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[mirror_ubuntu-bionic-kernel.git] / include / linux / sysfs.h

/* SPDX-License-Identifier: GPL-2.0 */
/*
 * sysfs.h - definitions for the device driver filesystem
 *
 * Copyright (c) 2001,2002 Patrick Mochel
 * Copyright (c) 2004 Silicon Graphics, Inc.
 * Copyright (c) 2007 SUSE Linux Products GmbH
 * Copyright (c) 2007 Tejun Heo <teheo@suse.de>
 *
 * Please see Documentation/filesystems/sysfs.txt for more information.
 */

#ifndef _SYSFS_H_
#define _SYSFS_H_

#include <linux/kernfs.h>
#include <linux/compiler.h>
#include <linux/errno.h>
#include <linux/list.h>
#include <linux/lockdep.h>
#include <linux/kobject_ns.h>
#include <linux/stat.h>
#include <linux/atomic.h>

struct kobject;
struct module;
struct bin_attribute;
enum kobj_ns_type;

struct attribute {
        const char              *name;
        umode_t                 mode;
#ifdef CONFIG_DEBUG_LOCK_ALLOC
        bool                    ignore_lockdep:1;
        struct lock_class_key   *key;
        struct lock_class_key   skey;
#endif
};

/**
 *      sysfs_attr_init - initialize a dynamically allocated sysfs attribute
 *      @attr: struct attribute to initialize
 *
 *      Initialize a dynamically allocated struct attribute so we can
 *      make lockdep happy.  This is a new requirement for attributes
 *      and initially this is only needed when lockdep is enabled.
 *      Lockdep gives a nice error when your attribute is added to
 *      sysfs if you don't have this.
 */
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#define sysfs_attr_init(attr)                           \
do {                                                    \
        static struct lock_class_key __key;             \
                                                        \
        (attr)->key = &__key;                           \
} while (0)
#else
#define sysfs_attr_init(attr) do {} while (0)
#endif

/**
 * struct attribute_group - data structure used to declare an attribute group.
 * @name:       Optional: Attribute group name
 *              If specified, the attribute group will be created in
 *              a new subdirectory with this name.
 * @is_visible: Optional: Function to return permissions associated with an
 *              attribute of the group. Will be called repeatedly for each
 *              non-binary attribute in the group. Only read/write
 *              permissions as well as SYSFS_PREALLOC are accepted. Must
 *              return 0 if an attribute is not visible. The returned value
 *              will replace static permissions defined in struct attribute.
 * @is_bin_visible:
 *              Optional: Function to return permissions associated with a
 *              binary attribute of the group. Will be called repeatedly
 *              for each binary attribute in the group. Only read/write
 *              permissions as well as SYSFS_PREALLOC are accepted. Must
 *              return 0 if a binary attribute is not visible. The returned
 *              value will replace static permissions defined in
 *              struct bin_attribute.
 * @attrs:      Pointer to NULL terminated list of attributes.
 * @bin_attrs:  Pointer to NULL terminated list of binary attributes.
 *              Either attrs or bin_attrs or both must be provided.
 */
struct attribute_group {
        const char              *name;
        umode_t                 (*is_visible)(struct kobject *,
                                              struct attribute *, int);
        umode_t                 (*is_bin_visible)(struct kobject *,
                                                  struct bin_attribute *, int);
        struct attribute        **attrs;
        struct bin_attribute    **bin_attrs;
};

/**
 * Use these macros to make defining attributes easier. See include/linux/device.h
 * for examples..
 */

#define SYSFS_PREALLOC 010000

#define __ATTR(_name, _mode, _show, _store) {                           \
        .attr = {.name = __stringify(_name),                            \
                 .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },             \
        .show   = _show,                                                \
        .store  = _store,                                               \
}

#define __ATTR_PREALLOC(_name, _mode, _show, _store) {                  \
        .attr = {.name = __stringify(_name),                            \
                 .mode = SYSFS_PREALLOC | VERIFY_OCTAL_PERMISSIONS(_mode) },\
        .show   = _show,                                                \
        .store  = _store,                                               \
}

#define __ATTR_RO(_name) {                                              \
        .attr   = { .name = __stringify(_name), .mode = S_IRUGO },      \
        .show   = _name##_show,                                         \
}

#define __ATTR_RO_MODE(_name, _mode) {                                  \
        .attr   = { .name = __stringify(_name),                         \
                    .mode = VERIFY_OCTAL_PERMISSIONS(_mode) },          \
        .show   = _name##_show,                                         \
}

#define __ATTR_WO(_name) {                                              \
        .attr   = { .name = __stringify(_name), .mode = S_IWUSR },      \
        .store  = _name##_store,                                        \
}

#define __ATTR_RW(_name) __ATTR(_name, (S_IWUSR | S_IRUGO),             \
                         _name##_show, _name##_store)

#define __ATTR_NULL { .attr = { .name = NULL } }

#ifdef CONFIG_DEBUG_LOCK_ALLOC
#define __ATTR_IGNORE_LOCKDEP(_name, _mode, _show, _store) {    \
        .attr = {.name = __stringify(_name), .mode = _mode,     \
                        .ignore_lockdep = true },               \
        .show           = _show,                                \
        .store          = _store,                               \
}
#else
#define __ATTR_IGNORE_LOCKDEP   __ATTR
#endif

#define __ATTRIBUTE_GROUPS(_name)                               \
static const struct attribute_group *_name##_groups[] = {       \
        &_name##_group,                                         \
        NULL,                                                   \
}

#define ATTRIBUTE_GROUPS(_name)                                 \
static const struct attribute_group _name##_group = {           \
        .attrs = _name##_attrs,                                 \
};                                                              \
__ATTRIBUTE_GROUPS(_name)

struct file;
struct vm_area_struct;

struct bin_attribute {
        struct attribute        attr;
        size_t                  size;
        void                    *private;
        ssize_t (*read)(struct file *, struct kobject *, struct bin_attribute *,
                        char *, loff_t, size_t);
        ssize_t (*write)(struct file *, struct kobject *, struct bin_attribute *,
                         char *, loff_t, size_t);
        int (*mmap)(struct file *, struct kobject *, struct bin_attribute *attr,
                    struct vm_area_struct *vma);
};

/**
 *      sysfs_bin_attr_init - initialize a dynamically allocated bin_attribute
 *      @attr: struct bin_attribute to initialize
 *
 *      Initialize a dynamically allocated struct bin_attribute so we
 *      can make lockdep happy.  This is a new requirement for
 *      attributes and initially this is only needed when lockdep is
 *      enabled.  Lockdep gives a nice error when your attribute is
 *      added to sysfs if you don't have this.
 */
#define sysfs_bin_attr_init(bin_attr) sysfs_attr_init(&(bin_attr)->attr)

/* macros to create static binary attributes easier */
#define __BIN_ATTR(_name, _mode, _read, _write, _size) {                \
        .attr = { .name = __stringify(_name), .mode = _mode },          \
        .read   = _read,                                                \
        .write  = _write,                                               \
        .size   = _size,                                                \
}

#define __BIN_ATTR_RO(_name, _size) {                                   \
        .attr   = { .name = __stringify(_name), .mode = S_IRUGO },      \
        .read   = _name##_read,                                         \
        .size   = _size,                                                \
}

#define __BIN_ATTR_RW(_name, _size) __BIN_ATTR(_name,                   \
                                   (S_IWUSR | S_IRUGO), _name##_read,   \
                                   _name##_write, _size)

#define __BIN_ATTR_NULL __ATTR_NULL

#define BIN_ATTR(_name, _mode, _read, _write, _size)                    \
struct bin_attribute bin_attr_##_name = __BIN_ATTR(_name, _mode, _read, \
                                        _write, _size)

#define BIN_ATTR_RO(_name, _size)                                       \
struct bin_attribute bin_attr_##_name = __BIN_ATTR_RO(_name, _size)

#define BIN_ATTR_RW(_name, _size)                                       \
struct bin_attribute bin_attr_##_name = __BIN_ATTR_RW(_name, _size)

struct sysfs_ops {
        ssize_t (*show)(struct kobject *, struct attribute *, char *);
        ssize_t (*store)(struct kobject *, struct attribute *, const char *, size_t);
};

#ifdef CONFIG_SYSFS

int __must_check sysfs_create_dir_ns(struct kobject *kobj, const void *ns);
void sysfs_remove_dir(struct kobject *kobj);
int __must_check sysfs_rename_dir_ns(struct kobject *kobj, const char *new_name,
                                     const void *new_ns);
int __must_check sysfs_move_dir_ns(struct kobject *kobj,
                                   struct kobject *new_parent_kobj,
                                   const void *new_ns);
int __must_check sysfs_create_mount_point(struct kobject *parent_kobj,
                                          const char *name);
void sysfs_remove_mount_point(struct kobject *parent_kobj,
                              const char *name);

int __must_check sysfs_create_file_ns(struct kobject *kobj,
                                      const struct attribute *attr,
                                      const void *ns);
int __must_check sysfs_create_files(struct kobject *kobj,
                                   const struct attribute **attr);
int __must_check sysfs_chmod_file(struct kobject *kobj,
                                  const struct attribute *attr, umode_t mode);
void sysfs_remove_file_ns(struct kobject *kobj, const struct attribute *attr,
                          const void *ns);
bool sysfs_remove_file_self(struct kobject *kobj, const struct attribute *attr);
void sysfs_remove_files(struct kobject *kobj, const struct attribute **attr);

int __must_check sysfs_create_bin_file(struct kobject *kobj,
                                       const struct bin_attribute *attr);
void sysfs_remove_bin_file(struct kobject *kobj,
                           const struct bin_attribute *attr);

int __must_check sysfs_create_link(struct kobject *kobj, struct kobject *target,
                                   const char *name);
int __must_check sysfs_create_link_nowarn(struct kobject *kobj,
                                          struct kobject *target,
                                          const char *name);
void sysfs_remove_link(struct kobject *kobj, const char *name);

int sysfs_rename_link_ns(struct kobject *kobj, struct kobject *target,
                         const char *old_name, const char *new_name,
                         const void *new_ns);

void sysfs_delete_link(struct kobject *dir, struct kobject *targ,
                        const char *name);

int __must_check sysfs_create_group(struct kobject *kobj,
                                    const struct attribute_group *grp);
int __must_check sysfs_create_groups(struct kobject *kobj,
                                     const struct attribute_group **groups);
int sysfs_update_group(struct kobject *kobj,
                       const struct attribute_group *grp);
void sysfs_remove_group(struct kobject *kobj,
                        const struct attribute_group *grp);
void sysfs_remove_groups(struct kobject *kobj,
                         const struct attribute_group **groups);
int sysfs_add_file_to_group(struct kobject *kobj,
                        const struct attribute *attr, const char *group);
void sysfs_remove_file_from_group(struct kobject *kobj,
                        const struct attribute *attr, const char *group);
int sysfs_merge_group(struct kobject *kobj,
                       const struct attribute_group *grp);
void sysfs_unmerge_group(struct kobject *kobj,
                       const struct attribute_group *grp);
int sysfs_add_link_to_group(struct kobject *kobj, const char *group_name,
                            struct kobject *target, const char *link_name);
void sysfs_remove_link_from_group(struct kobject *kobj, const char *group_name,
                                  const char *link_name);
int __compat_only_sysfs_link_entry_to_kobj(struct kobject *kobj,
                                      struct kobject *target_kobj,
                                      const char *target_name);

void sysfs_notify(struct kobject *kobj, const char *dir, const char *attr);

int __must_check sysfs_init(void);

static inline void sysfs_enable_ns(struct kernfs_node *kn)
{
        return kernfs_enable_ns(kn);
}

#else /* CONFIG_SYSFS */

static inline int sysfs_create_dir_ns(struct kobject *kobj, const void *ns)
{
        return 0;
}

static inline void sysfs_remove_dir(struct kobject *kobj)
{
}

static inline int sysfs_rename_dir_ns(struct kobject *kobj,
                                      const char *new_name, const void *new_ns)
{
        return 0;
}

static inline int sysfs_move_dir_ns(struct kobject *kobj,
                                    struct kobject *new_parent_kobj,
                                    const void *new_ns)
{
        return 0;
}

static inline int sysfs_create_mount_point(struct kobject *parent_kobj,
                                           const char *name)
{
        return 0;
}

static inline void sysfs_remove_mount_point(struct kobject *parent_kobj,
                                            const char *name)
{
}

static inline int sysfs_create_file_ns(struct kobject *kobj,
                                       const struct attribute *attr,
                                       const void *ns)
{
        return 0;
}

static inline int sysfs_create_files(struct kobject *kobj,
                                    const struct attribute **attr)
{
        return 0;
}

static inline int sysfs_chmod_file(struct kobject *kobj,
                                   const struct attribute *attr, umode_t mode)
{
        return 0;
}

static inline void sysfs_remove_file_ns(struct kobject *kobj,
                                        const struct attribute *attr,
                                        const void *ns)
{
}

static inline bool sysfs_remove_file_self(struct kobject *kobj,
                                          const struct attribute *attr)
{
        return false;
}

static inline void sysfs_remove_files(struct kobject *kobj,
                                     const struct attribute **attr)
{
}

static inline int sysfs_create_bin_file(struct kobject *kobj,
                                        const struct bin_attribute *attr)
{
        return 0;
}

static inline void sysfs_remove_bin_file(struct kobject *kobj,
                                         const struct bin_attribute *attr)
{
}

static inline int sysfs_create_link(struct kobject *kobj,
                                    struct kobject *target, const char *name)
{
        return 0;
}

static inline int sysfs_create_link_nowarn(struct kobject *kobj,
                                           struct kobject *target,
                                           const char *name)
{
        return 0;
}

static inline void sysfs_remove_link(struct kobject *kobj, const char *name)
{
}

static inline int sysfs_rename_link_ns(struct kobject *k, struct kobject *t,
                                       const char *old_name,
                                       const char *new_name, const void *ns)
{
        return 0;
}

static inline void sysfs_delete_link(struct kobject *k, struct kobject *t,
                                     const char *name)
{
}

static inline int sysfs_create_group(struct kobject *kobj,
                                     const struct attribute_group *grp)
{
        return 0;
}

static inline int sysfs_create_groups(struct kobject *kobj,
                                      const struct attribute_group **groups)
{
        return 0;
}

static inline int sysfs_update_group(struct kobject *kobj,
                                const struct attribute_group *grp)
{
        return 0;
}

static inline void sysfs_remove_group(struct kobject *kobj,
                                      const struct attribute_group *grp)
{
}

static inline void sysfs_remove_groups(struct kobject *kobj,
                                       const struct attribute_group **groups)
{
}

static inline int sysfs_add_file_to_group(struct kobject *kobj,
                const struct attribute *attr, const char *group)
{
        return 0;
}

static inline void sysfs_remove_file_from_group(struct kobject *kobj,
                const struct attribute *attr, const char *group)
{
}

static inline int sysfs_merge_group(struct kobject *kobj,
                       const struct attribute_group *grp)
{
        return 0;
}

static inline void sysfs_unmerge_group(struct kobject *kobj,
                       const struct attribute_group *grp)
{
}

static inline int sysfs_add_link_to_group(struct kobject *kobj,
                const char *group_name, struct kobject *target,
                const char *link_name)
{
        return 0;
}

static inline void sysfs_remove_link_from_group(struct kobject *kobj,
                const char *group_name, const char *link_name)
{
}

static inline int __compat_only_sysfs_link_entry_to_kobj(
        struct kobject *kobj,
        struct kobject *target_kobj,
        const char *target_name)
{
        return 0;
}

static inline void sysfs_notify(struct kobject *kobj, const char *dir,
                                const char *attr)
{
}

static inline int __must_check sysfs_init(void)
{
        return 0;
}

static inline void sysfs_enable_ns(struct kernfs_node *kn)
{
}

#endif /* CONFIG_SYSFS */

static inline int __must_check sysfs_create_file(struct kobject *kobj,
                                                 const struct attribute *attr)
{
        return sysfs_create_file_ns(kobj, attr, NULL);
}

static inline void sysfs_remove_file(struct kobject *kobj,
                                     const struct attribute *attr)
{
        sysfs_remove_file_ns(kobj, attr, NULL);
}

static inline int sysfs_rename_link(struct kobject *kobj, struct kobject *target,
                                    const char *old_name, const char *new_name)
{
        return sysfs_rename_link_ns(kobj, target, old_name, new_name, NULL);
}

static inline void sysfs_notify_dirent(struct kernfs_node *kn)
{
        kernfs_notify(kn);
}

static inline struct kernfs_node *sysfs_get_dirent(struct kernfs_node *parent,
                                                   const char *name)
{
        return kernfs_find_and_get(parent, name);
}

static inline struct kernfs_node *sysfs_get(struct kernfs_node *kn)
{
        kernfs_get(kn);
        return kn;
}

static inline void sysfs_put(struct kernfs_node *kn)
{
        kernfs_put(kn);
}

#endif /* _SYSFS_H_ */