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. | |
e1511a84 | 12 | * See ./Documentation/core-api/kernel-api.rst for more details. |
1da177e4 LT |
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> |
9fd4dcec NS |
30 | #include <linux/srcu.h> |
31 | ||
32 | #include "internal.h" | |
1da177e4 | 33 | |
82aceae4 | 34 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 35 | |
9fd4dcec NS |
36 | DEFINE_SRCU(debugfs_srcu); |
37 | ||
1da177e4 LT |
38 | static struct vfsmount *debugfs_mount; |
39 | static int debugfs_mount_count; | |
c0f92ba9 | 40 | static bool debugfs_registered; |
1da177e4 | 41 | |
edac65ea | 42 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
43 | { |
44 | struct inode *inode = new_inode(sb); | |
1da177e4 | 45 | if (inode) { |
85fe4025 | 46 | inode->i_ino = get_next_ino(); |
1b48b530 | 47 | inode->i_atime = inode->i_mtime = |
c2050a45 | 48 | inode->i_ctime = current_time(inode); |
1da177e4 | 49 | } |
88e412ea | 50 | return inode; |
1da177e4 LT |
51 | } |
52 | ||
d6e48686 | 53 | struct debugfs_mount_opts { |
7dc05881 EB |
54 | kuid_t uid; |
55 | kgid_t gid; | |
d6e48686 LN |
56 | umode_t mode; |
57 | }; | |
58 | ||
59 | enum { | |
60 | Opt_uid, | |
61 | Opt_gid, | |
62 | Opt_mode, | |
63 | Opt_err | |
64 | }; | |
65 | ||
66 | static const match_table_t tokens = { | |
67 | {Opt_uid, "uid=%u"}, | |
68 | {Opt_gid, "gid=%u"}, | |
69 | {Opt_mode, "mode=%o"}, | |
70 | {Opt_err, NULL} | |
71 | }; | |
72 | ||
73 | struct debugfs_fs_info { | |
74 | struct debugfs_mount_opts mount_opts; | |
75 | }; | |
76 | ||
77 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
78 | { | |
79 | substring_t args[MAX_OPT_ARGS]; | |
80 | int option; | |
81 | int token; | |
7dc05881 EB |
82 | kuid_t uid; |
83 | kgid_t gid; | |
d6e48686 LN |
84 | char *p; |
85 | ||
86 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
87 | ||
88 | while ((p = strsep(&data, ",")) != NULL) { | |
89 | if (!*p) | |
90 | continue; | |
91 | ||
92 | token = match_token(p, tokens, args); | |
93 | switch (token) { | |
94 | case Opt_uid: | |
95 | if (match_int(&args[0], &option)) | |
96 | return -EINVAL; | |
7dc05881 EB |
97 | uid = make_kuid(current_user_ns(), option); |
98 | if (!uid_valid(uid)) | |
99 | return -EINVAL; | |
100 | opts->uid = uid; | |
d6e48686 LN |
101 | break; |
102 | case Opt_gid: | |
f1688e04 | 103 | if (match_int(&args[0], &option)) |
d6e48686 | 104 | return -EINVAL; |
7dc05881 EB |
105 | gid = make_kgid(current_user_ns(), option); |
106 | if (!gid_valid(gid)) | |
107 | return -EINVAL; | |
108 | opts->gid = gid; | |
d6e48686 LN |
109 | break; |
110 | case Opt_mode: | |
111 | if (match_octal(&args[0], &option)) | |
112 | return -EINVAL; | |
113 | opts->mode = option & S_IALLUGO; | |
114 | break; | |
115 | /* | |
116 | * We might like to report bad mount options here; | |
117 | * but traditionally debugfs has ignored all mount options | |
118 | */ | |
119 | } | |
120 | } | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int debugfs_apply_options(struct super_block *sb) | |
126 | { | |
127 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 128 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
129 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
130 | ||
131 | inode->i_mode &= ~S_IALLUGO; | |
132 | inode->i_mode |= opts->mode; | |
133 | ||
134 | inode->i_uid = opts->uid; | |
135 | inode->i_gid = opts->gid; | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
141 | { | |
142 | int err; | |
143 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
144 | ||
02b9984d | 145 | sync_filesystem(sb); |
d6e48686 LN |
146 | err = debugfs_parse_options(data, &fsi->mount_opts); |
147 | if (err) | |
148 | goto fail; | |
149 | ||
150 | debugfs_apply_options(sb); | |
151 | ||
152 | fail: | |
153 | return err; | |
154 | } | |
155 | ||
156 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
157 | { | |
158 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
159 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
160 | ||
7dc05881 EB |
161 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
162 | seq_printf(m, ",uid=%u", | |
163 | from_kuid_munged(&init_user_ns, opts->uid)); | |
164 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
165 | seq_printf(m, ",gid=%u", | |
166 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
167 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
168 | seq_printf(m, ",mode=%o", opts->mode); | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
0db59e59 AV |
173 | static void debugfs_evict_inode(struct inode *inode) |
174 | { | |
175 | truncate_inode_pages_final(&inode->i_data); | |
176 | clear_inode(inode); | |
177 | if (S_ISLNK(inode->i_mode)) | |
5723cb01 | 178 | kfree(inode->i_link); |
0db59e59 AV |
179 | } |
180 | ||
d6e48686 LN |
181 | static const struct super_operations debugfs_super_operations = { |
182 | .statfs = simple_statfs, | |
183 | .remount_fs = debugfs_remount, | |
184 | .show_options = debugfs_show_options, | |
0db59e59 | 185 | .evict_inode = debugfs_evict_inode, |
d6e48686 LN |
186 | }; |
187 | ||
77b3da6e AV |
188 | static struct vfsmount *debugfs_automount(struct path *path) |
189 | { | |
93faccbb EB |
190 | debugfs_automount_t f; |
191 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
192 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
193 | } |
194 | ||
195 | static const struct dentry_operations debugfs_dops = { | |
196 | .d_delete = always_delete_dentry, | |
197 | .d_automount = debugfs_automount, | |
198 | }; | |
199 | ||
1da177e4 LT |
200 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
201 | { | |
cda37124 | 202 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
203 | struct debugfs_fs_info *fsi; |
204 | int err; | |
205 | ||
d6e48686 LN |
206 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
207 | sb->s_fs_info = fsi; | |
208 | if (!fsi) { | |
209 | err = -ENOMEM; | |
210 | goto fail; | |
211 | } | |
212 | ||
213 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
214 | if (err) | |
215 | goto fail; | |
216 | ||
217 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
218 | if (err) | |
219 | goto fail; | |
220 | ||
221 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 222 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
223 | |
224 | debugfs_apply_options(sb); | |
225 | ||
226 | return 0; | |
1da177e4 | 227 | |
d6e48686 LN |
228 | fail: |
229 | kfree(fsi); | |
230 | sb->s_fs_info = NULL; | |
231 | return err; | |
1da177e4 LT |
232 | } |
233 | ||
fc14f2fe | 234 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 235 | int flags, const char *dev_name, |
fc14f2fe | 236 | void *data) |
1da177e4 | 237 | { |
fc14f2fe | 238 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
239 | } |
240 | ||
241 | static struct file_system_type debug_fs_type = { | |
242 | .owner = THIS_MODULE, | |
243 | .name = "debugfs", | |
fc14f2fe | 244 | .mount = debug_mount, |
1da177e4 LT |
245 | .kill_sb = kill_litter_super, |
246 | }; | |
7f78e035 | 247 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 248 | |
a7c5437b OS |
249 | /** |
250 | * debugfs_lookup() - look up an existing debugfs file | |
251 | * @name: a pointer to a string containing the name of the file to look up. | |
252 | * @parent: a pointer to the parent dentry of the file. | |
253 | * | |
254 | * This function will return a pointer to a dentry if it succeeds. If the file | |
255 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
256 | * dentry must be passed to dput() when it is no longer needed. | |
257 | * | |
258 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
259 | * returned. | |
260 | */ | |
261 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
262 | { | |
263 | struct dentry *dentry; | |
264 | ||
265 | if (IS_ERR(parent)) | |
266 | return NULL; | |
267 | ||
268 | if (!parent) | |
269 | parent = debugfs_mount->mnt_root; | |
270 | ||
271 | inode_lock(d_inode(parent)); | |
272 | dentry = lookup_one_len(name, parent, strlen(name)); | |
273 | inode_unlock(d_inode(parent)); | |
274 | ||
275 | if (IS_ERR(dentry)) | |
276 | return NULL; | |
277 | if (!d_really_is_positive(dentry)) { | |
278 | dput(dentry); | |
279 | return NULL; | |
280 | } | |
281 | return dentry; | |
282 | } | |
283 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
284 | ||
190afd81 | 285 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 286 | { |
190afd81 | 287 | struct dentry *dentry; |
cfa57c11 AV |
288 | int error; |
289 | ||
290 | pr_debug("debugfs: creating file '%s'\n",name); | |
291 | ||
c9e15f25 GK |
292 | if (IS_ERR(parent)) |
293 | return parent; | |
294 | ||
cfa57c11 AV |
295 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
296 | &debugfs_mount_count); | |
297 | if (error) | |
190afd81 | 298 | return ERR_PTR(error); |
1da177e4 LT |
299 | |
300 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 301 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
302 | * block. A pointer to that is in the struct vfsmount that we |
303 | * have around. | |
304 | */ | |
ef52c75e | 305 | if (!parent) |
4c1d5a64 | 306 | parent = debugfs_mount->mnt_root; |
1da177e4 | 307 | |
5955102c | 308 | inode_lock(d_inode(parent)); |
cfa57c11 | 309 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 310 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
cfa57c11 | 311 | dput(dentry); |
190afd81 AV |
312 | dentry = ERR_PTR(-EEXIST); |
313 | } | |
0ee9608c DB |
314 | |
315 | if (IS_ERR(dentry)) { | |
5955102c | 316 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
317 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
318 | } | |
319 | ||
190afd81 AV |
320 | return dentry; |
321 | } | |
322 | ||
5233e311 | 323 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 324 | { |
5955102c | 325 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 326 | dput(dentry); |
5233e311 AV |
327 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
328 | return NULL; | |
329 | } | |
1da177e4 | 330 | |
5233e311 AV |
331 | static struct dentry *end_creating(struct dentry *dentry) |
332 | { | |
5955102c | 333 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
334 | return dentry; |
335 | } | |
336 | ||
49d200de NS |
337 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
338 | struct dentry *parent, void *data, | |
339 | const struct file_operations *proxy_fops, | |
340 | const struct file_operations *real_fops) | |
341 | { | |
342 | struct dentry *dentry; | |
343 | struct inode *inode; | |
344 | ||
345 | if (!(mode & S_IFMT)) | |
346 | mode |= S_IFREG; | |
347 | BUG_ON(!S_ISREG(mode)); | |
348 | dentry = start_creating(name, parent); | |
349 | ||
350 | if (IS_ERR(dentry)) | |
351 | return NULL; | |
352 | ||
353 | inode = debugfs_get_inode(dentry->d_sb); | |
354 | if (unlikely(!inode)) | |
355 | return failed_creating(dentry); | |
356 | ||
357 | inode->i_mode = mode; | |
358 | inode->i_private = data; | |
359 | ||
360 | inode->i_fop = proxy_fops; | |
361 | dentry->d_fsdata = (void *)real_fops; | |
362 | ||
363 | d_instantiate(dentry, inode); | |
364 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
365 | return end_creating(dentry); | |
366 | } | |
367 | ||
1da177e4 LT |
368 | /** |
369 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 370 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 371 | * @mode: the permission that the file should have. |
1da177e4 | 372 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 373 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
374 | * file will be created in the root of the debugfs filesystem. |
375 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 376 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
377 | * the open() call. |
378 | * @fops: a pointer to a struct file_operations that should be used for | |
379 | * this file. | |
380 | * | |
381 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
382 | * wide range of flexibility in creating a file, or a directory (if you want |
383 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
384 | * recommended to be used instead.) |
385 | * | |
386 | * This function will return a pointer to a dentry if it succeeds. This | |
387 | * pointer must be passed to the debugfs_remove() function when the file is | |
388 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 389 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 390 | * |
6468b3af | 391 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 392 | * returned. |
1da177e4 | 393 | */ |
f4ae40a6 | 394 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 395 | struct dentry *parent, void *data, |
99ac48f5 | 396 | const struct file_operations *fops) |
1da177e4 | 397 | { |
680b3024 | 398 | |
49d200de NS |
399 | return __debugfs_create_file(name, mode, parent, data, |
400 | fops ? &debugfs_full_proxy_file_operations : | |
401 | &debugfs_noop_file_operations, | |
402 | fops); | |
403 | } | |
404 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 405 | |
c6468808 NS |
406 | /** |
407 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
408 | * @name: a pointer to a string containing the name of the file to create. | |
409 | * @mode: the permission that the file should have. | |
410 | * @parent: a pointer to the parent dentry for this file. This should be a | |
411 | * directory dentry if set. If this parameter is NULL, then the | |
412 | * file will be created in the root of the debugfs filesystem. | |
413 | * @data: a pointer to something that the caller will want to get to later | |
414 | * on. The inode.i_private pointer will point to this value on | |
415 | * the open() call. | |
416 | * @fops: a pointer to a struct file_operations that should be used for | |
417 | * this file. | |
418 | * | |
419 | * debugfs_create_file_unsafe() is completely analogous to | |
420 | * debugfs_create_file(), the only difference being that the fops | |
421 | * handed it will not get protected against file removals by the | |
422 | * debugfs core. | |
423 | * | |
424 | * It is your responsibility to protect your struct file_operation | |
425 | * methods against file removals by means of debugfs_use_file_start() | |
426 | * and debugfs_use_file_finish(). ->open() is still protected by | |
427 | * debugfs though. | |
428 | * | |
429 | * Any struct file_operations defined by means of | |
430 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
431 | * thus, may be used here. | |
432 | */ | |
49d200de NS |
433 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
434 | struct dentry *parent, void *data, | |
435 | const struct file_operations *fops) | |
436 | { | |
9fd4dcec | 437 | |
49d200de NS |
438 | return __debugfs_create_file(name, mode, parent, data, |
439 | fops ? &debugfs_open_proxy_file_operations : | |
440 | &debugfs_noop_file_operations, | |
441 | fops); | |
1da177e4 | 442 | } |
c6468808 | 443 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 444 | |
e59b4e91 DH |
445 | /** |
446 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
447 | * @name: a pointer to a string containing the name of the file to create. | |
448 | * @mode: the permission that the file should have. | |
449 | * @parent: a pointer to the parent dentry for this file. This should be a | |
450 | * directory dentry if set. If this parameter is NULL, then the | |
451 | * file will be created in the root of the debugfs filesystem. | |
452 | * @data: a pointer to something that the caller will want to get to later | |
453 | * on. The inode.i_private pointer will point to this value on | |
454 | * the open() call. | |
455 | * @fops: a pointer to a struct file_operations that should be used for | |
456 | * this file. | |
457 | * @file_size: initial file size | |
458 | * | |
459 | * This is the basic "create a file" function for debugfs. It allows for a | |
460 | * wide range of flexibility in creating a file, or a directory (if you want | |
461 | * to create a directory, the debugfs_create_dir() function is | |
462 | * recommended to be used instead.) | |
463 | * | |
464 | * This function will return a pointer to a dentry if it succeeds. This | |
465 | * pointer must be passed to the debugfs_remove() function when the file is | |
466 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
467 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
468 | * | |
469 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
470 | * returned. | |
471 | */ | |
472 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
473 | struct dentry *parent, void *data, | |
474 | const struct file_operations *fops, | |
475 | loff_t file_size) | |
476 | { | |
477 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
478 | ||
479 | if (de) | |
2b0143b5 | 480 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
481 | return de; |
482 | } | |
483 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
484 | ||
1da177e4 LT |
485 | /** |
486 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
487 | * @name: a pointer to a string containing the name of the directory to |
488 | * create. | |
489 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 490 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
491 | * directory will be created in the root of the debugfs filesystem. |
492 | * | |
493 | * This function creates a directory in debugfs with the given name. | |
494 | * | |
495 | * This function will return a pointer to a dentry if it succeeds. This | |
496 | * pointer must be passed to the debugfs_remove() function when the file is | |
497 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 498 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 499 | * |
6468b3af | 500 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 501 | * returned. |
1da177e4 LT |
502 | */ |
503 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
504 | { | |
ad5abd5b | 505 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 506 | struct inode *inode; |
ad5abd5b AV |
507 | |
508 | if (IS_ERR(dentry)) | |
509 | return NULL; | |
510 | ||
edac65ea | 511 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 512 | if (unlikely(!inode)) |
5233e311 | 513 | return failed_creating(dentry); |
680b3024 | 514 | |
edac65ea AV |
515 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
516 | inode->i_op = &simple_dir_inode_operations; | |
517 | inode->i_fop = &simple_dir_operations; | |
518 | ||
519 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
520 | inc_nlink(inode); | |
680b3024 | 521 | d_instantiate(dentry, inode); |
2b0143b5 DH |
522 | inc_nlink(d_inode(dentry->d_parent)); |
523 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 524 | return end_creating(dentry); |
1da177e4 LT |
525 | } |
526 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
527 | ||
77b3da6e AV |
528 | /** |
529 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
530 | * @name: a pointer to a string containing the name of the file to create. | |
531 | * @parent: a pointer to the parent dentry for this file. This should be a | |
532 | * directory dentry if set. If this parameter is NULL, then the | |
533 | * file will be created in the root of the debugfs filesystem. | |
534 | * @f: function to be called when pathname resolution steps on that one. | |
535 | * @data: opaque argument to pass to f(). | |
536 | * | |
537 | * @f should return what ->d_automount() would. | |
538 | */ | |
539 | struct dentry *debugfs_create_automount(const char *name, | |
540 | struct dentry *parent, | |
93faccbb | 541 | debugfs_automount_t f, |
77b3da6e AV |
542 | void *data) |
543 | { | |
544 | struct dentry *dentry = start_creating(name, parent); | |
545 | struct inode *inode; | |
546 | ||
547 | if (IS_ERR(dentry)) | |
548 | return NULL; | |
549 | ||
550 | inode = debugfs_get_inode(dentry->d_sb); | |
551 | if (unlikely(!inode)) | |
552 | return failed_creating(dentry); | |
553 | ||
87243deb | 554 | make_empty_dir_inode(inode); |
77b3da6e AV |
555 | inode->i_flags |= S_AUTOMOUNT; |
556 | inode->i_private = data; | |
557 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
558 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
559 | inc_nlink(inode); | |
77b3da6e | 560 | d_instantiate(dentry, inode); |
a8f324a4 RP |
561 | inc_nlink(d_inode(dentry->d_parent)); |
562 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
563 | return end_creating(dentry); |
564 | } | |
565 | EXPORT_SYMBOL(debugfs_create_automount); | |
566 | ||
66f54963 PO |
567 | /** |
568 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
569 | * @name: a pointer to a string containing the name of the symbolic link to | |
570 | * create. | |
571 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 572 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
573 | * then the symbolic link will be created in the root of the debugfs |
574 | * filesystem. | |
575 | * @target: a pointer to a string containing the path to the target of the | |
576 | * symbolic link. | |
577 | * | |
578 | * This function creates a symbolic link with the given name in debugfs that | |
579 | * links to the given target path. | |
580 | * | |
581 | * This function will return a pointer to a dentry if it succeeds. This | |
582 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
583 | * link is to be removed (no automatic cleanup happens if your module is | |
584 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
585 | * returned. | |
586 | * | |
587 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 588 | * returned. |
66f54963 PO |
589 | */ |
590 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
591 | const char *target) | |
592 | { | |
ad5abd5b | 593 | struct dentry *dentry; |
680b3024 AV |
594 | struct inode *inode; |
595 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 PO |
596 | if (!link) |
597 | return NULL; | |
598 | ||
ad5abd5b | 599 | dentry = start_creating(name, parent); |
ad5abd5b | 600 | if (IS_ERR(dentry)) { |
66f54963 | 601 | kfree(link); |
ad5abd5b AV |
602 | return NULL; |
603 | } | |
604 | ||
edac65ea | 605 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 606 | if (unlikely(!inode)) { |
ad5abd5b | 607 | kfree(link); |
5233e311 | 608 | return failed_creating(dentry); |
680b3024 | 609 | } |
edac65ea | 610 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5723cb01 AV |
611 | inode->i_op = &simple_symlink_inode_operations; |
612 | inode->i_link = link; | |
680b3024 | 613 | d_instantiate(dentry, inode); |
5233e311 | 614 | return end_creating(dentry); |
66f54963 PO |
615 | } |
616 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
617 | ||
25d41d84 | 618 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
619 | { |
620 | int ret = 0; | |
621 | ||
dc3f4198 | 622 | if (simple_positive(dentry)) { |
0db59e59 | 623 | dget(dentry); |
7ceab50c | 624 | if (d_is_dir(dentry)) |
2b0143b5 | 625 | ret = simple_rmdir(d_inode(parent), dentry); |
0db59e59 | 626 | else |
2b0143b5 | 627 | simple_unlink(d_inode(parent), dentry); |
0db59e59 AV |
628 | if (!ret) |
629 | d_delete(dentry); | |
630 | dput(dentry); | |
9505e637 | 631 | } |
25d41d84 | 632 | return ret; |
9505e637 HS |
633 | } |
634 | ||
1da177e4 LT |
635 | /** |
636 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 | 637 | * @dentry: a pointer to a the dentry of the file or directory to be |
398dc4ad UM |
638 | * removed. If this parameter is NULL or an error value, nothing |
639 | * will be done. | |
1da177e4 LT |
640 | * |
641 | * This function removes a file or directory in debugfs that was previously | |
642 | * created with a call to another debugfs function (like | |
5a65980e | 643 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
644 | * |
645 | * This function is required to be called in order for the file to be | |
646 | * removed, no automatic cleanup of files will happen when a module is | |
647 | * removed, you are responsible here. | |
648 | */ | |
649 | void debugfs_remove(struct dentry *dentry) | |
650 | { | |
651 | struct dentry *parent; | |
25d41d84 JK |
652 | int ret; |
653 | ||
a59d6293 | 654 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
655 | return; |
656 | ||
657 | parent = dentry->d_parent; | |
5955102c | 658 | inode_lock(d_inode(parent)); |
25d41d84 | 659 | ret = __debugfs_remove(dentry, parent); |
5955102c | 660 | inode_unlock(d_inode(parent)); |
25d41d84 JK |
661 | if (!ret) |
662 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
49d200de | 663 | |
9fd4dcec | 664 | synchronize_srcu(&debugfs_srcu); |
9505e637 HS |
665 | } |
666 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
667 | ||
668 | /** | |
669 | * debugfs_remove_recursive - recursively removes a directory | |
398dc4ad UM |
670 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
671 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
672 | * |
673 | * This function recursively removes a directory tree in debugfs that | |
674 | * was previously created with a call to another debugfs function | |
675 | * (like debugfs_create_file() or variants thereof.) | |
676 | * | |
677 | * This function is required to be called in order for the file to be | |
678 | * removed, no automatic cleanup of files will happen when a module is | |
679 | * removed, you are responsible here. | |
680 | */ | |
681 | void debugfs_remove_recursive(struct dentry *dentry) | |
682 | { | |
485d4402 | 683 | struct dentry *child, *parent; |
9505e637 | 684 | |
a59d6293 | 685 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
686 | return; |
687 | ||
9505e637 | 688 | parent = dentry; |
776164c1 | 689 | down: |
5955102c | 690 | inode_lock(d_inode(parent)); |
485d4402 SR |
691 | loop: |
692 | /* | |
693 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
694 | * lock, the child can be unlinked and set to be freed which can | |
695 | * use the d_u.d_child as the rcu head and corrupt this list. | |
696 | */ | |
697 | spin_lock(&parent->d_lock); | |
946e51f2 | 698 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 699 | if (!simple_positive(child)) |
776164c1 | 700 | continue; |
9505e637 | 701 | |
776164c1 | 702 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 703 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 704 | spin_unlock(&parent->d_lock); |
5955102c | 705 | inode_unlock(d_inode(parent)); |
9505e637 | 706 | parent = child; |
776164c1 | 707 | goto down; |
1da177e4 | 708 | } |
485d4402 SR |
709 | |
710 | spin_unlock(&parent->d_lock); | |
711 | ||
776164c1 ON |
712 | if (!__debugfs_remove(child, parent)) |
713 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
714 | |
715 | /* | |
716 | * The parent->d_lock protects agaist child from unlinking | |
717 | * from d_subdirs. When releasing the parent->d_lock we can | |
718 | * no longer trust that the next pointer is valid. | |
719 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 720 | * simple_positive() check. |
485d4402 SR |
721 | */ |
722 | goto loop; | |
1da177e4 | 723 | } |
485d4402 | 724 | spin_unlock(&parent->d_lock); |
9505e637 | 725 | |
5955102c | 726 | inode_unlock(d_inode(parent)); |
776164c1 ON |
727 | child = parent; |
728 | parent = parent->d_parent; | |
5955102c | 729 | inode_lock(d_inode(parent)); |
776164c1 | 730 | |
485d4402 SR |
731 | if (child != dentry) |
732 | /* go up */ | |
733 | goto loop; | |
776164c1 ON |
734 | |
735 | if (!__debugfs_remove(child, parent)) | |
736 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
5955102c | 737 | inode_unlock(d_inode(parent)); |
49d200de | 738 | |
9fd4dcec | 739 | synchronize_srcu(&debugfs_srcu); |
1da177e4 | 740 | } |
9505e637 | 741 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 742 | |
cfc94cdf JK |
743 | /** |
744 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
745 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
746 | * should be a directory dentry. | |
747 | * @old_dentry: dentry of an object to be renamed. | |
748 | * @new_dir: a pointer to the parent dentry where the object should be | |
749 | * moved. This should be a directory dentry. | |
750 | * @new_name: a pointer to a string containing the target name. | |
751 | * | |
752 | * This function renames a file/directory in debugfs. The target must not | |
753 | * exist for rename to succeed. | |
754 | * | |
755 | * This function will return a pointer to old_dentry (which is updated to | |
756 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
757 | * returned. | |
758 | * | |
759 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
760 | * returned. | |
761 | */ | |
762 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
763 | struct dentry *new_dir, const char *new_name) | |
764 | { | |
765 | int error; | |
766 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 767 | struct name_snapshot old_name; |
cfc94cdf JK |
768 | |
769 | trap = lock_rename(new_dir, old_dir); | |
770 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 771 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
772 | goto exit; |
773 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 774 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
775 | d_mountpoint(old_dentry)) |
776 | goto exit; | |
777 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
778 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 779 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
780 | goto exit; |
781 | ||
49d31c2f | 782 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 783 | |
2b0143b5 | 784 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
e0e0be8a | 785 | dentry, 0); |
cfc94cdf | 786 | if (error) { |
49d31c2f | 787 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
788 | goto exit; |
789 | } | |
790 | d_move(old_dentry, dentry); | |
49d31c2f | 791 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name, |
e36cb0b8 | 792 | d_is_dir(old_dentry), |
5a190ae6 | 793 | NULL, old_dentry); |
49d31c2f | 794 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
795 | unlock_rename(new_dir, old_dir); |
796 | dput(dentry); | |
797 | return old_dentry; | |
798 | exit: | |
799 | if (dentry && !IS_ERR(dentry)) | |
800 | dput(dentry); | |
801 | unlock_rename(new_dir, old_dir); | |
802 | return NULL; | |
803 | } | |
804 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
805 | ||
c0f92ba9 FW |
806 | /** |
807 | * debugfs_initialized - Tells whether debugfs has been registered | |
808 | */ | |
809 | bool debugfs_initialized(void) | |
810 | { | |
811 | return debugfs_registered; | |
812 | } | |
813 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
814 | ||
1da177e4 LT |
815 | static int __init debugfs_init(void) |
816 | { | |
817 | int retval; | |
818 | ||
f9bb4882 EB |
819 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
820 | if (retval) | |
821 | return retval; | |
1da177e4 LT |
822 | |
823 | retval = register_filesystem(&debug_fs_type); | |
824 | if (retval) | |
f9bb4882 | 825 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
826 | else |
827 | debugfs_registered = true; | |
828 | ||
1da177e4 LT |
829 | return retval; |
830 | } | |
1da177e4 | 831 | core_initcall(debugfs_init); |
1da177e4 | 832 |