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Commit | Line | Data |
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1da177e4 | 1 | /* |
bd33d12f | 2 | * inode.c - part of debugfs, a tiny little debug file system |
1da177e4 LT |
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 | ||
1da177e4 LT |
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> | |
4d8ebddc | 21 | #include <linux/kobject.h> |
1da177e4 LT |
22 | #include <linux/namei.h> |
23 | #include <linux/debugfs.h> | |
4f36557f | 24 | #include <linux/fsnotify.h> |
66f54963 | 25 | #include <linux/string.h> |
d6e48686 LN |
26 | #include <linux/seq_file.h> |
27 | #include <linux/parser.h> | |
92562927 | 28 | #include <linux/magic.h> |
5a0e3ad6 | 29 | #include <linux/slab.h> |
1da177e4 | 30 | |
82aceae4 | 31 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 32 | |
1da177e4 LT |
33 | static struct vfsmount *debugfs_mount; |
34 | static int debugfs_mount_count; | |
c0f92ba9 | 35 | static bool debugfs_registered; |
1da177e4 | 36 | |
edac65ea | 37 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
38 | { |
39 | struct inode *inode = new_inode(sb); | |
1da177e4 | 40 | if (inode) { |
85fe4025 | 41 | inode->i_ino = get_next_ino(); |
1da177e4 | 42 | inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; |
1da177e4 | 43 | } |
88e412ea | 44 | return inode; |
1da177e4 LT |
45 | } |
46 | ||
d6e48686 | 47 | struct debugfs_mount_opts { |
7dc05881 EB |
48 | kuid_t uid; |
49 | kgid_t gid; | |
d6e48686 LN |
50 | umode_t mode; |
51 | }; | |
52 | ||
53 | enum { | |
54 | Opt_uid, | |
55 | Opt_gid, | |
56 | Opt_mode, | |
57 | Opt_err | |
58 | }; | |
59 | ||
60 | static const match_table_t tokens = { | |
61 | {Opt_uid, "uid=%u"}, | |
62 | {Opt_gid, "gid=%u"}, | |
63 | {Opt_mode, "mode=%o"}, | |
64 | {Opt_err, NULL} | |
65 | }; | |
66 | ||
67 | struct debugfs_fs_info { | |
68 | struct debugfs_mount_opts mount_opts; | |
69 | }; | |
70 | ||
71 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
72 | { | |
73 | substring_t args[MAX_OPT_ARGS]; | |
74 | int option; | |
75 | int token; | |
7dc05881 EB |
76 | kuid_t uid; |
77 | kgid_t gid; | |
d6e48686 LN |
78 | char *p; |
79 | ||
80 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
81 | ||
82 | while ((p = strsep(&data, ",")) != NULL) { | |
83 | if (!*p) | |
84 | continue; | |
85 | ||
86 | token = match_token(p, tokens, args); | |
87 | switch (token) { | |
88 | case Opt_uid: | |
89 | if (match_int(&args[0], &option)) | |
90 | return -EINVAL; | |
7dc05881 EB |
91 | uid = make_kuid(current_user_ns(), option); |
92 | if (!uid_valid(uid)) | |
93 | return -EINVAL; | |
94 | opts->uid = uid; | |
d6e48686 LN |
95 | break; |
96 | case Opt_gid: | |
f1688e04 | 97 | if (match_int(&args[0], &option)) |
d6e48686 | 98 | return -EINVAL; |
7dc05881 EB |
99 | gid = make_kgid(current_user_ns(), option); |
100 | if (!gid_valid(gid)) | |
101 | return -EINVAL; | |
102 | opts->gid = gid; | |
d6e48686 LN |
103 | break; |
104 | case Opt_mode: | |
105 | if (match_octal(&args[0], &option)) | |
106 | return -EINVAL; | |
107 | opts->mode = option & S_IALLUGO; | |
108 | break; | |
109 | /* | |
110 | * We might like to report bad mount options here; | |
111 | * but traditionally debugfs has ignored all mount options | |
112 | */ | |
113 | } | |
114 | } | |
115 | ||
116 | return 0; | |
117 | } | |
118 | ||
119 | static int debugfs_apply_options(struct super_block *sb) | |
120 | { | |
121 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 122 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
123 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
124 | ||
125 | inode->i_mode &= ~S_IALLUGO; | |
126 | inode->i_mode |= opts->mode; | |
127 | ||
128 | inode->i_uid = opts->uid; | |
129 | inode->i_gid = opts->gid; | |
130 | ||
131 | return 0; | |
132 | } | |
133 | ||
134 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
135 | { | |
136 | int err; | |
137 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
138 | ||
02b9984d | 139 | sync_filesystem(sb); |
d6e48686 LN |
140 | err = debugfs_parse_options(data, &fsi->mount_opts); |
141 | if (err) | |
142 | goto fail; | |
143 | ||
144 | debugfs_apply_options(sb); | |
145 | ||
146 | fail: | |
147 | return err; | |
148 | } | |
149 | ||
150 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
151 | { | |
152 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
153 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
154 | ||
7dc05881 EB |
155 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
156 | seq_printf(m, ",uid=%u", | |
157 | from_kuid_munged(&init_user_ns, opts->uid)); | |
158 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
159 | seq_printf(m, ",gid=%u", | |
160 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
161 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
162 | seq_printf(m, ",mode=%o", opts->mode); | |
163 | ||
164 | return 0; | |
165 | } | |
166 | ||
0db59e59 AV |
167 | static void debugfs_evict_inode(struct inode *inode) |
168 | { | |
169 | truncate_inode_pages_final(&inode->i_data); | |
170 | clear_inode(inode); | |
171 | if (S_ISLNK(inode->i_mode)) | |
5723cb01 | 172 | kfree(inode->i_link); |
0db59e59 AV |
173 | } |
174 | ||
d6e48686 LN |
175 | static const struct super_operations debugfs_super_operations = { |
176 | .statfs = simple_statfs, | |
177 | .remount_fs = debugfs_remount, | |
178 | .show_options = debugfs_show_options, | |
0db59e59 | 179 | .evict_inode = debugfs_evict_inode, |
d6e48686 LN |
180 | }; |
181 | ||
77b3da6e AV |
182 | static struct vfsmount *debugfs_automount(struct path *path) |
183 | { | |
184 | struct vfsmount *(*f)(void *); | |
185 | f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata; | |
2b0143b5 | 186 | return f(d_inode(path->dentry)->i_private); |
77b3da6e AV |
187 | } |
188 | ||
189 | static const struct dentry_operations debugfs_dops = { | |
190 | .d_delete = always_delete_dentry, | |
191 | .d_automount = debugfs_automount, | |
192 | }; | |
193 | ||
1da177e4 LT |
194 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
195 | { | |
196 | static struct tree_descr debug_files[] = {{""}}; | |
d6e48686 LN |
197 | struct debugfs_fs_info *fsi; |
198 | int err; | |
199 | ||
200 | save_mount_options(sb, data); | |
201 | ||
202 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); | |
203 | sb->s_fs_info = fsi; | |
204 | if (!fsi) { | |
205 | err = -ENOMEM; | |
206 | goto fail; | |
207 | } | |
208 | ||
209 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
210 | if (err) | |
211 | goto fail; | |
212 | ||
213 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
214 | if (err) | |
215 | goto fail; | |
216 | ||
217 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 218 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
219 | |
220 | debugfs_apply_options(sb); | |
221 | ||
222 | return 0; | |
1da177e4 | 223 | |
d6e48686 LN |
224 | fail: |
225 | kfree(fsi); | |
226 | sb->s_fs_info = NULL; | |
227 | return err; | |
1da177e4 LT |
228 | } |
229 | ||
fc14f2fe | 230 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 231 | int flags, const char *dev_name, |
fc14f2fe | 232 | void *data) |
1da177e4 | 233 | { |
fc14f2fe | 234 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
235 | } |
236 | ||
237 | static struct file_system_type debug_fs_type = { | |
238 | .owner = THIS_MODULE, | |
239 | .name = "debugfs", | |
fc14f2fe | 240 | .mount = debug_mount, |
1da177e4 LT |
241 | .kill_sb = kill_litter_super, |
242 | }; | |
7f78e035 | 243 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 244 | |
190afd81 | 245 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 246 | { |
190afd81 | 247 | struct dentry *dentry; |
cfa57c11 AV |
248 | int error; |
249 | ||
250 | pr_debug("debugfs: creating file '%s'\n",name); | |
251 | ||
c9e15f25 GK |
252 | if (IS_ERR(parent)) |
253 | return parent; | |
254 | ||
cfa57c11 AV |
255 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
256 | &debugfs_mount_count); | |
257 | if (error) | |
190afd81 | 258 | return ERR_PTR(error); |
1da177e4 LT |
259 | |
260 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 261 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
262 | * block. A pointer to that is in the struct vfsmount that we |
263 | * have around. | |
264 | */ | |
ef52c75e | 265 | if (!parent) |
4c1d5a64 | 266 | parent = debugfs_mount->mnt_root; |
1da177e4 | 267 | |
2b0143b5 | 268 | mutex_lock(&d_inode(parent)->i_mutex); |
cfa57c11 | 269 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 270 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
cfa57c11 | 271 | dput(dentry); |
190afd81 AV |
272 | dentry = ERR_PTR(-EEXIST); |
273 | } | |
274 | if (IS_ERR(dentry)) | |
2b0143b5 | 275 | mutex_unlock(&d_inode(parent)->i_mutex); |
190afd81 AV |
276 | return dentry; |
277 | } | |
278 | ||
5233e311 | 279 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 280 | { |
2b0143b5 | 281 | mutex_unlock(&d_inode(dentry->d_parent)->i_mutex); |
190afd81 | 282 | dput(dentry); |
5233e311 AV |
283 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
284 | return NULL; | |
285 | } | |
1da177e4 | 286 | |
5233e311 AV |
287 | static struct dentry *end_creating(struct dentry *dentry) |
288 | { | |
2b0143b5 | 289 | mutex_unlock(&d_inode(dentry->d_parent)->i_mutex); |
c3b1a350 AV |
290 | return dentry; |
291 | } | |
292 | ||
1da177e4 LT |
293 | /** |
294 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 295 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 296 | * @mode: the permission that the file should have. |
1da177e4 | 297 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 298 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
299 | * file will be created in the root of the debugfs filesystem. |
300 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 301 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
302 | * the open() call. |
303 | * @fops: a pointer to a struct file_operations that should be used for | |
304 | * this file. | |
305 | * | |
306 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
307 | * wide range of flexibility in creating a file, or a directory (if you want |
308 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
309 | * recommended to be used instead.) |
310 | * | |
311 | * This function will return a pointer to a dentry if it succeeds. This | |
312 | * pointer must be passed to the debugfs_remove() function when the file is | |
313 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 314 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 315 | * |
6468b3af | 316 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 317 | * returned. |
1da177e4 | 318 | */ |
f4ae40a6 | 319 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 320 | struct dentry *parent, void *data, |
99ac48f5 | 321 | const struct file_operations *fops) |
1da177e4 | 322 | { |
ad5abd5b | 323 | struct dentry *dentry; |
680b3024 | 324 | struct inode *inode; |
ad5abd5b AV |
325 | |
326 | if (!(mode & S_IFMT)) | |
327 | mode |= S_IFREG; | |
328 | BUG_ON(!S_ISREG(mode)); | |
329 | dentry = start_creating(name, parent); | |
330 | ||
331 | if (IS_ERR(dentry)) | |
332 | return NULL; | |
c3b1a350 | 333 | |
edac65ea | 334 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 335 | if (unlikely(!inode)) |
5233e311 | 336 | return failed_creating(dentry); |
680b3024 | 337 | |
edac65ea AV |
338 | inode->i_mode = mode; |
339 | inode->i_fop = fops ? fops : &debugfs_file_operations; | |
340 | inode->i_private = data; | |
680b3024 | 341 | d_instantiate(dentry, inode); |
2b0143b5 | 342 | fsnotify_create(d_inode(dentry->d_parent), dentry); |
5233e311 | 343 | return end_creating(dentry); |
1da177e4 LT |
344 | } |
345 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
346 | ||
e59b4e91 DH |
347 | /** |
348 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
349 | * @name: a pointer to a string containing the name of the file to create. | |
350 | * @mode: the permission that the file should have. | |
351 | * @parent: a pointer to the parent dentry for this file. This should be a | |
352 | * directory dentry if set. If this parameter is NULL, then the | |
353 | * file will be created in the root of the debugfs filesystem. | |
354 | * @data: a pointer to something that the caller will want to get to later | |
355 | * on. The inode.i_private pointer will point to this value on | |
356 | * the open() call. | |
357 | * @fops: a pointer to a struct file_operations that should be used for | |
358 | * this file. | |
359 | * @file_size: initial file size | |
360 | * | |
361 | * This is the basic "create a file" function for debugfs. It allows for a | |
362 | * wide range of flexibility in creating a file, or a directory (if you want | |
363 | * to create a directory, the debugfs_create_dir() function is | |
364 | * recommended to be used instead.) | |
365 | * | |
366 | * This function will return a pointer to a dentry if it succeeds. This | |
367 | * pointer must be passed to the debugfs_remove() function when the file is | |
368 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
369 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
370 | * | |
371 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
372 | * returned. | |
373 | */ | |
374 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
375 | struct dentry *parent, void *data, | |
376 | const struct file_operations *fops, | |
377 | loff_t file_size) | |
378 | { | |
379 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
380 | ||
381 | if (de) | |
2b0143b5 | 382 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
383 | return de; |
384 | } | |
385 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
386 | ||
1da177e4 LT |
387 | /** |
388 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
389 | * @name: a pointer to a string containing the name of the directory to |
390 | * create. | |
391 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 392 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
393 | * directory will be created in the root of the debugfs filesystem. |
394 | * | |
395 | * This function creates a directory in debugfs with the given name. | |
396 | * | |
397 | * This function will return a pointer to a dentry if it succeeds. This | |
398 | * pointer must be passed to the debugfs_remove() function when the file is | |
399 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 400 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 401 | * |
6468b3af | 402 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 403 | * returned. |
1da177e4 LT |
404 | */ |
405 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
406 | { | |
ad5abd5b | 407 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 408 | struct inode *inode; |
ad5abd5b AV |
409 | |
410 | if (IS_ERR(dentry)) | |
411 | return NULL; | |
412 | ||
edac65ea | 413 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 414 | if (unlikely(!inode)) |
5233e311 | 415 | return failed_creating(dentry); |
680b3024 | 416 | |
edac65ea AV |
417 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
418 | inode->i_op = &simple_dir_inode_operations; | |
419 | inode->i_fop = &simple_dir_operations; | |
420 | ||
421 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
422 | inc_nlink(inode); | |
680b3024 | 423 | d_instantiate(dentry, inode); |
2b0143b5 DH |
424 | inc_nlink(d_inode(dentry->d_parent)); |
425 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 426 | return end_creating(dentry); |
1da177e4 LT |
427 | } |
428 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
429 | ||
77b3da6e AV |
430 | /** |
431 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
432 | * @name: a pointer to a string containing the name of the file to create. | |
433 | * @parent: a pointer to the parent dentry for this file. This should be a | |
434 | * directory dentry if set. If this parameter is NULL, then the | |
435 | * file will be created in the root of the debugfs filesystem. | |
436 | * @f: function to be called when pathname resolution steps on that one. | |
437 | * @data: opaque argument to pass to f(). | |
438 | * | |
439 | * @f should return what ->d_automount() would. | |
440 | */ | |
441 | struct dentry *debugfs_create_automount(const char *name, | |
442 | struct dentry *parent, | |
443 | struct vfsmount *(*f)(void *), | |
444 | void *data) | |
445 | { | |
446 | struct dentry *dentry = start_creating(name, parent); | |
447 | struct inode *inode; | |
448 | ||
449 | if (IS_ERR(dentry)) | |
450 | return NULL; | |
451 | ||
452 | inode = debugfs_get_inode(dentry->d_sb); | |
453 | if (unlikely(!inode)) | |
454 | return failed_creating(dentry); | |
455 | ||
456 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; | |
457 | inode->i_flags |= S_AUTOMOUNT; | |
458 | inode->i_private = data; | |
459 | dentry->d_fsdata = (void *)f; | |
460 | d_instantiate(dentry, inode); | |
461 | return end_creating(dentry); | |
462 | } | |
463 | EXPORT_SYMBOL(debugfs_create_automount); | |
464 | ||
66f54963 PO |
465 | /** |
466 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
467 | * @name: a pointer to a string containing the name of the symbolic link to | |
468 | * create. | |
469 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 470 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
471 | * then the symbolic link will be created in the root of the debugfs |
472 | * filesystem. | |
473 | * @target: a pointer to a string containing the path to the target of the | |
474 | * symbolic link. | |
475 | * | |
476 | * This function creates a symbolic link with the given name in debugfs that | |
477 | * links to the given target path. | |
478 | * | |
479 | * This function will return a pointer to a dentry if it succeeds. This | |
480 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
481 | * link is to be removed (no automatic cleanup happens if your module is | |
482 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
483 | * returned. | |
484 | * | |
485 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 486 | * returned. |
66f54963 PO |
487 | */ |
488 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
489 | const char *target) | |
490 | { | |
ad5abd5b | 491 | struct dentry *dentry; |
680b3024 AV |
492 | struct inode *inode; |
493 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 PO |
494 | if (!link) |
495 | return NULL; | |
496 | ||
ad5abd5b | 497 | dentry = start_creating(name, parent); |
ad5abd5b | 498 | if (IS_ERR(dentry)) { |
66f54963 | 499 | kfree(link); |
ad5abd5b AV |
500 | return NULL; |
501 | } | |
502 | ||
edac65ea | 503 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 504 | if (unlikely(!inode)) { |
ad5abd5b | 505 | kfree(link); |
5233e311 | 506 | return failed_creating(dentry); |
680b3024 | 507 | } |
edac65ea | 508 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5723cb01 AV |
509 | inode->i_op = &simple_symlink_inode_operations; |
510 | inode->i_link = link; | |
680b3024 | 511 | d_instantiate(dentry, inode); |
5233e311 | 512 | return end_creating(dentry); |
66f54963 PO |
513 | } |
514 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
515 | ||
25d41d84 | 516 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
517 | { |
518 | int ret = 0; | |
519 | ||
dc3f4198 | 520 | if (simple_positive(dentry)) { |
0db59e59 | 521 | dget(dentry); |
7ceab50c | 522 | if (d_is_dir(dentry)) |
2b0143b5 | 523 | ret = simple_rmdir(d_inode(parent), dentry); |
0db59e59 | 524 | else |
2b0143b5 | 525 | simple_unlink(d_inode(parent), dentry); |
0db59e59 AV |
526 | if (!ret) |
527 | d_delete(dentry); | |
528 | dput(dentry); | |
9505e637 | 529 | } |
25d41d84 | 530 | return ret; |
9505e637 HS |
531 | } |
532 | ||
1da177e4 LT |
533 | /** |
534 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 LT |
535 | * @dentry: a pointer to a the dentry of the file or directory to be |
536 | * removed. | |
537 | * | |
538 | * This function removes a file or directory in debugfs that was previously | |
539 | * created with a call to another debugfs function (like | |
5a65980e | 540 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
541 | * |
542 | * This function is required to be called in order for the file to be | |
543 | * removed, no automatic cleanup of files will happen when a module is | |
544 | * removed, you are responsible here. | |
545 | */ | |
546 | void debugfs_remove(struct dentry *dentry) | |
547 | { | |
548 | struct dentry *parent; | |
25d41d84 JK |
549 | int ret; |
550 | ||
a59d6293 | 551 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
552 | return; |
553 | ||
554 | parent = dentry->d_parent; | |
2b0143b5 | 555 | if (!parent || d_really_is_negative(parent)) |
1da177e4 LT |
556 | return; |
557 | ||
2b0143b5 | 558 | mutex_lock(&d_inode(parent)->i_mutex); |
25d41d84 | 559 | ret = __debugfs_remove(dentry, parent); |
2b0143b5 | 560 | mutex_unlock(&d_inode(parent)->i_mutex); |
25d41d84 JK |
561 | if (!ret) |
562 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9505e637 HS |
563 | } |
564 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
565 | ||
566 | /** | |
567 | * debugfs_remove_recursive - recursively removes a directory | |
568 | * @dentry: a pointer to a the dentry of the directory to be removed. | |
569 | * | |
570 | * This function recursively removes a directory tree in debugfs that | |
571 | * was previously created with a call to another debugfs function | |
572 | * (like debugfs_create_file() or variants thereof.) | |
573 | * | |
574 | * This function is required to be called in order for the file to be | |
575 | * removed, no automatic cleanup of files will happen when a module is | |
576 | * removed, you are responsible here. | |
577 | */ | |
578 | void debugfs_remove_recursive(struct dentry *dentry) | |
579 | { | |
485d4402 | 580 | struct dentry *child, *parent; |
9505e637 | 581 | |
a59d6293 | 582 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
583 | return; |
584 | ||
585 | parent = dentry->d_parent; | |
2b0143b5 | 586 | if (!parent || d_really_is_negative(parent)) |
9505e637 HS |
587 | return; |
588 | ||
589 | parent = dentry; | |
776164c1 | 590 | down: |
2b0143b5 | 591 | mutex_lock(&d_inode(parent)->i_mutex); |
485d4402 SR |
592 | loop: |
593 | /* | |
594 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
595 | * lock, the child can be unlinked and set to be freed which can | |
596 | * use the d_u.d_child as the rcu head and corrupt this list. | |
597 | */ | |
598 | spin_lock(&parent->d_lock); | |
946e51f2 | 599 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 600 | if (!simple_positive(child)) |
776164c1 | 601 | continue; |
9505e637 | 602 | |
776164c1 | 603 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 604 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 605 | spin_unlock(&parent->d_lock); |
2b0143b5 | 606 | mutex_unlock(&d_inode(parent)->i_mutex); |
9505e637 | 607 | parent = child; |
776164c1 | 608 | goto down; |
1da177e4 | 609 | } |
485d4402 SR |
610 | |
611 | spin_unlock(&parent->d_lock); | |
612 | ||
776164c1 ON |
613 | if (!__debugfs_remove(child, parent)) |
614 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
615 | |
616 | /* | |
617 | * The parent->d_lock protects agaist child from unlinking | |
618 | * from d_subdirs. When releasing the parent->d_lock we can | |
619 | * no longer trust that the next pointer is valid. | |
620 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 621 | * simple_positive() check. |
485d4402 SR |
622 | */ |
623 | goto loop; | |
1da177e4 | 624 | } |
485d4402 | 625 | spin_unlock(&parent->d_lock); |
9505e637 | 626 | |
2b0143b5 | 627 | mutex_unlock(&d_inode(parent)->i_mutex); |
776164c1 ON |
628 | child = parent; |
629 | parent = parent->d_parent; | |
2b0143b5 | 630 | mutex_lock(&d_inode(parent)->i_mutex); |
776164c1 | 631 | |
485d4402 SR |
632 | if (child != dentry) |
633 | /* go up */ | |
634 | goto loop; | |
776164c1 ON |
635 | |
636 | if (!__debugfs_remove(child, parent)) | |
637 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
2b0143b5 | 638 | mutex_unlock(&d_inode(parent)->i_mutex); |
1da177e4 | 639 | } |
9505e637 | 640 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 641 | |
cfc94cdf JK |
642 | /** |
643 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
644 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
645 | * should be a directory dentry. | |
646 | * @old_dentry: dentry of an object to be renamed. | |
647 | * @new_dir: a pointer to the parent dentry where the object should be | |
648 | * moved. This should be a directory dentry. | |
649 | * @new_name: a pointer to a string containing the target name. | |
650 | * | |
651 | * This function renames a file/directory in debugfs. The target must not | |
652 | * exist for rename to succeed. | |
653 | * | |
654 | * This function will return a pointer to old_dentry (which is updated to | |
655 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
656 | * returned. | |
657 | * | |
658 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
659 | * returned. | |
660 | */ | |
661 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
662 | struct dentry *new_dir, const char *new_name) | |
663 | { | |
664 | int error; | |
665 | struct dentry *dentry = NULL, *trap; | |
666 | const char *old_name; | |
667 | ||
668 | trap = lock_rename(new_dir, old_dir); | |
669 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 670 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
671 | goto exit; |
672 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 673 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
674 | d_mountpoint(old_dentry)) |
675 | goto exit; | |
676 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
677 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 678 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
679 | goto exit; |
680 | ||
681 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); | |
682 | ||
2b0143b5 | 683 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
cfc94cdf JK |
684 | dentry); |
685 | if (error) { | |
686 | fsnotify_oldname_free(old_name); | |
687 | goto exit; | |
688 | } | |
689 | d_move(old_dentry, dentry); | |
2b0143b5 | 690 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name, |
e36cb0b8 | 691 | d_is_dir(old_dentry), |
5a190ae6 | 692 | NULL, old_dentry); |
cfc94cdf JK |
693 | fsnotify_oldname_free(old_name); |
694 | unlock_rename(new_dir, old_dir); | |
695 | dput(dentry); | |
696 | return old_dentry; | |
697 | exit: | |
698 | if (dentry && !IS_ERR(dentry)) | |
699 | dput(dentry); | |
700 | unlock_rename(new_dir, old_dir); | |
701 | return NULL; | |
702 | } | |
703 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
704 | ||
c0f92ba9 FW |
705 | /** |
706 | * debugfs_initialized - Tells whether debugfs has been registered | |
707 | */ | |
708 | bool debugfs_initialized(void) | |
709 | { | |
710 | return debugfs_registered; | |
711 | } | |
712 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
713 | ||
1da177e4 LT |
714 | static int __init debugfs_init(void) |
715 | { | |
716 | int retval; | |
717 | ||
f9bb4882 EB |
718 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
719 | if (retval) | |
720 | return retval; | |
1da177e4 LT |
721 | |
722 | retval = register_filesystem(&debug_fs_type); | |
723 | if (retval) | |
f9bb4882 | 724 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
725 | else |
726 | debugfs_registered = true; | |
727 | ||
1da177e4 LT |
728 | return retval; |
729 | } | |
1da177e4 | 730 | core_initcall(debugfs_init); |
1da177e4 | 731 |