include/linux/sysfs.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 /*
   3  * sysfs.h - definitions for the device driver filesystem
   4  *
   5  * Copyright (c) 2001,2002 Patrick Mochel
   6  * Copyright (c) 2004 Silicon Graphics, Inc.
   7  * Copyright (c) 2007 SUSE Linux Products GmbH
   8  * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
   9  *
  10  * Please see Documentation/filesystems/sysfs.txt for more information.
  11  */
  12
  13 #ifndef _SYSFS_H_
  14 #define _SYSFS_H_
  15
  16 #include <linux/kernfs.h>
  17 #include <linux/compiler.h>
  18 #include <linux/errno.h>
  19 #include <linux/list.h>
  20 #include <linux/lockdep.h>
  21 #include <linux/kobject_ns.h>
  22 #include <linux/stat.h>
  23 #include <linux/atomic.h>
  24
  25 struct kobject;
  26 struct module;
  27 struct bin_attribute;
  28 enum kobj_ns_type;
  29
  30 struct attribute {
  31         const char              *name;
  32         umode_t                 mode;
  33 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  34         bool                    ignore_lockdep:1;
  35         struct lock_class_key   *key;
  36         struct lock_class_key   skey;
  37 #endif
  38 };
  39
  40 /**
  41  *      sysfs_attr_init - initialize a dynamically allocated sysfs attribute
  42  *      @attr: struct attribute to initialize
  43  *
  44  *      Initialize a dynamically allocated struct attribute so we can
  45  *      make lockdep happy.  This is a new requirement for attributes
  46  *      and initially this is only needed when lockdep is enabled.
  47  *      Lockdep gives a nice error when your attribute is added to
  48  *      sysfs if you don't have this.
  49  */
  50 #ifdef CONFIG_DEBUG_LOCK_ALLOC
  51 #define sysfs_attr_init(attr)                           \
  52 do {                                                    \
  53         static struct lock_class_key __key;             \
  54                                                         \
  55         (attr)->key = &__key;                           \
  56 } while (0)
  57 #else
  58 #define sysfs_attr_init(attr) do {} while (0)
  59 #endif
  60
  61 /**
  62  * struct attribute_group - data structure used to declare an attribute group.
  63  * @name:       Optional: Attribute group name
  64  *              If specified, the attribute group will be created in
  65  *              a new subdirectory with this name.
  66  * @is_visible: Optional: Function to return permissions associated with an
  67  *              attribute of the group. Will be called repeatedly for each
  68  *              non-binary attribute in the group. Only read/write
  69  *              permissions as well as SYSFS_PREALLOC are accepted. Must
  70  *              return 0 if an attribute is not visible. The returned value
  71  *              will replace static permissions defined in struct attribute.
  72  * @is_bin_visible:
  73  *              Optional: Function to return permissions associated with a
  74  *              binary attribute of the group. Will be called repeatedly
  75  *              for each binary attribute in the group. Only read/write
  76  *              permissions as well as SYSFS_PREALLOC are accepted. Must
  77  *              return 0 if a binary attribute is not visible. The returned
  78  *              value will replace static permissions defined in
  79  *              struct bin_attribute.
  80  * @attrs:      Pointer to NULL terminated list of attributes.
  81  * @bin_attrs:  Pointer to NULL terminated list of binary attributes.
  82  *              Either attrs or bin_attrs or both must be provided.
  83  */
  84 struct attribute_group {
  85         const char              *name;
  86         umode_t                 (*is_visible)(struct kobject *,
  87                                               struct attribute *, int);
  88         umode_t                 (*is_bin_visible)(struct kobject *,
  89                                                   struct bin_attribute *, int);
  90         struct attribute        **attrs;
  91         struct bin_attribute    **bin_attrs;
  92 };
  93
  94 /**
  95  * Use these macros to make defining attributes easier. See include/linux/device.h
  96  * for examples..
  97  */
  98
  99 #define SYSFS_PREALLOC 010000
 100
 101 #define __ATTR(_name, _mode, _show, _store) {                           \
 102         .attr = {.name = __stringify(_name),                            \
 103                  .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },             \
 104         .show   = _show,                                                \
 105         .store  = _store,                                               \
 106 }
 107
 108 #define __ATTR_PREALLOC(_name, _mode, _show, _store) {                  \
 109         .attr = {.name = __stringify(_name),                            \
 110                  .mode = SYSFS_PREALLOC | VERIFY_OCTAL_PERMISSIONS(_mode) },\
 111         .show   = _show,                                                \
 112         .store  = _store,                                               \
 113 }
 114
 115 #define __ATTR_RO(_name) {                                              \
 116         .attr   = { .name = __stringify(_name), .mode = S_IRUGO },      \
 117         .show   = _name##_show,                                         \
 118 }
 119
 120 #define __ATTR_WO(_name) {                                              \
 121         .attr   = { .name = __stringify(_name), .mode = S_IWUSR },      \
 122         .store  = _name##_store,                                        \
 123 }
 124
 125 #define __ATTR_RW(_name) __ATTR(_name, (S_IWUSR | S_IRUGO),             \
 126                          _name##_show, _name##_store)
 127
 128 #define __ATTR_NULL { .attr = { .name = NULL } }
 129
 130 #ifdef CONFIG_DEBUG_LOCK_ALLOC
 131 #define __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) {    \
 132         .attr = {.name = __stringify(_name), .mode = _mode,     \
 133                         .ignore_lockdep = true },               \
 134         .show           = _show,                                \
 135         .store          = _store,                               \
 136 }
 137 #else
 138 #define __ATTR_IGNORE_LOCKDEP   __ATTR
 139 #endif
 140
 141 #define __ATTRIBUTE_GROUPS(_name)                               \
 142 static const struct attribute_group *_name##_groups[] = {       \
 143         &_name##_group,                                         \
 144         NULL,                                                   \
 145 }
 146
 147 #define ATTRIBUTE_GROUPS(_name)                                 \
 148 static const struct attribute_group _name##_group = {           \
 149         .attrs = _name##_attrs,                                 \
 150 };                                                              \
 151 __ATTRIBUTE_GROUPS(_name)
 152
 153 struct file;
 154 struct vm_area_struct;
 155
 156 struct bin_attribute {
 157         struct attribute        attr;
 158         size_t                  size;
 159         void                    *private;
 160         ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *,
 161                         char *, loff_t, size_t);
 162         ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *,
 163                          char *, loff_t, size_t);
 164         int (*mmap)(struct file *, struct kobject *, struct bin_attribute *attr,
 165                     struct vm_area_struct *vma);
 166 };
 167
 168 /**
 169  *      sysfs_bin_attr_init - initialize a dynamically allocated bin_attribute
 170  *      @attr: struct bin_attribute to initialize
 171  *
 172  *      Initialize a dynamically allocated struct bin_attribute so we
 173  *      can make lockdep happy.  This is a new requirement for
 174  *      attributes and initially this is only needed when lockdep is
 175  *      enabled.  Lockdep gives a nice error when your attribute is
 176  *      added to sysfs if you don't have this.
 177  */
 178 #define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)
 179
 180 /* macros to create static binary attributes easier */
 181 #define __BIN_ATTR(_name, _mode, _read, _write, _size) {                \
 182         .attr = { .name = __stringify(_name), .mode = _mode },          \
 183         .read   = _read,                                                \
 184         .write  = _write,                                               \
 185         .size   = _size,                                                \
 186 }
 187
 188 #define __BIN_ATTR_RO(_name, _size) {                                   \
 189         .attr   = { .name = __stringify(_name), .mode = S_IRUGO },      \
 190         .read   = _name##_read,                                         \
 191         .size   = _size,                                                \
 192 }
 193
 194 #define __BIN_ATTR_RW(_name, _size) __BIN_ATTR(_name,                   \
 195                                    (S_IWUSR | S_IRUGO), _name##_read,   \
 196                                    _name##_write, _size)
 197
 198 #define __BIN_ATTR_NULL __ATTR_NULL
 199
 200 #define BIN_ATTR(_name, _mode, _read, _write, _size)                    \
 201 struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read, \
 202                                         _write, _size)
 203
 204 #define BIN_ATTR_RO(_name, _size)                                       \
 205 struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)
 206
 207 #define BIN_ATTR_RW(_name, _size)                                       \
 208 struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)
 209
 210 struct sysfs_ops {
 211         ssize_t (*show)(struct kobject *, struct attribute *, char *);
 212         ssize_t (*store)(struct kobject *, struct attribute *, const char *, size_t);
 213 };
 214
 215 #ifdef CONFIG_SYSFS
 216
 217 int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);
 218 void sysfs_remove_dir(struct kobject *kobj);
 219 int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
 220                                      const void *new_ns);
 221 int __must_check sysfs_move_dir_ns(struct kobject *kobj,
 222                                    struct kobject *new_parent_kobj,
 223                                    const void *new_ns);
 224 int __must_check sysfs_create_mount_point(struct kobject *parent_kobj,
 225                                           const char *name);
 226 void sysfs_remove_mount_point(struct kobject *parent_kobj,
 227                               const char *name);
 228
 229 int __must_check sysfs_create_file_ns(struct kobject *kobj,
 230                                       const struct attribute *attr,
 231                                       const void *ns);
 232 int __must_check sysfs_create_files(struct kobject *kobj,
 233                                    const struct attribute **attr);
 234 int __must_check sysfs_chmod_file(struct kobject *kobj,
 235                                   const struct attribute *attr, umode_t mode);
 236 void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
 237                           const void *ns);
 238 bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr);
 239 void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);
 240
 241 int __must_check sysfs_create_bin_file(struct kobject *kobj,
 242                                        const struct bin_attribute *attr);
 243 void sysfs_remove_bin_file(struct kobject *kobj,
 244                            const struct bin_attribute *attr);
 245
 246 int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
 247                                    const char *name);
 248 int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
 249                                           struct kobject *target,
 250                                           const char *name);
 251 void sysfs_remove_link(struct kobject *kobj, const char *name);
 252
 253 int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,
 254                          const char *old_name, const char *new_name,
 255                          const void *new_ns);
 256
 257 void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
 258                         const char *name);
 259
 260 int __must_check sysfs_create_group(struct kobject *kobj,
 261                                     const struct attribute_group *grp);
 262 int __must_check sysfs_create_groups(struct kobject *kobj,
 263                                      const struct attribute_group **groups);
 264 int sysfs_update_group(struct kobject *kobj,
 265                        const struct attribute_group *grp);
 266 void sysfs_remove_group(struct kobject *kobj,
 267                         const struct attribute_group *grp);
 268 void sysfs_remove_groups(struct kobject *kobj,
 269                          const struct attribute_group **groups);
 270 int sysfs_add_file_to_group(struct kobject *kobj,
 271                         const struct attribute *attr, const char *group);
 272 void sysfs_remove_file_from_group(struct kobject *kobj,
 273                         const struct attribute *attr, const char *group);
 274 int sysfs_merge_group(struct kobject *kobj,
 275                        const struct attribute_group *grp);
 276 void sysfs_unmerge_group(struct kobject *kobj,
 277                        const struct attribute_group *grp);
 278 int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
 279                             struct kobject *target, const char *link_name);
 280 void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
 281                                   const char *link_name);
 282 int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
 283                                       struct kobject *target_kobj,
 284                                       const char *target_name);
 285
 286 void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);
 287
 288 int __must_check sysfs_init(void);
 289
 290 static inline void sysfs_enable_ns(struct kernfs_node *kn)
 291 {
 292         return kernfs_enable_ns(kn);
 293 }
 294
 295 #else /* CONFIG_SYSFS */
 296
 297 static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
 298 {
 299         return 0;
 300 }
 301
 302 static inline void sysfs_remove_dir(struct kobject *kobj)
 303 {
 304 }
 305
 306 static inline int sysfs_rename_dir_ns(struct kobject *kobj,
 307                                       const char *new_name, const void *new_ns)
 308 {
 309         return 0;
 310 }
 311
 312 static inline int sysfs_move_dir_ns(struct kobject *kobj,
 313                                     struct kobject *new_parent_kobj,
 314                                     const void *new_ns)
 315 {
 316         return 0;
 317 }
 318
 319 static inline int sysfs_create_mount_point(struct kobject *parent_kobj,
 320                                            const char *name)
 321 {
 322         return 0;
 323 }
 324
 325 static inline void sysfs_remove_mount_point(struct kobject *parent_kobj,
 326                                             const char *name)
 327 {
 328 }
 329
 330 static inline int sysfs_create_file_ns(struct kobject *kobj,
 331                                        const struct attribute *attr,
 332                                        const void *ns)
 333 {
 334         return 0;
 335 }
 336
 337 static inline int sysfs_create_files(struct kobject *kobj,
 338                                     const struct attribute **attr)
 339 {
 340         return 0;
 341 }
 342
 343 static inline int sysfs_chmod_file(struct kobject *kobj,
 344                                    const struct attribute *attr, umode_t mode)
 345 {
 346         return 0;
 347 }
 348
 349 static inline void sysfs_remove_file_ns(struct kobject *kobj,
 350                                         const struct attribute *attr,
 351                                         const void *ns)
 352 {
 353 }
 354
 355 static inline bool sysfs_remove_file_self(struct kobject *kobj,
 356                                           const struct attribute *attr)
 357 {
 358         return false;
 359 }
 360
 361 static inline void sysfs_remove_files(struct kobject *kobj,
 362                                      const struct attribute **attr)
 363 {
 364 }
 365
 366 static inline int sysfs_create_bin_file(struct kobject *kobj,
 367                                         const struct bin_attribute *attr)
 368 {
 369         return 0;
 370 }
 371
 372 static inline void sysfs_remove_bin_file(struct kobject *kobj,
 373                                          const struct bin_attribute *attr)
 374 {
 375 }
 376
 377 static inline int sysfs_create_link(struct kobject *kobj,
 378                                     struct kobject *target, const char *name)
 379 {
 380         return 0;
 381 }
 382
 383 static inline int sysfs_create_link_nowarn(struct kobject *kobj,
 384                                            struct kobject *target,
 385                                            const char *name)
 386 {
 387         return 0;
 388 }
 389
 390 static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
 391 {
 392 }
 393
 394 static inline int sysfs_rename_link_ns(struct kobject *k, struct kobject *t,
 395                                        const char *old_name,
 396                                        const char *new_name, const void *ns)
 397 {
 398         return 0;
 399 }
 400
 401 static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
 402                                      const char *name)
 403 {
 404 }
 405
 406 static inline int sysfs_create_group(struct kobject *kobj,
 407                                      const struct attribute_group *grp)
 408 {
 409         return 0;
 410 }
 411
 412 static inline int sysfs_create_groups(struct kobject *kobj,
 413                                       const struct attribute_group **groups)
 414 {
 415         return 0;
 416 }
 417
 418 static inline int sysfs_update_group(struct kobject *kobj,
 419                                 const struct attribute_group *grp)
 420 {
 421         return 0;
 422 }
 423
 424 static inline void sysfs_remove_group(struct kobject *kobj,
 425                                       const struct attribute_group *grp)
 426 {
 427 }
 428
 429 static inline void sysfs_remove_groups(struct kobject *kobj,
 430                                        const struct attribute_group **groups)
 431 {
 432 }
 433
 434 static inline int sysfs_add_file_to_group(struct kobject *kobj,
 435                 const struct attribute *attr, const char *group)
 436 {
 437         return 0;
 438 }
 439
 440 static inline void sysfs_remove_file_from_group(struct kobject *kobj,
 441                 const struct attribute *attr, const char *group)
 442 {
 443 }
 444
 445 static inline int sysfs_merge_group(struct kobject *kobj,
 446                        const struct attribute_group *grp)
 447 {
 448         return 0;
 449 }
 450
 451 static inline void sysfs_unmerge_group(struct kobject *kobj,
 452                        const struct attribute_group *grp)
 453 {
 454 }
 455
 456 static inline int sysfs_add_link_to_group(struct kobject *kobj,
 457                 const char *group_name, struct kobject *target,
 458                 const char *link_name)
 459 {
 460         return 0;
 461 }
 462
 463 static inline void sysfs_remove_link_from_group(struct kobject *kobj,
 464                 const char *group_name, const char *link_name)
 465 {
 466 }
 467
 468 static inline int __compat_only_sysfs_link_entry_to_kobj(
 469         struct kobject *kobj,
 470         struct kobject *target_kobj,
 471         const char *target_name)
 472 {
 473         return 0;
 474 }
 475
 476 static inline void sysfs_notify(struct kobject *kobj, const char *dir,
 477                                 const char *attr)
 478 {
 479 }
 480
 481 static inline int __must_check sysfs_init(void)
 482 {
 483         return 0;
 484 }
 485
 486 static inline void sysfs_enable_ns(struct kernfs_node *kn)
 487 {
 488 }
 489
 490 #endif /* CONFIG_SYSFS */
 491
 492 static inline int __must_check sysfs_create_file(struct kobject *kobj,
 493                                                  const struct attribute *attr)
 494 {
 495         return sysfs_create_file_ns(kobj, attr, NULL);
 496 }
 497
 498 static inline void sysfs_remove_file(struct kobject *kobj,
 499                                      const struct attribute *attr)
 500 {
 501         sysfs_remove_file_ns(kobj, attr, NULL);
 502 }
 503
 504 static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
 505                                     const char *old_name, const char *new_name)
 506 {
 507         return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);
 508 }
 509
 510 static inline void sysfs_notify_dirent(struct kernfs_node *kn)
 511 {
 512         kernfs_notify(kn);
 513 }
 514
 515 static inline struct kernfs_node *sysfs_get_dirent(struct kernfs_node *parent,
 516                                                    const char *name)
 517 {
 518         return kernfs_find_and_get(parent, name);
 519 }
 520
 521 static inline struct kernfs_node *sysfs_get(struct kernfs_node *kn)
 522 {
 523         kernfs_get(kn);
 524         return kn;
 525 }
 526
 527 static inline void sysfs_put(struct kernfs_node *kn)
 528 {
 529         kernfs_put(kn);
 530 }
 531
 532 #endif /* _SYSFS_H_ */