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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; |
1da177e4 | 38 | |
5496197f DH |
39 | /* |
40 | * Don't allow access attributes to be changed whilst the kernel is locked down | |
41 | * so that we can use the file mode as part of a heuristic to determine whether | |
42 | * to lock down individual files. | |
43 | */ | |
44 | static int debugfs_setattr(struct dentry *dentry, struct iattr *ia) | |
45 | { | |
46 | int ret = security_locked_down(LOCKDOWN_DEBUGFS); | |
47 | ||
48 | if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) | |
49 | return ret; | |
50 | return simple_setattr(dentry, ia); | |
51 | } | |
52 | ||
53 | static const struct inode_operations debugfs_file_inode_operations = { | |
54 | .setattr = debugfs_setattr, | |
55 | }; | |
56 | static const struct inode_operations debugfs_dir_inode_operations = { | |
57 | .lookup = simple_lookup, | |
58 | .setattr = debugfs_setattr, | |
59 | }; | |
60 | static const struct inode_operations debugfs_symlink_inode_operations = { | |
61 | .get_link = simple_get_link, | |
62 | .setattr = debugfs_setattr, | |
63 | }; | |
64 | ||
edac65ea | 65 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
66 | { |
67 | struct inode *inode = new_inode(sb); | |
1da177e4 | 68 | if (inode) { |
85fe4025 | 69 | inode->i_ino = get_next_ino(); |
1b48b530 | 70 | inode->i_atime = inode->i_mtime = |
c2050a45 | 71 | inode->i_ctime = current_time(inode); |
1da177e4 | 72 | } |
88e412ea | 73 | return inode; |
1da177e4 LT |
74 | } |
75 | ||
d6e48686 | 76 | struct debugfs_mount_opts { |
7dc05881 EB |
77 | kuid_t uid; |
78 | kgid_t gid; | |
d6e48686 LN |
79 | umode_t mode; |
80 | }; | |
81 | ||
82 | enum { | |
83 | Opt_uid, | |
84 | Opt_gid, | |
85 | Opt_mode, | |
86 | Opt_err | |
87 | }; | |
88 | ||
89 | static const match_table_t tokens = { | |
90 | {Opt_uid, "uid=%u"}, | |
91 | {Opt_gid, "gid=%u"}, | |
92 | {Opt_mode, "mode=%o"}, | |
93 | {Opt_err, NULL} | |
94 | }; | |
95 | ||
96 | struct debugfs_fs_info { | |
97 | struct debugfs_mount_opts mount_opts; | |
98 | }; | |
99 | ||
100 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
101 | { | |
102 | substring_t args[MAX_OPT_ARGS]; | |
103 | int option; | |
104 | int token; | |
7dc05881 EB |
105 | kuid_t uid; |
106 | kgid_t gid; | |
d6e48686 LN |
107 | char *p; |
108 | ||
109 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
110 | ||
111 | while ((p = strsep(&data, ",")) != NULL) { | |
112 | if (!*p) | |
113 | continue; | |
114 | ||
115 | token = match_token(p, tokens, args); | |
116 | switch (token) { | |
117 | case Opt_uid: | |
118 | if (match_int(&args[0], &option)) | |
119 | return -EINVAL; | |
7dc05881 EB |
120 | uid = make_kuid(current_user_ns(), option); |
121 | if (!uid_valid(uid)) | |
122 | return -EINVAL; | |
123 | opts->uid = uid; | |
d6e48686 LN |
124 | break; |
125 | case Opt_gid: | |
f1688e04 | 126 | if (match_int(&args[0], &option)) |
d6e48686 | 127 | return -EINVAL; |
7dc05881 EB |
128 | gid = make_kgid(current_user_ns(), option); |
129 | if (!gid_valid(gid)) | |
130 | return -EINVAL; | |
131 | opts->gid = gid; | |
d6e48686 LN |
132 | break; |
133 | case Opt_mode: | |
134 | if (match_octal(&args[0], &option)) | |
135 | return -EINVAL; | |
136 | opts->mode = option & S_IALLUGO; | |
137 | break; | |
138 | /* | |
139 | * We might like to report bad mount options here; | |
140 | * but traditionally debugfs has ignored all mount options | |
141 | */ | |
142 | } | |
143 | } | |
144 | ||
145 | return 0; | |
146 | } | |
147 | ||
148 | static int debugfs_apply_options(struct super_block *sb) | |
149 | { | |
150 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 151 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
152 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
153 | ||
154 | inode->i_mode &= ~S_IALLUGO; | |
155 | inode->i_mode |= opts->mode; | |
156 | ||
157 | inode->i_uid = opts->uid; | |
158 | inode->i_gid = opts->gid; | |
159 | ||
160 | return 0; | |
161 | } | |
162 | ||
163 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
164 | { | |
165 | int err; | |
166 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
167 | ||
02b9984d | 168 | sync_filesystem(sb); |
d6e48686 LN |
169 | err = debugfs_parse_options(data, &fsi->mount_opts); |
170 | if (err) | |
171 | goto fail; | |
172 | ||
173 | debugfs_apply_options(sb); | |
174 | ||
175 | fail: | |
176 | return err; | |
177 | } | |
178 | ||
179 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
180 | { | |
181 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
182 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
183 | ||
7dc05881 EB |
184 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
185 | seq_printf(m, ",uid=%u", | |
186 | from_kuid_munged(&init_user_ns, opts->uid)); | |
187 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
188 | seq_printf(m, ",gid=%u", | |
189 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
190 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
191 | seq_printf(m, ",mode=%o", opts->mode); | |
192 | ||
193 | return 0; | |
194 | } | |
195 | ||
6234ddf4 | 196 | static void debugfs_free_inode(struct inode *inode) |
0db59e59 | 197 | { |
0db59e59 | 198 | if (S_ISLNK(inode->i_mode)) |
5723cb01 | 199 | kfree(inode->i_link); |
93b919da AV |
200 | free_inode_nonrcu(inode); |
201 | } | |
202 | ||
d6e48686 LN |
203 | static const struct super_operations debugfs_super_operations = { |
204 | .statfs = simple_statfs, | |
205 | .remount_fs = debugfs_remount, | |
206 | .show_options = debugfs_show_options, | |
6234ddf4 | 207 | .free_inode = debugfs_free_inode, |
d6e48686 LN |
208 | }; |
209 | ||
7c8d4698 NS |
210 | static void debugfs_release_dentry(struct dentry *dentry) |
211 | { | |
7d39bc50 NS |
212 | void *fsd = dentry->d_fsdata; |
213 | ||
214 | if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) | |
215 | kfree(dentry->d_fsdata); | |
7c8d4698 NS |
216 | } |
217 | ||
77b3da6e AV |
218 | static struct vfsmount *debugfs_automount(struct path *path) |
219 | { | |
93faccbb EB |
220 | debugfs_automount_t f; |
221 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
222 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
223 | } |
224 | ||
225 | static const struct dentry_operations debugfs_dops = { | |
226 | .d_delete = always_delete_dentry, | |
7c8d4698 | 227 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
228 | .d_automount = debugfs_automount, |
229 | }; | |
230 | ||
1da177e4 LT |
231 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
232 | { | |
cda37124 | 233 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
234 | struct debugfs_fs_info *fsi; |
235 | int err; | |
236 | ||
d6e48686 LN |
237 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
238 | sb->s_fs_info = fsi; | |
239 | if (!fsi) { | |
240 | err = -ENOMEM; | |
241 | goto fail; | |
242 | } | |
243 | ||
244 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
245 | if (err) | |
246 | goto fail; | |
247 | ||
248 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
249 | if (err) | |
250 | goto fail; | |
251 | ||
252 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 253 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
254 | |
255 | debugfs_apply_options(sb); | |
256 | ||
257 | return 0; | |
1da177e4 | 258 | |
d6e48686 LN |
259 | fail: |
260 | kfree(fsi); | |
261 | sb->s_fs_info = NULL; | |
262 | return err; | |
1da177e4 LT |
263 | } |
264 | ||
fc14f2fe | 265 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 266 | int flags, const char *dev_name, |
fc14f2fe | 267 | void *data) |
1da177e4 | 268 | { |
fc14f2fe | 269 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
270 | } |
271 | ||
272 | static struct file_system_type debug_fs_type = { | |
273 | .owner = THIS_MODULE, | |
274 | .name = "debugfs", | |
fc14f2fe | 275 | .mount = debug_mount, |
1da177e4 LT |
276 | .kill_sb = kill_litter_super, |
277 | }; | |
7f78e035 | 278 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 279 | |
a7c5437b OS |
280 | /** |
281 | * debugfs_lookup() - look up an existing debugfs file | |
282 | * @name: a pointer to a string containing the name of the file to look up. | |
283 | * @parent: a pointer to the parent dentry of the file. | |
284 | * | |
285 | * This function will return a pointer to a dentry if it succeeds. If the file | |
286 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
287 | * dentry must be passed to dput() when it is no longer needed. | |
288 | * | |
289 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
290 | * returned. | |
291 | */ | |
292 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
293 | { | |
294 | struct dentry *dentry; | |
295 | ||
296 | if (IS_ERR(parent)) | |
297 | return NULL; | |
298 | ||
299 | if (!parent) | |
300 | parent = debugfs_mount->mnt_root; | |
301 | ||
cd1c0c93 | 302 | dentry = lookup_one_len_unlocked(name, parent, strlen(name)); |
a7c5437b OS |
303 | if (IS_ERR(dentry)) |
304 | return NULL; | |
305 | if (!d_really_is_positive(dentry)) { | |
306 | dput(dentry); | |
307 | return NULL; | |
308 | } | |
309 | return dentry; | |
310 | } | |
311 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
312 | ||
190afd81 | 313 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 314 | { |
190afd81 | 315 | struct dentry *dentry; |
cfa57c11 AV |
316 | int error; |
317 | ||
d03ae477 | 318 | pr_debug("creating file '%s'\n", name); |
cfa57c11 | 319 | |
c9e15f25 GK |
320 | if (IS_ERR(parent)) |
321 | return parent; | |
322 | ||
cfa57c11 AV |
323 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
324 | &debugfs_mount_count); | |
43e23b6c GKH |
325 | if (error) { |
326 | pr_err("Unable to pin filesystem for file '%s'\n", name); | |
190afd81 | 327 | return ERR_PTR(error); |
43e23b6c | 328 | } |
1da177e4 LT |
329 | |
330 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 331 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
332 | * block. A pointer to that is in the struct vfsmount that we |
333 | * have around. | |
334 | */ | |
ef52c75e | 335 | if (!parent) |
4c1d5a64 | 336 | parent = debugfs_mount->mnt_root; |
1da177e4 | 337 | |
5955102c | 338 | inode_lock(d_inode(parent)); |
cfa57c11 | 339 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 340 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
c33d4423 GKH |
341 | if (d_is_dir(dentry)) |
342 | pr_err("Directory '%s' with parent '%s' already present!\n", | |
343 | name, parent->d_name.name); | |
344 | else | |
345 | pr_err("File '%s' in directory '%s' already present!\n", | |
346 | name, parent->d_name.name); | |
cfa57c11 | 347 | dput(dentry); |
190afd81 AV |
348 | dentry = ERR_PTR(-EEXIST); |
349 | } | |
0ee9608c DB |
350 | |
351 | if (IS_ERR(dentry)) { | |
5955102c | 352 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
353 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
354 | } | |
355 | ||
190afd81 AV |
356 | return dentry; |
357 | } | |
358 | ||
5233e311 | 359 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 360 | { |
5955102c | 361 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 362 | dput(dentry); |
5233e311 | 363 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
ff9fb72b | 364 | return ERR_PTR(-ENOMEM); |
5233e311 | 365 | } |
1da177e4 | 366 | |
5233e311 AV |
367 | static struct dentry *end_creating(struct dentry *dentry) |
368 | { | |
5955102c | 369 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
370 | return dentry; |
371 | } | |
372 | ||
49d200de NS |
373 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
374 | struct dentry *parent, void *data, | |
375 | const struct file_operations *proxy_fops, | |
376 | const struct file_operations *real_fops) | |
377 | { | |
378 | struct dentry *dentry; | |
379 | struct inode *inode; | |
380 | ||
381 | if (!(mode & S_IFMT)) | |
382 | mode |= S_IFREG; | |
383 | BUG_ON(!S_ISREG(mode)); | |
384 | dentry = start_creating(name, parent); | |
385 | ||
7d39bc50 | 386 | if (IS_ERR(dentry)) |
ff9fb72b | 387 | return dentry; |
49d200de NS |
388 | |
389 | inode = debugfs_get_inode(dentry->d_sb); | |
43e23b6c GKH |
390 | if (unlikely(!inode)) { |
391 | pr_err("out of free dentries, can not create file '%s'\n", | |
392 | name); | |
49d200de | 393 | return failed_creating(dentry); |
43e23b6c | 394 | } |
49d200de NS |
395 | |
396 | inode->i_mode = mode; | |
397 | inode->i_private = data; | |
398 | ||
5496197f | 399 | inode->i_op = &debugfs_file_inode_operations; |
49d200de | 400 | inode->i_fop = proxy_fops; |
7d39bc50 NS |
401 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
402 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
403 | |
404 | d_instantiate(dentry, inode); | |
405 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
406 | return end_creating(dentry); | |
407 | } | |
408 | ||
1da177e4 LT |
409 | /** |
410 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 411 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 412 | * @mode: the permission that the file should have. |
1da177e4 | 413 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 414 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
415 | * file will be created in the root of the debugfs filesystem. |
416 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 417 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
418 | * the open() call. |
419 | * @fops: a pointer to a struct file_operations that should be used for | |
420 | * this file. | |
421 | * | |
422 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
423 | * wide range of flexibility in creating a file, or a directory (if you want |
424 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
425 | * recommended to be used instead.) |
426 | * | |
427 | * This function will return a pointer to a dentry if it succeeds. This | |
428 | * pointer must be passed to the debugfs_remove() function when the file is | |
429 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
ff9fb72b GKH |
430 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
431 | * returned. | |
1da177e4 | 432 | * |
6468b3af | 433 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 434 | * returned. |
1da177e4 | 435 | */ |
f4ae40a6 | 436 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 437 | struct dentry *parent, void *data, |
99ac48f5 | 438 | const struct file_operations *fops) |
1da177e4 | 439 | { |
680b3024 | 440 | |
49d200de NS |
441 | return __debugfs_create_file(name, mode, parent, data, |
442 | fops ? &debugfs_full_proxy_file_operations : | |
443 | &debugfs_noop_file_operations, | |
444 | fops); | |
445 | } | |
446 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 447 | |
c6468808 NS |
448 | /** |
449 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
450 | * @name: a pointer to a string containing the name of the file to create. | |
451 | * @mode: the permission that the file should have. | |
452 | * @parent: a pointer to the parent dentry for this file. This should be a | |
453 | * directory dentry if set. If this parameter is NULL, then the | |
454 | * file will be created in the root of the debugfs filesystem. | |
455 | * @data: a pointer to something that the caller will want to get to later | |
456 | * on. The inode.i_private pointer will point to this value on | |
457 | * the open() call. | |
458 | * @fops: a pointer to a struct file_operations that should be used for | |
459 | * this file. | |
460 | * | |
461 | * debugfs_create_file_unsafe() is completely analogous to | |
462 | * debugfs_create_file(), the only difference being that the fops | |
463 | * handed it will not get protected against file removals by the | |
464 | * debugfs core. | |
465 | * | |
466 | * It is your responsibility to protect your struct file_operation | |
0eeb2731 SS |
467 | * methods against file removals by means of debugfs_file_get() |
468 | * and debugfs_file_put(). ->open() is still protected by | |
c6468808 NS |
469 | * debugfs though. |
470 | * | |
471 | * Any struct file_operations defined by means of | |
472 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
473 | * thus, may be used here. | |
474 | */ | |
49d200de NS |
475 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
476 | struct dentry *parent, void *data, | |
477 | const struct file_operations *fops) | |
478 | { | |
9fd4dcec | 479 | |
49d200de NS |
480 | return __debugfs_create_file(name, mode, parent, data, |
481 | fops ? &debugfs_open_proxy_file_operations : | |
482 | &debugfs_noop_file_operations, | |
483 | fops); | |
1da177e4 | 484 | } |
c6468808 | 485 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 486 | |
e59b4e91 DH |
487 | /** |
488 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
489 | * @name: a pointer to a string containing the name of the file to create. | |
490 | * @mode: the permission that the file should have. | |
491 | * @parent: a pointer to the parent dentry for this file. This should be a | |
492 | * directory dentry if set. If this parameter is NULL, then the | |
493 | * file will be created in the root of the debugfs filesystem. | |
494 | * @data: a pointer to something that the caller will want to get to later | |
495 | * on. The inode.i_private pointer will point to this value on | |
496 | * the open() call. | |
497 | * @fops: a pointer to a struct file_operations that should be used for | |
498 | * this file. | |
499 | * @file_size: initial file size | |
500 | * | |
501 | * This is the basic "create a file" function for debugfs. It allows for a | |
502 | * wide range of flexibility in creating a file, or a directory (if you want | |
503 | * to create a directory, the debugfs_create_dir() function is | |
504 | * recommended to be used instead.) | |
505 | * | |
506 | * This function will return a pointer to a dentry if it succeeds. This | |
507 | * pointer must be passed to the debugfs_remove() function when the file is | |
508 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
ff9fb72b GKH |
509 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
510 | * returned. | |
e59b4e91 DH |
511 | * |
512 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
513 | * returned. | |
514 | */ | |
515 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
516 | struct dentry *parent, void *data, | |
517 | const struct file_operations *fops, | |
518 | loff_t file_size) | |
519 | { | |
520 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
521 | ||
522 | if (de) | |
2b0143b5 | 523 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
524 | return de; |
525 | } | |
526 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
527 | ||
1da177e4 LT |
528 | /** |
529 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
530 | * @name: a pointer to a string containing the name of the directory to |
531 | * create. | |
532 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 533 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
534 | * directory will be created in the root of the debugfs filesystem. |
535 | * | |
536 | * This function creates a directory in debugfs with the given name. | |
537 | * | |
538 | * This function will return a pointer to a dentry if it succeeds. This | |
539 | * pointer must be passed to the debugfs_remove() function when the file is | |
540 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
ff9fb72b GKH |
541 | * you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) will be |
542 | * returned. | |
1da177e4 | 543 | * |
6468b3af | 544 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 545 | * returned. |
1da177e4 LT |
546 | */ |
547 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
548 | { | |
ad5abd5b | 549 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 550 | struct inode *inode; |
ad5abd5b AV |
551 | |
552 | if (IS_ERR(dentry)) | |
ff9fb72b | 553 | return dentry; |
ad5abd5b | 554 | |
edac65ea | 555 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
556 | if (unlikely(!inode)) { |
557 | pr_err("out of free dentries, can not create directory '%s'\n", | |
558 | name); | |
5233e311 | 559 | return failed_creating(dentry); |
43e23b6c | 560 | } |
680b3024 | 561 | |
f5b7769e | 562 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
5496197f | 563 | inode->i_op = &debugfs_dir_inode_operations; |
edac65ea AV |
564 | inode->i_fop = &simple_dir_operations; |
565 | ||
566 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
567 | inc_nlink(inode); | |
680b3024 | 568 | d_instantiate(dentry, inode); |
2b0143b5 DH |
569 | inc_nlink(d_inode(dentry->d_parent)); |
570 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 571 | return end_creating(dentry); |
1da177e4 LT |
572 | } |
573 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
574 | ||
77b3da6e AV |
575 | /** |
576 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
577 | * @name: a pointer to a string containing the name of the file to create. | |
578 | * @parent: a pointer to the parent dentry for this file. This should be a | |
579 | * directory dentry if set. If this parameter is NULL, then the | |
580 | * file will be created in the root of the debugfs filesystem. | |
581 | * @f: function to be called when pathname resolution steps on that one. | |
582 | * @data: opaque argument to pass to f(). | |
583 | * | |
584 | * @f should return what ->d_automount() would. | |
585 | */ | |
586 | struct dentry *debugfs_create_automount(const char *name, | |
587 | struct dentry *parent, | |
93faccbb | 588 | debugfs_automount_t f, |
77b3da6e AV |
589 | void *data) |
590 | { | |
591 | struct dentry *dentry = start_creating(name, parent); | |
592 | struct inode *inode; | |
593 | ||
594 | if (IS_ERR(dentry)) | |
ff9fb72b | 595 | return dentry; |
77b3da6e AV |
596 | |
597 | inode = debugfs_get_inode(dentry->d_sb); | |
43e23b6c GKH |
598 | if (unlikely(!inode)) { |
599 | pr_err("out of free dentries, can not create automount '%s'\n", | |
600 | name); | |
77b3da6e | 601 | return failed_creating(dentry); |
43e23b6c | 602 | } |
77b3da6e | 603 | |
87243deb | 604 | make_empty_dir_inode(inode); |
77b3da6e AV |
605 | inode->i_flags |= S_AUTOMOUNT; |
606 | inode->i_private = data; | |
607 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
608 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
609 | inc_nlink(inode); | |
77b3da6e | 610 | d_instantiate(dentry, inode); |
a8f324a4 RP |
611 | inc_nlink(d_inode(dentry->d_parent)); |
612 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
613 | return end_creating(dentry); |
614 | } | |
615 | EXPORT_SYMBOL(debugfs_create_automount); | |
616 | ||
66f54963 PO |
617 | /** |
618 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
619 | * @name: a pointer to a string containing the name of the symbolic link to | |
620 | * create. | |
621 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 622 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
623 | * then the symbolic link will be created in the root of the debugfs |
624 | * filesystem. | |
625 | * @target: a pointer to a string containing the path to the target of the | |
626 | * symbolic link. | |
627 | * | |
628 | * This function creates a symbolic link with the given name in debugfs that | |
629 | * links to the given target path. | |
630 | * | |
631 | * This function will return a pointer to a dentry if it succeeds. This | |
632 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
633 | * link is to be removed (no automatic cleanup happens if your module is | |
ff9fb72b GKH |
634 | * unloaded, you are responsible here.) If an error occurs, %ERR_PTR(-ERROR) |
635 | * will be returned. | |
66f54963 PO |
636 | * |
637 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 638 | * returned. |
66f54963 PO |
639 | */ |
640 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
641 | const char *target) | |
642 | { | |
ad5abd5b | 643 | struct dentry *dentry; |
680b3024 AV |
644 | struct inode *inode; |
645 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 | 646 | if (!link) |
ff9fb72b | 647 | return ERR_PTR(-ENOMEM); |
66f54963 | 648 | |
ad5abd5b | 649 | dentry = start_creating(name, parent); |
ad5abd5b | 650 | if (IS_ERR(dentry)) { |
66f54963 | 651 | kfree(link); |
ff9fb72b | 652 | return dentry; |
ad5abd5b AV |
653 | } |
654 | ||
edac65ea | 655 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 656 | if (unlikely(!inode)) { |
43e23b6c GKH |
657 | pr_err("out of free dentries, can not create symlink '%s'\n", |
658 | name); | |
ad5abd5b | 659 | kfree(link); |
5233e311 | 660 | return failed_creating(dentry); |
680b3024 | 661 | } |
edac65ea | 662 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5496197f | 663 | inode->i_op = &debugfs_symlink_inode_operations; |
5723cb01 | 664 | inode->i_link = link; |
680b3024 | 665 | d_instantiate(dentry, inode); |
5233e311 | 666 | return end_creating(dentry); |
66f54963 PO |
667 | } |
668 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
669 | ||
823e545c | 670 | static void __debugfs_file_removed(struct dentry *dentry) |
e9117a5a NS |
671 | { |
672 | struct debugfs_fsdata *fsd; | |
673 | ||
7d39bc50 NS |
674 | /* |
675 | * Paired with the closing smp_mb() implied by a successful | |
676 | * cmpxchg() in debugfs_file_get(): either | |
677 | * debugfs_file_get() must see a dead dentry or we must see a | |
678 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
679 | */ | |
680 | smp_mb(); | |
681 | fsd = READ_ONCE(dentry->d_fsdata); | |
682 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
683 | return; | |
e9117a5a NS |
684 | if (!refcount_dec_and_test(&fsd->active_users)) |
685 | wait_for_completion(&fsd->active_users_drained); | |
686 | } | |
687 | ||
25d41d84 | 688 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
689 | { |
690 | int ret = 0; | |
691 | ||
dc3f4198 | 692 | if (simple_positive(dentry)) { |
0db59e59 | 693 | dget(dentry); |
823e545c AG |
694 | if (d_is_dir(dentry)) { |
695 | ret = simple_rmdir(d_inode(parent), dentry); | |
6679ea6d AG |
696 | if (!ret) |
697 | fsnotify_rmdir(d_inode(parent), dentry); | |
e9117a5a | 698 | } else { |
823e545c | 699 | simple_unlink(d_inode(parent), dentry); |
6679ea6d | 700 | fsnotify_unlink(d_inode(parent), dentry); |
e9117a5a | 701 | } |
823e545c AG |
702 | if (!ret) |
703 | d_delete(dentry); | |
704 | if (d_is_reg(dentry)) | |
705 | __debugfs_file_removed(dentry); | |
0db59e59 | 706 | dput(dentry); |
9505e637 | 707 | } |
25d41d84 | 708 | return ret; |
9505e637 HS |
709 | } |
710 | ||
1da177e4 LT |
711 | /** |
712 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 | 713 | * @dentry: a pointer to a the dentry of the file or directory to be |
398dc4ad UM |
714 | * removed. If this parameter is NULL or an error value, nothing |
715 | * will be done. | |
1da177e4 LT |
716 | * |
717 | * This function removes a file or directory in debugfs that was previously | |
718 | * created with a call to another debugfs function (like | |
5a65980e | 719 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
720 | * |
721 | * This function is required to be called in order for the file to be | |
722 | * removed, no automatic cleanup of files will happen when a module is | |
723 | * removed, you are responsible here. | |
724 | */ | |
725 | void debugfs_remove(struct dentry *dentry) | |
726 | { | |
727 | struct dentry *parent; | |
25d41d84 JK |
728 | int ret; |
729 | ||
a59d6293 | 730 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
731 | return; |
732 | ||
733 | parent = dentry->d_parent; | |
5955102c | 734 | inode_lock(d_inode(parent)); |
25d41d84 | 735 | ret = __debugfs_remove(dentry, parent); |
5955102c | 736 | inode_unlock(d_inode(parent)); |
25d41d84 JK |
737 | if (!ret) |
738 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
739 | } |
740 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
741 | ||
742 | /** | |
743 | * debugfs_remove_recursive - recursively removes a directory | |
398dc4ad UM |
744 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
745 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
746 | * |
747 | * This function recursively removes a directory tree in debugfs that | |
748 | * was previously created with a call to another debugfs function | |
749 | * (like debugfs_create_file() or variants thereof.) | |
750 | * | |
751 | * This function is required to be called in order for the file to be | |
752 | * removed, no automatic cleanup of files will happen when a module is | |
753 | * removed, you are responsible here. | |
754 | */ | |
755 | void debugfs_remove_recursive(struct dentry *dentry) | |
756 | { | |
485d4402 | 757 | struct dentry *child, *parent; |
9505e637 | 758 | |
a59d6293 | 759 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
760 | return; |
761 | ||
9505e637 | 762 | parent = dentry; |
776164c1 | 763 | down: |
5955102c | 764 | inode_lock(d_inode(parent)); |
485d4402 SR |
765 | loop: |
766 | /* | |
767 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
768 | * lock, the child can be unlinked and set to be freed which can | |
769 | * use the d_u.d_child as the rcu head and corrupt this list. | |
770 | */ | |
771 | spin_lock(&parent->d_lock); | |
946e51f2 | 772 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 773 | if (!simple_positive(child)) |
776164c1 | 774 | continue; |
9505e637 | 775 | |
776164c1 | 776 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 777 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 778 | spin_unlock(&parent->d_lock); |
5955102c | 779 | inode_unlock(d_inode(parent)); |
9505e637 | 780 | parent = child; |
776164c1 | 781 | goto down; |
1da177e4 | 782 | } |
485d4402 SR |
783 | |
784 | spin_unlock(&parent->d_lock); | |
785 | ||
776164c1 ON |
786 | if (!__debugfs_remove(child, parent)) |
787 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
788 | |
789 | /* | |
790 | * The parent->d_lock protects agaist child from unlinking | |
791 | * from d_subdirs. When releasing the parent->d_lock we can | |
792 | * no longer trust that the next pointer is valid. | |
793 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 794 | * simple_positive() check. |
485d4402 SR |
795 | */ |
796 | goto loop; | |
1da177e4 | 797 | } |
485d4402 | 798 | spin_unlock(&parent->d_lock); |
9505e637 | 799 | |
5955102c | 800 | inode_unlock(d_inode(parent)); |
776164c1 ON |
801 | child = parent; |
802 | parent = parent->d_parent; | |
5955102c | 803 | inode_lock(d_inode(parent)); |
776164c1 | 804 | |
485d4402 SR |
805 | if (child != dentry) |
806 | /* go up */ | |
807 | goto loop; | |
776164c1 ON |
808 | |
809 | if (!__debugfs_remove(child, parent)) | |
810 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
5955102c | 811 | inode_unlock(d_inode(parent)); |
1da177e4 | 812 | } |
9505e637 | 813 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 814 | |
cfc94cdf JK |
815 | /** |
816 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
817 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
818 | * should be a directory dentry. | |
819 | * @old_dentry: dentry of an object to be renamed. | |
820 | * @new_dir: a pointer to the parent dentry where the object should be | |
821 | * moved. This should be a directory dentry. | |
822 | * @new_name: a pointer to a string containing the target name. | |
823 | * | |
824 | * This function renames a file/directory in debugfs. The target must not | |
825 | * exist for rename to succeed. | |
826 | * | |
827 | * This function will return a pointer to old_dentry (which is updated to | |
828 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
829 | * returned. | |
830 | * | |
831 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
832 | * returned. | |
833 | */ | |
834 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
835 | struct dentry *new_dir, const char *new_name) | |
836 | { | |
837 | int error; | |
838 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 839 | struct name_snapshot old_name; |
cfc94cdf | 840 | |
d88c93f0 GKH |
841 | if (IS_ERR(old_dir)) |
842 | return old_dir; | |
843 | if (IS_ERR(new_dir)) | |
844 | return new_dir; | |
845 | if (IS_ERR_OR_NULL(old_dentry)) | |
846 | return old_dentry; | |
847 | ||
cfc94cdf JK |
848 | trap = lock_rename(new_dir, old_dir); |
849 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 850 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
851 | goto exit; |
852 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 853 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
854 | d_mountpoint(old_dentry)) |
855 | goto exit; | |
856 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
857 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 858 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
859 | goto exit; |
860 | ||
49d31c2f | 861 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 862 | |
2b0143b5 | 863 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
e0e0be8a | 864 | dentry, 0); |
cfc94cdf | 865 | if (error) { |
49d31c2f | 866 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
867 | goto exit; |
868 | } | |
869 | d_move(old_dentry, dentry); | |
f4ec3a3d | 870 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, |
e36cb0b8 | 871 | d_is_dir(old_dentry), |
5a190ae6 | 872 | NULL, old_dentry); |
49d31c2f | 873 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
874 | unlock_rename(new_dir, old_dir); |
875 | dput(dentry); | |
876 | return old_dentry; | |
877 | exit: | |
878 | if (dentry && !IS_ERR(dentry)) | |
879 | dput(dentry); | |
880 | unlock_rename(new_dir, old_dir); | |
ff9fb72b GKH |
881 | if (IS_ERR(dentry)) |
882 | return dentry; | |
883 | return ERR_PTR(-EINVAL); | |
cfc94cdf JK |
884 | } |
885 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
886 | ||
c0f92ba9 FW |
887 | /** |
888 | * debugfs_initialized - Tells whether debugfs has been registered | |
889 | */ | |
890 | bool debugfs_initialized(void) | |
891 | { | |
892 | return debugfs_registered; | |
893 | } | |
894 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
895 | ||
1da177e4 LT |
896 | static int __init debugfs_init(void) |
897 | { | |
898 | int retval; | |
899 | ||
f9bb4882 EB |
900 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
901 | if (retval) | |
902 | return retval; | |
1da177e4 LT |
903 | |
904 | retval = register_filesystem(&debug_fs_type); | |
905 | if (retval) | |
f9bb4882 | 906 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
907 | else |
908 | debugfs_registered = true; | |
909 | ||
1da177e4 LT |
910 | return retval; |
911 | } | |
1da177e4 | 912 | core_initcall(debugfs_init); |
1da177e4 | 913 |