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