blob: 05f2960ed7c3be5d7c4095f7fe814339ce0ae370 [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 }
Rahul Bedarkar88e412e2014-06-06 23:12:04 +053069 return inode;
Linus Torvalds1da177e2005-04-16 15:20:36 -070070}
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:
Dave Reisnerf1688e02013-01-02 08:54:37 -0500179 if (match_int(&args[0], &option))
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100180 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
Theodore Ts'o02b99842014-03-13 10:14:33 -0400221 sync_filesystem(sb);
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100222 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
Eric W. Biederman7dc05882012-04-03 14:01:31 -0700237 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));
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100243 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255static int debug_fill_super(struct super_block *sb, void *data, int silent)
256{
257 static struct tree_descr debug_files[] = {{""}};
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100258 struct debugfs_fs_info *fsi;
259 int err;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700260
Ludwig Nusseld6e48682012-01-25 11:52:28 +0100261 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700288}
289
Al Virofc14f2f2010-07-25 01:48:30 +0400290static struct dentry *debug_mount(struct file_system_type *fs_type,
David Howells454e2392006-06-23 02:02:57 -0700291 int flags, const char *dev_name,
Al Virofc14f2f2010-07-25 01:48:30 +0400292 void *data)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700293{
Al Virofc14f2f2010-07-25 01:48:30 +0400294 return mount_single(fs_type, flags, data, debug_fill_super);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700295}
296
297static struct file_system_type debug_fs_type = {
298 .owner = THIS_MODULE,
299 .name = "debugfs",
Al Virofc14f2f2010-07-25 01:48:30 +0400300 .mount = debug_mount,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700301 .kill_sb = kill_litter_super,
302};
Eric W. Biederman7f78e032013-03-02 19:39:14 -0800303MODULE_ALIAS_FS("debugfs");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700304
Chris Wright3cd52ab2012-08-09 15:40:39 -0700305static struct dentry *__create_file(const char *name, umode_t mode,
306 struct dentry *parent, void *data,
307 const struct file_operations *fops)
Al Viroc3b1a352012-06-09 20:28:22 -0400308{
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
Al Virocfa57c12012-06-09 20:33:28 -0400319 /* If the parent is not specified, we create it in the root.
Rahul Bedarkar88e412e2014-06-06 23:12:04 +0530320 * We need the root dentry to do this, which is in the super
Al Virocfa57c12012-06-09 20:33:28 -0400321 * 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
Al Virocfa57c12012-06-09 20:33:28 -0400327 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:
Al Viroac481d62012-06-09 20:40:20 -0400332 error = debugfs_mkdir(parent->d_inode, dentry, mode);
Rahul Bedarkar88e412e2014-06-06 23:12:04 +0530333
Al Virocfa57c12012-06-09 20:33:28 -0400334 break;
335 case S_IFLNK:
336 error = debugfs_link(parent->d_inode, dentry, mode,
Al Viroac481d62012-06-09 20:40:20 -0400337 data);
Al Virocfa57c12012-06-09 20:33:28 -0400338 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
Al Viroc3b1a352012-06-09 20:28:22 -0400349 if (error) {
350 dentry = NULL;
351 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
352 }
353exit:
354 return dentry;
355}
356
Linus Torvalds1da177e2005-04-16 15:20:36 -0700357/**
358 * debugfs_create_file - create a file in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359 * @name: a pointer to a string containing the name of the file to create.
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300360 * @mode: the permission that the file should have.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700361 * @parent: a pointer to the parent dentry for this file. This should be a
Masanari Iidae2278672014-02-18 22:54:36 +0900362 * directory dentry if set. If this parameter is NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700363 * 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
Theodore Ts'o8e18e292006-09-27 01:50:46 -0700365 * on. The inode.i_private pointer will point to this value on
Linus Torvalds1da177e2005-04-16 15:20:36 -0700366 * 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
Alberto Bertoglibe030e62009-10-31 18:26:52 -0300371 * 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700373 * 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,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700378 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700379 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700380 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100381 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700382 */
Al Virof4ae40a2011-07-24 04:33:43 -0400383struct dentry *debugfs_create_file(const char *name, umode_t mode,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 struct dentry *parent, void *data,
Arjan van de Ven99ac48f2006-03-28 01:56:41 -0800385 const struct file_operations *fops)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386{
Al Viroc3b1a352012-06-09 20:28:22 -0400387 switch (mode & S_IFMT) {
388 case S_IFREG:
389 case 0:
390 break;
391 default:
392 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700393 }
Al Viroc3b1a352012-06-09 20:28:22 -0400394
395 return __create_file(name, mode, parent, data, fops);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396}
397EXPORT_SYMBOL_GPL(debugfs_create_file);
398
399/**
400 * debugfs_create_dir - create a directory in the debugfs filesystem
Linus Torvalds1da177e2005-04-16 15:20:36 -0700401 * @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
Masanari Iidae2278672014-02-18 22:54:36 +0900404 * directory dentry if set. If this parameter is NULL, then the
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405 * 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,
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700412 * you are responsible here.) If an error occurs, %NULL will be returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700413 *
Randy Dunlap6468b3a2006-07-20 08:16:42 -0700414 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
Cornelia Huck873760f2007-02-14 07:57:47 +0100415 * returned.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700416 */
417struct dentry *debugfs_create_dir(const char *name, struct dentry *parent)
418{
Al Viroc3b1a352012-06-09 20:28:22 -0400419 return __create_file(name, S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700420 parent, NULL, NULL);
421}
422EXPORT_SYMBOL_GPL(debugfs_create_dir);
423
424/**
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100425 * 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
Masanari Iidae2278672014-02-18 22:54:36 +0900429 * should be a directory dentry if set. If this parameter is NULL,
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100430 * 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
Cornelia Huck873760f2007-02-14 07:57:47 +0100445 * returned.
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100446 */
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
Al Viroc3b1a352012-06-09 20:28:22 -0400457 result = __create_file(name, S_IFLNK | S_IRWXUGO, parent, link, NULL);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100458 if (!result)
459 kfree(link);
460 return result;
461}
462EXPORT_SYMBOL_GPL(debugfs_create_symlink);
463
Jan Kara25d41d82011-02-07 15:00:27 +0100464static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700465{
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500466 int ret = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700467
Linus Torvalds1da177e2005-04-16 15:20:36 -0700468 if (debugfs_positive(dentry)) {
469 if (dentry->d_inode) {
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500470 dget(dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100471 switch (dentry->d_inode->i_mode & S_IFMT) {
472 case S_IFDIR:
Mathieu Desnoyers65c33332006-11-24 13:50:09 -0500473 ret = simple_rmdir(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100474 break;
475 case S_IFLNK:
476 kfree(dentry->d_inode->i_private);
477 /* fall through */
478 default:
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 simple_unlink(parent->d_inode, dentry);
Peter Oberparleiter66f54962007-02-13 12:13:54 +0100480 break;
481 }
Mathieu Desnoyers29a7f3a2006-11-24 13:51:14 -0500482 if (!ret)
483 d_delete(dentry);
484 dput(dentry);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700485 }
486 }
Jan Kara25d41d82011-02-07 15:00:27 +0100487 return ret;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200488}
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;
Jan Kara25d41d82011-02-07 15:00:27 +0100506 int ret;
507
Arend van Spriela59d6292012-05-23 15:13:07 +0200508 if (IS_ERR_OR_NULL(dentry))
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200509 return;
510
511 parent = dentry->d_parent;
512 if (!parent || !parent->d_inode)
513 return;
514
515 mutex_lock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100516 ret = __debugfs_remove(dentry, parent);
Jes Sorensen1b1dcc12006-01-09 15:59:24 -0800517 mutex_unlock(&parent->d_inode->i_mutex);
Jan Kara25d41d82011-02-07 15:00:27 +0100518 if (!ret)
519 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700520}
521EXPORT_SYMBOL_GPL(debugfs_remove);
522
Jan Karacfc94cd2007-05-09 13:19:52 +0200523/**
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200524 * 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{
Steven Rostedt485d4402014-06-09 14:06:07 -0400537 struct dentry *child, *parent;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200538
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;
Oleg Nesterov776164c2013-07-26 17:12:56 +0200547 down:
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200548 mutex_lock(&parent->d_inode->i_mutex);
Steven Rostedt485d4402014-06-09 14:06:07 -0400549 loop:
550 /*
551 * The parent->d_subdirs is protected by the d_lock. Outside that
552 * lock, the child can be unlinked and set to be freed which can
553 * use the d_u.d_child as the rcu head and corrupt this list.
554 */
555 spin_lock(&parent->d_lock);
Al Viro946e51f2014-10-26 19:19:16 -0400556 list_for_each_entry(child, &parent->d_subdirs, d_child) {
Oleg Nesterov776164c2013-07-26 17:12:56 +0200557 if (!debugfs_positive(child))
558 continue;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200559
Oleg Nesterov776164c2013-07-26 17:12:56 +0200560 /* perhaps simple_empty(child) makes more sense */
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200561 if (!list_empty(&child->d_subdirs)) {
Steven Rostedt485d4402014-06-09 14:06:07 -0400562 spin_unlock(&parent->d_lock);
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200563 mutex_unlock(&parent->d_inode->i_mutex);
564 parent = child;
Oleg Nesterov776164c2013-07-26 17:12:56 +0200565 goto down;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200566 }
Steven Rostedt485d4402014-06-09 14:06:07 -0400567
568 spin_unlock(&parent->d_lock);
569
Oleg Nesterov776164c2013-07-26 17:12:56 +0200570 if (!__debugfs_remove(child, parent))
571 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
Steven Rostedt485d4402014-06-09 14:06:07 -0400572
573 /*
574 * The parent->d_lock protects agaist child from unlinking
575 * from d_subdirs. When releasing the parent->d_lock we can
576 * no longer trust that the next pointer is valid.
577 * Restart the loop. We'll skip this one with the
578 * debugfs_positive() check.
579 */
580 goto loop;
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200581 }
Steven Rostedt485d4402014-06-09 14:06:07 -0400582 spin_unlock(&parent->d_lock);
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200583
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200584 mutex_unlock(&parent->d_inode->i_mutex);
Oleg Nesterov776164c2013-07-26 17:12:56 +0200585 child = parent;
586 parent = parent->d_parent;
587 mutex_lock(&parent->d_inode->i_mutex);
588
Steven Rostedt485d4402014-06-09 14:06:07 -0400589 if (child != dentry)
590 /* go up */
591 goto loop;
Oleg Nesterov776164c2013-07-26 17:12:56 +0200592
593 if (!__debugfs_remove(child, parent))
594 simple_release_fs(&debugfs_mount, &debugfs_mount_count);
595 mutex_unlock(&parent->d_inode->i_mutex);
Haavard Skinnemoen9505e632008-07-01 15:14:51 +0200596}
597EXPORT_SYMBOL_GPL(debugfs_remove_recursive);
598
599/**
Jan Karacfc94cd2007-05-09 13:19:52 +0200600 * debugfs_rename - rename a file/directory in the debugfs filesystem
601 * @old_dir: a pointer to the parent dentry for the renamed object. This
602 * should be a directory dentry.
603 * @old_dentry: dentry of an object to be renamed.
604 * @new_dir: a pointer to the parent dentry where the object should be
605 * moved. This should be a directory dentry.
606 * @new_name: a pointer to a string containing the target name.
607 *
608 * This function renames a file/directory in debugfs. The target must not
609 * exist for rename to succeed.
610 *
611 * This function will return a pointer to old_dentry (which is updated to
612 * reflect renaming) if it succeeds. If an error occurs, %NULL will be
613 * returned.
614 *
615 * If debugfs is not enabled in the kernel, the value -%ENODEV will be
616 * returned.
617 */
618struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry,
619 struct dentry *new_dir, const char *new_name)
620{
621 int error;
622 struct dentry *dentry = NULL, *trap;
623 const char *old_name;
624
625 trap = lock_rename(new_dir, old_dir);
626 /* Source or destination directories don't exist? */
627 if (!old_dir->d_inode || !new_dir->d_inode)
628 goto exit;
629 /* Source does not exist, cyclic rename, or mountpoint? */
630 if (!old_dentry->d_inode || old_dentry == trap ||
631 d_mountpoint(old_dentry))
632 goto exit;
633 dentry = lookup_one_len(new_name, new_dir, strlen(new_name));
634 /* Lookup failed, cyclic rename or target exists? */
635 if (IS_ERR(dentry) || dentry == trap || dentry->d_inode)
636 goto exit;
637
638 old_name = fsnotify_oldname_init(old_dentry->d_name.name);
639
640 error = simple_rename(old_dir->d_inode, old_dentry, new_dir->d_inode,
641 dentry);
642 if (error) {
643 fsnotify_oldname_free(old_name);
644 goto exit;
645 }
646 d_move(old_dentry, dentry);
647 fsnotify_move(old_dir->d_inode, new_dir->d_inode, old_name,
Al Viro123df292009-12-25 04:57:57 -0500648 S_ISDIR(old_dentry->d_inode->i_mode),
Al Viro5a190ae2007-06-07 12:19:32 -0400649 NULL, old_dentry);
Jan Karacfc94cd2007-05-09 13:19:52 +0200650 fsnotify_oldname_free(old_name);
651 unlock_rename(new_dir, old_dir);
652 dput(dentry);
653 return old_dentry;
654exit:
655 if (dentry && !IS_ERR(dentry))
656 dput(dentry);
657 unlock_rename(new_dir, old_dir);
658 return NULL;
659}
660EXPORT_SYMBOL_GPL(debugfs_rename);
661
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100662/**
663 * debugfs_initialized - Tells whether debugfs has been registered
664 */
665bool debugfs_initialized(void)
666{
667 return debugfs_registered;
668}
669EXPORT_SYMBOL_GPL(debugfs_initialized);
670
671
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100672static struct kobject *debug_kobj;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700673
674static int __init debugfs_init(void)
675{
676 int retval;
677
Greg Kroah-Hartman0ff21e42007-11-06 10:36:58 -0800678 debug_kobj = kobject_create_and_add("debug", kernel_kobj);
Greg Kroah-Hartman191e1862007-10-29 20:13:17 +0100679 if (!debug_kobj)
680 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700681
682 retval = register_filesystem(&debug_fs_type);
683 if (retval)
Greg Kroah-Hartman197b12d2007-12-20 08:13:05 -0800684 kobject_put(debug_kobj);
Frederic Weisbeckerc0f92ba2009-03-22 23:10:44 +0100685 else
686 debugfs_registered = true;
687
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 return retval;
689}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700690core_initcall(debugfs_init);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700691