_kmap(folio, lf);
112 /* success */
113 return 1;
114 }
115
qnx6_readdir(struct file * file,struct dir_context * ctx)116 static int qnx6_readdir(struct file *file, struct dir_context *ctx)
117 {
118 struct inode *inode = file_inode(file);
119 struct super_block *s = inode->i_sb;
120 struct qnx6_sb_info *sbi = QNX6_SB(s);
121 loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
122 unsigned long npages = dir_pages(inode);
123 unsigned long n = pos >> PAGE_SHIFT;
124 unsigned offset = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
125 bool done = false;
126
127 ctx->pos = pos;
128 if (ctx->pos >= inode->i_size)
129 return 0;
130
131 for ( ; !done && n < npages; n++, offset = 0) {
132 struct qnx6_dir_entry *de;
133 struct folio *folio;
134 char *kaddr = qnx6_get_folio(inode, n, &folio);
135 struct qnx6_dir_entry *limit;
136
137 if (IS_ERR(kaddr)) {
138 pr_err("%s(): read failed\n", __func__);
139 ctx->pos = (n + 1) << PAGE_SHIFT;
140 return PTR_ERR(kaddr);
141 }
142 de = (struct qnx6_dir_entry *)kaddr + offset;
143 limit = (struct qnx6_dir_entry *)kaddr + last_entry(inode, n);
144 for (; de < limit; de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) {
145 int size = de->de_size;
146 u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
147
148 if (!no_inode || !size)
149 continue;
150
151 if (size > QNX6_SHORT_NAME_MAX) {
152 /* long filename detected
153 get the filename from long filename
154 structure / block */
155 if (!qnx6_dir_longfilename(inode,
156 (struct qnx6_long_dir_entry *)de,
157 ctx, no_inode)) {
158 done = true;
159 break;
160 }
161 } else {
162 pr_debug("%s():%.*s inode:%u\n",
163 __func__, size, de->de_fname,
164 no_inode);
165 if (!dir_emit(ctx, de->de_fname, size,
166 no_inode, DT_UNKNOWN)) {
167 done = true;
168 break;
169 }
170 }
171 }
172 folio_release_kmap(folio, kaddr);
173 }
174 return 0;
175 }
176
177 /*
178 * check if the long filename is correct.
179 */
qnx6_long_match(int len,const char * name,struct qnx6_long_dir_entry * de,struct inode * dir)180 static unsigned qnx6_long_match(int len, const char *name,
181 struct qnx6_long_dir_entry *de, struct inode *dir)
182 {
183 struct super_block *s = dir->i_sb;
184 struct qnx6_sb_info *sbi = QNX6_SB(s);
185 struct folio *folio;
186 int thislen;
187 struct qnx6_long_filename *lf = qnx6_longname(s, de, &folio);
188
189 if (IS_ERR(lf))
190 return 0;
191
192 thislen = fs16_to_cpu(sbi, lf->lf_size);
193 if (len != thislen) {
194 folio_release_kmap(folio, lf);
195 return 0;
196 }
197 if (memcmp(name, lf->lf_fname, len) == 0) {
198 folio_release_kmap(folio, lf);
199 return fs32_to_cpu(sbi, de->de_inode);
200 }
201 folio_release_kmap(folio, lf);
202 return 0;
203 }
204
205 /*
206 * check if the filename is correct.
207 */
qnx6_match(struct super_block * s,int len,const char * name,struct qnx6_dir_entry * de)208 static unsigned qnx6_match(struct super_block *s, int len, const char *name,
209 struct qnx6_dir_entry *de)
210 {
211 struct qnx6_sb_info *sbi = QNX6_SB(s);
212 if (memcmp(name, de->de_fname, len) == 0)
213 return fs32_to_cpu(sbi, de->de_inode);
214 return 0;
215 }
216
217
qnx6_find_ino(int len,struct inode * dir,const char * name)218 unsigned qnx6_find_ino(int len, struct inode *dir, const char *name)
219 {
220 struct super_block *s = dir->i_sb;
221 struct qnx6_inode_info *ei = QNX6_I(dir);
222 struct folio *folio;
223 unsigned long start, n;
224 unsigned long npages = dir_pages(dir);
225 unsigned ino;
226 struct qnx6_dir_entry *de;
227 struct qnx6_long_dir_entry *lde;
228
229 if (npages == 0)
230 return 0;
231 start = ei->i_dir_start_lookup;
232 if (start >= npages)
233 start = 0;
234 n = start;
235
236 do {
237 de = qnx6_get_folio(dir, n, &folio);
238 if (!IS_ERR(de)) {
239 int limit = last_entry(dir, n);
240 int i;
241
242 for (i = 0; i < limit; i++, de++) {
243 if (len <= QNX6_SHORT_NAME_MAX) {
244 /* short filename */
245 if (len != de->de_size)
246 continue;
247 ino = qnx6_match(s, len, name, de);
248 if (ino)
249 goto found;
250 } else if (de->de_size == 0xff) {
251 /* deal with long filename */
252 lde = (struct qnx6_long_dir_entry *)de;
253 ino = qnx6_long_match(len,
254 name, lde, dir);
255 if (ino)
256 goto found;
257 } else
258 pr_err("undefined filename size in inode.\n");
259 }
260 folio_release_kmap(folio, de - i);
261 }
262
263 if (++n >= npages)
264 n = 0;
265 } while (n != start);
266 return 0;
267
268 found:
269 ei->i_dir_start_lookup = n;
270 folio_release_kmap(folio, de);
271 return ino;
272 }
273
274 const struct file_operations qnx6_dir_operations = {
275 .llseek = generic_file_llseek,
276 .read = generic_read_dir,
277 .iterate_shared = qnx6_readdir,
278 .fsync = simple_fsync,
279 .setlease = generic_setlease,
280 };
281
282 const struct inode_operations qnx6_dir_inode_operations = {
283 .lookup = qnx6_lookup,
284 };
285