include/linux/kobject.h

   1 /*
   2  * kobject.h - generic kernel object infrastructure.
   3  *
   4  * Copyright (c) 2002-2003      Patrick Mochel
   5  * Copyright (c) 2002-2003      Open Source Development Labs
   6  *
   7  * This file is released under the GPLv2.
   8  *
   9  *
  10  * Please read Documentation/kobject.txt before using the kobject
  11  * interface, ESPECIALLY the parts about reference counts and object
  12  * destructors.
  13  */
  14
  15 #ifndef _KOBJECT_H_
  16 #define _KOBJECT_H_
  17
  18 #ifdef __KERNEL__
  19
  20 #include <linux/types.h>
  21 #include <linux/list.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/rwsem.h>
  24 #include <linux/kref.h>
  25 #include <asm/atomic.h>
  26
  27 #define KOBJ_NAME_LEN   20
  28
  29 struct kobject {
  30         char                    * k_name;
  31         char                    name[KOBJ_NAME_LEN];
  32         struct kref             kref;
  33         struct list_head        entry;
  34         struct kobject          * parent;
  35         struct kset             * kset;
  36         struct kobj_type        * ktype;
  37         struct dentry           * dentry;
  38 };
  39
  40 extern int kobject_set_name(struct kobject *, const char *, ...)
  41         __attribute__((format(printf,2,3)));
  42
  43 static inline char * kobject_name(struct kobject * kobj)
  44 {
  45         return kobj->k_name;
  46 }
  47
  48 extern void kobject_init(struct kobject *);
  49 extern void kobject_cleanup(struct kobject *);
  50
  51 extern int kobject_add(struct kobject *);
  52 extern void kobject_del(struct kobject *);
  53
  54 extern int kobject_rename(struct kobject *, char *new_name);
  55
  56 extern int kobject_register(struct kobject *);
  57 extern void kobject_unregister(struct kobject *);
  58
  59 extern struct kobject * kobject_get(struct kobject *);
  60 extern void kobject_put(struct kobject *);
  61
  62 extern void kobject_hotplug(const char *action, struct kobject *);
  63
  64 extern char * kobject_get_path(struct kset *, struct kobject *, int);
  65
  66 struct kobj_type {
  67         void (*release)(struct kobject *);
  68         struct sysfs_ops        * sysfs_ops;
  69         struct attribute        ** default_attrs;
  70 };
  71
  72
  73 /**
  74  *      kset - a set of kobjects of a specific type, belonging
  75  *      to a specific subsystem.
  76  *
  77  *      All kobjects of a kset should be embedded in an identical
  78  *      type. This type may have a descriptor, which the kset points
  79  *      to. This allows there to exist sets of objects of the same
  80  *      type in different subsystems.
  81  *
  82  *      A subsystem does not have to be a list of only one type
  83  *      of object; multiple ksets can belong to one subsystem. All
  84  *      ksets of a subsystem share the subsystem's lock.
  85  *
  86  *      Each kset can support hotplugging; if it does, it will be given
  87  *      the opportunity to filter out specific kobjects from being
  88  *      reported, as well as to add its own "data" elements to the
  89  *      environment being passed to the hotplug helper.
  90  */
  91 struct kset_hotplug_ops {
  92         int (*filter)(struct kset *kset, struct kobject *kobj);
  93         char *(*name)(struct kset *kset, struct kobject *kobj);
  94         int (*hotplug)(struct kset *kset, struct kobject *kobj, char **envp,
  95                         int num_envp, char *buffer, int buffer_size);
  96 };
  97
  98 struct kset {
  99         struct subsystem        * subsys;
 100         struct kobj_type        * ktype;
 101         struct list_head        list;
 102         struct kobject          kobj;
 103         struct kset_hotplug_ops * hotplug_ops;
 104 };
 105
 106
 107 extern void kset_init(struct kset * k);
 108 extern int kset_add(struct kset * k);
 109 extern int kset_register(struct kset * k);
 110 extern void kset_unregister(struct kset * k);
 111
 112 static inline struct kset * to_kset(struct kobject * kobj)
 113 {
 114         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 115 }
 116
 117 static inline struct kset * kset_get(struct kset * k)
 118 {
 119         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 120 }
 121
 122 static inline void kset_put(struct kset * k)
 123 {
 124         kobject_put(&k->kobj);
 125 }
 126
 127 static inline struct kobj_type * get_ktype(struct kobject * k)
 128 {
 129         if (k->kset && k->kset->ktype)
 130                 return k->kset->ktype;
 131         else
 132                 return k->ktype;
 133 }
 134
 135 extern struct kobject * kset_find_obj(struct kset *, const char *);
 136
 137
 138 /**
 139  * Use this when initializing an embedded kset with no other
 140  * fields to initialize.
 141  */
 142 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 143
 144
 145
 146 struct subsystem {
 147         struct kset             kset;
 148         struct rw_semaphore     rwsem;
 149 };
 150
 151 #define decl_subsys(_name,_type,_hotplug_ops) \
 152 struct subsystem _name##_subsys = { \
 153         .kset = { \
 154                 .kobj = { .name = __stringify(_name) }, \
 155                 .ktype = _type, \
 156                 .hotplug_ops =_hotplug_ops, \
 157         } \
 158 }
 159 #define decl_subsys_name(_varname,_name,_type,_hotplug_ops) \
 160 struct subsystem _varname##_subsys = { \
 161         .kset = { \
 162                 .kobj = { .name = __stringify(_name) }, \
 163                 .ktype = _type, \
 164                 .hotplug_ops =_hotplug_ops, \
 165         } \
 166 }
 167
 168
 169 /**
 170  * Helpers for setting the kset of registered objects.
 171  * Often, a registered object belongs to a kset embedded in a
 172  * subsystem. These do no magic, just make the resulting code
 173  * easier to follow.
 174  */
 175
 176 /**
 177  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 178  *      @obj:           ptr to some object type.
 179  *      @subsys:        a subsystem object (not a ptr).
 180  *
 181  *      Can be used for any object type with an embedded ->kobj.
 182  */
 183
 184 #define kobj_set_kset_s(obj,subsys) \
 185         (obj)->kobj.kset = &(subsys).kset
 186
 187 /**
 188  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 189  *      @obj:           ptr to some object type.
 190  *      @subsys:        a subsystem object (not a ptr).
 191  *
 192  *      Can be used for any object type with an embedded ->kset.
 193  *      Sets the kset of @obj's  embedded kobject (via its embedded
 194  *      kset) to @subsys.kset. This makes @obj a member of that
 195  *      kset.
 196  */
 197
 198 #define kset_set_kset_s(obj,subsys) \
 199         (obj)->kset.kobj.kset = &(subsys).kset
 200
 201 /**
 202  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 203  *      @obj:           ptr to some object type.
 204  *      @subsys:        a subsystem object (not a ptr).
 205  *
 206  *      Can be used for any object type with an embedded ->subsys.
 207  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 208  *      the object a member of that kset.
 209  */
 210
 211 #define subsys_set_kset(obj,_subsys) \
 212         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 213
 214 extern void subsystem_init(struct subsystem *);
 215 extern int subsystem_register(struct subsystem *);
 216 extern void subsystem_unregister(struct subsystem *);
 217
 218 static inline struct subsystem * subsys_get(struct subsystem * s)
 219 {
 220         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 221 }
 222
 223 static inline void subsys_put(struct subsystem * s)
 224 {
 225         kset_put(&s->kset);
 226 }
 227
 228 struct subsys_attribute {
 229         struct attribute attr;
 230         ssize_t (*show)(struct subsystem *, char *);
 231         ssize_t (*store)(struct subsystem *, const char *, size_t);
 232 };
 233
 234 extern int subsys_create_file(struct subsystem * , struct subsys_attribute *);
 235 extern void subsys_remove_file(struct subsystem * , struct subsys_attribute *);
 236
 237 #endif /* __KERNEL__ */
 238 #endif /* _KOBJECT_H_ */