]>
Commit | Line | Data |
---|---|---|
3bce94fd | 1 | // SPDX-License-Identifier: GPL-2.0 |
1da177e4 | 2 | /* |
bd33d12f | 3 | * inode.c - part of debugfs, a tiny little debug file system |
1da177e4 | 4 | * |
43e23b6c | 5 | * Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com> |
1da177e4 | 6 | * Copyright (C) 2004 IBM Inc. |
43e23b6c | 7 | * Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org> |
1da177e4 | 8 | * |
1da177e4 | 9 | * debugfs is for people to use instead of /proc or /sys. |
e1511a84 | 10 | * See ./Documentation/core-api/kernel-api.rst for more details. |
1da177e4 LT |
11 | */ |
12 | ||
d03ae477 GKH |
13 | #define pr_fmt(fmt) "debugfs: " fmt |
14 | ||
1da177e4 LT |
15 | #include <linux/module.h> |
16 | #include <linux/fs.h> | |
17 | #include <linux/mount.h> | |
18 | #include <linux/pagemap.h> | |
19 | #include <linux/init.h> | |
4d8ebddc | 20 | #include <linux/kobject.h> |
1da177e4 LT |
21 | #include <linux/namei.h> |
22 | #include <linux/debugfs.h> | |
4f36557f | 23 | #include <linux/fsnotify.h> |
66f54963 | 24 | #include <linux/string.h> |
d6e48686 LN |
25 | #include <linux/seq_file.h> |
26 | #include <linux/parser.h> | |
92562927 | 27 | #include <linux/magic.h> |
5a0e3ad6 | 28 | #include <linux/slab.h> |
5496197f | 29 | #include <linux/security.h> |
9fd4dcec NS |
30 | |
31 | #include "internal.h" | |
1da177e4 | 32 | |
82aceae4 | 33 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 34 | |
1da177e4 LT |
35 | static struct vfsmount *debugfs_mount; |
36 | static int debugfs_mount_count; | |
c0f92ba9 | 37 | static bool debugfs_registered; |
312723a0 | 38 | static unsigned int debugfs_allow __ro_after_init = DEFAULT_DEBUGFS_ALLOW_BITS; |
1da177e4 | 39 | |
5496197f DH |
40 | /* |
41 | * Don't allow access attributes to be changed whilst the kernel is locked down | |
42 | * so that we can use the file mode as part of a heuristic to determine whether | |
43 | * to lock down individual files. | |
44 | */ | |
c1632a0f | 45 | static int debugfs_setattr(struct mnt_idmap *idmap, |
549c7297 | 46 | struct dentry *dentry, struct iattr *ia) |
5496197f | 47 | { |
5881fa8d | 48 | int ret; |
5496197f | 49 | |
5881fa8d OM |
50 | if (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)) { |
51 | ret = security_locked_down(LOCKDOWN_DEBUGFS); | |
52 | if (ret) | |
53 | return ret; | |
54 | } | |
c1632a0f | 55 | return simple_setattr(&nop_mnt_idmap, dentry, ia); |
5496197f DH |
56 | } |
57 | ||
58 | static const struct inode_operations debugfs_file_inode_operations = { | |
59 | .setattr = debugfs_setattr, | |
60 | }; | |
61 | static const struct inode_operations debugfs_dir_inode_operations = { | |
62 | .lookup = simple_lookup, | |
63 | .setattr = debugfs_setattr, | |
64 | }; | |
65 | static const struct inode_operations debugfs_symlink_inode_operations = { | |
66 | .get_link = simple_get_link, | |
67 | .setattr = debugfs_setattr, | |
68 | }; | |
69 | ||
edac65ea | 70 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
71 | { |
72 | struct inode *inode = new_inode(sb); | |
1da177e4 | 73 | if (inode) { |
85fe4025 | 74 | inode->i_ino = get_next_ino(); |
d21b3c32 | 75 | simple_inode_init_ts(inode); |
1da177e4 | 76 | } |
88e412ea | 77 | return inode; |
1da177e4 LT |
78 | } |
79 | ||
d6e48686 | 80 | struct debugfs_mount_opts { |
7dc05881 EB |
81 | kuid_t uid; |
82 | kgid_t gid; | |
d6e48686 | 83 | umode_t mode; |
b8de524c BN |
84 | /* Opt_* bitfield. */ |
85 | unsigned int opts; | |
d6e48686 LN |
86 | }; |
87 | ||
88 | enum { | |
89 | Opt_uid, | |
90 | Opt_gid, | |
91 | Opt_mode, | |
92 | Opt_err | |
93 | }; | |
94 | ||
95 | static const match_table_t tokens = { | |
96 | {Opt_uid, "uid=%u"}, | |
97 | {Opt_gid, "gid=%u"}, | |
98 | {Opt_mode, "mode=%o"}, | |
99 | {Opt_err, NULL} | |
100 | }; | |
101 | ||
102 | struct debugfs_fs_info { | |
103 | struct debugfs_mount_opts mount_opts; | |
104 | }; | |
105 | ||
106 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
107 | { | |
108 | substring_t args[MAX_OPT_ARGS]; | |
109 | int option; | |
110 | int token; | |
7dc05881 EB |
111 | kuid_t uid; |
112 | kgid_t gid; | |
d6e48686 LN |
113 | char *p; |
114 | ||
b8de524c | 115 | opts->opts = 0; |
d6e48686 LN |
116 | opts->mode = DEBUGFS_DEFAULT_MODE; |
117 | ||
118 | while ((p = strsep(&data, ",")) != NULL) { | |
119 | if (!*p) | |
120 | continue; | |
121 | ||
122 | token = match_token(p, tokens, args); | |
123 | switch (token) { | |
124 | case Opt_uid: | |
125 | if (match_int(&args[0], &option)) | |
126 | return -EINVAL; | |
7dc05881 EB |
127 | uid = make_kuid(current_user_ns(), option); |
128 | if (!uid_valid(uid)) | |
129 | return -EINVAL; | |
130 | opts->uid = uid; | |
d6e48686 LN |
131 | break; |
132 | case Opt_gid: | |
f1688e04 | 133 | if (match_int(&args[0], &option)) |
d6e48686 | 134 | return -EINVAL; |
7dc05881 EB |
135 | gid = make_kgid(current_user_ns(), option); |
136 | if (!gid_valid(gid)) | |
137 | return -EINVAL; | |
138 | opts->gid = gid; | |
d6e48686 LN |
139 | break; |
140 | case Opt_mode: | |
141 | if (match_octal(&args[0], &option)) | |
142 | return -EINVAL; | |
143 | opts->mode = option & S_IALLUGO; | |
144 | break; | |
145 | /* | |
146 | * We might like to report bad mount options here; | |
147 | * but traditionally debugfs has ignored all mount options | |
148 | */ | |
149 | } | |
b8de524c BN |
150 | |
151 | opts->opts |= BIT(token); | |
d6e48686 LN |
152 | } |
153 | ||
154 | return 0; | |
155 | } | |
156 | ||
b8de524c | 157 | static void _debugfs_apply_options(struct super_block *sb, bool remount) |
d6e48686 LN |
158 | { |
159 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 160 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
161 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
162 | ||
b8de524c BN |
163 | /* |
164 | * On remount, only reset mode/uid/gid if they were provided as mount | |
165 | * options. | |
166 | */ | |
d6e48686 | 167 | |
b8de524c BN |
168 | if (!remount || opts->opts & BIT(Opt_mode)) { |
169 | inode->i_mode &= ~S_IALLUGO; | |
170 | inode->i_mode |= opts->mode; | |
171 | } | |
d6e48686 | 172 | |
b8de524c BN |
173 | if (!remount || opts->opts & BIT(Opt_uid)) |
174 | inode->i_uid = opts->uid; | |
175 | ||
176 | if (!remount || opts->opts & BIT(Opt_gid)) | |
177 | inode->i_gid = opts->gid; | |
178 | } | |
179 | ||
180 | static void debugfs_apply_options(struct super_block *sb) | |
181 | { | |
182 | _debugfs_apply_options(sb, false); | |
183 | } | |
184 | ||
185 | static void debugfs_apply_options_remount(struct super_block *sb) | |
186 | { | |
187 | _debugfs_apply_options(sb, true); | |
d6e48686 LN |
188 | } |
189 | ||
190 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
191 | { | |
192 | int err; | |
193 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
194 | ||
02b9984d | 195 | sync_filesystem(sb); |
d6e48686 LN |
196 | err = debugfs_parse_options(data, &fsi->mount_opts); |
197 | if (err) | |
198 | goto fail; | |
199 | ||
b8de524c | 200 | debugfs_apply_options_remount(sb); |
d6e48686 LN |
201 | |
202 | fail: | |
203 | return err; | |
204 | } | |
205 | ||
206 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
207 | { | |
208 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
209 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
210 | ||
7dc05881 EB |
211 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
212 | seq_printf(m, ",uid=%u", | |
213 | from_kuid_munged(&init_user_ns, opts->uid)); | |
214 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
215 | seq_printf(m, ",gid=%u", | |
216 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
217 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
218 | seq_printf(m, ",mode=%o", opts->mode); | |
219 | ||
220 | return 0; | |
221 | } | |
222 | ||
6234ddf4 | 223 | static void debugfs_free_inode(struct inode *inode) |
0db59e59 | 224 | { |
0db59e59 | 225 | if (S_ISLNK(inode->i_mode)) |
5723cb01 | 226 | kfree(inode->i_link); |
93b919da AV |
227 | free_inode_nonrcu(inode); |
228 | } | |
229 | ||
d6e48686 LN |
230 | static const struct super_operations debugfs_super_operations = { |
231 | .statfs = simple_statfs, | |
232 | .remount_fs = debugfs_remount, | |
233 | .show_options = debugfs_show_options, | |
6234ddf4 | 234 | .free_inode = debugfs_free_inode, |
d6e48686 LN |
235 | }; |
236 | ||
7c8d4698 NS |
237 | static void debugfs_release_dentry(struct dentry *dentry) |
238 | { | |
0ed04a18 | 239 | struct debugfs_fsdata *fsd = dentry->d_fsdata; |
7d39bc50 | 240 | |
0ed04a18 JB |
241 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) |
242 | return; | |
243 | ||
f4acfcd4 JB |
244 | /* check it wasn't a dir (no fsdata) or automount (no real_fops) */ |
245 | if (fsd && fsd->real_fops) { | |
8c88a474 JB |
246 | WARN_ON(!list_empty(&fsd->cancellations)); |
247 | mutex_destroy(&fsd->cancellations_mtx); | |
f4acfcd4 JB |
248 | } |
249 | ||
0ed04a18 | 250 | kfree(fsd); |
7c8d4698 NS |
251 | } |
252 | ||
77b3da6e AV |
253 | static struct vfsmount *debugfs_automount(struct path *path) |
254 | { | |
0ed04a18 JB |
255 | struct debugfs_fsdata *fsd = path->dentry->d_fsdata; |
256 | ||
257 | return fsd->automount(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
258 | } |
259 | ||
260 | static const struct dentry_operations debugfs_dops = { | |
261 | .d_delete = always_delete_dentry, | |
7c8d4698 | 262 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
263 | .d_automount = debugfs_automount, |
264 | }; | |
265 | ||
1da177e4 LT |
266 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
267 | { | |
cda37124 | 268 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
269 | struct debugfs_fs_info *fsi; |
270 | int err; | |
271 | ||
d6e48686 LN |
272 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
273 | sb->s_fs_info = fsi; | |
274 | if (!fsi) { | |
275 | err = -ENOMEM; | |
276 | goto fail; | |
277 | } | |
278 | ||
279 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
280 | if (err) | |
281 | goto fail; | |
282 | ||
283 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
284 | if (err) | |
285 | goto fail; | |
286 | ||
287 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 288 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
289 | |
290 | debugfs_apply_options(sb); | |
291 | ||
292 | return 0; | |
1da177e4 | 293 | |
d6e48686 LN |
294 | fail: |
295 | kfree(fsi); | |
296 | sb->s_fs_info = NULL; | |
297 | return err; | |
1da177e4 LT |
298 | } |
299 | ||
fc14f2fe | 300 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 301 | int flags, const char *dev_name, |
fc14f2fe | 302 | void *data) |
1da177e4 | 303 | { |
a24c6f7b PE |
304 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
305 | return ERR_PTR(-EPERM); | |
306 | ||
fc14f2fe | 307 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
308 | } |
309 | ||
310 | static struct file_system_type debug_fs_type = { | |
311 | .owner = THIS_MODULE, | |
312 | .name = "debugfs", | |
fc14f2fe | 313 | .mount = debug_mount, |
1da177e4 LT |
314 | .kill_sb = kill_litter_super, |
315 | }; | |
7f78e035 | 316 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 317 | |
a7c5437b OS |
318 | /** |
319 | * debugfs_lookup() - look up an existing debugfs file | |
320 | * @name: a pointer to a string containing the name of the file to look up. | |
321 | * @parent: a pointer to the parent dentry of the file. | |
322 | * | |
323 | * This function will return a pointer to a dentry if it succeeds. If the file | |
324 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
325 | * dentry must be passed to dput() when it is no longer needed. | |
326 | * | |
327 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
328 | * returned. | |
329 | */ | |
330 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
331 | { | |
332 | struct dentry *dentry; | |
333 | ||
bc6de804 | 334 | if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent)) |
a7c5437b OS |
335 | return NULL; |
336 | ||
337 | if (!parent) | |
338 | parent = debugfs_mount->mnt_root; | |
339 | ||
6c2d4798 | 340 | dentry = lookup_positive_unlocked(name, parent, strlen(name)); |
a7c5437b OS |
341 | if (IS_ERR(dentry)) |
342 | return NULL; | |
a7c5437b OS |
343 | return dentry; |
344 | } | |
345 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
346 | ||
190afd81 | 347 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 348 | { |
190afd81 | 349 | struct dentry *dentry; |
cfa57c11 AV |
350 | int error; |
351 | ||
a24c6f7b PE |
352 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
353 | return ERR_PTR(-EPERM); | |
354 | ||
56348560 GKH |
355 | if (!debugfs_initialized()) |
356 | return ERR_PTR(-ENOENT); | |
357 | ||
d03ae477 | 358 | pr_debug("creating file '%s'\n", name); |
cfa57c11 | 359 | |
c9e15f25 GK |
360 | if (IS_ERR(parent)) |
361 | return parent; | |
362 | ||
cfa57c11 AV |
363 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
364 | &debugfs_mount_count); | |
43e23b6c GKH |
365 | if (error) { |
366 | pr_err("Unable to pin filesystem for file '%s'\n", name); | |
190afd81 | 367 | return ERR_PTR(error); |
43e23b6c | 368 | } |
1da177e4 LT |
369 | |
370 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 371 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
372 | * block. A pointer to that is in the struct vfsmount that we |
373 | * have around. | |
374 | */ | |
ef52c75e | 375 | if (!parent) |
4c1d5a64 | 376 | parent = debugfs_mount->mnt_root; |
1da177e4 | 377 | |
5955102c | 378 | inode_lock(d_inode(parent)); |
a3d1e7eb AV |
379 | if (unlikely(IS_DEADDIR(d_inode(parent)))) |
380 | dentry = ERR_PTR(-ENOENT); | |
381 | else | |
382 | dentry = lookup_one_len(name, parent, strlen(name)); | |
2b0143b5 | 383 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
c33d4423 GKH |
384 | if (d_is_dir(dentry)) |
385 | pr_err("Directory '%s' with parent '%s' already present!\n", | |
386 | name, parent->d_name.name); | |
387 | else | |
388 | pr_err("File '%s' in directory '%s' already present!\n", | |
389 | name, parent->d_name.name); | |
cfa57c11 | 390 | dput(dentry); |
190afd81 AV |
391 | dentry = ERR_PTR(-EEXIST); |
392 | } | |
0ee9608c DB |
393 | |
394 | if (IS_ERR(dentry)) { | |
5955102c | 395 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
396 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
397 | } | |
398 | ||
190afd81 AV |
399 | return dentry; |
400 | } | |
401 | ||
5233e311 | 402 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 403 | { |
5955102c | 404 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 405 | dput(dentry); |
5233e311 | 406 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
ff9fb72b | 407 | return ERR_PTR(-ENOMEM); |
5233e311 | 408 | } |
1da177e4 | 409 | |
5233e311 AV |
410 | static struct dentry *end_creating(struct dentry *dentry) |
411 | { | |
5955102c | 412 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
413 | return dentry; |
414 | } | |
415 | ||
49d200de NS |
416 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
417 | struct dentry *parent, void *data, | |
418 | const struct file_operations *proxy_fops, | |
419 | const struct file_operations *real_fops) | |
420 | { | |
421 | struct dentry *dentry; | |
422 | struct inode *inode; | |
423 | ||
424 | if (!(mode & S_IFMT)) | |
425 | mode |= S_IFREG; | |
426 | BUG_ON(!S_ISREG(mode)); | |
427 | dentry = start_creating(name, parent); | |
428 | ||
7d39bc50 | 429 | if (IS_ERR(dentry)) |
ff9fb72b | 430 | return dentry; |
49d200de | 431 | |
a24c6f7b PE |
432 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
433 | failed_creating(dentry); | |
434 | return ERR_PTR(-EPERM); | |
435 | } | |
436 | ||
49d200de | 437 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
438 | if (unlikely(!inode)) { |
439 | pr_err("out of free dentries, can not create file '%s'\n", | |
440 | name); | |
49d200de | 441 | return failed_creating(dentry); |
43e23b6c | 442 | } |
49d200de NS |
443 | |
444 | inode->i_mode = mode; | |
445 | inode->i_private = data; | |
446 | ||
5496197f | 447 | inode->i_op = &debugfs_file_inode_operations; |
49d200de | 448 | inode->i_fop = proxy_fops; |
7d39bc50 NS |
449 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
450 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
451 | |
452 | d_instantiate(dentry, inode); | |
453 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
454 | return end_creating(dentry); | |
455 | } | |
456 | ||
1da177e4 LT |
457 | /** |
458 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 459 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 460 | * @mode: the permission that the file should have. |
1da177e4 | 461 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 462 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
463 | * file will be created in the root of the debugfs filesystem. |
464 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 465 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
466 | * the open() call. |
467 | * @fops: a pointer to a struct file_operations that should be used for | |
468 | * this file. | |
469 | * | |
470 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
471 | * wide range of flexibility in creating a file, or a directory (if you want |
472 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
473 | * recommended to be used instead.) |
474 | * | |
475 | * This function will return a pointer to a dentry if it succeeds. This | |
476 | * pointer must be passed to the debugfs_remove() function when the file is | |
477 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 478 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 479 | * returned. |
1da177e4 | 480 | * |
6468b3af | 481 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 482 | * returned. |
8bcbde2b DA |
483 | * |
484 | * NOTE: it's expected that most callers should _ignore_ the errors returned | |
485 | * by this function. Other debugfs functions handle the fact that the "dentry" | |
486 | * passed to them could be an error and they don't crash in that case. | |
487 | * Drivers should generally work fine even if debugfs fails to init anyway. | |
1da177e4 | 488 | */ |
f4ae40a6 | 489 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 490 | struct dentry *parent, void *data, |
99ac48f5 | 491 | const struct file_operations *fops) |
1da177e4 | 492 | { |
680b3024 | 493 | |
49d200de NS |
494 | return __debugfs_create_file(name, mode, parent, data, |
495 | fops ? &debugfs_full_proxy_file_operations : | |
496 | &debugfs_noop_file_operations, | |
497 | fops); | |
498 | } | |
499 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 500 | |
c6468808 NS |
501 | /** |
502 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
503 | * @name: a pointer to a string containing the name of the file to create. | |
504 | * @mode: the permission that the file should have. | |
505 | * @parent: a pointer to the parent dentry for this file. This should be a | |
506 | * directory dentry if set. If this parameter is NULL, then the | |
507 | * file will be created in the root of the debugfs filesystem. | |
508 | * @data: a pointer to something that the caller will want to get to later | |
509 | * on. The inode.i_private pointer will point to this value on | |
510 | * the open() call. | |
511 | * @fops: a pointer to a struct file_operations that should be used for | |
512 | * this file. | |
513 | * | |
514 | * debugfs_create_file_unsafe() is completely analogous to | |
515 | * debugfs_create_file(), the only difference being that the fops | |
516 | * handed it will not get protected against file removals by the | |
517 | * debugfs core. | |
518 | * | |
519 | * It is your responsibility to protect your struct file_operation | |
0eeb2731 SS |
520 | * methods against file removals by means of debugfs_file_get() |
521 | * and debugfs_file_put(). ->open() is still protected by | |
c6468808 NS |
522 | * debugfs though. |
523 | * | |
524 | * Any struct file_operations defined by means of | |
525 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
526 | * thus, may be used here. | |
527 | */ | |
49d200de NS |
528 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
529 | struct dentry *parent, void *data, | |
530 | const struct file_operations *fops) | |
531 | { | |
9fd4dcec | 532 | |
49d200de NS |
533 | return __debugfs_create_file(name, mode, parent, data, |
534 | fops ? &debugfs_open_proxy_file_operations : | |
535 | &debugfs_noop_file_operations, | |
536 | fops); | |
1da177e4 | 537 | } |
c6468808 | 538 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 539 | |
e59b4e91 DH |
540 | /** |
541 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
542 | * @name: a pointer to a string containing the name of the file to create. | |
543 | * @mode: the permission that the file should have. | |
544 | * @parent: a pointer to the parent dentry for this file. This should be a | |
545 | * directory dentry if set. If this parameter is NULL, then the | |
546 | * file will be created in the root of the debugfs filesystem. | |
547 | * @data: a pointer to something that the caller will want to get to later | |
548 | * on. The inode.i_private pointer will point to this value on | |
549 | * the open() call. | |
550 | * @fops: a pointer to a struct file_operations that should be used for | |
551 | * this file. | |
552 | * @file_size: initial file size | |
553 | * | |
554 | * This is the basic "create a file" function for debugfs. It allows for a | |
555 | * wide range of flexibility in creating a file, or a directory (if you want | |
556 | * to create a directory, the debugfs_create_dir() function is | |
557 | * recommended to be used instead.) | |
e59b4e91 | 558 | */ |
526ee72d GKH |
559 | void debugfs_create_file_size(const char *name, umode_t mode, |
560 | struct dentry *parent, void *data, | |
561 | const struct file_operations *fops, | |
562 | loff_t file_size) | |
e59b4e91 DH |
563 | { |
564 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
565 | ||
af505cad | 566 | if (!IS_ERR(de)) |
2b0143b5 | 567 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
568 | } |
569 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
570 | ||
1da177e4 LT |
571 | /** |
572 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
573 | * @name: a pointer to a string containing the name of the directory to |
574 | * create. | |
575 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 576 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
577 | * directory will be created in the root of the debugfs filesystem. |
578 | * | |
579 | * This function creates a directory in debugfs with the given name. | |
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 file is | |
583 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 584 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 585 | * returned. |
1da177e4 | 586 | * |
6468b3af | 587 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 588 | * returned. |
8bcbde2b DA |
589 | * |
590 | * NOTE: it's expected that most callers should _ignore_ the errors returned | |
591 | * by this function. Other debugfs functions handle the fact that the "dentry" | |
592 | * passed to them could be an error and they don't crash in that case. | |
593 | * Drivers should generally work fine even if debugfs fails to init anyway. | |
1da177e4 LT |
594 | */ |
595 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
596 | { | |
ad5abd5b | 597 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 598 | struct inode *inode; |
ad5abd5b AV |
599 | |
600 | if (IS_ERR(dentry)) | |
ff9fb72b | 601 | return dentry; |
ad5abd5b | 602 | |
a24c6f7b PE |
603 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
604 | failed_creating(dentry); | |
605 | return ERR_PTR(-EPERM); | |
606 | } | |
607 | ||
edac65ea | 608 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
609 | if (unlikely(!inode)) { |
610 | pr_err("out of free dentries, can not create directory '%s'\n", | |
611 | name); | |
5233e311 | 612 | return failed_creating(dentry); |
43e23b6c | 613 | } |
680b3024 | 614 | |
f5b7769e | 615 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
5496197f | 616 | inode->i_op = &debugfs_dir_inode_operations; |
edac65ea AV |
617 | inode->i_fop = &simple_dir_operations; |
618 | ||
619 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
620 | inc_nlink(inode); | |
680b3024 | 621 | d_instantiate(dentry, inode); |
2b0143b5 DH |
622 | inc_nlink(d_inode(dentry->d_parent)); |
623 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 624 | return end_creating(dentry); |
1da177e4 LT |
625 | } |
626 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
627 | ||
77b3da6e AV |
628 | /** |
629 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
630 | * @name: a pointer to a string containing the name of the file to create. | |
631 | * @parent: a pointer to the parent dentry for this file. This should be a | |
632 | * directory dentry if set. If this parameter is NULL, then the | |
633 | * file will be created in the root of the debugfs filesystem. | |
634 | * @f: function to be called when pathname resolution steps on that one. | |
635 | * @data: opaque argument to pass to f(). | |
636 | * | |
637 | * @f should return what ->d_automount() would. | |
638 | */ | |
639 | struct dentry *debugfs_create_automount(const char *name, | |
640 | struct dentry *parent, | |
93faccbb | 641 | debugfs_automount_t f, |
77b3da6e AV |
642 | void *data) |
643 | { | |
644 | struct dentry *dentry = start_creating(name, parent); | |
0ed04a18 | 645 | struct debugfs_fsdata *fsd; |
77b3da6e AV |
646 | struct inode *inode; |
647 | ||
648 | if (IS_ERR(dentry)) | |
ff9fb72b | 649 | return dentry; |
77b3da6e | 650 | |
0ed04a18 JB |
651 | fsd = kzalloc(sizeof(*fsd), GFP_KERNEL); |
652 | if (!fsd) { | |
653 | failed_creating(dentry); | |
654 | return ERR_PTR(-ENOMEM); | |
655 | } | |
656 | ||
657 | fsd->automount = f; | |
658 | ||
a24c6f7b PE |
659 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
660 | failed_creating(dentry); | |
0ed04a18 | 661 | kfree(fsd); |
a24c6f7b PE |
662 | return ERR_PTR(-EPERM); |
663 | } | |
664 | ||
77b3da6e | 665 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
666 | if (unlikely(!inode)) { |
667 | pr_err("out of free dentries, can not create automount '%s'\n", | |
668 | name); | |
0ed04a18 | 669 | kfree(fsd); |
77b3da6e | 670 | return failed_creating(dentry); |
43e23b6c | 671 | } |
77b3da6e | 672 | |
87243deb | 673 | make_empty_dir_inode(inode); |
77b3da6e AV |
674 | inode->i_flags |= S_AUTOMOUNT; |
675 | inode->i_private = data; | |
0ed04a18 | 676 | dentry->d_fsdata = fsd; |
a8f324a4 RP |
677 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
678 | inc_nlink(inode); | |
77b3da6e | 679 | d_instantiate(dentry, inode); |
a8f324a4 RP |
680 | inc_nlink(d_inode(dentry->d_parent)); |
681 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
682 | return end_creating(dentry); |
683 | } | |
684 | EXPORT_SYMBOL(debugfs_create_automount); | |
685 | ||
66f54963 PO |
686 | /** |
687 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
688 | * @name: a pointer to a string containing the name of the symbolic link to | |
689 | * create. | |
690 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 691 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
692 | * then the symbolic link will be created in the root of the debugfs |
693 | * filesystem. | |
694 | * @target: a pointer to a string containing the path to the target of the | |
695 | * symbolic link. | |
696 | * | |
697 | * This function creates a symbolic link with the given name in debugfs that | |
698 | * links to the given target path. | |
699 | * | |
700 | * This function will return a pointer to a dentry if it succeeds. This | |
701 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
702 | * link is to be removed (no automatic cleanup happens if your module is | |
adc92dd4 | 703 | * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR) |
ff9fb72b | 704 | * will be returned. |
66f54963 PO |
705 | * |
706 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 707 | * returned. |
66f54963 PO |
708 | */ |
709 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
710 | const char *target) | |
711 | { | |
ad5abd5b | 712 | struct dentry *dentry; |
680b3024 AV |
713 | struct inode *inode; |
714 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 | 715 | if (!link) |
ff9fb72b | 716 | return ERR_PTR(-ENOMEM); |
66f54963 | 717 | |
ad5abd5b | 718 | dentry = start_creating(name, parent); |
ad5abd5b | 719 | if (IS_ERR(dentry)) { |
66f54963 | 720 | kfree(link); |
ff9fb72b | 721 | return dentry; |
ad5abd5b AV |
722 | } |
723 | ||
edac65ea | 724 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 725 | if (unlikely(!inode)) { |
43e23b6c GKH |
726 | pr_err("out of free dentries, can not create symlink '%s'\n", |
727 | name); | |
ad5abd5b | 728 | kfree(link); |
5233e311 | 729 | return failed_creating(dentry); |
680b3024 | 730 | } |
edac65ea | 731 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5496197f | 732 | inode->i_op = &debugfs_symlink_inode_operations; |
5723cb01 | 733 | inode->i_link = link; |
680b3024 | 734 | d_instantiate(dentry, inode); |
5233e311 | 735 | return end_creating(dentry); |
66f54963 PO |
736 | } |
737 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
738 | ||
823e545c | 739 | static void __debugfs_file_removed(struct dentry *dentry) |
e9117a5a NS |
740 | { |
741 | struct debugfs_fsdata *fsd; | |
742 | ||
7d39bc50 NS |
743 | /* |
744 | * Paired with the closing smp_mb() implied by a successful | |
745 | * cmpxchg() in debugfs_file_get(): either | |
746 | * debugfs_file_get() must see a dead dentry or we must see a | |
747 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
748 | */ | |
749 | smp_mb(); | |
750 | fsd = READ_ONCE(dentry->d_fsdata); | |
751 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
752 | return; | |
f4acfcd4 | 753 | |
8c88a474 JB |
754 | /* if we hit zero, just wait for all to finish */ |
755 | if (!refcount_dec_and_test(&fsd->active_users)) { | |
e9117a5a | 756 | wait_for_completion(&fsd->active_users_drained); |
8c88a474 JB |
757 | return; |
758 | } | |
759 | ||
760 | /* if we didn't hit zero, try to cancel any we can */ | |
761 | while (refcount_read(&fsd->active_users)) { | |
762 | struct debugfs_cancellation *c; | |
763 | ||
764 | /* | |
765 | * Lock the cancellations. Note that the cancellations | |
766 | * structs are meant to be on the stack, so we need to | |
767 | * ensure we either use them here or don't touch them, | |
768 | * and debugfs_leave_cancellation() will wait for this | |
769 | * to be finished processing before exiting one. It may | |
770 | * of course win and remove the cancellation, but then | |
771 | * chances are we never even got into this bit, we only | |
772 | * do if the refcount isn't zero already. | |
773 | */ | |
774 | mutex_lock(&fsd->cancellations_mtx); | |
775 | while ((c = list_first_entry_or_null(&fsd->cancellations, | |
776 | typeof(*c), list))) { | |
777 | list_del_init(&c->list); | |
778 | c->cancel(dentry, c->cancel_data); | |
779 | } | |
780 | mutex_unlock(&fsd->cancellations_mtx); | |
781 | ||
e9117a5a | 782 | wait_for_completion(&fsd->active_users_drained); |
8c88a474 | 783 | } |
e9117a5a NS |
784 | } |
785 | ||
a3d1e7eb | 786 | static void remove_one(struct dentry *victim) |
9505e637 | 787 | { |
a3d1e7eb AV |
788 | if (d_is_reg(victim)) |
789 | __debugfs_file_removed(victim); | |
790 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 | 791 | } |
9505e637 HS |
792 | |
793 | /** | |
a3d1e7eb | 794 | * debugfs_remove - recursively removes a directory |
398dc4ad UM |
795 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
796 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
797 | * |
798 | * This function recursively removes a directory tree in debugfs that | |
799 | * was previously created with a call to another debugfs function | |
800 | * (like debugfs_create_file() or variants thereof.) | |
801 | * | |
802 | * This function is required to be called in order for the file to be | |
803 | * removed, no automatic cleanup of files will happen when a module is | |
804 | * removed, you are responsible here. | |
805 | */ | |
a3d1e7eb | 806 | void debugfs_remove(struct dentry *dentry) |
9505e637 | 807 | { |
a59d6293 | 808 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
809 | return; |
810 | ||
a3d1e7eb AV |
811 | simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count); |
812 | simple_recursive_removal(dentry, remove_one); | |
813 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1da177e4 | 814 | } |
a3d1e7eb | 815 | EXPORT_SYMBOL_GPL(debugfs_remove); |
1da177e4 | 816 | |
dec9b2f1 GKH |
817 | /** |
818 | * debugfs_lookup_and_remove - lookup a directory or file and recursively remove it | |
819 | * @name: a pointer to a string containing the name of the item to look up. | |
820 | * @parent: a pointer to the parent dentry of the item. | |
821 | * | |
822 | * This is the equlivant of doing something like | |
823 | * debugfs_remove(debugfs_lookup(..)) but with the proper reference counting | |
824 | * handled for the directory being looked up. | |
825 | */ | |
826 | void debugfs_lookup_and_remove(const char *name, struct dentry *parent) | |
827 | { | |
828 | struct dentry *dentry; | |
829 | ||
830 | dentry = debugfs_lookup(name, parent); | |
831 | if (!dentry) | |
832 | return; | |
833 | ||
834 | debugfs_remove(dentry); | |
835 | dput(dentry); | |
836 | } | |
837 | EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove); | |
838 | ||
cfc94cdf JK |
839 | /** |
840 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
841 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
842 | * should be a directory dentry. | |
843 | * @old_dentry: dentry of an object to be renamed. | |
844 | * @new_dir: a pointer to the parent dentry where the object should be | |
845 | * moved. This should be a directory dentry. | |
846 | * @new_name: a pointer to a string containing the target name. | |
847 | * | |
848 | * This function renames a file/directory in debugfs. The target must not | |
849 | * exist for rename to succeed. | |
850 | * | |
851 | * This function will return a pointer to old_dentry (which is updated to | |
88cd618d | 852 | * reflect renaming) if it succeeds. If an error occurs, ERR_PTR(-ERROR) |
d3002468 | 853 | * will be returned. |
cfc94cdf JK |
854 | * |
855 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
856 | * returned. | |
857 | */ | |
858 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
859 | struct dentry *new_dir, const char *new_name) | |
860 | { | |
861 | int error; | |
862 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 863 | struct name_snapshot old_name; |
cfc94cdf | 864 | |
d88c93f0 GKH |
865 | if (IS_ERR(old_dir)) |
866 | return old_dir; | |
867 | if (IS_ERR(new_dir)) | |
868 | return new_dir; | |
869 | if (IS_ERR_OR_NULL(old_dentry)) | |
870 | return old_dentry; | |
871 | ||
cfc94cdf JK |
872 | trap = lock_rename(new_dir, old_dir); |
873 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 874 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
875 | goto exit; |
876 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 877 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
878 | d_mountpoint(old_dentry)) |
879 | goto exit; | |
880 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
881 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 882 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
883 | goto exit; |
884 | ||
49d31c2f | 885 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 886 | |
e18275ae | 887 | error = simple_rename(&nop_mnt_idmap, d_inode(old_dir), old_dentry, |
549c7297 | 888 | d_inode(new_dir), dentry, 0); |
cfc94cdf | 889 | if (error) { |
49d31c2f | 890 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
891 | goto exit; |
892 | } | |
893 | d_move(old_dentry, dentry); | |
f4ec3a3d | 894 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, |
e36cb0b8 | 895 | d_is_dir(old_dentry), |
5a190ae6 | 896 | NULL, old_dentry); |
49d31c2f | 897 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
898 | unlock_rename(new_dir, old_dir); |
899 | dput(dentry); | |
900 | return old_dentry; | |
901 | exit: | |
902 | if (dentry && !IS_ERR(dentry)) | |
903 | dput(dentry); | |
904 | unlock_rename(new_dir, old_dir); | |
ff9fb72b GKH |
905 | if (IS_ERR(dentry)) |
906 | return dentry; | |
907 | return ERR_PTR(-EINVAL); | |
cfc94cdf JK |
908 | } |
909 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
910 | ||
c0f92ba9 FW |
911 | /** |
912 | * debugfs_initialized - Tells whether debugfs has been registered | |
913 | */ | |
914 | bool debugfs_initialized(void) | |
915 | { | |
916 | return debugfs_registered; | |
917 | } | |
918 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
919 | ||
a24c6f7b PE |
920 | static int __init debugfs_kernel(char *str) |
921 | { | |
922 | if (str) { | |
923 | if (!strcmp(str, "on")) | |
924 | debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT; | |
925 | else if (!strcmp(str, "no-mount")) | |
926 | debugfs_allow = DEBUGFS_ALLOW_API; | |
927 | else if (!strcmp(str, "off")) | |
928 | debugfs_allow = 0; | |
929 | } | |
930 | ||
931 | return 0; | |
932 | } | |
933 | early_param("debugfs", debugfs_kernel); | |
1da177e4 LT |
934 | static int __init debugfs_init(void) |
935 | { | |
936 | int retval; | |
937 | ||
a24c6f7b PE |
938 | if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT)) |
939 | return -EPERM; | |
940 | ||
f9bb4882 EB |
941 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
942 | if (retval) | |
943 | return retval; | |
1da177e4 LT |
944 | |
945 | retval = register_filesystem(&debug_fs_type); | |
946 | if (retval) | |
f9bb4882 | 947 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
948 | else |
949 | debugfs_registered = true; | |
950 | ||
1da177e4 LT |
951 | return retval; |
952 | } | |
1da177e4 | 953 | core_initcall(debugfs_init); |