Commit | Line | Data |
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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 | 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 | */ | |
549c7297 CB |
45 | static int debugfs_setattr(struct user_namespace *mnt_userns, |
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 | } | |
549c7297 | 55 | return simple_setattr(&init_user_ns, 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(); |
1b48b530 | 75 | inode->i_atime = inode->i_mtime = |
c2050a45 | 76 | inode->i_ctime = current_time(inode); |
1da177e4 | 77 | } |
88e412ea | 78 | return inode; |
1da177e4 LT |
79 | } |
80 | ||
d6e48686 | 81 | struct debugfs_mount_opts { |
7dc05881 EB |
82 | kuid_t uid; |
83 | kgid_t gid; | |
d6e48686 | 84 | umode_t mode; |
b8de524c BN |
85 | /* Opt_* bitfield. */ |
86 | unsigned int opts; | |
d6e48686 LN |
87 | }; |
88 | ||
89 | enum { | |
90 | Opt_uid, | |
91 | Opt_gid, | |
92 | Opt_mode, | |
93 | Opt_err | |
94 | }; | |
95 | ||
96 | static const match_table_t tokens = { | |
97 | {Opt_uid, "uid=%u"}, | |
98 | {Opt_gid, "gid=%u"}, | |
99 | {Opt_mode, "mode=%o"}, | |
100 | {Opt_err, NULL} | |
101 | }; | |
102 | ||
103 | struct debugfs_fs_info { | |
104 | struct debugfs_mount_opts mount_opts; | |
105 | }; | |
106 | ||
107 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
108 | { | |
109 | substring_t args[MAX_OPT_ARGS]; | |
110 | int option; | |
111 | int token; | |
7dc05881 EB |
112 | kuid_t uid; |
113 | kgid_t gid; | |
d6e48686 LN |
114 | char *p; |
115 | ||
b8de524c | 116 | opts->opts = 0; |
d6e48686 LN |
117 | opts->mode = DEBUGFS_DEFAULT_MODE; |
118 | ||
119 | while ((p = strsep(&data, ",")) != NULL) { | |
120 | if (!*p) | |
121 | continue; | |
122 | ||
123 | token = match_token(p, tokens, args); | |
124 | switch (token) { | |
125 | case Opt_uid: | |
126 | if (match_int(&args[0], &option)) | |
127 | return -EINVAL; | |
7dc05881 EB |
128 | uid = make_kuid(current_user_ns(), option); |
129 | if (!uid_valid(uid)) | |
130 | return -EINVAL; | |
131 | opts->uid = uid; | |
d6e48686 LN |
132 | break; |
133 | case Opt_gid: | |
f1688e04 | 134 | if (match_int(&args[0], &option)) |
d6e48686 | 135 | return -EINVAL; |
7dc05881 EB |
136 | gid = make_kgid(current_user_ns(), option); |
137 | if (!gid_valid(gid)) | |
138 | return -EINVAL; | |
139 | opts->gid = gid; | |
d6e48686 LN |
140 | break; |
141 | case Opt_mode: | |
142 | if (match_octal(&args[0], &option)) | |
143 | return -EINVAL; | |
144 | opts->mode = option & S_IALLUGO; | |
145 | break; | |
146 | /* | |
147 | * We might like to report bad mount options here; | |
148 | * but traditionally debugfs has ignored all mount options | |
149 | */ | |
150 | } | |
b8de524c BN |
151 | |
152 | opts->opts |= BIT(token); | |
d6e48686 LN |
153 | } |
154 | ||
155 | return 0; | |
156 | } | |
157 | ||
b8de524c | 158 | static void _debugfs_apply_options(struct super_block *sb, bool remount) |
d6e48686 LN |
159 | { |
160 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 161 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
162 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
163 | ||
b8de524c BN |
164 | /* |
165 | * On remount, only reset mode/uid/gid if they were provided as mount | |
166 | * options. | |
167 | */ | |
d6e48686 | 168 | |
b8de524c BN |
169 | if (!remount || opts->opts & BIT(Opt_mode)) { |
170 | inode->i_mode &= ~S_IALLUGO; | |
171 | inode->i_mode |= opts->mode; | |
172 | } | |
d6e48686 | 173 | |
b8de524c BN |
174 | if (!remount || opts->opts & BIT(Opt_uid)) |
175 | inode->i_uid = opts->uid; | |
176 | ||
177 | if (!remount || opts->opts & BIT(Opt_gid)) | |
178 | inode->i_gid = opts->gid; | |
179 | } | |
180 | ||
181 | static void debugfs_apply_options(struct super_block *sb) | |
182 | { | |
183 | _debugfs_apply_options(sb, false); | |
184 | } | |
185 | ||
186 | static void debugfs_apply_options_remount(struct super_block *sb) | |
187 | { | |
188 | _debugfs_apply_options(sb, true); | |
d6e48686 LN |
189 | } |
190 | ||
191 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
192 | { | |
193 | int err; | |
194 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
195 | ||
02b9984d | 196 | sync_filesystem(sb); |
d6e48686 LN |
197 | err = debugfs_parse_options(data, &fsi->mount_opts); |
198 | if (err) | |
199 | goto fail; | |
200 | ||
b8de524c | 201 | debugfs_apply_options_remount(sb); |
d6e48686 LN |
202 | |
203 | fail: | |
204 | return err; | |
205 | } | |
206 | ||
207 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
208 | { | |
209 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
210 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
211 | ||
7dc05881 EB |
212 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
213 | seq_printf(m, ",uid=%u", | |
214 | from_kuid_munged(&init_user_ns, opts->uid)); | |
215 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
216 | seq_printf(m, ",gid=%u", | |
217 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
218 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
219 | seq_printf(m, ",mode=%o", opts->mode); | |
220 | ||
221 | return 0; | |
222 | } | |
223 | ||
6234ddf4 | 224 | static void debugfs_free_inode(struct inode *inode) |
0db59e59 | 225 | { |
0db59e59 | 226 | if (S_ISLNK(inode->i_mode)) |
5723cb01 | 227 | kfree(inode->i_link); |
93b919da AV |
228 | free_inode_nonrcu(inode); |
229 | } | |
230 | ||
d6e48686 LN |
231 | static const struct super_operations debugfs_super_operations = { |
232 | .statfs = simple_statfs, | |
233 | .remount_fs = debugfs_remount, | |
234 | .show_options = debugfs_show_options, | |
6234ddf4 | 235 | .free_inode = debugfs_free_inode, |
d6e48686 LN |
236 | }; |
237 | ||
7c8d4698 NS |
238 | static void debugfs_release_dentry(struct dentry *dentry) |
239 | { | |
7d39bc50 NS |
240 | void *fsd = dentry->d_fsdata; |
241 | ||
242 | if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) | |
243 | kfree(dentry->d_fsdata); | |
7c8d4698 NS |
244 | } |
245 | ||
77b3da6e AV |
246 | static struct vfsmount *debugfs_automount(struct path *path) |
247 | { | |
93faccbb EB |
248 | debugfs_automount_t f; |
249 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
250 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
251 | } |
252 | ||
253 | static const struct dentry_operations debugfs_dops = { | |
254 | .d_delete = always_delete_dentry, | |
7c8d4698 | 255 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
256 | .d_automount = debugfs_automount, |
257 | }; | |
258 | ||
1da177e4 LT |
259 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
260 | { | |
cda37124 | 261 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
262 | struct debugfs_fs_info *fsi; |
263 | int err; | |
264 | ||
d6e48686 LN |
265 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
266 | sb->s_fs_info = fsi; | |
267 | if (!fsi) { | |
268 | err = -ENOMEM; | |
269 | goto fail; | |
270 | } | |
271 | ||
272 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
273 | if (err) | |
274 | goto fail; | |
275 | ||
276 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
277 | if (err) | |
278 | goto fail; | |
279 | ||
280 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 281 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
282 | |
283 | debugfs_apply_options(sb); | |
284 | ||
285 | return 0; | |
1da177e4 | 286 | |
d6e48686 LN |
287 | fail: |
288 | kfree(fsi); | |
289 | sb->s_fs_info = NULL; | |
290 | return err; | |
1da177e4 LT |
291 | } |
292 | ||
fc14f2fe | 293 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 294 | int flags, const char *dev_name, |
fc14f2fe | 295 | void *data) |
1da177e4 | 296 | { |
a24c6f7b PE |
297 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
298 | return ERR_PTR(-EPERM); | |
299 | ||
fc14f2fe | 300 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
301 | } |
302 | ||
303 | static struct file_system_type debug_fs_type = { | |
304 | .owner = THIS_MODULE, | |
305 | .name = "debugfs", | |
fc14f2fe | 306 | .mount = debug_mount, |
1da177e4 LT |
307 | .kill_sb = kill_litter_super, |
308 | }; | |
7f78e035 | 309 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 310 | |
a7c5437b OS |
311 | /** |
312 | * debugfs_lookup() - look up an existing debugfs file | |
313 | * @name: a pointer to a string containing the name of the file to look up. | |
314 | * @parent: a pointer to the parent dentry of the file. | |
315 | * | |
316 | * This function will return a pointer to a dentry if it succeeds. If the file | |
317 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
318 | * dentry must be passed to dput() when it is no longer needed. | |
319 | * | |
320 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
321 | * returned. | |
322 | */ | |
323 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
324 | { | |
325 | struct dentry *dentry; | |
326 | ||
bc6de804 | 327 | if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent)) |
a7c5437b OS |
328 | return NULL; |
329 | ||
330 | if (!parent) | |
331 | parent = debugfs_mount->mnt_root; | |
332 | ||
6c2d4798 | 333 | dentry = lookup_positive_unlocked(name, parent, strlen(name)); |
a7c5437b OS |
334 | if (IS_ERR(dentry)) |
335 | return NULL; | |
a7c5437b OS |
336 | return dentry; |
337 | } | |
338 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
339 | ||
190afd81 | 340 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 341 | { |
190afd81 | 342 | struct dentry *dentry; |
cfa57c11 AV |
343 | int error; |
344 | ||
a24c6f7b PE |
345 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
346 | return ERR_PTR(-EPERM); | |
347 | ||
56348560 GKH |
348 | if (!debugfs_initialized()) |
349 | return ERR_PTR(-ENOENT); | |
350 | ||
d03ae477 | 351 | pr_debug("creating file '%s'\n", name); |
cfa57c11 | 352 | |
c9e15f25 GK |
353 | if (IS_ERR(parent)) |
354 | return parent; | |
355 | ||
cfa57c11 AV |
356 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
357 | &debugfs_mount_count); | |
43e23b6c GKH |
358 | if (error) { |
359 | pr_err("Unable to pin filesystem for file '%s'\n", name); | |
190afd81 | 360 | return ERR_PTR(error); |
43e23b6c | 361 | } |
1da177e4 LT |
362 | |
363 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 364 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
365 | * block. A pointer to that is in the struct vfsmount that we |
366 | * have around. | |
367 | */ | |
ef52c75e | 368 | if (!parent) |
4c1d5a64 | 369 | parent = debugfs_mount->mnt_root; |
1da177e4 | 370 | |
5955102c | 371 | inode_lock(d_inode(parent)); |
a3d1e7eb AV |
372 | if (unlikely(IS_DEADDIR(d_inode(parent)))) |
373 | dentry = ERR_PTR(-ENOENT); | |
374 | else | |
375 | dentry = lookup_one_len(name, parent, strlen(name)); | |
2b0143b5 | 376 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
c33d4423 GKH |
377 | if (d_is_dir(dentry)) |
378 | pr_err("Directory '%s' with parent '%s' already present!\n", | |
379 | name, parent->d_name.name); | |
380 | else | |
381 | pr_err("File '%s' in directory '%s' already present!\n", | |
382 | name, parent->d_name.name); | |
cfa57c11 | 383 | dput(dentry); |
190afd81 AV |
384 | dentry = ERR_PTR(-EEXIST); |
385 | } | |
0ee9608c DB |
386 | |
387 | if (IS_ERR(dentry)) { | |
5955102c | 388 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
389 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
390 | } | |
391 | ||
190afd81 AV |
392 | return dentry; |
393 | } | |
394 | ||
5233e311 | 395 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 396 | { |
5955102c | 397 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 398 | dput(dentry); |
5233e311 | 399 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
ff9fb72b | 400 | return ERR_PTR(-ENOMEM); |
5233e311 | 401 | } |
1da177e4 | 402 | |
5233e311 AV |
403 | static struct dentry *end_creating(struct dentry *dentry) |
404 | { | |
5955102c | 405 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
406 | return dentry; |
407 | } | |
408 | ||
49d200de NS |
409 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
410 | struct dentry *parent, void *data, | |
411 | const struct file_operations *proxy_fops, | |
412 | const struct file_operations *real_fops) | |
413 | { | |
414 | struct dentry *dentry; | |
415 | struct inode *inode; | |
416 | ||
417 | if (!(mode & S_IFMT)) | |
418 | mode |= S_IFREG; | |
419 | BUG_ON(!S_ISREG(mode)); | |
420 | dentry = start_creating(name, parent); | |
421 | ||
7d39bc50 | 422 | if (IS_ERR(dentry)) |
ff9fb72b | 423 | return dentry; |
49d200de | 424 | |
a24c6f7b PE |
425 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
426 | failed_creating(dentry); | |
427 | return ERR_PTR(-EPERM); | |
428 | } | |
429 | ||
49d200de | 430 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
431 | if (unlikely(!inode)) { |
432 | pr_err("out of free dentries, can not create file '%s'\n", | |
433 | name); | |
49d200de | 434 | return failed_creating(dentry); |
43e23b6c | 435 | } |
49d200de NS |
436 | |
437 | inode->i_mode = mode; | |
438 | inode->i_private = data; | |
439 | ||
5496197f | 440 | inode->i_op = &debugfs_file_inode_operations; |
49d200de | 441 | inode->i_fop = proxy_fops; |
7d39bc50 NS |
442 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
443 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
444 | |
445 | d_instantiate(dentry, inode); | |
446 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
447 | return end_creating(dentry); | |
448 | } | |
449 | ||
1da177e4 LT |
450 | /** |
451 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 452 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 453 | * @mode: the permission that the file should have. |
1da177e4 | 454 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 455 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
456 | * file will be created in the root of the debugfs filesystem. |
457 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 458 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
459 | * the open() call. |
460 | * @fops: a pointer to a struct file_operations that should be used for | |
461 | * this file. | |
462 | * | |
463 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
464 | * wide range of flexibility in creating a file, or a directory (if you want |
465 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
466 | * recommended to be used instead.) |
467 | * | |
468 | * This function will return a pointer to a dentry if it succeeds. This | |
469 | * pointer must be passed to the debugfs_remove() function when the file is | |
470 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 471 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 472 | * returned. |
1da177e4 | 473 | * |
6468b3af | 474 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 475 | * returned. |
8bcbde2b DA |
476 | * |
477 | * NOTE: it's expected that most callers should _ignore_ the errors returned | |
478 | * by this function. Other debugfs functions handle the fact that the "dentry" | |
479 | * passed to them could be an error and they don't crash in that case. | |
480 | * Drivers should generally work fine even if debugfs fails to init anyway. | |
1da177e4 | 481 | */ |
f4ae40a6 | 482 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 483 | struct dentry *parent, void *data, |
99ac48f5 | 484 | const struct file_operations *fops) |
1da177e4 | 485 | { |
680b3024 | 486 | |
49d200de NS |
487 | return __debugfs_create_file(name, mode, parent, data, |
488 | fops ? &debugfs_full_proxy_file_operations : | |
489 | &debugfs_noop_file_operations, | |
490 | fops); | |
491 | } | |
492 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 493 | |
c6468808 NS |
494 | /** |
495 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
496 | * @name: a pointer to a string containing the name of the file to create. | |
497 | * @mode: the permission that the file should have. | |
498 | * @parent: a pointer to the parent dentry for this file. This should be a | |
499 | * directory dentry if set. If this parameter is NULL, then the | |
500 | * file will be created in the root of the debugfs filesystem. | |
501 | * @data: a pointer to something that the caller will want to get to later | |
502 | * on. The inode.i_private pointer will point to this value on | |
503 | * the open() call. | |
504 | * @fops: a pointer to a struct file_operations that should be used for | |
505 | * this file. | |
506 | * | |
507 | * debugfs_create_file_unsafe() is completely analogous to | |
508 | * debugfs_create_file(), the only difference being that the fops | |
509 | * handed it will not get protected against file removals by the | |
510 | * debugfs core. | |
511 | * | |
512 | * It is your responsibility to protect your struct file_operation | |
0eeb2731 SS |
513 | * methods against file removals by means of debugfs_file_get() |
514 | * and debugfs_file_put(). ->open() is still protected by | |
c6468808 NS |
515 | * debugfs though. |
516 | * | |
517 | * Any struct file_operations defined by means of | |
518 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
519 | * thus, may be used here. | |
520 | */ | |
49d200de NS |
521 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
522 | struct dentry *parent, void *data, | |
523 | const struct file_operations *fops) | |
524 | { | |
9fd4dcec | 525 | |
49d200de NS |
526 | return __debugfs_create_file(name, mode, parent, data, |
527 | fops ? &debugfs_open_proxy_file_operations : | |
528 | &debugfs_noop_file_operations, | |
529 | fops); | |
1da177e4 | 530 | } |
c6468808 | 531 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 532 | |
e59b4e91 DH |
533 | /** |
534 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
535 | * @name: a pointer to a string containing the name of the file to create. | |
536 | * @mode: the permission that the file should have. | |
537 | * @parent: a pointer to the parent dentry for this file. This should be a | |
538 | * directory dentry if set. If this parameter is NULL, then the | |
539 | * file will be created in the root of the debugfs filesystem. | |
540 | * @data: a pointer to something that the caller will want to get to later | |
541 | * on. The inode.i_private pointer will point to this value on | |
542 | * the open() call. | |
543 | * @fops: a pointer to a struct file_operations that should be used for | |
544 | * this file. | |
545 | * @file_size: initial file size | |
546 | * | |
547 | * This is the basic "create a file" function for debugfs. It allows for a | |
548 | * wide range of flexibility in creating a file, or a directory (if you want | |
549 | * to create a directory, the debugfs_create_dir() function is | |
550 | * recommended to be used instead.) | |
e59b4e91 | 551 | */ |
526ee72d GKH |
552 | void debugfs_create_file_size(const char *name, umode_t mode, |
553 | struct dentry *parent, void *data, | |
554 | const struct file_operations *fops, | |
555 | loff_t file_size) | |
e59b4e91 DH |
556 | { |
557 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
558 | ||
af505cad | 559 | if (!IS_ERR(de)) |
2b0143b5 | 560 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
561 | } |
562 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
563 | ||
1da177e4 LT |
564 | /** |
565 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
566 | * @name: a pointer to a string containing the name of the directory to |
567 | * create. | |
568 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 569 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
570 | * directory will be created in the root of the debugfs filesystem. |
571 | * | |
572 | * This function creates a directory in debugfs with the given name. | |
573 | * | |
574 | * This function will return a pointer to a dentry if it succeeds. This | |
575 | * pointer must be passed to the debugfs_remove() function when the file is | |
576 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 577 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 578 | * returned. |
1da177e4 | 579 | * |
6468b3af | 580 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 581 | * returned. |
8bcbde2b DA |
582 | * |
583 | * NOTE: it's expected that most callers should _ignore_ the errors returned | |
584 | * by this function. Other debugfs functions handle the fact that the "dentry" | |
585 | * passed to them could be an error and they don't crash in that case. | |
586 | * Drivers should generally work fine even if debugfs fails to init anyway. | |
1da177e4 LT |
587 | */ |
588 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
589 | { | |
ad5abd5b | 590 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 591 | struct inode *inode; |
ad5abd5b AV |
592 | |
593 | if (IS_ERR(dentry)) | |
ff9fb72b | 594 | return dentry; |
ad5abd5b | 595 | |
a24c6f7b PE |
596 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
597 | failed_creating(dentry); | |
598 | return ERR_PTR(-EPERM); | |
599 | } | |
600 | ||
edac65ea | 601 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
602 | if (unlikely(!inode)) { |
603 | pr_err("out of free dentries, can not create directory '%s'\n", | |
604 | name); | |
5233e311 | 605 | return failed_creating(dentry); |
43e23b6c | 606 | } |
680b3024 | 607 | |
f5b7769e | 608 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
5496197f | 609 | inode->i_op = &debugfs_dir_inode_operations; |
edac65ea AV |
610 | inode->i_fop = &simple_dir_operations; |
611 | ||
612 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
613 | inc_nlink(inode); | |
680b3024 | 614 | d_instantiate(dentry, inode); |
2b0143b5 DH |
615 | inc_nlink(d_inode(dentry->d_parent)); |
616 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 617 | return end_creating(dentry); |
1da177e4 LT |
618 | } |
619 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
620 | ||
77b3da6e AV |
621 | /** |
622 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
623 | * @name: a pointer to a string containing the name of the file to create. | |
624 | * @parent: a pointer to the parent dentry for this file. This should be a | |
625 | * directory dentry if set. If this parameter is NULL, then the | |
626 | * file will be created in the root of the debugfs filesystem. | |
627 | * @f: function to be called when pathname resolution steps on that one. | |
628 | * @data: opaque argument to pass to f(). | |
629 | * | |
630 | * @f should return what ->d_automount() would. | |
631 | */ | |
632 | struct dentry *debugfs_create_automount(const char *name, | |
633 | struct dentry *parent, | |
93faccbb | 634 | debugfs_automount_t f, |
77b3da6e AV |
635 | void *data) |
636 | { | |
637 | struct dentry *dentry = start_creating(name, parent); | |
638 | struct inode *inode; | |
639 | ||
640 | if (IS_ERR(dentry)) | |
ff9fb72b | 641 | return dentry; |
77b3da6e | 642 | |
a24c6f7b PE |
643 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
644 | failed_creating(dentry); | |
645 | return ERR_PTR(-EPERM); | |
646 | } | |
647 | ||
77b3da6e | 648 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
649 | if (unlikely(!inode)) { |
650 | pr_err("out of free dentries, can not create automount '%s'\n", | |
651 | name); | |
77b3da6e | 652 | return failed_creating(dentry); |
43e23b6c | 653 | } |
77b3da6e | 654 | |
87243deb | 655 | make_empty_dir_inode(inode); |
77b3da6e AV |
656 | inode->i_flags |= S_AUTOMOUNT; |
657 | inode->i_private = data; | |
658 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
659 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
660 | inc_nlink(inode); | |
77b3da6e | 661 | d_instantiate(dentry, inode); |
a8f324a4 RP |
662 | inc_nlink(d_inode(dentry->d_parent)); |
663 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
664 | return end_creating(dentry); |
665 | } | |
666 | EXPORT_SYMBOL(debugfs_create_automount); | |
667 | ||
66f54963 PO |
668 | /** |
669 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
670 | * @name: a pointer to a string containing the name of the symbolic link to | |
671 | * create. | |
672 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 673 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
674 | * then the symbolic link will be created in the root of the debugfs |
675 | * filesystem. | |
676 | * @target: a pointer to a string containing the path to the target of the | |
677 | * symbolic link. | |
678 | * | |
679 | * This function creates a symbolic link with the given name in debugfs that | |
680 | * links to the given target path. | |
681 | * | |
682 | * This function will return a pointer to a dentry if it succeeds. This | |
683 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
684 | * link is to be removed (no automatic cleanup happens if your module is | |
adc92dd4 | 685 | * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR) |
ff9fb72b | 686 | * will be returned. |
66f54963 PO |
687 | * |
688 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 689 | * returned. |
66f54963 PO |
690 | */ |
691 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
692 | const char *target) | |
693 | { | |
ad5abd5b | 694 | struct dentry *dentry; |
680b3024 AV |
695 | struct inode *inode; |
696 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 | 697 | if (!link) |
ff9fb72b | 698 | return ERR_PTR(-ENOMEM); |
66f54963 | 699 | |
ad5abd5b | 700 | dentry = start_creating(name, parent); |
ad5abd5b | 701 | if (IS_ERR(dentry)) { |
66f54963 | 702 | kfree(link); |
ff9fb72b | 703 | return dentry; |
ad5abd5b AV |
704 | } |
705 | ||
edac65ea | 706 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 707 | if (unlikely(!inode)) { |
43e23b6c GKH |
708 | pr_err("out of free dentries, can not create symlink '%s'\n", |
709 | name); | |
ad5abd5b | 710 | kfree(link); |
5233e311 | 711 | return failed_creating(dentry); |
680b3024 | 712 | } |
edac65ea | 713 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5496197f | 714 | inode->i_op = &debugfs_symlink_inode_operations; |
5723cb01 | 715 | inode->i_link = link; |
680b3024 | 716 | d_instantiate(dentry, inode); |
5233e311 | 717 | return end_creating(dentry); |
66f54963 PO |
718 | } |
719 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
720 | ||
823e545c | 721 | static void __debugfs_file_removed(struct dentry *dentry) |
e9117a5a NS |
722 | { |
723 | struct debugfs_fsdata *fsd; | |
724 | ||
7d39bc50 NS |
725 | /* |
726 | * Paired with the closing smp_mb() implied by a successful | |
727 | * cmpxchg() in debugfs_file_get(): either | |
728 | * debugfs_file_get() must see a dead dentry or we must see a | |
729 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
730 | */ | |
731 | smp_mb(); | |
732 | fsd = READ_ONCE(dentry->d_fsdata); | |
733 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
734 | return; | |
e9117a5a NS |
735 | if (!refcount_dec_and_test(&fsd->active_users)) |
736 | wait_for_completion(&fsd->active_users_drained); | |
737 | } | |
738 | ||
a3d1e7eb | 739 | static void remove_one(struct dentry *victim) |
9505e637 | 740 | { |
a3d1e7eb AV |
741 | if (d_is_reg(victim)) |
742 | __debugfs_file_removed(victim); | |
743 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 | 744 | } |
9505e637 HS |
745 | |
746 | /** | |
a3d1e7eb | 747 | * debugfs_remove - recursively removes a directory |
398dc4ad UM |
748 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
749 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
750 | * |
751 | * This function recursively removes a directory tree in debugfs that | |
752 | * was previously created with a call to another debugfs function | |
753 | * (like debugfs_create_file() or variants thereof.) | |
754 | * | |
755 | * This function is required to be called in order for the file to be | |
756 | * removed, no automatic cleanup of files will happen when a module is | |
757 | * removed, you are responsible here. | |
758 | */ | |
a3d1e7eb | 759 | void debugfs_remove(struct dentry *dentry) |
9505e637 | 760 | { |
a59d6293 | 761 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
762 | return; |
763 | ||
a3d1e7eb AV |
764 | simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count); |
765 | simple_recursive_removal(dentry, remove_one); | |
766 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1da177e4 | 767 | } |
a3d1e7eb | 768 | EXPORT_SYMBOL_GPL(debugfs_remove); |
1da177e4 | 769 | |
dec9b2f1 GKH |
770 | /** |
771 | * debugfs_lookup_and_remove - lookup a directory or file and recursively remove it | |
772 | * @name: a pointer to a string containing the name of the item to look up. | |
773 | * @parent: a pointer to the parent dentry of the item. | |
774 | * | |
775 | * This is the equlivant of doing something like | |
776 | * debugfs_remove(debugfs_lookup(..)) but with the proper reference counting | |
777 | * handled for the directory being looked up. | |
778 | */ | |
779 | void debugfs_lookup_and_remove(const char *name, struct dentry *parent) | |
780 | { | |
781 | struct dentry *dentry; | |
782 | ||
783 | dentry = debugfs_lookup(name, parent); | |
784 | if (!dentry) | |
785 | return; | |
786 | ||
787 | debugfs_remove(dentry); | |
788 | dput(dentry); | |
789 | } | |
790 | EXPORT_SYMBOL_GPL(debugfs_lookup_and_remove); | |
791 | ||
cfc94cdf JK |
792 | /** |
793 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
794 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
795 | * should be a directory dentry. | |
796 | * @old_dentry: dentry of an object to be renamed. | |
797 | * @new_dir: a pointer to the parent dentry where the object should be | |
798 | * moved. This should be a directory dentry. | |
799 | * @new_name: a pointer to a string containing the target name. | |
800 | * | |
801 | * This function renames a file/directory in debugfs. The target must not | |
802 | * exist for rename to succeed. | |
803 | * | |
804 | * This function will return a pointer to old_dentry (which is updated to | |
805 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
806 | * returned. | |
807 | * | |
808 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
809 | * returned. | |
810 | */ | |
811 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
812 | struct dentry *new_dir, const char *new_name) | |
813 | { | |
814 | int error; | |
815 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 816 | struct name_snapshot old_name; |
cfc94cdf | 817 | |
d88c93f0 GKH |
818 | if (IS_ERR(old_dir)) |
819 | return old_dir; | |
820 | if (IS_ERR(new_dir)) | |
821 | return new_dir; | |
822 | if (IS_ERR_OR_NULL(old_dentry)) | |
823 | return old_dentry; | |
824 | ||
cfc94cdf JK |
825 | trap = lock_rename(new_dir, old_dir); |
826 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 827 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
828 | goto exit; |
829 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 830 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
831 | d_mountpoint(old_dentry)) |
832 | goto exit; | |
833 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
834 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 835 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
836 | goto exit; |
837 | ||
49d31c2f | 838 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 839 | |
549c7297 CB |
840 | error = simple_rename(&init_user_ns, d_inode(old_dir), old_dentry, |
841 | d_inode(new_dir), dentry, 0); | |
cfc94cdf | 842 | if (error) { |
49d31c2f | 843 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
844 | goto exit; |
845 | } | |
846 | d_move(old_dentry, dentry); | |
f4ec3a3d | 847 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, |
e36cb0b8 | 848 | d_is_dir(old_dentry), |
5a190ae6 | 849 | NULL, old_dentry); |
49d31c2f | 850 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
851 | unlock_rename(new_dir, old_dir); |
852 | dput(dentry); | |
853 | return old_dentry; | |
854 | exit: | |
855 | if (dentry && !IS_ERR(dentry)) | |
856 | dput(dentry); | |
857 | unlock_rename(new_dir, old_dir); | |
ff9fb72b GKH |
858 | if (IS_ERR(dentry)) |
859 | return dentry; | |
860 | return ERR_PTR(-EINVAL); | |
cfc94cdf JK |
861 | } |
862 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
863 | ||
c0f92ba9 FW |
864 | /** |
865 | * debugfs_initialized - Tells whether debugfs has been registered | |
866 | */ | |
867 | bool debugfs_initialized(void) | |
868 | { | |
869 | return debugfs_registered; | |
870 | } | |
871 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
872 | ||
a24c6f7b PE |
873 | static int __init debugfs_kernel(char *str) |
874 | { | |
875 | if (str) { | |
876 | if (!strcmp(str, "on")) | |
877 | debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT; | |
878 | else if (!strcmp(str, "no-mount")) | |
879 | debugfs_allow = DEBUGFS_ALLOW_API; | |
880 | else if (!strcmp(str, "off")) | |
881 | debugfs_allow = 0; | |
882 | } | |
883 | ||
884 | return 0; | |
885 | } | |
886 | early_param("debugfs", debugfs_kernel); | |
1da177e4 LT |
887 | static int __init debugfs_init(void) |
888 | { | |
889 | int retval; | |
890 | ||
a24c6f7b PE |
891 | if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT)) |
892 | return -EPERM; | |
893 | ||
f9bb4882 EB |
894 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
895 | if (retval) | |
896 | return retval; | |
1da177e4 LT |
897 | |
898 | retval = register_filesystem(&debug_fs_type); | |
899 | if (retval) | |
f9bb4882 | 900 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
901 | else |
902 | debugfs_registered = true; | |
903 | ||
1da177e4 LT |
904 | return retval; |
905 | } | |
1da177e4 | 906 | core_initcall(debugfs_init); |