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3bce94fd | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
bd33d12f | 3 | * inode.c - part of debugfs, a tiny little debug file system |
1da177e4 LT |
4 | * |
5 | * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com> | |
6 | * Copyright (C) 2004 IBM Inc. | |
7 | * | |
1da177e4 | 8 | * debugfs is for people to use instead of /proc or /sys. |
e1511a84 | 9 | * See ./Documentation/core-api/kernel-api.rst for more details. |
1da177e4 LT |
10 | */ |
11 | ||
1da177e4 LT |
12 | #include <linux/module.h> |
13 | #include <linux/fs.h> | |
14 | #include <linux/mount.h> | |
15 | #include <linux/pagemap.h> | |
16 | #include <linux/init.h> | |
4d8ebddc | 17 | #include <linux/kobject.h> |
1da177e4 LT |
18 | #include <linux/namei.h> |
19 | #include <linux/debugfs.h> | |
4f36557f | 20 | #include <linux/fsnotify.h> |
66f54963 | 21 | #include <linux/string.h> |
d6e48686 LN |
22 | #include <linux/seq_file.h> |
23 | #include <linux/parser.h> | |
92562927 | 24 | #include <linux/magic.h> |
5a0e3ad6 | 25 | #include <linux/slab.h> |
9fd4dcec NS |
26 | |
27 | #include "internal.h" | |
1da177e4 | 28 | |
82aceae4 | 29 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 30 | |
1da177e4 LT |
31 | static struct vfsmount *debugfs_mount; |
32 | static int debugfs_mount_count; | |
c0f92ba9 | 33 | static bool debugfs_registered; |
1da177e4 | 34 | |
edac65ea | 35 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
36 | { |
37 | struct inode *inode = new_inode(sb); | |
1da177e4 | 38 | if (inode) { |
85fe4025 | 39 | inode->i_ino = get_next_ino(); |
1b48b530 | 40 | inode->i_atime = inode->i_mtime = |
c2050a45 | 41 | inode->i_ctime = current_time(inode); |
1da177e4 | 42 | } |
88e412ea | 43 | return inode; |
1da177e4 LT |
44 | } |
45 | ||
d6e48686 | 46 | struct debugfs_mount_opts { |
7dc05881 EB |
47 | kuid_t uid; |
48 | kgid_t gid; | |
d6e48686 LN |
49 | umode_t mode; |
50 | }; | |
51 | ||
52 | enum { | |
53 | Opt_uid, | |
54 | Opt_gid, | |
55 | Opt_mode, | |
56 | Opt_err | |
57 | }; | |
58 | ||
59 | static const match_table_t tokens = { | |
60 | {Opt_uid, "uid=%u"}, | |
61 | {Opt_gid, "gid=%u"}, | |
62 | {Opt_mode, "mode=%o"}, | |
63 | {Opt_err, NULL} | |
64 | }; | |
65 | ||
66 | struct debugfs_fs_info { | |
67 | struct debugfs_mount_opts mount_opts; | |
68 | }; | |
69 | ||
70 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
71 | { | |
72 | substring_t args[MAX_OPT_ARGS]; | |
73 | int option; | |
74 | int token; | |
7dc05881 EB |
75 | kuid_t uid; |
76 | kgid_t gid; | |
d6e48686 LN |
77 | char *p; |
78 | ||
79 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
80 | ||
81 | while ((p = strsep(&data, ",")) != NULL) { | |
82 | if (!*p) | |
83 | continue; | |
84 | ||
85 | token = match_token(p, tokens, args); | |
86 | switch (token) { | |
87 | case Opt_uid: | |
88 | if (match_int(&args[0], &option)) | |
89 | return -EINVAL; | |
7dc05881 EB |
90 | uid = make_kuid(current_user_ns(), option); |
91 | if (!uid_valid(uid)) | |
92 | return -EINVAL; | |
93 | opts->uid = uid; | |
d6e48686 LN |
94 | break; |
95 | case Opt_gid: | |
f1688e04 | 96 | if (match_int(&args[0], &option)) |
d6e48686 | 97 | return -EINVAL; |
7dc05881 EB |
98 | gid = make_kgid(current_user_ns(), option); |
99 | if (!gid_valid(gid)) | |
100 | return -EINVAL; | |
101 | opts->gid = gid; | |
d6e48686 LN |
102 | break; |
103 | case Opt_mode: | |
104 | if (match_octal(&args[0], &option)) | |
105 | return -EINVAL; | |
106 | opts->mode = option & S_IALLUGO; | |
107 | break; | |
108 | /* | |
109 | * We might like to report bad mount options here; | |
110 | * but traditionally debugfs has ignored all mount options | |
111 | */ | |
112 | } | |
113 | } | |
114 | ||
115 | return 0; | |
116 | } | |
117 | ||
118 | static int debugfs_apply_options(struct super_block *sb) | |
119 | { | |
120 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 121 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
122 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
123 | ||
124 | inode->i_mode &= ~S_IALLUGO; | |
125 | inode->i_mode |= opts->mode; | |
126 | ||
127 | inode->i_uid = opts->uid; | |
128 | inode->i_gid = opts->gid; | |
129 | ||
130 | return 0; | |
131 | } | |
132 | ||
133 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
134 | { | |
135 | int err; | |
136 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
137 | ||
02b9984d | 138 | sync_filesystem(sb); |
d6e48686 LN |
139 | err = debugfs_parse_options(data, &fsi->mount_opts); |
140 | if (err) | |
141 | goto fail; | |
142 | ||
143 | debugfs_apply_options(sb); | |
144 | ||
145 | fail: | |
146 | return err; | |
147 | } | |
148 | ||
149 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
150 | { | |
151 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
152 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
153 | ||
7dc05881 EB |
154 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
155 | seq_printf(m, ",uid=%u", | |
156 | from_kuid_munged(&init_user_ns, opts->uid)); | |
157 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
158 | seq_printf(m, ",gid=%u", | |
159 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
160 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
161 | seq_printf(m, ",mode=%o", opts->mode); | |
162 | ||
163 | return 0; | |
164 | } | |
165 | ||
a6214e07 | 166 | static void debugfs_i_callback(struct rcu_head *head) |
0db59e59 | 167 | { |
a6214e07 | 168 | struct inode *inode = container_of(head, struct inode, i_rcu); |
0db59e59 | 169 | if (S_ISLNK(inode->i_mode)) |
5723cb01 | 170 | kfree(inode->i_link); |
a6214e07 AV |
171 | free_inode_nonrcu(inode); |
172 | } | |
173 | ||
174 | static void debugfs_destroy_inode(struct inode *inode) | |
175 | { | |
176 | call_rcu(&inode->i_rcu, debugfs_i_callback); | |
0db59e59 AV |
177 | } |
178 | ||
d6e48686 LN |
179 | static const struct super_operations debugfs_super_operations = { |
180 | .statfs = simple_statfs, | |
181 | .remount_fs = debugfs_remount, | |
182 | .show_options = debugfs_show_options, | |
a6214e07 | 183 | .destroy_inode = debugfs_destroy_inode, |
d6e48686 LN |
184 | }; |
185 | ||
7c8d4698 NS |
186 | static void debugfs_release_dentry(struct dentry *dentry) |
187 | { | |
7d39bc50 NS |
188 | void *fsd = dentry->d_fsdata; |
189 | ||
190 | if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) | |
191 | kfree(dentry->d_fsdata); | |
7c8d4698 NS |
192 | } |
193 | ||
77b3da6e AV |
194 | static struct vfsmount *debugfs_automount(struct path *path) |
195 | { | |
93faccbb EB |
196 | debugfs_automount_t f; |
197 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
198 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
199 | } |
200 | ||
201 | static const struct dentry_operations debugfs_dops = { | |
202 | .d_delete = always_delete_dentry, | |
7c8d4698 | 203 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
204 | .d_automount = debugfs_automount, |
205 | }; | |
206 | ||
1da177e4 LT |
207 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
208 | { | |
cda37124 | 209 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
210 | struct debugfs_fs_info *fsi; |
211 | int err; | |
212 | ||
d6e48686 LN |
213 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
214 | sb->s_fs_info = fsi; | |
215 | if (!fsi) { | |
216 | err = -ENOMEM; | |
217 | goto fail; | |
218 | } | |
219 | ||
220 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
221 | if (err) | |
222 | goto fail; | |
223 | ||
224 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
225 | if (err) | |
226 | goto fail; | |
227 | ||
228 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 229 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
230 | |
231 | debugfs_apply_options(sb); | |
232 | ||
233 | return 0; | |
1da177e4 | 234 | |
d6e48686 LN |
235 | fail: |
236 | kfree(fsi); | |
237 | sb->s_fs_info = NULL; | |
238 | return err; | |
1da177e4 LT |
239 | } |
240 | ||
fc14f2fe | 241 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 242 | int flags, const char *dev_name, |
fc14f2fe | 243 | void *data) |
1da177e4 | 244 | { |
fc14f2fe | 245 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
246 | } |
247 | ||
248 | static struct file_system_type debug_fs_type = { | |
249 | .owner = THIS_MODULE, | |
250 | .name = "debugfs", | |
fc14f2fe | 251 | .mount = debug_mount, |
1da177e4 LT |
252 | .kill_sb = kill_litter_super, |
253 | }; | |
7f78e035 | 254 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 255 | |
a7c5437b OS |
256 | /** |
257 | * debugfs_lookup() - look up an existing debugfs file | |
258 | * @name: a pointer to a string containing the name of the file to look up. | |
259 | * @parent: a pointer to the parent dentry of the file. | |
260 | * | |
261 | * This function will return a pointer to a dentry if it succeeds. If the file | |
262 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
263 | * dentry must be passed to dput() when it is no longer needed. | |
264 | * | |
265 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
266 | * returned. | |
267 | */ | |
268 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
269 | { | |
270 | struct dentry *dentry; | |
271 | ||
272 | if (IS_ERR(parent)) | |
273 | return NULL; | |
274 | ||
275 | if (!parent) | |
276 | parent = debugfs_mount->mnt_root; | |
277 | ||
278 | inode_lock(d_inode(parent)); | |
279 | dentry = lookup_one_len(name, parent, strlen(name)); | |
280 | inode_unlock(d_inode(parent)); | |
281 | ||
282 | if (IS_ERR(dentry)) | |
283 | return NULL; | |
284 | if (!d_really_is_positive(dentry)) { | |
285 | dput(dentry); | |
286 | return NULL; | |
287 | } | |
288 | return dentry; | |
289 | } | |
290 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
291 | ||
190afd81 | 292 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 293 | { |
190afd81 | 294 | struct dentry *dentry; |
cfa57c11 AV |
295 | int error; |
296 | ||
297 | pr_debug("debugfs: creating file '%s'\n",name); | |
298 | ||
c9e15f25 GK |
299 | if (IS_ERR(parent)) |
300 | return parent; | |
301 | ||
cfa57c11 AV |
302 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
303 | &debugfs_mount_count); | |
304 | if (error) | |
190afd81 | 305 | return ERR_PTR(error); |
1da177e4 LT |
306 | |
307 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 308 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
309 | * block. A pointer to that is in the struct vfsmount that we |
310 | * have around. | |
311 | */ | |
ef52c75e | 312 | if (!parent) |
4c1d5a64 | 313 | parent = debugfs_mount->mnt_root; |
1da177e4 | 314 | |
5955102c | 315 | inode_lock(d_inode(parent)); |
cfa57c11 | 316 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 317 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
cfa57c11 | 318 | dput(dentry); |
190afd81 AV |
319 | dentry = ERR_PTR(-EEXIST); |
320 | } | |
0ee9608c DB |
321 | |
322 | if (IS_ERR(dentry)) { | |
5955102c | 323 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
324 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
325 | } | |
326 | ||
190afd81 AV |
327 | return dentry; |
328 | } | |
329 | ||
5233e311 | 330 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 331 | { |
5955102c | 332 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 333 | dput(dentry); |
5233e311 AV |
334 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
335 | return NULL; | |
336 | } | |
1da177e4 | 337 | |
5233e311 AV |
338 | static struct dentry *end_creating(struct dentry *dentry) |
339 | { | |
5955102c | 340 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
341 | return dentry; |
342 | } | |
343 | ||
49d200de NS |
344 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
345 | struct dentry *parent, void *data, | |
346 | const struct file_operations *proxy_fops, | |
347 | const struct file_operations *real_fops) | |
348 | { | |
349 | struct dentry *dentry; | |
350 | struct inode *inode; | |
351 | ||
352 | if (!(mode & S_IFMT)) | |
353 | mode |= S_IFREG; | |
354 | BUG_ON(!S_ISREG(mode)); | |
355 | dentry = start_creating(name, parent); | |
356 | ||
7d39bc50 | 357 | if (IS_ERR(dentry)) |
49d200de NS |
358 | return NULL; |
359 | ||
360 | inode = debugfs_get_inode(dentry->d_sb); | |
7d39bc50 | 361 | if (unlikely(!inode)) |
49d200de NS |
362 | return failed_creating(dentry); |
363 | ||
364 | inode->i_mode = mode; | |
365 | inode->i_private = data; | |
366 | ||
367 | inode->i_fop = proxy_fops; | |
7d39bc50 NS |
368 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
369 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
370 | |
371 | d_instantiate(dentry, inode); | |
372 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
373 | return end_creating(dentry); | |
374 | } | |
375 | ||
1da177e4 LT |
376 | /** |
377 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 378 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 379 | * @mode: the permission that the file should have. |
1da177e4 | 380 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 381 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
382 | * file will be created in the root of the debugfs filesystem. |
383 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 384 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
385 | * the open() call. |
386 | * @fops: a pointer to a struct file_operations that should be used for | |
387 | * this file. | |
388 | * | |
389 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
390 | * wide range of flexibility in creating a file, or a directory (if you want |
391 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
392 | * recommended to be used instead.) |
393 | * | |
394 | * This function will return a pointer to a dentry if it succeeds. This | |
395 | * pointer must be passed to the debugfs_remove() function when the file is | |
396 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 397 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 398 | * |
6468b3af | 399 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 400 | * returned. |
1da177e4 | 401 | */ |
f4ae40a6 | 402 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 403 | struct dentry *parent, void *data, |
99ac48f5 | 404 | const struct file_operations *fops) |
1da177e4 | 405 | { |
680b3024 | 406 | |
49d200de NS |
407 | return __debugfs_create_file(name, mode, parent, data, |
408 | fops ? &debugfs_full_proxy_file_operations : | |
409 | &debugfs_noop_file_operations, | |
410 | fops); | |
411 | } | |
412 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 413 | |
c6468808 NS |
414 | /** |
415 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
416 | * @name: a pointer to a string containing the name of the file to create. | |
417 | * @mode: the permission that the file should have. | |
418 | * @parent: a pointer to the parent dentry for this file. This should be a | |
419 | * directory dentry if set. If this parameter is NULL, then the | |
420 | * file will be created in the root of the debugfs filesystem. | |
421 | * @data: a pointer to something that the caller will want to get to later | |
422 | * on. The inode.i_private pointer will point to this value on | |
423 | * the open() call. | |
424 | * @fops: a pointer to a struct file_operations that should be used for | |
425 | * this file. | |
426 | * | |
427 | * debugfs_create_file_unsafe() is completely analogous to | |
428 | * debugfs_create_file(), the only difference being that the fops | |
429 | * handed it will not get protected against file removals by the | |
430 | * debugfs core. | |
431 | * | |
432 | * It is your responsibility to protect your struct file_operation | |
433 | * methods against file removals by means of debugfs_use_file_start() | |
434 | * and debugfs_use_file_finish(). ->open() is still protected by | |
435 | * debugfs though. | |
436 | * | |
437 | * Any struct file_operations defined by means of | |
438 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
439 | * thus, may be used here. | |
440 | */ | |
49d200de NS |
441 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
442 | struct dentry *parent, void *data, | |
443 | const struct file_operations *fops) | |
444 | { | |
9fd4dcec | 445 | |
49d200de NS |
446 | return __debugfs_create_file(name, mode, parent, data, |
447 | fops ? &debugfs_open_proxy_file_operations : | |
448 | &debugfs_noop_file_operations, | |
449 | fops); | |
1da177e4 | 450 | } |
c6468808 | 451 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 452 | |
e59b4e91 DH |
453 | /** |
454 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
455 | * @name: a pointer to a string containing the name of the file to create. | |
456 | * @mode: the permission that the file should have. | |
457 | * @parent: a pointer to the parent dentry for this file. This should be a | |
458 | * directory dentry if set. If this parameter is NULL, then the | |
459 | * file will be created in the root of the debugfs filesystem. | |
460 | * @data: a pointer to something that the caller will want to get to later | |
461 | * on. The inode.i_private pointer will point to this value on | |
462 | * the open() call. | |
463 | * @fops: a pointer to a struct file_operations that should be used for | |
464 | * this file. | |
465 | * @file_size: initial file size | |
466 | * | |
467 | * This is the basic "create a file" function for debugfs. It allows for a | |
468 | * wide range of flexibility in creating a file, or a directory (if you want | |
469 | * to create a directory, the debugfs_create_dir() function is | |
470 | * recommended to be used instead.) | |
471 | * | |
472 | * This function will return a pointer to a dentry if it succeeds. This | |
473 | * pointer must be passed to the debugfs_remove() function when the file is | |
474 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
475 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
476 | * | |
477 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
478 | * returned. | |
479 | */ | |
480 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
481 | struct dentry *parent, void *data, | |
482 | const struct file_operations *fops, | |
483 | loff_t file_size) | |
484 | { | |
485 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
486 | ||
487 | if (de) | |
2b0143b5 | 488 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
489 | return de; |
490 | } | |
491 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
492 | ||
1da177e4 LT |
493 | /** |
494 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
495 | * @name: a pointer to a string containing the name of the directory to |
496 | * create. | |
497 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 498 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
499 | * directory will be created in the root of the debugfs filesystem. |
500 | * | |
501 | * This function creates a directory in debugfs with the given name. | |
502 | * | |
503 | * This function will return a pointer to a dentry if it succeeds. This | |
504 | * pointer must be passed to the debugfs_remove() function when the file is | |
505 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 506 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 507 | * |
6468b3af | 508 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 509 | * returned. |
1da177e4 LT |
510 | */ |
511 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
512 | { | |
ad5abd5b | 513 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 514 | struct inode *inode; |
ad5abd5b AV |
515 | |
516 | if (IS_ERR(dentry)) | |
517 | return NULL; | |
518 | ||
edac65ea | 519 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 520 | if (unlikely(!inode)) |
5233e311 | 521 | return failed_creating(dentry); |
680b3024 | 522 | |
edac65ea AV |
523 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
524 | inode->i_op = &simple_dir_inode_operations; | |
525 | inode->i_fop = &simple_dir_operations; | |
526 | ||
527 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
528 | inc_nlink(inode); | |
680b3024 | 529 | d_instantiate(dentry, inode); |
2b0143b5 DH |
530 | inc_nlink(d_inode(dentry->d_parent)); |
531 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 532 | return end_creating(dentry); |
1da177e4 LT |
533 | } |
534 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
535 | ||
77b3da6e AV |
536 | /** |
537 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
538 | * @name: a pointer to a string containing the name of the file to create. | |
539 | * @parent: a pointer to the parent dentry for this file. This should be a | |
540 | * directory dentry if set. If this parameter is NULL, then the | |
541 | * file will be created in the root of the debugfs filesystem. | |
542 | * @f: function to be called when pathname resolution steps on that one. | |
543 | * @data: opaque argument to pass to f(). | |
544 | * | |
545 | * @f should return what ->d_automount() would. | |
546 | */ | |
547 | struct dentry *debugfs_create_automount(const char *name, | |
548 | struct dentry *parent, | |
93faccbb | 549 | debugfs_automount_t f, |
77b3da6e AV |
550 | void *data) |
551 | { | |
552 | struct dentry *dentry = start_creating(name, parent); | |
553 | struct inode *inode; | |
554 | ||
555 | if (IS_ERR(dentry)) | |
556 | return NULL; | |
557 | ||
558 | inode = debugfs_get_inode(dentry->d_sb); | |
559 | if (unlikely(!inode)) | |
560 | return failed_creating(dentry); | |
561 | ||
87243deb | 562 | make_empty_dir_inode(inode); |
77b3da6e AV |
563 | inode->i_flags |= S_AUTOMOUNT; |
564 | inode->i_private = data; | |
565 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
566 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
567 | inc_nlink(inode); | |
77b3da6e | 568 | d_instantiate(dentry, inode); |
a8f324a4 RP |
569 | inc_nlink(d_inode(dentry->d_parent)); |
570 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
571 | return end_creating(dentry); |
572 | } | |
573 | EXPORT_SYMBOL(debugfs_create_automount); | |
574 | ||
66f54963 PO |
575 | /** |
576 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
577 | * @name: a pointer to a string containing the name of the symbolic link to | |
578 | * create. | |
579 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 580 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
581 | * then the symbolic link will be created in the root of the debugfs |
582 | * filesystem. | |
583 | * @target: a pointer to a string containing the path to the target of the | |
584 | * symbolic link. | |
585 | * | |
586 | * This function creates a symbolic link with the given name in debugfs that | |
587 | * links to the given target path. | |
588 | * | |
589 | * This function will return a pointer to a dentry if it succeeds. This | |
590 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
591 | * link is to be removed (no automatic cleanup happens if your module is | |
592 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
593 | * returned. | |
594 | * | |
595 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 596 | * returned. |
66f54963 PO |
597 | */ |
598 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
599 | const char *target) | |
600 | { | |
ad5abd5b | 601 | struct dentry *dentry; |
680b3024 AV |
602 | struct inode *inode; |
603 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 PO |
604 | if (!link) |
605 | return NULL; | |
606 | ||
ad5abd5b | 607 | dentry = start_creating(name, parent); |
ad5abd5b | 608 | if (IS_ERR(dentry)) { |
66f54963 | 609 | kfree(link); |
ad5abd5b AV |
610 | return NULL; |
611 | } | |
612 | ||
edac65ea | 613 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 614 | if (unlikely(!inode)) { |
ad5abd5b | 615 | kfree(link); |
5233e311 | 616 | return failed_creating(dentry); |
680b3024 | 617 | } |
edac65ea | 618 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5723cb01 AV |
619 | inode->i_op = &simple_symlink_inode_operations; |
620 | inode->i_link = link; | |
680b3024 | 621 | d_instantiate(dentry, inode); |
5233e311 | 622 | return end_creating(dentry); |
66f54963 PO |
623 | } |
624 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
625 | ||
e9117a5a NS |
626 | static void __debugfs_remove_file(struct dentry *dentry, struct dentry *parent) |
627 | { | |
628 | struct debugfs_fsdata *fsd; | |
629 | ||
630 | simple_unlink(d_inode(parent), dentry); | |
631 | d_delete(dentry); | |
7d39bc50 NS |
632 | |
633 | /* | |
634 | * Paired with the closing smp_mb() implied by a successful | |
635 | * cmpxchg() in debugfs_file_get(): either | |
636 | * debugfs_file_get() must see a dead dentry or we must see a | |
637 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
638 | */ | |
639 | smp_mb(); | |
640 | fsd = READ_ONCE(dentry->d_fsdata); | |
641 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
642 | return; | |
e9117a5a NS |
643 | if (!refcount_dec_and_test(&fsd->active_users)) |
644 | wait_for_completion(&fsd->active_users_drained); | |
645 | } | |
646 | ||
25d41d84 | 647 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
648 | { |
649 | int ret = 0; | |
650 | ||
dc3f4198 | 651 | if (simple_positive(dentry)) { |
0db59e59 | 652 | dget(dentry); |
e9117a5a NS |
653 | if (!d_is_reg(dentry)) { |
654 | if (d_is_dir(dentry)) | |
655 | ret = simple_rmdir(d_inode(parent), dentry); | |
656 | else | |
657 | simple_unlink(d_inode(parent), dentry); | |
658 | if (!ret) | |
659 | d_delete(dentry); | |
660 | } else { | |
661 | __debugfs_remove_file(dentry, parent); | |
662 | } | |
0db59e59 | 663 | dput(dentry); |
9505e637 | 664 | } |
25d41d84 | 665 | return ret; |
9505e637 HS |
666 | } |
667 | ||
1da177e4 LT |
668 | /** |
669 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 | 670 | * @dentry: a pointer to a the dentry of the file or directory to be |
398dc4ad UM |
671 | * removed. If this parameter is NULL or an error value, nothing |
672 | * will be done. | |
1da177e4 LT |
673 | * |
674 | * This function removes a file or directory in debugfs that was previously | |
675 | * created with a call to another debugfs function (like | |
5a65980e | 676 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
677 | * |
678 | * This function is required to be called in order for the file to be | |
679 | * removed, no automatic cleanup of files will happen when a module is | |
680 | * removed, you are responsible here. | |
681 | */ | |
682 | void debugfs_remove(struct dentry *dentry) | |
683 | { | |
684 | struct dentry *parent; | |
25d41d84 JK |
685 | int ret; |
686 | ||
a59d6293 | 687 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
688 | return; |
689 | ||
690 | parent = dentry->d_parent; | |
5955102c | 691 | inode_lock(d_inode(parent)); |
25d41d84 | 692 | ret = __debugfs_remove(dentry, parent); |
5955102c | 693 | inode_unlock(d_inode(parent)); |
25d41d84 JK |
694 | if (!ret) |
695 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
696 | } |
697 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
698 | ||
699 | /** | |
700 | * debugfs_remove_recursive - recursively removes a directory | |
398dc4ad UM |
701 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
702 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
703 | * |
704 | * This function recursively removes a directory tree in debugfs that | |
705 | * was previously created with a call to another debugfs function | |
706 | * (like debugfs_create_file() or variants thereof.) | |
707 | * | |
708 | * This function is required to be called in order for the file to be | |
709 | * removed, no automatic cleanup of files will happen when a module is | |
710 | * removed, you are responsible here. | |
711 | */ | |
712 | void debugfs_remove_recursive(struct dentry *dentry) | |
713 | { | |
485d4402 | 714 | struct dentry *child, *parent; |
9505e637 | 715 | |
a59d6293 | 716 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
717 | return; |
718 | ||
9505e637 | 719 | parent = dentry; |
776164c1 | 720 | down: |
5955102c | 721 | inode_lock(d_inode(parent)); |
485d4402 SR |
722 | loop: |
723 | /* | |
724 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
725 | * lock, the child can be unlinked and set to be freed which can | |
726 | * use the d_u.d_child as the rcu head and corrupt this list. | |
727 | */ | |
728 | spin_lock(&parent->d_lock); | |
946e51f2 | 729 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 730 | if (!simple_positive(child)) |
776164c1 | 731 | continue; |
9505e637 | 732 | |
776164c1 | 733 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 734 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 735 | spin_unlock(&parent->d_lock); |
5955102c | 736 | inode_unlock(d_inode(parent)); |
9505e637 | 737 | parent = child; |
776164c1 | 738 | goto down; |
1da177e4 | 739 | } |
485d4402 SR |
740 | |
741 | spin_unlock(&parent->d_lock); | |
742 | ||
776164c1 ON |
743 | if (!__debugfs_remove(child, parent)) |
744 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
745 | |
746 | /* | |
747 | * The parent->d_lock protects agaist child from unlinking | |
748 | * from d_subdirs. When releasing the parent->d_lock we can | |
749 | * no longer trust that the next pointer is valid. | |
750 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 751 | * simple_positive() check. |
485d4402 SR |
752 | */ |
753 | goto loop; | |
1da177e4 | 754 | } |
485d4402 | 755 | spin_unlock(&parent->d_lock); |
9505e637 | 756 | |
5955102c | 757 | inode_unlock(d_inode(parent)); |
776164c1 ON |
758 | child = parent; |
759 | parent = parent->d_parent; | |
5955102c | 760 | inode_lock(d_inode(parent)); |
776164c1 | 761 | |
485d4402 SR |
762 | if (child != dentry) |
763 | /* go up */ | |
764 | goto loop; | |
776164c1 ON |
765 | |
766 | if (!__debugfs_remove(child, parent)) | |
767 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
5955102c | 768 | inode_unlock(d_inode(parent)); |
1da177e4 | 769 | } |
9505e637 | 770 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 771 | |
cfc94cdf JK |
772 | /** |
773 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
774 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
775 | * should be a directory dentry. | |
776 | * @old_dentry: dentry of an object to be renamed. | |
777 | * @new_dir: a pointer to the parent dentry where the object should be | |
778 | * moved. This should be a directory dentry. | |
779 | * @new_name: a pointer to a string containing the target name. | |
780 | * | |
781 | * This function renames a file/directory in debugfs. The target must not | |
782 | * exist for rename to succeed. | |
783 | * | |
784 | * This function will return a pointer to old_dentry (which is updated to | |
785 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
786 | * returned. | |
787 | * | |
788 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
789 | * returned. | |
790 | */ | |
791 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
792 | struct dentry *new_dir, const char *new_name) | |
793 | { | |
794 | int error; | |
795 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 796 | struct name_snapshot old_name; |
cfc94cdf | 797 | |
98839c58 GKH |
798 | if (IS_ERR(old_dir)) |
799 | return old_dir; | |
800 | if (IS_ERR(new_dir)) | |
801 | return new_dir; | |
802 | if (IS_ERR_OR_NULL(old_dentry)) | |
803 | return old_dentry; | |
804 | ||
cfc94cdf JK |
805 | trap = lock_rename(new_dir, old_dir); |
806 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 807 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
808 | goto exit; |
809 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 810 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
811 | d_mountpoint(old_dentry)) |
812 | goto exit; | |
813 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
814 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 815 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
816 | goto exit; |
817 | ||
49d31c2f | 818 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 819 | |
2b0143b5 | 820 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
e0e0be8a | 821 | dentry, 0); |
cfc94cdf | 822 | if (error) { |
49d31c2f | 823 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
824 | goto exit; |
825 | } | |
826 | d_move(old_dentry, dentry); | |
49d31c2f | 827 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name, |
e36cb0b8 | 828 | d_is_dir(old_dentry), |
5a190ae6 | 829 | NULL, old_dentry); |
49d31c2f | 830 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
831 | unlock_rename(new_dir, old_dir); |
832 | dput(dentry); | |
833 | return old_dentry; | |
834 | exit: | |
835 | if (dentry && !IS_ERR(dentry)) | |
836 | dput(dentry); | |
837 | unlock_rename(new_dir, old_dir); | |
838 | return NULL; | |
839 | } | |
840 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
841 | ||
c0f92ba9 FW |
842 | /** |
843 | * debugfs_initialized - Tells whether debugfs has been registered | |
844 | */ | |
845 | bool debugfs_initialized(void) | |
846 | { | |
847 | return debugfs_registered; | |
848 | } | |
849 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
850 | ||
1da177e4 LT |
851 | static int __init debugfs_init(void) |
852 | { | |
853 | int retval; | |
854 | ||
f9bb4882 EB |
855 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
856 | if (retval) | |
857 | return retval; | |
1da177e4 LT |
858 | |
859 | retval = register_filesystem(&debug_fs_type); | |
860 | if (retval) | |
f9bb4882 | 861 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
862 | else |
863 | debugfs_registered = true; | |
864 | ||
1da177e4 LT |
865 | return retval; |
866 | } | |
1da177e4 | 867 | core_initcall(debugfs_init); |
1da177e4 | 868 |