1
2
3
4
5
6
7#ifndef __LINUX_KERNFS_H
8#define __LINUX_KERNFS_H
9
10#include <linux/kernel.h>
11#include <linux/err.h>
12#include <linux/list.h>
13#include <linux/mutex.h>
14#include <linux/idr.h>
15#include <linux/lockdep.h>
16#include <linux/rbtree.h>
17#include <linux/atomic.h>
18#include <linux/wait.h>
19
20struct file;
21struct dentry;
22struct iattr;
23struct seq_file;
24struct vm_area_struct;
25struct super_block;
26struct file_system_type;
27
28struct kernfs_open_node;
29struct kernfs_iattrs;
30
31enum kernfs_node_type {
32 KERNFS_DIR = 0x0001,
33 KERNFS_FILE = 0x0002,
34 KERNFS_LINK = 0x0004,
35};
36
37#define KERNFS_TYPE_MASK 0x000f
38#define KERNFS_FLAG_MASK ~KERNFS_TYPE_MASK
39
40enum kernfs_node_flag {
41 KERNFS_ACTIVATED = 0x0010,
42 KERNFS_NS = 0x0020,
43 KERNFS_HAS_SEQ_SHOW = 0x0040,
44 KERNFS_HAS_MMAP = 0x0080,
45 KERNFS_LOCKDEP = 0x0100,
46 KERNFS_SUICIDAL = 0x0400,
47 KERNFS_SUICIDED = 0x0800,
48 KERNFS_EMPTY_DIR = 0x1000,
49};
50
51
52enum kernfs_root_flag {
53
54
55
56
57
58
59 KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
60
61
62
63
64
65
66
67
68
69
70 KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK = 0x0002,
71};
72
73
74struct kernfs_elem_dir {
75 unsigned long subdirs;
76
77 struct rb_root children;
78
79
80
81
82
83 struct kernfs_root *root;
84};
85
86struct kernfs_elem_symlink {
87 struct kernfs_node *target_kn;
88};
89
90struct kernfs_elem_attr {
91 const struct kernfs_ops *ops;
92 struct kernfs_open_node *open;
93 loff_t size;
94 struct kernfs_node *notify_next;
95};
96
97
98
99
100
101
102
103
104
105
106struct kernfs_node {
107 atomic_t count;
108 atomic_t active;
109#ifdef CONFIG_DEBUG_LOCK_ALLOC
110 struct lockdep_map dep_map;
111#endif
112
113
114
115
116
117
118 struct kernfs_node *parent;
119 const char *name;
120
121 struct rb_node rb;
122
123 const void *ns;
124 unsigned int hash;
125 union {
126 struct kernfs_elem_dir dir;
127 struct kernfs_elem_symlink symlink;
128 struct kernfs_elem_attr attr;
129 };
130
131 void *priv;
132
133 unsigned short flags;
134 umode_t mode;
135 unsigned int ino;
136 struct kernfs_iattrs *iattr;
137};
138
139
140
141
142
143
144
145
146struct kernfs_syscall_ops {
147 int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
148 int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
149
150 int (*mkdir)(struct kernfs_node *parent, const char *name,
151 umode_t mode);
152 int (*rmdir)(struct kernfs_node *kn);
153 int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent,
154 const char *new_name);
155 int (*show_path)(struct seq_file *sf, struct kernfs_node *kn,
156 struct kernfs_root *root);
157};
158
159struct kernfs_root {
160
161 struct kernfs_node *kn;
162 unsigned int flags;
163
164
165 struct ida ino_ida;
166 struct kernfs_syscall_ops *syscall_ops;
167
168
169 struct list_head supers;
170
171 wait_queue_head_t deactivate_waitq;
172};
173
174struct kernfs_open_file {
175
176 struct kernfs_node *kn;
177 struct file *file;
178 void *priv;
179
180
181 struct mutex mutex;
182 int event;
183 struct list_head list;
184 char *prealloc_buf;
185
186 size_t atomic_write_len;
187 bool mmapped;
188 const struct vm_operations_struct *vm_ops;
189};
190
191struct kernfs_ops {
192
193
194
195
196
197
198
199
200
201
202
203 int (*seq_show)(struct seq_file *sf, void *v);
204
205 void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
206 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
207 void (*seq_stop)(struct seq_file *sf, void *v);
208
209 ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes,
210 loff_t off);
211
212
213
214
215
216
217
218
219 size_t atomic_write_len;
220
221
222
223
224
225
226 bool prealloc;
227 ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
228 loff_t off);
229
230 int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma);
231
232#ifdef CONFIG_DEBUG_LOCK_ALLOC
233 struct lock_class_key lockdep_key;
234#endif
235};
236
237#ifdef CONFIG_KERNFS
238
239static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
240{
241 return kn->flags & KERNFS_TYPE_MASK;
242}
243
244
245
246
247
248
249
250
251
252static inline void kernfs_enable_ns(struct kernfs_node *kn)
253{
254 WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
255 WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
256 kn->flags |= KERNFS_NS;
257}
258
259
260
261
262
263
264
265static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
266{
267 return kn->flags & KERNFS_NS;
268}
269
270int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
271size_t kernfs_path_len(struct kernfs_node *kn);
272int kernfs_path_from_node(struct kernfs_node *root_kn, struct kernfs_node *kn,
273 char *buf, size_t buflen);
274char *kernfs_path(struct kernfs_node *kn, char *buf, size_t buflen);
275void pr_cont_kernfs_name(struct kernfs_node *kn);
276void pr_cont_kernfs_path(struct kernfs_node *kn);
277struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
278struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
279 const char *name, const void *ns);
280struct kernfs_node *kernfs_walk_and_get_ns(struct kernfs_node *parent,
281 const char *path, const void *ns);
282void kernfs_get(struct kernfs_node *kn);
283void kernfs_put(struct kernfs_node *kn);
284
285struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
286struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
287struct inode *kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn);
288
289struct dentry *kernfs_node_dentry(struct kernfs_node *kn,
290 struct super_block *sb);
291struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
292 unsigned int flags, void *priv);
293void kernfs_destroy_root(struct kernfs_root *root);
294
295struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
296 const char *name, umode_t mode,
297 void *priv, const void *ns);
298struct kernfs_node *kernfs_create_empty_dir(struct kernfs_node *parent,
299 const char *name);
300struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
301 const char *name,
302 umode_t mode, loff_t size,
303 const struct kernfs_ops *ops,
304 void *priv, const void *ns,
305 struct lock_class_key *key);
306struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
307 const char *name,
308 struct kernfs_node *target);
309void kernfs_activate(struct kernfs_node *kn);
310void kernfs_remove(struct kernfs_node *kn);
311void kernfs_break_active_protection(struct kernfs_node *kn);
312void kernfs_unbreak_active_protection(struct kernfs_node *kn);
313bool kernfs_remove_self(struct kernfs_node *kn);
314int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
315 const void *ns);
316int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
317 const char *new_name, const void *new_ns);
318int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
319void kernfs_notify(struct kernfs_node *kn);
320
321const void *kernfs_super_ns(struct super_block *sb);
322struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
323 struct kernfs_root *root, unsigned long magic,
324 bool *new_sb_created, const void *ns);
325void kernfs_kill_sb(struct super_block *sb);
326struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns);
327
328void kernfs_init(void);
329
330#else
331
332static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
333{ return 0; }
334
335static inline void kernfs_enable_ns(struct kernfs_node *kn) { }
336
337static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
338{ return false; }
339
340static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
341{ return -ENOSYS; }
342
343static inline size_t kernfs_path_len(struct kernfs_node *kn)
344{ return 0; }
345
346static inline char *kernfs_path(struct kernfs_node *kn, char *buf,
347 size_t buflen)
348{ return NULL; }
349
350static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
351static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }
352
353static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
354{ return NULL; }
355
356static inline struct kernfs_node *
357kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
358 const void *ns)
359{ return NULL; }
360static inline struct kernfs_node *
361kernfs_walk_and_get_ns(struct kernfs_node *parent, const char *path,
362 const void *ns)
363{ return NULL; }
364
365static inline void kernfs_get(struct kernfs_node *kn) { }
366static inline void kernfs_put(struct kernfs_node *kn) { }
367
368static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
369{ return NULL; }
370
371static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
372{ return NULL; }
373
374static inline struct inode *
375kernfs_get_inode(struct super_block *sb, struct kernfs_node *kn)
376{ return NULL; }
377
378static inline struct kernfs_root *
379kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
380 void *priv)
381{ return ERR_PTR(-ENOSYS); }
382
383static inline void kernfs_destroy_root(struct kernfs_root *root) { }
384
385static inline struct kernfs_node *
386kernfs_create_dir_ns(struct kernfs_node *parent, const char *name,
387 umode_t mode, void *priv, const void *ns)
388{ return ERR_PTR(-ENOSYS); }
389
390static inline struct kernfs_node *
391__kernfs_create_file(struct kernfs_node *parent, const char *name,
392 umode_t mode, loff_t size, const struct kernfs_ops *ops,
393 void *priv, const void *ns, struct lock_class_key *key)
394{ return ERR_PTR(-ENOSYS); }
395
396static inline struct kernfs_node *
397kernfs_create_link(struct kernfs_node *parent, const char *name,
398 struct kernfs_node *target)
399{ return ERR_PTR(-ENOSYS); }
400
401static inline void kernfs_activate(struct kernfs_node *kn) { }
402
403static inline void kernfs_remove(struct kernfs_node *kn) { }
404
405static inline bool kernfs_remove_self(struct kernfs_node *kn)
406{ return false; }
407
408static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
409 const char *name, const void *ns)
410{ return -ENOSYS; }
411
412static inline int kernfs_rename_ns(struct kernfs_node *kn,
413 struct kernfs_node *new_parent,
414 const char *new_name, const void *new_ns)
415{ return -ENOSYS; }
416
417static inline int kernfs_setattr(struct kernfs_node *kn,
418 const struct iattr *iattr)
419{ return -ENOSYS; }
420
421static inline void kernfs_notify(struct kernfs_node *kn) { }
422
423static inline const void *kernfs_super_ns(struct super_block *sb)
424{ return NULL; }
425
426static inline struct dentry *
427kernfs_mount_ns(struct file_system_type *fs_type, int flags,
428 struct kernfs_root *root, unsigned long magic,
429 bool *new_sb_created, const void *ns)
430{ return ERR_PTR(-ENOSYS); }
431
432static inline void kernfs_kill_sb(struct super_block *sb) { }
433
434static inline void kernfs_init(void) { }
435
436#endif
437
438static inline struct kernfs_node *
439kernfs_find_and_get(struct kernfs_node *kn, const char *name)
440{
441 return kernfs_find_and_get_ns(kn, name, NULL);
442}
443
444static inline struct kernfs_node *
445kernfs_walk_and_get(struct kernfs_node *kn, const char *path)
446{
447 return kernfs_walk_and_get_ns(kn, path, NULL);
448}
449
450static inline struct kernfs_node *
451kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode,
452 void *priv)
453{
454 return kernfs_create_dir_ns(parent, name, mode, priv, NULL);
455}
456
457static inline struct kernfs_node *
458kernfs_create_file_ns(struct kernfs_node *parent, const char *name,
459 umode_t mode, loff_t size, const struct kernfs_ops *ops,
460 void *priv, const void *ns)
461{
462 struct lock_class_key *key = NULL;
463
464#ifdef CONFIG_DEBUG_LOCK_ALLOC
465 key = (struct lock_class_key *)&ops->lockdep_key;
466#endif
467 return __kernfs_create_file(parent, name, mode, size, ops, priv, ns,
468 key);
469}
470
471static inline struct kernfs_node *
472kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode,
473 loff_t size, const struct kernfs_ops *ops, void *priv)
474{
475 return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
476}
477
478static inline int kernfs_remove_by_name(struct kernfs_node *parent,
479 const char *name)
480{
481 return kernfs_remove_by_name_ns(parent, name, NULL);
482}
483
484static inline int kernfs_rename(struct kernfs_node *kn,
485 struct kernfs_node *new_parent,
486 const char *new_name)
487{
488 return kernfs_rename_ns(kn, new_parent, new_name, NULL);
489}
490
491static inline struct dentry *
492kernfs_mount(struct file_system_type *fs_type, int flags,
493 struct kernfs_root *root, unsigned long magic,
494 bool *new_sb_created)
495{
496 return kernfs_mount_ns(fs_type, flags, root,
497 magic, new_sb_created, NULL);
498}
499
500#endif
501