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/compiler.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/kref.h>
  26 #include <linux/kernel.h>
  27 #include <linux/wait.h>
  28 #include <asm/atomic.h>
  29
  30 #define KOBJ_NAME_LEN                   20
  31 #define UEVENT_HELPER_PATH_LEN          256
  32
  33 /* path to the userspace helper executed on an event */
  34 extern char uevent_helper[];
  35
  36 /* counter to tag the uevent, read only except for the kobject core */
  37 extern u64 uevent_seqnum;
  38
  39 /*
  40  * The actions here must match the index to the string array
  41  * in lib/kobject_uevent.c
  42  *
  43  * Do not add new actions here without checking with the driver-core
  44  * maintainers. Action strings are not meant to express subsystem
  45  * or device specific properties. In most cases you want to send a
  46  * kobject_uevent_env(kobj, KOBJ_CHANGE, env) with additional event
  47  * specific variables added to the event environment.
  48  */
  49 enum kobject_action {
  50         KOBJ_ADD,
  51         KOBJ_REMOVE,
  52         KOBJ_CHANGE,
  53         KOBJ_MOVE,
  54         KOBJ_ONLINE,
  55         KOBJ_OFFLINE,
  56         KOBJ_MAX
  57 };
  58
  59 /* The list of strings defining the valid kobject actions as specified above */
  60 extern const char *kobject_actions[];
  61
  62 struct kobject {
  63         const char              * k_name;
  64         char                    name[KOBJ_NAME_LEN];
  65         struct kref             kref;
  66         struct list_head        entry;
  67         struct kobject          * parent;
  68         struct kset             * kset;
  69         struct kobj_type        * ktype;
  70         struct sysfs_dirent     * sd;
  71         wait_queue_head_t       poll;
  72 };
  73
  74 extern int kobject_set_name(struct kobject *, const char *, ...)
  75         __attribute__((format(printf,2,3)));
  76
  77 static inline const char * kobject_name(const struct kobject * kobj)
  78 {
  79         return kobj->k_name;
  80 }
  81
  82 extern void kobject_init(struct kobject *);
  83 extern void kobject_cleanup(struct kobject *);
  84
  85 extern int __must_check kobject_add(struct kobject *);
  86 extern int __must_check kobject_shadow_add(struct kobject *kobj,
  87                                            struct sysfs_dirent *shadow_parent);
  88 extern void kobject_del(struct kobject *);
  89
  90 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  91 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  92                                               struct sysfs_dirent *new_parent,
  93                                               const char *new_name);
  94 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  95
  96 extern int __must_check kobject_register(struct kobject *);
  97 extern void kobject_unregister(struct kobject *);
  98
  99 extern struct kobject * kobject_get(struct kobject *);
 100 extern void kobject_put(struct kobject *);
 101
 102 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
 103                                             struct kobject *, const char *);
 104 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
 105
 106 extern char * kobject_get_path(struct kobject *, gfp_t);
 107
 108 struct kobj_type {
 109         void (*release)(struct kobject *);
 110         struct sysfs_ops        * sysfs_ops;
 111         struct attribute        ** default_attrs;
 112 };
 113
 114
 115 /**
 116  *      kset - a set of kobjects of a specific type, belonging
 117  *      to a specific subsystem.
 118  *
 119  *      All kobjects of a kset should be embedded in an identical
 120  *      type. This type may have a descriptor, which the kset points
 121  *      to. This allows there to exist sets of objects of the same
 122  *      type in different subsystems.
 123  *
 124  *      A subsystem does not have to be a list of only one type
 125  *      of object; multiple ksets can belong to one subsystem. All
 126  *      ksets of a subsystem share the subsystem's lock.
 127  *
 128  *      Each kset can support specific event variables; it can
 129  *      supress the event generation or add subsystem specific
 130  *      variables carried with the event.
 131  */
 132 struct kset_uevent_ops {
 133         int (*filter)(struct kset *kset, struct kobject *kobj);
 134         const char *(*name)(struct kset *kset, struct kobject *kobj);
 135         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 136                         int num_envp, char *buffer, int buffer_size);
 137 };
 138
 139 struct kset {
 140         struct kobj_type        * ktype;
 141         struct list_head        list;
 142         spinlock_t              list_lock;
 143         struct kobject          kobj;
 144         struct kset_uevent_ops  * uevent_ops;
 145 };
 146
 147
 148 extern void kset_init(struct kset * k);
 149 extern int __must_check kset_add(struct kset * k);
 150 extern int __must_check kset_register(struct kset * k);
 151 extern void kset_unregister(struct kset * k);
 152
 153 static inline struct kset * to_kset(struct kobject * kobj)
 154 {
 155         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 156 }
 157
 158 static inline struct kset * kset_get(struct kset * k)
 159 {
 160         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 161 }
 162
 163 static inline void kset_put(struct kset * k)
 164 {
 165         kobject_put(&k->kobj);
 166 }
 167
 168 static inline struct kobj_type * get_ktype(struct kobject * k)
 169 {
 170         if (k->kset && k->kset->ktype)
 171                 return k->kset->ktype;
 172         else
 173                 return k->ktype;
 174 }
 175
 176 extern struct kobject * kset_find_obj(struct kset *, const char *);
 177
 178
 179 /**
 180  * Use this when initializing an embedded kset with no other
 181  * fields to initialize.
 182  */
 183 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 184
 185
 186 #define decl_subsys(_name,_type,_uevent_ops) \
 187 struct kset _name##_subsys = { \
 188         .kobj = { .name = __stringify(_name) }, \
 189         .ktype = _type, \
 190         .uevent_ops =_uevent_ops, \
 191 }
 192 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 193 struct kset _varname##_subsys = { \
 194         .kobj = { .name = __stringify(_name) }, \
 195         .ktype = _type, \
 196         .uevent_ops =_uevent_ops, \
 197 }
 198
 199 /* The global /sys/kernel/ subsystem for people to chain off of */
 200 extern struct kset kernel_subsys;
 201 /* The global /sys/hypervisor/ subsystem  */
 202 extern struct kset hypervisor_subsys;
 203
 204 /**
 205  * Helpers for setting the kset of registered objects.
 206  * Often, a registered object belongs to a kset embedded in a
 207  * subsystem. These do no magic, just make the resulting code
 208  * easier to follow.
 209  */
 210
 211 /**
 212  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 213  *      @obj:           ptr to some object type.
 214  *      @subsys:        a subsystem object (not a ptr).
 215  *
 216  *      Can be used for any object type with an embedded ->kobj.
 217  */
 218
 219 #define kobj_set_kset_s(obj,subsys) \
 220         (obj)->kobj.kset = &(subsys)
 221
 222 /**
 223  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 224  *      @obj:           ptr to some object type.
 225  *      @subsys:        a subsystem object (not a ptr).
 226  *
 227  *      Can be used for any object type with an embedded ->kset.
 228  *      Sets the kset of @obj's  embedded kobject (via its embedded
 229  *      kset) to @subsys.kset. This makes @obj a member of that
 230  *      kset.
 231  */
 232
 233 #define kset_set_kset_s(obj,subsys) \
 234         (obj)->kset.kobj.kset = &(subsys)
 235
 236 /**
 237  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 238  *      @obj:           ptr to some object type.
 239  *      @subsys:        a subsystem object (not a ptr).
 240  *
 241  *      Can be used for any object type with an embedded ->subsys.
 242  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 243  *      the object a member of that kset.
 244  */
 245
 246 #define subsys_set_kset(obj,_subsys) \
 247         (obj)->subsys.kobj.kset = &(_subsys)
 248
 249 extern void subsystem_init(struct kset *);
 250 extern int __must_check subsystem_register(struct kset *);
 251 extern void subsystem_unregister(struct kset *);
 252
 253 static inline struct kset *subsys_get(struct kset *s)
 254 {
 255         if (s)
 256                 return kset_get(s);
 257         return NULL;
 258 }
 259
 260 static inline void subsys_put(struct kset *s)
 261 {
 262         kset_put(s);
 263 }
 264
 265 struct subsys_attribute {
 266         struct attribute attr;
 267         ssize_t (*show)(struct kset *, char *);
 268         ssize_t (*store)(struct kset *, const char *, size_t);
 269 };
 270
 271 extern int __must_check subsys_create_file(struct kset *,
 272                                         struct subsys_attribute *);
 273
 274 #if defined(CONFIG_HOTPLUG)
 275 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 276 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 277                         char *envp[]);
 278
 279 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 280                         char *buffer, int buffer_size, int *cur_len,
 281                         const char *format, ...)
 282         __attribute__((format (printf, 7, 8)));
 283 #else
 284 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 285 { return 0; }
 286 static inline int kobject_uevent_env(struct kobject *kobj,
 287                                       enum kobject_action action,
 288                                       char *envp[])
 289 { return 0; }
 290
 291 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 292                                       char *buffer, int buffer_size, int *cur_len,
 293                                       const char *format, ...)
 294 { return 0; }
 295 #endif
 296
 297 #endif /* __KERNEL__ */
 298 #endif /* _KOBJECT_H_ */