Commit | Line | Data |
---|---|---|
1da177e4 LT |
1 | /* |
2 | * file.c - part of debugfs, a tiny little debug file system | |
3 | * | |
4 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> | |
5 | * Copyright (C) 2004 IBM Inc. | |
6 | * | |
7 | * This program is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU General Public License version | |
9 | * 2 as published by the Free Software Foundation. | |
10 | * | |
11 | * debugfs is for people to use instead of /proc or /sys. | |
12 | * See Documentation/DocBook/kernel-api for more details. | |
13 | * | |
14 | */ | |
15 | ||
16 | /* uncomment to get debug messages from the debug filesystem, ah the irony. */ | |
17 | /* #define DEBUG */ | |
18 | ||
1da177e4 LT |
19 | #include <linux/module.h> |
20 | #include <linux/fs.h> | |
21 | #include <linux/mount.h> | |
22 | #include <linux/pagemap.h> | |
23 | #include <linux/init.h> | |
4d8ebddc | 24 | #include <linux/kobject.h> |
1da177e4 LT |
25 | #include <linux/namei.h> |
26 | #include <linux/debugfs.h> | |
4f36557f | 27 | #include <linux/fsnotify.h> |
66f54963 | 28 | #include <linux/string.h> |
92562927 | 29 | #include <linux/magic.h> |
1da177e4 | 30 | |
1da177e4 LT |
31 | static struct vfsmount *debugfs_mount; |
32 | static int debugfs_mount_count; | |
33 | ||
34 | static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev) | |
35 | { | |
36 | struct inode *inode = new_inode(sb); | |
37 | ||
38 | if (inode) { | |
39 | inode->i_mode = mode; | |
1da177e4 LT |
40 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
41 | switch (mode & S_IFMT) { | |
42 | default: | |
43 | init_special_inode(inode, mode, dev); | |
44 | break; | |
45 | case S_IFREG: | |
46 | inode->i_fop = &debugfs_file_operations; | |
47 | break; | |
66f54963 PO |
48 | case S_IFLNK: |
49 | inode->i_op = &debugfs_link_operations; | |
50 | break; | |
1da177e4 LT |
51 | case S_IFDIR: |
52 | inode->i_op = &simple_dir_inode_operations; | |
53 | inode->i_fop = &simple_dir_operations; | |
54 | ||
bafb232e MD |
55 | /* directory inodes start off with i_nlink == 2 |
56 | * (for "." entry) */ | |
d8c76e6f | 57 | inc_nlink(inode); |
1da177e4 LT |
58 | break; |
59 | } | |
60 | } | |
61 | return inode; | |
62 | } | |
63 | ||
64 | /* SMP-safe */ | |
65 | static int debugfs_mknod(struct inode *dir, struct dentry *dentry, | |
66 | int mode, dev_t dev) | |
67 | { | |
71601e2b | 68 | struct inode *inode; |
1da177e4 LT |
69 | int error = -EPERM; |
70 | ||
71 | if (dentry->d_inode) | |
72 | return -EEXIST; | |
73 | ||
71601e2b | 74 | inode = debugfs_get_inode(dir->i_sb, mode, dev); |
1da177e4 LT |
75 | if (inode) { |
76 | d_instantiate(dentry, inode); | |
77 | dget(dentry); | |
78 | error = 0; | |
79 | } | |
80 | return error; | |
81 | } | |
82 | ||
83 | static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode) | |
84 | { | |
85 | int res; | |
86 | ||
87 | mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; | |
88 | res = debugfs_mknod(dir, dentry, mode, 0); | |
4f36557f | 89 | if (!res) { |
d8c76e6f | 90 | inc_nlink(dir); |
4f36557f MD |
91 | fsnotify_mkdir(dir, dentry); |
92 | } | |
1da177e4 LT |
93 | return res; |
94 | } | |
95 | ||
66f54963 PO |
96 | static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode) |
97 | { | |
98 | mode = (mode & S_IALLUGO) | S_IFLNK; | |
99 | return debugfs_mknod(dir, dentry, mode, 0); | |
100 | } | |
101 | ||
1da177e4 LT |
102 | static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode) |
103 | { | |
4f36557f MD |
104 | int res; |
105 | ||
1da177e4 | 106 | mode = (mode & S_IALLUGO) | S_IFREG; |
4f36557f MD |
107 | res = debugfs_mknod(dir, dentry, mode, 0); |
108 | if (!res) | |
109 | fsnotify_create(dir, dentry); | |
110 | return res; | |
1da177e4 LT |
111 | } |
112 | ||
113 | static inline int debugfs_positive(struct dentry *dentry) | |
114 | { | |
115 | return dentry->d_inode && !d_unhashed(dentry); | |
116 | } | |
117 | ||
118 | static int debug_fill_super(struct super_block *sb, void *data, int silent) | |
119 | { | |
120 | static struct tree_descr debug_files[] = {{""}}; | |
121 | ||
122 | return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
123 | } | |
124 | ||
454e2398 DH |
125 | static int debug_get_sb(struct file_system_type *fs_type, |
126 | int flags, const char *dev_name, | |
127 | void *data, struct vfsmount *mnt) | |
1da177e4 | 128 | { |
454e2398 | 129 | return get_sb_single(fs_type, flags, data, debug_fill_super, mnt); |
1da177e4 LT |
130 | } |
131 | ||
132 | static struct file_system_type debug_fs_type = { | |
133 | .owner = THIS_MODULE, | |
134 | .name = "debugfs", | |
135 | .get_sb = debug_get_sb, | |
136 | .kill_sb = kill_litter_super, | |
137 | }; | |
138 | ||
139 | static int debugfs_create_by_name(const char *name, mode_t mode, | |
140 | struct dentry *parent, | |
141 | struct dentry **dentry) | |
142 | { | |
143 | int error = 0; | |
144 | ||
145 | /* If the parent is not specified, we create it in the root. | |
146 | * We need the root dentry to do this, which is in the super | |
147 | * block. A pointer to that is in the struct vfsmount that we | |
148 | * have around. | |
149 | */ | |
bafb232e | 150 | if (!parent) { |
1da177e4 LT |
151 | if (debugfs_mount && debugfs_mount->mnt_sb) { |
152 | parent = debugfs_mount->mnt_sb->s_root; | |
153 | } | |
154 | } | |
155 | if (!parent) { | |
156 | pr_debug("debugfs: Ah! can not find a parent!\n"); | |
157 | return -EFAULT; | |
158 | } | |
159 | ||
160 | *dentry = NULL; | |
1b1dcc1b | 161 | mutex_lock(&parent->d_inode->i_mutex); |
5f45f1a7 | 162 | *dentry = lookup_one_len(name, parent, strlen(name)); |
7bb0386f | 163 | if (!IS_ERR(*dentry)) { |
66f54963 PO |
164 | switch (mode & S_IFMT) { |
165 | case S_IFDIR: | |
1da177e4 | 166 | error = debugfs_mkdir(parent->d_inode, *dentry, mode); |
66f54963 PO |
167 | break; |
168 | case S_IFLNK: | |
169 | error = debugfs_link(parent->d_inode, *dentry, mode); | |
170 | break; | |
171 | default: | |
1da177e4 | 172 | error = debugfs_create(parent->d_inode, *dentry, mode); |
66f54963 PO |
173 | break; |
174 | } | |
65c33336 | 175 | dput(*dentry); |
1da177e4 | 176 | } else |
7bb0386f | 177 | error = PTR_ERR(*dentry); |
1b1dcc1b | 178 | mutex_unlock(&parent->d_inode->i_mutex); |
1da177e4 LT |
179 | |
180 | return error; | |
181 | } | |
182 | ||
183 | /** | |
184 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 LT |
185 | * @name: a pointer to a string containing the name of the file to create. |
186 | * @mode: the permission that the file should have | |
187 | * @parent: a pointer to the parent dentry for this file. This should be a | |
188 | * directory dentry if set. If this paramater is NULL, then the | |
189 | * file will be created in the root of the debugfs filesystem. | |
190 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 191 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
192 | * the open() call. |
193 | * @fops: a pointer to a struct file_operations that should be used for | |
194 | * this file. | |
195 | * | |
196 | * This is the basic "create a file" function for debugfs. It allows for a | |
197 | * wide range of flexibility in createing a file, or a directory (if you | |
198 | * want to create a directory, the debugfs_create_dir() function is | |
199 | * recommended to be used instead.) | |
200 | * | |
201 | * This function will return a pointer to a dentry if it succeeds. This | |
202 | * pointer must be passed to the debugfs_remove() function when the file is | |
203 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 204 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 205 | * |
6468b3af | 206 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 207 | * returned. |
1da177e4 LT |
208 | */ |
209 | struct dentry *debugfs_create_file(const char *name, mode_t mode, | |
210 | struct dentry *parent, void *data, | |
99ac48f5 | 211 | const struct file_operations *fops) |
1da177e4 LT |
212 | { |
213 | struct dentry *dentry = NULL; | |
214 | int error; | |
215 | ||
216 | pr_debug("debugfs: creating file '%s'\n",name); | |
217 | ||
63223a06 MD |
218 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
219 | &debugfs_mount_count); | |
1da177e4 LT |
220 | if (error) |
221 | goto exit; | |
222 | ||
223 | error = debugfs_create_by_name(name, mode, parent, &dentry); | |
224 | if (error) { | |
225 | dentry = NULL; | |
63223a06 | 226 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
1da177e4 LT |
227 | goto exit; |
228 | } | |
229 | ||
230 | if (dentry->d_inode) { | |
231 | if (data) | |
8e18e294 | 232 | dentry->d_inode->i_private = data; |
1da177e4 LT |
233 | if (fops) |
234 | dentry->d_inode->i_fop = fops; | |
235 | } | |
236 | exit: | |
237 | return dentry; | |
238 | } | |
239 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
240 | ||
241 | /** | |
242 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
243 | * @name: a pointer to a string containing the name of the directory to |
244 | * create. | |
245 | * @parent: a pointer to the parent dentry for this file. This should be a | |
246 | * directory dentry if set. If this paramater is NULL, then the | |
247 | * directory will be created in the root of the debugfs filesystem. | |
248 | * | |
249 | * This function creates a directory in debugfs with the given name. | |
250 | * | |
251 | * This function will return a pointer to a dentry if it succeeds. This | |
252 | * pointer must be passed to the debugfs_remove() function when the file is | |
253 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 254 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 255 | * |
6468b3af | 256 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 257 | * returned. |
1da177e4 LT |
258 | */ |
259 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
260 | { | |
261 | return debugfs_create_file(name, | |
262 | S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, | |
263 | parent, NULL, NULL); | |
264 | } | |
265 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
266 | ||
66f54963 PO |
267 | /** |
268 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
269 | * @name: a pointer to a string containing the name of the symbolic link to | |
270 | * create. | |
271 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
272 | * should be a directory dentry if set. If this paramater is NULL, | |
273 | * then the symbolic link will be created in the root of the debugfs | |
274 | * filesystem. | |
275 | * @target: a pointer to a string containing the path to the target of the | |
276 | * symbolic link. | |
277 | * | |
278 | * This function creates a symbolic link with the given name in debugfs that | |
279 | * links to the given target path. | |
280 | * | |
281 | * This function will return a pointer to a dentry if it succeeds. This | |
282 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
283 | * link is to be removed (no automatic cleanup happens if your module is | |
284 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
285 | * returned. | |
286 | * | |
287 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 288 | * returned. |
66f54963 PO |
289 | */ |
290 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
291 | const char *target) | |
292 | { | |
293 | struct dentry *result; | |
294 | char *link; | |
295 | ||
296 | link = kstrdup(target, GFP_KERNEL); | |
297 | if (!link) | |
298 | return NULL; | |
299 | ||
300 | result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link, | |
301 | NULL); | |
302 | if (!result) | |
303 | kfree(link); | |
304 | return result; | |
305 | } | |
306 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
307 | ||
9505e637 HS |
308 | static void __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
309 | { | |
310 | int ret = 0; | |
311 | ||
312 | if (debugfs_positive(dentry)) { | |
313 | if (dentry->d_inode) { | |
314 | dget(dentry); | |
315 | switch (dentry->d_inode->i_mode & S_IFMT) { | |
316 | case S_IFDIR: | |
317 | ret = simple_rmdir(parent->d_inode, dentry); | |
318 | break; | |
319 | case S_IFLNK: | |
320 | kfree(dentry->d_inode->i_private); | |
321 | /* fall through */ | |
322 | default: | |
323 | simple_unlink(parent->d_inode, dentry); | |
324 | break; | |
325 | } | |
326 | if (!ret) | |
327 | d_delete(dentry); | |
328 | dput(dentry); | |
329 | } | |
330 | } | |
331 | } | |
332 | ||
1da177e4 LT |
333 | /** |
334 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 LT |
335 | * @dentry: a pointer to a the dentry of the file or directory to be |
336 | * removed. | |
337 | * | |
338 | * This function removes a file or directory in debugfs that was previously | |
339 | * created with a call to another debugfs function (like | |
5a65980e | 340 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
341 | * |
342 | * This function is required to be called in order for the file to be | |
343 | * removed, no automatic cleanup of files will happen when a module is | |
344 | * removed, you are responsible here. | |
345 | */ | |
346 | void debugfs_remove(struct dentry *dentry) | |
347 | { | |
348 | struct dentry *parent; | |
349 | ||
350 | if (!dentry) | |
351 | return; | |
352 | ||
353 | parent = dentry->d_parent; | |
354 | if (!parent || !parent->d_inode) | |
355 | return; | |
356 | ||
1b1dcc1b | 357 | mutex_lock(&parent->d_inode->i_mutex); |
9505e637 HS |
358 | __debugfs_remove(dentry, parent); |
359 | mutex_unlock(&parent->d_inode->i_mutex); | |
360 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
361 | } | |
362 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
363 | ||
364 | /** | |
365 | * debugfs_remove_recursive - recursively removes a directory | |
366 | * @dentry: a pointer to a the dentry of the directory to be removed. | |
367 | * | |
368 | * This function recursively removes a directory tree in debugfs that | |
369 | * was previously created with a call to another debugfs function | |
370 | * (like debugfs_create_file() or variants thereof.) | |
371 | * | |
372 | * This function is required to be called in order for the file to be | |
373 | * removed, no automatic cleanup of files will happen when a module is | |
374 | * removed, you are responsible here. | |
375 | */ | |
376 | void debugfs_remove_recursive(struct dentry *dentry) | |
377 | { | |
378 | struct dentry *child; | |
379 | struct dentry *parent; | |
380 | ||
381 | if (!dentry) | |
382 | return; | |
383 | ||
384 | parent = dentry->d_parent; | |
385 | if (!parent || !parent->d_inode) | |
386 | return; | |
387 | ||
388 | parent = dentry; | |
389 | mutex_lock(&parent->d_inode->i_mutex); | |
390 | ||
391 | while (1) { | |
392 | /* | |
393 | * When all dentries under "parent" has been removed, | |
394 | * walk up the tree until we reach our starting point. | |
395 | */ | |
396 | if (list_empty(&parent->d_subdirs)) { | |
397 | mutex_unlock(&parent->d_inode->i_mutex); | |
398 | if (parent == dentry) | |
66f54963 | 399 | break; |
9505e637 HS |
400 | parent = parent->d_parent; |
401 | mutex_lock(&parent->d_inode->i_mutex); | |
402 | } | |
403 | child = list_entry(parent->d_subdirs.next, struct dentry, | |
404 | d_u.d_child); | |
405 | ||
406 | /* | |
407 | * If "child" isn't empty, walk down the tree and | |
408 | * remove all its descendants first. | |
409 | */ | |
410 | if (!list_empty(&child->d_subdirs)) { | |
411 | mutex_unlock(&parent->d_inode->i_mutex); | |
412 | parent = child; | |
413 | mutex_lock(&parent->d_inode->i_mutex); | |
414 | continue; | |
1da177e4 | 415 | } |
9505e637 HS |
416 | __debugfs_remove(child, parent); |
417 | if (parent->d_subdirs.next == &child->d_u.d_child) { | |
418 | /* | |
419 | * Avoid infinite loop if we fail to remove | |
420 | * one dentry. | |
421 | */ | |
422 | mutex_unlock(&parent->d_inode->i_mutex); | |
423 | break; | |
424 | } | |
425 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1da177e4 | 426 | } |
9505e637 HS |
427 | |
428 | parent = dentry->d_parent; | |
429 | mutex_lock(&parent->d_inode->i_mutex); | |
430 | __debugfs_remove(dentry, parent); | |
1b1dcc1b | 431 | mutex_unlock(&parent->d_inode->i_mutex); |
1da177e4 LT |
432 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
433 | } | |
9505e637 | 434 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 435 | |
cfc94cdf JK |
436 | /** |
437 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
438 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
439 | * should be a directory dentry. | |
440 | * @old_dentry: dentry of an object to be renamed. | |
441 | * @new_dir: a pointer to the parent dentry where the object should be | |
442 | * moved. This should be a directory dentry. | |
443 | * @new_name: a pointer to a string containing the target name. | |
444 | * | |
445 | * This function renames a file/directory in debugfs. The target must not | |
446 | * exist for rename to succeed. | |
447 | * | |
448 | * This function will return a pointer to old_dentry (which is updated to | |
449 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
450 | * returned. | |
451 | * | |
452 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
453 | * returned. | |
454 | */ | |
455 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
456 | struct dentry *new_dir, const char *new_name) | |
457 | { | |
458 | int error; | |
459 | struct dentry *dentry = NULL, *trap; | |
460 | const char *old_name; | |
461 | ||
462 | trap = lock_rename(new_dir, old_dir); | |
463 | /* Source or destination directories don't exist? */ | |
464 | if (!old_dir->d_inode || !new_dir->d_inode) | |
465 | goto exit; | |
466 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
467 | if (!old_dentry->d_inode || old_dentry == trap || | |
468 | d_mountpoint(old_dentry)) | |
469 | goto exit; | |
470 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
471 | /* Lookup failed, cyclic rename or target exists? */ | |
472 | if (IS_ERR(dentry) || dentry == trap || dentry->d_inode) | |
473 | goto exit; | |
474 | ||
475 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); | |
476 | ||
477 | error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, | |
478 | dentry); | |
479 | if (error) { | |
480 | fsnotify_oldname_free(old_name); | |
481 | goto exit; | |
482 | } | |
483 | d_move(old_dentry, dentry); | |
484 | fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name, | |
485 | old_dentry->d_name.name, S_ISDIR(old_dentry->d_inode->i_mode), | |
5a190ae6 | 486 | NULL, old_dentry); |
cfc94cdf JK |
487 | fsnotify_oldname_free(old_name); |
488 | unlock_rename(new_dir, old_dir); | |
489 | dput(dentry); | |
490 | return old_dentry; | |
491 | exit: | |
492 | if (dentry && !IS_ERR(dentry)) | |
493 | dput(dentry); | |
494 | unlock_rename(new_dir, old_dir); | |
495 | return NULL; | |
496 | } | |
497 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
498 | ||
191e186b | 499 | static struct kobject *debug_kobj; |
1da177e4 LT |
500 | |
501 | static int __init debugfs_init(void) | |
502 | { | |
503 | int retval; | |
504 | ||
0ff21e46 | 505 | debug_kobj = kobject_create_and_add("debug", kernel_kobj); |
191e186b GKH |
506 | if (!debug_kobj) |
507 | return -EINVAL; | |
1da177e4 LT |
508 | |
509 | retval = register_filesystem(&debug_fs_type); | |
510 | if (retval) | |
197b12d6 | 511 | kobject_put(debug_kobj); |
1da177e4 LT |
512 | return retval; |
513 | } | |
514 | ||
515 | static void __exit debugfs_exit(void) | |
516 | { | |
517 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
518 | unregister_filesystem(&debug_fs_type); | |
197b12d6 | 519 | kobject_put(debug_kobj); |
1da177e4 LT |
520 | } |
521 | ||
522 | core_initcall(debugfs_init); | |
523 | module_exit(debugfs_exit); | |
524 | MODULE_LICENSE("GPL"); | |
525 |