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 DH |
47 | { |
48 | int ret = security_locked_down(LOCKDOWN_DEBUGFS); | |
49 | ||
50 | if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID))) | |
51 | return ret; | |
549c7297 | 52 | return simple_setattr(&init_user_ns, dentry, ia); |
5496197f DH |
53 | } |
54 | ||
55 | static const struct inode_operations debugfs_file_inode_operations = { | |
56 | .setattr = debugfs_setattr, | |
57 | }; | |
58 | static const struct inode_operations debugfs_dir_inode_operations = { | |
59 | .lookup = simple_lookup, | |
60 | .setattr = debugfs_setattr, | |
61 | }; | |
62 | static const struct inode_operations debugfs_symlink_inode_operations = { | |
63 | .get_link = simple_get_link, | |
64 | .setattr = debugfs_setattr, | |
65 | }; | |
66 | ||
edac65ea | 67 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
68 | { |
69 | struct inode *inode = new_inode(sb); | |
1da177e4 | 70 | if (inode) { |
85fe4025 | 71 | inode->i_ino = get_next_ino(); |
1b48b530 | 72 | inode->i_atime = inode->i_mtime = |
c2050a45 | 73 | inode->i_ctime = current_time(inode); |
1da177e4 | 74 | } |
88e412ea | 75 | return inode; |
1da177e4 LT |
76 | } |
77 | ||
d6e48686 | 78 | struct debugfs_mount_opts { |
7dc05881 EB |
79 | kuid_t uid; |
80 | kgid_t gid; | |
d6e48686 LN |
81 | umode_t mode; |
82 | }; | |
83 | ||
84 | enum { | |
85 | Opt_uid, | |
86 | Opt_gid, | |
87 | Opt_mode, | |
88 | Opt_err | |
89 | }; | |
90 | ||
91 | static const match_table_t tokens = { | |
92 | {Opt_uid, "uid=%u"}, | |
93 | {Opt_gid, "gid=%u"}, | |
94 | {Opt_mode, "mode=%o"}, | |
95 | {Opt_err, NULL} | |
96 | }; | |
97 | ||
98 | struct debugfs_fs_info { | |
99 | struct debugfs_mount_opts mount_opts; | |
100 | }; | |
101 | ||
102 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
103 | { | |
104 | substring_t args[MAX_OPT_ARGS]; | |
105 | int option; | |
106 | int token; | |
7dc05881 EB |
107 | kuid_t uid; |
108 | kgid_t gid; | |
d6e48686 LN |
109 | char *p; |
110 | ||
111 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
112 | ||
113 | while ((p = strsep(&data, ",")) != NULL) { | |
114 | if (!*p) | |
115 | continue; | |
116 | ||
117 | token = match_token(p, tokens, args); | |
118 | switch (token) { | |
119 | case Opt_uid: | |
120 | if (match_int(&args[0], &option)) | |
121 | return -EINVAL; | |
7dc05881 EB |
122 | uid = make_kuid(current_user_ns(), option); |
123 | if (!uid_valid(uid)) | |
124 | return -EINVAL; | |
125 | opts->uid = uid; | |
d6e48686 LN |
126 | break; |
127 | case Opt_gid: | |
f1688e04 | 128 | if (match_int(&args[0], &option)) |
d6e48686 | 129 | return -EINVAL; |
7dc05881 EB |
130 | gid = make_kgid(current_user_ns(), option); |
131 | if (!gid_valid(gid)) | |
132 | return -EINVAL; | |
133 | opts->gid = gid; | |
d6e48686 LN |
134 | break; |
135 | case Opt_mode: | |
136 | if (match_octal(&args[0], &option)) | |
137 | return -EINVAL; | |
138 | opts->mode = option & S_IALLUGO; | |
139 | break; | |
140 | /* | |
141 | * We might like to report bad mount options here; | |
142 | * but traditionally debugfs has ignored all mount options | |
143 | */ | |
144 | } | |
145 | } | |
146 | ||
147 | return 0; | |
148 | } | |
149 | ||
150 | static int debugfs_apply_options(struct super_block *sb) | |
151 | { | |
152 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 153 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
154 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
155 | ||
156 | inode->i_mode &= ~S_IALLUGO; | |
157 | inode->i_mode |= opts->mode; | |
158 | ||
159 | inode->i_uid = opts->uid; | |
160 | inode->i_gid = opts->gid; | |
161 | ||
162 | return 0; | |
163 | } | |
164 | ||
165 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
166 | { | |
167 | int err; | |
168 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
169 | ||
02b9984d | 170 | sync_filesystem(sb); |
d6e48686 LN |
171 | err = debugfs_parse_options(data, &fsi->mount_opts); |
172 | if (err) | |
173 | goto fail; | |
174 | ||
175 | debugfs_apply_options(sb); | |
176 | ||
177 | fail: | |
178 | return err; | |
179 | } | |
180 | ||
181 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
182 | { | |
183 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
184 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
185 | ||
7dc05881 EB |
186 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
187 | seq_printf(m, ",uid=%u", | |
188 | from_kuid_munged(&init_user_ns, opts->uid)); | |
189 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
190 | seq_printf(m, ",gid=%u", | |
191 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
192 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
193 | seq_printf(m, ",mode=%o", opts->mode); | |
194 | ||
195 | return 0; | |
196 | } | |
197 | ||
6234ddf4 | 198 | static void debugfs_free_inode(struct inode *inode) |
0db59e59 | 199 | { |
0db59e59 | 200 | if (S_ISLNK(inode->i_mode)) |
5723cb01 | 201 | kfree(inode->i_link); |
93b919da AV |
202 | free_inode_nonrcu(inode); |
203 | } | |
204 | ||
d6e48686 LN |
205 | static const struct super_operations debugfs_super_operations = { |
206 | .statfs = simple_statfs, | |
207 | .remount_fs = debugfs_remount, | |
208 | .show_options = debugfs_show_options, | |
6234ddf4 | 209 | .free_inode = debugfs_free_inode, |
d6e48686 LN |
210 | }; |
211 | ||
7c8d4698 NS |
212 | static void debugfs_release_dentry(struct dentry *dentry) |
213 | { | |
7d39bc50 NS |
214 | void *fsd = dentry->d_fsdata; |
215 | ||
216 | if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)) | |
217 | kfree(dentry->d_fsdata); | |
7c8d4698 NS |
218 | } |
219 | ||
77b3da6e AV |
220 | static struct vfsmount *debugfs_automount(struct path *path) |
221 | { | |
93faccbb EB |
222 | debugfs_automount_t f; |
223 | f = (debugfs_automount_t)path->dentry->d_fsdata; | |
224 | return f(path->dentry, d_inode(path->dentry)->i_private); | |
77b3da6e AV |
225 | } |
226 | ||
227 | static const struct dentry_operations debugfs_dops = { | |
228 | .d_delete = always_delete_dentry, | |
7c8d4698 | 229 | .d_release = debugfs_release_dentry, |
77b3da6e AV |
230 | .d_automount = debugfs_automount, |
231 | }; | |
232 | ||
1da177e4 LT |
233 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
234 | { | |
cda37124 | 235 | static const struct tree_descr debug_files[] = {{""}}; |
d6e48686 LN |
236 | struct debugfs_fs_info *fsi; |
237 | int err; | |
238 | ||
d6e48686 LN |
239 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); |
240 | sb->s_fs_info = fsi; | |
241 | if (!fsi) { | |
242 | err = -ENOMEM; | |
243 | goto fail; | |
244 | } | |
245 | ||
246 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
247 | if (err) | |
248 | goto fail; | |
249 | ||
250 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
251 | if (err) | |
252 | goto fail; | |
253 | ||
254 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 255 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
256 | |
257 | debugfs_apply_options(sb); | |
258 | ||
259 | return 0; | |
1da177e4 | 260 | |
d6e48686 LN |
261 | fail: |
262 | kfree(fsi); | |
263 | sb->s_fs_info = NULL; | |
264 | return err; | |
1da177e4 LT |
265 | } |
266 | ||
fc14f2fe | 267 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 268 | int flags, const char *dev_name, |
fc14f2fe | 269 | void *data) |
1da177e4 | 270 | { |
a24c6f7b PE |
271 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
272 | return ERR_PTR(-EPERM); | |
273 | ||
fc14f2fe | 274 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
275 | } |
276 | ||
277 | static struct file_system_type debug_fs_type = { | |
278 | .owner = THIS_MODULE, | |
279 | .name = "debugfs", | |
fc14f2fe | 280 | .mount = debug_mount, |
1da177e4 LT |
281 | .kill_sb = kill_litter_super, |
282 | }; | |
7f78e035 | 283 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 284 | |
a7c5437b OS |
285 | /** |
286 | * debugfs_lookup() - look up an existing debugfs file | |
287 | * @name: a pointer to a string containing the name of the file to look up. | |
288 | * @parent: a pointer to the parent dentry of the file. | |
289 | * | |
290 | * This function will return a pointer to a dentry if it succeeds. If the file | |
291 | * doesn't exist or an error occurs, %NULL will be returned. The returned | |
292 | * dentry must be passed to dput() when it is no longer needed. | |
293 | * | |
294 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
295 | * returned. | |
296 | */ | |
297 | struct dentry *debugfs_lookup(const char *name, struct dentry *parent) | |
298 | { | |
299 | struct dentry *dentry; | |
300 | ||
bc6de804 | 301 | if (!debugfs_initialized() || IS_ERR_OR_NULL(name) || IS_ERR(parent)) |
a7c5437b OS |
302 | return NULL; |
303 | ||
304 | if (!parent) | |
305 | parent = debugfs_mount->mnt_root; | |
306 | ||
6c2d4798 | 307 | dentry = lookup_positive_unlocked(name, parent, strlen(name)); |
a7c5437b OS |
308 | if (IS_ERR(dentry)) |
309 | return NULL; | |
a7c5437b OS |
310 | return dentry; |
311 | } | |
312 | EXPORT_SYMBOL_GPL(debugfs_lookup); | |
313 | ||
190afd81 | 314 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 315 | { |
190afd81 | 316 | struct dentry *dentry; |
cfa57c11 AV |
317 | int error; |
318 | ||
a24c6f7b PE |
319 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) |
320 | return ERR_PTR(-EPERM); | |
321 | ||
56348560 GKH |
322 | if (!debugfs_initialized()) |
323 | return ERR_PTR(-ENOENT); | |
324 | ||
d03ae477 | 325 | pr_debug("creating file '%s'\n", name); |
cfa57c11 | 326 | |
c9e15f25 GK |
327 | if (IS_ERR(parent)) |
328 | return parent; | |
329 | ||
cfa57c11 AV |
330 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
331 | &debugfs_mount_count); | |
43e23b6c GKH |
332 | if (error) { |
333 | pr_err("Unable to pin filesystem for file '%s'\n", name); | |
190afd81 | 334 | return ERR_PTR(error); |
43e23b6c | 335 | } |
1da177e4 LT |
336 | |
337 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 338 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
339 | * block. A pointer to that is in the struct vfsmount that we |
340 | * have around. | |
341 | */ | |
ef52c75e | 342 | if (!parent) |
4c1d5a64 | 343 | parent = debugfs_mount->mnt_root; |
1da177e4 | 344 | |
5955102c | 345 | inode_lock(d_inode(parent)); |
a3d1e7eb AV |
346 | if (unlikely(IS_DEADDIR(d_inode(parent)))) |
347 | dentry = ERR_PTR(-ENOENT); | |
348 | else | |
349 | dentry = lookup_one_len(name, parent, strlen(name)); | |
2b0143b5 | 350 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
c33d4423 GKH |
351 | if (d_is_dir(dentry)) |
352 | pr_err("Directory '%s' with parent '%s' already present!\n", | |
353 | name, parent->d_name.name); | |
354 | else | |
355 | pr_err("File '%s' in directory '%s' already present!\n", | |
356 | name, parent->d_name.name); | |
cfa57c11 | 357 | dput(dentry); |
190afd81 AV |
358 | dentry = ERR_PTR(-EEXIST); |
359 | } | |
0ee9608c DB |
360 | |
361 | if (IS_ERR(dentry)) { | |
5955102c | 362 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
363 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
364 | } | |
365 | ||
190afd81 AV |
366 | return dentry; |
367 | } | |
368 | ||
5233e311 | 369 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 370 | { |
5955102c | 371 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 372 | dput(dentry); |
5233e311 | 373 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
ff9fb72b | 374 | return ERR_PTR(-ENOMEM); |
5233e311 | 375 | } |
1da177e4 | 376 | |
5233e311 AV |
377 | static struct dentry *end_creating(struct dentry *dentry) |
378 | { | |
5955102c | 379 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
380 | return dentry; |
381 | } | |
382 | ||
49d200de NS |
383 | static struct dentry *__debugfs_create_file(const char *name, umode_t mode, |
384 | struct dentry *parent, void *data, | |
385 | const struct file_operations *proxy_fops, | |
386 | const struct file_operations *real_fops) | |
387 | { | |
388 | struct dentry *dentry; | |
389 | struct inode *inode; | |
390 | ||
391 | if (!(mode & S_IFMT)) | |
392 | mode |= S_IFREG; | |
393 | BUG_ON(!S_ISREG(mode)); | |
394 | dentry = start_creating(name, parent); | |
395 | ||
7d39bc50 | 396 | if (IS_ERR(dentry)) |
ff9fb72b | 397 | return dentry; |
49d200de | 398 | |
a24c6f7b PE |
399 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
400 | failed_creating(dentry); | |
401 | return ERR_PTR(-EPERM); | |
402 | } | |
403 | ||
49d200de | 404 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
405 | if (unlikely(!inode)) { |
406 | pr_err("out of free dentries, can not create file '%s'\n", | |
407 | name); | |
49d200de | 408 | return failed_creating(dentry); |
43e23b6c | 409 | } |
49d200de NS |
410 | |
411 | inode->i_mode = mode; | |
412 | inode->i_private = data; | |
413 | ||
5496197f | 414 | inode->i_op = &debugfs_file_inode_operations; |
49d200de | 415 | inode->i_fop = proxy_fops; |
7d39bc50 NS |
416 | dentry->d_fsdata = (void *)((unsigned long)real_fops | |
417 | DEBUGFS_FSDATA_IS_REAL_FOPS_BIT); | |
49d200de NS |
418 | |
419 | d_instantiate(dentry, inode); | |
420 | fsnotify_create(d_inode(dentry->d_parent), dentry); | |
421 | return end_creating(dentry); | |
422 | } | |
423 | ||
1da177e4 LT |
424 | /** |
425 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 426 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 427 | * @mode: the permission that the file should have. |
1da177e4 | 428 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 429 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
430 | * file will be created in the root of the debugfs filesystem. |
431 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 432 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
433 | * the open() call. |
434 | * @fops: a pointer to a struct file_operations that should be used for | |
435 | * this file. | |
436 | * | |
437 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
438 | * wide range of flexibility in creating a file, or a directory (if you want |
439 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
440 | * recommended to be used instead.) |
441 | * | |
442 | * This function will return a pointer to a dentry if it succeeds. This | |
443 | * pointer must be passed to the debugfs_remove() function when the file is | |
444 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 445 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 446 | * returned. |
1da177e4 | 447 | * |
6468b3af | 448 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 449 | * returned. |
1da177e4 | 450 | */ |
f4ae40a6 | 451 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 452 | struct dentry *parent, void *data, |
99ac48f5 | 453 | const struct file_operations *fops) |
1da177e4 | 454 | { |
680b3024 | 455 | |
49d200de NS |
456 | return __debugfs_create_file(name, mode, parent, data, |
457 | fops ? &debugfs_full_proxy_file_operations : | |
458 | &debugfs_noop_file_operations, | |
459 | fops); | |
460 | } | |
461 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
9fd4dcec | 462 | |
c6468808 NS |
463 | /** |
464 | * debugfs_create_file_unsafe - create a file in the debugfs filesystem | |
465 | * @name: a pointer to a string containing the name of the file to create. | |
466 | * @mode: the permission that the file should have. | |
467 | * @parent: a pointer to the parent dentry for this file. This should be a | |
468 | * directory dentry if set. If this parameter is NULL, then the | |
469 | * file will be created in the root of the debugfs filesystem. | |
470 | * @data: a pointer to something that the caller will want to get to later | |
471 | * on. The inode.i_private pointer will point to this value on | |
472 | * the open() call. | |
473 | * @fops: a pointer to a struct file_operations that should be used for | |
474 | * this file. | |
475 | * | |
476 | * debugfs_create_file_unsafe() is completely analogous to | |
477 | * debugfs_create_file(), the only difference being that the fops | |
478 | * handed it will not get protected against file removals by the | |
479 | * debugfs core. | |
480 | * | |
481 | * It is your responsibility to protect your struct file_operation | |
0eeb2731 SS |
482 | * methods against file removals by means of debugfs_file_get() |
483 | * and debugfs_file_put(). ->open() is still protected by | |
c6468808 NS |
484 | * debugfs though. |
485 | * | |
486 | * Any struct file_operations defined by means of | |
487 | * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and | |
488 | * thus, may be used here. | |
489 | */ | |
49d200de NS |
490 | struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode, |
491 | struct dentry *parent, void *data, | |
492 | const struct file_operations *fops) | |
493 | { | |
9fd4dcec | 494 | |
49d200de NS |
495 | return __debugfs_create_file(name, mode, parent, data, |
496 | fops ? &debugfs_open_proxy_file_operations : | |
497 | &debugfs_noop_file_operations, | |
498 | fops); | |
1da177e4 | 499 | } |
c6468808 | 500 | EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe); |
1da177e4 | 501 | |
e59b4e91 DH |
502 | /** |
503 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
504 | * @name: a pointer to a string containing the name of the file to create. | |
505 | * @mode: the permission that the file should have. | |
506 | * @parent: a pointer to the parent dentry for this file. This should be a | |
507 | * directory dentry if set. If this parameter is NULL, then the | |
508 | * file will be created in the root of the debugfs filesystem. | |
509 | * @data: a pointer to something that the caller will want to get to later | |
510 | * on. The inode.i_private pointer will point to this value on | |
511 | * the open() call. | |
512 | * @fops: a pointer to a struct file_operations that should be used for | |
513 | * this file. | |
514 | * @file_size: initial file size | |
515 | * | |
516 | * This is the basic "create a file" function for debugfs. It allows for a | |
517 | * wide range of flexibility in creating a file, or a directory (if you want | |
518 | * to create a directory, the debugfs_create_dir() function is | |
519 | * recommended to be used instead.) | |
e59b4e91 | 520 | */ |
526ee72d GKH |
521 | void debugfs_create_file_size(const char *name, umode_t mode, |
522 | struct dentry *parent, void *data, | |
523 | const struct file_operations *fops, | |
524 | loff_t file_size) | |
e59b4e91 DH |
525 | { |
526 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
527 | ||
528 | if (de) | |
2b0143b5 | 529 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
530 | } |
531 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
532 | ||
1da177e4 LT |
533 | /** |
534 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
535 | * @name: a pointer to a string containing the name of the directory to |
536 | * create. | |
537 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 538 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
539 | * directory will be created in the root of the debugfs filesystem. |
540 | * | |
541 | * This function creates a directory in debugfs with the given name. | |
542 | * | |
543 | * This function will return a pointer to a dentry if it succeeds. This | |
544 | * pointer must be passed to the debugfs_remove() function when the file is | |
545 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
adc92dd4 | 546 | * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be |
ff9fb72b | 547 | * returned. |
1da177e4 | 548 | * |
6468b3af | 549 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 550 | * returned. |
1da177e4 LT |
551 | */ |
552 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
553 | { | |
ad5abd5b | 554 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 555 | struct inode *inode; |
ad5abd5b AV |
556 | |
557 | if (IS_ERR(dentry)) | |
ff9fb72b | 558 | return dentry; |
ad5abd5b | 559 | |
a24c6f7b PE |
560 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
561 | failed_creating(dentry); | |
562 | return ERR_PTR(-EPERM); | |
563 | } | |
564 | ||
edac65ea | 565 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
566 | if (unlikely(!inode)) { |
567 | pr_err("out of free dentries, can not create directory '%s'\n", | |
568 | name); | |
5233e311 | 569 | return failed_creating(dentry); |
43e23b6c | 570 | } |
680b3024 | 571 | |
f5b7769e | 572 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
5496197f | 573 | inode->i_op = &debugfs_dir_inode_operations; |
edac65ea AV |
574 | inode->i_fop = &simple_dir_operations; |
575 | ||
576 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
577 | inc_nlink(inode); | |
680b3024 | 578 | d_instantiate(dentry, inode); |
2b0143b5 DH |
579 | inc_nlink(d_inode(dentry->d_parent)); |
580 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 581 | return end_creating(dentry); |
1da177e4 LT |
582 | } |
583 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
584 | ||
77b3da6e AV |
585 | /** |
586 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
587 | * @name: a pointer to a string containing the name of the file to create. | |
588 | * @parent: a pointer to the parent dentry for this file. This should be a | |
589 | * directory dentry if set. If this parameter is NULL, then the | |
590 | * file will be created in the root of the debugfs filesystem. | |
591 | * @f: function to be called when pathname resolution steps on that one. | |
592 | * @data: opaque argument to pass to f(). | |
593 | * | |
594 | * @f should return what ->d_automount() would. | |
595 | */ | |
596 | struct dentry *debugfs_create_automount(const char *name, | |
597 | struct dentry *parent, | |
93faccbb | 598 | debugfs_automount_t f, |
77b3da6e AV |
599 | void *data) |
600 | { | |
601 | struct dentry *dentry = start_creating(name, parent); | |
602 | struct inode *inode; | |
603 | ||
604 | if (IS_ERR(dentry)) | |
ff9fb72b | 605 | return dentry; |
77b3da6e | 606 | |
a24c6f7b PE |
607 | if (!(debugfs_allow & DEBUGFS_ALLOW_API)) { |
608 | failed_creating(dentry); | |
609 | return ERR_PTR(-EPERM); | |
610 | } | |
611 | ||
77b3da6e | 612 | inode = debugfs_get_inode(dentry->d_sb); |
43e23b6c GKH |
613 | if (unlikely(!inode)) { |
614 | pr_err("out of free dentries, can not create automount '%s'\n", | |
615 | name); | |
77b3da6e | 616 | return failed_creating(dentry); |
43e23b6c | 617 | } |
77b3da6e | 618 | |
87243deb | 619 | make_empty_dir_inode(inode); |
77b3da6e AV |
620 | inode->i_flags |= S_AUTOMOUNT; |
621 | inode->i_private = data; | |
622 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
623 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
624 | inc_nlink(inode); | |
77b3da6e | 625 | d_instantiate(dentry, inode); |
a8f324a4 RP |
626 | inc_nlink(d_inode(dentry->d_parent)); |
627 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
628 | return end_creating(dentry); |
629 | } | |
630 | EXPORT_SYMBOL(debugfs_create_automount); | |
631 | ||
66f54963 PO |
632 | /** |
633 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
634 | * @name: a pointer to a string containing the name of the symbolic link to | |
635 | * create. | |
636 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 637 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
638 | * then the symbolic link will be created in the root of the debugfs |
639 | * filesystem. | |
640 | * @target: a pointer to a string containing the path to the target of the | |
641 | * symbolic link. | |
642 | * | |
643 | * This function creates a symbolic link with the given name in debugfs that | |
644 | * links to the given target path. | |
645 | * | |
646 | * This function will return a pointer to a dentry if it succeeds. This | |
647 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
648 | * link is to be removed (no automatic cleanup happens if your module is | |
adc92dd4 | 649 | * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR) |
ff9fb72b | 650 | * will be returned. |
66f54963 PO |
651 | * |
652 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 653 | * returned. |
66f54963 PO |
654 | */ |
655 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
656 | const char *target) | |
657 | { | |
ad5abd5b | 658 | struct dentry *dentry; |
680b3024 AV |
659 | struct inode *inode; |
660 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 | 661 | if (!link) |
ff9fb72b | 662 | return ERR_PTR(-ENOMEM); |
66f54963 | 663 | |
ad5abd5b | 664 | dentry = start_creating(name, parent); |
ad5abd5b | 665 | if (IS_ERR(dentry)) { |
66f54963 | 666 | kfree(link); |
ff9fb72b | 667 | return dentry; |
ad5abd5b AV |
668 | } |
669 | ||
edac65ea | 670 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 671 | if (unlikely(!inode)) { |
43e23b6c GKH |
672 | pr_err("out of free dentries, can not create symlink '%s'\n", |
673 | name); | |
ad5abd5b | 674 | kfree(link); |
5233e311 | 675 | return failed_creating(dentry); |
680b3024 | 676 | } |
edac65ea | 677 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5496197f | 678 | inode->i_op = &debugfs_symlink_inode_operations; |
5723cb01 | 679 | inode->i_link = link; |
680b3024 | 680 | d_instantiate(dentry, inode); |
5233e311 | 681 | return end_creating(dentry); |
66f54963 PO |
682 | } |
683 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
684 | ||
823e545c | 685 | static void __debugfs_file_removed(struct dentry *dentry) |
e9117a5a NS |
686 | { |
687 | struct debugfs_fsdata *fsd; | |
688 | ||
7d39bc50 NS |
689 | /* |
690 | * Paired with the closing smp_mb() implied by a successful | |
691 | * cmpxchg() in debugfs_file_get(): either | |
692 | * debugfs_file_get() must see a dead dentry or we must see a | |
693 | * debugfs_fsdata instance at ->d_fsdata here (or both). | |
694 | */ | |
695 | smp_mb(); | |
696 | fsd = READ_ONCE(dentry->d_fsdata); | |
697 | if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT) | |
698 | return; | |
e9117a5a NS |
699 | if (!refcount_dec_and_test(&fsd->active_users)) |
700 | wait_for_completion(&fsd->active_users_drained); | |
701 | } | |
702 | ||
a3d1e7eb | 703 | static void remove_one(struct dentry *victim) |
9505e637 | 704 | { |
a3d1e7eb AV |
705 | if (d_is_reg(victim)) |
706 | __debugfs_file_removed(victim); | |
707 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 | 708 | } |
9505e637 HS |
709 | |
710 | /** | |
a3d1e7eb | 711 | * debugfs_remove - recursively removes a directory |
398dc4ad UM |
712 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
713 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
714 | * |
715 | * This function recursively removes a directory tree in debugfs that | |
716 | * was previously created with a call to another debugfs function | |
717 | * (like debugfs_create_file() or variants thereof.) | |
718 | * | |
719 | * This function is required to be called in order for the file to be | |
720 | * removed, no automatic cleanup of files will happen when a module is | |
721 | * removed, you are responsible here. | |
722 | */ | |
a3d1e7eb | 723 | void debugfs_remove(struct dentry *dentry) |
9505e637 | 724 | { |
a59d6293 | 725 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
726 | return; |
727 | ||
a3d1e7eb AV |
728 | simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count); |
729 | simple_recursive_removal(dentry, remove_one); | |
730 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
1da177e4 | 731 | } |
a3d1e7eb | 732 | EXPORT_SYMBOL_GPL(debugfs_remove); |
1da177e4 | 733 | |
cfc94cdf JK |
734 | /** |
735 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
736 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
737 | * should be a directory dentry. | |
738 | * @old_dentry: dentry of an object to be renamed. | |
739 | * @new_dir: a pointer to the parent dentry where the object should be | |
740 | * moved. This should be a directory dentry. | |
741 | * @new_name: a pointer to a string containing the target name. | |
742 | * | |
743 | * This function renames a file/directory in debugfs. The target must not | |
744 | * exist for rename to succeed. | |
745 | * | |
746 | * This function will return a pointer to old_dentry (which is updated to | |
747 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
748 | * returned. | |
749 | * | |
750 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
751 | * returned. | |
752 | */ | |
753 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
754 | struct dentry *new_dir, const char *new_name) | |
755 | { | |
756 | int error; | |
757 | struct dentry *dentry = NULL, *trap; | |
49d31c2f | 758 | struct name_snapshot old_name; |
cfc94cdf | 759 | |
d88c93f0 GKH |
760 | if (IS_ERR(old_dir)) |
761 | return old_dir; | |
762 | if (IS_ERR(new_dir)) | |
763 | return new_dir; | |
764 | if (IS_ERR_OR_NULL(old_dentry)) | |
765 | return old_dentry; | |
766 | ||
cfc94cdf JK |
767 | trap = lock_rename(new_dir, old_dir); |
768 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 769 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
770 | goto exit; |
771 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 772 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
773 | d_mountpoint(old_dentry)) |
774 | goto exit; | |
775 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
776 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 777 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
778 | goto exit; |
779 | ||
49d31c2f | 780 | take_dentry_name_snapshot(&old_name, old_dentry); |
cfc94cdf | 781 | |
549c7297 CB |
782 | error = simple_rename(&init_user_ns, d_inode(old_dir), old_dentry, |
783 | d_inode(new_dir), dentry, 0); | |
cfc94cdf | 784 | if (error) { |
49d31c2f | 785 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
786 | goto exit; |
787 | } | |
788 | d_move(old_dentry, dentry); | |
f4ec3a3d | 789 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name, |
e36cb0b8 | 790 | d_is_dir(old_dentry), |
5a190ae6 | 791 | NULL, old_dentry); |
49d31c2f | 792 | release_dentry_name_snapshot(&old_name); |
cfc94cdf JK |
793 | unlock_rename(new_dir, old_dir); |
794 | dput(dentry); | |
795 | return old_dentry; | |
796 | exit: | |
797 | if (dentry && !IS_ERR(dentry)) | |
798 | dput(dentry); | |
799 | unlock_rename(new_dir, old_dir); | |
ff9fb72b GKH |
800 | if (IS_ERR(dentry)) |
801 | return dentry; | |
802 | return ERR_PTR(-EINVAL); | |
cfc94cdf JK |
803 | } |
804 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
805 | ||
c0f92ba9 FW |
806 | /** |
807 | * debugfs_initialized - Tells whether debugfs has been registered | |
808 | */ | |
809 | bool debugfs_initialized(void) | |
810 | { | |
811 | return debugfs_registered; | |
812 | } | |
813 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
814 | ||
a24c6f7b PE |
815 | static int __init debugfs_kernel(char *str) |
816 | { | |
817 | if (str) { | |
818 | if (!strcmp(str, "on")) | |
819 | debugfs_allow = DEBUGFS_ALLOW_API | DEBUGFS_ALLOW_MOUNT; | |
820 | else if (!strcmp(str, "no-mount")) | |
821 | debugfs_allow = DEBUGFS_ALLOW_API; | |
822 | else if (!strcmp(str, "off")) | |
823 | debugfs_allow = 0; | |
824 | } | |
825 | ||
826 | return 0; | |
827 | } | |
828 | early_param("debugfs", debugfs_kernel); | |
1da177e4 LT |
829 | static int __init debugfs_init(void) |
830 | { | |
831 | int retval; | |
832 | ||
a24c6f7b PE |
833 | if (!(debugfs_allow & DEBUGFS_ALLOW_MOUNT)) |
834 | return -EPERM; | |
835 | ||
f9bb4882 EB |
836 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
837 | if (retval) | |
838 | return retval; | |
1da177e4 LT |
839 | |
840 | retval = register_filesystem(&debug_fs_type); | |
841 | if (retval) | |
f9bb4882 | 842 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
843 | else |
844 | debugfs_registered = true; | |
845 | ||
1da177e4 LT |
846 | return retval; |
847 | } | |
1da177e4 | 848 | core_initcall(debugfs_init); |