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Commit | Line | Data |
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b8441ed2 TH |
1 | /* |
2 | * kernfs.h - pseudo filesystem decoupled from vfs locking | |
3 | * | |
4 | * This file is released under the GPLv2. | |
5 | */ | |
6 | ||
7 | #ifndef __LINUX_KERNFS_H | |
8 | #define __LINUX_KERNFS_H | |
9 | ||
879f40d1 | 10 | #include <linux/kernel.h> |
5d0e26bb | 11 | #include <linux/err.h> |
dd8a5b03 TH |
12 | #include <linux/list.h> |
13 | #include <linux/mutex.h> | |
bc755553 | 14 | #include <linux/idr.h> |
517e64f5 | 15 | #include <linux/lockdep.h> |
cf9e5a73 TH |
16 | #include <linux/rbtree.h> |
17 | #include <linux/atomic.h> | |
abd54f02 | 18 | #include <linux/wait.h> |
879f40d1 | 19 | |
5d60418e | 20 | struct file; |
917f56ca | 21 | struct dentry; |
5d60418e | 22 | struct iattr; |
dd8a5b03 TH |
23 | struct seq_file; |
24 | struct vm_area_struct; | |
4b93dc9b TH |
25 | struct super_block; |
26 | struct file_system_type; | |
5d60418e | 27 | |
c525aadd TH |
28 | struct kernfs_open_node; |
29 | struct kernfs_iattrs; | |
cf9e5a73 TH |
30 | |
31 | enum kernfs_node_type { | |
df23fc39 TH |
32 | KERNFS_DIR = 0x0001, |
33 | KERNFS_FILE = 0x0002, | |
34 | KERNFS_LINK = 0x0004, | |
cf9e5a73 TH |
35 | }; |
36 | ||
df23fc39 | 37 | #define KERNFS_TYPE_MASK 0x000f |
df23fc39 | 38 | #define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK |
cf9e5a73 TH |
39 | |
40 | enum kernfs_node_flag { | |
df23fc39 TH |
41 | KERNFS_NS = 0x0020, |
42 | KERNFS_HAS_SEQ_SHOW = 0x0040, | |
43 | KERNFS_HAS_MMAP = 0x0080, | |
44 | KERNFS_LOCKDEP = 0x0100, | |
2063d608 | 45 | KERNFS_STATIC_NAME = 0x0200, |
6b0afc2a TH |
46 | KERNFS_SUICIDAL = 0x0400, |
47 | KERNFS_SUICIDED = 0x0800, | |
cf9e5a73 TH |
48 | }; |
49 | ||
324a56e1 TH |
50 | /* type-specific structures for kernfs_node union members */ |
51 | struct kernfs_elem_dir { | |
cf9e5a73 | 52 | unsigned long subdirs; |
adc5e8b5 | 53 | /* children rbtree starts here and goes through kn->rb */ |
cf9e5a73 TH |
54 | struct rb_root children; |
55 | ||
56 | /* | |
57 | * The kernfs hierarchy this directory belongs to. This fits | |
324a56e1 | 58 | * better directly in kernfs_node but is here to save space. |
cf9e5a73 TH |
59 | */ |
60 | struct kernfs_root *root; | |
61 | }; | |
62 | ||
324a56e1 TH |
63 | struct kernfs_elem_symlink { |
64 | struct kernfs_node *target_kn; | |
cf9e5a73 TH |
65 | }; |
66 | ||
324a56e1 | 67 | struct kernfs_elem_attr { |
cf9e5a73 | 68 | const struct kernfs_ops *ops; |
c525aadd | 69 | struct kernfs_open_node *open; |
cf9e5a73 TH |
70 | loff_t size; |
71 | }; | |
72 | ||
73 | /* | |
324a56e1 TH |
74 | * kernfs_node - the building block of kernfs hierarchy. Each and every |
75 | * kernfs node is represented by single kernfs_node. Most fields are | |
cf9e5a73 TH |
76 | * private to kernfs and shouldn't be accessed directly by kernfs users. |
77 | * | |
324a56e1 TH |
78 | * As long as s_count reference is held, the kernfs_node itself is |
79 | * accessible. Dereferencing elem or any other outer entity requires | |
80 | * active reference. | |
cf9e5a73 | 81 | */ |
324a56e1 | 82 | struct kernfs_node { |
adc5e8b5 TH |
83 | atomic_t count; |
84 | atomic_t active; | |
cf9e5a73 TH |
85 | #ifdef CONFIG_DEBUG_LOCK_ALLOC |
86 | struct lockdep_map dep_map; | |
87 | #endif | |
88 | /* the following two fields are published */ | |
adc5e8b5 TH |
89 | struct kernfs_node *parent; |
90 | const char *name; | |
cf9e5a73 | 91 | |
adc5e8b5 | 92 | struct rb_node rb; |
cf9e5a73 | 93 | |
adc5e8b5 | 94 | const void *ns; /* namespace tag */ |
9b0925a6 | 95 | unsigned int hash; /* ns + name hash */ |
cf9e5a73 | 96 | union { |
adc5e8b5 TH |
97 | struct kernfs_elem_dir dir; |
98 | struct kernfs_elem_symlink symlink; | |
99 | struct kernfs_elem_attr attr; | |
cf9e5a73 TH |
100 | }; |
101 | ||
102 | void *priv; | |
103 | ||
adc5e8b5 TH |
104 | unsigned short flags; |
105 | umode_t mode; | |
106 | unsigned int ino; | |
c525aadd | 107 | struct kernfs_iattrs *iattr; |
cf9e5a73 | 108 | }; |
b8441ed2 | 109 | |
80b9bbef TH |
110 | /* |
111 | * kernfs_dir_ops may be specified on kernfs_create_root() to support | |
112 | * directory manipulation syscalls. These optional callbacks are invoked | |
113 | * on the matching syscalls and can perform any kernfs operations which | |
07c7530d TH |
114 | * don't necessarily have to be the exact operation requested. An active |
115 | * reference is held for each kernfs_node parameter. | |
80b9bbef TH |
116 | */ |
117 | struct kernfs_dir_ops { | |
118 | int (*mkdir)(struct kernfs_node *parent, const char *name, | |
119 | umode_t mode); | |
120 | int (*rmdir)(struct kernfs_node *kn); | |
121 | int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent, | |
122 | const char *new_name); | |
123 | }; | |
124 | ||
ba7443bc TH |
125 | struct kernfs_root { |
126 | /* published fields */ | |
324a56e1 | 127 | struct kernfs_node *kn; |
bc755553 TH |
128 | |
129 | /* private fields, do not use outside kernfs proper */ | |
130 | struct ida ino_ida; | |
80b9bbef | 131 | struct kernfs_dir_ops *dir_ops; |
abd54f02 | 132 | wait_queue_head_t deactivate_waitq; |
ba7443bc TH |
133 | }; |
134 | ||
c525aadd | 135 | struct kernfs_open_file { |
dd8a5b03 | 136 | /* published fields */ |
324a56e1 | 137 | struct kernfs_node *kn; |
dd8a5b03 TH |
138 | struct file *file; |
139 | ||
140 | /* private fields, do not use outside kernfs proper */ | |
141 | struct mutex mutex; | |
142 | int event; | |
143 | struct list_head list; | |
144 | ||
145 | bool mmapped; | |
146 | const struct vm_operations_struct *vm_ops; | |
147 | }; | |
148 | ||
f6acf8bb TH |
149 | struct kernfs_ops { |
150 | /* | |
151 | * Read is handled by either seq_file or raw_read(). | |
152 | * | |
d19b9846 TH |
153 | * If seq_show() is present, seq_file path is active. Other seq |
154 | * operations are optional and if not implemented, the behavior is | |
155 | * equivalent to single_open(). @sf->private points to the | |
c525aadd | 156 | * associated kernfs_open_file. |
f6acf8bb TH |
157 | * |
158 | * read() is bounced through kernel buffer and a read larger than | |
159 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
160 | */ | |
161 | int (*seq_show)(struct seq_file *sf, void *v); | |
d19b9846 TH |
162 | |
163 | void *(*seq_start)(struct seq_file *sf, loff_t *ppos); | |
164 | void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos); | |
165 | void (*seq_stop)(struct seq_file *sf, void *v); | |
f6acf8bb | 166 | |
c525aadd | 167 | ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
168 | loff_t off); |
169 | ||
170 | /* | |
171 | * write() is bounced through kernel buffer and a write larger than | |
172 | * PAGE_SIZE results in partial operation of PAGE_SIZE. | |
173 | */ | |
c525aadd | 174 | ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes, |
f6acf8bb TH |
175 | loff_t off); |
176 | ||
c525aadd | 177 | int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma); |
517e64f5 TH |
178 | |
179 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
180 | struct lock_class_key lockdep_key; | |
181 | #endif | |
f6acf8bb TH |
182 | }; |
183 | ||
879f40d1 TH |
184 | #ifdef CONFIG_SYSFS |
185 | ||
df23fc39 | 186 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 | 187 | { |
df23fc39 | 188 | return kn->flags & KERNFS_TYPE_MASK; |
cf9e5a73 TH |
189 | } |
190 | ||
191 | /** | |
192 | * kernfs_enable_ns - enable namespace under a directory | |
324a56e1 | 193 | * @kn: directory of interest, should be empty |
cf9e5a73 | 194 | * |
324a56e1 TH |
195 | * This is to be called right after @kn is created to enable namespace |
196 | * under it. All children of @kn must have non-NULL namespace tags and | |
cf9e5a73 TH |
197 | * only the ones which match the super_block's tag will be visible. |
198 | */ | |
324a56e1 | 199 | static inline void kernfs_enable_ns(struct kernfs_node *kn) |
cf9e5a73 | 200 | { |
df23fc39 | 201 | WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR); |
adc5e8b5 | 202 | WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children)); |
df23fc39 | 203 | kn->flags |= KERNFS_NS; |
cf9e5a73 TH |
204 | } |
205 | ||
ac9bba03 TH |
206 | /** |
207 | * kernfs_ns_enabled - test whether namespace is enabled | |
324a56e1 | 208 | * @kn: the node to test |
ac9bba03 TH |
209 | * |
210 | * Test whether namespace filtering is enabled for the children of @ns. | |
211 | */ | |
324a56e1 | 212 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 | 213 | { |
df23fc39 | 214 | return kn->flags & KERNFS_NS; |
ac9bba03 TH |
215 | } |
216 | ||
324a56e1 TH |
217 | struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent, |
218 | const char *name, const void *ns); | |
219 | void kernfs_get(struct kernfs_node *kn); | |
220 | void kernfs_put(struct kernfs_node *kn); | |
ccf73cf3 | 221 | |
80b9bbef TH |
222 | struct kernfs_root *kernfs_create_root(struct kernfs_dir_ops *kdops, |
223 | void *priv); | |
ba7443bc TH |
224 | void kernfs_destroy_root(struct kernfs_root *root); |
225 | ||
324a56e1 | 226 | struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent, |
bb8b9d09 TH |
227 | const char *name, umode_t mode, |
228 | void *priv, const void *ns); | |
2063d608 TH |
229 | struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent, |
230 | const char *name, | |
231 | umode_t mode, loff_t size, | |
232 | const struct kernfs_ops *ops, | |
233 | void *priv, const void *ns, | |
234 | bool name_is_static, | |
235 | struct lock_class_key *key); | |
324a56e1 TH |
236 | struct kernfs_node *kernfs_create_link(struct kernfs_node *parent, |
237 | const char *name, | |
238 | struct kernfs_node *target); | |
239 | void kernfs_remove(struct kernfs_node *kn); | |
6b0afc2a TH |
240 | void kernfs_break_active_protection(struct kernfs_node *kn); |
241 | void kernfs_unbreak_active_protection(struct kernfs_node *kn); | |
242 | bool kernfs_remove_self(struct kernfs_node *kn); | |
324a56e1 | 243 | int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name, |
879f40d1 | 244 | const void *ns); |
324a56e1 | 245 | int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent, |
890ece16 | 246 | const char *new_name, const void *new_ns); |
324a56e1 TH |
247 | int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr); |
248 | void kernfs_notify(struct kernfs_node *kn); | |
879f40d1 | 249 | |
4b93dc9b TH |
250 | const void *kernfs_super_ns(struct super_block *sb); |
251 | struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
252 | struct kernfs_root *root, const void *ns); | |
253 | void kernfs_kill_sb(struct super_block *sb); | |
254 | ||
255 | void kernfs_init(void); | |
256 | ||
879f40d1 TH |
257 | #else /* CONFIG_SYSFS */ |
258 | ||
df23fc39 | 259 | static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn) |
cf9e5a73 TH |
260 | { return 0; } /* whatever */ |
261 | ||
324a56e1 | 262 | static inline void kernfs_enable_ns(struct kernfs_node *kn) { } |
cf9e5a73 | 263 | |
324a56e1 | 264 | static inline bool kernfs_ns_enabled(struct kernfs_node *kn) |
ac9bba03 TH |
265 | { return false; } |
266 | ||
324a56e1 TH |
267 | static inline struct kernfs_node * |
268 | kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name, | |
ccf73cf3 TH |
269 | const void *ns) |
270 | { return NULL; } | |
271 | ||
324a56e1 TH |
272 | static inline void kernfs_get(struct kernfs_node *kn) { } |
273 | static inline void kernfs_put(struct kernfs_node *kn) { } | |
ccf73cf3 | 274 | |
80b9bbef TH |
275 | static inline struct kernfs_root * |
276 | kernfs_create_root(struct kernfs_dir_ops *kdops, void *priv) | |
ba7443bc TH |
277 | { return ERR_PTR(-ENOSYS); } |
278 | ||
279 | static inline void kernfs_destroy_root(struct kernfs_root *root) { } | |
280 | ||
324a56e1 | 281 | static inline struct kernfs_node * |
bb8b9d09 TH |
282 | kernfs_create_dir_ns(struct kernfs_node *parent, const char *name, |
283 | umode_t mode, void *priv, const void *ns) | |
93b2b8e4 TH |
284 | { return ERR_PTR(-ENOSYS); } |
285 | ||
324a56e1 | 286 | static inline struct kernfs_node * |
2063d608 TH |
287 | __kernfs_create_file(struct kernfs_node *parent, const char *name, |
288 | umode_t mode, loff_t size, const struct kernfs_ops *ops, | |
289 | void *priv, const void *ns, bool name_is_static, | |
290 | struct lock_class_key *key) | |
496f7394 TH |
291 | { return ERR_PTR(-ENOSYS); } |
292 | ||
324a56e1 TH |
293 | static inline struct kernfs_node * |
294 | kernfs_create_link(struct kernfs_node *parent, const char *name, | |
295 | struct kernfs_node *target) | |
5d0e26bb TH |
296 | { return ERR_PTR(-ENOSYS); } |
297 | ||
324a56e1 | 298 | static inline void kernfs_remove(struct kernfs_node *kn) { } |
879f40d1 | 299 | |
6b0afc2a TH |
300 | static inline bool kernfs_remove_self(struct kernfs_node *kn) |
301 | { return false; } | |
302 | ||
324a56e1 | 303 | static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn, |
879f40d1 TH |
304 | const char *name, const void *ns) |
305 | { return -ENOSYS; } | |
306 | ||
324a56e1 TH |
307 | static inline int kernfs_rename_ns(struct kernfs_node *kn, |
308 | struct kernfs_node *new_parent, | |
890ece16 TH |
309 | const char *new_name, const void *new_ns) |
310 | { return -ENOSYS; } | |
311 | ||
324a56e1 | 312 | static inline int kernfs_setattr(struct kernfs_node *kn, |
5d60418e TH |
313 | const struct iattr *iattr) |
314 | { return -ENOSYS; } | |
315 | ||
324a56e1 | 316 | static inline void kernfs_notify(struct kernfs_node *kn) { } |
024f6471 | 317 | |
4b93dc9b TH |
318 | static inline const void *kernfs_super_ns(struct super_block *sb) |
319 | { return NULL; } | |
320 | ||
321 | static inline struct dentry * | |
322 | kernfs_mount_ns(struct file_system_type *fs_type, int flags, | |
323 | struct kernfs_root *root, const void *ns) | |
324 | { return ERR_PTR(-ENOSYS); } | |
325 | ||
326 | static inline void kernfs_kill_sb(struct super_block *sb) { } | |
327 | ||
328 | static inline void kernfs_init(void) { } | |
329 | ||
879f40d1 TH |
330 | #endif /* CONFIG_SYSFS */ |
331 | ||
324a56e1 TH |
332 | static inline struct kernfs_node * |
333 | kernfs_find_and_get(struct kernfs_node *kn, const char *name) | |
ccf73cf3 | 334 | { |
324a56e1 | 335 | return kernfs_find_and_get_ns(kn, name, NULL); |
ccf73cf3 TH |
336 | } |
337 | ||
324a56e1 | 338 | static inline struct kernfs_node * |
bb8b9d09 TH |
339 | kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode, |
340 | void *priv) | |
93b2b8e4 | 341 | { |
bb8b9d09 | 342 | return kernfs_create_dir_ns(parent, name, mode, priv, NULL); |
93b2b8e4 TH |
343 | } |
344 | ||
324a56e1 TH |
345 | static inline struct kernfs_node * |
346 | kernfs_create_file_ns(struct kernfs_node *parent, const char *name, | |
517e64f5 TH |
347 | umode_t mode, loff_t size, const struct kernfs_ops *ops, |
348 | void *priv, const void *ns) | |
349 | { | |
350 | struct lock_class_key *key = NULL; | |
351 | ||
352 | #ifdef CONFIG_DEBUG_LOCK_ALLOC | |
353 | key = (struct lock_class_key *)&ops->lockdep_key; | |
354 | #endif | |
2063d608 TH |
355 | return __kernfs_create_file(parent, name, mode, size, ops, priv, ns, |
356 | false, key); | |
517e64f5 TH |
357 | } |
358 | ||
324a56e1 TH |
359 | static inline struct kernfs_node * |
360 | kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode, | |
496f7394 TH |
361 | loff_t size, const struct kernfs_ops *ops, void *priv) |
362 | { | |
363 | return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL); | |
364 | } | |
365 | ||
324a56e1 | 366 | static inline int kernfs_remove_by_name(struct kernfs_node *parent, |
879f40d1 TH |
367 | const char *name) |
368 | { | |
369 | return kernfs_remove_by_name_ns(parent, name, NULL); | |
370 | } | |
371 | ||
4b93dc9b TH |
372 | static inline struct dentry * |
373 | kernfs_mount(struct file_system_type *fs_type, int flags, | |
374 | struct kernfs_root *root) | |
375 | { | |
376 | return kernfs_mount_ns(fs_type, flags, root, NULL); | |
377 | } | |
378 | ||
b8441ed2 | 379 | #endif /* __LINUX_KERNFS_H */ |