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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};
49
50
51enum kernfs_root_flag {
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57
58 KERNFS_ROOT_CREATE_DEACTIVATED = 0x0001,
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68
69 KERNFS_ROOT_EXTRA_OPEN_PERM_CHECK = 0x0002,
70};
71
72
73struct kernfs_elem_dir {
74 unsigned long subdirs;
75
76 struct rb_root children;
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81
82 struct kernfs_root *root;
83};
84
85struct kernfs_elem_symlink {
86 struct kernfs_node *target_kn;
87};
88
89struct kernfs_elem_attr {
90 const struct kernfs_ops *ops;
91 struct kernfs_open_node *open;
92 loff_t size;
93 struct kernfs_node *notify_next;
94};
95
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103
104
105struct kernfs_node {
106 atomic_t count;
107 atomic_t active;
108#ifdef CONFIG_DEBUG_LOCK_ALLOC
109 struct lockdep_map dep_map;
110#endif
111
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115
116
117 struct kernfs_node *parent;
118 const char *name;
119
120 struct rb_node rb;
121
122 const void *ns;
123 unsigned int hash;
124 union {
125 struct kernfs_elem_dir dir;
126 struct kernfs_elem_symlink symlink;
127 struct kernfs_elem_attr attr;
128 };
129
130 void *priv;
131
132 unsigned short flags;
133 umode_t mode;
134 unsigned int ino;
135 struct kernfs_iattrs *iattr;
136};
137
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143
144
145struct kernfs_syscall_ops {
146 int (*remount_fs)(struct kernfs_root *root, int *flags, char *data);
147 int (*show_options)(struct seq_file *sf, struct kernfs_root *root);
148
149 int (*mkdir)(struct kernfs_node *parent, const char *name,
150 umode_t mode);
151 int (*rmdir)(struct kernfs_node *kn);
152 int (*rename)(struct kernfs_node *kn, struct kernfs_node *new_parent,
153 const char *new_name);
154};
155
156struct kernfs_root {
157
158 struct kernfs_node *kn;
159 unsigned int flags;
160
161
162 struct ida ino_ida;
163 struct kernfs_syscall_ops *syscall_ops;
164
165
166 struct list_head supers;
167
168 wait_queue_head_t deactivate_waitq;
169};
170
171struct kernfs_open_file {
172
173 struct kernfs_node *kn;
174 struct file *file;
175 void *priv;
176
177
178 struct mutex mutex;
179 int event;
180 struct list_head list;
181 char *prealloc_buf;
182
183 size_t atomic_write_len;
184 bool mmapped;
185 const struct vm_operations_struct *vm_ops;
186};
187
188struct kernfs_ops {
189
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199
200 int (*seq_show)(struct seq_file *sf, void *v);
201
202 void *(*seq_start)(struct seq_file *sf, loff_t *ppos);
203 void *(*seq_next)(struct seq_file *sf, void *v, loff_t *ppos);
204 void (*seq_stop)(struct seq_file *sf, void *v);
205
206 ssize_t (*read)(struct kernfs_open_file *of, char *buf, size_t bytes,
207 loff_t off);
208
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215
216 size_t atomic_write_len;
217
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221
222
223 bool prealloc;
224 ssize_t (*write)(struct kernfs_open_file *of, char *buf, size_t bytes,
225 loff_t off);
226
227 int (*mmap)(struct kernfs_open_file *of, struct vm_area_struct *vma);
228
229#ifdef CONFIG_DEBUG_LOCK_ALLOC
230 struct lock_class_key lockdep_key;
231#endif
232};
233
234#ifdef CONFIG_KERNFS
235
236static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
237{
238 return kn->flags & KERNFS_TYPE_MASK;
239}
240
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247
248
249static inline void kernfs_enable_ns(struct kernfs_node *kn)
250{
251 WARN_ON_ONCE(kernfs_type(kn) != KERNFS_DIR);
252 WARN_ON_ONCE(!RB_EMPTY_ROOT(&kn->dir.children));
253 kn->flags |= KERNFS_NS;
254}
255
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259
260
261
262static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
263{
264 return kn->flags & KERNFS_NS;
265}
266
267int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen);
268char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
269 size_t buflen);
270void pr_cont_kernfs_name(struct kernfs_node *kn);
271void pr_cont_kernfs_path(struct kernfs_node *kn);
272struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn);
273struct kernfs_node *kernfs_find_and_get_ns(struct kernfs_node *parent,
274 const char *name, const void *ns);
275void kernfs_get(struct kernfs_node *kn);
276void kernfs_put(struct kernfs_node *kn);
277
278struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry);
279struct kernfs_root *kernfs_root_from_sb(struct super_block *sb);
280
281struct kernfs_root *kernfs_create_root(struct kernfs_syscall_ops *scops,
282 unsigned int flags, void *priv);
283void kernfs_destroy_root(struct kernfs_root *root);
284
285struct kernfs_node *kernfs_create_dir_ns(struct kernfs_node *parent,
286 const char *name, umode_t mode,
287 void *priv, const void *ns);
288struct kernfs_node *__kernfs_create_file(struct kernfs_node *parent,
289 const char *name,
290 umode_t mode, loff_t size,
291 const struct kernfs_ops *ops,
292 void *priv, const void *ns,
293 struct lock_class_key *key);
294struct kernfs_node *kernfs_create_link(struct kernfs_node *parent,
295 const char *name,
296 struct kernfs_node *target);
297void kernfs_activate(struct kernfs_node *kn);
298void kernfs_remove(struct kernfs_node *kn);
299void kernfs_break_active_protection(struct kernfs_node *kn);
300void kernfs_unbreak_active_protection(struct kernfs_node *kn);
301bool kernfs_remove_self(struct kernfs_node *kn);
302int kernfs_remove_by_name_ns(struct kernfs_node *parent, const char *name,
303 const void *ns);
304int kernfs_rename_ns(struct kernfs_node *kn, struct kernfs_node *new_parent,
305 const char *new_name, const void *new_ns);
306int kernfs_setattr(struct kernfs_node *kn, const struct iattr *iattr);
307void kernfs_notify(struct kernfs_node *kn);
308
309const void *kernfs_super_ns(struct super_block *sb);
310struct dentry *kernfs_mount_ns(struct file_system_type *fs_type, int flags,
311 struct kernfs_root *root, unsigned long magic,
312 bool *new_sb_created, const void *ns);
313void kernfs_kill_sb(struct super_block *sb);
314struct super_block *kernfs_pin_sb(struct kernfs_root *root, const void *ns);
315
316void kernfs_init(void);
317
318#else
319
320static inline enum kernfs_node_type kernfs_type(struct kernfs_node *kn)
321{ return 0; }
322
323static inline void kernfs_enable_ns(struct kernfs_node *kn) { }
324
325static inline bool kernfs_ns_enabled(struct kernfs_node *kn)
326{ return false; }
327
328static inline int kernfs_name(struct kernfs_node *kn, char *buf, size_t buflen)
329{ return -ENOSYS; }
330
331static inline char * __must_check kernfs_path(struct kernfs_node *kn, char *buf,
332 size_t buflen)
333{ return NULL; }
334
335static inline void pr_cont_kernfs_name(struct kernfs_node *kn) { }
336static inline void pr_cont_kernfs_path(struct kernfs_node *kn) { }
337
338static inline struct kernfs_node *kernfs_get_parent(struct kernfs_node *kn)
339{ return NULL; }
340
341static inline struct kernfs_node *
342kernfs_find_and_get_ns(struct kernfs_node *parent, const char *name,
343 const void *ns)
344{ return NULL; }
345
346static inline void kernfs_get(struct kernfs_node *kn) { }
347static inline void kernfs_put(struct kernfs_node *kn) { }
348
349static inline struct kernfs_node *kernfs_node_from_dentry(struct dentry *dentry)
350{ return NULL; }
351
352static inline struct kernfs_root *kernfs_root_from_sb(struct super_block *sb)
353{ return NULL; }
354
355static inline struct kernfs_root *
356kernfs_create_root(struct kernfs_syscall_ops *scops, unsigned int flags,
357 void *priv)
358{ return ERR_PTR(-ENOSYS); }
359
360static inline void kernfs_destroy_root(struct kernfs_root *root) { }
361
362static inline struct kernfs_node *
363kernfs_create_dir_ns(struct kernfs_node *parent, const char *name,
364 umode_t mode, void *priv, const void *ns)
365{ return ERR_PTR(-ENOSYS); }
366
367static inline struct kernfs_node *
368__kernfs_create_file(struct kernfs_node *parent, const char *name,
369 umode_t mode, loff_t size, const struct kernfs_ops *ops,
370 void *priv, const void *ns, struct lock_class_key *key)
371{ return ERR_PTR(-ENOSYS); }
372
373static inline struct kernfs_node *
374kernfs_create_link(struct kernfs_node *parent, const char *name,
375 struct kernfs_node *target)
376{ return ERR_PTR(-ENOSYS); }
377
378static inline void kernfs_activate(struct kernfs_node *kn) { }
379
380static inline void kernfs_remove(struct kernfs_node *kn) { }
381
382static inline bool kernfs_remove_self(struct kernfs_node *kn)
383{ return false; }
384
385static inline int kernfs_remove_by_name_ns(struct kernfs_node *kn,
386 const char *name, const void *ns)
387{ return -ENOSYS; }
388
389static inline int kernfs_rename_ns(struct kernfs_node *kn,
390 struct kernfs_node *new_parent,
391 const char *new_name, const void *new_ns)
392{ return -ENOSYS; }
393
394static inline int kernfs_setattr(struct kernfs_node *kn,
395 const struct iattr *iattr)
396{ return -ENOSYS; }
397
398static inline void kernfs_notify(struct kernfs_node *kn) { }
399
400static inline const void *kernfs_super_ns(struct super_block *sb)
401{ return NULL; }
402
403static inline struct dentry *
404kernfs_mount_ns(struct file_system_type *fs_type, int flags,
405 struct kernfs_root *root, unsigned long magic,
406 bool *new_sb_created, const void *ns)
407{ return ERR_PTR(-ENOSYS); }
408
409static inline void kernfs_kill_sb(struct super_block *sb) { }
410
411static inline void kernfs_init(void) { }
412
413#endif
414
415static inline struct kernfs_node *
416kernfs_find_and_get(struct kernfs_node *kn, const char *name)
417{
418 return kernfs_find_and_get_ns(kn, name, NULL);
419}
420
421static inline struct kernfs_node *
422kernfs_create_dir(struct kernfs_node *parent, const char *name, umode_t mode,
423 void *priv)
424{
425 return kernfs_create_dir_ns(parent, name, mode, priv, NULL);
426}
427
428static inline struct kernfs_node *
429kernfs_create_file_ns(struct kernfs_node *parent, const char *name,
430 umode_t mode, loff_t size, const struct kernfs_ops *ops,
431 void *priv, const void *ns)
432{
433 struct lock_class_key *key = NULL;
434
435#ifdef CONFIG_DEBUG_LOCK_ALLOC
436 key = (struct lock_class_key *)&ops->lockdep_key;
437#endif
438 return __kernfs_create_file(parent, name, mode, size, ops, priv, ns,
439 key);
440}
441
442static inline struct kernfs_node *
443kernfs_create_file(struct kernfs_node *parent, const char *name, umode_t mode,
444 loff_t size, const struct kernfs_ops *ops, void *priv)
445{
446 return kernfs_create_file_ns(parent, name, mode, size, ops, priv, NULL);
447}
448
449static inline int kernfs_remove_by_name(struct kernfs_node *parent,
450 const char *name)
451{
452 return kernfs_remove_by_name_ns(parent, name, NULL);
453}
454
455static inline int kernfs_rename(struct kernfs_node *kn,
456 struct kernfs_node *new_parent,
457 const char *new_name)
458{
459 return kernfs_rename_ns(kn, new_parent, new_name, NULL);
460}
461
462static inline struct dentry *
463kernfs_mount(struct file_system_type *fs_type, int flags,
464 struct kernfs_root *root, unsigned long magic,
465 bool *new_sb_created)
466{
467 return kernfs_mount_ns(fs_type, flags, root,
468 magic, new_sb_created, NULL);
469}
470
471#endif
472