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1 : : // SPDX-License-Identifier: GPL-2.0
2 : : /*
3 : : * inode.c - part of debugfs, a tiny little debug file system
4 : : *
5 : : * Copyright (C) 2004,2019 Greg Kroah-Hartman <greg@kroah.com>
6 : : * Copyright (C) 2004 IBM Inc.
7 : : * Copyright (C) 2019 Linux Foundation <gregkh@linuxfoundation.org>
8 : : *
9 : : * debugfs is for people to use instead of /proc or /sys.
10 : : * See ./Documentation/core-api/kernel-api.rst for more details.
11 : : */
12 : :
13 : : #define pr_fmt(fmt) "debugfs: " fmt
14 : :
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>
20 : : #include <linux/kobject.h>
21 : : #include <linux/namei.h>
22 : : #include <linux/debugfs.h>
23 : : #include <linux/fsnotify.h>
24 : : #include <linux/string.h>
25 : : #include <linux/seq_file.h>
26 : : #include <linux/parser.h>
27 : : #include <linux/magic.h>
28 : : #include <linux/slab.h>
29 : : #include <linux/security.h>
30 : :
31 : : #include "internal.h"
32 : :
33 : : #define DEBUGFS_DEFAULT_MODE 0700
34 : :
35 : : static struct vfsmount *debugfs_mount;
36 : : static int debugfs_mount_count;
37 : : static bool debugfs_registered;
38 : :
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 : 0 : static int debugfs_setattr(struct dentry *dentry, struct iattr *ia)
45 : : {
46 : 0 : int ret = security_locked_down(LOCKDOWN_DEBUGFS);
47 : :
48 [ # # # # ]: 0 : if (ret && (ia->ia_valid & (ATTR_MODE | ATTR_UID | ATTR_GID)))
49 : : return ret;
50 : 0 : 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 : :
65 : 122493 : static struct inode *debugfs_get_inode(struct super_block *sb)
66 : : {
67 : 122493 : struct inode *inode = new_inode(sb);
68 [ + - ]: 122493 : if (inode) {
69 : 122493 : inode->i_ino = get_next_ino();
70 : 122493 : inode->i_atime = inode->i_mtime =
71 : 122493 : inode->i_ctime = current_time(inode);
72 : : }
73 : 122493 : return inode;
74 : : }
75 : :
76 : : struct debugfs_mount_opts {
77 : : kuid_t uid;
78 : : kgid_t gid;
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 : 42 : static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
101 : : {
102 : 42 : substring_t args[MAX_OPT_ARGS];
103 : 42 : int option;
104 : 42 : int token;
105 : 42 : kuid_t uid;
106 : 42 : kgid_t gid;
107 : 42 : char *p;
108 : :
109 : 42 : opts->mode = DEBUGFS_DEFAULT_MODE;
110 : :
111 [ - + ]: 42 : while ((p = strsep(&data, ",")) != NULL) {
112 [ # # ]: 0 : if (!*p)
113 : 0 : continue;
114 : :
115 : 0 : token = match_token(p, tokens, args);
116 [ # # # # ]: 0 : switch (token) {
117 : 0 : case Opt_uid:
118 [ # # ]: 0 : if (match_int(&args[0], &option))
119 : : return -EINVAL;
120 [ # # ]: 0 : uid = make_kuid(current_user_ns(), option);
121 [ # # ]: 0 : if (!uid_valid(uid))
122 : : return -EINVAL;
123 : 0 : opts->uid = uid;
124 : 0 : break;
125 : 0 : case Opt_gid:
126 [ # # ]: 0 : if (match_int(&args[0], &option))
127 : : return -EINVAL;
128 [ # # ]: 0 : gid = make_kgid(current_user_ns(), option);
129 [ # # ]: 0 : if (!gid_valid(gid))
130 : : return -EINVAL;
131 : 0 : opts->gid = gid;
132 : 0 : break;
133 : 0 : case Opt_mode:
134 [ # # ]: 0 : if (match_octal(&args[0], &option))
135 : : return -EINVAL;
136 : 0 : opts->mode = option & S_IALLUGO;
137 : 0 : 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 : 42 : static int debugfs_apply_options(struct super_block *sb)
149 : : {
150 : 42 : struct debugfs_fs_info *fsi = sb->s_fs_info;
151 : 42 : struct inode *inode = d_inode(sb->s_root);
152 : 42 : struct debugfs_mount_opts *opts = &fsi->mount_opts;
153 : :
154 : 42 : inode->i_mode &= ~S_IALLUGO;
155 : 42 : inode->i_mode |= opts->mode;
156 : :
157 : 42 : inode->i_uid = opts->uid;
158 : 42 : inode->i_gid = opts->gid;
159 : :
160 : 21 : return 0;
161 : : }
162 : :
163 : 21 : static int debugfs_remount(struct super_block *sb, int *flags, char *data)
164 : : {
165 : 21 : int err;
166 : 21 : struct debugfs_fs_info *fsi = sb->s_fs_info;
167 : :
168 : 21 : sync_filesystem(sb);
169 : 21 : err = debugfs_parse_options(data, &fsi->mount_opts);
170 [ - + ]: 21 : if (err)
171 : 0 : goto fail;
172 : :
173 : 21 : debugfs_apply_options(sb);
174 : :
175 : 21 : fail:
176 : 21 : return err;
177 : : }
178 : :
179 : 2292 : static int debugfs_show_options(struct seq_file *m, struct dentry *root)
180 : : {
181 : 2292 : struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
182 : 2292 : struct debugfs_mount_opts *opts = &fsi->mount_opts;
183 : :
184 [ - + ]: 2292 : if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
185 [ # # ]: 0 : seq_printf(m, ",uid=%u",
186 : : from_kuid_munged(&init_user_ns, opts->uid));
187 [ - + ]: 2292 : if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
188 [ # # ]: 0 : seq_printf(m, ",gid=%u",
189 : : from_kgid_munged(&init_user_ns, opts->gid));
190 [ - + ]: 2292 : if (opts->mode != DEBUGFS_DEFAULT_MODE)
191 : 0 : seq_printf(m, ",mode=%o", opts->mode);
192 : :
193 : 2292 : return 0;
194 : : }
195 : :
196 : 0 : static void debugfs_free_inode(struct inode *inode)
197 : : {
198 [ # # ]: 0 : if (S_ISLNK(inode->i_mode))
199 : 0 : kfree(inode->i_link);
200 : 0 : free_inode_nonrcu(inode);
201 : 0 : }
202 : :
203 : : static const struct super_operations debugfs_super_operations = {
204 : : .statfs = simple_statfs,
205 : : .remount_fs = debugfs_remount,
206 : : .show_options = debugfs_show_options,
207 : : .free_inode = debugfs_free_inode,
208 : : };
209 : :
210 : 6111 : static void debugfs_release_dentry(struct dentry *dentry)
211 : : {
212 : 6111 : void *fsd = dentry->d_fsdata;
213 : :
214 [ + - ]: 6111 : if (!((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT))
215 : 6111 : kfree(dentry->d_fsdata);
216 : 6111 : }
217 : :
218 : 0 : static struct vfsmount *debugfs_automount(struct path *path)
219 : : {
220 : 0 : debugfs_automount_t f;
221 : 0 : f = (debugfs_automount_t)path->dentry->d_fsdata;
222 : 0 : return f(path->dentry, d_inode(path->dentry)->i_private);
223 : : }
224 : :
225 : : static const struct dentry_operations debugfs_dops = {
226 : : .d_delete = always_delete_dentry,
227 : : .d_release = debugfs_release_dentry,
228 : : .d_automount = debugfs_automount,
229 : : };
230 : :
231 : 21 : static int debug_fill_super(struct super_block *sb, void *data, int silent)
232 : : {
233 : 21 : static const struct tree_descr debug_files[] = {{""}};
234 : 21 : struct debugfs_fs_info *fsi;
235 : 21 : int err;
236 : :
237 : 21 : fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
238 : 21 : sb->s_fs_info = fsi;
239 [ - + ]: 21 : if (!fsi) {
240 : 0 : err = -ENOMEM;
241 : 0 : goto fail;
242 : : }
243 : :
244 : 21 : err = debugfs_parse_options(data, &fsi->mount_opts);
245 [ - + ]: 21 : if (err)
246 : 0 : goto fail;
247 : :
248 : 21 : err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
249 [ - + ]: 21 : if (err)
250 : 0 : goto fail;
251 : :
252 : 21 : sb->s_op = &debugfs_super_operations;
253 : 21 : sb->s_d_op = &debugfs_dops;
254 : :
255 : 21 : debugfs_apply_options(sb);
256 : :
257 : 21 : return 0;
258 : :
259 : 0 : fail:
260 : 0 : kfree(fsi);
261 : 0 : sb->s_fs_info = NULL;
262 : 0 : return err;
263 : : }
264 : :
265 : 42 : static struct dentry *debug_mount(struct file_system_type *fs_type,
266 : : int flags, const char *dev_name,
267 : : void *data)
268 : : {
269 : 42 : return mount_single(fs_type, flags, data, debug_fill_super);
270 : : }
271 : :
272 : : static struct file_system_type debug_fs_type = {
273 : : .owner = THIS_MODULE,
274 : : .name = "debugfs",
275 : : .mount = debug_mount,
276 : : .kill_sb = kill_litter_super,
277 : : };
278 : : MODULE_ALIAS_FS("debugfs");
279 : :
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 : 0 : struct dentry *debugfs_lookup(const char *name, struct dentry *parent)
293 : : {
294 : 0 : struct dentry *dentry;
295 : :
296 [ # # ]: 0 : if (IS_ERR(parent))
297 : : return NULL;
298 : :
299 [ # # ]: 0 : if (!parent)
300 : 0 : parent = debugfs_mount->mnt_root;
301 : :
302 : 0 : dentry = lookup_positive_unlocked(name, parent, strlen(name));
303 [ # # ]: 0 : if (IS_ERR(dentry))
304 : 0 : return NULL;
305 : : return dentry;
306 : : }
307 : : EXPORT_SYMBOL_GPL(debugfs_lookup);
308 : :
309 : 122493 : static struct dentry *start_creating(const char *name, struct dentry *parent)
310 : : {
311 : 122493 : struct dentry *dentry;
312 : 122493 : int error;
313 : :
314 : 122493 : pr_debug("creating file '%s'\n", name);
315 : :
316 [ + - ]: 122493 : if (IS_ERR(parent))
317 : : return parent;
318 : :
319 : 122493 : error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
320 : : &debugfs_mount_count);
321 [ - + ]: 122493 : if (error) {
322 : 0 : pr_err("Unable to pin filesystem for file '%s'\n", name);
323 : 0 : return ERR_PTR(error);
324 : : }
325 : :
326 : : /* If the parent is not specified, we create it in the root.
327 : : * We need the root dentry to do this, which is in the super
328 : : * block. A pointer to that is in the struct vfsmount that we
329 : : * have around.
330 : : */
331 [ + + ]: 122493 : if (!parent)
332 : 693 : parent = debugfs_mount->mnt_root;
333 : :
334 : 122493 : inode_lock(d_inode(parent));
335 [ + - ]: 122493 : if (unlikely(IS_DEADDIR(d_inode(parent))))
336 : : dentry = ERR_PTR(-ENOENT);
337 : : else
338 : 122493 : dentry = lookup_one_len(name, parent, strlen(name));
339 [ + - - + ]: 122493 : if (!IS_ERR(dentry) && d_really_is_positive(dentry)) {
340 [ # # # # ]: 0 : if (d_is_dir(dentry))
341 : 0 : pr_err("Directory '%s' with parent '%s' already present!\n",
342 : : name, parent->d_name.name);
343 : : else
344 : 0 : pr_err("File '%s' in directory '%s' already present!\n",
345 : : name, parent->d_name.name);
346 : 0 : dput(dentry);
347 : 0 : dentry = ERR_PTR(-EEXIST);
348 : : }
349 : :
350 [ - + ]: 122493 : if (IS_ERR(dentry)) {
351 : 0 : inode_unlock(d_inode(parent));
352 : 0 : simple_release_fs(&debugfs_mount, &debugfs_mount_count);
353 : : }
354 : :
355 : : return dentry;
356 : : }
357 : :
358 : 0 : static struct dentry *failed_creating(struct dentry *dentry)
359 : : {
360 : 0 : inode_unlock(d_inode(dentry->d_parent));
361 : 0 : dput(dentry);
362 : 0 : simple_release_fs(&debugfs_mount, &debugfs_mount_count);
363 : 0 : return ERR_PTR(-ENOMEM);
364 : : }
365 : :
366 : 122493 : static struct dentry *end_creating(struct dentry *dentry)
367 : : {
368 : 122493 : inode_unlock(d_inode(dentry->d_parent));
369 : 122493 : return dentry;
370 : : }
371 : :
372 : 62475 : static struct dentry *__debugfs_create_file(const char *name, umode_t mode,
373 : : struct dentry *parent, void *data,
374 : : const struct file_operations *proxy_fops,
375 : : const struct file_operations *real_fops)
376 : : {
377 : 62475 : struct dentry *dentry;
378 : 62475 : struct inode *inode;
379 : :
380 [ + + ]: 62475 : if (!(mode & S_IFMT))
381 : 62454 : mode |= S_IFREG;
382 [ - + ]: 62475 : BUG_ON(!S_ISREG(mode));
383 : 62475 : dentry = start_creating(name, parent);
384 : :
385 [ + - ]: 62475 : if (IS_ERR(dentry))
386 : : return dentry;
387 : :
388 : 62475 : inode = debugfs_get_inode(dentry->d_sb);
389 [ - + ]: 62475 : if (unlikely(!inode)) {
390 : 0 : pr_err("out of free dentries, can not create file '%s'\n",
391 : : name);
392 : 0 : return failed_creating(dentry);
393 : : }
394 : :
395 : 62475 : inode->i_mode = mode;
396 : 62475 : inode->i_private = data;
397 : :
398 : 62475 : inode->i_op = &debugfs_file_inode_operations;
399 : 62475 : inode->i_fop = proxy_fops;
400 : 62475 : dentry->d_fsdata = (void *)((unsigned long)real_fops |
401 : : DEBUGFS_FSDATA_IS_REAL_FOPS_BIT);
402 : :
403 : 62475 : d_instantiate(dentry, inode);
404 : 62475 : fsnotify_create(d_inode(dentry->d_parent), dentry);
405 : 62475 : return end_creating(dentry);
406 : : }
407 : :
408 : : /**
409 : : * debugfs_create_file - create a file in the debugfs filesystem
410 : : * @name: a pointer to a string containing the name of the file to create.
411 : : * @mode: the permission that the file should have.
412 : : * @parent: a pointer to the parent dentry for this file. This should be a
413 : : * directory dentry if set. If this parameter is NULL, then the
414 : : * file will be created in the root of the debugfs filesystem.
415 : : * @data: a pointer to something that the caller will want to get to later
416 : : * on. The inode.i_private pointer will point to this value on
417 : : * the open() call.
418 : : * @fops: a pointer to a struct file_operations that should be used for
419 : : * this file.
420 : : *
421 : : * This is the basic "create a file" function for debugfs. It allows for a
422 : : * wide range of flexibility in creating a file, or a directory (if you want
423 : : * to create a directory, the debugfs_create_dir() function is
424 : : * recommended to be used instead.)
425 : : *
426 : : * This function will return a pointer to a dentry if it succeeds. This
427 : : * pointer must be passed to the debugfs_remove() function when the file is
428 : : * to be removed (no automatic cleanup happens if your module is unloaded,
429 : : * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
430 : : * returned.
431 : : *
432 : : * If debugfs is not enabled in the kernel, the value -%ENODEV will be
433 : : * returned.
434 : : */
435 : 62139 : struct dentry *debugfs_create_file(const char *name, umode_t mode,
436 : : struct dentry *parent, void *data,
437 : : const struct file_operations *fops)
438 : : {
439 : :
440 [ - + ]: 62139 : return __debugfs_create_file(name, mode, parent, data,
441 : : fops ? &debugfs_full_proxy_file_operations :
442 : : &debugfs_noop_file_operations,
443 : : fops);
444 : : }
445 : : EXPORT_SYMBOL_GPL(debugfs_create_file);
446 : :
447 : : /**
448 : : * debugfs_create_file_unsafe - create a file in the debugfs filesystem
449 : : * @name: a pointer to a string containing the name of the file to create.
450 : : * @mode: the permission that the file should have.
451 : : * @parent: a pointer to the parent dentry for this file. This should be a
452 : : * directory dentry if set. If this parameter is NULL, then the
453 : : * file will be created in the root of the debugfs filesystem.
454 : : * @data: a pointer to something that the caller will want to get to later
455 : : * on. The inode.i_private pointer will point to this value on
456 : : * the open() call.
457 : : * @fops: a pointer to a struct file_operations that should be used for
458 : : * this file.
459 : : *
460 : : * debugfs_create_file_unsafe() is completely analogous to
461 : : * debugfs_create_file(), the only difference being that the fops
462 : : * handed it will not get protected against file removals by the
463 : : * debugfs core.
464 : : *
465 : : * It is your responsibility to protect your struct file_operation
466 : : * methods against file removals by means of debugfs_file_get()
467 : : * and debugfs_file_put(). ->open() is still protected by
468 : : * debugfs though.
469 : : *
470 : : * Any struct file_operations defined by means of
471 : : * DEFINE_DEBUGFS_ATTRIBUTE() is protected against file removals and
472 : : * thus, may be used here.
473 : : */
474 : 336 : struct dentry *debugfs_create_file_unsafe(const char *name, umode_t mode,
475 : : struct dentry *parent, void *data,
476 : : const struct file_operations *fops)
477 : : {
478 : :
479 [ - + ]: 336 : return __debugfs_create_file(name, mode, parent, data,
480 : : fops ? &debugfs_open_proxy_file_operations :
481 : : &debugfs_noop_file_operations,
482 : : fops);
483 : : }
484 : : EXPORT_SYMBOL_GPL(debugfs_create_file_unsafe);
485 : :
486 : : /**
487 : : * debugfs_create_file_size - create a file in the debugfs filesystem
488 : : * @name: a pointer to a string containing the name of the file to create.
489 : : * @mode: the permission that the file should have.
490 : : * @parent: a pointer to the parent dentry for this file. This should be a
491 : : * directory dentry if set. If this parameter is NULL, then the
492 : : * file will be created in the root of the debugfs filesystem.
493 : : * @data: a pointer to something that the caller will want to get to later
494 : : * on. The inode.i_private pointer will point to this value on
495 : : * the open() call.
496 : : * @fops: a pointer to a struct file_operations that should be used for
497 : : * this file.
498 : : * @file_size: initial file size
499 : : *
500 : : * This is the basic "create a file" function for debugfs. It allows for a
501 : : * wide range of flexibility in creating a file, or a directory (if you want
502 : : * to create a directory, the debugfs_create_dir() function is
503 : : * recommended to be used instead.)
504 : : *
505 : : * This function will return a pointer to a dentry if it succeeds. This
506 : : * pointer must be passed to the debugfs_remove() function when the file is
507 : : * to be removed (no automatic cleanup happens if your module is unloaded,
508 : : * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
509 : : * returned.
510 : : *
511 : : * If debugfs is not enabled in the kernel, the value -%ENODEV will be
512 : : * returned.
513 : : */
514 : 0 : struct dentry *debugfs_create_file_size(const char *name, umode_t mode,
515 : : struct dentry *parent, void *data,
516 : : const struct file_operations *fops,
517 : : loff_t file_size)
518 : : {
519 [ # # ]: 0 : struct dentry *de = debugfs_create_file(name, mode, parent, data, fops);
520 : :
521 [ # # ]: 0 : if (de)
522 : 0 : d_inode(de)->i_size = file_size;
523 : 0 : return de;
524 : : }
525 : : EXPORT_SYMBOL_GPL(debugfs_create_file_size);
526 : :
527 : : /**
528 : : * debugfs_create_dir - create a directory in the debugfs filesystem
529 : : * @name: a pointer to a string containing the name of the directory to
530 : : * create.
531 : : * @parent: a pointer to the parent dentry for this file. This should be a
532 : : * directory dentry if set. If this parameter is NULL, then the
533 : : * directory will be created in the root of the debugfs filesystem.
534 : : *
535 : : * This function creates a directory in debugfs with the given name.
536 : : *
537 : : * This function will return a pointer to a dentry if it succeeds. This
538 : : * pointer must be passed to the debugfs_remove() function when the file is
539 : : * to be removed (no automatic cleanup happens if your module is unloaded,
540 : : * you are responsible here.) If an error occurs, ERR_PTR(-ERROR) will be
541 : : * returned.
542 : : *
543 : : * If debugfs is not enabled in the kernel, the value -%ENODEV will be
544 : : * returned.
545 : : */
546 : 6804 : struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
547 : : {
548 : 6804 : struct dentry *dentry = start_creating(name, parent);
549 : 6804 : struct inode *inode;
550 : :
551 [ + - ]: 6804 : if (IS_ERR(dentry))
552 : : return dentry;
553 : :
554 : 6804 : inode = debugfs_get_inode(dentry->d_sb);
555 [ - + ]: 6804 : if (unlikely(!inode)) {
556 : 0 : pr_err("out of free dentries, can not create directory '%s'\n",
557 : : name);
558 : 0 : return failed_creating(dentry);
559 : : }
560 : :
561 : 6804 : inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO;
562 : 6804 : inode->i_op = &debugfs_dir_inode_operations;
563 : 6804 : inode->i_fop = &simple_dir_operations;
564 : :
565 : : /* directory inodes start off with i_nlink == 2 (for "." entry) */
566 : 6804 : inc_nlink(inode);
567 : 6804 : d_instantiate(dentry, inode);
568 : 6804 : inc_nlink(d_inode(dentry->d_parent));
569 : 6804 : fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
570 : 6804 : return end_creating(dentry);
571 : : }
572 : : EXPORT_SYMBOL_GPL(debugfs_create_dir);
573 : :
574 : : /**
575 : : * debugfs_create_automount - create automount point in the debugfs filesystem
576 : : * @name: a pointer to a string containing the name of the file to create.
577 : : * @parent: a pointer to the parent dentry for this file. This should be a
578 : : * directory dentry if set. If this parameter is NULL, then the
579 : : * file will be created in the root of the debugfs filesystem.
580 : : * @f: function to be called when pathname resolution steps on that one.
581 : : * @data: opaque argument to pass to f().
582 : : *
583 : : * @f should return what ->d_automount() would.
584 : : */
585 : 21 : struct dentry *debugfs_create_automount(const char *name,
586 : : struct dentry *parent,
587 : : debugfs_automount_t f,
588 : : void *data)
589 : : {
590 : 21 : struct dentry *dentry = start_creating(name, parent);
591 : 21 : struct inode *inode;
592 : :
593 [ + - ]: 21 : if (IS_ERR(dentry))
594 : : return dentry;
595 : :
596 : 21 : inode = debugfs_get_inode(dentry->d_sb);
597 [ - + ]: 21 : if (unlikely(!inode)) {
598 : 0 : pr_err("out of free dentries, can not create automount '%s'\n",
599 : : name);
600 : 0 : return failed_creating(dentry);
601 : : }
602 : :
603 : 21 : make_empty_dir_inode(inode);
604 : 21 : inode->i_flags |= S_AUTOMOUNT;
605 : 21 : inode->i_private = data;
606 : 21 : dentry->d_fsdata = (void *)f;
607 : : /* directory inodes start off with i_nlink == 2 (for "." entry) */
608 : 21 : inc_nlink(inode);
609 : 21 : d_instantiate(dentry, inode);
610 : 21 : inc_nlink(d_inode(dentry->d_parent));
611 : 21 : fsnotify_mkdir(d_inode(dentry->d_parent), dentry);
612 : 21 : return end_creating(dentry);
613 : : }
614 : : EXPORT_SYMBOL(debugfs_create_automount);
615 : :
616 : : /**
617 : : * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
618 : : * @name: a pointer to a string containing the name of the symbolic link to
619 : : * create.
620 : : * @parent: a pointer to the parent dentry for this symbolic link. This
621 : : * should be a directory dentry if set. If this parameter is NULL,
622 : : * then the symbolic link will be created in the root of the debugfs
623 : : * filesystem.
624 : : * @target: a pointer to a string containing the path to the target of the
625 : : * symbolic link.
626 : : *
627 : : * This function creates a symbolic link with the given name in debugfs that
628 : : * links to the given target path.
629 : : *
630 : : * This function will return a pointer to a dentry if it succeeds. This
631 : : * pointer must be passed to the debugfs_remove() function when the symbolic
632 : : * link is to be removed (no automatic cleanup happens if your module is
633 : : * unloaded, you are responsible here.) If an error occurs, ERR_PTR(-ERROR)
634 : : * will be returned.
635 : : *
636 : : * If debugfs is not enabled in the kernel, the value -%ENODEV will be
637 : : * returned.
638 : : */
639 : 53193 : struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
640 : : const char *target)
641 : : {
642 : 53193 : struct dentry *dentry;
643 : 53193 : struct inode *inode;
644 : 53193 : char *link = kstrdup(target, GFP_KERNEL);
645 [ + - ]: 53193 : if (!link)
646 : : return ERR_PTR(-ENOMEM);
647 : :
648 : 53193 : dentry = start_creating(name, parent);
649 [ - + ]: 53193 : if (IS_ERR(dentry)) {
650 : 0 : kfree(link);
651 : 0 : return dentry;
652 : : }
653 : :
654 : 53193 : inode = debugfs_get_inode(dentry->d_sb);
655 [ - + ]: 53193 : if (unlikely(!inode)) {
656 : 0 : pr_err("out of free dentries, can not create symlink '%s'\n",
657 : : name);
658 : 0 : kfree(link);
659 : 0 : return failed_creating(dentry);
660 : : }
661 : 53193 : inode->i_mode = S_IFLNK | S_IRWXUGO;
662 : 53193 : inode->i_op = &debugfs_symlink_inode_operations;
663 : 53193 : inode->i_link = link;
664 : 53193 : d_instantiate(dentry, inode);
665 : 53193 : return end_creating(dentry);
666 : : }
667 : : EXPORT_SYMBOL_GPL(debugfs_create_symlink);
668 : :
669 : 0 : static void __debugfs_file_removed(struct dentry *dentry)
670 : : {
671 : 0 : struct debugfs_fsdata *fsd;
672 : :
673 : : /*
674 : : * Paired with the closing smp_mb() implied by a successful
675 : : * cmpxchg() in debugfs_file_get(): either
676 : : * debugfs_file_get() must see a dead dentry or we must see a
677 : : * debugfs_fsdata instance at ->d_fsdata here (or both).
678 : : */
679 : 0 : smp_mb();
680 [ # # ]: 0 : fsd = READ_ONCE(dentry->d_fsdata);
681 [ # # ]: 0 : if ((unsigned long)fsd & DEBUGFS_FSDATA_IS_REAL_FOPS_BIT)
682 : : return;
683 [ # # ]: 0 : if (!refcount_dec_and_test(&fsd->active_users))
684 : 0 : wait_for_completion(&fsd->active_users_drained);
685 : : }
686 : :
687 : 0 : static void remove_one(struct dentry *victim)
688 : : {
689 [ # # ]: 0 : if (d_is_reg(victim))
690 : 0 : __debugfs_file_removed(victim);
691 : 0 : simple_release_fs(&debugfs_mount, &debugfs_mount_count);
692 : 0 : }
693 : :
694 : : /**
695 : : * debugfs_remove - recursively removes a directory
696 : : * @dentry: a pointer to a the dentry of the directory to be removed. If this
697 : : * parameter is NULL or an error value, nothing will be done.
698 : : *
699 : : * This function recursively removes a directory tree in debugfs that
700 : : * was previously created with a call to another debugfs function
701 : : * (like debugfs_create_file() or variants thereof.)
702 : : *
703 : : * This function is required to be called in order for the file to be
704 : : * removed, no automatic cleanup of files will happen when a module is
705 : : * removed, you are responsible here.
706 : : */
707 : 0 : void debugfs_remove(struct dentry *dentry)
708 : : {
709 [ # # # # ]: 0 : if (IS_ERR_OR_NULL(dentry))
710 : : return;
711 : :
712 : 0 : simple_pin_fs(&debug_fs_type, &debugfs_mount, &debugfs_mount_count);
713 : 0 : simple_recursive_removal(dentry, remove_one);
714 : 0 : simple_release_fs(&debugfs_mount, &debugfs_mount_count);
715 : : }
716 : : EXPORT_SYMBOL_GPL(debugfs_remove);
717 : :
718 : : /**
719 : : * debugfs_rename - rename a file/directory in the debugfs filesystem
720 : : * @old_dir: a pointer to the parent dentry for the renamed object. This
721 : : * should be a directory dentry.
722 : : * @old_dentry: dentry of an object to be renamed.
723 : : * @new_dir: a pointer to the parent dentry where the object should be
724 : : * moved. This should be a directory dentry.
725 : : * @new_name: a pointer to a string containing the target name.
726 : : *
727 : : * This function renames a file/directory in debugfs. The target must not
728 : : * exist for rename to succeed.
729 : : *
730 : : * This function will return a pointer to old_dentry (which is updated to
731 : : * reflect renaming) if it succeeds. If an error occurs, %NULL will be
732 : : * returned.
733 : : *
734 : : * If debugfs is not enabled in the kernel, the value -%ENODEV will be
735 : : * returned.
736 : : */
737 : 0 : struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
738 : : struct dentry *new_dir, const char *new_name)
739 : : {
740 : 0 : int error;
741 : 0 : struct dentry *dentry = NULL, *trap;
742 : 0 : struct name_snapshot old_name;
743 : :
744 [ # # ]: 0 : if (IS_ERR(old_dir))
745 : : return old_dir;
746 [ # # ]: 0 : if (IS_ERR(new_dir))
747 : : return new_dir;
748 [ # # # # ]: 0 : if (IS_ERR_OR_NULL(old_dentry))
749 : : return old_dentry;
750 : :
751 : 0 : trap = lock_rename(new_dir, old_dir);
752 : : /* Source or destination directories don't exist? */
753 [ # # # # ]: 0 : if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir))
754 : 0 : goto exit;
755 : : /* Source does not exist, cyclic rename, or mountpoint? */
756 [ # # # # : 0 : if (d_really_is_negative(old_dentry) || old_dentry == trap ||
# # ]
757 [ # # ]: 0 : d_mountpoint(old_dentry))
758 : 0 : goto exit;
759 : 0 : dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
760 : : /* Lookup failed, cyclic rename or target exists? */
761 [ # # # # : 0 : if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry))
# # ]
762 : 0 : goto exit;
763 : :
764 : 0 : take_dentry_name_snapshot(&old_name, old_dentry);
765 : :
766 : 0 : error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir),
767 : : dentry, 0);
768 [ # # ]: 0 : if (error) {
769 : 0 : release_dentry_name_snapshot(&old_name);
770 : 0 : goto exit;
771 : : }
772 : 0 : d_move(old_dentry, dentry);
773 [ # # ]: 0 : fsnotify_move(d_inode(old_dir), d_inode(new_dir), &old_name.name,
774 : : d_is_dir(old_dentry),
775 : : NULL, old_dentry);
776 : 0 : release_dentry_name_snapshot(&old_name);
777 : 0 : unlock_rename(new_dir, old_dir);
778 : 0 : dput(dentry);
779 : 0 : return old_dentry;
780 : 0 : exit:
781 [ # # # # ]: 0 : if (dentry && !IS_ERR(dentry))
782 : 0 : dput(dentry);
783 : 0 : unlock_rename(new_dir, old_dir);
784 [ # # ]: 0 : if (IS_ERR(dentry))
785 : 0 : return dentry;
786 : : return ERR_PTR(-EINVAL);
787 : : }
788 : : EXPORT_SYMBOL_GPL(debugfs_rename);
789 : :
790 : : /**
791 : : * debugfs_initialized - Tells whether debugfs has been registered
792 : : */
793 : 42 : bool debugfs_initialized(void)
794 : : {
795 : 42 : return debugfs_registered;
796 : : }
797 : : EXPORT_SYMBOL_GPL(debugfs_initialized);
798 : :
799 : 21 : static int __init debugfs_init(void)
800 : : {
801 : 21 : int retval;
802 : :
803 : 21 : retval = sysfs_create_mount_point(kernel_kobj, "debug");
804 [ + - ]: 21 : if (retval)
805 : : return retval;
806 : :
807 : 21 : retval = register_filesystem(&debug_fs_type);
808 [ - + ]: 21 : if (retval)
809 : 0 : sysfs_remove_mount_point(kernel_kobj, "debug");
810 : : else
811 : 21 : debugfs_registered = true;
812 : :
813 : : return retval;
814 : : }
815 : : core_initcall(debugfs_init);
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