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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 | ||
0db59e59 AV |
166 | static void debugfs_evict_inode(struct inode *inode) |
167 | { | |
168 | truncate_inode_pages_final(&inode->i_data); | |
169 | clear_inode(inode); | |
170 | if (S_ISLNK(inode->i_mode)) | |
5723cb01 | 171 | kfree(inode->i_link); |
0db59e59 AV |
172 | } |
173 | ||
d6e48686 LN |
174 | static const struct super_operations debugfs_super_operations = { |
175 | .statfs = simple_statfs, | |
176 | .remount_fs = debugfs_remount, | |
177 | .show_options = debugfs_show_options, | |
0db59e59 | 178 | .evict_inode = debugfs_evict_inode, |
d6e48686 LN |
179 | }; |
180 | ||
7c8d4698 NS |
181 | static void debugfs_release_dentry(struct dentry *dentry) |
182 | { | |
7d39bc50 NS |
183 | void *fsd = dentry->d_fsdata; |
184 | ||
185 | if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) | |
186 | kfree(dentry->d_fsdata); | |
7c8d4698 NS |
187 | } |
188 | ||
77b3da6e AV |
189 | static struct vfsmount *debugfs_automount(struct path *path) |
190 | { | |
93faccbb EB |
191 | debugfs_automount_t f; |
192 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
193 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
194 | } |
195 | ||
196 | static const struct dentry_operations debugfs_dops = { | |
197 | .d_delete = always_delete_dentry, | |
7c8d4698 | 198 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
199 | .d_automount = debugfs_automount, |
200 | }; | |
201 | ||
1da177e4 LT |
202 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
203 | { | |
cda37124 | 204 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
205 | struct debugfs_fs_info *fsi; |
206 | int err; | |
207 | ||
d6e48686 LN |
208 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
209 | sb->s_fs_info = fsi; | |
210 | if (!fsi) { | |
211 | err = -ENOMEM; | |
212 | goto fail; | |
213 | } | |
214 | ||
215 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
216 | if (err) | |
217 | goto fail; | |
218 | ||
219 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
220 | if (err) | |
221 | goto fail; | |
222 | ||
223 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 224 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
225 | |
226 | debugfs_apply_options(sb); | |
227 | ||
228 | return 0; | |
1da177e4 | 229 | |
d6e48686 LN |
230 | fail: |
231 | kfree(fsi); | |
232 | sb->s_fs_info = NULL; | |
233 | return err; | |
1da177e4 LT |
234 | } |
235 | ||
fc14f2fe | 236 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 237 | int flags, const char *dev_name, |
fc14f2fe | 238 | void *data) |
1da177e4 | 239 | { |
fc14f2fe | 240 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
241 | } |
242 | ||
243 | static struct file_system_type debug_fs_type = { | |
244 | .owner = THIS_MODULE, | |
245 | .name = "debugfs", | |
fc14f2fe | 246 | .mount = debug_mount, |
1da177e4 LT |
247 | .kill_sb = kill_litter_super, |
248 | }; | |
7f78e035 | 249 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 250 | |
a7c5437b OS |
251 | /** |
252 | * debugfs_lookup() - look up an existing debugfs file | |
253 | * @name: a pointer to a string containing the name of the file to look up. | |
254 | * @parent: a pointer to the parent dentry of the file. | |
255 | * | |
256 | * This function will return a pointer to a dentry if it succeeds. If the file | |
257 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
258 | * dentry must be passed to dput() when it is no longer needed. | |
259 | * | |
260 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
261 | * returned. | |
262 | */ | |
263 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
264 | { | |
265 | struct dentry *dentry; | |
266 | ||
267 | if (IS_ERR(parent)) | |
268 | return NULL; | |
269 | ||
270 | if (!parent) | |
271 | parent = debugfs_mount->mnt_root; | |
272 | ||
cd1c0c93 | 273 | dentry = lookup_one_len_unlocked(name, parent, strlen(name)); |
a7c5437b OS |
274 | if (IS_ERR(dentry)) |
275 | return NULL; | |
276 | if (!d_really_is_positive(dentry)) { | |
277 | dput(dentry); | |
278 | return NULL; | |
279 | } | |
280 | return dentry; | |
281 | } | |
282 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
283 | ||
190afd81 | 284 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 285 | { |
190afd81 | 286 | struct dentry *dentry; |
cfa57c11 AV |
287 | int error; |
288 | ||
289 | pr_debug("debugfs: creating file '%s'\n",name); | |
290 | ||
c9e15f25 GK |
291 | if (IS_ERR(parent)) |
292 | return parent; | |
293 | ||
cfa57c11 AV |
294 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
295 | &debugfs_mount_count); | |
296 | if (error) | |
190afd81 | 297 | return ERR_PTR(error); |
1da177e4 LT |
298 | |
299 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 300 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
301 | * block. A pointer to that is in the struct vfsmount that we |
302 | * have around. | |
303 | */ | |
ef52c75e | 304 | if (!parent) |
4c1d5a64 | 305 | parent = debugfs_mount->mnt_root; |
1da177e4 | 306 | |
5955102c | 307 | inode_lock(d_inode(parent)); |
cfa57c11 | 308 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 309 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
cfa57c11 | 310 | dput(dentry); |
190afd81 AV |
311 | dentry = ERR_PTR(-EEXIST); |
312 | } | |
0ee9608c DB |
313 | |
314 | if (IS_ERR(dentry)) { | |
5955102c | 315 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
316 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
317 | } | |
318 | ||
190afd81 AV |
319 | return dentry; |
320 | } | |
321 | ||
5233e311 | 322 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 323 | { |
5955102c | 324 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 325 | dput(dentry); |
5233e311 | 326 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
ff9fb72b | 327 | return ERR_PTR(-ENOMEM); |
5233e311 | 328 | } |
1da177e4 | 329 | |
5233e311 AV |
330 | static struct dentry *end_creating(struct dentry *dentry) |
331 | { | |
5955102c | 332 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
333 | return dentry; |
334 | } | |
335 | ||
49d200de NS |
336 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
337 | struct dentry *parent, void *data, | |
338 | const struct file_operations *proxy_fops, | |
339 | const struct file_operations *real_fops) | |
340 | { | |
341 | struct dentry *dentry; | |
342 | struct inode *inode; | |
343 | ||
344 | if (!(mode & S_IFMT)) | |
345 | mode |= S_IFREG; | |
346 | BUG_ON(!S_ISREG(mode)); | |
347 | dentry = start_creating(name, parent); | |
348 | ||
7d39bc50 | 349 | if (IS_ERR(dentry)) |
ff9fb72b | 350 | return dentry; |
49d200de NS |
351 | |
352 | inode = debugfs_get_inode(dentry->d_sb); | |
7d39bc50 | 353 | if (unlikely(!inode)) |
49d200de NS |
354 | return failed_creating(dentry); |
355 | ||
356 | inode->i_mode = mode; | |
357 | inode->i_private = data; | |
358 | ||
359 | inode->i_fop = proxy_fops; | |
7d39bc50 NS |
360 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
361 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
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, | |
ff9fb72b GKH |
389 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
390 | * returned. | |
1da177e4 | 391 | * |
6468b3af | 392 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 393 | * returned. |
1da177e4 | 394 | */ |
f4ae40a6 | 395 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 396 | struct dentry *parent, void *data, |
99ac48f5 | 397 | const struct file_operations *fops) |
1da177e4 | 398 | { |
680b3024 | 399 | |
49d200de NS |
400 | return __debugfs_create_file(name, mode, parent, data, |
401 | fops ? &debugfs_full_proxy_file_operations : | |
402 | &debugfs_noop_file_operations, | |
403 | fops); | |
404 | } | |
405 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 406 | |
c6468808 NS |
407 | /** |
408 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
409 | * @name: a pointer to a string containing the name of the file to create. | |
410 | * @mode: the permission that the file should have. | |
411 | * @parent: a pointer to the parent dentry for this file. This should be a | |
412 | * directory dentry if set. If this parameter is NULL, then the | |
413 | * file will be created in the root of the debugfs filesystem. | |
414 | * @data: a pointer to something that the caller will want to get to later | |
415 | * on. The inode.i_private pointer will point to this value on | |
416 | * the open() call. | |
417 | * @fops: a pointer to a struct file_operations that should be used for | |
418 | * this file. | |
419 | * | |
420 | * debugfs_create_file_unsafe() is completely analogous to | |
421 | * debugfs_create_file(), the only difference being that the fops | |
422 | * handed it will not get protected against file removals by the | |
423 | * debugfs core. | |
424 | * | |
425 | * It is your responsibility to protect your struct file_operation | |
0eeb2731 SS |
426 | * methods against file removals by means of debugfs_file_get() |
427 | * and debugfs_file_put(). ->open() is still protected by | |
c6468808 NS |
428 | * debugfs though. |
429 | * | |
430 | * Any struct file_operations defined by means of | |
431 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
432 | * thus, may be used here. | |
433 | */ | |
49d200de NS |
434 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
435 | struct dentry *parent, void *data, | |
436 | const struct file_operations *fops) | |
437 | { | |
9fd4dcec | 438 | |
49d200de NS |
439 | return __debugfs_create_file(name, mode, parent, data, |
440 | fops ? &debugfs_open_proxy_file_operations : | |
441 | &debugfs_noop_file_operations, | |
442 | fops); | |
1da177e4 | 443 | } |
c6468808 | 444 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 445 | |
e59b4e91 DH |
446 | /** |
447 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
448 | * @name: a pointer to a string containing the name of the file to create. | |
449 | * @mode: the permission that the file should have. | |
450 | * @parent: a pointer to the parent dentry for this file. This should be a | |
451 | * directory dentry if set. If this parameter is NULL, then the | |
452 | * file will be created in the root of the debugfs filesystem. | |
453 | * @data: a pointer to something that the caller will want to get to later | |
454 | * on. The inode.i_private pointer will point to this value on | |
455 | * the open() call. | |
456 | * @fops: a pointer to a struct file_operations that should be used for | |
457 | * this file. | |
458 | * @file_size: initial file size | |
459 | * | |
460 | * This is the basic "create a file" function for debugfs. It allows for a | |
461 | * wide range of flexibility in creating a file, or a directory (if you want | |
462 | * to create a directory, the debugfs_create_dir() function is | |
463 | * recommended to be used instead.) | |
464 | * | |
465 | * This function will return a pointer to a dentry if it succeeds. This | |
466 | * pointer must be passed to the debugfs_remove() function when the file is | |
467 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
ff9fb72b GKH |
468 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
469 | * returned. | |
e59b4e91 DH |
470 | * |
471 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
472 | * returned. | |
473 | */ | |
474 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
475 | struct dentry *parent, void *data, | |
476 | const struct file_operations *fops, | |
477 | loff_t file_size) | |
478 | { | |
479 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
480 | ||
481 | if (de) | |
2b0143b5 | 482 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
483 | return de; |
484 | } | |
485 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
486 | ||
1da177e4 LT |
487 | /** |
488 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
489 | * @name: a pointer to a string containing the name of the directory to |
490 | * create. | |
491 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 492 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
493 | * directory will be created in the root of the debugfs filesystem. |
494 | * | |
495 | * This function creates a directory in debugfs with the given name. | |
496 | * | |
497 | * This function will return a pointer to a dentry if it succeeds. This | |
498 | * pointer must be passed to the debugfs_remove() function when the file is | |
499 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
ff9fb72b GKH |
500 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
501 | * returned. | |
1da177e4 | 502 | * |
6468b3af | 503 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 504 | * returned. |
1da177e4 LT |
505 | */ |
506 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
507 | { | |
ad5abd5b | 508 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 509 | struct inode *inode; |
ad5abd5b AV |
510 | |
511 | if (IS_ERR(dentry)) | |
ff9fb72b | 512 | return dentry; |
ad5abd5b | 513 | |
edac65ea | 514 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 515 | if (unlikely(!inode)) |
5233e311 | 516 | return failed_creating(dentry); |
680b3024 | 517 | |
f5b7769e | 518 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
edac65ea AV |
519 | inode->i_op = &simple_dir_inode_operations; |
520 | inode->i_fop = &simple_dir_operations; | |
521 | ||
522 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
523 | inc_nlink(inode); | |
680b3024 | 524 | d_instantiate(dentry, inode); |
2b0143b5 DH |
525 | inc_nlink(d_inode(dentry->d_parent)); |
526 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 527 | return end_creating(dentry); |
1da177e4 LT |
528 | } |
529 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
530 | ||
77b3da6e AV |
531 | /** |
532 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
533 | * @name: a pointer to a string containing the name of the file to create. | |
534 | * @parent: a pointer to the parent dentry for this file. This should be a | |
535 | * directory dentry if set. If this parameter is NULL, then the | |
536 | * file will be created in the root of the debugfs filesystem. | |
537 | * @f: function to be called when pathname resolution steps on that one. | |
538 | * @data: opaque argument to pass to f(). | |
539 | * | |
540 | * @f should return what ->d_automount() would. | |
541 | */ | |
542 | struct dentry *debugfs_create_automount(const char *name, | |
543 | struct dentry *parent, | |
93faccbb | 544 | debugfs_automount_t f, |
77b3da6e AV |
545 | void *data) |
546 | { | |
547 | struct dentry *dentry = start_creating(name, parent); | |
548 | struct inode *inode; | |
549 | ||
550 | if (IS_ERR(dentry)) | |
ff9fb72b | 551 | return dentry; |
77b3da6e AV |
552 | |
553 | inode = debugfs_get_inode(dentry->d_sb); | |
554 | if (unlikely(!inode)) | |
555 | return failed_creating(dentry); | |
556 | ||
87243deb | 557 | make_empty_dir_inode(inode); |
77b3da6e AV |
558 | inode->i_flags |= S_AUTOMOUNT; |
559 | inode->i_private = data; | |
560 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
561 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
562 | inc_nlink(inode); | |
77b3da6e | 563 | d_instantiate(dentry, inode); |
a8f324a4 RP |
564 | inc_nlink(d_inode(dentry->d_parent)); |
565 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
566 | return end_creating(dentry); |
567 | } | |
568 | EXPORT_SYMBOL(debugfs_create_automount); | |
569 | ||
66f54963 PO |
570 | /** |
571 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
572 | * @name: a pointer to a string containing the name of the symbolic link to | |
573 | * create. | |
574 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 575 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
576 | * then the symbolic link will be created in the root of the debugfs |
577 | * filesystem. | |
578 | * @target: a pointer to a string containing the path to the target of the | |
579 | * symbolic link. | |
580 | * | |
581 | * This function creates a symbolic link with the given name in debugfs that | |
582 | * links to the given target path. | |
583 | * | |
584 | * This function will return a pointer to a dentry if it succeeds. This | |
585 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
586 | * link is to be removed (no automatic cleanup happens if your module is | |
ff9fb72b GKH |
587 | * unloaded, you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) |
588 | * will be returned. | |
66f54963 PO |
589 | * |
590 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 591 | * returned. |
66f54963 PO |
592 | */ |
593 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
594 | const char *target) | |
595 | { | |
ad5abd5b | 596 | struct dentry *dentry; |
680b3024 AV |
597 | struct inode *inode; |
598 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 | 599 | if (!link) |
ff9fb72b | 600 | return ERR_PTR(-ENOMEM); |
66f54963 | 601 | |
ad5abd5b | 602 | dentry = start_creating(name, parent); |
ad5abd5b | 603 | if (IS_ERR(dentry)) { |
66f54963 | 604 | kfree(link); |
ff9fb72b | 605 | return dentry; |
ad5abd5b AV |
606 | } |
607 | ||
edac65ea | 608 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 609 | if (unlikely(!inode)) { |
ad5abd5b | 610 | kfree(link); |
5233e311 | 611 | return failed_creating(dentry); |
680b3024 | 612 | } |
edac65ea | 613 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5723cb01 AV |
614 | inode->i_op = &simple_symlink_inode_operations; |
615 | inode->i_link = link; | |
680b3024 | 616 | d_instantiate(dentry, inode); |
5233e311 | 617 | return end_creating(dentry); |
66f54963 PO |
618 | } |
619 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
620 | ||
e9117a5a NS |
621 | static void __debugfs_remove_file(struct dentry *dentry, struct dentry *parent) |
622 | { | |
623 | struct debugfs_fsdata *fsd; | |
624 | ||
625 | simple_unlink(d_inode(parent), dentry); | |
626 | d_delete(dentry); | |
7d39bc50 NS |
627 | |
628 | /* | |
629 | * Paired with the closing smp_mb() implied by a successful | |
630 | * cmpxchg() in debugfs_file_get(): either | |
631 | * debugfs_file_get() must see a dead dentry or we must see a | |
632 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
633 | */ | |
634 | smp_mb(); | |
635 | fsd = READ_ONCE(dentry->d_fsdata); | |
636 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
637 | return; | |
e9117a5a NS |
638 | if (!refcount_dec_and_test(&fsd->active_users)) |
639 | wait_for_completion(&fsd->active_users_drained); | |
640 | } | |
641 | ||
25d41d84 | 642 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
643 | { |
644 | int ret = 0; | |
645 | ||
dc3f4198 | 646 | if (simple_positive(dentry)) { |
0db59e59 | 647 | dget(dentry); |
e9117a5a NS |
648 | if (!d_is_reg(dentry)) { |
649 | if (d_is_dir(dentry)) | |
650 | ret = simple_rmdir(d_inode(parent), dentry); | |
651 | else | |
652 | simple_unlink(d_inode(parent), dentry); | |
653 | if (!ret) | |
654 | d_delete(dentry); | |
655 | } else { | |
656 | __debugfs_remove_file(dentry, parent); | |
657 | } | |
0db59e59 | 658 | dput(dentry); |
9505e637 | 659 | } |
25d41d84 | 660 | return ret; |
9505e637 HS |
661 | } |
662 | ||
1da177e4 LT |
663 | /** |
664 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 | 665 | * @dentry: a pointer to a the dentry of the file or directory to be |
398dc4ad UM |
666 | * removed. If this parameter is NULL or an error value, nothing |
667 | * will be done. | |
1da177e4 LT |
668 | * |
669 | * This function removes a file or directory in debugfs that was previously | |
670 | * created with a call to another debugfs function (like | |
5a65980e | 671 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
672 | * |
673 | * This function is required to be called in order for the file to be | |
674 | * removed, no automatic cleanup of files will happen when a module is | |
675 | * removed, you are responsible here. | |
676 | */ | |
677 | void debugfs_remove(struct dentry *dentry) | |
678 | { | |
679 | struct dentry *parent; | |
25d41d84 JK |
680 | int ret; |
681 | ||
a59d6293 | 682 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
683 | return; |
684 | ||
685 | parent = dentry->d_parent; | |
5955102c | 686 | inode_lock(d_inode(parent)); |
25d41d84 | 687 | ret = __debugfs_remove(dentry, parent); |
5955102c | 688 | inode_unlock(d_inode(parent)); |
25d41d84 JK |
689 | if (!ret) |
690 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
691 | } |
692 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
693 | ||
694 | /** | |
695 | * debugfs_remove_recursive - recursively removes a directory | |
398dc4ad UM |
696 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
697 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
698 | * |
699 | * This function recursively removes a directory tree in debugfs that | |
700 | * was previously created with a call to another debugfs function | |
701 | * (like debugfs_create_file() or variants thereof.) | |
702 | * | |
703 | * This function is required to be called in order for the file to be | |
704 | * removed, no automatic cleanup of files will happen when a module is | |
705 | * removed, you are responsible here. | |
706 | */ | |
707 | void debugfs_remove_recursive(struct dentry *dentry) | |
708 | { | |
485d4402 | 709 | struct dentry *child, *parent; |
9505e637 | 710 | |
a59d6293 | 711 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
712 | return; |
713 | ||
9505e637 | 714 | parent = dentry; |
776164c1 | 715 | down: |
5955102c | 716 | inode_lock(d_inode(parent)); |
485d4402 SR |
717 | loop: |
718 | /* | |
719 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
720 | * lock, the child can be unlinked and set to be freed which can | |
721 | * use the d_u.d_child as the rcu head and corrupt this list. | |
722 | */ | |
723 | spin_lock(&parent->d_lock); | |
946e51f2 | 724 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 725 | if (!simple_positive(child)) |
776164c1 | 726 | continue; |
9505e637 | 727 | |
776164c1 | 728 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 729 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 730 | spin_unlock(&parent->d_lock); |
5955102c | 731 | inode_unlock(d_inode(parent)); |
9505e637 | 732 | parent = child; |
776164c1 | 733 | goto down; |
1da177e4 | 734 | } |
485d4402 SR |
735 | |
736 | spin_unlock(&parent->d_lock); | |
737 | ||
776164c1 ON |
738 | if (!__debugfs_remove(child, parent)) |
739 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
740 | |
741 | /* | |
742 | * The parent->d_lock protects agaist child from unlinking | |
743 | * from d_subdirs. When releasing the parent->d_lock we can | |
744 | * no longer trust that the next pointer is valid. | |
745 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 746 | * simple_positive() check. |
485d4402 SR |
747 | */ |
748 | goto loop; | |
1da177e4 | 749 | } |
485d4402 | 750 | spin_unlock(&parent->d_lock); |
9505e637 | 751 | |
5955102c | 752 | inode_unlock(d_inode(parent)); |
776164c1 ON |
753 | child = parent; |
754 | parent = parent->d_parent; | |
5955102c | 755 | inode_lock(d_inode(parent)); |
776164c1 | 756 | |
485d4402 SR |
757 | if (child != dentry) |
758 | /* go up */ | |
759 | goto loop; | |
776164c1 ON |
760 | |
761 | if (!__debugfs_remove(child, parent)) | |
762 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
5955102c | 763 | inode_unlock(d_inode(parent)); |
1da177e4 | 764 | } |
9505e637 | 765 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 766 | |
cfc94cdf JK |
767 | /** |
768 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
769 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
770 | * should be a directory dentry. | |
771 | * @old_dentry: dentry of an object to be renamed. | |
772 | * @new_dir: a pointer to the parent dentry where the object should be | |
773 | * moved. This should be a directory dentry. | |
774 | * @new_name: a pointer to a string containing the target name. | |
775 | * | |
776 | * This function renames a file/directory in debugfs. The target must not | |
777 | * exist for rename to succeed. | |
778 | * | |
779 | * This function will return a pointer to old_dentry (which is updated to | |
780 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
781 | * returned. | |
782 | * | |
783 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
784 | * returned. | |
785 | */ | |
786 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
787 | struct dentry *new_dir, const char *new_name) | |
788 | { | |
789 | int error; | |
790 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 791 | struct name_snapshot old_name; |
cfc94cdf | 792 | |
d88c93f0 GKH |
793 | if (IS_ERR(old_dir)) |
794 | return old_dir; | |
795 | if (IS_ERR(new_dir)) | |
796 | return new_dir; | |
797 | if (IS_ERR_OR_NULL(old_dentry)) | |
798 | return old_dentry; | |
799 | ||
cfc94cdf JK |
800 | trap = lock_rename(new_dir, old_dir); |
801 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 802 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
803 | goto exit; |
804 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 805 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
806 | d_mountpoint(old_dentry)) |
807 | goto exit; | |
808 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
809 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 810 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
811 | goto exit; |
812 | ||
49d31c2f | 813 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 814 | |
2b0143b5 | 815 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
e0e0be8a | 816 | dentry, 0); |
cfc94cdf | 817 | if (error) { |
49d31c2f | 818 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
819 | goto exit; |
820 | } | |
821 | d_move(old_dentry, dentry); | |
49d31c2f | 822 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name.name, |
e36cb0b8 | 823 | d_is_dir(old_dentry), |
5a190ae6 | 824 | NULL, old_dentry); |
49d31c2f | 825 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
826 | unlock_rename(new_dir, old_dir); |
827 | dput(dentry); | |
828 | return old_dentry; | |
829 | exit: | |
830 | if (dentry && !IS_ERR(dentry)) | |
831 | dput(dentry); | |
832 | unlock_rename(new_dir, old_dir); | |
ff9fb72b GKH |
833 | if (IS_ERR(dentry)) |
834 | return dentry; | |
835 | return ERR_PTR(-EINVAL); | |
cfc94cdf JK |
836 | } |
837 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
838 | ||
c0f92ba9 FW |
839 | /** |
840 | * debugfs_initialized - Tells whether debugfs has been registered | |
841 | */ | |
842 | bool debugfs_initialized(void) | |
843 | { | |
844 | return debugfs_registered; | |
845 | } | |
846 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
847 | ||
1da177e4 LT |
848 | static int __init debugfs_init(void) |
849 | { | |
850 | int retval; | |
851 | ||
f9bb4882 EB |
852 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
853 | if (retval) | |
854 | return retval; | |
1da177e4 LT |
855 | |
856 | retval = register_filesystem(&debug_fs_type); | |
857 | if (retval) | |
f9bb4882 | 858 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
859 | else |
860 | debugfs_registered = true; | |
861 | ||
1da177e4 LT |
862 | return retval; |
863 | } | |
1da177e4 | 864 | core_initcall(debugfs_init); |
1da177e4 | 865 |