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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> |
9fd4dcec NS |
30 | #include <linux/srcu.h> |
31 | ||
32 | #include "internal.h" | |
1da177e4 | 33 | |
82aceae4 | 34 | #define DEBUGFS_DEFAULT_MODE 0700 |
d6e48686 | 35 | |
9fd4dcec NS |
36 | DEFINE_SRCU(debugfs_srcu); |
37 | ||
1da177e4 LT |
38 | static struct vfsmount *debugfs_mount; |
39 | static int debugfs_mount_count; | |
c0f92ba9 | 40 | static bool debugfs_registered; |
1da177e4 | 41 | |
edac65ea | 42 | static struct inode *debugfs_get_inode(struct super_block *sb) |
1da177e4 LT |
43 | { |
44 | struct inode *inode = new_inode(sb); | |
1da177e4 | 45 | if (inode) { |
85fe4025 | 46 | inode->i_ino = get_next_ino(); |
1b48b530 DD |
47 | inode->i_atime = inode->i_mtime = |
48 | inode->i_ctime = current_fs_time(sb); | |
1da177e4 | 49 | } |
88e412ea | 50 | return inode; |
1da177e4 LT |
51 | } |
52 | ||
d6e48686 | 53 | struct debugfs_mount_opts { |
7dc05881 EB |
54 | kuid_t uid; |
55 | kgid_t gid; | |
d6e48686 LN |
56 | umode_t mode; |
57 | }; | |
58 | ||
59 | enum { | |
60 | Opt_uid, | |
61 | Opt_gid, | |
62 | Opt_mode, | |
63 | Opt_err | |
64 | }; | |
65 | ||
66 | static const match_table_t tokens = { | |
67 | {Opt_uid, "uid=%u"}, | |
68 | {Opt_gid, "gid=%u"}, | |
69 | {Opt_mode, "mode=%o"}, | |
70 | {Opt_err, NULL} | |
71 | }; | |
72 | ||
73 | struct debugfs_fs_info { | |
74 | struct debugfs_mount_opts mount_opts; | |
75 | }; | |
76 | ||
77 | static int debugfs_parse_options(char *data, struct debugfs_mount_opts *opts) | |
78 | { | |
79 | substring_t args[MAX_OPT_ARGS]; | |
80 | int option; | |
81 | int token; | |
7dc05881 EB |
82 | kuid_t uid; |
83 | kgid_t gid; | |
d6e48686 LN |
84 | char *p; |
85 | ||
86 | opts->mode = DEBUGFS_DEFAULT_MODE; | |
87 | ||
88 | while ((p = strsep(&data, ",")) != NULL) { | |
89 | if (!*p) | |
90 | continue; | |
91 | ||
92 | token = match_token(p, tokens, args); | |
93 | switch (token) { | |
94 | case Opt_uid: | |
95 | if (match_int(&args[0], &option)) | |
96 | return -EINVAL; | |
7dc05881 EB |
97 | uid = make_kuid(current_user_ns(), option); |
98 | if (!uid_valid(uid)) | |
99 | return -EINVAL; | |
100 | opts->uid = uid; | |
d6e48686 LN |
101 | break; |
102 | case Opt_gid: | |
f1688e04 | 103 | if (match_int(&args[0], &option)) |
d6e48686 | 104 | return -EINVAL; |
7dc05881 EB |
105 | gid = make_kgid(current_user_ns(), option); |
106 | if (!gid_valid(gid)) | |
107 | return -EINVAL; | |
108 | opts->gid = gid; | |
d6e48686 LN |
109 | break; |
110 | case Opt_mode: | |
111 | if (match_octal(&args[0], &option)) | |
112 | return -EINVAL; | |
113 | opts->mode = option & S_IALLUGO; | |
114 | break; | |
115 | /* | |
116 | * We might like to report bad mount options here; | |
117 | * but traditionally debugfs has ignored all mount options | |
118 | */ | |
119 | } | |
120 | } | |
121 | ||
122 | return 0; | |
123 | } | |
124 | ||
125 | static int debugfs_apply_options(struct super_block *sb) | |
126 | { | |
127 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
2b0143b5 | 128 | struct inode *inode = d_inode(sb->s_root); |
d6e48686 LN |
129 | struct debugfs_mount_opts *opts = &fsi->mount_opts; |
130 | ||
131 | inode->i_mode &= ~S_IALLUGO; | |
132 | inode->i_mode |= opts->mode; | |
133 | ||
134 | inode->i_uid = opts->uid; | |
135 | inode->i_gid = opts->gid; | |
136 | ||
137 | return 0; | |
138 | } | |
139 | ||
140 | static int debugfs_remount(struct super_block *sb, int *flags, char *data) | |
141 | { | |
142 | int err; | |
143 | struct debugfs_fs_info *fsi = sb->s_fs_info; | |
144 | ||
02b9984d | 145 | sync_filesystem(sb); |
d6e48686 LN |
146 | err = debugfs_parse_options(data, &fsi->mount_opts); |
147 | if (err) | |
148 | goto fail; | |
149 | ||
150 | debugfs_apply_options(sb); | |
151 | ||
152 | fail: | |
153 | return err; | |
154 | } | |
155 | ||
156 | static int debugfs_show_options(struct seq_file *m, struct dentry *root) | |
157 | { | |
158 | struct debugfs_fs_info *fsi = root->d_sb->s_fs_info; | |
159 | struct debugfs_mount_opts *opts = &fsi->mount_opts; | |
160 | ||
7dc05881 EB |
161 | if (!uid_eq(opts->uid, GLOBAL_ROOT_UID)) |
162 | seq_printf(m, ",uid=%u", | |
163 | from_kuid_munged(&init_user_ns, opts->uid)); | |
164 | if (!gid_eq(opts->gid, GLOBAL_ROOT_GID)) | |
165 | seq_printf(m, ",gid=%u", | |
166 | from_kgid_munged(&init_user_ns, opts->gid)); | |
d6e48686 LN |
167 | if (opts->mode != DEBUGFS_DEFAULT_MODE) |
168 | seq_printf(m, ",mode=%o", opts->mode); | |
169 | ||
170 | return 0; | |
171 | } | |
172 | ||
0db59e59 AV |
173 | static void debugfs_evict_inode(struct inode *inode) |
174 | { | |
175 | truncate_inode_pages_final(&inode->i_data); | |
176 | clear_inode(inode); | |
177 | if (S_ISLNK(inode->i_mode)) | |
5723cb01 | 178 | kfree(inode->i_link); |
0db59e59 AV |
179 | } |
180 | ||
d6e48686 LN |
181 | static const struct super_operations debugfs_super_operations = { |
182 | .statfs = simple_statfs, | |
183 | .remount_fs = debugfs_remount, | |
184 | .show_options = debugfs_show_options, | |
0db59e59 | 185 | .evict_inode = debugfs_evict_inode, |
d6e48686 LN |
186 | }; |
187 | ||
77b3da6e AV |
188 | static struct vfsmount *debugfs_automount(struct path *path) |
189 | { | |
190 | struct vfsmount *(*f)(void *); | |
191 | f = (struct vfsmount *(*)(void *))path->dentry->d_fsdata; | |
2b0143b5 | 192 | return f(d_inode(path->dentry)->i_private); |
77b3da6e AV |
193 | } |
194 | ||
195 | static const struct dentry_operations debugfs_dops = { | |
196 | .d_delete = always_delete_dentry, | |
197 | .d_automount = debugfs_automount, | |
198 | }; | |
199 | ||
1da177e4 LT |
200 | static int debug_fill_super(struct super_block *sb, void *data, int silent) |
201 | { | |
202 | static struct tree_descr debug_files[] = {{""}}; | |
d6e48686 LN |
203 | struct debugfs_fs_info *fsi; |
204 | int err; | |
205 | ||
206 | save_mount_options(sb, data); | |
207 | ||
208 | fsi = kzalloc(sizeof(struct debugfs_fs_info), GFP_KERNEL); | |
209 | sb->s_fs_info = fsi; | |
210 | if (!fsi) { | |
211 | err = -ENOMEM; | |
212 | goto fail; | |
213 | } | |
214 | ||
215 | err = debugfs_parse_options(data, &fsi->mount_opts); | |
216 | if (err) | |
217 | goto fail; | |
218 | ||
219 | err = simple_fill_super(sb, DEBUGFS_MAGIC, debug_files); | |
220 | if (err) | |
221 | goto fail; | |
222 | ||
223 | sb->s_op = &debugfs_super_operations; | |
77b3da6e | 224 | sb->s_d_op = &debugfs_dops; |
d6e48686 LN |
225 | |
226 | debugfs_apply_options(sb); | |
227 | ||
228 | return 0; | |
1da177e4 | 229 | |
d6e48686 LN |
230 | fail: |
231 | kfree(fsi); | |
232 | sb->s_fs_info = NULL; | |
233 | return err; | |
1da177e4 LT |
234 | } |
235 | ||
fc14f2fe | 236 | static struct dentry *debug_mount(struct file_system_type *fs_type, |
454e2398 | 237 | int flags, const char *dev_name, |
fc14f2fe | 238 | void *data) |
1da177e4 | 239 | { |
fc14f2fe | 240 | return mount_single(fs_type, flags, data, debug_fill_super); |
1da177e4 LT |
241 | } |
242 | ||
243 | static struct file_system_type debug_fs_type = { | |
244 | .owner = THIS_MODULE, | |
245 | .name = "debugfs", | |
fc14f2fe | 246 | .mount = debug_mount, |
1da177e4 LT |
247 | .kill_sb = kill_litter_super, |
248 | }; | |
7f78e035 | 249 | MODULE_ALIAS_FS("debugfs"); |
1da177e4 | 250 | |
190afd81 | 251 | static struct dentry *start_creating(const char *name, struct dentry *parent) |
1da177e4 | 252 | { |
190afd81 | 253 | struct dentry *dentry; |
cfa57c11 AV |
254 | int error; |
255 | ||
256 | pr_debug("debugfs: creating file '%s'\n",name); | |
257 | ||
c9e15f25 GK |
258 | if (IS_ERR(parent)) |
259 | return parent; | |
260 | ||
cfa57c11 AV |
261 | error = simple_pin_fs(&debug_fs_type, &debugfs_mount, |
262 | &debugfs_mount_count); | |
263 | if (error) | |
190afd81 | 264 | return ERR_PTR(error); |
1da177e4 LT |
265 | |
266 | /* If the parent is not specified, we create it in the root. | |
88e412ea | 267 | * We need the root dentry to do this, which is in the super |
1da177e4 LT |
268 | * block. A pointer to that is in the struct vfsmount that we |
269 | * have around. | |
270 | */ | |
ef52c75e | 271 | if (!parent) |
4c1d5a64 | 272 | parent = debugfs_mount->mnt_root; |
1da177e4 | 273 | |
5955102c | 274 | inode_lock(d_inode(parent)); |
cfa57c11 | 275 | dentry = lookup_one_len(name, parent, strlen(name)); |
2b0143b5 | 276 | if (!IS_ERR(dentry) && d_really_is_positive(dentry)) { |
cfa57c11 | 277 | dput(dentry); |
190afd81 AV |
278 | dentry = ERR_PTR(-EEXIST); |
279 | } | |
0ee9608c DB |
280 | |
281 | if (IS_ERR(dentry)) { | |
5955102c | 282 | inode_unlock(d_inode(parent)); |
0ee9608c DB |
283 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
284 | } | |
285 | ||
190afd81 AV |
286 | return dentry; |
287 | } | |
288 | ||
5233e311 | 289 | static struct dentry *failed_creating(struct dentry *dentry) |
190afd81 | 290 | { |
5955102c | 291 | inode_unlock(d_inode(dentry->d_parent)); |
190afd81 | 292 | dput(dentry); |
5233e311 AV |
293 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); |
294 | return NULL; | |
295 | } | |
1da177e4 | 296 | |
5233e311 AV |
297 | static struct dentry *end_creating(struct dentry *dentry) |
298 | { | |
5955102c | 299 | inode_unlock(d_inode(dentry->d_parent)); |
c3b1a350 AV |
300 | return dentry; |
301 | } | |
302 | ||
1da177e4 LT |
303 | /** |
304 | * debugfs_create_file - create a file in the debugfs filesystem | |
1da177e4 | 305 | * @name: a pointer to a string containing the name of the file to create. |
be030e65 | 306 | * @mode: the permission that the file should have. |
1da177e4 | 307 | * @parent: a pointer to the parent dentry for this file. This should be a |
e227867f | 308 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
309 | * file will be created in the root of the debugfs filesystem. |
310 | * @data: a pointer to something that the caller will want to get to later | |
8e18e294 | 311 | * on. The inode.i_private pointer will point to this value on |
1da177e4 LT |
312 | * the open() call. |
313 | * @fops: a pointer to a struct file_operations that should be used for | |
314 | * this file. | |
315 | * | |
316 | * This is the basic "create a file" function for debugfs. It allows for a | |
be030e65 AB |
317 | * wide range of flexibility in creating a file, or a directory (if you want |
318 | * to create a directory, the debugfs_create_dir() function is | |
1da177e4 LT |
319 | * recommended to be used instead.) |
320 | * | |
321 | * This function will return a pointer to a dentry if it succeeds. This | |
322 | * pointer must be passed to the debugfs_remove() function when the file is | |
323 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 324 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 325 | * |
6468b3af | 326 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 327 | * returned. |
1da177e4 | 328 | */ |
f4ae40a6 | 329 | struct dentry *debugfs_create_file(const char *name, umode_t mode, |
1da177e4 | 330 | struct dentry *parent, void *data, |
99ac48f5 | 331 | const struct file_operations *fops) |
1da177e4 | 332 | { |
ad5abd5b | 333 | struct dentry *dentry; |
680b3024 | 334 | struct inode *inode; |
ad5abd5b AV |
335 | |
336 | if (!(mode & S_IFMT)) | |
337 | mode |= S_IFREG; | |
338 | BUG_ON(!S_ISREG(mode)); | |
339 | dentry = start_creating(name, parent); | |
340 | ||
341 | if (IS_ERR(dentry)) | |
342 | return NULL; | |
c3b1a350 | 343 | |
edac65ea | 344 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 345 | if (unlikely(!inode)) |
5233e311 | 346 | return failed_creating(dentry); |
680b3024 | 347 | |
edac65ea | 348 | inode->i_mode = mode; |
edac65ea | 349 | inode->i_private = data; |
9fd4dcec NS |
350 | |
351 | inode->i_fop = fops ? &debugfs_open_proxy_file_operations | |
352 | : &debugfs_noop_file_operations; | |
353 | dentry->d_fsdata = (void *)fops; | |
354 | ||
680b3024 | 355 | d_instantiate(dentry, inode); |
2b0143b5 | 356 | fsnotify_create(d_inode(dentry->d_parent), dentry); |
5233e311 | 357 | return end_creating(dentry); |
1da177e4 LT |
358 | } |
359 | EXPORT_SYMBOL_GPL(debugfs_create_file); | |
360 | ||
e59b4e91 DH |
361 | /** |
362 | * debugfs_create_file_size - create a file in the debugfs filesystem | |
363 | * @name: a pointer to a string containing the name of the file to create. | |
364 | * @mode: the permission that the file should have. | |
365 | * @parent: a pointer to the parent dentry for this file. This should be a | |
366 | * directory dentry if set. If this parameter is NULL, then the | |
367 | * file will be created in the root of the debugfs filesystem. | |
368 | * @data: a pointer to something that the caller will want to get to later | |
369 | * on. The inode.i_private pointer will point to this value on | |
370 | * the open() call. | |
371 | * @fops: a pointer to a struct file_operations that should be used for | |
372 | * this file. | |
373 | * @file_size: initial file size | |
374 | * | |
375 | * This is the basic "create a file" function for debugfs. It allows for a | |
376 | * wide range of flexibility in creating a file, or a directory (if you want | |
377 | * to create a directory, the debugfs_create_dir() function is | |
378 | * recommended to be used instead.) | |
379 | * | |
380 | * This function will return a pointer to a dentry if it succeeds. This | |
381 | * pointer must be passed to the debugfs_remove() function when the file is | |
382 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
383 | * you are responsible here.) If an error occurs, %NULL will be returned. | |
384 | * | |
385 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
386 | * returned. | |
387 | */ | |
388 | struct dentry *debugfs_create_file_size(const char *name, umode_t mode, | |
389 | struct dentry *parent, void *data, | |
390 | const struct file_operations *fops, | |
391 | loff_t file_size) | |
392 | { | |
393 | struct dentry *de = debugfs_create_file(name, mode, parent, data, fops); | |
394 | ||
395 | if (de) | |
2b0143b5 | 396 | d_inode(de)->i_size = file_size; |
e59b4e91 DH |
397 | return de; |
398 | } | |
399 | EXPORT_SYMBOL_GPL(debugfs_create_file_size); | |
400 | ||
1da177e4 LT |
401 | /** |
402 | * debugfs_create_dir - create a directory in the debugfs filesystem | |
1da177e4 LT |
403 | * @name: a pointer to a string containing the name of the directory to |
404 | * create. | |
405 | * @parent: a pointer to the parent dentry for this file. This should be a | |
e227867f | 406 | * directory dentry if set. If this parameter is NULL, then the |
1da177e4 LT |
407 | * directory will be created in the root of the debugfs filesystem. |
408 | * | |
409 | * This function creates a directory in debugfs with the given name. | |
410 | * | |
411 | * This function will return a pointer to a dentry if it succeeds. This | |
412 | * pointer must be passed to the debugfs_remove() function when the file is | |
413 | * to be removed (no automatic cleanup happens if your module is unloaded, | |
6468b3af | 414 | * you are responsible here.) If an error occurs, %NULL will be returned. |
1da177e4 | 415 | * |
6468b3af | 416 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be |
873760fb | 417 | * returned. |
1da177e4 LT |
418 | */ |
419 | struct dentry *debugfs_create_dir(const char *name, struct dentry *parent) | |
420 | { | |
ad5abd5b | 421 | struct dentry *dentry = start_creating(name, parent); |
680b3024 | 422 | struct inode *inode; |
ad5abd5b AV |
423 | |
424 | if (IS_ERR(dentry)) | |
425 | return NULL; | |
426 | ||
edac65ea | 427 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 428 | if (unlikely(!inode)) |
5233e311 | 429 | return failed_creating(dentry); |
680b3024 | 430 | |
edac65ea AV |
431 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; |
432 | inode->i_op = &simple_dir_inode_operations; | |
433 | inode->i_fop = &simple_dir_operations; | |
434 | ||
435 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ | |
436 | inc_nlink(inode); | |
680b3024 | 437 | d_instantiate(dentry, inode); |
2b0143b5 DH |
438 | inc_nlink(d_inode(dentry->d_parent)); |
439 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
5233e311 | 440 | return end_creating(dentry); |
1da177e4 LT |
441 | } |
442 | EXPORT_SYMBOL_GPL(debugfs_create_dir); | |
443 | ||
77b3da6e AV |
444 | /** |
445 | * debugfs_create_automount - create automount point in the debugfs filesystem | |
446 | * @name: a pointer to a string containing the name of the file to create. | |
447 | * @parent: a pointer to the parent dentry for this file. This should be a | |
448 | * directory dentry if set. If this parameter is NULL, then the | |
449 | * file will be created in the root of the debugfs filesystem. | |
450 | * @f: function to be called when pathname resolution steps on that one. | |
451 | * @data: opaque argument to pass to f(). | |
452 | * | |
453 | * @f should return what ->d_automount() would. | |
454 | */ | |
455 | struct dentry *debugfs_create_automount(const char *name, | |
456 | struct dentry *parent, | |
457 | struct vfsmount *(*f)(void *), | |
458 | void *data) | |
459 | { | |
460 | struct dentry *dentry = start_creating(name, parent); | |
461 | struct inode *inode; | |
462 | ||
463 | if (IS_ERR(dentry)) | |
464 | return NULL; | |
465 | ||
466 | inode = debugfs_get_inode(dentry->d_sb); | |
467 | if (unlikely(!inode)) | |
468 | return failed_creating(dentry); | |
469 | ||
470 | inode->i_mode = S_IFDIR | S_IRWXU | S_IRUGO | S_IXUGO; | |
471 | inode->i_flags |= S_AUTOMOUNT; | |
472 | inode->i_private = data; | |
473 | dentry->d_fsdata = (void *)f; | |
a8f324a4 RP |
474 | /* directory inodes start off with i_nlink == 2 (for "." entry) */ |
475 | inc_nlink(inode); | |
77b3da6e | 476 | d_instantiate(dentry, inode); |
a8f324a4 RP |
477 | inc_nlink(d_inode(dentry->d_parent)); |
478 | fsnotify_mkdir(d_inode(dentry->d_parent), dentry); | |
77b3da6e AV |
479 | return end_creating(dentry); |
480 | } | |
481 | EXPORT_SYMBOL(debugfs_create_automount); | |
482 | ||
66f54963 PO |
483 | /** |
484 | * debugfs_create_symlink- create a symbolic link in the debugfs filesystem | |
485 | * @name: a pointer to a string containing the name of the symbolic link to | |
486 | * create. | |
487 | * @parent: a pointer to the parent dentry for this symbolic link. This | |
e227867f | 488 | * should be a directory dentry if set. If this parameter is NULL, |
66f54963 PO |
489 | * then the symbolic link will be created in the root of the debugfs |
490 | * filesystem. | |
491 | * @target: a pointer to a string containing the path to the target of the | |
492 | * symbolic link. | |
493 | * | |
494 | * This function creates a symbolic link with the given name in debugfs that | |
495 | * links to the given target path. | |
496 | * | |
497 | * This function will return a pointer to a dentry if it succeeds. This | |
498 | * pointer must be passed to the debugfs_remove() function when the symbolic | |
499 | * link is to be removed (no automatic cleanup happens if your module is | |
500 | * unloaded, you are responsible here.) If an error occurs, %NULL will be | |
501 | * returned. | |
502 | * | |
503 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
873760fb | 504 | * returned. |
66f54963 PO |
505 | */ |
506 | struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent, | |
507 | const char *target) | |
508 | { | |
ad5abd5b | 509 | struct dentry *dentry; |
680b3024 AV |
510 | struct inode *inode; |
511 | char *link = kstrdup(target, GFP_KERNEL); | |
66f54963 PO |
512 | if (!link) |
513 | return NULL; | |
514 | ||
ad5abd5b | 515 | dentry = start_creating(name, parent); |
ad5abd5b | 516 | if (IS_ERR(dentry)) { |
66f54963 | 517 | kfree(link); |
ad5abd5b AV |
518 | return NULL; |
519 | } | |
520 | ||
edac65ea | 521 | inode = debugfs_get_inode(dentry->d_sb); |
680b3024 | 522 | if (unlikely(!inode)) { |
ad5abd5b | 523 | kfree(link); |
5233e311 | 524 | return failed_creating(dentry); |
680b3024 | 525 | } |
edac65ea | 526 | inode->i_mode = S_IFLNK | S_IRWXUGO; |
5723cb01 AV |
527 | inode->i_op = &simple_symlink_inode_operations; |
528 | inode->i_link = link; | |
680b3024 | 529 | d_instantiate(dentry, inode); |
5233e311 | 530 | return end_creating(dentry); |
66f54963 PO |
531 | } |
532 | EXPORT_SYMBOL_GPL(debugfs_create_symlink); | |
533 | ||
25d41d84 | 534 | static int __debugfs_remove(struct dentry *dentry, struct dentry *parent) |
9505e637 HS |
535 | { |
536 | int ret = 0; | |
537 | ||
dc3f4198 | 538 | if (simple_positive(dentry)) { |
0db59e59 | 539 | dget(dentry); |
7ceab50c | 540 | if (d_is_dir(dentry)) |
2b0143b5 | 541 | ret = simple_rmdir(d_inode(parent), dentry); |
0db59e59 | 542 | else |
2b0143b5 | 543 | simple_unlink(d_inode(parent), dentry); |
0db59e59 AV |
544 | if (!ret) |
545 | d_delete(dentry); | |
546 | dput(dentry); | |
9505e637 | 547 | } |
25d41d84 | 548 | return ret; |
9505e637 HS |
549 | } |
550 | ||
1da177e4 LT |
551 | /** |
552 | * debugfs_remove - removes a file or directory from the debugfs filesystem | |
1da177e4 | 553 | * @dentry: a pointer to a the dentry of the file or directory to be |
398dc4ad UM |
554 | * removed. If this parameter is NULL or an error value, nothing |
555 | * will be done. | |
1da177e4 LT |
556 | * |
557 | * This function removes a file or directory in debugfs that was previously | |
558 | * created with a call to another debugfs function (like | |
5a65980e | 559 | * debugfs_create_file() or variants thereof.) |
1da177e4 LT |
560 | * |
561 | * This function is required to be called in order for the file to be | |
562 | * removed, no automatic cleanup of files will happen when a module is | |
563 | * removed, you are responsible here. | |
564 | */ | |
565 | void debugfs_remove(struct dentry *dentry) | |
566 | { | |
567 | struct dentry *parent; | |
25d41d84 JK |
568 | int ret; |
569 | ||
a59d6293 | 570 | if (IS_ERR_OR_NULL(dentry)) |
1da177e4 LT |
571 | return; |
572 | ||
573 | parent = dentry->d_parent; | |
2b0143b5 | 574 | if (!parent || d_really_is_negative(parent)) |
1da177e4 LT |
575 | return; |
576 | ||
5955102c | 577 | inode_lock(d_inode(parent)); |
25d41d84 | 578 | ret = __debugfs_remove(dentry, parent); |
5955102c | 579 | inode_unlock(d_inode(parent)); |
25d41d84 JK |
580 | if (!ret) |
581 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
9fd4dcec | 582 | synchronize_srcu(&debugfs_srcu); |
9505e637 HS |
583 | } |
584 | EXPORT_SYMBOL_GPL(debugfs_remove); | |
585 | ||
586 | /** | |
587 | * debugfs_remove_recursive - recursively removes a directory | |
398dc4ad UM |
588 | * @dentry: a pointer to a the dentry of the directory to be removed. If this |
589 | * parameter is NULL or an error value, nothing will be done. | |
9505e637 HS |
590 | * |
591 | * This function recursively removes a directory tree in debugfs that | |
592 | * was previously created with a call to another debugfs function | |
593 | * (like debugfs_create_file() or variants thereof.) | |
594 | * | |
595 | * This function is required to be called in order for the file to be | |
596 | * removed, no automatic cleanup of files will happen when a module is | |
597 | * removed, you are responsible here. | |
598 | */ | |
599 | void debugfs_remove_recursive(struct dentry *dentry) | |
600 | { | |
485d4402 | 601 | struct dentry *child, *parent; |
9505e637 | 602 | |
a59d6293 | 603 | if (IS_ERR_OR_NULL(dentry)) |
9505e637 HS |
604 | return; |
605 | ||
606 | parent = dentry->d_parent; | |
2b0143b5 | 607 | if (!parent || d_really_is_negative(parent)) |
9505e637 HS |
608 | return; |
609 | ||
610 | parent = dentry; | |
776164c1 | 611 | down: |
5955102c | 612 | inode_lock(d_inode(parent)); |
485d4402 SR |
613 | loop: |
614 | /* | |
615 | * The parent->d_subdirs is protected by the d_lock. Outside that | |
616 | * lock, the child can be unlinked and set to be freed which can | |
617 | * use the d_u.d_child as the rcu head and corrupt this list. | |
618 | */ | |
619 | spin_lock(&parent->d_lock); | |
946e51f2 | 620 | list_for_each_entry(child, &parent->d_subdirs, d_child) { |
dc3f4198 | 621 | if (!simple_positive(child)) |
776164c1 | 622 | continue; |
9505e637 | 623 | |
776164c1 | 624 | /* perhaps simple_empty(child) makes more sense */ |
9505e637 | 625 | if (!list_empty(&child->d_subdirs)) { |
485d4402 | 626 | spin_unlock(&parent->d_lock); |
5955102c | 627 | inode_unlock(d_inode(parent)); |
9505e637 | 628 | parent = child; |
776164c1 | 629 | goto down; |
1da177e4 | 630 | } |
485d4402 SR |
631 | |
632 | spin_unlock(&parent->d_lock); | |
633 | ||
776164c1 ON |
634 | if (!__debugfs_remove(child, parent)) |
635 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
485d4402 SR |
636 | |
637 | /* | |
638 | * The parent->d_lock protects agaist child from unlinking | |
639 | * from d_subdirs. When releasing the parent->d_lock we can | |
640 | * no longer trust that the next pointer is valid. | |
641 | * Restart the loop. We'll skip this one with the | |
dc3f4198 | 642 | * simple_positive() check. |
485d4402 SR |
643 | */ |
644 | goto loop; | |
1da177e4 | 645 | } |
485d4402 | 646 | spin_unlock(&parent->d_lock); |
9505e637 | 647 | |
5955102c | 648 | inode_unlock(d_inode(parent)); |
776164c1 ON |
649 | child = parent; |
650 | parent = parent->d_parent; | |
5955102c | 651 | inode_lock(d_inode(parent)); |
776164c1 | 652 | |
485d4402 SR |
653 | if (child != dentry) |
654 | /* go up */ | |
655 | goto loop; | |
776164c1 ON |
656 | |
657 | if (!__debugfs_remove(child, parent)) | |
658 | simple_release_fs(&debugfs_mount, &debugfs_mount_count); | |
5955102c | 659 | inode_unlock(d_inode(parent)); |
9fd4dcec | 660 | synchronize_srcu(&debugfs_srcu); |
1da177e4 | 661 | } |
9505e637 | 662 | EXPORT_SYMBOL_GPL(debugfs_remove_recursive); |
1da177e4 | 663 | |
cfc94cdf JK |
664 | /** |
665 | * debugfs_rename - rename a file/directory in the debugfs filesystem | |
666 | * @old_dir: a pointer to the parent dentry for the renamed object. This | |
667 | * should be a directory dentry. | |
668 | * @old_dentry: dentry of an object to be renamed. | |
669 | * @new_dir: a pointer to the parent dentry where the object should be | |
670 | * moved. This should be a directory dentry. | |
671 | * @new_name: a pointer to a string containing the target name. | |
672 | * | |
673 | * This function renames a file/directory in debugfs. The target must not | |
674 | * exist for rename to succeed. | |
675 | * | |
676 | * This function will return a pointer to old_dentry (which is updated to | |
677 | * reflect renaming) if it succeeds. If an error occurs, %NULL will be | |
678 | * returned. | |
679 | * | |
680 | * If debugfs is not enabled in the kernel, the value -%ENODEV will be | |
681 | * returned. | |
682 | */ | |
683 | struct dentry *debugfs_rename(struct dentry *old_dir, struct dentry *old_dentry, | |
684 | struct dentry *new_dir, const char *new_name) | |
685 | { | |
686 | int error; | |
687 | struct dentry *dentry = NULL, *trap; | |
688 | const char *old_name; | |
689 | ||
690 | trap = lock_rename(new_dir, old_dir); | |
691 | /* Source or destination directories don't exist? */ | |
2b0143b5 | 692 | if (d_really_is_negative(old_dir) || d_really_is_negative(new_dir)) |
cfc94cdf JK |
693 | goto exit; |
694 | /* Source does not exist, cyclic rename, or mountpoint? */ | |
2b0143b5 | 695 | if (d_really_is_negative(old_dentry) || old_dentry == trap || |
cfc94cdf JK |
696 | d_mountpoint(old_dentry)) |
697 | goto exit; | |
698 | dentry = lookup_one_len(new_name, new_dir, strlen(new_name)); | |
699 | /* Lookup failed, cyclic rename or target exists? */ | |
2b0143b5 | 700 | if (IS_ERR(dentry) || dentry == trap || d_really_is_positive(dentry)) |
cfc94cdf JK |
701 | goto exit; |
702 | ||
703 | old_name = fsnotify_oldname_init(old_dentry->d_name.name); | |
704 | ||
2b0143b5 | 705 | error = simple_rename(d_inode(old_dir), old_dentry, d_inode(new_dir), |
cfc94cdf JK |
706 | dentry); |
707 | if (error) { | |
708 | fsnotify_oldname_free(old_name); | |
709 | goto exit; | |
710 | } | |
711 | d_move(old_dentry, dentry); | |
2b0143b5 | 712 | fsnotify_move(d_inode(old_dir), d_inode(new_dir), old_name, |
e36cb0b8 | 713 | d_is_dir(old_dentry), |
5a190ae6 | 714 | NULL, old_dentry); |
cfc94cdf JK |
715 | fsnotify_oldname_free(old_name); |
716 | unlock_rename(new_dir, old_dir); | |
717 | dput(dentry); | |
718 | return old_dentry; | |
719 | exit: | |
720 | if (dentry && !IS_ERR(dentry)) | |
721 | dput(dentry); | |
722 | unlock_rename(new_dir, old_dir); | |
723 | return NULL; | |
724 | } | |
725 | EXPORT_SYMBOL_GPL(debugfs_rename); | |
726 | ||
c0f92ba9 FW |
727 | /** |
728 | * debugfs_initialized - Tells whether debugfs has been registered | |
729 | */ | |
730 | bool debugfs_initialized(void) | |
731 | { | |
732 | return debugfs_registered; | |
733 | } | |
734 | EXPORT_SYMBOL_GPL(debugfs_initialized); | |
735 | ||
1da177e4 LT |
736 | static int __init debugfs_init(void) |
737 | { | |
738 | int retval; | |
739 | ||
f9bb4882 EB |
740 | retval = sysfs_create_mount_point(kernel_kobj, "debug"); |
741 | if (retval) | |
742 | return retval; | |
1da177e4 LT |
743 | |
744 | retval = register_filesystem(&debug_fs_type); | |
745 | if (retval) | |
f9bb4882 | 746 | sysfs_remove_mount_point(kernel_kobj, "debug"); |
c0f92ba9 FW |
747 | else |
748 | debugfs_registered = true; | |
749 | ||
1da177e4 LT |
750 | return retval; |
751 | } | |
1da177e4 | 752 | core_initcall(debugfs_init); |
1da177e4 | 753 |