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 /* the actions here must match the proper string in lib/kobject_uevent.c */
  40 typedef int __bitwise kobject_action_t;
  41 enum kobject_action {
  42         KOBJ_ADD        = (__force kobject_action_t) 0x01,      /* exclusive to core */
  43         KOBJ_REMOVE     = (__force kobject_action_t) 0x02,      /* exclusive to core */
  44         KOBJ_CHANGE     = (__force kobject_action_t) 0x03,      /* device state change */
  45         KOBJ_OFFLINE    = (__force kobject_action_t) 0x04,      /* device offline */
  46         KOBJ_ONLINE     = (__force kobject_action_t) 0x05,      /* device online */
  47         KOBJ_MOVE       = (__force kobject_action_t) 0x06,      /* device move */
  48 };
  49
  50 struct kobject {
  51         const char              * k_name;
  52         char                    name[KOBJ_NAME_LEN];
  53         struct kref             kref;
  54         struct list_head        entry;
  55         struct kobject          * parent;
  56         struct kset             * kset;
  57         struct kobj_type        * ktype;
  58         struct dentry           * dentry;
  59         wait_queue_head_t       poll;
  60 };
  61
  62 extern int kobject_set_name(struct kobject *, const char *, ...)
  63         __attribute__((format(printf,2,3)));
  64
  65 static inline const char * kobject_name(const struct kobject * kobj)
  66 {
  67         return kobj->k_name;
  68 }
  69
  70 extern void kobject_init(struct kobject *);
  71 extern void kobject_cleanup(struct kobject *);
  72
  73 extern int __must_check kobject_add(struct kobject *);
  74 extern int __must_check kobject_shadow_add(struct kobject *, struct dentry *);
  75 extern void kobject_del(struct kobject *);
  76
  77 extern int __must_check kobject_rename(struct kobject *, const char *new_name);
  78 extern int __must_check kobject_shadow_rename(struct kobject *kobj,
  79                                                 struct dentry *new_parent,
  80                                                 const char *new_name);
  81 extern int __must_check kobject_move(struct kobject *, struct kobject *);
  82
  83 extern int __must_check kobject_register(struct kobject *);
  84 extern void kobject_unregister(struct kobject *);
  85
  86 extern struct kobject * kobject_get(struct kobject *);
  87 extern void kobject_put(struct kobject *);
  88
  89 extern struct kobject *kobject_kset_add_dir(struct kset *kset,
  90                                             struct kobject *, const char *);
  91 extern struct kobject *kobject_add_dir(struct kobject *, const char *);
  92
  93 extern char * kobject_get_path(struct kobject *, gfp_t);
  94
  95 struct kobj_type {
  96         void (*release)(struct kobject *);
  97         struct sysfs_ops        * sysfs_ops;
  98         struct attribute        ** default_attrs;
  99 };
 100
 101
 102 /**
 103  *      kset - a set of kobjects of a specific type, belonging
 104  *      to a specific subsystem.
 105  *
 106  *      All kobjects of a kset should be embedded in an identical
 107  *      type. This type may have a descriptor, which the kset points
 108  *      to. This allows there to exist sets of objects of the same
 109  *      type in different subsystems.
 110  *
 111  *      A subsystem does not have to be a list of only one type
 112  *      of object; multiple ksets can belong to one subsystem. All
 113  *      ksets of a subsystem share the subsystem's lock.
 114  *
 115  *      Each kset can support specific event variables; it can
 116  *      supress the event generation or add subsystem specific
 117  *      variables carried with the event.
 118  */
 119 struct kset_uevent_ops {
 120         int (*filter)(struct kset *kset, struct kobject *kobj);
 121         const char *(*name)(struct kset *kset, struct kobject *kobj);
 122         int (*uevent)(struct kset *kset, struct kobject *kobj, char **envp,
 123                         int num_envp, char *buffer, int buffer_size);
 124 };
 125
 126 struct kset {
 127         struct subsystem        * subsys;
 128         struct kobj_type        * ktype;
 129         struct list_head        list;
 130         spinlock_t              list_lock;
 131         struct kobject          kobj;
 132         struct kset_uevent_ops  * uevent_ops;
 133 };
 134
 135
 136 extern void kset_init(struct kset * k);
 137 extern int __must_check kset_add(struct kset * k);
 138 extern int __must_check kset_register(struct kset * k);
 139 extern void kset_unregister(struct kset * k);
 140
 141 static inline struct kset * to_kset(struct kobject * kobj)
 142 {
 143         return kobj ? container_of(kobj,struct kset,kobj) : NULL;
 144 }
 145
 146 static inline struct kset * kset_get(struct kset * k)
 147 {
 148         return k ? to_kset(kobject_get(&k->kobj)) : NULL;
 149 }
 150
 151 static inline void kset_put(struct kset * k)
 152 {
 153         kobject_put(&k->kobj);
 154 }
 155
 156 static inline struct kobj_type * get_ktype(struct kobject * k)
 157 {
 158         if (k->kset && k->kset->ktype)
 159                 return k->kset->ktype;
 160         else
 161                 return k->ktype;
 162 }
 163
 164 extern struct kobject * kset_find_obj(struct kset *, const char *);
 165
 166
 167 /**
 168  * Use this when initializing an embedded kset with no other
 169  * fields to initialize.
 170  */
 171 #define set_kset_name(str)      .kset = { .kobj = { .name = str } }
 172
 173
 174
 175 struct subsystem {
 176         struct kset             kset;
 177 };
 178
 179 #define decl_subsys(_name,_type,_uevent_ops) \
 180 struct subsystem _name##_subsys = { \
 181         .kset = { \
 182                 .kobj = { .name = __stringify(_name) }, \
 183                 .ktype = _type, \
 184                 .uevent_ops =_uevent_ops, \
 185         } \
 186 }
 187 #define decl_subsys_name(_varname,_name,_type,_uevent_ops) \
 188 struct subsystem _varname##_subsys = { \
 189         .kset = { \
 190                 .kobj = { .name = __stringify(_name) }, \
 191                 .ktype = _type, \
 192                 .uevent_ops =_uevent_ops, \
 193         } \
 194 }
 195
 196 /* The global /sys/kernel/ subsystem for people to chain off of */
 197 extern struct subsystem kernel_subsys;
 198 /* The global /sys/hypervisor/ subsystem  */
 199 extern struct subsystem hypervisor_subsys;
 200
 201 /**
 202  * Helpers for setting the kset of registered objects.
 203  * Often, a registered object belongs to a kset embedded in a
 204  * subsystem. These do no magic, just make the resulting code
 205  * easier to follow.
 206  */
 207
 208 /**
 209  *      kobj_set_kset_s(obj,subsys) - set kset for embedded kobject.
 210  *      @obj:           ptr to some object type.
 211  *      @subsys:        a subsystem object (not a ptr).
 212  *
 213  *      Can be used for any object type with an embedded ->kobj.
 214  */
 215
 216 #define kobj_set_kset_s(obj,subsys) \
 217         (obj)->kobj.kset = &(subsys).kset
 218
 219 /**
 220  *      kset_set_kset_s(obj,subsys) - set kset for embedded kset.
 221  *      @obj:           ptr to some object type.
 222  *      @subsys:        a subsystem object (not a ptr).
 223  *
 224  *      Can be used for any object type with an embedded ->kset.
 225  *      Sets the kset of @obj's  embedded kobject (via its embedded
 226  *      kset) to @subsys.kset. This makes @obj a member of that
 227  *      kset.
 228  */
 229
 230 #define kset_set_kset_s(obj,subsys) \
 231         (obj)->kset.kobj.kset = &(subsys).kset
 232
 233 /**
 234  *      subsys_set_kset(obj,subsys) - set kset for subsystem
 235  *      @obj:           ptr to some object type.
 236  *      @subsys:        a subsystem object (not a ptr).
 237  *
 238  *      Can be used for any object type with an embedded ->subsys.
 239  *      Sets the kset of @obj's kobject to @subsys.kset. This makes
 240  *      the object a member of that kset.
 241  */
 242
 243 #define subsys_set_kset(obj,_subsys) \
 244         (obj)->subsys.kset.kobj.kset = &(_subsys).kset
 245
 246 extern void subsystem_init(struct subsystem *);
 247 extern int __must_check subsystem_register(struct subsystem *);
 248 extern void subsystem_unregister(struct subsystem *);
 249
 250 static inline struct subsystem * subsys_get(struct subsystem * s)
 251 {
 252         return s ? container_of(kset_get(&s->kset),struct subsystem,kset) : NULL;
 253 }
 254
 255 static inline void subsys_put(struct subsystem * s)
 256 {
 257         kset_put(&s->kset);
 258 }
 259
 260 struct subsys_attribute {
 261         struct attribute attr;
 262         ssize_t (*show)(struct subsystem *, char *);
 263         ssize_t (*store)(struct subsystem *, const char *, size_t);
 264 };
 265
 266 extern int __must_check subsys_create_file(struct subsystem * ,
 267                                         struct subsys_attribute *);
 268
 269 #if defined(CONFIG_HOTPLUG)
 270 int kobject_uevent(struct kobject *kobj, enum kobject_action action);
 271 int kobject_uevent_env(struct kobject *kobj, enum kobject_action action,
 272                         char *envp[]);
 273
 274 int add_uevent_var(char **envp, int num_envp, int *cur_index,
 275                         char *buffer, int buffer_size, int *cur_len,
 276                         const char *format, ...)
 277         __attribute__((format (printf, 7, 8)));
 278 #else
 279 static inline int kobject_uevent(struct kobject *kobj, enum kobject_action action)
 280 { return 0; }
 281 static inline int kobject_uevent_env(struct kobject *kobj,
 282                                       enum kobject_action action,
 283                                       char *envp[])
 284 { return 0; }
 285
 286 static inline int add_uevent_var(char **envp, int num_envp, int *cur_index,
 287                                       char *buffer, int buffer_size, int *cur_len,
 288                                       const char *format, ...)
 289 { return 0; }
 290 #endif
 291
 292 #endif /* __KERNEL__ */
 293 #endif /* _KOBJECT_H_ */