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 | |
f4ae40a6 | 37 | static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev, |
d3a3b0ad MD |
38 | void *data, const struct file_operations *fops) |
39 | ||
1da177e4 LT |
40 | { |
41 | struct inode *inode = new_inode(sb); | |
42 | ||
43 | if (inode) { | |
85fe4025 | 44 | inode->i_ino = get_next_ino(); |
1da177e4 | 45 | inode->i_mode = mode; |
1da177e4 LT |
46 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
47 | switch (mode & S_IFMT) { | |
48 | default: | |
49 | init_special_inode(inode, mode, dev); | |
50 | break; | |
51 | case S_IFREG: | |
d3a3b0ad MD |
52 | inode->i_fop = fops ? fops : &debugfs_file_operations; |
53 | inode->i_private = data; | |
1da177e4 | 54 | break; |
66f54963 PO |
55 | case S_IFLNK: |
56 | inode->i_op = &debugfs_link_operations; | |
d3a3b0ad | 57 | inode->i_private = data; |
66f54963 | 58 | break; |
1da177e4 LT |
59 | case S_IFDIR: |
60 | inode->i_op = &simple_dir_inode_operations; | |
ac481d6c | 61 | inode->i_fop = &simple_dir_operations; |
1da177e4 | 62 | |
bafb232e MD |
63 | /* directory inodes start off with i_nlink == 2 |
64 | * (for "." entry) */ | |
d8c76e6f | 65 | inc_nlink(inode); |
1da177e4 LT |
66 | break; |
67 | } | |
68 | } | |
88e412ea | 69 | return inode; |
1da177e4 LT |
70 | } |
71 | ||
72 | /* SMP-safe */ | |
73 | static int debugfs_mknod(struct inode *dir, struct dentry *dentry, | |
f4ae40a6 | 74 | umode_t mode, dev_t dev, void *data, |
d3a3b0ad | 75 | const struct file_operations *fops) |
1da177e4 | 76 | { |
71601e2b | 77 | struct inode *inode; |
1da177e4 LT |
78 | int error = -EPERM; |
79 | ||
80 | if (dentry->d_inode) | |
81 | return -EEXIST; | |
82 | ||
d3a3b0ad | 83 | inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops); |
1da177e4 LT |
84 | if (inode) { |
85 | d_instantiate(dentry, inode); | |
86 | dget(dentry); | |
87 | error = 0; | |
88 | } | |
89 | return error; | |
90 | } | |
91 | ||
ac481d6c | 92 | static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) |
1da177e4 LT |
93 | { |
94 | int res; | |
95 | ||
96 | mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR; | |
ac481d6c | 97 | res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL); |
4f36557f | 98 | if (!res) { |
d8c76e6f | 99 | inc_nlink(dir); |
4f36557f MD |
100 | fsnotify_mkdir(dir, dentry); |
101 | } | |
1da177e4 LT |
102 | return res; |
103 | } | |
104 | ||
f4ae40a6 | 105 | static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode, |
ac481d6c | 106 | void *data) |
66f54963 PO |
107 | { |
108 | mode = (mode & S_IALLUGO) | S_IFLNK; | |
ac481d6c | 109 | return debugfs_mknod(dir, dentry, mode, 0, data, NULL); |
66f54963 PO |
110 | } |
111 | ||
f4ae40a6 | 112 | static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, |
d3a3b0ad | 113 | void *data, const struct file_operations *fops) |
1da177e4 | 114 | { |
4f36557f MD |
115 | int res; |
116 | ||
1da177e4 | 117 | mode = (mode & S_IALLUGO) | S_IFREG; |
d3a3b0ad | 118 | res = debugfs_mknod(dir, dentry, mode, 0, data, fops); |
4f36557f MD |
119 | if (!res) |
120 | fsnotify_create(dir, dentry); | |
121 | return res; | |
1da177e4 LT |
122 | } |
123 | ||
124 | static inline int debugfs_positive(struct dentry *dentry) | |
125 | { | |
126 | return dentry->d_inode && !d_unhashed(dentry); | |
127 | } | |
128 | ||
d6e48686 | 129 | struct debugfs_mount_opts { |
7dc05881 EB |
130 | kuid_t uid; |
131 | kgid_t gid; | |
d6e48686 LN |
132 | umode_t mode; |
133 | }; | |
134 | ||
135 | enum { | |
136 | Opt_uid, | |
137 | Opt_gid, | |
138 | Opt_mode, | |
139 | Opt_err | |
140 | }; | |
141 | ||
142 | static const match_table_t tokens = { | |
143 | {Opt_uid, "uid=%u"}, | |
144 | {Opt_gid, "gid=%u"}, | |
145 | {Opt_mode, "mode=%o"}, | |
146 | {Opt_err, NULL} | |
147 | }; | |
148 | ||
149 | struct debugfs_fs_info { | |
150 | struct debugfs_mount_opts mount_opts; | |
151 | }; | |
152 | ||
153 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
154 | { | |
155 | substring_t args[MAX_OPT_ARGS]; | |
156 | int option; | |
157 | int token; | |
7dc05881 EB |
158 | kuid_t uid; |
159 | kgid_t gid; | |
d6e48686 LN |
160 | char *p; |
161 | ||
162 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
163 | ||
164 | while ((p = strsep(&data, ",")) != NULL) { | |
165 | if (!*p) | |
166 | continue; | |
167 | ||
168 | token = match_token(p, tokens, args); | |
169 | switch (token) { | |
170 | case Opt_uid: | |
171 | if (match_int(&args[0], &option)) | |
172 | return -EINVAL; | |
7dc05881 EB |
173 | uid = make_kuid(current_user_ns(), option); |
174 | if (!uid_valid(uid)) | |
175 | return -EINVAL; | |
176 | opts->uid = uid; | |
d6e48686 LN |
177 | break; |
178 | case Opt_gid: | |
f1688e04 | 179 | if (match_int(&args[0], &option)) |
d6e48686 | 180 | return -EINVAL; |
7dc05881 EB |
181 | gid = make_kgid(current_user_ns(), option); |
182 | if (!gid_valid(gid)) | |
183 | return -EINVAL; | |
184 | opts->gid = gid; | |
d6e48686 LN |
185 | break; |
186 | case Opt_mode: | |
187 | if (match_octal(&args[0], &option)) | |
188 | return -EINVAL; | |
189 | opts->mode = option & S_IALLUGO; | |
190 | break; | |
191 | /* | |
192 | * We might like to report bad mount options here; | |
193 | * but traditionally debugfs has ignored all mount options | |
194 | */ | |
195 | } | |
196 | } | |
197 | ||
198 | return 0; | |
199 | } | |
200 | ||
201 | static int debugfs_apply_options(struct super_block *sb) | |
202 | { | |
203 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
204 | struct inode *inode = sb->s_root->d_inode; | |
205 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
206 | ||
207 | inode->i_mode &= ~S_IALLUGO; | |
208 | inode->i_mode |= opts->mode; | |
209 | ||
210 | inode->i_uid = opts->uid; | |
211 | inode->i_gid = opts->gid; | |
212 | ||
213 | return 0; | |
214 | } | |
215 | ||
216 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
217 | { | |
218 | int err; | |
219 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
220 | ||
02b9984d | 221 | sync_filesystem(sb); |
d6e48686 LN |
222 | err = debugfs_parse_options(data, &fsi->mount_opts); |
223 | if (err) | |
224 | goto fail; | |
225 | ||
226 | debugfs_apply_options(sb); | |
227 | ||
228 | fail: | |
229 | return err; | |
230 | } | |
231 | ||
232 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
233 | { | |
234 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
235 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
236 | ||
7dc05881 EB |
237 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
238 | seq_printf(m, ",uid=%u", | |
239 | from_kuid_munged(&init_user_ns, opts->uid)); | |
240 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
241 | seq_printf(m, ",gid=%u", | |
242 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
243 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
244 | seq_printf(m, ",mode=%o", opts->mode); | |
245 | ||
246 | return 0; | |
247 | } | |
248 | ||
249 | static const struct super_operations debugfs_super_operations = { | |
250 | .statfs = simple_statfs, | |
251 | .remount_fs = debugfs_remount, | |
252 | .show_options = debugfs_show_options, | |
253 | }; | |
254 | ||
1da177e4 LT |
255 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
256 | { | |
257 | static struct tree_descr debug_files[] = {{""}}; | |
d6e48686 LN |
258 | struct debugfs_fs_info *fsi; |
259 | int err; | |
260 | ||
261 | save_mount_options(sb, data); | |
262 | ||
263 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); | |
264 | sb->s_fs_info = fsi; | |
265 | if (!fsi) { | |
266 | err = -ENOMEM; | |
267 | goto fail; | |
268 | } | |
269 | ||
270 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
271 | if (err) | |
272 | goto fail; | |
273 | ||
274 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
275 | if (err) | |
276 | goto fail; | |
277 | ||
278 | sb->s_op = &debugfs_super_operations; | |
279 | ||
280 | debugfs_apply_options(sb); | |
281 | ||
282 | return 0; | |
1da177e4 | 283 | |
d6e48686 LN |
284 | fail: |
285 | kfree(fsi); | |
286 | sb->s_fs_info = NULL; | |
287 | return err; | |
1da177e4 LT |
288 | } |
289 | ||
fc14f2fe | 290 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 291 | int flags, const char *dev_name, |
fc14f2fe | 292 | void *data) |
1da177e4 | 293 | { |
fc14f2fe | 294 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
295 | } |
296 | ||
297 | static struct file_system_type debug_fs_type = { | |
298 | .owner = THIS_MODULE, | |
299 | .name = "debugfs", | |
fc14f2fe | 300 | .mount = debug_mount, |
1da177e4 LT |
301 | .kill_sb = kill_litter_super, |
302 | }; | |
7f78e035 | 303 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 304 | |
3cd52ab6 CW |
305 | static struct dentry *__create_file(const char *name, umode_t mode, |
306 | struct dentry *parent, void *data, | |
307 | const struct file_operations *fops) | |
1da177e4 | 308 | { |
cfa57c11 AV |
309 | struct dentry *dentry = NULL; |
310 | int error; | |
311 | ||
312 | pr_debug("debugfs: creating file '%s'\n",name); | |
313 | ||
314 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, | |
315 | &debugfs_mount_count); | |
316 | if (error) | |
317 | goto exit; | |
1da177e4 LT |
318 | |
319 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 320 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
321 | * block. A pointer to that is in the struct vfsmount that we |
322 | * have around. | |
323 | */ | |
ef52c75e | 324 | if (!parent) |
4c1d5a64 | 325 | parent = debugfs_mount->mnt_root; |
1da177e4 | 326 | |
1b1dcc1b | 327 | mutex_lock(&parent->d_inode->i_mutex); |
cfa57c11 AV |
328 | dentry = lookup_one_len(name, parent, strlen(name)); |
329 | if (!IS_ERR(dentry)) { | |
66f54963 PO |
330 | switch (mode & S_IFMT) { |
331 | case S_IFDIR: | |
ac481d6c | 332 | error = debugfs_mkdir(parent->d_inode, dentry, mode); |
88e412ea | 333 | |
66f54963 PO |
334 | break; |
335 | case S_IFLNK: | |
cfa57c11 | 336 | error = debugfs_link(parent->d_inode, dentry, mode, |
ac481d6c | 337 | data); |
66f54963 PO |
338 | break; |
339 | default: | |
cfa57c11 | 340 | error = debugfs_create(parent->d_inode, dentry, mode, |
d3a3b0ad | 341 | data, fops); |
66f54963 PO |
342 | break; |
343 | } | |
cfa57c11 | 344 | dput(dentry); |
1da177e4 | 345 | } else |
cfa57c11 | 346 | error = PTR_ERR(dentry); |
1b1dcc1b | 347 | mutex_unlock(&parent->d_inode->i_mutex); |
1da177e4 | 348 | |
c3b1a350 AV |
349 | if (error) { |
350 | dentry = NULL; | |
351 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
352 | } | |
353 | exit: | |
354 | return dentry; | |
355 | } | |
356 | ||
1da177e4 LT |
357 | /** |
358 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 359 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 360 | * @mode: the permission that the file should have. |
1da177e4 | 361 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 362 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
363 | * file will be created in the root of the debugfs filesystem. |
364 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 365 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
366 | * the open() call. |
367 | * @fops: a pointer to a struct file_operations that should be used for | |
368 | * this file. | |
369 | * | |
370 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
371 | * wide range of flexibility in creating a file, or a directory (if you want |
372 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
373 | * recommended to be used instead.) |
374 | * | |
375 | * This function will return a pointer to a dentry if it succeeds. This | |
376 | * pointer must be passed to the debugfs_remove() function when the file is | |
377 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 378 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 379 | * |
6468b3af | 380 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 381 | * returned. |
1da177e4 | 382 | */ |
f4ae40a6 | 383 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 384 | struct dentry *parent, void *data, |
99ac48f5 | 385 | const struct file_operations *fops) |
1da177e4 | 386 | { |
c3b1a350 AV |
387 | switch (mode & S_IFMT) { |
388 | case S_IFREG: | |
389 | case 0: | |
390 | break; | |
391 | default: | |
392 | BUG(); | |
1da177e4 | 393 | } |
c3b1a350 AV |
394 | |
395 | return __create_file(name, mode, parent, data, fops); | |
1da177e4 LT |
396 | } |
397 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
398 | ||
399 | /** | |
400 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
401 | * @name: a pointer to a string containing the name of the directory to |
402 | * create. | |
403 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 404 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
405 | * directory will be created in the root of the debugfs filesystem. |
406 | * | |
407 | * This function creates a directory in debugfs with the given name. | |
408 | * | |
409 | * This function will return a pointer to a dentry if it succeeds. This | |
410 | * pointer must be passed to the debugfs_remove() function when the file is | |
411 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 412 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 413 | * |
6468b3af | 414 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 415 | * returned. |
1da177e4 LT |
416 | */ |
417 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
418 | { | |
c3b1a350 | 419 | return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO, |
1da177e4 LT |
420 | parent, NULL, NULL); |
421 | } | |
422 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
423 | ||
66f54963 PO |
424 | /** |
425 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
426 | * @name: a pointer to a string containing the name of the symbolic link to | |
427 | * create. | |
428 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 429 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
430 | * then the symbolic link will be created in the root of the debugfs |
431 | * filesystem. | |
432 | * @target: a pointer to a string containing the path to the target of the | |
433 | * symbolic link. | |
434 | * | |
435 | * This function creates a symbolic link with the given name in debugfs that | |
436 | * links to the given target path. | |
437 | * | |
438 | * This function will return a pointer to a dentry if it succeeds. This | |
439 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
440 | * link is to be removed (no automatic cleanup happens if your module is | |
441 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
442 | * returned. | |
443 | * | |
444 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 445 | * returned. |
66f54963 PO |
446 | */ |
447 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
448 | const char *target) | |
449 | { | |
450 | struct dentry *result; | |
451 | char *link; | |
452 | ||
453 | link = kstrdup(target, GFP_KERNEL); | |
454 | if (!link) | |
455 | return NULL; | |
456 | ||
c3b1a350 | 457 | result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL); |
66f54963 PO |
458 | if (!result) |
459 | kfree(link); | |
460 | return result; | |
461 | } | |
462 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
463 | ||
25d41d84 | 464 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
465 | { |
466 | int ret = 0; | |
467 | ||
468 | if (debugfs_positive(dentry)) { | |
469 | if (dentry->d_inode) { | |
470 | dget(dentry); | |
471 | switch (dentry->d_inode->i_mode & S_IFMT) { | |
472 | case S_IFDIR: | |
473 | ret = simple_rmdir(parent->d_inode, dentry); | |
474 | break; | |
475 | case S_IFLNK: | |
476 | kfree(dentry->d_inode->i_private); | |
477 | /* fall through */ | |
478 | default: | |
479 | simple_unlink(parent->d_inode, dentry); | |
480 | break; | |
481 | } | |
482 | if (!ret) | |
483 | d_delete(dentry); | |
484 | dput(dentry); | |
485 | } | |
486 | } | |
25d41d84 | 487 | return ret; |
9505e637 HS |
488 | } |
489 | ||
1da177e4 LT |
490 | /** |
491 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 LT |
492 | * @dentry: a pointer to a the dentry of the file or directory to be |
493 | * removed. | |
494 | * | |
495 | * This function removes a file or directory in debugfs that was previously | |
496 | * created with a call to another debugfs function (like | |
5a65980e | 497 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
498 | * |
499 | * This function is required to be called in order for the file to be | |
500 | * removed, no automatic cleanup of files will happen when a module is | |
501 | * removed, you are responsible here. | |
502 | */ | |
503 | void debugfs_remove(struct dentry *dentry) | |
504 | { | |
505 | struct dentry *parent; | |
25d41d84 JK |
506 | int ret; |
507 | ||
a59d6293 | 508 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
509 | return; |
510 | ||
511 | parent = dentry->d_parent; | |
512 | if (!parent || !parent->d_inode) | |
513 | return; | |
514 | ||
1b1dcc1b | 515 | mutex_lock(&parent->d_inode->i_mutex); |
25d41d84 | 516 | ret = __debugfs_remove(dentry, parent); |
9505e637 | 517 | mutex_unlock(&parent->d_inode->i_mutex); |
25d41d84 JK |
518 | if (!ret) |
519 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
520 | } |
521 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
522 | ||
523 | /** | |
524 | * debugfs_remove_recursive - recursively removes a directory | |
525 | * @dentry: a pointer to a the dentry of the directory to be removed. | |
526 | * | |
527 | * This function recursively removes a directory tree in debugfs that | |
528 | * was previously created with a call to another debugfs function | |
529 | * (like debugfs_create_file() or variants thereof.) | |
530 | * | |
531 | * This function is required to be called in order for the file to be | |
532 | * removed, no automatic cleanup of files will happen when a module is | |
533 | * removed, you are responsible here. | |
534 | */ | |
535 | void debugfs_remove_recursive(struct dentry *dentry) | |
536 | { | |
485d4402 | 537 | struct dentry *child, *parent; |
9505e637 | 538 | |
a59d6293 | 539 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
540 | return; |
541 | ||
542 | parent = dentry->d_parent; | |
543 | if (!parent || !parent->d_inode) | |
544 | return; | |
545 | ||
546 | parent = dentry; | |
776164c1 | 547 | down: |
9505e637 | 548 | mutex_lock(&parent->d_inode->i_mutex); |
485d4402 SR |
549 | loop: |
550 | /* | |
551 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
552 | * lock, the child can be unlinked and set to be freed which can | |
553 | * use the d_u.d_child as the rcu head and corrupt this list. | |
554 | */ | |
555 | spin_lock(&parent->d_lock); | |
556 | list_for_each_entry(child, &parent->d_subdirs, d_u.d_child) { | |
776164c1 ON |
557 | if (!debugfs_positive(child)) |
558 | continue; | |
9505e637 | 559 | |
776164c1 | 560 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 561 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 562 | spin_unlock(&parent->d_lock); |
9505e637 HS |
563 | mutex_unlock(&parent->d_inode->i_mutex); |
564 | parent = child; | |
776164c1 | 565 | goto down; |
1da177e4 | 566 | } |
485d4402 SR |
567 | |
568 | spin_unlock(&parent->d_lock); | |
569 | ||
776164c1 ON |
570 | if (!__debugfs_remove(child, parent)) |
571 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
572 | |
573 | /* | |
574 | * The parent->d_lock protects agaist child from unlinking | |
575 | * from d_subdirs. When releasing the parent->d_lock we can | |
576 | * no longer trust that the next pointer is valid. | |
577 | * Restart the loop. We'll skip this one with the | |
578 | * debugfs_positive() check. | |
579 | */ | |
580 | goto loop; | |
1da177e4 | 581 | } |
485d4402 | 582 | spin_unlock(&parent->d_lock); |
9505e637 | 583 | |
776164c1 ON |
584 | mutex_unlock(&parent->d_inode->i_mutex); |
585 | child = parent; | |
586 | parent = parent->d_parent; | |
9505e637 | 587 | mutex_lock(&parent->d_inode->i_mutex); |
776164c1 | 588 | |
485d4402 SR |
589 | if (child != dentry) |
590 | /* go up */ | |
591 | goto loop; | |
776164c1 ON |
592 | |
593 | if (!__debugfs_remove(child, parent)) | |
594 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1b1dcc1b | 595 | mutex_unlock(&parent->d_inode->i_mutex); |
1da177e4 | 596 | } |
9505e637 | 597 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 598 | |
cfc94cdf JK |
599 | /** |
600 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
601 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
602 | * should be a directory dentry. | |
603 | * @old_dentry: dentry of an object to be renamed. | |
604 | * @new_dir: a pointer to the parent dentry where the object should be | |
605 | * moved. This should be a directory dentry. | |
606 | * @new_name: a pointer to a string containing the target name. | |
607 | * | |
608 | * This function renames a file/directory in debugfs. The target must not | |
609 | * exist for rename to succeed. | |
610 | * | |
611 | * This function will return a pointer to old_dentry (which is updated to | |
612 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
613 | * returned. | |
614 | * | |
615 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
616 | * returned. | |
617 | */ | |
618 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
619 | struct dentry *new_dir, const char *new_name) | |
620 | { | |
621 | int error; | |
622 | struct dentry *dentry = NULL, *trap; | |
623 | const char *old_name; | |
624 | ||
625 | trap = lock_rename(new_dir, old_dir); | |
626 | /* Source or destination directories don't exist? */ | |
627 | if (!old_dir->d_inode || !new_dir->d_inode) | |
628 | goto exit; | |
629 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
630 | if (!old_dentry->d_inode || old_dentry == trap || | |
631 | d_mountpoint(old_dentry)) | |
632 | goto exit; | |
633 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
634 | /* Lookup failed, cyclic rename or target exists? */ | |
635 | if (IS_ERR(dentry) || dentry == trap || dentry->d_inode) | |
636 | goto exit; | |
637 | ||
638 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); | |
639 | ||
640 | error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode, | |
641 | dentry); | |
642 | if (error) { | |
643 | fsnotify_oldname_free(old_name); | |
644 | goto exit; | |
645 | } | |
646 | d_move(old_dentry, dentry); | |
647 | fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name, | |
123df294 | 648 | S_ISDIR(old_dentry->d_inode->i_mode), |
5a190ae6 | 649 | NULL, old_dentry); |
cfc94cdf JK |
650 | fsnotify_oldname_free(old_name); |
651 | unlock_rename(new_dir, old_dir); | |
652 | dput(dentry); | |
653 | return old_dentry; | |
654 | exit: | |
655 | if (dentry && !IS_ERR(dentry)) | |
656 | dput(dentry); | |
657 | unlock_rename(new_dir, old_dir); | |
658 | return NULL; | |
659 | } | |
660 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
661 | ||
c0f92ba9 FW |
662 | /** |
663 | * debugfs_initialized - Tells whether debugfs has been registered | |
664 | */ | |
665 | bool debugfs_initialized(void) | |
666 | { | |
667 | return debugfs_registered; | |
668 | } | |
669 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
670 | ||
671 | ||
191e186b | 672 | static struct kobject *debug_kobj; |
1da177e4 LT |
673 | |
674 | static int __init debugfs_init(void) | |
675 | { | |
676 | int retval; | |
677 | ||
0ff21e46 | 678 | debug_kobj = kobject_create_and_add("debug", kernel_kobj); |
191e186b GKH |
679 | if (!debug_kobj) |
680 | return -EINVAL; | |
1da177e4 LT |
681 | |
682 | retval = register_filesystem(&debug_fs_type); | |
683 | if (retval) | |
197b12d6 | 684 | kobject_put(debug_kobj); |
c0f92ba9 FW |
685 | else |
686 | debugfs_registered = true; | |
687 | ||
1da177e4 LT |
688 | return retval; |
689 | } | |
1da177e4 | 690 | core_initcall(debugfs_init); |
1da177e4 | 691 |