blob: 153bb1e42e631e07b41c5d87d82fd660388ed22e [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Harry Weibd33d122011-07-16 16:45:13 +08002 * inode.c - part of debugfs, a tiny little debug file system
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
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
Linus Torvalds1da177e2005-04-16 15:20:36 -070016#include <linux/module.h>
17#include <linux/fs.h>
18#include <linux/mount.h>
19#include <linux/pagemap.h>
20#include <linux/init.h>
Randy Dunlap4d8ebdd2006-11-25 11:09:26 -080021#include <linux/kobject.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#include <linux/namei.h>
23#include <linux/debugfs.h>
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050024#include <linux/fsnotify.h>
Peter Oberparleiter66f54962007-02-13 12:13:54 +010025#include <linux/string.h>
Ludwig Nusseld6e48682012-01-25 11:52:28 +010026#include <linux/seq_file.h>
27#include <linux/parser.h>
Mimi Zohar92562922008-10-07 14:00:12 -040028#include <linux/magic.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090029#include <linux/slab.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
Kees Cook82aceae42012-08-27 13:32:15 -070031#define DEBUGFS_DEFAULT_MODE 0700
Ludwig Nusseld6e48682012-01-25 11:52:28 +010032
Linus Torvalds1da177e2005-04-16 15:20:36 -070033static struct vfsmount *debugfs_mount;
34static int debugfs_mount_count;
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +010035static bool debugfs_registered;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036
Al Virof4ae40a2011-07-24 04:33:43 -040037static struct inode *debugfs_get_inode(struct super_block *sb, umode_t mode, dev_t dev,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080038 void *data, const struct file_operations *fops)
39
Linus Torvalds1da177e2005-04-16 15:20:36 -070040{
41 struct inode *inode = new_inode(sb);
42
43 if (inode) {
Christoph Hellwig85fe4022010-10-23 11:19:54 -040044 inode->i_ino = get_next_ino();
Linus Torvalds1da177e2005-04-16 15:20:36 -070045 inode->i_mode = mode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046 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:
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080052 inode->i_fop = fops ? fops : &debugfs_file_operations;
53 inode->i_private = data;
Linus Torvalds1da177e2005-04-16 15:20:36 -070054 break;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010055 case S_IFLNK:
56 inode->i_op = &debugfs_link_operations;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080057 inode->i_private = data;
Peter Oberparleiter66f54962007-02-13 12:13:54 +010058 break;
Linus Torvalds1da177e2005-04-16 15:20:36 -070059 case S_IFDIR:
60 inode->i_op = &simple_dir_inode_operations;
Al Viroac481d62012-06-09 20:40:20 -040061 inode->i_fop = &simple_dir_operations;
Linus Torvalds1da177e2005-04-16 15:20:36 -070062
Mathieu Desnoyersbafb232e2006-11-24 13:46:30 -050063 /* directory inodes start off with i_nlink == 2
64 * (for "." entry) */
Dave Hansend8c76e62006-09-30 23:29:04 -070065 inc_nlink(inode);
Linus Torvalds1da177e2005-04-16 15:20:36 -070066 break;
67 }
68 }
69 return inode;
70}
71
72/* SMP-safe */
73static int debugfs_mknod(struct inode *dir, struct dentry *dentry,
Al Virof4ae40a2011-07-24 04:33:43 -040074 umode_t mode, dev_t dev, void *data,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080075 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -070076{
Jens Axboe71601e2b2006-06-08 10:26:39 +020077 struct inode *inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070078 int error = -EPERM;
79
80 if (dentry->d_inode)
81 return -EEXIST;
82
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -080083 inode = debugfs_get_inode(dir->i_sb, mode, dev, data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -070084 if (inode) {
85 d_instantiate(dentry, inode);
86 dget(dentry);
87 error = 0;
88 }
89 return error;
90}
91
Al Viroac481d62012-06-09 20:40:20 -040092static int debugfs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
Linus Torvalds1da177e2005-04-16 15:20:36 -070093{
94 int res;
95
96 mode = (mode & (S_IRWXUGO | S_ISVTX)) | S_IFDIR;
Al Viroac481d62012-06-09 20:40:20 -040097 res = debugfs_mknod(dir, dentry, mode, 0, NULL, NULL);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -050098 if (!res) {
Dave Hansend8c76e62006-09-30 23:29:04 -070099 inc_nlink(dir);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500100 fsnotify_mkdir(dir, dentry);
101 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102 return res;
103}
104
Al Virof4ae40a2011-07-24 04:33:43 -0400105static int debugfs_link(struct inode *dir, struct dentry *dentry, umode_t mode,
Al Viroac481d62012-06-09 20:40:20 -0400106 void *data)
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100107{
108 mode = (mode & S_IALLUGO) | S_IFLNK;
Al Viroac481d62012-06-09 20:40:20 -0400109 return debugfs_mknod(dir, dentry, mode, 0, data, NULL);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100110}
111
Al Virof4ae40a2011-07-24 04:33:43 -0400112static int debugfs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800113 void *data, const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700114{
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500115 int res;
116
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 mode = (mode & S_IALLUGO) | S_IFREG;
Mathieu Desnoyersd3a3b0a2009-11-17 14:40:26 -0800118 res = debugfs_mknod(dir, dentry, mode, 0, data, fops);
Mathieu Desnoyers4f365572006-11-24 13:45:37 -0500119 if (!res)
120 fsnotify_create(dir, dentry);
121 return res;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
123
124static inline int debugfs_positive(struct dentry *dentry)
125{
126 return dentry->d_inode && !d_unhashed(dentry);
127}
128
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100129struct debugfs_mount_opts {
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700130 kuid_t uid;
131 kgid_t gid;
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100132 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;
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700158 kuid_t uid;
159 kgid_t gid;
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100160 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;
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700173 uid = make_kuid(current_user_ns(), option);
174 if (!uid_valid(uid))
175 return -EINVAL;
176 opts->uid = uid;
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100177 break;
178 case Opt_gid:
179 if (match_octal(&args[0], &option))
180 return -EINVAL;
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700181 gid = make_kgid(current_user_ns(), option);
182 if (!gid_valid(gid))
183 return -EINVAL;
184 opts->gid = gid;
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100185 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 err = debugfs_parse_options(data, &fsi->mount_opts);
222 if (err)
223 goto fail;
224
225 debugfs_apply_options(sb);
226
227fail:
228 return err;
229}
230
231static int debugfs_show_options(struct seq_file *m, struct dentry *root)
232{
233 struct debugfs_fs_info *fsi = root->d_sb->s_fs_info;
234 struct debugfs_mount_opts *opts = &fsi->mount_opts;
235
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700236 if (!uid_eq(opts->uid, GLOBAL_ROOT_UID))
237 seq_printf(m, ",uid=%u",
238 from_kuid_munged(&init_user_ns, opts->uid));
239 if (!gid_eq(opts->gid, GLOBAL_ROOT_GID))
240 seq_printf(m, ",gid=%u",
241 from_kgid_munged(&init_user_ns, opts->gid));
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100242 if (opts->mode != DEBUGFS_DEFAULT_MODE)
243 seq_printf(m, ",mode=%o", opts->mode);
244
245 return 0;
246}
247
248static const struct super_operations debugfs_super_operations = {
249 .statfs = simple_statfs,
250 .remount_fs = debugfs_remount,
251 .show_options = debugfs_show_options,
252};
253
Linus Torvalds1da177e2005-04-16 15:20:36 -0700254static int debug_fill_super(struct super_block *sb, void *data, int silent)
255{
256 static struct tree_descr debug_files[] = {{""}};
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100257 struct debugfs_fs_info *fsi;
258 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700259
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100260 save_mount_options(sb, data);
261
262 fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL);
263 sb->s_fs_info = fsi;
264 if (!fsi) {
265 err = -ENOMEM;
266 goto fail;
267 }
268
269 err = debugfs_parse_options(data, &fsi->mount_opts);
270 if (err)
271 goto fail;
272
273 err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files);
274 if (err)
275 goto fail;
276
277 sb->s_op = &debugfs_super_operations;
278
279 debugfs_apply_options(sb);
280
281 return 0;
282
283fail:
284 kfree(fsi);
285 sb->s_fs_info = NULL;
286 return err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700287}
288
Al Virofc14f2f2010-07-25 01:48:30 +0400289static struct dentry *debug_mount(struct file_system_type *fs_type,
David Howells454e2392006-06-23 02:02:57 -0700290 int flags, const char *dev_name,
Al Virofc14f2f2010-07-25 01:48:30 +0400291 void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700292{
Al Virofc14f2f2010-07-25 01:48:30 +0400293 return mount_single(fs_type, flags, data, debug_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700294}
295
296static struct file_system_type debug_fs_type = {
297 .owner = THIS_MODULE,
298 .name = "debugfs",
Al Virofc14f2f2010-07-25 01:48:30 +0400299 .mount = debug_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700300 .kill_sb = kill_litter_super,
301};
302
Chris Wright3cd52ab2012-08-09 15:40:39 -0700303static struct dentry *__create_file(const char *name, umode_t mode,
304 struct dentry *parent, void *data,
305 const struct file_operations *fops)
Al Viroc3b1a352012-06-09 20:28:22 -0400306{
307 struct dentry *dentry = NULL;
308 int error;
309
310 pr_debug("debugfs: creating file '%s'\n",name);
311
312 error = simple_pin_fs(&debug_fs_type, &debugfs_mount,
313 &debugfs_mount_count);
314 if (error)
315 goto exit;
316
Al Virocfa57c12012-06-09 20:33:28 -0400317 /* If the parent is not specified, we create it in the root.
318 * We need the root dentry to do this, which is in the super
319 * block. A pointer to that is in the struct vfsmount that we
320 * have around.
321 */
322 if (!parent)
323 parent = debugfs_mount->mnt_root;
324
325 dentry = NULL;
326 mutex_lock(&parent->d_inode->i_mutex);
327 dentry = lookup_one_len(name, parent, strlen(name));
328 if (!IS_ERR(dentry)) {
329 switch (mode & S_IFMT) {
330 case S_IFDIR:
Al Viroac481d62012-06-09 20:40:20 -0400331 error = debugfs_mkdir(parent->d_inode, dentry, mode);
332
Al Virocfa57c12012-06-09 20:33:28 -0400333 break;
334 case S_IFLNK:
335 error = debugfs_link(parent->d_inode, dentry, mode,
Al Viroac481d62012-06-09 20:40:20 -0400336 data);
Al Virocfa57c12012-06-09 20:33:28 -0400337 break;
338 default:
339 error = debugfs_create(parent->d_inode, dentry, mode,
340 data, fops);
341 break;
342 }
343 dput(dentry);
344 } else
345 error = PTR_ERR(dentry);
346 mutex_unlock(&parent->d_inode->i_mutex);
347
Al Viroc3b1a352012-06-09 20:28:22 -0400348 if (error) {
349 dentry = NULL;
350 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
351 }
352exit:
353 return dentry;
354}
355
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356/**
357 * debugfs_create_file - create a file in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700358 * @name: a pointer to a string containing the name of the file to create.
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300359 * @mode: the permission that the file should have.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700360 * @parent: a pointer to the parent dentry for this file. This should be a
361 * directory dentry if set. If this paramater is NULL, then the
362 * file will be created in the root of the debugfs filesystem.
363 * @data: a pointer to something that the caller will want to get to later
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700364 * on. The inode.i_private pointer will point to this value on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700365 * the open() call.
366 * @fops: a pointer to a struct file_operations that should be used for
367 * this file.
368 *
369 * This is the basic "create a file" function for debugfs. It allows for a
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300370 * wide range of flexibility in creating a file, or a directory (if you want
371 * to create a directory, the debugfs_create_dir() function is
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 * recommended to be used instead.)
373 *
374 * This function will return a pointer to a dentry if it succeeds. This
375 * pointer must be passed to the debugfs_remove() function when the file is
376 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700377 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700378 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700379 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100380 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700381 */
Al Virof4ae40a2011-07-24 04:33:43 -0400382struct dentry *debugfs_create_file(const char *name, umode_t mode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700383 struct dentry *parent, void *data,
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800384 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700385{
Al Viroc3b1a352012-06-09 20:28:22 -0400386 switch (mode & S_IFMT) {
387 case S_IFREG:
388 case 0:
389 break;
390 default:
391 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700392 }
Al Viroc3b1a352012-06-09 20:28:22 -0400393
394 return __create_file(name, mode, parent, data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395}
396EXPORT_SYMBOL_GPL(debugfs_create_file);
397
398/**
399 * debugfs_create_dir - create a directory in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400 * @name: a pointer to a string containing the name of the directory to
401 * create.
402 * @parent: a pointer to the parent dentry for this file. This should be a
403 * directory dentry if set. If this paramater is NULL, then the
404 * directory will be created in the root of the debugfs filesystem.
405 *
406 * This function creates a directory in debugfs with the given name.
407 *
408 * This function will return a pointer to a dentry if it succeeds. This
409 * pointer must be passed to the debugfs_remove() function when the file is
410 * to be removed (no automatic cleanup happens if your module is unloaded,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700411 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700412 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700413 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100414 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700415 */
416struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
417{
Al Viroc3b1a352012-06-09 20:28:22 -0400418 return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700419 parent, NULL, NULL);
420}
421EXPORT_SYMBOL_GPL(debugfs_create_dir);
422
423/**
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100424 * debugfs_create_symlink- create a symbolic link in the debugfs filesystem
425 * @name: a pointer to a string containing the name of the symbolic link to
426 * create.
427 * @parent: a pointer to the parent dentry for this symbolic link. This
428 * should be a directory dentry if set. If this paramater is NULL,
429 * then the symbolic link will be created in the root of the debugfs
430 * filesystem.
431 * @target: a pointer to a string containing the path to the target of the
432 * symbolic link.
433 *
434 * This function creates a symbolic link with the given name in debugfs that
435 * links to the given target path.
436 *
437 * This function will return a pointer to a dentry if it succeeds. This
438 * pointer must be passed to the debugfs_remove() function when the symbolic
439 * link is to be removed (no automatic cleanup happens if your module is
440 * unloaded, you are responsible here.) If an error occurs, %NULL will be
441 * returned.
442 *
443 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100444 * returned.
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100445 */
446struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
447 const char *target)
448{
449 struct dentry *result;
450 char *link;
451
452 link = kstrdup(target, GFP_KERNEL);
453 if (!link)
454 return NULL;
455
Al Viroc3b1a352012-06-09 20:28:22 -0400456 result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100457 if (!result)
458 kfree(link);
459 return result;
460}
461EXPORT_SYMBOL_GPL(debugfs_create_symlink);
462
Jan Kara25d41d82011-02-07 15:00:27 +0100463static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464{
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500465 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467 if (debugfs_positive(dentry)) {
468 if (dentry->d_inode) {
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500469 dget(dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100470 switch (dentry->d_inode->i_mode & S_IFMT) {
471 case S_IFDIR:
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500472 ret = simple_rmdir(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100473 break;
474 case S_IFLNK:
475 kfree(dentry->d_inode->i_private);
476 /* fall through */
477 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700478 simple_unlink(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100479 break;
480 }
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500481 if (!ret)
482 d_delete(dentry);
483 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484 }
485 }
Jan Kara25d41d82011-02-07 15:00:27 +0100486 return ret;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200487}
488
489/**
490 * debugfs_remove - removes a file or directory from the debugfs filesystem
491 * @dentry: a pointer to a the dentry of the file or directory to be
492 * removed.
493 *
494 * This function removes a file or directory in debugfs that was previously
495 * created with a call to another debugfs function (like
496 * debugfs_create_file() or variants thereof.)
497 *
498 * This function is required to be called in order for the file to be
499 * removed, no automatic cleanup of files will happen when a module is
500 * removed, you are responsible here.
501 */
502void debugfs_remove(struct dentry *dentry)
503{
504 struct dentry *parent;
Jan Kara25d41d82011-02-07 15:00:27 +0100505 int ret;
506
Arend van Spriela59d6292012-05-23 15:13:07 +0200507 if (IS_ERR_OR_NULL(dentry))
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200508 return;
509
510 parent = dentry->d_parent;
511 if (!parent || !parent->d_inode)
512 return;
513
514 mutex_lock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100515 ret = __debugfs_remove(dentry, parent);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800516 mutex_unlock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100517 if (!ret)
518 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700519}
520EXPORT_SYMBOL_GPL(debugfs_remove);
521
Jan Karacfc94cd2007-05-09 13:19:52 +0200522/**
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200523 * debugfs_remove_recursive - recursively removes a directory
524 * @dentry: a pointer to a the dentry of the directory to be removed.
525 *
526 * This function recursively removes a directory tree in debugfs that
527 * was previously created with a call to another debugfs function
528 * (like debugfs_create_file() or variants thereof.)
529 *
530 * This function is required to be called in order for the file to be
531 * removed, no automatic cleanup of files will happen when a module is
532 * removed, you are responsible here.
533 */
534void debugfs_remove_recursive(struct dentry *dentry)
535{
536 struct dentry *child;
537 struct dentry *parent;
538
Arend van Spriela59d6292012-05-23 15:13:07 +0200539 if (IS_ERR_OR_NULL(dentry))
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200540 return;
541
542 parent = dentry->d_parent;
543 if (!parent || !parent->d_inode)
544 return;
545
546 parent = dentry;
547 mutex_lock(&parent->d_inode->i_mutex);
548
549 while (1) {
550 /*
551 * When all dentries under "parent" has been removed,
552 * walk up the tree until we reach our starting point.
553 */
554 if (list_empty(&parent->d_subdirs)) {
555 mutex_unlock(&parent->d_inode->i_mutex);
556 if (parent == dentry)
557 break;
558 parent = parent->d_parent;
559 mutex_lock(&parent->d_inode->i_mutex);
560 }
561 child = list_entry(parent->d_subdirs.next, struct dentry,
562 d_u.d_child);
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400563 next_sibling:
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200564
565 /*
566 * If "child" isn't empty, walk down the tree and
567 * remove all its descendants first.
568 */
569 if (!list_empty(&child->d_subdirs)) {
570 mutex_unlock(&parent->d_inode->i_mutex);
571 parent = child;
572 mutex_lock(&parent->d_inode->i_mutex);
573 continue;
574 }
575 __debugfs_remove(child, parent);
576 if (parent->d_subdirs.next == &child->d_u.d_child) {
577 /*
Steven Rostedt56a83cc2009-04-25 00:39:40 -0400578 * Try the next sibling.
579 */
580 if (child->d_u.d_child.next != &parent->d_subdirs) {
581 child = list_entry(child->d_u.d_child.next,
582 struct dentry,
583 d_u.d_child);
584 goto next_sibling;
585 }
586
587 /*
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200588 * Avoid infinite loop if we fail to remove
589 * one dentry.
590 */
591 mutex_unlock(&parent->d_inode->i_mutex);
592 break;
593 }
594 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
595 }
596
597 parent = dentry->d_parent;
598 mutex_lock(&parent->d_inode->i_mutex);
599 __debugfs_remove(dentry, parent);
600 mutex_unlock(&parent->d_inode->i_mutex);
601 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
602}
603EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
604
605/**
Jan Karacfc94cd2007-05-09 13:19:52 +0200606 * debugfs_rename - rename a file/directory in the debugfs filesystem
607 * @old_dir: a pointer to the parent dentry for the renamed object. This
608 * should be a directory dentry.
609 * @old_dentry: dentry of an object to be renamed.
610 * @new_dir: a pointer to the parent dentry where the object should be
611 * moved. This should be a directory dentry.
612 * @new_name: a pointer to a string containing the target name.
613 *
614 * This function renames a file/directory in debugfs. The target must not
615 * exist for rename to succeed.
616 *
617 * This function will return a pointer to old_dentry (which is updated to
618 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
619 * returned.
620 *
621 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
622 * returned.
623 */
624struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
625 struct dentry *new_dir, const char *new_name)
626{
627 int error;
628 struct dentry *dentry = NULL, *trap;
629 const char *old_name;
630
631 trap = lock_rename(new_dir, old_dir);
632 /* Source or destination directories don't exist? */
633 if (!old_dir->d_inode || !new_dir->d_inode)
634 goto exit;
635 /* Source does not exist, cyclic rename, or mountpoint? */
636 if (!old_dentry->d_inode || old_dentry == trap ||
637 d_mountpoint(old_dentry))
638 goto exit;
639 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
640 /* Lookup failed, cyclic rename or target exists? */
641 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
642 goto exit;
643
644 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
645
646 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
647 dentry);
648 if (error) {
649 fsnotify_oldname_free(old_name);
650 goto exit;
651 }
652 d_move(old_dentry, dentry);
653 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
Al Viro123df292009-12-25 04:57:57 -0500654 S_ISDIR(old_dentry->d_inode->i_mode),
Al Viro5a190ae2007-06-07 12:19:32 -0400655 NULL, old_dentry);
Jan Karacfc94cd2007-05-09 13:19:52 +0200656 fsnotify_oldname_free(old_name);
657 unlock_rename(new_dir, old_dir);
658 dput(dentry);
659 return old_dentry;
660exit:
661 if (dentry && !IS_ERR(dentry))
662 dput(dentry);
663 unlock_rename(new_dir, old_dir);
664 return NULL;
665}
666EXPORT_SYMBOL_GPL(debugfs_rename);
667
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100668/**
669 * debugfs_initialized - Tells whether debugfs has been registered
670 */
671bool debugfs_initialized(void)
672{
673 return debugfs_registered;
674}
675EXPORT_SYMBOL_GPL(debugfs_initialized);
676
677
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100678static struct kobject *debug_kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700679
680static int __init debugfs_init(void)
681{
682 int retval;
683
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800684 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100685 if (!debug_kobj)
686 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700687
688 retval = register_filesystem(&debug_fs_type);
689 if (retval)
Greg Kroah-Hartman197b12d2007-12-20 08:13:05 -0800690 kobject_put(debug_kobj);
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100691 else
692 debugfs_registered = true;
693
Linus Torvalds1da177e2005-04-16 15:20:36 -0700694 return retval;
695}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700696core_initcall(debugfs_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700697