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1/*
2 * file.c - part of debugfs, a tiny little debug file system
3 *
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * debugfs is for people to use instead of /proc or /sys.
12 * See Documentation/DocBook/kernel-api for more details.
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/init.h>
21#include <linux/kobject.h>
22#include <linux/namei.h>
23#include <linux/debugfs.h>
24#include <linux/fsnotify.h>
25#include <linux/string.h>
26#include <linux/magic.h>
27#include <linux/slab.h>
28
29static struct vfsmount *debugfs_mount;
30static int debugfs_mount_count;
31static bool debugfs_registered;
32
33static struct inode *debugfs_get_inode(struct super_block *sb, int mode, dev_t dev,
34 void *data, const struct file_operations *fops)
35
36{
37 struct inode *inode = new_inode(sb);
38
39 if (inode) {
40 inode->i_ino = get_next_ino();
41 inode->i_mode = mode;
42 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
43 switch (mode & S_IFMT) {
44 default:
45 init_special_inode(inode, mode, dev);
46 break;
47 case S_IFREG:
48 inode->i_fop = fops ? fops : &debugfs_file_operations;
49 inode->i_private = data;
50 break;
51 case S_IFLNK:
52 inode->i_op = &debugfs_link_operations;
53 inode->i_fop = fops;
54 inode->i_private = data;
55 break;
56 case S_IFDIR:
57 inode->i_op = &simple_dir_inode_operations;
58 inode->i_fop = fops ? fops : &simple_dir_operations;
59 inode->i_private = data;
60
61 /* directory inodes start off with i_nlink == 2
62 * (for "." entry) */
63 inc_nlink(inode);
64 break;
65 }
66 }
67 return inode;
68}
69
70/* SMP-safe */
71static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
72 int mode, dev_t dev, void *data,
73 const struct file_operations *fops)
74{
75 struct inode *inode;
76 int error = -EPERM;
77
78 if (dentry->d_inode)
79 return -EEXIST;
80
81 inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
82 if (inode) {
83 d_instantiate(dentry, inode);
84 dget(dentry);
85 error = 0;
86 }
87 return error;
88}
89
90static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, int mode,
91 void *data, const struct file_operations *fops)
92{
93 int res;
94
95 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
96 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
97 if (!res) {
98 inc_nlink(dir);
99 fsnotify_mkdir(dir, dentry);
100 }
101 return res;
102}
103
104static int debugfs_link(struct inode *dir, struct dentry *dentry, int mode,
105 void *data, const struct file_operations *fops)
106{
107 mode = (mode & S_IALLUGO) | S_IFLNK;
108 return debugfs_mknod(dir, dentry, mode, 0, data, fops);
109}
110
111static int debugfs_create(struct inode *dir, struct dentry *dentry, int mode,
112 void *data, const struct file_operations *fops)
113{
114 int res;
115
116 mode = (mode & S_IALLUGO) | S_IFREG;
117 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
118 if (!res)
119 fsnotify_create(dir, dentry);
120 return res;
121}
122
123static inline int debugfs_positive(struct dentry *dentry)
124{
125 return dentry->d_inode && !d_unhashed(dentry);
126}
127
128static int debug_fill_super(struct super_block *sb, void *data, int silent)
129{
130 static struct tree_descr debug_files[] = {{""}};
131
132 return simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
133}
134
135static struct dentry *debug_mount(struct file_system_type *fs_type,
136 int flags, const char *dev_name,
137 void *data)
138{
139 return mount_single(fs_type, flags, data, debug_fill_super);
140}
141
142static struct file_system_type debug_fs_type = {
143 .owner = THIS_MODULE,
144 .name = "debugfs",
145 .mount = debug_mount,
146 .kill_sb = kill_litter_super,
147};
148
149static int debugfs_create_by_name(const char *name, mode_t mode,
150 struct dentry *parent,
151 struct dentry **dentry,
152 void *data,
153 const struct file_operations *fops)
154{
155 int error = 0;
156
157 /* If the parent is not specified, we create it in the root.
158 * We need the root dentry to do this, which is in the super
159 * block. A pointer to that is in the struct vfsmount that we
160 * have around.
161 */
162 if (!parent)
163 parent = debugfs_mount->mnt_sb->s_root;
164
165 *dentry = NULL;
166 mutex_lock(&parent->d_inode->i_mutex);
167 *dentry = lookup_one_len(name, parent, strlen(name));
168 if (!IS_ERR(*dentry)) {
169 switch (mode & S_IFMT) {
170 case S_IFDIR:
171 error = debugfs_mkdir(parent->d_inode, *dentry, mode,
172 data, fops);
173 break;
174 case S_IFLNK:
175 error = debugfs_link(parent->d_inode, *dentry, mode,
176 data, fops);
177 break;
178 default:
179 error = debugfs_create(parent->d_inode, *dentry, mode,
180 data, fops);
181 break;
182 }
183 dput(*dentry);
184 } else
185 error = PTR_ERR(*dentry);
186 mutex_unlock(&parent->d_inode->i_mutex);
187
188 return error;
189}
190
191/**
192 * debugfs_create_file - create a file in the debugfs filesystem
193 * @name: a pointer to a string containing the name of the file to create.
194 * @mode: the permission that the file should have.
195 * @parent: a pointer to the parent dentry for this file. This should be a
196 * directory dentry if set. If this paramater is NULL, then the
197 * file will be created in the root of the debugfs filesystem.
198 * @data: a pointer to something that the caller will want to get to later
199 * on. The inode.i_private pointer will point to this value on
200 * the open() call.
201 * @fops: a pointer to a struct file_operations that should be used for
202 * this file.
203 *
204 * This is the basic "create a file" function for debugfs. It allows for a
205 * wide range of flexibility in creating a file, or a directory (if you want
206 * to create a directory, the debugfs_create_dir() function is
207 * recommended to be used instead.)
208 *
209 * This function will return a pointer to a dentry if it succeeds. This
210 * pointer must be passed to the debugfs_remove() function when the file is
211 * to be removed (no automatic cleanup happens if your module is unloaded,
212 * you are responsible here.) If an error occurs, %NULL will be returned.
213 *
214 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
215 * returned.
216 */
217struct dentry *debugfs_create_file(const char *name, mode_t mode,
218 struct dentry *parent, void *data,
219 const struct file_operations *fops)
220{
221 struct dentry *dentry = NULL;
222 int error;
223
224 pr_debug("debugfs: creating file '%s'\n",name);
225
226 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
227 &debugfs_mount_count);
228 if (error)
229 goto exit;
230
231 error = debugfs_create_by_name(name, mode, parent, &dentry,
232 data, fops);
233 if (error) {
234 dentry = NULL;
235 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
236 goto exit;
237 }
238exit:
239 return dentry;
240}
241EXPORT_SYMBOL_GPL(debugfs_create_file);
242
243/**
244 * debugfs_create_dir - create a directory in the debugfs filesystem
245 * @name: a pointer to a string containing the name of the directory to
246 * create.
247 * @parent: a pointer to the parent dentry for this file. This should be a
248 * directory dentry if set. If this paramater is NULL, then the
249 * directory will be created in the root of the debugfs filesystem.
250 *
251 * This function creates a directory in debugfs with the given name.
252 *
253 * This function will return a pointer to a dentry if it succeeds. This
254 * pointer must be passed to the debugfs_remove() function when the file is
255 * to be removed (no automatic cleanup happens if your module is unloaded,
256 * you are responsible here.) If an error occurs, %NULL will be returned.
257 *
258 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
259 * returned.
260 */
261struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
262{
263 return debugfs_create_file(name,
264 S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
265 parent, NULL, NULL);
266}
267EXPORT_SYMBOL_GPL(debugfs_create_dir);
268
269/**
270 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
271 * @name: a pointer to a string containing the name of the symbolic link to
272 * create.
273 * @parent: a pointer to the parent dentry for this symbolic link. This
274 * should be a directory dentry if set. If this paramater is NULL,
275 * then the symbolic link will be created in the root of the debugfs
276 * filesystem.
277 * @target: a pointer to a string containing the path to the target of the
278 * symbolic link.
279 *
280 * This function creates a symbolic link with the given name in debugfs that
281 * links to the given target path.
282 *
283 * This function will return a pointer to a dentry if it succeeds. This
284 * pointer must be passed to the debugfs_remove() function when the symbolic
285 * link is to be removed (no automatic cleanup happens if your module is
286 * unloaded, you are responsible here.) If an error occurs, %NULL will be
287 * returned.
288 *
289 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
290 * returned.
291 */
292struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
293 const char *target)
294{
295 struct dentry *result;
296 char *link;
297
298 link = kstrdup(target, GFP_KERNEL);
299 if (!link)
300 return NULL;
301
302 result = debugfs_create_file(name, S_IFLNK | S_IRWXUGO, parent, link,
303 NULL);
304 if (!result)
305 kfree(link);
306 return result;
307}
308EXPORT_SYMBOL_GPL(debugfs_create_symlink);
309
310static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
311{
312 int ret = 0;
313
314 if (debugfs_positive(dentry)) {
315 if (dentry->d_inode) {
316 dget(dentry);
317 switch (dentry->d_inode->i_mode & S_IFMT) {
318 case S_IFDIR:
319 ret = simple_rmdir(parent->d_inode, dentry);
320 break;
321 case S_IFLNK:
322 kfree(dentry->d_inode->i_private);
323 /* fall through */
324 default:
325 simple_unlink(parent->d_inode, dentry);
326 break;
327 }
328 if (!ret)
329 d_delete(dentry);
330 dput(dentry);
331 }
332 }
333 return ret;
334}
335
336/**
337 * debugfs_remove - removes a file or directory from the debugfs filesystem
338 * @dentry: a pointer to a the dentry of the file or directory to be
339 * removed.
340 *
341 * This function removes a file or directory in debugfs that was previously
342 * created with a call to another debugfs function (like
343 * debugfs_create_file() or variants thereof.)
344 *
345 * This function is required to be called in order for the file to be
346 * removed, no automatic cleanup of files will happen when a module is
347 * removed, you are responsible here.
348 */
349void debugfs_remove(struct dentry *dentry)
350{
351 struct dentry *parent;
352 int ret;
353
354 if (!dentry)
355 return;
356
357 parent = dentry->d_parent;
358 if (!parent || !parent->d_inode)
359 return;
360
361 mutex_lock(&parent->d_inode->i_mutex);
362 ret = __debugfs_remove(dentry, parent);
363 mutex_unlock(&parent->d_inode->i_mutex);
364 if (!ret)
365 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
366}
367EXPORT_SYMBOL_GPL(debugfs_remove);
368
369/**
370 * debugfs_remove_recursive - recursively removes a directory
371 * @dentry: a pointer to a the dentry of the directory to be removed.
372 *
373 * This function recursively removes a directory tree in debugfs that
374 * was previously created with a call to another debugfs function
375 * (like debugfs_create_file() or variants thereof.)
376 *
377 * This function is required to be called in order for the file to be
378 * removed, no automatic cleanup of files will happen when a module is
379 * removed, you are responsible here.
380 */
381void debugfs_remove_recursive(struct dentry *dentry)
382{
383 struct dentry *child;
384 struct dentry *parent;
385
386 if (!dentry)
387 return;
388
389 parent = dentry->d_parent;
390 if (!parent || !parent->d_inode)
391 return;
392
393 parent = dentry;
394 mutex_lock(&parent->d_inode->i_mutex);
395
396 while (1) {
397 /*
398 * When all dentries under "parent" has been removed,
399 * walk up the tree until we reach our starting point.
400 */
401 if (list_empty(&parent->d_subdirs)) {
402 mutex_unlock(&parent->d_inode->i_mutex);
403 if (parent == dentry)
404 break;
405 parent = parent->d_parent;
406 mutex_lock(&parent->d_inode->i_mutex);
407 }
408 child = list_entry(parent->d_subdirs.next, struct dentry,
409 d_u.d_child);
410 next_sibling:
411
412 /*
413 * If "child" isn't empty, walk down the tree and
414 * remove all its descendants first.
415 */
416 if (!list_empty(&child->d_subdirs)) {
417 mutex_unlock(&parent->d_inode->i_mutex);
418 parent = child;
419 mutex_lock(&parent->d_inode->i_mutex);
420 continue;
421 }
422 __debugfs_remove(child, parent);
423 if (parent->d_subdirs.next == &child->d_u.d_child) {
424 /*
425 * Try the next sibling.
426 */
427 if (child->d_u.d_child.next != &parent->d_subdirs) {
428 child = list_entry(child->d_u.d_child.next,
429 struct dentry,
430 d_u.d_child);
431 goto next_sibling;
432 }
433
434 /*
435 * Avoid infinite loop if we fail to remove
436 * one dentry.
437 */
438 mutex_unlock(&parent->d_inode->i_mutex);
439 break;
440 }
441 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
442 }
443
444 parent = dentry->d_parent;
445 mutex_lock(&parent->d_inode->i_mutex);
446 __debugfs_remove(dentry, parent);
447 mutex_unlock(&parent->d_inode->i_mutex);
448 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
449}
450EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
451
452/**
453 * debugfs_rename - rename a file/directory in the debugfs filesystem
454 * @old_dir: a pointer to the parent dentry for the renamed object. This
455 * should be a directory dentry.
456 * @old_dentry: dentry of an object to be renamed.
457 * @new_dir: a pointer to the parent dentry where the object should be
458 * moved. This should be a directory dentry.
459 * @new_name: a pointer to a string containing the target name.
460 *
461 * This function renames a file/directory in debugfs. The target must not
462 * exist for rename to succeed.
463 *
464 * This function will return a pointer to old_dentry (which is updated to
465 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
466 * returned.
467 *
468 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
469 * returned.
470 */
471struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
472 struct dentry *new_dir, const char *new_name)
473{
474 int error;
475 struct dentry *dentry = NULL, *trap;
476 const char *old_name;
477
478 trap = lock_rename(new_dir, old_dir);
479 /* Source or destination directories don't exist? */
480 if (!old_dir->d_inode || !new_dir->d_inode)
481 goto exit;
482 /* Source does not exist, cyclic rename, or mountpoint? */
483 if (!old_dentry->d_inode || old_dentry == trap ||
484 d_mountpoint(old_dentry))
485 goto exit;
486 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
487 /* Lookup failed, cyclic rename or target exists? */
488 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
489 goto exit;
490
491 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
492
493 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
494 dentry);
495 if (error) {
496 fsnotify_oldname_free(old_name);
497 goto exit;
498 }
499 d_move(old_dentry, dentry);
500 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
501 S_ISDIR(old_dentry->d_inode->i_mode),
502 NULL, old_dentry);
503 fsnotify_oldname_free(old_name);
504 unlock_rename(new_dir, old_dir);
505 dput(dentry);
506 return old_dentry;
507exit:
508 if (dentry && !IS_ERR(dentry))
509 dput(dentry);
510 unlock_rename(new_dir, old_dir);
511 return NULL;
512}
513EXPORT_SYMBOL_GPL(debugfs_rename);
514
515/**
516 * debugfs_initialized - Tells whether debugfs has been registered
517 */
518bool debugfs_initialized(void)
519{
520 return debugfs_registered;
521}
522EXPORT_SYMBOL_GPL(debugfs_initialized);
523
524
525static struct kobject *debug_kobj;
526
527static int __init debugfs_init(void)
528{
529 int retval;
530
531 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
532 if (!debug_kobj)
533 return -EINVAL;
534
535 retval = register_filesystem(&debug_fs_type);
536 if (retval)
537 kobject_put(debug_kobj);
538 else
539 debugfs_registered = true;
540
541 return retval;
542}
543core_initcall(debugfs_init);
544
1/*
2 * inode.c - part of debugfs, a tiny little debug file system
3 *
4 * Copyright (C) 2004 Greg Kroah-Hartman <greg@kroah.com>
5 * Copyright (C) 2004 IBM Inc.
6 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License version
9 * 2 as published by the Free Software Foundation.
10 *
11 * debugfs is for people to use instead of /proc or /sys.
12 * See Documentation/DocBook/kernel-api for more details.
13 *
14 */
15
16#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/init.h>
21#include <linux/kobject.h>
22#include <linux/namei.h>
23#include <linux/debugfs.h>
24#include <linux/fsnotify.h>
25#include <linux/string.h>
26#include <linux/seq_file.h>
27#include <linux/parser.h>
28#include <linux/magic.h>
29#include <linux/slab.h>
30
31#define DEBUGFS_DEFAULT_MODE 0700
32
33static struct vfsmount *debugfs_mount;
34static int debugfs_mount_count;
35static bool debugfs_registered;
36
37static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,
38 void *data, const struct file_operations *fops)
39
40{
41 struct inode *inode = new_inode(sb);
42
43 if (inode) {
44 inode->i_ino = get_next_ino();
45 inode->i_mode = mode;
46 inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME;
47 switch (mode & S_IFMT) {
48 default:
49 init_special_inode(inode, mode, dev);
50 break;
51 case S_IFREG:
52 inode->i_fop = fops ? fops : &debugfs_file_operations;
53 inode->i_private = data;
54 break;
55 case S_IFLNK:
56 inode->i_op = &debugfs_link_operations;
57 inode->i_private = data;
58 break;
59 case S_IFDIR:
60 inode->i_op = &simple_dir_inode_operations;
61 inode->i_fop = &simple_dir_operations;
62
63 /* directory inodes start off with i_nlink == 2
64 * (for "." entry) */
65 inc_nlink(inode);
66 break;
67 }
68 }
69 return inode;
70}
71
72/* SMP-safe */
73static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
74 umode_t mode, dev_t dev, void *data,
75 const struct file_operations *fops)
76{
77 struct inode *inode;
78 int error = -EPERM;
79
80 if (dentry->d_inode)
81 return -EEXIST;
82
83 inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
84 if (inode) {
85 d_instantiate(dentry, inode);
86 dget(dentry);
87 error = 0;
88 }
89 return error;
90}
91
92static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
93{
94 int res;
95
96 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
97 res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
98 if (!res) {
99 inc_nlink(dir);
100 fsnotify_mkdir(dir, dentry);
101 }
102 return res;
103}
104
105static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
106 void *data)
107{
108 mode = (mode & S_IALLUGO) | S_IFLNK;
109 return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
110}
111
112static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
113 void *data, const struct file_operations *fops)
114{
115 int res;
116
117 mode = (mode & S_IALLUGO) | S_IFREG;
118 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
119 if (!res)
120 fsnotify_create(dir, dentry);
121 return res;
122}
123
124static inline int debugfs_positive(struct dentry *dentry)
125{
126 return dentry->d_inode && !d_unhashed(dentry);
127}
128
129struct debugfs_mount_opts {
130 kuid_t uid;
131 kgid_t gid;
132 umode_t mode;
133};
134
135enum {
136 Opt_uid,
137 Opt_gid,
138 Opt_mode,
139 Opt_err
140};
141
142static const match_table_t tokens = {
143 {Opt_uid, "uid=%u"},
144 {Opt_gid, "gid=%u"},
145 {Opt_mode, "mode=%o"},
146 {Opt_err, NULL}
147};
148
149struct debugfs_fs_info {
150 struct debugfs_mount_opts mount_opts;
151};
152
153static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts)
154{
155 substring_t args[MAX_OPT_ARGS];
156 int option;
157 int token;
158 kuid_t uid;
159 kgid_t gid;
160 char *p;
161
162 opts->mode = DEBUGFS_DEFAULT_MODE;
163
164 while ((p = strsep(&data, ",")) != NULL) {
165 if (!*p)
166 continue;
167
168 token = match_token(p, tokens, args);
169 switch (token) {
170 case Opt_uid:
171 if (match_int(&args[0], &option))
172 return -EINVAL;
173 uid = make_kuid(current_user_ns(), option);
174 if (!uid_valid(uid))
175 return -EINVAL;
176 opts->uid = uid;
177 break;
178 case Opt_gid:
179 if (match_int(&args[0], &option))
180 return -EINVAL;
181 gid = make_kgid(current_user_ns(), option);
182 if (!gid_valid(gid))
183 return -EINVAL;
184 opts->gid = gid;
185 break;
186 case Opt_mode:
187 if (match_octal(&args[0], &option))
188 return -EINVAL;
189 opts->mode = option & S_IALLUGO;
190 break;
191 /*
192 * We might like to report bad mount options here;
193 * but traditionally debugfs has ignored all mount options
194 */
195 }
196 }
197
198 return 0;
199}
200
201static int debugfs_apply_options(struct super_block *sb)
202{
203 struct debugfs_fs_info *fsi = sb->s_fs_info;
204 struct inode *inode = sb->s_root->d_inode;
205 struct debugfs_mount_opts *opts = &fsi->mount_opts;
206
207 inode->i_mode &= ~S_IALLUGO;
208 inode->i_mode |= opts->mode;
209
210 inode->i_uid = opts->uid;
211 inode->i_gid = opts->gid;
212
213 return 0;
214}
215
216static int debugfs_remount(struct super_block *sb, int *flags, char *data)
217{
218 int err;
219 struct debugfs_fs_info *fsi = sb->s_fs_info;
220
221 sync_filesystem(sb);
222 err = debugfs_parse_options(data, &fsi->mount_opts);
223 if (err)
224 goto fail;
225
226 debugfs_apply_options(sb);
227
228fail:
229 return err;
230}
231
232static int debugfs_show_options(struct seq_file *m, struct dentry *root)
233{
234 struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
235 struct debugfs_mount_opts *opts = &fsi->mount_opts;
236
237 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
238 seq_printf(m, ",uid=%u",
239 from_kuid_munged(&init_user_ns, opts->uid));
240 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
241 seq_printf(m, ",gid=%u",
242 from_kgid_munged(&init_user_ns, opts->gid));
243 if (opts->mode != DEBUGFS_DEFAULT_MODE)
244 seq_printf(m, ",mode=%o", opts->mode);
245
246 return 0;
247}
248
249static const struct super_operations debugfs_super_operations = {
250 .statfs = simple_statfs,
251 .remount_fs = debugfs_remount,
252 .show_options = debugfs_show_options,
253};
254
255static int debug_fill_super(struct super_block *sb, void *data, int silent)
256{
257 static struct tree_descr debug_files[] = {{""}};
258 struct debugfs_fs_info *fsi;
259 int err;
260
261 save_mount_options(sb, data);
262
263 fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
264 sb->s_fs_info = fsi;
265 if (!fsi) {
266 err = -ENOMEM;
267 goto fail;
268 }
269
270 err = debugfs_parse_options(data, &fsi->mount_opts);
271 if (err)
272 goto fail;
273
274 err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
275 if (err)
276 goto fail;
277
278 sb->s_op = &debugfs_super_operations;
279
280 debugfs_apply_options(sb);
281
282 return 0;
283
284fail:
285 kfree(fsi);
286 sb->s_fs_info = NULL;
287 return err;
288}
289
290static struct dentry *debug_mount(struct file_system_type *fs_type,
291 int flags, const char *dev_name,
292 void *data)
293{
294 return mount_single(fs_type, flags, data, debug_fill_super);
295}
296
297static struct file_system_type debug_fs_type = {
298 .owner = THIS_MODULE,
299 .name = "debugfs",
300 .mount = debug_mount,
301 .kill_sb = kill_litter_super,
302};
303MODULE_ALIAS_FS("debugfs");
304
305static struct dentry *__create_file(const char *name, umode_t mode,
306 struct dentry *parent, void *data,
307 const struct file_operations *fops)
308{
309 struct dentry *dentry = NULL;
310 int error;
311
312 pr_debug("debugfs: creating file '%s'\n",name);
313
314 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
315 &debugfs_mount_count);
316 if (error)
317 goto exit;
318
319 /* If the parent is not specified, we create it in the root.
320 * We need the root dentry to do this, which is in the super
321 * block. A pointer to that is in the struct vfsmount that we
322 * have around.
323 */
324 if (!parent)
325 parent = debugfs_mount->mnt_root;
326
327 mutex_lock(&parent->d_inode->i_mutex);
328 dentry = lookup_one_len(name, parent, strlen(name));
329 if (!IS_ERR(dentry)) {
330 switch (mode & S_IFMT) {
331 case S_IFDIR:
332 error = debugfs_mkdir(parent->d_inode, dentry, mode);
333
334 break;
335 case S_IFLNK:
336 error = debugfs_link(parent->d_inode, dentry, mode,
337 data);
338 break;
339 default:
340 error = debugfs_create(parent->d_inode, dentry, mode,
341 data, fops);
342 break;
343 }
344 dput(dentry);
345 } else
346 error = PTR_ERR(dentry);
347 mutex_unlock(&parent->d_inode->i_mutex);
348
349 if (error) {
350 dentry = NULL;
351 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
352 }
353exit:
354 return dentry;
355}
356
357/**
358 * debugfs_create_file - create a file in the debugfs filesystem
359 * @name: a pointer to a string containing the name of the file to create.
360 * @mode: the permission that the file should have.
361 * @parent: a pointer to the parent dentry for this file. This should be a
362 * directory dentry if set. If this parameter is NULL, then the
363 * file will be created in the root of the debugfs filesystem.
364 * @data: a pointer to something that the caller will want to get to later
365 * on. The inode.i_private pointer will point to this value on
366 * the open() call.
367 * @fops: a pointer to a struct file_operations that should be used for
368 * this file.
369 *
370 * This is the basic "create a file" function for debugfs. It allows for a
371 * wide range of flexibility in creating a file, or a directory (if you want
372 * to create a directory, the debugfs_create_dir() function is
373 * recommended to be used instead.)
374 *
375 * This function will return a pointer to a dentry if it succeeds. This
376 * pointer must be passed to the debugfs_remove() function when the file is
377 * to be removed (no automatic cleanup happens if your module is unloaded,
378 * you are responsible here.) If an error occurs, %NULL will be returned.
379 *
380 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
381 * returned.
382 */
383struct dentry *debugfs_create_file(const char *name, umode_t mode,
384 struct dentry *parent, void *data,
385 const struct file_operations *fops)
386{
387 switch (mode & S_IFMT) {
388 case S_IFREG:
389 case 0:
390 break;
391 default:
392 BUG();
393 }
394
395 return __create_file(name, mode, parent, data, fops);
396}
397EXPORT_SYMBOL_GPL(debugfs_create_file);
398
399/**
400 * debugfs_create_dir - create a directory in the debugfs filesystem
401 * @name: a pointer to a string containing the name of the directory to
402 * create.
403 * @parent: a pointer to the parent dentry for this file. This should be a
404 * directory dentry if set. If this parameter is NULL, then the
405 * directory will be created in the root of the debugfs filesystem.
406 *
407 * This function creates a directory in debugfs with the given name.
408 *
409 * This function will return a pointer to a dentry if it succeeds. This
410 * pointer must be passed to the debugfs_remove() function when the file is
411 * to be removed (no automatic cleanup happens if your module is unloaded,
412 * you are responsible here.) If an error occurs, %NULL will be returned.
413 *
414 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
415 * returned.
416 */
417struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
418{
419 return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
420 parent, NULL, NULL);
421}
422EXPORT_SYMBOL_GPL(debugfs_create_dir);
423
424/**
425 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
426 * @name: a pointer to a string containing the name of the symbolic link to
427 * create.
428 * @parent: a pointer to the parent dentry for this symbolic link. This
429 * should be a directory dentry if set. If this parameter is NULL,
430 * then the symbolic link will be created in the root of the debugfs
431 * filesystem.
432 * @target: a pointer to a string containing the path to the target of the
433 * symbolic link.
434 *
435 * This function creates a symbolic link with the given name in debugfs that
436 * links to the given target path.
437 *
438 * This function will return a pointer to a dentry if it succeeds. This
439 * pointer must be passed to the debugfs_remove() function when the symbolic
440 * link is to be removed (no automatic cleanup happens if your module is
441 * unloaded, you are responsible here.) If an error occurs, %NULL will be
442 * returned.
443 *
444 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
445 * returned.
446 */
447struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
448 const char *target)
449{
450 struct dentry *result;
451 char *link;
452
453 link = kstrdup(target, GFP_KERNEL);
454 if (!link)
455 return NULL;
456
457 result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
458 if (!result)
459 kfree(link);
460 return result;
461}
462EXPORT_SYMBOL_GPL(debugfs_create_symlink);
463
464static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
465{
466 int ret = 0;
467
468 if (debugfs_positive(dentry)) {
469 if (dentry->d_inode) {
470 dget(dentry);
471 switch (dentry->d_inode->i_mode & S_IFMT) {
472 case S_IFDIR:
473 ret = simple_rmdir(parent->d_inode, dentry);
474 break;
475 case S_IFLNK:
476 kfree(dentry->d_inode->i_private);
477 /* fall through */
478 default:
479 simple_unlink(parent->d_inode, dentry);
480 break;
481 }
482 if (!ret)
483 d_delete(dentry);
484 dput(dentry);
485 }
486 }
487 return ret;
488}
489
490/**
491 * debugfs_remove - removes a file or directory from the debugfs filesystem
492 * @dentry: a pointer to a the dentry of the file or directory to be
493 * removed.
494 *
495 * This function removes a file or directory in debugfs that was previously
496 * created with a call to another debugfs function (like
497 * debugfs_create_file() or variants thereof.)
498 *
499 * This function is required to be called in order for the file to be
500 * removed, no automatic cleanup of files will happen when a module is
501 * removed, you are responsible here.
502 */
503void debugfs_remove(struct dentry *dentry)
504{
505 struct dentry *parent;
506 int ret;
507
508 if (IS_ERR_OR_NULL(dentry))
509 return;
510
511 parent = dentry->d_parent;
512 if (!parent || !parent->d_inode)
513 return;
514
515 mutex_lock(&parent->d_inode->i_mutex);
516 ret = __debugfs_remove(dentry, parent);
517 mutex_unlock(&parent->d_inode->i_mutex);
518 if (!ret)
519 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
520}
521EXPORT_SYMBOL_GPL(debugfs_remove);
522
523/**
524 * debugfs_remove_recursive - recursively removes a directory
525 * @dentry: a pointer to a the dentry of the directory to be removed.
526 *
527 * This function recursively removes a directory tree in debugfs that
528 * was previously created with a call to another debugfs function
529 * (like debugfs_create_file() or variants thereof.)
530 *
531 * This function is required to be called in order for the file to be
532 * removed, no automatic cleanup of files will happen when a module is
533 * removed, you are responsible here.
534 */
535void debugfs_remove_recursive(struct dentry *dentry)
536{
537 struct dentry *child, *next, *parent;
538
539 if (IS_ERR_OR_NULL(dentry))
540 return;
541
542 parent = dentry->d_parent;
543 if (!parent || !parent->d_inode)
544 return;
545
546 parent = dentry;
547 down:
548 mutex_lock(&parent->d_inode->i_mutex);
549 list_for_each_entry_safe(child, next, &parent->d_subdirs, d_u.d_child) {
550 if (!debugfs_positive(child))
551 continue;
552
553 /* perhaps simple_empty(child) makes more sense */
554 if (!list_empty(&child->d_subdirs)) {
555 mutex_unlock(&parent->d_inode->i_mutex);
556 parent = child;
557 goto down;
558 }
559 up:
560 if (!__debugfs_remove(child, parent))
561 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
562 }
563
564 mutex_unlock(&parent->d_inode->i_mutex);
565 child = parent;
566 parent = parent->d_parent;
567 mutex_lock(&parent->d_inode->i_mutex);
568
569 if (child != dentry) {
570 next = list_next_entry(child, d_u.d_child);
571 goto up;
572 }
573
574 if (!__debugfs_remove(child, parent))
575 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
576 mutex_unlock(&parent->d_inode->i_mutex);
577}
578EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
579
580/**
581 * debugfs_rename - rename a file/directory in the debugfs filesystem
582 * @old_dir: a pointer to the parent dentry for the renamed object. This
583 * should be a directory dentry.
584 * @old_dentry: dentry of an object to be renamed.
585 * @new_dir: a pointer to the parent dentry where the object should be
586 * moved. This should be a directory dentry.
587 * @new_name: a pointer to a string containing the target name.
588 *
589 * This function renames a file/directory in debugfs. The target must not
590 * exist for rename to succeed.
591 *
592 * This function will return a pointer to old_dentry (which is updated to
593 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
594 * returned.
595 *
596 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
597 * returned.
598 */
599struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
600 struct dentry *new_dir, const char *new_name)
601{
602 int error;
603 struct dentry *dentry = NULL, *trap;
604 const char *old_name;
605
606 trap = lock_rename(new_dir, old_dir);
607 /* Source or destination directories don't exist? */
608 if (!old_dir->d_inode || !new_dir->d_inode)
609 goto exit;
610 /* Source does not exist, cyclic rename, or mountpoint? */
611 if (!old_dentry->d_inode || old_dentry == trap ||
612 d_mountpoint(old_dentry))
613 goto exit;
614 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
615 /* Lookup failed, cyclic rename or target exists? */
616 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
617 goto exit;
618
619 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
620
621 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
622 dentry);
623 if (error) {
624 fsnotify_oldname_free(old_name);
625 goto exit;
626 }
627 d_move(old_dentry, dentry);
628 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
629 S_ISDIR(old_dentry->d_inode->i_mode),
630 NULL, old_dentry);
631 fsnotify_oldname_free(old_name);
632 unlock_rename(new_dir, old_dir);
633 dput(dentry);
634 return old_dentry;
635exit:
636 if (dentry && !IS_ERR(dentry))
637 dput(dentry);
638 unlock_rename(new_dir, old_dir);
639 return NULL;
640}
641EXPORT_SYMBOL_GPL(debugfs_rename);
642
643/**
644 * debugfs_initialized - Tells whether debugfs has been registered
645 */
646bool debugfs_initialized(void)
647{
648 return debugfs_registered;
649}
650EXPORT_SYMBOL_GPL(debugfs_initialized);
651
652
653static struct kobject *debug_kobj;
654
655static int __init debugfs_init(void)
656{
657 int retval;
658
659 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
660 if (!debug_kobj)
661 return -EINVAL;
662
663 retval = register_filesystem(&debug_fs_type);
664 if (retval)
665 kobject_put(debug_kobj);
666 else
667 debugfs_registered = true;
668
669 return retval;
670}
671core_initcall(debugfs_init);
672