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 struct kset_uevent_ops {
 115         int (*filter)(struct kset *kset, struct kobject *kobj);
 116         const char *(*name)(struct kset *kset, struct kobject *kobj);
 117         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 118                         int num_envp, char *buffer, int buffer_size);
 119 };
 120
 121 /*
 122  *      struct kset - a set of kobjects of a specific type, belonging
 123  *      to a specific subsystem.
 124  *
 125  *      All kobjects of a kset should be embedded in an identical
 126  *      type. This type may have a descriptor, which the kset points
 127  *      to. This allows there to exist sets of objects of the same
 128  *      type in different subsystems.
 129  *
 130  *      A subsystem does not have to be a list of only one type
 131  *      of object; multiple ksets can belong to one subsystem. All
 132  *      ksets of a subsystem share the subsystem's lock.
 133  *
 134  *      Each kset can support specific event variables; it can
 135  *      supress the event generation or add subsystem specific
 136  *      variables carried with the event.
 137  */
 138 struct kset {
 139         struct kobj_type        * ktype;
 140         struct list_head        list;
 141         spinlock_t              list_lock;
 142         struct kobject          kobj;
 143         struct kset_uevent_ops  * uevent_ops;
 144 };
 145
 146
 147 extern void kset_init(struct kset * k);
 148 extern int __must_check kset_add(struct kset * k);
 149 extern int __must_check kset_register(struct kset * k);
 150 extern void kset_unregister(struct kset * k);
 151
 152 static inline struct kset * to_kset(struct kobject * kobj)
 153 {
 154         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 155 }
 156
 157 static inline struct kset * kset_get(struct kset * k)
 158 {
 159         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 160 }
 161
 162 static inline void kset_put(struct kset * k)
 163 {
 164         kobject_put(&k->kobj);
 165 }
 166
 167 static inline struct kobj_type * get_ktype(struct kobject * k)
 168 {
 169         if (k->kset && k->kset->ktype)
 170                 return k->kset->ktype;
 171         else
 172                 return k->ktype;
 173 }
 174
 175 extern struct kobject * kset_find_obj(struct kset *, const char *);
 176
 177
 178 /*
 179  * Use this when initializing an embedded kset with no other
 180  * fields to initialize.
 181  */
 182 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 183
 184
 185 #define decl_subsys(_name,_type,_uevent_ops) \
 186 struct kset _name##_subsys = { \
 187         .kobj = { .name = __stringify(_name) }, \
 188         .ktype = _type, \
 189         .uevent_ops =_uevent_ops, \
 190 }
 191 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 192 struct kset _varname##_subsys = { \
 193         .kobj = { .name = __stringify(_name) }, \
 194         .ktype = _type, \
 195         .uevent_ops =_uevent_ops, \
 196 }
 197
 198 /* The global /sys/kernel/ subsystem for people to chain off of */
 199 extern struct kset kernel_subsys;
 200 /* The global /sys/hypervisor/ subsystem  */
 201 extern struct kset hypervisor_subsys;
 202
 203 /*
 204  * Helpers for setting the kset of registered objects.
 205  * Often, a registered object belongs to a kset embedded in a
 206  * subsystem. These do no magic, just make the resulting code
 207  * easier to follow.
 208  */
 209
 210 /**
 211  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 212  *      @obj:           ptr to some object type.
 213  *      @subsys:        a subsystem object (not a ptr).
 214  *
 215  *      Can be used for any object type with an embedded ->kobj.
 216  */
 217
 218 #define kobj_set_kset_s(obj,subsys) \
 219         (obj)->kobj.kset = &(subsys)
 220
 221 /**
 222  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 223  *      @obj:           ptr to some object type.
 224  *      @subsys:        a subsystem object (not a ptr).
 225  *
 226  *      Can be used for any object type with an embedded ->kset.
 227  *      Sets the kset of @obj's  embedded kobject (via its embedded
 228  *      kset) to @subsys.kset. This makes @obj a member of that
 229  *      kset.
 230  */
 231
 232 #define kset_set_kset_s(obj,subsys) \
 233         (obj)->kset.kobj.kset = &(subsys)
 234
 235 /**
 236  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 237  *      @obj:           ptr to some object type.
 238  *      @_subsys:       a subsystem object (not a ptr).
 239  *
 240  *      Can be used for any object type with an embedded ->subsys.
 241  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 242  *      the object a member of that kset.
 243  */
 244
 245 #define subsys_set_kset(obj,_subsys) \
 246         (obj)->subsys.kobj.kset = &(_subsys)
 247
 248 extern void subsystem_init(struct kset *);
 249 extern int __must_check subsystem_register(struct kset *);
 250 extern void subsystem_unregister(struct kset *);
 251
 252 static inline struct kset *subsys_get(struct kset *s)
 253 {
 254         if (s)
 255                 return kset_get(s);
 256         return NULL;
 257 }
 258
 259 static inline void subsys_put(struct kset *s)
 260 {
 261         kset_put(s);
 262 }
 263
 264 struct subsys_attribute {
 265         struct attribute attr;
 266         ssize_t (*show)(struct kset *, char *);
 267         ssize_t (*store)(struct kset *, const char *, size_t);
 268 };
 269
 270 extern int __must_check subsys_create_file(struct kset *,
 271                                         struct subsys_attribute *);
 272
 273 #if defined(CONFIG_HOTPLUG)
 274 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 275 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 276                         char *envp[]);
 277
 278 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 279                         char *buffer, int buffer_size, int *cur_len,
 280                         const char *format, ...)
 281         __attribute__((format (printf, 7, 8)));
 282 #else
 283 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 284 { return 0; }
 285 static inline int kobject_uevent_env(struct kobject *kobj,
 286                                       enum kobject_action action,
 287                                       char *envp[])
 288 { return 0; }
 289
 290 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 291                                       char *buffer, int buffer_size, int *cur_len,
 292                                       const char *format, ...)
 293 { return 0; }
 294 #endif
 295
 296 #endif /* __KERNEL__ */
 297 #endif /* _KOBJECT_H_ */