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TOMOYO Linux Cross Reference
Linux/fs/affs/namei.c

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  1 /*
  2  *  linux/fs/affs/namei.c
  3  *
  4  *  (c) 1996  Hans-Joachim Widmaier - Rewritten
  5  *
  6  *  (C) 1993  Ray Burr - Modified for Amiga FFS filesystem.
  7  *
  8  *  (C) 1991  Linus Torvalds - minix filesystem
  9  */
 10 
 11 #include "affs.h"
 12 
 13 typedef int (*toupper_t)(int);
 14 
 15 static int       affs_toupper(int ch);
 16 static int       affs_hash_dentry(const struct dentry *, struct qstr *);
 17 static int       affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 18                 unsigned int len, const char *str, const struct qstr *name);
 19 static int       affs_intl_toupper(int ch);
 20 static int       affs_intl_hash_dentry(const struct dentry *, struct qstr *);
 21 static int       affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
 22                 unsigned int len, const char *str, const struct qstr *name);
 23 
 24 const struct dentry_operations affs_dentry_operations = {
 25         .d_hash         = affs_hash_dentry,
 26         .d_compare      = affs_compare_dentry,
 27 };
 28 
 29 const struct dentry_operations affs_intl_dentry_operations = {
 30         .d_hash         = affs_intl_hash_dentry,
 31         .d_compare      = affs_intl_compare_dentry,
 32 };
 33 
 34 
 35 /* Simple toupper() for DOS\1 */
 36 
 37 static int
 38 affs_toupper(int ch)
 39 {
 40         return ch >= 'a' && ch <= 'z' ? ch -= ('a' - 'A') : ch;
 41 }
 42 
 43 /* International toupper() for DOS\3 ("international") */
 44 
 45 static int
 46 affs_intl_toupper(int ch)
 47 {
 48         return (ch >= 'a' && ch <= 'z') || (ch >= 0xE0
 49                 && ch <= 0xFE && ch != 0xF7) ?
 50                 ch - ('a' - 'A') : ch;
 51 }
 52 
 53 static inline toupper_t
 54 affs_get_toupper(struct super_block *sb)
 55 {
 56         return AFFS_SB(sb)->s_flags & SF_INTL ? affs_intl_toupper : affs_toupper;
 57 }
 58 
 59 /*
 60  * Note: the dentry argument is the parent dentry.
 61  */
 62 static inline int
 63 __affs_hash_dentry(struct qstr *qstr, toupper_t toupper, bool notruncate)
 64 {
 65         const u8 *name = qstr->name;
 66         unsigned long hash;
 67         int retval;
 68         u32 len;
 69 
 70         retval = affs_check_name(qstr->name, qstr->len, notruncate);
 71         if (retval)
 72                 return retval;
 73 
 74         hash = init_name_hash();
 75         len = min(qstr->len, AFFSNAMEMAX);
 76         for (; len > 0; name++, len--)
 77                 hash = partial_name_hash(toupper(*name), hash);
 78         qstr->hash = end_name_hash(hash);
 79 
 80         return 0;
 81 }
 82 
 83 static int
 84 affs_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 85 {
 86         return __affs_hash_dentry(qstr, affs_toupper,
 87                                   affs_nofilenametruncate(dentry));
 88 
 89 }
 90 
 91 static int
 92 affs_intl_hash_dentry(const struct dentry *dentry, struct qstr *qstr)
 93 {
 94         return __affs_hash_dentry(qstr, affs_intl_toupper,
 95                                   affs_nofilenametruncate(dentry));
 96 
 97 }
 98 
 99 static inline int __affs_compare_dentry(unsigned int len,
100                 const char *str, const struct qstr *name, toupper_t toupper,
101                 bool notruncate)
102 {
103         const u8 *aname = str;
104         const u8 *bname = name->name;
105 
106         /*
107          * 'str' is the name of an already existing dentry, so the name
108          * must be valid. 'name' must be validated first.
109          */
110 
111         if (affs_check_name(name->name, name->len, notruncate))
112                 return 1;
113 
114         /*
115          * If the names are longer than the allowed 30 chars,
116          * the excess is ignored, so their length may differ.
117          */
118         if (len >= AFFSNAMEMAX) {
119                 if (name->len < AFFSNAMEMAX)
120                         return 1;
121                 len = AFFSNAMEMAX;
122         } else if (len != name->len)
123                 return 1;
124 
125         for (; len > 0; len--)
126                 if (toupper(*aname++) != toupper(*bname++))
127                         return 1;
128 
129         return 0;
130 }
131 
132 static int
133 affs_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
134                 unsigned int len, const char *str, const struct qstr *name)
135 {
136 
137         return __affs_compare_dentry(len, str, name, affs_toupper,
138                                      affs_nofilenametruncate(parent));
139 }
140 
141 static int
142 affs_intl_compare_dentry(const struct dentry *parent, const struct dentry *dentry,
143                 unsigned int len, const char *str, const struct qstr *name)
144 {
145         return __affs_compare_dentry(len, str, name, affs_intl_toupper,
146                                      affs_nofilenametruncate(parent));
147 
148 }
149 
150 /*
151  * NOTE! unlike strncmp, affs_match returns 1 for success, 0 for failure.
152  */
153 
154 static inline int
155 affs_match(struct dentry *dentry, const u8 *name2, toupper_t toupper)
156 {
157         const u8 *name = dentry->d_name.name;
158         int len = dentry->d_name.len;
159 
160         if (len >= AFFSNAMEMAX) {
161                 if (*name2 < AFFSNAMEMAX)
162                         return 0;
163                 len = AFFSNAMEMAX;
164         } else if (len != *name2)
165                 return 0;
166 
167         for (name2++; len > 0; len--)
168                 if (toupper(*name++) != toupper(*name2++))
169                         return 0;
170         return 1;
171 }
172 
173 int
174 affs_hash_name(struct super_block *sb, const u8 *name, unsigned int len)
175 {
176         toupper_t toupper = affs_get_toupper(sb);
177         u32 hash;
178 
179         hash = len = min(len, AFFSNAMEMAX);
180         for (; len > 0; len--)
181                 hash = (hash * 13 + toupper(*name++)) & 0x7ff;
182 
183         return hash % AFFS_SB(sb)->s_hashsize;
184 }
185 
186 static struct buffer_head *
187 affs_find_entry(struct inode *dir, struct dentry *dentry)
188 {
189         struct super_block *sb = dir->i_sb;
190         struct buffer_head *bh;
191         toupper_t toupper = affs_get_toupper(sb);
192         u32 key;
193 
194         pr_debug("%s(\"%pd\")\n", __func__, dentry);
195 
196         bh = affs_bread(sb, dir->i_ino);
197         if (!bh)
198                 return ERR_PTR(-EIO);
199 
200         key = be32_to_cpu(AFFS_HEAD(bh)->table[affs_hash_name(sb, dentry->d_name.name, dentry->d_name.len)]);
201 
202         for (;;) {
203                 affs_brelse(bh);
204                 if (key == 0)
205                         return NULL;
206                 bh = affs_bread(sb, key);
207                 if (!bh)
208                         return ERR_PTR(-EIO);
209                 if (affs_match(dentry, AFFS_TAIL(sb, bh)->name, toupper))
210                         return bh;
211                 key = be32_to_cpu(AFFS_TAIL(sb, bh)->hash_chain);
212         }
213 }
214 
215 struct dentry *
216 affs_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags)
217 {
218         struct super_block *sb = dir->i_sb;
219         struct buffer_head *bh;
220         struct inode *inode = NULL;
221 
222         pr_debug("%s(\"%pd\")\n", __func__, dentry);
223 
224         affs_lock_dir(dir);
225         bh = affs_find_entry(dir, dentry);
226         affs_unlock_dir(dir);
227         if (IS_ERR(bh))
228                 return ERR_CAST(bh);
229         if (bh) {
230                 u32 ino = bh->b_blocknr;
231 
232                 /* store the real header ino in d_fsdata for faster lookups */
233                 dentry->d_fsdata = (void *)(long)ino;
234                 switch (be32_to_cpu(AFFS_TAIL(sb, bh)->stype)) {
235                 //link to dirs disabled
236                 //case ST_LINKDIR:
237                 case ST_LINKFILE:
238                         ino = be32_to_cpu(AFFS_TAIL(sb, bh)->original);
239                 }
240                 affs_brelse(bh);
241                 inode = affs_iget(sb, ino);
242                 if (IS_ERR(inode))
243                         return ERR_CAST(inode);
244         }
245         d_add(dentry, inode);
246         return NULL;
247 }
248 
249 int
250 affs_unlink(struct inode *dir, struct dentry *dentry)
251 {
252         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
253                  dentry->d_inode->i_ino, dentry);
254 
255         return affs_remove_header(dentry);
256 }
257 
258 int
259 affs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
260 {
261         struct super_block *sb = dir->i_sb;
262         struct inode    *inode;
263         int              error;
264 
265         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
266                  __func__, dir->i_ino, dentry, mode);
267 
268         inode = affs_new_inode(dir);
269         if (!inode)
270                 return -ENOSPC;
271 
272         inode->i_mode = mode;
273         mode_to_prot(inode);
274         mark_inode_dirty(inode);
275 
276         inode->i_op = &affs_file_inode_operations;
277         inode->i_fop = &affs_file_operations;
278         inode->i_mapping->a_ops = (AFFS_SB(sb)->s_flags & SF_OFS) ? &affs_aops_ofs : &affs_aops;
279         error = affs_add_entry(dir, inode, dentry, ST_FILE);
280         if (error) {
281                 clear_nlink(inode);
282                 iput(inode);
283                 return error;
284         }
285         return 0;
286 }
287 
288 int
289 affs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
290 {
291         struct inode            *inode;
292         int                      error;
293 
294         pr_debug("%s(%lu,\"%pd\",0%ho)\n",
295                  __func__, dir->i_ino, dentry, mode);
296 
297         inode = affs_new_inode(dir);
298         if (!inode)
299                 return -ENOSPC;
300 
301         inode->i_mode = S_IFDIR | mode;
302         mode_to_prot(inode);
303 
304         inode->i_op = &affs_dir_inode_operations;
305         inode->i_fop = &affs_dir_operations;
306 
307         error = affs_add_entry(dir, inode, dentry, ST_USERDIR);
308         if (error) {
309                 clear_nlink(inode);
310                 mark_inode_dirty(inode);
311                 iput(inode);
312                 return error;
313         }
314         return 0;
315 }
316 
317 int
318 affs_rmdir(struct inode *dir, struct dentry *dentry)
319 {
320         pr_debug("%s(dir=%lu, %lu \"%pd\")\n", __func__, dir->i_ino,
321                  dentry->d_inode->i_ino, dentry);
322 
323         return affs_remove_header(dentry);
324 }
325 
326 int
327 affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
328 {
329         struct super_block      *sb = dir->i_sb;
330         struct buffer_head      *bh;
331         struct inode            *inode;
332         char                    *p;
333         int                      i, maxlen, error;
334         char                     c, lc;
335 
336         pr_debug("%s(%lu,\"%pd\" -> \"%s\")\n",
337                  __func__, dir->i_ino, dentry, symname);
338 
339         maxlen = AFFS_SB(sb)->s_hashsize * sizeof(u32) - 1;
340         inode  = affs_new_inode(dir);
341         if (!inode)
342                 return -ENOSPC;
343 
344         inode->i_op = &affs_symlink_inode_operations;
345         inode->i_data.a_ops = &affs_symlink_aops;
346         inode->i_mode = S_IFLNK | 0777;
347         mode_to_prot(inode);
348 
349         error = -EIO;
350         bh = affs_bread(sb, inode->i_ino);
351         if (!bh)
352                 goto err;
353         i  = 0;
354         p  = (char *)AFFS_HEAD(bh)->table;
355         lc = '/';
356         if (*symname == '/') {
357                 struct affs_sb_info *sbi = AFFS_SB(sb);
358                 while (*symname == '/')
359                         symname++;
360                 spin_lock(&sbi->symlink_lock);
361                 while (sbi->s_volume[i])        /* Cannot overflow */
362                         *p++ = sbi->s_volume[i++];
363                 spin_unlock(&sbi->symlink_lock);
364         }
365         while (i < maxlen && (c = *symname++)) {
366                 if (c == '.' && lc == '/' && *symname == '.' && symname[1] == '/') {
367                         *p++ = '/';
368                         i++;
369                         symname += 2;
370                         lc = '/';
371                 } else if (c == '.' && lc == '/' && *symname == '/') {
372                         symname++;
373                         lc = '/';
374                 } else {
375                         *p++ = c;
376                         lc   = c;
377                         i++;
378                 }
379                 if (lc == '/')
380                         while (*symname == '/')
381                                 symname++;
382         }
383         *p = 0;
384         mark_buffer_dirty_inode(bh, inode);
385         affs_brelse(bh);
386         mark_inode_dirty(inode);
387 
388         error = affs_add_entry(dir, inode, dentry, ST_SOFTLINK);
389         if (error)
390                 goto err;
391 
392         return 0;
393 
394 err:
395         clear_nlink(inode);
396         mark_inode_dirty(inode);
397         iput(inode);
398         return error;
399 }
400 
401 int
402 affs_link(struct dentry *old_dentry, struct inode *dir, struct dentry *dentry)
403 {
404         struct inode *inode = old_dentry->d_inode;
405 
406         pr_debug("%s(%lu, %lu, \"%pd\")\n", __func__, inode->i_ino, dir->i_ino,
407                  dentry);
408 
409         return affs_add_entry(dir, inode, dentry, ST_LINKFILE);
410 }
411 
412 int
413 affs_rename(struct inode *old_dir, struct dentry *old_dentry,
414             struct inode *new_dir, struct dentry *new_dentry)
415 {
416         struct super_block *sb = old_dir->i_sb;
417         struct buffer_head *bh = NULL;
418         int retval;
419 
420         pr_debug("%s(old=%lu,\"%pd\" to new=%lu,\"%pd\")\n", __func__,
421                  old_dir->i_ino, old_dentry, new_dir->i_ino, new_dentry);
422 
423         retval = affs_check_name(new_dentry->d_name.name,
424                                  new_dentry->d_name.len,
425                                  affs_nofilenametruncate(old_dentry));
426 
427         if (retval)
428                 return retval;
429 
430         /* Unlink destination if it already exists */
431         if (new_dentry->d_inode) {
432                 retval = affs_remove_header(new_dentry);
433                 if (retval)
434                         return retval;
435         }
436 
437         bh = affs_bread(sb, old_dentry->d_inode->i_ino);
438         if (!bh)
439                 return -EIO;
440 
441         /* Remove header from its parent directory. */
442         affs_lock_dir(old_dir);
443         retval = affs_remove_hash(old_dir, bh);
444         affs_unlock_dir(old_dir);
445         if (retval)
446                 goto done;
447 
448         /* And insert it into the new directory with the new name. */
449         affs_copy_name(AFFS_TAIL(sb, bh)->name, new_dentry);
450         affs_fix_checksum(sb, bh);
451         affs_lock_dir(new_dir);
452         retval = affs_insert_hash(new_dir, bh);
453         affs_unlock_dir(new_dir);
454         /* TODO: move it back to old_dir, if error? */
455 
456 done:
457         mark_buffer_dirty_inode(bh, retval ? old_dir : new_dir);
458         affs_brelse(bh);
459         return retval;
460 }
461 

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