Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
bd33d12f | 2 | * inode.c - part of debugfs, a tiny little debug file system |
1da177e4 LT |
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 | ||
1da177e4 LT |
16 | #include <linux/module.h> |
17 | #include <linux/fs.h> | |
18 | #include <linux/mount.h> | |
19 | #include <linux/pagemap.h> | |
20 | #include <linux/init.h> | |
4d8ebddc | 21 | #include <linux/kobject.h> |
1da177e4 LT |
22 | #include <linux/namei.h> |
23 | #include <linux/debugfs.h> | |
4f36557f | 24 | #include <linux/fsnotify.h> |
66f54963 | 25 | #include <linux/string.h> |
d6e48686 LN |
26 | #include <linux/seq_file.h> |
27 | #include <linux/parser.h> | |
92562927 | 28 | #include <linux/magic.h> |
5a0e3ad6 | 29 | #include <linux/slab.h> |
1da177e4 | 30 | |
82aceae4 | 31 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 32 | |
1da177e4 LT |
33 | static struct vfsmount *debugfs_mount; |
34 | static int debugfs_mount_count; | |
c0f92ba9 | 35 | static bool debugfs_registered; |
1da177e4 | 36 | |
edac65ea | 37 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
38 | { |
39 | struct inode *inode = new_inode(sb); | |
1da177e4 | 40 | if (inode) { |
85fe4025 | 41 | inode->i_ino = get_next_ino(); |
1da177e4 | 42 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
1da177e4 | 43 | } |
88e412ea | 44 | return inode; |
1da177e4 LT |
45 | } |
46 | ||
1da177e4 LT |
47 | static inline int debugfs_positive(struct dentry *dentry) |
48 | { | |
49 | return dentry->d_inode && !d_unhashed(dentry); | |
50 | } | |
51 | ||
d6e48686 | 52 | struct debugfs_mount_opts { |
7dc05881 EB |
53 | kuid_t uid; |
54 | kgid_t gid; | |
d6e48686 LN |
55 | umode_t mode; |
56 | }; | |
57 | ||
58 | enum { | |
59 | Opt_uid, | |
60 | Opt_gid, | |
61 | Opt_mode, | |
62 | Opt_err | |
63 | }; | |
64 | ||
65 | static const match_table_t tokens = { | |
66 | {Opt_uid, "uid=%u"}, | |
67 | {Opt_gid, "gid=%u"}, | |
68 | {Opt_mode, "mode=%o"}, | |
69 | {Opt_err, NULL} | |
70 | }; | |
71 | ||
72 | struct debugfs_fs_info { | |
73 | struct debugfs_mount_opts mount_opts; | |
74 | }; | |
75 | ||
76 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
77 | { | |
78 | substring_t args[MAX_OPT_ARGS]; | |
79 | int option; | |
80 | int token; | |
7dc05881 EB |
81 | kuid_t uid; |
82 | kgid_t gid; | |
d6e48686 LN |
83 | char *p; |
84 | ||
85 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
86 | ||
87 | while ((p = strsep(&data, ",")) != NULL) { | |
88 | if (!*p) | |
89 | continue; | |
90 | ||
91 | token = match_token(p, tokens, args); | |
92 | switch (token) { | |
93 | case Opt_uid: | |
94 | if (match_int(&args[0], &option)) | |
95 | return -EINVAL; | |
7dc05881 EB |
96 | uid = make_kuid(current_user_ns(), option); |
97 | if (!uid_valid(uid)) | |
98 | return -EINVAL; | |
99 | opts->uid = uid; | |
d6e48686 LN |
100 | break; |
101 | case Opt_gid: | |
f1688e04 | 102 | if (match_int(&args[0], &option)) |
d6e48686 | 103 | return -EINVAL; |
7dc05881 EB |
104 | gid = make_kgid(current_user_ns(), option); |
105 | if (!gid_valid(gid)) | |
106 | return -EINVAL; | |
107 | opts->gid = gid; | |
d6e48686 LN |
108 | break; |
109 | case Opt_mode: | |
110 | if (match_octal(&args[0], &option)) | |
111 | return -EINVAL; | |
112 | opts->mode = option & S_IALLUGO; | |
113 | break; | |
114 | /* | |
115 | * We might like to report bad mount options here; | |
116 | * but traditionally debugfs has ignored all mount options | |
117 | */ | |
118 | } | |
119 | } | |
120 | ||
121 | return 0; | |
122 | } | |
123 | ||
124 | static int debugfs_apply_options(struct super_block *sb) | |
125 | { | |
126 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
127 | struct inode *inode = sb->s_root->d_inode; | |
128 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
129 | ||
130 | inode->i_mode &= ~S_IALLUGO; | |
131 | inode->i_mode |= opts->mode; | |
132 | ||
133 | inode->i_uid = opts->uid; | |
134 | inode->i_gid = opts->gid; | |
135 | ||
136 | return 0; | |
137 | } | |
138 | ||
139 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
140 | { | |
141 | int err; | |
142 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
143 | ||
02b9984d | 144 | sync_filesystem(sb); |
d6e48686 LN |
145 | err = debugfs_parse_options(data, &fsi->mount_opts); |
146 | if (err) | |
147 | goto fail; | |
148 | ||
149 | debugfs_apply_options(sb); | |
150 | ||
151 | fail: | |
152 | return err; | |
153 | } | |
154 | ||
155 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
156 | { | |
157 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
158 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
159 | ||
7dc05881 EB |
160 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
161 | seq_printf(m, ",uid=%u", | |
162 | from_kuid_munged(&init_user_ns, opts->uid)); | |
163 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
164 | seq_printf(m, ",gid=%u", | |
165 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
166 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
167 | seq_printf(m, ",mode=%o", opts->mode); | |
168 | ||
169 | return 0; | |
170 | } | |
171 | ||
0db59e59 AV |
172 | static void debugfs_evict_inode(struct inode *inode) |
173 | { | |
174 | truncate_inode_pages_final(&inode->i_data); | |
175 | clear_inode(inode); | |
176 | if (S_ISLNK(inode->i_mode)) | |
177 | kfree(inode->i_private); | |
178 | } | |
179 | ||
d6e48686 LN |
180 | static const struct super_operations debugfs_super_operations = { |
181 | .statfs = simple_statfs, | |
182 | .remount_fs = debugfs_remount, | |
183 | .show_options = debugfs_show_options, | |
0db59e59 | 184 | .evict_inode = debugfs_evict_inode, |
d6e48686 LN |
185 | }; |
186 | ||
77b3da6e AV |
187 | static struct vfsmount *debugfs_automount(struct path *path) |
188 | { | |
189 | struct vfsmount *(*f)(void *); | |
190 | f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata; | |
191 | return f(path->dentry->d_inode->i_private); | |
192 | } | |
193 | ||
194 | static const struct dentry_operations debugfs_dops = { | |
195 | .d_delete = always_delete_dentry, | |
196 | .d_automount = debugfs_automount, | |
197 | }; | |
198 | ||
1da177e4 LT |
199 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
200 | { | |
201 | static struct tree_descr debug_files[] = {{""}}; | |
d6e48686 LN |
202 | struct debugfs_fs_info *fsi; |
203 | int err; | |
204 | ||
205 | save_mount_options(sb, data); | |
206 | ||
207 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); | |
208 | sb->s_fs_info = fsi; | |
209 | if (!fsi) { | |
210 | err = -ENOMEM; | |
211 | goto fail; | |
212 | } | |
213 | ||
214 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
215 | if (err) | |
216 | goto fail; | |
217 | ||
218 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
219 | if (err) | |
220 | goto fail; | |
221 | ||
222 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 223 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
224 | |
225 | debugfs_apply_options(sb); | |
226 | ||
227 | return 0; | |
1da177e4 | 228 | |
d6e48686 LN |
229 | fail: |
230 | kfree(fsi); | |
231 | sb->s_fs_info = NULL; | |
232 | return err; | |
1da177e4 LT |
233 | } |
234 | ||
fc14f2fe | 235 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 236 | int flags, const char *dev_name, |
fc14f2fe | 237 | void *data) |
1da177e4 | 238 | { |
fc14f2fe | 239 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
240 | } |
241 | ||
242 | static struct file_system_type debug_fs_type = { | |
243 | .owner = THIS_MODULE, | |
244 | .name = "debugfs", | |
fc14f2fe | 245 | .mount = debug_mount, |
1da177e4 LT |
246 | .kill_sb = kill_litter_super, |
247 | }; | |
7f78e035 | 248 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 249 | |
190afd81 | 250 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 251 | { |
190afd81 | 252 | struct dentry *dentry; |
cfa57c11 AV |
253 | int error; |
254 | ||
255 | pr_debug("debugfs: creating file '%s'\n",name); | |
256 | ||
257 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, | |
258 | &debugfs_mount_count); | |
259 | if (error) | |
190afd81 | 260 | return ERR_PTR(error); |
1da177e4 LT |
261 | |
262 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 263 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
264 | * block. A pointer to that is in the struct vfsmount that we |
265 | * have around. | |
266 | */ | |
ef52c75e | 267 | if (!parent) |
4c1d5a64 | 268 | parent = debugfs_mount->mnt_root; |
1da177e4 | 269 | |
1b1dcc1b | 270 | mutex_lock(&parent->d_inode->i_mutex); |
cfa57c11 | 271 | dentry = lookup_one_len(name, parent, strlen(name)); |
190afd81 | 272 | if (!IS_ERR(dentry) && dentry->d_inode) { |
cfa57c11 | 273 | dput(dentry); |
190afd81 AV |
274 | dentry = ERR_PTR(-EEXIST); |
275 | } | |
276 | if (IS_ERR(dentry)) | |
277 | mutex_unlock(&parent->d_inode->i_mutex); | |
278 | return dentry; | |
279 | } | |
280 | ||
5233e311 | 281 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 AV |
282 | { |
283 | mutex_unlock(&dentry->d_parent->d_inode->i_mutex); | |
284 | dput(dentry); | |
5233e311 AV |
285 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
286 | return NULL; | |
287 | } | |
1da177e4 | 288 | |
5233e311 AV |
289 | static struct dentry *end_creating(struct dentry *dentry) |
290 | { | |
291 | mutex_unlock(&dentry->d_parent->d_inode->i_mutex); | |
c3b1a350 AV |
292 | return dentry; |
293 | } | |
294 | ||
1da177e4 LT |
295 | /** |
296 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 297 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 298 | * @mode: the permission that the file should have. |
1da177e4 | 299 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 300 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
301 | * file will be created in the root of the debugfs filesystem. |
302 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 303 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
304 | * the open() call. |
305 | * @fops: a pointer to a struct file_operations that should be used for | |
306 | * this file. | |
307 | * | |
308 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
309 | * wide range of flexibility in creating a file, or a directory (if you want |
310 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
311 | * recommended to be used instead.) |
312 | * | |
313 | * This function will return a pointer to a dentry if it succeeds. This | |
314 | * pointer must be passed to the debugfs_remove() function when the file is | |
315 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 316 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 317 | * |
6468b3af | 318 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 319 | * returned. |
1da177e4 | 320 | */ |
f4ae40a6 | 321 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 322 | struct dentry *parent, void *data, |
99ac48f5 | 323 | const struct file_operations *fops) |
1da177e4 | 324 | { |
ad5abd5b | 325 | struct dentry *dentry; |
680b3024 | 326 | struct inode *inode; |
ad5abd5b AV |
327 | |
328 | if (!(mode & S_IFMT)) | |
329 | mode |= S_IFREG; | |
330 | BUG_ON(!S_ISREG(mode)); | |
331 | dentry = start_creating(name, parent); | |
332 | ||
333 | if (IS_ERR(dentry)) | |
334 | return NULL; | |
c3b1a350 | 335 | |
edac65ea | 336 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 337 | if (unlikely(!inode)) |
5233e311 | 338 | return failed_creating(dentry); |
680b3024 | 339 | |
edac65ea AV |
340 | inode->i_mode = mode; |
341 | inode->i_fop = fops ? fops : &debugfs_file_operations; | |
342 | inode->i_private = data; | |
680b3024 | 343 | d_instantiate(dentry, inode); |
680b3024 | 344 | fsnotify_create(dentry->d_parent->d_inode, dentry); |
5233e311 | 345 | return end_creating(dentry); |
1da177e4 LT |
346 | } |
347 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
348 | ||
e59b4e91 DH |
349 | /** |
350 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
351 | * @name: a pointer to a string containing the name of the file to create. | |
352 | * @mode: the permission that the file should have. | |
353 | * @parent: a pointer to the parent dentry for this file. This should be a | |
354 | * directory dentry if set. If this parameter is NULL, then the | |
355 | * file will be created in the root of the debugfs filesystem. | |
356 | * @data: a pointer to something that the caller will want to get to later | |
357 | * on. The inode.i_private pointer will point to this value on | |
358 | * the open() call. | |
359 | * @fops: a pointer to a struct file_operations that should be used for | |
360 | * this file. | |
361 | * @file_size: initial file size | |
362 | * | |
363 | * This is the basic "create a file" function for debugfs. It allows for a | |
364 | * wide range of flexibility in creating a file, or a directory (if you want | |
365 | * to create a directory, the debugfs_create_dir() function is | |
366 | * recommended to be used instead.) | |
367 | * | |
368 | * This function will return a pointer to a dentry if it succeeds. This | |
369 | * pointer must be passed to the debugfs_remove() function when the file is | |
370 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
371 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
372 | * | |
373 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
374 | * returned. | |
375 | */ | |
376 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
377 | struct dentry *parent, void *data, | |
378 | const struct file_operations *fops, | |
379 | loff_t file_size) | |
380 | { | |
381 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
382 | ||
383 | if (de) | |
384 | de->d_inode->i_size = file_size; | |
385 | return de; | |
386 | } | |
387 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
388 | ||
1da177e4 LT |
389 | /** |
390 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
391 | * @name: a pointer to a string containing the name of the directory to |
392 | * create. | |
393 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 394 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
395 | * directory will be created in the root of the debugfs filesystem. |
396 | * | |
397 | * This function creates a directory in debugfs with the given name. | |
398 | * | |
399 | * This function will return a pointer to a dentry if it succeeds. This | |
400 | * pointer must be passed to the debugfs_remove() function when the file is | |
401 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 402 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 403 | * |
6468b3af | 404 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 405 | * returned. |
1da177e4 LT |
406 | */ |
407 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
408 | { | |
ad5abd5b | 409 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 410 | struct inode *inode; |
ad5abd5b AV |
411 | |
412 | if (IS_ERR(dentry)) | |
413 | return NULL; | |
414 | ||
edac65ea | 415 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 416 | if (unlikely(!inode)) |
5233e311 | 417 | return failed_creating(dentry); |
680b3024 | 418 | |
edac65ea AV |
419 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
420 | inode->i_op = &simple_dir_inode_operations; | |
421 | inode->i_fop = &simple_dir_operations; | |
422 | ||
423 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
424 | inc_nlink(inode); | |
680b3024 | 425 | d_instantiate(dentry, inode); |
680b3024 AV |
426 | inc_nlink(dentry->d_parent->d_inode); |
427 | fsnotify_mkdir(dentry->d_parent->d_inode, dentry); | |
5233e311 | 428 | return end_creating(dentry); |
1da177e4 LT |
429 | } |
430 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
431 | ||
77b3da6e AV |
432 | /** |
433 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
434 | * @name: a pointer to a string containing the name of the file to create. | |
435 | * @parent: a pointer to the parent dentry for this file. This should be a | |
436 | * directory dentry if set. If this parameter is NULL, then the | |
437 | * file will be created in the root of the debugfs filesystem. | |
438 | * @f: function to be called when pathname resolution steps on that one. | |
439 | * @data: opaque argument to pass to f(). | |
440 | * | |
441 | * @f should return what ->d_automount() would. | |
442 | */ | |
443 | struct dentry *debugfs_create_automount(const char *name, | |
444 | struct dentry *parent, | |
445 | struct vfsmount *(*f)(void *), | |
446 | void *data) | |
447 | { | |
448 | struct dentry *dentry = start_creating(name, parent); | |
449 | struct inode *inode; | |
450 | ||
451 | if (IS_ERR(dentry)) | |
452 | return NULL; | |
453 | ||
454 | inode = debugfs_get_inode(dentry->d_sb); | |
455 | if (unlikely(!inode)) | |
456 | return failed_creating(dentry); | |
457 | ||
458 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; | |
459 | inode->i_flags |= S_AUTOMOUNT; | |
460 | inode->i_private = data; | |
461 | dentry->d_fsdata = (void *)f; | |
462 | d_instantiate(dentry, inode); | |
463 | return end_creating(dentry); | |
464 | } | |
465 | EXPORT_SYMBOL(debugfs_create_automount); | |
466 | ||
66f54963 PO |
467 | /** |
468 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
469 | * @name: a pointer to a string containing the name of the symbolic link to | |
470 | * create. | |
471 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 472 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
473 | * then the symbolic link will be created in the root of the debugfs |
474 | * filesystem. | |
475 | * @target: a pointer to a string containing the path to the target of the | |
476 | * symbolic link. | |
477 | * | |
478 | * This function creates a symbolic link with the given name in debugfs that | |
479 | * links to the given target path. | |
480 | * | |
481 | * This function will return a pointer to a dentry if it succeeds. This | |
482 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
483 | * link is to be removed (no automatic cleanup happens if your module is | |
484 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
485 | * returned. | |
486 | * | |
487 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 488 | * returned. |
66f54963 PO |
489 | */ |
490 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
491 | const char *target) | |
492 | { | |
ad5abd5b | 493 | struct dentry *dentry; |
680b3024 AV |
494 | struct inode *inode; |
495 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 PO |
496 | if (!link) |
497 | return NULL; | |
498 | ||
ad5abd5b | 499 | dentry = start_creating(name, parent); |
ad5abd5b | 500 | if (IS_ERR(dentry)) { |
66f54963 | 501 | kfree(link); |
ad5abd5b AV |
502 | return NULL; |
503 | } | |
504 | ||
edac65ea | 505 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 506 | if (unlikely(!inode)) { |
ad5abd5b | 507 | kfree(link); |
5233e311 | 508 | return failed_creating(dentry); |
680b3024 | 509 | } |
edac65ea AV |
510 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
511 | inode->i_op = &debugfs_link_operations; | |
512 | inode->i_private = link; | |
680b3024 | 513 | d_instantiate(dentry, inode); |
5233e311 | 514 | return end_creating(dentry); |
66f54963 PO |
515 | } |
516 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
517 | ||
25d41d84 | 518 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
519 | { |
520 | int ret = 0; | |
521 | ||
522 | if (debugfs_positive(dentry)) { | |
0db59e59 AV |
523 | dget(dentry); |
524 | if (S_ISDIR(dentry->d_inode->i_mode)) | |
525 | ret = simple_rmdir(parent->d_inode, dentry); | |
526 | else | |
527 | simple_unlink(parent->d_inode, dentry); | |
528 | if (!ret) | |
529 | d_delete(dentry); | |
530 | dput(dentry); | |
9505e637 | 531 | } |
25d41d84 | 532 | return ret; |
9505e637 HS |
533 | } |
534 | ||
1da177e4 LT |
535 | /** |
536 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 LT |
537 | * @dentry: a pointer to a the dentry of the file or directory to be |
538 | * removed. | |
539 | * | |
540 | * This function removes a file or directory in debugfs that was previously | |
541 | * created with a call to another debugfs function (like | |
5a65980e | 542 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
543 | * |
544 | * This function is required to be called in order for the file to be | |
545 | * removed, no automatic cleanup of files will happen when a module is | |
546 | * removed, you are responsible here. | |
547 | */ | |
548 | void debugfs_remove(struct dentry *dentry) | |
549 | { | |
550 | struct dentry *parent; | |
25d41d84 JK |
551 | int ret; |
552 | ||
a59d6293 | 553 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
554 | return; |
555 | ||
556 | parent = dentry->d_parent; | |
557 | if (!parent || !parent->d_inode) | |
558 | return; | |
559 | ||
1b1dcc1b | 560 | mutex_lock(&parent->d_inode->i_mutex); |
25d41d84 | 561 | ret = __debugfs_remove(dentry, parent); |
9505e637 | 562 | mutex_unlock(&parent->d_inode->i_mutex); |
25d41d84 JK |
563 | if (!ret) |
564 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
565 | } |
566 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
567 | ||
568 | /** | |
569 | * debugfs_remove_recursive - recursively removes a directory | |
570 | * @dentry: a pointer to a the dentry of the directory to be removed. | |
571 | * | |
572 | * This function recursively removes a directory tree in debugfs that | |
573 | * was previously created with a call to another debugfs function | |
574 | * (like debugfs_create_file() or variants thereof.) | |
575 | * | |
576 | * This function is required to be called in order for the file to be | |
577 | * removed, no automatic cleanup of files will happen when a module is | |
578 | * removed, you are responsible here. | |
579 | */ | |
580 | void debugfs_remove_recursive(struct dentry *dentry) | |
581 | { | |
485d4402 | 582 | struct dentry *child, *parent; |
9505e637 | 583 | |
a59d6293 | 584 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
585 | return; |
586 | ||
587 | parent = dentry->d_parent; | |
588 | if (!parent || !parent->d_inode) | |
589 | return; | |
590 | ||
591 | parent = dentry; | |
776164c1 | 592 | down: |
9505e637 | 593 | mutex_lock(&parent->d_inode->i_mutex); |
485d4402 SR |
594 | loop: |
595 | /* | |
596 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
597 | * lock, the child can be unlinked and set to be freed which can | |
598 | * use the d_u.d_child as the rcu head and corrupt this list. | |
599 | */ | |
600 | spin_lock(&parent->d_lock); | |
946e51f2 | 601 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
776164c1 ON |
602 | if (!debugfs_positive(child)) |
603 | continue; | |
9505e637 | 604 | |
776164c1 | 605 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 606 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 607 | spin_unlock(&parent->d_lock); |
9505e637 HS |
608 | mutex_unlock(&parent->d_inode->i_mutex); |
609 | parent = child; | |
776164c1 | 610 | goto down; |
1da177e4 | 611 | } |
485d4402 SR |
612 | |
613 | spin_unlock(&parent->d_lock); | |
614 | ||
776164c1 ON |
615 | if (!__debugfs_remove(child, parent)) |
616 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
617 | |
618 | /* | |
619 | * The parent->d_lock protects agaist child from unlinking | |
620 | * from d_subdirs. When releasing the parent->d_lock we can | |
621 | * no longer trust that the next pointer is valid. | |
622 | * Restart the loop. We'll skip this one with the | |
623 | * debugfs_positive() check. | |
624 | */ | |
625 | goto loop; | |
1da177e4 | 626 | } |
485d4402 | 627 | spin_unlock(&parent->d_lock); |
9505e637 | 628 | |
776164c1 ON |
629 | mutex_unlock(&parent->d_inode->i_mutex); |
630 | child = parent; | |
631 | parent = parent->d_parent; | |
9505e637 | 632 | mutex_lock(&parent->d_inode->i_mutex); |
776164c1 | 633 | |
485d4402 SR |
634 | if (child != dentry) |
635 | /* go up */ | |
636 | goto loop; | |
776164c1 ON |
637 | |
638 | if (!__debugfs_remove(child, parent)) | |
639 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1b1dcc1b | 640 | mutex_unlock(&parent->d_inode->i_mutex); |
1da177e4 | 641 | } |
9505e637 | 642 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 643 | |
cfc94cdf JK |
644 | /** |
645 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
646 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
647 | * should be a directory dentry. | |
648 | * @old_dentry: dentry of an object to be renamed. | |
649 | * @new_dir: a pointer to the parent dentry where the object should be | |
650 | * moved. This should be a directory dentry. | |
651 | * @new_name: a pointer to a string containing the target name. | |
652 | * | |
653 | * This function renames a file/directory in debugfs. The target must not | |
654 | * exist for rename to succeed. | |
655 | * | |
656 | * This function will return a pointer to old_dentry (which is updated to | |
657 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
658 | * returned. | |
659 | * | |
660 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
661 | * returned. | |
662 | */ | |
663 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
664 | struct dentry *new_dir, const char *new_name) | |
665 | { | |
666 | int error; | |
667 | struct dentry *dentry = NULL, *trap; | |
668 | const char *old_name; | |
669 | ||
670 | trap = lock_rename(new_dir, old_dir); | |
671 | /* Source or destination directories don't exist? */ | |
672 | if (!old_dir->d_inode || !new_dir->d_inode) | |
673 | goto exit; | |
674 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
675 | if (!old_dentry->d_inode || old_dentry == trap || | |
676 | d_mountpoint(old_dentry)) | |
677 | goto exit; | |
678 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
679 | /* Lookup failed, cyclic rename or target exists? */ | |
680 | if (IS_ERR(dentry) || dentry == trap || dentry->d_inode) | |
681 | goto exit; | |
682 | ||
683 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); | |
684 | ||
685 | error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, | |
686 | dentry); | |
687 | if (error) { | |
688 | fsnotify_oldname_free(old_name); | |
689 | goto exit; | |
690 | } | |
691 | d_move(old_dentry, dentry); | |
692 | fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name, | |
e36cb0b8 | 693 | d_is_dir(old_dentry), |
5a190ae6 | 694 | NULL, old_dentry); |
cfc94cdf JK |
695 | fsnotify_oldname_free(old_name); |
696 | unlock_rename(new_dir, old_dir); | |
697 | dput(dentry); | |
698 | return old_dentry; | |
699 | exit: | |
700 | if (dentry && !IS_ERR(dentry)) | |
701 | dput(dentry); | |
702 | unlock_rename(new_dir, old_dir); | |
703 | return NULL; | |
704 | } | |
705 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
706 | ||
c0f92ba9 FW |
707 | /** |
708 | * debugfs_initialized - Tells whether debugfs has been registered | |
709 | */ | |
710 | bool debugfs_initialized(void) | |
711 | { | |
712 | return debugfs_registered; | |
713 | } | |
714 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
715 | ||
716 | ||
191e186b | 717 | static struct kobject *debug_kobj; |
1da177e4 LT |
718 | |
719 | static int __init debugfs_init(void) | |
720 | { | |
721 | int retval; | |
722 | ||
0ff21e46 | 723 | debug_kobj = kobject_create_and_add("debug", kernel_kobj); |
191e186b GKH |
724 | if (!debug_kobj) |
725 | return -EINVAL; | |
1da177e4 LT |
726 | |
727 | retval = register_filesystem(&debug_fs_type); | |
728 | if (retval) | |
197b12d6 | 729 | kobject_put(debug_kobj); |
c0f92ba9 FW |
730 | else |
731 | debugfs_registered = true; | |
732 | ||
1da177e4 LT |
733 | return retval; |
734 | } | |
1da177e4 | 735 | core_initcall(debugfs_init); |
1da177e4 | 736 |