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_page(struct inode * dir,unsigned long n)27 static struct page *qnx6_get_page(struct inode *dir, unsigned long n)
28 {
29 struct address_space *mapping = dir->i_mapping;
30 struct page *page = read_mapping_page(mapping, n, NULL);
31 if (!IS_ERR(page))
32 kmap(page);
33 return page;
34 }
35
last_entry(struct inode * inode,unsigned long page_nr)36 static unsigned last_entry(struct inode *inode, unsigned long page_nr)
37 {
38 unsigned long last_byte = inode->i_size;
39 last_byte -= page_nr << PAGE_SHIFT;
40 if (last_byte > PAGE_SIZE)
41 last_byte = PAGE_SIZE;
42 return last_byte / QNX6_DIR_ENTRY_SIZE;
43 }
44
qnx6_longname(struct super_block * sb,struct qnx6_long_dir_entry * de,struct page ** p)45 static struct qnx6_long_filename *qnx6_longname(struct super_block *sb,
46 struct qnx6_long_dir_entry *de,
47 struct page **p)
48 {
49 struct qnx6_sb_info *sbi = QNX6_SB(sb);
50 u32 s = fs32_to_cpu(sbi, de->de_long_inode); /* in block units */
51 u32 n = s >> (PAGE_SHIFT - sb->s_blocksize_bits); /* in pages */
52 /* within page */
53 u32 offs = (s << sb->s_blocksize_bits) & ~PAGE_MASK;
54 struct address_space *mapping = sbi->longfile->i_mapping;
55 struct page *page = read_mapping_page(mapping, n, NULL);
56 if (IS_ERR(page))
57 return ERR_CAST(page);
58 kmap(*p = page);
59 return (struct qnx6_long_filename *)(page_address(page) + offs);
60 }
61
qnx6_dir_longfilename(struct inode * inode,struct qnx6_long_dir_entry * de,struct dir_context * ctx,unsigned de_inode)62 static int qnx6_dir_longfilename(struct inode *inode,
63 struct qnx6_long_dir_entry *de,
64 struct dir_context *ctx,
65 unsigned de_inode)
66 {
67 struct qnx6_long_filename *lf;
68 struct super_block *s = inode->i_sb;
69 struct qnx6_sb_info *sbi = QNX6_SB(s);
70 struct page *page;
71 int lf_size;
72
73 if (de->de_size != 0xff) {
74 /* error - long filename entries always have size 0xff
75 in direntry */
76 pr_err("invalid direntry size (%i).\n", de->de_size);
77 return 0;
78 }
79 lf = qnx6_longname(s, de, &page);
80 if (IS_ERR(lf)) {
81 pr_err("Error reading longname\n");
82 return 0;
83 }
84
85 lf_size = fs16_to_cpu(sbi, lf->lf_size);
86
87 if (lf_size > QNX6_LONG_NAME_MAX) {
88 pr_debug("file %s\n", lf->lf_fname);
89 pr_err("Filename too long (%i)\n", lf_size);
90 qnx6_put_page(page);
91 return 0;
92 }
93
94 /* calc & validate longfilename checksum
95 mmi 3g filesystem does not have that checksum */
96 if (!test_opt(s, MMI_FS) && fs32_to_cpu(sbi, de->de_checksum) !=
97 qnx6_lfile_checksum(lf->lf_fname, lf_size))
98 pr_info("long filename checksum error.\n");
99
100 pr_debug("qnx6_readdir:%.*s inode:%u\n",
101 lf_size, lf->lf_fname, de_inode);
102 if (!dir_emit(ctx, lf->lf_fname, lf_size, de_inode, DT_UNKNOWN)) {
103 qnx6_put_page(page);
104 return 0;
105 }
106
107 qnx6_put_page(page);
108 /* success */
109 return 1;
110 }
111
qnx6_readdir(struct file * file,struct dir_context * ctx)112 static int qnx6_readdir(struct file *file, struct dir_context *ctx)
113 {
114 struct inode *inode = file_inode(file);
115 struct super_block *s = inode->i_sb;
116 struct qnx6_sb_info *sbi = QNX6_SB(s);
117 loff_t pos = ctx->pos & ~(QNX6_DIR_ENTRY_SIZE - 1);
118 unsigned long npages = dir_pages(inode);
119 unsigned long n = pos >> PAGE_SHIFT;
120 unsigned start = (pos & ~PAGE_MASK) / QNX6_DIR_ENTRY_SIZE;
121 bool done = false;
122
123 ctx->pos = pos;
124 if (ctx->pos >= inode->i_size)
125 return 0;
126
127 for ( ; !done && n < npages; n++, start = 0) {
128 struct page *page = qnx6_get_page(inode, n);
129 int limit = last_entry(inode, n);
130 struct qnx6_dir_entry *de;
131 int i = start;
132
133 if (IS_ERR(page)) {
134 pr_err("%s(): read failed\n", __func__);
135 ctx->pos = (n + 1) << PAGE_SHIFT;
136 return PTR_ERR(page);
137 }
138 de = ((struct qnx6_dir_entry *)page_address(page)) + start;
139 for (; i < limit; i++, de++, ctx->pos += QNX6_DIR_ENTRY_SIZE) {
140 int size = de->de_size;
141 u32 no_inode = fs32_to_cpu(sbi, de->de_inode);
142
143 if (!no_inode || !size)
144 continue;
145
146 if (size > QNX6_SHORT_NAME_MAX) {
147 /* long filename detected
148 get the filename from long filename
149 structure / block */
150 if (!qnx6_dir_longfilename(inode,
151 (struct qnx6_long_dir_entry *)de,
152 ctx, no_inode)) {
153 done = true;
154 break;
155 }
156 } else {
157 pr_debug("%s():%.*s inode:%u\n",
158 __func__, size, de->de_fname,
159 no_inode);
160 if (!dir_emit(ctx, de->de_fname, size,
161 no_inode, DT_UNKNOWN)) {
162 done = true;
163 break;
164 }
165 }
166 }
167 qnx6_put_page(page);
168 }
169 return 0;
170 }
171
172 /*
173 * check if the long filename is correct.
174 */
qnx6_long_match(int len,const char * name,struct qnx6_long_dir_entry * de,struct inode * dir)175 static unsigned qnx6_long_match(int len, const char *name,
176 struct qnx6_long_dir_entry *de, struct inode *dir)
177 {
178 struct super_block *s = dir->i_sb;
179 struct qnx6_sb_info *sbi = QNX6_SB(s);
180 struct page *page;
181 int thislen;
182 struct qnx6_long_filename *lf = qnx6_longname(s, de, &page);
183
184 if (IS_ERR(lf))
185 return 0;
186
187 thislen = fs16_to_cpu(sbi, lf->lf_size);
188 if (len != thislen) {
189 qnx6_put_page(page);
190 return 0;
191 }
192 if (memcmp(name, lf->lf_fname, len) == 0) {
193 qnx6_put_page(page);
194 return fs32_to_cpu(sbi, de->de_inode);
195 }
196 qnx6_put_page(page);
197 return 0;
198 }
199
200 /*
201 * check if the filename is correct.
202 */
qnx6_match(struct super_block * s,int len,const char * name,struct qnx6_dir_entry * de)203 static unsigned qnx6_match(struct super_block *s, int len, const char *name,
204 struct qnx6_dir_entry *de)
205 {
206 struct qnx6_sb_info *sbi = QNX6_SB(s);
207 if (memcmp(name, de->de_fname, len) == 0)
208 return fs32_to_cpu(sbi, de->de_inode);
209 return 0;
210 }
211
212
qnx6_find_entry(int len,struct inode * dir,const char * name,struct page ** res_page)213 unsigned qnx6_find_entry(int len, struct inode *dir, const char *name,
214 struct page **res_page)
215 {
216 struct super_block *s = dir->i_sb;
217 struct qnx6_inode_info *ei = QNX6_I(dir);
218 struct page *page = NULL;
219 unsigned long start, n;
220 unsigned long npages = dir_pages(dir);
221 unsigned ino;
222 struct qnx6_dir_entry *de;
223 struct qnx6_long_dir_entry *lde;
224
225 *res_page = NULL;
226
227 if (npages == 0)
228 return 0;
229 start = ei->i_dir_start_lookup;
230 if (start >= npages)
231 start = 0;
232 n = start;
233
234 do {
235 page = qnx6_get_page(dir, n);
236 if (!IS_ERR(page)) {
237 int limit = last_entry(dir, n);
238 int i;
239
240 de = (struct qnx6_dir_entry *)page_address(page);
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 qnx6_put_page(page);
260 }
261
262 if (++n >= npages)
263 n = 0;
264 } while (n != start);
265 return 0;
266
267 found:
268 *res_page = page;
269 ei->i_dir_start_lookup = n;
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